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Differential D7473 Diff 19206 lib/libc/x86/sys/__vdso_gettc.c

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lib/libc/x86/sys/__vdso_gettc.c

  • This file was moved from lib/libc/i386/sys/__vdso_gettc.c.
/*- /*-
* Copyright (c) 2012 Konstantin Belousov <kib@FreeBSD.org> * Copyright (c) 2012 Konstantin Belousov <kib@FreeBSD.org>
* Copyright (c) 2016 The FreeBSD Foundation
* All rights reserved.
* *
* Portions of this software were developed by Konstantin Belousov
* under sponsorship from the FreeBSD Foundation.
*
* Redistribution and use in source and binary forms, with or without * Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions * modification, are permitted provided that the following conditions
* are met: * are met:
* 1. Redistributions of source code must retain the above copyright * 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer. * notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright * 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the * notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution. * documentation and/or other materials provided with the distribution.
Show All 9 Lines
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE. * SUCH DAMAGE.
*/ */
#include <sys/cdefs.h> #include <sys/cdefs.h>
__FBSDID("$FreeBSD$"); __FBSDID("$FreeBSD$");
#include <sys/types.h> #include <sys/param.h>
#include "namespace.h"
#include <sys/elf.h> #include <sys/elf.h>
#include <sys/fcntl.h>
#include <sys/mman.h>
#include <sys/time.h> #include <sys/time.h>
#include <sys/vdso.h> #include <sys/vdso.h>
#include <errno.h>
#include <string.h>
#include <unistd.h>
#include "un-namespace.h"
#include <machine/cpufunc.h> #include <machine/cpufunc.h>
#include <machine/specialreg.h> #include <machine/specialreg.h>
#include <dev/acpica/acpi_hpet.h>
#include "libc_private.h" #include "libc_private.h"
static int lfence_works = -1; static void
lfence_mb(void)
static int
get_lfence_usage(void)
{ {
#if defined(__i386__)
static int lfence_works = -1;
u_int cpuid_supported, p[4]; u_int cpuid_supported, p[4];
if (lfence_works == -1) { if (lfence_works == -1) {
__asm __volatile( __asm __volatile(
" pushfl\n" " pushfl\n"
" popl %%eax\n" " popl %%eax\n"
" movl %%eax,%%ecx\n" " movl %%eax,%%ecx\n"
" xorl $0x200000,%%eax\n" " xorl $0x200000,%%eax\n"
" pushl %%eax\n" " pushl %%eax\n"
" popfl\n" " popfl\n"
" pushfl\n" " pushfl\n"
" popl %%eax\n" " popl %%eax\n"
" xorl %%eax,%%ecx\n" " xorl %%eax,%%ecx\n"
" je 1f\n" " je 1f\n"
" movl $1,%0\n" " movl $1,%0\n"
" jmp 2f\n" " jmp 2f\n"
"1: movl $0,%0\n" "1: movl $0,%0\n"
"2:\n" "2:\n"
: "=r" (cpuid_supported) : : "eax", "ecx"); : "=r" (cpuid_supported) : : "eax", "ecx", "cc");
if (cpuid_supported) { if (cpuid_supported) {
__asm __volatile( __asm __volatile(
" pushl %%ebx\n" " pushl %%ebx\n"
" cpuid\n" " cpuid\n"
" movl %%ebx,%1\n" " movl %%ebx,%1\n"
" popl %%ebx\n" " popl %%ebx\n"
: "=a" (p[0]), "=r" (p[1]), "=c" (p[2]), "=d" (p[3]) : "=a" (p[0]), "=r" (p[1]), "=c" (p[2]), "=d" (p[3])
: "0" (0x1)); : "0" (0x1));
lfence_works = (p[3] & CPUID_SSE2) != 0; lfence_works = (p[3] & CPUID_SSE2) != 0;
} else } else
lfence_works = 0; lfence_works = 0;
} }
return (lfence_works); if (lfence_works == 1)
lfence();
#elif defined(__amd64__)
lfence();
#else
#error "arch"
#endif
} }
static u_int static u_int
__vdso_gettc_low(const struct vdso_timehands *th) __vdso_gettc_rdtsc_low(const struct vdso_timehands *th)
{ {
u_int rv; u_int rv;
if (get_lfence_usage() == 1) lfence_mb();
lfence();
__asm __volatile("rdtsc; shrd %%cl, %%edx, %0" __asm __volatile("rdtsc; shrd %%cl, %%edx, %0"
: "=a" (rv) : "c" (th->th_x86_shift) : "edx"); : "=a" (rv) : "c" (th->th_x86_shift) : "edx");
return (rv); return (rv);
} }
static u_int static u_int
__vdso_rdtsc32(void) __vdso_rdtsc32(void)
{ {
u_int rv;
if (get_lfence_usage() == 1) lfence_mb();
lfence(); return (rdtsc32());
rv = rdtsc32();
return (rv);
} }
static char *hpet_dev_map = NULL;
static uint32_t hpet_idx = 0xffffffff;
static void
__vdso_init_hpet(uint32_t u)
{
static const char devprefix[] = "/dev/hpet";
char devname[64], *c, *c1, t;
int fd;
c1 = c = stpcpy(devname, devprefix);
u = hpet_idx;
do {
*c++ = u % 10 + '0';
u /= 10;
} while (u != 0);
*c = '\0';
for (c--; c1 != c; c1++, c--) {
t = *c1;
*c1 = *c;
*c = t;
}
fd = _open(devname, O_RDONLY);
if (fd == -1) {
hpet_dev_map = MAP_FAILED;
return;
}
if (hpet_dev_map != NULL && hpet_dev_map != MAP_FAILED)
munmap(hpet_dev_map, PAGE_SIZE);
hpet_dev_map = mmap(NULL, PAGE_SIZE, PROT_READ, MAP_SHARED, fd, 0);
_close(fd);
}
#pragma weak __vdso_gettc #pragma weak __vdso_gettc
u_int int
__vdso_gettc(const struct vdso_timehands *th) __vdso_gettc(const struct vdso_timehands *th, u_int *tc)
{ {
uint32_t tmp;
return (th->th_x86_shift > 0 ? __vdso_gettc_low(th) : switch (th->th_algo) {
__vdso_rdtsc32()); case VDSO_TH_ALGO_X86_TSC:
*tc = th->th_x86_shift > 0 ? __vdso_gettc_rdtsc_low(th) :
__vdso_rdtsc32();
return (0);
case VDSO_TH_ALGO_X86_HPET:
tmp = th->th_x86_hpet_idx;
if (hpet_dev_map == NULL || tmp != hpet_idx) {
hpet_idx = tmp;
__vdso_init_hpet(hpet_idx);
}
if (hpet_dev_map == MAP_FAILED)
return (ENOSYS);
*tc = *(volatile uint32_t *)(hpet_dev_map + HPET_MAIN_COUNTER);
return (0);
default:
return (ENOSYS);
}
} }
#pragma weak __vdso_gettimekeep #pragma weak __vdso_gettimekeep
int int
__vdso_gettimekeep(struct vdso_timekeep **tk) __vdso_gettimekeep(struct vdso_timekeep **tk)
{ {
return (_elf_aux_info(AT_TIMEKEEP, tk, sizeof(*tk))); return (_elf_aux_info(AT_TIMEKEEP, tk, sizeof(*tk)));
} }