Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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linux
1/* SPDX-License-Identifier: GPL-2.0 */
2#ifndef __TOOLS_LINUX_ERR_H
3#define __TOOLS_LINUX_ERR_H
4
5#include <linux/compiler.h>
6#include <linux/types.h>
7
8#include <asm/errno.h>
9
10/*
11 * Original kernel header comment:
12 *
13 * Kernel pointers have redundant information, so we can use a
14 * scheme where we can return either an error code or a normal
15 * pointer with the same return value.
16 *
17 * This should be a per-architecture thing, to allow different
18 * error and pointer decisions.
19 *
20 * Userspace note:
21 * The same principle works for userspace, because 'error' pointers
22 * fall down to the unused hole far from user space, as described
23 * in Documentation/x86/x86_64/mm.txt for x86_64 arch:
24 *
25 * 0000000000000000 - 00007fffffffffff (=47 bits) user space, different per mm hole caused by [48:63] sign extension
26 * ffffffffffe00000 - ffffffffffffffff (=2 MB) unused hole
27 *
28 * It should be the same case for other architectures, because
29 * this code is used in generic kernel code.
30 */
31#define MAX_ERRNO 4095
32
33#define IS_ERR_VALUE(x) unlikely((x) >= (unsigned long)-MAX_ERRNO)
34
35static inline void * __must_check ERR_PTR(long error_)
36{
37 return (void *) error_;
38}
39
40static inline long __must_check PTR_ERR(__force const void *ptr)
41{
42 return (long) ptr;
43}
44
45static inline bool __must_check IS_ERR(__force const void *ptr)
46{
47 return IS_ERR_VALUE((unsigned long)ptr);
48}
49
50static inline bool __must_check IS_ERR_OR_NULL(__force const void *ptr)
51{
52 return unlikely(!ptr) || IS_ERR_VALUE((unsigned long)ptr);
53}
54
55#endif /* _LINUX_ERR_H */