Linux-libre 4.3.2-gnu

1 files changed, 63 insertions, 0 deletions

diff --git a/arch/x86/kernel/process.c b/arch/x86/kernel/process.c
index c27cad726..9f7c21c22 100644
--- a/arch/x86/kernel/process.c
+++ b/arch/x86/kernel/process.c
@@ -29,6 +29,8 @@
 #include <asm/debugreg.h>
 #include <asm/nmi.h>
 #include <asm/tlbflush.h>
+#include <asm/mce.h>
+#include <asm/vm86.h>
 
 /*
  * per-CPU TSS segments. Threads are completely 'soft' on Linux,
@@ -82,6 +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);
 }
@@ -110,6 +115,8 @@ void exit_thread(void)
 		kfree(bp);
 	}
 
+	free_vm86(t);
+
 	fpu__drop(fpu);
 }
 
@@ -319,6 +326,7 @@ void stop_this_cpu(void *dummy)
 	 */
 	set_cpu_online(smp_processor_id(), false);
 	disable_local_APIC();
+	mcheck_cpu_clear(this_cpu_ptr(&cpu_info));
 
 	for (;;)
 		halt();
@@ -501,3 +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;
+}