From owner-svn-src-all@freebsd.org Sat Sep 21 19:51:58 2019 Return-Path: Delivered-To: svn-src-all@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 724A512DDA1; Sat, 21 Sep 2019 19:51:58 +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 46bLnp2WTZz3wYk; Sat, 21 Sep 2019 19:51:58 +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 3AA011B432; Sat, 21 Sep 2019 19:51:58 +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 x8LJpwhp012347; Sat, 21 Sep 2019 19:51:58 GMT (envelope-from alc@FreeBSD.org) Received: (from alc@localhost) by repo.freebsd.org (8.15.2/8.15.2/Submit) id x8LJpwDd012346; Sat, 21 Sep 2019 19:51:58 GMT (envelope-from alc@FreeBSD.org) Message-Id: <201909211951.x8LJpwDd012346@repo.freebsd.org> X-Authentication-Warning: repo.freebsd.org: alc set sender to alc@FreeBSD.org using -f From: Alan Cox Date: Sat, 21 Sep 2019 19:51:58 +0000 (UTC) To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r352584 - 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: 352584 X-SVN-Commit-Repository: base MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 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: Sat, 21 Sep 2019 19:51:58 -0000 Author: alc Date: Sat Sep 21 19:51:57 2019 New Revision: 352584 URL: https://svnweb.freebsd.org/changeset/base/352584 Log: In case a translation fault on the kernel address space occurs from within a critical section, we must perform a lock-free check on the faulting address. Reported by: andrew Reviewed by: andrew, markj X-MFC with: r350579 Differential Revision: https://reviews.freebsd.org/D21685 Modified: head/sys/arm64/arm64/pmap.c Modified: head/sys/arm64/arm64/pmap.c ============================================================================== --- head/sys/arm64/arm64/pmap.c Sat Sep 21 19:05:38 2019 (r352583) +++ head/sys/arm64/arm64/pmap.c Sat Sep 21 19:51:57 2019 (r352584) @@ -5810,23 +5810,33 @@ pmap_fault(pmap_t pmap, uint64_t esr, uint64_t far) case ISS_DATA_DFSC_TF_L1: case ISS_DATA_DFSC_TF_L2: case ISS_DATA_DFSC_TF_L3: - PMAP_LOCK(pmap); - /* Ask the MMU to check the address */ - intr = intr_disable(); - if (pmap == kernel_pmap) - par = arm64_address_translate_s1e1r(far); - else - par = arm64_address_translate_s1e0r(far); - intr_restore(intr); - PMAP_UNLOCK(pmap); - /* - * If the translation was successful the address was invalid - * due to a break-before-make sequence. We can unlock and - * return success to the trap handler. + * Retry the translation. A break-before-make sequence can + * produce a transient fault. */ - if (PAR_SUCCESS(par)) - rv = KERN_SUCCESS; + if (pmap == kernel_pmap) { + /* + * The translation fault may have occurred within a + * critical section. Therefore, we must check the + * address without acquiring the kernel pmap's lock. + */ + if (pmap_kextract(far) != 0) + rv = KERN_SUCCESS; + } else { + PMAP_LOCK(pmap); + /* Ask the MMU to check the address. */ + intr = intr_disable(); + par = arm64_address_translate_s1e0r(far); + intr_restore(intr); + PMAP_UNLOCK(pmap); + + /* + * If the translation was successful, then we can + * return success to the trap handler. + */ + if (PAR_SUCCESS(par)) + rv = KERN_SUCCESS; + } break; }