From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-1.0 required=3.0 tests=MAILING_LIST_MULTI,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 26ACEC43387 for ; Thu, 20 Dec 2018 12:54:21 +0000 (UTC) Received: from lists.ozlabs.org (lists.ozlabs.org [203.11.71.2]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 96B6D2084A for ; Thu, 20 Dec 2018 12:54:20 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 96B6D2084A Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=ellerman.id.au Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Received: from lists.ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3]) by lists.ozlabs.org (Postfix) with ESMTP id 43LBXp4HtGzDqxZ for ; Thu, 20 Dec 2018 23:54:18 +1100 (AEDT) Authentication-Results: lists.ozlabs.org; dmarc=none (p=none dis=none) header.from=ellerman.id.au Received: from ozlabs.org (bilbo.ozlabs.org [203.11.71.1]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 43LBV6538yzDqSc for ; Thu, 20 Dec 2018 23:51:58 +1100 (AEDT) Authentication-Results: lists.ozlabs.org; dmarc=none (p=none dis=none) header.from=ellerman.id.au Received: from authenticated.ozlabs.org (localhost [127.0.0.1]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPSA id 43LBV61B8Lz9s8r; Thu, 20 Dec 2018 23:51:58 +1100 (AEDT) Authentication-Results: ozlabs.org; dmarc=none (p=none dis=none) header.from=ellerman.id.au From: Michael Ellerman To: Breno Leitao , linuxppc-dev@lists.ozlabs.org Subject: Re: [PATCH] selftests/powerpc: New TM signal self test In-Reply-To: <1543411413-23863-1-git-send-email-leitao@debian.org> References: <1542828069-29100-1-git-send-email-leitao@debian.org> <1543411413-23863-1-git-send-email-leitao@debian.org> Date: Thu, 20 Dec 2018 23:51:56 +1100 Message-ID: <875zvoqs2b.fsf@concordia.ellerman.id.au> MIME-Version: 1.0 Content-Type: text/plain X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Breno Leitao , mikey@neuling.org, gromero@linux.vnet.ibm.com Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" Breno Leitao writes: > A new self test that forces MSR[TS] to be set without calling any TM > instruction. This test also tries to cause a page fault at a signal > handler, exactly between MSR[TS] set and tm_recheckpoint(), forcing > thread->texasr to be rewritten with TEXASR[FS] = 0, which will cause a BUG > when tm_recheckpoint() is called. > > This test is not deterministic since it is hard to guarantee that the page > access will cause a page fault. Tests have shown that the bug could be > exposed with few interactions in a buggy kernel. This test is configured to > loop 5000x, having a good chance to hit the kernel issue in just one run. > This self test takes less than two seconds to run. > > This test uses set/getcontext because the kernel will recheckpoint > zeroed structures, causing the test to segfault, which is undesired because > the test needs to rerun, so, there is a signal handler for SIGSEGV which > will restart the test. Hi Breno, Thanks for the test, some of these TM tests are getting pretty advanced! :) Unfortunately it doesn't build in a few configurations. On Ubuntu 18.10 built with powerpc-linux-gnu-gcc I get: tm-signal-force-msr.c: In function 'trap_signal_handler': tm-signal-force-msr.c:42:19: error: 'union uc_regs_ptr' has no member named 'gp_regs'; did you mean 'uc_regs'? ucp->uc_mcontext.gp_regs[PT_MSR] |= MSR_TS_S; ^~~~~~~ uc_regs tm-signal-force-msr.c:17:29: error: left shift count >= width of type [-Werror=shift-count-overflow] #define __MASK(X) (1UL<<(X)) ^~ tm-signal-force-msr.c:20:25: note: in expansion of macro '__MASK' #define MSR_TS_S __MASK(MSR_TS_S_LG) /* Transaction Suspended */ ^~~~~~ tm-signal-force-msr.c:42:38: note: in expansion of macro 'MSR_TS_S' ucp->uc_mcontext.gp_regs[PT_MSR] |= MSR_TS_S; ^~~~~~~~ And using powerpc64le-linux-gnu-gcc I get: In file included from /usr/powerpc64le-linux-gnu/include/string.h:494, from tm-signal-force-msr.c:10: In function 'memcpy', inlined from 'trap_signal_handler' at tm-signal-force-msr.c:39:2: /usr/powerpc64le-linux-gnu/include/bits/string_fortified.h:34:10: error: '__builtin_memcpy' accessing 1272 bytes at offsets 8 and 168 overlaps 1112 bytes at offset 168 [-Werror=restrict] return __builtin___memcpy_chk (__dest, __src, __len, __bos0 (__dest)); ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ cheers