Messages in this thread | | | Date | Tue, 12 Jan 2021 01:09:23 +0100 | From | Borislav Petkov <> | Subject | Re: [PATCH] x86/lib: don't use MMX before FPU initialization |
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On Mon, Dec 28, 2020 at 05:06:31PM +0100, Krzysztof Mazur wrote: > When enabled, the MMX 3DNow! optimized memcpy() is used very early, > even before FPU is initialized. It worked fine, but commit > 7ad816762f9bf89e940e618ea40c43138b479e10 ("x86/fpu: Reset MXCSR > to default in kernel_fpu_begin()") broke that. After that commit > the kernel crashes just after "Booting the kernel." message.
Have you figured out in the meantime what exactly is causing the breakage?
Does it boot if you comment out
+ if (boot_cpu_has(X86_FEATURE_FPU)) + asm volatile ("fninit");
in kernel_fpu_begin()?
I'm guessing K7 doesn't have X86_FEATURE_XMM so the LDMXCSR won't matter...
Thx.
-- Regards/Gruss, Boris.
https://people.kernel.org/tglx/notes-about-netiquette
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