2 * Copyright (c) 2012 Konstantin Belousov <kib@FreeBSD.org>
3 * Copyright (c) 2016, 2017, 2019 The FreeBSD Foundation
6 * Portions of this software were developed by Konstantin Belousov
7 * under sponsorship from the FreeBSD Foundation.
9 * Redistribution and use in source and binary forms, with or without
10 * modification, are permitted provided that the following conditions
12 * 1. Redistributions of source code must retain the above copyright
13 * notice, this list of conditions and the following disclaimer.
14 * 2. Redistributions in binary form must reproduce the above copyright
15 * notice, this list of conditions and the following disclaimer in the
16 * documentation and/or other materials provided with the distribution.
18 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
19 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
20 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
21 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
22 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
23 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
24 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
25 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
26 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
27 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31 #include <sys/cdefs.h>
32 __FBSDID("$FreeBSD$");
34 #include <sys/param.h>
35 #include "namespace.h"
36 #include <sys/capsicum.h>
38 #include <sys/fcntl.h>
45 #include "un-namespace.h"
46 #include <machine/atomic.h>
47 #include <machine/cpufunc.h>
48 #include <machine/specialreg.h>
49 #include <dev/acpica/acpi_hpet.h>
51 #include <dev/hyperv/hyperv.h>
53 #include <x86/ifunc.h>
54 #include "libc_private.h"
57 rdtsc_low(const struct vdso_timehands *th)
61 __asm __volatile("rdtsc; shrd %%cl, %%edx, %0"
62 : "=a" (rv) : "c" (th->th_x86_shift) : "edx");
67 rdtsc_low_mb_lfence(const struct vdso_timehands *th)
70 return (rdtsc_low(th));
74 rdtsc_low_mb_mfence(const struct vdso_timehands *th)
77 return (rdtsc_low(th));
81 rdtsc_low_mb_none(const struct vdso_timehands *th)
83 return (rdtsc_low(th));
87 rdtsc32_mb_lfence(void)
94 rdtsc32_mb_mfence(void)
101 rdtsc32_mb_none(void)
106 struct tsc_selector_tag {
107 u_int (*ts_rdtsc32)(void);
108 u_int (*ts_rdtsc_low)(const struct vdso_timehands *);
111 static const struct tsc_selector_tag tsc_selector[] = {
112 [0] = { /* Intel or AMD Zen+, LFENCE */
113 .ts_rdtsc32 = rdtsc32_mb_lfence,
114 .ts_rdtsc_low = rdtsc_low_mb_lfence,
116 [1] = { /* AMD, MFENCE */
117 .ts_rdtsc32 = rdtsc32_mb_mfence,
118 .ts_rdtsc_low = rdtsc_low_mb_mfence,
120 [2] = { /* No SSE2 */
121 .ts_rdtsc32 = rdtsc32_mb_none,
122 .ts_rdtsc_low = rdtsc_low_mb_none,
127 tsc_selector_idx(u_int cpu_feature)
129 u_int amd_feature, cpu_exthigh, cpu_id, p[4], v[3];
130 static const char amd_id[] = "AuthenticAMD";
131 static const char hygon_id[] = "HygonGenuine";
134 if (cpu_feature == 0)
135 return (2); /* should not happen due to RDTSC */
141 amd_cpu = memcmp(v, amd_id, sizeof(amd_id) - 1) == 0 ||
142 memcmp(v, hygon_id, sizeof(hygon_id) - 1) == 0;
147 if (cpu_feature != 0) {
148 do_cpuid(0x80000000, p);
153 if (cpu_exthigh >= 0x80000001) {
154 do_cpuid(0x80000001, p);
160 if ((cpu_feature & CPUID_SSE2) == 0)
162 return (amd_cpu ? 1 : 0);
165 DEFINE_UIFUNC(static, u_int, __vdso_gettc_rdtsc_low,
166 (const struct vdso_timehands *th))
168 return (tsc_selector[tsc_selector_idx(cpu_feature)].ts_rdtsc_low);
171 DEFINE_UIFUNC(static, u_int, __vdso_gettc_rdtsc32, (void))
173 return (tsc_selector[tsc_selector_idx(cpu_feature)].ts_rdtsc32);
176 #define HPET_DEV_MAP_MAX 10
177 static volatile char *hpet_dev_map[HPET_DEV_MAP_MAX];
180 __vdso_init_hpet(uint32_t u)
182 static const char devprefix[] = "/dev/hpet";
183 char devname[64], *c, *c1, t;
184 volatile char *new_map, *old_map;
189 c1 = c = stpcpy(devname, devprefix);
192 *c++ = u1 % 10 + '0';
196 for (c--; c1 != c; c1++, c--) {
202 old_map = hpet_dev_map[u];
207 * Explicitely check for the capability mode to avoid
208 * triggering trap_enocap on the device open by absolute path.
210 if ((cap_getmode(&mode) == 0 && mode != 0) ||
211 (fd = _open(devname, O_RDONLY)) == -1) {
212 /* Prevent the caller from re-entering. */
213 atomic_cmpset_rel_ptr((volatile uintptr_t *)&hpet_dev_map[u],
214 (uintptr_t)old_map, (uintptr_t)MAP_FAILED);
218 new_map = mmap(NULL, PAGE_SIZE, PROT_READ, MAP_SHARED, fd, 0);
220 if (atomic_cmpset_rel_ptr((volatile uintptr_t *)&hpet_dev_map[u],
221 (uintptr_t)old_map, (uintptr_t)new_map) == 0 &&
222 new_map != MAP_FAILED)
223 munmap((void *)new_map, PAGE_SIZE);
228 #define HYPERV_REFTSC_DEVPATH "/dev/" HYPERV_REFTSC_DEVNAME
232 * We use 'NULL' for this variable to indicate that initialization
233 * is required. And if this variable is 'MAP_FAILED', then Hyper-V
234 * reference TSC can not be used, e.g. in misconfigured jail.
236 static struct hyperv_reftsc *hyperv_ref_tsc;
239 __vdso_init_hyperv_tsc(void)
244 if (cap_getmode(&mode) == 0 && mode != 0)
247 fd = _open(HYPERV_REFTSC_DEVPATH, O_RDONLY);
250 hyperv_ref_tsc = mmap(NULL, sizeof(*hyperv_ref_tsc), PROT_READ,
256 /* Prevent the caller from re-entering. */
257 hyperv_ref_tsc = MAP_FAILED;
261 __vdso_hyperv_tsc(struct hyperv_reftsc *tsc_ref, u_int *tc)
263 uint64_t disc, ret, tsc, scale;
267 while ((seq = atomic_load_acq_int(&tsc_ref->tsc_seq)) != 0) {
268 scale = tsc_ref->tsc_scale;
269 ofs = tsc_ref->tsc_ofs;
271 mfence(); /* XXXKIB */
274 /* ret = ((tsc * scale) >> 64) + ofs */
275 __asm__ __volatile__ ("mulq %3" :
276 "=d" (ret), "=a" (disc) :
277 "a" (tsc), "r" (scale));
280 atomic_thread_fence_acq();
281 if (tsc_ref->tsc_seq == seq) {
286 /* Sequence changed; re-sync. */
291 #endif /* WANT_HYPERV */
293 #pragma weak __vdso_gettc
295 __vdso_gettc(const struct vdso_timehands *th, u_int *tc)
300 switch (th->th_algo) {
301 case VDSO_TH_ALGO_X86_TSC:
302 *tc = th->th_x86_shift > 0 ? __vdso_gettc_rdtsc_low(th) :
303 __vdso_gettc_rdtsc32();
305 case VDSO_TH_ALGO_X86_HPET:
306 idx = th->th_x86_hpet_idx;
307 if (idx >= HPET_DEV_MAP_MAX)
309 map = (volatile char *)atomic_load_acq_ptr(
310 (volatile uintptr_t *)&hpet_dev_map[idx]);
312 __vdso_init_hpet(idx);
313 map = (volatile char *)atomic_load_acq_ptr(
314 (volatile uintptr_t *)&hpet_dev_map[idx]);
316 if (map == MAP_FAILED)
318 *tc = *(volatile uint32_t *)(map + HPET_MAIN_COUNTER);
321 case VDSO_TH_ALGO_X86_HVTSC:
322 if (hyperv_ref_tsc == NULL)
323 __vdso_init_hyperv_tsc();
324 if (hyperv_ref_tsc == MAP_FAILED)
326 return (__vdso_hyperv_tsc(hyperv_ref_tsc, tc));
333 #pragma weak __vdso_gettimekeep
335 __vdso_gettimekeep(struct vdso_timekeep **tk)
338 return (_elf_aux_info(AT_TIMEKEEP, tk, sizeof(*tk)));