diff options
Diffstat (limited to 'arch/powerpc/kernel/irq.c')
| -rw-r--r-- | arch/powerpc/kernel/irq.c | 41 |
1 files changed, 38 insertions, 3 deletions
diff --git a/arch/powerpc/kernel/irq.c b/arch/powerpc/kernel/irq.c index 4e65bf82f5e0..4813b83b22aa 100644 --- a/arch/powerpc/kernel/irq.c +++ b/arch/powerpc/kernel/irq.c @@ -394,11 +394,19 @@ bool prep_irq_for_idle_irqsoff(void) /* * Take the SRR1 wakeup reason, index into this table to find the * appropriate irq_happened bit. + * + * Sytem reset exceptions taken in idle state also come through here, + * but they are NMI interrupts so do not need to wait for IRQs to be + * restored, and should be taken as early as practical. These are marked + * with 0xff in the table. The Power ISA specifies 0100b as the system + * reset interrupt reason. */ +#define IRQ_SYSTEM_RESET 0xff + static const u8 srr1_to_lazyirq[0x10] = { 0, 0, 0, PACA_IRQ_DBELL, - 0, + IRQ_SYSTEM_RESET, PACA_IRQ_DBELL, PACA_IRQ_DEC, 0, @@ -407,15 +415,42 @@ static const u8 srr1_to_lazyirq[0x10] = { PACA_IRQ_HMI, 0, 0, 0, 0, 0 }; +static noinline void replay_system_reset(void) +{ + struct pt_regs regs; + + ppc_save_regs(®s); + regs.trap = 0x100; + get_paca()->in_nmi = 1; + system_reset_exception(®s); + get_paca()->in_nmi = 0; +} + void irq_set_pending_from_srr1(unsigned long srr1) { unsigned int idx = (srr1 & SRR1_WAKEMASK_P8) >> 18; + u8 reason = srr1_to_lazyirq[idx]; + + /* + * Take the system reset now, which is immediately after registers + * are restored from idle. It's an NMI, so interrupts need not be + * re-enabled before it is taken. + */ + if (unlikely(reason == IRQ_SYSTEM_RESET)) { + replay_system_reset(); + return; + } /* * The 0 index (SRR1[42:45]=b0000) must always evaluate to 0, - * so this can be called unconditionally with srr1 wake reason. + * so this can be called unconditionally with the SRR1 wake + * reason as returned by the idle code, which uses 0 to mean no + * interrupt. + * + * If a future CPU was to designate this as an interrupt reason, + * then a new index for no interrupt must be assigned. */ - local_paca->irq_happened |= srr1_to_lazyirq[idx]; + local_paca->irq_happened |= reason; } #endif /* CONFIG_PPC_BOOK3S */ |