sh: Assume new page cache pages have dirty dcache lines.

This follows the ARM change c0177800
("ARM: 6379/1: Assume new page cache pages have dirty D-cache") for the
same rationale:

    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().

This addresses issues seen with executing binaries from MMC, in
addition to some of the other HCDs that don't explicitly do cache
management for their pipe-in buffers.
Requested-by: NYoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Signed-off-by: NPaul Mundt <lethal@linux-sh.org>

arch/sh/include/asm/cacheflush.h

@@ -96,7 +96,7 @@ void kmap_coherent_init(void);
 void *kmap_coherent(struct page *page, unsigned long addr);
 void kunmap_coherent(void *kvaddr);
 
-#define PG_dcache_dirty	PG_arch_1
+#define PG_dcache_clean	PG_arch_1
 
 void cpu_cache_init(void);
 

arch/sh/mm/cache-sh4.c

@@ -114,7 +114,7 @@ static void sh4_flush_dcache_page(void *arg)
 	struct address_space *mapping = page_mapping(page);
 
 	if (mapping && !mapping_mapped(mapping))
-		set_bit(PG_dcache_dirty, &page->flags);
+		clear_bit(PG_dcache_clean, &page->flags);
 	else
 #endif
 		flush_cache_one(CACHE_OC_ADDRESS_ARRAY |
@@ -239,7 +239,7 @@ static void sh4_flush_cache_page(void *args)
 		 * another ASID than the current one.
 		 */
 		map_coherent = (current_cpu_data.dcache.n_aliases &&
-			!test_bit(PG_dcache_dirty, &page->flags) &&
+			test_bit(PG_dcache_clean, &page->flags) &&
 			page_mapped(page));
 		if (map_coherent)
 			vaddr = kmap_coherent(page, address);

arch/sh/mm/cache-sh7705.c

@@ -139,7 +139,7 @@ static void sh7705_flush_dcache_page(void *arg)
 	struct address_space *mapping = page_mapping(page);
 
 	if (mapping && !mapping_mapped(mapping))
-		set_bit(PG_dcache_dirty, &page->flags);
+		clear_bit(PG_dcache_clean, &page->flags);
 	else
 		__flush_dcache_page(__pa(page_address(page)));
 }

arch/sh/mm/cache.c

@@ -60,14 +60,14 @@ void copy_to_user_page(struct vm_area_struct *vma, struct page *page,
 		       unsigned long len)
 {
 	if (boot_cpu_data.dcache.n_aliases && page_mapped(page) &&
-	    !test_bit(PG_dcache_dirty, &page->flags)) {
+	    test_bit(PG_dcache_clean, &page->flags)) {
 		void *vto = kmap_coherent(page, vaddr) + (vaddr & ~PAGE_MASK);
 		memcpy(vto, src, len);
 		kunmap_coherent(vto);
 	} else {
 		memcpy(dst, src, len);
 		if (boot_cpu_data.dcache.n_aliases)
-			set_bit(PG_dcache_dirty, &page->flags);
+			clear_bit(PG_dcache_clean, &page->flags);
 	}
 
 	if (vma->vm_flags & VM_EXEC)
@@ -79,14 +79,14 @@ void copy_from_user_page(struct vm_area_struct *vma, struct page *page,
 			 unsigned long len)
 {
 	if (boot_cpu_data.dcache.n_aliases && page_mapped(page) &&
-	    !test_bit(PG_dcache_dirty, &page->flags)) {
+	    test_bit(PG_dcache_clean, &page->flags)) {
 		void *vfrom = kmap_coherent(page, vaddr) + (vaddr & ~PAGE_MASK);
 		memcpy(dst, vfrom, len);
 		kunmap_coherent(vfrom);
 	} else {
 		memcpy(dst, src, len);
 		if (boot_cpu_data.dcache.n_aliases)
-			set_bit(PG_dcache_dirty, &page->flags);
+			clear_bit(PG_dcache_clean, &page->flags);
 	}
 }
 
@@ -98,7 +98,7 @@ void copy_user_highpage(struct page *to, struct page *from,
 	vto = kmap_atomic(to, KM_USER1);
 
 	if (boot_cpu_data.dcache.n_aliases && page_mapped(from) &&
-	    !test_bit(PG_dcache_dirty, &from->flags)) {
+	    test_bit(PG_dcache_clean, &from->flags)) {
 		vfrom = kmap_coherent(from, vaddr);
 		copy_page(vto, vfrom);
 		kunmap_coherent(vfrom);
@@ -141,7 +141,7 @@ void __update_cache(struct vm_area_struct *vma,
 
 	page = pfn_to_page(pfn);
 	if (pfn_valid(pfn)) {
-		int dirty = test_and_clear_bit(PG_dcache_dirty, &page->flags);
+		int dirty = !test_and_set_bit(PG_dcache_clean, &page->flags);
 		if (dirty)
 			__flush_purge_region(page_address(page), PAGE_SIZE);
 	}
@@ -153,7 +153,7 @@ void __flush_anon_page(struct page *page, unsigned long vmaddr)
 
 	if (pages_do_alias(addr, vmaddr)) {
 		if (boot_cpu_data.dcache.n_aliases && page_mapped(page) &&
-		    !test_bit(PG_dcache_dirty, &page->flags)) {
+		    test_bit(PG_dcache_clean, &page->flags)) {
 			void *kaddr;
 
 			kaddr = kmap_coherent(page, vmaddr);

arch/sh/mm/kmap.c

@@ -34,7 +34,7 @@ void *kmap_coherent(struct page *page, unsigned long addr)
 	enum fixed_addresses idx;
 	unsigned long vaddr;
 
-	BUG_ON(test_bit(PG_dcache_dirty, &page->flags));
+	BUG_ON(!test_bit(PG_dcache_clean, &page->flags));
 
 	pagefault_disable();