From owner-svn-src-stable-12@freebsd.org Thu Sep 19 14:36:31 2019 Return-Path: Delivered-To: svn-src-stable-12@mailman.nyi.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mailman.nyi.freebsd.org (Postfix) with ESMTP id B01691250C2; Thu, 19 Sep 2019 14:36:31 +0000 (UTC) (envelope-from alc@FreeBSD.org) Received: from mxrelay.nyi.freebsd.org (mxrelay.nyi.freebsd.org [IPv6:2610:1c1:1:606c::19:3]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) server-signature RSA-PSS (4096 bits) client-signature RSA-PSS (4096 bits) client-digest SHA256) (Client CN "mxrelay.nyi.freebsd.org", Issuer "Let's Encrypt Authority X3" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 46Yztl3PZtz3KBd; Thu, 19 Sep 2019 14:36:31 +0000 (UTC) (envelope-from alc@FreeBSD.org) Received: from repo.freebsd.org (repo.freebsd.org [IPv6:2610:1c1:1:6068::e6a:0]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by mxrelay.nyi.freebsd.org (Postfix) with ESMTPS id 3ADEFEE2B; Thu, 19 Sep 2019 14:36:31 +0000 (UTC) (envelope-from alc@FreeBSD.org) Received: from repo.freebsd.org ([127.0.1.37]) by repo.freebsd.org (8.15.2/8.15.2) with ESMTP id x8JEaV6m011819; Thu, 19 Sep 2019 14:36:31 GMT (envelope-from alc@FreeBSD.org) Received: (from alc@localhost) by repo.freebsd.org (8.15.2/8.15.2/Submit) id x8JEaU8O011817; Thu, 19 Sep 2019 14:36:30 GMT (envelope-from alc@FreeBSD.org) Message-Id: <201909191436.x8JEaU8O011817@repo.freebsd.org> X-Authentication-Warning: repo.freebsd.org: alc set sender to alc@FreeBSD.org using -f From: Alan Cox Date: Thu, 19 Sep 2019 14:36:30 +0000 (UTC) To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-stable@freebsd.org, svn-src-stable-12@freebsd.org Subject: svn commit: r352517 - in stable/12/sys: amd64/amd64 i386/i386 X-SVN-Group: stable-12 X-SVN-Commit-Author: alc X-SVN-Commit-Paths: in stable/12/sys: amd64/amd64 i386/i386 X-SVN-Commit-Revision: 352517 X-SVN-Commit-Repository: base MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-BeenThere: svn-src-stable-12@freebsd.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: SVN commit messages for only the 12-stable src tree List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 19 Sep 2019 14:36:31 -0000 Author: alc Date: Thu Sep 19 14:36:30 2019 New Revision: 352517 URL: https://svnweb.freebsd.org/changeset/base/352517 Log: MFC r349526: When we protect PTEs (as opposed to PDEs), we only call vm_page_dirty() when, in fact, we are write protecting the page and the PTE has PG_M set. However, pmap_protect_pde() was always calling vm_page_dirty() when the PDE has PG_M set. So, adding PG_NX to a writeable PDE could result in unnecessary (but harmless) calls to vm_page_dirty(). Simplify the loop calling vm_page_dirty() in pmap_protect_pde(). Modified: stable/12/sys/amd64/amd64/pmap.c stable/12/sys/i386/i386/pmap.c Directory Properties: stable/12/ (props changed) Modified: stable/12/sys/amd64/amd64/pmap.c ============================================================================== --- stable/12/sys/amd64/amd64/pmap.c Thu Sep 19 13:25:19 2019 (r352516) +++ stable/12/sys/amd64/amd64/pmap.c Thu Sep 19 14:36:30 2019 (r352517) @@ -5214,8 +5214,7 @@ static boolean_t pmap_protect_pde(pmap_t pmap, pd_entry_t *pde, vm_offset_t sva, vm_prot_t prot) { pd_entry_t newpde, oldpde; - vm_offset_t eva, va; - vm_page_t m; + vm_page_t m, mt; boolean_t anychanged; pt_entry_t PG_G, PG_M, PG_RW; @@ -5229,15 +5228,15 @@ pmap_protect_pde(pmap_t pmap, pd_entry_t *pde, vm_offs anychanged = FALSE; retry: oldpde = newpde = *pde; - if ((oldpde & (PG_MANAGED | PG_M | PG_RW)) == - (PG_MANAGED | PG_M | PG_RW)) { - eva = sva + NBPDR; - for (va = sva, m = PHYS_TO_VM_PAGE(oldpde & PG_PS_FRAME); - va < eva; va += PAGE_SIZE, m++) - vm_page_dirty(m); - } - if ((prot & VM_PROT_WRITE) == 0) + if ((prot & VM_PROT_WRITE) == 0) { + if ((oldpde & (PG_MANAGED | PG_M | PG_RW)) == + (PG_MANAGED | PG_M | PG_RW)) { + m = PHYS_TO_VM_PAGE(oldpde & PG_PS_FRAME); + for (mt = m; mt < &m[NBPDR / PAGE_SIZE]; mt++) + vm_page_dirty(mt); + } newpde &= ~(PG_RW | PG_M); + } if ((prot & VM_PROT_EXECUTE) == 0) newpde |= pg_nx; if (newpde != oldpde) { Modified: stable/12/sys/i386/i386/pmap.c ============================================================================== --- stable/12/sys/i386/i386/pmap.c Thu Sep 19 13:25:19 2019 (r352516) +++ stable/12/sys/i386/i386/pmap.c Thu Sep 19 14:36:30 2019 (r352517) @@ -3332,8 +3332,7 @@ static boolean_t pmap_protect_pde(pmap_t pmap, pd_entry_t *pde, vm_offset_t sva, vm_prot_t prot) { pd_entry_t newpde, oldpde; - vm_offset_t eva, va; - vm_page_t m; + vm_page_t m, mt; boolean_t anychanged; PMAP_LOCK_ASSERT(pmap, MA_OWNED); @@ -3342,15 +3341,15 @@ pmap_protect_pde(pmap_t pmap, pd_entry_t *pde, vm_offs anychanged = FALSE; retry: oldpde = newpde = *pde; - if ((oldpde & (PG_MANAGED | PG_M | PG_RW)) == - (PG_MANAGED | PG_M | PG_RW)) { - eva = sva + NBPDR; - for (va = sva, m = PHYS_TO_VM_PAGE(oldpde & PG_PS_FRAME); - va < eva; va += PAGE_SIZE, m++) - vm_page_dirty(m); - } - if ((prot & VM_PROT_WRITE) == 0) + if ((prot & VM_PROT_WRITE) == 0) { + if ((oldpde & (PG_MANAGED | PG_M | PG_RW)) == + (PG_MANAGED | PG_M | PG_RW)) { + m = PHYS_TO_VM_PAGE(oldpde & PG_PS_FRAME); + for (mt = m; mt < &m[NBPDR / PAGE_SIZE]; mt++) + vm_page_dirty(mt); + } newpde &= ~(PG_RW | PG_M); + } #if defined(PAE) || defined(PAE_TABLES) if ((prot & VM_PROT_EXECUTE) == 0) newpde |= pg_nx;