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Message-ID: <d28a9bf0-65ac-797c-3640-8af7e0beec33@linux.vnet.ibm.com>
Date:   Tue, 24 May 2022 16:23:55 +0530
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Subject: Re: [RFC PATCH 2/4] objtool: Enable objtool to run only on files with
 ftrace enabled
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To:     Christophe Leroy <christophe.leroy@csgroup.eu>,
        "linuxppc-dev@lists.ozlabs.org" <linuxppc-dev@lists.ozlabs.org>
Cc:     "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        "jpoimboe@redhat.com" <jpoimboe@redhat.com>,
        "peterz@infradead.org" <peterz@infradead.org>,
        "mbenes@suse.cz" <mbenes@suse.cz>, "aik@ozlabs.ru" <aik@ozlabs.ru>,
        "mpe@ellerman.id.au" <mpe@ellerman.id.au>,
        "rostedt@goodmis.org" <rostedt@goodmis.org>,
        "naveen.n.rao@linux.vnet.ibm.com" <naveen.n.rao@linux.vnet.ibm.com>,
        Sathvika Vasireddy <sv@linux.ibm.com>
References: <20220523175548.922671-1-sv@linux.ibm.com>
 <20220523175548.922671-3-sv@linux.ibm.com>
 <89012c4c-e989-6092-d4f1-0dc4eca983f1@csgroup.eu>
From:   Sathvika Vasireddy <sv@linux.vnet.ibm.com>
In-Reply-To: <89012c4c-e989-6092-d4f1-0dc4eca983f1@csgroup.eu>
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Hi Christophe,

On 24/05/22 14:27, Christophe Leroy wrote:
>
> Le 23/05/2022 à 19:55, Sathvika Vasireddy a écrit :
>> This patch makes sure objtool runs only on the object files
>> that have ftrace enabled, instead of running on all the object
>> files.
> Why do that ?
This was done to address the issue discussed here:
https://lore.kernel.org/all/b06bb9bc-22d1-acce-fe68-c7c4cb7c15b5@csgroup.eu/ 

>
> What about static_calls ? There may be files without ftrace but with
> static calls.
Yes, this prevents objtool from running on those files. We can
restrict this change to FTRACE_MCOUNT_USE_OBJTOOL
>
> By the way, it would be nice if we could use it only on C files.
> I get the following errors for ASM files:
>
> arch/powerpc/kernel/entry_32.o: warning: objtool: .text+0x1b4:
> unannotated intra-function call

I'm looking into ways to address this.

- Sathvika