From bd82d4bd21880b7c4d5f5756be435095d6ae07b5 Mon Sep 17 00:00:00 2001 From: Julien Thierry Date: Tue, 11 Jun 2019 10:38:10 +0100 Subject: arm64: Fix incorrect irqflag restore for priority masking When using IRQ priority masking to disable interrupts, in order to deal with the PSR.I state, local_irq_save() would convert the I bit into a PMR value (GIC_PRIO_IRQOFF). This resulted in local_irq_restore() potentially modifying the value of PMR in undesired location due to the state of PSR.I upon flag saving [1]. In an attempt to solve this issue in a less hackish manner, introduce a bit (GIC_PRIO_IGNORE_PMR) for the PMR values that can represent whether PSR.I is being used to disable interrupts, in which case it takes precedence of the status of interrupt masking via PMR. GIC_PRIO_PSR_I_SET is chosen such that ( | GIC_PRIO_PSR_I_SET) does not mask more interrupts than as some sections (e.g. arch_cpu_idle(), interrupt acknowledge path) requires PMR not to mask interrupts that could be signaled to the CPU when using only PSR.I. [1] https://www.spinics.net/lists/arm-kernel/msg716956.html Fixes: 4a503217ce37 ("arm64: irqflags: Use ICC_PMR_EL1 for interrupt masking") Cc: # 5.1.x- Reported-by: Zenghui Yu Cc: Steven Rostedt Cc: Wei Li Cc: Will Deacon Cc: Christoffer Dall Cc: James Morse Cc: Suzuki K Pouloze Cc: Oleg Nesterov Reviewed-by: Marc Zyngier Signed-off-by: Julien Thierry Signed-off-by: Catalin Marinas --- arch/arm64/kernel/process.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'arch/arm64/kernel/process.c') diff --git a/arch/arm64/kernel/process.c b/arch/arm64/kernel/process.c index 3767fb21a5b8..58efc3727778 100644 --- a/arch/arm64/kernel/process.c +++ b/arch/arm64/kernel/process.c @@ -94,7 +94,7 @@ static void __cpu_do_idle_irqprio(void) * be raised. */ pmr = gic_read_pmr(); - gic_write_pmr(GIC_PRIO_IRQON); + gic_write_pmr(GIC_PRIO_IRQON | GIC_PRIO_PSR_I_SET); __cpu_do_idle(); -- cgit v1.2.1