/arch/arm/mm/flush.c
https://bitbucket.org/evzijst/gittest · C · 94 lines · 40 code · 10 blank · 44 comment · 8 complexity · 8273484219548c58e8b80507fc6eeb9f MD5 · raw file
- /*
- * linux/arch/arm/mm/flush.c
- *
- * Copyright (C) 1995-2002 Russell King
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License version 2 as
- * published by the Free Software Foundation.
- */
- #include <linux/module.h>
- #include <linux/mm.h>
- #include <linux/pagemap.h>
- #include <asm/cacheflush.h>
- #include <asm/system.h>
- static void __flush_dcache_page(struct address_space *mapping, struct page *page)
- {
- struct mm_struct *mm = current->active_mm;
- struct vm_area_struct *mpnt;
- struct prio_tree_iter iter;
- pgoff_t pgoff;
- /*
- * Writeback any data associated with the kernel mapping of this
- * page. This ensures that data in the physical page is mutually
- * coherent with the kernels mapping.
- */
- __cpuc_flush_dcache_page(page_address(page));
- /*
- * If there's no mapping pointer here, then this page isn't
- * visible to userspace yet, so there are no cache lines
- * associated with any other aliases.
- */
- if (!mapping)
- return;
- /*
- * There are possible user space mappings of this page:
- * - VIVT cache: we need to also write back and invalidate all user
- * data in the current VM view associated with this page.
- * - aliasing VIPT: we only need to find one mapping of this page.
- */
- pgoff = page->index << (PAGE_CACHE_SHIFT - PAGE_SHIFT);
- flush_dcache_mmap_lock(mapping);
- vma_prio_tree_foreach(mpnt, &iter, &mapping->i_mmap, pgoff, pgoff) {
- unsigned long offset;
- /*
- * If this VMA is not in our MM, we can ignore it.
- */
- if (mpnt->vm_mm != mm)
- continue;
- if (!(mpnt->vm_flags & VM_MAYSHARE))
- continue;
- offset = (pgoff - mpnt->vm_pgoff) << PAGE_SHIFT;
- flush_cache_page(mpnt, mpnt->vm_start + offset, page_to_pfn(page));
- if (cache_is_vipt())
- break;
- }
- flush_dcache_mmap_unlock(mapping);
- }
- /*
- * Ensure cache coherency between kernel mapping and userspace mapping
- * of this page.
- *
- * We have three cases to consider:
- * - VIPT non-aliasing cache: fully coherent so nothing required.
- * - VIVT: fully aliasing, so we need to handle every alias in our
- * current VM view.
- * - VIPT aliasing: need to handle one alias in our current VM view.
- *
- * If we need to handle aliasing:
- * If the page only exists in the page cache and there are no user
- * space mappings, we can be lazy and remember that we may have dirty
- * kernel cache lines for later. Otherwise, we assume we have
- * aliasing mappings.
- */
- void flush_dcache_page(struct page *page)
- {
- struct address_space *mapping = page_mapping(page);
- if (cache_is_vipt_nonaliasing())
- return;
- if (mapping && !mapping_mapped(mapping))
- set_bit(PG_dcache_dirty, &page->flags);
- else
- __flush_dcache_page(mapping, page);
- }
- EXPORT_SYMBOL(flush_dcache_page);