Re: [RFC PATCH v2 14/27] mm: Handle THP/HugeTLB shadow stack page fault
From: Dave Hansen <dave.hansen@linux.intel.com>
Date: 2018-07-10 23:08:36
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On 07/10/2018 03:26 PM, Yu-cheng Yu wrote:
quoted hunk ↗ jump to hunk
@@ -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?