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b2441318 | 1 | /* SPDX-License-Identifier: GPL-2.0 */ |
1da177e4 LT |
2 | /* |
3 | * Generic cache management functions. Everything is arch-specific, | |
4 | * but this header exists to make sure the defines/functions can be | |
5 | * used in a generic way. | |
6 | * | |
7 | * 2000-11-13 Arjan van de Ven <arjan@fenrus.demon.nl> | |
8 | * | |
9 | */ | |
10 | ||
11 | #ifndef _LINUX_PREFETCH_H | |
12 | #define _LINUX_PREFETCH_H | |
13 | ||
14 | #include <linux/types.h> | |
15 | #include <asm/processor.h> | |
16 | #include <asm/cache.h> | |
17 | ||
18 | /* | |
19 | prefetch(x) attempts to pre-emptively get the memory pointed to | |
20 | by address "x" into the CPU L1 cache. | |
21 | prefetch(x) should not cause any kind of exception, prefetch(0) is | |
22 | specifically ok. | |
23 | ||
24 | prefetch() should be defined by the architecture, if not, the | |
25 | #define below provides a no-op define. | |
26 | ||
27 | There are 3 prefetch() macros: | |
28 | ||
29 | prefetch(x) - prefetches the cacheline at "x" for read | |
30 | prefetchw(x) - prefetches the cacheline at "x" for write | |
52161845 | 31 | spin_lock_prefetch(x) - prefetches the spinlock *x for taking |
1da177e4 | 32 | |
25985edc | 33 | there is also PREFETCH_STRIDE which is the architecure-preferred |
1da177e4 LT |
34 | "lookahead" size for prefetching streamed operations. |
35 | ||
36 | */ | |
37 | ||
1da177e4 | 38 | #ifndef ARCH_HAS_PREFETCH |
ab483570 | 39 | #define prefetch(x) __builtin_prefetch(x) |
1da177e4 LT |
40 | #endif |
41 | ||
42 | #ifndef ARCH_HAS_PREFETCHW | |
ab483570 | 43 | #define prefetchw(x) __builtin_prefetch(x,1) |
1da177e4 LT |
44 | #endif |
45 | ||
46 | #ifndef ARCH_HAS_SPINLOCK_PREFETCH | |
47 | #define spin_lock_prefetch(x) prefetchw(x) | |
48 | #endif | |
49 | ||
50 | #ifndef PREFETCH_STRIDE | |
51 | #define PREFETCH_STRIDE (4*L1_CACHE_BYTES) | |
52 | #endif | |
53 | ||
54 | static inline void prefetch_range(void *addr, size_t len) | |
55 | { | |
56 | #ifdef ARCH_HAS_PREFETCH | |
57 | char *cp; | |
58 | char *end = addr + len; | |
59 | ||
60 | for (cp = addr; cp < end; cp += PREFETCH_STRIDE) | |
61 | prefetch(cp); | |
62 | #endif | |
63 | } | |
64 | ||
65 | #endif |