From nobody Mon Jan 10 22:50:40 2022 X-Original-To: dev-commits-src-all@mlmmj.nyi.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mlmmj.nyi.freebsd.org (Postfix) with ESMTP id C857219427AD; Mon, 10 Jan 2022 22:50:42 +0000 (UTC) (envelope-from jhb@FreeBSD.org) Received: from smtp.freebsd.org (smtp.freebsd.org [IPv6:2610:1c1:1:606c::24b:4]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256 client-signature RSA-PSS (4096 bits) client-digest SHA256) (Client CN "smtp.freebsd.org", Issuer "R3" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 4JXpvQ3pMFz4nNG; Mon, 10 Jan 2022 22:50:42 +0000 (UTC) (envelope-from jhb@FreeBSD.org) Received: from [10.0.1.4] (ralph.baldwin.cx [66.234.199.215]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (Client did not present a certificate) (Authenticated sender: jhb) by smtp.freebsd.org (Postfix) with ESMTPSA id B4F052D765; Mon, 10 Jan 2022 22:50:41 +0000 (UTC) (envelope-from jhb@FreeBSD.org) Message-ID: <61fa2498-3516-0f1b-fb24-270d38f0472f@FreeBSD.org> Date: Mon, 10 Jan 2022 14:50:40 -0800 List-Id: Commit messages for all branches of the src repository List-Archive: https://lists.freebsd.org/archives/dev-commits-src-all List-Help: List-Post: List-Subscribe: List-Unsubscribe: Sender: owner-dev-commits-src-all@freebsd.org X-BeenThere: dev-commits-src-all@freebsd.org MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.14; rv:91.0) Gecko/20100101 Thunderbird/91.4.1 Content-Language: en-US To: Olivier Houchard , Warner Losh Cc: Warner Losh , src-committers , dev-commits-src-all@freebsd.org, dev-commits-src-main@freebsd.org References: <202201071627.207GRsGX062055@gitrepo.freebsd.org> <45275428-75e2-aaae-bed3-e5e84b39e17c@FreeBSD.org> From: John Baldwin Subject: Re: git: d6c0538dae8d - main - ddb: Remove SOFTWARE_SSTEP support In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=freebsd.org; s=dkim; t=1641855042; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=GreXHWFi+W8xaf/Lk4K+JVceT3JOJl7Y4QpF+WHIU08=; b=r8XWk2kHKy5EwwlsjEOrQGDHHbx437mv1IMI68pnCPXyOKE5EE09g6tlAb6sKl6lg8tlGV j3D/KI5oHVpq3dWlmOjjA1XVGVorlVSSbBdm9KSJIfAkhVCrV2NuYlRrIgUBJvT1Qih7HX i5NHxdhEC0EGaCLpwKkq1Mc9V+MxKUBeUfAj8YJFfAY2e9YFXrqec0Iou2LXvOvtSM9adP H0OMd/wF/U/nObRiROKNLolHG3zWRhmSKPIRdaWrNzZAGQxZk9mMMgFShXwjsImvb8L5Fv XIBGqDyMjm7NSSJFeQtPdkp72g2kFZDMF6np0qe2PrhMX2blvrJU6YTliTqlmA== ARC-Seal: i=1; s=dkim; d=freebsd.org; t=1641855042; a=rsa-sha256; cv=none; b=aNkj0PwNe2RHADI1J8kUrGpcVqe370xewyhr8VjogR88rytaeTWQXI2aEihaCVTSfI6NCu d5ZXCtgOkPUFwCtYvVh96t9THpOmGMN+74Yi01CfB7sh7LJJ7CZj9AXgCeC7DJ2okI4yQz oRQMULEj7BXSgAPro8belhecghNmW5L0aw63yLcjuMT3xxsg5j8vvgHRAK/K58LMxTdTYB VNCRzaR20u102yGJNK4pHLVjEv6MlwjXYR1Z2dQuQZHZ+UGVCYrmRGcmJ1sQO6NTbdm6Im Cg6gMHFtTcro6nJu6M6hHIN+NjUuyxzlGqsWX6WtqC/X4SpMUDQrakqjDjvJsA== ARC-Authentication-Results: i=1; mx1.freebsd.org; none X-ThisMailContainsUnwantedMimeParts: N On 1/10/22 1:37 PM, Olivier Houchard wrote: > On Mon, Jan 10, 2022 at 02:14:54PM -0700, Warner Losh wrote: >> On Mon, Jan 10, 2022 at 12:48 PM John Baldwin wrote: >> >>> On 1/7/22 8:27 AM, Warner Losh wrote: >>>> The branch main has been updated by imp: >>>> >>>> URL: >>> https://cgit.FreeBSD.org/src/commit/?id=d6c0538dae8d138219dfd051994a44c50e741212 >>>> >>>> commit d6c0538dae8d138219dfd051994a44c50e741212 >>>> Author: Warner Losh >>>> AuthorDate: 2022-01-07 16:25:33 +0000 >>>> Commit: Warner Losh >>>> CommitDate: 2022-01-07 16:25:33 +0000 >>>> >>>> ddb: Remove SOFTWARE_SSTEP support >>>> >>>> It was needed for mips only, and only kinda sorta worked for mips. >>> It >>>> can be brought back if we grow another architecture that need it. >>>> >>>> Sponsored by: Netflix >>> >>> RISC-V would need it in theory (no hardware single step), but no one has >>> felt the >>> need to implement the backend support for it. I think 32-bit arm doesn't >>> support >>> hardware single step either (but again, no one has bothered to add the >>> backend >>> support). >>> >> >> Generally, I agree with these thoughts. I went ahead with the removal >> because I >> knew it would be easy to bring back, even years from now should someone[tm] >> have an implementation for those platforms (though I thought 32-bit arm did >> have >> single step in hardware). >> >> Should I put it back? Or should we wait until someone shows up with support >> for >> a supported platform? >> > > It was used for arm, but only older arm, ie v4/v5, pretty sure newer > cores do have hardware breakpoints. They have hardware breakpoints/watchpoints, not sure if they have single step. In GDB 32-bit arm only supports software single step, even on Linux. -- John Baldwin