Kernel/linux-stable
1
0
Fork 0
mirror of https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git synced 2025-01-07 13:43:51 +00:00
Code Issues Actions Packages Projects Releases Wiki Activity

libeth: add cacheline / struct layout assertion helpers

Browse Source 
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>
This commit is contained in:
Alexander Lobakin 2024-06-20 15:53:36 +02:00 committed by Tony Nguyen
parent 39daa09d34
commit 62c884256e
1 changed files with 66 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

66
include/net/libeth/cache.h Normal file
View File

@ -0,0 +1,66 @@
/* SPDX-License-Identifier: GPL-2.0-only */
/* Copyright (C) 2024 Intel Corporation */
#ifndef __LIBETH_CACHE_H
#define __LIBETH_CACHE_H
#include <linux/cache.h>
/**
* libeth_cacheline_group_assert - make sure cacheline group size is expected
* @type: type of the structure containing the group
* @grp: group name inside the struct
* @sz: expected group size
*/
#if defined(CONFIG_64BIT) && SMP_CACHE_BYTES == 64
#define libeth_cacheline_group_assert(type, grp, sz) \
static_assert(offsetof(type, __cacheline_group_end__##grp) - \
offsetofend(type, __cacheline_group_begin__##grp) == \
(sz))
#define __libeth_cacheline_struct_assert(type, sz) \
static_assert(sizeof(type) == (sz))
#else /* !CONFIG_64BIT || SMP_CACHE_BYTES != 64 */
#define libeth_cacheline_group_assert(type, grp, sz) \
static_assert(offsetof(type, __cacheline_group_end__##grp) - \
offsetofend(type, __cacheline_group_begin__##grp) <= \
(sz))
#define __libeth_cacheline_struct_assert(type, sz) \
static_assert(sizeof(type) <= (sz))
#endif /* !CONFIG_64BIT || SMP_CACHE_BYTES != 64 */
#define __libeth_cls1(sz1) SMP_CACHE_ALIGN(sz1)
#define __libeth_cls2(sz1, sz2) (SMP_CACHE_ALIGN(sz1) + SMP_CACHE_ALIGN(sz2))
#define __libeth_cls3(sz1, sz2, sz3) \
(SMP_CACHE_ALIGN(sz1) + SMP_CACHE_ALIGN(sz2) + SMP_CACHE_ALIGN(sz3))
#define __libeth_cls(...) \
CONCATENATE(__libeth_cls, COUNT_ARGS(__VA_ARGS__))(__VA_ARGS__)
/**
* libeth_cacheline_struct_assert - make sure CL-based struct size is expected
* @type: type of the struct
* @...: from 1 to 3 CL group sizes (read-mostly, read-write, cold)
*
* When a struct contains several CL groups, it's difficult to predict its size
* on different architectures. The macro instead takes sizes of all of the
* groups the structure contains and generates the final struct size.
*/
#define libeth_cacheline_struct_assert(type, ...) \
__libeth_cacheline_struct_assert(type, __libeth_cls(__VA_ARGS__)); \
static_assert(__alignof(type) >= SMP_CACHE_BYTES)
/**
* libeth_cacheline_set_assert - make sure CL-based struct layout is expected
* @type: type of the struct
* @ro: expected size of the read-mostly group
* @rw: expected size of the read-write group
* @c: expected size of the cold group
*
* Check that each group size is expected and then do final struct size check.
*/
#define libeth_cacheline_set_assert(type, ro, rw, c) \
libeth_cacheline_group_assert(type, read_mostly, ro); \
libeth_cacheline_group_assert(type, read_write, rw); \
libeth_cacheline_group_assert(type, cold, c); \
libeth_cacheline_struct_assert(type, ro, rw, c)
#endif /* __LIBETH_CACHE_H */