linux-kernel - Re: [RFC][PATCH][REGRESSION FIX] x86/ftrace: Add ORC annotation to 64 bit ftrace assembly

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:   Sat, 23 Dec 2017 00:51:45 -0500
From:   Steven Rostedt <rostedt@...dmis.org>
To:     Josh Poimboeuf <jpoimboe@...hat.com>
Cc:     LKML <linux-kernel@...r.kernel.org>,
        Ingo Molnar <mingo@...nel.org>,
        Thomas Gleixner <tglx@...utronix.de>,
        Andrew Morton <akpm@...ux-foundation.org>, x86@...nel.org,
        Linus Torvalds <torvalds@...ux-foundation.org>
Subject: Re: [RFC][PATCH][REGRESSION FIX] x86/ftrace: Add ORC annotation to
 64 bit ftrace assembly

On Fri, 22 Dec 2017 20:43:37 -0600
Josh Poimboeuf <jpoimboe@...hat.com> wrote:

> Objtool doesn't like the fact that save_mcount_regs pushes rbp at the
> beginning, but it's never restored (directly, at least).
> 
> How about something like this instead, where it skips the original rbp
> push?  I didn't test it, but I think it should work.  It at least gets
> rid of the warnings and doesn't need any unwind hints other than the
> UNWIND_HINT_EMPTY in return_to_handler.

There's a reason I did it that way, but don't remember exactly why. I
think we discussed this a while ago when we had issues with ftrace.S
during your first iterations of objtool.

I'll have to test all different compile options and different gcc
compiler versions.

-- Steve