linux-kernel - Re: [PATCH 1/9] objtool,x86: Replace alternatives with .retpoline

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]

Message-ID: <20211013201135.ftaztysa4bdjedqd@treble>
Date:   Wed, 13 Oct 2021 13:11:35 -0700
From:   Josh Poimboeuf <jpoimboe@...hat.com>
To:     Peter Zijlstra <peterz@...radead.org>
Cc:     x86@...nel.org, andrew.cooper3@...rix.com,
        linux-kernel@...r.kernel.org, alexei.starovoitov@...il.com,
        ndesaulniers@...gle.com
Subject: Re: [PATCH 1/9] objtool,x86: Replace alternatives with
 .retpoline_sites

On Wed, Oct 13, 2021 at 02:22:18PM +0200, Peter Zijlstra wrote:
> Instead of writing complete alternatives, simply provide a list of all
> the retpoline thunk calls. Then the kernel is free to do with them as
> it pleases. Simpler code all-round.
> 
> Signed-off-by: Peter Zijlstra (Intel) <peterz@...radead.org>

+1, let the kernel patch its own damn self ;-)

> +int arch_rewrite_retpolines(struct objtool_file *file)

Guess it shouldn't be called arch_rewrite_retpolines() anymore.  And it
can be moved to check.c next to create_static_call_sections().

Also is it possible to remove the arch_is_retpoline() check in
get_alt_entry()?  I'm having trouble remembering why that was needed in
the first place.

-- 
Josh