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 <asm/uaccess.h>
  11 #include <linux/profile.h>
  12 #include <linux/proc_fs.h>
  13 #include <linux/seq_file.h>
  14 #include <linux/interrupt.h>
  15
  16 #include "internals.h"
  17
  18 static struct proc_dir_entry *root_irq_dir;
  19
  20 #ifdef CONFIG_SMP
  21
  22 static int irq_affinity_proc_show(struct seq_file *m, void *v)
  23 {
  24         struct irq_desc *desc = irq_to_desc((long)m->private);
  25         const struct cpumask *mask = desc->affinity;
  26
  27 #ifdef CONFIG_GENERIC_PENDING_IRQ
  28         if (desc->status & IRQ_MOVE_PENDING)
  29                 mask = desc->pending_mask;
  30 #endif
  31         seq_cpumask(m, mask);
  32         seq_putc(m, '\n');
  33         return 0;
  34 }
  35
  36 #ifndef is_affinity_mask_valid
  37 #define is_affinity_mask_valid(val) 1
  38 #endif
  39
  40 int no_irq_affinity;
  41 static ssize_t irq_affinity_proc_write(struct file *file,
  42                 const char __user *buffer, size_t count, loff_t *pos)
  43 {
  44         unsigned int irq = (int)(long)PDE(file->f_path.dentry->d_inode)->data;
  45         cpumask_var_t new_value;
  46         int err;
  47
  48         if (!irq_to_desc(irq)->chip->set_affinity || no_irq_affinity ||
  49             irq_balancing_disabled(irq))
  50                 return -EIO;
  51
  52         if (!alloc_cpumask_var(&new_value, GFP_KERNEL))
  53                 return -ENOMEM;
  54
  55         err = cpumask_parse_user(buffer, count, new_value);
  56         if (err)
  57                 goto free_cpumask;
  58
  59         if (!is_affinity_mask_valid(new_value)) {
  60                 err = -EINVAL;
  61                 goto free_cpumask;
  62         }
  63
  64         /*
  65          * Do not allow disabling IRQs completely - it's a too easy
  66          * way to make the system unusable accidentally :-) At least
  67          * one online CPU still has to be targeted.
  68          */
  69         if (!cpumask_intersects(new_value, cpu_online_mask)) {
  70                 /* Special case for empty set - allow the architecture
  71                    code to set default SMP affinity. */
  72                 err = irq_select_affinity_usr(irq) ? -EINVAL : count;
  73         } else {
  74                 irq_set_affinity(irq, new_value);
  75                 err = count;
  76         }
  77
  78 free_cpumask:
  79         free_cpumask_var(new_value);
  80         return err;
  81 }
  82
  83 static int irq_affinity_proc_open(struct inode *inode, struct file *file)
  84 {
  85         return single_open(file, irq_affinity_proc_show, PDE(inode)->data);
  86 }
  87
  88 static const struct file_operations irq_affinity_proc_fops = {
  89         .open           = irq_affinity_proc_open,
  90         .read           = seq_read,
  91         .llseek         = seq_lseek,
  92         .release        = single_release,
  93         .write          = irq_affinity_proc_write,
  94 };
  95
  96 static int default_affinity_show(struct seq_file *m, void *v)
  97 {
  98         seq_cpumask(m, irq_default_affinity);
  99         seq_putc(m, '\n');
 100         return 0;
 101 }
 102
 103 static ssize_t default_affinity_write(struct file *file,
 104                 const char __user *buffer, size_t count, loff_t *ppos)
 105 {
 106         cpumask_var_t new_value;
 107         int err;
 108
 109         if (!alloc_cpumask_var(&new_value, GFP_KERNEL))
 110                 return -ENOMEM;
 111
 112         err = cpumask_parse_user(buffer, count, new_value);
 113         if (err)
 114                 goto out;
 115
 116         if (!is_affinity_mask_valid(new_value)) {
 117                 err = -EINVAL;
 118                 goto out;
 119         }
 120
 121         /* create /proc/irq/prof_cpu_mask */
 122         create_prof_cpu_mask(root_irq_dir);
 123
 124         /*
 125          * Do not allow disabling IRQs completely - it's a too easy
 126          * way to make the system unusable accidentally :-) At least
 127          * one online CPU still has to be targeted.
 128          */
 129         if (!cpumask_intersects(new_value, cpu_online_mask)) {
 130                 err = -EINVAL;
 131                 goto out;
 132         }
 133
 134         cpumask_copy(irq_default_affinity, new_value);
 135         err = count;
 136
 137 out:
 138         free_cpumask_var(new_value);
 139         return err;
 140 }
 141
 142 static int default_affinity_open(struct inode *inode, struct file *file)
 143 {
 144         return single_open(file, default_affinity_show, NULL);
 145 }
 146
 147 static const struct file_operations default_affinity_proc_fops = {
 148         .open           = default_affinity_open,
 149         .read           = seq_read,
 150         .llseek         = seq_lseek,
 151         .release        = single_release,
 152         .write          = default_affinity_write,
 153 };
 154 #endif
 155
 156 static int irq_spurious_read(char *page, char **start, off_t off,
 157                                   int count, int *eof, void *data)
 158 {
 159         struct irq_desc *desc = irq_to_desc((long) data);
 160         return sprintf(page, "count %u\n"
 161                              "unhandled %u\n"
 162                              "last_unhandled %u ms\n",
 163                         desc->irq_count,
 164                         desc->irqs_unhandled,
 165                         jiffies_to_msecs(desc->last_unhandled));
 166 }
 167
 168 #define MAX_NAMELEN 10
 169
 170 void register_irq_proc(unsigned int irq, struct irq_desc *desc)
 171 {
 172         char name [MAX_NAMELEN];
 173         struct proc_dir_entry *entry;
 174
 175         if (!root_irq_dir || (desc->chip == &no_irq_chip) || desc->dir)
 176                 return;
 177
 178         memset(name, 0, MAX_NAMELEN);
 179         sprintf(name, "%d", irq);
 180
 181         /* create /proc/irq/1234 */
 182         desc->dir = proc_mkdir(name, root_irq_dir);
 183
 184 #ifdef CONFIG_SMP
 185         /* create /proc/irq/<irq>/smp_affinity */
 186         proc_create_data("smp_affinity", 0600, desc->dir,
 187                          &irq_affinity_proc_fops, (void *)(long)irq);
 188 #endif
 189
 190         entry = create_proc_entry("spurious", 0444, desc->dir);
 191         if (entry) {
 192                 entry->data = (void *)(long)irq;
 193                 entry->read_proc = irq_spurious_read;
 194         }
 195 }
 196
 197 #undef MAX_NAMELEN
 198
 199 void unregister_handler_proc(unsigned int irq, struct irqaction *action)
 200 {
 201         if (action->threaded)
 202                 remove_proc_entry(action->threaded->name, action->dir);
 203         if (action->dir) {
 204                 struct irq_desc *desc = irq_to_desc(irq);
 205
 206                 remove_proc_entry(action->dir->name, desc->dir);
 207         }
 208 }
 209
 210 static void register_default_affinity_proc(void)
 211 {
 212 #ifdef CONFIG_SMP
 213         proc_create("irq/default_smp_affinity", 0600, NULL,
 214                     &default_affinity_proc_fops);
 215 #endif
 216 }
 217
 218 #ifndef CONFIG_PREEMPT_RT
 219
 220 static int threaded_read_proc(char *page, char **start, off_t off,
 221                               int count, int *eof, void *data)
 222 {
 223         return sprintf(page, "%c\n",
 224                 ((struct irqaction *)data)->flags & IRQF_NODELAY ? '0' : '1');
 225 }
 226
 227 static int threaded_write_proc(struct file *file, const char __user *buffer,
 228                                unsigned long count, void *data)
 229 {
 230         int c;
 231         struct irqaction *action = data;
 232         irq_desc_t *desc = irq_to_desc(action->irq);
 233
 234         if (get_user(c, buffer))
 235                 return -EFAULT;
 236         if (c != '0' && c != '1')
 237                 return -EINVAL;
 238
 239         spin_lock_irq(&desc->lock);
 240
 241         if (c == '0')
 242                 action->flags |= IRQF_NODELAY;
 243         if (c == '1')
 244                 action->flags &= ~IRQF_NODELAY;
 245         recalculate_desc_flags(desc);
 246
 247         spin_unlock_irq(&desc->lock);
 248
 249         return 1;
 250 }
 251
 252 #endif
 253
 254 #define MAX_NAMELEN 128
 255
 256 static int name_unique(unsigned int irq, struct irqaction *new_action)
 257 {
 258         struct irq_desc *desc = irq_to_desc(irq);
 259         struct irqaction *action;
 260
 261         for (action = desc->action ; action; action = action->next)
 262                 if ((action != new_action) && action->name &&
 263                                 !strcmp(new_action->name, action->name))
 264                         return 0;
 265         return 1;
 266 }
 267
 268 void register_handler_proc(unsigned int irq, struct irqaction *action)
 269 {
 270         char name [MAX_NAMELEN];
 271         struct irq_desc *desc = irq_to_desc(irq);
 272
 273         if (!desc->dir || action->dir || !action->name ||
 274                                         !name_unique(irq, action))
 275                 return;
 276
 277         memset(name, 0, MAX_NAMELEN);
 278         snprintf(name, MAX_NAMELEN, "%s", action->name);
 279
 280         /* create /proc/irq/1234/handler/ */
 281         action->dir = proc_mkdir(name, desc->dir);
 282
 283         if (!action->dir)
 284                 return;
 285 #ifndef CONFIG_PREEMPT_RT
 286         {
 287                 struct proc_dir_entry *entry;
 288                 /* create /proc/irq/1234/handler/threaded */
 289                 entry = create_proc_entry("threaded", 0600, action->dir);
 290                 if (!entry)
 291                         return;
 292                 entry->nlink = 1;
 293                 entry->data = (void *)action;
 294                 entry->read_proc = threaded_read_proc;
 295                 entry->write_proc = threaded_write_proc;
 296                 action->threaded = entry;
 297         }
 298 #endif
 299 }
 300
 301 #undef MAX_NAMELEN
 302
 303 void init_irq_proc(void)
 304 {
 305         unsigned int irq;
 306         struct irq_desc *desc;
 307
 308         /* create /proc/irq */
 309         root_irq_dir = proc_mkdir("irq", NULL);
 310         if (!root_irq_dir)
 311                 return;
 312
 313         register_default_affinity_proc();
 314
 315         /*
 316          * Create entries for all existing IRQs.
 317          */
 318         for_each_irq_desc(irq, desc) {
 319                 if (!desc)
 320                         continue;
 321
 322                 register_irq_proc(irq, desc);
 323         }
 324 }
 325