genirq/debugfs: Add proper debugfs interface
Debugging (hierarchical) interupt domains is tedious as there is no
information about the hierarchy and no information about states of
interrupts in the various domain levels.
Add a debugfs directory 'irq' and subdirectories 'domains' and 'irqs'.
The domains directory contains the domain files. The content is information
about the domain. If the domain is part of a hierarchy then the parent
domains are printed as well.
# ls /sys/kernel/debug/irq/domains/
default INTEL-IR-2 INTEL-IR-MSI-2 IO-APIC-IR-2 PCI-MSI
DMAR-MSI INTEL-IR-3 INTEL-IR-MSI-3 IO-APIC-IR-3 unknown-1
INTEL-IR-0 INTEL-IR-MSI-0 IO-APIC-IR-0 IO-APIC-IR-4 VECTOR
INTEL-IR-1 INTEL-IR-MSI-1 IO-APIC-IR-1 PCI-HT
# cat /sys/kernel/debug/irq/domains/VECTOR
name: VECTOR
size: 0
mapped: 216
flags: 0x00000041
# cat /sys/kernel/debug/irq/domains/IO-APIC-IR-0
name: IO-APIC-IR-0
size: 24
mapped: 19
flags: 0x00000041
parent: INTEL-IR-3
name: INTEL-IR-3
size: 65536
mapped: 167
flags: 0x00000041
parent: VECTOR
name: VECTOR
size: 0
mapped: 216
flags: 0x00000041
Unfortunately there is no per cpu information about the VECTOR domain (yet).
The irqs directory contains detailed information about mapped interrupts.
# cat /sys/kernel/debug/irq/irqs/3
handler: handle_edge_irq
status: 0x00004000
istate: 0x00000000
ddepth: 1
wdepth: 0
dstate: 0x01018000
IRQD_IRQ_DISABLED
IRQD_SINGLE_TARGET
IRQD_MOVE_PCNTXT
node: 0
affinity: 0-143
effectiv: 0
pending:
domain: IO-APIC-IR-0
hwirq: 0x3
chip: IR-IO-APIC
flags: 0x10
IRQCHIP_SKIP_SET_WAKE
parent:
domain: INTEL-IR-3
hwirq: 0x20000
chip: INTEL-IR
flags: 0x0
parent:
domain: VECTOR
hwirq: 0x3
chip: APIC
flags: 0x0
This was developed to simplify the debugging of the managed affinity
changes.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Marc Zyngier <marc.zyngier@arm.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Keith Busch <keith.busch@intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Christoph Hellwig <hch@lst.de>
Link: http://lkml.kernel.org/r/20170619235444.537566163@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
diff --git a/kernel/irq/Kconfig b/kernel/irq/Kconfig
index 3bbfd6a..8d9498e 100644
--- a/kernel/irq/Kconfig
+++ b/kernel/irq/Kconfig
@@ -108,4 +108,15 @@
If you don't know what to do here, say N.
+config GENERIC_IRQ_DEBUGFS
+ bool "Expose irq internals in debugfs"
+ depends on DEBUG_FS
+ default n
+ ---help---
+
+ Exposes internal state information through debugfs. Mostly for
+ developers and debugging of hard to diagnose interrupt problems.
+
+ If you don't know what to do here, say N.
+
endmenu
diff --git a/kernel/irq/Makefile b/kernel/irq/Makefile
index 1d3ee31..c61fc9c 100644
--- a/kernel/irq/Makefile
+++ b/kernel/irq/Makefile
@@ -10,3 +10,4 @@
obj-$(CONFIG_GENERIC_MSI_IRQ) += msi.o
obj-$(CONFIG_GENERIC_IRQ_IPI) += ipi.o
obj-$(CONFIG_SMP) += affinity.o
+obj-$(CONFIG_GENERIC_IRQ_DEBUGFS) += debugfs.o
diff --git a/kernel/irq/debugfs.c b/kernel/irq/debugfs.c
new file mode 100644
index 0000000..50ee2f6
--- /dev/null
+++ b/kernel/irq/debugfs.c
@@ -0,0 +1,215 @@
+/*
+ * Copyright 2017 Thomas Gleixner <tglx@linutronix.de>
+ *
+ * This file is licensed under the GPL V2.
+ */
+#include <linux/debugfs.h>
+#include <linux/irqdomain.h>
+#include <linux/irq.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_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_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 const struct file_operations dfs_irq_ops = {
+ .open = irq_debug_open,
+ .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, 0444, irq_dir, desc,
+ &dfs_irq_ops);
+}
+
+void irq_remove_debugfs_entry(struct irq_desc *desc)
+{
+ if (desc->debugfs_file)
+ debugfs_remove(desc->debugfs_file);
+}
+
+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);
diff --git a/kernel/irq/internals.h b/kernel/irq/internals.h
index 921a241..094db5b 100644
--- a/kernel/irq/internals.h
+++ b/kernel/irq/internals.h
@@ -169,6 +169,11 @@ irq_put_desc_unlock(struct irq_desc *desc, unsigned long flags)
#define __irqd_to_state(d) ACCESS_PRIVATE((d)->common, state_use_accessors)
+static inline unsigned int irqd_get(struct irq_data *d)
+{
+ return __irqd_to_state(d);
+}
+
/*
* Manipulation functions for irq_data.state
*/
@@ -237,3 +242,20 @@ irq_init_generic_chip(struct irq_chip_generic *gc, const char *name,
int num_ct, unsigned int irq_base,
void __iomem *reg_base, irq_flow_handler_t handler) { }
#endif /* CONFIG_GENERIC_IRQ_CHIP */
+
+#ifdef CONFIG_GENERIC_IRQ_DEBUGFS
+void irq_add_debugfs_entry(unsigned int irq, struct irq_desc *desc);
+void irq_remove_debugfs_entry(struct irq_desc *desc);
+# ifdef CONFIG_IRQ_DOMAIN
+void irq_domain_debugfs_init(struct dentry *root);
+# else
+static inline void irq_domain_debugfs_init(struct dentry *root);
+# endif
+#else /* CONFIG_GENERIC_IRQ_DEBUGFS */
+static inline void irq_add_debugfs_entry(unsigned int irq, struct irq_desc *d)
+{
+}
+static inline void irq_remove_debugfs_entry(struct irq_desc *d)
+{
+}
+#endif /* CONFIG_GENERIC_IRQ_DEBUGFS */
diff --git a/kernel/irq/irqdesc.c b/kernel/irq/irqdesc.c
index 09abce2..feade53 100644
--- a/kernel/irq/irqdesc.c
+++ b/kernel/irq/irqdesc.c
@@ -394,6 +394,7 @@ static void free_desc(unsigned int irq)
{
struct irq_desc *desc = irq_to_desc(irq);
+ irq_remove_debugfs_entry(desc);
unregister_irq_proc(irq, desc);
/*
diff --git a/kernel/irq/irqdomain.c b/kernel/irq/irqdomain.c
index 8d5805c..75e1f08 100644
--- a/kernel/irq/irqdomain.c
+++ b/kernel/irq/irqdomain.c
@@ -29,9 +29,17 @@ struct irqchip_fwid {
struct fwnode_handle fwnode;
unsigned int type;
char *name;
- void *data;
+ void *data;
};
+#ifdef CONFIG_GENERIC_IRQ_DEBUGFS
+static void debugfs_add_domain_dir(struct irq_domain *d);
+static void debugfs_remove_domain_dir(struct irq_domain *d);
+#else
+static inline void debugfs_add_domain_dir(struct irq_domain *d) { }
+static inline void debugfs_remove_domain_dir(struct irq_domain *d) { }
+#endif
+
/**
* irq_domain_alloc_fwnode - Allocate a fwnode_handle suitable for
* identifying an irq domain
@@ -194,6 +202,7 @@ struct irq_domain *__irq_domain_add(struct fwnode_handle *fwnode, int size,
irq_domain_check_hierarchy(domain);
mutex_lock(&irq_domain_mutex);
+ debugfs_add_domain_dir(domain);
list_add(&domain->link, &irq_domain_list);
mutex_unlock(&irq_domain_mutex);
@@ -213,6 +222,7 @@ EXPORT_SYMBOL_GPL(__irq_domain_add);
void irq_domain_remove(struct irq_domain *domain)
{
mutex_lock(&irq_domain_mutex);
+ debugfs_remove_domain_dir(domain);
WARN_ON(!radix_tree_empty(&domain->revmap_tree));
@@ -1599,3 +1609,78 @@ static void irq_domain_check_hierarchy(struct irq_domain *domain)
{
}
#endif /* CONFIG_IRQ_DOMAIN_HIERARCHY */
+
+#ifdef CONFIG_GENERIC_IRQ_DEBUGFS
+static struct dentry *domain_dir;
+
+static void
+irq_domain_debug_show_one(struct seq_file *m, struct irq_domain *d, int ind)
+{
+ seq_printf(m, "%*sname: %s\n", ind, "", d->name);
+ seq_printf(m, "%*ssize: %u\n", ind + 1, "",
+ d->revmap_size + d->revmap_direct_max_irq);
+ seq_printf(m, "%*smapped: %u\n", ind + 1, "", d->mapcount);
+ seq_printf(m, "%*sflags: 0x%08x\n", ind +1 , "", d->flags);
+#ifdef CONFIG_IRQ_DOMAIN_HIERARCHY
+ if (!d->parent)
+ return;
+ seq_printf(m, "%*sparent: %s\n", ind + 1, "", d->parent->name);
+ irq_domain_debug_show_one(m, d->parent, ind + 4);
+#endif
+}
+
+static int irq_domain_debug_show(struct seq_file *m, void *p)
+{
+ struct irq_domain *d = m->private;
+
+ /* Default domain? Might be NULL */
+ if (!d) {
+ if (!irq_default_domain)
+ return 0;
+ d = irq_default_domain;
+ }
+ irq_domain_debug_show_one(m, d, 0);
+ return 0;
+}
+
+static int irq_domain_debug_open(struct inode *inode, struct file *file)
+{
+ return single_open(file, irq_domain_debug_show, inode->i_private);
+}
+
+static const struct file_operations dfs_domain_ops = {
+ .open = irq_domain_debug_open,
+ .read = seq_read,
+ .llseek = seq_lseek,
+ .release = single_release,
+};
+
+static void debugfs_add_domain_dir(struct irq_domain *d)
+{
+ if (!d->name || !domain_dir || d->debugfs_file)
+ return;
+ d->debugfs_file = debugfs_create_file(d->name, 0444, domain_dir, d,
+ &dfs_domain_ops);
+}
+
+static void debugfs_remove_domain_dir(struct irq_domain *d)
+{
+ if (d->debugfs_file)
+ debugfs_remove(d->debugfs_file);
+}
+
+void __init irq_domain_debugfs_init(struct dentry *root)
+{
+ struct irq_domain *d;
+
+ domain_dir = debugfs_create_dir("domains", root);
+ if (!domain_dir)
+ return;
+
+ debugfs_create_file("default", 0444, domain_dir, NULL, &dfs_domain_ops);
+ mutex_lock(&irq_domain_mutex);
+ list_for_each_entry(d, &irq_domain_list, link)
+ debugfs_add_domain_dir(d);
+ mutex_unlock(&irq_domain_mutex);
+}
+#endif
diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c
index 4c34696..284f4eb 100644
--- a/kernel/irq/manage.c
+++ b/kernel/irq/manage.c
@@ -1398,6 +1398,7 @@ __setup_irq(unsigned int irq, struct irq_desc *desc, struct irqaction *new)
wake_up_process(new->secondary->thread);
register_irq_proc(irq, desc);
+ irq_add_debugfs_entry(irq, desc);
new->dir = NULL;
register_handler_proc(irq, new);
free_cpumask_var(mask);