Date: Mon, 22 May 2006 08:51:39 +0800 From: David Xu <davidxu@freebsd.org> To: freebsd-current@freebsd.org Cc: Rostislav Krasny <rosti.bsd@gmail.com>, Igor Sysoev <is@rambler-co.ru>, Colin Percival <cperciva@freebsd.org> Subject: Re: [PATCH] FreeBSD-SA-06:14.fpu Message-ID: <200605220851.40212.davidxu@freebsd.org> In-Reply-To: <200605212351.k4LNpmhJ095330@apollo.backplane.com> References: <20060430142408.fcd60069.rosti.bsd@gmail.com> <200605211606.43381.davidxu@freebsd.org> <200605212351.k4LNpmhJ095330@apollo.backplane.com>
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On Monday 22 May 2006 07:51, Matthew Dillon wrote: > :> By the way, following command could be used to check how kernel has > :> been compiled, regarding the CPU_FXSAVE_LEAK option: > :> > :> objdump -x /boot/kernel/kernel | grep fpu_clean_state > : > :The patch looks fine to me, but can it be CPU_FXSAVE_NOLEAK ? > :so only people know the problem will turn it on. > : > :David Xu > > I don't think it really needs to be optioned. Since the FPU state > is demand-loaded from a trap/exception anyway, a huge amount of code > is run in the same path that fpu_clean_state is called from. > fpu_clean_state itself only eats a few nanoseconds (like maybe ~1/10 > of the time that fninit takes). > > -Matt > > I personally hate to see such nasty code if my CPU does not have such a nasty bug, I don't know if the existing code really has impact in real world. David Xu
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