Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933207AbbDJNHb (ORCPT ); Fri, 10 Apr 2015 09:07:31 -0400 Received: from mx1.redhat.com ([209.132.183.28]:44605 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933163AbbDJNH0 (ORCPT ); Fri, 10 Apr 2015 09:07:26 -0400 From: Denys Vlasenko To: linux-kernel@vger.kernel.org Cc: Denys Vlasenko , Jiri Olsa , Peter Zijlstra , Paul Mackerras , Ingo Molnar , Arnaldo Carvalho de Melo , x86@kernel.org Subject: [PATCH 3/4] perf/x86_64: get_regs_user: Simplify regs_user->abi setting code Date: Fri, 10 Apr 2015 15:06:58 +0200 Message-Id: <1428671219-29341-3-git-send-email-dvlasenk@redhat.com> In-Reply-To: <1428671219-29341-1-git-send-email-dvlasenk@redhat.com> References: <1428671219-29341-1-git-send-email-dvlasenk@redhat.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2057 Lines: 56 user_64bit_mode(regs) basically checks regs->cs to point to a 64-bit segment. This check used to be unreliable here because regs->cs was not always correct in syscalls. Now regs->cs is always correct: in syscalls, in interrupts, in exceptions. No need to emply heuristics here. Signed-off-by: Denys Vlasenko CC: Jiri Olsa CC: Peter Zijlstra CC: Paul Mackerras CC: Ingo Molnar CC: Arnaldo Carvalho de Melo CC: x86@kernel.org CC: linux-kernel@vger.kernel.org --- arch/x86/kernel/perf_regs.c | 18 ++---------------- 1 file changed, 2 insertions(+), 16 deletions(-) diff --git a/arch/x86/kernel/perf_regs.c b/arch/x86/kernel/perf_regs.c index a8d4e48..8157d39 100644 --- a/arch/x86/kernel/perf_regs.c +++ b/arch/x86/kernel/perf_regs.c @@ -166,22 +166,8 @@ void perf_get_regs_user(struct perf_regs *regs_user, * be careful not to look at any other percpu variables that might * change during context switches. */ - if (IS_ENABLED(CONFIG_IA32_EMULATION) && - task_thread_info(current)->status & TS_COMPAT) { - /* Easy case: we're in a compat syscall. */ - regs_user->abi = PERF_SAMPLE_REGS_ABI_32; - } else if (user_regs->orig_ax != -1) { - /* - * We're probably in a 64-bit syscall. - * Warning: this code is severely racy. At least it's better - * than just blindly copying user_regs. - */ - regs_user->abi = PERF_SAMPLE_REGS_ABI_64; - } else { - /* We're probably in an interrupt or exception. */ - regs_user->abi = user_64bit_mode(user_regs) ? - PERF_SAMPLE_REGS_ABI_64 : PERF_SAMPLE_REGS_ABI_32; - } + regs_user->abi = user_64bit_mode(user_regs) ? + PERF_SAMPLE_REGS_ABI_64 : PERF_SAMPLE_REGS_ABI_32; regs_user->regs = regs_user_copy; } -- 1.8.1.4 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/