Merge branch 'smp-hotplug-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull smp hotplug cleanups from Thomas Gleixner: "This series is merily a cleanup of code copied around in arch/* and not changing any of the real cpu hotplug horrors yet. I wish I'd had something more substantial for 3.5, but I underestimated the lurking horror..." Fix up trivial conflicts in arch/{arm,sparc,x86}/Kconfig and arch/sparc/include/asm/thread_info_32.h * 'smp-hotplug-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (79 commits) um: Remove leftover declaration of alloc_task_struct_node() task_allocator: Use config switches instead of magic defines sparc: Use common threadinfo allocator score: Use common threadinfo allocator sh-use-common-threadinfo-allocator mn10300: Use common threadinfo allocator powerpc: Use common threadinfo allocator mips: Use common threadinfo allocator hexagon: Use common threadinfo allocator m32r: Use common threadinfo allocator frv: Use common threadinfo allocator cris: Use common threadinfo allocator x86: Use common threadinfo allocator c6x: Use common threadinfo allocator fork: Provide kmemcache based thread_info allocator tile: Use common threadinfo allocator fork: Provide weak arch_release_[task_struct|thread_info] functions fork: Move thread info gfp flags to header fork: Remove the weak insanity sh: Remove cpu_idle_wait() ...
author: Linus Torvalds <torvalds@linux-foundation.org> 2012-05-21 22:43:57 -0400
committer: Linus Torvalds <torvalds@linux-foundation.org> 2012-05-21 22:43:57 -0400
commit: bf67f3a5c456a18f2e8d062f7e88506ef2cd9837 (patch)
tree: 2a2324b2572162059307db82f9238eeb25673a77
parent: 226da0dbc84ed97f448523e2a4cb91c27fa68ed9 (diff)
parent: 203dacbdca977bedaba61ad2fca75d934060a5d5 (diff)
157 files changed, 415 insertions, 1934 deletions
diff --git a/arch/Kconfig b/arch/Kconfig
index 684eb5af439d..bd265a217bd2 100644
--- a/arch/Kconfig
+++ b/arch/Kconfig
@@ -145,6 +145,21 @@ config HAVE_DMA_ATTRS
 config USE_GENERIC_SMP_HELPERS
        bool
+config GENERIC_SMP_IDLE_THREAD
+       bool
+# Select if arch init_task initializer is different to init/init_task.c
+config ARCH_INIT_TASK
+       bool
+# Select if arch has its private alloc_task_struct() function
+config ARCH_TASK_STRUCT_ALLOCATOR
+        bool
+# Select if arch has its private alloc_thread_info() function
+config ARCH_THREAD_INFO_ALLOCATOR
+        bool
 config HAVE_REGS_AND_STACK_ACCESS_API
        bool
        help
diff --git a/arch/alpha/Kconfig b/arch/alpha/Kconfig
index 22e58a99f38b..0893f023efb8 100644
--- a/arch/alpha/Kconfig
+++ b/arch/alpha/Kconfig
@@ -15,6 +15,7 @@ config ALPHA
        select GENERIC_IRQ_SHOW
        select ARCH_WANT_OPTIONAL_GPIOLIB
        select ARCH_HAVE_NMI_SAFE_CMPXCHG
+        select GENERIC_SMP_IDLE_THREAD
        help
          The Alpha is a 64-bit general-purpose processor designed and
          marketed by the Digital Equipment Corporation of blessed memory,
diff --git a/arch/alpha/kernel/Makefile b/arch/alpha/kernel/Makefile
index 7a6d908bb865..84ec46b38f7d 100644
--- a/arch/alpha/kernel/Makefile
+++ b/arch/alpha/kernel/Makefile
@@ -6,7 +6,7 @@ extra-y		:= head.o vmlinux.lds
 asflags-y       := $(KBUILD_CFLAGS)
 ccflags-y       := -Wno-sign-compare
-obj-y    := entry.o traps.o process.o init_task.o osf_sys.o irq.o \
+obj-y    := entry.o traps.o process.o osf_sys.o irq.o \
            irq_alpha.o signal.o setup.o ptrace.o time.o \
            alpha_ksyms.o systbls.o err_common.o io.o
diff --git a/arch/alpha/kernel/smp.c b/arch/alpha/kernel/smp.c
index 50d438db1f6b..35ddc02bfa4a 100644
--- a/arch/alpha/kernel/smp.c
+++ b/arch/alpha/kernel/smp.c
@@ -357,24 +357,10 @@ secondary_cpu_start(int cpuid, struct task_struct *idle)
 * Bring one cpu online.
 */
 static int __cpuinit
-smp_boot_one_cpu(int cpuid)
+smp_boot_one_cpu(int cpuid, struct task_struct *idle)
 {
-        struct task_struct *idle;
        unsigned long timeout;
-        /* Cook up an idler for this guy.  Note that the address we
-           give to kernel_thread is irrelevant -- it's going to start
-           where HWRPB.CPU_restart says to start.  But this gets all
-           the other task-y sort of data structures set up like we
-           wish.  We can't use kernel_thread since we must avoid
-           rescheduling the child.  */
-        idle = fork_idle(cpuid);
-        if (IS_ERR(idle))
-                panic("failed fork for CPU %d", cpuid);
-        DBGS(("smp_boot_one_cpu: CPU %d state 0x%lx flags 0x%lx\n",
-              cpuid, idle->state, idle->flags));
        /* Signal the secondary to wait a moment.  */
        smp_secondary_alive = -1;
@@ -487,9 +473,9 @@ smp_prepare_boot_cpu(void)
 }
 int __cpuinit
-__cpu_up(unsigned int cpu)
+__cpu_up(unsigned int cpu, struct task_struct *tidle)
 {
-        smp_boot_one_cpu(cpu);
+        smp_boot_one_cpu(cpu, tidle);
        return cpu_online(cpu) ? 0 : -ENOSYS;
 }
diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index 554ec1dd89d4..4305ae25652b 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -37,6 +37,7 @@ config ARM
        select CPU_PM if (SUSPEND || CPU_IDLE)
        select GENERIC_PCI_IOMAP
        select HAVE_BPF_JIT
+        select GENERIC_SMP_IDLE_THREAD
        help
          The ARM series is a line of low-power-consumption RISC chip designs
          licensed by ARM Ltd and targeted at embedded applications and
@@ -154,9 +155,6 @@ config ARCH_HAS_CPUFREQ
          and that the relevant menu configurations are displayed for
          it.
-config ARCH_HAS_CPU_IDLE_WAIT
-       def_bool y
 config GENERIC_HWEIGHT
        bool
        default y
diff --git a/arch/arm/Makefile b/arch/arm/Makefile
index aaf96bccd4a0..3b18ef7ad278 100644
--- a/arch/arm/Makefile
+++ b/arch/arm/Makefile
@@ -117,7 +117,7 @@ KBUILD_AFLAGS	+=$(CFLAGS_ABI) $(AFLAGS_THUMB2) $(arch-y) $(tune-y) -include asm/
 CHECKFLAGS      += -D__arm__
 #Default value
-head-y          := arch/arm/kernel/head$(MMUEXT).o arch/arm/kernel/init_task.o
+head-y          := arch/arm/kernel/head$(MMUEXT).o
 textofs-y       := 0x00008000
 textofs-$(CONFIG_ARCH_CLPS711X) := 0x00028000
 # We don't want the htc bootloader to corrupt kernel during resume
diff --git a/arch/arm/include/asm/cpu.h b/arch/arm/include/asm/cpu.h
index 793968173bef..d797223b39d5 100644
--- a/arch/arm/include/asm/cpu.h
+++ b/arch/arm/include/asm/cpu.h
@@ -16,7 +16,6 @@
 struct cpuinfo_arm {
        struct cpu      cpu;
 #ifdef CONFIG_SMP
-        struct task_struct *idle;
        unsigned int    loops_per_jiffy;
 #endif
 };
diff --git a/arch/arm/include/asm/processor.h b/arch/arm/include/asm/processor.h
index 5ac8d3d3e025..d7038fa22343 100644
--- a/arch/arm/include/asm/processor.h
+++ b/arch/arm/include/asm/processor.h
@@ -88,8 +88,6 @@ unsigned long get_wchan(struct task_struct *p);
 #define cpu_relax()                     barrier()
 #endif
-void cpu_idle_wait(void);
 /*
 * Create a new kernel thread
 */
diff --git a/arch/arm/kernel/Makefile b/arch/arm/kernel/Makefile
index 22b0f1e255f0..7ad2d5cf7008 100644
--- a/arch/arm/kernel/Makefile
+++ b/arch/arm/kernel/Makefile
@@ -82,4 +82,4 @@ head-y			:= head$(MMUEXT).o
 obj-$(CONFIG_DEBUG_LL)  += debug.o
 obj-$(CONFIG_EARLY_PRINTK)      += early_printk.o
-extra-y := $(head-y) init_task.o vmlinux.lds
+extra-y := $(head-y) vmlinux.lds
diff --git a/arch/arm/kernel/init_task.c b/arch/arm/kernel/init_task.c
deleted file mode 100644
index e7cbb50dc356..000000000000
--- a/arch/arm/kernel/init_task.c
+++ /dev/null
@@ -1,37 +0,0 @@
-/*
- *  linux/arch/arm/kernel/init_task.c
- */
-#include <linux/mm.h>
-#include <linux/module.h>
-#include <linux/fs.h>
-#include <linux/sched.h>
-#include <linux/init.h>
-#include <linux/init_task.h>
-#include <linux/mqueue.h>
-#include <linux/uaccess.h>
-#include <asm/pgtable.h>
-static struct signal_struct init_signals = INIT_SIGNALS(init_signals);
-static struct sighand_struct init_sighand = INIT_SIGHAND(init_sighand);
-/*
- * Initial thread structure.
- *
- * We need to make sure that this is 8192-byte aligned due to the
- * way process stacks are handled. This is done by making sure
- * the linker maps this in the .text segment right after head.S,
- * and making head.S ensure the proper alignment.
- *
- * The things we do for performance..
- */
-union thread_union init_thread_union __init_task_data =
-        { INIT_THREAD_INFO(init_task) };
-/*
- * Initial task structure.
- *
- * All other task structs will be allocated on slabs in fork.c
- */
-struct task_struct init_task = INIT_TASK(init_task);
-EXPORT_SYMBOL(init_task);
diff --git a/arch/arm/kernel/process.c b/arch/arm/kernel/process.c
index 2b7b017a20cd..19c95ea65b2f 100644
--- a/arch/arm/kernel/process.c
+++ b/arch/arm/kernel/process.c
@@ -157,26 +157,6 @@ EXPORT_SYMBOL(pm_power_off);
 void (*arm_pm_restart)(char str, const char *cmd) = null_restart;
 EXPORT_SYMBOL_GPL(arm_pm_restart);
-static void do_nothing(void *unused)
-{
-}
-/*
- * cpu_idle_wait - Used to ensure that all the CPUs discard old value of
- * pm_idle and update to new pm_idle value. Required while changing pm_idle
- * handler on SMP systems.
- *
- * Caller must have changed pm_idle to the new value before the call. Old
- * pm_idle value will not be used by any CPU after the return of this function.
- */
-void cpu_idle_wait(void)
-{
-        smp_mb();
-        /* kick all the CPUs so that they exit out of pm_idle */
-        smp_call_function(do_nothing, NULL, 1);
-}
-EXPORT_SYMBOL_GPL(cpu_idle_wait);
 /*
 * This is our default idle handler.
 */
diff --git a/arch/arm/kernel/smp.c b/arch/arm/kernel/smp.c
index cf58558ef4b9..b735521a4a54 100644
--- a/arch/arm/kernel/smp.c
+++ b/arch/arm/kernel/smp.c
@@ -60,32 +60,11 @@ enum ipi_msg_type {
 static DECLARE_COMPLETION(cpu_running);
-int __cpuinit __cpu_up(unsigned int cpu)
+int __cpuinit __cpu_up(unsigned int cpu, struct task_struct *idle)
 {
-        struct cpuinfo_arm *ci = &per_cpu(cpu_data, cpu);
-        struct task_struct *idle = ci->idle;
        int ret;
        /*
-         * Spawn a new process manually, if not already done.
-         * Grab a pointer to its task struct so we can mess with it
-         */
-        if (!idle) {
-                idle = fork_idle(cpu);
-                if (IS_ERR(idle)) {
-                        printk(KERN_ERR "CPU%u: fork() failed\n", cpu);
-                        return PTR_ERR(idle);
-                }
-                ci->idle = idle;
-        } else {
-                /*
-                 * Since this idle thread is being re-used, call
-                 * init_idle() to reinitialize the thread structure.
-                 */
-                init_idle(idle, cpu);
-        }
-        /*
         * We need to tell the secondary core where to find
         * its stack and the page tables.
         */
@@ -318,9 +297,6 @@ void __init smp_cpus_done(unsigned int max_cpus)
 void __init smp_prepare_boot_cpu(void)
 {
-        unsigned int cpu = smp_processor_id();
-        per_cpu(cpu_data, cpu).idle = current;
 }
 void __init smp_prepare_cpus(unsigned int max_cpus)
diff --git a/arch/avr32/kernel/Makefile b/arch/avr32/kernel/Makefile
index 18229d0d1861..9e2c465ef3a6 100644
--- a/arch/avr32/kernel/Makefile
+++ b/arch/avr32/kernel/Makefile
@@ -8,7 +8,7 @@ obj-$(CONFIG_SUBARCH_AVR32B)	+= entry-avr32b.o
 obj-y                           += syscall_table.o syscall-stubs.o irq.o
 obj-y                           += setup.o traps.o ocd.o ptrace.o
 obj-y                           += signal.o sys_avr32.o process.o time.o
-obj-y                           += init_task.o switch_to.o cpu.o
+obj-y                           += switch_to.o cpu.o
 obj-$(CONFIG_MODULES)           += module.o avr32_ksyms.o
 obj-$(CONFIG_KPROBES)           += kprobes.o
 obj-$(CONFIG_STACKTRACE)        += stacktrace.o
diff --git a/arch/avr32/kernel/init_task.c b/arch/avr32/kernel/init_task.c
deleted file mode 100644
index 6b2343e6fe33..000000000000
--- a/arch/avr32/kernel/init_task.c
+++ /dev/null
@@ -1,31 +0,0 @@
-/*
- * Copyright (C) 2004-2006 Atmel Corporation
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License version 2 as
- * published by the Free Software Foundation.
- */
-#include <linux/module.h>
-#include <linux/fs.h>
-#include <linux/sched.h>
-#include <linux/init_task.h>
-#include <linux/mqueue.h>
-#include <asm/pgtable.h>
-static struct signal_struct init_signals = INIT_SIGNALS(init_signals);
-static struct sighand_struct init_sighand = INIT_SIGHAND(init_sighand);
-/*
- * Initial thread structure. Must be aligned on an 8192-byte boundary.
- */
-union thread_union init_thread_union __init_task_data =
-        { INIT_THREAD_INFO(init_task) };
-/*
- * Initial task structure.
- *
- * All other task structs will be allocated on slabs in fork.c
- */
-struct task_struct init_task = INIT_TASK(init_task);
-EXPORT_SYMBOL(init_task);
diff --git a/arch/blackfin/Kconfig b/arch/blackfin/Kconfig
index 383e7ecda923..7f3c589cc024 100644
--- a/arch/blackfin/Kconfig
+++ b/arch/blackfin/Kconfig
@@ -37,6 +37,7 @@ config BLACKFIN
        select GENERIC_IRQ_PROBE
        select IRQ_PER_CPU if SMP
        select HAVE_NMI_WATCHDOG if NMI_WATCHDOG
+        select GENERIC_SMP_IDLE_THREAD
 config GENERIC_CSUM
        def_bool y
diff --git a/arch/blackfin/Makefile b/arch/blackfin/Makefile
index 74fdf679da01..d3d7e64ca96d 100644
--- a/arch/blackfin/Makefile
+++ b/arch/blackfin/Makefile
@@ -109,8 +109,6 @@ KBUILD_AFLAGS += -mcpu=$(CPU_REV)
 CHECKFLAGS_SILICON = $(shell echo "" | $(CPP) $(KBUILD_CFLAGS) -dD - 2>/dev/null | awk '$$2 == "__SILICON_REVISION__" { print $$3 }')
 CHECKFLAGS += -D__SILICON_REVISION__=$(CHECKFLAGS_SILICON) -D__bfin__
-head-y   := arch/$(ARCH)/kernel/init_task.o
 core-y   += arch/$(ARCH)/kernel/ arch/$(ARCH)/mm/ arch/$(ARCH)/mach-common/
 # If we have a machine-specific directory, then include it in the build.
diff --git a/arch/blackfin/kernel/Makefile b/arch/blackfin/kernel/Makefile
index 9a0d6d706443..08e6625106be 100644
--- a/arch/blackfin/kernel/Makefile
+++ b/arch/blackfin/kernel/Makefile
@@ -2,7 +2,7 @@
 # arch/blackfin/kernel/Makefile
 #
-extra-y := init_task.o vmlinux.lds
+extra-y := vmlinux.lds
 obj-y := \
        entry.o process.o bfin_ksyms.o ptrace.o setup.o signal.o \
diff --git a/arch/blackfin/kernel/init_task.c b/arch/blackfin/kernel/init_task.c
deleted file mode 100644
index d3970e8acd1a..000000000000
--- a/arch/blackfin/kernel/init_task.c
+++ /dev/null
@@ -1,32 +0,0 @@
-/*
- * Copyright 2004-2009 Analog Devices Inc.
- *
- * Licensed under the GPL-2 or later
- */
-#include <linux/mm.h>
-#include <linux/module.h>
-#include <linux/init_task.h>
-#include <linux/mqueue.h>
-#include <linux/fs.h>
-static struct signal_struct init_signals = INIT_SIGNALS(init_signals);
-static struct sighand_struct init_sighand = INIT_SIGHAND(init_sighand);
-/*
- * Initial task structure.
- *
- * All other task structs will be allocated on slabs in fork.c
- */
-struct task_struct init_task = INIT_TASK(init_task);
-EXPORT_SYMBOL(init_task);
-/*
- * Initial thread structure.
- *
- * We need to make sure that this is 8192-byte aligned due to the
- * way process stacks are handled. This is done by having a special
- * "init_task" linker map entry.
- */
-union thread_union init_thread_union
-    __init_task_data = {
-INIT_THREAD_INFO(init_task)};
diff --git a/arch/blackfin/mach-common/smp.c b/arch/blackfin/mach-common/smp.c
index ac8f8a43158c..00bbe672b3b3 100644
--- a/arch/blackfin/mach-common/smp.c
+++ b/arch/blackfin/mach-common/smp.c
@@ -340,27 +340,10 @@ void smp_send_stop(void)
        return;
 }
-int __cpuinit __cpu_up(unsigned int cpu)
+int __cpuinit __cpu_up(unsigned int cpu, struct task_struct *idle)
 {
        int ret;
-        struct blackfin_cpudata *ci = &per_cpu(cpu_data, cpu);
-        struct task_struct *idle = ci->idle;
-        if (idle) {
-                free_task(idle);
-                idle = NULL;
-        }
-        if (!idle) {
-                idle = fork_idle(cpu);
-                if (IS_ERR(idle)) {
-                        printk(KERN_ERR "CPU%u: fork() failed\n", cpu);
-                        return PTR_ERR(idle);
-                }
-                ci->idle = idle;
-        } else {
-                init_idle(idle, cpu);
-        }
        secondary_stack = task_stack_page(idle) + THREAD_SIZE;
        ret = platform_boot_secondary(cpu, idle);
diff --git a/arch/c6x/include/asm/thread_info.h b/arch/c6x/include/asm/thread_info.h
index fd99148cda9d..1710bcbb8d09 100644
--- a/arch/c6x/include/asm/thread_info.h
+++ b/arch/c6x/include/asm/thread_info.h
@@ -20,11 +20,11 @@
 #ifdef CONFIG_4KSTACKS
 #define THREAD_SIZE             4096
 #define THREAD_SHIFT            12
-#define THREAD_ORDER            0
+#define THREAD_SIZE_ORDER       0
 #else
 #define THREAD_SIZE             8192
 #define THREAD_SHIFT            13
-#define THREAD_ORDER            1
+#define THREAD_SIZE_ORDER       1
 #endif
 #define THREAD_START_SP         (THREAD_SIZE - 8)
@@ -80,19 +80,6 @@ struct thread_info *current_thread_info(void)
        return ti;
 }
-#define __HAVE_ARCH_THREAD_INFO_ALLOCATOR
-/* thread information allocation */
-#ifdef CONFIG_DEBUG_STACK_USAGE
-#define THREAD_FLAGS (GFP_KERNEL | __GFP_NOTRACK | __GFP_ZERO)
-#else
-#define THREAD_FLAGS (GFP_KERNEL | __GFP_NOTRACK)
-#endif
-#define alloc_thread_info_node(tsk, node)       \
-        ((struct thread_info *)__get_free_pages(THREAD_FLAGS, THREAD_ORDER))
-#define free_thread_info(ti)    free_pages((unsigned long) (ti), THREAD_ORDER)
 #define get_thread_info(ti)     get_task_struct((ti)->task)
 #define put_thread_info(ti)     put_task_struct((ti)->task)
 #endif /* __ASSEMBLY__ */
diff --git a/arch/c6x/kernel/process.c b/arch/c6x/kernel/process.c
index 7ca8c41b03cd..45e924a636a0 100644
--- a/arch/c6x/kernel/process.c
+++ b/arch/c6x/kernel/process.c
@@ -26,22 +26,6 @@ void	(*c6x_halt)(void);
 extern asmlinkage void ret_from_fork(void);
-static struct signal_struct init_signals = INIT_SIGNALS(init_signals);
-static struct sighand_struct init_sighand = INIT_SIGHAND(init_sighand);
-/*
- * Initial thread structure.
- */
-union thread_union init_thread_union __init_task_data = {
-        INIT_THREAD_INFO(init_task)
-};
-/*
- * Initial task structure.
- */
-struct task_struct init_task = INIT_TASK(init_task);
-EXPORT_SYMBOL(init_task);
 /*
 * power off function, if any
 */
diff --git a/arch/cris/Kconfig b/arch/cris/Kconfig
index b3abfb08aa5c..2995035812ec 100644
--- a/arch/cris/Kconfig
+++ b/arch/cris/Kconfig
@@ -49,6 +49,7 @@ config CRIS
        select HAVE_GENERIC_HARDIRQS
        select GENERIC_IRQ_SHOW
        select GENERIC_IOMAP
+        select GENERIC_SMP_IDLE_THREAD if ETRAX_ARCH_V32
 config HZ
        int
diff --git a/arch/cris/arch-v32/kernel/smp.c b/arch/cris/arch-v32/kernel/smp.c
index 0b99df72d2a4..ebe2cb30bd11 100644
--- a/arch/cris/arch-v32/kernel/smp.c
+++ b/arch/cris/arch-v32/kernel/smp.c
@@ -108,17 +108,12 @@ void __init smp_cpus_done(unsigned int max_cpus)
 /* Bring one cpu online.*/
 static int __init
-smp_boot_one_cpu(int cpuid)
+smp_boot_one_cpu(int cpuid, struct task_struct idle)
 {
        unsigned timeout;
-        struct task_struct *idle;
        cpumask_t cpu_mask;
        cpumask_clear(&cpu_mask);
-        idle = fork_idle(cpuid);
-        if (IS_ERR(idle))
-                panic("SMP: fork failed for CPU:%d", cpuid);
        task_thread_info(idle)->cpu = cpuid;
        /* Information to the CPU that is about to boot */
@@ -142,9 +137,6 @@ smp_boot_one_cpu(int cpuid)
                barrier();
        }
-        put_task_struct(idle);
-        idle = NULL;
        printk(KERN_CRIT "SMP: CPU:%d is stuck.\n", cpuid);
        return -1;
 }
@@ -207,9 +199,9 @@ int setup_profiling_timer(unsigned int multiplier)
 */
 unsigned long cache_decay_ticks = 1;
-int __cpuinit __cpu_up(unsigned int cpu)
+int __cpuinit __cpu_up(unsigned int cpu, struct task_struct *tidle)
 {
-        smp_boot_one_cpu(cpu);
+        smp_boot_one_cpu(cpu, tidle);
        return cpu_online(cpu) ? 0 : -ENOSYS;
 }
diff --git a/arch/cris/include/asm/processor.h b/arch/cris/include/asm/processor.h
index 4210d72a6667..8dc56ef08712 100644
--- a/arch/cris/include/asm/processor.h
+++ b/arch/cris/include/asm/processor.h
@@ -25,13 +25,12 @@ struct task_struct;
 */
 #define TASK_UNMAPPED_BASE      (PAGE_ALIGN(TASK_SIZE / 3))
-/* THREAD_SIZE is the size of the task_struct/kernel_stack combo.
+/* THREAD_SIZE is the size of the thread_info/kernel_stack combo.
 * normally, the stack is found by doing something like p + THREAD_SIZE
 * in CRIS, a page is 8192 bytes, which seems like a sane size
 */
 #define THREAD_SIZE       PAGE_SIZE
-#define KERNEL_STACK_SIZE PAGE_SIZE
+#define THREAD_SIZE_ORDER (0)
 /*
 * At user->kernel entry, the pt_regs struct is stacked on the top of the kernel-stack.
diff --git a/arch/cris/include/asm/thread_info.h b/arch/cris/include/asm/thread_info.h
index 29b92884d793..5b1c448df5c0 100644
--- a/arch/cris/include/asm/thread_info.h
+++ b/arch/cris/include/asm/thread_info.h
@@ -65,12 +65,6 @@ struct thread_info {
 #define init_thread_info        (init_thread_union.thread_info)
-#define __HAVE_ARCH_THREAD_INFO_ALLOCATOR
-/* thread information allocation */
-#define alloc_thread_info_node(tsk, node)       \
-        ((struct thread_info *) __get_free_pages(GFP_KERNEL, 1))
-#define free_thread_info(ti) free_pages((unsigned long) (ti), 1)
 #endif /* !__ASSEMBLY__ */
 /*
diff --git a/arch/cris/kernel/process.c b/arch/cris/kernel/process.c
index 891dad85e8bd..66fd01728790 100644
--- a/arch/cris/kernel/process.c
+++ b/arch/cris/kernel/process.c
@@ -29,34 +29,6 @@
 //#define DEBUG
 /*
- * Initial task structure. Make this a per-architecture thing,
- * because different architectures tend to have different
- * alignment requirements and potentially different initial
- * setup.
- */
-static struct signal_struct init_signals = INIT_SIGNALS(init_signals);
-static struct sighand_struct init_sighand = INIT_SIGHAND(init_sighand);
-/*
- * Initial thread structure.
- *
- * We need to make sure that this is 8192-byte aligned due to the
- * way process stacks are handled. This is done by having a special
- * "init_task" linker map entry..
- */
-union thread_union init_thread_union __init_task_data =
-        { INIT_THREAD_INFO(init_task) };
-/*
- * Initial task structure.
- *
- * All other task structs will be allocated on slabs in fork.c
- */
-struct task_struct init_task = INIT_TASK(init_task);
-EXPORT_SYMBOL(init_task);
-/*
 * The hlt_counter, disable_hlt and enable_hlt is just here as a hook if
 * there would ever be a halt sequence (for power save when idle) with
 * some largish delay when halting or resuming *and* a driver that can't
diff --git a/arch/frv/Makefile b/arch/frv/Makefile
index 7ff84575b186..4d1b1e9baef1 100644
--- a/arch/frv/Makefile
+++ b/arch/frv/Makefile
@@ -81,7 +81,7 @@ ifdef CONFIG_DEBUG_INFO
 KBUILD_AFLAGS   += -Wa,--gdwarf2
 endif
-head-y          := arch/frv/kernel/head.o arch/frv/kernel/init_task.o
+head-y          := arch/frv/kernel/head.o
 core-y          += arch/frv/kernel/ arch/frv/mm/
 libs-y          += arch/frv/lib/
diff --git a/arch/frv/include/asm/thread_info.h b/arch/frv/include/asm/thread_info.h
index 92d83ea99ae5..54ab13a0de41 100644
--- a/arch/frv/include/asm/thread_info.h
+++ b/arch/frv/include/asm/thread_info.h
@@ -21,8 +21,6 @@
 #define THREAD_SIZE             8192
-#define __HAVE_ARCH_TASK_STRUCT_ALLOCATOR
 /*
 * low level task data that entry.S needs immediate access to
 * - this struct should fit entirely inside of one cache line
@@ -82,19 +80,6 @@ register struct thread_info *__current_thread_info asm("gr15");
 #define current_thread_info() ({ __current_thread_info; })
-#define __HAVE_ARCH_THREAD_INFO_ALLOCATOR
-/* thread information allocation */
-#ifdef CONFIG_DEBUG_STACK_USAGE
-#define alloc_thread_info_node(tsk, node)                       \
-                kzalloc_node(THREAD_SIZE, GFP_KERNEL, node)
-#else
-#define alloc_thread_info_node(tsk, node)                       \
-                kmalloc_node(THREAD_SIZE, GFP_KERNEL, node)
-#endif
-#define free_thread_info(info)  kfree(info)
 #endif /* __ASSEMBLY__ */
 /*
diff --git a/arch/frv/kernel/Makefile b/arch/frv/kernel/Makefile
index c36f70b6699a..ad4087b69968 100644
--- a/arch/frv/kernel/Makefile
+++ b/arch/frv/kernel/Makefile
@@ -5,7 +5,7 @@
 heads-y                         := head-uc-fr401.o head-uc-fr451.o head-uc-fr555.o
 heads-$(CONFIG_MMU)             := head-mmu-fr451.o
-extra-y:= head.o init_task.o vmlinux.lds
+extra-y:= head.o vmlinux.lds
 obj-y := $(heads-y) entry.o entry-table.o break.o switch_to.o kernel_thread.o \
         kernel_execve.o process.o traps.o ptrace.o signal.o dma.o \
diff --git a/arch/frv/kernel/init_task.c b/arch/frv/kernel/init_task.c
deleted file mode 100644
index 3c3e0b336a9d..000000000000
--- a/arch/frv/kernel/init_task.c
+++ /dev/null
@@ -1,32 +0,0 @@
-#include <linux/mm.h>
-#include <linux/module.h>
-#include <linux/sched.h>
-#include <linux/init.h>
-#include <linux/init_task.h>
-#include <linux/fs.h>
-#include <linux/mqueue.h>
-#include <asm/uaccess.h>
-#include <asm/pgtable.h>
-static struct signal_struct init_signals = INIT_SIGNALS(init_signals);
-static struct sighand_struct init_sighand = INIT_SIGHAND(init_sighand);
-/*
- * Initial thread structure.
- *
- * We need to make sure that this is THREAD_SIZE aligned due to the
- * way process stacks are handled. This is done by having a special
- * "init_task" linker map entry..
- */
-union thread_union init_thread_union __init_task_data =
-        { INIT_THREAD_INFO(init_task) };
-/*
- * Initial task structure.
- *
- * All other task structs will be allocated on slabs in fork.c
- */
-struct task_struct init_task = INIT_TASK(init_task);
-EXPORT_SYMBOL(init_task);
diff --git a/arch/frv/kernel/process.c b/arch/frv/kernel/process.c
index d4de48bd5efe..ed09e9e2c653 100644
--- a/arch/frv/kernel/process.c
+++ b/arch/frv/kernel/process.c
@@ -43,21 +43,6 @@ asmlinkage void ret_from_fork(void);
 void (*pm_power_off)(void);
 EXPORT_SYMBOL(pm_power_off);
-struct task_struct *alloc_task_struct_node(int node)
-{
-        struct task_struct *p = kmalloc_node(THREAD_SIZE, GFP_KERNEL, node);
-        if (p)
-                atomic_set((atomic_t *)(p+1), 1);
-        return p;
-}
-void free_task_struct(struct task_struct *p)
-{
-        if (atomic_dec_and_test((atomic_t *)(p+1)))
-                kfree(p);
-}
 static void core_sleep_idle(void)
 {
 #ifdef LED_DEBUG_SLEEP
diff --git a/arch/h8300/kernel/Makefile b/arch/h8300/kernel/Makefile
index 8d4d2a54be9e..1cc57f872d34 100644
--- a/arch/h8300/kernel/Makefile
+++ b/arch/h8300/kernel/Makefile
@@ -6,7 +6,7 @@ extra-y := vmlinux.lds
 obj-y := process.o traps.o ptrace.o irq.o \
         sys_h8300.o time.o signal.o \
-         setup.o gpio.o init_task.o syscalls.o \
+         setup.o gpio.o syscalls.o \
         entry.o timer/
 obj-$(CONFIG_MODULES) += module.o h8300_ksyms.o 
diff --git a/arch/h8300/kernel/init_task.c b/arch/h8300/kernel/init_task.c
deleted file mode 100644
index 54c1062ee80e..000000000000
--- a/arch/h8300/kernel/init_task.c
+++ /dev/null
@@ -1,36 +0,0 @@
-/*
- *  linux/arch/h8300/kernel/init_task.c
- */
-#include <linux/mm.h>
-#include <linux/module.h>
-#include <linux/sched.h>
-#include <linux/init.h>
-#include <linux/init_task.h>
-#include <linux/fs.h>
-#include <linux/mqueue.h>
-#include <asm/uaccess.h>
-#include <asm/pgtable.h>
-static struct signal_struct init_signals = INIT_SIGNALS(init_signals);
-static struct sighand_struct init_sighand = INIT_SIGHAND(init_sighand);
-/*
- * Initial task structure.
- *
- * All other task structs will be allocated on slabs in fork.c
- */
-__asm__(".align 4");
-struct task_struct init_task = INIT_TASK(init_task);
-EXPORT_SYMBOL(init_task);
-/*
- * Initial thread structure.
- *
- * We need to make sure that this is 8192-byte aligned due to the
- * way process stacks are handled. This is done by having a special
- * "init_task" linker map entry..
- */
-union thread_union init_thread_union __init_task_data =
-        { INIT_THREAD_INFO(init_task) };
diff --git a/arch/hexagon/Kconfig b/arch/hexagon/Kconfig
index 9059e3905887..d2e4a3330336 100644
--- a/arch/hexagon/Kconfig
+++ b/arch/hexagon/Kconfig
@@ -27,6 +27,7 @@ config HEXAGON
        select HAVE_ARCH_TRACEHOOK
        select NO_IOPORT
        select GENERIC_IOMAP
+        select GENERIC_SMP_IDLE_THREAD
        # mostly generic routines, with some accelerated ones
        ---help---
          Qualcomm Hexagon is a processor architecture designed for high
diff --git a/arch/hexagon/Makefile b/arch/hexagon/Makefile
index 0c4de8790fd5..e27d030846ae 100644
--- a/arch/hexagon/Makefile
+++ b/arch/hexagon/Makefile
@@ -45,8 +45,7 @@ KBUILD_AFLAGS += -DTHREADINFO_REG=$(TIR_NAME)
 LIBGCC := $(shell $(CC) $(KBUILD_CFLAGS) -print-libgcc-file-name)
 libs-y += $(LIBGCC)
-head-y := arch/hexagon/kernel/head.o \
+head-y := arch/hexagon/kernel/head.o
-        arch/hexagon/kernel/init_task.o
 core-y += arch/hexagon/kernel/ \
        arch/hexagon/mm/ \
diff --git a/arch/hexagon/include/asm/thread_info.h b/arch/hexagon/include/asm/thread_info.h
index 9c2934ff5756..4f936a7ee847 100644
--- a/arch/hexagon/include/asm/thread_info.h
+++ b/arch/hexagon/include/asm/thread_info.h
@@ -31,15 +31,7 @@
 #define THREAD_SHIFT            12
 #define THREAD_SIZE             (1<<THREAD_SHIFT)
-#if THREAD_SHIFT >= PAGE_SHIFT
 #define THREAD_SIZE_ORDER       (THREAD_SHIFT - PAGE_SHIFT)
-#else  /*  don't use standard allocator  */
-#define __HAVE_ARCH_THREAD_INFO_ALLOCATOR
-extern struct thread_info *alloc_thread_info_node(struct task_struct *tsk, int node);
-extern void free_thread_info(struct thread_info *ti);
-#endif
 #ifndef __ASSEMBLY__
diff --git a/arch/hexagon/kernel/Makefile b/arch/hexagon/kernel/Makefile
index 3689f3754d09..536aec093e62 100644
--- a/arch/hexagon/kernel/Makefile
+++ b/arch/hexagon/kernel/Makefile
@@ -1,4 +1,4 @@
-extra-y := head.o vmlinux.lds init_task.o
+extra-y := head.o vmlinux.lds
 obj-$(CONFIG_SMP) += smp.o topology.o
diff --git a/arch/hexagon/kernel/init_task.c b/arch/hexagon/kernel/init_task.c
deleted file mode 100644
index 73283d3edf09..000000000000
--- a/arch/hexagon/kernel/init_task.c
+++ /dev/null
@@ -1,54 +0,0 @@
-/*
- * Init task definition
- *
- * Copyright (c) 2010-2011, Code Aurora Forum. All rights reserved.
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License version 2 and
- * only version 2 as published by the Free Software Foundation.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, write to the Free Software
- * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
- * 02110-1301, USA.
- */
-#include <linux/mm.h>
-#include <linux/module.h>
-#include <linux/sched.h>
-#include <linux/init_task.h>
-#include <linux/fs.h>
-#include <linux/mqueue.h>
-#include <asm/thread_info.h>
-#include <asm/uaccess.h>
-#include <asm/pgtable.h>
-static struct signal_struct init_signals = INIT_SIGNALS(init_signals);
-static struct sighand_struct init_sighand = INIT_SIGHAND(init_sighand);
-/*
- * Initial thread structure.
- *
- * We need to make sure that this is 8192-byte aligned due to the
- * way process stacks are handled. This is done by making sure
- * the linker maps this in the .text segment right after head.S,
- * and making head.S ensure the proper alignment.
- */
-union thread_union init_thread_union
-        __attribute__((__section__(".data.init_task"),
-                __aligned__(THREAD_SIZE))) = {
-                        INIT_THREAD_INFO(init_task)
-                };
-/*
- * Initial task structure.
- *
- * All other task structs will be allocated on slabs in fork.c
- */
-struct task_struct init_task = INIT_TASK(init_task);
-EXPORT_SYMBOL(init_task);
diff --git a/arch/hexagon/kernel/process.c b/arch/hexagon/kernel/process.c
index ff02821bfb7e..af51de63b835 100644
--- a/arch/hexagon/kernel/process.c
+++ b/arch/hexagon/kernel/process.c
@@ -234,43 +234,6 @@ unsigned long get_wchan(struct task_struct *p)
 }
 /*
- * Borrowed from PowerPC -- basically allow smaller kernel stacks if we
- * go crazy with the page sizes.
- */
-#if THREAD_SHIFT < PAGE_SHIFT
-static struct kmem_cache *thread_info_cache;
-struct thread_info *alloc_thread_info_node(struct task_struct *tsk, int node)
-{
-        struct thread_info *ti;
-        ti = kmem_cache_alloc_node(thread_info_cache, GFP_KERNEL, node);
-        if (unlikely(ti == NULL))
-                return NULL;
-#ifdef CONFIG_DEBUG_STACK_USAGE
-        memset(ti, 0, THREAD_SIZE);
-#endif
-        return ti;
-}
-void free_thread_info(struct thread_info *ti)
-{
-        kmem_cache_free(thread_info_cache, ti);
-}
-/*  Weak symbol; called by init/main.c  */
-void thread_info_cache_init(void)
-{
-        thread_info_cache = kmem_cache_create("thread_info", THREAD_SIZE,
-                                              THREAD_SIZE, 0, NULL);
-        BUG_ON(thread_info_cache == NULL);
-}
-#endif /* THREAD_SHIFT < PAGE_SHIFT */
-/*
 * Required placeholder.
 */
 int dump_fpu(struct pt_regs *regs, elf_fpregset_t *fpu)
diff --git a/arch/hexagon/kernel/smp.c b/arch/hexagon/kernel/smp.c
index 1298141874a3..f7264621e58d 100644
--- a/arch/hexagon/kernel/smp.c
+++ b/arch/hexagon/kernel/smp.c
@@ -196,18 +196,11 @@ void __cpuinit start_secondary(void)
 * maintains control until "cpu_online(cpu)" is set.
 */
-int __cpuinit __cpu_up(unsigned int cpu)
+int __cpuinit __cpu_up(unsigned int cpu, struct task_struct *idle)
 {
-        struct task_struct *idle;
+        struct thread_info *thread = (struct thread_info *)idle->stack;
-        struct thread_info *thread;
        void *stack_start;
-        /*  Create new init task for the CPU  */
-        idle = fork_idle(cpu);
-        if (IS_ERR(idle))
-                panic(KERN_ERR "fork_idle failed\n");
-        thread = (struct thread_info *)idle->stack;
        thread->cpu = cpu;
        /*  Boot to the head.  */
diff --git a/arch/ia64/Kconfig b/arch/ia64/Kconfig
index bd7266903bf8..ba667b60f32d 100644
--- a/arch/ia64/Kconfig
+++ b/arch/ia64/Kconfig
@@ -33,6 +33,10 @@ config IA64
        select ARCH_WANT_OPTIONAL_GPIOLIB
        select ARCH_HAVE_NMI_SAFE_CMPXCHG
        select GENERIC_IOMAP
+        select GENERIC_SMP_IDLE_THREAD
+        select ARCH_INIT_TASK
+        select ARCH_TASK_STRUCT_ALLOCATOR
+        select ARCH_THREAD_INFO_ALLOCATOR
        default y
        help
          The Itanium Processor Family is Intel's 64-bit successor to
diff --git a/arch/ia64/include/asm/processor.h b/arch/ia64/include/asm/processor.h
index 483f6c6a4238..f92f67aba618 100644
--- a/arch/ia64/include/asm/processor.h
+++ b/arch/ia64/include/asm/processor.h
@@ -723,7 +723,6 @@ extern unsigned long boot_option_idle_override;
 enum idle_boot_override {IDLE_NO_OVERRIDE=0, IDLE_HALT, IDLE_FORCE_MWAIT,
                         IDLE_NOMWAIT, IDLE_POLL};
-void cpu_idle_wait(void);
 void default_idle(void);
 #define ia64_platform_is(x) (strcmp(x, platform_name) == 0)
diff --git a/arch/ia64/include/asm/thread_info.h b/arch/ia64/include/asm/thread_info.h
index e054bcc4273c..310d9734f02d 100644
--- a/arch/ia64/include/asm/thread_info.h
+++ b/arch/ia64/include/asm/thread_info.h
@@ -54,8 +54,6 @@ struct thread_info {
        },                                      \
 }
-#define __HAVE_ARCH_THREAD_INFO_ALLOCATOR
 #ifndef ASM_OFFSETS_C
 /* how to get the thread information struct from C */
 #define current_thread_info()   ((struct thread_info *) ((char *) current + IA64_TASK_SIZE))
@@ -84,7 +82,6 @@ struct thread_info {
 #endif
 #define end_of_stack(p) (unsigned long *)((void *)(p) + IA64_RBS_OFFSET)
-#define __HAVE_ARCH_TASK_STRUCT_ALLOCATOR
 #define alloc_task_struct_node(node)                                            \
 ({                                                                              \
        struct page *page = alloc_pages_node(node, GFP_KERNEL | __GFP_COMP,     \
diff --git a/arch/ia64/kernel/process.c b/arch/ia64/kernel/process.c
index ce74e143aea3..5e0e86ddb12f 100644
--- a/arch/ia64/kernel/process.c
+++ b/arch/ia64/kernel/process.c
@@ -273,26 +273,6 @@ static inline void play_dead(void)
 }
 #endif /* CONFIG_HOTPLUG_CPU */
-static void do_nothing(void *unused)
-{
-}
-/*
- * cpu_idle_wait - Used to ensure that all the CPUs discard old value of
- * pm_idle and update to new pm_idle value. Required while changing pm_idle
- * handler on SMP systems.
- *
- * Caller must have changed pm_idle to the new value before the call. Old
- * pm_idle value will not be used by any CPU after the return of this function.
- */
-void cpu_idle_wait(void)
-{
-        smp_mb();
-        /* kick all the CPUs so that they exit out of pm_idle */
-        smp_call_function(do_nothing, NULL, 1);
-}
-EXPORT_SYMBOL_GPL(cpu_idle_wait);
 void __attribute__((noreturn))
 cpu_idle (void)
 {
diff --git a/arch/ia64/kernel/smpboot.c b/arch/ia64/kernel/smpboot.c
index 796f6a5b966a..1113b8aba07f 100644
--- a/arch/ia64/kernel/smpboot.c
+++ b/arch/ia64/kernel/smpboot.c
@@ -75,13 +75,6 @@
 #endif
 /*
- * Store all idle threads, this can be reused instead of creating
- * a new thread. Also avoids complicated thread destroy functionality
- * for idle threads.
- */
-struct task_struct *idle_thread_array[NR_CPUS];
-/*
 * Global array allocated for NR_CPUS at boot time
 */
 struct sal_to_os_boot sal_boot_rendez_state[NR_CPUS];
@@ -94,13 +87,7 @@ struct sal_to_os_boot *sal_state_for_booting_cpu = &sal_boot_rendez_state[0];
 #define set_brendez_area(x) (sal_state_for_booting_cpu = &sal_boot_rendez_state[(x)]);
-#define get_idle_for_cpu(x)             (idle_thread_array[(x)])
-#define set_idle_for_cpu(x,p)   (idle_thread_array[(x)] = (p))
 #else
-#define get_idle_for_cpu(x)             (NULL)
-#define set_idle_for_cpu(x,p)
 #define set_brendez_area(x)
 #endif
@@ -480,54 +467,12 @@ struct pt_regs * __cpuinit idle_regs(struct pt_regs *regs)
        return NULL;
 }
-struct create_idle {
-        struct work_struct work;
-        struct task_struct *idle;
-        struct completion done;
-        int cpu;
-};
-void __cpuinit
-do_fork_idle(struct work_struct *work)
-{
-        struct create_idle *c_idle =
-                container_of(work, struct create_idle, work);
-        c_idle->idle = fork_idle(c_idle->cpu);
-        complete(&c_idle->done);
-}
 static int __cpuinit
-do_boot_cpu (int sapicid, int cpu)
+do_boot_cpu (int sapicid, int cpu, struct task_struct *idle)
 {
        int timeout;
-        struct create_idle c_idle = {
-                .work = __WORK_INITIALIZER(c_idle.work, do_fork_idle),
-                .cpu    = cpu,
-                .done   = COMPLETION_INITIALIZER(c_idle.done),
-        };
-        /*
-         * We can't use kernel_thread since we must avoid to
-         * reschedule the child.
-         */
-        c_idle.idle = get_idle_for_cpu(cpu);
-        if (c_idle.idle) {
-                init_idle(c_idle.idle, cpu);
-                goto do_rest;
-        }
-        schedule_work(&c_idle.work);
-        wait_for_completion(&c_idle.done);
-        if (IS_ERR(c_idle.idle))
-                panic("failed fork for CPU %d", cpu);
-        set_idle_for_cpu(cpu, c_idle.idle);
-do_rest:
-        task_for_booting_cpu = c_idle.idle;
+        task_for_booting_cpu = idle;
        Dprintk("Sending wakeup vector %lu to AP 0x%x/0x%x.\n", ap_wakeup_vector, cpu, sapicid);
        set_brendez_area(cpu);
@@ -793,7 +738,7 @@ set_cpu_sibling_map(int cpu)
 }
 int __cpuinit
-__cpu_up (unsigned int cpu)
+__cpu_up(unsigned int cpu, struct task_struct *tidle)
 {
        int ret;
        int sapicid;
@@ -811,7 +756,7 @@ __cpu_up (unsigned int cpu)
        per_cpu(cpu_state, cpu) = CPU_UP_PREPARE;
        /* Processor goes to start_secondary(), sets online flag */
-        ret = do_boot_cpu(sapicid, cpu);
+        ret = do_boot_cpu(sapicid, cpu, tidle);
        if (ret < 0)
                return ret;
diff --git a/arch/m32r/Makefile b/arch/m32r/Makefile
index 8ff5ba0ea26c..def8dd0b6bc5 100644
--- a/arch/m32r/Makefile
+++ b/arch/m32r/Makefile
@@ -31,7 +31,7 @@ KBUILD_AFLAGS += $(aflags-y)
 CHECKFLAGS      += -D__m32r__ -D__BIG_ENDIAN__=1
-head-y  := arch/m32r/kernel/head.o arch/m32r/kernel/init_task.o
+head-y  := arch/m32r/kernel/head.o
 LIBGCC  := $(shell $(CC) $(KBUILD_CFLAGS) -print-libgcc-file-name)
diff --git a/arch/m32r/include/asm/thread_info.h b/arch/m32r/include/asm/thread_info.h
index bf8fa3c06f4e..c083f6073ef4 100644
--- a/arch/m32r/include/asm/thread_info.h
+++ b/arch/m32r/include/asm/thread_info.h
@@ -55,8 +55,8 @@ struct thread_info {
 #define PREEMPT_ACTIVE          0x10000000
-#define THREAD_SIZE (PAGE_SIZE << 1)
+#define THREAD_SIZE             (PAGE_SIZE << 1)
+#define THREAD_SIZE_ORDER       1
 /*
 * macros/functions for gaining access to the thread information structure
 */
@@ -92,19 +92,6 @@ static inline struct thread_info *current_thread_info(void)
        return ti;
 }
-#define __HAVE_ARCH_THREAD_INFO_ALLOCATOR
-/* thread information allocation */
-#ifdef CONFIG_DEBUG_STACK_USAGE
-#define alloc_thread_info_node(tsk, node)                       \
-                kzalloc_node(THREAD_SIZE, GFP_KERNEL, node)
-#else
-#define alloc_thread_info_node(tsk, node)                       \
-                kmalloc_node(THREAD_SIZE, GFP_KERNEL, node)
-#endif
-#define free_thread_info(info) kfree(info)
 #define TI_FLAG_FAULT_CODE_SHIFT        28
 static inline void set_thread_fault_code(unsigned int val)
diff --git a/arch/m32r/kernel/Makefile b/arch/m32r/kernel/Makefile
index b1a4b6036591..0c09dad8b1f8 100644
--- a/arch/m32r/kernel/Makefile
+++ b/arch/m32r/kernel/Makefile
@@ -2,7 +2,7 @@
 # Makefile for the Linux/M32R kernel.
 #
-extra-y := head.o init_task.o vmlinux.lds
+extra-y := head.o vmlinux.lds
 obj-y   := process.o entry.o traps.o align.o irq.o setup.o time.o \
        m32r_ksyms.o sys_m32r.o signal.o ptrace.o
diff --git a/arch/m32r/kernel/init_task.c b/arch/m32r/kernel/init_task.c
deleted file mode 100644
index 6c42d5f8df50..000000000000
--- a/arch/m32r/kernel/init_task.c
+++ /dev/null
@@ -1,34 +0,0 @@
-/* orig : i386 init_task.c */
-#include <linux/mm.h>
-#include <linux/module.h>
-#include <linux/sched.h>
-#include <linux/init.h>
-#include <linux/init_task.h>
-#include <linux/fs.h>
-#include <linux/mqueue.h>
-#include <asm/uaccess.h>
-#include <asm/pgtable.h>
-static struct signal_struct init_signals = INIT_SIGNALS(init_signals);
-static struct sighand_struct init_sighand = INIT_SIGHAND(init_sighand);
-/*
- * Initial thread structure.
- *
- * We need to make sure that this is 8192-byte aligned due to the
- * way process stacks are handled. This is done by having a special
- * "init_task" linker map entry..
- */
-union thread_union init_thread_union __init_task_data =
-        { INIT_THREAD_INFO(init_task) };
-/*
- * Initial task structure.
- *
- * All other task structs will be allocated on slabs in fork.c
- */
-struct task_struct init_task = INIT_TASK(init_task);
-EXPORT_SYMBOL(init_task);
diff --git a/arch/m32r/kernel/smpboot.c b/arch/m32r/kernel/smpboot.c
index cfdbe5d15002..a2cfc0abb05c 100644
--- a/arch/m32r/kernel/smpboot.c
+++ b/arch/m32r/kernel/smpboot.c
@@ -109,12 +109,8 @@ static unsigned int calibration_result;
 /* Function Prototypes                                                       */
 /*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*/
-void smp_prepare_boot_cpu(void);
-void smp_prepare_cpus(unsigned int);
 static void init_ipi_lock(void);
 static void do_boot_cpu(int);
-int __cpu_up(unsigned int);
-void smp_cpus_done(unsigned int);
 int start_secondary(void *);
 static void smp_callin(void);
@@ -347,7 +343,7 @@ static void __init do_boot_cpu(int phys_id)
        }
 }
-int __cpuinit __cpu_up(unsigned int cpu_id)
+int __cpuinit __cpu_up(unsigned int cpu_id, struct task_struct *tidle)
 {
        int timeout;
diff --git a/arch/m68k/kernel/Makefile b/arch/m68k/kernel/Makefile
index 40d29a788b05..5c7070e21eb7 100644
--- a/arch/m68k/kernel/Makefile
+++ b/arch/m68k/kernel/Makefile
@@ -13,7 +13,7 @@ extra-$(CONFIG_SUN3X)	:= head.o
 extra-$(CONFIG_SUN3)    := sun3-head.o
 extra-y                 += vmlinux.lds
-obj-y   := entry.o init_task.o irq.o m68k_ksyms.o module.o process.o ptrace.o
+obj-y   := entry.o irq.o m68k_ksyms.o module.o process.o ptrace.o
 obj-y   += setup.o signal.o sys_m68k.o syscalltable.o time.o traps.o
 obj-$(CONFIG_MMU_MOTOROLA) += ints.o vectors.o
diff --git a/arch/m68k/kernel/init_task.c b/arch/m68k/kernel/init_task.c
deleted file mode 100644
index c744cfc6bfa1..000000000000
--- a/arch/m68k/kernel/init_task.c
+++ /dev/null
@@ -1,35 +0,0 @@
-/*
- *  linux/arch/m68knommu/kernel/init_task.c
- */
-#include <linux/mm.h>
-#include <linux/module.h>
-#include <linux/sched.h>
-#include <linux/init.h>
-#include <linux/init_task.h>
-#include <linux/fs.h>
-#include <linux/mqueue.h>
-#include <asm/uaccess.h>
-#include <asm/pgtable.h>
-static struct signal_struct init_signals = INIT_SIGNALS(init_signals);
-static struct sighand_struct init_sighand = INIT_SIGHAND(init_sighand);
-/*
- * Initial task structure.
- *
- * All other task structs will be allocated on slabs in fork.c
- */
-struct task_struct init_task = INIT_TASK(init_task);
-EXPORT_SYMBOL(init_task);
-/*
- * Initial thread structure.
- *
- * We need to make sure that this is THREAD size aligned due to the
- * way process stacks are handled. This is done by having a special
- * "init_task" linker map entry..
- */
-union thread_union init_thread_union __init_task_data =
-        { INIT_THREAD_INFO(init_task) };
diff --git a/arch/microblaze/kernel/Makefile b/arch/microblaze/kernel/Makefile
index 494b63b72dd7..928c950fc14c 100644
--- a/arch/microblaze/kernel/Makefile
+++ b/arch/microblaze/kernel/Makefile
@@ -16,7 +16,7 @@ endif
 extra-y := head.o vmlinux.lds
 obj-y += dma.o exceptions.o \
-        hw_exception_handler.o init_task.o intc.o irq.o \
+        hw_exception_handler.o intc.o irq.o \
        process.o prom.o prom_parse.o ptrace.o \
        reset.o setup.o signal.o sys_microblaze.o timer.o traps.o unwind.o
diff --git a/arch/microblaze/kernel/init_task.c b/arch/microblaze/kernel/init_task.c
deleted file mode 100644
index b5d711f94ff8..000000000000
--- a/arch/microblaze/kernel/init_task.c
+++ /dev/null
@@ -1,26 +0,0 @@
-/*
- * Copyright (C) 2009 Michal Simek <monstr@monstr.eu>
- * Copyright (C) 2009 PetaLogix
- * Copyright (C) 2006 Atmark Techno, Inc.
- *
- * This file is subject to the terms and conditions of the GNU General Public
- * License. See the file "COPYING" in the main directory of this archive
- * for more details.
- */
-#include <linux/module.h>
-#include <linux/sched.h>
-#include <linux/init_task.h>
-#include <linux/fs.h>
-#include <linux/mqueue.h>
-#include <asm/pgtable.h>
-static struct signal_struct init_signals = INIT_SIGNALS(init_signals);
-static struct sighand_struct init_sighand = INIT_SIGHAND(init_sighand);
-union thread_union init_thread_union __init_task_data =
-        { INIT_THREAD_INFO(init_task) };
-struct task_struct init_task = INIT_TASK(init_task);
-EXPORT_SYMBOL(init_task);
diff --git a/arch/mips/Kconfig b/arch/mips/Kconfig
index ce30e2f91d77..186fc8cf9ee0 100644
--- a/arch/mips/Kconfig
+++ b/arch/mips/Kconfig
@@ -29,6 +29,7 @@ config MIPS
        select HAVE_MEMBLOCK
        select HAVE_MEMBLOCK_NODE_MAP
        select ARCH_DISCARD_MEMBLOCK
+        select GENERIC_SMP_IDLE_THREAD
 menu "Machine selection"
diff --git a/arch/mips/Makefile b/arch/mips/Makefile
index 4fedf5a51d96..76017c25a9e6 100644
--- a/arch/mips/Makefile
+++ b/arch/mips/Makefile
@@ -235,7 +235,7 @@ endif
 OBJCOPYFLAGS            += --remove-section=.reginfo
-head-y := arch/mips/kernel/head.o arch/mips/kernel/init_task.o
+head-y := arch/mips/kernel/head.o
 libs-y                  += arch/mips/lib/
diff --git a/arch/mips/include/asm/thread_info.h b/arch/mips/include/asm/thread_info.h
index 0d85d8e440c5..e2eca7d10598 100644
--- a/arch/mips/include/asm/thread_info.h
+++ b/arch/mips/include/asm/thread_info.h
@@ -85,18 +85,6 @@ register struct thread_info *__current_thread_info __asm__("$28");
 #define STACK_WARN      (THREAD_SIZE / 8)
-#define __HAVE_ARCH_THREAD_INFO_ALLOCATOR
-#ifdef CONFIG_DEBUG_STACK_USAGE
-#define alloc_thread_info_node(tsk, node) \
-                kzalloc_node(THREAD_SIZE, GFP_KERNEL, node)
-#else
-#define alloc_thread_info_node(tsk, node) \
-                kmalloc_node(THREAD_SIZE, GFP_KERNEL, node)
-#endif
-#define free_thread_info(info) kfree(info)
 #endif /* !__ASSEMBLY__ */
 #define PREEMPT_ACTIVE          0x10000000
diff --git a/arch/mips/kernel/Makefile b/arch/mips/kernel/Makefile
index 0c6877ea9004..fdaf65e1a99d 100644
--- a/arch/mips/kernel/Makefile
+++ b/arch/mips/kernel/Makefile
@@ -2,7 +2,7 @@
 # Makefile for the Linux/MIPS kernel.
 #
-extra-y         := head.o init_task.o vmlinux.lds
+extra-y         := head.o vmlinux.lds
 obj-y           += cpu-probe.o branch.o entry.o genex.o irq.o process.o \
                   ptrace.o reset.o setup.o signal.o syscall.o \
diff --git a/arch/mips/kernel/init_task.c b/arch/mips/kernel/init_task.c
deleted file mode 100644
index 5f9a76263c9a..000000000000
--- a/arch/mips/kernel/init_task.c
+++ /dev/null
@@ -1,35 +0,0 @@
-#include <linux/mm.h>
-#include <linux/export.h>
-#include <linux/sched.h>
-#include <linux/init_task.h>
-#include <linux/fs.h>
-#include <linux/mqueue.h>
-#include <asm/thread_info.h>
-#include <asm/uaccess.h>
-#include <asm/pgtable.h>
-static struct signal_struct init_signals = INIT_SIGNALS(init_signals);
-static struct sighand_struct init_sighand = INIT_SIGHAND(init_sighand);
-/*
- * Initial thread structure.
- *
- * We need to make sure that this is 8192-byte aligned due to the
- * way process stacks are handled. This is done by making sure
- * the linker maps this in the .text segment right after head.S,
- * and making head.S ensure the proper alignment.
- *
- * The things we do for performance..
- */
-union thread_union init_thread_union __init_task_data
-        __attribute__((__aligned__(THREAD_SIZE))) =
-                { INIT_THREAD_INFO(init_task) };
-/*
- * Initial task structure.
- *
- * All other task structs will be allocated on slabs in fork.c
- */
-struct task_struct init_task = INIT_TASK(init_task);
-EXPORT_SYMBOL(init_task);
diff --git a/arch/mips/kernel/smp.c b/arch/mips/kernel/smp.c
index ba9376bf52a1..71a95f55a649 100644
--- a/arch/mips/kernel/smp.c
+++ b/arch/mips/kernel/smp.c
@@ -186,61 +186,9 @@ void __devinit smp_prepare_boot_cpu(void)
        cpu_set(0, cpu_callin_map);
 }
-/*
+int __cpuinit __cpu_up(unsigned int cpu, struct task_struct *tidle)
- * Called once for each "cpu_possible(cpu)".  Needs to spin up the cpu
- * and keep control until "cpu_online(cpu)" is set.  Note: cpu is
- * physical, not logical.
- */
-static struct task_struct *cpu_idle_thread[NR_CPUS];
-struct create_idle {
-        struct work_struct work;
-        struct task_struct *idle;
-        struct completion done;
-        int cpu;
-};
-static void __cpuinit do_fork_idle(struct work_struct *work)
-{
-        struct create_idle *c_idle =
-                container_of(work, struct create_idle, work);
-        c_idle->idle = fork_idle(c_idle->cpu);
-        complete(&c_idle->done);
-}
-int __cpuinit __cpu_up(unsigned int cpu)
 {
-        struct task_struct *idle;
+        mp_ops->boot_secondary(cpu, tidle);
-        /*
-         * Processor goes to start_secondary(), sets online flag
-         * The following code is purely to make sure
-         * Linux can schedule processes on this slave.
-         */
-        if (!cpu_idle_thread[cpu]) {
-                /*
-                 * Schedule work item to avoid forking user task
-                 * Ported from arch/x86/kernel/smpboot.c
-                 */
-                struct create_idle c_idle = {
-                        .cpu    = cpu,
-                        .done   = COMPLETION_INITIALIZER_ONSTACK(c_idle.done),
-                };
-                INIT_WORK_ONSTACK(&c_idle.work, do_fork_idle);
-                schedule_work(&c_idle.work);
-                wait_for_completion(&c_idle.done);
-                idle = cpu_idle_thread[cpu] = c_idle.idle;
-                if (IS_ERR(idle))
-                        panic(KERN_ERR "Fork failed for CPU %d", cpu);
-        } else {
-                idle = cpu_idle_thread[cpu];
-                init_idle(idle, cpu);
-        }
-        mp_ops->boot_secondary(cpu, idle);
        /*
         * Trust is futile.  We should really have timeouts ...
diff --git a/arch/mn10300/Makefile b/arch/mn10300/Makefile
index 7120282bf0d8..33188b6e81e4 100644
--- a/arch/mn10300/Makefile
+++ b/arch/mn10300/Makefile
@@ -51,7 +51,7 @@ UNIT		:= asb2364
 endif
-head-y          := arch/mn10300/kernel/head.o arch/mn10300/kernel/init_task.o
+head-y          := arch/mn10300/kernel/head.o
 core-y          += arch/mn10300/kernel/ arch/mn10300/mm/
diff --git a/arch/mn10300/include/asm/thread_info.h b/arch/mn10300/include/asm/thread_info.h
index 28cf52100baa..08251d6f6b11 100644
--- a/arch/mn10300/include/asm/thread_info.h
+++ b/arch/mn10300/include/asm/thread_info.h
@@ -20,8 +20,10 @@
 #ifdef CONFIG_4KSTACKS
 #define THREAD_SIZE             (4096)
+#define THREAD_SIZE_ORDER       (0)
 #else
 #define THREAD_SIZE             (8192)
+#define THREAD_SIZE_ORDER       (1)
 #endif
 #define STACK_WARN              (THREAD_SIZE / 8)
@@ -120,21 +122,8 @@ static inline unsigned long current_stack_pointer(void)
        return sp;
 }
-#define __HAVE_ARCH_THREAD_INFO_ALLOCATOR
-/* thread information allocation */
-#ifdef CONFIG_DEBUG_STACK_USAGE
-#define alloc_thread_info_node(tsk, node)                       \
-                kzalloc_node(THREAD_SIZE, GFP_KERNEL, node)
-#else
-#define alloc_thread_info_node(tsk, node)                       \
-                kmalloc_node(THREAD_SIZE, GFP_KERNEL, node)
-#endif
 #ifndef CONFIG_KGDB
-#define free_thread_info(ti)    kfree((ti))
+void arch_release_thread_info(struct thread_info *ti)
-#else
-extern void free_thread_info(struct thread_info *);
 #endif
 #define get_thread_info(ti)     get_task_struct((ti)->task)
 #define put_thread_info(ti)     put_task_struct((ti)->task)
diff --git a/arch/mn10300/kernel/Makefile b/arch/mn10300/kernel/Makefile
index 47ed30fe8178..d06749173d63 100644
--- a/arch/mn10300/kernel/Makefile
+++ b/arch/mn10300/kernel/Makefile
@@ -1,7 +1,7 @@
 #
 # Makefile for the MN10300-specific core kernel code
 #
-extra-y := head.o init_task.o vmlinux.lds
+extra-y := head.o vmlinux.lds
 fpu-obj-y := fpu-nofpu.o fpu-nofpu-low.o
 fpu-obj-$(CONFIG_FPU) := fpu.o fpu-low.o
diff --git a/arch/mn10300/kernel/init_task.c b/arch/mn10300/kernel/init_task.c
deleted file mode 100644
index a481b043bea7..000000000000
--- a/arch/mn10300/kernel/init_task.c
+++ /dev/null
@@ -1,39 +0,0 @@
-/* MN10300 Initial task definitions
- *
- * Copyright (C) 2007 Matsushita Electric Industrial Co., Ltd.
- * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
- *
- * This program is free software; you can redistribute it and/or
- * modify it under the terms of the GNU General Public Licence
- * as published by the Free Software Foundation; either version
- * 2 of the Licence, or (at your option) any later version.
- */
-#include <linux/mm.h>
-#include <linux/module.h>
-#include <linux/sched.h>
-#include <linux/init.h>
-#include <linux/init_task.h>
-#include <linux/fs.h>
-#include <linux/mqueue.h>
-#include <asm/uaccess.h>
-#include <asm/pgtable.h>
-static struct signal_struct init_signals = INIT_SIGNALS(init_signals);
-static struct sighand_struct init_sighand = INIT_SIGHAND(init_sighand);
-/*
- * Initial thread structure.
- *
- * We need to make sure that this is THREAD_SIZE aligned due to the
- * way process stacks are handled. This is done by having a special
- * "init_task" linker map entry..
- */
-union thread_union init_thread_union __init_task_data =
-        { INIT_THREAD_INFO(init_task) };
-/*
- * Initial task structure.
- *
- * All other task structs will be allocated on slabs in fork.c
- */
-struct task_struct init_task = INIT_TASK(init_task);
-EXPORT_SYMBOL(init_task);
diff --git a/arch/mn10300/kernel/kgdb.c b/arch/mn10300/kernel/kgdb.c
index f6c981db2a36..99770823451a 100644
--- a/arch/mn10300/kernel/kgdb.c
+++ b/arch/mn10300/kernel/kgdb.c
@@ -397,7 +397,7 @@ static bool kgdb_arch_undo_singlestep(struct pt_regs *regs)
 * single-step state is cleared.  At this point the breakpoints should have
 * been removed by __switch_to().
 */
-void free_thread_info(struct thread_info *ti)
+void arch_release_thread_info(struct thread_info *ti)
 {
        if (kgdb_sstep_thread == ti) {
                kgdb_sstep_thread = NULL;
@@ -407,7 +407,6 @@ void free_thread_info(struct thread_info *ti)
                 * so force immediate reentry */
                kgdb_breakpoint();
        }
-        kfree(ti);
 }
 /*
diff --git a/arch/mn10300/kernel/smp.c b/arch/mn10300/kernel/smp.c
index 9cd69ad6aa02..090d35d36973 100644
--- a/arch/mn10300/kernel/smp.c
+++ b/arch/mn10300/kernel/smp.c
@@ -924,7 +924,7 @@ void initialize_secondary(void)
 * __cpu_up - Set smp_commenced_mask for the nominated CPU
 * @cpu: The target CPU.
 */
-int __devinit __cpu_up(unsigned int cpu)
+int __devinit __cpu_up(unsigned int cpu, struct task_struct *tidle)
 {
        int timeout;
diff --git a/arch/openrisc/Makefile b/arch/openrisc/Makefile
index 158ae4c0dc6c..966886c8daf5 100644
--- a/arch/openrisc/Makefile
+++ b/arch/openrisc/Makefile
@@ -38,7 +38,7 @@ else
        KBUILD_CFLAGS += $(call cc-option,-msoft-div)
 endif
-head-y          := arch/openrisc/kernel/head.o arch/openrisc/kernel/init_task.o
+head-y          := arch/openrisc/kernel/head.o
 core-y          += arch/openrisc/lib/ \
                   arch/openrisc/kernel/ \
diff --git a/arch/openrisc/kernel/Makefile b/arch/openrisc/kernel/Makefile
index 9a4c2706d795..e1ee0fa2bbda 100644
--- a/arch/openrisc/kernel/Makefile
+++ b/arch/openrisc/kernel/Makefile
@@ -2,7 +2,7 @@
 # Makefile for the linux kernel.
 #
-extra-y := head.o vmlinux.lds init_task.o
+extra-y := head.o vmlinux.lds
 obj-y   := setup.o idle.o or32_ksyms.o process.o dma.o \
           traps.o time.o irq.o entry.o ptrace.o signal.o sys_or32.o \
diff --git a/arch/openrisc/kernel/init_task.c b/arch/openrisc/kernel/init_task.c
deleted file mode 100644
index ca534082d5f3..000000000000
--- a/arch/openrisc/kernel/init_task.c
+++ /dev/null
@@ -1,42 +0,0 @@
-/*
- * OpenRISC init_task.c
- *
- * Linux architectural port borrowing liberally from similar works of
- * others.  All original copyrights apply as per the original source
- * declaration.
- *
- * Modifications for the OpenRISC architecture:
- * Copyright (C) 2003 Matjaz Breskvar <phoenix@bsemi.com>
- * Copyright (C) 2010-2011 Jonas Bonn <jonas@southpole.se>
- *
- *      This program is free software; you can redistribute it and/or
- *      modify it under the terms of the GNU General Public License
- *      as published by the Free Software Foundation; either version
- *      2 of the License, or (at your option) any later version.
- */
-#include <linux/init_task.h>
-#include <linux/mqueue.h>
-#include <linux/export.h>
-static struct signal_struct init_signals = INIT_SIGNALS(init_signals);
-static struct sighand_struct init_sighand = INIT_SIGHAND(init_sighand);
-/*
- * Initial thread structure.
- *
- * We need to make sure that this is THREAD_SIZE aligned due to the
- * way process stacks are handled. This is done by having a special
- * "init_task" linker map entry..
- */
-union thread_union init_thread_union __init_task_data = {
-        INIT_THREAD_INFO(init_task)
-};
-/*
- * Initial task structure.
- *
- * All other task structs will be allocated on slabs in fork.c
- */
-struct task_struct init_task = INIT_TASK(init_task);
-EXPORT_SYMBOL(init_task);
diff --git a/arch/parisc/Kconfig b/arch/parisc/Kconfig
index 242a1b7ac759..ddb8b24b823d 100644
--- a/arch/parisc/Kconfig
+++ b/arch/parisc/Kconfig
@@ -17,6 +17,7 @@ config PARISC
        select GENERIC_PCI_IOMAP
        select IRQ_PER_CPU
        select ARCH_HAVE_NMI_SAFE_CMPXCHG
+        select GENERIC_SMP_IDLE_THREAD
        help
          The PA-RISC microprocessor is designed by Hewlett-Packard and used
diff --git a/arch/parisc/Makefile b/arch/parisc/Makefile
index 19ab7b2ea1cd..dbc3850b1d0d 100644
--- a/arch/parisc/Makefile
+++ b/arch/parisc/Makefile
@@ -75,7 +75,7 @@ head-y			:= arch/parisc/kernel/head.o
 KBUILD_CFLAGS   += $(cflags-y)
-kernel-y                        := mm/ kernel/ math-emu/ kernel/init_task.o
+kernel-y                        := mm/ kernel/ math-emu/
 kernel-$(CONFIG_HPUX)           += hpux/
 core-y  += $(addprefix arch/parisc/, $(kernel-y))
diff --git a/arch/parisc/kernel/Makefile b/arch/parisc/kernel/Makefile
index 67db0722e6ca..66ee3f12df58 100644
--- a/arch/parisc/kernel/Makefile
+++ b/arch/parisc/kernel/Makefile
@@ -2,7 +2,7 @@
 # Makefile for arch/parisc/kernel
 #
-extra-y                 := init_task.o head.o vmlinux.lds
+extra-y                 := head.o vmlinux.lds
 obj-y           := cache.o pacache.o setup.o traps.o time.o irq.o \
                   pa7300lc.o syscall.o entry.o sys_parisc.o firmware.o \
diff --git a/arch/parisc/kernel/init_task.c b/arch/parisc/kernel/init_task.c
deleted file mode 100644
index 4a91e433416f..000000000000
--- a/arch/parisc/kernel/init_task.c
+++ /dev/null
@@ -1,70 +0,0 @@
-/* 
- *    Static declaration of "init" task data structure.
- *
- *    Copyright (C) 2000 Paul Bame <bame at parisc-linux.org>
- *    Copyright (C) 2000-2001 John Marvin <jsm at parisc-linux.org>
- *    Copyright (C) 2001 Helge Deller <deller @ parisc-linux.org>
- *    Copyright (C) 2002 Matthew Wilcox <willy with parisc-linux.org>
- *
- *
- *    This program is free software; you can redistribute it and/or modify
- *    it under the terms of the GNU General Public License as published by
- *    the Free Software Foundation; either version 2 of the License, or
- *    (at your option) any later version.
- *
- *    This program is distributed in the hope that it will be useful,
- *    but WITHOUT ANY WARRANTY; without even the implied warranty of
- *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- *    GNU General Public License for more details.
- *
- *    You should have received a copy of the GNU General Public License
- *    along with this program; if not, write to the Free Software
- *    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
- */
-#include <linux/mm.h>
-#include <linux/fs.h>
-#include <linux/module.h>
-#include <linux/sched.h>
-#include <linux/init.h>
-#include <linux/init_task.h>
-#include <linux/mqueue.h>
-#include <asm/uaccess.h>
-#include <asm/pgtable.h>
-#include <asm/pgalloc.h>
-static struct signal_struct init_signals = INIT_SIGNALS(init_signals);
-static struct sighand_struct init_sighand = INIT_SIGHAND(init_sighand);
-/*
- * Initial task structure.
- *
- * We need to make sure that this is 16384-byte aligned due to the
- * way process stacks are handled. This is done by having a special
- * "init_task" linker map entry..
- */
-union thread_union init_thread_union __init_task_data
-        __attribute__((aligned(128))) =
-                { INIT_THREAD_INFO(init_task) };
-#if PT_NLEVELS == 3
-/* NOTE: This layout exactly conforms to the hybrid L2/L3 page table layout
- * with the first pmd adjacent to the pgd and below it. gcc doesn't actually
- * guarantee that global objects will be laid out in memory in the same order 
- * as the order of declaration, so put these in different sections and use
- * the linker script to order them. */
-pmd_t pmd0[PTRS_PER_PMD] __attribute__ ((__section__ (".data..vm0.pmd"), aligned(PAGE_SIZE)));
-#endif
-pgd_t swapper_pg_dir[PTRS_PER_PGD] __attribute__ ((__section__ (".data..vm0.pgd"), aligned(PAGE_SIZE)));
-pte_t pg0[PT_INITIAL * PTRS_PER_PTE] __attribute__ ((__section__ (".data..vm0.pte"), aligned(PAGE_SIZE)));
-/*
- * Initial task structure.
- *
- * All other task structs will be allocated on slabs in fork.c
- */
-EXPORT_SYMBOL(init_task);
-__asm__(".data");
-struct task_struct init_task = INIT_TASK(init_task);
diff --git a/arch/parisc/kernel/smp.c b/arch/parisc/kernel/smp.c
index 4dc7b7942b4c..a47828d31fe6 100644
--- a/arch/parisc/kernel/smp.c
+++ b/arch/parisc/kernel/smp.c
@@ -340,26 +340,11 @@ void __init smp_callin(void)
 /*
 * Bring one cpu online.
 */
-int __cpuinit smp_boot_one_cpu(int cpuid)
+int __cpuinit smp_boot_one_cpu(int cpuid, struct task_struct *idle)
 {
        const struct cpuinfo_parisc *p = &per_cpu(cpu_data, cpuid);
-        struct task_struct *idle;
        long timeout;
-        /* 
-         * Create an idle task for this CPU.  Note the address wed* give 
-         * to kernel_thread is irrelevant -- it's going to start
-         * where OS_BOOT_RENDEVZ vector in SAL says to start.  But
-         * this gets all the other task-y sort of data structures set
-         * up like we wish.   We need to pull the just created idle task 
-         * off the run queue and stuff it into the init_tasks[] array.  
-         * Sheesh . . .
-         */
-        idle = fork_idle(cpuid);
-        if (IS_ERR(idle))
-                panic("SMP: fork failed for CPU:%d", cpuid);
        task_thread_info(idle)->cpu = cpuid;
        /* Let _start know what logical CPU we're booting
@@ -403,10 +388,6 @@ int __cpuinit smp_boot_one_cpu(int cpuid)
                udelay(100);
                barrier();
        }
-        put_task_struct(idle);
-        idle = NULL;
        printk(KERN_CRIT "SMP: CPU:%d is stuck.\n", cpuid);
        return -1;
@@ -455,10 +436,10 @@ void smp_cpus_done(unsigned int cpu_max)
 }
-int __cpuinit __cpu_up(unsigned int cpu)
+int __cpuinit __cpu_up(unsigned int cpu, struct task_struct *tidle)
 {
        if (cpu != 0 && cpu < parisc_max_cpus)
-                smp_boot_one_cpu(cpu);
+                smp_boot_one_cpu(cpu, tidle);
        return cpu_online(cpu) ? 0 : -ENOSYS;
 }
diff --git a/arch/parisc/mm/init.c b/arch/parisc/mm/init.c
index 82f364e209fc..3ac462de53a4 100644
--- a/arch/parisc/mm/init.c
+++ b/arch/parisc/mm/init.c
@@ -33,6 +33,18 @@
 extern int  data_start;
+#if PT_NLEVELS == 3
+/* NOTE: This layout exactly conforms to the hybrid L2/L3 page table layout
+ * with the first pmd adjacent to the pgd and below it. gcc doesn't actually
+ * guarantee that global objects will be laid out in memory in the same order
+ * as the order of declaration, so put these in different sections and use
+ * the linker script to order them. */
+pmd_t pmd0[PTRS_PER_PMD] __attribute__ ((__section__ (".data..vm0.pmd"), aligned(PAGE_SIZE)));
+#endif
+pgd_t swapper_pg_dir[PTRS_PER_PGD] __attribute__ ((__section__ (".data..vm0.pgd"), aligned(PAGE_SIZE)));
+pte_t pg0[PT_INITIAL * PTRS_PER_PTE] __attribute__ ((__section__ (".data..vm0.pte"), aligned(PAGE_SIZE)));
 #ifdef CONFIG_DISCONTIGMEM
 struct node_map_data node_data[MAX_NUMNODES] __read_mostly;
 unsigned char pfnnid_map[PFNNID_MAP_MAX] __read_mostly;
diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index 73ec03945717..8a01098eaaca 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -87,10 +87,6 @@ config ARCH_HAS_ILOG2_U64
        bool
        default y if 64BIT
-config ARCH_HAS_CPU_IDLE_WAIT
-        bool
-        default y
 config GENERIC_HWEIGHT
        bool
        default y
@@ -144,6 +140,7 @@ config PPC
        select HAVE_BPF_JIT if PPC64
        select HAVE_ARCH_JUMP_LABEL
        select ARCH_HAVE_NMI_SAFE_CMPXCHG
+        select GENERIC_SMP_IDLE_THREAD
 config EARLY_PRINTK
        bool
diff --git a/arch/powerpc/include/asm/processor.h b/arch/powerpc/include/asm/processor.h
index 8e2d0371fe1e..48a26d379222 100644
--- a/arch/powerpc/include/asm/processor.h
+++ b/arch/powerpc/include/asm/processor.h
@@ -386,7 +386,6 @@ extern unsigned long cpuidle_disable;
 enum idle_boot_override {IDLE_NO_OVERRIDE = 0, IDLE_POWERSAVE_OFF};
 extern int powersave_nap;       /* set if nap mode can be used in idle loop */
-void cpu_idle_wait(void);
 #ifdef CONFIG_PSERIES_IDLE
 extern void update_smt_snooze_delay(int snooze);
diff --git a/arch/powerpc/include/asm/thread_info.h b/arch/powerpc/include/asm/thread_info.h
index 4a741c7efd02..1a1bb00f061a 100644
--- a/arch/powerpc/include/asm/thread_info.h
+++ b/arch/powerpc/include/asm/thread_info.h
@@ -62,21 +62,8 @@ struct thread_info {
 #define init_thread_info        (init_thread_union.thread_info)
 #define init_stack              (init_thread_union.stack)
-/* thread information allocation */
-#if THREAD_SHIFT >= PAGE_SHIFT
 #define THREAD_SIZE_ORDER       (THREAD_SHIFT - PAGE_SHIFT)
-#else /* THREAD_SHIFT < PAGE_SHIFT */
-#define __HAVE_ARCH_THREAD_INFO_ALLOCATOR
-extern struct thread_info *alloc_thread_info_node(struct task_struct *tsk, int node);
-extern void free_thread_info(struct thread_info *ti);
-#endif /* THREAD_SHIFT < PAGE_SHIFT */
 /* how to get the thread information struct from C */
 static inline struct thread_info *current_thread_info(void)
 {
diff --git a/arch/powerpc/kernel/Makefile b/arch/powerpc/kernel/Makefile
index f5808a35688c..83afacd3ba7b 100644
--- a/arch/powerpc/kernel/Makefile
+++ b/arch/powerpc/kernel/Makefile
@@ -28,7 +28,7 @@ endif
 obj-y                           := cputable.o ptrace.o syscalls.o \
                                   irq.o align.o signal_32.o pmc.o vdso.o \
-                                   init_task.o process.o systbl.o idle.o \
+                                   process.o systbl.o idle.o \
                                   signal.o sysfs.o cacheinfo.o time.o \
                                   prom.o traps.o setup-common.o \
                                   udbg.o misc.o io.o dma.o \
diff --git a/arch/powerpc/kernel/idle.c b/arch/powerpc/kernel/idle.c
index 6d2209ac0c44..2099d9a879e8 100644
--- a/arch/powerpc/kernel/idle.c
+++ b/arch/powerpc/kernel/idle.c
@@ -113,29 +113,6 @@ void cpu_idle(void)
        }
 }
-/*
- * cpu_idle_wait - Used to ensure that all the CPUs come out of the old
- * idle loop and start using the new idle loop.
- * Required while changing idle handler on SMP systems.
- * Caller must have changed idle handler to the new value before the call.
- * This window may be larger on shared systems.
- */
-void cpu_idle_wait(void)
-{
-        int cpu;
-        smp_mb();
-        /* kick all the CPUs so that they exit out of old idle routine */
-        get_online_cpus();
-        for_each_online_cpu(cpu) {
-                if (cpu != smp_processor_id())
-                        smp_send_reschedule(cpu);
-        }
-        put_online_cpus();
-}
-EXPORT_SYMBOL_GPL(cpu_idle_wait);
 int powersave_nap;
 #ifdef CONFIG_SYSCTL
diff --git a/arch/powerpc/kernel/init_task.c b/arch/powerpc/kernel/init_task.c
deleted file mode 100644
index d076d465dbd1..000000000000
--- a/arch/powerpc/kernel/init_task.c
+++ /dev/null
@@ -1,29 +0,0 @@
-#include <linux/mm.h>
-#include <linux/export.h>
-#include <linux/sched.h>
-#include <linux/init.h>
-#include <linux/init_task.h>
-#include <linux/fs.h>
-#include <linux/mqueue.h>
-#include <asm/uaccess.h>
-static struct signal_struct init_signals = INIT_SIGNALS(init_signals);
-static struct sighand_struct init_sighand = INIT_SIGHAND(init_sighand);
-/*
- * Initial thread structure.
- *
- * We need to make sure that this is 16384-byte aligned due to the
- * way process stacks are handled. This is done by having a special
- * "init_task" linker map entry..
- */
-union thread_union init_thread_union __init_task_data =
-        { INIT_THREAD_INFO(init_task) };
-/*
- * Initial task structure.
- *
- * All other task structs will be allocated on slabs in fork.c
- */
-struct task_struct init_task = INIT_TASK(init_task);
-EXPORT_SYMBOL(init_task);
diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c
index 4937c9690090..aa05935b6947 100644
--- a/arch/powerpc/kernel/process.c
+++ b/arch/powerpc/kernel/process.c
@@ -1252,37 +1252,6 @@ void __ppc64_runlatch_off(void)
 }
 #endif /* CONFIG_PPC64 */
-#if THREAD_SHIFT < PAGE_SHIFT
-static struct kmem_cache *thread_info_cache;
-struct thread_info *alloc_thread_info_node(struct task_struct *tsk, int node)
-{
-        struct thread_info *ti;
-        ti = kmem_cache_alloc_node(thread_info_cache, GFP_KERNEL, node);
-        if (unlikely(ti == NULL))
-                return NULL;
-#ifdef CONFIG_DEBUG_STACK_USAGE
-        memset(ti, 0, THREAD_SIZE);
-#endif
-        return ti;
-}
-void free_thread_info(struct thread_info *ti)
-{
-        kmem_cache_free(thread_info_cache, ti);
-}
-void thread_info_cache_init(void)
-{
-        thread_info_cache = kmem_cache_create("thread_info", THREAD_SIZE,
-                                              THREAD_SIZE, 0, NULL);
-        BUG_ON(thread_info_cache == NULL);
-}
-#endif /* THREAD_SHIFT < PAGE_SHIFT */
 unsigned long arch_align_stack(unsigned long sp)
 {
        if (!(current->personality & ADDR_NO_RANDOMIZE) && randomize_va_space)
diff --git a/arch/powerpc/kernel/smp.c b/arch/powerpc/kernel/smp.c
index d9f94410fd7f..e4cb34322de4 100644
--- a/arch/powerpc/kernel/smp.c
+++ b/arch/powerpc/kernel/smp.c
@@ -57,27 +57,9 @@
 #define DBG(fmt...)
 #endif
-/* Store all idle threads, this can be reused instead of creating
-* a new thread. Also avoids complicated thread destroy functionality
-* for idle threads.
-*/
 #ifdef CONFIG_HOTPLUG_CPU
-/*
- * Needed only for CONFIG_HOTPLUG_CPU because __cpuinitdata is
- * removed after init for !CONFIG_HOTPLUG_CPU.
- */
-static DEFINE_PER_CPU(struct task_struct *, idle_thread_array);
-#define get_idle_for_cpu(x)      (per_cpu(idle_thread_array, x))
-#define set_idle_for_cpu(x, p)   (per_cpu(idle_thread_array, x) = (p))
 /* State of each CPU during hotplug phases */
 static DEFINE_PER_CPU(int, cpu_state) = { 0 };
-#else
-static struct task_struct *idle_thread_array[NR_CPUS] __cpuinitdata ;
-#define get_idle_for_cpu(x)      (idle_thread_array[(x)])
-#define set_idle_for_cpu(x, p)   (idle_thread_array[(x)] = (p))
 #endif
 struct thread_info *secondary_ti;
@@ -429,60 +411,19 @@ int generic_check_cpu_restart(unsigned int cpu)
 }
 #endif
-struct create_idle {
+static void cpu_idle_thread_init(unsigned int cpu, struct task_struct *idle)
-        struct work_struct work;
-        struct task_struct *idle;
-        struct completion done;
-        int cpu;
-};
-static void __cpuinit do_fork_idle(struct work_struct *work)
 {
-        struct create_idle *c_idle =
+        struct thread_info *ti = task_thread_info(idle);
-                container_of(work, struct create_idle, work);
-        c_idle->idle = fork_idle(c_idle->cpu);
-        complete(&c_idle->done);
-}
-static int __cpuinit create_idle(unsigned int cpu)
-{
-        struct thread_info *ti;
-        struct create_idle c_idle = {
-                .cpu    = cpu,
-                .done   = COMPLETION_INITIALIZER_ONSTACK(c_idle.done),
-        };
-        INIT_WORK_ONSTACK(&c_idle.work, do_fork_idle);
-        c_idle.idle = get_idle_for_cpu(cpu);
-        /* We can't use kernel_thread since we must avoid to
-         * reschedule the child. We use a workqueue because
-         * we want to fork from a kernel thread, not whatever
-         * userspace process happens to be trying to online us.
-         */
-        if (!c_idle.idle) {
-                schedule_work(&c_idle.work);
-                wait_for_completion(&c_idle.done);
-        } else
-                init_idle(c_idle.idle, cpu);
-        if (IS_ERR(c_idle.idle)) {              
-                pr_err("Failed fork for CPU %u: %li", cpu, PTR_ERR(c_idle.idle));
-                return PTR_ERR(c_idle.idle);
-        }
-        ti = task_thread_info(c_idle.idle);
 #ifdef CONFIG_PPC64
-        paca[cpu].__current = c_idle.idle;
+        paca[cpu].__current = idle;
        paca[cpu].kstack = (unsigned long)ti + THREAD_SIZE - STACK_FRAME_OVERHEAD;
 #endif
        ti->cpu = cpu;
-        current_set[cpu] = ti;
+        secondary_ti = current_set[cpu] = ti;
-        return 0;
 }
-int __cpuinit __cpu_up(unsigned int cpu)
+int __cpuinit __cpu_up(unsigned int cpu, struct task_struct *tidle)
 {
        int rc, c;
@@ -490,12 +431,7 @@ int __cpuinit __cpu_up(unsigned int cpu)
            (smp_ops->cpu_bootable && !smp_ops->cpu_bootable(cpu)))
                return -EINVAL;
-        /* Make sure we have an idle thread */
+        cpu_idle_thread_init(cpu, tidle);
-        rc = create_idle(cpu);
-        if (rc)
-                return rc;
-        secondary_ti = current_set[cpu];
        /* Make sure callin-map entry is 0 (can be leftover a CPU
         * hotplug
diff --git a/arch/s390/Kconfig b/arch/s390/Kconfig
index b42f2866594b..e16390c0bca8 100644
--- a/arch/s390/Kconfig
+++ b/arch/s390/Kconfig
@@ -122,6 +122,7 @@ config S390
        select ARCH_INLINE_WRITE_UNLOCK_BH
        select ARCH_INLINE_WRITE_UNLOCK_IRQ
        select ARCH_INLINE_WRITE_UNLOCK_IRQRESTORE
+        select GENERIC_SMP_IDLE_THREAD
 config SCHED_OMIT_FRAME_POINTER
        def_bool y
diff --git a/arch/s390/Makefile b/arch/s390/Makefile
index 0ad2f1e1ce9e..49e76e8b477d 100644
--- a/arch/s390/Makefile
+++ b/arch/s390/Makefile
@@ -91,7 +91,6 @@ OBJCOPYFLAGS	:= -O binary
 head-y          := arch/s390/kernel/head.o
 head-y          += arch/s390/kernel/$(if $(CONFIG_64BIT),head64.o,head31.o)
-head-y          += arch/s390/kernel/init_task.o
 # See arch/s390/Kbuild for content of core part of the kernel
 core-y          += arch/s390/
diff --git a/arch/s390/include/asm/smp.h b/arch/s390/include/asm/smp.h
index c77c6de6f6c0..0b6f586c1383 100644
--- a/arch/s390/include/asm/smp.h
+++ b/arch/s390/include/asm/smp.h
@@ -16,7 +16,7 @@
 extern struct mutex smp_cpu_state_mutex;
 extern struct save_area *zfcpdump_save_areas[NR_CPUS + 1];
-extern int __cpu_up(unsigned int cpu);
+extern int __cpu_up(unsigned int cpu, struct task_struct *tidle);
 extern void arch_send_call_function_single_ipi(int cpu);
 extern void arch_send_call_function_ipi_mask(const struct cpumask *mask);
diff --git a/arch/s390/kernel/Makefile b/arch/s390/kernel/Makefile
index 884b18afc864..9733b3f0eb6d 100644
--- a/arch/s390/kernel/Makefile
+++ b/arch/s390/kernel/Makefile
@@ -28,7 +28,7 @@ obj-y	:=  bitmap.o traps.o time.o process.o base.o early.o setup.o vtime.o \
 obj-y   += $(if $(CONFIG_64BIT),entry64.o,entry.o)
 obj-y   += $(if $(CONFIG_64BIT),reipl64.o,reipl.o)
-extra-y                         += head.o init_task.o vmlinux.lds
+extra-y                         += head.o vmlinux.lds
 extra-y                         += $(if $(CONFIG_64BIT),head64.o,head31.o)
 obj-$(CONFIG_MODULES)           += s390_ksyms.o module.o
diff --git a/arch/s390/kernel/init_task.c b/arch/s390/kernel/init_task.c
deleted file mode 100644
index 4d1c9fb0b540..000000000000
--- a/arch/s390/kernel/init_task.c
+++ /dev/null
@@ -1,38 +0,0 @@
-/*
- *  arch/s390/kernel/init_task.c
- *
- *  S390 version
- *
- *  Derived from "arch/i386/kernel/init_task.c"
- */
-#include <linux/mm.h>
-#include <linux/fs.h>
-#include <linux/module.h>
-#include <linux/sched.h>
-#include <linux/init_task.h>
-#include <linux/mqueue.h>
-#include <asm/uaccess.h>
-#include <asm/pgtable.h>
-static struct signal_struct init_signals = INIT_SIGNALS(init_signals);
-static struct sighand_struct init_sighand = INIT_SIGHAND(init_sighand);
-/*
- * Initial thread structure.
- *
- * We need to make sure that this is THREAD_SIZE aligned due to the
- * way process stacks are handled. This is done by having a special
- * "init_task" linker map entry..
- */
-union thread_union init_thread_union __init_task_data =
-        { INIT_THREAD_INFO(init_task) };
-/*
- * Initial task structure.
- *
- * All other task structs will be allocated on slabs in fork.c
- */
-struct task_struct init_task = INIT_TASK(init_task);
-EXPORT_SYMBOL(init_task);
diff --git a/arch/s390/kernel/smp.c b/arch/s390/kernel/smp.c
index e505458c6899..647ba9425893 100644
--- a/arch/s390/kernel/smp.c
+++ b/arch/s390/kernel/smp.c
@@ -85,7 +85,6 @@ enum {
 struct pcpu {
        struct cpu cpu;
-        struct task_struct *idle;       /* idle process for the cpu */
        struct _lowcore *lowcore;       /* lowcore page(s) for the cpu */
        unsigned long async_stack;      /* async stack for the cpu */
        unsigned long panic_stack;      /* panic stack for the cpu */
@@ -725,26 +724,9 @@ static void __cpuinit smp_start_secondary(void *cpuvoid)
        cpu_idle();
 }
-struct create_idle {
-        struct work_struct work;
-        struct task_struct *idle;
-        struct completion done;
-        int cpu;
-};
-static void __cpuinit smp_fork_idle(struct work_struct *work)
-{
-        struct create_idle *c_idle;
-        c_idle = container_of(work, struct create_idle, work);
-        c_idle->idle = fork_idle(c_idle->cpu);
-        complete(&c_idle->done);
-}
 /* Upping and downing of CPUs */
-int __cpuinit __cpu_up(unsigned int cpu)
+int __cpuinit __cpu_up(unsigned int cpu, struct task_struct *tidle)
 {
-        struct create_idle c_idle;
        struct pcpu *pcpu;
        int rc;
@@ -754,22 +736,12 @@ int __cpuinit __cpu_up(unsigned int cpu)
        if (pcpu_sigp_retry(pcpu, sigp_initial_cpu_reset, 0) !=
            sigp_order_code_accepted)
                return -EIO;
-        if (!pcpu->idle) {
-                c_idle.done = COMPLETION_INITIALIZER_ONSTACK(c_idle.done);
-                INIT_WORK_ONSTACK(&c_idle.work, smp_fork_idle);
-                c_idle.cpu = cpu;
-                schedule_work(&c_idle.work);
-                wait_for_completion(&c_idle.done);
-                if (IS_ERR(c_idle.idle))
-                        return PTR_ERR(c_idle.idle);
-                pcpu->idle = c_idle.idle;
-        }
-        init_idle(pcpu->idle, cpu);
        rc = pcpu_alloc_lowcore(pcpu, cpu);
        if (rc)
                return rc;
        pcpu_prepare_secondary(pcpu, cpu);
-        pcpu_attach_task(pcpu, pcpu->idle);
+        pcpu_attach_task(pcpu, tidle);
        pcpu_start_fn(pcpu, smp_start_secondary, NULL);
        while (!cpu_online(cpu))
                cpu_relax();
@@ -856,7 +828,6 @@ void __init smp_prepare_boot_cpu(void)
        struct pcpu *pcpu = pcpu_devices;
        boot_cpu_address = stap();
-        pcpu->idle = current;
        pcpu->state = CPU_STATE_CONFIGURED;
        pcpu->address = boot_cpu_address;
        pcpu->lowcore = (struct _lowcore *)(unsigned long) store_prefix();
diff --git a/arch/score/include/asm/thread_info.h b/arch/score/include/asm/thread_info.h
index 2205c62284db..a18006e97f1c 100644
--- a/arch/score/include/asm/thread_info.h
+++ b/arch/score/include/asm/thread_info.h
@@ -11,10 +11,9 @@
 #include <linux/const.h>
 /* thread information allocation */
-#define THREAD_SIZE_ORDER       (1)
+#define THREAD_SIZE_ORDER       (1)
-#define THREAD_SIZE             (PAGE_SIZE << THREAD_SIZE_ORDER)
+#define THREAD_SIZE             (PAGE_SIZE << THREAD_SIZE_ORDER)
-#define THREAD_MASK             (THREAD_SIZE - _AC(1,UL))
+#define THREAD_MASK             (THREAD_SIZE - _AC(1,UL))
-#define __HAVE_ARCH_THREAD_INFO_ALLOCATOR
 #ifndef __ASSEMBLY__
@@ -71,9 +70,6 @@ struct thread_info {
 register struct thread_info *__current_thread_info __asm__("r28");
 #define current_thread_info()   __current_thread_info
-#define alloc_thread_info_node(tsk, node) kmalloc_node(THREAD_SIZE, GFP_KERNEL, node)
-#define free_thread_info(info) kfree(info)
 #endif /* !__ASSEMBLY__ */
 #define PREEMPT_ACTIVE          0x10000000
diff --git a/arch/score/kernel/Makefile b/arch/score/kernel/Makefile
index f218673b5d3d..fb1802b3f542 100644
--- a/arch/score/kernel/Makefile
+++ b/arch/score/kernel/Makefile
@@ -4,7 +4,7 @@
 extra-y := head.o vmlinux.lds
-obj-y += entry.o init_task.o irq.o process.o ptrace.o \
+obj-y += entry.o irq.o process.o ptrace.o \
        setup.o signal.o sys_score.o time.o traps.o \
        sys_call_table.o
diff --git a/arch/score/kernel/init_task.c b/arch/score/kernel/init_task.c
deleted file mode 100644
index baa03ee217d1..000000000000
--- a/arch/score/kernel/init_task.c
+++ /dev/null
@@ -1,46 +0,0 @@
-/*
- * arch/score/kernel/init_task.c
- *
- * Score Processor version.
- *
- * Copyright (C) 2009 Sunplus Core Technology Co., Ltd.
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; either version 2 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, see the file COPYING, or write
- * to the Free Software Foundation, Inc.,
- * 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
- */
-#include <linux/init_task.h>
-#include <linux/mqueue.h>
-static struct signal_struct init_signals = INIT_SIGNALS(init_signals);
-static struct sighand_struct init_sighand = INIT_SIGHAND(init_sighand);
-/*
- * Initial thread structure.
- *
- * We need to make sure that this is THREAD_SIZE aligned due to the
- * way process stacks are handled. This is done by having a special
- * "init_task" linker map entry..
- */
-union thread_union init_thread_union __init_task_data =
-        { INIT_THREAD_INFO(init_task) };
-/*
- * Initial task structure.
- *
- * All other task structs will be allocated on slabs in fork.c
- */
-struct task_struct init_task = INIT_TASK(init_task);
-EXPORT_SYMBOL(init_task);
diff --git a/arch/sh/Kconfig b/arch/sh/Kconfig
index ff9e033ce626..04a8cb4700af 100644
--- a/arch/sh/Kconfig
+++ b/arch/sh/Kconfig
@@ -28,6 +28,7 @@ config SUPERH
        select RTC_LIB
        select GENERIC_ATOMIC64
        select GENERIC_IRQ_SHOW
+        select GENERIC_SMP_IDLE_THREAD
        help
          The SuperH is a RISC processor targeted for use in embedded systems
          and consumer electronics; it was also used in the Sega Dreamcast
@@ -152,9 +153,6 @@ config ARCH_NO_VIRT_TO_BUS
 config ARCH_HAS_DEFAULT_IDLE
        def_bool y
-config ARCH_HAS_CPU_IDLE_WAIT
-        def_bool y
 config NO_IOPORT
        def_bool !PCI
        depends on !SH_CAYMAN && !SH_SH4202_MICRODEV && !SH_SHMIN
diff --git a/arch/sh/Makefile b/arch/sh/Makefile
index 3fc0f413777c..e14a676a0c7d 100644
--- a/arch/sh/Makefile
+++ b/arch/sh/Makefile
@@ -124,7 +124,7 @@ endif
 export ld-bfd BITS
-head-y  := arch/sh/kernel/init_task.o arch/sh/kernel/head_$(BITS).o
+head-y  := arch/sh/kernel/head_$(BITS).o
 core-y                          += arch/sh/kernel/ arch/sh/mm/ arch/sh/boards/
 core-$(CONFIG_SH_FPU_EMU)       += arch/sh/math-emu/
diff --git a/arch/sh/include/asm/processor.h b/arch/sh/include/asm/processor.h
index a229c393826a..6dbc1be28a0f 100644
--- a/arch/sh/include/asm/processor.h
+++ b/arch/sh/include/asm/processor.h
@@ -85,10 +85,6 @@ struct sh_cpuinfo {
        struct tlb_info itlb;
        struct tlb_info dtlb;
-#ifdef CONFIG_SMP
-        struct task_struct *idle;
-#endif
        unsigned int phys_bits;
        unsigned long flags;
 } __attribute__ ((aligned(L1_CACHE_BYTES)));
@@ -102,7 +98,6 @@ extern struct sh_cpuinfo cpu_data[];
 #define cpu_relax()     barrier()
 void default_idle(void);
-void cpu_idle_wait(void);
 void stop_this_cpu(void *);
 /* Forward decl */
diff --git a/arch/sh/include/asm/thread_info.h b/arch/sh/include/asm/thread_info.h
index 20ee40af16e9..b6902061d4dc 100644
--- a/arch/sh/include/asm/thread_info.h
+++ b/arch/sh/include/asm/thread_info.h
@@ -88,22 +88,13 @@ static inline struct thread_info *current_thread_info(void)
        return ti;
 }
-/* thread information allocation */
-#if THREAD_SHIFT >= PAGE_SHIFT
 #define THREAD_SIZE_ORDER       (THREAD_SHIFT - PAGE_SHIFT)
-#endif
-extern struct thread_info *alloc_thread_info_node(struct task_struct *tsk, int node);
-extern void free_thread_info(struct thread_info *ti);
 extern void arch_task_cache_init(void);
-#define arch_task_cache_init arch_task_cache_init
 extern int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src);
+extern void arch_release_task_struct(struct task_struct *tsk);
 extern void init_thread_xstate(void);
-#define __HAVE_ARCH_THREAD_INFO_ALLOCATOR
 #endif /* __ASSEMBLY__ */
 /*
diff --git a/arch/sh/kernel/Makefile b/arch/sh/kernel/Makefile
index 77f7ae1d4647..88571ff8eeec 100644
--- a/arch/sh/kernel/Makefile
+++ b/arch/sh/kernel/Makefile
@@ -2,7 +2,7 @@
 # Makefile for the Linux/SuperH kernel.
 #
-extra-y := head_$(BITS).o init_task.o vmlinux.lds
+extra-y := head_$(BITS).o vmlinux.lds
 ifdef CONFIG_FUNCTION_TRACER
 # Do not profile debug and lowlevel utilities
diff --git a/arch/sh/kernel/idle.c b/arch/sh/kernel/idle.c
index ee226e20c20c..0c910163caa3 100644
--- a/arch/sh/kernel/idle.c
+++ b/arch/sh/kernel/idle.c
@@ -132,10 +132,6 @@ void __init select_idle_routine(void)
                pm_idle = poll_idle;
 }
-static void do_nothing(void *unused)
-{
-}
 void stop_this_cpu(void *unused)
 {
        local_irq_disable();
@@ -144,19 +140,3 @@ void stop_this_cpu(void *unused)
        for (;;)
                cpu_sleep();
 }
-/*
- * cpu_idle_wait - Used to ensure that all the CPUs discard old value of
- * pm_idle and update to new pm_idle value. Required while changing pm_idle
- * handler on SMP systems.
- *
- * Caller must have changed pm_idle to the new value before the call. Old
- * pm_idle value will not be used by any CPU after the return of this function.
- */
-void cpu_idle_wait(void)
-{
-        smp_mb();
-        /* kick all the CPUs so that they exit out of pm_idle */
-        smp_call_function(do_nothing, NULL, 1);
-}
-EXPORT_SYMBOL_GPL(cpu_idle_wait);
diff --git a/arch/sh/kernel/init_task.c b/arch/sh/kernel/init_task.c
deleted file mode 100644
index 11f2ea556a6b..000000000000
--- a/arch/sh/kernel/init_task.c
+++ /dev/null
@@ -1,30 +0,0 @@
-#include <linux/mm.h>
-#include <linux/module.h>
-#include <linux/sched.h>
-#include <linux/init_task.h>
-#include <linux/mqueue.h>
-#include <linux/fs.h>
-#include <asm/uaccess.h>
-#include <asm/pgtable.h>
-static struct signal_struct init_signals = INIT_SIGNALS(init_signals);
-static struct sighand_struct init_sighand = INIT_SIGHAND(init_sighand);
-struct pt_regs fake_swapper_regs;
-/*
- * Initial thread structure.
- *
- * We need to make sure that this is 8192-byte aligned due to the
- * way process stacks are handled. This is done by having a special
- * "init_task" linker map entry..
- */
-union thread_union init_thread_union __init_task_data =
-        { INIT_THREAD_INFO(init_task) };
-/*
- * Initial task structure.
- *
- * All other task structs will be allocated on slabs in fork.c
- */
-struct task_struct init_task = INIT_TASK(init_task);
-EXPORT_SYMBOL(init_task);
diff --git a/arch/sh/kernel/process.c b/arch/sh/kernel/process.c
index 325f98b1736d..f2621abdf01d 100644
--- a/arch/sh/kernel/process.c
+++ b/arch/sh/kernel/process.c
@@ -29,52 +29,10 @@ void free_thread_xstate(struct task_struct *tsk)
        }
 }
-#if THREAD_SHIFT < PAGE_SHIFT
+void arch_release_task_struct(struct task_struct *tsk)
-static struct kmem_cache *thread_info_cache;
-struct thread_info *alloc_thread_info_node(struct task_struct *tsk, int node)
-{
-        struct thread_info *ti;
-#ifdef CONFIG_DEBUG_STACK_USAGE
-        gfp_t mask = GFP_KERNEL | __GFP_ZERO;
-#else
-        gfp_t mask = GFP_KERNEL;
-#endif
-        ti = kmem_cache_alloc_node(thread_info_cache, mask, node);
-        return ti;
-}
-void free_thread_info(struct thread_info *ti)
-{
-        free_thread_xstate(ti->task);
-        kmem_cache_free(thread_info_cache, ti);
-}
-void thread_info_cache_init(void)
-{
-        thread_info_cache = kmem_cache_create("thread_info", THREAD_SIZE,
-                                              THREAD_SIZE, SLAB_PANIC, NULL);
-}
-#else
-struct thread_info *alloc_thread_info_node(struct task_struct *tsk, int node)
-{
-#ifdef CONFIG_DEBUG_STACK_USAGE
-        gfp_t mask = GFP_KERNEL | __GFP_ZERO;
-#else
-        gfp_t mask = GFP_KERNEL;
-#endif
-        struct page *page = alloc_pages_node(node, mask, THREAD_SIZE_ORDER);
-        return page ? page_address(page) : NULL;
-}
-void free_thread_info(struct thread_info *ti)
 {
-        free_thread_xstate(ti->task);
+        free_thread_xstate(tsk);
-        free_pages((unsigned long)ti, THREAD_SIZE_ORDER);
 }
-#endif /* THREAD_SHIFT < PAGE_SHIFT */
 void arch_task_cache_init(void)
 {
diff --git a/arch/sh/kernel/smp.c b/arch/sh/kernel/smp.c
index eaebdf6a5c77..b86e9ca79455 100644
--- a/arch/sh/kernel/smp.c
+++ b/arch/sh/kernel/smp.c
@@ -220,22 +220,10 @@ extern struct {
        void *thread_info;
 } stack_start;
-int __cpuinit __cpu_up(unsigned int cpu)
+int __cpuinit __cpu_up(unsigned int cpu, struct task_struct *tsk)
 {
-        struct task_struct *tsk;
        unsigned long timeout;
-        tsk = cpu_data[cpu].idle;
-        if (!tsk) {
-                tsk = fork_idle(cpu);
-                if (IS_ERR(tsk)) {
-                        pr_err("Failed forking idle task for cpu %d\n", cpu);
-                        return PTR_ERR(tsk);
-                }
-                cpu_data[cpu].idle = tsk;
-        }
        per_cpu(cpu_state, cpu) = CPU_UP_PREPARE;
        /* Fill in data in head.S for secondary cpus */
diff --git a/arch/sparc/Kconfig b/arch/sparc/Kconfig
index d176c03274c5..b2b9daf59051 100644
--- a/arch/sparc/Kconfig
+++ b/arch/sparc/Kconfig
@@ -31,11 +31,13 @@ config SPARC
        select GENERIC_PCI_IOMAP
        select HAVE_NMI_WATCHDOG if SPARC64
        select HAVE_BPF_JIT
+        select GENERIC_SMP_IDLE_THREAD
 config SPARC32
        def_bool !64BIT
        select GENERIC_ATOMIC64
        select CLZ_TAB
+        select ARCH_THREAD_INFO_ALLOCATOR
 config SPARC64
        def_bool 64BIT
diff --git a/arch/sparc/Makefile b/arch/sparc/Makefile
index b9a72e2b8acc..541b8b075c7d 100644
--- a/arch/sparc/Makefile
+++ b/arch/sparc/Makefile
@@ -50,7 +50,6 @@ endif
 endif
 head-y                 := arch/sparc/kernel/head_$(BITS).o
-head-y                 += arch/sparc/kernel/init_task.o
 # See arch/sparc/Kbuild for the core part of the kernel
 core-y                 += arch/sparc/
diff --git a/arch/sparc/include/asm/leon.h b/arch/sparc/include/asm/leon.h
index 24f802beffb9..07659124c140 100644
--- a/arch/sparc/include/asm/leon.h
+++ b/arch/sparc/include/asm/leon.h
@@ -270,6 +270,7 @@ struct leon2_cacheregs {
 #include <linux/interrupt.h>
 struct device_node;
+struct task_struct;
 extern unsigned int leon_build_device_irq(unsigned int real_irq,
                                           irq_flow_handler_t flow_handler,
                                           const char *name, int do_ack);
@@ -289,7 +290,7 @@ extern int leon_smp_nrcpus(void);
 extern void leon_clear_profile_irq(int cpu);
 extern void leon_smp_done(void);
 extern void leon_boot_cpus(void);
-extern int leon_boot_one_cpu(int i);
+extern int leon_boot_one_cpu(int i, struct task_struct *);
 void leon_init_smp(void);
 extern void cpu_idle(void);
 extern void init_IRQ(void);
@@ -325,7 +326,7 @@ extern int leon_ipi_irq;
 #define init_leon() do {} while (0)
 #define leon_smp_done() do {} while (0)
 #define leon_boot_cpus() do {} while (0)
-#define leon_boot_one_cpu(i) 1
+#define leon_boot_one_cpu(i, t) 1
 #define leon_init_smp() do {} while (0)
 #endif /* !defined(CONFIG_SPARC_LEON) */
diff --git a/arch/sparc/include/asm/thread_info_32.h b/arch/sparc/include/asm/thread_info_32.h
index cd0b2dc8fab9..21a38946541d 100644
--- a/arch/sparc/include/asm/thread_info_32.h
+++ b/arch/sparc/include/asm/thread_info_32.h
@@ -79,8 +79,6 @@ register struct thread_info *current_thread_info_reg asm("g6");
 */
 #define THREAD_INFO_ORDER  1
-#define __HAVE_ARCH_THREAD_INFO_ALLOCATOR
 struct thread_info * alloc_thread_info_node(struct task_struct *tsk, int node);
 void free_thread_info(struct thread_info *);
diff --git a/arch/sparc/include/asm/thread_info_64.h b/arch/sparc/include/asm/thread_info_64.h
index 01d057fe6a3f..7f0981b09451 100644
--- a/arch/sparc/include/asm/thread_info_64.h
+++ b/arch/sparc/include/asm/thread_info_64.h
@@ -138,32 +138,11 @@ register struct thread_info *current_thread_info_reg asm("g6");
 /* thread information allocation */
 #if PAGE_SHIFT == 13
-#define __THREAD_INFO_ORDER     1
+#define THREAD_SIZE_ORDER       1
 #else /* PAGE_SHIFT == 13 */
-#define __THREAD_INFO_ORDER     0
+#define THREAD_SIZE_ORDER       0
 #endif /* PAGE_SHIFT == 13 */
-#define __HAVE_ARCH_THREAD_INFO_ALLOCATOR
-#ifdef CONFIG_DEBUG_STACK_USAGE
-#define THREAD_FLAGS (GFP_KERNEL | __GFP_ZERO)
-#else
-#define THREAD_FLAGS (GFP_KERNEL)
-#endif
-#define alloc_thread_info_node(tsk, node)                               \
-({                                                                      \
-        struct page *page = alloc_pages_node(node, THREAD_FLAGS,        \
-                                             __THREAD_INFO_ORDER);      \
-        struct thread_info *ret;                                        \
-                                                                        \
-        ret = page ? page_address(page) : NULL;                         \
-        ret;                                                            \
-})
-#define free_thread_info(ti) \
-        free_pages((unsigned long)(ti),__THREAD_INFO_ORDER)
 #define __thread_flag_byte_ptr(ti)      \
        ((unsigned char *)(&((ti)->flags)))
 #define __cur_thread_flag_byte_ptr      __thread_flag_byte_ptr(current_thread_info())
diff --git a/arch/sparc/kernel/Makefile b/arch/sparc/kernel/Makefile
index c19dd022b9cb..72308f9b0096 100644
--- a/arch/sparc/kernel/Makefile
+++ b/arch/sparc/kernel/Makefile
@@ -6,7 +6,6 @@ asflags-y := -ansi
 ccflags-y := -Werror
 extra-y     := head_$(BITS).o
-extra-y     += init_task.o
 # Undefine sparc when processing vmlinux.lds - it is used
 # And teach CPP we are doing $(BITS) builds (for this case)
diff --git a/arch/sparc/kernel/init_task.c b/arch/sparc/kernel/init_task.c
deleted file mode 100644
index 35f141a9f506..000000000000
--- a/arch/sparc/kernel/init_task.c
+++ /dev/null
@@ -1,22 +0,0 @@
-#include <linux/mm.h>
-#include <linux/fs.h>
-#include <linux/module.h>
-#include <linux/sched.h>
-#include <linux/init_task.h>
-#include <linux/mqueue.h>
-#include <asm/pgtable.h>
-#include <asm/uaccess.h>
-static struct signal_struct init_signals = INIT_SIGNALS(init_signals);
-static struct sighand_struct init_sighand = INIT_SIGHAND(init_sighand);
-struct task_struct init_task = INIT_TASK(init_task);
-EXPORT_SYMBOL(init_task);
-/* .text section in head.S is aligned at 8k boundary and this gets linked
- * right after that so that the init_thread_union is aligned properly as well.
- * If this is not aligned on a 8k boundary, then you should change code
- * in etrap.S which assumes it.
- */
-union thread_union init_thread_union __init_task_data =
-        { INIT_THREAD_INFO(init_task) };
diff --git a/arch/sparc/kernel/leon_smp.c b/arch/sparc/kernel/leon_smp.c
index 29325bacba6f..a469090faf9f 100644
--- a/arch/sparc/kernel/leon_smp.c
+++ b/arch/sparc/kernel/leon_smp.c
@@ -203,16 +203,11 @@ void __init leon_boot_cpus(void)
 }
-int __cpuinit leon_boot_one_cpu(int i)
+int __cpuinit leon_boot_one_cpu(int i, struct task_struct *idle)
 {
-        struct task_struct *p;
        int timeout;
-        /* Cook up an idler for this guy. */
+        current_set[i] = task_thread_info(idle);
-        p = fork_idle(i);
-        current_set[i] = task_thread_info(p);
        /* See trampoline.S:leon_smp_cpu_startup for details...
         * Initialize the contexts table
diff --git a/arch/sparc/kernel/smp_32.c b/arch/sparc/kernel/smp_32.c
index 57713758079e..79db45e5134a 100644
--- a/arch/sparc/kernel/smp_32.c
+++ b/arch/sparc/kernel/smp_32.c
@@ -256,21 +256,21 @@ void __init smp_prepare_boot_cpu(void)
        set_cpu_possible(cpuid, true);
 }
-int __cpuinit __cpu_up(unsigned int cpu)
+int __cpuinit __cpu_up(unsigned int cpu, struct task_struct *tidle)
 {
-        extern int __cpuinit smp4m_boot_one_cpu(int);
+        extern int __cpuinit smp4m_boot_one_cpu(int, struct task_struct *);
-        extern int __cpuinit smp4d_boot_one_cpu(int);
+        extern int __cpuinit smp4d_boot_one_cpu(int, struct task_struct *);
        int ret=0;
        switch(sparc_cpu_model) {
        case sun4m:
-                ret = smp4m_boot_one_cpu(cpu);
+                ret = smp4m_boot_one_cpu(cpu, tidle);
                break;
        case sun4d:
-                ret = smp4d_boot_one_cpu(cpu);
+                ret = smp4d_boot_one_cpu(cpu, tidle);
                break;
        case sparc_leon:
-                ret = leon_boot_one_cpu(cpu);
+                ret = leon_boot_one_cpu(cpu, tidle);
                break;
        case sun4e:
                printk("SUN4E\n");
diff --git a/arch/sparc/kernel/smp_64.c b/arch/sparc/kernel/smp_64.c
index 3b1bd7c50164..f591598d92f6 100644
--- a/arch/sparc/kernel/smp_64.c
+++ b/arch/sparc/kernel/smp_64.c
@@ -343,21 +343,17 @@ extern unsigned long sparc64_cpu_startup;
 */
 static struct thread_info *cpu_new_thread = NULL;
-static int __cpuinit smp_boot_one_cpu(unsigned int cpu)
+static int __cpuinit smp_boot_one_cpu(unsigned int cpu, struct task_struct *idle)
 {
        unsigned long entry =
                (unsigned long)(&sparc64_cpu_startup);
        unsigned long cookie =
                (unsigned long)(&cpu_new_thread);
-        struct task_struct *p;
        void *descr = NULL;
        int timeout, ret;
-        p = fork_idle(cpu);
-        if (IS_ERR(p))
-                return PTR_ERR(p);
        callin_flag = 0;
-        cpu_new_thread = task_thread_info(p);
+        cpu_new_thread = task_thread_info(idle);
        if (tlb_type == hypervisor) {
 #if defined(CONFIG_SUN_LDOMS) && defined(CONFIG_HOTPLUG_CPU)
@@ -1227,9 +1223,9 @@ void __devinit smp_fill_in_sib_core_maps(void)
        }
 }
-int __cpuinit __cpu_up(unsigned int cpu)
+int __cpuinit __cpu_up(unsigned int cpu, struct task_struct *tidle)
 {
-        int ret = smp_boot_one_cpu(cpu);
+        int ret = smp_boot_one_cpu(cpu, tidle);
        if (!ret) {
                cpumask_set_cpu(cpu, &smp_commenced_mask);
diff --git a/arch/sparc/kernel/sun4d_smp.c b/arch/sparc/kernel/sun4d_smp.c
index f9a1a33cbb2c..ddaea31de586 100644
--- a/arch/sparc/kernel/sun4d_smp.c
+++ b/arch/sparc/kernel/sun4d_smp.c
@@ -129,18 +129,14 @@ void __init smp4d_boot_cpus(void)
        local_ops->cache_all();
 }
-int __cpuinit smp4d_boot_one_cpu(int i)
+int __cpuinit smp4d_boot_one_cpu(int i, struct task_struct *idle)
 {
        unsigned long *entry = &sun4d_cpu_startup;
-        struct task_struct *p;
        int timeout;
        int cpu_node;
        cpu_find_by_instance(i, &cpu_node, NULL);
-        /* Cook up an idler for this guy. */
+        current_set[i] = task_thread_info(idle);
-        p = fork_idle(i);
-        current_set[i] = task_thread_info(p);
        /*
         * Initialize the contexts table
         * Since the call to prom_startcpu() trashes the structure,
diff --git a/arch/sparc/kernel/sun4m_smp.c b/arch/sparc/kernel/sun4m_smp.c
index 960e8ab47b12..128af7304288 100644
--- a/arch/sparc/kernel/sun4m_smp.c
+++ b/arch/sparc/kernel/sun4m_smp.c
@@ -90,18 +90,15 @@ void __init smp4m_boot_cpus(void)
        local_ops->cache_all();
 }
-int __cpuinit smp4m_boot_one_cpu(int i)
+int __cpuinit smp4m_boot_one_cpu(int i, struct task_struct *idle)
 {
        unsigned long *entry = &sun4m_cpu_startup;
-        struct task_struct *p;
        int timeout;
        int cpu_node;
        cpu_find_by_mid(i, &cpu_node);
+        current_set[i] = task_thread_info(idle);
-        /* Cook up an idler for this guy. */
-        p = fork_idle(i);
-        current_set[i] = task_thread_info(p);
        /* See trampoline.S for details... */
        entry += ((i - 1) * 3);
diff --git a/arch/tile/include/asm/thread_info.h b/arch/tile/include/asm/thread_info.h
index 7594764d8a69..656c486e64fa 100644
--- a/arch/tile/include/asm/thread_info.h
+++ b/arch/tile/include/asm/thread_info.h
@@ -77,16 +77,14 @@ struct thread_info {
 #ifndef __ASSEMBLY__
+void arch_release_thread_info(struct thread_info *info);
 /* How to get the thread information struct from C. */
 register unsigned long stack_pointer __asm__("sp");
 #define current_thread_info() \
  ((struct thread_info *)(stack_pointer & -THREAD_SIZE))
-#define __HAVE_ARCH_THREAD_INFO_ALLOCATOR
-extern struct thread_info *alloc_thread_info_node(struct task_struct *task, int node);
-extern void free_thread_info(struct thread_info *info);
 /* Sit on a nap instruction until interrupted. */
 extern void smp_nap(void);
diff --git a/arch/tile/kernel/Makefile b/arch/tile/kernel/Makefile
index b4dbc057baad..0d826faf8f35 100644
--- a/arch/tile/kernel/Makefile
+++ b/arch/tile/kernel/Makefile
@@ -3,7 +3,7 @@
 #
 extra-y := vmlinux.lds head_$(BITS).o
-obj-y := backtrace.o entry.o init_task.o irq.o messaging.o \
+obj-y := backtrace.o entry.o irq.o messaging.o \
        pci-dma.o proc.o process.o ptrace.o reboot.o \
        setup.o signal.o single_step.o stack.o sys.o sysfs.o time.o traps.o \
        intvec_$(BITS).o regs_$(BITS).o tile-desc_$(BITS).o
diff --git a/arch/tile/kernel/init_task.c b/arch/tile/kernel/init_task.c
deleted file mode 100644
index 928b31870669..000000000000
--- a/arch/tile/kernel/init_task.c
+++ /dev/null
@@ -1,59 +0,0 @@
-/*
- * Copyright 2010 Tilera Corporation. All Rights Reserved.
- *
- *   This program is free software; you can redistribute it and/or
- *   modify it under the terms of the GNU General Public License
- *   as published by the Free Software Foundation, version 2.
- *
- *   This program is distributed in the hope that it will be useful, but
- *   WITHOUT ANY WARRANTY; without even the implied warranty of
- *   MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
- *   NON INFRINGEMENT.  See the GNU General Public License for
- *   more details.
- */
-#include <linux/mm.h>
-#include <linux/fs.h>
-#include <linux/init_task.h>
-#include <linux/mqueue.h>
-#include <linux/module.h>
-#include <linux/start_kernel.h>
-#include <linux/uaccess.h>
-static struct signal_struct init_signals = INIT_SIGNALS(init_signals);
-static struct sighand_struct init_sighand = INIT_SIGHAND(init_sighand);
-/*
- * Initial thread structure.
- *
- * We need to make sure that this is THREAD_SIZE aligned due to the
- * way process stacks are handled. This is done by having a special
- * "init_task" linker map entry..
- */
-union thread_union init_thread_union __init_task_data = {
-        INIT_THREAD_INFO(init_task)
-};
-/*
- * Initial task structure.
- *
- * All other task structs will be allocated on slabs in fork.c
- */
-struct task_struct init_task = INIT_TASK(init_task);
-EXPORT_SYMBOL(init_task);
-/*
- * per-CPU stack and boot info.
- */
-DEFINE_PER_CPU(unsigned long, boot_sp) =
-        (unsigned long)init_stack + THREAD_SIZE;
-#ifdef CONFIG_SMP
-DEFINE_PER_CPU(unsigned long, boot_pc) = (unsigned long)start_kernel;
-#else
-/*
- * The variable must be __initdata since it references __init code.
- * With CONFIG_SMP it is per-cpu data, which is exempt from validation.
- */
-unsigned long __initdata boot_pc = (unsigned long)start_kernel;
-#endif
diff --git a/arch/tile/kernel/process.c b/arch/tile/kernel/process.c
index 54e6c64b85cc..f572c19c4082 100644
--- a/arch/tile/kernel/process.c
+++ b/arch/tile/kernel/process.c
@@ -114,27 +114,10 @@ void cpu_idle(void)
        }
 }
-struct thread_info *alloc_thread_info_node(struct task_struct *task, int node)
-{
-        struct page *page;
-        gfp_t flags = GFP_KERNEL;
-#ifdef CONFIG_DEBUG_STACK_USAGE
-        flags |= __GFP_ZERO;
-#endif
-        page = alloc_pages_node(node, flags, THREAD_SIZE_ORDER);
-        if (!page)
-                return NULL;
-        return (struct thread_info *)page_address(page);
-}
 /*
- * Free a thread_info node, and all of its derivative
+ * Release a thread_info structure
- * data structures.
 */
-void free_thread_info(struct thread_info *info)
+void arch_release_thread_info(struct thread_info *info)
 {
        struct single_step_state *step_state = info->step_state;
@@ -169,8 +152,6 @@ void free_thread_info(struct thread_info *info)
                 */
                kfree(step_state);
        }
-        free_pages((unsigned long)info, THREAD_SIZE_ORDER);
 }
 static void save_arch_state(struct thread_struct *t);
diff --git a/arch/tile/kernel/setup.c b/arch/tile/kernel/setup.c
index bff23f476110..98d80eb49ddb 100644
--- a/arch/tile/kernel/setup.c
+++ b/arch/tile/kernel/setup.c
@@ -61,6 +61,22 @@ unsigned long __initdata node_free_pfn[MAX_NUMNODES];
 static unsigned long __initdata node_percpu[MAX_NUMNODES];
+/*
+ * per-CPU stack and boot info.
+ */
+DEFINE_PER_CPU(unsigned long, boot_sp) =
+        (unsigned long)init_stack + THREAD_SIZE;
+#ifdef CONFIG_SMP
+DEFINE_PER_CPU(unsigned long, boot_pc) = (unsigned long)start_kernel;
+#else
+/*
+ * The variable must be __initdata since it references __init code.
+ * With CONFIG_SMP it is per-cpu data, which is exempt from validation.
+ */
+unsigned long __initdata boot_pc = (unsigned long)start_kernel;
+#endif
 #ifdef CONFIG_HIGHMEM
 /* Page frame index of end of lowmem on each controller. */
 unsigned long __cpuinitdata node_lowmem_end_pfn[MAX_NUMNODES];
diff --git a/arch/tile/kernel/smpboot.c b/arch/tile/kernel/smpboot.c
index 172aef7d3159..84873fbe8f27 100644
--- a/arch/tile/kernel/smpboot.c
+++ b/arch/tile/kernel/smpboot.c
@@ -222,7 +222,7 @@ void __cpuinit online_secondary(void)
        cpu_idle();
 }
-int __cpuinit __cpu_up(unsigned int cpu)
+int __cpuinit __cpu_up(unsigned int cpu, struct task_struct *tidle)
 {
        /* Wait 5s total for all CPUs for them to come online */
        static int timeout;
diff --git a/arch/um/include/asm/processor-generic.h b/arch/um/include/asm/processor-generic.h
index 98d01bc4fa92..7827394a5b6c 100644
--- a/arch/um/include/asm/processor-generic.h
+++ b/arch/um/include/asm/processor-generic.h
@@ -68,8 +68,6 @@ struct thread_struct {
        .request                = { 0 } \
 }
-extern struct task_struct *alloc_task_struct_node(int node);
 static inline void release_thread(struct task_struct *task)
 {
 }
diff --git a/arch/um/kernel/Makefile b/arch/um/kernel/Makefile
index 65a1c3d690ea..babe21826e3e 100644
--- a/arch/um/kernel/Makefile
+++ b/arch/um/kernel/Makefile
@@ -10,7 +10,7 @@ CPPFLAGS_vmlinux.lds := -DSTART=$(LDS_START)		\
 extra-y := vmlinux.lds
 clean-files :=
-obj-y = config.o exec.o exitcode.o init_task.o irq.o ksyms.o mem.o \
+obj-y = config.o exec.o exitcode.o irq.o ksyms.o mem.o \
        physmem.o process.o ptrace.o reboot.o sigio.o \
        signal.o smp.o syscall.o sysrq.o time.o tlb.o trap.o \
        um_arch.o umid.o skas/
diff --git a/arch/um/kernel/init_task.c b/arch/um/kernel/init_task.c
deleted file mode 100644
index ddc9698b66ed..000000000000
--- a/arch/um/kernel/init_task.c
+++ /dev/null
@@ -1,38 +0,0 @@
-/*
- * Copyright (C) 2000 - 2007 Jeff Dike (jdike@{addtoit,intel.linux}.com)
- * Licensed under the GPL
- */
-#include "linux/sched.h"
-#include "linux/init_task.h"
-#include "linux/fs.h"
-#include "linux/module.h"
-#include "linux/mqueue.h"
-#include "asm/uaccess.h"
-static struct signal_struct init_signals = INIT_SIGNALS(init_signals);
-static struct sighand_struct init_sighand = INIT_SIGHAND(init_sighand);
-/*
- * Initial task structure.
- *
- * All other task structs will be allocated on slabs in fork.c
- */
-struct task_struct init_task = INIT_TASK(init_task);
-EXPORT_SYMBOL(init_task);
-/*
- * Initial thread structure.
- *
- * We need to make sure that this is aligned due to the
- * way process stacks are handled. This is done by having a special
- * "init_task" linker map entry..
- */
-union thread_union init_thread_union __init_task_data =
-        { INIT_THREAD_INFO(init_task) };
-union thread_union cpu0_irqstack
-        __attribute__((__section__(".data..init_irqstack"))) =
-                { INIT_THREAD_INFO(init_task) };
diff --git a/arch/um/kernel/smp.c b/arch/um/kernel/smp.c
index 6f588e160fb0..a02b7e9e6b94 100644
--- a/arch/um/kernel/smp.c
+++ b/arch/um/kernel/smp.c
@@ -140,7 +140,7 @@ void smp_prepare_boot_cpu(void)
        set_cpu_online(smp_processor_id(), true);
 }
-int __cpu_up(unsigned int cpu)
+int __cpu_up(unsigned int cpu, struct task_struct *tidle)
 {
        cpu_set(cpu, smp_commenced_mask);
        while (!cpu_online(cpu))
diff --git a/arch/um/kernel/um_arch.c b/arch/um/kernel/um_arch.c
index ba00eae45aad..4db8770906ca 100644
--- a/arch/um/kernel/um_arch.c
+++ b/arch/um/kernel/um_arch.c
@@ -10,6 +10,7 @@
 #include <linux/seq_file.h>
 #include <linux/string.h>
 #include <linux/utsname.h>
+#include <linux/sched.h>
 #include <asm/pgtable.h>
 #include <asm/processor.h>
 #include <asm/setup.h>
@@ -47,6 +48,10 @@ struct cpuinfo_um boot_cpu_data = {
        .ipi_pipe               = { -1, -1 }
 };
+union thread_union cpu0_irqstack
+        __attribute__((__section__(".data..init_irqstack"))) =
+                { INIT_THREAD_INFO(init_task) };
 unsigned long thread_saved_pc(struct task_struct *task)
 {
        /* FIXME: Need to look up userspace_pid by cpu */
diff --git a/arch/unicore32/Makefile b/arch/unicore32/Makefile
index 6af4bc415f2b..b6f5c4c1eaf9 100644
--- a/arch/unicore32/Makefile
+++ b/arch/unicore32/Makefile
@@ -33,7 +33,6 @@ endif
 CHECKFLAGS              += -D__unicore32__
 head-y                  := arch/unicore32/kernel/head.o
-head-y                  += arch/unicore32/kernel/init_task.o
 core-y                  += arch/unicore32/kernel/
 core-y                  += arch/unicore32/mm/
diff --git a/arch/unicore32/kernel/Makefile b/arch/unicore32/kernel/Makefile
index aeb0f181568e..324010156958 100644
--- a/arch/unicore32/kernel/Makefile
+++ b/arch/unicore32/kernel/Makefile
@@ -29,4 +29,4 @@ obj-$(CONFIG_PUV3_NB0916)	+= puv3-nb0916.o
 head-y                          := head.o
 obj-$(CONFIG_DEBUG_LL)          += debug.o
-extra-y                         := $(head-y) init_task.o vmlinux.lds
+extra-y                         := $(head-y) vmlinux.lds
diff --git a/arch/unicore32/kernel/init_task.c b/arch/unicore32/kernel/init_task.c
deleted file mode 100644
index a35a1e50e4f4..000000000000
--- a/arch/unicore32/kernel/init_task.c
+++ /dev/null
@@ -1,44 +0,0 @@
-/*
- * linux/arch/unicore32/kernel/init_task.c
- *
- * Code specific to PKUnity SoC and UniCore ISA
- *
- * Copyright (C) 2001-2010 GUAN Xue-tao
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License version 2 as
- * published by the Free Software Foundation.
- */
-#include <linux/mm.h>
-#include <linux/module.h>
-#include <linux/fs.h>
-#include <linux/sched.h>
-#include <linux/init.h>
-#include <linux/init_task.h>
-#include <linux/mqueue.h>
-#include <linux/uaccess.h>
-#include <asm/pgtable.h>
-static struct signal_struct init_signals = INIT_SIGNALS(init_signals);
-static struct sighand_struct init_sighand = INIT_SIGHAND(init_sighand);
-/*
- * Initial thread structure.
- *
- * We need to make sure that this is 8192-byte aligned due to the
- * way process stacks are handled. This is done by making sure
- * the linker maps this in the .text segment right after head.S,
- * and making head.S ensure the proper alignment.
- *
- * The things we do for performance..
- */
-union thread_union init_thread_union __init_task_data = {
-        INIT_THREAD_INFO(init_task) };
-/*
- * Initial task structure.
- *
- * All other task structs will be allocated on slabs in fork.c
- */
-struct task_struct init_task = INIT_TASK(init_task);
-EXPORT_SYMBOL(init_task);
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 25f87bccbf8f..c940cb6f0409 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -82,6 +82,7 @@ config X86
        select ARCH_HAVE_NMI_SAFE_CMPXCHG
        select GENERIC_IOMAP
        select DCACHE_WORD_ACCESS
+        select GENERIC_SMP_IDLE_THREAD
 config INSTRUCTION_DECODER
        def_bool (KPROBES || PERF_EVENTS)
@@ -160,9 +161,6 @@ config RWSEM_GENERIC_SPINLOCK
 config RWSEM_XCHGADD_ALGORITHM
        def_bool X86_XADD
-config ARCH_HAS_CPU_IDLE_WAIT
-        def_bool y
 config GENERIC_CALIBRATE_DELAY
        def_bool y
diff --git a/arch/x86/Makefile b/arch/x86/Makefile
index 94e91e401da9..277418ff8b52 100644
--- a/arch/x86/Makefile
+++ b/arch/x86/Makefile
@@ -149,7 +149,6 @@ archheaders:
 head-y := arch/x86/kernel/head_$(BITS).o
 head-y += arch/x86/kernel/head$(BITS).o
 head-y += arch/x86/kernel/head.o
-head-y += arch/x86/kernel/init_task.o
 libs-y  += arch/x86/lib/
diff --git a/arch/x86/include/asm/boot.h b/arch/x86/include/asm/boot.h
index 5e1a2eef3e7c..b13fe63bdc59 100644
--- a/arch/x86/include/asm/boot.h
+++ b/arch/x86/include/asm/boot.h
@@ -19,7 +19,7 @@
 #ifdef CONFIG_X86_64
 #define MIN_KERNEL_ALIGN_LG2    PMD_SHIFT
 #else
-#define MIN_KERNEL_ALIGN_LG2    (PAGE_SHIFT + THREAD_ORDER)
+#define MIN_KERNEL_ALIGN_LG2    (PAGE_SHIFT + THREAD_SIZE_ORDER)
 #endif
 #define MIN_KERNEL_ALIGN        (_AC(1, UL) << MIN_KERNEL_ALIGN_LG2)
diff --git a/arch/x86/include/asm/page_32_types.h b/arch/x86/include/asm/page_32_types.h
index ade619ff9e2a..ef17af013475 100644
--- a/arch/x86/include/asm/page_32_types.h
+++ b/arch/x86/include/asm/page_32_types.h
@@ -15,8 +15,8 @@
 */
 #define __PAGE_OFFSET           _AC(CONFIG_PAGE_OFFSET, UL)
-#define THREAD_ORDER    1
+#define THREAD_SIZE_ORDER       1
-#define THREAD_SIZE     (PAGE_SIZE << THREAD_ORDER)
+#define THREAD_SIZE             (PAGE_SIZE << THREAD_SIZE_ORDER)
 #define STACKFAULT_STACK 0
 #define DOUBLEFAULT_STACK 1
diff --git a/arch/x86/include/asm/page_64_types.h b/arch/x86/include/asm/page_64_types.h
index 7639dbf5d223..320f7bb95f76 100644
--- a/arch/x86/include/asm/page_64_types.h
+++ b/arch/x86/include/asm/page_64_types.h
@@ -1,8 +1,8 @@
 #ifndef _ASM_X86_PAGE_64_DEFS_H
 #define _ASM_X86_PAGE_64_DEFS_H
-#define THREAD_ORDER    1
+#define THREAD_SIZE_ORDER       1
-#define THREAD_SIZE  (PAGE_SIZE << THREAD_ORDER)
+#define THREAD_SIZE  (PAGE_SIZE << THREAD_SIZE_ORDER)
 #define CURRENT_MASK (~(THREAD_SIZE - 1))
 #define EXCEPTION_STACK_ORDER 0
diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h
index 4fa7dcceb6c0..ccbb1ea99ccb 100644
--- a/arch/x86/include/asm/processor.h
+++ b/arch/x86/include/asm/processor.h
@@ -974,8 +974,6 @@ extern bool cpu_has_amd_erratum(const int *);
 #define cpu_has_amd_erratum(x)  (false)
 #endif /* CONFIG_CPU_SUP_AMD */
-void cpu_idle_wait(void);
 extern unsigned long arch_align_stack(unsigned long sp);
 extern void free_init_pages(char *what, unsigned long begin, unsigned long end);
diff --git a/arch/x86/include/asm/smp.h b/arch/x86/include/asm/smp.h
index 0434c400287c..f8cbc6f20e31 100644
--- a/arch/x86/include/asm/smp.h
+++ b/arch/x86/include/asm/smp.h
@@ -62,6 +62,8 @@ DECLARE_EARLY_PER_CPU(int, x86_cpu_to_logical_apicid);
 /* Static state in head.S used to set up a CPU */
 extern unsigned long stack_start; /* Initial stack pointer address */
+struct task_struct;
 struct smp_ops {
        void (*smp_prepare_boot_cpu)(void);
        void (*smp_prepare_cpus)(unsigned max_cpus);
@@ -70,7 +72,7 @@ struct smp_ops {
        void (*stop_other_cpus)(int wait);
        void (*smp_send_reschedule)(int cpu);
-        int (*cpu_up)(unsigned cpu);
+        int (*cpu_up)(unsigned cpu, struct task_struct *tidle);
        int (*cpu_disable)(void);
        void (*cpu_die)(unsigned int cpu);
        void (*play_dead)(void);
@@ -113,9 +115,9 @@ static inline void smp_cpus_done(unsigned int max_cpus)
        smp_ops.smp_cpus_done(max_cpus);
 }
-static inline int __cpu_up(unsigned int cpu)
+static inline int __cpu_up(unsigned int cpu, struct task_struct *tidle)
 {
-        return smp_ops.cpu_up(cpu);
+        return smp_ops.cpu_up(cpu, tidle);
 }
 static inline int __cpu_disable(void)
@@ -152,7 +154,7 @@ void cpu_disable_common(void);
 void native_smp_prepare_boot_cpu(void);
 void native_smp_prepare_cpus(unsigned int max_cpus);
 void native_smp_cpus_done(unsigned int max_cpus);
-int native_cpu_up(unsigned int cpunum);
+int native_cpu_up(unsigned int cpunum, struct task_struct *tidle);
 int native_cpu_disable(void);
 void native_cpu_die(unsigned int cpu);
 void native_play_dead(void);
@@ -162,6 +164,7 @@ int wbinvd_on_all_cpus(void);
 void native_send_call_func_ipi(const struct cpumask *mask);
 void native_send_call_func_single_ipi(int cpu);
+void x86_idle_thread_init(unsigned int cpu, struct task_struct *idle);
 void smp_store_cpu_info(int id);
 #define cpu_physical_id(cpu)    per_cpu(x86_cpu_to_apicid, cpu)
diff --git a/arch/x86/include/asm/thread_info.h b/arch/x86/include/asm/thread_info.h
index ad6df8ccd715..73cfe0d309c9 100644
--- a/arch/x86/include/asm/thread_info.h
+++ b/arch/x86/include/asm/thread_info.h
@@ -155,24 +155,6 @@ struct thread_info {
 #define PREEMPT_ACTIVE          0x10000000
-/* thread information allocation */
-#ifdef CONFIG_DEBUG_STACK_USAGE
-#define THREAD_FLAGS (GFP_KERNEL | __GFP_NOTRACK | __GFP_ZERO)
-#else
-#define THREAD_FLAGS (GFP_KERNEL | __GFP_NOTRACK)
-#endif
-#define __HAVE_ARCH_THREAD_INFO_ALLOCATOR
-#define alloc_thread_info_node(tsk, node)                               \
-({                                                                      \
-        struct page *page = alloc_pages_node(node, THREAD_FLAGS,        \
-                                             THREAD_ORDER);             \
-        struct thread_info *ret = page ? page_address(page) : NULL;     \
-                                                                        \
-        ret;                                                            \
-})
 #ifdef CONFIG_X86_32
 #define STACK_WARN      (THREAD_SIZE/8)
@@ -282,8 +264,7 @@ static inline bool is_ia32_task(void)
 #ifndef __ASSEMBLY__
 extern void arch_task_cache_init(void);
-extern void free_thread_info(struct thread_info *ti);
 extern int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src);
-#define arch_task_cache_init arch_task_cache_init
+extern void arch_release_task_struct(struct task_struct *tsk);
 #endif
 #endif /* _ASM_X86_THREAD_INFO_H */
diff --git a/arch/x86/kernel/Makefile b/arch/x86/kernel/Makefile
index 532d2e090e6f..56ebd1f98447 100644
--- a/arch/x86/kernel/Makefile
+++ b/arch/x86/kernel/Makefile
@@ -2,7 +2,7 @@
 # Makefile for the linux kernel.
 #
-extra-y                := head_$(BITS).o head$(BITS).o head.o init_task.o vmlinux.lds
+extra-y                := head_$(BITS).o head$(BITS).o head.o vmlinux.lds
 CPPFLAGS_vmlinux.lds += -U$(UTS_MACHINE)
diff --git a/arch/x86/kernel/apm_32.c b/arch/x86/kernel/apm_32.c
index 459e78cbf61e..07b0c0db466c 100644
--- a/arch/x86/kernel/apm_32.c
+++ b/arch/x86/kernel/apm_32.c
@@ -2401,7 +2401,7 @@ static void __exit apm_exit(void)
                 * (pm_idle), Wait for all processors to update cached/local
                 * copies of pm_idle before proceeding.
                 */
-                cpu_idle_wait();
+                kick_all_cpus_sync();
        }
        if (((apm_info.bios.flags & APM_BIOS_DISENGAGED) == 0)
            && (apm_info.connection_version > 0x0100)) {
diff --git a/arch/x86/kernel/init_task.c b/arch/x86/kernel/init_task.c
deleted file mode 100644
index 43e9ccf44947..000000000000
--- a/arch/x86/kernel/init_task.c
+++ /dev/null
@@ -1,42 +0,0 @@
-#include <linux/mm.h>
-#include <linux/module.h>
-#include <linux/sched.h>
-#include <linux/init.h>
-#include <linux/init_task.h>
-#include <linux/fs.h>
-#include <linux/mqueue.h>
-#include <asm/uaccess.h>
-#include <asm/pgtable.h>
-#include <asm/desc.h>
-static struct signal_struct init_signals = INIT_SIGNALS(init_signals);
-static struct sighand_struct init_sighand = INIT_SIGHAND(init_sighand);
-/*
- * Initial thread structure.
- *
- * We need to make sure that this is THREAD_SIZE aligned due to the
- * way process stacks are handled. This is done by having a special
- * "init_task" linker map entry..
- */
-union thread_union init_thread_union __init_task_data =
-        { INIT_THREAD_INFO(init_task) };
-/*
- * Initial task structure.
- *
- * All other task structs will be allocated on slabs in fork.c
- */
-struct task_struct init_task = INIT_TASK(init_task);
-EXPORT_SYMBOL(init_task);
-/*
- * per-CPU TSS segments. Threads are completely 'soft' on Linux,
- * no more per-task TSS's. The TSS size is kept cacheline-aligned
- * so they are allowed to end up in the .data..cacheline_aligned
- * section. Since TSS's are completely CPU-local, we want them
- * on exact cacheline boundaries, to eliminate cacheline ping-pong.
- */
-DEFINE_PER_CPU_SHARED_ALIGNED(struct tss_struct, init_tss) = INIT_TSS;
diff --git a/arch/x86/kernel/irq_32.c b/arch/x86/kernel/irq_32.c
index 58b7f27cb3e9..344faf8d0d62 100644
--- a/arch/x86/kernel/irq_32.c
+++ b/arch/x86/kernel/irq_32.c
@@ -127,8 +127,8 @@ void __cpuinit irq_ctx_init(int cpu)
                return;
        irqctx = page_address(alloc_pages_node(cpu_to_node(cpu),
-                                               THREAD_FLAGS,
+                                               THREADINFO_GFP,
-                                               THREAD_ORDER));
+                                               THREAD_SIZE_ORDER));
        memset(&irqctx->tinfo, 0, sizeof(struct thread_info));
        irqctx->tinfo.cpu               = cpu;
        irqctx->tinfo.preempt_count     = HARDIRQ_OFFSET;
@@ -137,8 +137,8 @@ void __cpuinit irq_ctx_init(int cpu)
        per_cpu(hardirq_ctx, cpu) = irqctx;
        irqctx = page_address(alloc_pages_node(cpu_to_node(cpu),
-                                               THREAD_FLAGS,
+                                               THREADINFO_GFP,
-                                               THREAD_ORDER));
+                                               THREAD_SIZE_ORDER));
        memset(&irqctx->tinfo, 0, sizeof(struct thread_info));
        irqctx->tinfo.cpu               = cpu;
        irqctx->tinfo.addr_limit        = MAKE_MM_SEG(0);
diff --git a/arch/x86/kernel/process.c b/arch/x86/kernel/process.c
index 1d92a5ab6e8b..e8173154800d 100644
--- a/arch/x86/kernel/process.c
+++ b/arch/x86/kernel/process.c
@@ -27,6 +27,15 @@
 #include <asm/debugreg.h>
 #include <asm/nmi.h>
+/*
+ * per-CPU TSS segments. Threads are completely 'soft' on Linux,
+ * no more per-task TSS's. The TSS size is kept cacheline-aligned
+ * so they are allowed to end up in the .data..cacheline_aligned
+ * section. Since TSS's are completely CPU-local, we want them
+ * on exact cacheline boundaries, to eliminate cacheline ping-pong.
+ */
+DEFINE_PER_CPU_SHARED_ALIGNED(struct tss_struct, init_tss) = INIT_TSS;
 #ifdef CONFIG_X86_64
 static DEFINE_PER_CPU(unsigned char, is_idle);
 static ATOMIC_NOTIFIER_HEAD(idle_notifier);
@@ -67,10 +76,9 @@ void free_thread_xstate(struct task_struct *tsk)
        fpu_free(&tsk->thread.fpu);
 }
-void free_thread_info(struct thread_info *ti)
+void arch_release_task_struct(struct task_struct *tsk)
 {
-        free_thread_xstate(ti->task);
+        free_thread_xstate(tsk);
-        free_pages((unsigned long)ti, THREAD_ORDER);
 }
 void arch_task_cache_init(void)
@@ -516,26 +524,6 @@ void stop_this_cpu(void *dummy)
        }
 }
-static void do_nothing(void *unused)
-{
-}
-/*
- * cpu_idle_wait - Used to ensure that all the CPUs discard old value of
- * pm_idle and update to new pm_idle value. Required while changing pm_idle
- * handler on SMP systems.
- *
- * Caller must have changed pm_idle to the new value before the call. Old
- * pm_idle value will not be used by any CPU after the return of this function.
- */
-void cpu_idle_wait(void)
-{
-        smp_mb();
-        /* kick all the CPUs so that they exit out of pm_idle */
-        smp_call_function(do_nothing, NULL, 1);
-}
-EXPORT_SYMBOL_GPL(cpu_idle_wait);
 /* Default MONITOR/MWAIT with no hints, used for default C1 state */
 static void mwait_idle(void)
 {
diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c
index 6e1e406038c2..3acaf51dfddb 100644
--- a/arch/x86/kernel/smpboot.c
+++ b/arch/x86/kernel/smpboot.c
@@ -76,20 +76,8 @@
 /* State of each CPU */
 DEFINE_PER_CPU(int, cpu_state) = { 0 };
-/* Store all idle threads, this can be reused instead of creating
-* a new thread. Also avoids complicated thread destroy functionality
-* for idle threads.
-*/
 #ifdef CONFIG_HOTPLUG_CPU
 /*
- * Needed only for CONFIG_HOTPLUG_CPU because __cpuinitdata is
- * removed after init for !CONFIG_HOTPLUG_CPU.
- */
-static DEFINE_PER_CPU(struct task_struct *, idle_thread_array);
-#define get_idle_for_cpu(x)      (per_cpu(idle_thread_array, x))
-#define set_idle_for_cpu(x, p)   (per_cpu(idle_thread_array, x) = (p))
-/*
 * We need this for trampoline_base protection from concurrent accesses when
 * off- and onlining cores wildly.
 */
@@ -97,20 +85,16 @@ static DEFINE_MUTEX(x86_cpu_hotplug_driver_mutex);
 void cpu_hotplug_driver_lock(void)
 {
-        mutex_lock(&x86_cpu_hotplug_driver_mutex);
+        mutex_lock(&x86_cpu_hotplug_driver_mutex);
 }
 void cpu_hotplug_driver_unlock(void)
 {
-        mutex_unlock(&x86_cpu_hotplug_driver_mutex);
+        mutex_unlock(&x86_cpu_hotplug_driver_mutex);
 }
 ssize_t arch_cpu_probe(const char *buf, size_t count) { return -1; }
 ssize_t arch_cpu_release(const char *buf, size_t count) { return -1; }
-#else
-static struct task_struct *idle_thread_array[NR_CPUS] __cpuinitdata ;
-#define get_idle_for_cpu(x)      (idle_thread_array[(x)])
-#define set_idle_for_cpu(x, p)   (idle_thread_array[(x)] = (p))
 #endif
 /* Number of siblings per CPU package */
@@ -618,22 +602,6 @@ wakeup_secondary_cpu_via_init(int phys_apicid, unsigned long start_eip)
        return (send_status | accept_status);
 }
-struct create_idle {
-        struct work_struct work;
-        struct task_struct *idle;
-        struct completion done;
-        int cpu;
-};
-static void __cpuinit do_fork_idle(struct work_struct *work)
-{
-        struct create_idle *c_idle =
-                container_of(work, struct create_idle, work);
-        c_idle->idle = fork_idle(c_idle->cpu);
-        complete(&c_idle->done);
-}
 /* reduce the number of lines printed when booting a large cpu count system */
 static void __cpuinit announce_cpu(int cpu, int apicid)
 {
@@ -660,58 +628,31 @@ static void __cpuinit announce_cpu(int cpu, int apicid)
 * Returns zero if CPU booted OK, else error code from
 * ->wakeup_secondary_cpu.
 */
-static int __cpuinit do_boot_cpu(int apicid, int cpu)
+static int __cpuinit do_boot_cpu(int apicid, int cpu, struct task_struct *idle)
 {
        unsigned long boot_error = 0;
        unsigned long start_ip;
        int timeout;
-        struct create_idle c_idle = {
-                .cpu    = cpu,
-                .done   = COMPLETION_INITIALIZER_ONSTACK(c_idle.done),
-        };
-        INIT_WORK_ONSTACK(&c_idle.work, do_fork_idle);
        alternatives_smp_switch(1);
-        c_idle.idle = get_idle_for_cpu(cpu);
+        idle->thread.sp = (unsigned long) (((struct pt_regs *)
+                          (THREAD_SIZE +  task_stack_page(idle))) - 1);
-        /*
+        per_cpu(current_task, cpu) = idle;
-         * We can't use kernel_thread since we must avoid to
-         * reschedule the child.
-         */
-        if (c_idle.idle) {
-                c_idle.idle->thread.sp = (unsigned long) (((struct pt_regs *)
-                        (THREAD_SIZE +  task_stack_page(c_idle.idle))) - 1);
-                init_idle(c_idle.idle, cpu);
-                goto do_rest;
-        }
-        schedule_work(&c_idle.work);
-        wait_for_completion(&c_idle.done);
-        if (IS_ERR(c_idle.idle)) {
-                printk("failed fork for CPU %d\n", cpu);
-                destroy_work_on_stack(&c_idle.work);
-                return PTR_ERR(c_idle.idle);
-        }
-        set_idle_for_cpu(cpu, c_idle.idle);
-do_rest:
-        per_cpu(current_task, cpu) = c_idle.idle;
 #ifdef CONFIG_X86_32
        /* Stack for startup_32 can be just as for start_secondary onwards */
        irq_ctx_init(cpu);
 #else
-        clear_tsk_thread_flag(c_idle.idle, TIF_FORK);
+        clear_tsk_thread_flag(idle, TIF_FORK);
        initial_gs = per_cpu_offset(cpu);
        per_cpu(kernel_stack, cpu) =
-                (unsigned long)task_stack_page(c_idle.idle) -
+                (unsigned long)task_stack_page(idle) -
                KERNEL_STACK_OFFSET + THREAD_SIZE;
 #endif
        early_gdt_descr.address = (unsigned long)get_cpu_gdt_table(cpu);
        initial_code = (unsigned long)start_secondary;
-        stack_start  = c_idle.idle->thread.sp;
+        stack_start  = idle->thread.sp;
        /* start_ip had better be page-aligned! */
        start_ip = trampoline_address();
@@ -813,12 +754,10 @@ do_rest:
                 */
                smpboot_restore_warm_reset_vector();
        }
-        destroy_work_on_stack(&c_idle.work);
        return boot_error;
 }
-int __cpuinit native_cpu_up(unsigned int cpu)
+int __cpuinit native_cpu_up(unsigned int cpu, struct task_struct *tidle)
 {
        int apicid = apic->cpu_present_to_apicid(cpu);
        unsigned long flags;
@@ -851,7 +790,7 @@ int __cpuinit native_cpu_up(unsigned int cpu)
        per_cpu(cpu_state, cpu) = CPU_UP_PREPARE;
-        err = do_boot_cpu(apicid, cpu);
+        err = do_boot_cpu(apicid, cpu, tidle);
        if (err) {
                pr_debug("do_boot_cpu failed %d\n", err);
                return -EIO;
diff --git a/arch/x86/xen/smp.c b/arch/x86/xen/smp.c
index 0503c0c493a9..3700945ed0d5 100644
--- a/arch/x86/xen/smp.c
+++ b/arch/x86/xen/smp.c
@@ -265,18 +265,8 @@ static void __init xen_smp_prepare_cpus(unsigned int max_cpus)
                set_cpu_possible(cpu, false);
        }
-        for_each_possible_cpu (cpu) {
+        for_each_possible_cpu(cpu)
-                struct task_struct *idle;
-                if (cpu == 0)
-                        continue;
-                idle = fork_idle(cpu);
-                if (IS_ERR(idle))
-                        panic("failed fork for CPU %d", cpu);
                set_cpu_present(cpu, true);
-        }
 }
 static int __cpuinit
@@ -346,9 +336,8 @@ cpu_initialize_context(unsigned int cpu, struct task_struct *idle)
        return 0;
 }
-static int __cpuinit xen_cpu_up(unsigned int cpu)
+static int __cpuinit xen_cpu_up(unsigned int cpu, struct task_struct *idle)
 {
-        struct task_struct *idle = idle_task(cpu);
        int rc;
        per_cpu(current_task, cpu) = idle;
@@ -562,10 +551,10 @@ static void __init xen_hvm_smp_prepare_cpus(unsigned int max_cpus)
        xen_init_lock_cpu(0);
 }
-static int __cpuinit xen_hvm_cpu_up(unsigned int cpu)
+static int __cpuinit xen_hvm_cpu_up(unsigned int cpu, struct task_struct *tidle)
 {
        int rc;
-        rc = native_cpu_up(cpu);
+        rc = native_cpu_up(cpu, tidle);
        WARN_ON (xen_smp_intr_init(cpu));
        return rc;
 }
diff --git a/arch/xtensa/kernel/Makefile b/arch/xtensa/kernel/Makefile
index 2d2728b3e862..59fc3fe15572 100644
--- a/arch/xtensa/kernel/Makefile
+++ b/arch/xtensa/kernel/Makefile
@@ -6,7 +6,7 @@ extra-y := head.o vmlinux.lds
 obj-y := align.o entry.o irq.o coprocessor.o process.o ptrace.o \
         setup.o signal.o syscall.o time.o traps.o vectors.o platform.o  \
-         pci-dma.o init_task.o io.o
+         pci-dma.o io.o
 obj-$(CONFIG_KGDB) += xtensa-stub.o
 obj-$(CONFIG_PCI) += pci.o
diff --git a/arch/xtensa/kernel/init_task.c b/arch/xtensa/kernel/init_task.c
deleted file mode 100644
index cd122fb7e48a..000000000000
--- a/arch/xtensa/kernel/init_task.c
+++ /dev/null
@@ -1,31 +0,0 @@
-/*
- * arch/xtensa/kernel/init_task.c
- *
- * Xtensa Processor version.
- *
- * This file is subject to the terms and conditions of the GNU General Public
- * License.  See the file "COPYING" in the main directory of this archive
- * for more details.
- *
- * Copyright (C) 2007 Tensilica Inc.
- *
- * Chris Zankel <chris@zankel.net>
- */
-#include <linux/mm.h>
-#include <linux/fs.h>
-#include <linux/init.h>
-#include <linux/init_task.h>
-#include <linux/module.h>
-#include <linux/mqueue.h>
-#include <asm/uaccess.h>
-static struct signal_struct init_signals = INIT_SIGNALS(init_signals);
-static struct sighand_struct init_sighand = INIT_SIGHAND(init_sighand);
-union thread_union init_thread_union __init_task_data =
-        { INIT_THREAD_INFO(init_task) };
-struct task_struct init_task = INIT_TASK(init_task);
-EXPORT_SYMBOL(init_task);
diff --git a/drivers/cpuidle/cpuidle.c b/drivers/cpuidle/cpuidle.c
index 2f0083a51a9a..d90519cec880 100644
--- a/drivers/cpuidle/cpuidle.c
+++ b/drivers/cpuidle/cpuidle.c
@@ -40,17 +40,6 @@ void disable_cpuidle(void)
        off = 1;
 }
-#if defined(CONFIG_ARCH_HAS_CPU_IDLE_WAIT)
-static void cpuidle_kick_cpus(void)
-{
-        cpu_idle_wait();
-}
-#elif defined(CONFIG_SMP)
-# error "Arch needs cpu_idle_wait() equivalent here"
-#else /* !CONFIG_ARCH_HAS_CPU_IDLE_WAIT && !CONFIG_SMP */
-static void cpuidle_kick_cpus(void) {}
-#endif
 static int __cpuidle_register_device(struct cpuidle_device *dev);
 static inline int cpuidle_enter(struct cpuidle_device *dev,
@@ -186,7 +175,7 @@ void cpuidle_uninstall_idle_handler(void)
 {
        if (enabled_devices) {
                initialized = 0;
-                cpuidle_kick_cpus();
+                kick_all_cpus_sync();
        }
 }
diff --git a/include/linux/smp.h b/include/linux/smp.h
index 10530d92c04b..717fb746c9a8 100644
--- a/include/linux/smp.h
+++ b/include/linux/smp.h
@@ -61,7 +61,7 @@ extern void smp_prepare_cpus(unsigned int max_cpus);
 /*
 * Bring a CPU up
 */
-extern int __cpu_up(unsigned int cpunum);
+extern int __cpu_up(unsigned int cpunum, struct task_struct *tidle);
 /*
 * Final polishing of CPUs
@@ -81,6 +81,8 @@ void __smp_call_function_single(int cpuid, struct call_single_data *data,
 int smp_call_function_any(const struct cpumask *mask,
                          smp_call_func_t func, void *info, int wait);
+void kick_all_cpus_sync(void);
 /*
 * Generic and arch helpers
 */
@@ -192,6 +194,8 @@ smp_call_function_any(const struct cpumask *mask, smp_call_func_t func,
        return smp_call_function_single(0, func, info, wait);
 }
+static inline void kick_all_cpus_sync(void) {  }
 #endif /* !SMP */
 /*
diff --git a/include/linux/thread_info.h b/include/linux/thread_info.h
index 8d03f079688c..db78775eff3b 100644
--- a/include/linux/thread_info.h
+++ b/include/linux/thread_info.h
@@ -54,6 +54,12 @@ extern long do_no_restart_syscall(struct restart_block *parm);
 #ifdef __KERNEL__
+#ifdef CONFIG_DEBUG_STACK_USAGE
+# define THREADINFO_GFP         (GFP_KERNEL | __GFP_NOTRACK | __GFP_ZERO)
+#else
+# define THREADINFO_GFP         (GFP_KERNEL | __GFP_NOTRACK)
+#endif
 /*
 * flag set/clear/test wrappers
 * - pass TIF_xxxx constants to these functions
diff --git a/init/Makefile b/init/Makefile
index 0bf677aa0872..7bc47ee31c36 100644
--- a/init/Makefile
+++ b/init/Makefile
@@ -10,6 +10,10 @@ obj-$(CONFIG_BLK_DEV_INITRD)   += initramfs.o
 endif
 obj-$(CONFIG_GENERIC_CALIBRATE_DELAY) += calibrate.o
+ifneq ($(CONFIG_ARCH_INIT_TASK),y)
+obj-y                          += init_task.o
+endif
 mounts-y                        := do_mounts.o
 mounts-$(CONFIG_BLK_DEV_RAM)    += do_mounts_rd.o
 mounts-$(CONFIG_BLK_DEV_INITRD) += do_mounts_initrd.o
diff --git a/arch/alpha/kernel/init_task.c b/init/init_task.c
index 6f80ca4f9766..8b2f3996b035 100644
--- a/arch/alpha/kernel/init_task.c
+++ b/init/init_task.c
@@ -1,17 +1,24 @@
-#include <linux/mm.h>
+#include <linux/init_task.h>
-#include <linux/module.h>
+#include <linux/export.h>
+#include <linux/mqueue.h>
 #include <linux/sched.h>
 #include <linux/init.h>
-#include <linux/init_task.h>
 #include <linux/fs.h>
-#include <linux/mqueue.h>
+#include <linux/mm.h>
-#include <asm/uaccess.h>
+#include <asm/pgtable.h>
+#include <asm/uaccess.h>
 static struct signal_struct init_signals = INIT_SIGNALS(init_signals);
 static struct sighand_struct init_sighand = INIT_SIGHAND(init_sighand);
+/* Initial task structure */
 struct task_struct init_task = INIT_TASK(init_task);
 EXPORT_SYMBOL(init_task);
+/*
+ * Initial thread structure. Alignment of this is handled by a special
+ * linker map entry.
+ */
 union thread_union init_thread_union __init_task_data =
        { INIT_THREAD_INFO(init_task) };
diff --git a/kernel/Makefile b/kernel/Makefile
index cb41b9547c9f..6c07f30fa9b7 100644
--- a/kernel/Makefile
+++ b/kernel/Makefile
@@ -43,6 +43,7 @@ obj-$(CONFIG_DEBUG_RT_MUTEXES) += rtmutex-debug.o
 obj-$(CONFIG_RT_MUTEX_TESTER) += rtmutex-tester.o
 obj-$(CONFIG_GENERIC_ISA_DMA) += dma.o
 obj-$(CONFIG_SMP) += smp.o
+obj-$(CONFIG_SMP) += smpboot.o
 ifneq ($(CONFIG_SMP),y)
 obj-y += up.o
 endif
diff --git a/kernel/cpu.c b/kernel/cpu.c
index 2060c6e57027..0e6353cf147a 100644
--- a/kernel/cpu.c
+++ b/kernel/cpu.c
@@ -17,6 +17,8 @@
 #include <linux/gfp.h>
 #include <linux/suspend.h>
+#include "smpboot.h"
 #ifdef CONFIG_SMP
 /* Serializes the updates to cpu_online_mask, cpu_present_mask */
 static DEFINE_MUTEX(cpu_add_remove_lock);
@@ -295,11 +297,19 @@ static int __cpuinit _cpu_up(unsigned int cpu, int tasks_frozen)
        int ret, nr_calls = 0;
        void *hcpu = (void *)(long)cpu;
        unsigned long mod = tasks_frozen ? CPU_TASKS_FROZEN : 0;
+        struct task_struct *idle;
        if (cpu_online(cpu) || !cpu_present(cpu))
                return -EINVAL;
        cpu_hotplug_begin();
+        idle = idle_thread_get(cpu);
+        if (IS_ERR(idle)) {
+                ret = PTR_ERR(idle);
+                goto out;
+        }
        ret = __cpu_notify(CPU_UP_PREPARE | mod, hcpu, -1, &nr_calls);
        if (ret) {
                nr_calls--;
@@ -309,7 +319,7 @@ static int __cpuinit _cpu_up(unsigned int cpu, int tasks_frozen)
        }
        /* Arch-specific enabling code. */
-        ret = __cpu_up(cpu);
+        ret = __cpu_up(cpu, idle);
        if (ret != 0)
                goto out_notify;
        BUG_ON(!cpu_online(cpu));
@@ -320,6 +330,7 @@ static int __cpuinit _cpu_up(unsigned int cpu, int tasks_frozen)
 out_notify:
        if (ret != 0)
                __cpu_notify(CPU_UP_CANCELED | mod, hcpu, nr_calls, NULL);
+out:
        cpu_hotplug_done();
        return ret;
diff --git a/kernel/fork.c b/kernel/fork.c
index 687a15d56243..9f9b296fa6df 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -112,32 +112,67 @@ int nr_processes(void)
        return total;
 }
-#ifndef __HAVE_ARCH_TASK_STRUCT_ALLOCATOR
+#ifndef CONFIG_ARCH_TASK_STRUCT_ALLOCATOR
-# define alloc_task_struct_node(node)           \
-                kmem_cache_alloc_node(task_struct_cachep, GFP_KERNEL, node)
-# define free_task_struct(tsk)                  \
-                kmem_cache_free(task_struct_cachep, (tsk))
 static struct kmem_cache *task_struct_cachep;
+static inline struct task_struct *alloc_task_struct_node(int node)
+{
+        return kmem_cache_alloc_node(task_struct_cachep, GFP_KERNEL, node);
+}
+void __weak arch_release_task_struct(struct task_struct *tsk) { }
+static inline void free_task_struct(struct task_struct *tsk)
+{
+        arch_release_task_struct(tsk);
+        kmem_cache_free(task_struct_cachep, tsk);
+}
 #endif
-#ifndef __HAVE_ARCH_THREAD_INFO_ALLOCATOR
+#ifndef CONFIG_ARCH_THREAD_INFO_ALLOCATOR
+void __weak arch_release_thread_info(struct thread_info *ti) { }
+/*
+ * Allocate pages if THREAD_SIZE is >= PAGE_SIZE, otherwise use a
+ * kmemcache based allocator.
+ */
+# if THREAD_SIZE >= PAGE_SIZE
 static struct thread_info *alloc_thread_info_node(struct task_struct *tsk,
                                                  int node)
 {
-#ifdef CONFIG_DEBUG_STACK_USAGE
+        struct page *page = alloc_pages_node(node, THREADINFO_GFP,
-        gfp_t mask = GFP_KERNEL | __GFP_ZERO;
+                                             THREAD_SIZE_ORDER);
-#else
-        gfp_t mask = GFP_KERNEL;
-#endif
-        struct page *page = alloc_pages_node(node, mask, THREAD_SIZE_ORDER);
        return page ? page_address(page) : NULL;
 }
 static inline void free_thread_info(struct thread_info *ti)
 {
+        arch_release_thread_info(ti);
        free_pages((unsigned long)ti, THREAD_SIZE_ORDER);
 }
+# else
+static struct kmem_cache *thread_info_cache;
+static struct thread_info *alloc_thread_info_node(struct task_struct *tsk,
+                                                  int node)
+{
+        return kmem_cache_alloc_node(thread_info_cache, THREADINFO_GFP, node);
+}
+static void free_thread_info(struct thread_info *ti)
+{
+        arch_release_thread_info(ti);
+        kmem_cache_free(thread_info_cache, ti);
+}
+void thread_info_cache_init(void)
+{
+        thread_info_cache = kmem_cache_create("thread_info", THREAD_SIZE,
+                                              THREAD_SIZE, 0, NULL);
+        BUG_ON(thread_info_cache == NULL);
+}
+# endif
 #endif
 /* SLAB cache for signal_struct structures (tsk->signal) */
@@ -204,17 +239,11 @@ void __put_task_struct(struct task_struct *tsk)
 }
 EXPORT_SYMBOL_GPL(__put_task_struct);
-/*
+void __init __weak arch_task_cache_init(void) { }
- * macro override instead of weak attribute alias, to workaround
- * gcc 4.1.0 and 4.1.1 bugs with weak attribute and empty functions.
- */
-#ifndef arch_task_cache_init
-#define arch_task_cache_init()
-#endif
 void __init fork_init(unsigned long mempages)
 {
-#ifndef __HAVE_ARCH_TASK_STRUCT_ALLOCATOR
+#ifndef CONFIG_ARCH_TASK_STRUCT_ALLOCATOR
 #ifndef ARCH_MIN_TASKALIGN
 #define ARCH_MIN_TASKALIGN      L1_CACHE_BYTES
 #endif
diff --git a/kernel/sched/Makefile b/kernel/sched/Makefile
index 9a7dd35102a3..173ea52f3af0 100644
--- a/kernel/sched/Makefile
+++ b/kernel/sched/Makefile
@@ -16,5 +16,3 @@ obj-$(CONFIG_SMP) += cpupri.o
 obj-$(CONFIG_SCHED_AUTOGROUP) += auto_group.o
 obj-$(CONFIG_SCHEDSTATS) += stats.o
 obj-$(CONFIG_SCHED_DEBUG) += debug.o
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index eb4131b8ad60..ea8a4769fea5 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -83,6 +83,7 @@
 #include "sched.h"
 #include "../workqueue_sched.h"
+#include "../smpboot.h"
 #define CREATE_TRACE_POINTS
 #include <trace/events/sched.h>
@@ -7062,6 +7063,7 @@ void __init sched_init(void)
        /* May be allocated at isolcpus cmdline parse time */
        if (cpu_isolated_map == NULL)
                zalloc_cpumask_var(&cpu_isolated_map, GFP_NOWAIT);
+        idle_thread_set_boot_cpu();
 #endif
        init_sched_fair_class();
diff --git a/kernel/smp.c b/kernel/smp.c
index 2f8b10ecf759..d0ae5b24875e 100644
--- a/kernel/smp.c
+++ b/kernel/smp.c
@@ -13,6 +13,8 @@
 #include <linux/smp.h>
 #include <linux/cpu.h>
+#include "smpboot.h"
 #ifdef CONFIG_USE_GENERIC_SMP_HELPERS
 static struct {
        struct list_head        queue;
@@ -669,6 +671,8 @@ void __init smp_init(void)
 {
        unsigned int cpu;
+        idle_threads_init();
        /* FIXME: This should be done in userspace --RR */
        for_each_present_cpu(cpu) {
                if (num_online_cpus() >= setup_max_cpus)
@@ -791,3 +795,26 @@ void on_each_cpu_cond(bool (*cond_func)(int cpu, void *info),
        }
 }
 EXPORT_SYMBOL(on_each_cpu_cond);
+static void do_nothing(void *unused)
+{
+}
+/**
+ * kick_all_cpus_sync - Force all cpus out of idle
+ *
+ * Used to synchronize the update of pm_idle function pointer. It's
+ * called after the pointer is updated and returns after the dummy
+ * callback function has been executed on all cpus. The execution of
+ * the function can only happen on the remote cpus after they have
+ * left the idle function which had been called via pm_idle function
+ * pointer. So it's guaranteed that nothing uses the previous pointer
+ * anymore.
+ */
+void kick_all_cpus_sync(void)
+{
+        /* Make sure the change is visible before we kick the cpus */
+        smp_mb();
+        smp_call_function(do_nothing, NULL, 1);
+}
+EXPORT_SYMBOL_GPL(kick_all_cpus_sync);
diff --git a/kernel/smpboot.c b/kernel/smpboot.c
new file mode 100644
index 000000000000..e1a797e028a3
--- /dev/null
+++ b/kernel/smpboot.c
@@ -0,0 +1,62 @@
+/*
+ * Common SMP CPU bringup/teardown functions
+ */
+#include <linux/err.h>
+#include <linux/smp.h>
+#include <linux/init.h>
+#include <linux/sched.h>
+#include <linux/percpu.h>
+#include "smpboot.h"
+#ifdef CONFIG_GENERIC_SMP_IDLE_THREAD
+/*
+ * For the hotplug case we keep the task structs around and reuse
+ * them.
+ */
+static DEFINE_PER_CPU(struct task_struct *, idle_threads);
+struct task_struct * __cpuinit idle_thread_get(unsigned int cpu)
+{
+        struct task_struct *tsk = per_cpu(idle_threads, cpu);
+        if (!tsk)
+                return ERR_PTR(-ENOMEM);
+        init_idle(tsk, cpu);
+        return tsk;
+}
+void __init idle_thread_set_boot_cpu(void)
+{
+        per_cpu(idle_threads, smp_processor_id()) = current;
+}
+static inline void idle_init(unsigned int cpu)
+{
+        struct task_struct *tsk = per_cpu(idle_threads, cpu);
+        if (!tsk) {
+                tsk = fork_idle(cpu);
+                if (IS_ERR(tsk))
+                        pr_err("SMP: fork_idle() failed for CPU %u\n", cpu);
+                else
+                        per_cpu(idle_threads, cpu) = tsk;
+        }
+}
+/**
+ * idle_thread_init - Initialize the idle thread for a cpu
+ * @cpu:        The cpu for which the idle thread should be initialized
+ *
+ * Creates the thread if it does not exist.
+ */
+void __init idle_threads_init(void)
+{
+        unsigned int cpu;
+        for_each_possible_cpu(cpu) {
+                if (cpu != smp_processor_id())
+                        idle_init(cpu);
+        }
+}
+#endif
diff --git a/kernel/smpboot.h b/kernel/smpboot.h
new file mode 100644
index 000000000000..80c0acfb8472
--- /dev/null
+++ b/kernel/smpboot.h
@@ -0,0 +1,18 @@
+#ifndef SMPBOOT_H
+#define SMPBOOT_H
+struct task_struct;
+int smpboot_prepare(unsigned int cpu);
+#ifdef CONFIG_GENERIC_SMP_IDLE_THREAD
+struct task_struct *idle_thread_get(unsigned int cpu);
+void idle_thread_set_boot_cpu(void);
+void idle_threads_init(void);
+#else
+static inline struct task_struct *idle_thread_get(unsigned int cpu) { return NULL; }
+static inline void idle_thread_set_boot_cpu(void) { }
+static inline void idle_threads_init(void) { }
+#endif
+#endif
author	Linus Torvalds <torvalds@linux-foundation.org>	2012-05-21 22:43:57 -0400
committer	Linus Torvalds <torvalds@linux-foundation.org>	2012-05-21 22:43:57 -0400
commit	bf67f3a5c456a18f2e8d062f7e88506ef2cd9837 (patch)
tree	2a2324b2572162059307db82f9238eeb25673a77
parent	226da0dbc84ed97f448523e2a4cb91c27fa68ed9 (diff)
parent	203dacbdca977bedaba61ad2fca75d934060a5d5 (diff)