Messages in this thread | | | Date | Tue, 3 Oct 2006 09:49:26 -0700 | From | Randy Dunlap <> | Subject | Re: [PATCH/RFC] Math-emu kills the kernel on Athlon64 X2 |
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On Tue, 3 Oct 2006 09:37:45 -0700 (PDT) Linus Torvalds wrote:
> > > On Tue, 3 Oct 2006, Randy Dunlap wrote: > > > > Yes, that works. > > Ok. I'll commit that simple thing, and add a comment on why we're > apparently doing the same thing twice (you do need _both_ of those things: > the "disable_x86_fxsr" will make sure all other CPU's also get cleared, > while the "clear_bit()" will clear it immediately on the boot CPU) > > I'll leave the no387/nofxsr linking alone for now. The main reason to use > no387 would seem to be just testing that emulation works at all, and I > guess we can just tell people to use the "no387 nofxsr" combination. > > So Randy, with this you can boot all the way into user space, and some FP > apps still work too?
My few trivial float and double apps work. Is there any particular test/workload that you want me to run?
> (Of course, user-space may be buggy and use SSE etc without testing for > whether the CPU actually supports it - if the install process has > installed some special SSE-version of a library depending on what the CPU > claimed at that point, or if somebody uses "cpuid" directly rather than > asking the kernel. So there's no way we're going to _guarantee_ that this > works in user space, but at least a well-behaved user-space that works on > a i486 should hopefully be ok).
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