From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 7523 invoked by alias); 25 May 2018 18:41:34 -0000 Mailing-List: contact gdb-patches-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: gdb-patches-owner@sourceware.org Received: (qmail 7503 invoked by uid 89); 25 May 2018 18:41:33 -0000 Authentication-Results: sourceware.org; auth=none X-Virus-Found: No X-Spam-SWARE-Status: No, score=-25.6 required=5.0 tests=AWL,BAYES_00,GIT_PATCH_0,GIT_PATCH_1,GIT_PATCH_2,GIT_PATCH_3,SPF_HELO_PASS autolearn=ham version=3.3.2 spammy=Hx-languages-length:2855 X-HELO: mx1.redhat.com Received: from mx3-rdu2.redhat.com (HELO mx1.redhat.com) (66.187.233.73) by sourceware.org (qpsmtpd/0.93/v0.84-503-g423c35a) with ESMTP; Fri, 25 May 2018 18:41:31 +0000 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.rdu2.redhat.com [10.11.54.6]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 467EEBB42F; Fri, 25 May 2018 18:41:30 +0000 (UTC) Received: from localhost (unused-10-15-17-196.yyz.redhat.com [10.15.17.196]) by smtp.corp.redhat.com (Postfix) with ESMTP id 29C172157F42; Fri, 25 May 2018 18:41:30 +0000 (UTC) From: Sergio Durigan Junior To: Omair Javaid Cc: gdb-patches@sourceware.org Subject: Re: [PATCH] [PR gdb/23210] Unset gdbarch significant_addr_bit by default References: <1527023088-10837-1-git-send-email-omair.javaid@linaro.org> Date: Fri, 25 May 2018 18:44:00 -0000 In-Reply-To: <1527023088-10837-1-git-send-email-omair.javaid@linaro.org> (Omair Javaid's message of "Wed, 23 May 2018 02:04:48 +0500") Message-ID: <87zi0n1sti.fsf@redhat.com> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/25.3 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain X-IsSubscribed: yes X-SW-Source: 2018-05/txt/msg00696.txt.bz2 On Tuesday, May 22 2018, Omair Javaid wrote: > This patch fixes a bug introduced by fix to AArch64 pointer tagging. > > In our fix for tagged pointer support our agreed approach was to sign > extend user-space address after clearing tag bits. This is not same > for all architectures and this patch allows sign extension for > addresses on targets which specifically set significant_addr_bit. > > More information about patch that caused the issues and discussion > around tagged pointer support can be found in links below: > > https://sourceware.org/ml/gdb-patches/2018-05/msg00000.html > https://sourceware.org/ml/gdb-patches/2017-12/msg00159.html FWIW, I've tested your patch locally and it fixes the timeout issues I've been seeing when debugging 32-bit binaries with a 64-bit GDB. Thanks. > gdb/ChangeLog: > > 2018-05-23 Omair Javaid > > * gdbarch.c (verify_gdbarch): Update. > * utils.c (address_significant): Update. > --- > gdb/gdbarch.c | 3 +-- > gdb/utils.c | 5 +++-- > 2 files changed, 4 insertions(+), 4 deletions(-) > > diff --git a/gdb/gdbarch.c b/gdb/gdbarch.c > index c430ebe..5593911 100644 > --- a/gdb/gdbarch.c > +++ b/gdb/gdbarch.c > @@ -615,8 +615,7 @@ verify_gdbarch (struct gdbarch *gdbarch) > /* Skip verify of stabs_argument_has_addr, invalid_p == 0 */ > /* Skip verify of convert_from_func_ptr_addr, invalid_p == 0 */ > /* Skip verify of addr_bits_remove, invalid_p == 0 */ > - if (gdbarch->significant_addr_bit == 0) > - gdbarch->significant_addr_bit = gdbarch_addr_bit (gdbarch); > + /* Skip verify of significant_addr_bit, invalid_p == 0 */ > /* Skip verify of software_single_step, has predicate. */ > /* Skip verify of single_step_through_delay, has predicate. */ > /* Skip verify of print_insn, invalid_p == 0 */ > diff --git a/gdb/utils.c b/gdb/utils.c > index 9c5bf68..91c0f2b 100644 > --- a/gdb/utils.c > +++ b/gdb/utils.c > @@ -2708,10 +2708,11 @@ address_significant (gdbarch *gdbarch, CORE_ADDR addr) > /* Clear insignificant bits of a target address and sign extend resulting > address, avoiding shifts larger or equal than the width of a CORE_ADDR. > The local variable ADDR_BIT stops the compiler reporting a shift overflow > - when it won't occur. */ > + when it won't occur. Skip updating of target address if current target has > + not set gdbarch significant_addr_bit. */ > int addr_bit = gdbarch_significant_addr_bit (gdbarch); > > - if (addr_bit < (sizeof (CORE_ADDR) * HOST_CHAR_BIT)) > + if (addr_bit && (addr_bit < (sizeof (CORE_ADDR) * HOST_CHAR_BIT))) > { > CORE_ADDR sign = (CORE_ADDR) 1 << (addr_bit - 1); > addr &= ((CORE_ADDR) 1 << addr_bit) - 1; > -- > 2.7.4 -- Sergio GPG key ID: 237A 54B1 0287 28BF 00EF 31F4 D0EB 7628 65FC 5E36 Please send encrypted e-mail if possible http://sergiodj.net/