Commit 5fc57df2 authored by Mark Brown's avatar Mark Brown Committed by Will Deacon
Browse files

arm64: stacktrace: Convert to ARCH_STACKWALK 



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: default avatarMark Brown <broonie@kernel.org>
Reviewed-by: default avatarMiroslav Benes <mbenes@suse.cz>
Link: https://lore.kernel.org/r/20200914153409.25097-4-broonie@kernel.org


Signed-off-by: default avatarWill Deacon <will@kernel.org>
parent baa2cd41

arch/arm64/Kconfig

+1 −0
Original line number Diff line number Diff line
@@ -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

arch/arm64/kernel/stacktrace.c

+10 −69
Original line number Diff line number Diff line
@@ -133,82 +133,23 @@ 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;



	if (regs)

		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;



	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;

	else if (task == current)

		start_backtrace(&frame,

				(unsigned long)__builtin_frame_address(0),

				(unsigned long)__save_stack_trace);

	}



	walk_stackframe(tsk, &frame, save_trace, &data);

				(unsigned long)arch_stack_walk);

	else

		start_backtrace(&frame, thread_saved_fp(task),

				thread_saved_pc(task));



	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

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