X-Git-Url: http://git.cascardo.info/?p=cascardo%2Flinux.git;a=blobdiff_plain;f=arch%2Fx86%2Fkernel%2Fprocess.c;h=28cea7802ecbc456ac3b7f8b8aeb44e0fee00ba0;hp=62c0b0ea2ce4483cb2ab29dc10492f877b2f93e7;hb=6727ad9e206cc08b80d8000a4d67f8417e53539d;hpb=2161a2a644a6d33a29d68395518d103ed805758f

diff --git a/arch/x86/kernel/process.c b/arch/x86/kernel/process.c
index 62c0b0ea2ce4..28cea7802ecb 100644
--- a/arch/x86/kernel/process.c
+++ b/arch/x86/kernel/process.c
@@ -32,6 +32,7 @@
 #include <asm/tlbflush.h>
 #include <asm/mce.h>
 #include <asm/vm86.h>
+#include <asm/switch_to.h>
 
 /*
  * per-CPU TSS segments. Threads are completely 'soft' on Linux,
@@ -301,7 +302,7 @@ void arch_cpu_idle(void)
 /*
  * We use this if we don't have any better idle routine..
  */
-void default_idle(void)
+void __cpuidle default_idle(void)
 {
 	trace_cpu_idle_rcuidle(1, smp_processor_id());
 	safe_halt();
@@ -416,7 +417,7 @@ static int prefer_mwait_c1_over_halt(const struct cpuinfo_x86 *c)
  * with interrupts enabled and no flags, which is backwards compatible with the
  * original MWAIT implementation.
  */
-static void mwait_idle(void)
+static __cpuidle void mwait_idle(void)
 {
 	if (!current_set_polling_and_test()) {
 		trace_cpu_idle_rcuidle(1, smp_processor_id());
@@ -512,6 +513,17 @@ unsigned long arch_randomize_brk(struct mm_struct *mm)
 	return randomize_range(mm->brk, range_end, 0) ? : mm->brk;
 }
 
+/*
+ * Return saved PC of a blocked thread.
+ * What is this good for? it will be always the scheduler or ret_from_fork.
+ */
+unsigned long thread_saved_pc(struct task_struct *tsk)
+{
+	struct inactive_task_frame *frame =
+		(struct inactive_task_frame *) READ_ONCE(tsk->thread.sp);
+	return READ_ONCE_NOCHECK(frame->ret_addr);
+}
+
 /*
  * Called from fs/proc with a reference on @p to find the function
  * which called into schedule(). This needs to be done carefully
@@ -520,15 +532,18 @@ unsigned long arch_randomize_brk(struct mm_struct *mm)
  */
 unsigned long get_wchan(struct task_struct *p)
 {
-	unsigned long start, bottom, top, sp, fp, ip;
+	unsigned long start, bottom, top, sp, fp, ip, ret = 0;
 	int count = 0;
 
 	if (!p || p == current || p->state == TASK_RUNNING)
 		return 0;
 
+	if (!try_get_task_stack(p))
+		return 0;
+
 	start = (unsigned long)task_stack_page(p);
 	if (!start)
-		return 0;
+		goto out;
 
 	/*
 	 * Layout of the stack page:
@@ -537,9 +552,7 @@ unsigned long get_wchan(struct task_struct *p)
 	 * PADDING
 	 * ----------- top = topmax - TOP_OF_KERNEL_STACK_PADDING
 	 * stack
-	 * ----------- bottom = start + sizeof(thread_info)
-	 * thread_info
-	 * ----------- start
+	 * ----------- bottom = start
 	 *
 	 * The tasks stack pointer points at the location where the
 	 * framepointer is stored. The data on the stack is:
@@ -550,20 +563,25 @@ unsigned long get_wchan(struct task_struct *p)
 	 */
 	top = start + THREAD_SIZE - TOP_OF_KERNEL_STACK_PADDING;
 	top -= 2 * sizeof(unsigned long);
-	bottom = start + sizeof(struct thread_info);
+	bottom = start;
 
 	sp = READ_ONCE(p->thread.sp);
 	if (sp < bottom || sp > top)
-		return 0;
+		goto out;
 
-	fp = READ_ONCE_NOCHECK(*(unsigned long *)sp);
+	fp = READ_ONCE_NOCHECK(((struct inactive_task_frame *)sp)->bp);
 	do {
 		if (fp < bottom || fp > top)
-			return 0;
+			goto out;
 		ip = READ_ONCE_NOCHECK(*(unsigned long *)(fp + sizeof(unsigned long)));
-		if (!in_sched_functions(ip))
-			return ip;
+		if (!in_sched_functions(ip)) {
+			ret = ip;
+			goto out;
+		}
 		fp = READ_ONCE_NOCHECK(*(unsigned long *)fp);
 	} while (count++ < 16 && p->state != TASK_RUNNING);
-	return 0;
+
+out:
+	put_task_stack(p);
+	return ret;
 }