From mboxrd@z Thu Jan 1 00:00:00 1970 From: catalin.marinas@arm.com (Catalin Marinas) Date: Thu, 20 May 2010 15:30:15 +0100 Subject: [PATCH 3/4] ARM: Assume new page cache pages have dirty D-cache In-Reply-To: <20100520142715.22202.33516.stgit@e102109-lin.cambridge.arm.com> References: <20100520142715.22202.33516.stgit@e102109-lin.cambridge.arm.com> Message-ID: <20100520143015.22202.47637.stgit@e102109-lin.cambridge.arm.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org 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(). Signed-off-by: Catalin Marinas --- arch/arm/include/asm/cacheflush.h | 6 +++--- arch/arm/include/asm/tlbflush.h | 2 +- arch/arm/mm/copypage-v4mc.c | 2 +- arch/arm/mm/copypage-v6.c | 2 +- arch/arm/mm/copypage-xscale.c | 2 +- arch/arm/mm/dma-mapping.c | 6 ++++++ arch/arm/mm/fault-armv.c | 4 ++-- arch/arm/mm/flush.c | 2 +- 8 files changed, 16 insertions(+), 10 deletions(-) diff --git a/arch/arm/include/asm/cacheflush.h b/arch/arm/include/asm/cacheflush.h index 4656a24..d3730f0 100644 --- a/arch/arm/include/asm/cacheflush.h +++ b/arch/arm/include/asm/cacheflush.h @@ -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 diff --git a/arch/arm/include/asm/tlbflush.h b/arch/arm/include/asm/tlbflush.h index bd863d8..40a7092 100644 --- a/arch/arm/include/asm/tlbflush.h +++ b/arch/arm/include/asm/tlbflush.h @@ -552,7 +552,7 @@ 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. */ diff --git a/arch/arm/mm/copypage-v4mc.c b/arch/arm/mm/copypage-v4mc.c index 598c51a..b806151 100644 --- a/arch/arm/mm/copypage-v4mc.c +++ b/arch/arm/mm/copypage-v4mc.c @@ -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); diff --git a/arch/arm/mm/copypage-v6.c b/arch/arm/mm/copypage-v6.c index f55fa10..bdba6c6 100644 --- a/arch/arm/mm/copypage-v6.c +++ b/arch/arm/mm/copypage-v6.c @@ -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 */ diff --git a/arch/arm/mm/copypage-xscale.c b/arch/arm/mm/copypage-xscale.c index 9920c0a..649bbcd 100644 --- a/arch/arm/mm/copypage-xscale.c +++ b/arch/arm/mm/copypage-xscale.c @@ -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); diff --git a/arch/arm/mm/dma-mapping.c b/arch/arm/mm/dma-mapping.c index 13fa536..bb9b612 100644 --- a/arch/arm/mm/dma-mapping.c +++ b/arch/arm/mm/dma-mapping.c @@ -508,6 +508,12 @@ 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) + set_bit(PG_dcache_clean, &page->flags); } EXPORT_SYMBOL(___dma_page_dev_to_cpu); diff --git a/arch/arm/mm/fault-armv.c b/arch/arm/mm/fault-armv.c index 9d77d90..91a691f 100644 --- a/arch/arm/mm/fault-armv.c +++ b/arch/arm/mm/fault-armv.c @@ -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 @@ -168,7 +168,7 @@ void update_mmu_cache(struct vm_area_struct *vma, unsigned long addr, return; mapping = page_mapping(page); - 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); if (mapping) { if (cache_is_vivt()) diff --git a/arch/arm/mm/flush.c b/arch/arm/mm/flush.c index 5ad8711..5abab9a 100644 --- a/arch/arm/mm/flush.c +++ b/arch/arm/mm/flush.c @@ -245,7 +245,7 @@ void flush_dcache_page(struct page *page) if (!cache_ops_need_broadcast() && !PageHighMem(page) && mapping && !mapping_mapped(mapping)) - set_bit(PG_dcache_dirty, &page->flags); + clear_bit(PG_dcache_clean, &page->flags); else { __flush_dcache_page(mapping, page); if (mapping && cache_is_vivt())