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Diffstat (limited to 'arch/arc/kernel/stacktrace.c')
-rw-r--r--arch/arc/kernel/stacktrace.c56
1 files changed, 31 insertions, 25 deletions
diff --git a/arch/arc/kernel/stacktrace.c b/arch/arc/kernel/stacktrace.c
index b23986f98450..f73da203b170 100644
--- a/arch/arc/kernel/stacktrace.c
+++ b/arch/arc/kernel/stacktrace.c
@@ -38,15 +38,27 @@
#ifdef CONFIG_ARC_DW2_UNWIND
-static void seed_unwind_frame_info(struct task_struct *tsk,
- struct pt_regs *regs,
- struct unwind_frame_info *frame_info)
+static int
+seed_unwind_frame_info(struct task_struct *tsk, struct pt_regs *regs,
+ struct unwind_frame_info *frame_info)
{
- /*
- * synchronous unwinding (e.g. dump_stack)
- * - uses current values of SP and friends
- */
- if (tsk == NULL && regs == NULL) {
+ if (regs) {
+ /*
+ * Asynchronous unwinding of intr/exception
+ * - Just uses the pt_regs passed
+ */
+ frame_info->task = tsk;
+
+ frame_info->regs.r27 = regs->fp;
+ frame_info->regs.r28 = regs->sp;
+ frame_info->regs.r31 = regs->blink;
+ frame_info->regs.r63 = regs->ret;
+ frame_info->call_frame = 0;
+ } else if (tsk == NULL || tsk == current) {
+ /*
+ * synchronous unwinding (e.g. dump_stack)
+ * - uses current values of SP and friends
+ */
unsigned long fp, sp, blink, ret;
frame_info->task = current;
@@ -63,13 +75,17 @@ static void seed_unwind_frame_info(struct task_struct *tsk,
frame_info->regs.r31 = blink;
frame_info->regs.r63 = ret;
frame_info->call_frame = 0;
- } else if (regs == NULL) {
+ } else {
/*
- * Asynchronous unwinding of sleeping task
- * - Gets SP etc from task's pt_regs (saved bottom of kernel
- * mode stack of task)
+ * Asynchronous unwinding of a likely sleeping task
+ * - first ensure it is actually sleeping
+ * - if so, it will be in __switch_to, kernel mode SP of task
+ * is safe-kept and BLINK at a well known location in there
*/
+ if (tsk->state == TASK_RUNNING)
+ return -1;
+
frame_info->task = tsk;
frame_info->regs.r27 = TSK_K_FP(tsk);
@@ -90,19 +106,8 @@ static void seed_unwind_frame_info(struct task_struct *tsk,
frame_info->regs.r28 += 60;
frame_info->call_frame = 0;
- } else {
- /*
- * Asynchronous unwinding of intr/exception
- * - Just uses the pt_regs passed
- */
- frame_info->task = tsk;
-
- frame_info->regs.r27 = regs->fp;
- frame_info->regs.r28 = regs->sp;
- frame_info->regs.r31 = regs->blink;
- frame_info->regs.r63 = regs->ret;
- frame_info->call_frame = 0;
}
+ return 0;
}
#endif
@@ -116,7 +121,8 @@ arc_unwind_core(struct task_struct *tsk, struct pt_regs *regs,
unsigned int address;
struct unwind_frame_info frame_info;
- seed_unwind_frame_info(tsk, regs, &frame_info);
+ if (seed_unwind_frame_info(tsk, regs, &frame_info))
+ return 0;
while (1) {
address = UNW_PC(&frame_info);