Re: [PATCH v3 02/18] remoteproc: qcom: Move minidump specific data to qcom_minidump.h

From: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
To: Mukesh Ojha <quic_mojha@quicinc.com>,
	agross@kernel.org, andersson@kernel.org,
	konrad.dybcio@linaro.org, corbet@lwn.net, keescook@chromium.org,
	tony.luck@intel.com, gpiccoli@igalia.com,
	catalin.marinas@arm.com, will@kernel.org,
	krzysztof.kozlowski+dt@linaro.org, robh+dt@kernel.org,
	linus.walleij@linaro.org, linux-gpio@vger.kernel.org,
	srinivas.kandagatla@linaro.org
Cc: linux-arm-msm@vger.kernel.org, linux-remoteproc@vger.kernel.org,
	linux-kernel@vger.kernel.org, linux-hardening@vger.kernel.org,
	linux-arm-kernel@lists.infradead.org, linux-doc@vger.kernel.org
Subject: Re: [PATCH v3 02/18] remoteproc: qcom: Move minidump specific data to qcom_minidump.h
Date: Thu, 4 May 2023 14:36:40 +0200	[thread overview]
Message-ID: <1a4f4b55-6284-6149-4c7b-7b45fa1de291@linaro.org> (raw)
In-Reply-To: <33ea7c3b-4317-5aff-5e6a-af6e093d45a0@quicinc.com>

On 04/05/2023 14:26, Mukesh Ojha wrote:
> 
> 
> On 5/4/2023 5:33 PM, Krzysztof Kozlowski wrote:
>> On 04/05/2023 13:58, Mukesh Ojha wrote:
>>>
>>>
>>> On 5/4/2023 5:08 PM, Krzysztof Kozlowski wrote:
>>>> On 03/05/2023 19:02, Mukesh Ojha wrote:
>>>>> Move minidump specific data types and macros to a separate internal
>>>>> header(qcom_minidump.h) so that it can be shared among different
>>>>> Qualcomm drivers.
>>>>
>>>> No, this is not internal header. You moved it to global header.
>>>>
>>>> There is no reason driver internals should be exposed to other unrelated
>>>> subsystems.
>>>>
>>>>>
>>>>> There is no change in functional behavior after this.
>>>>
>>>> It is. You made all these internal symbols available to others.
>>>>
>>>>>
>>>>
>>>> This comes without justification why other drivers needs to access
>>>> private and internal data. It does not look correct design. NAK.
>>>
>>> Thanks for catching outdated commit text, will fix the commit with
>>> more descriptive reasoning.
>>>
>>> It has to be global so that co-processor minidump and apss minidump can
>>> share data structure and they are lying in different directory.
>>>
>>
>> Then you should not share all the internals of memory layout but only
>> few pieces necessary to talk with minidump driver. The minidump driver
>> should organize everything how it wants.
> 
> These are core data structure which is shared with boot firmware and the
> one's are moved here all are required by minidump driver .

I am not sure if I understand correctly. If they are all required by
minidump driver, then this must not be in include, but stay with
minidump. Remoteproc then should not touch it.

I don't understand why internals of minidump should be important for
remoteproc. If they are, means you broken encapsulation.

> 
> If you follow here[1], i raised by concern to make this particular one's
> as private and later to avoid confusion went with single header.
> But if others agree, I will keep the one that get shared with minidump
> as separate one or if relative path of headers are allowed that can make
> it private between these drivers(which i don't think, will be allowed or
> recommended).

Let's be specific: why MD_REGION_VALID must be available for remoteproc
or any other driver after introducing qcom minidump driver?

Best regards,
Krzysztof