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Subject: Re: [PATCH 06/17] prmem: test cases for memory protection
To:     Randy Dunlap <rdunlap@infradead.org>,
        Mimi Zohar <zohar@linux.vnet.ibm.com>,
        Kees Cook <keescook@chromium.org>,
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Cc:     igor.stoppa@huawei.com, Dave Hansen <dave.hansen@linux.intel.com>,
        Jonathan Corbet <corbet@lwn.net>,
        Laura Abbott <labbott@redhat.com>,
        Vlastimil Babka <vbabka@suse.cz>,
        "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        Pavel Tatashin <pasha.tatashin@oracle.com>, linux-mm@kvack.org,
        linux-kernel@vger.kernel.org
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 <20181023213504.28905-7-igor.stoppa@huawei.com>
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From:   Igor Stoppa <igor.stoppa@gmail.com>
Message-ID: <00461c0a-a214-1984-5614-c7a4a2a7ff83@gmail.com>
Date:   Wed, 24 Oct 2018 17:24:03 +0300
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Hi,

On 24/10/18 06:27, Randy Dunlap wrote:

> a. It seems backwards (or upside down) to have a test case select a feature (PRMEM)
> instead of depending on that feature.
> 
> b. Since PRMEM depends on MMU (in patch 04/17), the "select" here could try to
> enabled PRMEM even when MMU is not enabled.
> 
> Changing this to "depends on PRMEM" would solve both of these issues.

The weird dependency you pointed out is partially caused by the 
incompleteness of PRMEM.

What I have in mind is to have a fallback version of it for systems 
without MMU capable of write protection.
Possibly defaulting to kvmalloc.
In that case there would not be any need for a configuration option.

> c. Don't use "default n".  That is already the default.

ok

--
igor