Commit 95c632f4 authored by Ingo Molnar's avatar Ingo Molnar

Merge remote-tracking branch 'tglx/x86/urgent' into x86/urgent

Pick up the WCHAN fixes from Thomas.
Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parents 4ac86a6d 7ba78053
......@@ -506,3 +506,58 @@ unsigned long arch_randomize_brk(struct mm_struct *mm)
return randomize_range(mm->brk, range_end, 0) ? : mm->brk;
}
/*
* Called from fs/proc with a reference on @p to find the function
* which called into schedule(). This needs to be done carefully
* because the task might wake up and we might look at a stack
* changing under us.
*/
unsigned long get_wchan(struct task_struct *p)
{
unsigned long start, bottom, top, sp, fp, ip;
int count = 0;
if (!p || p == current || p->state == TASK_RUNNING)
return 0;
start = (unsigned long)task_stack_page(p);
if (!start)
return 0;
/*
* Layout of the stack page:
*
* ----------- topmax = start + THREAD_SIZE - sizeof(unsigned long)
* PADDING
* ----------- top = topmax - TOP_OF_KERNEL_STACK_PADDING
* stack
* ----------- bottom = start + sizeof(thread_info)
* thread_info
* ----------- start
*
* The tasks stack pointer points at the location where the
* framepointer is stored. The data on the stack is:
* ... IP FP ... IP FP
*
* We need to read FP and IP, so we need to adjust the upper
* bound by another unsigned long.
*/
top = start + THREAD_SIZE - TOP_OF_KERNEL_STACK_PADDING;
top -= 2 * sizeof(unsigned long);
bottom = start + sizeof(struct thread_info);
sp = READ_ONCE(p->thread.sp);
if (sp < bottom || sp > top)
return 0;
fp = READ_ONCE(*(unsigned long *)sp);
do {
if (fp < bottom || fp > top)
return 0;
ip = READ_ONCE(*(unsigned long *)(fp + sizeof(unsigned long)));
if (!in_sched_functions(ip))
return ip;
fp = READ_ONCE(*(unsigned long *)fp);
} while (count++ < 16 && p->state != TASK_RUNNING);
return 0;
}
......@@ -324,31 +324,3 @@ __switch_to(struct task_struct *prev_p, struct task_struct *next_p)
return prev_p;
}
#define top_esp (THREAD_SIZE - sizeof(unsigned long))
#define top_ebp (THREAD_SIZE - 2*sizeof(unsigned long))
unsigned long get_wchan(struct task_struct *p)
{
unsigned long bp, sp, ip;
unsigned long stack_page;
int count = 0;
if (!p || p == current || p->state == TASK_RUNNING)
return 0;
stack_page = (unsigned long)task_stack_page(p);
sp = p->thread.sp;
if (!stack_page || sp < stack_page || sp > top_esp+stack_page)
return 0;
/* include/asm-i386/system.h:switch_to() pushes bp last. */
bp = *(unsigned long *) sp;
do {
if (bp < stack_page || bp > top_ebp+stack_page)
return 0;
ip = *(unsigned long *) (bp+4);
if (!in_sched_functions(ip))
return ip;
bp = *(unsigned long *) bp;
} while (count++ < 16);
return 0;
}
......@@ -499,30 +499,6 @@ void set_personality_ia32(bool x32)
}
EXPORT_SYMBOL_GPL(set_personality_ia32);
unsigned long get_wchan(struct task_struct *p)
{
unsigned long stack;
u64 fp, ip;
int count = 0;
if (!p || p == current || p->state == TASK_RUNNING)
return 0;
stack = (unsigned long)task_stack_page(p);
if (p->thread.sp < stack || p->thread.sp >= stack+THREAD_SIZE)
return 0;
fp = *(u64 *)(p->thread.sp);
do {
if (fp < (unsigned long)stack ||
fp >= (unsigned long)stack+THREAD_SIZE)
return 0;
ip = *(u64 *)(fp+8);
if (!in_sched_functions(ip))
return ip;
fp = *(u64 *)fp;
} while (count++ < 16);
return 0;
}
long do_arch_prctl(struct task_struct *task, int code, unsigned long addr)
{
int ret = 0;
......
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