projects / deliverable / linux.git / blame
| Commit | Line | Data |
|---|---|---|
| 1da177e4 LT |
1 | /* |
| 2 | * linux/arch/arm/mm/flush.c | |
| 3 | * | |
| 4 | * Copyright (C) 1995-2002 Russell King | |
| 5 | * | |
| 6 | * This program is free software; you can redistribute it and/or modify | |
| 7 | * it under the terms of the GNU General Public License version 2 as | |
| 8 | * published by the Free Software Foundation. | |
| 9 | */ | |
| 10 | #include <linux/module.h> | |
| 11 | #include <linux/mm.h> | |
| 12 | #include <linux/pagemap.h> | |
| 13 | ||
| 14 | #include <asm/cacheflush.h> | |
| 15 | #include <asm/system.h> | |
| 16 | ||
| 17 | static void __flush_dcache_page(struct address_space *mapping, struct page *page) | |
| 18 | { | |
| 19 | struct mm_struct *mm = current->active_mm; | |
| 20 | struct vm_area_struct *mpnt; | |
| 21 | struct prio_tree_iter iter; | |
| 22 | pgoff_t pgoff; | |
| 23 | ||
| 24 | /* | |
| 25 | * Writeback any data associated with the kernel mapping of this | |
| 26 | * page. This ensures that data in the physical page is mutually | |
| 27 | * coherent with the kernels mapping. | |
| 28 | */ | |
| 29 | __cpuc_flush_dcache_page(page_address(page)); | |
| 30 | ||
| 31 | /* | |
| 32 | * If there's no mapping pointer here, then this page isn't | |
| 33 | * visible to userspace yet, so there are no cache lines | |
| 34 | * associated with any other aliases. | |
| 35 | */ | |
| 36 | if (!mapping) | |
| 37 | return; | |
| 38 | ||
| 39 | /* | |
| 40 | * There are possible user space mappings of this page: | |
| 41 | * - VIVT cache: we need to also write back and invalidate all user | |
| 42 | * data in the current VM view associated with this page. | |
| 43 | * - aliasing VIPT: we only need to find one mapping of this page. | |
| 44 | */ | |
| 45 | pgoff = page->index << (PAGE_CACHE_SHIFT - PAGE_SHIFT); | |
| 46 | ||
| 47 | flush_dcache_mmap_lock(mapping); | |
| 48 | vma_prio_tree_foreach(mpnt, &iter, &mapping->i_mmap, pgoff, pgoff) { | |
| 49 | unsigned long offset; | |
| 50 | ||
| 51 | /* | |
| 52 | * If this VMA is not in our MM, we can ignore it. | |
| 53 | */ | |
| 54 | if (mpnt->vm_mm != mm) | |
| 55 | continue; | |
| 56 | if (!(mpnt->vm_flags & VM_MAYSHARE)) | |
| 57 | continue; | |
| 58 | offset = (pgoff - mpnt->vm_pgoff) << PAGE_SHIFT; | |
| 59 | flush_cache_page(mpnt, mpnt->vm_start + offset, page_to_pfn(page)); | |
| 60 | if (cache_is_vipt()) | |
| 61 | break; | |
| 62 | } | |
| 63 | flush_dcache_mmap_unlock(mapping); | |
| 64 | } | |
| 65 | ||
| 66 | /* | |
| 67 | * Ensure cache coherency between kernel mapping and userspace mapping | |
| 68 | * of this page. | |
| 69 | * | |
| 70 | * We have three cases to consider: | |
| 71 | * - VIPT non-aliasing cache: fully coherent so nothing required. | |
| 72 | * - VIVT: fully aliasing, so we need to handle every alias in our | |
| 73 | * current VM view. | |
| 74 | * - VIPT aliasing: need to handle one alias in our current VM view. | |
| 75 | * | |
| 76 | * If we need to handle aliasing: | |
| 77 | * If the page only exists in the page cache and there are no user | |
| 78 | * space mappings, we can be lazy and remember that we may have dirty | |
| 79 | * kernel cache lines for later. Otherwise, we assume we have | |
| 80 | * aliasing mappings. | |
| 81 | */ | |
| 82 | void flush_dcache_page(struct page *page) | |
| 83 | { | |
| 84 | struct address_space *mapping = page_mapping(page); | |
| 85 | ||
| 86 | if (cache_is_vipt_nonaliasing()) | |
| 87 | return; | |
| 88 | ||
| 89 | if (mapping && !mapping_mapped(mapping)) | |
| 90 | set_bit(PG_dcache_dirty, &page->flags); | |
| 91 | else | |
| 92 | __flush_dcache_page(mapping, page); | |
| 93 | } | |
| 94 | EXPORT_SYMBOL(flush_dcache_page); |