9 files changed, 15 insertions, 36 deletions

diff --git a/arch/x86/include/asm/current.h b/arch/x86/include/asm/current.h
index 0728480f5c56..c68c361697e1 100644
--- a/arch/x86/include/asm/current.h
+++ b/arch/x86/include/asm/current.h
@@ -1,39 +1,21 @@
 #ifndef _ASM_X86_CURRENT_H
 #define _ASM_X86_CURRENT_H
 
-#ifdef CONFIG_X86_32
 #include <linux/compiler.h>
 #include <asm/percpu.h>
 
+#ifndef __ASSEMBLY__
 struct task_struct;
 
 DECLARE_PER_CPU(struct task_struct *, current_task);
-static __always_inline struct task_struct *get_current(void)
-{
-        return percpu_read(current_task);
-}
-
-#else /* X86_32 */
-
-#ifndef __ASSEMBLY__
-#include <asm/pda.h>
-
-struct task_struct;
 
 static __always_inline struct task_struct *get_current(void)
 {
-        return read_pda(pcurrent);
+        return percpu_read(current_task);
 }
 
-#else /* __ASSEMBLY__ */
-
-#include <asm/asm-offsets.h>
-#define GET_CURRENT(reg) movq %gs:(pda_pcurrent),reg
+#define current get_current()
 
 #endif /* __ASSEMBLY__ */
 
-#endif /* X86_32 */
-
-#define current get_current()
-
 #endif /* _ASM_X86_CURRENT_H */
diff --git a/arch/x86/include/asm/pda.h b/arch/x86/include/asm/pda.h
index 668d5a5b6f70..7209302d9227 100644
--- a/arch/x86/include/asm/pda.h
+++ b/arch/x86/include/asm/pda.h
@@ -11,8 +11,8 @@
 
 /* Per processor datastructure. %gs points to it while the kernel runs */
 struct x8664_pda {
-        struct task_struct *pcurrent;   /* 0  Current process */
-        unsigned long dummy;
+        unsigned long unused1;
+        unsigned long unused2;
         unsigned long kernelstack;      /* 16 top of kernel stack for current */
         unsigned long oldrsp;           /* 24 user rsp for system call */
         int irqcount;                   /* 32 Irq nesting counter. Starts -1 */
diff --git a/arch/x86/include/asm/system.h b/arch/x86/include/asm/system.h
index 8e626ea33a1a..4399aac680e9 100644
--- a/arch/x86/include/asm/system.h
+++ b/arch/x86/include/asm/system.h
@@ -94,7 +94,7 @@ do {									\
              "call __switch_to\n\t"                                       \
              ".globl thread_return\n"                                     \
              "thread_return:\n\t"                                         \
-             "movq %%gs:%P[pda_pcurrent],%%rsi\n\t"                       \
+             "movq "__percpu_seg_str"%P[current_task],%%rsi\n\t"          \
              "movq %P[thread_info](%%rsi),%%r8\n\t"                       \
              LOCK_PREFIX "btr  %[tif_fork],%P[ti_flags](%%r8)\n\t"        \
              "movq %%rax,%%rdi\n\t"                                       \
@@ -106,7 +106,7 @@ do {									\
                [ti_flags] "i" (offsetof(struct thread_info, flags)),      \
                [tif_fork] "i" (TIF_FORK),                                 \
                [thread_info] "i" (offsetof(struct task_struct, stack)),   \
-               [pda_pcurrent] "i" (offsetof(struct x8664_pda, pcurrent))  \
+               [current_task] "m" (per_cpu_var(current_task))             \
              : "memory", "cc" __EXTRA_CLOBBER)
 #endif
 
diff --git a/arch/x86/kernel/asm-offsets_64.c b/arch/x86/kernel/asm-offsets_64.c
index cae6697c0991..4f7a210e1e58 100644
--- a/arch/x86/kernel/asm-offsets_64.c
+++ b/arch/x86/kernel/asm-offsets_64.c
@@ -51,7 +51,6 @@ int main(void)
 #define ENTRY(entry) DEFINE(pda_ ## entry, offsetof(struct x8664_pda, entry))
         ENTRY(kernelstack); 
         ENTRY(oldrsp); 
-        ENTRY(pcurrent); 
         ENTRY(irqcount);
         DEFINE(pda_size, sizeof(struct x8664_pda));
         BLANK();
diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c
index 4221e920886d..b50e38d16888 100644
--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c
@@ -903,10 +903,7 @@ void __cpuinit pda_init(int cpu)
         pda->kernelstack = (unsigned long)stack_thread_info() -
                                  PDA_STACKOFFSET + THREAD_SIZE;
 
-        if (cpu == 0) {
-                /* others are initialized in smpboot.c */
-                pda->pcurrent = &init_task;
-        } else {
+        if (cpu != 0) {
                 if (pda->nodenumber == 0 && cpu_to_node(cpu) != NUMA_NO_NODE)
                         pda->nodenumber = cpu_to_node(cpu);
         }
diff --git a/arch/x86/kernel/dumpstack_64.c b/arch/x86/kernel/dumpstack_64.c
index 28e26a4315df..d35db5993fd6 100644
--- a/arch/x86/kernel/dumpstack_64.c
+++ b/arch/x86/kernel/dumpstack_64.c
@@ -242,7 +242,7 @@ void show_registers(struct pt_regs *regs)
         int i;
         unsigned long sp;
         const int cpu = smp_processor_id();
-        struct task_struct *cur = cpu_pda(cpu)->pcurrent;
+        struct task_struct *cur = current;
 
         sp = regs->sp;
         printk("CPU %d ", cpu);
diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c
index 416fb9282f4f..e00c31a4b3c0 100644
--- a/arch/x86/kernel/process_64.c
+++ b/arch/x86/kernel/process_64.c
@@ -57,6 +57,9 @@
 
 asmlinkage extern void ret_from_fork(void);
 
+DEFINE_PER_CPU(struct task_struct *, current_task) = &init_task;
+EXPORT_PER_CPU_SYMBOL(current_task);
+
 unsigned long kernel_thread_flags = CLONE_VM | CLONE_UNTRACED;
 
 static ATOMIC_NOTIFIER_HEAD(idle_notifier);
@@ -615,7 +618,7 @@ __switch_to(struct task_struct *prev_p, struct task_struct *next_p)
          */
         prev->usersp = read_pda(oldrsp);
         write_pda(oldrsp, next->usersp);
-        write_pda(pcurrent, next_p);
+        percpu_write(current_task, next_p);
 
         write_pda(kernelstack,
                   (unsigned long)task_stack_page(next_p) +
diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c
index 2f0e0f1090f6..5854be0fb804 100644
--- a/arch/x86/kernel/smpboot.c
+++ b/arch/x86/kernel/smpboot.c
@@ -790,13 +790,12 @@ static int __cpuinit do_boot_cpu(int apicid, int cpu)
 
         set_idle_for_cpu(cpu, c_idle.idle);
 do_rest:
-#ifdef CONFIG_X86_32
         per_cpu(current_task, cpu) = c_idle.idle;
+#ifdef CONFIG_X86_32
         init_gdt(cpu);
         /* Stack for startup_32 can be just as for start_secondary onwards */
         irq_ctx_init(cpu);
 #else
-        cpu_pda(cpu)->pcurrent = c_idle.idle;
         clear_tsk_thread_flag(c_idle.idle, TIF_FORK);
         initial_gs = per_cpu_offset(cpu);
 #endif
diff --git a/arch/x86/xen/smp.c b/arch/x86/xen/smp.c
index 9ff3b0999cfb..72c2eb9b64cd 100644
--- a/arch/x86/xen/smp.c
+++ b/arch/x86/xen/smp.c
@@ -279,12 +279,11 @@ static int __cpuinit xen_cpu_up(unsigned int cpu)
         struct task_struct *idle = idle_task(cpu);
         int rc;
 
+        per_cpu(current_task, cpu) = idle;
 #ifdef CONFIG_X86_32
         init_gdt(cpu);
-        per_cpu(current_task, cpu) = idle;
         irq_ctx_init(cpu);
 #else
-        cpu_pda(cpu)->pcurrent = idle;
         clear_tsk_thread_flag(idle, TIF_FORK);
 #endif
         xen_setup_timer(cpu);