powerpc: split ret_from_fork
... and get rid of in-kernel syscalls in kernel_thread()
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c
index 1a1f2dd..3b06898 100644
--- a/arch/powerpc/kernel/process.c
+++ b/arch/powerpc/kernel/process.c
@@ -734,30 +734,39 @@
extern unsigned long dscr_default; /* defined in arch/powerpc/kernel/sysfs.c */
int copy_thread(unsigned long clone_flags, unsigned long usp,
- unsigned long unused, struct task_struct *p,
+ unsigned long arg, struct task_struct *p,
struct pt_regs *regs)
{
struct pt_regs *childregs, *kregs;
extern void ret_from_fork(void);
+ extern void ret_from_kernel_thread(void);
+ void (*f)(void);
unsigned long sp = (unsigned long)task_stack_page(p) + THREAD_SIZE;
- CHECK_FULL_REGS(regs);
/* Copy registers */
sp -= sizeof(struct pt_regs);
childregs = (struct pt_regs *) sp;
- *childregs = *regs;
- if ((childregs->msr & MSR_PR) == 0) {
+ if (!regs) {
/* for kernel thread, set `current' and stackptr in new task */
+ memset(childregs, 0, sizeof(struct pt_regs));
childregs->gpr[1] = sp + sizeof(struct pt_regs);
-#ifdef CONFIG_PPC32
- childregs->gpr[2] = (unsigned long) p;
-#else
+#ifdef CONFIG_PPC64
+ childregs->gpr[14] = *(unsigned long *)usp;
+ childregs->gpr[2] = ((unsigned long *)usp)[1],
clear_tsk_thread_flag(p, TIF_32BIT);
+#else
+ childregs->gpr[14] = usp; /* function */
+ childregs->gpr[2] = (unsigned long) p;
#endif
+ childregs->gpr[15] = arg;
p->thread.regs = NULL; /* no user register state */
+ f = ret_from_kernel_thread;
} else {
+ CHECK_FULL_REGS(regs);
+ *childregs = *regs;
childregs->gpr[1] = usp;
p->thread.regs = childregs;
+ childregs->gpr[3] = 0; /* Result from fork() */
if (clone_flags & CLONE_SETTLS) {
#ifdef CONFIG_PPC64
if (!is_32bit_task())
@@ -766,8 +775,9 @@
#endif
childregs->gpr[2] = childregs->gpr[6];
}
+
+ f = ret_from_fork;
}
- childregs->gpr[3] = 0; /* Result from fork() */
sp -= STACK_FRAME_OVERHEAD;
/*
@@ -806,19 +816,17 @@
p->thread.dscr = current->thread.dscr;
}
#endif
-
/*
* The PPC64 ABI makes use of a TOC to contain function
* pointers. The function (ret_from_except) is actually a pointer
* to the TOC entry. The first entry is a pointer to the actual
* function.
- */
+ */
#ifdef CONFIG_PPC64
- kregs->nip = *((unsigned long *)ret_from_fork);
+ kregs->nip = *((unsigned long *)f);
#else
- kregs->nip = (unsigned long)ret_from_fork;
+ kregs->nip = (unsigned long)f;
#endif
-
return 0;
}