[Qemu-devel] Run program without kernel. Possible? (part 2)

[Qemu-devel] Run program without kernel. Possible? (part 2)

[Luis Pureza]

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Hi,

First, let me apologise if this isn't the right place for asking this.

Yesterday I posted this thread (
http://qemu.dad-answers.com/viewtopic.php?t=1804) on the general help forum,
but it seems I got no answer. This is kinda urgent and I'd really appreciate
any help.

Again, sorry for being a stubborn

Thanks,

Luís Pureza

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Re: [Qemu-devel] Run program without kernel. Possible? (part 2)

[Johannes Schindelin]

Hi,

Yes. To a certain extent: If you run x86 linux, and you want to execute a 
program for PPC linux, you can use the usermode emulation (-user).

Unfortunately, this is only possible if you run Linux _and_ the program is 
for Linux (on another CPU).

If you want to do this for Darwin, you might be lucky with the usermode 
emulation of darwine (which is not yet merged with mainstream QEmu, 
unfortunately).

Maybe you want to ask in a more precise fashion what you want to achieve?

Ciao,
Dscho

Re: [Qemu-devel] Run program without kernel. Possible? (part 2)

[Marco Matthies]

[sorry for posting this back to the list, but i'm too lazy to register 
for the forum]

Luis Pureza wrote:
 > Is it possible to run some program with qemu without a kernel attached?
 >
 > I'm involved in a project to create an emulator for the leon2 
processor (which is sparc-like). In order to estimate the kind of 
performance gains we can achieve using dynamic transalation, I'd like to 
run some small benchmarks without the overhead of the operative system.

If i understand you correctly, you want to try qemu-user. Beware that 
when benchmarking, qemu-user should probably be faster than qemu-system, 
as it doesn't have to emulate the os and hardware.

Marco

Re: [Qemu-devel] Run program without kernel. Possible? (part 2)

[Luis Pureza]

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Hi,

I think you got it right. I compiled a small test program on linux/x86 using
a cross compiler that generates sparc binaries.

Then I tried to emulate it (still on linux/x86) using

$ qemu-sparc -d in_asm program

and it starts emulating but then fails:

Unhandled trap: 0x2
pc: 40002bac  npc: 40002bb0
General Registers:
%g0: 00000000   %g1: 40002bac   %g2: 00000000   %g3: 00000000
%g4: 40002800   %g5: 00000000   %g6: 00000000   %g7: 00000000
Current Register Window:
%o0: 00000000   %o1: 00000000   %o2: 00000000   %o3: 00000000
%o4: 00000000   %o5: 00000000   %o6: b7dbb2a0   %o7: 40002b00
%l0: 00000000   %l1: 00000000   %l2: 00000000   %l3: 00000000
%l4: 00000000   %l5: 00000000   %l6: 00000000   %l7: 00000000
%i0: 00000000   %i1: 00000000   %i2: 00000000   %i3: 00000000
%i4: 00000000   %i5: 00000000   %i6: 00000000   %i7: 00000000

Floating Point Registers:
<All 0>
psr: 0x04000000 -> ---- --- wim: 0x00000001
fsr: 0x00000000

According to the SPARC manual that is an illegal instruction trap. The
log contains:

##########################################################
start    end      size     prot
40000000-40004000 00004000 rwx
b7d76000-b7df6000 00080000 rw-
b7df6000-b7df7000 00001000 ---
start_brk   0x40003adc
end_code    0x400038c4
start_code  0x40000000
end_data    0x400038c4
start_stack 0xb7df52e0
brk         0x40003adc
entry       0x40000000
--------------
IN:
0x40000000:  mov  %g0, %g4
0x40000004:  sethi  %hi(0x40002800), %g4
0x40000008:  jmp  %g4 + 0x2f8   ! 0x40002af8
0x4000000c:  nop

--------------
IN:
0x40002af8:  sethi  %hi(0x40002800), %g1
0x40002afc:  or  %g1, 0x3ac, %g1        ! 0x40002bac
0x40002b00:  call  %g1
0x40002b04:  nop

--------------
IN:
0x40002bac:  rd  %psr, %l3
##########################################################
This last instruction seems to be completely legal, so I don't really
know what's happening...
The source for the program is in attachment.

Thanks for your help.

Luís Pureza

P.S.: By the way, every time I tried qemu-i386 using examples from the
official documentation, it failed with this error:

cannot set up thread-local storage: set_thread_area failed when
setting up thread-local storage

Seems to be something related to my glibc. My problem?



On 7/18/06, Johannes Schindelin <Johannes.Schindelin@gmx.de> wrote:
>
> Hi,
>
> Yes. To a certain extent: If you run x86 linux, and you want to execute a
> program for PPC linux, you can use the usermode emulation (-user).
>
> Unfortunately, this is only possible if you run Linux _and_ the program is
> for Linux (on another CPU).
>
> If you want to do this for Darwin, you might be lucky with the usermode
> emulation of darwine (which is not yet merged with mainstream QEmu,
> unfortunately).
>
> Maybe you want to ask in a more precise fashion what you want to achieve?
>
> Ciao,
> Dscho
>
>
>
> _______________________________________________
> Qemu-devel mailing list
> Qemu-devel@nongnu.org
> http://lists.nongnu.org/mailman/listinfo/qemu-devel
>

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[-- Attachment #2: teste3.c --]
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int main(void)
{
	int i;
	i = 3 + 4;
	return 0;
}

Re: [Qemu-devel] Run program without kernel. Possible? (part 2)

[Blue Swirl]

>IN:
>0x40002bac:  rd  %psr, %l3
>##########################################################
>This last instruction seems to be completely legal, so I don't really
>know what's happening...

User mode emulator does not allow supervisor mode instructions at all. Try 
the system emulator (qemu-system-sparc) instead, or compile your program so 
that the startup code doesn't use any supervisor instructions.

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