diff options
Diffstat (limited to 'lib/libc/x86/sys')
| -rw-r--r-- | lib/libc/x86/sys/Makefile.inc | 6 | ||||
| -rw-r--r-- | lib/libc/x86/sys/__vdso_gettc.c | 179 |
2 files changed, 185 insertions, 0 deletions
diff --git a/lib/libc/x86/sys/Makefile.inc b/lib/libc/x86/sys/Makefile.inc new file mode 100644 index 0000000..c00a217 --- /dev/null +++ b/lib/libc/x86/sys/Makefile.inc @@ -0,0 +1,6 @@ +# $FreeBSD$ + +.PATH: ${LIBC_SRCTOP}/x86/sys + +SRCS+= \ + __vdso_gettc.c diff --git a/lib/libc/x86/sys/__vdso_gettc.c b/lib/libc/x86/sys/__vdso_gettc.c new file mode 100644 index 0000000..743b3ad --- /dev/null +++ b/lib/libc/x86/sys/__vdso_gettc.c @@ -0,0 +1,179 @@ +/*- + * Copyright (c) 2012 Konstantin Belousov <kib@FreeBSD.org> + * Copyright (c) 2016 The FreeBSD Foundation + * All rights reserved. + * + * Portions of this software were developed by Konstantin Belousov + * under sponsorship from the FreeBSD Foundation. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * + * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND + * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE + * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE + * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL + * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS + * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) + * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT + * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY + * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF + * SUCH DAMAGE. + */ + +#include <sys/cdefs.h> +__FBSDID("$FreeBSD$"); + +#include <sys/param.h> +#include "namespace.h" +#include <sys/elf.h> +#include <sys/fcntl.h> +#include <sys/mman.h> +#include <sys/time.h> +#include <sys/vdso.h> +#include <errno.h> +#include <string.h> +#include <unistd.h> +#include "un-namespace.h" +#include <machine/cpufunc.h> +#include <machine/specialreg.h> +#include <dev/acpica/acpi_hpet.h> +#include "libc_private.h" + +static void +lfence_mb(void) +{ +#if defined(__i386__) + static int lfence_works = -1; + u_int cpuid_supported, p[4]; + + if (lfence_works == -1) { + __asm __volatile( + " pushfl\n" + " popl %%eax\n" + " movl %%eax,%%ecx\n" + " xorl $0x200000,%%eax\n" + " pushl %%eax\n" + " popfl\n" + " pushfl\n" + " popl %%eax\n" + " xorl %%eax,%%ecx\n" + " je 1f\n" + " movl $1,%0\n" + " jmp 2f\n" + "1: movl $0,%0\n" + "2:\n" + : "=r" (cpuid_supported) : : "eax", "ecx", "cc"); + if (cpuid_supported) { + __asm __volatile( + " pushl %%ebx\n" + " cpuid\n" + " movl %%ebx,%1\n" + " popl %%ebx\n" + : "=a" (p[0]), "=r" (p[1]), "=c" (p[2]), "=d" (p[3]) + : "0" (0x1)); + lfence_works = (p[3] & CPUID_SSE2) != 0; + } else + lfence_works = 0; + } + if (lfence_works == 1) + lfence(); +#elif defined(__amd64__) + lfence(); +#else +#error "arch" +#endif +} + +static u_int +__vdso_gettc_rdtsc_low(const struct vdso_timehands *th) +{ + u_int rv; + + lfence_mb(); + __asm __volatile("rdtsc; shrd %%cl, %%edx, %0" + : "=a" (rv) : "c" (th->th_x86_shift) : "edx"); + return (rv); +} + +static u_int +__vdso_rdtsc32(void) +{ + + lfence_mb(); + return (rdtsc32()); +} + +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 +int +__vdso_gettc(const struct vdso_timehands *th, u_int *tc) +{ + uint32_t tmp; + + switch (th->th_algo) { + 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 +int +__vdso_gettimekeep(struct vdso_timekeep **tk) +{ + + return (_elf_aux_info(AT_TIMEKEEP, tk, sizeof(*tk))); +} |
