1 files changed, 16 insertions, 44 deletions

diff --git a/arch/sh/kernel/process_64.c b/arch/sh/kernel/process_64.c
index 98a709f0c3c4..fd338b030fd9 100644
--- a/arch/sh/kernel/process_64.c
+++ b/arch/sh/kernel/process_64.c
@@ -285,39 +285,6 @@ void show_regs(struct pt_regs *regs)
 }
 
 /*
- * Create a kernel thread
- */
-__noreturn void kernel_thread_helper(void *arg, int (*fn)(void *))
-{
-        do_exit(fn(arg));
-}
-
-/*
- * This is the mechanism for creating a new kernel thread.
- *
- * NOTE! Only a kernel-only process(ie the swapper or direct descendants
- * who haven't done an "execve()") should use this: it will work within
- * a system call from a "real" process, but the process memory space will
- * not be freed until both the parent and the child have exited.
- */
-int kernel_thread(int (*fn)(void *), void * arg, unsigned long flags)
-{
-        struct pt_regs regs;
-
-        memset(&regs, 0, sizeof(regs));
-        regs.regs[2] = (unsigned long)arg;
-        regs.regs[3] = (unsigned long)fn;
-
-        regs.pc = (unsigned long)kernel_thread_helper;
-        regs.sr = (1 << 30);
-
-        /* Ok, create the new process.. */
-        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)
@@ -401,15 +368,17 @@ int dump_fpu(struct pt_regs *regs, elf_fpregset_t *fpu)
 EXPORT_SYMBOL(dump_fpu);
 
 asmlinkage void ret_from_fork(void);
+asmlinkage void ret_from_kernel_thread(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;
 
 #ifdef CONFIG_SH_FPU
-        if(last_task_used_math == current) {
+        /* can't happen for a kernel thread */
+        if (last_task_used_math == current) {
                 enable_fpu();
                 save_fpu(current);
                 disable_fpu();
@@ -419,7 +388,17 @@ int copy_thread(unsigned long clone_flags, unsigned long usp,
 #endif
         /* Copy from sh version */
         childregs = (struct pt_regs *)(THREAD_SIZE + task_stack_page(p)) - 1;
+        p->thread.sp = (unsigned long) childregs;
 
+        if (unlikely(p->flags & PF_KTHREAD)) {
+                memset(childregs, 0, sizeof(struct pt_regs));
+                childregs->regs[2] = (unsigned long)arg;
+                childregs->regs[3] = (unsigned long)fn;
+                childregs->sr = (1 << 30); /* not user_mode */
+                childregs->sr |= SR_FD; /* Invalidate FPU flag */
+                p->thread.pc = (unsigned long) ret_from_kernel_thread;
+                return 0;
+        }
         *childregs = *regs;
 
         /*
@@ -428,19 +407,12 @@ int copy_thread(unsigned long clone_flags, unsigned long usp,
          * 32-bit wide and context switch must take care
          * of NEFF sign extension.
          */
-        if (user_mode(regs)) {
-                childregs->regs[15] = neff_sign_extend(usp);
-                p->thread.uregs = childregs;
-        } else {
-                childregs->regs[15] =
-                        neff_sign_extend((unsigned long)task_stack_page(p) +
-                                         THREAD_SIZE);
-        }
+        childregs->regs[15] = neff_sign_extend(usp);
+        p->thread.uregs = childregs;
 
         childregs->regs[9] = 0; /* Set return value for child */
         childregs->sr |= SR_FD; /* Invalidate FPU flag */
 
-        p->thread.sp = (unsigned long) childregs;
         p->thread.pc = (unsigned long) ret_from_fork;
 
         return 0;