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From: David Hildenbrand <david@redhat.com>
To: Mike Rapoport <rppt@linux.ibm.com>, Alex Ghiti <alex@ghiti.fr>
Cc: Paul Walmsley <paul.walmsley@sifive.com>,
	Palmer Dabbelt <palmer@dabbelt.com>,
	Albert Ou <aou@eecs.berkeley.edu>,
	linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org,
	linux-arch@vger.kernel.org, linux-mm@kvack.org,
	Vitaly Wool <vitaly.wool@konsulko.com>
Subject: Re: [PATCH v7] RISC-V: enable XIP
Date: Fri, 9 Apr 2021 14:46:17 +0200	[thread overview]
Message-ID: <e7e87306-bb04-2d4f-7e7f-aabd40dccb3b@redhat.com> (raw)
In-Reply-To: <YHBEsDuEvPAnL8Vb@linux.ibm.com>

>>> Also, will that memory properly be exposed in the resource tree as
>>> System RAM (e.g., /proc/iomem) ? Otherwise some things (/proc/kcore)
>>> won't work as expected - the kernel won't be included in a dump.
>   
> Do we really need a XIP kernel to included in kdump?
> And does not it sound weird to expose flash as System RAM in /proc/iomem? ;-)

See my other mail, maybe we actually want something different.

> 
>> I have just checked and it does not appear in /proc/iomem.
>>
>> Ok your conclusion would be to have struct page, I'm going to implement this
>> version then using memblock as you described.
> 
> I'm not sure this is required. With XIP kernel text never gets into RAM, so
> it does not seem to require struct page.
> 
> XIP by definition has some limitations relatively to "normal" operation,
> so lack of kdump could be one of them.

I agree.

> 
> I might be wrong, but IMHO, artificially creating a memory map for part of
> flash would cause more problems in the long run.

Can you elaborate?

> 
> BTW, how does XIP account the kernel text on other architectures that
> implement it?

Interesting point, I thought XIP would be something new on RISC-V (well, 
at least to me :) ). If that concept exists already, we better mimic 
what existing implementations do.

-- 
Thanks,

David / dhildenb


  reply	other threads:[~2021-04-09 12:46 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-04-09  6:51 [PATCH v7] RISC-V: enable XIP Alexandre Ghiti
2021-04-09  7:14 ` Alex Ghiti
2021-04-09  8:23   ` David Hildenbrand
2021-04-09 11:39     ` Alex Ghiti
2021-04-09 12:07       ` David Hildenbrand
2021-04-09 12:57         ` Alex Ghiti
2021-04-09 14:10         ` Mike Rapoport
2021-04-09 14:16           ` David Hildenbrand
2021-04-09 12:12       ` Mike Rapoport
2021-04-09 12:46         ` David Hildenbrand [this message]
2021-04-09 13:59           ` Mike Rapoport
2021-04-09 14:10             ` David Hildenbrand
2021-04-09 14:42             ` Vitaly Wool
2021-04-12  5:12               ` Alex Ghiti
2021-04-12  7:49                 ` Vitaly Wool

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