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Date:   Mon, 5 Sep 2022 15:43:00 -0500
From:   Segher Boessenkool <segher@kernel.crashing.org>
To:     "Naveen N. Rao" <naveen.n.rao@linux.vnet.ibm.com>
Cc:     Christophe Leroy <christophe.leroy@csgroup.eu>,
        "aik@ozlabs.ru" <aik@ozlabs.ru>,
        "chenzhongjin@huawei.com" <chenzhongjin@huawei.com>,
        "jpoimboe@redhat.com" <jpoimboe@redhat.com>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        "linuxppc-dev@lists.ozlabs.org" <linuxppc-dev@lists.ozlabs.org>,
        "mbenes@suse.cz" <mbenes@suse.cz>,
        "mingo@redhat.com" <mingo@redhat.com>,
        "npiggin@gmail.com" <npiggin@gmail.com>,
        "peterz@infradead.org" <peterz@infradead.org>,
        "rostedt@goodmis.org" <rostedt@goodmis.org>,
        Sathvika Vasireddy <sv@linux.ibm.com>
Subject: Re: [PATCH v2 16/16] objtool/powerpc: Add --mcount specific implementation
Message-ID: <20220905204300.GC25951@gate.crashing.org>
References: <20220829055223.24767-1-sv@linux.ibm.com> <20220829055223.24767-17-sv@linux.ibm.com> <5da86617-53f1-d899-336a-53fe691e76ae@csgroup.eu> <20220831175100.GS25951@gate.crashing.org> <1662374555.7eoowv9twf.naveen@linux.ibm.com>
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Hi!

On Mon, Sep 05, 2022 at 04:15:07PM +0530, Naveen N. Rao wrote:
> Segher Boessenkool wrote:
> >>> +		if ((insn & 3) == 1) {
> >>> +			*type = INSN_CALL;
> >>> +			*immediate = insn & 0x3fffffc;
> >>> +			if (*immediate & 0x2000000)
> >>> +				*immediate -= 0x4000000;
> >>> +		}
> >>> +		break;
> >>> +	}
> >
> >Does this handle AA=1 correctly at all?  That is valid both with and
> >without relocations, just like AA=0.  Same for AA=1 LK=0 btw.
> >
> >If you only handle AA=0, the code should explicitly test for that.
> 
> The code does test for AA=0 LK=1 with the if statement there?

Yes, but that is not what I said :-)

It may be fine to not *handle* AA=1 at all, but the code should at least
scream bloody murder when it encounters it anyway :-)


Segher