Re: [PATCH v8 1/8] ftrace: make CALLER_ADDRx macros more generic

[AKASHI Takahiro <takahiro.akashi@linaro.org>]

Hi Will, Steven,

So sorry, I completely missed this message thread. I will submit a new patch (replacement of [1/8])
in the following e-mail.

-Takahiro AKASHI

On 05/03/2014 04:19 AM, Steven Rostedt wrote:
> On Wed, 30 Apr 2014 18:54:29 +0900
> AKASHI Takahiro <takahiro.akashi@linaro.org> wrote:
>
>> Most archs with HAVE_ARCH_CALLER_ADDR have the almost same definitions
>> of CALLER_ADDRx(n), and so put them into linux/ftrace.h.
>
> Please add a bit more to the change log. Like what you did. Something
> like:
>
> ----
> Most archs with HAVE_ARCH_CALLER_ADDR have pretty much the same
> definitions of CALLER_ADDRx(n). Instead of duplicating the code for all
> the archs, define a ftrace_return_address0() and
> ftrace_return_address(n) that can be overwritten by the archs if they
> need to do something different. Instead of 7 macros in every arch, we
> now only have at most 2 (and actually only 1 as
> ftrace_return_address0() should be the same for all archs).
>
> The CALLER_ADDRx(n) will now be defined in linux/ftrace.h and use the
> ftrace_return_address*(n?) macros. This removes a lot of the duplicate
> code.
> -----
>
> Use that if you want :-)
>
>
>>
>> Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org>
>> ---
>>   arch/arm/include/asm/ftrace.h      |   10 +---------
>>   arch/blackfin/include/asm/ftrace.h |   11 +----------
>>   arch/parisc/include/asm/ftrace.h   |   10 +---------
>>   arch/sh/include/asm/ftrace.h       |   10 +---------
>>   arch/xtensa/include/asm/ftrace.h   |   14 ++++----------
>>   include/linux/ftrace.h             |   34 ++++++++++++++++++----------------
>>   6 files changed, 26 insertions(+), 63 deletions(-)
>>
>> diff --git a/arch/arm/include/asm/ftrace.h b/arch/arm/include/asm/ftrace.h
>> index f89515a..eb577f4 100644
>> --- a/arch/arm/include/asm/ftrace.h
>> +++ b/arch/arm/include/asm/ftrace.h
>> @@ -52,15 +52,7 @@ extern inline void *return_address(unsigned int level)
>>
>>   #endif
>>
>> -#define HAVE_ARCH_CALLER_ADDR
>> -
>> -#define CALLER_ADDR0 ((unsigned long)__builtin_return_address(0))
>> -#define CALLER_ADDR1 ((unsigned long)return_address(1))
>> -#define CALLER_ADDR2 ((unsigned long)return_address(2))
>> -#define CALLER_ADDR3 ((unsigned long)return_address(3))
>> -#define CALLER_ADDR4 ((unsigned long)return_address(4))
>> -#define CALLER_ADDR5 ((unsigned long)return_address(5))
>> -#define CALLER_ADDR6 ((unsigned long)return_address(6))
>> +#define ftrace_return_addr(n) return_address(n)
>>
>>   #endif /* ifndef __ASSEMBLY__ */
>>
>> diff --git a/arch/blackfin/include/asm/ftrace.h b/arch/blackfin/include/asm/ftrace.h
>> index 8a02950..2f1c3c2 100644
>> --- a/arch/blackfin/include/asm/ftrace.h
>> +++ b/arch/blackfin/include/asm/ftrace.h
>> @@ -66,16 +66,7 @@ extern inline void *return_address(unsigned int level)
>>
>>   #endif /* CONFIG_FRAME_POINTER */
>>
>> -#define HAVE_ARCH_CALLER_ADDR
>> -
>> -/* inline function or macro may lead to unexpected result */
>> -#define CALLER_ADDR0 ((unsigned long)__builtin_return_address(0))
>> -#define CALLER_ADDR1 ((unsigned long)return_address(1))
>> -#define CALLER_ADDR2 ((unsigned long)return_address(2))
>> -#define CALLER_ADDR3 ((unsigned long)return_address(3))
>> -#define CALLER_ADDR4 ((unsigned long)return_address(4))
>> -#define CALLER_ADDR5 ((unsigned long)return_address(5))
>> -#define CALLER_ADDR6 ((unsigned long)return_address(6))
>> +#define ftrace_return_address(n) return_address(n)
>>
>>   #endif /* __ASSEMBLY__ */
>>
>> diff --git a/arch/parisc/include/asm/ftrace.h b/arch/parisc/include/asm/ftrace.h
>> index 72c0faf..544ed8e 100644
>> --- a/arch/parisc/include/asm/ftrace.h
>> +++ b/arch/parisc/include/asm/ftrace.h
>> @@ -24,15 +24,7 @@ extern void return_to_handler(void);
>>
>>   extern unsigned long return_address(unsigned int);
>>
>> -#define HAVE_ARCH_CALLER_ADDR
>> -
>> -#define CALLER_ADDR0 ((unsigned long)__builtin_return_address(0))
>> -#define CALLER_ADDR1 return_address(1)
>> -#define CALLER_ADDR2 return_address(2)
>> -#define CALLER_ADDR3 return_address(3)
>> -#define CALLER_ADDR4 return_address(4)
>> -#define CALLER_ADDR5 return_address(5)
>> -#define CALLER_ADDR6 return_address(6)
>> +#define ftrace_return_address(n) return_address(n)
>>
>>   #endif /* __ASSEMBLY__ */
>>
>> diff --git a/arch/sh/include/asm/ftrace.h b/arch/sh/include/asm/ftrace.h
>> index 13e9966..e79fb6e 100644
>> --- a/arch/sh/include/asm/ftrace.h
>> +++ b/arch/sh/include/asm/ftrace.h
>> @@ -40,15 +40,7 @@ static inline unsigned long ftrace_call_adjust(unsigned long addr)
>>   /* arch/sh/kernel/return_address.c */
>>   extern void *return_address(unsigned int);
>>
>> -#define HAVE_ARCH_CALLER_ADDR
>> -
>> -#define CALLER_ADDR0 ((unsigned long)__builtin_return_address(0))
>> -#define CALLER_ADDR1 ((unsigned long)return_address(1))
>> -#define CALLER_ADDR2 ((unsigned long)return_address(2))
>> -#define CALLER_ADDR3 ((unsigned long)return_address(3))
>> -#define CALLER_ADDR4 ((unsigned long)return_address(4))
>> -#define CALLER_ADDR5 ((unsigned long)return_address(5))
>> -#define CALLER_ADDR6 ((unsigned long)return_address(6))
>> +#define ftrace_return_address(n) return_address(n)
>>
>>   #endif /* __ASSEMBLY__ */
>>
>> diff --git a/arch/xtensa/include/asm/ftrace.h b/arch/xtensa/include/asm/ftrace.h
>> index 736b9d2..6c6d9a9 100644
>> --- a/arch/xtensa/include/asm/ftrace.h
>> +++ b/arch/xtensa/include/asm/ftrace.h
>> @@ -12,24 +12,18 @@
>>
>>   #include <asm/processor.h>
>>
>> -#define HAVE_ARCH_CALLER_ADDR
>>   #ifndef __ASSEMBLY__
>> -#define CALLER_ADDR0 ({ unsigned long a0, a1; \
>> +#define ftrace_return_address0 ({ unsigned long a0, a1; \
>>   		__asm__ __volatile__ ( \
>>   			"mov %0, a0\n" \
>>   			"mov %1, a1\n" \
>>   			: "=r"(a0), "=r"(a1)); \
>>   		MAKE_PC_FROM_RA(a0, a1); })
>> +
>>   #ifdef CONFIG_FRAME_POINTER
>>   extern unsigned long return_address(unsigned level);
>> -#define CALLER_ADDR1 return_address(1)
>> -#define CALLER_ADDR2 return_address(2)
>> -#define CALLER_ADDR3 return_address(3)
>> -#else /* CONFIG_FRAME_POINTER */
>> -#define CALLER_ADDR1 (0)
>> -#define CALLER_ADDR2 (0)
>> -#define CALLER_ADDR3 (0)
>> -#endif /* CONFIG_FRAME_POINTER */
>> +#define ftrace_return_address(n) return_address(n)
>
> I would add a comment here that states:
>
> /*
>   * #else !CONFIG_FRAME_POINTER
>   *
>   * Define CALLER_ADDRn (n > 0) to 0 is the default in linux/ftrace.h if
>   * ftrace_return_address(n) and CONFIG_FRAME_POINTER are not defined.
>   */
>
> Otherwise it looks like you are missing the #else statement.
>
>> +#endif
>>   #endif /* __ASSEMBLY__ */
>>
>>   #ifdef CONFIG_FUNCTION_TRACER
>> diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h
>> index 9212b01..18f1ae7 100644
>> --- a/include/linux/ftrace.h
>> +++ b/include/linux/ftrace.h
>> @@ -614,25 +614,27 @@ static inline void __ftrace_enabled_restore(int enabled)
>>   #endif
>>   }
>>
>> -#ifndef HAVE_ARCH_CALLER_ADDR
>> +/* All archs should have this, but we define it for consistency */
>
> The comment is a little confusing. I think it may be better stated as:
>
> /*
>   * All archs should be able to use __builtin_return_address(0) but
>   * we allow them to redefine it for consistency.
>   */
>
>> +#ifndef ftrace_return_address0
>> +# define ftrace_return_address0 __builtin_return_address(0)
>> +#endif
>> +
>> +/* Archs may use other ways for ADDR1 and beyond */
>
> How about:
>
> /* Not all archs can use __builtin_return_address(n) where n > 0 */
>
>> +#ifndef ftrace_return_address
>>   # ifdef CONFIG_FRAME_POINTER
>> -#  define CALLER_ADDR0 ((unsigned long)__builtin_return_address(0))
>> -#  define CALLER_ADDR1 ((unsigned long)__builtin_return_address(1))
>> -#  define CALLER_ADDR2 ((unsigned long)__builtin_return_address(2))
>> -#  define CALLER_ADDR3 ((unsigned long)__builtin_return_address(3))
>> -#  define CALLER_ADDR4 ((unsigned long)__builtin_return_address(4))
>> -#  define CALLER_ADDR5 ((unsigned long)__builtin_return_address(5))
>> -#  define CALLER_ADDR6 ((unsigned long)__builtin_return_address(6))
>> +#  define ftrace_return_address(n) __builtin_return_address(n)
>>   # else
>> -#  define CALLER_ADDR0 ((unsigned long)__builtin_return_address(0))
>> -#  define CALLER_ADDR1 0UL
>> -#  define CALLER_ADDR2 0UL
>> -#  define CALLER_ADDR3 0UL
>> -#  define CALLER_ADDR4 0UL
>> -#  define CALLER_ADDR5 0UL
>> -#  define CALLER_ADDR6 0UL
>> +#  define ftrace_return_address(n) 0UL
>>   # endif
>> -#endif /* ifndef HAVE_ARCH_CALLER_ADDR */
>> +#endif
>> +
>> +#define CALLER_ADDR0 ((unsigned long)ftrace_return_address0)
>> +#define CALLER_ADDR1 ((unsigned long)ftrace_return_address(1))
>> +#define CALLER_ADDR2 ((unsigned long)ftrace_return_address(2))
>> +#define CALLER_ADDR3 ((unsigned long)ftrace_return_address(3))
>> +#define CALLER_ADDR4 ((unsigned long)ftrace_return_address(4))
>> +#define CALLER_ADDR5 ((unsigned long)ftrace_return_address(5))
>> +#define CALLER_ADDR6 ((unsigned long)ftrace_return_address(6))
>
> Other than that, it looks good. You can send me the patch and I'll add
> it to my 3.16 queue.
>
> Feel free to reply to this email with a v9. When I pull patches into
> git, it adds the link to the thread for the patch in LKML. To keep this
> entire thread, just reply to it.
>
> Thanks!
>
> -- Steve
>
>>
>>   #ifdef CONFIG_IRQSOFF_TRACER
>>     extern void time_hardirqs_on(unsigned long a0, unsigned long a1);
>