Messages in this thread Patch in this message | | | Date | Fri, 06 Jun 2008 18:02:40 -0700 | From | Chris Wright <> | Subject | [patch 25/50] x86: fix setup of cyc2ns in tsc_64.c |
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-stable review patch. If anyone has any objections, please let us know. ---------------------
From: Thomas Gleixner <tglx@linutronix.de>
upstream commit: b6db80ee1331e7beaeb91b4b3d946dd16c72e388
When the TSC is calibrated against the PIT due to the nonavailability of PMTIMER/HPET or due to SMI interference then the setup of the per CPU cyc2ns variables is skipped. This is unlikely to happen but it would definitely render sched_clock() unusable.
This was introduced with commit 53d517cdbaac704352b3d0c10fecb99e0b54572e
x86: scale cyc_2_nsec according to CPU frequency
Update the per CPU cyc2ns variables in all exit pathes of tsc_calibrate.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: stable@kernel.org Signed-off-by: Chris Wright <chrisw@sous-sol.org> --- arch/x86/kernel/tsc_64.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-)
--- a/arch/x86/kernel/tsc_64.c +++ b/arch/x86/kernel/tsc_64.c @@ -227,14 +227,14 @@ void __init tsc_calibrate(void) /* hpet or pmtimer available ? */ if (!hpet && !pm1 && !pm2) { printk(KERN_INFO "TSC calibrated against PIT\n"); - return; + goto out; } /* Check, whether the sampling was disturbed by an SMI */ if (tsc1 == ULONG_MAX || tsc2 == ULONG_MAX) { printk(KERN_WARNING "TSC calibration disturbed by SMI, " "using PIT calibration result\n"); - return; + goto out; } tsc2 = (tsc2 - tsc1) * 1000000L; @@ -255,6 +255,7 @@ void __init tsc_calibrate(void) tsc_khz = tsc2 / tsc1; +out: for_each_possible_cpu(cpu) set_cyc2ns_scale(tsc_khz, cpu); } --
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