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Peter Anvin" , Thomas Gleixner , Ingo Molnar , linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org, linux-mm@kvack.org, linux-arch@vger.kernel.org, linux-api@vger.kernel.org, Arnd Bergmann , Andy Lutomirski , Balbir Singh , Borislav Petkov , Cyrill Gorcunov , Dave Hansen , Eugene Syromiatnikov , Florian Weimer , "H.J. Lu" , Jann Horn , Jonathan Corbet , Kees Cook , Mike Kravetz , Nadav Amit , Oleg Nesterov , Pavel Machek , Peter Zijlstra , Randy Dunlap , "Ravi V. Shankar" , Vedvyas Shanbhogue , Dave Martin , Weijiang Yang , Pengfei Xu , Haitao Huang Cc: Yu-cheng Yu Subject: [PATCH v21 15/26] mm: Fixup places that call pte_mkwrite() directly Date: Wed, 17 Feb 2021 14:27:19 -0800 Message-Id: <20210217222730.15819-16-yu-cheng.yu@intel.com> X-Mailer: git-send-email 2.21.0 In-Reply-To: <20210217222730.15819-1-yu-cheng.yu@intel.com> References: <20210217222730.15819-1-yu-cheng.yu@intel.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: 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 direct= ly 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 wi= th 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 Reviewed-by: Kees Cook --- 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) =20 entry =3D mk_pte(page, vma->vm_page_prot); entry =3D pte_sw_mkyoung(entry); - if (vma->vm_flags & VM_WRITE) - entry =3D pte_mkwrite(pte_mkdirty(entry)); + entry =3D maybe_mkwrite(pte_mkdirty(entry), vma); =20 vmf->pte =3D 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 =3D pte_modify(old_pte, vma->vm_page_prot); pte =3D pte_mkyoung(pte); if (was_writable) - pte =3D pte_mkwrite(pte); + pte =3D maybe_mkwrite(pte, vma); ptep_modify_prot_commit(vma, vmf->address, vmf->pte, old_pte, pte); update_mmu_cache(vma, vmf->address, vmf->pte); =20 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 =3D mk_pte(page, vma->vm_page_prot); - if (vma->vm_flags & VM_WRITE) - entry =3D pte_mkwrite(pte_mkdirty(entry)); + entry =3D maybe_mkwrite(pte_mkdirty(entry), vma); } =20 ptep =3D 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 =3D pte_mkwrite(ptent); + ptent =3D maybe_mkwrite(ptent, vma); } ptep_modify_prot_commit(vma, addr, pte, oldpte, ptent); pages++; --=20 2.21.0