linux/kernel/irq/debugfs.c
Marc Zyngier 536e2e34bd genirq/debugfs: Triggering of interrupts from userspace
When developing new (and therefore buggy) interrupt related
code, it can sometimes be useful to inject interrupts without
having to rely on a device to actually generate them.

This functionnality relies either on the irqchip driver to
expose a irq_set_irqchip_state(IRQCHIP_STATE_PENDING) callback,
or on the core code to be able to retrigger a (edge-only)
interrupt.

To use this feature:

echo -n trigger > /sys/kernel/debug/irq/irqs/IRQNUM

WARNING: This is DANGEROUS, and strictly a debug feature.
Do not use it on a production system. Your HW is likely to
catch fire, your data to be corrupted, and reporting this will
make you look an even bigger fool than the idiot who wrote
this patch.

Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20170818081156.9264-1-marc.zyngier@arm.com
2017-08-18 10:36:24 +02:00

262 lines
6.8 KiB
C

/*
* Copyright 2017 Thomas Gleixner <tglx@linutronix.de>
*
* This file is licensed under the GPL V2.
*/
#include <linux/irqdomain.h>
#include <linux/irq.h>
#include <linux/uaccess.h>
#include "internals.h"
static struct dentry *irq_dir;
struct irq_bit_descr {
unsigned int mask;
char *name;
};
#define BIT_MASK_DESCR(m) { .mask = m, .name = #m }
static void irq_debug_show_bits(struct seq_file *m, int ind, unsigned int state,
const struct irq_bit_descr *sd, int size)
{
int i;
for (i = 0; i < size; i++, sd++) {
if (state & sd->mask)
seq_printf(m, "%*s%s\n", ind + 12, "", sd->name);
}
}
#ifdef CONFIG_SMP
static void irq_debug_show_masks(struct seq_file *m, struct irq_desc *desc)
{
struct irq_data *data = irq_desc_get_irq_data(desc);
struct cpumask *msk;
msk = irq_data_get_affinity_mask(data);
seq_printf(m, "affinity: %*pbl\n", cpumask_pr_args(msk));
#ifdef CONFIG_GENERIC_IRQ_EFFECTIVE_AFF_MASK
msk = irq_data_get_effective_affinity_mask(data);
seq_printf(m, "effectiv: %*pbl\n", cpumask_pr_args(msk));
#endif
#ifdef CONFIG_GENERIC_PENDING_IRQ
msk = desc->pending_mask;
seq_printf(m, "pending: %*pbl\n", cpumask_pr_args(msk));
#endif
}
#else
static void irq_debug_show_masks(struct seq_file *m, struct irq_desc *desc) { }
#endif
static const struct irq_bit_descr irqchip_flags[] = {
BIT_MASK_DESCR(IRQCHIP_SET_TYPE_MASKED),
BIT_MASK_DESCR(IRQCHIP_EOI_IF_HANDLED),
BIT_MASK_DESCR(IRQCHIP_MASK_ON_SUSPEND),
BIT_MASK_DESCR(IRQCHIP_ONOFFLINE_ENABLED),
BIT_MASK_DESCR(IRQCHIP_SKIP_SET_WAKE),
BIT_MASK_DESCR(IRQCHIP_ONESHOT_SAFE),
BIT_MASK_DESCR(IRQCHIP_EOI_THREADED),
};
static void
irq_debug_show_chip(struct seq_file *m, struct irq_data *data, int ind)
{
struct irq_chip *chip = data->chip;
if (!chip) {
seq_printf(m, "chip: None\n");
return;
}
seq_printf(m, "%*schip: %s\n", ind, "", chip->name);
seq_printf(m, "%*sflags: 0x%lx\n", ind + 1, "", chip->flags);
irq_debug_show_bits(m, ind, chip->flags, irqchip_flags,
ARRAY_SIZE(irqchip_flags));
}
static void
irq_debug_show_data(struct seq_file *m, struct irq_data *data, int ind)
{
seq_printf(m, "%*sdomain: %s\n", ind, "",
data->domain ? data->domain->name : "");
seq_printf(m, "%*shwirq: 0x%lx\n", ind + 1, "", data->hwirq);
irq_debug_show_chip(m, data, ind + 1);
#ifdef CONFIG_IRQ_DOMAIN_HIERARCHY
if (!data->parent_data)
return;
seq_printf(m, "%*sparent:\n", ind + 1, "");
irq_debug_show_data(m, data->parent_data, ind + 4);
#endif
}
static const struct irq_bit_descr irqdata_states[] = {
BIT_MASK_DESCR(IRQ_TYPE_EDGE_RISING),
BIT_MASK_DESCR(IRQ_TYPE_EDGE_FALLING),
BIT_MASK_DESCR(IRQ_TYPE_LEVEL_HIGH),
BIT_MASK_DESCR(IRQ_TYPE_LEVEL_LOW),
BIT_MASK_DESCR(IRQD_LEVEL),
BIT_MASK_DESCR(IRQD_ACTIVATED),
BIT_MASK_DESCR(IRQD_IRQ_STARTED),
BIT_MASK_DESCR(IRQD_IRQ_DISABLED),
BIT_MASK_DESCR(IRQD_IRQ_MASKED),
BIT_MASK_DESCR(IRQD_IRQ_INPROGRESS),
BIT_MASK_DESCR(IRQD_PER_CPU),
BIT_MASK_DESCR(IRQD_NO_BALANCING),
BIT_MASK_DESCR(IRQD_SINGLE_TARGET),
BIT_MASK_DESCR(IRQD_MOVE_PCNTXT),
BIT_MASK_DESCR(IRQD_AFFINITY_SET),
BIT_MASK_DESCR(IRQD_SETAFFINITY_PENDING),
BIT_MASK_DESCR(IRQD_AFFINITY_MANAGED),
BIT_MASK_DESCR(IRQD_MANAGED_SHUTDOWN),
BIT_MASK_DESCR(IRQD_FORWARDED_TO_VCPU),
BIT_MASK_DESCR(IRQD_WAKEUP_STATE),
BIT_MASK_DESCR(IRQD_WAKEUP_ARMED),
};
static const struct irq_bit_descr irqdesc_states[] = {
BIT_MASK_DESCR(_IRQ_NOPROBE),
BIT_MASK_DESCR(_IRQ_NOREQUEST),
BIT_MASK_DESCR(_IRQ_NOTHREAD),
BIT_MASK_DESCR(_IRQ_NOAUTOEN),
BIT_MASK_DESCR(_IRQ_NESTED_THREAD),
BIT_MASK_DESCR(_IRQ_PER_CPU_DEVID),
BIT_MASK_DESCR(_IRQ_IS_POLLED),
BIT_MASK_DESCR(_IRQ_DISABLE_UNLAZY),
};
static const struct irq_bit_descr irqdesc_istates[] = {
BIT_MASK_DESCR(IRQS_AUTODETECT),
BIT_MASK_DESCR(IRQS_SPURIOUS_DISABLED),
BIT_MASK_DESCR(IRQS_POLL_INPROGRESS),
BIT_MASK_DESCR(IRQS_ONESHOT),
BIT_MASK_DESCR(IRQS_REPLAY),
BIT_MASK_DESCR(IRQS_WAITING),
BIT_MASK_DESCR(IRQS_PENDING),
BIT_MASK_DESCR(IRQS_SUSPENDED),
};
static int irq_debug_show(struct seq_file *m, void *p)
{
struct irq_desc *desc = m->private;
struct irq_data *data;
raw_spin_lock_irq(&desc->lock);
data = irq_desc_get_irq_data(desc);
seq_printf(m, "handler: %pf\n", desc->handle_irq);
seq_printf(m, "status: 0x%08x\n", desc->status_use_accessors);
irq_debug_show_bits(m, 0, desc->status_use_accessors, irqdesc_states,
ARRAY_SIZE(irqdesc_states));
seq_printf(m, "istate: 0x%08x\n", desc->istate);
irq_debug_show_bits(m, 0, desc->istate, irqdesc_istates,
ARRAY_SIZE(irqdesc_istates));
seq_printf(m, "ddepth: %u\n", desc->depth);
seq_printf(m, "wdepth: %u\n", desc->wake_depth);
seq_printf(m, "dstate: 0x%08x\n", irqd_get(data));
irq_debug_show_bits(m, 0, irqd_get(data), irqdata_states,
ARRAY_SIZE(irqdata_states));
seq_printf(m, "node: %d\n", irq_data_get_node(data));
irq_debug_show_masks(m, desc);
irq_debug_show_data(m, data, 0);
raw_spin_unlock_irq(&desc->lock);
return 0;
}
static int irq_debug_open(struct inode *inode, struct file *file)
{
return single_open(file, irq_debug_show, inode->i_private);
}
static ssize_t irq_debug_write(struct file *file, const char __user *user_buf,
size_t count, loff_t *ppos)
{
struct irq_desc *desc = file_inode(file)->i_private;
char buf[8] = { 0, };
size_t size;
size = min(sizeof(buf) - 1, count);
if (copy_from_user(buf, user_buf, size))
return -EFAULT;
if (!strncmp(buf, "trigger", size)) {
unsigned long flags;
int err;
/* Try the HW interface first */
err = irq_set_irqchip_state(irq_desc_get_irq(desc),
IRQCHIP_STATE_PENDING, true);
if (!err)
return count;
/*
* Otherwise, try to inject via the resend interface,
* which may or may not succeed.
*/
chip_bus_lock(desc);
raw_spin_lock_irqsave(&desc->lock, flags);
if (irq_settings_is_level(desc)) {
/* Can't do level, sorry */
err = -EINVAL;
} else {
desc->istate |= IRQS_PENDING;
check_irq_resend(desc);
err = 0;
}
raw_spin_unlock_irqrestore(&desc->lock, flags);
chip_bus_sync_unlock(desc);
return err ? err : count;
}
return count;
}
static const struct file_operations dfs_irq_ops = {
.open = irq_debug_open,
.write = irq_debug_write,
.read = seq_read,
.llseek = seq_lseek,
.release = single_release,
};
void irq_add_debugfs_entry(unsigned int irq, struct irq_desc *desc)
{
char name [10];
if (!irq_dir || !desc || desc->debugfs_file)
return;
sprintf(name, "%d", irq);
desc->debugfs_file = debugfs_create_file(name, 0644, irq_dir, desc,
&dfs_irq_ops);
}
static int __init irq_debugfs_init(void)
{
struct dentry *root_dir;
int irq;
root_dir = debugfs_create_dir("irq", NULL);
if (!root_dir)
return -ENOMEM;
irq_domain_debugfs_init(root_dir);
irq_dir = debugfs_create_dir("irqs", root_dir);
irq_lock_sparse();
for_each_active_irq(irq)
irq_add_debugfs_entry(irq, irq_to_desc(irq));
irq_unlock_sparse();
return 0;
}
__initcall(irq_debugfs_init);