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/gfp.h>
  11 #include <linux/proc_fs.h>
  12 #include <linux/seq_file.h>
  13 #include <linux/interrupt.h>
  14
  15 #include "internals.h"
  16
  17 static struct proc_dir_entry *root_irq_dir;
  18
  19 #ifdef CONFIG_SMP
  20
  21 static int irq_affinity_proc_show(struct seq_file *m, void *v)
  22 {
  23         struct irq_desc *desc = irq_to_desc((long)m->private);
  24         const struct cpumask *mask = desc->affinity;
  25
  26 #ifdef CONFIG_GENERIC_PENDING_IRQ
  27         if (desc->status & IRQ_MOVE_PENDING)
  28                 mask = desc->pending_mask;
  29 #endif
  30         seq_cpumask(m, mask);
  31         seq_putc(m, '\n');
  32         return 0;
  33 }
  34
  35 #ifndef is_affinity_mask_valid
  36 #define is_affinity_mask_valid(val) 1
  37 #endif
  38
  39 int no_irq_affinity;
  40 static ssize_t irq_affinity_proc_write(struct file *file,
  41                 const char __user *buffer, size_t count, loff_t *pos)
  42 {
  43         unsigned int irq = (int)(long)PDE(file->f_path.dentry->d_inode)->data;
  44         cpumask_var_t new_value;
  45         int err;
  46
  47         if (!irq_to_desc(irq)->chip->set_affinity || no_irq_affinity ||
  48             irq_balancing_disabled(irq))
  49                 return -EIO;
  50
  51         if (!alloc_cpumask_var(&new_value, GFP_KERNEL))
  52                 return -ENOMEM;
  53
  54         err = cpumask_parse_user(buffer, count, new_value);
  55         if (err)
  56                 goto free_cpumask;
  57
  58         if (!is_affinity_mask_valid(new_value)) {
  59                 err = -EINVAL;
  60                 goto free_cpumask;
  61         }
  62
  63         /*
  64          * Do not allow disabling IRQs completely - it's a too easy
  65          * way to make the system unusable accidentally :-) At least
  66          * one online CPU still has to be targeted.
  67          */
  68         if (!cpumask_intersects(new_value, cpu_online_mask)) {
  69                 /* Special case for empty set - allow the architecture
  70                    code to set default SMP affinity. */
  71                 err = irq_select_affinity_usr(irq) ? -EINVAL : count;
  72         } else {
  73                 irq_set_affinity(irq, new_value);
  74                 err = count;
  75         }
  76
  77 free_cpumask:
  78         free_cpumask_var(new_value);
  79         return err;
  80 }
  81
  82 static int irq_affinity_proc_open(struct inode *inode, struct file *file)
  83 {
  84         return single_open(file, irq_affinity_proc_show, PDE(inode)->data);
  85 }
  86
  87 static const struct file_operations irq_affinity_proc_fops = {
  88         .open           = irq_affinity_proc_open,
  89         .read           = seq_read,
  90         .llseek         = seq_lseek,
  91         .release        = single_release,
  92         .write          = irq_affinity_proc_write,
  93 };
  94
  95 static int default_affinity_show(struct seq_file *m, void *v)
  96 {
  97         seq_cpumask(m, irq_default_affinity);
  98         seq_putc(m, '\n');
  99         return 0;
 100 }
 101
 102 static ssize_t default_affinity_write(struct file *file,
 103                 const char __user *buffer, size_t count, loff_t *ppos)
 104 {
 105         cpumask_var_t new_value;
 106         int err;
 107
 108         if (!alloc_cpumask_var(&new_value, GFP_KERNEL))
 109                 return -ENOMEM;
 110
 111         err = cpumask_parse_user(buffer, count, new_value);
 112         if (err)
 113                 goto out;
 114
 115         if (!is_affinity_mask_valid(new_value)) {
 116                 err = -EINVAL;
 117                 goto out;
 118         }
 119
 120         /*
 121          * Do not allow disabling IRQs completely - it's a too easy
 122          * way to make the system unusable accidentally :-) At least
 123          * one online CPU still has to be targeted.
 124          */
 125         if (!cpumask_intersects(new_value, cpu_online_mask)) {
 126                 err = -EINVAL;
 127                 goto out;
 128         }
 129
 130         cpumask_copy(irq_default_affinity, new_value);
 131         err = count;
 132
 133 out:
 134         free_cpumask_var(new_value);
 135         return err;
 136 }
 137
 138 static int default_affinity_open(struct inode *inode, struct file *file)
 139 {
 140         return single_open(file, default_affinity_show, PDE(inode)->data);
 141 }
 142
 143 static const struct file_operations default_affinity_proc_fops = {
 144         .open           = default_affinity_open,
 145         .read           = seq_read,
 146         .llseek         = seq_lseek,
 147         .release        = single_release,
 148         .write          = default_affinity_write,
 149 };
 150 #endif
 151
 152 static int irq_spurious_proc_show(struct seq_file *m, void *v)
 153 {
 154         struct irq_desc *desc = irq_to_desc((long) m->private);
 155
 156         seq_printf(m, "count %u\n" "unhandled %u\n" "last_unhandled %u ms\n",
 157                    desc->irq_count, desc->irqs_unhandled,
 158                    jiffies_to_msecs(desc->last_unhandled));
 159         return 0;
 160 }
 161
 162 static int irq_spurious_proc_open(struct inode *inode, struct file *file)
 163 {
 164         return single_open(file, irq_spurious_proc_show, NULL);
 165 }
 166
 167 static const struct file_operations irq_spurious_proc_fops = {
 168         .open           = irq_spurious_proc_open,
 169         .read           = seq_read,
 170         .llseek         = seq_lseek,
 171         .release        = single_release,
 172 };
 173
 174 #define MAX_NAMELEN 128
 175
 176 static int name_unique(unsigned int irq, struct irqaction *new_action)
 177 {
 178         struct irq_desc *desc = irq_to_desc(irq);
 179         struct irqaction *action;
 180         unsigned long flags;
 181         int ret = 1;
 182
 183         raw_spin_lock_irqsave(&desc->lock, flags);
 184         for (action = desc->action ; action; action = action->next) {
 185                 if ((action != new_action) && action->name &&
 186                                 !strcmp(new_action->name, action->name)) {
 187                         ret = 0;
 188                         break;
 189                 }
 190         }
 191         raw_spin_unlock_irqrestore(&desc->lock, flags);
 192         return ret;
 193 }
 194
 195 void register_handler_proc(unsigned int irq, struct irqaction *action)
 196 {
 197         char name [MAX_NAMELEN];
 198         struct irq_desc *desc = irq_to_desc(irq);
 199
 200         if (!desc->dir || action->dir || !action->name ||
 201                                         !name_unique(irq, action))
 202                 return;
 203
 204         memset(name, 0, MAX_NAMELEN);
 205         snprintf(name, MAX_NAMELEN, "%s", action->name);
 206
 207         /* create /proc/irq/1234/handler/ */
 208         action->dir = proc_mkdir(name, desc->dir);
 209 }
 210
 211 #undef MAX_NAMELEN
 212
 213 #define MAX_NAMELEN 10
 214
 215 void register_irq_proc(unsigned int irq, struct irq_desc *desc)
 216 {
 217         char name [MAX_NAMELEN];
 218
 219         if (!root_irq_dir || (desc->chip == &no_irq_chip) || desc->dir)
 220                 return;
 221
 222         memset(name, 0, MAX_NAMELEN);
 223         sprintf(name, "%d", irq);
 224
 225         /* create /proc/irq/1234 */
 226         desc->dir = proc_mkdir(name, root_irq_dir);
 227         if (!desc->dir)
 228                 return;
 229
 230 #ifdef CONFIG_SMP
 231         /* create /proc/irq/<irq>/smp_affinity */
 232         proc_create_data("smp_affinity", 0600, desc->dir,
 233                          &irq_affinity_proc_fops, (void *)(long)irq);
 234 #endif
 235
 236         proc_create_data("spurious", 0444, desc->dir,
 237                          &irq_spurious_proc_fops, (void *)(long)irq);
 238 }
 239
 240 #undef MAX_NAMELEN
 241
 242 void unregister_handler_proc(unsigned int irq, struct irqaction *action)
 243 {
 244         if (action->dir) {
 245                 struct irq_desc *desc = irq_to_desc(irq);
 246
 247                 remove_proc_entry(action->dir->name, desc->dir);
 248         }
 249 }
 250
 251 static void register_default_affinity_proc(void)
 252 {
 253 #ifdef CONFIG_SMP
 254         proc_create("irq/default_smp_affinity", 0600, NULL,
 255                     &default_affinity_proc_fops);
 256 #endif
 257 }
 258
 259 void init_irq_proc(void)
 260 {
 261         unsigned int irq;
 262         struct irq_desc *desc;
 263
 264         /* create /proc/irq */
 265         root_irq_dir = proc_mkdir("irq", NULL);
 266         if (!root_irq_dir)
 267                 return;
 268
 269         register_default_affinity_proc();
 270
 271         /*
 272          * Create entries for all existing IRQs.
 273          */
 274         for_each_irq_desc(irq, desc) {
 275                 if (!desc)
 276                         continue;
 277
 278                 register_irq_proc(irq, desc);
 279         }
 280 }
 281