90 строки
2.0 KiB
C
90 строки
2.0 KiB
C
/* highmem.c: arch-specific highmem stuff
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*
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* Copyright (C) 2004 Red Hat, Inc. All Rights Reserved.
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* Written by David Howells (dhowells@redhat.com)
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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*/
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#include <linux/highmem.h>
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#include <linux/module.h>
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void *kmap(struct page *page)
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{
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might_sleep();
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if (!PageHighMem(page))
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return page_address(page);
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return kmap_high(page);
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}
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EXPORT_SYMBOL(kmap);
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void kunmap(struct page *page)
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{
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if (in_interrupt())
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BUG();
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if (!PageHighMem(page))
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return;
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kunmap_high(page);
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}
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EXPORT_SYMBOL(kunmap);
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struct page *kmap_atomic_to_page(void *ptr)
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{
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return virt_to_page(ptr);
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}
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void *kmap_atomic(struct page *page)
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{
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unsigned long paddr;
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int type;
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pagefault_disable();
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type = kmap_atomic_idx_push();
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paddr = page_to_phys(page);
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switch (type) {
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/*
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* The first 4 primary maps are reserved for architecture code
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*/
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case 0: return __kmap_atomic_primary(4, paddr, 6);
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case 1: return __kmap_atomic_primary(5, paddr, 7);
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case 2: return __kmap_atomic_primary(6, paddr, 8);
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case 3: return __kmap_atomic_primary(7, paddr, 9);
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case 4: return __kmap_atomic_primary(8, paddr, 10);
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case 5 ... 5 + NR_TLB_LINES - 1:
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return __kmap_atomic_secondary(type - 5, paddr);
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default:
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BUG();
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return NULL;
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}
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}
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EXPORT_SYMBOL(kmap_atomic);
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void __kunmap_atomic(void *kvaddr)
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{
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int type = kmap_atomic_idx();
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switch (type) {
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case 0: __kunmap_atomic_primary(4, 6); break;
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case 1: __kunmap_atomic_primary(5, 7); break;
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case 2: __kunmap_atomic_primary(6, 8); break;
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case 3: __kunmap_atomic_primary(7, 9); break;
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case 4: __kunmap_atomic_primary(8, 10); break;
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case 5 ... 5 + NR_TLB_LINES - 1:
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__kunmap_atomic_secondary(type - 5, kvaddr);
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break;
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default:
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BUG();
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}
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kmap_atomic_idx_pop();
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pagefault_enable();
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}
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EXPORT_SYMBOL(__kunmap_atomic);
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