From 4be1b29795d692d512bb67b770665d6f8ea5cb0b Mon Sep 17 00:00:00 2001 From: Cyril Bur Date: Thu, 12 Feb 2015 15:01:28 -0800 Subject: [PATCH] powerpc: add running_clock for powerpc to prevent spurious softlockup warnings On POWER8 virtualised kernels the VTB register can be read to have a view of time that only increases while the guest is running. This will prevent guests from seeing time jump if a guest is paused for significant amounts of time. On POWER7 and below virtualised kernels stolen time is subtracted from local_clock as a best effort approximation. This will not eliminate spurious warnings in the case of a suspended guest but may reduce the occurance in the case of softlockups due to host over commit. Bare metal kernels should avoid reading the VTB as KVM does not restore sane values when not executing, the approxmation is fine as host kernels won't observe any stolen time. [akpm@linux-foundation.org: coding-style fixes] Signed-off-by: Cyril Bur Cc: Michael Ellerman Cc: Andrew Jones Acked-by: Don Zickus Cc: Ingo Molnar Cc: Ulrich Obergfell Cc: chai wen Cc: Fabian Frederick Cc: Aaron Tomlin Cc: Ben Zhang Cc: Martin Schwidefsky Cc: John Stultz Cc: Thomas Gleixner Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- Reading git-format-patch failed