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1/* SPDX-License-Identifier: GPL-2.0 */2#ifndef __TOOLS_LINUX_ERR_H3#define __TOOLS_LINUX_ERR_H4 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 a14 * scheme where we can return either an error code or a normal15 * pointer with the same return value.16 *17 * This should be a per-architecture thing, to allow different18 * error and pointer decisions.19 *20 * Userspace note:21 * The same principle works for userspace, because 'error' pointers22 * fall down to the unused hole far from user space, as described23 * in Documentation/arch/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 extension26 * ffffffffffe00000 - ffffffffffffffff (=2 MB) unused hole27 *28 * It should be the same case for other architectures, because29 * this code is used in generic kernel code.30 */31#define MAX_ERRNO 409532 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 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 else60 return 0;61}62 63/**64 * ERR_CAST - Explicitly cast an error-valued pointer to another pointer type65 * @ptr: The pointer to cast.66 *67 * Explicitly cast an error-valued pointer to another pointer type in such a68 * way as to make it clear that's what's going on.69 */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