Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753342AbcJLLQj (ORCPT ); Wed, 12 Oct 2016 07:16:39 -0400 Received: from mail-oi0-f68.google.com ([209.85.218.68]:33905 "EHLO mail-oi0-f68.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752060AbcJLLQa (ORCPT ); Wed, 12 Oct 2016 07:16:30 -0400 MIME-Version: 1.0 In-Reply-To: References: From: Yao Qi Date: Wed, 12 Oct 2016 12:16:29 +0100 Message-ID: Subject: Re: [PATCH 3/4] arm64: Allow hw watchpoint of length 3,5,6 and 7 To: Pratyush Anand Cc: will.deacon@arm.com, Mark Rutland , labath@google.com, onestero@redhat.com, linux-kernel@vger.kernel.org, Jan Kratochvil , linux-arm-kernel@lists.infradead.org Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: 8bit X-MIME-Autoconverted: from quoted-printable to 8bit by mail.home.local id u9CBGg0D011936 Content-Length: 617 Lines: 15 On Wed, Oct 12, 2016 at 6:58 AM, Pratyush Anand wrote: > Since, arm64 can support all offset within a double word limit. Therefore, > now support other lengths within that range as well. How does ptracer (like GDB) detect kernel has already supported all byte address select values? I suppose ptrace(NT_ARM_HW_WATCH, ) with len is 3 or 5 fail on current kernel but is of success after your patches applied. GDB is aware of the byte address select limitation in kernel, so it always sets 1,2,4,8 in len in ctrl. GDB needs to know whether the limitation is still there or not. -- Yao (齐尧)