[PATCH v2 1/2] ftrace: cleanup ftrace_graph

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* [PATCH v2 1/2] ftrace: cleanup ftrace_graph_caller enable and disable
@ 2022-02-23  9:01 Chengming Zhou
  2022-02-23  9:01 ` [PATCH v2 2/2] arm64/ftrace: Make function graph use ftrace directly Chengming Zhou
  2022-02-24  1:17 ` [PATCH v2 1/2] ftrace: cleanup ftrace_graph_caller enable and disable Steven Rostedt
  0 siblings, 2 replies; 4+ messages in thread
From: Chengming Zhou @ 2022-02-23  9:01 UTC (permalink / raw)
  To: rostedt, mingo, catalin.marinas, will, broonie, mark.rutland,
	tglx, bp, dave.hansen
  Cc: linux-arm-kernel, x86, linux-kernel, songmuchun, qirui.001,
	Chengming Zhou

The ftrace_enable_ftrace_graph_caller() and
ftrace_disable_ftrace_graph_caller() are used to do special
hooks for graph tracer, which are not needed on some ARCHs
when DYNAMIC_FTRACE_WITH_[ARGS,REGS] enabled. So introduce
weak version in Ftrace core code to cleanup them.

And fix the incorrect comment in that two #endif, which should
match the previous #ifdef and #ifndef.

Signed-off-by: Chengming Zhou <zhouchengming@bytedance.com>
---
 arch/x86/kernel/ftrace.c | 14 ++------------
 kernel/trace/ftrace.c    | 20 ++++++++++++++++++++
 2 files changed, 22 insertions(+), 12 deletions(-)

diff --git a/arch/x86/kernel/ftrace.c b/arch/x86/kernel/ftrace.c
index 7cc540e6de0c..c119ef7a9295 100644
--- a/arch/x86/kernel/ftrace.c
+++ b/arch/x86/kernel/ftrace.c
@@ -615,18 +615,8 @@ int ftrace_disable_ftrace_graph_caller(void)
 
 	return ftrace_mod_jmp(ip, &ftrace_stub);
 }
-#else /* !CONFIG_HAVE_DYNAMIC_FTRACE_WITH_ARGS */
-int ftrace_enable_ftrace_graph_caller(void)
-{
-	return 0;
-}
-
-int ftrace_disable_ftrace_graph_caller(void)
-{
-	return 0;
-}
-#endif /* CONFIG_HAVE_DYNAMIC_FTRACE_WITH_ARGS */
-#endif /* !CONFIG_DYNAMIC_FTRACE */
+#endif /* !CONFIG_HAVE_DYNAMIC_FTRACE_WITH_ARGS */
+#endif /* CONFIG_DYNAMIC_FTRACE */
 
 /*
  * Hook the return address and push it in the stack of return addrs
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index f9feb197b2da..60ae009e6684 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -2704,6 +2704,26 @@ int __weak ftrace_arch_code_modify_post_process(void)
 	return 0;
 }
 
+#ifdef CONFIG_FUNCTION_GRAPH_TRACER
+/*
+ * archs can override this function if they must do something
+ * to enable hook for graph tracer.
+ */
+int __weak ftrace_enable_ftrace_graph_caller(void)
+{
+	return 0;
+}
+
+/*
+ * archs can override this function if they must do something
+ * to disable hook for graph tracer.
+ */
+int __weak ftrace_disable_ftrace_graph_caller(void)
+{
+	return 0;
+}
+#endif
+
 void ftrace_modify_all_code(int command)
 {
 	int update = command & FTRACE_UPDATE_TRACE_FUNC;
-- 
2.20.1


^ permalink raw reply related	[flat|nested] 4+ messages in thread

* [PATCH v2 2/2] arm64/ftrace: Make function graph use ftrace directly
  2022-02-23  9:01 [PATCH v2 1/2] ftrace: cleanup ftrace_graph_caller enable and disable Chengming Zhou
@ 2022-02-23  9:01 ` Chengming Zhou
  2022-02-24  1:17 ` [PATCH v2 1/2] ftrace: cleanup ftrace_graph_caller enable and disable Steven Rostedt
  1 sibling, 0 replies; 4+ messages in thread
From: Chengming Zhou @ 2022-02-23  9:01 UTC (permalink / raw)
  To: rostedt, mingo, catalin.marinas, will, broonie, mark.rutland,
	tglx, bp, dave.hansen
  Cc: linux-arm-kernel, x86, linux-kernel, songmuchun, qirui.001,
	Chengming Zhou

As we do in commit 0c0593b45c9b ("x86/ftrace: Make function graph
use ftrace directly"), we don't need special hook for graph tracer,
but instead we use graph_ops:func function to install return_hooker.

Since commit 3b23e4991fb6 ("arm64: implement ftrace with regs") add
implementation for FTRACE_WITH_REGS on arm64, we can easily adopt
the same cleanup on arm64. And this cleanup only changes the
FTRACE_WITH_REGS implementation, so the mcount-based implementation
is unaffected.

Signed-off-by: Chengming Zhou <zhouchengming@bytedance.com>
---
 arch/arm64/include/asm/ftrace.h  |  7 +++++++
 arch/arm64/kernel/entry-ftrace.S | 17 -----------------
 arch/arm64/kernel/ftrace.c       | 12 ++++++++++++
 3 files changed, 19 insertions(+), 17 deletions(-)

diff --git a/arch/arm64/include/asm/ftrace.h b/arch/arm64/include/asm/ftrace.h
index 1494cfa8639b..dbc45a4157fa 100644
--- a/arch/arm64/include/asm/ftrace.h
+++ b/arch/arm64/include/asm/ftrace.h
@@ -80,8 +80,15 @@ static inline unsigned long ftrace_call_adjust(unsigned long addr)
 
 #ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
 struct dyn_ftrace;
+struct ftrace_ops;
+struct ftrace_regs;
+
 int ftrace_init_nop(struct module *mod, struct dyn_ftrace *rec);
 #define ftrace_init_nop ftrace_init_nop
+
+void ftrace_graph_func(unsigned long ip, unsigned long parent_ip,
+		       struct ftrace_ops *op, struct ftrace_regs *fregs);
+#define ftrace_graph_func ftrace_graph_func
 #endif
 
 #define ftrace_return_address(n) return_address(n)
diff --git a/arch/arm64/kernel/entry-ftrace.S b/arch/arm64/kernel/entry-ftrace.S
index e535480a4069..d42a205ef625 100644
--- a/arch/arm64/kernel/entry-ftrace.S
+++ b/arch/arm64/kernel/entry-ftrace.S
@@ -97,12 +97,6 @@ SYM_CODE_START(ftrace_common)
 SYM_INNER_LABEL(ftrace_call, SYM_L_GLOBAL)
 	bl	ftrace_stub
 
-#ifdef CONFIG_FUNCTION_GRAPH_TRACER
-SYM_INNER_LABEL(ftrace_graph_call, SYM_L_GLOBAL) // ftrace_graph_caller();
-	nop				// If enabled, this will be replaced
-					// "b ftrace_graph_caller"
-#endif
-
 /*
  * At the callsite x0-x8 and x19-x30 were live. Any C code will have preserved
  * x19-x29 per the AAPCS, and we created frame records upon entry, so we need
@@ -127,17 +121,6 @@ ftrace_common_return:
 	ret	x9
 SYM_CODE_END(ftrace_common)
 
-#ifdef CONFIG_FUNCTION_GRAPH_TRACER
-SYM_CODE_START(ftrace_graph_caller)
-	ldr	x0, [sp, #S_PC]
-	sub	x0, x0, #AARCH64_INSN_SIZE	// ip (callsite's BL insn)
-	add	x1, sp, #S_LR			// parent_ip (callsite's LR)
-	ldr	x2, [sp, #PT_REGS_SIZE]	   	// parent fp (callsite's FP)
-	bl	prepare_ftrace_return
-	b	ftrace_common_return
-SYM_CODE_END(ftrace_graph_caller)
-#endif
-
 #else /* CONFIG_DYNAMIC_FTRACE_WITH_REGS */
 
 /*
diff --git a/arch/arm64/kernel/ftrace.c b/arch/arm64/kernel/ftrace.c
index 4506c4a90ac1..aeac174507a8 100644
--- a/arch/arm64/kernel/ftrace.c
+++ b/arch/arm64/kernel/ftrace.c
@@ -268,6 +268,17 @@ void prepare_ftrace_return(unsigned long self_addr, unsigned long *parent,
 }
 
 #ifdef CONFIG_DYNAMIC_FTRACE
+
+#ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
+void ftrace_graph_func(unsigned long ip, unsigned long parent_ip,
+		       struct ftrace_ops *op, struct ftrace_regs *fregs)
+{
+	struct pt_regs *regs = arch_ftrace_get_regs(fregs);
+	unsigned long *parent = (unsigned long *)&procedure_link_pointer(regs);
+
+	prepare_ftrace_return(ip, parent, frame_pointer(regs));
+}
+#else
 /*
  * Turn on/off the call to ftrace_graph_caller() in ftrace_caller()
  * depending on @enable.
@@ -297,5 +308,6 @@ int ftrace_disable_ftrace_graph_caller(void)
 {
 	return ftrace_modify_graph_caller(false);
 }
+#endif /* CONFIG_DYNAMIC_FTRACE_WITH_REGS */
 #endif /* CONFIG_DYNAMIC_FTRACE */
 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
-- 
2.20.1


^ permalink raw reply related	[flat|nested] 4+ messages in thread

* Re: [PATCH v2 1/2] ftrace: cleanup ftrace_graph_caller enable and disable
  2022-02-23  9:01 [PATCH v2 1/2] ftrace: cleanup ftrace_graph_caller enable and disable Chengming Zhou
  2022-02-23  9:01 ` [PATCH v2 2/2] arm64/ftrace: Make function graph use ftrace directly Chengming Zhou
@ 2022-02-24  1:17 ` Steven Rostedt
  2022-02-24  2:00   ` [External] " Chengming Zhou
  1 sibling, 1 reply; 4+ messages in thread
From: Steven Rostedt @ 2022-02-24  1:17 UTC (permalink / raw)
  To: Chengming Zhou
  Cc: mingo, catalin.marinas, will, broonie, mark.rutland, tglx, bp,
	dave.hansen, linux-arm-kernel, x86, linux-kernel, songmuchun,
	qirui.001

On Wed, 23 Feb 2022 17:01:31 +0800
Chengming Zhou <zhouchengming@bytedance.com> wrote:

> diff --git a/arch/x86/kernel/ftrace.c b/arch/x86/kernel/ftrace.c
> index 7cc540e6de0c..c119ef7a9295 100644
> --- a/arch/x86/kernel/ftrace.c
> +++ b/arch/x86/kernel/ftrace.c
> @@ -615,18 +615,8 @@ int ftrace_disable_ftrace_graph_caller(void)
>  
>  	return ftrace_mod_jmp(ip, &ftrace_stub);
>  }
> -#else /* !CONFIG_HAVE_DYNAMIC_FTRACE_WITH_ARGS */
> -int ftrace_enable_ftrace_graph_caller(void)
> -{
> -	return 0;
> -}
> -
> -int ftrace_disable_ftrace_graph_caller(void)
> -{
> -	return 0;
> -}
> -#endif /* CONFIG_HAVE_DYNAMIC_FTRACE_WITH_ARGS */
> -#endif /* !CONFIG_DYNAMIC_FTRACE */
> +#endif /* !CONFIG_HAVE_DYNAMIC_FTRACE_WITH_ARGS */
> +#endif /* CONFIG_DYNAMIC_FTRACE */

Since you are cleaning this up, and the above starts with:

#ifdef CONFIG_DYNAMIC_FTRACE

#ifndef CONFIG_HAVE_DYNAMIC_FTRACE_WITH_ARGS


They were separate because of the #else that you just removed. I would
recommend consolidate them into a single #ifdef:

#if defined(CONFIG_DYNAMIC_FTRACE) && !defined(CONFIG_HAVE_DYNAMIC_FTRACE_WITH_ARGS)

[..]

#endif /* CONFIG_DYNAMIC_FTRACE && !CONFIG_HAVE_DYNAMI_FTRACE_WITH_ARGS */


-- Steve


>  
>  /*
>   * Hook the return address and push it in the stack of return addrs
> diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
> index f9feb197b2da..60ae009e6684 100644

^ permalink raw reply	[flat|nested] 4+ messages in thread

* Re: [External] Re: [PATCH v2 1/2] ftrace: cleanup ftrace_graph_caller enable and disable
  2022-02-24  1:17 ` [PATCH v2 1/2] ftrace: cleanup ftrace_graph_caller enable and disable Steven Rostedt
@ 2022-02-24  2:00   ` Chengming Zhou
  0 siblings, 0 replies; 4+ messages in thread
From: Chengming Zhou @ 2022-02-24  2:00 UTC (permalink / raw)
  To: Steven Rostedt
  Cc: mingo, catalin.marinas, will, broonie, mark.rutland, tglx, bp,
	dave.hansen, linux-arm-kernel, x86, linux-kernel, songmuchun,
	qirui.001

On 2022/2/24 9:17 上午, Steven Rostedt wrote:
> On Wed, 23 Feb 2022 17:01:31 +0800
> Chengming Zhou <zhouchengming@bytedance.com> wrote:
> 
>> diff --git a/arch/x86/kernel/ftrace.c b/arch/x86/kernel/ftrace.c
>> index 7cc540e6de0c..c119ef7a9295 100644
>> --- a/arch/x86/kernel/ftrace.c
>> +++ b/arch/x86/kernel/ftrace.c
>> @@ -615,18 +615,8 @@ int ftrace_disable_ftrace_graph_caller(void)
>>  
>>  	return ftrace_mod_jmp(ip, &ftrace_stub);
>>  }
>> -#else /* !CONFIG_HAVE_DYNAMIC_FTRACE_WITH_ARGS */
>> -int ftrace_enable_ftrace_graph_caller(void)
>> -{
>> -	return 0;
>> -}
>> -
>> -int ftrace_disable_ftrace_graph_caller(void)
>> -{
>> -	return 0;
>> -}
>> -#endif /* CONFIG_HAVE_DYNAMIC_FTRACE_WITH_ARGS */
>> -#endif /* !CONFIG_DYNAMIC_FTRACE */
>> +#endif /* !CONFIG_HAVE_DYNAMIC_FTRACE_WITH_ARGS */
>> +#endif /* CONFIG_DYNAMIC_FTRACE */
> 
> Since you are cleaning this up, and the above starts with:
> 
> #ifdef CONFIG_DYNAMIC_FTRACE
> 
> #ifndef CONFIG_HAVE_DYNAMIC_FTRACE_WITH_ARGS
> 
> 
> They were separate because of the #else that you just removed. I would
> recommend consolidate them into a single #ifdef:
> 
> #if defined(CONFIG_DYNAMIC_FTRACE) && !defined(CONFIG_HAVE_DYNAMIC_FTRACE_WITH_ARGS)
> 
> [..]
> 
> #endif /* CONFIG_DYNAMIC_FTRACE && !CONFIG_HAVE_DYNAMI_FTRACE_WITH_ARGS */
> 

Good suggestion, this is better.

Thanks.

> 
> -- Steve
> 
> 
>>  
>>  /*
>>   * Hook the return address and push it in the stack of return addrs
>> diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
>> index f9feb197b2da..60ae009e6684 100644

^ permalink raw reply	[flat|nested] 4+ messages in thread

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2022-02-23  9:01 [PATCH v2 1/2] ftrace: cleanup ftrace_graph_caller enable and disable Chengming Zhou
2022-02-23  9:01 ` [PATCH v2 2/2] arm64/ftrace: Make function graph use ftrace directly Chengming Zhou
2022-02-24  1:17 ` [PATCH v2 1/2] ftrace: cleanup ftrace_graph_caller enable and disable Steven Rostedt
2022-02-24  2:00   ` [External] " Chengming Zhou

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