Messages in this thread Patch in this message | | | From | Qi Zheng <> | Subject | [PATCH v2] arm64: run softirqs on the per-CPU IRQ stack | Date | Tue, 2 Aug 2022 14:53:25 +0800 |
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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> --- 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 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 1652a9800ebe..90f1ab403724 100644 --- a/arch/arm64/Kconfig +++ b/arch/arm64/Kconfig @@ -226,6 +226,7 @@ config ARM64 select THREAD_INFO_IN_TASK select HAVE_ARCH_USERFAULTFD_MINOR if USERFAULTFD select TRACE_IRQFLAGS_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"); -- 2.20.1
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