ARM: 6379/1: Assume new page cache pages have dirty D-cache

There are places in Linux where writes to newly allocated page cache
pages happen without a subsequent call to flush_dcache_page() (several
PIO drivers including USB HCD). This patch changes the meaning of
PG_arch_1 to be PG_dcache_clean and always flush the D-cache for a newly
mapped page in update_mmu_cache().

The patch also sets the PG_arch_1 bit in the DMA cache maintenance
function to avoid additional cache flushing in update_mmu_cache().

Tested-by: Rabin Vincent <rabin.vincent@stericsson.com>
Cc: Nicolas Pitre <nicolas.pitre@linaro.org>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
This commit is contained in:
Catalin Marinas 2010-09-13 15:57:36 +01:00 committed by Russell King
parent 0fc73099dd
commit c01778001a
8 changed files with 17 additions and 10 deletions

View file

@ -137,10 +137,10 @@
#endif
/*
* This flag is used to indicate that the page pointed to by a pte
* is dirty and requires cleaning before returning it to the user.
* This flag is used to indicate that the page pointed to by a pte is clean
* and does not require cleaning before returning it to the user.
*/
#define PG_dcache_dirty PG_arch_1
#define PG_dcache_clean PG_arch_1
/*
* MM Cache Management

View file

@ -560,7 +560,7 @@ extern void flush_tlb_kernel_range(unsigned long start, unsigned long end);
#endif
/*
* if PG_dcache_dirty is set for the page, we need to ensure that any
* If PG_dcache_clean is not set for the page, we need to ensure that any
* cache entries for the kernels virtual memory range are written
* back to the page.
*/

View file

@ -73,7 +73,7 @@ void v4_mc_copy_user_highpage(struct page *to, struct page *from,
{
void *kto = kmap_atomic(to, KM_USER1);
if (test_and_clear_bit(PG_dcache_dirty, &from->flags))
if (!test_and_set_bit(PG_dcache_clean, &from->flags))
__flush_dcache_page(page_mapping(from), from);
spin_lock(&minicache_lock);

View file

@ -79,7 +79,7 @@ static void v6_copy_user_highpage_aliasing(struct page *to,
unsigned int offset = CACHE_COLOUR(vaddr);
unsigned long kfrom, kto;
if (test_and_clear_bit(PG_dcache_dirty, &from->flags))
if (!test_and_set_bit(PG_dcache_clean, &from->flags))
__flush_dcache_page(page_mapping(from), from);
/* FIXME: not highmem safe */

View file

@ -95,7 +95,7 @@ void xscale_mc_copy_user_highpage(struct page *to, struct page *from,
{
void *kto = kmap_atomic(to, KM_USER1);
if (test_and_clear_bit(PG_dcache_dirty, &from->flags))
if (!test_and_set_bit(PG_dcache_clean, &from->flags))
__flush_dcache_page(page_mapping(from), from);
spin_lock(&minicache_lock);

View file

@ -523,6 +523,12 @@ void ___dma_page_dev_to_cpu(struct page *page, unsigned long off,
outer_inv_range(paddr, paddr + size);
dma_cache_maint_page(page, off, size, dir, dmac_unmap_area);
/*
* Mark the D-cache clean for this page to avoid extra flushing.
*/
if (dir != DMA_TO_DEVICE && off == 0 && size >= PAGE_SIZE)
set_bit(PG_dcache_clean, &page->flags);
}
EXPORT_SYMBOL(___dma_page_dev_to_cpu);

View file

@ -141,7 +141,7 @@ make_coherent(struct address_space *mapping, struct vm_area_struct *vma,
* a page table, or changing an existing PTE. Basically, there are two
* things that we need to take care of:
*
* 1. If PG_dcache_dirty is set for the page, we need to ensure
* 1. If PG_dcache_clean is not set for the page, we need to ensure
* that any cache entries for the kernels virtual memory
* range are written back to the page.
* 2. If we have multiple shared mappings of the same space in
@ -169,7 +169,7 @@ void update_mmu_cache(struct vm_area_struct *vma, unsigned long addr,
mapping = page_mapping(page);
#ifndef CONFIG_SMP
if (test_and_clear_bit(PG_dcache_dirty, &page->flags))
if (!test_and_set_bit(PG_dcache_clean, &page->flags))
__flush_dcache_page(mapping, page);
#endif
if (mapping) {

View file

@ -248,7 +248,7 @@ void flush_dcache_page(struct page *page)
#ifndef CONFIG_SMP
if (mapping && !mapping_mapped(mapping))
set_bit(PG_dcache_dirty, &page->flags);
clear_bit(PG_dcache_clean, &page->flags);
else
#endif
{
@ -257,6 +257,7 @@ void flush_dcache_page(struct page *page)
__flush_dcache_aliases(mapping, page);
else if (mapping)
__flush_icache_all();
set_bit(PG_dcache_clean, &page->flags);
}
}
EXPORT_SYMBOL(flush_dcache_page);