mn10300: convert to generic kernel_thread()

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

arch/mn10300/Kconfig

@@ -8,6 +8,7 @@ config MN10300
 	select HAVE_ARCH_KGDB
 	select HAVE_NMI_WATCHDOG if MN10300_WD_TIMER
 	select GENERIC_CLOCKEVENTS
+	select GENERIC_KERNEL_THREAD
 
 config AM33_2
 	def_bool n

arch/mn10300/include/asm/processor.h

@@ -132,11 +132,6 @@ static inline void start_thread(struct pt_regs *regs,
 /* 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.
  */

arch/mn10300/kernel/process.c

@@ -161,24 +161,6 @@ void show_regs(struct pt_regs *regs)
 {
 }
 
-/*
- * create a kernel thread
- */
-int kernel_thread(int (*fn)(void *), void *arg, unsigned long flags)
-{
-	struct pt_regs regs = {
-		.a0 = (unsigned long) fn;
-		.d0 = (unsigned long) arg;
-	};
-
-	local_save_flags(regs.epsw);
-	regs.epsw |= EPSW_IE | EPSW_IM_7;
-
-	/* Ok, create the new process.. */
-	return do_fork(flags | CLONE_VM | CLONE_UNTRACED, 0, &regs, 0,
-		       NULL, NULL);
-}
-
 /*
  * free current thread data structures etc..
  */
@@ -232,30 +214,35 @@ int copy_thread(unsigned long clone_flags,
 	/* allocate the userspace exception frame and set it up */
 	c_ksp -= sizeof(struct pt_regs);
 	c_regs = (struct pt_regs *) c_ksp;
+	c_ksp -= 12; /* allocate function call ABI slack */
 
+	/* set up things up so the scheduler can start the new task */
 	p->thread.uregs = c_regs;
+	ti->frame	= c_regs;
+	p->thread.a3	= (unsigned long) c_regs;
+	p->thread.sp	= c_ksp;
+	p->thread.wchan	= p->thread.pc;
+	p->thread.usp	= c_usp;
+
+	if (unlikely(!kregs)) {
+		memset(c_regs, 0, sizeof(struct pt_regs));
+		c_regs->a0 = c_usp; /* function */
+		c_regs->d0 = ustk_size; /* argument */
+		local_save_flags(c_regs->epsw);
+		c_regs->epsw |= EPSW_IE | EPSW_IM_7;
+		p->thread.pc	= (unsigned long) ret_from_kernel_thread;
+		return 0;
+	}
 	*c_regs = *kregs;
 	c_regs->sp = c_usp;
 	c_regs->epsw &= ~EPSW_FE; /* my FPU */
 
-	c_ksp -= 12; /* allocate function call ABI slack */
-
 	/* the new TLS pointer is passed in as arg #5 to sys_clone() */
 	if (clone_flags & CLONE_SETTLS)
 		c_regs->e2 = current_frame()->d3;
 
-	if (unlikely(!user_mode(kregs)))
-		p->thread.pc	= (unsigned long) ret_from_kernel_thread;
-	else
 	p->thread.pc	= (unsigned long) ret_from_fork;
 
-	/* set up things up so the scheduler can start the new task */
-	ti->frame	= c_regs;
-	p->thread.a3	= (unsigned long) c_regs;
-	p->thread.sp	= c_ksp;
-	p->thread.wchan	= p->thread.pc;
-	p->thread.usp	= c_usp;
-
 	return 0;
 }