From owner-svn-src-head@freebsd.org Mon Jul 29 21:21:54 2019 Return-Path: Delivered-To: svn-src-head@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 73E4CB6968; Mon, 29 Jul 2019 21:21:54 +0000 (UTC) (envelope-from markj@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 569256DE15; Mon, 29 Jul 2019 21:21:54 +0000 (UTC) (envelope-from markj@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 2CC166965; Mon, 29 Jul 2019 21:21:54 +0000 (UTC) (envelope-from markj@FreeBSD.org) Received: from repo.freebsd.org ([127.0.1.37]) by repo.freebsd.org (8.15.2/8.15.2) with ESMTP id x6TLLsnc022788; Mon, 29 Jul 2019 21:21:54 GMT (envelope-from markj@FreeBSD.org) Received: (from markj@localhost) by repo.freebsd.org (8.15.2/8.15.2/Submit) id x6TLLsiX022787; Mon, 29 Jul 2019 21:21:54 GMT (envelope-from markj@FreeBSD.org) Message-Id: <201907292121.x6TLLsiX022787@repo.freebsd.org> X-Authentication-Warning: repo.freebsd.org: markj set sender to markj@FreeBSD.org using -f From: Mark Johnston Date: Mon, 29 Jul 2019 21:21:54 +0000 (UTC) To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r350427 - head/sys/arm64/arm64 X-SVN-Group: head X-SVN-Commit-Author: markj X-SVN-Commit-Paths: head/sys/arm64/arm64 X-SVN-Commit-Revision: 350427 X-SVN-Commit-Repository: base MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-Rspamd-Queue-Id: 569256DE15 X-Spamd-Bar: -- Authentication-Results: mx1.freebsd.org X-Spamd-Result: default: False [-2.96 / 15.00]; local_wl_from(0.00)[FreeBSD.org]; NEURAL_HAM_MEDIUM(-0.99)[-0.994,0]; NEURAL_HAM_SHORT(-0.96)[-0.964,0]; ASN(0.00)[asn:11403, ipnet:2610:1c1:1::/48, country:US]; NEURAL_HAM_LONG(-1.00)[-1.000,0] X-BeenThere: svn-src-head@freebsd.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: SVN commit messages for the src tree for head/-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 29 Jul 2019 21:21:54 -0000 Author: markj Date: Mon Jul 29 21:21:53 2019 New Revision: 350427 URL: https://svnweb.freebsd.org/changeset/base/350427 Log: Have arm64's pmap_fault() handle WnR faults on dirty PTEs. If we take a WnR permission fault on a managed, writeable and dirty PTE, simply return success without calling the main fault handler. This situation can occur if multiple threads simultaneously access a clean writeable mapping and trigger WnR faults; losers of the race to mark the PTE dirty would end up calling the main fault handler, which had no work to do. Reported by: alc Reviewed by: alc MFC with: r350004 Sponsored by: The FreeBSD Foundation Differential Revision: https://reviews.freebsd.org/D21097 Modified: head/sys/arm64/arm64/pmap.c Modified: head/sys/arm64/arm64/pmap.c ============================================================================== --- head/sys/arm64/arm64/pmap.c Mon Jul 29 20:50:26 2019 (r350426) +++ head/sys/arm64/arm64/pmap.c Mon Jul 29 21:21:53 2019 (r350427) @@ -5743,7 +5743,7 @@ pmap_sync_icache(pmap_t pmap, vm_offset_t va, vm_size_ int pmap_fault(pmap_t pmap, uint64_t esr, uint64_t far) { - pt_entry_t *pte; + pt_entry_t pte, *ptep; register_t intr; uint64_t ec, par; int lvl, rv; @@ -5767,9 +5767,9 @@ pmap_fault(pmap_t pmap, uint64_t esr, uint64_t far) case ISS_DATA_DFSC_AFF_L2: case ISS_DATA_DFSC_AFF_L3: PMAP_LOCK(pmap); - pte = pmap_pte(pmap, far, &lvl); - if (pte != NULL) { - pmap_set_bits(pte, ATTR_AF); + ptep = pmap_pte(pmap, far, &lvl); + if (ptep != NULL) { + pmap_set_bits(ptep, ATTR_AF); rv = KERN_SUCCESS; /* * XXXMJ as an optimization we could mark the entry @@ -5785,12 +5785,13 @@ pmap_fault(pmap_t pmap, uint64_t esr, uint64_t far) (esr & ISS_DATA_WnR) == 0) return (rv); PMAP_LOCK(pmap); - pte = pmap_pte(pmap, far, &lvl); - if (pte != NULL && - (pmap_load(pte) & (ATTR_AP_RW_BIT | ATTR_SW_DBM)) == - (ATTR_AP(ATTR_AP_RO) | ATTR_SW_DBM)) { - pmap_clear_bits(pte, ATTR_AP_RW_BIT); - pmap_invalidate_page(pmap, far); + ptep = pmap_pte(pmap, far, &lvl); + if (ptep != NULL && + ((pte = pmap_load(ptep)) & ATTR_SW_DBM) != 0) { + if ((pte & ATTR_AP_RW_BIT) == ATTR_AP(ATTR_AP_RO)) { + pmap_clear_bits(ptep, ATTR_AP_RW_BIT); + pmap_invalidate_page(pmap, far); + } rv = KERN_SUCCESS; } PMAP_UNLOCK(pmap);