[PATCH] MIPS: Fix COW D-cache aliasing on fork
Provide a custom copy_user_highpage() to deal with aliasing issues on
MIPS. It uses kmap_coherent() to map an user page for kernel with same
color. Rewrite copy_to_user_page() and copy_from_user_page() with the
new interfaces to avoid extra cache flushing.
The main part of this patch was originally written by Ralf Baechle;
Atushi Nemoto did the the debugging.
Signed-off-by: Atsushi Nemoto <anemo@mba.ocn.ne.jp>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/include/asm-mips/page.h b/include/asm-mips/page.h
index 0dc1a45..2f9e1a9 100644
--- a/include/asm-mips/page.h
+++ b/include/asm-mips/page.h
@@ -35,7 +35,6 @@
#ifndef __ASSEMBLY__
#include <linux/pfn.h>
-#include <asm/cpu-features.h>
#include <asm/io.h>
extern void clear_page(void * page);
@@ -61,16 +60,13 @@
flush_data_cache_page((unsigned long)addr);
}
-static inline void copy_user_page(void *vto, void *vfrom, unsigned long vaddr,
- struct page *to)
-{
- extern void (*flush_data_cache_page)(unsigned long addr);
+extern void copy_user_page(void *vto, void *vfrom, unsigned long vaddr,
+ struct page *to);
+struct vm_area_struct;
+extern void copy_user_highpage(struct page *to, struct page *from,
+ unsigned long vaddr, struct vm_area_struct *vma);
- copy_page(vto, vfrom);
- if (!cpu_has_ic_fills_f_dc ||
- pages_do_alias((unsigned long)vto, vaddr & PAGE_MASK))
- flush_data_cache_page((unsigned long)vto);
-}
+#define __HAVE_ARCH_COPY_USER_HIGHPAGE
/*
* These are used to make use of C type-checking..