Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S966089Ab3HHSVA (ORCPT ); Thu, 8 Aug 2013 14:21:00 -0400 Received: from mx1.redhat.com ([209.132.183.28]:51383 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S966003Ab3HHSU6 (ORCPT ); Thu, 8 Aug 2013 14:20:58 -0400 Date: Thu, 8 Aug 2013 20:15:21 +0200 From: Oleg Nesterov To: Frederic Weisbecker Cc: Linus Torvalds , Grazvydas Ignotas , Felipe Contreras , Linux Kernel Mailing List , Ingo Molnar , Denys Vlasenko Subject: Re: [PATCH 0/1] (Was: Linux 3.11-rc4) Message-ID: <20130808181521.GA11138@redhat.com> References: <20130806154314.GA398@redhat.com> <20130807192734.GA8395@redhat.com> <20130808154107.GA28971@redhat.com> <20130808165427.GC32049@somewhere> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20130808165427.GC32049@somewhere> User-Agent: Mutt/1.5.18 (2008-05-17) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2212 Lines: 74 On 08/08, Frederic Weisbecker wrote: > > I'm all for fixing this. May be we can start by backporting a patch that > ignores the value of gen_len for instruction breakpoints in x86? Or perhaps we can start with the something like below. But probably we should move "attr.bp_len == HW_BREAKPOINT_LEN_1" check from arch_build_bp_info() to its caller, arch_validate_hwbkpt_settings(). Because: > But this bp_len > should rather be used for range breakpoints on archs that support it. Yes, exactly, and we already have the patches for amd, so bp->len can be actually != 1 but currently we can't support because it is checked in arch_build_bp_info(). Oleg. --- x/arch/x86/kernel/hw_breakpoint.c +++ x/arch/x86/kernel/hw_breakpoint.c @@ -208,19 +208,16 @@ int arch_bp_generic_fields(int x86_len, { /* Type */ switch (x86_type) { - case X86_BREAKPOINT_EXECUTE: - if (x86_len != X86_BREAKPOINT_LEN_X) - return -EINVAL; - - *gen_type = HW_BREAKPOINT_X; - *gen_len = sizeof(long); - return 0; case X86_BREAKPOINT_WRITE: *gen_type = HW_BREAKPOINT_W; break; case X86_BREAKPOINT_RW: *gen_type = HW_BREAKPOINT_W | HW_BREAKPOINT_R; break; + case X86_BREAKPOINT_EXECUTE: + *gen_type = HW_BREAKPOINT_X; + if (x86_len == X86_BREAKPOINT_LEN_1) + break; default: return -EINVAL; } @@ -265,15 +262,11 @@ static int arch_build_bp_info(struct per break; case HW_BREAKPOINT_X: info->type = X86_BREAKPOINT_EXECUTE; - /* - * x86 inst breakpoints need to have a specific undefined len. - * But we still need to check userspace is not trying to setup - * an unsupported length, to get a range breakpoint for example. - */ - if (bp->attr.bp_len == sizeof(long)) { - info->len = X86_BREAKPOINT_LEN_X; - return 0; - } + /* until we change tools/perf */ + if (bp->attr.bp_len == sizeof(long)) + bp->attr.bp_len = HW_BREAKPOINT_LEN_1; + if (bp->attr.bp_len == HW_BREAKPOINT_LEN_1) + break; default: return -EINVAL; } -- 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/