[PATCH v21 15/26] mm: Fixup places that call pte_mkwrite() directly
From: Yu-cheng Yu <hidden>
Date: 2021-02-17 22:38:39
Also in:
linux-arch, linux-doc, linux-mm, lkml
Subsystem:
memory management, memory management - core, memory management - memory policy and migration, memory mapping, the rest · Maintainers:
Andrew Morton, David Hildenbrand, Liam R. Howlett, Lorenzo Stoakes, Linus Torvalds
When serving a page fault, maybe_mkwrite() makes a PTE writable if it is in a writable vma. A shadow stack vma is writable, but its PTEs need _PAGE_DIRTY to be set to become writable. For this reason, maybe_mkwrite() has been updated. There are a few places that call pte_mkwrite() directly, but effect the same result as from maybe_mkwrite(). These sites need to be updated for shadow stack as well. Thus, change them to maybe_mkwrite(): - do_anonymous_page() and migrate_vma_insert_page() check VM_WRITE directly and call pte_mkwrite(), which is the same as maybe_mkwrite(). Change them to maybe_mkwrite(). - In do_numa_page(), if the numa entry 'was-writable', then pte_mkwrite() is called directly. Fix it by doing maybe_mkwrite(). - In change_pte_range(), pte_mkwrite() is called directly. Replace it with maybe_mkwrite(). A shadow stack vma is writable but has different vma flags, and handled accordingly in maybe_mkwrite(). Signed-off-by: Yu-cheng Yu <redacted> Reviewed-by: Kees Cook <redacted> --- mm/memory.c | 5 ++--- mm/migrate.c | 3 +-- mm/mprotect.c | 2 +- 3 files changed, 4 insertions(+), 6 deletions(-)
diff --git a/mm/memory.c b/mm/memory.c
index feff48e1465a..1de649c61013 100644
--- a/mm/memory.c
+++ b/mm/memory.c@@ -3549,8 +3549,7 @@ static vm_fault_t do_anonymous_page(struct vm_fault *vmf) entry = mk_pte(page, vma->vm_page_prot); entry = pte_sw_mkyoung(entry); - if (vma->vm_flags & VM_WRITE) - entry = pte_mkwrite(pte_mkdirty(entry)); + entry = maybe_mkwrite(pte_mkdirty(entry), vma); vmf->pte = pte_offset_map_lock(vma->vm_mm, vmf->pmd, vmf->address, &vmf->ptl);
@@ -4205,7 +4204,7 @@ static vm_fault_t do_numa_page(struct vm_fault *vmf) pte = pte_modify(old_pte, vma->vm_page_prot); pte = pte_mkyoung(pte); if (was_writable) - pte = pte_mkwrite(pte); + pte = maybe_mkwrite(pte, vma); ptep_modify_prot_commit(vma, vmf->address, vmf->pte, old_pte, pte); update_mmu_cache(vma, vmf->address, vmf->pte);
diff --git a/mm/migrate.c b/mm/migrate.c
index 20ca887ea769..5c6b1a4c25a2 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c@@ -2970,8 +2970,7 @@ static void migrate_vma_insert_page(struct migrate_vma *migrate, } } else { entry = mk_pte(page, vma->vm_page_prot); - if (vma->vm_flags & VM_WRITE) - entry = pte_mkwrite(pte_mkdirty(entry)); + entry = maybe_mkwrite(pte_mkdirty(entry), vma); } ptep = pte_offset_map_lock(mm, pmdp, addr, &ptl);
diff --git a/mm/mprotect.c b/mm/mprotect.c
index ab709023e9aa..ed26e675c423 100644
--- a/mm/mprotect.c
+++ b/mm/mprotect.c@@ -135,7 +135,7 @@ static unsigned long change_pte_range(struct vm_area_struct *vma, pmd_t *pmd, if (dirty_accountable && pte_dirty(ptent) && (pte_soft_dirty(ptent) || !(vma->vm_flags & VM_SOFTDIRTY))) { - ptent = pte_mkwrite(ptent); + ptent = maybe_mkwrite(ptent, vma); } ptep_modify_prot_commit(vma, addr, pte, oldpte, ptent); pages++;
--
2.21.0