From: Mark Rutland mark.rutland@arm.com
[ 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 mark.rutland@arm.com Cc: Marc Zyngier maz@kernel.org Cc: Thomas Gleixner tglx@linutronix.de Cc: Will Deacon will.deacon@arm.com Signed-off-by: Marc Zyngier maz@kernel.org Link: https://lore.kernel.org/r/20220513133038.226182-2-mark.rutland@arm.com Signed-off-by: Sasha Levin sashal@kernel.org --- 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 907af63d1bba..3e3afb30de50 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.