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hexagon: kernel_thread()/kernel_execve() conversion

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introduce sane current_pt_regs(), use it in syscalls where needed.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This commit is contained in:
Al Viro
2012-10-18 22:45:24 -04:00
父節點 ddffeb8c4d
當前提交 9952185554
共有 7 個文件被更改，包括 46 次插入 和 98 次删除
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102
arch/hexagon/kernel/process.c
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@@ -25,33 +25,6 @@
#include <linux/uaccess.h>
#include <linux/slab.h>
/*
* Kernel thread creation. The desired kernel function is "wrapped"
* in the kernel_thread_helper function, which does cleanup
* afterwards.
*/
static void __noreturn kernel_thread_helper(void *arg, int (*fn)(void *))
{
do_exit(fn(arg));
}
int kernel_thread(int (*fn)(void *), void *arg, unsigned long flags)
{
struct pt_regs regs;
memset(&regs, 0, sizeof(regs));
/*
* Yes, we're exploting illicit knowledge of the ABI here.
*/
regs.r00 = (unsigned long) arg;
regs.r01 = (unsigned long) fn;
pt_set_elr(&regs, (unsigned long)kernel_thread_helper);
pt_set_kmode(&regs);
return do_fork(flags|CLONE_VM|CLONE_UNTRACED, 0, &regs, 0, NULL, NULL);
}
EXPORT_SYMBOL(kernel_thread);
/*
* Program thread launch. Often defined as a macro in processor.h,
* but we're shooting for a small footprint and it's not an inner-loop
@@ -114,7 +87,7 @@ unsigned long thread_saved_pc(struct task_struct *tsk)
* Copy architecture-specific thread state
*/
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 thread_info *ti = task_thread_info(p);
@@ -125,61 +98,50 @@ int copy_thread(unsigned long clone_flags, unsigned long usp,
childregs = (struct pt_regs *) (((unsigned long) ti + THREAD_SIZE) -
sizeof(*childregs));
memcpy(childregs, regs, sizeof(*childregs));
ti->regs = childregs;
/*
* Establish kernel stack pointer and initial PC for new thread
* Note that unlike the usual situation, we do not copy the
* parent's callee-saved here; those are in pt_regs and whatever
* we leave here will be overridden on return to userland.
*/
ss = (struct hexagon_switch_stack *) ((unsigned long) childregs -
sizeof(*ss));
ss->lr = (unsigned long)ret_from_fork;
p->thread.switch_sp = ss;
/* If User mode thread, set pt_reg stack pointer as per parameter */
if (user_mode(childregs)) {
pt_set_rte_sp(childregs, usp);
/* Child sees zero return value */
childregs->r00 = 0;
/*
* The clone syscall has the C signature:
* int [r0] clone(int flags [r0],
* void *child_frame [r1],
* void *parent_tid [r2],
* void *child_tid [r3],
* void *thread_control_block [r4]);
* ugp is used to provide TLS support.
*/
if (clone_flags & CLONE_SETTLS)
childregs->ugp = childregs->r04;
/*
* Parent sees new pid -- not necessary, not even possible at
* this point in the fork process
* Might also want to set things like ti->addr_limit
*/
} else {
/*
* If kernel thread, resume stack is kernel stack base.
* Note that this is pointer arithmetic on pt_regs *
*/
pt_set_rte_sp(childregs, (unsigned long)(childregs + 1));
/*
* We need the current thread_info fast path pointer
* set up in pt_regs. The register to be used is
* parametric for assembler code, but the mechanism
* doesn't drop neatly into C. Needs to be fixed.
*/
childregs->THREADINFO_REG = (unsigned long) ti;
if (unlikely(p->flags & PF_KTHREAD)) {
memset(childregs, 0, sizeof(struct pt_regs));
/* r24 <- fn, r25 <- arg */
ss->r2524 = usp | ((u64)arg << 32);
pt_set_kmode(childregs);
return 0;
}
memcpy(childregs, regs, sizeof(*childregs));
ss->r2524 = 0;
pt_set_rte_sp(childregs, usp);
/* Child sees zero return value */
childregs->r00 = 0;
/*
* thread_info pointer is pulled out of task_struct "stack"
* field on switch_to.
* The clone syscall has the C signature:
* int [r0] clone(int flags [r0],
* void *child_frame [r1],
* void *parent_tid [r2],
* void *child_tid [r3],
* void *thread_control_block [r4]);
* ugp is used to provide TLS support.
*/
if (clone_flags & CLONE_SETTLS)
childregs->ugp = childregs->r04;
/*
* Parent sees new pid -- not necessary, not even possible at
* this point in the fork process
* Might also want to set things like ti->addr_limit
*/
p->stack = (void *)ti;
return 0;
}