[bug report]warning about entry_64.S from objtool in v5.4 LTS

From: Xinghui Li
Date: Sun Feb 05 2023 - 22:08:58 EST


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 “x86/speculation: Change
FILL_RETURN_BUFFER to work with objtool( commit 8afd1c7da2)”backported
in v5.4.217.
Comparing with the upstream version(commit 089dd8e53):
There is no “ANNOTATE_INTRA_FUNCTION_CALL” in v5.4 for missing
dependency patch. When the “ANNOTATE_NOSPEC_ALTERNATIVE” is removed,
this issue just occurs.

I tried to backport “ANNOTATE_INTRA_FUNCTION_CALL”and its dependency
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.