diff options
| -rw-r--r-- | arch/powerpc/kernel/time.c | 44 |
1 files changed, 13 insertions, 31 deletions
diff --git a/arch/powerpc/kernel/time.c b/arch/powerpc/kernel/time.c index 2d9d3a3c61d6..6fcae436ae51 100644 --- a/arch/powerpc/kernel/time.c +++ b/arch/powerpc/kernel/time.c @@ -522,35 +522,6 @@ static inline void clear_irq_work_pending(void) "i" (offsetof(struct paca_struct, irq_work_pending))); } -void arch_irq_work_raise(void) -{ - preempt_disable(); - set_irq_work_pending_flag(); - /* - * Non-nmi code running with interrupts disabled will replay - * irq_happened before it re-enables interrupts, so setthe - * decrementer there instead of causing a hardware exception - * which would immediately hit the masked interrupt handler - * and have the net effect of setting the decrementer in - * irq_happened. - * - * NMI interrupts can not check this when they return, so the - * decrementer hardware exception is raised, which will fire - * when interrupts are next enabled. - * - * BookE does not support this yet, it must audit all NMI - * interrupt handlers to ensure they call nmi_enter() so this - * check would be correct. - */ - if (IS_ENABLED(CONFIG_BOOKE) || !irqs_disabled() || in_nmi()) { - set_dec(1); - } else { - hard_irq_disable(); - local_paca->irq_happened |= PACA_IRQ_DEC; - } - preempt_enable(); -} - #else /* 32-bit */ DEFINE_PER_CPU(u8, irq_work_pending); @@ -559,16 +530,27 @@ DEFINE_PER_CPU(u8, irq_work_pending); #define test_irq_work_pending() __this_cpu_read(irq_work_pending) #define clear_irq_work_pending() __this_cpu_write(irq_work_pending, 0) +#endif /* 32 vs 64 bit */ + void arch_irq_work_raise(void) { + /* + * 64-bit code that uses irq soft-mask can just cause an immediate + * interrupt here that gets soft masked, if this is called under + * local_irq_disable(). It might be possible to prevent that happening + * by noticing interrupts are disabled and setting decrementer pending + * to be replayed when irqs are enabled. The problem there is that + * tracing can call irq_work_raise, including in code that does low + * level manipulations of irq soft-mask state (e.g., trace_hardirqs_on) + * which could get tangled up if we're messing with the same state + * here. + */ preempt_disable(); set_irq_work_pending_flag(); set_dec(1); preempt_enable(); } -#endif /* 32 vs 64 bit */ - #else /* CONFIG_IRQ_WORK */ #define test_irq_work_pending() 0 |