From nobody Tue Jul 23 21:50:23 2024 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 4WT9mv5y8Zz5R0Rx; Tue, 23 Jul 2024 21:50:23 +0000 (UTC) (envelope-from brooks@freebsd.org) Received: from smtp.freebsd.org (smtp.freebsd.org [96.47.72.83]) (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 "R10" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 4WT9mv5RNCz4W3b; Tue, 23 Jul 2024 21:50:23 +0000 (UTC) (envelope-from brooks@freebsd.org) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=freebsd.org; s=dkim; t=1721771423; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=QD1IZ7p0MQUHXqQa1+wdiISsi3SPaUI9QYfIXuNhezk=; b=H3swi+om9zCHvldM9V6oXsz5nNb6bKub5sOLAw9hAscL9NzN3y8xboF+vpOIOqEFZ1wPI0 6H5kLYvYcV90s2SuLve1gmYQS73StlISpPSwgNAkoLuZO0u5fRcMV/3IkfmYgEhlKj/QBt L0/RWWjDUMWqg2lxEXMQoDd+Dwl/AzWqvcFR5rBrSlcmIp/a3LuxXSCmIrcy5MxYwMr8oR juB6xniy8uLkyP25nf7uhAOzaFimwxJIJT57D8pC/+MqOcHdT21UfuW53ZD/cW+qRycduu dT7Xn9fPzXxQ+9SqJGwPFiH2MFbSbaK2PbBQjZwCc8ThjZbig92jlvXscBvmAg== ARC-Seal: i=1; s=dkim; d=freebsd.org; t=1721771423; a=rsa-sha256; cv=none; b=FwlU7UQjV9TNVWuKDxL+NL1Lpyjvjw8QsCA7h+VQywyblq0fgf3btd/APPnh2WO0RXIPzx SSa3gzbr2VZ25hIiVtA5xUOqJ98kFP8kqlna9WxY4RpxnhgmC0JyNBXxLeaJsc+f5gNs7R TScJjXNRelcaWCSXP58/gK313cky05AIZ74Cmzz8hu3ib4PUwz4OSG8G+SRQLxmjx1mmYQ FgiNFJjUBZJXoTmah+a6VMYsLsoj26WeJAesEXeYLOyxxErrRJwP0a4H41dKOF72GyF/Ug IQ2TlzEck76FU+g9NEsOm5pJEew9b2c5+2UEaExKQWVGC77SVlNIdxOoXNxrsw== ARC-Authentication-Results: i=1; mx1.freebsd.org; none ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=freebsd.org; s=dkim; t=1721771423; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=QD1IZ7p0MQUHXqQa1+wdiISsi3SPaUI9QYfIXuNhezk=; b=f3W80GLi4LI8SH96EFgYgdriuCf4pJhTLyBh7jA8mlvCaxfIY/3Wnbmr1obAU/vJb6GWSR lTt9sRAIXa5kznIRgOAzNCEtnWEfdofqaE3bihpysP1X7GT67nBN4bAcdZkhHVraDJI37+ EEXl0fuiM2AyNh7MxpBr+FFf1fGWkXAx036sA+g/Ebph/bCWeHCDaDritIcSMGKjWKI3ZB 81JDjt+hNDRUj+dpVPRDIrVRIexgjoHhgfLzlMcLmd+kDNm4RTAz9ZQmptCWwNKOBtrGyo xM3PumVCX4hCuAg2HQvwOSOMHv8LOOWAmU+dFmmUDJjd4Y1PMr0qrEnnxEBHdQ== Received: from spindle.one-eyed-alien.net (spindle.one-eyed-alien.net [199.48.129.229]) (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 did not present a certificate) (Authenticated sender: brooks/mail) by smtp.freebsd.org (Postfix) with ESMTPSA id 4WT9mv4pPqzHjV; Tue, 23 Jul 2024 21:50:23 +0000 (UTC) (envelope-from brooks@freebsd.org) Received: by spindle.one-eyed-alien.net (Postfix, from userid 3001) id 6AFE13C019B; Tue, 23 Jul 2024 21:50:23 +0000 (UTC) Date: Tue, 23 Jul 2024 21:50:23 +0000 From: Brooks Davis To: src-committers@freebsd.org, dev-commits-src-all@freebsd.org, dev-commits-src-main@freebsd.org Subject: Re: git: cade8f6c118f - main - ELF auxargs: reserve a slot for CheriABI use Message-ID: References: <202407232144.46NLi2c5072120@gitrepo.freebsd.org> 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: X-BeenThere: dev-commits-src-all@freebsd.org Sender: owner-dev-commits-src-all@FreeBSD.org MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <202407232144.46NLi2c5072120@gitrepo.freebsd.org> On Tue, Jul 23, 2024 at 09:44:02PM +0000, Brooks Davis wrote: > The branch main has been updated by brooks: > > URL: https://cgit.FreeBSD.org/src/commit/?id=cade8f6c118f304eb7c91a1d423b4a97ee466284 > > commit cade8f6c118f304eb7c91a1d423b4a97ee466284 > Author: Brooks Davis > AuthorDate: 2024-07-23 21:31:44 +0000 > Commit: Brooks Davis > CommitDate: 2024-07-23 21:31:44 +0000 > > ELF auxargs: reserve a slot for CheriABI use > > Reserve slot 37 to avoid flag days downstream. > > We currently use this slot in CheriBSD to maintain counters in userspace > while providing access to them vis sysctl. CHERI support isn't landing > in FreeBSD quite yet (probably for 16 unless hardware access accelerates > radically), but it seems highly likely at this point so reserving slots > will limit future diffs in both directions. In anticipation of merging CHERI support over the next few years, we're going to start reserving values like this where we're confident in the functionality they represent and that the values will hold (either because they are under our control or because some upstream standards body like RISC-V International has allocated them.) I've started here because andrew@ noticed that Linux now has AT_HWCAP{3,4} defines and it would be disruptive for us downstream if there was a collision. -- Brooks