x86: fix setup of cyc2ns in tsc_64.c

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>

diff --git a/arch/x86/kernel/tsc_64.c b/arch/x86/kernel/tsc_64.c
index d3bebaaad842da20ce9165083825b482333ad088..5153afca671c6980085056e809216cdd4ec9c982 100644 (file)
--- 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);
 }