Christopher S. Hall f9677e0f83 x86/tsc: Always Running Timer (ART) correlated clocksource ... On modern Intel systems TSC is derived from the new Always Running Timer (ART). ART can be captured simultaneous to the capture of audio and network device clocks, allowing a correlation between timebases to be constructed. Upon capture, the driver converts the captured ART value to the appropriate system clock using the correlated clocksource mechanism. On systems that support ART a new CPUID leaf (0x15) returns parameters “m” and “n” such that: TSC_value = (ART_value * m) / n + k [n >= 1] [k is an offset that can adjusted by a privileged agent. The IA32_TSC_ADJUST MSR is an example of an interface to adjust k. See 17.14.4 of the Intel SDM for more details] Cc: Prarit Bhargava <prarit@redhat.com> Cc: Richard Cochran <richardcochran@gmail.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@kernel.org> Cc: Andy Lutomirski <luto@amacapital.net> Cc: kevin.b.stanton@intel.com Cc: kevin.j.clarke@intel.com Cc: hpa@zytor.com Cc: jeffrey.t.kirsher@intel.com Cc: netdev@vger.kernel.org Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Christopher S. Hall <christopher.s.hall@intel.com> [jstultz: Tweaked to fix build issue, also reworked math for 64bit division on 32bit systems, as well as !CONFIG_CPU_FREQ build fixes] Signed-off-by: John Stultz <john.stultz@linaro.org>		2016-03-03 14:23:34 -08:00
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asm	x86/tsc: Always Running Timer (ART) correlated clocksource	2016-03-03 14:23:34 -08:00
uapi/asm	* s390: Support for runtime instrumentation within guests,	2016-01-12 13:22:12 -08:00