From: Qi Zheng <zhengqi.arch@bytedance.com>
To: will@kernel.org
Cc: linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org, Arnd Bergmann <arnd@arndb.de>,
Catalin Marinas <catalin.marinas@arm.com>,
Mark Rutland <mark.rutland@arm.com>
Subject: Re: [PATCH v3] arm64: run softirqs on the per-CPU IRQ stack
Date: Fri, 26 Aug 2022 12:16:04 +0800 [thread overview]
Message-ID: <595c912a-1503-d420-f32f-297b824decae@bytedance.com> (raw)
In-Reply-To: <20220815124739.15948-1-zhengqi.arch@bytedance.com>
On 2022/8/15 20:47, Qi Zheng wrote:
> Currently arm64 supports per-CPU IRQ stack, but softirqs
> are still handled in the task context.
>
> Since any call to local_bh_enable() at any level in the task's
> call stack may trigger a softirq processing run, which could
> potentially cause a task stack overflow if the combined stack
> footprints exceed the stack's size, let's run these softirqs
> on the IRQ stack as well.
>
> Signed-off-by: Qi Zheng <zhengqi.arch@bytedance.com>
> Reviewed-by: Arnd Bergmann <arnd@arndb.de>
> Acked-by: Will Deacon <will@kernel.org>
> ---
> v2: https://lore.kernel.org/lkml/20220802065325.39740-1-zhengqi.arch@bytedance.com/
> v1: https://lore.kernel.org/lkml/20220708094950.41944-1-zhengqi.arch@bytedance.com/
> RFC: https://lore.kernel.org/lkml/20220707110511.52129-1-zhengqi.arch@bytedance.com/
>
> Changelog in v2 -> v3:
> - rebase onto the v6.0-rc1
Gentle ping.
Thanks,
Qi
>
> Changelog in v1 -> v2:
> - temporarily discard [PATCH v1 2/2] to allow this patch to be merged first
> - rebase onto the v5.19
> - collect Reviewed-by and Acked-by
>
> Changelog in RFC -> v1:
> - fix conflicts with commit f2c5092190f2 ("arch/*: Disable softirq stacks on PREEMPT_RT.")
>
> arch/arm64/Kconfig | 1 +
> arch/arm64/kernel/irq.c | 13 +++++++++++++
> 2 files changed, 14 insertions(+)
>
> diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
> index 571cc234d0b3..ee92f5887cf6 100644
> --- a/arch/arm64/Kconfig
> +++ b/arch/arm64/Kconfig
> @@ -230,6 +230,7 @@ config ARM64
> select HAVE_ARCH_USERFAULTFD_MINOR if USERFAULTFD
> select TRACE_IRQFLAGS_SUPPORT
> select TRACE_IRQFLAGS_NMI_SUPPORT
> + select HAVE_SOFTIRQ_ON_OWN_STACK
> help
> ARM 64-bit (AArch64) Linux support.
>
> diff --git a/arch/arm64/kernel/irq.c b/arch/arm64/kernel/irq.c
> index bda49430c9ea..c36ad20a52f3 100644
> --- a/arch/arm64/kernel/irq.c
> +++ b/arch/arm64/kernel/irq.c
> @@ -22,6 +22,7 @@
> #include <linux/vmalloc.h>
> #include <asm/daifflags.h>
> #include <asm/vmap_stack.h>
> +#include <asm/exception.h>
>
> /* Only access this in an NMI enter/exit */
> DEFINE_PER_CPU(struct nmi_ctx, nmi_contexts);
> @@ -71,6 +72,18 @@ static void init_irq_stacks(void)
> }
> #endif
>
> +#ifndef CONFIG_PREEMPT_RT
> +static void ____do_softirq(struct pt_regs *regs)
> +{
> + __do_softirq();
> +}
> +
> +void do_softirq_own_stack(void)
> +{
> + call_on_irq_stack(NULL, ____do_softirq);
> +}
> +#endif
> +
> static void default_handle_irq(struct pt_regs *regs)
> {
> panic("IRQ taken without a root IRQ handler\n");
--
Thanks,
Qi
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next prev parent reply other threads:[~2022-08-26 4:17 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-08-15 12:47 [PATCH v3] arm64: run softirqs on the per-CPU IRQ stack Qi Zheng
2022-08-26 4:16 ` Qi Zheng [this message]
2022-09-07 7:04 ` Qi Zheng
2022-09-07 13:34 ` Will Deacon
2022-09-07 14:50 ` Qi Zheng
2022-09-08 18:34 ` Catalin Marinas
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