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Date: Wed, 4 Feb 2009 17:50:24 +0100
Message-ID: <c62985530902040850u5f9e7ca2w6ffbf553ec15eec5@mail.gmail.com>
Subject: Re: [PATCH 3/3] tracing: Tracers that use CALLER_ADDR macros should 
	select FRAME_POINTER
From: =?ISO-8859-1?Q?Fr=E9d=E9ric_Weisbecker?= <fweisbec@gmail.com>
To: avorontsov@ru.mvista.com, Steven Rostedt <srostedt@redhat.com>
Cc: Ingo Molnar <mingo@elte.hu>, Paul Mackerras <paulus@samba.org>,
       Benjamin Herrenschmidt <benh@kernel.crashing.org>,
       linuxppc-dev@ozlabs.org, linux-kernel@vger.kernel.org,
       linux-rt-users@vger.kernel.org
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2009/2/4 Steven Rostedt <srostedt@redhat.com>:
>
> >From ftrace.h:
>
> #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
>
> Yep!
>

Ok.

2009/2/4 Anton Vorontsov <avorontsov@ru.mvista.com>:
> It depends on the architecture. On PowerPC we always have frame pointers,
> thus __builtin_return_address(1..) will always work. On x86 it won't work
> that way.
>
> Thanks,
>
> --
> Anton Vorontsov

Thanks for your answers!