1 /*- 2 * Copyright (c) 2009 Adrian Chadd 3 * Copyright (c) 2012 Spectra Logic Corporation 4 * Copyright (c) 2014 Bryan Venteicher 5 * All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 19 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 26 * SUCH DAMAGE. 27 */ 28 29 #include <sys/cdefs.h> 30 __FBSDID("$FreeBSD$"); 31 32 #include <sys/param.h> 33 #include <sys/systm.h> 34 #include <sys/bus.h> 35 #include <sys/clock.h> 36 #include <sys/conf.h> 37 #include <sys/fcntl.h> 38 #include <sys/limits.h> 39 #include <sys/mman.h> 40 #include <sys/proc.h> 41 #include <sys/smp.h> 42 #include <sys/sysctl.h> 43 #include <sys/vdso.h> 44 45 #include <vm/vm.h> 46 #include <vm/pmap.h> 47 48 #include <machine/atomic.h> 49 #include <machine/cpufunc.h> 50 #include <machine/md_var.h> 51 #include <machine/pvclock.h> 52 53 /* 54 * Last system time. This is used to guarantee a monotonically non-decreasing 55 * clock for the kernel codepath and approximate the same for the vDSO codepath. 56 * In theory, this should be unnecessary absent hypervisor bug(s) and/or what 57 * should be rare cases where TSC jitter may still be visible despite the 58 * hypervisor's best efforts. 59 */ 60 static volatile uint64_t pvclock_last_systime; 61 62 static uint64_t pvclock_getsystime(struct pvclock *pvc); 63 static void pvclock_read_time_info( 64 struct pvclock_vcpu_time_info *ti, uint64_t *ns, uint8_t *flags); 65 static void pvclock_read_wall_clock(struct pvclock_wall_clock *wc, 66 struct timespec *ts); 67 static u_int pvclock_tc_get_timecount(struct timecounter *tc); 68 static uint32_t pvclock_tc_vdso_timehands( 69 struct vdso_timehands *vdso_th, struct timecounter *tc); 70 #ifdef COMPAT_FREEBSD32 71 static uint32_t pvclock_tc_vdso_timehands32( 72 struct vdso_timehands32 *vdso_th, struct timecounter *tc); 73 #endif 74 75 static d_open_t pvclock_cdev_open; 76 static d_mmap_t pvclock_cdev_mmap; 77 78 static struct cdevsw pvclock_cdev_cdevsw = { 79 .d_version = D_VERSION, 80 .d_name = PVCLOCK_CDEVNAME, 81 .d_open = pvclock_cdev_open, 82 .d_mmap = pvclock_cdev_mmap, 83 }; 84 85 void 86 pvclock_resume(void) 87 { 88 atomic_store_rel_64(&pvclock_last_systime, 0); 89 } 90 91 uint64_t 92 pvclock_tsc_freq(struct pvclock_vcpu_time_info *ti) 93 { 94 uint64_t freq; 95 96 freq = (1000000000ULL << 32) / ti->tsc_to_system_mul; 97 if (ti->tsc_shift < 0) 98 freq <<= -ti->tsc_shift; 99 else 100 freq >>= ti->tsc_shift; 101 return (freq); 102 } 103 104 static void 105 pvclock_read_time_info(struct pvclock_vcpu_time_info *ti, 106 uint64_t *ns, uint8_t *flags) 107 { 108 uint64_t delta; 109 uint32_t version; 110 111 do { 112 version = atomic_load_acq_32(&ti->version); 113 delta = rdtsc_ordered() - ti->tsc_timestamp; 114 *ns = ti->system_time + pvclock_scale_delta(delta, 115 ti->tsc_to_system_mul, ti->tsc_shift); 116 *flags = ti->flags; 117 atomic_thread_fence_acq(); 118 } while ((ti->version & 1) != 0 || ti->version != version); 119 } 120 121 static void 122 pvclock_read_wall_clock(struct pvclock_wall_clock *wc, struct timespec *ts) 123 { 124 uint32_t version; 125 126 do { 127 version = atomic_load_acq_32(&wc->version); 128 ts->tv_sec = wc->sec; 129 ts->tv_nsec = wc->nsec; 130 atomic_thread_fence_acq(); 131 } while ((wc->version & 1) != 0 || wc->version != version); 132 } 133 134 static uint64_t 135 pvclock_getsystime(struct pvclock *pvc) 136 { 137 uint64_t now, last, ret; 138 uint8_t flags; 139 140 critical_enter(); 141 pvclock_read_time_info(&pvc->timeinfos[curcpu], &now, &flags); 142 ret = now; 143 if ((flags & PVCLOCK_FLAG_TSC_STABLE) == 0) { 144 last = atomic_load_acq_64(&pvclock_last_systime); 145 do { 146 if (last > now) { 147 ret = last; 148 break; 149 } 150 } while (!atomic_fcmpset_rel_64(&pvclock_last_systime, &last, 151 now)); 152 } 153 critical_exit(); 154 return (ret); 155 } 156 157 /* 158 * NOTE: Transitional-only; this should be removed after 'dev/xen/timer/timer.c' 159 * has been migrated to the 'struct pvclock' API. 160 */ 161 uint64_t 162 pvclock_get_timecount(struct pvclock_vcpu_time_info *ti) 163 { 164 uint64_t now, last, ret; 165 uint8_t flags; 166 167 pvclock_read_time_info(ti, &now, &flags); 168 ret = now; 169 if ((flags & PVCLOCK_FLAG_TSC_STABLE) == 0) { 170 last = atomic_load_acq_64(&pvclock_last_systime); 171 do { 172 if (last > now) { 173 ret = last; 174 break; 175 } 176 } while (!atomic_fcmpset_rel_64(&pvclock_last_systime, &last, 177 now)); 178 } 179 return (ret); 180 } 181 182 /* 183 * NOTE: Transitional-only; this should be removed after 'dev/xen/timer/timer.c' 184 * has been migrated to the 'struct pvclock' API. 185 */ 186 void 187 pvclock_get_wallclock(struct pvclock_wall_clock *wc, struct timespec *ts) 188 { 189 pvclock_read_wall_clock(wc, ts); 190 } 191 192 static int 193 pvclock_cdev_open(struct cdev *dev, int oflags, int devtype, struct thread *td) 194 { 195 if (oflags & FWRITE) 196 return (EPERM); 197 return (0); 198 } 199 200 static int 201 pvclock_cdev_mmap(struct cdev *dev, vm_ooffset_t offset, vm_paddr_t *paddr, 202 int nprot, vm_memattr_t *memattr) 203 { 204 if (offset >= mp_ncpus * sizeof(struct pvclock_vcpu_time_info)) 205 return (EINVAL); 206 if (PROT_EXTRACT(nprot) != PROT_READ) 207 return (EACCES); 208 *paddr = vtophys((uintptr_t)dev->si_drv1 + offset); 209 *memattr = VM_MEMATTR_DEFAULT; 210 return (0); 211 } 212 213 static u_int 214 pvclock_tc_get_timecount(struct timecounter *tc) 215 { 216 struct pvclock *pvc = tc->tc_priv; 217 218 return (pvclock_getsystime(pvc) & UINT_MAX); 219 } 220 221 static uint32_t 222 pvclock_tc_vdso_timehands(struct vdso_timehands *vdso_th, 223 struct timecounter *tc) 224 { 225 struct pvclock *pvc = tc->tc_priv; 226 227 vdso_th->th_algo = VDSO_TH_ALGO_X86_PVCLK; 228 vdso_th->th_x86_shift = 0; 229 vdso_th->th_x86_hpet_idx = 0; 230 vdso_th->th_x86_pvc_last_systime = 231 atomic_load_acq_64(&pvclock_last_systime); 232 vdso_th->th_x86_pvc_stable_mask = !pvc->vdso_force_unstable && 233 pvc->stable_flag_supported ? PVCLOCK_FLAG_TSC_STABLE : 0; 234 bzero(vdso_th->th_res, sizeof(vdso_th->th_res)); 235 return (pvc->cdev != NULL && amd_feature & AMDID_RDTSCP); 236 } 237 238 #ifdef COMPAT_FREEBSD32 239 static uint32_t 240 pvclock_tc_vdso_timehands32(struct vdso_timehands32 *vdso_th, 241 struct timecounter *tc) 242 { 243 struct pvclock *pvc = tc->tc_priv; 244 245 vdso_th->th_algo = VDSO_TH_ALGO_X86_PVCLK; 246 vdso_th->th_x86_shift = 0; 247 vdso_th->th_x86_hpet_idx = 0; 248 vdso_th->th_x86_pvc_last_systime = 249 atomic_load_acq_64(&pvclock_last_systime); 250 vdso_th->th_x86_pvc_stable_mask = !pvc->vdso_force_unstable && 251 pvc->stable_flag_supported ? PVCLOCK_FLAG_TSC_STABLE : 0; 252 bzero(vdso_th->th_res, sizeof(vdso_th->th_res)); 253 return (pvc->cdev != NULL && amd_feature & AMDID_RDTSCP); 254 } 255 #endif 256 257 void 258 pvclock_gettime(struct pvclock *pvc, struct timespec *ts) 259 { 260 struct timespec system_ts; 261 uint64_t system_ns; 262 263 pvclock_read_wall_clock(pvc->get_wallclock(pvc->get_wallclock_arg), ts); 264 system_ns = pvclock_getsystime(pvc); 265 system_ts.tv_sec = system_ns / 1000000000ULL; 266 system_ts.tv_nsec = system_ns % 1000000000ULL; 267 timespecadd(ts, &system_ts, ts); 268 } 269 270 void 271 pvclock_init(struct pvclock *pvc, device_t dev, const char *tc_name, 272 int tc_quality, u_int tc_flags) 273 { 274 struct make_dev_args mda; 275 int err; 276 277 KASSERT(((uintptr_t)pvc->timeinfos & PAGE_MASK) == 0, 278 ("Specified time info page(s) address is not page-aligned.")); 279 280 /* Set up vDSO stable-flag suppression test facility: */ 281 pvc->vdso_force_unstable = false; 282 SYSCTL_ADD_BOOL(device_get_sysctl_ctx(dev), 283 SYSCTL_CHILDREN(device_get_sysctl_tree(dev)), OID_AUTO, 284 "vdso_force_unstable", CTLFLAG_RW, &pvc->vdso_force_unstable, 0, 285 "Forcibly deassert stable flag in vDSO codepath"); 286 287 /* Set up timecounter and timecounter-supporting members: */ 288 pvc->tc.tc_get_timecount = pvclock_tc_get_timecount; 289 pvc->tc.tc_poll_pps = NULL; 290 pvc->tc.tc_counter_mask = ~0U; 291 pvc->tc.tc_frequency = 1000000000ULL; 292 pvc->tc.tc_name = tc_name; 293 pvc->tc.tc_quality = tc_quality; 294 pvc->tc.tc_flags = tc_flags; 295 pvc->tc.tc_priv = pvc; 296 pvc->tc.tc_fill_vdso_timehands = pvclock_tc_vdso_timehands; 297 #ifdef COMPAT_FREEBSD32 298 pvc->tc.tc_fill_vdso_timehands32 = pvclock_tc_vdso_timehands32; 299 #endif 300 301 /* Set up cdev for userspace mmapping of vCPU 0 time info page: */ 302 make_dev_args_init(&mda); 303 mda.mda_devsw = &pvclock_cdev_cdevsw; 304 mda.mda_uid = UID_ROOT; 305 mda.mda_gid = GID_WHEEL; 306 mda.mda_mode = 0444; 307 mda.mda_si_drv1 = pvc->timeinfos; 308 err = make_dev_s(&mda, &pvc->cdev, PVCLOCK_CDEVNAME); 309 if (err != 0) { 310 device_printf(dev, "Could not create /dev/%s, error %d. Fast " 311 "time of day will be unavailable for this timecounter.\n", 312 PVCLOCK_CDEVNAME, err); 313 KASSERT(pvc->cdev == NULL, 314 ("Failed make_dev_s() unexpectedly inited cdev.")); 315 } 316 317 /* Register timecounter: */ 318 tc_init(&pvc->tc); 319 320 /* 321 * Register wallclock: 322 * The RTC registration API expects a resolution in microseconds; 323 * pvclock's 1ns resolution is rounded up to 1us. 324 */ 325 clock_register(dev, 1); 326 } 327 328 int 329 pvclock_destroy(struct pvclock *pvc) 330 { 331 /* 332 * Not currently possible since there is no teardown counterpart of 333 * 'tc_init()'. 334 */ 335 return (EBUSY); 336 } 337