From: William Lee Irwin III <wli@holomorphy.com>
To: sparclinux@vger.kernel.org
Subject: Re: FPU context switching fix for SMP
Date: Wed, 26 Jan 2005 08:26:10 +0000 [thread overview]
Message-ID: <20050126082610.GK10843@holomorphy.com> (raw)
In-Reply-To: <41f753cabb795@wp.pl>
On Wed, Jan 26, 2005 at 09:24:42AM +0100, Krzysztof Helt wrote:
> Here is a patch for FPU context switching in SMP.
> A copy_thread() function clears PF_USEDFPU flag for a new thread,
> but it does not clear the PSR_EF bit. Thus, a first FPU exception
> called from the child thread is not handled properly. I made the
> patch after PPC and MIPS architectures - both clear a similar bit
> in copy_thread.
> This bug does not exist in the UP kernel, probably because it
> does not rely on PF_USEDFPU flag.
> The patch below should be applied for both 2.4 and 2.6 branches.
> I tested it with a test-fenv program from glibc testsuite. The
> test fails the same test cases in both SMP and UP with the patch
> applied. Without the patch, the test on SMP kernel failes in
> almost two times more testcases.
Are you sure a bugfix merits a copyright attribution? It's atypical
elsewhere...
-- wli
next prev parent reply other threads:[~2005-01-26 8:26 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2005-01-26 8:24 FPU context switching fix for SMP Krzysztof Helt
2005-01-26 8:26 ` William Lee Irwin III [this message]
2005-01-26 8:57 ` Krzysztof Helt
2005-01-26 22:06 ` Baurjan Ismagulov
2005-01-26 23:09 ` David S. Miller
2005-01-29 18:22 ` Baurjan Ismagulov
2005-02-15 17:40 ` David S. Miller
2005-02-15 20:01 ` William Lee Irwin III
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