diff options
author | Daniel Vetter <daniel.vetter@ffwll.ch> | 2015-11-23 09:04:05 +0100 |
---|---|---|
committer | Daniel Vetter <daniel.vetter@ffwll.ch> | 2015-11-23 09:04:05 +0100 |
commit | 92907cbbef8625bb3998d1eb385fc88f23c97a3f (patch) | |
tree | 15626ff9287e37c3cb81c7286d6db5a7fd77c854 /arch/x86/kernel/process.c | |
parent | 15fbfccfe92c62ae8d1ecc647c44157ed01ac02e (diff) | |
parent | 1ec218373b8ebda821aec00bb156a9c94fad9cd4 (diff) |
Merge tag 'v4.4-rc2' into drm-intel-next-queued
Linux 4.4-rc2
Backmerge to get at
commit 1b0e3a049efe471c399674fd954500ce97438d30
Author: Imre Deak <imre.deak@intel.com>
Date: Thu Nov 5 23:04:11 2015 +0200
drm/i915/skl: disable display side power well support for now
so that we can proplery re-eanble skl power wells in -next.
Conflicts are just adjacent lines changed, except for intel_fbdev.c
where we need to interleave the changs. Nothing nefarious.
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Diffstat (limited to 'arch/x86/kernel/process.c')
-rw-r--r-- | arch/x86/kernel/process.c | 58 |
1 files changed, 58 insertions, 0 deletions
diff --git a/arch/x86/kernel/process.c b/arch/x86/kernel/process.c index 6d0e62ae8516..9f7c21c22477 100644 --- a/arch/x86/kernel/process.c +++ b/arch/x86/kernel/process.c @@ -84,6 +84,9 @@ EXPORT_SYMBOL_GPL(idle_notifier_unregister); int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src) { memcpy(dst, src, arch_task_struct_size); +#ifdef CONFIG_VM86 + dst->thread.vm86 = NULL; +#endif return fpu__copy(&dst->thread.fpu, &src->thread.fpu); } @@ -506,3 +509,58 @@ 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_NOCHECK(*(unsigned long *)sp); + do { + if (fp < bottom || fp > top) + return 0; + ip = READ_ONCE_NOCHECK(*(unsigned long *)(fp + sizeof(unsigned long))); + if (!in_sched_functions(ip)) + return ip; + fp = READ_ONCE_NOCHECK(*(unsigned long *)fp); + } while (count++ < 16 && p->state != TASK_RUNNING); + return 0; +} |