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Nicholas Piggin authored
Currently powernv reboot and shutdown requests just leave secondaries to do their own things. This is undesirable because they can trigger any number of watchdogs while waiting for reboot, but also we don't know what else they might be doing -- they might be causing trouble, trampling memory, etc. The opal scheduled flash update code already ran into watchdog problems due to flashing taking a long time, and it was fixed with 2196c6f1 ("powerpc/powernv: Return secondary CPUs to firmware before FW update"), which returns secondaries to opal. It's been found that regular reboots can take over 10 seconds, which can result in the hard lockup watchdog firing, reboot: Restarting system [ 360.038896709,5] OPAL: Reboot request... Watchdog CPU:0 Hard LOCKUP Watchdog CPU:44 detected Hard LOCKUP other CPUS:16 Watchdog CPU:16 Hard LOCKUP watchdog: BUG: soft lockup - CPU#16 stuck for 3s! [swapper/16:0] This patch removes the special case for flash update, and calls smp_send_stop in all cases before calling reboot/shutdown. smp_send_stop could return CPUs to OPAL, the main reason not to is that the request could come from a NMI that interrupts OPAL code, so re-entry to OPAL can cause a number of problems. Putting secondaries into simple spin loops improves the chances of a successful reboot. Signed-off-by:
Nicholas Piggin <npiggin@gmail.com> Reviewed-by:
Vasant Hegde <hegdevasant@linux.vnet.ibm.com> Signed-off-by:
Michael Ellerman <mpe@ellerman.id.au>
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