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| author | Ralf Baechle <ralf@linux-mips.org> | 2007-10-15 15:30:24 (GMT) |
|---|---|---|
| committer | Ralf Baechle <ralf@linux-mips.org> | 2007-10-16 17:23:49 (GMT) |
| commit | 985c30ef4d7c2a4f0e979a507a7e2f7f09b096c3 (patch) | |
| tree | 8f5a447adaa49b6efb7485e8b69b2743eca3ee4b /arch/mips/mm | |
| parent | 736fad17b89e5e718908abb76ae9bce210a9d5d4 (diff) | |
| download | linux-985c30ef4d7c2a4f0e979a507a7e2f7f09b096c3.tar.xz | |
[MIPS] Fix aliasing bug in copy_user_highpage, take 2.
Turns out b868868ae0f7272228c95cc760338ffe35bb739d wasn't quite right.
When called for a page that isn't marked dirty it would artificially
create an alias instead of doing the obvious thing and access the page
via KSEG0.
The same issue also exists in copy_to_user_page and copy_from_user_page
which was causing the machine to die under rare circumstances for example
when running ps if the BUG_ON() assertion added by the earlier fix was
getting triggered.
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Diffstat (limited to 'arch/mips/mm')
| -rw-r--r-- | arch/mips/mm/init.c | 19 |
1 files changed, 12 insertions, 7 deletions
diff --git a/arch/mips/mm/init.c b/arch/mips/mm/init.c index 5240432..110ee76 100644 --- a/arch/mips/mm/init.c +++ b/arch/mips/mm/init.c @@ -211,7 +211,7 @@ 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_dcache_dirty(from)) { + if (cpu_has_dc_aliases && page_mapped(from)) { vfrom = kmap_coherent(from, vaddr); copy_page(vto, vfrom); kunmap_coherent(); @@ -234,12 +234,15 @@ 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) { + if (cpu_has_dc_aliases && page_mapped(page)) { void *vto = kmap_coherent(page, vaddr) + (vaddr & ~PAGE_MASK); memcpy(vto, src, len); kunmap_coherent(); - } else + } else { memcpy(dst, src, len); + if (cpu_has_dc_aliases) + SetPageDcacheDirty(page); + } if ((vma->vm_flags & VM_EXEC) && !cpu_has_ic_fills_f_dc) flush_cache_page(vma, vaddr, page_to_pfn(page)); } @@ -250,13 +253,15 @@ 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) { - void *vfrom = - kmap_coherent(page, vaddr) + (vaddr & ~PAGE_MASK); + if (cpu_has_dc_aliases && page_mapped(page)) { + void *vfrom = kmap_coherent(page, vaddr) + (vaddr & ~PAGE_MASK); memcpy(dst, vfrom, len); kunmap_coherent(); - } else + } else { memcpy(dst, src, len); + if (cpu_has_dc_aliases) + SetPageDcacheDirty(page); + } } EXPORT_SYMBOL(copy_from_user_page); |