[Qemu-devel] HelloWord kernel for qemu-system-aarch64

[Qemu-devel] HelloWord kernel for qemu-system-aarch64

[Semion Prihodko]

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Hi guys,

Need your help. I trying to find a way to compile/link a minimal kernel
which outputs "Hello World" in qemu-system-aarch64. No tutorial found.
There is no problem running the same example in Foundation emulator, but I
need QEMU.

Trying to reuse axf-file in Foundation example:

aarch64-linux-gnu-objcopy -O binary hello.axf kernel.bin
qemu-system-aarch64 -machine virt -cpu cortex-a57 -nographic -smp 1 -m 3G
-kernel kernel.bin

I got:

qemu: fatal: Trying to execute code outside RAM or ROM at 0x0000000000000000

What's wrong here? Can you show me some tutorial how to build minimal
HelloWorld kernel for qemu-system-aarch64 (without need to generate
axf-file)? Thanks in advance.

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Re: [Qemu-devel] HelloWord kernel for qemu-system-aarch64

[Peter Maydell]

On 4 September 2014 11:40, Semion Prihodko <semion.ababo@gmail.com> wrote:
> Hi guys,
>
> Need your help. I trying to find a way to compile/link a minimal kernel
> which outputs "Hello World" in qemu-system-aarch64. No tutorial found. There
> is no problem running the same example in Foundation emulator, but I need
> QEMU.
>
> Trying to reuse axf-file in Foundation example:
>
> aarch64-linux-gnu-objcopy -O binary hello.axf kernel.bin
> qemu-system-aarch64 -machine virt -cpu cortex-a57 -nographic -smp 1 -m 3G
> -kernel kernel.bin
>
> I got:
>
> qemu: fatal: Trying to execute code outside RAM or ROM at 0x0000000000000000

If you use "-kernel" and it's not an ELF file, then we assume it's
a Linux kernel image with the arm64 Linux image header format.
Since in your case this probably isn't true, we're crashing very
early on.

You probably want:
(1) to pass the ELF file directly to QEMU rather than converting
it to a binary
(2) to make sure your image is linked correctly to work with
the "virt" board's memory layout, which is different from that
of the Foundation models

thanks
-- PMM

Re: [Qemu-devel] HelloWord kernel for qemu-system-aarch64

[Semion Prihodko]

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Still don't know how to build/run a simple Hello World kernel on
qemu-system-aarch64?

Guys, this is a very basic thing, please provide concrete steps. Thanks.


2014-09-04 16:29 GMT+03:00 Peter Maydell <peter.maydell@linaro.org>:

> On 4 September 2014 11:40, Semion Prihodko <semion.ababo@gmail.com> wrote:
> > Hi guys,
> >
> > Need your help. I trying to find a way to compile/link a minimal kernel
> > which outputs "Hello World" in qemu-system-aarch64. No tutorial found.
> There
> > is no problem running the same example in Foundation emulator, but I need
> > QEMU.
> >
> > Trying to reuse axf-file in Foundation example:
> >
> > aarch64-linux-gnu-objcopy -O binary hello.axf kernel.bin
> > qemu-system-aarch64 -machine virt -cpu cortex-a57 -nographic -smp 1 -m 3G
> > -kernel kernel.bin
> >
> > I got:
> >
> > qemu: fatal: Trying to execute code outside RAM or ROM at
> 0x0000000000000000
>
> If you use "-kernel" and it's not an ELF file, then we assume it's
> a Linux kernel image with the arm64 Linux image header format.
> Since in your case this probably isn't true, we're crashing very
> early on.
>
> You probably want:
> (1) to pass the ELF file directly to QEMU rather than converting
> it to a binary
> (2) to make sure your image is linked correctly to work with
> the "virt" board's memory layout, which is different from that
> of the Foundation models
>
> thanks
> -- PMM
>

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Re: [Qemu-devel] HelloWord kernel for qemu-system-aarch64

[Peter Maydell]

On 4 September 2014 14:40, Semion Prihodko <semion.ababo@gmail.com> wrote:
> Still don't know how to build/run a simple Hello World kernel on
> qemu-system-aarch64?
>
> Guys, this is a very basic thing, please provide concrete steps. Thanks

It's a non-standard use case. The usual use case is "boot
Linux", which you can find documented here, for instance:
http://www.bennee.com/~alex/blog/2014/05/09/running-linux-in-qemus-aarch64-system-emulation-mode/

If you're trying to boot your own bare-metal image then
you're expected to know what you're doing and be able to
resolve problems to some extent.

thanks
-- PMM

Re: [Qemu-devel] HelloWord kernel for qemu-system-aarch64

[Semion Prihodko]

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Does it mean QEMU emulator is designed to run Linux only? This is not true.

So I ask QEMU developers for help, because they are able to resolve
problems to some extent. Please help me guys. Thanks.


2014-09-04 16:44 GMT+03:00 Peter Maydell <peter.maydell@linaro.org>:

> On 4 September 2014 14:40, Semion Prihodko <semion.ababo@gmail.com> wrote:
> > Still don't know how to build/run a simple Hello World kernel on
> > qemu-system-aarch64?
> >
> > Guys, this is a very basic thing, please provide concrete steps. Thanks
>
> It's a non-standard use case. The usual use case is "boot
> Linux", which you can find documented here, for instance:
>
> http://www.bennee.com/~alex/blog/2014/05/09/running-linux-in-qemus-aarch64-system-emulation-mode/
>
> If you're trying to boot your own bare-metal image then
> you're expected to know what you're doing and be able to
> resolve problems to some extent.
>
> thanks
> -- PMM
>

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Re: [Qemu-devel] HelloWord kernel for qemu-system-aarch64

[Peter Maydell]

On 4 September 2014 14:49, Semion Prihodko <semion.ababo@gmail.com> wrote:
> Does it mean QEMU emulator is designed to run Linux only? This is not true.

No. It means what I said: you can do this, but you're doing
something odd and therefore you can't expect that there
will be documentation holding your hand every step of the
way.

> So I ask QEMU developers for help, because they are able to resolve problems
> to some extent. Please help me guys. Thanks.

I have in fact given you help: I suggested why your current
attempt is crashing and a better approach you should take.

thanks
-- PMM

Re: [Qemu-devel] HelloWord kernel for qemu-system-aarch64

[Christopher Covington]

Hi Semion,

On 09/04/2014 09:40 AM, Semion Prihodko wrote:
> Still don't know how to build/run a simple Hello World kernel on
> qemu-system-aarch64?
> 
> Guys, this is a very basic thing, please provide concrete steps. Thanks.

Here you go. Start at the wget.

http://lists.gnu.org/archive/html/qemu-devel/2014-07/msg03487.html

Angel semihosting isn't implemented upstream so a text hello world won't be
trivial, although given enough time it should be possible to implement Angel
semihosting for A64 in QEMU, implement DCC in QEMU and Newlib/libgloss or
implement PL011 UART or VirtIO-MMIO console in Newlib/libgloss.

Some of the bootloaders and firmwares out there (bootwrapper, ARM trusted
firmware, UEFI/Tianocore) may have examples of using the PL011 UART.

Christopher

-- 
Employee of Qualcomm Innovation Center, Inc.
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum,
hosted by the Linux Foundation.

Re: [Qemu-devel] HelloWord kernel for qemu-system-aarch64

[Semion Prihodko]

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Let's discard semihosting. I have aarch64-linux-gnu-* toolchain and
qemu-system-aarch64 emulator. How can I build a minimal kernel which
outputs Hello World! via serial port and run it on the emulator?


2014-09-04 21:15 GMT+03:00 Christopher Covington <cov@codeaurora.org>:

> Hi Semion,
>
> On 09/04/2014 09:40 AM, Semion Prihodko wrote:
> > Still don't know how to build/run a simple Hello World kernel on
> > qemu-system-aarch64?
> >
> > Guys, this is a very basic thing, please provide concrete steps. Thanks.
>
> Here you go. Start at the wget.
>
> http://lists.gnu.org/archive/html/qemu-devel/2014-07/msg03487.html
>
> Angel semihosting isn't implemented upstream so a text hello world won't be
> trivial, although given enough time it should be possible to implement
> Angel
> semihosting for A64 in QEMU, implement DCC in QEMU and Newlib/libgloss or
> implement PL011 UART or VirtIO-MMIO console in Newlib/libgloss.
>
> Some of the bootloaders and firmwares out there (bootwrapper, ARM trusted
> firmware, UEFI/Tianocore) may have examples of using the PL011 UART.
>
> Christopher
>
> --
> Employee of Qualcomm Innovation Center, Inc.
> Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum,
> hosted by the Linux Foundation.
>

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Re: [Qemu-devel] HelloWord kernel for qemu-system-aarch64

[Claudio Fontana]

On 05.09.2014 16:50, Semion Prihodko wrote:
> Let's discard semihosting. I have aarch64-linux-gnu-* toolchain and
> qemu-system-aarch64 emulator. How can I build a minimal kernel which
> outputs Hello World! via serial port and run it on the emulator?
> 

If you run qemu with the "virt" platform, you can write to the UART at 0x9000000
to get a character out, works very early.

You could check the AArch64 port of the OSv Operating System, has a simple boot loader
you can look at (arch/aarch64/preboot.S and arch/aarch64/boot.S)
and the pl011 device you find in drivers/pl011.cc

https://github.com/cloudius-systems/osv/wiki/AArch64

Good luck,

Claudio

> 
> 2014-09-04 21:15 GMT+03:00 Christopher Covington <cov@codeaurora.org>:
> 
>> Hi Semion,
>>
>> On 09/04/2014 09:40 AM, Semion Prihodko wrote:
>>> Still don't know how to build/run a simple Hello World kernel on
>>> qemu-system-aarch64?
>>>
>>> Guys, this is a very basic thing, please provide concrete steps. Thanks.
>>
>> Here you go. Start at the wget.
>>
>> http://lists.gnu.org/archive/html/qemu-devel/2014-07/msg03487.html
>>
>> Angel semihosting isn't implemented upstream so a text hello world won't be
>> trivial, although given enough time it should be possible to implement
>> Angel
>> semihosting for A64 in QEMU, implement DCC in QEMU and Newlib/libgloss or
>> implement PL011 UART or VirtIO-MMIO console in Newlib/libgloss.
>>
>> Some of the bootloaders and firmwares out there (bootwrapper, ARM trusted
>> firmware, UEFI/Tianocore) may have examples of using the PL011 UART.
>>
>> Christopher
>>
>> --
>> Employee of Qualcomm Innovation Center, Inc.
>> Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum,
>> hosted by the Linux Foundation.
>>

Re: [Qemu-devel] HelloWord kernel for qemu-system-aarch64

[Semion Prihodko]

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This is tricky to deepen in this large code base. It looks strange that
there's no simple concrete tutorial like we have for all other CPU
architectures (e.g. in osdev.org).
05 Сен 2014 г. 19:57 пользователь "Claudio Fontana" <
claudio.fontana@huawei.com> написал:

> On 05.09.2014 16:50, Semion Prihodko wrote:
> > Let's discard semihosting. I have aarch64-linux-gnu-* toolchain and
> > qemu-system-aarch64 emulator. How can I build a minimal kernel which
> > outputs Hello World! via serial port and run it on the emulator?
> >
>
> If you run qemu with the "virt" platform, you can write to the UART at
> 0x9000000
> to get a character out, works very early.
>
> You could check the AArch64 port of the OSv Operating System, has a simple
> boot loader
> you can look at (arch/aarch64/preboot.S and arch/aarch64/boot.S)
> and the pl011 device you find in drivers/pl011.cc
>
> https://github.com/cloudius-systems/osv/wiki/AArch64
>
> Good luck,
>
> Claudio
>
> >
> > 2014-09-04 21:15 GMT+03:00 Christopher Covington <cov@codeaurora.org>:
> >
> >> Hi Semion,
> >>
> >> On 09/04/2014 09:40 AM, Semion Prihodko wrote:
> >>> Still don't know how to build/run a simple Hello World kernel on
> >>> qemu-system-aarch64?
> >>>
> >>> Guys, this is a very basic thing, please provide concrete steps.
> Thanks.
> >>
> >> Here you go. Start at the wget.
> >>
> >> http://lists.gnu.org/archive/html/qemu-devel/2014-07/msg03487.html
> >>
> >> Angel semihosting isn't implemented upstream so a text hello world
> won't be
> >> trivial, although given enough time it should be possible to implement
> >> Angel
> >> semihosting for A64 in QEMU, implement DCC in QEMU and Newlib/libgloss
> or
> >> implement PL011 UART or VirtIO-MMIO console in Newlib/libgloss.
> >>
> >> Some of the bootloaders and firmwares out there (bootwrapper, ARM
> trusted
> >> firmware, UEFI/Tianocore) may have examples of using the PL011 UART.
> >>
> >> Christopher
> >>
> >> --
> >> Employee of Qualcomm Innovation Center, Inc.
> >> Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum,
> >> hosted by the Linux Foundation.
> >>
>
>

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Re: [Qemu-devel] HelloWord kernel for qemu-system-aarch64

[Christopher Covington]

On 09/05/2014 01:52 PM, Semion Prihodko wrote:
> This is tricky to deepen in this large code base. It looks strange that
> there's no simple concrete tutorial like we have for all other CPU
> architectures (e.g. in osdev.org <http://osdev.org>).

AArch64 hasn't really changed the PL011 UART (nor GIC, nor VirtIO-MMIO, nor
semihosting, although maybe DCC a little) as far as I recall. The UART
functions from the following article are probably reusable.

http://wiki.osdev.org/ARM_Integrator-CP_IRQTimerAndPIC

Among other things, AArch64 is pretty new compared to the other architectures
on osdev.org. If you get something going, maybe you can write the tutorial.

Christopher

> 05 Сен 2014 г. 19:57 пользователь "Claudio Fontana"
> <claudio.fontana@huawei.com <mailto:claudio.fontana@huawei.com>> написал:
> 
>     On 05.09.2014 16 <tel:05.09.2014%2016>:50, Semion Prihodko wrote:
>     > Let's discard semihosting. I have aarch64-linux-gnu-* toolchain and
>     > qemu-system-aarch64 emulator. How can I build a minimal kernel which
>     > outputs Hello World! via serial port and run it on the emulator?
>     >
> 
>     If you run qemu with the "virt" platform, you can write to the UART at
>     0x9000000
>     to get a character out, works very early.
> 
>     You could check the AArch64 port of the OSv Operating System, has a simple
>     boot loader
>     you can look at (arch/aarch64/preboot.S and arch/aarch64/boot.S)
>     and the pl011 device you find in drivers/pl011.cc
> 
>     https://github.com/cloudius-systems/osv/wiki/AArch64
> 
>     Good luck,
> 
>     Claudio
> 
>     >
>     > 2014-09-04 21:15 GMT+03:00 Christopher Covington <cov@codeaurora.org
>     <mailto:cov@codeaurora.org>>:
>     >
>     >> Hi Semion,
>     >>
>     >> On 09/04/2014 09:40 AM, Semion Prihodko wrote:
>     >>> Still don't know how to build/run a simple Hello World kernel on
>     >>> qemu-system-aarch64?
>     >>>
>     >>> Guys, this is a very basic thing, please provide concrete steps. Thanks.
>     >>
>     >> Here you go. Start at the wget.
>     >>
>     >> http://lists.gnu.org/archive/html/qemu-devel/2014-07/msg03487.html
>     >>
>     >> Angel semihosting isn't implemented upstream so a text hello world won't be
>     >> trivial, although given enough time it should be possible to implement
>     >> Angel
>     >> semihosting for A64 in QEMU, implement DCC in QEMU and Newlib/libgloss or
>     >> implement PL011 UART or VirtIO-MMIO console in Newlib/libgloss.
>     >>
>     >> Some of the bootloaders and firmwares out there (bootwrapper, ARM trusted
>     >> firmware, UEFI/Tianocore) may have examples of using the PL011 UART.
>     >>
>     >> Christopher
>     >>
>     >> --
>     >> Employee of Qualcomm Innovation Center, Inc.
>     >> Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum,
>     >> hosted by the Linux Foundation.
>     >>
> 


-- 
Employee of Qualcomm Innovation Center, Inc.
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum,
hosted by the Linux Foundation.