This patch implements THP shadow stack memory copying in the same way as the previous patch for regular PTE.
In copy_huge_pmd(), we clear the dirty bit from the PMD. On the next shadow stack access to the PMD, a page fault occurs. At that time, the page is copied/re-used and the PMD is fixed. Signed-off-by: Yu-cheng Yu <[email protected]> --- mm/huge_memory.c | 10 +++++++++- mm/hugetlb.c | 2 +- 2 files changed, 10 insertions(+), 2 deletions(-) diff --git a/mm/huge_memory.c b/mm/huge_memory.c index a3a1815f8e11..c6e72ccc4274 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -600,6 +600,8 @@ static int __do_huge_pmd_anonymous_page(struct vm_fault *vmf, struct page *page, entry = mk_huge_pmd(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); page_add_new_anon_rmap(page, vma, haddr, true); mem_cgroup_commit_charge(page, memcg, false, true); lru_cache_add_active_or_unevictable(page, vma); @@ -976,7 +978,7 @@ int copy_huge_pmd(struct mm_struct *dst_mm, struct mm_struct *src_mm, mm_inc_nr_ptes(dst_mm); pgtable_trans_huge_deposit(dst_mm, dst_pmd, pgtable); - pmdp_set_wrprotect(src_mm, addr, src_pmd); + pmdp_set_wrprotect_flush(vma, addr, src_pmd); pmd = pmd_mkold(pmd_wrprotect(pmd)); set_pmd_at(dst_mm, addr, dst_pmd, pmd); @@ -1196,6 +1198,8 @@ static int do_huge_pmd_wp_page_fallback(struct vm_fault *vmf, pmd_t orig_pmd, pte_t entry; entry = mk_pte(pages[i], vma->vm_page_prot); entry = maybe_mkwrite(pte_mkdirty(entry), vma); + if (is_shstk_mapping(vma->vm_flags)) + entry = pte_mkdirty_shstk(entry); memcg = (void *)page_private(pages[i]); set_page_private(pages[i], 0); page_add_new_anon_rmap(pages[i], vmf->vma, haddr, false); @@ -1280,6 +1284,8 @@ int do_huge_pmd_wp_page(struct vm_fault *vmf, pmd_t orig_pmd) pmd_t entry; entry = pmd_mkyoung(orig_pmd); entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma); + if (is_shstk_mapping(vma->vm_flags)) + entry = pmd_mkdirty_shstk(entry); if (pmdp_set_access_flags(vma, haddr, vmf->pmd, entry, 1)) update_mmu_cache_pmd(vma, vmf->address, vmf->pmd); ret |= VM_FAULT_WRITE; @@ -1350,6 +1356,8 @@ 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); pmdp_huge_clear_flush_notify(vma, haddr, vmf->pmd); page_add_new_anon_rmap(new_page, vma, haddr, true); mem_cgroup_commit_charge(new_page, memcg, false, true); diff --git a/mm/hugetlb.c b/mm/hugetlb.c index 218679138255..d694cfab9f90 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -3293,7 +3293,7 @@ int copy_hugetlb_page_range(struct mm_struct *dst, struct mm_struct *src, * * See Documentation/vm/mmu_notifier.txt */ - huge_ptep_set_wrprotect(src, addr, src_pte); + huge_ptep_set_wrprotect_flush(vma, addr, src_pte); } entry = huge_ptep_get(src_pte); ptepage = pte_page(entry); -- 2.15.1
