x86, AMD: Set ARAT feature on AMD processors
authorBoris Ostrovsky <boris.ostrovsky@amd.com>
Tue, 15 Mar 2011 16:13:44 +0000 (12:13 -0400)
committerIngo Molnar <mingo@elte.hu>
Wed, 16 Mar 2011 13:03:33 +0000 (14:03 +0100)
commitb87cf80af3ba4b4c008b4face3c68d604e1715c6
treede37fabdc7bc8dc73828469ef989a2cf976d8027
parent1d3e09a304e6c4e004ca06356578b171e8735d3c
x86, AMD: Set ARAT feature on AMD processors

Support for Always Running APIC timer (ARAT) was introduced in
commit db954b5898dd3ef3ef93f4144158ea8f97deb058. This feature
allows us to avoid switching timers from LAPIC to something else
(e.g. HPET) and go into timer broadcasts when entering deep
C-states.

AMD processors don't provide a CPUID bit for that feature but
they also keep APIC timers running in deep C-states (except for
cases when the processor is affected by erratum 400). Therefore
we should set ARAT feature bit on AMD CPUs.

Tested-by: Borislav Petkov <borislav.petkov@amd.com>
Acked-by: Andreas Herrmann <andreas.herrmann3@amd.com>
Acked-by: Mark Langsdorf <mark.langsdorf@amd.com>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Boris Ostrovsky <boris.ostrovsky@amd.com>
LKML-Reference: <1300205624-4813-1-git-send-email-ostr@amd64.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
arch/x86/kernel/cpu/amd.c