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Message-ID: <38546223-7585-bfad-b553-9739d31d7fbf@linux.microsoft.com>
Date:   Wed, 1 Jun 2022 17:45:20 -0500
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Subject: Re: [RFC PATCH v2 09/20] objtool: arm64: Implement command to invoke
 the decoder
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To:     Peter Zijlstra <peterz@infradead.org>
Cc:     Mark Brown <broonie@kernel.org>, jpoimboe@redhat.com,
        chenzhongjin@huawei.com, mark.rutland@arm.com,
        nobuta.keiya@fujitsu.com, sjitindarsingh@gmail.com,
        catalin.marinas@arm.com, will@kernel.org,
        jamorris@linux.microsoft.com, linux-arm-kernel@lists.infradead.org,
        live-patching@vger.kernel.org, linux-kernel@vger.kernel.org
References: <e81e773678f88f7c2ff7480e2eb096973ec198db>
 <20220524001637.1707472-1-madvenka@linux.microsoft.com>
 <20220524001637.1707472-10-madvenka@linux.microsoft.com>
 <YoznLR30T+03Ea08@sirena.org.uk>
 <ff58b576-efee-276a-bfb3-11f5d258d580@linux.microsoft.com>
 <YpR3naaNCNG9ZJGC@worktop.programming.kicks-ass.net>
From:   "Madhavan T. Venkataraman" <madvenka@linux.microsoft.com>
In-Reply-To: <YpR3naaNCNG9ZJGC@worktop.programming.kicks-ass.net>
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On 5/30/22 02:51, Peter Zijlstra wrote:
> On Sun, May 29, 2022 at 09:49:44AM -0500, Madhavan T. Venkataraman wrote:
>>
>>
>> On 5/24/22 09:09, Mark Brown wrote:
>>> On Mon, May 23, 2022 at 07:16:26PM -0500, madvenka@linux.microsoft.com wrote:
>>>> From: "Madhavan T. Venkataraman" <madvenka@linux.microsoft.com>
>>>>
>>>> Implement a built-in command called cmd_fpv() that can be invoked as
>>>> follows:
>>>>
>>>> 	objtool fpv generate file.o
>>>>
>>>> The built-in command invokes decode_instructions() to walk each function
>>>> and decode the instructions of the function.
>>>
>>> In commit b51277eb9775ce91 ("objtool: Ditch subcommands") Josh removed
>>> subcommands so this interface is going to need a rethink.
>>
>> Thanks for mentioning this. I will sync my patchset to the latest and send out version 3.
> 
> Before you do; why are you duplicating lots of validate_branch() ? Why
> can't you use the regular code to generate ORC data?
> 
> I'm really not happy about all this.

Hi Peter,

I am preparing a detailed response to this explaining why I have not used validate_branch().
The short answer is that no validation is required for my approach. But I will send my detailed
response shortly.

Thanks.

Madhavan