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- /* 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 */
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