x86/tsc: Provide 'tsc=unstable' boot parameter
authorPeter Zijlstra <peterz@infradead.org>
Thu, 13 Apr 2017 12:56:44 +0000 (14:56 +0200)
committerIngo Molnar <mingo@kernel.org>
Mon, 15 May 2017 08:15:14 +0000 (10:15 +0200)
commit8309f86cd41e8714526867177facf7a316d9be53
treeea2ca294166540ec796bfcdb8c3936aabfd61fa9
parent625ed2bf049d5a352c1bcca962d6e133454eaaff
x86/tsc: Provide 'tsc=unstable' boot parameter

Since the clocksource watchdog will only detect broken TSC after the
fact, all TSC based clocks will likely have observed non-continuous
values before/when switching away from TSC.

Therefore only thing to fully avoid random clock movement when your
BIOS randomly mucks with TSC values from SMI handlers is reporting the
TSC as unstable at boot.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
arch/x86/kernel/tsc.c