1 /* 2 * linux/kernel/irq/proc.c 3 * 4 * Copyright (C) 1992, 1998-2004 Linus Torvalds, Ingo Molnar 5 * 6 * This file contains the /proc/irq/ handling code. 7 */ 8 9 #include <linux/irq.h> 10 #include <linux/proc_fs.h> 11 #include <linux/interrupt.h> 12 13 #include "internals.h" 14 15 static struct proc_dir_entry *root_irq_dir; 16 17 #ifdef CONFIG_SMP 18 19 static int irq_affinity_read_proc(char *page, char **start, off_t off, 20 int count, int *eof, void *data) 21 { 22 struct irq_desc *desc = irq_desc + (long)data; 23 cpumask_t *mask = &desc->affinity; 24 int len; 25 26 #ifdef CONFIG_GENERIC_PENDING_IRQ 27 if (desc->status & IRQ_MOVE_PENDING) 28 mask = &desc->pending_mask; 29 #endif 30 len = cpumask_scnprintf(page, count, *mask); 31 32 if (count - len < 2) 33 return -EINVAL; 34 len += sprintf(page + len, "\n"); 35 return len; 36 } 37 38 #ifndef is_affinity_mask_valid 39 #define is_affinity_mask_valid(val) 1 40 #endif 41 42 int no_irq_affinity; 43 static int irq_affinity_write_proc(struct file *file, const char __user *buffer, 44 unsigned long count, void *data) 45 { 46 unsigned int irq = (int)(long)data, full_count = count, err; 47 cpumask_t new_value, tmp; 48 49 if (!irq_desc[irq].chip->set_affinity || no_irq_affinity || 50 irq_balancing_disabled(irq)) 51 return -EIO; 52 53 err = cpumask_parse_user(buffer, count, new_value); 54 if (err) 55 return err; 56 57 if (!is_affinity_mask_valid(new_value)) 58 return -EINVAL; 59 60 /* 61 * Do not allow disabling IRQs completely - it's a too easy 62 * way to make the system unusable accidentally :-) At least 63 * one online CPU still has to be targeted. 64 */ 65 cpus_and(tmp, new_value, cpu_online_map); 66 if (cpus_empty(tmp)) 67 /* Special case for empty set - allow the architecture 68 code to set default SMP affinity. */ 69 return select_smp_affinity(irq) ? -EINVAL : full_count; 70 71 irq_set_affinity(irq, new_value); 72 73 return full_count; 74 } 75 76 #endif 77 78 #define MAX_NAMELEN 128 79 80 static int name_unique(unsigned int irq, struct irqaction *new_action) 81 { 82 struct irq_desc *desc = irq_desc + irq; 83 struct irqaction *action; 84 unsigned long flags; 85 int ret = 1; 86 87 spin_lock_irqsave(&desc->lock, flags); 88 for (action = desc->action ; action; action = action->next) { 89 if ((action != new_action) && action->name && 90 !strcmp(new_action->name, action->name)) { 91 ret = 0; 92 break; 93 } 94 } 95 spin_unlock_irqrestore(&desc->lock, flags); 96 return ret; 97 } 98 99 void register_handler_proc(unsigned int irq, struct irqaction *action) 100 { 101 char name [MAX_NAMELEN]; 102 103 if (!irq_desc[irq].dir || action->dir || !action->name || 104 !name_unique(irq, action)) 105 return; 106 107 memset(name, 0, MAX_NAMELEN); 108 snprintf(name, MAX_NAMELEN, "%s", action->name); 109 110 /* create /proc/irq/1234/handler/ */ 111 action->dir = proc_mkdir(name, irq_desc[irq].dir); 112 } 113 114 #undef MAX_NAMELEN 115 116 #define MAX_NAMELEN 10 117 118 void register_irq_proc(unsigned int irq) 119 { 120 char name [MAX_NAMELEN]; 121 122 if (!root_irq_dir || 123 (irq_desc[irq].chip == &no_irq_chip) || 124 irq_desc[irq].dir) 125 return; 126 127 memset(name, 0, MAX_NAMELEN); 128 sprintf(name, "%d", irq); 129 130 /* create /proc/irq/1234 */ 131 irq_desc[irq].dir = proc_mkdir(name, root_irq_dir); 132 133 #ifdef CONFIG_SMP 134 { 135 struct proc_dir_entry *entry; 136 137 /* create /proc/irq/<irq>/smp_affinity */ 138 entry = create_proc_entry("smp_affinity", 0600, irq_desc[irq].dir); 139 140 if (entry) { 141 entry->data = (void *)(long)irq; 142 entry->read_proc = irq_affinity_read_proc; 143 entry->write_proc = irq_affinity_write_proc; 144 } 145 } 146 #endif 147 } 148 149 #undef MAX_NAMELEN 150 151 void unregister_handler_proc(unsigned int irq, struct irqaction *action) 152 { 153 if (action->dir) 154 remove_proc_entry(action->dir->name, irq_desc[irq].dir); 155 } 156 157 void init_irq_proc(void) 158 { 159 int i; 160 161 /* create /proc/irq */ 162 root_irq_dir = proc_mkdir("irq", NULL); 163 if (!root_irq_dir) 164 return; 165 166 /* 167 * Create entries for all existing IRQs. 168 */ 169 for (i = 0; i < NR_IRQS; i++) 170 register_irq_proc(i); 171 } 172 173