[systemd-devel] rdrand generated with march=winchip-c6 in systemd-241
Olaf van der Spek
ml at vdspek.org
Sun May 19 11:31:34 UTC 2019
On Sat, May 11, 2019 at 7:19 PM tedheadster <tedheadster at gmail.com> wrote:
> On Sat, May 11, 2019 at 12:30 PM Florian Weimer <fw at deneb.enyo.de> wrote:
> > Can you capture register contents at the point of the crash?
> > Does this reproduce in a chroot? Maybe you can trace the whole thing
> > with a debugger. Does the crash reproduce if you single-step through
> > the whole function?
> I figured out the problem, I just haven't written code to fix it.
> The documentation I can find is silent about what is returned in %ecx
> and %ebx when calling cpuid function 0x00000001 on IDT Winchip-C6 and
> I think %ecx should properly contain 0x00000000, but it instead puts
> the 'auls' characters from cpuid function 0x00000000 (vendor string
> 'CentaurHauls') in %ecx:
> %ebx = 0x746e6543 = "Cent"
> %edx = 0x48727561 = "aurH"
> %ecx = 0x736c7561 = "auls"
What's eax after cpuid function 0?
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