From b82dfacba5762da1c697a180d579624fc85a5e15 Mon Sep 17 00:00:00 2001 From: Mark Rutland Date: Fri, 13 May 2022 14:30:36 +0100 Subject: [PATCH] irqchip/gic-v3: Ensure pseudo-NMIs have an ISB between ack and handling [ Upstream commit adf14453d2c037ab529040c1186ea32e277e783a ] There are cases where a context synchronization event is necessary between an IRQ being raised and being handled, and there are races such that we cannot rely upon the exception entry being subsequent to the interrupt being raised. We identified and fixes this for regular IRQs in commit: 39a06b67c2c1256b ("irqchip/gic: Ensure we have an ISB between ack and ->handle_irq") Unfortunately, we forgot to do the same for psuedo-NMIs when support for those was added in commit: f32c926651dcd168 ("irqchip/gic-v3: Handle pseudo-NMIs") Which means that when pseudo-NMIs are used for PMU support, we'll hit the same problem. Apply the same fix as for regular IRQs. Note that when EOI mode 1 is in use, the call to gic_write_eoir() will provide an ISB. Fixes: f32c926651dcd168 ("irqchip/gic-v3: Handle pseudo-NMIs") Signed-off-by: Mark Rutland Cc: Marc Zyngier Cc: Thomas Gleixner Cc: Will Deacon Signed-off-by: Marc Zyngier Link: https://lore.kernel.org/r/20220513133038.226182-2-mark.rutland@arm.com Signed-off-by: Sasha Levin --- drivers/irqchip/irq-gic-v3.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/drivers/irqchip/irq-gic-v3.c b/drivers/irqchip/irq-gic-v3.c index fd4fb1b..d8ea330 100644 --- a/drivers/irqchip/irq-gic-v3.c +++ b/drivers/irqchip/irq-gic-v3.c @@ -654,6 +654,9 @@ static inline void gic_handle_nmi(u32 irqnr, struct pt_regs *regs) if (static_branch_likely(&supports_deactivate_key)) gic_write_eoir(irqnr); + else + isb() + /* * Leave the PSR.I bit set to prevent other NMIs to be * received while handling this one. -- 2.7.4