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powerpc: split ret_from_fork

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... and get rid of in-kernel syscalls in kernel_thread()

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This commit is contained in:
Al Viro 2012-09-12 18:32:42 -04:00
parent f322220d61
commit 58254e1002
8 changed files with 43 additions and 84 deletions
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1
arch/powerpc/Kconfig
View File

@ -139,6 +139,7 @@ config PPC
select GENERIC_CLOCKEVENTS
select GENERIC_STRNCPY_FROM_USER
select GENERIC_STRNLEN_USER
select GENERIC_KERNEL_THREAD
config EARLY_PRINTK
bool

3
arch/powerpc/include/asm/processor.h
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@ -74,9 +74,6 @@ struct task_struct;
void start_thread(struct pt_regs *regs, unsigned long fdptr, unsigned long sp);
void release_thread(struct task_struct *);
/* Create a new kernel thread. */
extern long kernel_thread(int (*fn)(void *), void *arg, unsigned long flags);
/* Lazy FPU handling on uni-processor */
extern struct task_struct *last_task_used_math;
extern struct task_struct *last_task_used_altivec;

11
arch/powerpc/kernel/entry_32.S
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@ -435,6 +435,17 @@ ret_from_fork:
li r3,0
b ret_from_syscall
.globl ret_from_kernel_thread
ret_from_kernel_thread:
REST_NVGPRS(r1)
bl schedule_tail
mtlr r14
mr r3,r15
PPC440EP_ERR42
blrl
li r3,0
b do_exit # no return
/* Traced system call support */
syscall_dotrace:
SAVE_NVGPRS(r1)

10
arch/powerpc/kernel/entry_64.S
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@ -370,6 +370,16 @@ _GLOBAL(ret_from_fork)
li r3,0
b syscall_exit
_GLOBAL(ret_from_kernel_thread)
bl .schedule_tail
REST_NVGPRS(r1)
REST_GPR(2,r1)
mtlr r14
mr r3,r15
blrl
li r3,0
b .do_exit # no return
.section ".toc","aw"
DSCR_DEFAULT:
.tc dscr_default[TC],dscr_default

33
arch/powerpc/kernel/misc_32.S
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@ -663,39 +663,6 @@ _GLOBAL(abs)
sub r3,r3,r4
blr
/*
* Create a kernel thread
* kernel_thread(fn, arg, flags)
*/
_GLOBAL(kernel_thread)
stwu r1,-16(r1)
stw r30,8(r1)
stw r31,12(r1)
mr r30,r3 /* function */
mr r31,r4 /* argument */
ori r3,r5,CLONE_VM /* flags */
oris r3,r3,CLONE_UNTRACED>>16
li r4,0 /* new sp (unused) */
li r0,__NR_clone
sc
bns+ 1f /* did system call indicate error? */
neg r3,r3 /* if so, make return code negative */
1: cmpwi 0,r3,0 /* parent or child? */
bne 2f /* return if parent */
li r0,0 /* make top-level stack frame */
stwu r0,-16(r1)
mtlr r30 /* fn addr in lr */
mr r3,r31 /* load arg and call fn */
PPC440EP_ERR42
blrl
li r0,__NR_exit /* exit if function returns */
li r3,0
sc
2: lwz r30,8(r1)
lwz r31,12(r1)
addi r1,r1,16
blr
#ifdef CONFIG_SMP
_GLOBAL(start_secondary_resume)
/* Reset stack */

34
arch/powerpc/kernel/misc_64.S
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@ -406,40 +406,6 @@ _GLOBAL(scom970_write)
#endif /* CONFIG_CPU_FREQ_PMAC64 || CONFIG_CPU_FREQ_MAPLE */
/*
* Create a kernel thread
* kernel_thread(fn, arg, flags)
*/
_GLOBAL(kernel_thread)
std r29,-24(r1)
std r30,-16(r1)
stdu r1,-STACK_FRAME_OVERHEAD(r1)
mr r29,r3
mr r30,r4
ori r3,r5,CLONE_VM /* flags */
oris r3,r3,(CLONE_UNTRACED>>16)
li r4,0 /* new sp (unused) */
li r0,__NR_clone
sc
bns+ 1f /* did system call indicate error? */
neg r3,r3 /* if so, make return code negative */
1: cmpdi 0,r3,0 /* parent or child? */
bne 2f /* return if parent */
li r0,0
stdu r0,-STACK_FRAME_OVERHEAD(r1)
ld r2,8(r29)
ld r29,0(r29)
mtlr r29 /* fn addr in lr */
mr r3,r30 /* load arg and call fn */
blrl
li r0,__NR_exit /* exit after child exits */
li r3,0
sc
2: addi r1,r1,STACK_FRAME_OVERHEAD
ld r29,-24(r1)
ld r30,-16(r1)
blr
/*
* disable_kernel_fp()
* Disable the FPU.

1
arch/powerpc/kernel/ppc_ksyms.c
View File

@ -94,7 +94,6 @@ EXPORT_SYMBOL(pci_dram_offset);
#endif /* CONFIG_PCI */
EXPORT_SYMBOL(start_thread);
EXPORT_SYMBOL(kernel_thread);
EXPORT_SYMBOL(giveup_fpu);
#ifdef CONFIG_ALTIVEC

34
arch/powerpc/kernel/process.c
View File

@ -734,30 +734,39 @@ int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src)
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 @@ int copy_thread(unsigned long clone_flags, unsigned long usp,
#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 @@ int copy_thread(unsigned long clone_flags, unsigned long usp,
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;
}