Messages in this thread Patch in this message | | | From | Julien Thierry <> | Subject | [PATCH v2 4/5] arm64: irqflags: Introduce explicit debugging for IRQ priorities | Date | Mon, 29 Apr 2019 17:00:06 +0100 |
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Using IRQ priority masking to enable/disable interrupts is a bit sensitive as it requires to deal with both ICC_PMR_EL1 and PSR.I.
Introduce some validity checks to both highlight the states in which functions dealing with IRQ enabling/disabling can (not) be called, and bark a warning when called in an unexpected state.
Since these checks are done on hotpaths, introduce a build option to choose whether to do the checking.
Signed-off-by: Julien Thierry <julien.thierry@arm.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Will Deacon <will.deacon@arm.com> --- arch/arm64/Kconfig | 11 +++++++++++ arch/arm64/include/asm/daifflags.h | 9 +++++++++ arch/arm64/include/asm/irqflags.h | 14 ++++++++++++++ 3 files changed, 34 insertions(+)
diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig index 7e34b9e..3fb38f3 100644 --- a/arch/arm64/Kconfig +++ b/arch/arm64/Kconfig @@ -1359,6 +1359,17 @@ config ARM64_PSEUDO_NMI
If unsure, say N
+if ARM64_PSEUDO_NMI +config ARM64_DEBUG_PRIORITY_MASKING + bool "Debug interrupt priority masking" + help + This adds runtime checks to functions enabling/disabling + interrupts when using priority masking. The additional checks verify + the validity of ICC_PMR_EL1 when calling concerned functions. + + If unsure, say N +endif + config RELOCATABLE bool help diff --git a/arch/arm64/include/asm/daifflags.h b/arch/arm64/include/asm/daifflags.h index a32ece9..9512968 100644 --- a/arch/arm64/include/asm/daifflags.h +++ b/arch/arm64/include/asm/daifflags.h @@ -28,6 +28,11 @@ /* mask/save/unmask/restore all exceptions, including interrupts. */ static inline void local_daif_mask(void) { + WARN_ON(IS_ENABLED(CONFIG_ARM64_DEBUG_PRIORITY_MASKING) && + system_uses_irq_prio_masking() && + (read_sysreg_s(SYS_ICC_PMR_EL1) == (GIC_PRIO_IRQOFF | + GIC_PRIO_IGNORE_PMR))); + asm volatile( "msr daifset, #0xf // local_daif_mask\n" : @@ -62,6 +67,10 @@ static inline void local_daif_restore(unsigned long flags) { bool irq_disabled = flags & PSR_I_BIT;
+ WARN_ON(IS_ENABLED(CONFIG_ARM64_DEBUG_PRIORITY_MASKING) && + system_uses_irq_prio_masking() && + !(read_sysreg(daif) & PSR_I_BIT)); + if (!irq_disabled) { trace_hardirqs_on();
diff --git a/arch/arm64/include/asm/irqflags.h b/arch/arm64/include/asm/irqflags.h index 516cdfc..a40abc2 100644 --- a/arch/arm64/include/asm/irqflags.h +++ b/arch/arm64/include/asm/irqflags.h @@ -40,6 +40,13 @@ */ static inline void arch_local_irq_enable(void) { + if (IS_ENABLED(CONFIG_ARM64_DEBUG_PRIORITY_MASKING) && + system_uses_irq_prio_masking()) { + u32 pmr = read_sysreg_s(SYS_ICC_PMR_EL1); + + WARN_ON(pmr != GIC_PRIO_IRQON && pmr != GIC_PRIO_IRQOFF); + } + asm volatile(ALTERNATIVE( "msr daifclr, #2 // arch_local_irq_enable\n" "nop", @@ -53,6 +60,13 @@ static inline void arch_local_irq_enable(void)
static inline void arch_local_irq_disable(void) { + if (IS_ENABLED(CONFIG_ARM64_DEBUG_PRIORITY_MASKING) && + system_uses_irq_prio_masking()) { + u32 pmr = read_sysreg_s(SYS_ICC_PMR_EL1); + + WARN_ON(pmr != GIC_PRIO_IRQON && pmr != GIC_PRIO_IRQOFF); + } + asm volatile(ALTERNATIVE( "msr daifset, #2 // arch_local_irq_disable", "msr_s " __stringify(SYS_ICC_PMR_EL1) ", %0", -- 1.9.1
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