From 101a5b665dcdff169ae7ad90556604c483d9027e Mon Sep 17 00:00:00 2001 From: Mark Rutland Date: Mon, 7 Jun 2021 10:46:09 +0100 Subject: arm64: entry: move NMI preempt logic to C Currently portions of our preempt logic are written in C while other parts are written in assembly. Let's clean this up a little bit by moving the NMI preempt checks to C. For now, the preempt count (and need_resched) checking is left in assembly, and will be converted with the body of the IRQ handler in subsequent patches. Other than the increased lockdep coverage there should be no functional change as a result of this patch. Signed-off-by: Mark Rutland Acked-by: Catalin Marinas Acked-by: Marc Zyngier Reviewed-by: Joey Gouly Cc: James Morse Cc: Will Deacon Link: https://lore.kernel.org/r/20210607094624.34689-6-mark.rutland@arm.com Signed-off-by: Will Deacon --- arch/arm64/kernel/entry-common.c | 9 +++++++++ 1 file changed, 9 insertions(+) (limited to 'arch/arm64/kernel/entry-common.c') diff --git a/arch/arm64/kernel/entry-common.c b/arch/arm64/kernel/entry-common.c index 1fe60578e556..08d17eb0ce13 100644 --- a/arch/arm64/kernel/entry-common.c +++ b/arch/arm64/kernel/entry-common.c @@ -121,6 +121,15 @@ asmlinkage void __sched arm64_preempt_schedule_irq(void) { lockdep_assert_irqs_disabled(); + /* + * DAIF.DA are cleared at the start of IRQ/FIQ handling, and when GIC + * priority masking is used the GIC irqchip driver will clear DAIF.IF + * using gic_arch_enable_irqs() for normal IRQs. If anything is set in + * DAIF we must have handled an NMI, so skip preemption. + */ + if (system_uses_irq_prio_masking() && read_sysreg(daif)) + return; + /* * Preempting a task from an IRQ means we leave copies of PSTATE * on the stack. cpufeature's enable calls may modify PSTATE, but -- cgit