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irqchip/gic-v3: Ensure pseudo-NMIs have an ISB between ack and handling

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[ Upstream commit adf14453d2 ]

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:

  39a06b67c2 ("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:

  f32c926651 ("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: f32c926651 ("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>
This commit is contained in:
Mark Rutland 2022-05-13 14:30:36 +01:00 committed by Greg Kroah-Hartman
parent 51ebf1b6a0
commit b82dfacba5
1 changed files with 3 additions and 0 deletions
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3
drivers/irqchip/irq-gic-v3.c
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@ -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.