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Re: [PATCH v7 04/17] tracing: add static function tracer support for MIP

Subject: Re: [PATCH v7 04/17] tracing: add static function tracer support for MIPS
From: Wu Zhangjin <>
Date: Thu, 12 Nov 2009 19:06:05 +0800
Cc:,,, Ralf Baechle <>,, Frederic Weisbecker <>, Ingo Molnar <>, Nicholas Mc Guire <>, David Daney <>, Richard Sandiford <>, Patrik Kluba <>, Thomas Gleixner <>, Michal Simek <>
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Organization: DSLab, Lanzhou University, China
Original-recipient: rfc822;
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Hi, All

On Mon, 2009-11-09 at 23:31 +0800, Wu Zhangjin wrote:
> And to support module tracing, we need to enable -mlong-calls for the
> long call from modules space to kernel space. -mlong-calls load the
> address of _mcount to a register and then jump to it, so, the address is
> allowed to be 32bit long, but without -mlong-calls, for the instruction
> "jal _mcount" only left 26bit for the address of _mcount, which is not
> enough for jumping from the module space to kernel space.
> diff --git a/arch/mips/Makefile b/arch/mips/Makefile
> +else
> +cflags-y := -mlong-calls
> +endif

Just made dynamic ftracer work without the above patch.

Will send it out as v8 later.

any more feedbacks to this v7 patchset?

Thanks & Regards,
        Wu Zhangjin

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