Index: head/lib/libc/x86/sys/__vdso_gettc.c =================================================================== --- head/lib/libc/x86/sys/__vdso_gettc.c (revision 343854) +++ head/lib/libc/x86/sys/__vdso_gettc.c (revision 343855) @@ -1,333 +1,294 @@ /*- * Copyright (c) 2012 Konstantin Belousov - * Copyright (c) 2016, 2017 The FreeBSD Foundation + * Copyright (c) 2016, 2017, 2019 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 __FBSDID("$FreeBSD$"); #include #include "namespace.h" #include #include #include #include #include #include #include #include #include #include "un-namespace.h" #include #include #include #include #ifdef WANT_HYPERV #include #endif +#include #include "libc_private.h" -static enum LMB { - LMB_UNKNOWN, - LMB_NONE, - LMB_MFENCE, - LMB_LFENCE -} lfence_works = LMB_UNKNOWN; - 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 enum LMB -select_lmb(void) +static void +rdtsc_mb_lfence(void) { - u_int p[4]; - static const char intel_id[] = "GenuntelineI"; - cpuidp(0, p); - return (memcmp(p + 1, intel_id, sizeof(intel_id) - 1) == 0 ? - LMB_LFENCE : LMB_MFENCE); + lfence(); } static void -init_fence(void) +rdtsc_mb_mfence(void) { -#if defined(__i386__) - u_int cpuid_supported, p[4]; - lfence_works = LMB_NONE; - __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) { - cpuidp(0x1, p); - if ((p[3] & CPUID_SSE2) != 0) - lfence_works = select_lmb(); - } -#elif defined(__amd64__) - lfence_works = select_lmb(); -#else -#error "Arch" -#endif + mfence(); } static void -rdtsc_mb(void) +rdtsc_mb_none(void) { +} -again: - if (__predict_true(lfence_works == LMB_LFENCE)) { - lfence(); - return; - } else if (lfence_works == LMB_MFENCE) { - mfence(); - return; - } else if (lfence_works == LMB_NONE) { - return; - } - init_fence(); - goto again; +DEFINE_UIFUNC(static, void, rdtsc_mb, (void), static) +{ + u_int p[4]; + static const char intel_id[] = "GenuntelineI"; + + if ((cpu_feature & CPUID_SSE2) == 0) + return (rdtsc_mb_none); + cpuidp(0, p); + return (memcmp(p + 1, intel_id, sizeof(intel_id) - 1) == 0 ? + rdtsc_mb_lfence : rdtsc_mb_mfence); } static u_int __vdso_gettc_rdtsc_low(const struct vdso_timehands *th) { u_int rv; rdtsc_mb(); __asm __volatile("rdtsc; shrd %%cl, %%edx, %0" : "=a" (rv) : "c" (th->th_x86_shift) : "edx"); return (rv); } static u_int __vdso_rdtsc32(void) { rdtsc_mb(); return (rdtsc32()); } #define HPET_DEV_MAP_MAX 10 static volatile char *hpet_dev_map[HPET_DEV_MAP_MAX]; static void __vdso_init_hpet(uint32_t u) { static const char devprefix[] = "/dev/hpet"; char devname[64], *c, *c1, t; volatile char *new_map, *old_map; unsigned int mode; uint32_t u1; int fd; c1 = c = stpcpy(devname, devprefix); u1 = u; do { *c++ = u1 % 10 + '0'; u1 /= 10; } while (u1 != 0); *c = '\0'; for (c--; c1 != c; c1++, c--) { t = *c1; *c1 = *c; *c = t; } old_map = hpet_dev_map[u]; if (old_map != NULL) return; /* * Explicitely check for the capability mode to avoid * triggering trap_enocap on the device open by absolute path. */ if ((cap_getmode(&mode) == 0 && mode != 0) || (fd = _open(devname, O_RDONLY)) == -1) { /* Prevent the caller from re-entering. */ atomic_cmpset_rel_ptr((volatile uintptr_t *)&hpet_dev_map[u], (uintptr_t)old_map, (uintptr_t)MAP_FAILED); return; } new_map = mmap(NULL, PAGE_SIZE, PROT_READ, MAP_SHARED, fd, 0); _close(fd); if (atomic_cmpset_rel_ptr((volatile uintptr_t *)&hpet_dev_map[u], (uintptr_t)old_map, (uintptr_t)new_map) == 0 && new_map != MAP_FAILED) munmap((void *)new_map, PAGE_SIZE); } #ifdef WANT_HYPERV #define HYPERV_REFTSC_DEVPATH "/dev/" HYPERV_REFTSC_DEVNAME /* * NOTE: * We use 'NULL' for this variable to indicate that initialization * is required. And if this variable is 'MAP_FAILED', then Hyper-V * reference TSC can not be used, e.g. in misconfigured jail. */ static struct hyperv_reftsc *hyperv_ref_tsc; static void __vdso_init_hyperv_tsc(void) { int fd; unsigned int mode; if (cap_getmode(&mode) == 0 && mode != 0) goto fail; fd = _open(HYPERV_REFTSC_DEVPATH, O_RDONLY); if (fd < 0) goto fail; hyperv_ref_tsc = mmap(NULL, sizeof(*hyperv_ref_tsc), PROT_READ, MAP_SHARED, fd, 0); _close(fd); return; fail: /* Prevent the caller from re-entering. */ hyperv_ref_tsc = MAP_FAILED; } static int __vdso_hyperv_tsc(struct hyperv_reftsc *tsc_ref, u_int *tc) { uint64_t disc, ret, tsc, scale; uint32_t seq; int64_t ofs; while ((seq = atomic_load_acq_int(&tsc_ref->tsc_seq)) != 0) { scale = tsc_ref->tsc_scale; ofs = tsc_ref->tsc_ofs; rdtsc_mb(); tsc = rdtsc(); /* ret = ((tsc * scale) >> 64) + ofs */ __asm__ __volatile__ ("mulq %3" : "=d" (ret), "=a" (disc) : "a" (tsc), "r" (scale)); ret += ofs; atomic_thread_fence_acq(); if (tsc_ref->tsc_seq == seq) { *tc = ret; return (0); } /* Sequence changed; re-sync. */ } return (ENOSYS); } #endif /* WANT_HYPERV */ #pragma weak __vdso_gettc int __vdso_gettc(const struct vdso_timehands *th, u_int *tc) { volatile char *map; uint32_t idx; 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: idx = th->th_x86_hpet_idx; if (idx >= HPET_DEV_MAP_MAX) return (ENOSYS); map = (volatile char *)atomic_load_acq_ptr( (volatile uintptr_t *)&hpet_dev_map[idx]); if (map == NULL) { __vdso_init_hpet(idx); map = (volatile char *)atomic_load_acq_ptr( (volatile uintptr_t *)&hpet_dev_map[idx]); } if (map == MAP_FAILED) return (ENOSYS); *tc = *(volatile uint32_t *)(map + HPET_MAIN_COUNTER); return (0); #ifdef WANT_HYPERV case VDSO_TH_ALGO_X86_HVTSC: if (hyperv_ref_tsc == NULL) __vdso_init_hyperv_tsc(); if (hyperv_ref_tsc == MAP_FAILED) return (ENOSYS); return (__vdso_hyperv_tsc(hyperv_ref_tsc, tc)); #endif default: return (ENOSYS); } } #pragma weak __vdso_gettimekeep int __vdso_gettimekeep(struct vdso_timekeep **tk) { return (_elf_aux_info(AT_TIMEKEEP, tk, sizeof(*tk))); }