diff mbox series

[v8,3/8] ARM: ftrace: Enable HAVE_FUNCTION_GRAPH_RETVAL

Message ID 20230328134319.2185812-4-pengdonglin@sangfor.com.cn (mailing list archive)
State Superseded
Headers show
Series function_graph: Support recording and printing the return value of function | expand

Commit Message

pengdonglin March 28, 2023, 1:43 p.m. UTC 
The commit d4815c5d1bbd ("function_graph: Support recording and printing
the return value of function") laid the groundwork for the for the
funcgraph-retval, and this modification makes it available on the
ARM platform.

We introduce a new structure called fgraph_ret_regs for the ARM platform
to hold return registers and the frame pointer. We then fill its content
in the return_to_handler and pass its address to the function
ftrace_return_to_handler to record the return value.

Signed-off-by: Donglin Peng <pengdonglin@sangfor.com.cn>
---
v8:
 - Modify the control range of CONFIG_HAVE_FUNCTION_GRAPH_RETVAL
---
 arch/arm/Kconfig               |  1 +
 arch/arm/include/asm/ftrace.h  | 18 ++++++++++++++++++
 arch/arm/kernel/entry-ftrace.S |  6 +++++-
 3 files changed, 24 insertions(+), 1 deletion(-)

Comments

Russell King (Oracle) March 28, 2023, 2:02 p.m. UTC | #1 
On Tue, Mar 28, 2023 at 06:43:14AM -0700, Donglin Peng wrote:
> The commit d4815c5d1bbd ("function_graph: Support recording and printing
> the return value of function") laid the groundwork for the for the
> funcgraph-retval, and this modification makes it available on the
> ARM platform.
> 
> We introduce a new structure called fgraph_ret_regs for the ARM platform
> to hold return registers and the frame pointer. We then fill its content
> in the return_to_handler and pass its address to the function
> ftrace_return_to_handler to record the return value.
> 
> Signed-off-by: Donglin Peng <pengdonglin@sangfor.com.cn>
> ---
> v8:
>  - Modify the control range of CONFIG_HAVE_FUNCTION_GRAPH_RETVAL
> ---
>  arch/arm/Kconfig               |  1 +
>  arch/arm/include/asm/ftrace.h  | 18 ++++++++++++++++++
>  arch/arm/kernel/entry-ftrace.S |  6 +++++-
>  3 files changed, 24 insertions(+), 1 deletion(-)
> 
> diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
> index e24a9820e12f..73061379855a 100644
> --- a/arch/arm/Kconfig
> +++ b/arch/arm/Kconfig
> @@ -98,6 +98,7 @@ config ARM
>  	select HAVE_FAST_GUP if ARM_LPAE
>  	select HAVE_FTRACE_MCOUNT_RECORD if !XIP_KERNEL
>  	select HAVE_FUNCTION_ERROR_INJECTION
> +	select HAVE_FUNCTION_GRAPH_RETVAL if HAVE_FUNCTION_GRAPH_TRACER
>  	select HAVE_FUNCTION_GRAPH_TRACER
>  	select HAVE_FUNCTION_TRACER if !XIP_KERNEL
>  	select HAVE_GCC_PLUGINS
> diff --git a/arch/arm/include/asm/ftrace.h b/arch/arm/include/asm/ftrace.h
> index 7e9251ca29fe..2ab4bee21d79 100644
> --- a/arch/arm/include/asm/ftrace.h
> +++ b/arch/arm/include/asm/ftrace.h
> @@ -77,4 +77,22 @@ static inline bool arch_syscall_match_sym_name(const char *sym,
>  
>  #endif /* ifndef __ASSEMBLY__ */
>  
> +
> +#ifndef __ASSEMBLY__
> +struct fgraph_ret_regs {
> +	unsigned long regs[4];
> +	unsigned long fp;
> +};
> +
> +static inline unsigned long fgraph_ret_regs_return_value(struct fgraph_ret_regs *ret_regs)
> +{
> +	return ret_regs->regs[0];
> +}
> +
> +static inline unsigned long fgraph_ret_regs_frame_pointer(struct fgraph_ret_regs *ret_regs)
> +{
> +	return ret_regs->fp;
> +}
> +#endif
> +
>  #endif /* _ASM_ARM_FTRACE */
> diff --git a/arch/arm/kernel/entry-ftrace.S b/arch/arm/kernel/entry-ftrace.S
> index 3e7bcaca5e07..5f1e74555b25 100644
> --- a/arch/arm/kernel/entry-ftrace.S
> +++ b/arch/arm/kernel/entry-ftrace.S
> @@ -257,11 +257,15 @@ ENDPROC(ftrace_graph_regs_caller)
>  
>  #ifdef CONFIG_FUNCTION_GRAPH_TRACER
>  ENTRY(return_to_handler)
> +	sub	sp, sp, #4
>  	stmdb	sp!, {r0-r3}
> -	add	r0, sp, #16		@ sp at exit of instrumented routine
> +	add	r0, sp, #20		@ sp at exit of instrumented routine
> +	str	r0, [sp, #16]
> +	mov	r0, sp

1) EABI wants the stack to be aligned to 8 bytes.
2) We can do better than this.

	mov	ip, sp
	stmdb	sp!, {r0-r3, ip, lr}
	mov	r0, sp

>  	bl	ftrace_return_to_handler
>  	mov	lr, r0			@ r0 has real ret addr
>  	ldmia	sp!, {r0-r3}

	ldmia	sp, {r0-r3}		@ since we need to manually adjust sp,

> +	add	sp, sp, #4		@ skip fp

	add	sp, sp, #4 * 6		@ restore stack pointer here

>  	ret	lr
>  ENDPROC(return_to_handler)
>  #endif
> -- 
> 2.25.1
> 
> 
> _______________________________________________
> linux-arm-kernel mailing list
> linux-arm-kernel@lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
>
pengdonglin March 29, 2023, 1:15 a.m. UTC | #2 
On 2023/3/28 22:02, Russell King (Oracle) wrote:
> On Tue, Mar 28, 2023 at 06:43:14AM -0700, Donglin Peng wrote:
>> The commit d4815c5d1bbd ("function_graph: Support recording and printing
>> the return value of function") laid the groundwork for the for the
>> funcgraph-retval, and this modification makes it available on the
>> ARM platform.
>>
>> We introduce a new structure called fgraph_ret_regs for the ARM platform
>> to hold return registers and the frame pointer. We then fill its content
>> in the return_to_handler and pass its address to the function
>> ftrace_return_to_handler to record the return value.
>>
>> Signed-off-by: Donglin Peng <pengdonglin@sangfor.com.cn>
>> ---
>> v8:
>>   - Modify the control range of CONFIG_HAVE_FUNCTION_GRAPH_RETVAL
>> ---
>>   arch/arm/Kconfig               |  1 +
>>   arch/arm/include/asm/ftrace.h  | 18 ++++++++++++++++++
>>   arch/arm/kernel/entry-ftrace.S |  6 +++++-
>>   3 files changed, 24 insertions(+), 1 deletion(-)
>>
>> diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
>> index e24a9820e12f..73061379855a 100644
>> --- a/arch/arm/Kconfig
>> +++ b/arch/arm/Kconfig
>> @@ -98,6 +98,7 @@ config ARM
>>   	select HAVE_FAST_GUP if ARM_LPAE
>>   	select HAVE_FTRACE_MCOUNT_RECORD if !XIP_KERNEL
>>   	select HAVE_FUNCTION_ERROR_INJECTION
>> +	select HAVE_FUNCTION_GRAPH_RETVAL if HAVE_FUNCTION_GRAPH_TRACER
>>   	select HAVE_FUNCTION_GRAPH_TRACER
>>   	select HAVE_FUNCTION_TRACER if !XIP_KERNEL
>>   	select HAVE_GCC_PLUGINS
>> diff --git a/arch/arm/include/asm/ftrace.h b/arch/arm/include/asm/ftrace.h
>> index 7e9251ca29fe..2ab4bee21d79 100644
>> --- a/arch/arm/include/asm/ftrace.h
>> +++ b/arch/arm/include/asm/ftrace.h
>> @@ -77,4 +77,22 @@ static inline bool arch_syscall_match_sym_name(const char *sym,
>>   
>>   #endif /* ifndef __ASSEMBLY__ */
>>   
>> +
>> +#ifndef __ASSEMBLY__
>> +struct fgraph_ret_regs {
>> +	unsigned long regs[4];
>> +	unsigned long fp;
>> +};
>> +
>> +static inline unsigned long fgraph_ret_regs_return_value(struct fgraph_ret_regs *ret_regs)
>> +{
>> +	return ret_regs->regs[0];
>> +}
>> +
>> +static inline unsigned long fgraph_ret_regs_frame_pointer(struct fgraph_ret_regs *ret_regs)
>> +{
>> +	return ret_regs->fp;
>> +}
>> +#endif
>> +
>>   #endif /* _ASM_ARM_FTRACE */
>> diff --git a/arch/arm/kernel/entry-ftrace.S b/arch/arm/kernel/entry-ftrace.S
>> index 3e7bcaca5e07..5f1e74555b25 100644
>> --- a/arch/arm/kernel/entry-ftrace.S
>> +++ b/arch/arm/kernel/entry-ftrace.S
>> @@ -257,11 +257,15 @@ ENDPROC(ftrace_graph_regs_caller)
>>   
>>   #ifdef CONFIG_FUNCTION_GRAPH_TRACER
>>   ENTRY(return_to_handler)
>> +	sub	sp, sp, #4
>>   	stmdb	sp!, {r0-r3}
>> -	add	r0, sp, #16		@ sp at exit of instrumented routine
>> +	add	r0, sp, #20		@ sp at exit of instrumented routine
>> +	str	r0, [sp, #16]
>> +	mov	r0, sp
> 
> 1) EABI wants the stack to be aligned to 8 bytes.
> 2) We can do better than this.
> 
> 	mov	ip, sp
> 	stmdb	sp!, {r0-r3, ip, lr}
> 	mov	r0, sp

Great, I will modify it.

> 
>>   	bl	ftrace_return_to_handler
>>   	mov	lr, r0			@ r0 has real ret addr
>>   	ldmia	sp!, {r0-r3}
> 
> 	ldmia	sp, {r0-r3}		@ since we need to manually adjust sp,

Thanks, I will modify it.

> 
>> +	add	sp, sp, #4		@ skip fp
> 
> 	add	sp, sp, #4 * 6		@ restore stack pointer here

Thanks, I will modify it.

> 
>>   	ret	lr
>>   ENDPROC(return_to_handler)
>>   #endif
>> -- 
>> 2.25.1
>>
>>
>> _______________________________________________
>> 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/arm/Kconfig b/arch/arm/Kconfig
index e24a9820e12f..73061379855a 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -98,6 +98,7 @@  config ARM
 	select HAVE_FAST_GUP if ARM_LPAE
 	select HAVE_FTRACE_MCOUNT_RECORD if !XIP_KERNEL
 	select HAVE_FUNCTION_ERROR_INJECTION
+	select HAVE_FUNCTION_GRAPH_RETVAL if HAVE_FUNCTION_GRAPH_TRACER
 	select HAVE_FUNCTION_GRAPH_TRACER
 	select HAVE_FUNCTION_TRACER if !XIP_KERNEL
 	select HAVE_GCC_PLUGINS
diff --git a/arch/arm/include/asm/ftrace.h b/arch/arm/include/asm/ftrace.h
index 7e9251ca29fe..2ab4bee21d79 100644
--- a/arch/arm/include/asm/ftrace.h
+++ b/arch/arm/include/asm/ftrace.h
@@ -77,4 +77,22 @@  static inline bool arch_syscall_match_sym_name(const char *sym,
 
 #endif /* ifndef __ASSEMBLY__ */
 
+
+#ifndef __ASSEMBLY__
+struct fgraph_ret_regs {
+	unsigned long regs[4];
+	unsigned long fp;
+};
+
+static inline unsigned long fgraph_ret_regs_return_value(struct fgraph_ret_regs *ret_regs)
+{
+	return ret_regs->regs[0];
+}
+
+static inline unsigned long fgraph_ret_regs_frame_pointer(struct fgraph_ret_regs *ret_regs)
+{
+	return ret_regs->fp;
+}
+#endif
+
 #endif /* _ASM_ARM_FTRACE */
diff --git a/arch/arm/kernel/entry-ftrace.S b/arch/arm/kernel/entry-ftrace.S
index 3e7bcaca5e07..5f1e74555b25 100644
--- a/arch/arm/kernel/entry-ftrace.S
+++ b/arch/arm/kernel/entry-ftrace.S
@@ -257,11 +257,15 @@  ENDPROC(ftrace_graph_regs_caller)
 
 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
 ENTRY(return_to_handler)
+	sub	sp, sp, #4
 	stmdb	sp!, {r0-r3}
-	add	r0, sp, #16		@ sp at exit of instrumented routine
+	add	r0, sp, #20		@ sp at exit of instrumented routine
+	str	r0, [sp, #16]
+	mov	r0, sp
 	bl	ftrace_return_to_handler
 	mov	lr, r0			@ r0 has real ret addr
 	ldmia	sp!, {r0-r3}
+	add	sp, sp, #4		@ skip fp
 	ret	lr
 ENDPROC(return_to_handler)
 #endif