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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 */
82