| 1 | /* SPDX-License-Identifier: GPL-2.0 */ |
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| 2 | #ifndef _LINUX_STDDEF_H |
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| 3 | #define _LINUX_STDDEF_H |
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| 4 | |
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| 5 | #include <uapi/linux/stddef.h> |
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| 6 | |
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| 7 | #undef NULL |
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| 8 | #define NULL ((void *)0) |
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| 9 | |
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| 10 | enum { |
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| 11 | false = 0, |
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| 12 | true = 1 |
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| 13 | }; |
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| 14 | |
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| 15 | #undef offsetof |
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| 16 | #define offsetof(TYPE, MEMBER) __builtin_offsetof(TYPE, MEMBER) |
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| 17 | |
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| 18 | /** |
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| 19 | * sizeof_field() - Report the size of a struct field in bytes |
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| 20 | * |
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| 21 | * @TYPE: The structure containing the field of interest |
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| 22 | * @MEMBER: The field to return the size of |
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| 23 | */ |
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| 24 | #define sizeof_field(TYPE, MEMBER) sizeof((((TYPE *)0)->MEMBER)) |
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| 25 | |
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| 26 | /** |
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| 27 | * offsetofend() - Report the offset of a struct field within the struct |
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| 28 | * |
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| 29 | * @TYPE: The type of the structure |
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| 30 | * @MEMBER: The member within the structure to get the end offset of |
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| 31 | */ |
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| 32 | #define offsetofend(TYPE, MEMBER) \ |
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| 33 | (offsetof(TYPE, MEMBER) + sizeof_field(TYPE, MEMBER)) |
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| 34 | |
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| 35 | /** |
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| 36 | * struct_group() - Wrap a set of declarations in a mirrored struct |
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| 37 | * |
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| 38 | * @NAME: The identifier name of the mirrored sub-struct |
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| 39 | * @MEMBERS: The member declarations for the mirrored structs |
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| 40 | * |
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| 41 | * Used to create an anonymous union of two structs with identical |
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| 42 | * layout and size: one anonymous and one named. The former can be |
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| 43 | * used normally without sub-struct naming, and the latter can be |
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| 44 | * used to reason about the start, end, and size of the group of |
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| 45 | * struct members. |
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| 46 | */ |
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| 47 | #define struct_group(NAME, MEMBERS...) \ |
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| 48 | __struct_group(/* no tag */, NAME, /* no attrs */, MEMBERS) |
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| 49 | |
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| 50 | /** |
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| 51 | * struct_group_attr() - Create a struct_group() with trailing attributes |
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| 52 | * |
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| 53 | * @NAME: The identifier name of the mirrored sub-struct |
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| 54 | * @ATTRS: Any struct attributes to apply |
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| 55 | * @MEMBERS: The member declarations for the mirrored structs |
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| 56 | * |
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| 57 | * Used to create an anonymous union of two structs with identical |
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| 58 | * layout and size: one anonymous and one named. The former can be |
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| 59 | * used normally without sub-struct naming, and the latter can be |
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| 60 | * used to reason about the start, end, and size of the group of |
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| 61 | * struct members. Includes structure attributes argument. |
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| 62 | */ |
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| 63 | #define struct_group_attr(NAME, ATTRS, MEMBERS...) \ |
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| 64 | __struct_group(/* no tag */, NAME, ATTRS, MEMBERS) |
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| 65 | |
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| 66 | /** |
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| 67 | * struct_group_tagged() - Create a struct_group with a reusable tag |
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| 68 | * |
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| 69 | * @TAG: The tag name for the named sub-struct |
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| 70 | * @NAME: The identifier name of the mirrored sub-struct |
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| 71 | * @MEMBERS: The member declarations for the mirrored structs |
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| 72 | * |
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| 73 | * Used to create an anonymous union of two structs with identical |
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| 74 | * layout and size: one anonymous and one named. The former can be |
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| 75 | * used normally without sub-struct naming, and the latter can be |
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| 76 | * used to reason about the start, end, and size of the group of |
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| 77 | * struct members. Includes struct tag argument for the named copy, |
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| 78 | * so the specified layout can be reused later. |
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| 79 | */ |
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| 80 | #define struct_group_tagged(TAG, NAME, MEMBERS...) \ |
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| 81 | __struct_group(TAG, NAME, /* no attrs */, MEMBERS) |
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| 82 | |
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| 83 | /** |
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| 84 | * DECLARE_FLEX_ARRAY() - Declare a flexible array usable in a union |
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| 85 | * |
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| 86 | * @TYPE: The type of each flexible array element |
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| 87 | * @NAME: The name of the flexible array member |
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| 88 | * |
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| 89 | * In order to have a flexible array member in a union or alone in a |
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| 90 | * struct, it needs to be wrapped in an anonymous struct with at least 1 |
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| 91 | * named member, but that member can be empty. |
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| 92 | */ |
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| 93 | #define DECLARE_FLEX_ARRAY(TYPE, NAME) \ |
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| 94 | __DECLARE_FLEX_ARRAY(TYPE, NAME) |
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| 95 | |
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| 96 | #endif |
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| 97 | |
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