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SubjectRe: [PATCH v8 1/8] ftrace: make CALLER_ADDRx macros more generic
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);



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