diff options
| author | Atsushi Nemoto <anemo@mba.ocn.ne.jp> | 2006-12-12 17:14:56 +0000 |
|---|---|---|
| committer | Linus Torvalds <torvalds@woody.osdl.org> | 2006-12-13 09:27:08 -0800 |
| commit | bcd022801ee514e28c32837f0b3ce18c775f1a7b (patch) | |
| tree | 6230fbec80e9f1c7580efa685ded26f638f81ef0 /arch/mips | |
| parent | 9de455b20705f36384a711d4a20bcf7ba1ab180b (diff) | |
[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>
Diffstat (limited to 'arch/mips')
| -rw-r--r-- | arch/mips/mm/init.c | 25 |
1 files changed, 25 insertions, 0 deletions
diff --git a/arch/mips/mm/init.c b/arch/mips/mm/init.c index ea2d15370bb7..30245c09d025 100644 --- a/arch/mips/mm/init.c +++ b/arch/mips/mm/init.c @@ -203,6 +203,31 @@ static inline void kunmap_coherent(struct page *page) 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) |