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=-9.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,USER_AGENT_GIT 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 18378C43381 for ; Thu, 7 Mar 2019 08:22:57 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id DE23920840 for ; Thu, 7 Mar 2019 08:22:56 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726195AbfCGIWz (ORCPT ); Thu, 7 Mar 2019 03:22:55 -0500 Received: from mga01.intel.com ([192.55.52.88]:64740 "EHLO mga01.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726101AbfCGIWz (ORCPT ); Thu, 7 Mar 2019 03:22:55 -0500 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga006.fm.intel.com ([10.253.24.20]) by fmsmga101.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 07 Mar 2019 00:22:54 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.58,451,1544515200"; d="scan'208";a="325019415" Received: from bob-dev.sh.intel.com ([10.239.15.128]) by fmsmga006.fm.intel.com with ESMTP; 07 Mar 2019 00:22:53 -0800 From: Tong Bo To: shuah@kernel.org Cc: luto@kernel.org, linux-kselftest@vger.kernel.org, linux-kernel@vger.kernel.org, Tong Bo Subject: [PATCH] selftests/x86: Support Atom for syscall_arg_fault test Date: Thu, 7 Mar 2019 16:25:40 +0800 Message-Id: <1551947140-22166-1-git-send-email-bo.tong@intel.com> X-Mailer: git-send-email 2.7.4 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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 expception 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. Accroding 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 --- tools/testing/selftests/x86/syscall_arg_fault.c | 6 ++++-- 1 file changed, 4 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..38cd246 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 +73,9 @@ int main() if (sigaltstack(&stack, NULL) != 0) err(1, "sigaltstack"); - sethandler(SIGSEGV, sigsegv, SA_ONSTACK); + sethandler(SIGSEGV, sigsegv_or_sigbus, SA_ONSTACK); + /* Atom CPUs may trigger sigbus for below SYSENTER exception case */ + sethandler(SIGBUS, sigsegv_or_sigbus, SA_ONSTACK); sethandler(SIGILL, sigill, SA_ONSTACK); /* -- 2.7.4