diff options
| author | Nicholas Piggin <npiggin@gmail.com> | 2023-01-21 13:26:18 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2023-03-17 10:50:30 +0300 |
| commit | ac872bb004c3033afef0bfe06d3558744aeca739 (patch) | |
| tree | df3c5cdb266aa7385c4da39eca1e276f555c7955 /arch/powerpc/include/asm | |
| parent | 5759afd5e5844cfe1483273db0e1b590a73eeec0 (diff) | |
| download | linux-ac872bb004c3033afef0bfe06d3558744aeca739.tar.xz | |
powerpc/64: Don't recurse irq replay
[ Upstream commit 5746ca131e2496ccd5bb4d7a0244d6c38070cbf5 ]
Interrupt handlers called by soft-pending irq replay code can run
softirqs, softirq replay enables and disables local irqs, which allows
interrupts to come in including soft-masked interrupts, and it can
cause pending irqs to be replayed again. That makes the soft irq replay
state machine and possible races more complicated and fragile than it
needs to be.
Use irq_enter/irq_exit around irq replay to prevent softirqs running
while interrupts are being replayed. Softirqs will now be run at the
irq_exit() call after all the irq replaying is done. This prevents irqs
being replayed while irqs are being replayed, and should hopefully make
things simpler and easier to think about and debug.
A new PACA_IRQ_REPLAYING is added to prevent asynchronous interrupt
handlers hard-enabling EE while pending irqs are being replayed, because
that causes new pending irqs to arrive which is also a complexity. This
means pending irqs won't be profiled quite so well because perf irqs
can't be taken.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20230121102618.2824429-1-npiggin@gmail.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'arch/powerpc/include/asm')
| -rw-r--r-- | arch/powerpc/include/asm/hw_irq.h | 6 |
1 files changed, 4 insertions, 2 deletions
diff --git a/arch/powerpc/include/asm/hw_irq.h b/arch/powerpc/include/asm/hw_irq.h index eb6d094083fd..317659fdeacf 100644 --- a/arch/powerpc/include/asm/hw_irq.h +++ b/arch/powerpc/include/asm/hw_irq.h @@ -36,15 +36,17 @@ #define PACA_IRQ_DEC 0x08 /* Or FIT */ #define PACA_IRQ_HMI 0x10 #define PACA_IRQ_PMI 0x20 +#define PACA_IRQ_REPLAYING 0x40 /* * Some soft-masked interrupts must be hard masked until they are replayed * (e.g., because the soft-masked handler does not clear the exception). + * Interrupt replay itself must remain hard masked too. */ #ifdef CONFIG_PPC_BOOK3S -#define PACA_IRQ_MUST_HARD_MASK (PACA_IRQ_EE|PACA_IRQ_PMI) +#define PACA_IRQ_MUST_HARD_MASK (PACA_IRQ_EE|PACA_IRQ_PMI|PACA_IRQ_REPLAYING) #else -#define PACA_IRQ_MUST_HARD_MASK (PACA_IRQ_EE) +#define PACA_IRQ_MUST_HARD_MASK (PACA_IRQ_EE|PACA_IRQ_REPLAYING) #endif #endif /* CONFIG_PPC64 */ |