m68k: split ret_from_fork(), simplify kernel_thread() (533e6903) · Commits · e / devices / android_kernel_xiaomi_markw

arch/m68k/Kconfig

+1 −0

Original line number	Diff line number	Diff line
		@@ -13,6 +13,7 @@ config M68K
		select FPU if MMU
		select ARCH_WANT_IPC_PARSE_VERSION
		select ARCH_USES_GETTIMEOFFSET if MMU && !COLDFIRE
		select GENERIC_KERNEL_THREAD

		config RWSEM_GENERIC_SPINLOCK
		bool

arch/m68k/include/asm/processor.h

+0 −2

Original line number	Diff line number	Diff line
		@@ -154,8 +154,6 @@ static inline void release_thread(struct task_struct *dead_task)
		{
		}

		extern int kernel_thread(int (fn)(void ), void * arg, unsigned long flags);

		/*
		* Free current thread data structures etc..
		*/

arch/m68k/kernel/entry.S

+11 −0

Original line number	Diff line number	Diff line
		@@ -111,6 +111,17 @@ ENTRY(ret_from_fork)
		addql #4,%sp
		jra ret_from_exception

		ENTRY(ret_from_kernel_thread)
		\| a3 contains the kernel thread payload, d7 - its argument
		movel %d1,%sp@-
		jsr schedule_tail
		GET_CURRENT(%d0)
		movel %d7,(%sp)
		jsr %a3@
		addql #4,%sp
		movel %d0,(%sp)
		jra sys_exit

		#if defined(CONFIG_COLDFIRE) \|\| !defined(CONFIG_MMU)

		#ifdef TRAP_DBG_INTERRUPT

arch/m68k/kernel/process.c

+24 −60

Original line number	Diff line number	Diff line
		@@ -34,6 +34,7 @@


		asmlinkage void ret_from_fork(void);
		asmlinkage void ret_from_kernel_thread(void);


		/*
		@@ -120,51 +121,6 @@ void show_regs(struct pt_regs * regs)
		printk("USP: %08lx\n", rdusp());
		}

		/*
		* Create a kernel thread
		*/
		int kernel_thread(int (fn)(void ), void * arg, unsigned long flags)
		{
		int pid;
		mm_segment_t fs;

		fs = get_fs();
		set_fs (KERNEL_DS);

		{
		register long retval __asm__ ("d0");
		register long clone_arg __asm__ ("d1") = flags \| CLONE_VM \| CLONE_UNTRACED;

		retval = __NR_clone;
		__asm__ __volatile__
		("clrl %%d2\n\t"
		"trap #0\n\t" /* Linux/m68k system call */
		"tstl %0\n\t" /* child or parent */
		"jne 1f\n\t" /* parent - jump */
		#ifdef CONFIG_MMU
		"lea %%sp@(%c7),%6\n\t" /* reload current */
		"movel %6@,%6\n\t"
		#endif
		"movel %3,%%sp@-\n\t" /* push argument */
		"jsr %4@\n\t" /* call fn */
		"movel %0,%%d1\n\t" /* pass exit value */
		"movel %2,%%d0\n\t" /* exit */
		"trap #0\n"
		"1:"
		: "+d" (retval)
		: "i" (__NR_clone), "i" (__NR_exit),
		"r" (arg), "a" (fn), "d" (clone_arg), "r" (current),
		"i" (-THREAD_SIZE)
		: "d2");

		pid = retval;
		}

		set_fs (fs);
		return pid;
		}
		EXPORT_SYMBOL(kernel_thread);

		void flush_thread(void)
		{
		current->thread.fs = __USER_DS;
		@@ -216,30 +172,18 @@ asmlinkage int m68k_clone(struct pt_regs *regs)
		}

		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;
		struct switch_stack * childstack, *stack;
		unsigned long *retp;
		struct switch_stack *childstack;

		childregs = (struct pt_regs *) (task_stack_page(p) + THREAD_SIZE) - 1;

		childregs = regs;
		childregs->d0 = 0;

		retp = ((unsigned long *) regs);
		stack = ((struct switch_stack *) retp) - 1;

		childstack = ((struct switch_stack *) childregs) - 1;
		childstack = stack;
		childstack->retpc = (unsigned long)ret_from_fork;

		p->thread.usp = usp;
		p->thread.ksp = (unsigned long)childstack;

		if (clone_flags & CLONE_SETTLS)
		task_thread_info(p)->tp_value = regs->d5;
		p->thread.esp0 = (unsigned long)childregs;

		/*
		* Must save the current SFC/DFC value, NOT the value when
		@@ -247,6 +191,26 @@ int copy_thread(unsigned long clone_flags, unsigned long usp,
		*/
		p->thread.fs = get_fs().seg;

		if (unlikely(!regs)) {
		/* kernel thread */
		memset(childstack, 0,
		sizeof(struct switch_stack) + sizeof(struct pt_regs));
		childregs->sr = PS_S;
		childstack->a3 = usp; /* function */
		childstack->d7 = arg;
		childstack->retpc = (unsigned long)ret_from_kernel_thread;
		p->thread.usp = 0;
		return 0;
		}
		childregs = regs;
		childregs->d0 = 0;

		childstack = ((struct switch_stack ) regs)[-1];
		childstack->retpc = (unsigned long)ret_from_fork;

		if (clone_flags & CLONE_SETTLS)
		task_thread_info(p)->tp_value = regs->d5;

		#ifdef CONFIG_FPU
		if (!FPU_IS_EMU) {
		/* Copy the current fpu state */