MIME-Version: 1.0
From:   Xinghui Li <korantwork@gmail.com>
Date:   Mon, 6 Feb 2023 11:09:48 +0800
Message-ID: <CAEm4hYXr28O8TOmZWEKfp-00Y9R7Ky7C6X3JTtfm-0AD42KbrA@mail.gmail.com>
Subject: [bug report]warning about entry_64.S from objtool in v5.4 LTS
To:     peterz@infradead.org, jpoimboe@redhat.com, tglx@linutronix.de
Cc:     stable@vger.kernel.org, linux-kernel@vger.kernel.org,
        x86@kernel.org, alexs@kernel.org
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Hi all
We found a warning from objtool:
arch/x86/entry/entry_64.o: warning: objtool: .entry.text+0x1d1:
unsupported intra-function call

and if we enable retpoline in config:
arch/x86/entry/entry_64.o: warning: objtool: .entry.text+0x1c1:
unsupported intra-function call
arch/x86/entry/entry_64.o: warning: objtool: If this is a retpoline,
please patch it in with alternatives and annotate it with
ANNOTATE_NOSPEC_ALTERNATIVE.

I found this issue has been introduced since =E2=80=9Cx86/speculation: Chan=
ge
FILL_RETURN_BUFFER to work with objtool( commit 8afd1c7da2)=E2=80=9Dbackpor=
ted
in v5.4.217.
Comparing with the upstream version(commit 089dd8e53):
There is no =E2=80=9CANNOTATE_INTRA_FUNCTION_CALL=E2=80=9D in v5.4 for miss=
ing
dependency patch. When the =E2=80=9CANNOTATE_NOSPEC_ALTERNATIVE=E2=80=9D is=
 removed,
this issue just occurs.

I tried to backport =E2=80=9CANNOTATE_INTRA_FUNCTION_CALL=E2=80=9Dand its d=
ependency
patchs in v5.4, but I met the CFA miss match issue from objtool.
So, please help check this issue in v5.4 LTS version.