On Tue, May 21, 2019 at 11:20 AM Uros Bizjak wrote:
>
> 2019-05-21 Uroš Bizjak
>
> * config/i386/cpuid.h (__cpuid): For 32bit targets, zero
> %ebx and %ecx bafore calling cpuid with leaf 1 or
> non-constant leaf argument.
>
> Bootstrapped and regression tested on x86_64-linux-gnu {,
On Tue, 21 May 2019, Uros Bizjak wrote:
> --cut here--
> #include "cpuid.h"
>
> int main ()
> {
> unsigned int eax, ebx, ecx, edx;
>
> if (!__get_cpuid (1, &eax, &ebx, &ecx, &edx))
> __builtin_abort ();
>
> printf ("%#x, %#x, %#x, %#x\n", eax, ebx, ecx, edx);
> return 0;
> }
> --cut
On Tue, May 21, 2019 at 9:46 AM Uros Bizjak wrote:
>
> On Tue, May 21, 2019 at 12:20 AM tedheadster wrote:
> >
> > On Mon, May 20, 2019 at 2:57 PM Uros Bizjak wrote:
> > >
> > > On Mon, May 20, 2019 at 6:12 PM tedheadster wrote:
> > > > Did you instead mean "zeroing %EBX and %ECX regs should be
On Tue, May 21, 2019 at 12:20 AM tedheadster wrote:
>
> On Mon, May 20, 2019 at 2:57 PM Uros Bizjak wrote:
> >
> > On Mon, May 20, 2019 at 6:12 PM tedheadster wrote:
> > > Did you instead mean "zeroing %EBX and %ECX regs should be enough"?
> >
> > Ah, yes. This is what I meant to say. The patch
On Mon, May 20, 2019 at 2:57 PM Uros Bizjak wrote:
>
> On Mon, May 20, 2019 at 6:12 PM tedheadster wrote:
> > Did you instead mean "zeroing %EBX and %ECX regs should be enough"?
>
> Ah, yes. This is what I meant to say. The patch clears %ebx and %ecx.
>
Uros,
your patch worked on real 32-bit h
On Mon, May 20, 2019 at 6:12 PM tedheadster wrote:
>
> On Mon, May 20, 2019 at 11:52 AM Uros Bizjak wrote:
>
> > How about the attached patch that enables zeroing only for 32bit
> > processors, and only for cpuid leaf 1? Usually, __get_cpuid is used
> > with a constant leaf argument, so we benefi
On Mon, May 20, 2019 at 11:52 AM Uros Bizjak wrote:
> How about the attached patch that enables zeroing only for 32bit
> processors, and only for cpuid leaf 1? Usually, __get_cpuid is used
> with a constant leaf argument, so we benefit from constant propagation
> into inline function. Also, accor
On Mon, May 20, 2019 at 4:24 PM tedheadster wrote:
>
> Uros,
>
> On Mon, May 20, 2019 at 3:29 AM Uros Bizjak wrote:
> > The CPUID documentation from Intel Architectures Developer's manual is
> > crystal clear on the implementation:
> >
> > --quote--
> > CPUID—CPU Identification
> >
> > Returns pr
On Sun, May 19, 2019 at 12:10 PM tedheadster wrote:
>
> I have confirmed that the IDT Winchip 2 does not expressly set %ecx
> after a call to cpuid() with %eax = 1, and this causes incorrect
> reporting of cpu capabilities. The %ecx register should return 0x0
> (and likely %ebx should too) on this
Uros,
On Mon, May 20, 2019 at 3:29 AM Uros Bizjak wrote:
> The CPUID documentation from Intel Architectures Developer's manual is
> crystal clear on the implementation:
>
> --quote--
> CPUID—CPU Identification
>
> Returns processor identification and feature
> information to the EAX, EBX, ECX, an
Hello!
> I have confirmed that the IDT Winchip 2 does not expressly set %ecx
> after a call to cpuid() with %eax = 1, and this causes incorrect
> reporting of cpu capabilities. The %ecx register should return 0x0
> (and likely %ebx should too) on this hardware. This patch proposes a
> fix.
>
> The
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