diff options
Diffstat (limited to 'sys/x86')
| -rw-r--r-- | sys/x86/x86/tsc.c | 18 |
1 files changed, 11 insertions, 7 deletions
diff --git a/sys/x86/x86/tsc.c b/sys/x86/x86/tsc.c index 3e0300b..40d5f3c 100644 --- a/sys/x86/x86/tsc.c +++ b/sys/x86/x86/tsc.c @@ -63,6 +63,11 @@ SYSCTL_INT(_kern_timecounter, OID_AUTO, smp_tsc, CTLFLAG_RDTUN, &smp_tsc, 0, 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 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, @@ -84,12 +89,11 @@ init_TSC(void) { u_int64_t tscval[2]; - if (cpu_feature & CPUID_TSC) - tsc_present = 1; - else - tsc_present = 0; + if ((cpu_feature & CPUID_TSC) == 0) + return; + tsc_present = 1; - if (!tsc_present) + if (tsc_disabled) return; if (bootverbose) @@ -151,7 +155,7 @@ void init_TSC_tc(void) { - if (!tsc_present) + if (!tsc_present || tsc_disabled) return; /* @@ -248,7 +252,7 @@ tsc_freq_changed(void *arg, const struct cf_level *level, int status) { /* If there was an error during the transition, don't do anything. */ - if (status != 0) + if (tsc_disabled || status != 0) return; /* Total setting for this level gives the new frequency in MHz. */ |
