From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Krzysztof Helt" Date: Wed, 26 Jan 2005 08:57:25 +0000 Subject: Re: FPU context switching fix for SMP Message-Id: <41f75b75a4c13@wp.pl> List-Id: References: <41f753cabb795@wp.pl> In-Reply-To: <41f753cabb795@wp.pl> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable To: sparclinux@vger.kernel.org Dnia 26-01-2005 o godz. 9:26 William Lee Irwin III napisa=B3(a): > 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. >=20 > Are you sure a bugfix merits a copyright attribution? It's atypical > elsewhere... >=20 >=20 So please remove it. I am quite new, so just don't know how to measure it... Krzysztof ---------------------------------------------------- W Stepford kobiety s=B1 idealne, a m=EA=BFczy=BCni szcz=EA=B6liwi, dlaczego? Zobacz, Nicole Kidman w filmie "=AFony ze Stepford"=20 Musisz je mie=E6 na DVD i Wideo! http://klik.wp.pl/?adr=3Dhttp%3A%2F%2Ffilm.wp.pl%2Fp%2Ffilm.html%3Fid%3D244= 49&sid05