1 #ifndef __TOOLS_LINUX_ERR_H
2 #define __TOOLS_LINUX_ERR_H
4 #include <linux/compiler.h>
5 #include <linux/types.h>
10 * Original kernel header comment:
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.
16 * This should be a per-architecture thing, to allow different
17 * error and pointer decisions.
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:
24 * 0000000000000000 - 00007fffffffffff (=47 bits) user space, different per mm hole caused by [48:63] sign extension
25 * ffffffffffe00000 - ffffffffffffffff (=2 MB) unused hole
27 * It should be the same case for other architectures, because
28 * this code is used in generic kernel code.
30 #define MAX_ERRNO 4095
32 #define IS_ERR_VALUE(x) unlikely((x) >= (unsigned long)-MAX_ERRNO)
34 static inline void * __must_check ERR_PTR(long error_)
36 return (void *) error_;
39 static inline long __must_check PTR_ERR(__force const void *ptr)
44 static inline bool __must_check IS_ERR(__force const void *ptr)
46 return IS_ERR_VALUE((unsigned long)ptr);
49 #endif /* _LINUX_ERR_H */