1 Commits

Author	SHA1	Message	Date
Anton Blanchard	c54b2bf1b5	powerpc: Add ppc64 hard lockup detector support ... The hard lockup detector uses a PMU event as a periodic NMI to detect if we are stuck (where stuck means no timer interrupts have occurred). Ben's rework of the ppc64 soft disable code has made ppc64 PMU exceptions a partial NMI. They can get disabled if an external interrupt comes in, but otherwise PMU interrupts will fire in interrupt disabled regions. We disable the hard lockup detector by default for a few reasons: - It breaks userspace event based branches on POWER8. - It is likely to produce false positives on KVM guests. - Since PMCs can only count to 2^31, counting cycles means we might take multiple PMU exceptions per second per hardware thread even if our hard lockup timeout is 10 seconds. It can be enabled via a boot option, or via procfs. Signed-off-by: Anton Blanchard <anton@samba.org> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>	2015-04-11 20:49:27 +10:00