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73 lines
1.7 KiB
73 lines
1.7 KiB
/* SPDX-License-Identifier: GPL-2.0 */ |
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/* |
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* Generic cache management functions. Everything is arch-specific, |
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* but this header exists to make sure the defines/functions can be |
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* used in a generic way. |
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* |
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* 2000-11-13 Arjan van de Ven <[email protected]> |
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* |
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*/ |
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#ifndef _LINUX_PREFETCH_H |
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#define _LINUX_PREFETCH_H |
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#include <linux/types.h> |
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#include <asm/processor.h> |
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#include <asm/cache.h> |
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struct page; |
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/* |
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prefetch(x) attempts to pre-emptively get the memory pointed to |
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by address "x" into the CPU L1 cache. |
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prefetch(x) should not cause any kind of exception, prefetch(0) is |
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specifically ok. |
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prefetch() should be defined by the architecture, if not, the |
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#define below provides a no-op define. |
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There are 3 prefetch() macros: |
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prefetch(x) - prefetches the cacheline at "x" for read |
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prefetchw(x) - prefetches the cacheline at "x" for write |
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spin_lock_prefetch(x) - prefetches the spinlock *x for taking |
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there is also PREFETCH_STRIDE which is the architecure-preferred |
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"lookahead" size for prefetching streamed operations. |
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*/ |
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#ifndef ARCH_HAS_PREFETCH |
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#define prefetch(x) __builtin_prefetch(x) |
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#endif |
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#ifndef ARCH_HAS_PREFETCHW |
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#define prefetchw(x) __builtin_prefetch(x,1) |
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#endif |
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#ifndef ARCH_HAS_SPINLOCK_PREFETCH |
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#define spin_lock_prefetch(x) prefetchw(x) |
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#endif |
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#ifndef PREFETCH_STRIDE |
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#define PREFETCH_STRIDE (4*L1_CACHE_BYTES) |
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#endif |
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static inline void prefetch_range(void *addr, size_t len) |
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{ |
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#ifdef ARCH_HAS_PREFETCH |
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char *cp; |
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char *end = addr + len; |
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for (cp = addr; cp < end; cp += PREFETCH_STRIDE) |
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prefetch(cp); |
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#endif |
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} |
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static inline void prefetch_page_address(struct page *page) |
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{ |
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#if defined(WANT_PAGE_VIRTUAL) || defined(HASHED_PAGE_VIRTUAL) |
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prefetch(page); |
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#endif |
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} |
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#endif
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