From owner-p4-projects@FreeBSD.ORG Fri Sep 6 11:06:25 2013 Return-Path: Delivered-To: p4-projects@freebsd.org Received: by hub.freebsd.org (Postfix, from userid 32767) id 69F5226F; Fri, 6 Sep 2013 11:06:25 +0000 (UTC) Delivered-To: perforce@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [8.8.178.115]) (using TLSv1 with cipher ADH-AES256-SHA (256/256 bits)) (No client certificate requested) by hub.freebsd.org (Postfix) with ESMTP id 2BCC826D for ; Fri, 6 Sep 2013 11:06:25 +0000 (UTC) (envelope-from bb+lists.freebsd.perforce@cyrus.watson.org) Received: from skunkworks.freebsd.org (skunkworks.freebsd.org [8.8.178.74]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mx1.freebsd.org (Postfix) with ESMTPS id 184632205 for ; Fri, 6 Sep 2013 11:06:25 +0000 (UTC) Received: from skunkworks.freebsd.org ([127.0.1.74]) by skunkworks.freebsd.org (8.14.7/8.14.7) with ESMTP id r86B6Onj039208 for ; Fri, 6 Sep 2013 11:06:24 GMT (envelope-from bb+lists.freebsd.perforce@cyrus.watson.org) Received: (from perforce@localhost) by skunkworks.freebsd.org (8.14.7/8.14.6/Submit) id r86B6O6i039173 for perforce@freebsd.org; Fri, 6 Sep 2013 11:06:24 GMT (envelope-from bb+lists.freebsd.perforce@cyrus.watson.org) Date: Fri, 6 Sep 2013 11:06:24 GMT Message-Id: <201309061106.r86B6O6i039173@skunkworks.freebsd.org> X-Authentication-Warning: skunkworks.freebsd.org: perforce set sender to bb+lists.freebsd.perforce@cyrus.watson.org using -f From: Robert Watson Subject: PERFORCE change 601761 for review To: Perforce Change Reviews Precedence: bulk X-BeenThere: p4-projects@freebsd.org X-Mailman-Version: 2.1.14 List-Id: p4 projects tree changes List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 06 Sep 2013 11:06:25 -0000 http://p4web.freebsd.org/@@601761?ac=10 Change 601761 by rwatson@rwatson_zenith_cl_cam_ac_uk on 2013/09/06 11:05:45 Fixes to the CHERI CCall/CReturn stub exception handler: (1) Set noorder -- exception handlers with NOPs semi-arbitrarily inserted and removed work less well. (2) No need to ifdef CHERI exception handling paths -- this is definitely compiled only for CHERI. (3) Insert several NOPs after modifying EPC to ensure the new value is in place before ERET. The no-op CCall/CReturn handler now appears to be a no-op, rather than a recipe for segfaults. Affected files ... .. //depot/projects/ctsrd/cheribsd/src/bin/cheritest/cheritest.c#13 edit .. //depot/projects/ctsrd/cheribsd/src/sys/mips/cheri/ccall.S#3 edit Differences ... ==== //depot/projects/ctsrd/cheribsd/src/bin/cheritest/cheritest.c#13 (text+ko) ==== ==== //depot/projects/ctsrd/cheribsd/src/sys/mips/cheri/ccall.S#3 (text+ko) ==== @@ -43,6 +43,8 @@ #include "assym.s" + .set noreorder /* Preserve nops, allow instructions in b-d slots. */ + /* * Software implementations of CCall, CReturn handlers for CHERI. * @@ -51,18 +53,15 @@ VECTOR(CHERICCallVector, unknown) .set push .set noat -#ifdef CPU_CHERI CHERI_EXCEPTION_ENTER(k0) -#endif /* XXXRW: For now, increment PC as though it were a no-op. */ MFC0 k0, MIPS_COP_0_EXC_PC PTR_ADDU k0, 4 MTC0 k0, MIPS_COP_0_EXC_PC + COP0_SYNC -#ifdef CPU_CHERI CHERI_EXCEPTION_RETURN(k0) -#endif eret .set pop VECTOR_END(CHERICCallVector)