[LLVMdev] LLVM JIT on a Baremetal x86 Machine !!!

[James Molloy]

Hi Mian,

Looking at the runlog, everything seems fine until LLVM attempts to use lseek() on a file.

You see the PANIC because Horizon hasn't implemented lseek yet.

Obviously the version of GlibC I was using does not use lseek in that circumstance, but yours does. You just need to implement lseek :)

Cheers,

James

-----Original Message-----
From: Mian M. Hamayun [mailto:mian-muhammad.hamayun at imag.fr]
Sent: 03 November 2011 15:59
To: James Molloy
Cc: llvmdev at cs.uiuc.edu
Subject: Re: [LLVMdev] LLVM JIT on a Baremetal x86 Machine !!!

Hello James,

I hope I will not be disturbing you too much. As I mentioned earlier, I
am interested in unhosted (baremetal) x86 environment for LLVM JIT.
Let me come to the point straight.

I have set the KERNEL_HBC as:
set(KERNEL_HBC
"/altamaha/home3/hamayun/workspace/horizon/code-samples/hello_world.hbc")

And Compiled the Horizon Sources. Compilation works fine and it creates
the cd.img as you described on:
http://www.quokforge.org/projects/horizon/wiki/Building

See the attached "Horizon_Build.Log" file for more details.

Now when I load this 'image' using qemu; It gives me the following error:
horizon: PANIC: syscall 0x8 (lseek) @ 0xc0f530

See the attached "Horizon_Qemu_Run.log" file for more details.

I guess I am not setting the KERNEL_HBC variable properly.
Could you give me an idea of whats going wrong here ?

Thanks a lot,
Hamayun


On 10/28/2011 02:46 PM, Mian M. Hamayun wrote:
> Hi James,
>
> Thanks A lot. I have downloaded the source code and I am currently
> looking into it.
> I will get back to you if I need some clarifications.
>
> Thanks Again,
> --
> Hamayun
>
> On 10/26/2011 03:20 PM, James Molloy wrote:
>> Hi Mian,
>>
>> I have actually done this. I wrote a safe bytecode which compiles down to
>> LLVM IR, and had baremetal applications running using it.
>>
>> Code here:
>> http://www.quokforge.org/projects/horizon/repository/revisions/master/show/h
>>
>> orizon/Baremetal
>>
>> My method was to compile for hosted linux, then modify the resulting
>> code to
>> run baremetal. For me, this involved rewriting "syscall" instructions to
>> "int $X" as everything was running in supervisor mode and "syscall" only
>> works from user mode.
>>
>> Apart from that there's just a load of stubs to implement. Pretty easy
>> really.
>>
>> Cheers,
>>
>> James
>>
>>
>> -----Original Message-----
>> From: llvmdev-bounces at cs.uiuc.edu [mailto:llvmdev-bounces at cs.uiuc.edu] On
>> Behalf Of Mian M. Hamayun
>> Sent: 26 October 2011 14:12
>> To: llvmdev at cs.uiuc.edu
>> Subject: [LLVMdev] LLVM JIT on a Baremetal x86 Machine !!!
>>
>> Dear All,
>>
>> I have tested a few examples of LLVM-JIT Framework on Linux x86 Machine.
>> So generating functions on the fly and then executing them is OK on
>> linux i.e. i686-pc-linux-gnu
>>
>> My question is:
>>
>> Can we use the LLVM-JIT on a baremetal x86 machine ? Actually my target
>> is a virtual machine, and I need some dynamic code generation support. I
>> intend to use LLVM-JIT (if possible) for this purpose.
>>
>> Furthermore if it is possible, then how much effort would be required ?
>> And where should I start looking for doing this kind of port.
>>
>> Thanks for your help.
>>
>> --
>> Hamayun
>> Grenoble, France.
>>
>>
>>
>
>

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