commit 7147e215480323bb2617fcebf585c447188ff760
author Al Viro <viro@zeniv.linux.org.uk> Sun Oct 14 01:41:42 2012 -0400
committer Al Viro <viro@zeniv.linux.org.uk> Mon Oct 22 22:31:01 2012 -0400
tree fb5d92e4f9e2f4d5d5c8e4449c4ef43e05275826
parent ddffeb8c4d0331609ef2581d84de4d763607bd37

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

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

arch/sh/kernel/process_32.c

diff --git a/arch/sh/kernel/process_32.c b/arch/sh/kernel/process_32.c
index ba7345f..b55070b 100644
--- a/arch/sh/kernel/process_32.c
+++ b/arch/sh/kernel/process_32.c
@@ -68,38 +68,6 @@
 	show_code(regs);
 }
 
-/*
- * Create a kernel thread
- */
-__noreturn void kernel_thread_helper(void *arg, int (*fn)(void *))
-{
-	do_exit(fn(arg));
-}
-
-/* Don't use this in BL=1(cli).  Or else, CPU resets! */
-int kernel_thread(int (*fn)(void *), void * arg, unsigned long flags)
-{
-	struct pt_regs regs;
-	int pid;
-
-	memset(&regs, 0, sizeof(regs));
-	regs.regs[4] = (unsigned long)arg;
-	regs.regs[5] = (unsigned long)fn;
-
-	regs.pc = (unsigned long)kernel_thread_helper;
-	regs.sr = SR_MD;
-#if defined(CONFIG_SH_FPU)
-	regs.sr |= SR_FD;
-#endif
-
-	/* Ok, create the new process.. */
-	pid = do_fork(flags | CLONE_VM | CLONE_UNTRACED, 0,
-		      &regs, 0, NULL, NULL);
-
-	return pid;
-}
-EXPORT_SYMBOL(kernel_thread);
-
 void start_thread(struct pt_regs *regs, unsigned long new_pc,
 		  unsigned long new_sp)
 {
@@ -157,9 +125,10 @@
 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 thread_info *ti = task_thread_info(p);
@@ -177,29 +146,34 @@
 	}
 #endif
 
-	childregs = task_pt_regs(p);
-	*childregs = *regs;
+	memset(p->thread.ptrace_bps, 0, sizeof(p->thread.ptrace_bps));
 
-	if (user_mode(regs)) {
-		childregs->regs[15] = usp;
-		ti->addr_limit = USER_DS;
-	} else {
-		childregs->regs[15] = (unsigned long)childregs;
+	childregs = task_pt_regs(p);
+	p->thread.sp = (unsigned long) childregs;
+	if (unlikely(p->flags & PF_KTHREAD)) {
+		memset(childregs, 0, sizeof(struct pt_regs));
+		p->thread.pc = (unsigned long) ret_from_kernel_thread;
+		childregs->regs[4] = arg;
+		childregs->regs[5] = usp;
+		childregs->sr = SR_MD;
+#if defined(CONFIG_SH_FPU)
+		childregs->sr |= SR_FD;
+#endif
 		ti->addr_limit = KERNEL_DS;
 		ti->status &= ~TS_USEDFPU;
 		p->fpu_counter = 0;
+		return 0;
 	}
+	*childregs = *regs;
+
+	childregs->regs[15] = usp;
+	ti->addr_limit = USER_DS;
 
 	if (clone_flags & CLONE_SETTLS)
 		childregs->gbr = childregs->regs[0];
 
 	childregs->regs[0] = 0; /* Set return value for child */
-
-	p->thread.sp = (unsigned long) childregs;
 	p->thread.pc = (unsigned long) ret_from_fork;
-
-	memset(p->thread.ptrace_bps, 0, sizeof(p->thread.ptrace_bps));
-
 	return 0;
 }