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| Current File : //sys/x86/x86/tsc.c |
/*-
* Copyright (c) 1998-2003 Poul-Henning Kamp
* All rights reserved.
*
* 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: release/9.1.0/sys/x86/x86/tsc.c 238910 2012-07-30 15:30:42Z jimharris $");
#include "opt_clock.h"
#include <sys/param.h>
#include <sys/bus.h>
#include <sys/cpu.h>
#include <sys/limits.h>
#include <sys/malloc.h>
#include <sys/systm.h>
#include <sys/sysctl.h>
#include <sys/time.h>
#include <sys/timetc.h>
#include <sys/kernel.h>
#include <sys/power.h>
#include <sys/smp.h>
#include <machine/clock.h>
#include <machine/cputypes.h>
#include <machine/md_var.h>
#include <machine/specialreg.h>
#include "cpufreq_if.h"
uint64_t tsc_freq;
int tsc_is_invariant;
int tsc_perf_stat;
static eventhandler_tag tsc_levels_tag, tsc_pre_tag, tsc_post_tag;
SYSCTL_INT(_kern_timecounter, OID_AUTO, invariant_tsc, CTLFLAG_RDTUN,
&tsc_is_invariant, 0, "Indicates whether the TSC is P-state invariant");
TUNABLE_INT("kern.timecounter.invariant_tsc", &tsc_is_invariant);
#ifdef SMP
static int smp_tsc;
SYSCTL_INT(_kern_timecounter, OID_AUTO, smp_tsc, CTLFLAG_RDTUN, &smp_tsc, 0,
"Indicates whether the TSC is safe to use in SMP mode");
TUNABLE_INT("kern.timecounter.smp_tsc", &smp_tsc);
#endif
static int tsc_disabled;
SYSCTL_INT(_machdep, OID_AUTO, disable_tsc, CTLFLAG_RDTUN, &tsc_disabled, 0,
"Disable x86 Time Stamp Counter");
TUNABLE_INT("machdep.disable_tsc", &tsc_disabled);
static int tsc_skip_calibration;
SYSCTL_INT(_machdep, OID_AUTO, disable_tsc_calibration, CTLFLAG_RDTUN,
&tsc_skip_calibration, 0, "Disable TSC frequency calibration");
TUNABLE_INT("machdep.disable_tsc_calibration", &tsc_skip_calibration);
static void tsc_freq_changed(void *arg, const struct cf_level *level,
int status);
static void tsc_freq_changing(void *arg, const struct cf_level *level,
int *status);
static unsigned tsc_get_timecount(struct timecounter *tc);
static unsigned tsc_get_timecount_low(struct timecounter *tc);
static void tsc_levels_changed(void *arg, int unit);
static struct timecounter tsc_timecounter = {
tsc_get_timecount, /* get_timecount */
0, /* no poll_pps */
~0u, /* counter_mask */
0, /* frequency */
"TSC", /* name */
800, /* quality (adjusted in code) */
};
#define VMW_HVMAGIC 0x564d5868
#define VMW_HVPORT 0x5658
#define VMW_HVCMD_GETVERSION 10
#define VMW_HVCMD_GETHZ 45
static __inline void
vmware_hvcall(u_int cmd, u_int *p)
{
__asm __volatile("inl %w3, %0"
: "=a" (p[0]), "=b" (p[1]), "=c" (p[2]), "=d" (p[3])
: "0" (VMW_HVMAGIC), "1" (UINT_MAX), "2" (cmd), "3" (VMW_HVPORT)
: "memory");
}
static int
tsc_freq_vmware(void)
{
char hv_sig[13];
u_int regs[4];
char *p;
u_int hv_high;
int i;
/*
* [RFC] CPUID usage for interaction between Hypervisors and Linux.
* http://lkml.org/lkml/2008/10/1/246
*
* KB1009458: Mechanisms to determine if software is running in
* a VMware virtual machine
* http://kb.vmware.com/kb/1009458
*/
hv_high = 0;
if ((cpu_feature2 & CPUID2_HV) != 0) {
do_cpuid(0x40000000, regs);
hv_high = regs[0];
for (i = 1, p = hv_sig; i < 4; i++, p += sizeof(regs) / 4)
memcpy(p, ®s[i], sizeof(regs[i]));
*p = '\0';
if (bootverbose) {
/*
* HV vendor ID string
* ------------+--------------
* KVM "KVMKVMKVM"
* Microsoft "Microsoft Hv"
* VMware "VMwareVMware"
* Xen "XenVMMXenVMM"
*/
printf("Hypervisor: Origin = \"%s\"\n", hv_sig);
}
if (strncmp(hv_sig, "VMwareVMware", 12) != 0)
return (0);
} else {
p = getenv("smbios.system.serial");
if (p == NULL)
return (0);
if (strncmp(p, "VMware-", 7) != 0 &&
strncmp(p, "VMW", 3) != 0) {
freeenv(p);
return (0);
}
freeenv(p);
vmware_hvcall(VMW_HVCMD_GETVERSION, regs);
if (regs[1] != VMW_HVMAGIC)
return (0);
}
if (hv_high >= 0x40000010) {
do_cpuid(0x40000010, regs);
tsc_freq = regs[0] * 1000;
} else {
vmware_hvcall(VMW_HVCMD_GETHZ, regs);
if (regs[1] != UINT_MAX)
tsc_freq = regs[0] | ((uint64_t)regs[1] << 32);
}
tsc_is_invariant = 1;
return (1);
}
static void
tsc_freq_intel(void)
{
char brand[48];
u_int regs[4];
uint64_t freq;
char *p;
u_int i;
/*
* Intel Processor Identification and the CPUID Instruction
* Application Note 485.
* http://www.intel.com/assets/pdf/appnote/241618.pdf
*/
if (cpu_exthigh >= 0x80000004) {
p = brand;
for (i = 0x80000002; i < 0x80000005; i++) {
do_cpuid(i, regs);
memcpy(p, regs, sizeof(regs));
p += sizeof(regs);
}
p = NULL;
for (i = 0; i < sizeof(brand) - 1; i++)
if (brand[i] == 'H' && brand[i + 1] == 'z')
p = brand + i;
if (p != NULL) {
p -= 5;
switch (p[4]) {
case 'M':
i = 1;
break;
case 'G':
i = 1000;
break;
case 'T':
i = 1000000;
break;
default:
return;
}
#define C2D(c) ((c) - '0')
if (p[1] == '.') {
freq = C2D(p[0]) * 1000;
freq += C2D(p[2]) * 100;
freq += C2D(p[3]) * 10;
freq *= i * 1000;
} else {
freq = C2D(p[0]) * 1000;
freq += C2D(p[1]) * 100;
freq += C2D(p[2]) * 10;
freq += C2D(p[3]);
freq *= i * 1000000;
}
#undef C2D
tsc_freq = freq;
}
}
}
static void
probe_tsc_freq(void)
{
u_int regs[4];
uint64_t tsc1, tsc2;
if (cpu_high >= 6) {
do_cpuid(6, regs);
if ((regs[2] & CPUID_PERF_STAT) != 0) {
/*
* XXX Some emulators expose host CPUID without actual
* support for these MSRs. We must test whether they
* really work.
*/
wrmsr(MSR_MPERF, 0);
wrmsr(MSR_APERF, 0);
DELAY(10);
if (rdmsr(MSR_MPERF) > 0 && rdmsr(MSR_APERF) > 0)
tsc_perf_stat = 1;
}
}
if (tsc_freq_vmware())
return;
switch (cpu_vendor_id) {
case CPU_VENDOR_AMD:
if ((amd_pminfo & AMDPM_TSC_INVARIANT) != 0 ||
(vm_guest == VM_GUEST_NO &&
CPUID_TO_FAMILY(cpu_id) >= 0x10))
tsc_is_invariant = 1;
break;
case CPU_VENDOR_INTEL:
if ((amd_pminfo & AMDPM_TSC_INVARIANT) != 0 ||
(vm_guest == VM_GUEST_NO &&
((CPUID_TO_FAMILY(cpu_id) == 0x6 &&
CPUID_TO_MODEL(cpu_id) >= 0xe) ||
(CPUID_TO_FAMILY(cpu_id) == 0xf &&
CPUID_TO_MODEL(cpu_id) >= 0x3))))
tsc_is_invariant = 1;
break;
case CPU_VENDOR_CENTAUR:
if (vm_guest == VM_GUEST_NO &&
CPUID_TO_FAMILY(cpu_id) == 0x6 &&
CPUID_TO_MODEL(cpu_id) >= 0xf &&
(rdmsr(0x1203) & 0x100000000ULL) == 0)
tsc_is_invariant = 1;
break;
}
if (tsc_skip_calibration) {
if (cpu_vendor_id == CPU_VENDOR_INTEL)
tsc_freq_intel();
return;
}
if (bootverbose)
printf("Calibrating TSC clock ... ");
tsc1 = rdtsc();
DELAY(1000000);
tsc2 = rdtsc();
tsc_freq = tsc2 - tsc1;
if (bootverbose)
printf("TSC clock: %ju Hz\n", (intmax_t)tsc_freq);
}
void
init_TSC(void)
{
if ((cpu_feature & CPUID_TSC) == 0 || tsc_disabled)
return;
probe_tsc_freq();
/*
* Inform CPU accounting about our boot-time clock rate. This will
* be updated if someone loads a cpufreq driver after boot that
* discovers a new max frequency.
*/
if (tsc_freq != 0)
set_cputicker(rdtsc, tsc_freq, !tsc_is_invariant);
if (tsc_is_invariant)
return;
/* Register to find out about changes in CPU frequency. */
tsc_pre_tag = EVENTHANDLER_REGISTER(cpufreq_pre_change,
tsc_freq_changing, NULL, EVENTHANDLER_PRI_FIRST);
tsc_post_tag = EVENTHANDLER_REGISTER(cpufreq_post_change,
tsc_freq_changed, NULL, EVENTHANDLER_PRI_FIRST);
tsc_levels_tag = EVENTHANDLER_REGISTER(cpufreq_levels_changed,
tsc_levels_changed, NULL, EVENTHANDLER_PRI_ANY);
}
#ifdef SMP
/* rmb is required here because rdtsc is not a serializing instruction. */
#define TSC_READ(x) \
static void \
tsc_read_##x(void *arg) \
{ \
uint32_t *tsc = arg; \
u_int cpu = PCPU_GET(cpuid); \
\
rmb(); \
tsc[cpu * 3 + x] = rdtsc32(); \
}
TSC_READ(0)
TSC_READ(1)
TSC_READ(2)
#undef TSC_READ
#define N 1000
static void
comp_smp_tsc(void *arg)
{
uint32_t *tsc;
int32_t d1, d2;
u_int cpu = PCPU_GET(cpuid);
u_int i, j, size;
size = (mp_maxid + 1) * 3;
for (i = 0, tsc = arg; i < N; i++, tsc += size)
CPU_FOREACH(j) {
if (j == cpu)
continue;
d1 = tsc[cpu * 3 + 1] - tsc[j * 3];
d2 = tsc[cpu * 3 + 2] - tsc[j * 3 + 1];
if (d1 <= 0 || d2 <= 0) {
smp_tsc = 0;
return;
}
}
}
static int
test_smp_tsc(void)
{
uint32_t *data, *tsc;
u_int i, size;
if (!smp_tsc && !tsc_is_invariant)
return (-100);
size = (mp_maxid + 1) * 3;
data = malloc(sizeof(*data) * size * N, M_TEMP, M_WAITOK);
for (i = 0, tsc = data; i < N; i++, tsc += size)
smp_rendezvous(tsc_read_0, tsc_read_1, tsc_read_2, tsc);
smp_tsc = 1; /* XXX */
smp_rendezvous(smp_no_rendevous_barrier, comp_smp_tsc,
smp_no_rendevous_barrier, data);
free(data, M_TEMP);
if (bootverbose)
printf("SMP: %sed TSC synchronization test\n",
smp_tsc ? "pass" : "fail");
if (smp_tsc && tsc_is_invariant) {
switch (cpu_vendor_id) {
case CPU_VENDOR_AMD:
/*
* Starting with Family 15h processors, TSC clock
* source is in the north bridge. Check whether
* we have a single-socket/multi-core platform.
* XXX Need more work for complex cases.
*/
if (CPUID_TO_FAMILY(cpu_id) < 0x15 ||
(amd_feature2 & AMDID2_CMP) == 0 ||
smp_cpus > (cpu_procinfo2 & AMDID_CMP_CORES) + 1)
break;
return (1000);
case CPU_VENDOR_INTEL:
/*
* XXX Assume Intel platforms have synchronized TSCs.
*/
return (1000);
}
return (800);
}
return (-100);
}
#undef N
#endif /* SMP */
static void
init_TSC_tc(void)
{
uint64_t max_freq;
int shift;
if ((cpu_feature & CPUID_TSC) == 0 || tsc_disabled)
return;
/*
* Limit timecounter frequency to fit in an int and prevent it from
* overflowing too fast.
*/
max_freq = UINT_MAX;
/*
* We can not use the TSC if we support APM. Precise timekeeping
* on an APM'ed machine is at best a fools pursuit, since
* any and all of the time spent in various SMM code can't
* be reliably accounted for. Reading the RTC is your only
* source of reliable time info. The i8254 loses too, of course,
* but we need to have some kind of time...
* We don't know at this point whether APM is going to be used
* or not, nor when it might be activated. Play it safe.
*/
if (power_pm_get_type() == POWER_PM_TYPE_APM) {
tsc_timecounter.tc_quality = -1000;
if (bootverbose)
printf("TSC timecounter disabled: APM enabled.\n");
goto init;
}
/*
* We cannot use the TSC if it stops incrementing in deep sleep.
* Currently only Intel CPUs are known for this problem unless
* the invariant TSC bit is set.
*/
if (cpu_can_deep_sleep && cpu_vendor_id == CPU_VENDOR_INTEL &&
(amd_pminfo & AMDPM_TSC_INVARIANT) == 0) {
tsc_timecounter.tc_quality = -1000;
tsc_timecounter.tc_flags |= TC_FLAGS_C3STOP;
if (bootverbose)
printf("TSC timecounter disabled: C3 enabled.\n");
goto init;
}
#ifdef SMP
/*
* We can not use the TSC in SMP mode unless the TSCs on all CPUs are
* synchronized. If the user is sure that the system has synchronized
* TSCs, set kern.timecounter.smp_tsc tunable to a non-zero value.
* We also limit the frequency even lower to avoid "temporal anomalies"
* as much as possible. The TSC seems unreliable in virtualized SMP
* environments, so it is set to a negative quality in those cases.
*/
if (smp_cpus > 1) {
if (vm_guest != 0) {
tsc_timecounter.tc_quality = -100;
} else {
tsc_timecounter.tc_quality = test_smp_tsc();
max_freq >>= 8;
}
} else
#endif
if (tsc_is_invariant)
tsc_timecounter.tc_quality = 1000;
init:
for (shift = 0; shift < 31 && (tsc_freq >> shift) > max_freq; shift++)
;
if (shift > 0) {
tsc_timecounter.tc_get_timecount = tsc_get_timecount_low;
tsc_timecounter.tc_name = "TSC-low";
if (bootverbose)
printf("TSC timecounter discards lower %d bit(s)\n",
shift);
}
if (tsc_freq != 0) {
tsc_timecounter.tc_frequency = tsc_freq >> shift;
tsc_timecounter.tc_priv = (void *)(intptr_t)shift;
tc_init(&tsc_timecounter);
}
}
SYSINIT(tsc_tc, SI_SUB_SMP, SI_ORDER_ANY, init_TSC_tc, NULL);
/*
* When cpufreq levels change, find out about the (new) max frequency. We
* use this to update CPU accounting in case it got a lower estimate at boot.
*/
static void
tsc_levels_changed(void *arg, int unit)
{
device_t cf_dev;
struct cf_level *levels;
int count, error;
uint64_t max_freq;
/* Only use values from the first CPU, assuming all are equal. */
if (unit != 0)
return;
/* Find the appropriate cpufreq device instance. */
cf_dev = devclass_get_device(devclass_find("cpufreq"), unit);
if (cf_dev == NULL) {
printf("tsc_levels_changed() called but no cpufreq device?\n");
return;
}
/* Get settings from the device and find the max frequency. */
count = 64;
levels = malloc(count * sizeof(*levels), M_TEMP, M_NOWAIT);
if (levels == NULL)
return;
error = CPUFREQ_LEVELS(cf_dev, levels, &count);
if (error == 0 && count != 0) {
max_freq = (uint64_t)levels[0].total_set.freq * 1000000;
set_cputicker(rdtsc, max_freq, 1);
} else
printf("tsc_levels_changed: no max freq found\n");
free(levels, M_TEMP);
}
/*
* If the TSC timecounter is in use, veto the pending change. It may be
* possible in the future to handle a dynamically-changing timecounter rate.
*/
static void
tsc_freq_changing(void *arg, const struct cf_level *level, int *status)
{
if (*status != 0 || timecounter != &tsc_timecounter)
return;
printf("timecounter TSC must not be in use when "
"changing frequencies; change denied\n");
*status = EBUSY;
}
/* Update TSC freq with the value indicated by the caller. */
static void
tsc_freq_changed(void *arg, const struct cf_level *level, int status)
{
uint64_t freq;
/* If there was an error during the transition, don't do anything. */
if (tsc_disabled || status != 0)
return;
/* Total setting for this level gives the new frequency in MHz. */
freq = (uint64_t)level->total_set.freq * 1000000;
atomic_store_rel_64(&tsc_freq, freq);
tsc_timecounter.tc_frequency =
freq >> (int)(intptr_t)tsc_timecounter.tc_priv;
}
static int
sysctl_machdep_tsc_freq(SYSCTL_HANDLER_ARGS)
{
int error;
uint64_t freq;
freq = atomic_load_acq_64(&tsc_freq);
if (freq == 0)
return (EOPNOTSUPP);
error = sysctl_handle_64(oidp, &freq, 0, req);
if (error == 0 && req->newptr != NULL) {
atomic_store_rel_64(&tsc_freq, freq);
atomic_store_rel_64(&tsc_timecounter.tc_frequency,
freq >> (int)(intptr_t)tsc_timecounter.tc_priv);
}
return (error);
}
SYSCTL_PROC(_machdep, OID_AUTO, tsc_freq, CTLTYPE_U64 | CTLFLAG_RW,
0, 0, sysctl_machdep_tsc_freq, "QU", "Time Stamp Counter frequency");
static u_int
tsc_get_timecount(struct timecounter *tc __unused)
{
return (rdtsc32());
}
static u_int
tsc_get_timecount_low(struct timecounter *tc)
{
uint32_t rv;
__asm __volatile("rdtsc; shrd %%cl, %%edx, %0"
: "=a" (rv) : "c" ((int)(intptr_t)tc->tc_priv) : "edx");
return (rv);
}