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| author | Ingo Molnar <mingo@elte.hu> | 2008-06-25 12:30:54 +0200 |
|---|---|---|
| committer | Ingo Molnar <mingo@elte.hu> | 2008-06-25 12:30:54 +0200 |
| commit | 0ed368c71aa65cba8d349432bd4dab4a9a2eb39c (patch) | |
| tree | 7746534bafd57f6764bda8f26efc3929a4acf914 /arch/x86/kernel/tsc_32.c | |
| parent | 7aaaec38fcd9ef3172e69f8c19f20113830a8498 (diff) | |
| parent | 543cf4cb3fe6f6cae3651ba918b9c56200b257d0 (diff) | |
Merge branch 'linus' into x86/kconfigtip-x86-kconfig-2008-06-25_10.30_Wed
Diffstat (limited to 'arch/x86/kernel/tsc_32.c')
| -rw-r--r-- | arch/x86/kernel/tsc_32.c | 18 |
1 files changed, 8 insertions, 10 deletions
diff --git a/arch/x86/kernel/tsc_32.c b/arch/x86/kernel/tsc_32.c index 068759db63dd..65b70637ad97 100644 --- a/arch/x86/kernel/tsc_32.c +++ b/arch/x86/kernel/tsc_32.c @@ -14,7 +14,10 @@ #include "mach_timer.h" -static int tsc_disabled; +/* native_sched_clock() is called before tsc_init(), so + we must start with the TSC soft disabled to prevent + erroneous rdtsc usage on !cpu_has_tsc processors */ +static int tsc_disabled = -1; /* * On some systems the TSC frequency does not @@ -402,25 +405,20 @@ void __init tsc_init(void) { int cpu; - if (!cpu_has_tsc || tsc_disabled) { - /* Disable the TSC in case of !cpu_has_tsc */ - tsc_disabled = 1; + if (!cpu_has_tsc || tsc_disabled > 0) return; - } cpu_khz = calculate_cpu_khz(); tsc_khz = cpu_khz; if (!cpu_khz) { mark_tsc_unstable("could not calculate TSC khz"); - /* - * We need to disable the TSC completely in this case - * to prevent sched_clock() from using it. - */ - tsc_disabled = 1; return; } + /* now allow native_sched_clock() to use rdtsc */ + tsc_disabled = 0; + printk("Detected %lu.%03lu MHz processor.\n", (unsigned long)cpu_khz / 1000, (unsigned long)cpu_khz % 1000); |