From: Arnd Bergmann <arnd@arndb.de>
To: "Pali Rohár" <pali.rohar@gmail.com>
Cc: "Nicolas Pitre" <nicolas.pitre@linaro.org>,
"Tony Lindgren" <tony@atomide.com>,
"Russell King - ARM Linux" <linux@arm.linux.org.uk>,
linux-arm-kernel@lists.infradead.org,
"devicetree@vger.kernel.org" <devicetree@vger.kernel.org>,
"Ivaylo Dimitrov" <ivo.g.dimitrov.75@gmail.com>,
"Laura Abbott" <lauraa@codeaurora.org>,
"Sebastian Reichel" <sre@debian.org>,
"Will Deacon" <will.deacon@arm.com>,
linux-kernel@vger.kernel.org,
"Rob Herring" <robherring2@gmail.com>,
"Pavel Machek" <pavel@ucw.cz>,
"Grant Likely" <grant.likely@linaro.org>,
linux-omap@vger.kernel.org,
"Frank Rowand" <frowand.list@gmail.com>,
"Andreas Färber" <afaerber@suse.de>
Subject: Re: [PATCH 5/5] arm: boot: store ATAGs structure into DT "/chosen/linux,atags" entry
Date: Tue, 15 Dec 2015 12:04:35 +0100 [thread overview]
Message-ID: <1684644.M9TF75k3RB@wuerfel> (raw)
In-Reply-To: <20151215093325.GK13531@pali>
On Tuesday 15 December 2015 10:33:25 Pali Rohár wrote:
> On Monday 30 November 2015 11:09:42 Nicolas Pitre wrote:
> > On Mon, 30 Nov 2015, Pali Rohár wrote:
> > > On Monday 30 November 2015 07:23:53 Tony Lindgren wrote:
> > > > * Pali Rohár <pali.rohar@gmail.com> [151129 16:16]:
> > > > > On Monday 30 November 2015 01:09:17 Nicolas Pitre wrote:
> > > > > > On Sun, 29 Nov 2015, Russell King - ARM Linux wrote:
> > > In arch/arm/kernel/setup.c is function setup_arch() and it calls:
> > >
> > > mdesc = setup_machine_fdt(__atags_pointer);
> > > if (!mdesc)
> > > mdesc = setup_machine_tags(__atags_pointer, __machine_arch_type);
> > >
> > > So it looks like that on atags address is stored either atags structure
> > > or DT structure... so it is truth kernel uncompress code put DT blob to
> > > same offset where is expected atags structure?
> >
> > No. It doesn't put it anywhere. Those functions read DT/ATAGs from the
> > passed address. But you know this address won't be the one you want for
> > the legacy ATAGs.
> >
> > What you should do is to add a init_early hook to your mdesc structure
> > and retrieve your ATAGs from there directly at PAGE_OFFSET + 0x100.
> >
> > Now I suspect paging_init() marks the point where the ATAGs will be
> > overwritten. To prevent this, you might have to add an additional tweak
> > in arm_mm_memblock_reserve() similar to the one already present for
> > CONFIG_SA1111. Something like:
> >
> > memblock_reserve(PHYS_OFFSET, PAGE_SIZE);
> >
> > And later on you can return that page back to the system.
> >
>
> So am I understand correctly that solution would be to hack
> arch/arm/mm/mmu.c to not overwrite page at PHYS_OFFSET?
I would think we can just copy the data from PAGE_OFFSET + 0x100
to a some other page from your init_early hook. IIRC you can't use
kmalloc there, but memblock_alloc() should work.
Arnd
WARNING: multiple messages have this Message-ID (diff)
From: arnd@arndb.de (Arnd Bergmann)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH 5/5] arm: boot: store ATAGs structure into DT "/chosen/linux, atags" entry
Date: Tue, 15 Dec 2015 12:04:35 +0100 [thread overview]
Message-ID: <1684644.M9TF75k3RB@wuerfel> (raw)
In-Reply-To: <20151215093325.GK13531@pali>
On Tuesday 15 December 2015 10:33:25 Pali Roh?r wrote:
> On Monday 30 November 2015 11:09:42 Nicolas Pitre wrote:
> > On Mon, 30 Nov 2015, Pali Roh?r wrote:
> > > On Monday 30 November 2015 07:23:53 Tony Lindgren wrote:
> > > > * Pali Roh?r <pali.rohar@gmail.com> [151129 16:16]:
> > > > > On Monday 30 November 2015 01:09:17 Nicolas Pitre wrote:
> > > > > > On Sun, 29 Nov 2015, Russell King - ARM Linux wrote:
> > > In arch/arm/kernel/setup.c is function setup_arch() and it calls:
> > >
> > > mdesc = setup_machine_fdt(__atags_pointer);
> > > if (!mdesc)
> > > mdesc = setup_machine_tags(__atags_pointer, __machine_arch_type);
> > >
> > > So it looks like that on atags address is stored either atags structure
> > > or DT structure... so it is truth kernel uncompress code put DT blob to
> > > same offset where is expected atags structure?
> >
> > No. It doesn't put it anywhere. Those functions read DT/ATAGs from the
> > passed address. But you know this address won't be the one you want for
> > the legacy ATAGs.
> >
> > What you should do is to add a init_early hook to your mdesc structure
> > and retrieve your ATAGs from there directly at PAGE_OFFSET + 0x100.
> >
> > Now I suspect paging_init() marks the point where the ATAGs will be
> > overwritten. To prevent this, you might have to add an additional tweak
> > in arm_mm_memblock_reserve() similar to the one already present for
> > CONFIG_SA1111. Something like:
> >
> > memblock_reserve(PHYS_OFFSET, PAGE_SIZE);
> >
> > And later on you can return that page back to the system.
> >
>
> So am I understand correctly that solution would be to hack
> arch/arm/mm/mmu.c to not overwrite page at PHYS_OFFSET?
I would think we can just copy the data from PAGE_OFFSET + 0x100
to a some other page from your init_early hook. IIRC you can't use
kmalloc there, but memblock_alloc() should work.
Arnd
next prev parent reply other threads:[~2015-12-15 11:05 UTC|newest]
Thread overview: 160+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-07-06 20:26 [PATCH 0/5] ATAGs to DT patches Pali Rohár
2015-07-06 20:26 ` Pali Rohár
2015-07-06 20:26 ` [PATCH 1/5] arm: devtree: Set system_rev from DT "/revision" Pali Rohár
2015-07-06 20:26 ` Pali Rohár
2015-07-06 20:26 ` Pali Rohár
2015-12-24 19:02 ` Pali Rohár
2015-12-24 19:02 ` Pali Rohár
2015-12-24 19:02 ` Pali Rohár
2015-12-28 21:01 ` Frank Rowand
2015-12-28 21:01 ` Frank Rowand
2015-12-28 21:01 ` Frank Rowand
2015-12-28 22:27 ` Arnd Bergmann
2015-12-28 22:27 ` Arnd Bergmann
2015-12-28 22:27 ` Arnd Bergmann
2016-01-05 11:37 ` Pali Rohár
2016-01-05 11:37 ` Pali Rohár
2016-01-05 11:37 ` Pali Rohár
2016-01-05 11:37 ` Pali Rohár
2016-01-05 11:45 ` Arnd Bergmann
2016-01-05 11:45 ` Arnd Bergmann
2016-01-05 11:45 ` Arnd Bergmann
2016-02-05 18:15 ` [PATCH] ARM: RX51: Set system_rev from ATAGS Ivaylo Dimitrov
2016-02-05 18:15 ` Ivaylo Dimitrov
2016-02-08 20:48 ` Tony Lindgren
2016-02-08 20:48 ` Tony Lindgren
2016-02-08 21:10 ` Pali Rohár
2016-02-08 21:10 ` Pali Rohár
2016-02-09 16:17 ` Tony Lindgren
2016-02-09 16:17 ` Tony Lindgren
2016-02-10 18:23 ` [PATCH v1] " Ivaylo Dimitrov
2016-02-10 18:23 ` Ivaylo Dimitrov
2016-02-11 0:19 ` Tony Lindgren
2016-02-11 0:19 ` Tony Lindgren
2015-07-06 20:26 ` [PATCH 2/5] arm: boot: convert ATAG_REVISION to DT "/revision" entry Pali Rohár
2015-07-06 20:26 ` Pali Rohár
2015-07-06 20:26 ` Pali Rohár
2015-07-06 20:26 ` [PATCH 3/5] arm: atags: Fix declaration of function save_atags Pali Rohár
2015-07-06 20:26 ` Pali Rohár
2015-07-06 20:26 ` [PATCH 4/5] arm: devtree: Read ATAGs structure from DT "/chosen/linux,atags" entry Pali Rohár
2015-07-06 20:26 ` [PATCH 4/5] arm: devtree: Read ATAGs structure from DT "/chosen/linux, atags" entry Pali Rohár
2015-07-06 20:26 ` [PATCH 5/5] arm: boot: store ATAGs structure into DT "/chosen/linux,atags" entry Pali Rohár
2015-07-06 20:26 ` [PATCH 5/5] arm: boot: store ATAGs structure into DT "/chosen/linux, atags" entry Pali Rohár
2015-07-07 11:32 ` [PATCH 5/5] arm: boot: store ATAGs structure into DT "/chosen/linux,atags" entry Russell King - ARM Linux
2015-07-07 11:32 ` Russell King - ARM Linux
2015-07-07 11:58 ` Pali Rohár
2015-07-07 11:58 ` Pali Rohár
2015-07-13 13:19 ` Tony Lindgren
2015-07-13 13:19 ` Tony Lindgren
2015-10-12 20:16 ` Tony Lindgren
2015-10-12 20:16 ` Tony Lindgren
2015-10-12 20:25 ` Pali Rohár
2015-10-12 20:25 ` [PATCH 5/5] arm: boot: store ATAGs structure into DT "/chosen/linux, atags" entry Pali Rohár
2015-10-12 20:45 ` [PATCH 5/5] arm: boot: store ATAGs structure into DT "/chosen/linux,atags" entry Tony Lindgren
2015-10-12 20:45 ` Tony Lindgren
2015-10-13 14:37 ` Pali Rohár
2015-10-13 14:37 ` Pali Rohár
2015-11-05 11:40 ` Pali Rohár
2015-11-05 11:40 ` Pali Rohár
2015-11-05 16:17 ` Tony Lindgren
2015-11-05 16:17 ` Tony Lindgren
2015-11-12 1:10 ` Frank Rowand
2015-11-12 1:10 ` [PATCH 5/5] arm: boot: store ATAGs structure into DT "/chosen/linux, atags" entry Frank Rowand
2015-11-22 6:51 ` [PATCH 5/5] arm: boot: store ATAGs structure into DT "/chosen/linux,atags" entry Pavel Machek
2015-11-22 6:51 ` Pavel Machek
2015-11-23 14:45 ` Pali Rohár
2015-11-23 14:45 ` Pali Rohár
2015-11-23 14:45 ` Pali Rohár
2015-11-25 18:16 ` Tony Lindgren
2015-11-25 18:16 ` Tony Lindgren
2015-11-25 18:16 ` Tony Lindgren
2015-11-25 19:48 ` Arnd Bergmann
2015-11-25 19:48 ` [PATCH 5/5] arm: boot: store ATAGs structure into DT "/chosen/linux, atags" entry Arnd Bergmann
2015-11-25 21:03 ` [PATCH 5/5] arm: boot: store ATAGs structure into DT "/chosen/linux,atags" entry Tony Lindgren
2015-11-25 21:03 ` Tony Lindgren
2015-11-25 21:03 ` Tony Lindgren
2015-11-25 21:29 ` Arnd Bergmann
2015-11-25 21:29 ` [PATCH 5/5] arm: boot: store ATAGs structure into DT "/chosen/linux, atags" entry Arnd Bergmann
2015-11-25 21:44 ` [PATCH 5/5] arm: boot: store ATAGs structure into DT "/chosen/linux,atags" entry Pali Rohár
2015-11-25 21:44 ` [PATCH 5/5] arm: boot: store ATAGs structure into DT "/chosen/linux, atags" entry Pali Rohár
2015-11-25 21:44 ` [PATCH 5/5] arm: boot: store ATAGs structure into DT "/chosen/linux,atags" entry Pali Rohár
2015-11-25 21:51 ` Arnd Bergmann
2015-11-25 21:51 ` [PATCH 5/5] arm: boot: store ATAGs structure into DT "/chosen/linux, atags" entry Arnd Bergmann
2015-11-25 22:00 ` [PATCH 5/5] arm: boot: store ATAGs structure into DT "/chosen/linux,atags" entry Pali Rohár
2015-11-25 22:00 ` [PATCH 5/5] arm: boot: store ATAGs structure into DT "/chosen/linux, atags" entry Pali Rohár
2015-11-26 4:19 ` [PATCH 5/5] arm: boot: store ATAGs structure into DT "/chosen/linux,atags" entry Frank Rowand
2015-11-26 4:19 ` [PATCH 5/5] arm: boot: store ATAGs structure into DT "/chosen/linux, atags" entry Frank Rowand
2015-11-26 9:07 ` [PATCH 5/5] arm: boot: store ATAGs structure into DT "/chosen/linux,atags" entry Pali Rohár
2015-11-26 9:07 ` Pali Rohár
2015-11-26 20:39 ` Tony Lindgren
2015-11-26 20:39 ` Tony Lindgren
2015-11-26 20:39 ` Tony Lindgren
2015-11-26 21:12 ` Ivaylo Dimitrov
2015-11-26 21:12 ` Ivaylo Dimitrov
2015-11-27 8:38 ` Pali Rohár
2015-11-27 8:38 ` Pali Rohár
2015-11-27 8:44 ` Michael Trimarchi
2015-11-27 8:44 ` Michael Trimarchi
2015-11-27 8:44 ` Michael Trimarchi
2015-11-27 8:52 ` Michael Trimarchi
2015-11-27 8:52 ` Michael Trimarchi
2015-11-27 14:51 ` Tony Lindgren
2015-11-27 14:51 ` Tony Lindgren
2015-11-27 13:27 ` Russell King - ARM Linux
2015-11-27 13:27 ` Russell King - ARM Linux
2015-11-27 19:51 ` Russell King - ARM Linux
2015-11-27 19:51 ` Russell King - ARM Linux
2015-11-27 19:51 ` Russell King - ARM Linux
2015-11-27 21:06 ` Arnd Bergmann
2015-11-27 21:06 ` [PATCH 5/5] arm: boot: store ATAGs structure into DT "/chosen/linux, atags" entry Arnd Bergmann
2015-11-27 23:28 ` [PATCH 5/5] arm: boot: store ATAGs structure into DT "/chosen/linux,atags" entry Nicolas Pitre
2015-11-27 23:28 ` Nicolas Pitre
2015-11-27 23:28 ` Nicolas Pitre
2015-11-28 12:27 ` Arnd Bergmann
2015-11-28 12:27 ` [PATCH 5/5] arm: boot: store ATAGs structure into DT "/chosen/linux, atags" entry Arnd Bergmann
2015-11-28 12:27 ` [PATCH 5/5] arm: boot: store ATAGs structure into DT "/chosen/linux,atags" entry Arnd Bergmann
2015-11-28 12:54 ` Russell King - ARM Linux
2015-11-28 12:54 ` Russell King - ARM Linux
2015-11-28 12:54 ` Russell King - ARM Linux
2015-11-28 12:33 ` Russell King - ARM Linux
2015-11-28 12:33 ` Russell King - ARM Linux
2015-11-28 17:34 ` Nicolas Pitre
2015-11-28 17:34 ` Nicolas Pitre
2015-11-28 21:02 ` Frank Rowand
2015-11-28 21:02 ` [PATCH 5/5] arm: boot: store ATAGs structure into DT "/chosen/linux, atags" entry Frank Rowand
2015-11-28 21:02 ` [PATCH 5/5] arm: boot: store ATAGs structure into DT "/chosen/linux,atags" entry Frank Rowand
2015-11-29 18:09 ` Russell King - ARM Linux
2015-11-29 18:09 ` Russell King - ARM Linux
2015-11-29 18:09 ` Russell King - ARM Linux
2015-11-29 18:19 ` Pali Rohár
2015-11-29 18:19 ` [PATCH 5/5] arm: boot: store ATAGs structure into DT "/chosen/linux, atags" entry Pali Rohár
2015-11-29 23:13 ` [PATCH 5/5] arm: boot: store ATAGs structure into DT "/chosen/linux,atags" entry Russell King - ARM Linux
2015-11-29 23:13 ` Russell King - ARM Linux
2015-11-30 0:09 ` Nicolas Pitre
2015-11-30 0:09 ` Nicolas Pitre
2015-11-30 0:15 ` Pali Rohár
2015-11-30 0:15 ` [PATCH 5/5] arm: boot: store ATAGs structure into DT "/chosen/linux, atags" entry Pali Rohár
2015-11-30 0:15 ` [PATCH 5/5] arm: boot: store ATAGs structure into DT "/chosen/linux,atags" entry Pali Rohár
2015-11-30 15:23 ` Tony Lindgren
2015-11-30 15:23 ` Tony Lindgren
2015-11-30 15:23 ` Tony Lindgren
2015-11-30 15:39 ` Pali Rohár
2015-11-30 15:39 ` Pali Rohár
2015-11-30 15:39 ` Pali Rohár
2015-11-30 16:09 ` Nicolas Pitre
2015-11-30 16:09 ` Nicolas Pitre
2015-12-15 9:33 ` Pali Rohár
2015-12-15 9:33 ` Pali Rohár
2015-12-15 11:04 ` Arnd Bergmann [this message]
2015-12-15 11:04 ` [PATCH 5/5] arm: boot: store ATAGs structure into DT "/chosen/linux, atags" entry Arnd Bergmann
2015-12-15 12:20 ` [PATCH 5/5] arm: boot: store ATAGs structure into DT "/chosen/linux,atags" entry Russell King - ARM Linux
2015-12-15 12:20 ` Russell King - ARM Linux
2015-12-15 17:24 ` Nicolas Pitre
2015-12-15 17:24 ` Nicolas Pitre
2015-12-15 17:24 ` Nicolas Pitre
2015-12-23 14:54 ` Ivaylo Dimitrov
2015-12-23 14:54 ` Ivaylo Dimitrov
2015-11-28 4:06 ` [PATCH 0/5] ATAGs to DT patches Frank Rowand
2015-11-28 4:06 ` Frank Rowand
2015-11-28 5:55 ` Frank Rowand
2015-11-28 5:55 ` Frank Rowand
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