https://github.com/torvalds/linux
Tip revision: 6465e260f48790807eef06b583b38ca9789b6072 authored by Linus Torvalds on 24 September 2023, 21:31:13 UTC
Linux 6.6-rc3
Linux 6.6-rc3
Tip revision: 6465e26
proc.c
// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (C) 1992, 1998-2004 Linus Torvalds, Ingo Molnar
*
* This file contains the /proc/irq/ handling code.
*/
#include <linux/irq.h>
#include <linux/gfp.h>
#include <linux/proc_fs.h>
#include <linux/seq_file.h>
#include <linux/interrupt.h>
#include <linux/kernel_stat.h>
#include <linux/mutex.h>
#include "internals.h"
/*
* Access rules:
*
* procfs protects read/write of /proc/irq/N/ files against a
* concurrent free of the interrupt descriptor. remove_proc_entry()
* immediately prevents new read/writes to happen and waits for
* already running read/write functions to complete.
*
* We remove the proc entries first and then delete the interrupt
* descriptor from the radix tree and free it. So it is guaranteed
* that irq_to_desc(N) is valid as long as the read/writes are
* permitted by procfs.
*
* The read from /proc/interrupts is a different problem because there
* is no protection. So the lookup and the access to irqdesc
* information must be protected by sparse_irq_lock.
*/
static struct proc_dir_entry *root_irq_dir;
#ifdef CONFIG_SMP
enum {
AFFINITY,
AFFINITY_LIST,
EFFECTIVE,
EFFECTIVE_LIST,
};
static int show_irq_affinity(int type, struct seq_file *m)
{
struct irq_desc *desc = irq_to_desc((long)m->private);
const struct cpumask *mask;
switch (type) {
case AFFINITY:
case AFFINITY_LIST:
mask = desc->irq_common_data.affinity;
#ifdef CONFIG_GENERIC_PENDING_IRQ
if (irqd_is_setaffinity_pending(&desc->irq_data))
mask = desc->pending_mask;
#endif
break;
case EFFECTIVE:
case EFFECTIVE_LIST:
#ifdef CONFIG_GENERIC_IRQ_EFFECTIVE_AFF_MASK
mask = irq_data_get_effective_affinity_mask(&desc->irq_data);
break;
#endif
default:
return -EINVAL;
}
switch (type) {
case AFFINITY_LIST:
case EFFECTIVE_LIST:
seq_printf(m, "%*pbl\n", cpumask_pr_args(mask));
break;
case AFFINITY:
case EFFECTIVE:
seq_printf(m, "%*pb\n", cpumask_pr_args(mask));
break;
}
return 0;
}
static int irq_affinity_hint_proc_show(struct seq_file *m, void *v)
{
struct irq_desc *desc = irq_to_desc((long)m->private);
unsigned long flags;
cpumask_var_t mask;
if (!zalloc_cpumask_var(&mask, GFP_KERNEL))
return -ENOMEM;
raw_spin_lock_irqsave(&desc->lock, flags);
if (desc->affinity_hint)
cpumask_copy(mask, desc->affinity_hint);
raw_spin_unlock_irqrestore(&desc->lock, flags);
seq_printf(m, "%*pb\n", cpumask_pr_args(mask));
free_cpumask_var(mask);
return 0;
}
int no_irq_affinity;
static int irq_affinity_proc_show(struct seq_file *m, void *v)
{
return show_irq_affinity(AFFINITY, m);
}
static int irq_affinity_list_proc_show(struct seq_file *m, void *v)
{
return show_irq_affinity(AFFINITY_LIST, m);
}
#ifndef CONFIG_AUTO_IRQ_AFFINITY
static inline int irq_select_affinity_usr(unsigned int irq)
{
/*
* If the interrupt is started up already then this fails. The
* interrupt is assigned to an online CPU already. There is no
* point to move it around randomly. Tell user space that the
* selected mask is bogus.
*
* If not then any change to the affinity is pointless because the
* startup code invokes irq_setup_affinity() which will select
* a online CPU anyway.
*/
return -EINVAL;
}
#else
/* ALPHA magic affinity auto selector. Keep it for historical reasons. */
static inline int irq_select_affinity_usr(unsigned int irq)
{
return irq_select_affinity(irq);
}
#endif
static ssize_t write_irq_affinity(int type, struct file *file,
const char __user *buffer, size_t count, loff_t *pos)
{
unsigned int irq = (int)(long)pde_data(file_inode(file));
cpumask_var_t new_value;
int err;
if (!irq_can_set_affinity_usr(irq) || no_irq_affinity)
return -EIO;
if (!zalloc_cpumask_var(&new_value, GFP_KERNEL))
return -ENOMEM;
if (type)
err = cpumask_parselist_user(buffer, count, new_value);
else
err = cpumask_parse_user(buffer, count, new_value);
if (err)
goto free_cpumask;
/*
* 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 (!cpumask_intersects(new_value, cpu_online_mask)) {
/*
* Special case for empty set - allow the architecture code
* to set default SMP affinity.
*/
err = irq_select_affinity_usr(irq) ? -EINVAL : count;
} else {
err = irq_set_affinity(irq, new_value);
if (!err)
err = count;
}
free_cpumask:
free_cpumask_var(new_value);
return err;
}
static ssize_t irq_affinity_proc_write(struct file *file,
const char __user *buffer, size_t count, loff_t *pos)
{
return write_irq_affinity(0, file, buffer, count, pos);
}
static ssize_t irq_affinity_list_proc_write(struct file *file,
const char __user *buffer, size_t count, loff_t *pos)
{
return write_irq_affinity(1, file, buffer, count, pos);
}
static int irq_affinity_proc_open(struct inode *inode, struct file *file)
{
return single_open(file, irq_affinity_proc_show, pde_data(inode));
}
static int irq_affinity_list_proc_open(struct inode *inode, struct file *file)
{
return single_open(file, irq_affinity_list_proc_show, pde_data(inode));
}
static const struct proc_ops irq_affinity_proc_ops = {
.proc_open = irq_affinity_proc_open,
.proc_read = seq_read,
.proc_lseek = seq_lseek,
.proc_release = single_release,
.proc_write = irq_affinity_proc_write,
};
static const struct proc_ops irq_affinity_list_proc_ops = {
.proc_open = irq_affinity_list_proc_open,
.proc_read = seq_read,
.proc_lseek = seq_lseek,
.proc_release = single_release,
.proc_write = irq_affinity_list_proc_write,
};
#ifdef CONFIG_GENERIC_IRQ_EFFECTIVE_AFF_MASK
static int irq_effective_aff_proc_show(struct seq_file *m, void *v)
{
return show_irq_affinity(EFFECTIVE, m);
}
static int irq_effective_aff_list_proc_show(struct seq_file *m, void *v)
{
return show_irq_affinity(EFFECTIVE_LIST, m);
}
#endif
static int default_affinity_show(struct seq_file *m, void *v)
{
seq_printf(m, "%*pb\n", cpumask_pr_args(irq_default_affinity));
return 0;
}
static ssize_t default_affinity_write(struct file *file,
const char __user *buffer, size_t count, loff_t *ppos)
{
cpumask_var_t new_value;
int err;
if (!zalloc_cpumask_var(&new_value, GFP_KERNEL))
return -ENOMEM;
err = cpumask_parse_user(buffer, count, new_value);
if (err)
goto out;
/*
* 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 (!cpumask_intersects(new_value, cpu_online_mask)) {
err = -EINVAL;
goto out;
}
cpumask_copy(irq_default_affinity, new_value);
err = count;
out:
free_cpumask_var(new_value);
return err;
}
static int default_affinity_open(struct inode *inode, struct file *file)
{
return single_open(file, default_affinity_show, pde_data(inode));
}
static const struct proc_ops default_affinity_proc_ops = {
.proc_open = default_affinity_open,
.proc_read = seq_read,
.proc_lseek = seq_lseek,
.proc_release = single_release,
.proc_write = default_affinity_write,
};
static int irq_node_proc_show(struct seq_file *m, void *v)
{
struct irq_desc *desc = irq_to_desc((long) m->private);
seq_printf(m, "%d\n", irq_desc_get_node(desc));
return 0;
}
#endif
static int irq_spurious_proc_show(struct seq_file *m, void *v)
{
struct irq_desc *desc = irq_to_desc((long) m->private);
seq_printf(m, "count %u\n" "unhandled %u\n" "last_unhandled %u ms\n",
desc->irq_count, desc->irqs_unhandled,
jiffies_to_msecs(desc->last_unhandled));
return 0;
}
#define MAX_NAMELEN 128
static int name_unique(unsigned int irq, struct irqaction *new_action)
{
struct irq_desc *desc = irq_to_desc(irq);
struct irqaction *action;
unsigned long flags;
int ret = 1;
raw_spin_lock_irqsave(&desc->lock, flags);
for_each_action_of_desc(desc, action) {
if ((action != new_action) && action->name &&
!strcmp(new_action->name, action->name)) {
ret = 0;
break;
}
}
raw_spin_unlock_irqrestore(&desc->lock, flags);
return ret;
}
void register_handler_proc(unsigned int irq, struct irqaction *action)
{
char name [MAX_NAMELEN];
struct irq_desc *desc = irq_to_desc(irq);
if (!desc->dir || action->dir || !action->name ||
!name_unique(irq, action))
return;
snprintf(name, MAX_NAMELEN, "%s", action->name);
/* create /proc/irq/1234/handler/ */
action->dir = proc_mkdir(name, desc->dir);
}
#undef MAX_NAMELEN
#define MAX_NAMELEN 10
void register_irq_proc(unsigned int irq, struct irq_desc *desc)
{
static DEFINE_MUTEX(register_lock);
void __maybe_unused *irqp = (void *)(unsigned long) irq;
char name [MAX_NAMELEN];
if (!root_irq_dir || (desc->irq_data.chip == &no_irq_chip))
return;
/*
* irq directories are registered only when a handler is
* added, not when the descriptor is created, so multiple
* tasks might try to register at the same time.
*/
mutex_lock(®ister_lock);
if (desc->dir)
goto out_unlock;
sprintf(name, "%d", irq);
/* create /proc/irq/1234 */
desc->dir = proc_mkdir(name, root_irq_dir);
if (!desc->dir)
goto out_unlock;
#ifdef CONFIG_SMP
/* create /proc/irq/<irq>/smp_affinity */
proc_create_data("smp_affinity", 0644, desc->dir,
&irq_affinity_proc_ops, irqp);
/* create /proc/irq/<irq>/affinity_hint */
proc_create_single_data("affinity_hint", 0444, desc->dir,
irq_affinity_hint_proc_show, irqp);
/* create /proc/irq/<irq>/smp_affinity_list */
proc_create_data("smp_affinity_list", 0644, desc->dir,
&irq_affinity_list_proc_ops, irqp);
proc_create_single_data("node", 0444, desc->dir, irq_node_proc_show,
irqp);
# ifdef CONFIG_GENERIC_IRQ_EFFECTIVE_AFF_MASK
proc_create_single_data("effective_affinity", 0444, desc->dir,
irq_effective_aff_proc_show, irqp);
proc_create_single_data("effective_affinity_list", 0444, desc->dir,
irq_effective_aff_list_proc_show, irqp);
# endif
#endif
proc_create_single_data("spurious", 0444, desc->dir,
irq_spurious_proc_show, (void *)(long)irq);
out_unlock:
mutex_unlock(®ister_lock);
}
void unregister_irq_proc(unsigned int irq, struct irq_desc *desc)
{
char name [MAX_NAMELEN];
if (!root_irq_dir || !desc->dir)
return;
#ifdef CONFIG_SMP
remove_proc_entry("smp_affinity", desc->dir);
remove_proc_entry("affinity_hint", desc->dir);
remove_proc_entry("smp_affinity_list", desc->dir);
remove_proc_entry("node", desc->dir);
# ifdef CONFIG_GENERIC_IRQ_EFFECTIVE_AFF_MASK
remove_proc_entry("effective_affinity", desc->dir);
remove_proc_entry("effective_affinity_list", desc->dir);
# endif
#endif
remove_proc_entry("spurious", desc->dir);
sprintf(name, "%u", irq);
remove_proc_entry(name, root_irq_dir);
}
#undef MAX_NAMELEN
void unregister_handler_proc(unsigned int irq, struct irqaction *action)
{
proc_remove(action->dir);
}
static void register_default_affinity_proc(void)
{
#ifdef CONFIG_SMP
proc_create("irq/default_smp_affinity", 0644, NULL,
&default_affinity_proc_ops);
#endif
}
void init_irq_proc(void)
{
unsigned int irq;
struct irq_desc *desc;
/* 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_each_irq_desc(irq, desc)
register_irq_proc(irq, desc);
}
#ifdef CONFIG_GENERIC_IRQ_SHOW
int __weak arch_show_interrupts(struct seq_file *p, int prec)
{
return 0;
}
#ifndef ACTUAL_NR_IRQS
# define ACTUAL_NR_IRQS nr_irqs
#endif
int show_interrupts(struct seq_file *p, void *v)
{
static int prec;
unsigned long flags, any_count = 0;
int i = *(loff_t *) v, j;
struct irqaction *action;
struct irq_desc *desc;
if (i > ACTUAL_NR_IRQS)
return 0;
if (i == ACTUAL_NR_IRQS)
return arch_show_interrupts(p, prec);
/* print header and calculate the width of the first column */
if (i == 0) {
for (prec = 3, j = 1000; prec < 10 && j <= nr_irqs; ++prec)
j *= 10;
seq_printf(p, "%*s", prec + 8, "");
for_each_online_cpu(j)
seq_printf(p, "CPU%-8d", j);
seq_putc(p, '\n');
}
rcu_read_lock();
desc = irq_to_desc(i);
if (!desc || irq_settings_is_hidden(desc))
goto outsparse;
if (desc->kstat_irqs) {
for_each_online_cpu(j)
any_count |= data_race(*per_cpu_ptr(desc->kstat_irqs, j));
}
if ((!desc->action || irq_desc_is_chained(desc)) && !any_count)
goto outsparse;
seq_printf(p, "%*d: ", prec, i);
for_each_online_cpu(j)
seq_printf(p, "%10u ", desc->kstat_irqs ?
*per_cpu_ptr(desc->kstat_irqs, j) : 0);
raw_spin_lock_irqsave(&desc->lock, flags);
if (desc->irq_data.chip) {
if (desc->irq_data.chip->irq_print_chip)
desc->irq_data.chip->irq_print_chip(&desc->irq_data, p);
else if (desc->irq_data.chip->name)
seq_printf(p, " %8s", desc->irq_data.chip->name);
else
seq_printf(p, " %8s", "-");
} else {
seq_printf(p, " %8s", "None");
}
if (desc->irq_data.domain)
seq_printf(p, " %*lu", prec, desc->irq_data.hwirq);
else
seq_printf(p, " %*s", prec, "");
#ifdef CONFIG_GENERIC_IRQ_SHOW_LEVEL
seq_printf(p, " %-8s", irqd_is_level_type(&desc->irq_data) ? "Level" : "Edge");
#endif
if (desc->name)
seq_printf(p, "-%-8s", desc->name);
action = desc->action;
if (action) {
seq_printf(p, " %s", action->name);
while ((action = action->next) != NULL)
seq_printf(p, ", %s", action->name);
}
seq_putc(p, '\n');
raw_spin_unlock_irqrestore(&desc->lock, flags);
outsparse:
rcu_read_unlock();
return 0;
}
#endif