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/config.h> 14 #include <linux/kernel.h> 15 #include <linux/module.h> 16 #include <linux/errno.h> 17 #include <linux/kernel_stat.h> 18 #include <linux/signal.h> 19 #include <linux/sched.h> 20 #include <linux/ptrace.h> 21 #include <linux/interrupt.h> 22 #include <linux/slab.h> 23 #include <linux/random.h> 24 #include <linux/init.h> 25 #include <linux/irq.h> 26 #include <linux/proc_fs.h> 27 #include <linux/seq_file.h> 28 #include <linux/profile.h> 29 #include <linux/bitops.h> 30 31 #include <asm/system.h> 32 #include <asm/io.h> 33 #include <asm/uaccess.h> 34 35 volatile unsigned long irq_err_count; 36 37 void ack_bad_irq(unsigned int irq) 38 { 39 irq_err_count++; 40 printk(KERN_CRIT "Unexpected IRQ trap at vector %u\n", irq); 41 } 42 43 #ifdef CONFIG_SMP 44 static char irq_user_affinity[NR_IRQS]; 45 46 int 47 select_smp_affinity(unsigned int irq) 48 { 49 static int last_cpu; 50 int cpu = last_cpu + 1; 51 52 if (!irq_desc[irq].handler->set_affinity || irq_user_affinity[irq]) 53 return 1; 54 55 while (!cpu_possible(cpu)) 56 cpu = (cpu < (NR_CPUS-1) ? cpu + 1 : 0); 57 last_cpu = cpu; 58 59 irq_affinity[irq] = cpumask_of_cpu(cpu); 60 irq_desc[irq].handler->set_affinity(irq, cpumask_of_cpu(cpu)); 61 return 0; 62 } 63 #endif /* CONFIG_SMP */ 64 65 int 66 show_interrupts(struct seq_file *p, void *v) 67 { 68 #ifdef CONFIG_SMP 69 int j; 70 #endif 71 int irq = *(loff_t *) v; 72 struct irqaction * action; 73 unsigned long flags; 74 75 #ifdef CONFIG_SMP 76 if (irq == 0) { 77 seq_puts(p, " "); 78 for_each_online_cpu(j) 79 seq_printf(p, "CPU%d ", j); 80 seq_putc(p, '\n'); 81 } 82 #endif 83 84 if (irq < ACTUAL_NR_IRQS) { 85 spin_lock_irqsave(&irq_desc[irq].lock, flags); 86 action = irq_desc[irq].action; 87 if (!action) 88 goto unlock; 89 seq_printf(p, "%3d: ", irq); 90 #ifndef CONFIG_SMP 91 seq_printf(p, "%10u ", kstat_irqs(irq)); 92 #else 93 for_each_online_cpu(j) 94 seq_printf(p, "%10u ", kstat_cpu(j).irqs[irq]); 95 #endif 96 seq_printf(p, " %14s", irq_desc[irq].handler->typename); 97 seq_printf(p, " %c%s", 98 (action->flags & SA_INTERRUPT)?'+':' ', 99 action->name); 100 101 for (action=action->next; action; action = action->next) { 102 seq_printf(p, ", %c%s", 103 (action->flags & SA_INTERRUPT)?'+':' ', 104 action->name); 105 } 106 107 seq_putc(p, '\n'); 108 unlock: 109 spin_unlock_irqrestore(&irq_desc[irq].lock, flags); 110 } else if (irq == ACTUAL_NR_IRQS) { 111 #ifdef CONFIG_SMP 112 seq_puts(p, "IPI: "); 113 for_each_online_cpu(j) 114 seq_printf(p, "%10lu ", cpu_data[j].ipi_count); 115 seq_putc(p, '\n'); 116 #endif 117 seq_printf(p, "ERR: %10lu\n", irq_err_count); 118 } 119 return 0; 120 } 121 122 /* 123 * handle_irq handles all normal device IRQ's (the special 124 * SMP cross-CPU interrupts have their own specific 125 * handlers). 126 */ 127 128 #define MAX_ILLEGAL_IRQS 16 129 130 void 131 handle_irq(int irq, struct pt_regs * regs) 132 { 133 /* 134 * We ack quickly, we don't want the irq controller 135 * thinking we're snobs just because some other CPU has 136 * disabled global interrupts (we have already done the 137 * INT_ACK cycles, it's too late to try to pretend to the 138 * controller that we aren't taking the interrupt). 139 * 140 * 0 return value means that this irq is already being 141 * handled by some other CPU. (or is disabled) 142 */ 143 static unsigned int illegal_count=0; 144 145 if ((unsigned) irq > ACTUAL_NR_IRQS && illegal_count < MAX_ILLEGAL_IRQS ) { 146 irq_err_count++; 147 illegal_count++; 148 printk(KERN_CRIT "device_interrupt: invalid interrupt %d\n", 149 irq); 150 return; 151 } 152 153 irq_enter(); 154 /* 155 * __do_IRQ() must be called with IPL_MAX. Note that we do not 156 * explicitly enable interrupts afterwards - some MILO PALcode 157 * (namely LX164 one) seems to have severe problems with RTI 158 * at IPL 0. 159 */ 160 local_irq_disable(); 161 __do_IRQ(irq, regs); 162 irq_exit(); 163 } 164