1 /* SPDX-License-Identifier: GPL-2.0 */ <<
2 #ifndef __TOOLS_LINUX_ERR_H 1 #ifndef __TOOLS_LINUX_ERR_H
3 #define __TOOLS_LINUX_ERR_H 2 #define __TOOLS_LINUX_ERR_H
4 3
5 #include <linux/compiler.h> 4 #include <linux/compiler.h>
6 #include <linux/types.h> 5 #include <linux/types.h>
7 6
8 #include <asm/errno.h> 7 #include <asm/errno.h>
9 8
10 /* 9 /*
11 * Original kernel header comment: 10 * Original kernel header comment:
12 * 11 *
13 * Kernel pointers have redundant information, 12 * Kernel pointers have redundant information, so we can use a
14 * scheme where we can return either an error 13 * scheme where we can return either an error code or a normal
15 * pointer with the same return value. 14 * pointer with the same return value.
16 * 15 *
17 * This should be a per-architecture thing, to 16 * This should be a per-architecture thing, to allow different
18 * error and pointer decisions. 17 * error and pointer decisions.
19 * 18 *
20 * Userspace note: 19 * Userspace note:
21 * The same principle works for userspace, bec 20 * The same principle works for userspace, because 'error' pointers
22 * fall down to the unused hole far from user 21 * fall down to the unused hole far from user space, as described
23 * in Documentation/arch/x86/x86_64/mm.rst for !! 22 * in Documentation/x86/x86_64/mm.txt for x86_64 arch:
24 * 23 *
25 * 0000000000000000 - 00007fffffffffff (=47 bi 24 * 0000000000000000 - 00007fffffffffff (=47 bits) user space, different per mm hole caused by [48:63] sign extension
26 * ffffffffffe00000 - ffffffffffffffff (=2 MB) 25 * ffffffffffe00000 - ffffffffffffffff (=2 MB) unused hole
27 * 26 *
28 * It should be the same case for other archit 27 * It should be the same case for other architectures, because
29 * this code is used in generic kernel code. 28 * this code is used in generic kernel code.
30 */ 29 */
31 #define MAX_ERRNO 4095 30 #define MAX_ERRNO 4095
32 31
33 #define IS_ERR_VALUE(x) unlikely((x) >= (unsig 32 #define IS_ERR_VALUE(x) unlikely((x) >= (unsigned long)-MAX_ERRNO)
34 33
35 static inline void * __must_check ERR_PTR(long 34 static inline void * __must_check ERR_PTR(long error_)
36 { 35 {
37 return (void *) error_; 36 return (void *) error_;
38 } 37 }
39 38
40 static inline long __must_check PTR_ERR(__forc 39 static inline long __must_check PTR_ERR(__force const void *ptr)
41 { 40 {
42 return (long) ptr; 41 return (long) ptr;
43 } 42 }
44 43
45 static inline bool __must_check IS_ERR(__force 44 static inline bool __must_check IS_ERR(__force const void *ptr)
46 { 45 {
47 return IS_ERR_VALUE((unsigned long)ptr 46 return IS_ERR_VALUE((unsigned long)ptr);
48 } 47 }
49 48
50 static inline bool __must_check IS_ERR_OR_NULL <<
51 { <<
52 return unlikely(!ptr) || IS_ERR_VALUE( <<
53 } <<
54 <<
55 static inline int __must_check PTR_ERR_OR_ZERO <<
56 { <<
57 if (IS_ERR(ptr)) <<
58 return PTR_ERR(ptr); <<
59 else <<
60 return 0; <<
61 } <<
62 <<
63 /** <<
64 * ERR_CAST - Explicitly cast an error-valued <<
65 * @ptr: The pointer to cast. <<
66 * <<
67 * Explicitly cast an error-valued pointer to <<
68 * way as to make it clear that's what's going <<
69 */ <<
70 static inline void * __must_check ERR_CAST(__f <<
71 { <<
72 /* cast away the const */ <<
73 return (void *) ptr; <<
74 } <<
75 #endif /* _LINUX_ERR_H */ 49 #endif /* _LINUX_ERR_H */
76 50
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