LXR linux/include/linux/cache.h

   1/* SPDX-License-Identifier: GPL-2.0 */
   2#ifndef __LINUX_CACHE_H
   3#define __LINUX_CACHE_H
   4
   5#include <uapi/linux/kernel.h>
   6#include <asm/cache.h>
   7
   8#ifndef L1_CACHE_ALIGN
   9#define L1_CACHE_ALIGN(x) __ALIGN_KERNEL(x, L1_CACHE_BYTES)
  10#endif
  11
  12#ifndef SMP_CACHE_BYTES
  13#define SMP_CACHE_BYTES L1_CACHE_BYTES
  14#endif
  15
  16/*
  17 * __read_mostly is used to keep rarely changing variables out of frequently
  18 * updated cachelines. If an architecture doesn't support it, ignore the
  19 * hint.
  20 */
  21#ifndef __read_mostly
  22#define __read_mostly
  23#endif
  24
  25/*
  26 * __ro_after_init is used to mark things that are read-only after init (i.e.
  27 * after mark_rodata_ro() has been called). These are effectively read-only,
  28 * but may get written to during init, so can't live in .rodata (via "const").
  29 */
  30#ifndef __ro_after_init
  31#define __ro_after_init __attribute__((__section__(".data..ro_after_init")))
  32#endif
  33
  34#ifndef ____cacheline_aligned
  35#define ____cacheline_aligned __attribute__((__aligned__(SMP_CACHE_BYTES)))
  36#endif
  37
  38#ifndef ____cacheline_aligned_in_smp
  39#ifdef CONFIG_SMP
  40#define ____cacheline_aligned_in_smp ____cacheline_aligned
  41#else
  42#define ____cacheline_aligned_in_smp
  43#endif /* CONFIG_SMP */
  44#endif
  45
  46#ifndef __cacheline_aligned
  47#define __cacheline_aligned                                     \
  48  __attribute__((__aligned__(SMP_CACHE_BYTES),                  \
  49                 __section__(".data..cacheline_aligned")))
  50#endif /* __cacheline_aligned */
  51
  52#ifndef __cacheline_aligned_in_smp
  53#ifdef CONFIG_SMP
  54#define __cacheline_aligned_in_smp __cacheline_aligned
  55#else
  56#define __cacheline_aligned_in_smp
  57#endif /* CONFIG_SMP */
  58#endif
  59
  60/*
  61 * The maximum alignment needed for some critical structures
  62 * These could be inter-node cacheline sizes/L3 cacheline
  63 * size etc.  Define this in asm/cache.h for your arch
  64 */
  65#ifndef INTERNODE_CACHE_SHIFT
  66#define INTERNODE_CACHE_SHIFT L1_CACHE_SHIFT
  67#endif
  68
  69#if !defined(____cacheline_internodealigned_in_smp)
  70#if defined(CONFIG_SMP)
  71#define ____cacheline_internodealigned_in_smp \
  72        __attribute__((__aligned__(1 << (INTERNODE_CACHE_SHIFT))))
  73#else
  74#define ____cacheline_internodealigned_in_smp
  75#endif
  76#endif
  77
  78#ifndef CONFIG_ARCH_HAS_CACHE_LINE_SIZE
  79#define cache_line_size()       L1_CACHE_BYTES
  80#endif
  81
  82#endif /* __LINUX_CACHE_H */
  83