From owner-freebsd-arch@freebsd.org Tue Sep 12 15:43:06 2017 Return-Path: Delivered-To: freebsd-arch@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id 6432BE0F487 for ; Tue, 12 Sep 2017 15:43:06 +0000 (UTC) (envelope-from wlosh@bsdimp.com) Received: from mailman.ysv.freebsd.org (unknown [127.0.1.3]) by mx1.freebsd.org (Postfix) with ESMTP id 3E6D976D07 for ; Tue, 12 Sep 2017 15:43:06 +0000 (UTC) (envelope-from wlosh@bsdimp.com) Received: by mailman.ysv.freebsd.org (Postfix) id 3D863E0F486; Tue, 12 Sep 2017 15:43:06 +0000 (UTC) Delivered-To: arch@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id 3CE28E0F485 for ; Tue, 12 Sep 2017 15:43:06 +0000 (UTC) (envelope-from wlosh@bsdimp.com) Received: from mail-io0-x22a.google.com (mail-io0-x22a.google.com [IPv6:2607:f8b0:4001:c06::22a]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (Client CN "smtp.gmail.com", Issuer "Google Internet Authority G2" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id F33B076D05 for ; Tue, 12 Sep 2017 15:43:05 +0000 (UTC) (envelope-from wlosh@bsdimp.com) Received: by mail-io0-x22a.google.com with SMTP id d16so49638407ioj.3 for ; Tue, 12 Sep 2017 08:43:05 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bsdimp-com.20150623.gappssmtp.com; s=20150623; h=mime-version:sender:in-reply-to:references:from:date:message-id :subject:to:cc; bh=hWOIIeuPNIMIMfsXwmJcr6Mgsl7rft22ZvV4EF1f/FM=; b=i0I8T9V82zHB8GnGglIBInecrd5odCVDLDlpKvDnGHAQ6aO8qq27DE9rXAP+fOdEZ8 3u7tVWj0hiYurimq1tkrpLq0uNaH6HmDRCfb1NkAemSs4C3UjdHWPoOMKK8tdIVbap0+ PtoWqFWDLzx9RRnEuGeURYGgXVHsQJUpDR2D7a+glYqKnskJXU6mEc6T79VUnF/gDRWm qbfJcPrVVYiMnYzbyBgZPnnR6omj2Vn+6M1X9TOGC2h0iHDAnfTapU/m7sU0acQndXFe dG0XHkJvmO+uQvtnQ0ibYerQyWcLYzSzjquOS69OsHtKzJFCij7utx6UcFIWZ4TnGhxX R6fg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:sender:in-reply-to:references:from :date:message-id:subject:to:cc; bh=hWOIIeuPNIMIMfsXwmJcr6Mgsl7rft22ZvV4EF1f/FM=; b=Qb772FLcWV5mvV99/hfNHy1uSYVv8hVzOmr7Kl6tiQCVH9AoSXSrGAdHGnuVQweDf5 5aMhKAZ/EX08hlVwcKYXFKFXWztn1laVqz801kEk/hHRnTNwhMCPMdB5vKbzMI1R3xrY p/dt+Z2NBrBOV0Qb/PJM5dcOAU2Q8MVFSMxG9kocn1HD/PJXNvq/R65bqPebozt/Tt8T wr6RSALyy3m3lCXinxgiUVNKcFAcQ8OYKTAacX8jM3XjFhuV7c0kQOQwrXBbKhoqcczt sXDXpePIxfHZuSMs1nusdaJwMKkc6kGcpKwsrK7YnX2u2bnb3GOvZbmGtzI6BgM17pz0 m1Zw== X-Gm-Message-State: AHPjjUiWeyDeEQObdJJkNBHkNOafKTrR2SOgtNXW3QC+EqHes83wNNCh p5Zjc06dnRUoU6dVJpEK4c4qlc/xpu0a X-Google-Smtp-Source: ADKCNb4Blk5pWyG9T9kcEH8fUMtYEZeixCTlS5QesXKFwU6HCchdak2mWSh0SHx+FN292CmGBuBs3PqkMhHduDHN9p8= X-Received: by 10.107.133.92 with SMTP id h89mr13560679iod.208.1505230985114; Tue, 12 Sep 2017 08:43:05 -0700 (PDT) MIME-Version: 1.0 Sender: wlosh@bsdimp.com Received: by 10.79.10.71 with HTTP; Tue, 12 Sep 2017 08:43:04 -0700 (PDT) X-Originating-IP: [2603:300b:6:5100:809b:5e24:6d84:c8fa] In-Reply-To: <5184520.CTdkFHEYDQ@ralph.baldwin.cx> References: <26458208-EC4B-4647-8271-DF480EDD57DF@xcllnt.net> <5184520.CTdkFHEYDQ@ralph.baldwin.cx> From: Warner Losh Date: Tue, 12 Sep 2017 09:43:04 -0600 X-Google-Sender-Auth: HjIXfWCVfs36aHckbUai-USgD_M Message-ID: Subject: Re: ELF auxiliary vector tags To: John Baldwin Cc: Marcel Moolenaar , "freebsd-arch@freebsd.org" Content-Type: text/plain; charset="UTF-8" X-Content-Filtered-By: Mailman/MimeDel 2.1.23 X-BeenThere: freebsd-arch@freebsd.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: Discussion related to FreeBSD architecture List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 12 Sep 2017 15:43:06 -0000 On Mon, Sep 11, 2017 at 4:45 PM, John Baldwin wrote: > On Monday, September 11, 2017 12:05:02 PM Marcel Moolenaar wrote: > > > > > On Sep 8, 2017, at 10:36 AM, John Baldwin wrote: > > > > > > > I know Justin changed time_t to 64-bit on 32-bit powerpc which > effectively broke 32-bit powerpc earlier, but this change would break both > 32-bit and 64-bit powerpc and is probably more disruptive (in theory some > binaries might have worked with a wrong time_t, but renumber AT_STACKPROT, > etc. will probably break every binary). > > > > That probably depends on the byte order. I would think widening > > time_t on a big-endian machine is a lot more disruptive than > > doing it on a little-endian machine. > > > > That said and along the lines of what @imp said: > > Maybe add a a MD macro (e.g. NO_MI_AUX_VECTORS) whose existence > > suppresses the MI definitions of AT_* so that MD headers can > > define their own? > > Going forward I would like to standardize on common values for new vectors > added. The current implementation of 'info auxv' for GDB assumes they > are the same on all architectures (and judging by the binutils / gdb bits > for Linux, Linux uses the same AT_* values on all platforms). Are you > running powerpc binaries yourself? The only person who I know is who has > replied (Justin) is fine with just pulling the tier-2 card on powerpc to > bring it inline with all the other platforms (which are already identical). > I think aligning is the right thing, regardless of tier status. The question about 'adding compat' is a separate issue, imho. > One suggestion was to set a value in AT_FLAGS (currently always set to > zero) > that binaries could then use to detect the new layout on ppc. > This is a path forward if we want to maintain upgradability across this incident. I don't think it's incumbent on John to do it (unless he wants to). It's incumbent on the powerpc folks if they need the compatibility. If this were arm the calculous would be different (since lots of people do binary upgrades and it's de-facto nearly tier 1) or even mips (where some people do binary upgrades, despite being definitely not tier 1). OTOH, if John did this to arm and didn't do compat shims, myself or some other arm user would do them. The only question would be how much snark would make its way into the commit message :) It's also a reasonable fallback plan should more users than just Justin be affected given the bumpy nature of -current at time. Warner