180 lines
4.5 KiB
C
180 lines
4.5 KiB
C
/*-
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* Copyright (c) 2012 Konstantin Belousov <kib@FreeBSD.org>
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* Copyright (c) 2016 The FreeBSD Foundation
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* All rights reserved.
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*
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* Portions of this software were developed by Konstantin Belousov
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* under sponsorship from the FreeBSD Foundation.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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#include <sys/param.h>
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#include "namespace.h"
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#include <sys/elf.h>
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#include <sys/fcntl.h>
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#include <sys/mman.h>
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#include <sys/time.h>
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#include <sys/vdso.h>
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#include <errno.h>
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#include <string.h>
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#include <unistd.h>
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#include "un-namespace.h"
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#include <machine/cpufunc.h>
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#include <machine/specialreg.h>
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#include <dev/acpica/acpi_hpet.h>
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#include "libc_private.h"
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static void
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lfence_mb(void)
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{
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#if defined(__i386__)
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static int lfence_works = -1;
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u_int cpuid_supported, p[4];
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if (lfence_works == -1) {
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__asm __volatile(
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" pushfl\n"
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" popl %%eax\n"
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" movl %%eax,%%ecx\n"
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" xorl $0x200000,%%eax\n"
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" pushl %%eax\n"
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" popfl\n"
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" pushfl\n"
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" popl %%eax\n"
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" xorl %%eax,%%ecx\n"
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" je 1f\n"
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" movl $1,%0\n"
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" jmp 2f\n"
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"1: movl $0,%0\n"
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"2:\n"
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: "=r" (cpuid_supported) : : "eax", "ecx", "cc");
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if (cpuid_supported) {
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__asm __volatile(
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" pushl %%ebx\n"
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" cpuid\n"
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" movl %%ebx,%1\n"
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" popl %%ebx\n"
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: "=a" (p[0]), "=r" (p[1]), "=c" (p[2]), "=d" (p[3])
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: "0" (0x1));
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lfence_works = (p[3] & CPUID_SSE2) != 0;
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} else
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lfence_works = 0;
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}
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if (lfence_works == 1)
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lfence();
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#elif defined(__amd64__)
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lfence();
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#else
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#error "arch"
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#endif
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}
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static u_int
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__vdso_gettc_rdtsc_low(const struct vdso_timehands *th)
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{
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u_int rv;
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lfence_mb();
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__asm __volatile("rdtsc; shrd %%cl, %%edx, %0"
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: "=a" (rv) : "c" (th->th_x86_shift) : "edx");
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return (rv);
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}
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static u_int
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__vdso_rdtsc32(void)
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{
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lfence_mb();
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return (rdtsc32());
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}
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static char *hpet_dev_map = NULL;
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static uint32_t hpet_idx = 0xffffffff;
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static void
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__vdso_init_hpet(uint32_t u)
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{
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static const char devprefix[] = "/dev/hpet";
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char devname[64], *c, *c1, t;
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int fd;
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c1 = c = stpcpy(devname, devprefix);
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u = hpet_idx;
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do {
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*c++ = u % 10 + '0';
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u /= 10;
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} while (u != 0);
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*c = '\0';
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for (c--; c1 != c; c1++, c--) {
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t = *c1;
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*c1 = *c;
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*c = t;
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}
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fd = _open(devname, O_RDONLY);
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if (fd == -1) {
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hpet_dev_map = MAP_FAILED;
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return;
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}
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if (hpet_dev_map != NULL && hpet_dev_map != MAP_FAILED)
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munmap(hpet_dev_map, PAGE_SIZE);
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hpet_dev_map = mmap(NULL, PAGE_SIZE, PROT_READ, MAP_SHARED, fd, 0);
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_close(fd);
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}
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#pragma weak __vdso_gettc
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int
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__vdso_gettc(const struct vdso_timehands *th, u_int *tc)
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{
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uint32_t tmp;
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switch (th->th_algo) {
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case VDSO_TH_ALGO_X86_TSC:
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*tc = th->th_x86_shift > 0 ? __vdso_gettc_rdtsc_low(th) :
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__vdso_rdtsc32();
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return (0);
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case VDSO_TH_ALGO_X86_HPET:
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tmp = th->th_x86_hpet_idx;
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if (hpet_dev_map == NULL || tmp != hpet_idx) {
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hpet_idx = tmp;
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__vdso_init_hpet(hpet_idx);
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}
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if (hpet_dev_map == MAP_FAILED)
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return (ENOSYS);
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*tc = *(volatile uint32_t *)(hpet_dev_map + HPET_MAIN_COUNTER);
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return (0);
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default:
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return (ENOSYS);
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}
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}
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#pragma weak __vdso_gettimekeep
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int
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__vdso_gettimekeep(struct vdso_timekeep **tk)
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{
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return (_elf_aux_info(AT_TIMEKEEP, tk, sizeof(*tk)));
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}
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