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

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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