arch/um/include/asm/uaccess.h

Source file repositories/reference/linux-study-clean/arch/um/include/asm/uaccess.h

File Facts

System
Linux kernel
Corpus path
arch/um/include/asm/uaccess.h
Extension
.h
Size
1958 bytes
Lines
67
Domain
Architecture Layer
Bucket
arch/um
Inferred role
Architecture Layer: implementation source
Status
source implementation candidate

Why This File Exists

CPU and platform-specific kernel glue: boot entry, traps, syscall entry, interrupts, page tables, context switch, and low-level barriers.

Dependency Surface

Detected Declarations

Annotated Snippet

#ifndef __UM_UACCESS_H
#define __UM_UACCESS_H

#include <asm/elf.h>
#include <linux/unaligned.h>
#include <sysdep/faultinfo.h>

#define __under_task_size(addr, size) \
	(((unsigned long) (addr) < TASK_SIZE) && \
	 (((unsigned long) (addr) + (size)) < TASK_SIZE))

#define __addr_range_nowrap(addr, size) \
	((unsigned long) (addr) <= ((unsigned long) (addr) + (size)))

extern unsigned long raw_copy_from_user(void *to, const void __user *from, unsigned long n);
extern unsigned long raw_copy_to_user(void __user *to, const void *from, unsigned long n);
extern unsigned long __clear_user(void __user *mem, unsigned long len);
static inline int __access_ok(const void __user *ptr, unsigned long size);

/* Teach asm-generic/uaccess.h that we have C functions for these. */
#define __access_ok __access_ok
#define __clear_user __clear_user

#define INLINE_COPY_USER

#include <asm-generic/uaccess.h>

static inline int __access_ok(const void __user *ptr, unsigned long size)
{
	unsigned long addr = (unsigned long)ptr;
	return __addr_range_nowrap(addr, size) && __under_task_size(addr, size);
}

#define __get_kernel_nofault(dst, src, type, err_label)			\
do {									\
	int __faulted;							\
									\
	___backtrack_faulted(__faulted);				\
	if (__faulted) {						\
		*((type *)dst) = (type) 0;				\
		goto err_label;						\
	}								\
	*((type *)dst) = get_unaligned((type *)(src));			\
	barrier();							\
	current->thread.segv_continue = NULL;				\
} while (0)

#define __put_kernel_nofault(dst, src, type, err_label)			\
do {									\
	int __faulted;							\
									\
	___backtrack_faulted(__faulted);				\
	if (__faulted)							\
		goto err_label;						\
	put_unaligned(*((type *)src), (type *)(dst));			\
	barrier();							\
	current->thread.segv_continue = NULL;				\
} while (0)

#endif

Annotation

Implementation Notes