tools/virtio/linux/uaccess.h

File Facts

System

Linux kernel

Corpus path

tools/virtio/linux/uaccess.h

Extension

.h

Size

933 bytes

Lines

46

Domain

Support Tooling And Documentation

Bucket

tools

Inferred role

Support Tooling And Documentation: implementation source

Status

source implementation candidate

Why This File Exists

Repository support layer: documentation, build tooling, samples, user-space helper tools, generated initramfs support, licenses, and validation utilities.

• Repository support layer: documentation, build tooling, samples, user-space helper tools, generated initramfs support, licenses, and validation utilities.
• Touches user memory; correctness depends on fault-safe copying and privilege boundary handling.

Dependency Surface

• linux/compiler.h

Detected Declarations

• function volatile_memcpy
• function copy_from_user
• function copy_to_user

Annotated Snippet

#ifndef UACCESS_H
#define UACCESS_H

#include <linux/compiler.h>

extern void *__user_addr_min, *__user_addr_max;

#define put_user(x, ptr)					\
({								\
	typeof(ptr) __pu_ptr = (ptr);				\
	__chk_user_ptr(__pu_ptr);				\
	WRITE_ONCE(*(__pu_ptr), x);				\
	0;							\
})

#define get_user(x, ptr)					\
({								\
	typeof(ptr) __pu_ptr = (ptr);				\
	__chk_user_ptr(__pu_ptr);				\
	x = READ_ONCE(*(__pu_ptr));				\
	0;							\
})

static void volatile_memcpy(volatile char *to, const volatile char *from, 
			    unsigned long n)
{
	while (n--)
		*(to++) = *(from++);
}

static inline int copy_from_user(void *to, const void __user volatile *from,
				 unsigned long n)
{
	volatile_memcpy(to, from, n);
	return 0;
}

static inline int copy_to_user(void __user volatile *to, const void *from,
			       unsigned long n)
{
	volatile_memcpy(to, from, n);
	return 0;
}
#endif /* UACCESS_H */

Annotation

• Immediate include surface: `linux/compiler.h`.
• Detected declarations: `function volatile_memcpy`, `function copy_from_user`, `function copy_to_user`.
• Atlas domain: Support Tooling And Documentation / tools.
• Implementation status: source implementation candidate.
• This snippet crosses the user/kernel memory boundary; validate fault handling and access checks before translating the pattern.

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.