| /* SPDX-License-Identifier: GPL-2.0 */ |
| #ifndef __TOOLS_LINUX_ERR_H |
| #define __TOOLS_LINUX_ERR_H |
| |
| #include <linux/compiler.h> |
| #include <linux/types.h> |
| |
| #include <asm/errno.h> |
| |
| /* |
| * Original kernel header comment: |
| * |
| * Kernel pointers have redundant information, so we can use a |
| * scheme where we can return either an error code or a normal |
| * pointer with the same return value. |
| * |
| * This should be a per-architecture thing, to allow different |
| * error and pointer decisions. |
| * |
| * Userspace note: |
| * The same principle works for userspace, because 'error' pointers |
| * fall down to the unused hole far from user space, as described |
| * in Documentation/x86/x86_64/mm.rst for x86_64 arch: |
| * |
| * 0000000000000000 - 00007fffffffffff (=47 bits) user space, different per mm hole caused by [48:63] sign extension |
| * ffffffffffe00000 - ffffffffffffffff (=2 MB) unused hole |
| * |
| * It should be the same case for other architectures, because |
| * this code is used in generic kernel code. |
| */ |
| #define MAX_ERRNO 4095 |
| |
| #define IS_ERR_VALUE(x) unlikely((x) >= (unsigned long)-MAX_ERRNO) |
| |
| static inline void * __must_check ERR_PTR(long error_) |
| { |
| return (void *) error_; |
| } |
| |
| static inline long __must_check PTR_ERR(__force const void *ptr) |
| { |
| return (long) ptr; |
| } |
| |
| static inline bool __must_check IS_ERR(__force const void *ptr) |
| { |
| return IS_ERR_VALUE((unsigned long)ptr); |
| } |
| |
| static inline bool __must_check IS_ERR_OR_NULL(__force const void *ptr) |
| { |
| return unlikely(!ptr) || IS_ERR_VALUE((unsigned long)ptr); |
| } |
| |
| static inline int __must_check PTR_ERR_OR_ZERO(__force const void *ptr) |
| { |
| if (IS_ERR(ptr)) |
| return PTR_ERR(ptr); |
| else |
| return 0; |
| } |
| |
| /** |
| * ERR_CAST - Explicitly cast an error-valued pointer to another pointer type |
| * @ptr: The pointer to cast. |
| * |
| * Explicitly cast an error-valued pointer to another pointer type in such a |
| * way as to make it clear that's what's going on. |
| */ |
| static inline void * __must_check ERR_CAST(__force const void *ptr) |
| { |
| /* cast away the const */ |
| return (void *) ptr; |
| } |
| #endif /* _LINUX_ERR_H */ |