From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on gnuweeb.org X-Spam-Level: ** X-Spam-Status: No, score=2.5 required=5.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, RCVD_IN_DNSWL_NONE,RCVD_IN_MSPIKE_H2,SORTED_RECIPS,SPF_HELO_NONE, SPF_PASS autolearn=no autolearn_force=no version=3.4.6 Authentication-Results: gnuweeb.org; dmarc=none (p=none dis=none) header.from=tinylab.org Received-SPF: Pass (mailfrom) identity=mailfrom; client-ip=43.155.67.158; helo=bg4.exmail.qq.com; envelope-from=falcon@tinylab.org; receiver= Received: from bg4.exmail.qq.com (bg4.exmail.qq.com [43.155.67.158]) by gnuweeb.org (Postfix) with ESMTPS id 2761524B1BD for ; Sat, 26 Aug 2023 22:20:43 +0700 (WIB) X-QQ-mid: bizesmtp86t1693063226ta4guxg2 Received: from linux-lab-host.localdomain ( [116.30.128.222]) by bizesmtp.qq.com (ESMTP) with id ; Sat, 26 Aug 2023 23:20:25 +0800 (CST) X-QQ-SSF: 00200000000000E0Y000000A0000000 X-QQ-FEAT: oGOjGSUjcuC5m3wZxsbknP3cgP4dvdVHpGKzXVES4LPegOSXcM753UhCzlDVp mLG/LNKRU5YXB0XGQon33cMg56DWeXktWnwyhMAU1TTHQFRYRV7SStalgnEhsJJN1a7vd/j tuPDeq/BpugjRK8S69RyTmzPc5xgpYFJ9Lzu8hEQY64uNh0CVTkoYefU7HnP8yHc5iGfARy 6EsWuSIoVS4nCDFyycEiU6zfwYmLQ2MZ1LZbQXbefE8BJ1kYK629EKQy8pUn7CC6Mi70CRi rpNfACseCU2KFuzp/Az8ZYfpEvJ3CTgPG7Ib1uDxB9fyn1u/AQaKNewSAC1HggesTjPtKpz NIVAWbth+ufEQtTMOlVwchWZAPUyzOrzRIq8Tcb5wROtiHeXkdOanM4BEYjRFY+ja8ekDam X-QQ-GoodBg: 0 X-BIZMAIL-ID: 10831681492975296225 From: Zhangjin Wu To: ammarfaizi2@gnuweeb.org Cc: falcon@tinylab.org, gwml@vger.gnuweeb.org, inori@vnlx.org, linux-kernel@vger.kernel.org, linux@weissschuh.net, moe@gnuweeb.org, w@1wt.eu Subject: Re: [PATCH v1 0/1] Fix a stack misalign bug on _start Date: Sat, 26 Aug 2023 23:20:24 +0800 Message-Id: <20230826152024.7773-1-falcon@tinylab.org> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20230826141632.1488740-1-ammarfaizi2@gnuweeb.org> References: <20230826141632.1488740-1-ammarfaizi2@gnuweeb.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-QQ-SENDSIZE: 520 Feedback-ID: bizesmtp:tinylab.org:qybglogicsvrgz:qybglogicsvrgz5a-1 List-Id: Hi, Ammar > Hi Willy, > > Just a single quick fix. > > The ABI mandates that the %esp register must be a multiple of 16 when > executing a call instruction. > > Commit 2ab446336b17 simplified the _start function, but it didn't take > care of the %esp alignment, causing SIGSEGV on SSE and AVX programs that > use aligned move instruction (e.g., movdqa, movaps, and vmovdqa). > Yeah, I have learned carefully about the old 'sub $4, %esp' instruction for the old 3 'push' instructions, but at last forgot to add a new instruction for the new single 'push' instruction to reserve the 16-byte alignment, very sorry for this bad regression. > $eax : 0x56559000 → 0x00003f90 > $ebx : 0x56559000 → 0x00003f90 > $ecx : 0x1 > $edx : 0xf7fcaaa0 → endbr32 > $esp : 0xffffcdbc → 0x00000001 > $ebp : 0x0 > $esi : 0xffffce7c → 0xffffd096 > $edi : 0x56556060 → <_start+0> xor %ebp, %ebp > $eip : 0x56556489 → movaps %xmm0, 0x30(%esp) > > pop %eax > add $0x2b85, %eax > movups -0x1fd0(%eax), %xmm0 > → movaps %xmm0, 0x30(%esp) <== trapping instruction > movups -0x1fe0(%eax), %xmm1 > movaps %xmm1, 0x20(%esp) > movups -0x1ff0(%eax), %xmm2 > movaps %xmm2, 0x10(%esp) > movups -0x2000(%eax), %xmm3 > > [#0] Id 1, Name: "test", stopped 0x56556489 in sse_pq_add (), reason: SIGSEGV > > (gdb) bt > #0 0x56556489 in sse_pq_add () > #1 0x5655608e in main () > Since we have a new 'startup' test group, do you have a short function to trigger this error? Perhaps it is time for us to add a new 'stack alignment' test case for all of the architectures. Thanks, Zhangjin > Ensure the %esp is a multiple of 16 when executing the call instruction. > > Signed-off-by: Ammar Faizi > --- > Ammar Faizi (1): > tools/nolibc: i386: Fix a stack misalign bug on _start > > tools/include/nolibc/arch-i386.h | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > > base-commit: 6269320850097903b30be8f07a5c61d9f7592393 > -- > Ammar Faizi