Re: [PATCH 06/10] ARM: ftrace: add Thumb-2 support

From: Catalin Marinas
Date: Fri Apr 23 2010 - 11:39:13 EST


On Wed, 2010-03-31 at 19:25 +0100, Rabin Vincent wrote:
> From bf828a0c069b1bb3f6bf4e68f1dceecab396c286 Mon Sep 17 00:00:00 2001
> From: Rabin Vincent <rabin@xxxxxx>
> Date: Sun, 14 Feb 2010 01:18:34 +0530
> Subject: [PATCH 06/10] ARM: ftrace: add Thumb-2 support
>
> Fix the mcount routines to build and run on a kernel built with the
> Thumb-2 instruction set by correcting the following errors using the
> fixes suggested by Catalin Marinas:
>
> - Problem: The following assembler errors appear at the "adr r0,
> ftrace_stub" instruction:
>
> entry-common.S: Assembler messages:
> entry-common.S:179: Error: invalid immediate for address calculation (value = 0x00000004)
>
> Fix: The errors don't occur with a non-global symbol, so use one.
>
> - Problem: The "mov lr, pc" does not set the lsb when storing the pc in
> lr. The called function returns with "bx lr", and the mode changes
> to ARM.
>
> Fix: Add a label on the return address and use "adr lr, BSYM(label)".
>
> We don't modify the old mcount because it won't be built when using
> Thumb-2.
>
> Cc: Catalin Marinas <catalin.marinas@xxxxxxx>
> Signed-off-by: Rabin Vincent <rabin@xxxxxx>

Acked-by: Catalin Marinas <catalin.marinas@xxxxxxx>

--
Catalin

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