From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <linux-kernel-owner@vger.kernel.org>
Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand
        id S1755538AbdETX3l (ORCPT <rfc822;w@1wt.eu>);
        Sat, 20 May 2017 19:29:41 -0400
Received: from mail-it0-f66.google.com ([209.85.214.66]:36500 "EHLO
        mail-it0-f66.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org
        with ESMTP id S1751367AbdETX3j (ORCPT
        <rfc822;linux-kernel@vger.kernel.org>);
        Sat, 20 May 2017 19:29:39 -0400
MIME-Version: 1.0
In-Reply-To: <CA+55aFy_uKkr1RAQGD6sptymmGZzN8-E=rEMLP-89k8oz5_07w@mail.gmail.com>
References: <20170505122200.31436-1-jslaby@suse.cz> <20170505122200.31436-7-jslaby@suse.cz>
 <CA+55aFzEF_A1MzH8P8EX35FSci7UFj_+5LdsEFVai1DYtCk-Hg@mail.gmail.com>
 <20170507165524.cdxfuwbd5alr7v6k@treble> <20170519205354.caeyqri2k6gvso3w@treble>
 <8dbbb971-fc41-fba2-f356-931a7eabe6ef@zytor.com> <20170519212913.otir6mlujoxoy3ha@treble>
 <20170519213556.pv5kxocfprfkloay@treble> <CALCETrWxwhKvm2jYG+d2xupd6uuEDAeBkafPonYNhxF6O=+qVA@mail.gmail.com>
 <CA+55aFyB6nb7VZthWOdN9YgS0UHsWxzaersjfQw1s4uCH_Dv-g@mail.gmail.com>
 <CALCETrVjpxYYBwFxWq+oQ9XCmnKsnw=xV0p7dxx-DJGvGCCPgA@mail.gmail.com> <CA+55aFy_uKkr1RAQGD6sptymmGZzN8-E=rEMLP-89k8oz5_07w@mail.gmail.com>
From: Linus Torvalds <torvalds@linux-foundation.org>
Date: Sat, 20 May 2017 16:29:37 -0700
X-Google-Sender-Auth: Mjue0no33gLn1iYstspngDvYdss
Message-ID: <CA+55aFzNDM6AN5728GPrmCtvRGYyqC7SZH0aQbSm=bdftYVLEg@mail.gmail.com>
Subject: Re: [PATCH 7/7] DWARF: add the config option
To: Andy Lutomirski <luto@kernel.org>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>, "H. J. Lu" <hjl.tools@gmail.com>,
        "H. Peter Anvin" <hpa@zytor.com>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        Jiri Slaby <jslaby@suse.cz>, Andrew Morton <akpm@linux-foundation.org>,
        live-patching@vger.kernel.org, Thomas Gleixner <tglx@linutronix.de>,
        Ingo Molnar <mingo@redhat.com>,
        "the arch/x86 maintainers" <x86@kernel.org>,
        Jiri Kosina <jikos@kernel.org>
Content-Type: text/plain; charset="UTF-8"
Sender: linux-kernel-owner@vger.kernel.org
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org

On Sat, May 20, 2017 at 4:00 PM, Linus Torvalds
<torvalds@linux-foundation.org> wrote:
>
> hjl already posted an example of the kinds of horrors glibc does to do
> things "right".

Side note: we'd hopefully/presumably never need anything _that_
disgusting for the kernel, so hjl's example is probably an extreme
one.

But even when we just did the pushq/popq_cfi macros etc to try to have
simple and reasonably legible annotations for the common cases, it got
pretty ugly.

It wasn't that extreme glibc kind of "50 lines of ugly for two
instructions of code", but it was pretty bad. And as far as I know we
never even tried to annotate places where we did "pushf/pop %reg" in
inline asm (for saving/restoring flags)

               Linus