From c28548012ee2bac55772ef7685138bd1124b80c3 Mon Sep 17 00:00:00 2001 From: Nicholas Piggin Date: Sat, 21 Jan 2023 20:01:56 +1000 Subject: powerpc/64: Fix perf profiling asynchronous interrupt handlers Interrupt entry sets the soft mask to IRQS_ALL_DISABLED to match the hard irq disabled state. So when should_hard_irq_enable() returns true because we want PMI interrupts in irq handlers, MSR[EE] is enabled but PMIs just get soft-masked. Fix this by clearing IRQS_PMI_DISABLED before enabling MSR[EE]. This also tidies some of the warnings, no need to duplicate them in both should_hard_irq_enable() and do_hard_irq_enable(). Signed-off-by: Nicholas Piggin Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20230121100156.2824054-1-npiggin@gmail.com --- arch/powerpc/include/asm/hw_irq.h | 41 +++++++++++++++++++++++++++------------ arch/powerpc/kernel/dbell.c | 2 +- arch/powerpc/kernel/irq.c | 2 +- arch/powerpc/kernel/time.c | 2 +- 4 files changed, 32 insertions(+), 15 deletions(-) (limited to 'arch/powerpc') diff --git a/arch/powerpc/include/asm/hw_irq.h b/arch/powerpc/include/asm/hw_irq.h index 0b7d01d408ac..eb6d094083fd 100644 --- a/arch/powerpc/include/asm/hw_irq.h +++ b/arch/powerpc/include/asm/hw_irq.h @@ -173,6 +173,15 @@ static inline notrace unsigned long irq_soft_mask_or_return(unsigned long mask) return flags; } +static inline notrace unsigned long irq_soft_mask_andc_return(unsigned long mask) +{ + unsigned long flags = irq_soft_mask_return(); + + irq_soft_mask_set(flags & ~mask); + + return flags; +} + static inline unsigned long arch_local_save_flags(void) { return irq_soft_mask_return(); @@ -331,10 +340,11 @@ bool power_pmu_wants_prompt_pmi(void); * is a different soft-masked interrupt pending that requires hard * masking. */ -static inline bool should_hard_irq_enable(void) +static inline bool should_hard_irq_enable(struct pt_regs *regs) { if (IS_ENABLED(CONFIG_PPC_IRQ_SOFT_MASK_DEBUG)) { - WARN_ON(irq_soft_mask_return() == IRQS_ENABLED); + WARN_ON(irq_soft_mask_return() != IRQS_ALL_DISABLED); + WARN_ON(!(get_paca()->irq_happened & PACA_IRQ_HARD_DIS)); WARN_ON(mfmsr() & MSR_EE); } @@ -347,8 +357,17 @@ static inline bool should_hard_irq_enable(void) * * TODO: Add test for 64e */ - if (IS_ENABLED(CONFIG_PPC_BOOK3S_64) && !power_pmu_wants_prompt_pmi()) - return false; + if (IS_ENABLED(CONFIG_PPC_BOOK3S_64)) { + if (!power_pmu_wants_prompt_pmi()) + return false; + /* + * If PMIs are disabled then IRQs should be disabled as well, + * so we shouldn't see this condition, check for it just in + * case because we are about to enable PMIs. + */ + if (WARN_ON_ONCE(regs->softe & IRQS_PMI_DISABLED)) + return false; + } if (get_paca()->irq_happened & PACA_IRQ_MUST_HARD_MASK) return false; @@ -358,18 +377,16 @@ static inline bool should_hard_irq_enable(void) /* * Do the hard enabling, only call this if should_hard_irq_enable is true. + * This allows PMI interrupts to profile irq handlers. */ static inline void do_hard_irq_enable(void) { - if (IS_ENABLED(CONFIG_PPC_IRQ_SOFT_MASK_DEBUG)) { - WARN_ON(irq_soft_mask_return() == IRQS_ENABLED); - WARN_ON(get_paca()->irq_happened & PACA_IRQ_MUST_HARD_MASK); - WARN_ON(mfmsr() & MSR_EE); - } /* - * This allows PMI interrupts (and watchdog soft-NMIs) through. - * There is no other reason to enable this way. + * Asynch interrupts come in with IRQS_ALL_DISABLED, + * PACA_IRQ_HARD_DIS, and MSR[EE]=0. */ + if (IS_ENABLED(CONFIG_PPC_BOOK3S_64)) + irq_soft_mask_andc_return(IRQS_PMI_DISABLED); get_paca()->irq_happened &= ~PACA_IRQ_HARD_DIS; __hard_irq_enable(); } @@ -452,7 +469,7 @@ static inline bool arch_irq_disabled_regs(struct pt_regs *regs) return !(regs->msr & MSR_EE); } -static __always_inline bool should_hard_irq_enable(void) +static __always_inline bool should_hard_irq_enable(struct pt_regs *regs) { return false; } diff --git a/arch/powerpc/kernel/dbell.c b/arch/powerpc/kernel/dbell.c index f55c6fb34a3a..5712dd846263 100644 --- a/arch/powerpc/kernel/dbell.c +++ b/arch/powerpc/kernel/dbell.c @@ -27,7 +27,7 @@ DEFINE_INTERRUPT_HANDLER_ASYNC(doorbell_exception) ppc_msgsync(); - if (should_hard_irq_enable()) + if (should_hard_irq_enable(regs)) do_hard_irq_enable(); kvmppc_clear_host_ipi(smp_processor_id()); diff --git a/arch/powerpc/kernel/irq.c b/arch/powerpc/kernel/irq.c index c5b9ce887483..c9535f2760b5 100644 --- a/arch/powerpc/kernel/irq.c +++ b/arch/powerpc/kernel/irq.c @@ -238,7 +238,7 @@ static void __do_irq(struct pt_regs *regs, unsigned long oldsp) irq = static_call(ppc_get_irq)(); /* We can hard enable interrupts now to allow perf interrupts */ - if (should_hard_irq_enable()) + if (should_hard_irq_enable(regs)) do_hard_irq_enable(); /* And finally process it */ diff --git a/arch/powerpc/kernel/time.c b/arch/powerpc/kernel/time.c index d68de3618741..e26eb6618ae5 100644 --- a/arch/powerpc/kernel/time.c +++ b/arch/powerpc/kernel/time.c @@ -515,7 +515,7 @@ DEFINE_INTERRUPT_HANDLER_ASYNC(timer_interrupt) } /* Conditionally hard-enable interrupts. */ - if (should_hard_irq_enable()) { + if (should_hard_irq_enable(regs)) { /* * Ensure a positive value is written to the decrementer, or * else some CPUs will continue to take decrementer exceptions. -- cgit v1.2.3