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.rst 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 ERR_PTR(long error_)35static inline void * __must_check ERR_PTR(long error_) 36 { 37 return (void *) error_; 38 } 39 PTR_ERR(__force const void * ptr)40static inline long __must_check PTR_ERR(__force const void *ptr) 41 { 42 return (long) ptr; 43 } 44 IS_ERR(__force const void * ptr)45static inline bool __must_check IS_ERR(__force const void *ptr) 46 { 47 return IS_ERR_VALUE((unsigned long)ptr); 48 } 49 IS_ERR_OR_NULL(__force const void * ptr)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 PTR_ERR_OR_ZERO(__force const void * ptr)55static inline int __must_check PTR_ERR_OR_ZERO(__force const void *ptr) 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 pointer to another pointer type 65 * @ptr: The pointer to cast. 66 * 67 * Explicitly cast an error-valued pointer to another pointer type in such a 68 * way as to make it clear that's what's going on. 69 */ ERR_CAST(__force const void * ptr)70static inline void * __must_check ERR_CAST(__force const void *ptr) 71 { 72 /* cast away the const */ 73 return (void *) ptr; 74 } 75 #endif /* _LINUX_ERR_H */ 76