[PATCH v2 1/8] arm64: stacktrace: simplify unwind_next_common()

Mark Rutland
2022-08-05T12:46:45Z

Currently unwind_next_common() takes a pointer to a stack_info which is
only ever used within unwind_next_common().

Make it a local variable and simplify callers.

There should be no functional change as a result of this patch.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Reviewed-by: Kalesh Singh <kaleshsingh@google.com>
Reviewed-by: Mark Brown <broonie@kernel.org>
Cc: Fuad Tabba <tabba@google.com>
Cc: Madhavan T. Venkataraman <madvenka@linux.microsoft.com>
Cc: Marc Zyngier <maz@kernel.org>
---
arch/arm64/include/asm/stacktrace/common.h | 12 ++++++------
arch/arm64/kernel/stacktrace.c | 3 +--
arch/arm64/kvm/hyp/nvhe/stacktrace.c | 4 +---
arch/arm64/kvm/stacktrace.c | 4 +---
4 files changed, 9 insertions(+), 14 deletions(-)

diff --git a/arch/arm64/include/asm/stacktrace/common.h b/arch/arm64/include/asm/stacktrace/common.h
index f58eb944c46fb..01dc9f44a24a7 100644
--- a/arch/arm64/include/asm/stacktrace/common.h
+++ b/arch/arm64/include/asm/stacktrace/common.h
@@ -140,27 +140,27 @@ typedef bool (*on_accessible_stack_fn)(const struct task_struct *tsk,
struct stack_info *info);

static inline int unwind_next_common(struct unwind_state *state,
- struct stack_info *info,
on_accessible_stack_fn accessible,
stack_trace_translate_fp_fn translate_fp)
{
+ struct stack_info info;
unsigned long fp = state->fp, kern_fp = fp;
struct task_struct *tsk = state->task;

if (fp & 0x7)
return -EINVAL;

- if (!accessible(tsk, fp, 16, info))
+ if (!accessible(tsk, fp, 16, &info))
return -EINVAL;

- if (test_bit(info->type, state->stacks_done))
+ if (test_bit(info.type, state->stacks_done))
return -EINVAL;

/*
* If fp is not from the current address space perform the necessary
* translation before dereferencing it to get the next fp.
*/
- if (translate_fp && !translate_fp(&kern_fp, info->type))
+ if (translate_fp && !translate_fp(&kern_fp, info.type))
return -EINVAL;

/*
@@ -177,7 +177,7 @@ static inline int unwind_next_common(struct unwind_state *state,
* stack to another, it's never valid to unwind back to that first
* stack.
*/
- if (info->type == state->prev_type) {
+ if (info.type == state->prev_type) {
if (fp <= state->prev_fp)
return -EINVAL;
} else {
@@ -191,7 +191,7 @@ static inline int unwind_next_common(struct unwind_state *state,
state->fp = READ_ONCE(*(unsigned long *)(kern_fp));
state->pc = READ_ONCE(*(unsigned long *)(kern_fp + 8));
state->prev_fp = fp;
- state->prev_type = info->type;
+ state->prev_type = info.type;

return 0;
}
diff --git a/arch/arm64/kernel/stacktrace.c b/arch/arm64/kernel/stacktrace.c
index ce190ee18a201..056fb045d0e0c 100644
--- a/arch/arm64/kernel/stacktrace.c
+++ b/arch/arm64/kernel/stacktrace.c
@@ -103,14 +103,13 @@ static int notrace unwind_next(struct unwind_state *state)
{
struct task_struct *tsk = state->task;
unsigned long fp = state->fp;
- struct stack_info info;
int err;

/* Final frame; nothing to unwind */
if (fp == (unsigned long)task_pt_regs(tsk)->stackframe)
return -ENOENT;

- err = unwind_next_common(state, &info, on_accessible_stack, NULL);
+ err = unwind_next_common(state, on_accessible_stack, NULL);
if (err)
return err;

diff --git a/arch/arm64/kvm/hyp/nvhe/stacktrace.c b/arch/arm64/kvm/hyp/nvhe/stacktrace.c
index 58f645ad66bcb..50a1fa6b5c044 100644
--- a/arch/arm64/kvm/hyp/nvhe/stacktrace.c
+++ b/arch/arm64/kvm/hyp/nvhe/stacktrace.c
@@ -71,9 +71,7 @@ static bool on_accessible_stack(const struct task_struct *tsk,

static int unwind_next(struct unwind_state *state)
{
- struct stack_info info;
-
- return unwind_next_common(state, &info, on_accessible_stack, NULL);
+ return unwind_next_common(state, on_accessible_stack, NULL);
}

static void notrace unwind(struct unwind_state *state,
diff --git a/arch/arm64/kvm/stacktrace.c b/arch/arm64/kvm/stacktrace.c
index 949d19d603fba..b9cf551d9d31d 100644
--- a/arch/arm64/kvm/stacktrace.c
+++ b/arch/arm64/kvm/stacktrace.c
@@ -97,9 +97,7 @@ static bool on_accessible_stack(const struct task_struct *tsk,

static int unwind_next(struct unwind_state *state)
{
- struct stack_info info;
-
- return unwind_next_common(state, &info, on_accessible_stack,
+ return unwind_next_common(state, on_accessible_stack,
kvm_nvhe_stack_kern_va);
}

--
2.30.2