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Message-Id: <1244204320.13761.4302.camel@twins>
Date: Fri, 05 Jun 2009 14:18:40 +0200
From: Peter Zijlstra <peterz@...radead.org>
To: Paul Mackerras <paulus@...ba.org>
Cc: Ingo Molnar <mingo@...e.hu>, Thomas Gleixner <tglx@...utronix.de>,
"H. Peter Anvin" <hpa@...or.com>, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] x86: Code atomic[64]_read and atomic[64]_set in C not
CPP
On Fri, 2009-06-05 at 20:43 +1000, Paul Mackerras wrote:
> Occasionally we get bugs where atomic_read or atomic_set are used on
> atomic64_t variables or vice versa. These bugs don't generate
> warnings on x86 because atomic_read and atomic_set are coded as macros
> rather than C functions, so we don't get any type-checking on their
> arguments; similarly for atomic64_read and atomic64_set in 64-bit
> kernels.
>
> This converts them to C functions so that the arguments are
> type-checked and bugs like this will get caught more easily.
> It also converts atomic_cmpxchg and atomic_xchg, and atomic64_cmpxchg
> and atomic64_xchg on 64-bit, so we get type-checking on their
> arguments too.
>
> Compiling a typical 64-bit x86 config, this generates no new warnings,
> and the vmlinux text is 86 bytes smaller.
>
> Signed-off-by: Paul Mackerras <paulus@...ba.org>
Nice!
Acked-by: Peter Zijlstra <a.p.zijlstra@...llo.nl>
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