From 8eb858c44b98e0326bb32fca34ae671995cd73bb Mon Sep 17 00:00:00 2001 From: Qi Zheng Date: Mon, 15 Aug 2022 20:47:39 +0800 Subject: [PATCH] arm64: run softirqs on the per-CPU IRQ stack 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 Reviewed-by: Arnd Bergmann Acked-by: Will Deacon Link: https://lore.kernel.org/r/20220815124739.15948-1-zhengqi.arch@bytedance.com Signed-off-by: Catalin Marinas --- arch/arm64/Kconfig | 1 + arch/arm64/kernel/irq.c | 14 ++++++++++++++ 2 files changed, 15 insertions(+) diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig index b17d6861a3ad..6f1ecf4538f7 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..38dbd3828f13 100644 --- a/arch/arm64/kernel/irq.c +++ b/arch/arm64/kernel/irq.c @@ -21,7 +21,9 @@ #include #include #include +#include #include +#include /* Only access this in an NMI enter/exit */ DEFINE_PER_CPU(struct nmi_ctx, nmi_contexts); @@ -71,6 +73,18 @@ 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"); -- 2.11.0