[systemd-devel] rdrand generated with march=winchip-c6 in systemd-241

[Olaf van der Spek]

On Sun, May 19, 2019 at 2:31 PM tedheadster <tedheadster at gmail.com> wrote:
>
> On Sun, May 19, 2019 at 7:31 AM Olaf van der Spek <ml at vdspek.org> wrote:
> >
> > What's eax after cpuid function 0?
>
> After calling cpuid function 0x0, %eax returns the expected 0x1.
>
> Here is the output of 'cpuid -r'.
>
> # cpuid -r
> CPU 0:
>    0x00000000 0x00: eax=0x00000001 ebx=0x746e6543 ecx=0x736c7561 edx=0x48727561
>    0x00000001 0x00: eax=0x00000585 ebx=0x746e6543 ecx=0x00000000 edx=0x008001b5

ecx does contain 0 doesn't it? Or is this the wrong line?

> I think %ecx  should properly contain 0x00000000, but it instead puts
the 'auls' characters from cpuid function 0x00000000 (vendor string
'CentaurHauls') in %ecx:

>    0x80000000 0x00: eax=0x80000005 ebx=0x00000000 ecx=0x00000000 edx=0x00000050
>    0x80000001 0x00: eax=0x00000585 ebx=0x00000000 ecx=0x00000000 edx=0x808001b5
>    0x80000002 0x00: eax=0x20544449 ebx=0x436e6957 ecx=0x20706968 edx=0x44332d32
>    0x80000003 0x00: eax=0x00000000 ebx=0x00000000 ecx=0x00000000 edx=0x00000000
>    0x80000004 0x00: eax=0x00000000 ebx=0x00000000 ecx=0x00000000 edx=0x00000000
>    0x80000005 0x00: eax=0x80000005 ebx=0x08800880 ecx=0x20040120 edx=0x20020120
>    0x80860000 0x00: eax=0x80860000 ebx=0x08800880 ecx=0x00000000 edx=0x00000050
>    0xc0000000 0x00: eax=0xc0000005 ebx=0x08800880 ecx=0x00000000 edx=0x00000050
>    0xc0000001 0x00: eax=0x00000585 ebx=0x08800880 ecx=0x00000000 edx=0x808001b5
>    0xc0000002 0x00: eax=0x20544449 ebx=0x436e6957 ecx=0x20706968 edx=0x44332d32
>    0xc0000003 0x00: eax=0x00000000 ebx=0x00000000 ecx=0x00000000 edx=0x00000000
>    0xc0000004 0x00: eax=0x00000000 ebx=0x00000000 ecx=0x00000000 edx=0x00000000
>    0xc0000005 0x00: eax=0xc0000005 ebx=0x08800880 ecx=0x20040120 edx=0x20020120


-- 
Olaf