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Re: [patch] Prevent dead code/data removal with gcc 3.4

To: Thiemo Seufer <>
Subject: Re: [patch] Prevent dead code/data removal with gcc 3.4
From: Ralf Baechle <>
Date: Sat, 14 Feb 2004 02:45:20 +0100
Cc: David Daney <>, "Maciej W. Rozycki" <>,
In-reply-to: <>
Original-recipient: rfc822;
References: <> <> <> <> <> <> <>
User-agent: Mutt/1.4.1i
On Sat, Feb 14, 2004 at 02:28:01AM +0100, Thiemo Seufer wrote:

> > It's the gcc generated function epilogue which is the problem.  There's
> > no reliable way to work around that ...
> ITYM prologue. It has to follow the ABI specification, so $fp is the only
> possibly problematic one, and that's excluded by -fomit-frame-pointers.

Daniel Jacobowitz reported the problem which indeed was about $30.  Since
the kernel uses -fomit-frame-pointer by default (and -O1 enables it
by default on MIPS anyway) I would assume his kernel was built using that
option.  Maybe he can elaborate ...

Anyway, gcc could load next weeks lucky lottery numbers into the
s-registers after saving them.  That'd break save_static but not the
ABI which only promises to restore the old values in s-registers on


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