From patchwork Fri Apr 19 07:10:55 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Tong, Bo" X-Patchwork-Id: 10909381 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id EA890922 for ; Fri, 19 Apr 2019 18:31:13 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id E0AA728C6D for ; Fri, 19 Apr 2019 18:31:13 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id D4BD128C79; Fri, 19 Apr 2019 18:31:13 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.9 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI, RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 7AE4F28DB3 for ; Fri, 19 Apr 2019 18:31:13 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726824AbfDSSa5 (ORCPT ); Fri, 19 Apr 2019 14:30:57 -0400 Received: from mga17.intel.com ([192.55.52.151]:24408 "EHLO mga17.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726103AbfDSSa5 (ORCPT ); Fri, 19 Apr 2019 14:30:57 -0400 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga003.fm.intel.com ([10.253.24.29]) by fmsmga107.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 19 Apr 2019 00:08:26 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.60,368,1549958400"; d="scan'208";a="150647763" Received: from bob-dev.sh.intel.com ([10.239.15.128]) by FMSMGA003.fm.intel.com with ESMTP; 19 Apr 2019 00:08:25 -0700 From: Tong Bo To: luto@kernel.org, x86@kernel.org Cc: shuah@kernel.org, linux-kselftest@vger.kernel.org, linux-kernel@vger.kernel.org, Tong Bo Subject: [PATCH v3] selftests/x86: Support Atom for syscall_arg_fault test Date: Fri, 19 Apr 2019 15:10:55 +0800 Message-Id: <1555657855-31855-1-git-send-email-bo.tong@intel.com> X-Mailer: git-send-email 2.7.4 Sender: linux-kselftest-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kselftest@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP Atom-based CPUs trigger stack fault when invoke 32-bit SYSENTER instruction with invalid register values. So we also need SIGBUS handling in this case. Following is assembly when the fault exception happens. (gdb) disassemble $eip Dump of assembler code for function __kernel_vsyscall: 0xf7fd8fe0 <+0>: push %ecx 0xf7fd8fe1 <+1>: push %edx 0xf7fd8fe2 <+2>: push %ebp 0xf7fd8fe3 <+3>: mov %esp,%ebp 0xf7fd8fe5 <+5>: sysenter 0xf7fd8fe7 <+7>: int $0x80 => 0xf7fd8fe9 <+9>: pop %ebp 0xf7fd8fea <+10>: pop %edx 0xf7fd8feb <+11>: pop %ecx 0xf7fd8fec <+12>: ret End of assembler dump. According to Intel SDM, this could also be a Stack Segment Fault(#SS, 12), except a normal Page Fault(#PF, 14). Especially, in section 6.9 of Vol.3A, both stack and page faults are within the 10th(lowest priority) class, and as it said, "exceptions within each class are implementation-dependent and may vary from processor to processor". It's expected for processors like Intel Atom to trigger stack fault(SIGBUS), while we get page fault(SIGSEGV) from common Core processors. Signed-off-by: Tong Bo Acked-by: Andy Lutomirski Acked-by: Shuah Khan Acked-by: Shuah Khan --- tools/testing/selftests/x86/syscall_arg_fault.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) diff --git a/tools/testing/selftests/x86/syscall_arg_fault.c b/tools/testing/selftests/x86/syscall_arg_fault.c index 7db4fc9..d2548401 100644 --- a/tools/testing/selftests/x86/syscall_arg_fault.c +++ b/tools/testing/selftests/x86/syscall_arg_fault.c @@ -43,7 +43,7 @@ static sigjmp_buf jmpbuf; static volatile sig_atomic_t n_errs; -static void sigsegv(int sig, siginfo_t *info, void *ctx_void) +static void sigsegv_or_sigbus(int sig, siginfo_t *info, void *ctx_void) { ucontext_t *ctx = (ucontext_t*)ctx_void; @@ -73,7 +73,13 @@ int main() if (sigaltstack(&stack, NULL) != 0) err(1, "sigaltstack"); - sethandler(SIGSEGV, sigsegv, SA_ONSTACK); + sethandler(SIGSEGV, sigsegv_or_sigbus, SA_ONSTACK); + /* + * The actual exception can vary. On Atom CPUs, we get #SS + * instead of #PF when the vDSO fails to access the stack when + * ESP is too close to 2^32, and #SS causes SIGBUS. + */ + sethandler(SIGBUS, sigsegv_or_sigbus, SA_ONSTACK); sethandler(SIGILL, sigill, SA_ONSTACK); /*