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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 | ||
1fa5cef2 | 18 | struct page; |
1da177e4 LT |
19 | /* |
20 | prefetch(x) attempts to pre-emptively get the memory pointed to | |
21 | by address "x" into the CPU L1 cache. | |
22 | prefetch(x) should not cause any kind of exception, prefetch(0) is | |
23 | specifically ok. | |
24 | ||
25 | prefetch() should be defined by the architecture, if not, the | |
26 | #define below provides a no-op define. | |
27 | ||
28 | There are 3 prefetch() macros: | |
29 | ||
30 | prefetch(x) - prefetches the cacheline at "x" for read | |
31 | prefetchw(x) - prefetches the cacheline at "x" for write | |
52161845 | 32 | spin_lock_prefetch(x) - prefetches the spinlock *x for taking |
1da177e4 | 33 | |
25985edc | 34 | there is also PREFETCH_STRIDE which is the architecure-preferred |
1da177e4 LT |
35 | "lookahead" size for prefetching streamed operations. |
36 | ||
37 | */ | |
38 | ||
1da177e4 | 39 | #ifndef ARCH_HAS_PREFETCH |
ab483570 | 40 | #define prefetch(x) __builtin_prefetch(x) |
1da177e4 LT |
41 | #endif |
42 | ||
43 | #ifndef ARCH_HAS_PREFETCHW | |
ab483570 | 44 | #define prefetchw(x) __builtin_prefetch(x,1) |
1da177e4 LT |
45 | #endif |
46 | ||
47 | #ifndef ARCH_HAS_SPINLOCK_PREFETCH | |
48 | #define spin_lock_prefetch(x) prefetchw(x) | |
49 | #endif | |
50 | ||
51 | #ifndef PREFETCH_STRIDE | |
52 | #define PREFETCH_STRIDE (4*L1_CACHE_BYTES) | |
53 | #endif | |
54 | ||
55 | static inline void prefetch_range(void *addr, size_t len) | |
56 | { | |
57 | #ifdef ARCH_HAS_PREFETCH | |
58 | char *cp; | |
59 | char *end = addr + len; | |
60 | ||
61 | for (cp = addr; cp < end; cp += PREFETCH_STRIDE) | |
62 | prefetch(cp); | |
63 | #endif | |
64 | } | |
65 | ||
1fa5cef2 LR |
66 | static inline void prefetch_page_address(struct page *page) |
67 | { | |
68 | #if defined(WANT_PAGE_VIRTUAL) || defined(HASHED_PAGE_VIRTUAL) | |
69 | prefetch(page); | |
70 | #endif | |
71 | } | |
72 | ||
1da177e4 | 73 | #endif |