diff options
Diffstat (limited to 'arch/powerpc/kernel/irq.c')
-rw-r--r-- | arch/powerpc/kernel/irq.c | 212 |
1 files changed, 141 insertions, 71 deletions
diff --git a/arch/powerpc/kernel/irq.c b/arch/powerpc/kernel/irq.c index bdfb3eee3e6f..a3d128e94cff 100644 --- a/arch/powerpc/kernel/irq.c +++ b/arch/powerpc/kernel/irq.c @@ -93,20 +93,16 @@ extern int tau_interrupts(int); #ifdef CONFIG_PPC64 -#ifndef CONFIG_SPARSE_IRQ -EXPORT_SYMBOL(irq_desc); -#endif - int distribute_irqs = 1; -static inline notrace unsigned long get_hard_enabled(void) +static inline notrace unsigned long get_irq_happened(void) { - unsigned long enabled; + unsigned long happened; __asm__ __volatile__("lbz %0,%1(13)" - : "=r" (enabled) : "i" (offsetof(struct paca_struct, hard_enabled))); + : "=r" (happened) : "i" (offsetof(struct paca_struct, irq_happened))); - return enabled; + return happened; } static inline notrace void set_soft_enabled(unsigned long enable) @@ -115,88 +111,162 @@ static inline notrace void set_soft_enabled(unsigned long enable) : : "r" (enable), "i" (offsetof(struct paca_struct, soft_enabled))); } -static inline notrace void decrementer_check_overflow(void) +static inline notrace int decrementer_check_overflow(void) { - u64 now = get_tb_or_rtc(); - u64 *next_tb; - - preempt_disable(); - next_tb = &__get_cpu_var(decrementers_next_tb); - + u64 now = get_tb_or_rtc(); + u64 *next_tb = &__get_cpu_var(decrementers_next_tb); + if (now >= *next_tb) set_dec(1); - preempt_enable(); + return now >= *next_tb; } -notrace void arch_local_irq_restore(unsigned long en) +/* This is called whenever we are re-enabling interrupts + * and returns either 0 (nothing to do) or 500/900 if there's + * either an EE or a DEC to generate. + * + * This is called in two contexts: From arch_local_irq_restore() + * before soft-enabling interrupts, and from the exception exit + * path when returning from an interrupt from a soft-disabled to + * a soft enabled context. In both case we have interrupts hard + * disabled. + * + * We take care of only clearing the bits we handled in the + * PACA irq_happened field since we can only re-emit one at a + * time and we don't want to "lose" one. + */ +notrace unsigned int __check_irq_replay(void) { /* - * get_paca()->soft_enabled = en; - * Is it ever valid to use local_irq_restore(0) when soft_enabled is 1? - * That was allowed before, and in such a case we do need to take care - * that gcc will set soft_enabled directly via r13, not choose to use - * an intermediate register, lest we're preempted to a different cpu. + * We use local_paca rather than get_paca() to avoid all + * the debug_smp_processor_id() business in this low level + * function */ - set_soft_enabled(en); - if (!en) - return; + unsigned char happened = local_paca->irq_happened; -#ifdef CONFIG_PPC_STD_MMU_64 - if (firmware_has_feature(FW_FEATURE_ISERIES)) { - /* - * Do we need to disable preemption here? Not really: in the - * unlikely event that we're preempted to a different cpu in - * between getting r13, loading its lppaca_ptr, and loading - * its any_int, we might call iseries_handle_interrupts without - * an interrupt pending on the new cpu, but that's no disaster, - * is it? And the business of preempting us off the old cpu - * would itself involve a local_irq_restore which handles the - * interrupt to that cpu. - * - * But use "local_paca->lppaca_ptr" instead of "get_lppaca()" - * to avoid any preemption checking added into get_paca(). - */ - if (local_paca->lppaca_ptr->int_dword.any_int) - iseries_handle_interrupts(); + /* Clear bit 0 which we wouldn't clear otherwise */ + local_paca->irq_happened &= ~PACA_IRQ_HARD_DIS; + + /* + * Force the delivery of pending soft-disabled interrupts on PS3. + * Any HV call will have this side effect. + */ + if (firmware_has_feature(FW_FEATURE_PS3_LV1)) { + u64 tmp, tmp2; + lv1_get_version_info(&tmp, &tmp2); } -#endif /* CONFIG_PPC_STD_MMU_64 */ /* - * if (get_paca()->hard_enabled) return; - * But again we need to take care that gcc gets hard_enabled directly - * via r13, not choose to use an intermediate register, lest we're - * preempted to a different cpu in between the two instructions. + * We may have missed a decrementer interrupt. We check the + * decrementer itself rather than the paca irq_happened field + * in case we also had a rollover while hard disabled + */ + local_paca->irq_happened &= ~PACA_IRQ_DEC; + if (decrementer_check_overflow()) + return 0x900; + + /* Finally check if an external interrupt happened */ + local_paca->irq_happened &= ~PACA_IRQ_EE; + if (happened & PACA_IRQ_EE) + return 0x500; + +#ifdef CONFIG_PPC_BOOK3E + /* Finally check if an EPR external interrupt happened + * this bit is typically set if we need to handle another + * "edge" interrupt from within the MPIC "EPR" handler */ - if (get_hard_enabled()) + local_paca->irq_happened &= ~PACA_IRQ_EE_EDGE; + if (happened & PACA_IRQ_EE_EDGE) + return 0x500; + + local_paca->irq_happened &= ~PACA_IRQ_DBELL; + if (happened & PACA_IRQ_DBELL) + return 0x280; +#endif /* CONFIG_PPC_BOOK3E */ + + /* There should be nothing left ! */ + BUG_ON(local_paca->irq_happened != 0); + + return 0; +} + +notrace void arch_local_irq_restore(unsigned long en) +{ + unsigned char irq_happened; + unsigned int replay; + + /* Write the new soft-enabled value */ + set_soft_enabled(en); + if (!en) + return; + /* + * From this point onward, we can take interrupts, preempt, + * etc... unless we got hard-disabled. We check if an event + * happened. If none happened, we know we can just return. + * + * We may have preempted before the check below, in which case + * we are checking the "new" CPU instead of the old one. This + * is only a problem if an event happened on the "old" CPU. + * + * External interrupt events on non-iseries will have caused + * interrupts to be hard-disabled, so there is no problem, we + * cannot have preempted. + */ + irq_happened = get_irq_happened(); + if (!irq_happened) return; /* - * Need to hard-enable interrupts here. Since currently disabled, - * no need to take further asm precautions against preemption; but - * use local_paca instead of get_paca() to avoid preemption checking. + * We need to hard disable to get a trusted value from + * __check_irq_replay(). We also need to soft-disable + * again to avoid warnings in there due to the use of + * per-cpu variables. + * + * We know that if the value in irq_happened is exactly 0x01 + * then we are already hard disabled (there are other less + * common cases that we'll ignore for now), so we skip the + * (expensive) mtmsrd. */ - local_paca->hard_enabled = en; + if (unlikely(irq_happened != PACA_IRQ_HARD_DIS)) + __hard_irq_disable(); + set_soft_enabled(0); /* - * Trigger the decrementer if we have a pending event. Some processors - * only trigger on edge transitions of the sign bit. We might also - * have disabled interrupts long enough that the decrementer wrapped - * to positive. + * Check if anything needs to be re-emitted. We haven't + * soft-enabled yet to avoid warnings in decrementer_check_overflow + * accessing per-cpu variables */ - decrementer_check_overflow(); + replay = __check_irq_replay(); + + /* We can soft-enable now */ + set_soft_enabled(1); /* - * Force the delivery of pending soft-disabled interrupts on PS3. - * Any HV call will have this side effect. + * And replay if we have to. This will return with interrupts + * hard-enabled. */ - if (firmware_has_feature(FW_FEATURE_PS3_LV1)) { - u64 tmp, tmp2; - lv1_get_version_info(&tmp, &tmp2); + if (replay) { + __replay_interrupt(replay); + return; } + /* Finally, let's ensure we are hard enabled */ __hard_irq_enable(); } EXPORT_SYMBOL(arch_local_irq_restore); + +/* + * This is specifically called by assembly code to re-enable interrupts + * if they are currently disabled. This is typically called before + * schedule() or do_signal() when returning to userspace. We do it + * in C to avoid the burden of dealing with lockdep etc... + */ +void restore_interrupts(void) +{ + if (irqs_disabled()) + local_irq_enable(); +} + #endif /* CONFIG_PPC64 */ int arch_show_interrupts(struct seq_file *p, int prec) @@ -364,8 +434,17 @@ void do_IRQ(struct pt_regs *regs) check_stack_overflow(); + /* + * Query the platform PIC for the interrupt & ack it. + * + * This will typically lower the interrupt line to the CPU + */ irq = ppc_md.get_irq(); + /* We can hard enable interrupts now */ + may_hard_irq_enable(); + + /* And finally process it */ if (irq != NO_IRQ && irq != NO_IRQ_IGNORE) handle_one_irq(irq); else if (irq != NO_IRQ_IGNORE) @@ -374,15 +453,6 @@ void do_IRQ(struct pt_regs *regs) irq_exit(); set_irq_regs(old_regs); -#ifdef CONFIG_PPC_ISERIES - if (firmware_has_feature(FW_FEATURE_ISERIES) && - get_lppaca()->int_dword.fields.decr_int) { - get_lppaca()->int_dword.fields.decr_int = 0; - /* Signal a fake decrementer interrupt */ - timer_interrupt(regs); - } -#endif - trace_irq_exit(regs); } |