The patch titled
MIPS: Fix COW D-cache aliasing on fork
has been added to the -mm tree. Its filename is
mips-fix-cow-d-cache-aliasing-on-fork.patch
See http://www.zip.com.au/~akpm/linux/patches/stuff/added-to-mm.txt to find
out what to do about this
------------------------------------------------------
Subject: MIPS: Fix COW D-cache aliasing on fork
From: Atsushi Nemoto <anemo@xxxxxxxxxxxxx>
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@xxxxxxxxxxxxx>
Signed-off-by: Ralf Baechle <ralf@xxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxx>
---
arch/mips/mm/init.c | 25 +++++++++++++++++++++++++
include/asm-mips/page.h | 16 ++++++----------
2 files changed, 31 insertions(+), 10 deletions(-)
diff -puN arch/mips/mm/init.c~mips-fix-cow-d-cache-aliasing-on-fork arch/mips/mm/init.c
--- a/arch/mips/mm/init.c~mips-fix-cow-d-cache-aliasing-on-fork
+++ a/arch/mips/mm/init.c
@@ -203,6 +203,31 @@ static inline void kunmap_coherent(struc
preempt_check_resched();
}
+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);
+ if (cpu_has_dc_aliases) {
+ vfrom = kmap_coherent(from, vaddr);
+ copy_page(vto, vfrom);
+ kunmap_coherent(from);
+ } else {
+ vfrom = kmap_atomic(from, KM_USER0);
+ copy_page(vto, vfrom);
+ kunmap_atomic(vfrom, KM_USER0);
+ }
+ if (((vma->vm_flags & VM_EXEC) && !cpu_has_ic_fills_f_dc) ||
+ pages_do_alias((unsigned long)vto, vaddr & PAGE_MASK))
+ flush_data_cache_page((unsigned long)vto);
+ kunmap_atomic(vto, KM_USER1);
+ /* Make sure this page is cleared on other CPU's too before using it */
+ smp_wmb();
+}
+
+EXPORT_SYMBOL(copy_user_highpage);
+
void copy_to_user_page(struct vm_area_struct *vma,
struct page *page, unsigned long vaddr, void *dst, const void *src,
unsigned long len)
diff -puN include/asm-mips/page.h~mips-fix-cow-d-cache-aliasing-on-fork include/asm-mips/page.h
--- a/include/asm-mips/page.h~mips-fix-cow-d-cache-aliasing-on-fork
+++ a/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 @@ static inline void clear_user_page(void
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..
_
Patches currently in -mm which might be from anemo@xxxxxxxxxxxxx are
origin.patch
fix-cow-d-cache-aliasing-on-fork.patch
pass-vma-argument-to-copy_user_highpage.patch
mips-fix-cow-d-cache-aliasing-on-fork.patch
-
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