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Diffstat (limited to 'arch/s390/kernel/unwind_bc.c')
-rw-r--r--arch/s390/kernel/unwind_bc.c18
1 files changed, 13 insertions, 5 deletions
diff --git a/arch/s390/kernel/unwind_bc.c b/arch/s390/kernel/unwind_bc.c
index 8fc9daae47a2..a8204f952315 100644
--- a/arch/s390/kernel/unwind_bc.c
+++ b/arch/s390/kernel/unwind_bc.c
@@ -46,10 +46,15 @@ bool unwind_next_frame(struct unwind_state *state)
regs = state->regs;
if (unlikely(regs)) {
- sp = READ_ONCE_NOCHECK(regs->gprs[15]);
- if (unlikely(outside_of_stack(state, sp))) {
- if (!update_stack_info(state, sp))
- goto out_err;
+ if (state->reuse_sp) {
+ sp = state->sp;
+ state->reuse_sp = false;
+ } else {
+ sp = READ_ONCE_NOCHECK(regs->gprs[15]);
+ if (unlikely(outside_of_stack(state, sp))) {
+ if (!update_stack_info(state, sp))
+ goto out_err;
+ }
}
sf = (struct stack_frame *) sp;
ip = READ_ONCE_NOCHECK(sf->gprs[8]);
@@ -107,9 +112,9 @@ void __unwind_start(struct unwind_state *state, struct task_struct *task,
{
struct stack_info *info = &state->stack_info;
unsigned long *mask = &state->stack_mask;
+ bool reliable, reuse_sp;
struct stack_frame *sf;
unsigned long ip;
- bool reliable;
memset(state, 0, sizeof(*state));
state->task = task;
@@ -134,10 +139,12 @@ void __unwind_start(struct unwind_state *state, struct task_struct *task,
if (regs) {
ip = READ_ONCE_NOCHECK(regs->psw.addr);
reliable = true;
+ reuse_sp = true;
} else {
sf = (struct stack_frame *) sp;
ip = READ_ONCE_NOCHECK(sf->gprs[8]);
reliable = false;
+ reuse_sp = false;
}
#ifdef CONFIG_FUNCTION_GRAPH_TRACER
@@ -151,5 +158,6 @@ void __unwind_start(struct unwind_state *state, struct task_struct *task,
state->sp = sp;
state->ip = ip;
state->reliable = reliable;
+ state->reuse_sp = reuse_sp;
}
EXPORT_SYMBOL_GPL(__unwind_start);