From: Qi Zheng <zhengqi.arch@xxxxxxxxxxxxx> [ Upstream commit 8eb858c44b98e0326bb32fca34ae671995cd73bb ] 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@xxxxxxxxxxxxx> Reviewed-by: Arnd Bergmann <arnd@xxxxxxxx> Acked-by: Will Deacon <will@xxxxxxxxxx> Link: https://lore.kernel.org/r/20220815124739.15948-1-zhengqi.arch@xxxxxxxxxxxxx Signed-off-by: Catalin Marinas <catalin.marinas@xxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> --- 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 24cce3b9ff1a..496c68aa1b98 100644 --- a/arch/arm64/Kconfig +++ b/arch/arm64/Kconfig @@ -221,6 +221,7 @@ 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 <linux/seq_file.h> #include <linux/vmalloc.h> #include <asm/daifflags.h> +#include <asm/exception.h> #include <asm/vmap_stack.h> +#include <asm/softirq_stack.h> /* 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"); -- 2.35.1
