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;
  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         if (!cpus_intersects(new_value, cpu_online_map))
  66                 /* Special case for empty set - allow the architecture
  67                    code to set default SMP affinity. */
  68                 return irq_select_affinity(irq) ? -EINVAL : full_count;
  69
  70         irq_set_affinity(irq, new_value);
  71
  72         return full_count;
  73 }
  74
  75 static int default_affinity_read(char *page, char **start, off_t off,
  76                                   int count, int *eof, void *data)
  77 {
  78         int len = cpumask_scnprintf(page, count, irq_default_affinity);
  79         if (count - len < 2)
  80                 return -EINVAL;
  81         len += sprintf(page + len, "\n");
  82         return len;
  83 }
  84
  85 static int default_affinity_write(struct file *file, const char __user *buffer,
  86                                    unsigned long count, void *data)
  87 {
  88         unsigned int full_count = count, err;
  89         cpumask_t new_value;
  90
  91         err = cpumask_parse_user(buffer, count, new_value);
  92         if (err)
  93                 return err;
  94
  95         if (!is_affinity_mask_valid(new_value))
  96                 return -EINVAL;
  97
  98         /*
  99          * Do not allow disabling IRQs completely - it's a too easy
 100          * way to make the system unusable accidentally :-) At least
 101          * one online CPU still has to be targeted.
 102          */
 103         if (!cpus_intersects(new_value, cpu_online_map))
 104                 return -EINVAL;
 105
 106         irq_default_affinity = new_value;
 107
 108         return full_count;
 109 }
 110 #endif
 111
 112 static int irq_spurious_read(char *page, char **start, off_t off,
 113                                   int count, int *eof, void *data)
 114 {
 115         struct irq_desc *d = &irq_desc[(long) data];
 116         return sprintf(page, "count %u\n"
 117                              "unhandled %u\n"
 118                              "last_unhandled %u ms\n",
 119                         d->irq_count,
 120                         d->irqs_unhandled,
 121                         jiffies_to_msecs(d->last_unhandled));
 122 }
 123
 124 #define MAX_NAMELEN 128
 125
 126 static int name_unique(unsigned int irq, struct irqaction *new_action)
 127 {
 128         struct irq_desc *desc = irq_desc + irq;
 129         struct irqaction *action;
 130         unsigned long flags;
 131         int ret = 1;
 132
 133         spin_lock_irqsave(&desc->lock, flags);
 134         for (action = desc->action ; action; action = action->next) {
 135                 if ((action != new_action) && action->name &&
 136                                 !strcmp(new_action->name, action->name)) {
 137                         ret = 0;
 138                         break;
 139                 }
 140         }
 141         spin_unlock_irqrestore(&desc->lock, flags);
 142         return ret;
 143 }
 144
 145 void register_handler_proc(unsigned int irq, struct irqaction *action)
 146 {
 147         char name [MAX_NAMELEN];
 148
 149         if (!irq_desc[irq].dir || action->dir || !action->name ||
 150                                         !name_unique(irq, action))
 151                 return;
 152
 153         memset(name, 0, MAX_NAMELEN);
 154         snprintf(name, MAX_NAMELEN, "%s", action->name);
 155
 156         /* create /proc/irq/1234/handler/ */
 157         action->dir = proc_mkdir(name, irq_desc[irq].dir);
 158 }
 159
 160 #undef MAX_NAMELEN
 161
 162 #define MAX_NAMELEN 10
 163
 164 void register_irq_proc(unsigned int irq)
 165 {
 166         char name [MAX_NAMELEN];
 167         struct proc_dir_entry *entry;
 168
 169         if (!root_irq_dir ||
 170                 (irq_desc[irq].chip == &no_irq_chip) ||
 171                         irq_desc[irq].dir)
 172                 return;
 173
 174         memset(name, 0, MAX_NAMELEN);
 175         sprintf(name, "%d", irq);
 176
 177         /* create /proc/irq/1234 */
 178         irq_desc[irq].dir = proc_mkdir(name, root_irq_dir);
 179
 180 #ifdef CONFIG_SMP
 181         {
 182                 /* create /proc/irq/<irq>/smp_affinity */
 183                 entry = create_proc_entry("smp_affinity", 0600, irq_desc[irq].dir);
 184
 185                 if (entry) {
 186                         entry->data = (void *)(long)irq;
 187                         entry->read_proc = irq_affinity_read_proc;
 188                         entry->write_proc = irq_affinity_write_proc;
 189                 }
 190         }
 191 #endif
 192
 193         entry = create_proc_entry("spurious", 0444, irq_desc[irq].dir);
 194         if (entry) {
 195                 entry->data = (void *)(long)irq;
 196                 entry->read_proc = irq_spurious_read;
 197         }
 198 }
 199
 200 #undef MAX_NAMELEN
 201
 202 void unregister_handler_proc(unsigned int irq, struct irqaction *action)
 203 {
 204         if (action->dir)
 205                 remove_proc_entry(action->dir->name, irq_desc[irq].dir);
 206 }
 207
 208 void register_default_affinity_proc(void)
 209 {
 210 #ifdef CONFIG_SMP
 211         struct proc_dir_entry *entry;
 212
 213         /* create /proc/irq/default_smp_affinity */
 214         entry = create_proc_entry("default_smp_affinity", 0600, root_irq_dir);
 215         if (entry) {
 216                 entry->data = NULL;
 217                 entry->read_proc  = default_affinity_read;
 218                 entry->write_proc = default_affinity_write;
 219         }
 220 #endif
 221 }
 222
 223 void init_irq_proc(void)
 224 {
 225         int i;
 226
 227         /* create /proc/irq */
 228         root_irq_dir = proc_mkdir("irq", NULL);
 229         if (!root_irq_dir)
 230                 return;
 231
 232         register_default_affinity_proc();
 233
 234         /*
 235          * Create entries for all existing IRQs.
 236          */
 237         for (i = 0; i < NR_IRQS; i++)
 238                 register_irq_proc(i);
 239 }
 240