[PATCHv3,2/3] arm64: stacktrace: Factor out backtrace initialisation

Commit Message

Mark Rutland July 2, 2019, 1:07 p.m. UTC

From: Dave Martin <[e-mail]>

Some common code is required by each stacktrace user to initialise
struct stackframe before the first call to unwind_frame().

In preparation for adding to the common code, this patch factors it
out into a separate function start_backtrace(), and modifies the
stacktrace callers appropriately.

No functional change.

Signed-off-by: Dave Martin <[e-mail]>
[Mark: drop tsk argument, update more callsites]
Signed-off-by: Mark Rutland <[e-mail]>
Reviewed-by: James Morse <[e-mail]>
---
 arch/arm64/include/asm/stacktrace.h | 10 ++++++++++
 arch/arm64/kernel/perf_callchain.c  |  7 +------
 arch/arm64/kernel/process.c         |  7 ++-----
 arch/arm64/kernel/return_address.c  |  9 +++------
 arch/arm64/kernel/stacktrace.c      | 19 ++++++-------------
 arch/arm64/kernel/time.c            |  7 ++-----
 arch/arm64/kernel/traps.c           | 13 ++++++-------
 7 files changed, 30 insertions(+), 42 deletions(-)

Patch

diff --git a/arch/arm64/include/asm/stacktrace.h b/arch/arm64/include/asm/stacktrace.h
index 4dd569592e65..18f90bf1385c 100644
--- a/arch/arm64/include/asm/stacktrace.h
+++ b/arch/arm64/include/asm/stacktrace.h
@@ -142,4 +142,14 @@  static inline bool on_accessible_stack(const struct task_struct *tsk,
 	return false;
 }
 
+static inline void start_backtrace(struct stackframe *frame,
+				   unsigned long fp, unsigned long pc)
+{
+	frame->fp = fp;
+	frame->pc = pc;
+#ifdef CONFIG_FUNCTION_GRAPH_TRACER
+	frame->graph = 0;
+#endif
+}
+
 #endif	/* __ASM_STACKTRACE_H */
diff --git a/arch/arm64/kernel/perf_callchain.c b/arch/arm64/kernel/perf_callchain.c
index 61d983f5756f..35d024735869 100644
--- a/arch/arm64/kernel/perf_callchain.c
+++ b/arch/arm64/kernel/perf_callchain.c
@@ -165,12 +165,7 @@  void perf_callchain_kernel(struct perf_callchain_entry_ctx *entry,
 		return;
 	}
 
-	frame.fp = regs->regs[29];
-	frame.pc = regs->pc;
-#ifdef CONFIG_FUNCTION_GRAPH_TRACER
-	frame.graph = 0;
-#endif
-
+	start_backtrace(&frame, regs->regs[29], regs->pc);
 	walk_stackframe(current, &frame, callchain_trace, entry);
 }
 
diff --git a/arch/arm64/kernel/process.c b/arch/arm64/kernel/process.c
index 58efc3727778..46d6b21630a2 100644
--- a/arch/arm64/kernel/process.c
+++ b/arch/arm64/kernel/process.c
@@ -509,11 +509,8 @@  unsigned long get_wchan(struct task_struct *p)
 	if (!stack_page)
 		return 0;
 
-	frame.fp = thread_saved_fp(p);
-	frame.pc = thread_saved_pc(p);
-#ifdef CONFIG_FUNCTION_GRAPH_TRACER
-	frame.graph = 0;
-#endif
+	start_backtrace(&frame, thread_saved_fp(p), thread_saved_pc(p));
+
 	do {
 		if (unwind_frame(p, &frame))
 			goto out;
diff --git a/arch/arm64/kernel/return_address.c b/arch/arm64/kernel/return_address.c
index 53c40196b607..1b25321c7bf3 100644
--- a/arch/arm64/kernel/return_address.c
+++ b/arch/arm64/kernel/return_address.c
@@ -41,12 +41,9 @@  void *return_address(unsigned int level)
 	data.level = level + 2;
 	data.addr = NULL;
 
-	frame.fp = (unsigned long)__builtin_frame_address(0);
-	frame.pc = (unsigned long)return_address; /* dummy */
-#ifdef CONFIG_FUNCTION_GRAPH_TRACER
-	frame.graph = 0;
-#endif
-
+	start_backtrace(&frame,
+			(unsigned long)__builtin_frame_address(0),
+			(unsigned long)return_address);
 	walk_stackframe(current, &frame, save_return_addr, &data);
 
 	if (!data.level)
diff --git a/arch/arm64/kernel/stacktrace.c b/arch/arm64/kernel/stacktrace.c
index b00ec7d483d1..e5338216deaa 100644
--- a/arch/arm64/kernel/stacktrace.c
+++ b/arch/arm64/kernel/stacktrace.c
@@ -133,12 +133,7 @@  void save_stack_trace_regs(struct pt_regs *regs, struct stack_trace *trace)
 	data.skip = trace->skip;
 	data.no_sched_functions = 0;
 
-	frame.fp = regs->regs[29];
-	frame.pc = regs->pc;
-#ifdef CONFIG_FUNCTION_GRAPH_TRACER
-	frame.graph = 0;
-#endif
-
+	start_backtrace(&frame, regs->regs[29], regs->pc);
 	walk_stackframe(current, &frame, save_trace, &data);
 }
 EXPORT_SYMBOL_GPL(save_stack_trace_regs);
@@ -157,17 +152,15 @@  static noinline void __save_stack_trace(struct task_struct *tsk,
 	data.no_sched_functions = nosched;
 
 	if (tsk != current) {
-		frame.fp = thread_saved_fp(tsk);
-		frame.pc = thread_saved_pc(tsk);
+		start_backtrace(&frame, thread_saved_fp(tsk),
+				thread_saved_pc(tsk));
 	} else {
 		/* We don't want this function nor the caller */
 		data.skip += 2;
-		frame.fp = (unsigned long)__builtin_frame_address(0);
-		frame.pc = (unsigned long)__save_stack_trace;
+		start_backtrace(&frame,
+				(unsigned long)__builtin_frame_address(0),
+				(unsigned long)__save_stack_trace);
 	}
-#ifdef CONFIG_FUNCTION_GRAPH_TRACER
-	frame.graph = 0;
-#endif
 
 	walk_stackframe(tsk, &frame, save_trace, &data);
 
diff --git a/arch/arm64/kernel/time.c b/arch/arm64/kernel/time.c
index a777ae90044d..6af8d976a2d8 100644
--- a/arch/arm64/kernel/time.c
+++ b/arch/arm64/kernel/time.c
@@ -49,11 +49,8 @@  unsigned long profile_pc(struct pt_regs *regs)
 	if (!in_lock_functions(regs->pc))
 		return regs->pc;
 
-	frame.fp = regs->regs[29];
-	frame.pc = regs->pc;
-#ifdef CONFIG_FUNCTION_GRAPH_TRACER
-	frame.graph = 0;
-#endif
+	start_backtrace(&frame, regs->regs[29], regs->pc);
+
 	do {
 		int ret = unwind_frame(NULL, &frame);
 		if (ret < 0)
diff --git a/arch/arm64/kernel/traps.c b/arch/arm64/kernel/traps.c
index 8a395523adcf..44810d5aab49 100644
--- a/arch/arm64/kernel/traps.c
+++ b/arch/arm64/kernel/traps.c
@@ -111,18 +111,17 @@  void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk)
 		return;
 
 	if (tsk == current) {
-		frame.fp = (unsigned long)__builtin_frame_address(0);
-		frame.pc = (unsigned long)dump_backtrace;
+		start_backtrace(&frame,
+				(unsigned long)__builtin_frame_address(0),
+				(unsigned long)dump_backtrace);
 	} else {
 		/*
 		 * task blocked in __switch_to
 		 */
-		frame.fp = thread_saved_fp(tsk);
-		frame.pc = thread_saved_pc(tsk);
+		start_backtrace(&frame,
+				thread_saved_fp(tsk),
+				thread_saved_pc(tsk));
 	}
-#ifdef CONFIG_FUNCTION_GRAPH_TRACER
-	frame.graph = 0;
-#endif
 
 	printk("Call trace:\n");
 	do {