From: Arnd Bergmann <arnd@arndb.de>
To: Mark Rutland <mark.rutland@arm.com>
Cc: linux-arm-kernel@lists.infradead.org, bhe@redhat.com,
linuxppc-dev@lists.ozlabs.org, kexec@lists.infradead.org,
linux-kernel@vger.kernel.org,
AKASHI Takahiro <takahiro.akashi@linaro.org>,
"Eric W. Biederman" <ebiederm@xmission.com>,
bauerman@linux.vnet.ibm.com, Dave Young <dyoung@redhat.com>,
Vivek Goyal <vgoyal@redhat.com>
Subject: Re: [RFC 0/3] extend kexec_file_load system call
Date: Wed, 13 Jul 2016 21:57:28 +0200 [thread overview]
Message-ID: <7927804.6bj1abO0d2@wuerfel> (raw)
In-Reply-To: <20160713175630.GA2668@leverpostej>
On Wednesday, July 13, 2016 6:58:32 PM CEST Mark Rutland wrote:
>
> > we may want to remove unnecessary devices and even add a dedicated
> > storage device for storing a core dump image.
>
> I suspect that bringing up a minimal number of devices is better
> controlled by a cmdline option. In general, figuring out what is
> necessary and what is not is going to be board specific, so hacking the
> FW tables (DTB or ACPI) is not a very portable/reliable approach.
>
> Do we actually add devices in practice? More so than the above that
> requires special knowledge of the platform (including things that were
> not described in the boot DTB).
>
> In the ACPI case modifying a DTB alone is not sufficient to change the
> information regarding devices, as those won't be described in the DTB.
> It's not possible to convert ACPI to DTB in general.
A more likely scenario would be replacing ACPI tables with a DTB that
describes the platform in order to use devices that the ACPI tables
don't contain.
> > - Say, booting BE kernel on ACPI LE kernel
> > In this case, there is no useful dtb in the kernel.
> If the platform only has ACPI, then you cannot boot a BE kernel to begin
> with. As above one cannot convert ACPI to DTB, so one would need
> extensive platform knowledge for this to work.
I think what he meant was to pass a DTB to the kexec kernel in order
to run BE, while the original kernel can only run LE due to ACPI.
If you boot a LE kernel using DTB, the same DTB should work
for a kexec boot for a BE kernel.
Arnd
_______________________________________________
kexec mailing list
kexec@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/kexec
WARNING: multiple messages have this Message-ID (diff)
From: Arnd Bergmann <arnd@arndb.de>
To: Mark Rutland <mark.rutland@arm.com>
Cc: AKASHI Takahiro <takahiro.akashi@linaro.org>,
Dave Young <dyoung@redhat.com>,
bhe@redhat.com, kexec@lists.infradead.org,
linux-kernel@vger.kernel.org, Vivek Goyal <vgoyal@redhat.com>,
"Eric W. Biederman" <ebiederm@xmission.com>,
bauerman@linux.vnet.ibm.com, linuxppc-dev@lists.ozlabs.org,
linux-arm-kernel@lists.infradead.org
Subject: Re: [RFC 0/3] extend kexec_file_load system call
Date: Wed, 13 Jul 2016 21:57:28 +0200 [thread overview]
Message-ID: <7927804.6bj1abO0d2@wuerfel> (raw)
In-Reply-To: <20160713175630.GA2668@leverpostej>
On Wednesday, July 13, 2016 6:58:32 PM CEST Mark Rutland wrote:
>
> > we may want to remove unnecessary devices and even add a dedicated
> > storage device for storing a core dump image.
>
> I suspect that bringing up a minimal number of devices is better
> controlled by a cmdline option. In general, figuring out what is
> necessary and what is not is going to be board specific, so hacking the
> FW tables (DTB or ACPI) is not a very portable/reliable approach.
>
> Do we actually add devices in practice? More so than the above that
> requires special knowledge of the platform (including things that were
> not described in the boot DTB).
>
> In the ACPI case modifying a DTB alone is not sufficient to change the
> information regarding devices, as those won't be described in the DTB.
> It's not possible to convert ACPI to DTB in general.
A more likely scenario would be replacing ACPI tables with a DTB that
describes the platform in order to use devices that the ACPI tables
don't contain.
> > - Say, booting BE kernel on ACPI LE kernel
> > In this case, there is no useful dtb in the kernel.
> If the platform only has ACPI, then you cannot boot a BE kernel to begin
> with. As above one cannot convert ACPI to DTB, so one would need
> extensive platform knowledge for this to work.
I think what he meant was to pass a DTB to the kexec kernel in order
to run BE, while the original kernel can only run LE due to ACPI.
If you boot a LE kernel using DTB, the same DTB should work
for a kexec boot for a BE kernel.
Arnd
WARNING: multiple messages have this Message-ID (diff)
From: arnd@arndb.de (Arnd Bergmann)
To: linux-arm-kernel@lists.infradead.org
Subject: [RFC 0/3] extend kexec_file_load system call
Date: Wed, 13 Jul 2016 21:57:28 +0200 [thread overview]
Message-ID: <7927804.6bj1abO0d2@wuerfel> (raw)
In-Reply-To: <20160713175630.GA2668@leverpostej>
On Wednesday, July 13, 2016 6:58:32 PM CEST Mark Rutland wrote:
>
> > we may want to remove unnecessary devices and even add a dedicated
> > storage device for storing a core dump image.
>
> I suspect that bringing up a minimal number of devices is better
> controlled by a cmdline option. In general, figuring out what is
> necessary and what is not is going to be board specific, so hacking the
> FW tables (DTB or ACPI) is not a very portable/reliable approach.
>
> Do we actually add devices in practice? More so than the above that
> requires special knowledge of the platform (including things that were
> not described in the boot DTB).
>
> In the ACPI case modifying a DTB alone is not sufficient to change the
> information regarding devices, as those won't be described in the DTB.
> It's not possible to convert ACPI to DTB in general.
A more likely scenario would be replacing ACPI tables with a DTB that
describes the platform in order to use devices that the ACPI tables
don't contain.
> > - Say, booting BE kernel on ACPI LE kernel
> > In this case, there is no useful dtb in the kernel.
> If the platform only has ACPI, then you cannot boot a BE kernel to begin
> with. As above one cannot convert ACPI to DTB, so one would need
> extensive platform knowledge for this to work.
I think what he meant was to pass a DTB to the kexec kernel in order
to run BE, while the original kernel can only run LE due to ACPI.
If you boot a LE kernel using DTB, the same DTB should work
for a kexec boot for a BE kernel.
Arnd
next prev parent reply other threads:[~2016-07-13 19:57 UTC|newest]
Thread overview: 265+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-07-12 1:41 [RFC 0/3] extend kexec_file_load system call AKASHI Takahiro
2016-07-12 1:41 ` AKASHI Takahiro
2016-07-12 1:41 ` AKASHI Takahiro
2016-07-12 1:41 ` [RFC 1/3] syscall: add kexec_file_load to generic unistd.h AKASHI Takahiro
2016-07-12 1:41 ` AKASHI Takahiro
2016-07-12 1:41 ` AKASHI Takahiro
2016-07-12 1:42 ` [RFC 2/3] kexec: add dtb info to struct kimage AKASHI Takahiro
2016-07-12 1:42 ` AKASHI Takahiro
2016-07-12 1:42 ` AKASHI Takahiro
2016-07-12 1:42 ` [RFC 3/3] kexec: extend kexec_file_load system call AKASHI Takahiro
2016-07-12 1:42 ` AKASHI Takahiro
2016-07-12 1:42 ` AKASHI Takahiro
2016-07-15 13:09 ` Vivek Goyal
2016-07-15 13:09 ` Vivek Goyal
2016-07-15 13:09 ` Vivek Goyal
2016-07-15 13:19 ` Mark Rutland
2016-07-15 13:19 ` Mark Rutland
2016-07-15 13:19 ` Mark Rutland
2016-07-18 2:30 ` Dave Young
2016-07-18 2:30 ` Dave Young
2016-07-18 2:30 ` Dave Young
2016-07-18 10:07 ` Mark Rutland
2016-07-18 10:07 ` Mark Rutland
2016-07-18 10:07 ` Mark Rutland
2016-07-19 0:55 ` Dave Young
2016-07-19 0:55 ` Dave Young
2016-07-19 0:55 ` Dave Young
2016-07-19 10:52 ` Mark Rutland
2016-07-19 10:52 ` Mark Rutland
2016-07-19 10:52 ` Mark Rutland
2016-07-19 12:24 ` Vivek Goyal
2016-07-19 12:24 ` Vivek Goyal
2016-07-19 12:24 ` Vivek Goyal
2016-07-19 12:47 ` Mark Rutland
2016-07-19 12:47 ` Mark Rutland
2016-07-19 12:47 ` Mark Rutland
2016-07-19 13:26 ` Vivek Goyal
2016-07-19 13:26 ` Vivek Goyal
2016-07-19 13:26 ` Vivek Goyal
2016-07-20 11:41 ` David Laight
2016-07-20 11:41 ` David Laight
2016-07-20 11:41 ` David Laight
2016-07-20 11:41 ` David Laight
2016-07-21 9:21 ` Russell King - ARM Linux
2016-07-21 9:21 ` Russell King - ARM Linux
2016-07-21 9:21 ` Russell King - ARM Linux
2016-07-18 2:33 ` Dave Young
2016-07-18 2:33 ` Dave Young
2016-07-18 2:33 ` Dave Young
2016-07-27 0:24 ` [PATCH v2 " Thiago Jung Bauermann
2016-07-27 0:24 ` Thiago Jung Bauermann
2016-07-27 0:24 ` Thiago Jung Bauermann
2016-08-05 20:46 ` Thiago Jung Bauermann
2016-08-05 20:46 ` Thiago Jung Bauermann
2016-08-05 20:46 ` Thiago Jung Bauermann
2016-07-12 13:25 ` [RFC 0/3] " Eric W. Biederman
2016-07-12 13:25 ` Eric W. Biederman
2016-07-12 13:25 ` Eric W. Biederman
2016-07-12 13:58 ` Thiago Jung Bauermann
2016-07-12 13:58 ` Thiago Jung Bauermann
2016-07-12 13:58 ` Thiago Jung Bauermann
2016-07-12 14:02 ` Vivek Goyal
2016-07-12 14:02 ` Vivek Goyal
2016-07-12 14:02 ` Vivek Goyal
2016-07-12 23:45 ` Stewart Smith
2016-07-12 23:45 ` Stewart Smith
2016-07-12 23:45 ` Stewart Smith
2016-07-13 13:27 ` Vivek Goyal
2016-07-13 13:27 ` Vivek Goyal
2016-07-13 13:27 ` Vivek Goyal
2016-07-12 14:02 ` Arnd Bergmann
2016-07-12 14:02 ` Arnd Bergmann
2016-07-12 14:02 ` Arnd Bergmann
2016-07-12 14:18 ` Vivek Goyal
2016-07-12 14:18 ` Vivek Goyal
2016-07-12 14:18 ` Vivek Goyal
2016-07-12 14:24 ` Arnd Bergmann
2016-07-12 14:24 ` Arnd Bergmann
2016-07-12 14:24 ` Arnd Bergmann
2016-07-12 14:50 ` Mark Rutland
2016-07-12 14:50 ` Mark Rutland
2016-07-12 14:50 ` Mark Rutland
2016-07-13 2:36 ` Dave Young
2016-07-13 2:36 ` Dave Young
2016-07-13 2:36 ` Dave Young
2016-07-13 8:01 ` Arnd Bergmann
2016-07-13 8:01 ` Arnd Bergmann
2016-07-13 8:01 ` Arnd Bergmann
2016-07-13 8:23 ` Stewart Smith
2016-07-13 8:23 ` Stewart Smith
2016-07-13 8:23 ` Stewart Smith
2016-07-13 9:41 ` Mark Rutland
2016-07-13 9:41 ` Mark Rutland
2016-07-13 9:41 ` Mark Rutland
2016-07-13 13:13 ` Arnd Bergmann
2016-07-13 13:13 ` Arnd Bergmann
2016-07-13 13:13 ` Arnd Bergmann
2016-07-13 18:45 ` Thiago Jung Bauermann
2016-07-13 18:45 ` Thiago Jung Bauermann
2016-07-13 18:45 ` Thiago Jung Bauermann
2016-07-13 19:59 ` Arnd Bergmann
2016-07-13 19:59 ` Arnd Bergmann
2016-07-13 19:59 ` Arnd Bergmann
2016-07-14 2:18 ` Thiago Jung Bauermann
2016-07-14 2:18 ` Thiago Jung Bauermann
2016-07-14 2:18 ` Thiago Jung Bauermann
2016-07-14 8:29 ` Arnd Bergmann
2016-07-14 8:29 ` Arnd Bergmann
2016-07-14 8:29 ` Arnd Bergmann
2016-07-15 1:44 ` Thiago Jung Bauermann
2016-07-15 1:44 ` Thiago Jung Bauermann
2016-07-15 1:44 ` Thiago Jung Bauermann
2016-07-15 7:31 ` Arnd Bergmann
2016-07-15 7:31 ` Arnd Bergmann
2016-07-15 7:31 ` Arnd Bergmann
2016-07-15 13:26 ` Vivek Goyal
2016-07-15 13:26 ` Vivek Goyal
2016-07-15 13:26 ` Vivek Goyal
2016-07-15 13:33 ` Mark Rutland
2016-07-15 13:33 ` Mark Rutland
2016-07-15 13:33 ` Mark Rutland
2016-07-15 15:29 ` Thiago Jung Bauermann
2016-07-15 15:29 ` Thiago Jung Bauermann
2016-07-15 15:29 ` Thiago Jung Bauermann
2016-07-15 15:47 ` Mark Rutland
2016-07-15 15:47 ` Mark Rutland
2016-07-15 15:47 ` Mark Rutland
2016-07-15 13:42 ` Russell King - ARM Linux
2016-07-15 13:42 ` Russell King - ARM Linux
2016-07-15 13:42 ` Russell King - ARM Linux
2016-07-15 20:26 ` Arnd Bergmann
2016-07-15 20:26 ` Arnd Bergmann
2016-07-15 20:26 ` Arnd Bergmann
2016-07-15 21:03 ` Thiago Jung Bauermann
2016-07-15 21:03 ` Thiago Jung Bauermann
2016-07-15 21:03 ` Thiago Jung Bauermann
2016-07-22 0:09 ` Thiago Jung Bauermann
2016-07-22 0:09 ` Thiago Jung Bauermann
2016-07-22 0:09 ` Thiago Jung Bauermann
2016-07-22 0:53 ` Jeremy Kerr
2016-07-22 0:53 ` Jeremy Kerr
2016-07-22 0:53 ` Jeremy Kerr
2016-07-22 2:54 ` Michael Ellerman
2016-07-22 2:54 ` Michael Ellerman
2016-07-22 2:54 ` Michael Ellerman
2016-07-22 20:41 ` Thiago Jung Bauermann
2016-07-22 20:41 ` Thiago Jung Bauermann
2016-07-22 20:41 ` Thiago Jung Bauermann
2016-07-15 8:49 ` Russell King - ARM Linux
2016-07-15 8:49 ` Russell King - ARM Linux
2016-07-15 8:49 ` Russell King - ARM Linux
2016-07-15 13:03 ` Vivek Goyal
2016-07-15 13:03 ` Vivek Goyal
2016-07-15 13:03 ` Vivek Goyal
2016-07-13 9:34 ` Mark Rutland
2016-07-13 9:34 ` Mark Rutland
2016-07-13 9:34 ` Mark Rutland
2016-07-13 17:38 ` AKASHI Takahiro
2016-07-13 17:38 ` AKASHI Takahiro
2016-07-13 17:38 ` AKASHI Takahiro
2016-07-13 17:58 ` Mark Rutland
2016-07-13 17:58 ` Mark Rutland
2016-07-13 17:58 ` Mark Rutland
2016-07-13 19:57 ` Arnd Bergmann [this message]
2016-07-13 19:57 ` Arnd Bergmann
2016-07-13 19:57 ` Arnd Bergmann
2016-07-14 12:42 ` Mark Rutland
2016-07-14 12:42 ` Mark Rutland
2016-07-14 12:42 ` Mark Rutland
2016-07-14 1:54 ` Dave Young
2016-07-14 1:54 ` Dave Young
2016-07-14 1:54 ` Dave Young
2016-07-14 1:50 ` Dave Young
2016-07-14 1:50 ` Dave Young
2016-07-14 1:50 ` Dave Young
2016-07-12 16:25 ` Thiago Jung Bauermann
2016-07-12 16:25 ` Thiago Jung Bauermann
2016-07-12 16:25 ` Thiago Jung Bauermann
2016-07-12 20:58 ` Petr Tesarik
2016-07-12 20:58 ` Petr Tesarik
2016-07-12 20:58 ` Petr Tesarik
2016-07-12 21:22 ` Eric W. Biederman
2016-07-12 21:22 ` Eric W. Biederman
2016-07-12 21:22 ` Eric W. Biederman
2016-07-12 21:36 ` Eric W. Biederman
2016-07-12 21:36 ` Eric W. Biederman
2016-07-12 21:36 ` Eric W. Biederman
2016-07-12 21:53 ` Petr Tesarik
2016-07-12 21:53 ` Petr Tesarik
2016-07-12 21:53 ` Petr Tesarik
2016-07-12 22:18 ` Russell King - ARM Linux
2016-07-12 22:18 ` Russell King - ARM Linux
2016-07-12 22:18 ` Russell King - ARM Linux
2016-07-13 4:59 ` Stewart Smith
2016-07-13 4:59 ` Stewart Smith
2016-07-13 4:59 ` Stewart Smith
2016-07-13 7:36 ` Russell King - ARM Linux
2016-07-13 7:36 ` Russell King - ARM Linux
2016-07-13 7:36 ` Russell King - ARM Linux
2016-07-13 7:47 ` Ard Biesheuvel
2016-07-13 7:47 ` Ard Biesheuvel
2016-07-13 7:47 ` Ard Biesheuvel
2016-07-13 8:09 ` Russell King - ARM Linux
2016-07-13 8:09 ` Russell King - ARM Linux
2016-07-13 8:09 ` Russell King - ARM Linux
2016-07-13 8:20 ` Stewart Smith
2016-07-13 8:20 ` Stewart Smith
2016-07-13 8:20 ` Stewart Smith
2016-07-13 7:55 ` Stewart Smith
2016-07-13 7:55 ` Stewart Smith
2016-07-13 7:55 ` Stewart Smith
2016-07-13 8:26 ` Russell King - ARM Linux
2016-07-13 8:26 ` Russell King - ARM Linux
2016-07-13 8:26 ` Russell King - ARM Linux
2016-07-13 8:36 ` Dave Young
2016-07-13 8:36 ` Dave Young
2016-07-13 8:36 ` Dave Young
2016-07-13 8:57 ` Petr Tesarik
2016-07-13 8:57 ` Petr Tesarik
2016-07-13 8:57 ` Petr Tesarik
2016-07-13 13:03 ` Vivek Goyal
2016-07-13 13:03 ` Vivek Goyal
2016-07-13 13:03 ` Vivek Goyal
2016-07-13 17:40 ` Russell King - ARM Linux
2016-07-13 17:40 ` Russell King - ARM Linux
2016-07-13 17:40 ` Russell King - ARM Linux
2016-07-13 18:22 ` Vivek Goyal
2016-07-13 18:22 ` Vivek Goyal
2016-07-13 18:22 ` Vivek Goyal
2016-07-18 12:46 ` Balbir Singh
2016-07-18 12:46 ` Balbir Singh
2016-07-18 12:46 ` Balbir Singh
2016-07-18 13:26 ` Vivek Goyal
2016-07-18 13:26 ` Vivek Goyal
2016-07-18 13:26 ` Vivek Goyal
2016-07-18 13:38 ` Vivek Goyal
2016-07-18 13:38 ` Vivek Goyal
2016-07-18 13:38 ` Vivek Goyal
2016-07-20 3:45 ` Balbir Singh
2016-07-20 3:45 ` Balbir Singh
2016-07-20 3:45 ` Balbir Singh
2016-07-20 8:35 ` Russell King - ARM Linux
2016-07-20 8:35 ` Russell King - ARM Linux
2016-07-20 8:35 ` Russell King - ARM Linux
2016-07-20 10:47 ` Michael Ellerman
2016-07-20 10:47 ` Michael Ellerman
2016-07-20 10:47 ` Michael Ellerman
2016-07-20 11:12 ` Arnd Bergmann
2016-07-20 11:12 ` Arnd Bergmann
2016-07-20 11:12 ` Arnd Bergmann
2016-07-20 15:50 ` Thiago Jung Bauermann
2016-07-20 15:50 ` Thiago Jung Bauermann
2016-07-20 15:50 ` Thiago Jung Bauermann
2016-07-20 12:46 ` Vivek Goyal
2016-07-20 12:46 ` Vivek Goyal
2016-07-20 12:46 ` Vivek Goyal
2016-07-20 12:27 ` Vivek Goyal
2016-07-20 12:27 ` Vivek Goyal
2016-07-20 12:27 ` Vivek Goyal
2016-07-12 23:41 ` Stewart Smith
2016-07-12 23:41 ` Stewart Smith
2016-07-12 23:41 ` Stewart Smith
2016-07-13 13:25 ` Vivek Goyal
2016-07-13 13:25 ` Vivek Goyal
2016-07-13 13:25 ` Vivek Goyal
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