linux-kernel - Re: [PATCH 1/2] x86/chacha20: Avoid spurious jumps to other functions

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Message-ID: <Yj1DlVIcO9da1HFa@gondor.apana.org.au>
Date:   Fri, 25 Mar 2022 16:22:45 +1200
From:   Herbert Xu <herbert@...dor.apana.org.au>
To:     Peter Zijlstra <peterz@...radead.org>
Cc:     x86@...nel.org, linux-kernel@...r.kernel.org,
        linux-crypto@...r.kernel.org, ebiggers@...gle.com, Jason@...c4.com,
        Josh Poimboeuf <jpoimboe@...hat.com>,
        Stephen Rothwell <sfr@...b.auug.org.au>
Subject: Re: [PATCH 1/2] x86/chacha20: Avoid spurious jumps to other functions

On Tue, Mar 22, 2022 at 12:48:10PM +0100, Peter Zijlstra wrote:
> The chacha_Nblock_xor_avx512vl() functions all have their own,
> identical, .LdoneN label, however in one particular spot {2,4} jump to
> the 8 version instead of their own. Resulting in:
> 
>   arch/x86/crypto/chacha-x86_64.o: warning: objtool: chacha_2block_xor_avx512vl() falls through to next function chacha_8block_xor_avx512vl()
>   arch/x86/crypto/chacha-x86_64.o: warning: objtool: chacha_4block_xor_avx512vl() falls through to next function chacha_8block_xor_avx512vl()
> 
> Make each function consistently use its own done label.
> 
> Reported-by: Stephen Rothwell <sfr@...b.auug.org.au>
> Signed-off-by: Peter Zijlstra (Intel) <peterz@...radead.org>
> ---
>  arch/x86/crypto/chacha-avx512vl-x86_64.S |    4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)

Patch applied.  Thanks.
-- 
Email: Herbert Xu <herbert@...dor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt