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