KEXEC on ARM Cortex-A15 versatile express V2P

KEXEC on ARM Cortex-A15 versatile express V2P

[Naresh Bhat]

Hi Daniel,

Thanks for the suggestions.  I really appreciate your help.

I have tried the following in my below setup

My setup:
kexec-tools - latest GIT tree with
http://lists.infradead.org/pipermail/kexec/2012-December/007526.html
patch
Kernel version -   3.4.22
Hardware target -  V2P-CA15_A7 Cortex A15 (ARM Versatile Express)

That could be just that the new kernel is missing its bootargs cmdline
with the appropriate console= tag. How are you booting the first
kernel?

The first kernel command line console=tty0 console=ttyAMA0,38400n8
root=/dev/mmcblk0p1 rootwait ro mmci.fmax=6000000

Does you bootloader add a /chosen tag?

I did't understand what you are asking here .  can you please
elaborate little more ?

Some suggestions:

1. Add a static CMDLINE to the second kernel, so it doesn't rely on
that information being passed from the first on.

root@arm-cortex-a15:~#  kexec -l uImage --dtb=vexpress.dtb
--command-line="console=tty0 console=ttyAMA0,38400n8
root=/dev/mmcblk0p1 rootwait ro mmci.fmax=6000000"
root@arm-cortex-a15:~# kexec -e
Starting new kernel
Uncompressing Linux...

2. Try running kexec without the --dtb option. kexec will then walk
/proc/device-tree and build up one dynamically (CONFIG_PROC_DEVICETREE
is needed for that).
I have enabled the CONFIG_PROC_DEVICETREE option in my kernel and I
have tried without using --dtb option

root@arm-cortex-a15:~#  kexec -l uImage --dtb=vexpress.dtb
--command-line="console=tty0 console=ttyAMA0,38400n8
root=/dev/mmcblk0p1 rootwait ro mmci.fmax=6000000"
Modified cmdline:console=tty0 console=ttyAMA0,38400n8
root=/dev/mmcblk0p1 rootwait ro mmci.fmax=6000000
Unable to find /proc/device-tree//chosen/linux,stdout-path, printing
from purgatory is diabled
root@arm-cortex-a15:~#
root@arm-cortex-a15:~# kexec -e
Starting new kernel
Uncompressing Linux...

3. Try passing --command-line to kexec. Note that this won't work
together with --dtb, as there's currently no code that adds the
cmdline to a dtb binary blob. But with two patches I recently
submitted, it works with the dynamic /proc/device-tree parsing mode.

How can I overcome from the above warning  "Unable to find
/proc/device-tree//chosen/linux,stdout-path, printing from purgatory
is diabled"

4. In case you have LEDs connected to GPIOs on your board, configure
them to the heartbeat trigger mode. If that works, you know that the
kernel is actually booting, but just not showing anything on the
console.
I will open the box on Monday and confirm the same.

5. If 4) fails, try to toggle the GPIOs very early in the boot
process, as some sort of interface to trace the control flow, even
without a JTAG.
I will try it on Monday.  BTW I do not have any JTAG.

6. In case you have CONFIG_THUMB2_KERNEL set, switch it off. I had no
luck yet booting into a kernel that was compiled in Thumb-2 mode.

By default CONFIG_THUMB2_KERNEL is desabled in my kernel


Please, provide your inputs/suggestions so that I can overcome from this issue.
Thanks and Regards
-Naresh Bhat

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Re: KEXEC on ARM Cortex-A15 versatile express V2P

[Daniel Mack]

Hi,

On 14.12.2012 18:33, Naresh Bhat wrote:
> Thanks for the suggestions.  I really appreciate your help.
> 
> I have tried the following in my below setup

Your should really fix your mailer. The way you quote makes it
impossible to see which lines you added.

> My setup:
> kexec-tools - latest GIT tree with
> http://lists.infradead.org/pipermail/kexec/2012-December/007526.html
> patch
> Kernel version -   3.4.22

Why are you running a kernel from the middle ages?

> Hardware target -  V2P-CA15_A7 Cortex A15 (ARM Versatile Express)
> 
> That could be just that the new kernel is missing its bootargs cmdline
> with the appropriate console= tag. How are you booting the first
> kernel?
> 
> The first kernel command line console=tty0 console=ttyAMA0,38400n8
> root=/dev/mmcblk0p1 rootwait ro mmci.fmax=6000000
> 
> Does you bootloader add a /chosen tag?
> 
> I did't understand what you are asking here .  can you please
> elaborate little more ?

Bootloaders have two ways of passing the command line to the kernel. The
traditional way is to stuff it into a a linked list of boot parameters
(ATAGs), the other is to fill the /chosen/bootargs property in the
device tree and then pass the entire tree.

> Some suggestions:
> 
> 1. Add a static CMDLINE to the second kernel, so it doesn't rely on
> that information being passed from the first on.
> 
> root@arm-cortex-a15:~#  kexec -l uImage --dtb=vexpress.dtb
> --command-line="console=tty0 console=ttyAMA0,38400n8
> root=/dev/mmcblk0p1 rootwait ro mmci.fmax=6000000"
> root@arm-cortex-a15:~# kexec -e
> Starting new kernel
> Uncompressing Linux...

If that doesn't work, your problem is not related to any cmdline issue,
and I might have midlead you here.

Please try a newer kernel and see if that helps. The kernels I was using
with kexec recently were 3.7-rcX.


HTH,
Daniel


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Re: KEXEC on ARM Cortex-A15 versatile express V2P

[Daniel Mack]

On 14.12.2012 21:58, Daniel Mack wrote:
> Hi,
> 
> On 14.12.2012 18:33, Naresh Bhat wrote:
>> Thanks for the suggestions.  I really appreciate your help.
>>
>> I have tried the following in my below setup
> 
> Your should really fix your mailer. The way you quote makes it
> impossible to see which lines you added.
> 
>> My setup:
>> kexec-tools - latest GIT tree with
>> http://lists.infradead.org/pipermail/kexec/2012-December/007526.html
>> patch
>> Kernel version -   3.4.22
> 
> Why are you running a kernel from the middle ages?
> 
>> Hardware target -  V2P-CA15_A7 Cortex A15 (ARM Versatile Express)
>>
>> That could be just that the new kernel is missing its bootargs cmdline
>> with the appropriate console= tag. How are you booting the first
>> kernel?
>>
>> The first kernel command line console=tty0 console=ttyAMA0,38400n8
>> root=/dev/mmcblk0p1 rootwait ro mmci.fmax=6000000
>>
>> Does you bootloader add a /chosen tag?
>>
>> I did't understand what you are asking here .  can you please
>> elaborate little more ?
> 
> Bootloaders have two ways of passing the command line to the kernel. The
> traditional way is to stuff it into a a linked list of boot parameters
> (ATAGs), the other is to fill the /chosen/bootargs property in the
> device tree and then pass the entire tree.
> 
>> Some suggestions:
>>
>> 1. Add a static CMDLINE to the second kernel, so it doesn't rely on
>> that information being passed from the first on.
>>
>> root@arm-cortex-a15:~#  kexec -l uImage --dtb=vexpress.dtb
>> --command-line="console=tty0 console=ttyAMA0,38400n8
>> root=/dev/mmcblk0p1 rootwait ro mmci.fmax=6000000"
>> root@arm-cortex-a15:~# kexec -e
>> Starting new kernel
>> Uncompressing Linux...
> 
> If that doesn't work, your problem is not related to any cmdline issue,
> and I might have midlead you here.
> 
> Please try a newer kernel and see if that helps. The kernels I was using
> with kexec recently were 3.7-rcX.

But just to be clear: it should of course work with the version you're
running. So that might not be the reason.

And one more thing that might be a hint: check which parts of the
hardware are actually running. We experienced some weird lockups during
kexec if audio was streaming on our device, but in such cases, we didn't
see the "Uncompressing Linux..." output either.

Not sure how to help you here really.


Daniel


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Re: KEXEC on ARM Cortex-A15 versatile express V2P

[Naresh Bhat]

Hi Daniel Mack,

I have tried with the latest kernel and getting the below error

root@arm-cortex-a15:~/3.7-kernel#
3.7-kernel# kexec -f zImage --dtb=v.dtb --command-line="console=ttyAMA0,38400n8"
FDT: Error setting /chosen/bootargs property.
Cannot load zImage
root@arm-cortex-a15:~/3.7-kernel#

I will appreciate your inputs

Thanks and Regards
-Naresh Bhat

On Sat, Dec 15, 2012 at 2:34 AM, Daniel Mack <zonque@gmail.com> wrote:
> On 14.12.2012 21:58, Daniel Mack wrote:
>> Hi,
>>
>> On 14.12.2012 18:33, Naresh Bhat wrote:
>>> Thanks for the suggestions.  I really appreciate your help.
>>>
>>> I have tried the following in my below setup
>>
>> Your should really fix your mailer. The way you quote makes it
>> impossible to see which lines you added.
>>
>>> My setup:
>>> kexec-tools - latest GIT tree with
>>> http://lists.infradead.org/pipermail/kexec/2012-December/007526.html
>>> patch
>>> Kernel version -   3.4.22
>>
>> Why are you running a kernel from the middle ages?
>>
>>> Hardware target -  V2P-CA15_A7 Cortex A15 (ARM Versatile Express)
>>>
>>> That could be just that the new kernel is missing its bootargs cmdline
>>> with the appropriate console= tag. How are you booting the first
>>> kernel?
>>>
>>> The first kernel command line console=tty0 console=ttyAMA0,38400n8
>>> root=/dev/mmcblk0p1 rootwait ro mmci.fmax=6000000
>>>
>>> Does you bootloader add a /chosen tag?
>>>
>>> I did't understand what you are asking here .  can you please
>>> elaborate little more ?
>>
>> Bootloaders have two ways of passing the command line to the kernel. The
>> traditional way is to stuff it into a a linked list of boot parameters
>> (ATAGs), the other is to fill the /chosen/bootargs property in the
>> device tree and then pass the entire tree.
>>
>>> Some suggestions:
>>>
>>> 1. Add a static CMDLINE to the second kernel, so it doesn't rely on
>>> that information being passed from the first on.
>>>
>>> root@arm-cortex-a15:~#  kexec -l uImage --dtb=vexpress.dtb
>>> --command-line="console=tty0 console=ttyAMA0,38400n8
>>> root=/dev/mmcblk0p1 rootwait ro mmci.fmax=6000000"
>>> root@arm-cortex-a15:~# kexec -e
>>> Starting new kernel
>>> Uncompressing Linux...
>>
>> If that doesn't work, your problem is not related to any cmdline issue,
>> and I might have midlead you here.
>>
>> Please try a newer kernel and see if that helps. The kernels I was using
>> with kexec recently were 3.7-rcX.
>
> But just to be clear: it should of course work with the version you're
> running. So that might not be the reason.
>
> And one more thing that might be a hint: check which parts of the
> hardware are actually running. We experienced some weird lockups during
> kexec if audio was streaming on our device, but in such cases, we didn't
> see the "Uncompressing Linux..." output either.
>
> Not sure how to help you here really.
>
>
> Daniel
>



-- 
"For things to change, we must change"
-Naresh Bhat

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Re: KEXEC on ARM Cortex-A15 versatile express V2P

[Naresh Bhat]

Hi Daniel,

I have also tried enabling the DEVICETREE option but no luck on latest
3.7 kernel.

root@arm-cortex-a15:~# kexec -l zImage --command-line="console=ttyAMA0,38400n8"
Modified cmdline:console=ttyAMA0,38400n8 root=/dev/nfs
Unable to find /proc/device-tree//chosen/linux,stdout-path, printing
from purgatory is diabled
root@arm-cortex-a15:~# kexec -e
Uncompressing Linux...

I have a question is it required to enable "LIBFDT" option ?  I have
used vexpress_defconfig file in which it is not enabled.

Symbol: LIBFDT [=n]
Type  : boolean


Thanks and Regards
-Naresh Bhat

On Wed, Jan 2, 2013 at 7:26 PM, Naresh Bhat <nareshgbhat@gmail.com> wrote:
> Hi Daniel Mack,
>
> I have tried with the latest kernel and getting the below error
>
> root@arm-cortex-a15:~/3.7-kernel#
> 3.7-kernel# kexec -f zImage --dtb=v.dtb --command-line="console=ttyAMA0,38400n8"
> FDT: Error setting /chosen/bootargs property.
> Cannot load zImage
> root@arm-cortex-a15:~/3.7-kernel#
>
> I will appreciate your inputs
>
> Thanks and Regards
> -Naresh Bhat
>
> On Sat, Dec 15, 2012 at 2:34 AM, Daniel Mack <zonque@gmail.com> wrote:
>> On 14.12.2012 21:58, Daniel Mack wrote:
>>> Hi,
>>>
>>> On 14.12.2012 18:33, Naresh Bhat wrote:
>>>> Thanks for the suggestions.  I really appreciate your help.
>>>>
>>>> I have tried the following in my below setup
>>>
>>> Your should really fix your mailer. The way you quote makes it
>>> impossible to see which lines you added.
>>>
>>>> My setup:
>>>> kexec-tools - latest GIT tree with
>>>> http://lists.infradead.org/pipermail/kexec/2012-December/007526.html
>>>> patch
>>>> Kernel version -   3.4.22
>>>
>>> Why are you running a kernel from the middle ages?
>>>
>>>> Hardware target -  V2P-CA15_A7 Cortex A15 (ARM Versatile Express)
>>>>
>>>> That could be just that the new kernel is missing its bootargs cmdline
>>>> with the appropriate console= tag. How are you booting the first
>>>> kernel?
>>>>
>>>> The first kernel command line console=tty0 console=ttyAMA0,38400n8
>>>> root=/dev/mmcblk0p1 rootwait ro mmci.fmax=6000000
>>>>
>>>> Does you bootloader add a /chosen tag?
>>>>
>>>> I did't understand what you are asking here .  can you please
>>>> elaborate little more ?
>>>
>>> Bootloaders have two ways of passing the command line to the kernel. The
>>> traditional way is to stuff it into a a linked list of boot parameters
>>> (ATAGs), the other is to fill the /chosen/bootargs property in the
>>> device tree and then pass the entire tree.
>>>
>>>> Some suggestions:
>>>>
>>>> 1. Add a static CMDLINE to the second kernel, so it doesn't rely on
>>>> that information being passed from the first on.
>>>>
>>>> root@arm-cortex-a15:~#  kexec -l uImage --dtb=vexpress.dtb
>>>> --command-line="console=tty0 console=ttyAMA0,38400n8
>>>> root=/dev/mmcblk0p1 rootwait ro mmci.fmax=6000000"
>>>> root@arm-cortex-a15:~# kexec -e
>>>> Starting new kernel
>>>> Uncompressing Linux...
>>>
>>> If that doesn't work, your problem is not related to any cmdline issue,
>>> and I might have midlead you here.
>>>
>>> Please try a newer kernel and see if that helps. The kernels I was using
>>> with kexec recently were 3.7-rcX.
>>
>> But just to be clear: it should of course work with the version you're
>> running. So that might not be the reason.
>>
>> And one more thing that might be a hint: check which parts of the
>> hardware are actually running. We experienced some weird lockups during
>> kexec if audio was streaming on our device, but in such cases, we didn't
>> see the "Uncompressing Linux..." output either.
>>
>> Not sure how to help you here really.
>>
>>
>> Daniel
>>
>
>
>
> --
> "For things to change, we must change"
> -Naresh Bhat



-- 
"For things to change, we must change"
-Naresh Bhat

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