1 | /* SPDX-License-Identifier: GPL-2.0 */ |
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 | struct page; |
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 2 prefetch() macros: |
29 | |
30 | prefetch(x) - prefetches the cacheline at "x" for read |
31 | prefetchw(x) - prefetches the cacheline at "x" for write |
32 | |
33 | there is also PREFETCH_STRIDE which is the architecure-preferred |
34 | "lookahead" size for prefetching streamed operations. |
35 | |
36 | */ |
37 | |
38 | #ifndef ARCH_HAS_PREFETCH |
39 | #define prefetch(x) __builtin_prefetch(x) |
40 | #endif |
41 | |
42 | #ifndef ARCH_HAS_PREFETCHW |
43 | #define prefetchw(x) __builtin_prefetch(x,1) |
44 | #endif |
45 | |
46 | #ifndef PREFETCH_STRIDE |
47 | #define PREFETCH_STRIDE (4*L1_CACHE_BYTES) |
48 | #endif |
49 | |
50 | static inline void prefetch_range(void *addr, size_t len) |
51 | { |
52 | #ifdef ARCH_HAS_PREFETCH |
53 | char *cp; |
54 | char *end = addr + len; |
55 | |
56 | for (cp = addr; cp < end; cp += PREFETCH_STRIDE) |
57 | prefetch(cp); |
58 | #endif |
59 | } |
60 | |
61 | static inline void prefetch_page_address(struct page *page) |
62 | { |
63 | #if defined(WANT_PAGE_VIRTUAL) || defined(HASHED_PAGE_VIRTUAL) |
64 | prefetch(page); |
65 | #endif |
66 | } |
67 | |
68 | #endif |
69 | |