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