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 #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