From: Tony Breeds <tony@bakeyournoodle.com>
Date: Tue, 2 Sep 2008 06:50:38 +0000 (+1000)
Subject: powerpc: Work around gcc's -fno-omit-frame-pointer bug
X-Git-Tag: v2.6.27-rc6~46^2~2
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=7563dc64585324f443f5ac107eb6d89ee813a2d2;p=pandora-kernel.git

powerpc: Work around gcc's -fno-omit-frame-pointer bug

This bug is causing random crashes
(http://bugzilla.kernel.org/show_bug.cgi?id=11414).

-fno-omit-frame-pointer is only needed on powerpc when -pg is also
supplied, and there is a gcc bug that causes incorrect code generation
on 32-bit powerpc when -fno-omit-frame-pointer is used---it uses stack
locations below the stack pointer, which is not allowed by the ABI
because those locations can and sometimes do get corrupted by an
interrupt.

This ensures that CONFIG_FRAME_POINTER is only selected by ftrace.
When CONFIG_FTRACE is enabled we also pass -mno-sched-epilog to work
around the gcc codegen bug.

Patch based on work by:
	Andreas Schwab <schwab@suse.de>
	Segher Boessenkool <segher@kernel.crashing.org>

Signed-off-by: Tony Breeds <tony@bakeyournoodle.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>
---

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