From owner-svn-src-all@freebsd.org Wed Jun 26 21:43:42 2019 Return-Path: Delivered-To: svn-src-all@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id 637C715D2F6B; Wed, 26 Jun 2019 21:43:42 +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 06CF489354; Wed, 26 Jun 2019 21:43:42 +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 D67115EFF; Wed, 26 Jun 2019 21:43:41 +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 x5QLhfjR015005; Wed, 26 Jun 2019 21:43:41 GMT (envelope-from alc@FreeBSD.org) Received: (from alc@localhost) by repo.freebsd.org (8.15.2/8.15.2/Submit) id x5QLhf6u015004; Wed, 26 Jun 2019 21:43:41 GMT (envelope-from alc@FreeBSD.org) Message-Id: <201906262143.x5QLhf6u015004@repo.freebsd.org> X-Authentication-Warning: repo.freebsd.org: alc set sender to alc@FreeBSD.org using -f From: Alan Cox Date: Wed, 26 Jun 2019 21:43:41 +0000 (UTC) To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r349442 - head/sys/arm64/arm64 X-SVN-Group: head X-SVN-Commit-Author: alc X-SVN-Commit-Paths: head/sys/arm64/arm64 X-SVN-Commit-Revision: 349442 X-SVN-Commit-Repository: base MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-Rspamd-Queue-Id: 06CF489354 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(-1.00)[-0.999,0]; NEURAL_HAM_SHORT(-0.97)[-0.965,0]; NEURAL_HAM_LONG(-1.00)[-1.000,0]; ASN(0.00)[asn:11403, ipnet:2610:1c1:1::/48, country:US] X-BeenThere: svn-src-all@freebsd.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: "SVN commit messages for the entire src tree \(except for " user" and " projects" \)" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 26 Jun 2019 21:43:42 -0000 Author: alc Date: Wed Jun 26 21:43:41 2019 New Revision: 349442 URL: https://svnweb.freebsd.org/changeset/base/349442 Log: Revert one of the changes from r349323. Specifically, undo the change that replaced a pmap_invalidate_page() with a dsb(ishst) in pmap_enter_quick_locked(). Even though this change is in principle correct, I am seeing occasional, spurious bus errors that are only reproducible without this pmap_invalidate_page(). (None of adding an isb, "upgrading" the dsb to wait on loads as well as stores, or disabling superpage mappings eliminates the bus errors.) Add an XXX comment explaining why the pmap_invalidate_page() is being performed. Discussed with: andrew, markj Modified: head/sys/arm64/arm64/pmap.c Modified: head/sys/arm64/arm64/pmap.c ============================================================================== --- head/sys/arm64/arm64/pmap.c Wed Jun 26 21:19:43 2019 (r349441) +++ head/sys/arm64/arm64/pmap.c Wed Jun 26 21:43:41 2019 (r349442) @@ -3758,7 +3758,15 @@ pmap_enter_quick_locked(pmap_t pmap, vm_offset_t va, v cpu_icache_sync_range(PHYS_TO_DMAP(pa), PAGE_SIZE); pmap_load_store(l3, l3_val); - dsb(ishst); + + /* + * XXX In principle, because this L3 entry was invalid, we should not + * need to perform a TLB invalidation here. However, in practice, + * when simply performing a "dsb ishst" here, processes are being + * terminated due to bus errors and segmentation violations. + */ + pmap_invalidate_page(pmap, va); + return (mpte); }