On Wed, Dec 12, 2007 at 12:06:10PM +0000, Ralf Baechle wrote:
> > Call Trace:
> > [<ffffffff8801bcf0>] kmap_coherent+0x10/0x130
> > [<ffffffff8801c010>] copy_from_user_page+0x40/0xb0
> > [<ffffffff88079d10>] access_process_vm+0x168/0x1d8
> > [<ffffffff880d9014>] proc_pid_cmdline+0xac/0x140
> > [<ffffffff880db188>] proc_info_read+0x108/0x150
> > [<ffffffff8808fbdc>] vfs_read+0xec/0x178
> > [<ffffffff88090060>] sys_read+0x50/0x98
> > [<ffffffff88019718>] handle_sys+0x118/0x134
> >
> >
> > Code: 0002127a 00021000 30420001 <00028036> 8f820024 3c038843 24420001 af820024 dc62f390
>
> Hmm... This suggests that 283abbaef425c1bf817ecbb456c413cab08b1434 is
> not quite right. It is making the assumption that a mapped page never has
> PG_dcache_dirty set.
Totally untested because I have other stuff to do but something along the
lines of below patch, I think.
Ralf
diff --git a/arch/mips/mm/init.c b/arch/mips/mm/init.c
index 480dec0..db5d608 100644
--- a/arch/mips/mm/init.c
+++ b/arch/mips/mm/init.c
@@ -211,7 +211,8 @@ void copy_user_highpage(struct page *to, struct page *from,
void *vfrom, *vto;
vto = kmap_atomic(to, KM_USER1);
- if (cpu_has_dc_aliases && page_mapped(from)) {
+ if (cpu_has_dc_aliases &&
+ page_mapped(from) && !Page_dcache_dirty(from)) {
vfrom = kmap_coherent(from, vaddr);
copy_page(vto, vfrom);
kunmap_coherent();
@@ -234,7 +235,8 @@ void copy_to_user_page(struct vm_area_struct *vma,
struct page *page, unsigned long vaddr, void *dst, const void *src,
unsigned long len)
{
- if (cpu_has_dc_aliases && page_mapped(page)) {
+ if (cpu_has_dc_aliases &&
+ page_mapped(page) && !Page_dcache_dirty(from)) {
void *vto = kmap_coherent(page, vaddr) + (vaddr & ~PAGE_MASK);
memcpy(vto, src, len);
kunmap_coherent();
@@ -253,7 +255,8 @@ void copy_from_user_page(struct vm_area_struct *vma,
struct page *page, unsigned long vaddr, void *dst, const void *src,
unsigned long len)
{
- if (cpu_has_dc_aliases && page_mapped(page)) {
+ if (cpu_has_dc_aliases &&
+ page_mapped(page) && !Page_dcache_dirty(page)) {
void *vfrom = kmap_coherent(page, vaddr) + (vaddr & ~PAGE_MASK);
memcpy(dst, vfrom, len);
kunmap_coherent();
