Re: [PATCH v2 03/14] arm: arm64: Don't use disable_nonboot_cpus()

Qais Yousef
2020-01-21T16:50:36Z

On 11/25/19 11:27, Qais Yousef wrote:
> disable_nonboot_cpus() is not safe to use when doing machine_down(),
> because it relies on freeze_secondary_cpus() which in return is
> a suspend/resume related freeze and could abort if the logic detects any
> pending activities that can prevent finishing the offlining process.
>
> Beside disable_nonboot_cpus() is dependent on CONFIG_PM_SLEEP_SMP which
> is an othogonal config to rely on to ensure this function works
> correctly.
>
> Signed-off-by: Qais Yousef <qais.yousef@arm.com>
> CC: Russell King <linux@armlinux.org.uk>
> CC: Catalin Marinas <catalin.marinas@arm.com>
> CC: Will Deacon <will@kernel.org>
> CC: linux-arm-kernel@lists.infradead.org
> CC: linux-kernel@vger.kernel.org
> ---

Ping :)

I'm missing ACKs on this patch and patch 4 for arm64. Hopefully none should be
controversial.

Thanks!

--
Qais Yousef

> arch/arm/kernel/reboot.c | 4 ++--
> arch/arm64/kernel/process.c | 4 ++--
> 2 files changed, 4 insertions(+), 4 deletions(-)
>
> diff --git a/arch/arm/kernel/reboot.c b/arch/arm/kernel/reboot.c
> index bb18ed0539f4..58ad1a70f770 100644
> --- a/arch/arm/kernel/reboot.c
> +++ b/arch/arm/kernel/reboot.c
> @@ -88,11 +88,11 @@ void soft_restart(unsigned long addr)
> * to execute e.g. a RAM-based pin loop is not sufficient. This allows the
> * kexec'd kernel to use any and all RAM as it sees fit, without having to
> * avoid any code or data used by any SW CPU pin loop. The CPU hotplug
> - * functionality embodied in disable_nonboot_cpus() to achieve this.
> + * functionality embodied in smp_shutdown_nonboot_cpus() to achieve this.
> */
> void machine_shutdown(void)
> {
> - disable_nonboot_cpus();
> + smp_shutdown_nonboot_cpus(0);
> }
>
> /*
> diff --git a/arch/arm64/kernel/process.c b/arch/arm64/kernel/process.c
> index 71f788cd2b18..3bcc9bfc581e 100644
> --- a/arch/arm64/kernel/process.c
> +++ b/arch/arm64/kernel/process.c
> @@ -141,11 +141,11 @@ void arch_cpu_idle_dead(void)
> * to execute e.g. a RAM-based pin loop is not sufficient. This allows the
> * kexec'd kernel to use any and all RAM as it sees fit, without having to
> * avoid any code or data used by any SW CPU pin loop. The CPU hotplug
> - * functionality embodied in disable_nonboot_cpus() to achieve this.
> + * functionality embodied in smpt_shutdown_nonboot_cpus() to achieve this.
> */
> void machine_shutdown(void)
> {
> - disable_nonboot_cpus();
> + smp_shutdown_nonboot_cpus(0);
> }
>
> /*
> --
> 2.17.1
>