linux-kernel - Re: [PATCH 03/24] x86/paravirt: Annotate indirect calls

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Message-ID: <20180125113550.GD2228@hirez.programming.kicks-ass.net>
Date:   Thu, 25 Jan 2018 12:35:50 +0100
From:   Peter Zijlstra <peterz@...radead.org>
To:     David Woodhouse <dwmw2@...radead.org>
Cc:     Juergen Gross <jgross@...e.com>,
        Thomas Gleixner <tglx@...utronix.de>,
        Josh Poimboeuf <jpoimboe@...hat.com>,
        linux-kernel@...r.kernel.org, Dave Hansen <dave.hansen@...el.com>,
        Ashok Raj <ashok.raj@...el.com>,
        Tim Chen <tim.c.chen@...ux.intel.com>,
        Andy Lutomirski <luto@...nel.org>,
        Linus Torvalds <torvalds@...ux-foundation.org>,
        Greg KH <gregkh@...uxfoundation.org>,
        Andrea Arcangeli <aarcange@...hat.com>,
        Andi Kleen <ak@...ux.intel.com>,
        Arjan Van De Ven <arjan.van.de.ven@...el.com>,
        Dan Williams <dan.j.williams@...el.com>,
        Paolo Bonzini <pbonzini@...hat.com>,
        Jun Nakajima <jun.nakajima@...el.com>,
        Asit Mallick <asit.k.mallick@...el.com>,
        Jason Baron <jbaron@...mai.com>
Subject: Re: [PATCH 03/24] x86/paravirt: Annotate indirect calls

On Thu, Jan 25, 2018 at 10:52:53AM +0000, David Woodhouse wrote:
> OK, my brain hurts a bit but I'm happy now. Thank you.

OK, I've updated the Changelog thusly. Is this satisfactory?

---
Subject: x86/paravirt: Annotate indirect calls
From: Peter Zijlstra <peterz@...radead.org>
Date: Wed Jan 17 16:58:11 CET 2018

Paravirt emits indirect calls which get flagged by objtool retpoline
checks, annotate it away because all these indirect calls will be
patched out before we start userspace.

This patching happens through alternative_instructions() ->
apply_paravirt() -> pv_init_ops.patch() which will eventually end up
in paravirt_patch_default(). This function _will_ write direct
alternatives.

Signed-off-by: Peter Zijlstra (Intel) <peterz@...radead.org>