diff mbox series

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

Message ID 20190606125402.10229-3-mark.rutland@arm.com (mailing list archive)
State New, archived
Headers show
Series arm64: stacktrace: improve robustness | expand

Commit Message

Mark Rutland June 6, 2019, 12:54 p.m. UTC 
From: Dave Martin <Dave.Martin@arm.com>

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 <dave.martin@arm.com>
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
---
 arch/arm64/include/asm/stacktrace.h | 10 ++++++++++
 arch/arm64/kernel/process.c         |  6 +-----
 arch/arm64/kernel/time.c            |  6 +-----
 arch/arm64/kernel/traps.c           | 13 ++++++-------
 4 files changed, 18 insertions(+), 17 deletions(-)

Comments

Dave Martin June 21, 2019, 3:50 p.m. UTC | #1 
On Thu, Jun 06, 2019 at 01:54:01PM +0100, Mark Rutland wrote:
> From: Dave Martin <Dave.Martin@arm.com>
> 
> 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 <dave.martin@arm.com>
> Signed-off-by: Mark Rutland <mark.rutland@arm.com>

Ack (from memory you just added the CONFIG_FUNCTION_GRAPH_TRACER stuff,
the lack of which was causing build failures in my original version).

Have you added any new calls to start_backtrace() here?

Cheers
---Dave

> ---
>  arch/arm64/include/asm/stacktrace.h | 10 ++++++++++
>  arch/arm64/kernel/process.c         |  6 +-----
>  arch/arm64/kernel/time.c            |  6 +-----
>  arch/arm64/kernel/traps.c           | 13 ++++++-------
>  4 files changed, 18 insertions(+), 17 deletions(-)
> 
> 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/process.c b/arch/arm64/kernel/process.c
> index 3767fb21a5b8..122d88fccd13 100644
> --- a/arch/arm64/kernel/process.c
> +++ b/arch/arm64/kernel/process.c
> @@ -509,11 +509,7 @@ 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/time.c b/arch/arm64/kernel/time.c
> index a777ae90044d..aa3489f3a452 100644
> --- a/arch/arm64/kernel/time.c
> +++ b/arch/arm64/kernel/time.c
> @@ -49,11 +49,7 @@ 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 ade32046f3fe..8053bbed8776 100644
> --- a/arch/arm64/kernel/traps.c
> +++ b/arch/arm64/kernel/traps.c
> @@ -119,18 +119,17 @@ 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 {
> -- 
> 2.11.0
> 
> 
> _______________________________________________
> linux-arm-kernel mailing list
> linux-arm-kernel@lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
Mark Rutland June 28, 2019, 11:27 a.m. UTC | #2 
On Fri, Jun 21, 2019 at 04:50:48PM +0100, Dave Martin wrote:
> On Thu, Jun 06, 2019 at 01:54:01PM +0100, Mark Rutland wrote:
> > From: Dave Martin <Dave.Martin@arm.com>
> > 
> > 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 <dave.martin@arm.com>
> > Signed-off-by: Mark Rutland <mark.rutland@arm.com>
> 
> Ack (from memory you just added the CONFIG_FUNCTION_GRAPH_TRACER stuff,
> the lack of which was causing build failures in my original version).

You handled that in the version of the seires this was picked from [1].

I removed the tsk parameter, which now gets added in patch 3. I can
re-add that to this patch, or leave this as-is -- I have no strong
feelings either way.

> Have you added any new calls to start_backtrace() here?

No; I have not added any new calls.

Thanks,
Mark.

[1] http://lists.infradead.org/pipermail/linux-arm-kernel/2018-April/572687.html

> 
> Cheers
> ---Dave
> 
> > ---
> >  arch/arm64/include/asm/stacktrace.h | 10 ++++++++++
> >  arch/arm64/kernel/process.c         |  6 +-----
> >  arch/arm64/kernel/time.c            |  6 +-----
> >  arch/arm64/kernel/traps.c           | 13 ++++++-------
> >  4 files changed, 18 insertions(+), 17 deletions(-)
> > 
> > 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/process.c b/arch/arm64/kernel/process.c
> > index 3767fb21a5b8..122d88fccd13 100644
> > --- a/arch/arm64/kernel/process.c
> > +++ b/arch/arm64/kernel/process.c
> > @@ -509,11 +509,7 @@ 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/time.c b/arch/arm64/kernel/time.c
> > index a777ae90044d..aa3489f3a452 100644
> > --- a/arch/arm64/kernel/time.c
> > +++ b/arch/arm64/kernel/time.c
> > @@ -49,11 +49,7 @@ 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 ade32046f3fe..8053bbed8776 100644
> > --- a/arch/arm64/kernel/traps.c
> > +++ b/arch/arm64/kernel/traps.c
> > @@ -119,18 +119,17 @@ 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 {
> > -- 
> > 2.11.0
> > 
> > 
> > _______________________________________________
> > linux-arm-kernel mailing list
> > linux-arm-kernel@lists.infradead.org
> > http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
diff mbox series

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/process.c b/arch/arm64/kernel/process.c
index 3767fb21a5b8..122d88fccd13 100644
--- a/arch/arm64/kernel/process.c
+++ b/arch/arm64/kernel/process.c
@@ -509,11 +509,7 @@  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/time.c b/arch/arm64/kernel/time.c
index a777ae90044d..aa3489f3a452 100644
--- a/arch/arm64/kernel/time.c
+++ b/arch/arm64/kernel/time.c
@@ -49,11 +49,7 @@  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 ade32046f3fe..8053bbed8776 100644
--- a/arch/arm64/kernel/traps.c
+++ b/arch/arm64/kernel/traps.c
@@ -119,18 +119,17 @@  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 {