Date: Sun, 30 Apr 2006 14:24:08 +0300 From: Rostislav Krasny <rosti.bsd@gmail.com> To: David Xu <davidxu@freebsd.org>, Igor Sysoev <is@rambler-co.ru> Cc: freebsd-current@freebsd.org Subject: Re: FreeBSD-SA-06:14.fpu Message-ID: <20060430142408.fcd60069.rosti.bsd@gmail.com>
next in thread | raw e-mail | index | archive | help
David Xu wrote: > Igor Sysoev wrote: > > > > The last security advisory FreeBSD-SA-06:14.fpu > > ftp://ftp.freebsd.org/pub/FreeBSD/CERT/advisories/FreeBSD-SA-06:14.fpu.asc > > that fixes very doubtful security bug in AMD CPUs, also > > adds unnecessary penalty in FPU context switch for all other > > SSE-enabled CPUs. > > Probably it should only be applied to AMD CPU but not Intel and others, > it is easy to check cpu vendor and put a > if (bug_fxsave) > fpu_clean_state(); > > in file npx.c. Other possible solution is making the fpu_clean_state() optional by something like following: #ifdef BUG_FXSAVE #define fpu_clean_state() __fpu_clean_state() #else #define fpu_clean_state() ; #endif ... and including "options BUG_FXSAVE" to GENERIC.
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?20060430142408.fcd60069.rosti.bsd>