[PATCH v12 05/10] arm64: Copy unwind arguments to unwind_state

madvenka
2022-01-03T16:55:20Z

From: "Madhavan T. Venkataraman" <madvenka@linux.microsoft.com>

Copy the following arguments passed to arch_stack_walk() to unwind_state
so that they can be passed to unwind functions via unwind_state rather
than as separate arguments:

- task
- regs
- consume_entry
- cookie

Signed-off-by: Madhavan T. Venkataraman <madvenka@linux.microsoft.com>
---
arch/arm64/include/asm/stacktrace.h | 12 ++++++++
arch/arm64/kernel/stacktrace.c | 45 ++++++++++++++++-------------
2 files changed, 37 insertions(+), 20 deletions(-)

diff --git a/arch/arm64/include/asm/stacktrace.h b/arch/arm64/include/asm/stacktrace.h
index fc828c3c5dfd..322817d40a75 100644
--- a/arch/arm64/include/asm/stacktrace.h
+++ b/arch/arm64/include/asm/stacktrace.h
@@ -51,6 +51,14 @@ struct stack_info {
* @kr_cur: When KRETPOLINES is selected, holds the kretprobe instance
* associated with the most recently encountered replacement lr
* value.
+ *
+ * @task: Pointer to the task structure.
+ *
+ * @regs: Registers, if any.
+ *
+ * @consume_pc Consume PC function pointer.
+ *
+ * @cookie Argument to consume_pc().
*/
struct unwind_state {
unsigned long fp;
@@ -61,6 +69,10 @@ struct unwind_state {
#ifdef CONFIG_KRETPROBES
struct llist_node *kr_cur;
#endif
+ struct task_struct *task;
+ struct pt_regs *regs;
+ stack_trace_consume_fn consume_pc;
+ void *cookie;
};

extern void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk,
diff --git a/arch/arm64/kernel/stacktrace.c b/arch/arm64/kernel/stacktrace.c
index bd797e3f7789..3ecb8242caa5 100644
--- a/arch/arm64/kernel/stacktrace.c
+++ b/arch/arm64/kernel/stacktrace.c
@@ -33,8 +33,17 @@
*/

-static void unwind_init_common(struct unwind_state *state)
+static void unwind_init_common(struct unwind_state *state,
+ struct task_struct *task,
+ struct pt_regs *regs,
+ stack_trace_consume_fn consume_pc,
+ void *cookie)
{
+ state->task = task;
+ state->regs = regs;
+ state->consume_pc = consume_pc;
+ state->cookie = cookie;
+
#ifdef CONFIG_KRETPROBES
state->kr_cur = NULL;
#endif
@@ -56,11 +65,10 @@ static void unwind_init_common(struct unwind_state *state)
/*
* TODO: document requirements here.
*/
-static inline void unwind_init_regs(struct unwind_state *state,
- struct pt_regs *regs)
+static inline void unwind_init_regs(struct unwind_state *state)
{
- state->fp = regs->regs[29];
- state->pc = regs->pc;
+ state->fp = state->regs->regs[29];
+ state->pc = state->regs->pc;
}

/*
@@ -80,11 +88,10 @@ static __always_inline void unwind_init_current(struct unwind_state *state)
*
* The caller guarantees that the task is not running.
*/
-static inline void unwind_init_task(struct unwind_state *state,
- struct task_struct *task)
+static inline void unwind_init_task(struct unwind_state *state)
{
- state->fp = thread_saved_fp(task);
- state->pc = thread_saved_pc(task);
+ state->fp = thread_saved_fp(state->task);
+ state->pc = thread_saved_pc(state->task);
}

/*
@@ -94,9 +101,9 @@ static inline void unwind_init_task(struct unwind_state *state,
* records (e.g. a cycle), determined based on the location and fp value of A
* and the location (but not the fp value) of B.
*/
-static int notrace unwind_next(struct task_struct *tsk,
- struct unwind_state *state)
+static int notrace unwind_next(struct unwind_state *state)
{
+ struct task_struct *tsk = state->task;
unsigned long fp = state->fp;
struct stack_info info;

@@ -170,16 +177,14 @@ static int notrace unwind_next(struct task_struct *tsk,
}
NOKPROBE_SYMBOL(unwind_next);

-static void notrace unwind(struct task_struct *tsk,
- struct unwind_state *state,
- bool (*fn)(void *, unsigned long), void *data)
+static void notrace unwind(struct unwind_state *state)
{
while (1) {
int ret;

- if (!fn(data, state->pc))
+ if (!state->consume_pc(state->cookie, state->pc))
break;
- ret = unwind_next(tsk, state);
+ ret = unwind_next(state);
if (ret < 0)
break;
}
@@ -225,14 +230,14 @@ noinline notrace void arch_stack_walk(stack_trace_consume_fn consume_entry,
{
struct unwind_state state;

- unwind_init_common(&state);
+ unwind_init_common(&state, task, regs, consume_entry, cookie);

if (regs)
- unwind_init_regs(&state, regs);
+ unwind_init_regs(&state);
else if (task == current)
unwind_init_current(&state);
else
- unwind_init_task(&state, task);
+ unwind_init_task(&state);

- unwind(task, &state, consume_entry, cookie);
+ unwind(&state);
}
--
2.25.1