From: Max Filippov <jcmvbkbc@gmail.com>
To: Josh Poimboeuf <jpoimboe@kernel.org>
Cc: "Philippe Mathieu-Daudé" <philmd@linaro.org>,
linux-kernel@vger.kernel.org, jgross@suse.com,
richard.henderson@linaro.org, ink@jurassic.park.msu.ru,
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chenhuacai@kernel.org, kernel@xen0n.name,
loongarch@lists.linux.dev, f.fainelli@gmail.com,
bcm-kernel-feedback-list@broadcom.com, tsbogend@alpha.franken.de,
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mpe@ellerman.id.au, npiggin@gmail.com,
christophe.leroy@csgroup.eu, linuxppc-dev@lists.ozlabs.org,
ysato@users.sourceforge.jp, dalias@libc.org,
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hpa@zytor.com, chris@zankel.net, linux-xtensa@linux-xtensa.org,
peterz@infradead.org, juri.lelli@redhat.com,
vincent.guittot@linaro.org, dietmar.eggemann@arm.com,
rostedt@goodmis.org, bsegall@google.com, mgorman@suse.de,
bristot@redhat.com, vschneid@redhat.com, paulmck@kernel.org
Subject: Re: [PATCH v2 19/24] xtensa/cpu: Make sure cpu_die() doesn't return
Date: Tue, 14 Feb 2023 11:48:41 -0800 [thread overview]
Message-ID: <CAMo8BfLzV0Oe_i-QrMzE-BE028s6GNvOd827N5+tteELidjpvA@mail.gmail.com> (raw)
In-Reply-To: <20230214182322.r5tyeowxzloiuh72@treble>
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
next prev parent reply other threads:[~2023-02-14 19:48 UTC|newest]
Thread overview: 58+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-02-14 7:05 [PATCH v2 00/24] cpu,sched: Mark arch_cpu_idle_dead() __noreturn Josh Poimboeuf
2023-02-14 7:05 ` [PATCH v2 01/24] alpha/cpu: Expose arch_cpu_idle_dead()'s prototype declaration Josh Poimboeuf
2023-02-14 7:05 ` [PATCH v2 02/24] alpha/cpu: Make sure arch_cpu_idle_dead() doesn't return Josh Poimboeuf
2023-02-14 7:05 ` [PATCH v2 03/24] arm/cpu: " Josh Poimboeuf
2023-02-14 11:15 ` Russell King (Oracle)
2023-02-14 18:39 ` Josh Poimboeuf
2023-02-14 22:01 ` Russell King (Oracle)
2023-02-16 18:38 ` [PATCH v2.1 03/24] arm/cpu: Add unreachable() to arch_cpu_idle_dead() Josh Poimboeuf
2023-02-14 7:05 ` [PATCH v2 04/24] arm64/cpu: Mark cpu_die() __noreturn Josh Poimboeuf
2023-02-14 8:13 ` Philippe Mathieu-Daudé
2023-02-15 13:09 ` Mark Rutland
2023-02-15 19:45 ` Josh Poimboeuf
2023-02-16 18:41 ` [PATCH v2.1 " Josh Poimboeuf
2023-03-02 10:55 ` Philippe Mathieu-Daudé
2023-02-14 7:05 ` [PATCH v2 05/24] csky/cpu: Make sure arch_cpu_idle_dead() doesn't return Josh Poimboeuf
2023-02-14 7:05 ` [PATCH v2 06/24] ia64/cpu: Mark play_dead() __noreturn Josh Poimboeuf
2023-02-14 8:07 ` Philippe Mathieu-Daudé
2023-02-14 7:05 ` [PATCH v2 07/24] loongarch/cpu: Make sure play_dead() doesn't return Josh Poimboeuf
2023-02-14 7:05 ` [PATCH v2 08/24] loongarch/cpu: Mark play_dead() __noreturn Josh Poimboeuf
2023-02-14 8:06 ` Philippe Mathieu-Daudé
2023-02-14 7:05 ` [PATCH v2 09/24] mips/cpu: Expose play_dead()'s prototype definition Josh Poimboeuf
2023-02-14 7:46 ` Philippe Mathieu-Daudé
2023-02-14 18:11 ` Josh Poimboeuf
2023-02-15 8:29 ` Philippe Mathieu-Daudé
2023-02-16 18:42 ` [PATCH v2.1 " Josh Poimboeuf
2023-03-01 18:16 ` Josh Poimboeuf
2023-03-02 10:54 ` Philippe Mathieu-Daudé
2023-02-14 7:05 ` [PATCH v2 10/24] mips/cpu: Make sure play_dead() doesn't return Josh Poimboeuf
2023-02-14 7:50 ` Philippe Mathieu-Daudé
2023-02-14 7:05 ` [PATCH v2 11/24] mips/cpu: Mark play_dead() __noreturn Josh Poimboeuf
2023-02-14 7:50 ` Philippe Mathieu-Daudé
2023-02-14 7:05 ` [PATCH v2 12/24] powerpc/cpu: Mark start_secondary_resume() __noreturn Josh Poimboeuf
2023-02-14 7:19 ` Christophe Leroy
2023-02-14 7:05 ` [PATCH v2 13/24] sh/cpu: Make sure play_dead() doesn't return Josh Poimboeuf
2023-02-14 7:57 ` Philippe Mathieu-Daudé
2023-02-14 18:28 ` Josh Poimboeuf
2023-02-14 7:05 ` [PATCH v2 14/24] sh/cpu: Mark play_dead() __noreturn Josh Poimboeuf
2023-02-14 7:05 ` [PATCH v2 15/24] sh/cpu: Expose arch_cpu_idle_dead()'s prototype definition Josh Poimboeuf
2023-02-14 7:05 ` [PATCH v2 16/24] sparc/cpu: Mark cpu_play_dead() __noreturn Josh Poimboeuf
2023-02-14 7:52 ` Philippe Mathieu-Daudé
2023-02-14 7:05 ` [PATCH v2 17/24] x86/cpu: Make sure play_dead() doesn't return Josh Poimboeuf
2023-02-14 8:05 ` Philippe Mathieu-Daudé
2023-02-14 7:05 ` [PATCH v2 18/24] x86/cpu: Mark play_dead() __noreturn Josh Poimboeuf
2023-02-14 7:05 ` [PATCH v2 19/24] xtensa/cpu: Make sure cpu_die() doesn't return Josh Poimboeuf
2023-02-14 7:55 ` Philippe Mathieu-Daudé
2023-02-14 18:23 ` Josh Poimboeuf
2023-02-14 19:29 ` Steven Rostedt
2023-02-14 19:48 ` Max Filippov [this message]
2023-02-14 20:19 ` Josh Poimboeuf
2023-02-14 7:05 ` [PATCH v2 20/24] xtensa/cpu: Mark cpu_die() __noreturn Josh Poimboeuf
2023-02-14 12:47 ` Max Filippov
2023-02-14 7:05 ` [PATCH v2 21/24] sched/idle: Make sure weak version of arch_cpu_idle_dead() doesn't return Josh Poimboeuf
2023-02-14 7:05 ` [PATCH v2 22/24] objtool: Include weak functions in 'global_noreturns' check Josh Poimboeuf
2023-02-14 7:05 ` [PATCH v2 23/24] init: Make arch_call_rest_init() and rest_init() __noreturn Josh Poimboeuf
2023-02-14 7:05 ` [PATCH v2 24/24] sched/idle: Mark arch_cpu_idle_dead() __noreturn Josh Poimboeuf
2023-02-14 9:25 ` [PATCH v2 00/24] cpu,sched: " Philippe Mathieu-Daudé
2023-02-14 18:29 ` Josh Poimboeuf
2023-02-15 22:22 ` Paul E. McKenney
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