1 /* 2 * linux/arch/alpha/kernel/irq.c 3 * 4 * Copyright (C) 1995 Linus Torvalds 5 * 6 * This file contains the code used by various IRQ handling routines: 7 * asking for different IRQ's should be done through these routines 8 * instead of just grabbing them. Thus setups with different IRQ numbers 9 * shouldn't result in any weird surprises, and installing new handlers 10 * should be easier. 11 */ 12 13 #include <linux/kernel.h> 14 #include <linux/module.h> 15 #include <linux/errno.h> 16 #include <linux/kernel_stat.h> 17 #include <linux/signal.h> 18 #include <linux/sched.h> 19 #include <linux/ptrace.h> 20 #include <linux/interrupt.h> 21 #include <linux/slab.h> 22 #include <linux/random.h> 23 #include <linux/init.h> 24 #include <linux/irq.h> 25 #include <linux/proc_fs.h> 26 #include <linux/seq_file.h> 27 #include <linux/profile.h> 28 #include <linux/bitops.h> 29 30 #include <asm/system.h> 31 #include <asm/io.h> 32 #include <asm/uaccess.h> 33 34 volatile unsigned long irq_err_count; 35 36 void ack_bad_irq(unsigned int irq) 37 { 38 irq_err_count++; 39 printk(KERN_CRIT "Unexpected IRQ trap at vector %u\n", irq); 40 } 41 42 #ifdef CONFIG_SMP 43 static char irq_user_affinity[NR_IRQS]; 44 45 int irq_select_affinity(unsigned int irq) 46 { 47 static int last_cpu; 48 int cpu = last_cpu + 1; 49 50 if (!irq_desc[irq].chip->set_affinity || irq_user_affinity[irq]) 51 return 1; 52 53 while (!cpu_possible(cpu) || 54 !cpumask_test_cpu(cpu, irq_default_affinity)) 55 cpu = (cpu < (NR_CPUS-1) ? cpu + 1 : 0); 56 last_cpu = cpu; 57 58 cpumask_copy(irq_desc[irq].affinity, cpumask_of(cpu)); 59 irq_desc[irq].chip->set_affinity(irq, cpumask_of(cpu)); 60 return 0; 61 } 62 #endif /* CONFIG_SMP */ 63 64 int 65 show_interrupts(struct seq_file *p, void *v) 66 { 67 #ifdef CONFIG_SMP 68 int j; 69 #endif 70 int irq = *(loff_t *) v; 71 struct irqaction * action; 72 unsigned long flags; 73 74 #ifdef CONFIG_SMP 75 if (irq == 0) { 76 seq_puts(p, " "); 77 for_each_online_cpu(j) 78 seq_printf(p, "CPU%d ", j); 79 seq_putc(p, '\n'); 80 } 81 #endif 82 83 if (irq < ACTUAL_NR_IRQS) { 84 raw_spin_lock_irqsave(&irq_desc[irq].lock, flags); 85 action = irq_desc[irq].action; 86 if (!action) 87 goto unlock; 88 seq_printf(p, "%3d: ", irq); 89 #ifndef CONFIG_SMP 90 seq_printf(p, "%10u ", kstat_irqs(irq)); 91 #else 92 for_each_online_cpu(j) 93 seq_printf(p, "%10u ", kstat_irqs_cpu(irq, j)); 94 #endif 95 seq_printf(p, " %14s", irq_desc[irq].chip->name); 96 seq_printf(p, " %c%s", 97 (action->flags & IRQF_DISABLED)?'+':' ', 98 action->name); 99 100 for (action=action->next; action; action = action->next) { 101 seq_printf(p, ", %c%s", 102 (action->flags & IRQF_DISABLED)?'+':' ', 103 action->name); 104 } 105 106 seq_putc(p, '\n'); 107 unlock: 108 raw_spin_unlock_irqrestore(&irq_desc[irq].lock, flags); 109 } else if (irq == ACTUAL_NR_IRQS) { 110 #ifdef CONFIG_SMP 111 seq_puts(p, "IPI: "); 112 for_each_online_cpu(j) 113 seq_printf(p, "%10lu ", cpu_data[j].ipi_count); 114 seq_putc(p, '\n'); 115 #endif 116 seq_printf(p, "ERR: %10lu\n", irq_err_count); 117 } 118 return 0; 119 } 120 121 /* 122 * handle_irq handles all normal device IRQ's (the special 123 * SMP cross-CPU interrupts have their own specific 124 * handlers). 125 */ 126 127 #define MAX_ILLEGAL_IRQS 16 128 129 void 130 handle_irq(int irq) 131 { 132 /* 133 * We ack quickly, we don't want the irq controller 134 * thinking we're snobs just because some other CPU has 135 * disabled global interrupts (we have already done the 136 * INT_ACK cycles, it's too late to try to pretend to the 137 * controller that we aren't taking the interrupt). 138 * 139 * 0 return value means that this irq is already being 140 * handled by some other CPU. (or is disabled) 141 */ 142 static unsigned int illegal_count=0; 143 144 if ((unsigned) irq > ACTUAL_NR_IRQS && illegal_count < MAX_ILLEGAL_IRQS ) { 145 irq_err_count++; 146 illegal_count++; 147 printk(KERN_CRIT "device_interrupt: invalid interrupt %d\n", 148 irq); 149 return; 150 } 151 152 irq_enter(); 153 /* 154 * __do_IRQ() must be called with IPL_MAX. Note that we do not 155 * explicitly enable interrupts afterwards - some MILO PALcode 156 * (namely LX164 one) seems to have severe problems with RTI 157 * at IPL 0. 158 */ 159 local_irq_disable(); 160 __do_IRQ(irq); 161 irq_exit(); 162 } 163