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m68k: split ret_from_fork(), simplify kernel_thread()

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Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This commit is contained in:
Al Viro 2012-09-16 12:05:09 -04:00
parent 0973c687e0
commit 533e6903be
4 changed files with 36 additions and 62 deletions
repo.diff.show_diff_stats Download patch file Download diff file Expand all files Collapse all files

1
arch/m68k/Kconfig
View file

@ -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

2
arch/m68k/include/asm/processor.h
View file

@ -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..
*/

11
arch/m68k/kernel/entry.S
View file

@ -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

84
arch/m68k/kernel/process.c
View file

@ -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 */