Re: [RFC PATCH v2 14/27] mm: Handle THP/HugeTLB shadow stack page fault

[Dave Hansen]

On 07/10/2018 03:26 PM, Yu-cheng Yu wrote:
> @@ -1347,6 +1353,8 @@ int do_huge_pmd_wp_page(struct vm_fault *vmf, pmd_t orig_pmd)
>  		pmd_t entry;
>  		entry = mk_huge_pmd(new_page, vma->vm_page_prot);
>  		entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma);
> +		if (is_shstk_mapping(vma->vm_flags))
> +			entry = pmd_mkdirty_shstk(entry);

This pattern is repeated enough that it makes me wonder if we should
just be doing the shadowstack PTE creation in mk_huge_pmd() itself.

Or, should we just be setting the shadowstack pte bit combination in
vma->vm_page_prot so we don't have to go set it explicitly every time?