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x86 __vdso_gettc(): use machine/cpufunc.h function for CPUID.

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Based on the discussion with:	jkim
Sponsored by:	The FreeBSD Foundation
MFC after:	1 week
This commit is contained in:
Konstantin Belousov 2019-02-14 13:59:00 +00:00
parent 642bb66b63
commit b5d72efb7a
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=344119
1 changed files with 2 additions and 27 deletions
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29
lib/libc/x86/sys/__vdso_gettc.c
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@ -53,31 +53,6 @@ __FBSDID("$FreeBSD$");
#include <x86/ifunc.h>
#include "libc_private.h"
static void
cpuidp(u_int leaf, u_int p[4])
{
__asm __volatile(
#if defined(__i386__)
" pushl %%ebx\n"
#endif
" cpuid\n"
#if defined(__i386__)
" movl %%ebx,%1\n"
" popl %%ebx"
#endif
: "=a" (p[0]),
#if defined(__i386__)
"=r" (p[1]),
#elif defined(__amd64__)
"=b" (p[1]),
#else
#error "Arch"
#endif
"=c" (p[2]), "=d" (p[3])
: "0" (leaf));
}
static void
rdtsc_mb_lfence(void)
{
@ -100,12 +75,12 @@ rdtsc_mb_none(void)
DEFINE_UIFUNC(static, void, rdtsc_mb, (void), static)
{
u_int p[4];
/* Not a typo, string matches our cpuidp() registers use. */
/* Not a typo, string matches our do_cpuid() registers use. */
static const char intel_id[] = "GenuntelineI";
if ((cpu_feature & CPUID_SSE2) == 0)
return (rdtsc_mb_none);
cpuidp(0, p);
do_cpuid(0, p);
return (memcmp(p + 1, intel_id, sizeof(intel_id) - 1) == 0 ?
rdtsc_mb_lfence : rdtsc_mb_mfence);
}