Re: [PATCH v2 1/2] MIPS: ftrace: Tweak safe_load()/safe_store() macros

[Ralf Baechle <ralf@linux-mips.org>]

On Sat, Feb 22, 2014 at 03:46:48PM +0800, Viller Hsiao wrote:

> Due to name collision in ftrace safe_load and safe_store macros,
> these macros cannot take expressions as operands.
> 
> For example, compiler will complain for a macro call like the following:
>   safe_store_code(new_code2, ip + 4, faulted);
> 
>   arch/mips/include/asm/ftrace.h:61:6: note: in definition of macro 'safe_store'
>      : [dst] "r" (dst), [src] "r" (src)\
>         ^
>   arch/mips/kernel/ftrace.c:118:2: note: in expansion of macro 'safe_store_code'
>     safe_store_code(new_code2, ip + 4, faulted);
>     ^
>   arch/mips/kernel/ftrace.c:118:32: error: undefined named operand 'ip + 4'
>     safe_store_code(new_code2, ip + 4, faulted);
>                                   ^
>   arch/mips/include/asm/ftrace.h:61:6: note: in definition of macro 'safe_store'
>      : [dst] "r" (dst), [src] "r" (src)\
>         ^
>   arch/mips/kernel/ftrace.c:118:2: note: in expansion of macro 'safe_store_code'
>     safe_store_code(new_code2, ip + 4, faulted);
>     ^
> 
> This patch tweaks variable naming in those macros to allow flexible
> operands.

Interesting catch - and while I think your patch indeed is an improvment
nobody seems to have observed this in a kernel tree, so I'm going to treat
this as a non-urgent improvment and queue it for 3.15.

If this can be triggered in any -stable or v3.14-rc7 tree, please let me
know.

Thanks,

  Ralf