From: Craig Gallek <kr...@google.com>
Add struct kobject to struct irq_desc to allow for easy export
to sysfs. This allows for much simpler userspace-parsing of
the information contained in struct irq_desc.
Note that sysfs is not available at the time of early irq initialization.
These interrupts are accounted for using a postcore_initcall callback.
This feature is only available when both CONFIG_SPARSE_IRQ and
CONFIG_SYSFS are enabled.
Examples:
/sys/kernel/irq/18/actions: i801_smbus,ehci_hcd:usb1,uhci_hcd:usb7
/sys/kernel/irq/18/chip_name: IR-IO-APIC
/sys/kernel/irq/18/hwirq: 18
/sys/kernel/irq/18/name: fasteoi
/sys/kernel/irq/18/per_cpu_count: 0,0
/sys/kernel/irq/18/type: level
/sys/kernel/irq/25/actions: ahci0
/sys/kernel/irq/25/chip_name: IR-PCI-MSI
/sys/kernel/irq/25/hwirq: 512000
/sys/kernel/irq/25/name: edge
/sys/kernel/irq/25/per_cpu_count: 29036,0
/sys/kernel/irq/25/type: edge
Signed-off-by: Craig Gallek <kr...@google.com>
---
v5 changes:
* Change per_cpu_count: for_each_online_cpu -> for_each_possible_cpu.
v4 changes:
* Remove modifications to the !CONFIG_SPARSE_IRQ.
* Include note in documentation wrt per-cpu interrupt counters and
offline CPUs.
v3 changes:
* Add some examples to the commit message and an ABI documentation file.
* Fix spelling mistake.
v2 changes:
* Several suggested stylistic changes.
* Fix one NULL pointer dereference possibility.
* Do not destroy kobjects in non-SPARSE_IRQ configuration.
* Include #define CONFIG_SYSFS guards to selectively enable feature.
Documentation/ABI/testing/sysfs-kernel-irq | 53 +++++++++
include/linux/irqdesc.h | 3 +
kernel/irq/irqdesc.c | 185 ++++++++++++++++++++++++++++-
3 files changed, 239 insertions(+), 2 deletions(-)
create mode 100644 Documentation/ABI/testing/sysfs-kernel-irq
diff --git a/Documentation/ABI/testing/sysfs-kernel-irq
b/Documentation/ABI/testing/sysfs-kernel-irq
new file mode 100644
index 000000000000..f96a8f271b6e
--- /dev/null
+++ b/Documentation/ABI/testing/sysfs-kernel-irq
@@ -0,0 +1,53 @@
+What: /sys/kernel/irq
+Date: September 2016
+KernelVersion: 4.9
+Contact: Craig Gallek <kr...@google.com>
+Description: Directory containing information about the system's IRQs.
+ Specifically, data from the associated struct irq_desc.
+ The information here is similar to that in /proc/interrupts
+ but in a more machine-friendly format. This directory contains
+ one subdirectory for each Linux IRQ number.
+
+What: /sys/kernel/irq/<irq>/actions
+Date: September 2016
+KernelVersion: 4.9
+Contact: Craig Gallek <kr...@google.com>
+Description: The IRQ action chain. A comma-separated list of zero or more
+ device names associated with this interrupt.
+
+What: /sys/kernel/irq/<irq>/chip_name
+Date: September 2016
+KernelVersion: 4.9
+Contact: Craig Gallek <kr...@google.com>
+Description: Human-readable chip name supplied by the associated device
+ driver.
+
+What: /sys/kernel/irq/<irq>/hwirq
+Date: September 2016
+KernelVersion: 4.9
+Contact: Craig Gallek <kr...@google.com>
+Description: When interrupt translation domains are used, this file contains
+ the underlying hardware IRQ number used for this Linux IRQ.
+
+What: /sys/kernel/irq/<irq>/name
+Date: September 2016
+KernelVersion: 4.9
+Contact: Craig Gallek <kr...@google.com>
+Description: Human-readable flow handler name as defined by the device
+ driver.
+
+What: /sys/kernel/irq/<irq>/per_cpu_count
+Date: September 2016
+KernelVersion: 4.9
+Contact: Craig Gallek <kr...@google.com>
+Description: The number of times the interrupt has fired since boot. This
+ is a comma-separated list of counters; one per CPU in CPU id
+ order. NOTE: This file consistently shows counters for all
+ CPU ids. This differs from the behavior of /proc/interrupts
+ which only shows counters for online CPUs.
+
+What: /sys/kernel/irq/<irq>/type
+Date: September 2016
+KernelVersion: 4.9
+Contact: Craig Gallek <kr...@google.com>
+Description: The type of the interrupt. Either the string 'level' or 'edge'.
diff --git a/include/linux/irqdesc.h b/include/linux/irqdesc.h
index b51beebf9804..aa41d39803b2 100644
--- a/include/linux/irqdesc.h
+++ b/include/linux/irqdesc.h
@@ -2,6 +2,7 @@
#define _LINUX_IRQDESC_H
#include <linux/rcupdate.h>
+#include <linux/kobject.h>
/*
* Core internal functions to deal with irq descriptors
@@ -45,6 +46,7 @@ struct pt_regs;
* @rcu: rcu head for delayed free
* @dir: /proc/irq/ procfs entry
* @name: flow handler name for /proc/interrupts output
+ * @kobj: kobject used to represent this struct in sysfs
*/
struct irq_desc {
struct irq_common_data irq_common_data;
@@ -92,6 +94,7 @@ struct irq_desc {
int parent_irq;
struct module *owner;
const char *name;
+ struct kobject kobj;
} ____cacheline_internodealigned_in_smp;
#ifdef CONFIG_SPARSE_IRQ
diff --git a/kernel/irq/irqdesc.c b/kernel/irq/irqdesc.c
index a623b44f2d4b..2bc903505f6b 100644
--- a/kernel/irq/irqdesc.c
+++ b/kernel/irq/irqdesc.c
@@ -15,6 +15,7 @@
#include <linux/radix-tree.h>
#include <linux/bitmap.h>
#include <linux/irqdomain.h>
+#include <linux/sysfs.h>
#include "internals.h"
@@ -123,6 +124,154 @@ static DECLARE_BITMAP(allocated_irqs, IRQ_BITMAP_BITS);
#ifdef CONFIG_SPARSE_IRQ
+static void irq_kobj_release(struct kobject *kobj);
+
+#ifdef CONFIG_SYSFS
+static struct kobject *irq_kobj_base;
+
+#define IRQ_ATTR_RO(_name) \
+static struct kobj_attribute _name##_attr = __ATTR_RO(_name)
+
+static ssize_t per_cpu_count_show(struct kobject *kobj,
+ struct kobj_attribute *attr, char *buf)
+{
+ struct irq_desc *desc = container_of(kobj, struct irq_desc, kobj);
+ int cpu, irq = desc->irq_data.irq;
+ ssize_t ret = 0;
+ char *p = "";
+
+ for_each_possible_cpu(cpu) {
+ unsigned int c = kstat_irqs_cpu(irq, cpu);
+
+ ret += scnprintf(buf + ret, PAGE_SIZE - ret, "%s%u", p, c);
+ p = ",";
+ }
+
+ ret += scnprintf(buf + ret, PAGE_SIZE - ret, "\n");
+ return ret;
+}
+IRQ_ATTR_RO(per_cpu_count);
+
+static ssize_t chip_name_show(struct kobject *kobj,
+ struct kobj_attribute *attr, char *buf)
+{
+ struct irq_desc *desc = container_of(kobj, struct irq_desc, kobj);
+ ssize_t ret = 0;
+
+ raw_spin_lock_irq(&desc->lock);
+ if (desc->irq_data.chip && desc->irq_data.chip->name) {
+ ret = scnprintf(buf, PAGE_SIZE, "%s\n",
+ desc->irq_data.chip->name);
+ }
+ raw_spin_unlock_irq(&desc->lock);
+
+ return ret;
+}
+IRQ_ATTR_RO(chip_name);
+
+static ssize_t hwirq_show(struct kobject *kobj,
+ struct kobj_attribute *attr, char *buf)
+{
+ struct irq_desc *desc = container_of(kobj, struct irq_desc, kobj);
+ ssize_t ret = 0;
+
+ raw_spin_lock_irq(&desc->lock);
+ if (desc->irq_data.domain)
+ ret = sprintf(buf, "%d\n", (int)desc->irq_data.hwirq);
+ raw_spin_unlock_irq(&desc->lock);
+
+ return ret;
+}
+IRQ_ATTR_RO(hwirq);
+
+static ssize_t type_show(struct kobject *kobj,
+ struct kobj_attribute *attr, char *buf)
+{
+ struct irq_desc *desc = container_of(kobj, struct irq_desc, kobj);
+ ssize_t ret = 0;
+
+ raw_spin_lock_irq(&desc->lock);
+ ret = sprintf(buf, "%s\n",
+ irqd_is_level_type(&desc->irq_data) ? "level" : "edge");
+ raw_spin_unlock_irq(&desc->lock);
+
+ return ret;
+
+}
+IRQ_ATTR_RO(type);
+
+static ssize_t name_show(struct kobject *kobj,
+ struct kobj_attribute *attr, char *buf)
+{
+ struct irq_desc *desc = container_of(kobj, struct irq_desc, kobj);
+ ssize_t ret = 0;
+
+ raw_spin_lock_irq(&desc->lock);
+ if (desc->name)
+ ret = scnprintf(buf, PAGE_SIZE, "%s\n", desc->name);
+ raw_spin_unlock_irq(&desc->lock);
+
+ return ret;
+}
+IRQ_ATTR_RO(name);
+
+static ssize_t actions_show(struct kobject *kobj,
+ struct kobj_attribute *attr, char *buf)
+{
+ struct irq_desc *desc = container_of(kobj, struct irq_desc, kobj);
+ struct irqaction *action;
+ ssize_t ret = 0;
+ char *p = "";
+
+ raw_spin_lock_irq(&desc->lock);
+ for (action = desc->action; action != NULL; action = action->next) {
+ ret += scnprintf(buf + ret, PAGE_SIZE - ret, "%s%s",
+ p, action->name);
+ p = ",";
+ }
+ raw_spin_unlock_irq(&desc->lock);
+
+ if (ret)
+ ret += scnprintf(buf + ret, PAGE_SIZE - ret, "\n");
+
+ return ret;
+}
+IRQ_ATTR_RO(actions);
+
+static struct attribute *irq_attrs[] = {
+ &per_cpu_count_attr.attr,
+ &chip_name_attr.attr,
+ &hwirq_attr.attr,
+ &type_attr.attr,
+ &name_attr.attr,
+ &actions_attr.attr,
+ NULL
+};
+
+static struct kobj_type irq_kobj_type = {
+ .release = irq_kobj_release,
+ .sysfs_ops = &kobj_sysfs_ops,
+ .default_attrs = irq_attrs,
+};
+
+static void irq_sysfs_add(int irq, struct irq_desc *desc)
+{
+ if (irq_kobj_base) {
+ if (kobject_add(&desc->kobj, irq_kobj_base, "%d", irq))
+ pr_warn("Failed to add kobject for irq %d\n", irq);
+ }
+}
+
+#else /* !CONFIG_SYSFS */
+
+static struct kobj_type irq_kobj_type = {
+ .release = irq_kobj_release,
+};
+
+static void irq_sysfs_add(int irq, struct irq_desc *desc) {}
+
+#endif /* CONFIG_SYSFS */
+
static RADIX_TREE(irq_desc_tree, GFP_KERNEL);
static void irq_insert_desc(unsigned int irq, struct irq_desc *desc)
@@ -187,6 +336,7 @@ static struct irq_desc *alloc_desc(int irq, int node,
unsigned int flags,
desc_set_defaults(irq, desc, node, affinity, owner);
irqd_set(&desc->irq_data, flags);
+ kobject_init(&desc->kobj, &irq_kobj_type);
return desc;
@@ -197,20 +347,28 @@ err_desc:
return NULL;
}
-static void delayed_free_desc(struct rcu_head *rhp)
+static void irq_kobj_release(struct kobject *kobj)
{
- struct irq_desc *desc = container_of(rhp, struct irq_desc, rcu);
+ struct irq_desc *desc = container_of(kobj, struct irq_desc, kobj);
free_masks(desc);
free_percpu(desc->kstat_irqs);
kfree(desc);
}
+static void delayed_free_desc(struct rcu_head *rhp)
+{
+ struct irq_desc *desc = container_of(rhp, struct irq_desc, rcu);
+
+ kobject_put(&desc->kobj);
+}
+
static void free_desc(unsigned int irq)
{
struct irq_desc *desc = irq_to_desc(irq);
unregister_irq_proc(irq, desc);
+ kobject_del(&desc->kobj);
/*
* sparse_irq_lock protects also show_interrupts() and
@@ -261,6 +419,7 @@ static int alloc_descs(unsigned int start, unsigned int
cnt, int node,
goto err;
mutex_lock(&sparse_irq_lock);
irq_insert_desc(start + i, desc);
+ irq_sysfs_add(start + i, desc);
mutex_unlock(&sparse_irq_lock);
}
return start;
@@ -730,3 +889,25 @@ unsigned int kstat_irqs_usr(unsigned int irq)
irq_unlock_sparse();
return sum;
}
+
+#ifdef CONFIG_SPARSE_IRQ
+#ifdef CONFIG_SYSFS
+static int __init irq_sysfs_init(void)
+{
+ struct irq_desc *desc;
+ int irq;
+
+ irq_kobj_base = kobject_create_and_add("irq", kernel_kobj);
+ if (!irq_kobj_base)
+ return -ENOMEM;
+
+ irq_lock_sparse();
+ for_each_irq_desc(irq, desc)
+ irq_sysfs_add(irq, desc);
+ irq_unlock_sparse();
+
+ return 0;
+}
+postcore_initcall(irq_sysfs_init);
+#endif /* CONFIG_SYSFS */
+#endif /* CONFIG_SPARSE_IRQ */
--
2.8.0.rc3.226.g39d4020
