avr32: switch to generic kernel_thread()/kernel_execve()

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

6 files changed, 28 insertions, 84 deletions

diff --git a/arch/avr32/Kconfig b/arch/avr32/Kconfig
index 06e73bf665e9..649aeb9acecb 100644
--- a/arch/avr32/Kconfig
+++ b/arch/avr32/Kconfig
@@ -17,6 +17,8 @@ config AVR32
         select GENERIC_CLOCKEVENTS
         select HAVE_MOD_ARCH_SPECIFIC
         select MODULES_USE_ELF_RELA
+        select GENERIC_KERNEL_THREAD
+        select GENERIC_KERNEL_EXECVE
         help
           AVR32 is a high-performance 32-bit RISC microprocessor core,
           designed for cost-sensitive embedded applications, with particular
diff --git a/arch/avr32/include/asm/processor.h b/arch/avr32/include/asm/processor.h
index 87d8baccc60e..48d71c5c898a 100644
--- a/arch/avr32/include/asm/processor.h
+++ b/arch/avr32/include/asm/processor.h
@@ -142,9 +142,6 @@ struct task_struct;
 /* Free all resources held by a thread */
 extern void release_thread(struct task_struct *);
 
-/* Create a kernel thread without removing it from tasklists */
-extern int kernel_thread(int (*fn)(void *), void *arg, unsigned long flags);
-
 /* Return saved PC of a blocked thread */
 #define thread_saved_pc(tsk)    ((tsk)->thread.cpu_context.pc)
 
diff --git a/arch/avr32/kernel/Makefile b/arch/avr32/kernel/Makefile
index 9e2c465ef3a6..119a2e41defe 100644
--- a/arch/avr32/kernel/Makefile
+++ b/arch/avr32/kernel/Makefile
@@ -7,7 +7,7 @@ extra-y				:= head.o vmlinux.lds
 obj-$(CONFIG_SUBARCH_AVR32B)    += entry-avr32b.o
 obj-y                           += syscall_table.o syscall-stubs.o irq.o
 obj-y                           += setup.o traps.o ocd.o ptrace.o
-obj-y                           += signal.o sys_avr32.o process.o time.o
+obj-y                           += signal.o process.o time.o
 obj-y                           += switch_to.o cpu.o
 obj-$(CONFIG_MODULES)           += module.o avr32_ksyms.o
 obj-$(CONFIG_KPROBES)           += kprobes.o
diff --git a/arch/avr32/kernel/entry-avr32b.S b/arch/avr32/kernel/entry-avr32b.S
index df2884181313..9899d3cc6f03 100644
--- a/arch/avr32/kernel/entry-avr32b.S
+++ b/arch/avr32/kernel/entry-avr32b.S
@@ -251,13 +251,15 @@ syscall_badsys:
         .global ret_from_fork
 ret_from_fork:
         call   schedule_tail
+        mov     r12, 0
+        rjmp    syscall_return
 
-        /* check for syscall tracing */
-        get_thread_info r0
-        ld.w    r1, r0[TI_flags]
-        andl    r1, _TIF_ALLWORK_MASK, COH
-        brne    syscall_exit_work
-        rjmp    syscall_exit_cont
+        .global ret_from_kernel_thread
+ret_from_kernel_thread:
+        call   schedule_tail
+        mov     r12, r0
+        mov     lr, r2  /* syscall_return */
+        mov     pc, r1
 
 syscall_trace_enter:
         pushm   r8-r12
diff --git a/arch/avr32/kernel/process.c b/arch/avr32/kernel/process.c
index 1bb0a8abd79b..07380c3a4f78 100644
--- a/arch/avr32/kernel/process.c
+++ b/arch/avr32/kernel/process.c
@@ -69,44 +69,6 @@ void machine_restart(char *cmd)
 }
 
 /*
- * PC is actually discarded when returning from a system call -- the
- * return address must be stored in LR. This function will make sure
- * LR points to do_exit before starting the thread.
- *
- * Also, when returning from fork(), r12 is 0, so we must copy the
- * argument as well.
- *
- *  r0 : The argument to the main thread function
- *  r1 : The address of do_exit
- *  r2 : The address of the main thread function
- */
-asmlinkage extern void kernel_thread_helper(void);
-__asm__("       .type   kernel_thread_helper, @function\n"
-        "kernel_thread_helper:\n"
-        "       mov     r12, r0\n"
-        "       mov     lr, r2\n"
-        "       mov     pc, r1\n"
-        "       .size   kernel_thread_helper, . - kernel_thread_helper");
-
-int kernel_thread(int (*fn)(void *), void *arg, unsigned long flags)
-{
-        struct pt_regs regs;
-
-        memset(&regs, 0, sizeof(regs));
-
-        regs.r0 = (unsigned long)arg;
-        regs.r1 = (unsigned long)fn;
-        regs.r2 = (unsigned long)do_exit;
-        regs.lr = (unsigned long)kernel_thread_helper;
-        regs.pc = (unsigned long)kernel_thread_helper;
-        regs.sr = MODE_SUPERVISOR;
-
-        return do_fork(flags | CLONE_VM | CLONE_UNTRACED,
-                       0, &regs, 0, NULL, NULL);
-}
-EXPORT_SYMBOL(kernel_thread);
-
-/*
  * Free current thread data structures etc
  */
 void exit_thread(void)
@@ -332,26 +294,31 @@ int dump_fpu(struct pt_regs *regs, elf_fpregset_t *fpu)
 }
 
 asmlinkage void ret_from_fork(void);
+asmlinkage void ret_from_kernel_thread(void);
+asmlinkage void syscall_return(void);
 
 int copy_thread(unsigned long clone_flags, unsigned long usp,
-                unsigned long unused,
+                unsigned long arg,
                 struct task_struct *p, struct pt_regs *regs)
 {
-        struct pt_regs *childregs;
-
-        childregs = ((struct pt_regs *)(THREAD_SIZE + (unsigned long)task_stack_page(p))) - 1;
-        *childregs = *regs;
-
-        if (user_mode(regs))
+        struct pt_regs *childregs = task_pt_regs(p);
+
+        if (unlikely(!regs)) {
+                memset(childregs, 0, sizeof(struct pt_regs));
+                p->thread.cpu_context.r0 = arg;
+                p->thread.cpu_context.r1 = usp; /* fn */
+                p->thread.cpu_context.r2 = syscall_return;
+                p->thread.cpu_context.pc = (unsigned long)ret_from_kernel_thread;
+                childregs->sr = MODE_SUPERVISOR;
+        } else {
+                *childregs = *regs;
                 childregs->sp = usp;
-        else
-                childregs->sp = (unsigned long)task_stack_page(p) + THREAD_SIZE;
-
-        childregs->r12 = 0; /* Set return value for child */
+                childregs->r12 = 0; /* Set return value for child */
+                p->thread.cpu_context.pc = (unsigned long)ret_from_fork;
+        }
 
         p->thread.cpu_context.sr = MODE_SUPERVISOR | SR_GM;
         p->thread.cpu_context.ksp = (unsigned long)childregs;
-        p->thread.cpu_context.pc = (unsigned long)ret_from_fork;
 
         clear_tsk_thread_flag(p, TIF_DEBUG);
         if ((clone_flags & CLONE_PTRACE) && test_thread_flag(TIF_DEBUG))
diff --git a/arch/avr32/kernel/sys_avr32.c b/arch/avr32/kernel/sys_avr32.c
deleted file mode 100644
index 62635a09ae3e..000000000000
--- a/arch/avr32/kernel/sys_avr32.c
+++ /dev/null
@@ -1,24 +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/unistd.h>
-
-int kernel_execve(const char *file,
-                  const char *const *argv,
-                  const char *const *envp)
-{
-        register long scno asm("r8") = __NR_execve;
-        register long sc1 asm("r12") = (long)file;
-        register long sc2 asm("r11") = (long)argv;
-        register long sc3 asm("r10") = (long)envp;
-
-        asm volatile("scall"
-                     : "=r"(sc1)
-                     : "r"(scno), "0"(sc1), "r"(sc2), "r"(sc3)
-                     : "cc", "memory");
-        return sc1;
-}