[PW_SID:1053521] irqchip/sifive-plic: Fix frozen interrupt due to affinity setting#1469
[PW_SID:1053521] irqchip/sifive-plic: Fix frozen interrupt due to affinity setting#1469linux-riscv-bot wants to merge 1 commit intoworkflow__riscv__fixesfrom
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PLIC ignores interrupt completion message for disabled interrupt, explained
by the specification:
The PLIC signals it has completed executing an interrupt handler by
writing the interrupt ID it received from the claim to the
claim/complete register. The PLIC does not check whether the completion
ID is the same as the last claim ID for that target. If the completion
ID does not match an interrupt source that is currently enabled for
the target, the completion is silently ignored.
This caused problem in the past, because an interrupt can be disabled while
still being handled and plic_irq_eoi() had no effect. That was fixed by
checking if the interrupt is disabled, and if so enable it, before sending
the completion message. That check is done with irqd_irq_disabled().
However, that is not sufficient because the enable bit for the handling
hart can be zero despite irqd_irq_disabled(d) being false. This can happen
when affinity setting is changed while a hart is still handling the
interrupt.
This problem is easily reproducible by dumping a large file to uart (which
generates lots of interrupts) and at the same time keep changing the uart
interrupt's affinity setting. The uart port becomes frozen almost
jnstantly.
Fix by checking PLIC's enable bit instead of irqd_irq_disabled().
Fixes: cc9f04f ("irqchip/sifive-plic: Implement irq_set_affinity() for SMP host")
Signed-off-by: Nam Cao <namcao@linutronix.de>
Signed-off-by: Linux RISC-V bot <linux.riscv.bot@gmail.com>
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Patch 1: "irqchip/sifive-plic: Fix frozen interrupt due to affinity setting" |
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Patch 1: "irqchip/sifive-plic: Fix frozen interrupt due to affinity setting" |
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Patch 1: "irqchip/sifive-plic: Fix frozen interrupt due to affinity setting" |
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Patch 1: "irqchip/sifive-plic: Fix frozen interrupt due to affinity setting" |
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Patch 1: "irqchip/sifive-plic: Fix frozen interrupt due to affinity setting" |
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Patch 1: "irqchip/sifive-plic: Fix frozen interrupt due to affinity setting" |
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Patch 1: "irqchip/sifive-plic: Fix frozen interrupt due to affinity setting" |
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Patch 1: "irqchip/sifive-plic: Fix frozen interrupt due to affinity setting" |
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Patch 1: "irqchip/sifive-plic: Fix frozen interrupt due to affinity setting" |
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Patch 1: "irqchip/sifive-plic: Fix frozen interrupt due to affinity setting" |
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Patch 1: "irqchip/sifive-plic: Fix frozen interrupt due to affinity setting" |
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Patch 1: "irqchip/sifive-plic: Fix frozen interrupt due to affinity setting" |
2 participants
PR for series 1053521 applied to workflow__riscv__fixes
Name: irqchip/sifive-plic: Fix frozen interrupt due to affinity setting
URL: https://patchwork.kernel.org/project/linux-riscv/list/?series=1053521
Version: 1