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    Subject[PATCH] make CALLER_ADDRx overwriteable
    Date
    The current definition of CALLER_ADDRx isn't suitable for all platforms.
    E.g. for ARM __builtin_return_address(N) doesn't work for N > 0 and
    AFAIK for powerpc there are no frame pointers needed to have a working
    __builtin_return_address. This patch allows defining the CALLER_ADDRx
    macros in <asm/ftrace.h> and let these take precedence.

    Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
    ---
    Hello,

    [I resent because vger blocked my mail saying: "Wrong MIME labeling on
    8-bit character texts." Steven didn't get it either. I don't know
    what's wrong, so I put the patch back into git and format-patch'd it. I
    hope this one makes it through. Sorry if you got it twice.]

    I think I don't break any architecture with this patch:

    $ for arch in $(ls arch/); do if test ! -d arch/$arch; then continue; fi; test -f arch/$arch/include/asm/ftrace.h || test -f include/asm-$arch/ftrace.h || { echo -n "$arch: "; git grep FTRACE arch/$arch | wc -l; } done
    alpha: 0
    avr32: 0
    blackfin: 0
    cris: 0
    frv: 0
    h8300: 0
    m32r: 0
    m68k: 0
    m68knommu: 0
    mips: 0
    mn10300: 0
    parisc: 0
    um: 0
    xtensa: 0

    So all archs that don't have <asm/ftrace.h> seem not to use FTRACE.

    Best regards
    Uwe

    include/linux/ftrace.h | 41 +++++++++++++++++++++--------------------
    1 files changed, 21 insertions(+), 20 deletions(-)

    diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h
    index 847bb3c..9d8d362 100644
    --- a/include/linux/ftrace.h
    +++ b/include/linux/ftrace.h
    @@ -11,6 +11,8 @@
    #include <linux/bitops.h>
    #include <linux/sched.h>

    +#include <asm/ftrace.h>
    +
    #ifdef CONFIG_FUNCTION_TRACER

    extern int ftrace_enabled;
    @@ -103,8 +105,6 @@ struct ftrace_func_command {
    };

    #ifdef CONFIG_DYNAMIC_FTRACE
    -/* asm/ftrace.h must be defined for archs supporting dynamic ftrace */
    -#include <asm/ftrace.h>

    int ftrace_arch_code_modify_prepare(void);
    int ftrace_arch_code_modify_post_process(void);
    @@ -282,24 +282,25 @@ static inline void __ftrace_enabled_restore(int enabled)
    #endif
    }

    -#ifdef CONFIG_FRAME_POINTER
    -/* TODO: need to fix this for ARM */
    -# 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))
    -#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
    -#endif
    +#ifndef CALLER_ADDR0
    +# 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))
    +# 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
    +# endif
    +#endif /* ifndef CALLER_ADDR0 */

    #ifdef CONFIG_IRQSOFF_TRACER
    extern void time_hardirqs_on(unsigned long a0, unsigned long a1);
    --
    tg: (db50eec..) t/ftrace/make_CALLER_ADDRx_overwriteable (depends on: tip/master)
    --
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