From: Mark Brown <broonie@kernel.org> Our goal with superpriority interrupts is to use them as NMIs, taking advantage of the much smaller regions where they are masked to allow prompt handling of the most time critical interrupts. When an interrupt configured with superpriority we will enter EL1 as normal for any interrupt, the presence of a superpriority interrupt is indicated with a status bit in ISR_EL1. We use this to check for the presence of a superpriority interrupt before we unmask anything in elX_interrupt(), reporting without unmasking any interrupts. If no superpriority interrupt is present then we handle normal interrupts as normal, superpriority interrupts will be unmasked while doing so as a result of setting DAIF_PROCCTX. Both IRQs and FIQs may be configured with superpriority so we handle both, passing an additional root handler into the elX_interrupt() function along with the mask for the bit in ISR_EL1 which indicates the presence of the relevant kind of superpriority interrupt. These root handlers can be configured by the interrupt controller similarly to the root handlers for normal interrupts using the newly added set_handle_nmi_irq() and set_handle_nmi_fiq() functions. Signed-off-by: Mark Brown <broonie@kernel.org> Signed-off-by: Jie Liu <liujie375@h-partners.com> --- arch/arm64/include/asm/sysreg.h | 2 ++ drivers/irqchip/irq-gic-v3.c | 30 ++++++++++++++++++++++++++++++ 2 files changed, 32 insertions(+) diff --git a/arch/arm64/include/asm/sysreg.h b/arch/arm64/include/asm/sysreg.h index 521f2c6cce86..761b26417a5d 100644 --- a/arch/arm64/include/asm/sysreg.h +++ b/arch/arm64/include/asm/sysreg.h @@ -205,6 +205,7 @@ #define SYS_ALLINT sys_reg(3, 0, 4, 3, 0) #define SYS_ICC_PMR_EL1 sys_reg(3, 0, 4, 6, 0) +#define SYS_ICC_NMIAR1_EL1 sys_reg(3, 0, 12, 9, 5) #define SYS_AFSR0_EL1 sys_reg(3, 0, 5, 1, 0) #define SYS_AFSR1_EL1 sys_reg(3, 0, 5, 1, 1) @@ -229,6 +230,7 @@ #define HCRX_EL2_TALLINT BIT(6) #define HCRX_EL2_TALLINT_MASK GENMASK(6, 6) #define ALLINT_ALLINT BIT(13) +#define ISR_EL1_IS BIT(10) /*** Statistical Profiling Extension ***/ /* ID registers */ diff --git a/drivers/irqchip/irq-gic-v3.c b/drivers/irqchip/irq-gic-v3.c index 5b57493f02b2..356ee8fd368a 100644 --- a/drivers/irqchip/irq-gic-v3.c +++ b/drivers/irqchip/irq-gic-v3.c @@ -733,8 +733,38 @@ static void __gic_handle_irq_from_irqsoff(struct pt_regs *regs) __gic_handle_nmi(irqnr, regs); } +#ifdef CONFIG_ARM64 +static inline u64 gic_read_nmiar(void) +{ + u64 irqstat; + + irqstat = read_sysreg_s(SYS_ICC_NMIAR1_EL1); + + dsb(sy); + + return irqstat; +} + +static __always_inline void __el1_nmi(struct pt_regs *regs) +{ + u32 irqnr = gic_read_nmiar(); + + nmi_enter(); + __gic_handle_nmi(irqnr, regs); + nmi_exit(); +} +#endif + static asmlinkage void __exception_irq_entry gic_handle_irq(struct pt_regs *regs) { +#ifdef CONFIG_ARM64 + /* Is there a NMI to handle? */ + if (system_uses_nmi() && (read_sysreg(isr_el1) & ISR_EL1_IS)) { + __el1_nmi(regs); + return; + } +#endif + if (unlikely(gic_supports_nmi() && !interrupts_enabled(regs))) __gic_handle_irq_from_irqsoff(regs); else -- 2.25.1