diff options
author | kib <kib@FreeBSD.org> | 2012-08-01 17:26:22 +0000 |
---|---|---|
committer | kib <kib@FreeBSD.org> | 2012-08-01 17:26:22 +0000 |
commit | 58f7ae85c74dabb278901c6e1c4afae9578733f2 (patch) | |
tree | 430222b79641e7b9564fdc26c3329ad61c53b8e9 /sys/x86 | |
parent | 36babd37ca7f9addb238b81428902b296c388a0b (diff) | |
download | FreeBSD-src-58f7ae85c74dabb278901c6e1c4afae9578733f2.zip FreeBSD-src-58f7ae85c74dabb278901c6e1c4afae9578733f2.tar.gz |
diff --git a/sys/x86/x86/tsc.c b/sys/x86/x86/tsc.c
index c253a96..3d8bd30 100644
--- a/sys/x86/x86/tsc.c
+++ b/sys/x86/x86/tsc.c
@@ -82,7 +82,11 @@ static void tsc_freq_changed(void *arg, const struct cf_level *level,
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 inline unsigned tsc_get_timecount_low(struct timecounter *tc);
+static unsigned tsc_get_timecount_lfence(struct timecounter *tc);
+static unsigned tsc_get_timecount_low_lfence(struct timecounter *tc);
+static unsigned tsc_get_timecount_mfence(struct timecounter *tc);
+static unsigned tsc_get_timecount_low_mfence(struct timecounter *tc);
static void tsc_levels_changed(void *arg, int unit);
static struct timecounter tsc_timecounter = {
@@ -262,6 +266,10 @@ probe_tsc_freq(void)
(vm_guest == VM_GUEST_NO &&
CPUID_TO_FAMILY(cpu_id) >= 0x10))
tsc_is_invariant = 1;
+ if (cpu_feature & CPUID_SSE2) {
+ tsc_timecounter.tc_get_timecount =
+ tsc_get_timecount_mfence;
+ }
break;
case CPU_VENDOR_INTEL:
if ((amd_pminfo & AMDPM_TSC_INVARIANT) != 0 ||
@@ -271,6 +279,10 @@ probe_tsc_freq(void)
(CPUID_TO_FAMILY(cpu_id) == 0xf &&
CPUID_TO_MODEL(cpu_id) >= 0x3))))
tsc_is_invariant = 1;
+ if (cpu_feature & CPUID_SSE2) {
+ tsc_timecounter.tc_get_timecount =
+ tsc_get_timecount_lfence;
+ }
break;
case CPU_VENDOR_CENTAUR:
if (vm_guest == VM_GUEST_NO &&
@@ -278,6 +290,10 @@ probe_tsc_freq(void)
CPUID_TO_MODEL(cpu_id) >= 0xf &&
(rdmsr(0x1203) & 0x100000000ULL) == 0)
tsc_is_invariant = 1;
+ if (cpu_feature & CPUID_SSE2) {
+ tsc_timecounter.tc_get_timecount =
+ tsc_get_timecount_lfence;
+ }
break;
}
@@ -328,16 +344,31 @@ init_TSC(void)
#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(); \
+/*
+ * RDTSC is not a serializing instruction, and does not drain
+ * instruction stream, so we need to drain the stream before executing
+ * it. It could be fixed by use of RDTSCP, except the instruction is
+ * not available everywhere.
+ *
+ * Use CPUID for draining in the boot-time SMP constistency test. The
+ * timecounters use MFENCE for AMD CPUs, and LFENCE for others (Intel
+ * and VIA) when SSE2 is present, and nothing on older machines which
+ * also do not issue RDTSC prematurely. There, testing for SSE2 and
+ * vendor is too cumbersome, and we learn about TSC presence from
+ * CPUID.
+ *
+ * Do not use do_cpuid(), since we do not need CPUID results, which
+ * have to be written into memory with do_cpuid().
+ */
+#define TSC_READ(x) \
+static void \
+tsc_read_##x(void *arg) \
+{ \
+ uint32_t *tsc = arg; \
+ u_int cpu = PCPU_GET(cpuid); \
+ \
+ __asm __volatile("cpuid" : : : "eax", "ebx", "ecx", "edx"); \
+ tsc[cpu * 3 + x] = rdtsc32(); \
}
TSC_READ(0)
TSC_READ(1)
@@ -487,7 +518,16 @@ init:
for (shift = 0; shift < 31 && (tsc_freq >> shift) > max_freq; shift++)
;
if (shift > 0) {
- tsc_timecounter.tc_get_timecount = tsc_get_timecount_low;
+ if (cpu_feature & CPUID_SSE2) {
+ if (cpu_vendor_id == CPU_VENDOR_AMD) {
+ tsc_timecounter.tc_get_timecount =
+ tsc_get_timecount_low_mfence;
+ } else {
+ tsc_timecounter.tc_get_timecount =
+ tsc_get_timecount_low_lfence;
+ }
+ } else
+ 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",
@@ -599,16 +639,48 @@ tsc_get_timecount(struct timecounter *tc __unused)
return (rdtsc32());
}
-static u_int
+static inline 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");
+ : "=a" (rv) : "c" ((int)(intptr_t)tc->tc_priv) : "edx");
return (rv);
}
+static u_int
+tsc_get_timecount_lfence(struct timecounter *tc __unused)
+{
+
+ lfence();
+ return (rdtsc32());
+}
+
+static u_int
+tsc_get_timecount_low_lfence(struct timecounter *tc)
+{
+
+ lfence();
+ return (tsc_get_timecount_low(tc));
+}
+
+static u_int
+tsc_get_timecount_mfence(struct timecounter *tc __unused)
+{
+
+ mfence();
+ return (rdtsc32());
+}
+
+static u_int
+tsc_get_timecount_low_mfence(struct timecounter *tc)
+{
+
+ mfence();
+ return (tsc_get_timecount_low(tc));
+}
+
uint32_t
cpu_fill_vdso_timehands(struct vdso_timehands *vdso_th)
{
Diffstat (limited to 'sys/x86')
-rw-r--r-- | sys/x86/x86/tsc.c | 100 |
1 files changed, 86 insertions, 14 deletions
diff --git a/sys/x86/x86/tsc.c b/sys/x86/x86/tsc.c index c253a96..3d8bd30 100644 --- a/sys/x86/x86/tsc.c +++ b/sys/x86/x86/tsc.c @@ -82,7 +82,11 @@ static void tsc_freq_changed(void *arg, const struct cf_level *level, 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 inline unsigned tsc_get_timecount_low(struct timecounter *tc); +static unsigned tsc_get_timecount_lfence(struct timecounter *tc); +static unsigned tsc_get_timecount_low_lfence(struct timecounter *tc); +static unsigned tsc_get_timecount_mfence(struct timecounter *tc); +static unsigned tsc_get_timecount_low_mfence(struct timecounter *tc); static void tsc_levels_changed(void *arg, int unit); static struct timecounter tsc_timecounter = { @@ -262,6 +266,10 @@ probe_tsc_freq(void) (vm_guest == VM_GUEST_NO && CPUID_TO_FAMILY(cpu_id) >= 0x10)) tsc_is_invariant = 1; + if (cpu_feature & CPUID_SSE2) { + tsc_timecounter.tc_get_timecount = + tsc_get_timecount_mfence; + } break; case CPU_VENDOR_INTEL: if ((amd_pminfo & AMDPM_TSC_INVARIANT) != 0 || @@ -271,6 +279,10 @@ probe_tsc_freq(void) (CPUID_TO_FAMILY(cpu_id) == 0xf && CPUID_TO_MODEL(cpu_id) >= 0x3)))) tsc_is_invariant = 1; + if (cpu_feature & CPUID_SSE2) { + tsc_timecounter.tc_get_timecount = + tsc_get_timecount_lfence; + } break; case CPU_VENDOR_CENTAUR: if (vm_guest == VM_GUEST_NO && @@ -278,6 +290,10 @@ probe_tsc_freq(void) CPUID_TO_MODEL(cpu_id) >= 0xf && (rdmsr(0x1203) & 0x100000000ULL) == 0) tsc_is_invariant = 1; + if (cpu_feature & CPUID_SSE2) { + tsc_timecounter.tc_get_timecount = + tsc_get_timecount_lfence; + } break; } @@ -328,16 +344,31 @@ init_TSC(void) #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(); \ +/* + * RDTSC is not a serializing instruction, and does not drain + * instruction stream, so we need to drain the stream before executing + * it. It could be fixed by use of RDTSCP, except the instruction is + * not available everywhere. + * + * Use CPUID for draining in the boot-time SMP constistency test. The + * timecounters use MFENCE for AMD CPUs, and LFENCE for others (Intel + * and VIA) when SSE2 is present, and nothing on older machines which + * also do not issue RDTSC prematurely. There, testing for SSE2 and + * vendor is too cumbersome, and we learn about TSC presence from + * CPUID. + * + * Do not use do_cpuid(), since we do not need CPUID results, which + * have to be written into memory with do_cpuid(). + */ +#define TSC_READ(x) \ +static void \ +tsc_read_##x(void *arg) \ +{ \ + uint32_t *tsc = arg; \ + u_int cpu = PCPU_GET(cpuid); \ + \ + __asm __volatile("cpuid" : : : "eax", "ebx", "ecx", "edx"); \ + tsc[cpu * 3 + x] = rdtsc32(); \ } TSC_READ(0) TSC_READ(1) @@ -487,7 +518,16 @@ init: for (shift = 0; shift < 31 && (tsc_freq >> shift) > max_freq; shift++) ; if (shift > 0) { - tsc_timecounter.tc_get_timecount = tsc_get_timecount_low; + if (cpu_feature & CPUID_SSE2) { + if (cpu_vendor_id == CPU_VENDOR_AMD) { + tsc_timecounter.tc_get_timecount = + tsc_get_timecount_low_mfence; + } else { + tsc_timecounter.tc_get_timecount = + tsc_get_timecount_low_lfence; + } + } else + 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", @@ -599,16 +639,48 @@ tsc_get_timecount(struct timecounter *tc __unused) return (rdtsc32()); } -static u_int +static inline 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"); + : "=a" (rv) : "c" ((int)(intptr_t)tc->tc_priv) : "edx"); return (rv); } +static u_int +tsc_get_timecount_lfence(struct timecounter *tc __unused) +{ + + lfence(); + return (rdtsc32()); +} + +static u_int +tsc_get_timecount_low_lfence(struct timecounter *tc) +{ + + lfence(); + return (tsc_get_timecount_low(tc)); +} + +static u_int +tsc_get_timecount_mfence(struct timecounter *tc __unused) +{ + + mfence(); + return (rdtsc32()); +} + +static u_int +tsc_get_timecount_low_mfence(struct timecounter *tc) +{ + + mfence(); + return (tsc_get_timecount_low(tc)); +} + uint32_t cpu_fill_vdso_timehands(struct vdso_timehands *vdso_th) { |