Commit 7e01c949 authored by Paul Mundt's avatar Paul Mundt
Browse files

sh: Partial revert of copy/clear_user_highpage() optimizations. 



These still require more testing, so revert them for now. We keep the
off-by-1 in the fixmap colouring and drop the rest.

Signed-off-by: default avatarPaul Mundt <lethal@linux-sh.org>
parent 8144a7dd

arch/sh/mm/cache.c

+13 −53
Original line number Diff line number Diff line
@@ -46,18 +46,6 @@ static inline void cacheop_on_each_cpu(void (*func) (void *info), void *info, 
	preempt_enable();

}



/*

 * copy_to_user_page

 * @vma: vm_area_struct holding the pages

 * @page: struct page

 * @vaddr: user space address

 * @dst: address of page in kernel space (possibly from kmap)

 * @src: source address in kernel logical memory

 * @len: length of data in bytes (may be less than PAGE_SIZE)

 *

 * Copy data into the address space of a process other than the current

 * process (eg for ptrace).

 */

void copy_to_user_page(struct vm_area_struct *vma, struct page *page,

		       unsigned long vaddr, void *dst, const void *src,

		       unsigned long len)
@@ -93,49 +81,28 @@ void copy_from_user_page(struct vm_area_struct *vma, struct page *page, 
	}

}



/*

 * copy_user_highpage

 * @to: destination page

 * @from: source page

 * @vaddr: address of pages in user address space

 * @vma: vm_area_struct holding the pages

 *

 * This is used in COW implementation to copy data from page @from to

 * page @to. @from was previousl mapped at @vaddr, and @to will be.

 * As this is used only in the COW implementation, this means that the

 * source is unmodified, and so we don't have to worry about cache

 * aliasing on that side.

 */

#ifdef CONFIG_HIGHMEM

/*

 * If we ever have a real highmem system, this code will need fixing

 * (as will clear_user/clear_user_highmem), because the kmap potentitally

 * creates another alias risk.

 */

#error This code is broken with real HIGHMEM

#endif

void copy_user_highpage(struct page *to, struct page *from,

			unsigned long vaddr, struct vm_area_struct *vma)

{

	void *vfrom, *vto;



	vto = kmap_atomic(to, KM_USER1);

	vfrom = kmap_atomic(from, KM_USER0);



	if (pages_do_alias((unsigned long)vto, vaddr & PAGE_MASK))

		__flush_invalidate_region(vto, PAGE_SIZE);



	if (boot_cpu_data.dcache.n_aliases && page_mapped(from) &&

	    !test_bit(PG_dcache_dirty, &from->flags)) {

		void *vto_coloured = kmap_coherent(to, vaddr);

		copy_page(vto_coloured, vfrom);

		kunmap_coherent(vto_coloured);

	} else

		vfrom = kmap_coherent(from, vaddr);

		copy_page(vto, vfrom);

		kunmap_coherent(vfrom);

	} else {

		vfrom = kmap_atomic(from, KM_USER0);

		copy_page(vto, vfrom);



		kunmap_atomic(vfrom, KM_USER0);

	kunmap_atomic(vto, KM_USER1);

	}



	if (pages_do_alias((unsigned long)vto, vaddr & PAGE_MASK))

		__flush_purge_region(vto, PAGE_SIZE);



	kunmap_atomic(vto, KM_USER1);

	/* Make sure this page is cleared on other CPU's too before using it */

	smp_wmb();

}
@@ -145,18 +112,11 @@ void clear_user_highpage(struct page *page, unsigned long vaddr) 
{

	void *kaddr = kmap_atomic(page, KM_USER0);



	if (pages_do_alias((unsigned long)kaddr, vaddr & PAGE_MASK)) {

		void *vto;



		/* Kernel alias may have modified data in the cache. */

		__flush_invalidate_region(kaddr, PAGE_SIZE);



		vto = kmap_coherent(page, vaddr);

		clear_page(vto);

		kunmap_coherent(vto);

	} else

	clear_page(kaddr);



	if (pages_do_alias((unsigned long)kaddr, vaddr & PAGE_MASK))

		__flush_purge_region(kaddr, PAGE_SIZE);



	kunmap_atomic(kaddr, KM_USER0);

}

EXPORT_SYMBOL(clear_user_highpage);