include/linux/cache.h

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