From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751375AbdIIXfs (ORCPT ); Sat, 9 Sep 2017 19:35:48 -0400 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:43076 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752905AbdIIXBJ (ORCPT ); Sat, 9 Sep 2017 19:01:09 -0400 Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit MIME-Version: 1.0 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org CC: akpm@linux-foundation.org, "Michael Neuling" , "Michael Ellerman" Date: Sat, 09 Sep 2017 22:47:14 +0100 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) Subject: [PATCH 3.16 068/233] selftests/powerpc: Fix TM resched DSCR test with some compilers In-Reply-To: X-SA-Exim-Connect-IP: 2a02:8011:400e:2:6f00:88c8:c921:d332 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.16.48-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Michael Ellerman commit fe06fe860250a4f01d0eaf70a2563b1997174a74 upstream. The tm-resched-dscr test has started failing sometimes, depending on what compiler it's built with, eg: test: tm_resched_dscr Check DSCR TM context switch: tm-resched-dscr: tm-resched-dscr.c:76: test_body: Assertion `rv' failed. !! child died by signal 6 When it fails we see that the compiler doesn't initialise rv to 1 before entering the inline asm block. Although that's counter intuitive, it is allowed because we tell the compiler that the inline asm will write to rv (using "=r"), meaning the original value is irrelevant. Marking it as a read/write parameter would presumably work, but it seems simpler to fix it by setting the initial value of rv in the inline asm. Fixes: 96d016108640 ("powerpc: Correct DSCR during TM context switch") Signed-off-by: Michael Ellerman Acked-by: Michael Neuling Signed-off-by: Ben Hutchings --- tools/testing/selftests/powerpc/tm/tm-resched-dscr.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/tools/testing/selftests/powerpc/tm/tm-resched-dscr.c +++ b/tools/testing/selftests/powerpc/tm/tm-resched-dscr.c @@ -45,12 +45,12 @@ int test_body(void) printf("Check DSCR TM context switch: "); fflush(stdout); for (;;) { - rv = 1; asm __volatile__ ( /* set a known value into the DSCR */ "ld 3, %[dscr1];" "mtspr %[sprn_dscr], 3;" + "li %[rv], 1;" /* start and suspend a transaction */ TBEGIN "beq 1f;"