diff options
Diffstat (limited to 'arch/arm64/include/asm')
| -rw-r--r-- | arch/arm64/include/asm/arch_gicv3.h | 4 | ||||
| -rw-r--r-- | arch/arm64/include/asm/daifflags.h | 68 | ||||
| -rw-r--r-- | arch/arm64/include/asm/irqflags.h | 67 | ||||
| -rw-r--r-- | arch/arm64/include/asm/kvm_host.h | 7 | ||||
| -rw-r--r-- | arch/arm64/include/asm/ptrace.h | 10 |
5 files changed, 83 insertions, 73 deletions
diff --git a/arch/arm64/include/asm/arch_gicv3.h b/arch/arm64/include/asm/arch_gicv3.h index 14b41ddc68ba..9e991b628706 100644 --- a/arch/arm64/include/asm/arch_gicv3.h +++ b/arch/arm64/include/asm/arch_gicv3.h @@ -163,7 +163,9 @@ static inline bool gic_prio_masking_enabled(void) static inline void gic_pmr_mask_irqs(void) { - BUILD_BUG_ON(GICD_INT_DEF_PRI <= GIC_PRIO_IRQOFF); + BUILD_BUG_ON(GICD_INT_DEF_PRI < (GIC_PRIO_IRQOFF | + GIC_PRIO_PSR_I_SET)); + BUILD_BUG_ON(GICD_INT_DEF_PRI >= GIC_PRIO_IRQON); gic_write_pmr(GIC_PRIO_IRQOFF); } diff --git a/arch/arm64/include/asm/daifflags.h b/arch/arm64/include/asm/daifflags.h index db452aa9e651..f93204f319da 100644 --- a/arch/arm64/include/asm/daifflags.h +++ b/arch/arm64/include/asm/daifflags.h @@ -18,6 +18,7 @@ #include <linux/irqflags.h> +#include <asm/arch_gicv3.h> #include <asm/cpufeature.h> #define DAIF_PROCCTX 0 @@ -32,6 +33,11 @@ static inline void local_daif_mask(void) : : : "memory"); + + /* Don't really care for a dsb here, we don't intend to enable IRQs */ + if (system_uses_irq_prio_masking()) + gic_write_pmr(GIC_PRIO_IRQON | GIC_PRIO_PSR_I_SET); + trace_hardirqs_off(); } @@ -43,7 +49,7 @@ static inline unsigned long local_daif_save(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_IRQOFF) + if (read_sysreg_s(SYS_ICC_PMR_EL1) != GIC_PRIO_IRQON) flags |= PSR_I_BIT; } @@ -59,36 +65,44 @@ static inline void local_daif_restore(unsigned long flags) if (!irq_disabled) { trace_hardirqs_on(); - if (system_uses_irq_prio_masking()) - arch_local_irq_enable(); - } else if (!(flags & PSR_A_BIT)) { - /* - * If interrupts are disabled but we can take - * asynchronous errors, we can take NMIs - */ if (system_uses_irq_prio_masking()) { - flags &= ~PSR_I_BIT; + gic_write_pmr(GIC_PRIO_IRQON); + dsb(sy); + } + } else if (system_uses_irq_prio_masking()) { + u64 pmr; + + if (!(flags & PSR_A_BIT)) { /* - * There has been concern that the write to daif - * might be reordered before this write to PMR. - * From the ARM ARM DDI 0487D.a, section D1.7.1 - * "Accessing PSTATE fields": - * Writes to the PSTATE fields have side-effects on - * various aspects of the PE operation. All of these - * side-effects are guaranteed: - * - Not to be visible to earlier instructions in - * the execution stream. - * - To be visible to later instructions in the - * execution stream - * - * Also, writes to PMR are self-synchronizing, so no - * interrupts with a lower priority than PMR is signaled - * to the PE after the write. - * - * So we don't need additional synchronization here. + * If interrupts are disabled but we can take + * asynchronous errors, we can take NMIs */ - arch_local_irq_disable(); + flags &= ~PSR_I_BIT; + pmr = GIC_PRIO_IRQOFF; + } else { + pmr = GIC_PRIO_IRQON | GIC_PRIO_PSR_I_SET; } + + /* + * There has been concern that the write to daif + * might be reordered before this write to PMR. + * From the ARM ARM DDI 0487D.a, section D1.7.1 + * "Accessing PSTATE fields": + * Writes to the PSTATE fields have side-effects on + * various aspects of the PE operation. All of these + * side-effects are guaranteed: + * - Not to be visible to earlier instructions in + * the execution stream. + * - To be visible to later instructions in the + * execution stream + * + * Also, writes to PMR are self-synchronizing, so no + * interrupts with a lower priority than PMR is signaled + * to the PE after the write. + * + * So we don't need additional synchronization here. + */ + gic_write_pmr(pmr); } write_sysreg(flags, daif); diff --git a/arch/arm64/include/asm/irqflags.h b/arch/arm64/include/asm/irqflags.h index fbe1aba6ffb3..a1372722f12e 100644 --- a/arch/arm64/include/asm/irqflags.h +++ b/arch/arm64/include/asm/irqflags.h @@ -67,43 +67,46 @@ static inline void arch_local_irq_disable(void) */ static inline unsigned long arch_local_save_flags(void) { - unsigned long daif_bits; unsigned long flags; - daif_bits = read_sysreg(daif); - - /* - * The asm is logically equivalent to: - * - * if (system_uses_irq_prio_masking()) - * flags = (daif_bits & PSR_I_BIT) ? - * GIC_PRIO_IRQOFF : - * read_sysreg_s(SYS_ICC_PMR_EL1); - * else - * flags = daif_bits; - */ asm volatile(ALTERNATIVE( - "mov %0, %1\n" - "nop\n" - "nop", - __mrs_s("%0", SYS_ICC_PMR_EL1) - "ands %1, %1, " __stringify(PSR_I_BIT) "\n" - "csel %0, %0, %2, eq", - ARM64_HAS_IRQ_PRIO_MASKING) - : "=&r" (flags), "+r" (daif_bits) - : "r" ((unsigned long) GIC_PRIO_IRQOFF) - : "cc", "memory"); + "mrs %0, daif", + __mrs_s("%0", SYS_ICC_PMR_EL1), + ARM64_HAS_IRQ_PRIO_MASKING) + : "=&r" (flags) + : + : "memory"); return flags; } +static inline int arch_irqs_disabled_flags(unsigned long flags) +{ + int res; + + asm volatile(ALTERNATIVE( + "and %w0, %w1, #" __stringify(PSR_I_BIT), + "eor %w0, %w1, #" __stringify(GIC_PRIO_IRQON), + ARM64_HAS_IRQ_PRIO_MASKING) + : "=&r" (res) + : "r" ((int) flags) + : "memory"); + + return res; +} + static inline unsigned long arch_local_irq_save(void) { unsigned long flags; flags = arch_local_save_flags(); - arch_local_irq_disable(); + /* + * There are too many states with IRQs disabled, just keep the current + * state if interrupts are already disabled/masked. + */ + if (!arch_irqs_disabled_flags(flags)) + arch_local_irq_disable(); return flags; } @@ -124,21 +127,5 @@ static inline void arch_local_irq_restore(unsigned long flags) : "memory"); } -static inline int arch_irqs_disabled_flags(unsigned long flags) -{ - int res; - - asm volatile(ALTERNATIVE( - "and %w0, %w1, #" __stringify(PSR_I_BIT) "\n" - "nop", - "cmp %w1, #" __stringify(GIC_PRIO_IRQOFF) "\n" - "cset %w0, ls", - ARM64_HAS_IRQ_PRIO_MASKING) - : "=&r" (res) - : "r" ((int) flags) - : "cc", "memory"); - - return res; -} #endif #endif diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h index 4bcd9c1291d5..33410635b015 100644 --- a/arch/arm64/include/asm/kvm_host.h +++ b/arch/arm64/include/asm/kvm_host.h @@ -608,11 +608,12 @@ static inline void kvm_arm_vhe_guest_enter(void) * will not signal the CPU of interrupts of lower priority, and the * only way to get out will be via guest exceptions. * Naturally, we want to avoid this. + * + * local_daif_mask() already sets GIC_PRIO_PSR_I_SET, we just need a + * dsb to ensure the redistributor is forwards EL2 IRQs to the CPU. */ - if (system_uses_irq_prio_masking()) { - gic_write_pmr(GIC_PRIO_IRQON); + if (system_uses_irq_prio_masking()) dsb(sy); - } } static inline void kvm_arm_vhe_guest_exit(void) diff --git a/arch/arm64/include/asm/ptrace.h b/arch/arm64/include/asm/ptrace.h index b2de32939ada..da2242248466 100644 --- a/arch/arm64/include/asm/ptrace.h +++ b/arch/arm64/include/asm/ptrace.h @@ -35,9 +35,15 @@ * means masking more IRQs (or at least that the same IRQs remain masked). * * To mask interrupts, we clear the most significant bit of PMR. + * + * Some code sections either automatically switch back to PSR.I or explicitly + * require to not use priority masking. If bit GIC_PRIO_PSR_I_SET is included + * in the the priority mask, it indicates that PSR.I should be set and + * interrupt disabling temporarily does not rely on IRQ priorities. */ -#define GIC_PRIO_IRQON 0xf0 -#define GIC_PRIO_IRQOFF (GIC_PRIO_IRQON & ~0x80) +#define GIC_PRIO_IRQON 0xc0 +#define GIC_PRIO_IRQOFF (GIC_PRIO_IRQON & ~0x80) +#define GIC_PRIO_PSR_I_SET (1 << 4) /* Additional SPSR bits not exposed in the UABI */ #define PSR_IL_BIT (1 << 20) |