kernel/irq/proc.c

   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 static int irq_spurious_read(char *page, char **start, off_t off,
  79                                   int count, int *eof, void *data)
  80 {
  81         struct irq_desc *d = &irq_desc[(long) data];
  82         return sprintf(page, "count %u\n"
  83                              "unhandled %u\n"
  84                              "last_unhandled %u ms\n",
  85                         d->irq_count,
  86                         d->irqs_unhandled,
  87                         jiffies_to_msecs(d->last_unhandled));
  88 }
  89
  90 #define MAX_NAMELEN 128
  91
  92 static int name_unique(unsigned int irq, struct irqaction *new_action)
  93 {
  94         struct irq_desc *desc = irq_desc + irq;
  95         struct irqaction *action;
  96         unsigned long flags;
  97         int ret = 1;
  98
  99         spin_lock_irqsave(&desc->lock, flags);
 100         for (action = desc->action ; action; action = action->next) {
 101                 if ((action != new_action) && action->name &&
 102                                 !strcmp(new_action->name, action->name)) {
 103                         ret = 0;
 104                         break;
 105                 }
 106         }
 107         spin_unlock_irqrestore(&desc->lock, flags);
 108         return ret;
 109 }
 110
 111 void register_handler_proc(unsigned int irq, struct irqaction *action)
 112 {
 113         char name [MAX_NAMELEN];
 114
 115         if (!irq_desc[irq].dir || action->dir || !action->name ||
 116                                         !name_unique(irq, action))
 117                 return;
 118
 119         memset(name, 0, MAX_NAMELEN);
 120         snprintf(name, MAX_NAMELEN, "%s", action->name);
 121
 122         /* create /proc/irq/1234/handler/ */
 123         action->dir = proc_mkdir(name, irq_desc[irq].dir);
 124 }
 125
 126 #undef MAX_NAMELEN
 127
 128 #define MAX_NAMELEN 10
 129
 130 void register_irq_proc(unsigned int irq)
 131 {
 132         char name [MAX_NAMELEN];
 133         struct proc_dir_entry *entry;
 134
 135         if (!root_irq_dir ||
 136                 (irq_desc[irq].chip == &no_irq_chip) ||
 137                         irq_desc[irq].dir)
 138                 return;
 139
 140         memset(name, 0, MAX_NAMELEN);
 141         sprintf(name, "%d", irq);
 142
 143         /* create /proc/irq/1234 */
 144         irq_desc[irq].dir = proc_mkdir(name, root_irq_dir);
 145
 146 #ifdef CONFIG_SMP
 147         {
 148                 /* create /proc/irq/<irq>/smp_affinity */
 149                 entry = create_proc_entry("smp_affinity", 0600, irq_desc[irq].dir);
 150
 151                 if (entry) {
 152                         entry->data = (void *)(long)irq;
 153                         entry->read_proc = irq_affinity_read_proc;
 154                         entry->write_proc = irq_affinity_write_proc;
 155                 }
 156         }
 157 #endif
 158
 159         entry = create_proc_entry("spurious", 0444, irq_desc[irq].dir);
 160         if (entry) {
 161                 entry->data = (void *)(long)irq;
 162                 entry->read_proc = irq_spurious_read;
 163         }
 164 }
 165
 166 #undef MAX_NAMELEN
 167
 168 void unregister_handler_proc(unsigned int irq, struct irqaction *action)
 169 {
 170         if (action->dir)
 171                 remove_proc_entry(action->dir->name, irq_desc[irq].dir);
 172 }
 173
 174 void init_irq_proc(void)
 175 {
 176         int i;
 177
 178         /* create /proc/irq */
 179         root_irq_dir = proc_mkdir("irq", NULL);
 180         if (!root_irq_dir)
 181                 return;
 182
 183         /*
 184          * Create entries for all existing IRQs.
 185          */
 186         for (i = 0; i < NR_IRQS; i++)
 187                 register_irq_proc(i);
 188 }
 189