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From: Pavel Tatashin <pasha.tatashin@soleen.com>
To: James Morse <james.morse@arm.com>
Cc: Sasha Levin <sashal@kernel.org>,
	Mark Rutland <mark.rutland@arm.com>,
	Vladimir Murzin <vladimir.murzin@arm.com>,
	Jonathan Corbet <corbet@lwn.net>,
	Marc Zyngier <marc.zyngier@arm.com>,
	Catalin Marinas <catalin.marinas@arm.com>,
	Bhupesh Sharma <bhsharma@redhat.com>,
	kexec mailing list <kexec@lists.infradead.org>,
	LKML <linux-kernel@vger.kernel.org>,
	James Morris <jmorris@namei.org>, linux-mm <linux-mm@kvack.org>,
	"Eric W. Biederman" <ebiederm@xmission.com>,
	Matthias Brugger <matthias.bgg@gmail.com>,
	will@kernel.org, Linux ARM <linux-arm-kernel@lists.infradead.org>
Subject: Re: [PATCH v3 07/17] arm64, hibernate: move page handling function to new trans_pgd.c
Date: Fri, 6 Sep 2019 13:41:17 -0400	[thread overview]
Message-ID: <CA+CK2bDTVGm6pNRGQx7eAyEP6m0xr9X1No_=qgUOTDAoL9uigw@mail.gmail.com> (raw)
In-Reply-To: <f1db863a-de57-2d1a-6bec-6020b2130964@arm.com>

On Fri, Sep 6, 2019 at 11:18 AM James Morse <james.morse@arm.com> wrote:
>
> Hi Pavel,
>
> On 21/08/2019 19:31, Pavel Tatashin wrote:
> > Now, that we abstracted the required functions move them to a new home.
> > Later, we will generalize these function in order to be useful outside
> > of hibernation.
>
> > diff --git a/arch/arm64/mm/trans_pgd.c b/arch/arm64/mm/trans_pgd.c
> > new file mode 100644
> > index 000000000000..00b62d8640c2
> > --- /dev/null
> > +++ b/arch/arm64/mm/trans_pgd.c
> > @@ -0,0 +1,211 @@
> > +// SPDX-License-Identifier: GPL-2.0
> > +
> > +/*
> > + * Copyright (c) 2019, Microsoft Corporation.
> > + * Pavel Tatashin <patatash@linux.microsoft.com>
>
> Hmmm, while line-count isn't a useful metric: this file contains 41% of the code that was
> in hibernate.c, but has stripped the substantial copyright-pedigree that the hibernate
> code had built up over the years.
> (counting lines identified by 'cloc' as code, not comments or blank)
>
> If you are copying or moving a non trivial quantity of code, you need to preserve the
> copyright. Something like 'Derived from the arm64 hibernate support which has:'....

I will do that.  The copyright thing was meant to appear in
"generalization" patch that comes later, where I unified most of the
code to be symmetric.
So, I will add it there, and also do the derived message that you suggested.

>
>
> > + */
> > +
> > +/*
> > + * Transitional tables are used during system transferring from one world to
> > + * another: such as during hibernate restore, and kexec reboots. During these
> > + * phases one cannot rely on page table not being overwritten.
>
> I think you need to mention that hibernate and kexec are rewriting memory, and may
> overwrite the live page tables, therefore ...

Will add, thank you.

Pasha

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  reply	other threads:[~2019-09-06 17:41 UTC|newest]

Thread overview: 44+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-08-21 18:31 [PATCH v3 00/17] arm64: MMU enabled kexec relocation Pavel Tatashin
2019-08-21 18:31 ` [PATCH v3 01/17] kexec: quiet down kexec reboot Pavel Tatashin
2019-09-06 15:17   ` James Morse
2019-09-06 15:35     ` Pavel Tatashin
2019-08-21 18:31 ` [PATCH v3 02/17] arm64, hibernate: use get_safe_page directly Pavel Tatashin
2019-09-06 15:17   ` James Morse
2019-09-06 15:39     ` Pavel Tatashin
2019-08-21 18:31 ` [PATCH v3 03/17] arm64, hibernate: remove gotos in create_safe_exec_page Pavel Tatashin
2019-09-06 15:17   ` James Morse
2019-09-06 15:41     ` Pavel Tatashin
2019-08-21 18:31 ` [PATCH v3 04/17] arm64, hibernate: rename dst to page " Pavel Tatashin
2019-09-06 15:17   ` James Morse
2019-09-06 15:41     ` Pavel Tatashin
2019-08-21 18:31 ` [PATCH v3 05/17] arm64, hibernate: check pgd table allocation Pavel Tatashin
2019-09-06 15:17   ` James Morse
2019-09-06 15:44     ` Pavel Tatashin
2019-08-21 18:31 ` [PATCH v3 06/17] arm64, hibernate: add trans_pgd public functions Pavel Tatashin
2019-09-06 15:18   ` James Morse
2019-09-06 16:00     ` Pavel Tatashin
2019-10-11 18:16       ` James Morse
2019-08-21 18:31 ` [PATCH v3 07/17] arm64, hibernate: move page handling function to new trans_pgd.c Pavel Tatashin
2019-09-06 15:18   ` James Morse
2019-09-06 17:41     ` Pavel Tatashin [this message]
2019-08-21 18:31 ` [PATCH v3 08/17] arm64, trans_pgd: make trans_pgd_map_page generic Pavel Tatashin
2019-09-06 15:20   ` James Morse
2019-09-06 18:58     ` Pavel Tatashin
2019-10-11 18:15       ` James Morse
2019-08-21 18:31 ` [PATCH v3 09/17] arm64, trans_pgd: add trans_pgd_create_empty Pavel Tatashin
2019-09-06 15:20   ` James Morse
2019-09-06 19:00     ` Pavel Tatashin
2019-08-21 18:31 ` [PATCH v3 10/17] arm64, trans_pgd: adjust trans_pgd_create_copy interface Pavel Tatashin
2019-09-06 15:20   ` James Morse
2019-09-06 19:03     ` Pavel Tatashin
2019-08-21 18:31 ` [PATCH v3 11/17] arm64, trans_pgd: add PUD_SECT_RDONLY Pavel Tatashin
2019-09-06 15:21   ` James Morse
2019-09-06 19:04     ` Pavel Tatashin
2019-08-21 18:31 ` [PATCH v3 12/17] arm64, trans_pgd: complete generalization of trans_pgds Pavel Tatashin
2019-09-06 15:23   ` James Morse
2019-09-06 19:06     ` Pavel Tatashin
2019-08-21 18:32 ` [PATCH v3 13/17] kexec: add machine_kexec_post_load() Pavel Tatashin
2019-08-21 18:32 ` [PATCH v3 14/17] arm64, kexec: move relocation function setup and clean up Pavel Tatashin
2019-08-21 18:32 ` [PATCH v3 15/17] arm64, kexec: add expandable argument to relocation function Pavel Tatashin
2019-08-21 18:32 ` [PATCH v3 16/17] arm64, kexec: configure trans_pgd page table for kexec Pavel Tatashin
2019-08-21 18:32 ` [PATCH v3 17/17] arm64, kexec: enable MMU during kexec relocation Pavel Tatashin

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