1 /* 2 * Copyright (C) 1992, 1998 Linus Torvalds, Ingo Molnar 3 * 4 * This file contains the lowest level x86_64-specific interrupt 5 * entry and irq statistics code. All the remaining irq logic is 6 * done by the generic kernel/irq/ code and in the 7 * x86_64-specific irq controller code. (e.g. i8259.c and 8 * io_apic.c.) 9 */ 10 11 #include <linux/kernel_stat.h> 12 #include <linux/interrupt.h> 13 #include <linux/seq_file.h> 14 #include <linux/module.h> 15 #include <linux/delay.h> 16 #include <linux/ftrace.h> 17 #include <linux/uaccess.h> 18 #include <linux/smp.h> 19 #include <asm/io_apic.h> 20 #include <asm/idle.h> 21 22 /* 23 * Probabilistic stack overflow check: 24 * 25 * Only check the stack in process context, because everything else 26 * runs on the big interrupt stacks. Checking reliably is too expensive, 27 * so we just check from interrupts. 28 */ 29 static inline void stack_overflow_check(struct pt_regs *regs) 30 { 31 #ifdef CONFIG_DEBUG_STACKOVERFLOW 32 u64 curbase = (u64)task_stack_page(current); 33 34 WARN_ONCE(regs->sp >= curbase && 35 regs->sp <= curbase + THREAD_SIZE && 36 regs->sp < curbase + sizeof(struct thread_info) + 37 sizeof(struct pt_regs) + 128, 38 39 "do_IRQ: %s near stack overflow (cur:%Lx,sp:%lx)\n", 40 current->comm, curbase, regs->sp); 41 #endif 42 } 43 44 /* 45 * do_IRQ handles all normal device IRQ's (the special 46 * SMP cross-CPU interrupts have their own specific 47 * handlers). 48 */ 49 asmlinkage unsigned int __irq_entry do_IRQ(struct pt_regs *regs) 50 { 51 struct pt_regs *old_regs = set_irq_regs(regs); 52 struct irq_desc *desc; 53 54 /* high bit used in ret_from_ code */ 55 unsigned vector = ~regs->orig_ax; 56 unsigned irq; 57 58 exit_idle(); 59 irq_enter(); 60 irq = __get_cpu_var(vector_irq)[vector]; 61 62 stack_overflow_check(regs); 63 64 desc = irq_to_desc(irq); 65 if (likely(desc)) 66 generic_handle_irq_desc(irq, desc); 67 else { 68 if (!disable_apic) 69 ack_APIC_irq(); 70 71 if (printk_ratelimit()) 72 printk(KERN_EMERG "%s: %d.%d No irq handler for vector\n", 73 __func__, smp_processor_id(), vector); 74 } 75 76 irq_exit(); 77 78 set_irq_regs(old_regs); 79 return 1; 80 } 81 82 #ifdef CONFIG_HOTPLUG_CPU 83 /* A cpu has been removed from cpu_online_mask. Reset irq affinities. */ 84 void fixup_irqs(void) 85 { 86 unsigned int irq; 87 static int warned; 88 struct irq_desc *desc; 89 90 for_each_irq_desc(irq, desc) { 91 int break_affinity = 0; 92 int set_affinity = 1; 93 const struct cpumask *affinity; 94 95 if (!desc) 96 continue; 97 if (irq == 2) 98 continue; 99 100 /* interrupt's are disabled at this point */ 101 spin_lock(&desc->lock); 102 103 affinity = &desc->affinity; 104 if (!irq_has_action(irq) || 105 cpumask_equal(affinity, cpu_online_mask)) { 106 spin_unlock(&desc->lock); 107 continue; 108 } 109 110 if (cpumask_any_and(affinity, cpu_online_mask) >= nr_cpu_ids) { 111 break_affinity = 1; 112 affinity = cpu_all_mask; 113 } 114 115 if (desc->chip->mask) 116 desc->chip->mask(irq); 117 118 if (desc->chip->set_affinity) 119 desc->chip->set_affinity(irq, affinity); 120 else if (!(warned++)) 121 set_affinity = 0; 122 123 if (desc->chip->unmask) 124 desc->chip->unmask(irq); 125 126 spin_unlock(&desc->lock); 127 128 if (break_affinity && set_affinity) 129 printk("Broke affinity for irq %i\n", irq); 130 else if (!set_affinity) 131 printk("Cannot set affinity for irq %i\n", irq); 132 } 133 134 /* That doesn't seem sufficient. Give it 1ms. */ 135 local_irq_enable(); 136 mdelay(1); 137 local_irq_disable(); 138 } 139 #endif 140 141 extern void call_softirq(void); 142 143 asmlinkage void do_softirq(void) 144 { 145 __u32 pending; 146 unsigned long flags; 147 148 if (in_interrupt()) 149 return; 150 151 local_irq_save(flags); 152 pending = local_softirq_pending(); 153 /* Switch to interrupt stack */ 154 if (pending) { 155 call_softirq(); 156 WARN_ON_ONCE(softirq_count()); 157 } 158 local_irq_restore(flags); 159 } 160