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=HEADER_FROM_DIFFERENT_DOMAINS, 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 209BBC43387 for ; Tue, 8 Jan 2019 10:17:56 +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 8EA342087F for ; Tue, 8 Jan 2019 10:17:55 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 8EA342087F 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 43Yp9Y3d0rzDqSq for ; Tue, 8 Jan 2019 21:17:53 +1100 (AEDT) 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)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 43Yp7q6qSVzDqPm for ; Tue, 8 Jan 2019 21:16:23 +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 TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange ECDHE (P-256) server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPSA id 43Yp7q4x3pz9sMQ; Tue, 8 Jan 2019 21:16:23 +1100 (AEDT) From: Michael Ellerman To: Breno Leitao , linuxppc-dev@lists.ozlabs.org Subject: Re: [PATCH] selftests/powerpc: New TM signal self test In-Reply-To: <20c993da-a3ca-ba2c-1195-a81efb1cc342@debian.org> References: <1542828069-29100-1-git-send-email-leitao@debian.org> <1543411413-23863-1-git-send-email-leitao@debian.org> <875zvoqs2b.fsf@concordia.ellerman.id.au> <20c993da-a3ca-ba2c-1195-a81efb1cc342@debian.org> Date: Tue, 08 Jan 2019 21:16:22 +1100 Message-ID: <878szvtpxl.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: 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: > On 12/20/18 10:51 AM, Michael Ellerman wrote: >> 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. >> And reference the ucontext->mcontext MSR using UCONTEXT_MSR() macro. >> 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; >> ^~~~~~~~ >> > > That is because I missed the -m64 compilation flag on Makefile. I understand > that this test only make sense when compiled in 64 bits. Do you agree? I think the test could work as a 32-bit binary on a 64-bit kernel, but I don't mind if you force it to build 64-bit. cheers