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Diffstat (limited to 'arch/arm/kernel/process.c')
-rw-r--r--arch/arm/kernel/process.c75
1 files changed, 13 insertions, 62 deletions
diff --git a/arch/arm/kernel/process.c b/arch/arm/kernel/process.c
index 04eea22d7958..f98c17ff1957 100644
--- a/arch/arm/kernel/process.c
+++ b/arch/arm/kernel/process.c
@@ -373,6 +373,7 @@ void release_thread(struct task_struct *dead_task)
}
asmlinkage void ret_from_fork(void) __asm__("ret_from_fork");
+asmlinkage void ret_from_kernel_thread(void) __asm__("ret_from_kernel_thread");
int
copy_thread(unsigned long clone_flags, unsigned long stack_start,
@@ -381,13 +382,20 @@ copy_thread(unsigned long clone_flags, unsigned long stack_start,
struct thread_info *thread = task_thread_info(p);
struct pt_regs *childregs = task_pt_regs(p);
- *childregs = *regs;
- childregs->ARM_r0 = 0;
- childregs->ARM_sp = stack_start;
-
memset(&thread->cpu_context, 0, sizeof(struct cpu_context_save));
+
+ if (likely(regs)) {
+ *childregs = *regs;
+ childregs->ARM_r0 = 0;
+ childregs->ARM_sp = stack_start;
+ thread->cpu_context.pc = (unsigned long)ret_from_fork;
+ } else {
+ thread->cpu_context.r4 = stk_sz;
+ thread->cpu_context.r5 = stack_start;
+ thread->cpu_context.pc = (unsigned long)ret_from_kernel_thread;
+ childregs->ARM_cpsr = SVC_MODE;
+ }
thread->cpu_context.sp = (unsigned long)childregs;
- thread->cpu_context.pc = (unsigned long)ret_from_fork;
clear_ptrace_hw_breakpoint(p);
@@ -423,63 +431,6 @@ int dump_fpu (struct pt_regs *regs, struct user_fp *fp)
}
EXPORT_SYMBOL(dump_fpu);
-/*
- * Shuffle the argument into the correct register before calling the
- * thread function. r4 is the thread argument, r5 is the pointer to
- * the thread function, and r6 points to the exit function.
- */
-extern void kernel_thread_helper(void);
-asm( ".pushsection .text\n"
-" .align\n"
-" .type kernel_thread_helper, #function\n"
-"kernel_thread_helper:\n"
-#ifdef CONFIG_TRACE_IRQFLAGS
-" bl trace_hardirqs_on\n"
-#endif
-" msr cpsr_c, r7\n"
-" mov r0, r4\n"
-" mov lr, r6\n"
-" mov pc, r5\n"
-" .size kernel_thread_helper, . - kernel_thread_helper\n"
-" .popsection");
-
-#ifdef CONFIG_ARM_UNWIND
-extern void kernel_thread_exit(long code);
-asm( ".pushsection .text\n"
-" .align\n"
-" .type kernel_thread_exit, #function\n"
-"kernel_thread_exit:\n"
-" .fnstart\n"
-" .cantunwind\n"
-" bl do_exit\n"
-" nop\n"
-" .fnend\n"
-" .size kernel_thread_exit, . - kernel_thread_exit\n"
-" .popsection");
-#else
-#define kernel_thread_exit do_exit
-#endif
-
-/*
- * Create a kernel thread.
- */
-pid_t kernel_thread(int (*fn)(void *), void *arg, unsigned long flags)
-{
- struct pt_regs regs;
-
- memset(&regs, 0, sizeof(regs));
-
- regs.ARM_r4 = (unsigned long)arg;
- regs.ARM_r5 = (unsigned long)fn;
- regs.ARM_r6 = (unsigned long)kernel_thread_exit;
- regs.ARM_r7 = SVC_MODE | PSR_ENDSTATE | PSR_ISETSTATE;
- regs.ARM_pc = (unsigned long)kernel_thread_helper;
- regs.ARM_cpsr = regs.ARM_r7 | PSR_I_BIT;
-
- return do_fork(flags|CLONE_VM|CLONE_UNTRACED, 0, &regs, 0, NULL, NULL);
-}
-EXPORT_SYMBOL(kernel_thread);
-
unsigned long get_wchan(struct task_struct *p)
{
struct stackframe frame;