Date:   Wed, 25 Jan 2023 12:57:35 +0530
From:   "Naveen N. Rao" <naveen.n.rao@linux.vnet.ibm.com>
Subject: Re: arch/powerpc/kernel/head_85xx.o: warning: objtool:
 .head.text+0x1a6c: unannotated intra-function call
To:     kernel test robot <lkp@intel.com>,
        Sathvika Vasireddy <sv@linux.ibm.com>
Cc:     Christophe Leroy <christophe.leroy@csgroup.eu>,
        linux-kernel@vger.kernel.org,
        Michael Ellerman <mpe@ellerman.id.au>,
        oe-kbuild-all@lists.linux.dev, linuxppc-dev@lists.ozlabs.org,
        npiggin@gmail.com
References: <202301161955.38kK6ksW-lkp@intel.com>
        <b2273730-f885-7658-7ec4-12fb5bfc515b@linux.ibm.com>
In-Reply-To: <b2273730-f885-7658-7ec4-12fb5bfc515b@linux.ibm.com>
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Sathvika Vasireddy wrote:
>=20
>>>> arch/powerpc/kvm/booke.o: warning: objtool: kvmppc_fill_pt_regs+0x30: =
unannotated intra-function call
>=20
> As an attempt to fix it, I tried expanding ANNOTATE_INTRA_FUNCTION_CALL=20
> macro to indicate that the branch target is valid. It then threw another=20
> warning (arch/powerpc/kvm/booke.o: warning: objtool:=20
> kvmppc_fill_pt_regs+0x38: intra_function_call not a direct call). The=20
> below diff just removes the warnings for me, but I'm not very sure if=20
> this is the best way to fix the objtool warnings seen with this=20
> particular file. Please let me know if there are any better ways to fix i=
t.
>=20
> diff --git a/arch/powerpc/kvm/booke.c b/arch/powerpc/kvm/booke.c
> index 0dce93ccaadf..b6a413824b98 100644
> --- a/arch/powerpc/kvm/booke.c
> +++ b/arch/powerpc/kvm/booke.c
> @@ -917,7 +917,9 @@ static void kvmppc_fill_pt_regs(struct pt_regs *regs)
>  =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 asm("mr %0, 1" : "=3Dr"(r1));
>  =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 asm("mflr %0" : "=3Dr"(lr));
>  =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 asm("mfmsr %0" : "=3Dr"(msr))=
;
> +=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 asm(".pushsection .discard.intra_fu=
nction_calls; .long 999f;=20
> .popsection; 999:");
>  =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 asm("bl 1f; 1: mflr %0" : "=
=3Dr"(ip));

I don't think you can assume that there won't be anything in between two=20
asm statements. Does it work if you combine both the above asm=20
statements into a single one?

Even if that works, I don't think it is good to expand the macro here. =20
That asm statement looks to be trying to grab the current nip. I don't=20
know enough about that code, and someone who knows more about KVM may be=20
able to help, but it looks like we should be able to simply set 'ip' to=20
the address of kvmppc_fill_pt_regs()?


- Naveen