3.14-stable review patch. If anyone has any objections, please let me know. ------------------ From: Chen Yu <yu.c.chen@xxxxxxxxx> commit 886123fb3a8656699dff40afa0573df359abeb18 upstream. Currently we read the tsc radio: ratio = (MSR_PLATFORM_INFO >> 8) & 0x1f; Thus we get bit 8-12 of MSR_PLATFORM_INFO, however according to the SDM (35.5), the ratio bits are bit 8-15. Ignoring the upper bits can result in an incorrect tsc ratio, which causes the TSC calibration and the Local APIC timer frequency to be incorrect. Fix this problem by masking 0xff instead. [ tglx: Massaged changelog ] Fixes: 7da7c1561366 "x86, tsc: Add static (MSR) TSC calibration on Intel Atom SoCs" Signed-off-by: Chen Yu <yu.c.chen@xxxxxxxxx> Cc: "Rafael J. Wysocki" <rafael@xxxxxxxxxx> Cc: Bin Gao <bin.gao@xxxxxxxxx> Cc: Len Brown <lenb@xxxxxxxxxx> Link: http://lkml.kernel.org/r/1462505619-5516-1-git-send-email-yu.c.chen@xxxxxxxxx Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- arch/x86/kernel/tsc_msr.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/arch/x86/kernel/tsc_msr.c +++ b/arch/x86/kernel/tsc_msr.c @@ -92,7 +92,7 @@ unsigned long try_msr_calibrate_tsc(void if (freq_desc_tables[cpu_index].msr_plat) { rdmsr(MSR_PLATFORM_INFO, lo, hi); - ratio = (lo >> 8) & 0x1f; + ratio = (lo >> 8) & 0xff; } else { rdmsr(MSR_IA32_PERF_STATUS, lo, hi); ratio = (hi >> 8) & 0x1f; -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html