[PATCH 3/3] arm64: stacktrace: Convert to ARCH_STACKWALK

Mark Brown
2020-07-15T20:45:04Z

Historically architectures have had duplicated code in their stack trace
implementations for filtering what gets traced. In order to avoid this
duplication some generic code has been provided using a new interface
arch_stack_walk(), enabled by selecting ARCH_STACKWALK in Kconfig, which
factors all this out into the generic stack trace code. Convert arm64
to use this common infrastructure.

Signed-off-by: Mark Brown <broonie@kernel.org>
---
arch/arm64/Kconfig | 1 +
arch/arm64/kernel/stacktrace.c | 79 ++++------------------------------
2 files changed, 9 insertions(+), 71 deletions(-)

diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index 5d4f02b3dfe9..6ed4b6c6df95 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -29,6 +29,7 @@ config ARM64
select ARCH_HAS_SETUP_DMA_OPS
select ARCH_HAS_SET_DIRECT_MAP
select ARCH_HAS_SET_MEMORY
+ select ARCH_STACKWALK
select ARCH_HAS_STRICT_KERNEL_RWX
select ARCH_HAS_STRICT_MODULE_RWX
select ARCH_HAS_SYNC_DMA_FOR_DEVICE
diff --git a/arch/arm64/kernel/stacktrace.c b/arch/arm64/kernel/stacktrace.c
index 743cf11fbfca..a33fba048954 100644
--- a/arch/arm64/kernel/stacktrace.c
+++ b/arch/arm64/kernel/stacktrace.c
@@ -133,82 +133,19 @@ void notrace walk_stackframe(struct task_struct *tsk, struct stackframe *frame,
NOKPROBE_SYMBOL(walk_stackframe);

#ifdef CONFIG_STACKTRACE
-struct stack_trace_data {
- struct stack_trace *trace;
- unsigned int no_sched_functions;
- unsigned int skip;
-};

-static bool save_trace(void *d, unsigned long addr)
+void arch_stack_walk(stack_trace_consume_fn consume_entry, void *cookie,
+ struct task_struct *task, struct pt_regs *regs)
{
- struct stack_trace_data *data = d;
- struct stack_trace *trace = data->trace;
-
- if (data->no_sched_functions && in_sched_functions(addr))
- return false;
- if (data->skip) {
- data->skip--;
- return false;
- }
-
- trace->entries[trace->nr_entries++] = addr;
-
- return trace->nr_entries >= trace->max_entries;
-}
-
-void save_stack_trace_regs(struct pt_regs *regs, struct stack_trace *trace)
-{
- struct stack_trace_data data;
- struct stackframe frame;
-
- data.trace = trace;
- data.skip = trace->skip;
- data.no_sched_functions = 0;
-
- start_backtrace(&frame, regs->regs[29], regs->pc);
- walk_stackframe(current, &frame, save_trace, &data);
-}
-EXPORT_SYMBOL_GPL(save_stack_trace_regs);
-
-static noinline void __save_stack_trace(struct task_struct *tsk,
- struct stack_trace *trace, unsigned int nosched)
-{
- struct stack_trace_data data;
struct stackframe frame;

- if (!try_get_task_stack(tsk))
- return;
+ if (regs)
+ start_backtrace(&frame, regs->regs[29], regs->pc);
+ else
+ start_backtrace(&frame, thread_saved_fp(task),
+ thread_saved_pc(task));

- data.trace = trace;
- data.skip = trace->skip;
- data.no_sched_functions = nosched;
-
- if (tsk != current) {
- start_backtrace(&frame, thread_saved_fp(tsk),
- thread_saved_pc(tsk));
- } else {
- /* We don't want this function nor the caller */
- data.skip += 2;
- start_backtrace(&frame,
- (unsigned long)__builtin_frame_address(0),
- (unsigned long)__save_stack_trace);
- }
-
- walk_stackframe(tsk, &frame, save_trace, &data);
-
- put_task_stack(tsk);
-}
-
-void save_stack_trace_tsk(struct task_struct *tsk, struct stack_trace *trace)
-{
- __save_stack_trace(tsk, trace, 1);
-}
-EXPORT_SYMBOL_GPL(save_stack_trace_tsk);
-
-void save_stack_trace(struct stack_trace *trace)
-{
- __save_stack_trace(current, trace, 0);
+ walk_stackframe(task, &frame, consume_entry, cookie);
}

-EXPORT_SYMBOL_GPL(save_stack_trace);
#endif
--
2.20.1