kernel/irq/debugfs.c

File Facts

System

Linux kernel

Corpus path

kernel/irq/debugfs.c

Extension

.c

Size

7186 bytes

Lines

257

Domain

Core OS

Bucket

Scheduler, Processes, Timers, Sync, And Syscalls

Inferred role

Core OS: operation-table or driver-model contract

Status

pattern implementation candidate

Why This File Exists

Core operating-system implementation surface: boot, tasks, memory, VFS, syscall-facing interfaces, synchronization, credentials, and isolation.

• Core operating-system implementation surface: boot, tasks, memory, VFS, syscall-facing interfaces, synchronization, credentials, and isolation.
• Defines an operation table; this is where Linux turns generic core objects into subsystem-specific behavior.
• Touches user memory; correctness depends on fault-safe copying and privilege boundary handling.
• Touches IRQ or DMA behavior; this matters for the representative real-device path.
• Defines or uses C structs; map object ownership, embedded links, reference counts, and lock ownership.

Dependency Surface

• linux/irqdomain.h
• linux/irq.h
• linux/uaccess.h
• internals.h

Detected Declarations

• function irq_debug_show_bits
• function irq_debug_show_masks
• function irq_debug_show_masks
• function irq_debug_show_chip
• function irq_debug_show_data
• function irq_debug_show
• function irq_debug_open
• function irq_debug_write
• function irq_debugfs_copy_devname
• function irq_add_debugfs_entry
• function irq_debugfs_init

Annotated Snippet

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_debugfs_copy_devname(int irq, struct device *dev)
{
	struct irq_desc *desc = irq_to_desc(irq);
	const char *name = dev_name(dev);

	if (name)
		desc->dev_name = kstrdup(name, GFP_KERNEL);
}

void irq_add_debugfs_entry(unsigned int irq, struct irq_desc *desc)
{
	char name [12];

	if (!irq_dir || !desc || desc->debugfs_file)
		return;

	sprintf(name, "%u", 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);

	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);

Annotation

• Immediate include surface: `linux/irqdomain.h`, `linux/irq.h`, `linux/uaccess.h`, `internals.h`.
• Detected declarations: `function irq_debug_show_bits`, `function irq_debug_show_masks`, `function irq_debug_show_masks`, `function irq_debug_show_chip`, `function irq_debug_show_data`, `function irq_debug_show`, `function irq_debug_open`, `function irq_debug_write`, `function irq_debugfs_copy_devname`, `function irq_add_debugfs_entry`.
• Atlas domain: Core OS / Scheduler, Processes, Timers, Sync, And Syscalls.
• Implementation status: pattern implementation candidate.
• This snippet crosses the user/kernel memory boundary; validate fault handling and access checks before translating the pattern.
• IRQ or DMA behavior appears here, which is relevant to the selected PCIe/NVMe device path.

Implementation Notes

• This generated page is the file-by-file coverage layer; curated subsystem chapters should link here when they synthesize a multi-file control flow.
• Core OS pages should be promoted from atlas-only to deep-reviewed when they explain data structures, invariants, locking, lifecycle, and C implementation snippets.
• Driver-family pages are intentionally pattern-oriented unless they are part of the selected PCIe/NVMe representative device path.