From 17ce302f3117e9518395847a3120c8a108b587b8 Mon Sep 17 00:00:00 2001 From: Julien Thierry Date: Tue, 11 Jun 2019 10:38:09 +0100 Subject: arm64: Fix interrupt tracing in the presence of NMIs In the presence of any form of instrumentation, nmi_enter() should be done before calling any traceable code and any instrumentation code. Currently, nmi_enter() is done in handle_domain_nmi(), which is much too late as instrumentation code might get called before. Move the nmi_enter/exit() calls to the arch IRQ vector handler. On arm64, it is not possible to know if the IRQ vector handler was called because of an NMI before acknowledging the interrupt. However, It is possible to know whether normal interrupts could be taken in the interrupted context (i.e. if taking an NMI in that context could introduce a potential race condition). When interrupting a context with IRQs disabled, call nmi_enter() as soon as possible. In contexts with IRQs enabled, defer this to the interrupt controller, which is in a better position to know if an interrupt taken is an NMI. Fixes: bc3c03ccb464 ("arm64: Enable the support of pseudo-NMIs") Cc: # 5.1.x- Cc: Will Deacon Cc: Thomas Gleixner Cc: Jason Cooper Cc: Mark Rutland Reviewed-by: Marc Zyngier Signed-off-by: Julien Thierry Signed-off-by: Catalin Marinas --- drivers/irqchip/irq-gic-v3.c | 7 +++++++ 1 file changed, 7 insertions(+) (limited to 'drivers') diff --git a/drivers/irqchip/irq-gic-v3.c b/drivers/irqchip/irq-gic-v3.c index f44cd89cfc40..b176700bb387 100644 --- a/drivers/irqchip/irq-gic-v3.c +++ b/drivers/irqchip/irq-gic-v3.c @@ -472,8 +472,12 @@ static void gic_deactivate_unhandled(u32 irqnr) static inline void gic_handle_nmi(u32 irqnr, struct pt_regs *regs) { + bool irqs_enabled = interrupts_enabled(regs); int err; + if (irqs_enabled) + nmi_enter(); + if (static_branch_likely(&supports_deactivate_key)) gic_write_eoir(irqnr); /* @@ -485,6 +489,9 @@ static inline void gic_handle_nmi(u32 irqnr, struct pt_regs *regs) err = handle_domain_nmi(gic_data.domain, irqnr, regs); if (err) gic_deactivate_unhandled(irqnr); + + if (irqs_enabled) + nmi_exit(); } static asmlinkage void __exception_irq_entry gic_handle_irq(struct pt_regs *regs) -- cgit v1.2.3