[MIPS] Fix aliasing bug in copy_user_highpage, take 2.
Turns out b868868ae0
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>
This commit is contained in:
parent
736fad17b8
commit
985c30ef4d
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@ -211,7 +211,7 @@ void copy_user_highpage(struct page *to, struct page *from,
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void *vfrom, *vto;
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vto = kmap_atomic(to, KM_USER1);
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if (cpu_has_dc_aliases && !Page_dcache_dirty(from)) {
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if (cpu_has_dc_aliases && page_mapped(from)) {
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vfrom = kmap_coherent(from, vaddr);
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copy_page(vto, vfrom);
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kunmap_coherent();
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@ -234,12 +234,15 @@ void copy_to_user_page(struct vm_area_struct *vma,
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struct page *page, unsigned long vaddr, void *dst, const void *src,
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unsigned long len)
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{
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if (cpu_has_dc_aliases) {
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if (cpu_has_dc_aliases && page_mapped(page)) {
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void *vto = kmap_coherent(page, vaddr) + (vaddr & ~PAGE_MASK);
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memcpy(vto, src, len);
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kunmap_coherent();
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} else
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} else {
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memcpy(dst, src, len);
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if (cpu_has_dc_aliases)
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SetPageDcacheDirty(page);
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}
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if ((vma->vm_flags & VM_EXEC) && !cpu_has_ic_fills_f_dc)
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flush_cache_page(vma, vaddr, page_to_pfn(page));
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}
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@ -250,13 +253,15 @@ void copy_from_user_page(struct vm_area_struct *vma,
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struct page *page, unsigned long vaddr, void *dst, const void *src,
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unsigned long len)
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{
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if (cpu_has_dc_aliases) {
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void *vfrom =
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kmap_coherent(page, vaddr) + (vaddr & ~PAGE_MASK);
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if (cpu_has_dc_aliases && page_mapped(page)) {
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void *vfrom = kmap_coherent(page, vaddr) + (vaddr & ~PAGE_MASK);
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memcpy(dst, vfrom, len);
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kunmap_coherent();
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} else
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} else {
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memcpy(dst, src, len);
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if (cpu_has_dc_aliases)
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SetPageDcacheDirty(page);
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}
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}
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EXPORT_SYMBOL(copy_from_user_page);
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