[PATCH v29 17/32] mm: Fixup places that call pte_mkwrite() directly
From: Yu-cheng Yu <hidden>
Date: 2021-08-20 18:20:45
Also in:
linux-api, linux-arch, linux-mm, lkml
Subsystem:
memory management, memory management - core, memory management - memory policy and migration, memory management - thp (transparent huge page), memory mapping, the rest · Maintainers:
Andrew Morton, David Hildenbrand, Lorenzo Stoakes, Liam R. Howlett, 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 have 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(). Make the same changes to do_huge_pmd_numa_page(). - In change_pte_range(), pte_mkwrite() is called directly. Replace it with maybe_mkwrite(). Signed-off-by: Yu-cheng Yu <redacted> Reviewed-by: Kirill A. Shutemov <redacted> Cc: Kees Cook <redacted> --- v25: - Apply same changes to do_huge_pmd_numa_page() as to do_numa_page(). --- mm/huge_memory.c | 2 +- mm/memory.c | 5 ++--- mm/migrate.c | 3 +-- mm/mprotect.c | 2 +- 4 files changed, 5 insertions(+), 7 deletions(-)
diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index c8dd5913884e..b9a6fc7af693 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c@@ -1515,7 +1515,7 @@ vm_fault_t do_huge_pmd_numa_page(struct vm_fault *vmf) pmd = pmd_modify(oldpmd, vma->vm_page_prot); pmd = pmd_mkyoung(pmd); if (was_writable) - pmd = pmd_mkwrite(pmd); + pmd = maybe_pmd_mkwrite(pmd, vma); set_pmd_at(vma->vm_mm, haddr, vmf->pmd, pmd); update_mmu_cache_pmd(vma, vmf->address, vmf->pmd); spin_unlock(vmf->ptl);
diff --git a/mm/memory.c b/mm/memory.c
index 25fc46e87214..5f8a84c17fa6 100644
--- a/mm/memory.c
+++ b/mm/memory.c@@ -3781,8 +3781,7 @@ 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);
@@ -4416,7 +4415,7 @@ 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); pte_unmap_unlock(vmf->pte, vmf->ptl);
diff --git a/mm/migrate.c b/mm/migrate.c
index 7e240437e7d9..8c90eb4ab3b1 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c@@ -2794,8 +2794,7 @@ 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 883e2cc85cad..9b424f2fd3a9 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