From f0098155d337cab638cf18e37a3e9257d653d481 Mon Sep 17 00:00:00 2001 From: Hector Martin Date: Mon, 15 Mar 2021 11:56:28 +0000 Subject: [PATCH] arm64: Always keep DAIF.[IF] in sync Apple SoCs (A11 and newer) have some interrupt sources hardwired to the FIQ line. We implement support for this by simply treating IRQs and FIQs the same way in the interrupt vectors. To support these systems, the FIQ mask bit needs to be kept in sync with the IRQ mask bit, so both kinds of exceptions are masked together. No other platforms should be delivering FIQ exceptions right now, and we already unmask FIQ in normal process context, so this should not have an effect on other systems - if spurious FIQs were arriving, they would already panic the kernel. Signed-off-by: Hector Martin Signed-off-by: Mark Rutland Tested-by: Hector Martin Cc: James Morse Cc: Marc Zyngier Cc: Thomas Gleixner Cc: Will Deacon Acked-by: Will Deacon Link: https://lore.kernel.org/r/20210315115629.57191-6-mark.rutland@arm.com Signed-off-by: Catalin Marinas --- arch/arm64/include/asm/arch_gicv3.h | 2 +- arch/arm64/include/asm/assembler.h | 8 ++++---- arch/arm64/include/asm/daifflags.h | 10 +++++----- arch/arm64/include/asm/irqflags.h | 16 +++++++--------- arch/arm64/kernel/entry.S | 12 +++++++----- arch/arm64/kernel/process.c | 2 +- arch/arm64/kernel/smp.c | 1 + 7 files changed, 26 insertions(+), 25 deletions(-) diff --git a/arch/arm64/include/asm/arch_gicv3.h b/arch/arm64/include/asm/arch_gicv3.h index 880b905..934b9be 100644 --- a/arch/arm64/include/asm/arch_gicv3.h +++ b/arch/arm64/include/asm/arch_gicv3.h @@ -173,7 +173,7 @@ static inline void gic_pmr_mask_irqs(void) static inline void gic_arch_enable_irqs(void) { - asm volatile ("msr daifclr, #2" : : : "memory"); + asm volatile ("msr daifclr, #3" : : : "memory"); } #endif /* __ASSEMBLY__ */ diff --git a/arch/arm64/include/asm/assembler.h b/arch/arm64/include/asm/assembler.h index ca31594..b76a71e 100644 --- a/arch/arm64/include/asm/assembler.h +++ b/arch/arm64/include/asm/assembler.h @@ -40,9 +40,9 @@ msr daif, \flags .endm - /* IRQ is the lowest priority flag, unconditionally unmask the rest. */ - .macro enable_da_f - msr daifclr, #(8 | 4 | 1) + /* IRQ/FIQ are the lowest priority flags, unconditionally unmask the rest. */ + .macro enable_da + msr daifclr, #(8 | 4) .endm /* @@ -50,7 +50,7 @@ */ .macro save_and_disable_irq, flags mrs \flags, daif - msr daifset, #2 + msr daifset, #3 .endm .macro restore_irq, flags diff --git a/arch/arm64/include/asm/daifflags.h b/arch/arm64/include/asm/daifflags.h index 1c26d7b..5eb7af9 100644 --- a/arch/arm64/include/asm/daifflags.h +++ b/arch/arm64/include/asm/daifflags.h @@ -13,8 +13,8 @@ #include #define DAIF_PROCCTX 0 -#define DAIF_PROCCTX_NOIRQ PSR_I_BIT -#define DAIF_ERRCTX (PSR_I_BIT | PSR_A_BIT) +#define DAIF_PROCCTX_NOIRQ (PSR_I_BIT | PSR_F_BIT) +#define DAIF_ERRCTX (PSR_A_BIT | PSR_I_BIT | PSR_F_BIT) #define DAIF_MASK (PSR_D_BIT | PSR_A_BIT | PSR_I_BIT | PSR_F_BIT) @@ -47,7 +47,7 @@ static inline unsigned long local_daif_save_flags(void) if (system_uses_irq_prio_masking()) { /* If IRQs are masked with PMR, reflect it in the flags */ if (read_sysreg_s(SYS_ICC_PMR_EL1) != GIC_PRIO_IRQON) - flags |= PSR_I_BIT; + flags |= PSR_I_BIT | PSR_F_BIT; } return flags; @@ -69,7 +69,7 @@ static inline void local_daif_restore(unsigned long flags) bool irq_disabled = flags & PSR_I_BIT; WARN_ON(system_has_prio_mask_debugging() && - !(read_sysreg(daif) & PSR_I_BIT)); + (read_sysreg(daif) & (PSR_I_BIT | PSR_F_BIT)) != (PSR_I_BIT | PSR_F_BIT)); if (!irq_disabled) { trace_hardirqs_on(); @@ -86,7 +86,7 @@ static inline void local_daif_restore(unsigned long flags) * If interrupts are disabled but we can take * asynchronous errors, we can take NMIs */ - flags &= ~PSR_I_BIT; + flags &= ~(PSR_I_BIT | PSR_F_BIT); pmr = GIC_PRIO_IRQOFF; } else { pmr = GIC_PRIO_IRQON | GIC_PRIO_PSR_I_SET; diff --git a/arch/arm64/include/asm/irqflags.h b/arch/arm64/include/asm/irqflags.h index ff328e5b..b57b9b1 100644 --- a/arch/arm64/include/asm/irqflags.h +++ b/arch/arm64/include/asm/irqflags.h @@ -12,15 +12,13 @@ /* * Aarch64 has flags for masking: Debug, Asynchronous (serror), Interrupts and - * FIQ exceptions, in the 'daif' register. We mask and unmask them in 'dai' + * FIQ exceptions, in the 'daif' register. We mask and unmask them in 'daif' * order: * Masking debug exceptions causes all other exceptions to be masked too/ - * Masking SError masks irq, but not debug exceptions. Masking irqs has no - * side effects for other flags. Keeping to this order makes it easier for - * entry.S to know which exceptions should be unmasked. - * - * FIQ is never expected, but we mask it when we disable debug exceptions, and - * unmask it at all other times. + * Masking SError masks IRQ/FIQ, but not debug exceptions. IRQ and FIQ are + * always masked and unmasked together, and have no side effects for other + * flags. Keeping to this order makes it easier for entry.S to know which + * exceptions should be unmasked. */ /* @@ -35,7 +33,7 @@ static inline void arch_local_irq_enable(void) } asm volatile(ALTERNATIVE( - "msr daifclr, #2 // arch_local_irq_enable", + "msr daifclr, #3 // arch_local_irq_enable", __msr_s(SYS_ICC_PMR_EL1, "%0"), ARM64_HAS_IRQ_PRIO_MASKING) : @@ -54,7 +52,7 @@ static inline void arch_local_irq_disable(void) } asm volatile(ALTERNATIVE( - "msr daifset, #2 // arch_local_irq_disable", + "msr daifset, #3 // arch_local_irq_disable", __msr_s(SYS_ICC_PMR_EL1, "%0"), ARM64_HAS_IRQ_PRIO_MASKING) : diff --git a/arch/arm64/kernel/entry.S b/arch/arm64/kernel/entry.S index e235b0e..ce8d4dc 100644 --- a/arch/arm64/kernel/entry.S +++ b/arch/arm64/kernel/entry.S @@ -533,7 +533,7 @@ alternative_endif .macro el1_interrupt_handler, handler:req gic_prio_irq_setup pmr=x20, tmp=x1 - enable_da_f + enable_da mov x0, sp bl enter_el1_irq_or_nmi @@ -544,8 +544,10 @@ alternative_endif ldr x24, [tsk, #TSK_TI_PREEMPT] // get preempt count alternative_if ARM64_HAS_IRQ_PRIO_MASKING /* - * DA_F were cleared at start of handling. If anything is set in DAIF, - * we come back from an NMI, so skip preemption + * DA were cleared at start of handling, and IF are cleared by + * the GIC irqchip driver using gic_arch_enable_irqs() for + * normal IRQs. If anything is set, it means we come back from + * an NMI instead of a normal IRQ, so skip preemption */ mrs x0, daif orr x24, x24, x0 @@ -562,7 +564,7 @@ alternative_else_nop_endif .macro el0_interrupt_handler, handler:req gic_prio_irq_setup pmr=x20, tmp=x0 user_exit_irqoff - enable_da_f + enable_da tbz x22, #55, 1f bl do_el0_irq_bp_hardening @@ -763,7 +765,7 @@ el0_error_naked: mov x0, sp mov x1, x25 bl do_serror - enable_da_f + enable_da b ret_to_user SYM_CODE_END(el0_error) diff --git a/arch/arm64/kernel/process.c b/arch/arm64/kernel/process.c index 325c83b..a29028d 100644 --- a/arch/arm64/kernel/process.c +++ b/arch/arm64/kernel/process.c @@ -84,7 +84,7 @@ static void noinstr __cpu_do_idle_irqprio(void) unsigned long daif_bits; daif_bits = read_sysreg(daif); - write_sysreg(daif_bits | PSR_I_BIT, daif); + write_sysreg(daif_bits | PSR_I_BIT | PSR_F_BIT, daif); /* * Unmask PMR before going idle to make sure interrupts can diff --git a/arch/arm64/kernel/smp.c b/arch/arm64/kernel/smp.c index 357590b..dcd7041 100644 --- a/arch/arm64/kernel/smp.c +++ b/arch/arm64/kernel/smp.c @@ -188,6 +188,7 @@ static void init_gic_priority_masking(void) cpuflags = read_sysreg(daif); WARN_ON(!(cpuflags & PSR_I_BIT)); + WARN_ON(!(cpuflags & PSR_F_BIT)); gic_write_pmr(GIC_PRIO_IRQON | GIC_PRIO_PSR_I_SET); } -- 2.7.4