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01ca9fd4 JO |
1 | #ifndef __TOOLS_LINUX_ERR_H |
2 | #define __TOOLS_LINUX_ERR_H | |
3 | ||
4 | #include <linux/compiler.h> | |
5 | #include <linux/types.h> | |
6 | ||
7 | #include <asm/errno.h> | |
8 | ||
9 | /* | |
10 | * Original kernel header comment: | |
11 | * | |
12 | * Kernel pointers have redundant information, so we can use a | |
13 | * scheme where we can return either an error code or a normal | |
14 | * pointer with the same return value. | |
15 | * | |
16 | * This should be a per-architecture thing, to allow different | |
17 | * error and pointer decisions. | |
18 | * | |
19 | * Userspace note: | |
20 | * The same principle works for userspace, because 'error' pointers | |
21 | * fall down to the unused hole far from user space, as described | |
22 | * in Documentation/x86/x86_64/mm.txt for x86_64 arch: | |
23 | * | |
24 | * 0000000000000000 - 00007fffffffffff (=47 bits) user space, different per mm hole caused by [48:63] sign extension | |
25 | * ffffffffffe00000 - ffffffffffffffff (=2 MB) unused hole | |
26 | * | |
27 | * It should be the same case for other architectures, because | |
28 | * this code is used in generic kernel code. | |
29 | */ | |
30 | #define MAX_ERRNO 4095 | |
31 | ||
32 | #define IS_ERR_VALUE(x) unlikely((x) >= (unsigned long)-MAX_ERRNO) | |
33 | ||
45633a16 | 34 | static inline void * __must_check ERR_PTR(long error_) |
01ca9fd4 | 35 | { |
45633a16 | 36 | return (void *) error_; |
01ca9fd4 JO |
37 | } |
38 | ||
39 | static inline long __must_check PTR_ERR(__force const void *ptr) | |
40 | { | |
41 | return (long) ptr; | |
42 | } | |
43 | ||
44 | static inline bool __must_check IS_ERR(__force const void *ptr) | |
45 | { | |
46 | return IS_ERR_VALUE((unsigned long)ptr); | |
47 | } | |
48 | ||
49 | #endif /* _LINUX_ERR_H */ |