linux/kernel/irq/proc.c
Max Krasnyansky 1840475676 genirq: Expose default irq affinity mask (take 3)
Current IRQ affinity interface does not provide a way to set affinity
for the IRQs that will be allocated/activated in the future.
This patch creates /proc/irq/default_smp_affinity that lets users set
default affinity mask for the newly allocated IRQs. Changing the default
does not affect affinity masks for the currently active IRQs, they
have to be changed explicitly.

Updated based on Paul J's comments and added some more documentation.

Signed-off-by: Max Krasnyansky <maxk@qualcomm.com>
Cc: pj@sgi.com
Cc: a.p.zijlstra@chello.nl
Cc: tglx@linutronix.de
Cc: rdunlap@xenotime.net
Cc: mingo@elte.hu
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-06-05 15:18:30 +02:00

240 lines
5.4 KiB
C

/*
* linux/kernel/irq/proc.c
*
* Copyright (C) 1992, 1998-2004 Linus Torvalds, Ingo Molnar
*
* This file contains the /proc/irq/ handling code.
*/
#include <linux/irq.h>
#include <linux/proc_fs.h>
#include <linux/interrupt.h>
#include "internals.h"
static struct proc_dir_entry *root_irq_dir;
#ifdef CONFIG_SMP
static int irq_affinity_read_proc(char *page, char **start, off_t off,
int count, int *eof, void *data)
{
struct irq_desc *desc = irq_desc + (long)data;
cpumask_t *mask = &desc->affinity;
int len;
#ifdef CONFIG_GENERIC_PENDING_IRQ
if (desc->status & IRQ_MOVE_PENDING)
mask = &desc->pending_mask;
#endif
len = cpumask_scnprintf(page, count, *mask);
if (count - len < 2)
return -EINVAL;
len += sprintf(page + len, "\n");
return len;
}
#ifndef is_affinity_mask_valid
#define is_affinity_mask_valid(val) 1
#endif
int no_irq_affinity;
static int irq_affinity_write_proc(struct file *file, const char __user *buffer,
unsigned long count, void *data)
{
unsigned int irq = (int)(long)data, full_count = count, err;
cpumask_t new_value;
if (!irq_desc[irq].chip->set_affinity || no_irq_affinity ||
irq_balancing_disabled(irq))
return -EIO;
err = cpumask_parse_user(buffer, count, new_value);
if (err)
return err;
if (!is_affinity_mask_valid(new_value))
return -EINVAL;
/*
* Do not allow disabling IRQs completely - it's a too easy
* way to make the system unusable accidentally :-) At least
* one online CPU still has to be targeted.
*/
if (!cpus_intersects(new_value, cpu_online_map))
/* Special case for empty set - allow the architecture
code to set default SMP affinity. */
return irq_select_affinity(irq) ? -EINVAL : full_count;
irq_set_affinity(irq, new_value);
return full_count;
}
static int default_affinity_read(char *page, char **start, off_t off,
int count, int *eof, void *data)
{
int len = cpumask_scnprintf(page, count, irq_default_affinity);
if (count - len < 2)
return -EINVAL;
len += sprintf(page + len, "\n");
return len;
}
static int default_affinity_write(struct file *file, const char __user *buffer,
unsigned long count, void *data)
{
unsigned int full_count = count, err;
cpumask_t new_value;
err = cpumask_parse_user(buffer, count, new_value);
if (err)
return err;
if (!is_affinity_mask_valid(new_value))
return -EINVAL;
/*
* Do not allow disabling IRQs completely - it's a too easy
* way to make the system unusable accidentally :-) At least
* one online CPU still has to be targeted.
*/
if (!cpus_intersects(new_value, cpu_online_map))
return -EINVAL;
irq_default_affinity = new_value;
return full_count;
}
#endif
static int irq_spurious_read(char *page, char **start, off_t off,
int count, int *eof, void *data)
{
struct irq_desc *d = &irq_desc[(long) data];
return sprintf(page, "count %u\n"
"unhandled %u\n"
"last_unhandled %u ms\n",
d->irq_count,
d->irqs_unhandled,
jiffies_to_msecs(d->last_unhandled));
}
#define MAX_NAMELEN 128
static int name_unique(unsigned int irq, struct irqaction *new_action)
{
struct irq_desc *desc = irq_desc + irq;
struct irqaction *action;
unsigned long flags;
int ret = 1;
spin_lock_irqsave(&desc->lock, flags);
for (action = desc->action ; action; action = action->next) {
if ((action != new_action) && action->name &&
!strcmp(new_action->name, action->name)) {
ret = 0;
break;
}
}
spin_unlock_irqrestore(&desc->lock, flags);
return ret;
}
void register_handler_proc(unsigned int irq, struct irqaction *action)
{
char name [MAX_NAMELEN];
if (!irq_desc[irq].dir || action->dir || !action->name ||
!name_unique(irq, action))
return;
memset(name, 0, MAX_NAMELEN);
snprintf(name, MAX_NAMELEN, "%s", action->name);
/* create /proc/irq/1234/handler/ */
action->dir = proc_mkdir(name, irq_desc[irq].dir);
}
#undef MAX_NAMELEN
#define MAX_NAMELEN 10
void register_irq_proc(unsigned int irq)
{
char name [MAX_NAMELEN];
struct proc_dir_entry *entry;
if (!root_irq_dir ||
(irq_desc[irq].chip == &no_irq_chip) ||
irq_desc[irq].dir)
return;
memset(name, 0, MAX_NAMELEN);
sprintf(name, "%d", irq);
/* create /proc/irq/1234 */
irq_desc[irq].dir = proc_mkdir(name, root_irq_dir);
#ifdef CONFIG_SMP
{
/* create /proc/irq/<irq>/smp_affinity */
entry = create_proc_entry("smp_affinity", 0600, irq_desc[irq].dir);
if (entry) {
entry->data = (void *)(long)irq;
entry->read_proc = irq_affinity_read_proc;
entry->write_proc = irq_affinity_write_proc;
}
}
#endif
entry = create_proc_entry("spurious", 0444, irq_desc[irq].dir);
if (entry) {
entry->data = (void *)(long)irq;
entry->read_proc = irq_spurious_read;
}
}
#undef MAX_NAMELEN
void unregister_handler_proc(unsigned int irq, struct irqaction *action)
{
if (action->dir)
remove_proc_entry(action->dir->name, irq_desc[irq].dir);
}
void register_default_affinity_proc(void)
{
#ifdef CONFIG_SMP
struct proc_dir_entry *entry;
/* create /proc/irq/default_smp_affinity */
entry = create_proc_entry("default_smp_affinity", 0600, root_irq_dir);
if (entry) {
entry->data = NULL;
entry->read_proc = default_affinity_read;
entry->write_proc = default_affinity_write;
}
#endif
}
void init_irq_proc(void)
{
int i;
/* create /proc/irq */
root_irq_dir = proc_mkdir("irq", NULL);
if (!root_irq_dir)
return;
register_default_affinity_proc();
/*
* Create entries for all existing IRQs.
*/
for (i = 0; i < NR_IRQS; i++)
register_irq_proc(i);
}