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62c884256e
Add helpers to assert struct field layout, a bit more crazy and networking-specific than in <linux/cache.h>. They assume you have 3 CL-aligned groups (read-mostly, read-write, cold) in a struct you want to assert, and nothing besides them. For 64-bit with 64-byte cachelines, the assertions are as strict as possible, as the size can then be easily predicted. For the rest, make sure they don't cross the specified bound. Signed-off-by: Alexander Lobakin <aleksander.lobakin@intel.com> Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>
67 lines
2.7 KiB
C
67 lines
2.7 KiB
C
/* SPDX-License-Identifier: GPL-2.0-only */
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/* Copyright (C) 2024 Intel Corporation */
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#ifndef __LIBETH_CACHE_H
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#define __LIBETH_CACHE_H
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#include <linux/cache.h>
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/**
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* libeth_cacheline_group_assert - make sure cacheline group size is expected
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* @type: type of the structure containing the group
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* @grp: group name inside the struct
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* @sz: expected group size
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*/
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#if defined(CONFIG_64BIT) && SMP_CACHE_BYTES == 64
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#define libeth_cacheline_group_assert(type, grp, sz) \
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static_assert(offsetof(type, __cacheline_group_end__##grp) - \
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offsetofend(type, __cacheline_group_begin__##grp) == \
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(sz))
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#define __libeth_cacheline_struct_assert(type, sz) \
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static_assert(sizeof(type) == (sz))
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#else /* !CONFIG_64BIT || SMP_CACHE_BYTES != 64 */
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#define libeth_cacheline_group_assert(type, grp, sz) \
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static_assert(offsetof(type, __cacheline_group_end__##grp) - \
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offsetofend(type, __cacheline_group_begin__##grp) <= \
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(sz))
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#define __libeth_cacheline_struct_assert(type, sz) \
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static_assert(sizeof(type) <= (sz))
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#endif /* !CONFIG_64BIT || SMP_CACHE_BYTES != 64 */
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#define __libeth_cls1(sz1) SMP_CACHE_ALIGN(sz1)
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#define __libeth_cls2(sz1, sz2) (SMP_CACHE_ALIGN(sz1) + SMP_CACHE_ALIGN(sz2))
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#define __libeth_cls3(sz1, sz2, sz3) \
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(SMP_CACHE_ALIGN(sz1) + SMP_CACHE_ALIGN(sz2) + SMP_CACHE_ALIGN(sz3))
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#define __libeth_cls(...) \
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CONCATENATE(__libeth_cls, COUNT_ARGS(__VA_ARGS__))(__VA_ARGS__)
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/**
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* libeth_cacheline_struct_assert - make sure CL-based struct size is expected
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* @type: type of the struct
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* @...: from 1 to 3 CL group sizes (read-mostly, read-write, cold)
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*
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* When a struct contains several CL groups, it's difficult to predict its size
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* on different architectures. The macro instead takes sizes of all of the
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* groups the structure contains and generates the final struct size.
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*/
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#define libeth_cacheline_struct_assert(type, ...) \
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__libeth_cacheline_struct_assert(type, __libeth_cls(__VA_ARGS__)); \
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static_assert(__alignof(type) >= SMP_CACHE_BYTES)
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/**
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* libeth_cacheline_set_assert - make sure CL-based struct layout is expected
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* @type: type of the struct
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* @ro: expected size of the read-mostly group
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* @rw: expected size of the read-write group
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* @c: expected size of the cold group
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*
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* Check that each group size is expected and then do final struct size check.
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*/
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#define libeth_cacheline_set_assert(type, ro, rw, c) \
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libeth_cacheline_group_assert(type, read_mostly, ro); \
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libeth_cacheline_group_assert(type, read_write, rw); \
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libeth_cacheline_group_assert(type, cold, c); \
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libeth_cacheline_struct_assert(type, ro, rw, c)
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#endif /* __LIBETH_CACHE_H */
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