Messages in this thread | | | From | Max Filippov <> | Date | Tue, 14 Feb 2023 11:48:41 -0800 | Subject | Re: [PATCH v2 19/24] xtensa/cpu: Make sure cpu_die() doesn't return |
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On Tue, Feb 14, 2023 at 10:23 AM Josh Poimboeuf <jpoimboe@kernel.org> wrote: > On Tue, Feb 14, 2023 at 08:55:32AM +0100, Philippe Mathieu-Daudé wrote: > > Can you update the documentation along? Currently we have: > > > > /* > > * Called from the idle thread for the CPU which has been shutdown. > > * > > * Note that we disable IRQs here, but do not re-enable them > > * before returning to the caller. This is also the behaviour > > * of the other hotplug-cpu capable cores, so presumably coming > > * out of idle fixes this. > > */ > > void __ref cpu_die(void) > { > idle_task_exit(); > local_irq_disable(); > __asm__ __volatile__( > " movi a2, cpu_restart\n" > " jx a2\n"); > > BUG(); > } > > Hm, not only is the comment wrong, but it seems to be branching to > cpu_restart? That doesn't seem right at all.
Perhaps the name is a bit misleading. The CPU that enters 'cpu_restart' loops there until a call to 'boot_secondary' releases it, after which it goes to '_startup'. So it is a restart, but not immediate.
-- Thanks. -- Max
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