From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from smtp.polymtl.ca (smtp.polymtl.ca [132.207.4.11]) by sourceware.org (Postfix) with ESMTPS id 3577D3858417 for ; Sun, 19 Sep 2021 02:04:32 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.1 sourceware.org 3577D3858417 Received: from simark.ca (simark.ca [158.69.221.121]) (authenticated bits=0) by smtp.polymtl.ca (8.14.7/8.14.7) with ESMTP id 18J24QMg026998 (version=TLSv1/SSLv3 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Sat, 18 Sep 2021 22:04:30 -0400 DKIM-Filter: OpenDKIM Filter v2.11.0 smtp.polymtl.ca 18J24QMg026998 Received: from [10.0.0.11] (192-222-157-6.qc.cable.ebox.net [192.222.157.6]) (using TLSv1.3 with cipher TLS_AES_128_GCM_SHA256 (128/128 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by simark.ca (Postfix) with ESMTPSA id 65E651EDF7; Sat, 18 Sep 2021 22:04:25 -0400 (EDT) Subject: Re: GDB will set bp at a function for RISC-V when step over this function call To: "Ge, Lei" , "gdb@sourceware.org" Cc: "Xin, Wenyan" References: From: Simon Marchi Message-ID: Date: Sat, 18 Sep 2021 22:04:23 -0400 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.13.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit X-Poly-FromMTA: (simark.ca [158.69.221.121]) at Sun, 19 Sep 2021 02:04:26 +0000 X-Spam-Status: No, score=-5.3 required=5.0 tests=BAYES_00, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, DKIM_VALID_EF, NICE_REPLY_A, RCVD_IN_MSPIKE_H3, RCVD_IN_MSPIKE_WL, SPF_HELO_PASS, SPF_PASS, TXREP autolearn=ham autolearn_force=no version=3.4.4 X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on server2.sourceware.org X-BeenThere: gdb@sourceware.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Gdb mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sun, 19 Sep 2021 02:04:35 -0000 On 2021-09-17 3:57 a.m., Ge, Lei wrote: > Hi all, > > I have a question about GDB for RISC-V. When step over a function call, GDB will set a bp at this function only for RISC-V. Do you think it is a bug? Thanks. Hi, Probably because RISC-V uses software single step to implement single instruction stepping. It implements the gdbarch_software_single_step hook: https://gitlab.com/gnutools/binutils-gdb/-/blob/master/gdb/riscv-tdep.c#L3923-3940 Note that this callback is only installed in riscv_fbsd_init_abi and riscv_linux_init_abi, so is only effective when debugging a Linux or FreeBSD target. So I suppose that if you were debugging a bare-metal application, GDB would use hardware single step instead, not sure if that is by design. Simon