From: Steven Rostedt <rostedt@goodmis.org>
To: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: LKML <linux-kernel@vger.kernel.org>,
Ingo Molnar <mingo@kernel.org>,
Thomas Gleixner <tglx@linutronix.de>,
Andrew Morton <akpm@linux-foundation.org>,
x86@kernel.org, Linus Torvalds <torvalds@linux-foundation.org>
Subject: Re: [RFC][PATCH][REGRESSION FIX] x86/ftrace: Add ORC annotation to 64 bit ftrace assembly
Date: Sat, 23 Dec 2017 00:51:45 -0500 [thread overview]
Message-ID: <20171223005145.5f4d3884@gandalf.local.home> (raw)
In-Reply-To: <20171223024337.e6ad3gqldiju7ndl@treble>
On Fri, 22 Dec 2017 20:43:37 -0600
Josh Poimboeuf <jpoimboe@redhat.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
next prev parent reply other threads:[~2017-12-23 5:51 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-12-22 18:18 [RFC][PATCH][REGRESSION FIX] x86/ftrace: Add ORC annotation to 64 bit ftrace assembly Steven Rostedt
2017-12-22 18:30 ` Josh Poimboeuf
2017-12-22 18:38 ` Steven Rostedt
2017-12-23 2:43 ` Josh Poimboeuf
2017-12-23 5:51 ` Steven Rostedt [this message]
2018-01-23 4:07 ` [PATCH] x86/ftrace: Fix ORC unwinding from ftrace handlers Josh Poimboeuf
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