On Wed, Feb 03, 2021 at 02:55:32PM -0800, Yu-cheng Yu wrote: > The read-only and Dirty PTE has been used to indicate copy-on-write pages. > However, newer x86 processors also regard a read-only and Dirty PTE as a > shadow stack page. In order to separate the two, the software-defined > _PAGE_COW is created to replace _PAGE_DIRTY for the copy-on-write case, and > pte_*() are updated. > > Pte_modify() changes a PTE to 'newprot', but it doesn't use the pte_*(). > Introduce fixup_dirty_pte(), which sets a dirty PTE, based on _PAGE_RW, > to either _PAGE_DIRTY or _PAGE_COW. > > Apply the same changes to pmd_modify(). > > Signed-off-by: Yu-cheng Yu <yu-cheng.yu@xxxxxxxxx> Reviewed-by: Kees Cook <keescook@xxxxxxxxxxxx> -- Kees Cook
