Re: [Qemu-devel] qemu-system-arm system support for big endian BE8

[sridhar kulkarni <sridhar_kulk@yahoo.com>]

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Hi,
Floating point exception error was the result of a divide by zero in the application. That is now solved and I was able to progress pretty well with Big Endinan code.Currently QEMU crashes during handling interrupt controller. 
Following the dump that I captured. 
----------------IN: 0xe003b47c: 68e0 ldr r0, [r4, #12]0xe003b47e: b110 cbz r0, 0xe003b486Trace 0x7f1af25f8410 [e003b47c] R00=00000001 R01=0001c200 R02=00000001 R03=c16890e8R04=c16890e8 R05=e003b18c R06=00000080 R07=0000a000R08=ffffffff R09=00000001 R10=0001c200 R11=00000000R12=00000000 R13=c1c3a320 R14=e003b33d R15=e003b47cPSR=20000133 --C- T svc32----------------IN: 0xe003b486: f8d4 b01c ldr.w fp, [r4, #28]0xe003b48a: f44f 5180 mov.w r1, #4096 ; 0x10000xe003b48e: f241 1021 movw r0, #4385 ; 0x11210xe003b492: f8ab 1000 strh.w r1, [fp]0xe003b496: f64f 4100 movw r1, #64512 ; 0xfc000xe003b49a: f2c7 4102 movt r1, #29698 ; 0x74020xe003b49e: 8008 strh r0, [r1, #0]0xe003b4a0: f242 1012 movw r0, #8466 ; 0x21120xe003b4a4: 8048 strh----------------IN: 0x00000194: e121f000 msr CPSR_c, r0Trace 0x7f1af259c000 [00000194] R00=8000039f R01=80000380 R02=770004c8 R03=80000380R04=00000148 R05=00000000 R06=c16890e8 R07=00000001R08=00000001 R09=00000000 R10=00000000 R11=c16746e1R12=00000000 R13=00004b80 R14=00000188 R15=00000194PSR=80000380 N--- A usr26qemu: hardware error: bank number requested for bad CPSR mode value 0x0CPU #0:R00=8000039f R01=80000380 R02=770004c8 R03=80000380R04=00000148 R05=00000000 R06=c16890e8 R07=00000001R08=00000001 R09=00000000 R10=00000000 R11=c16746e1R12=00000000 R13=00004b80 R14=00000188 R15=00000194PSR=80000380 N--- A usr26s00=00000000 s01=00000000 d00=0000000000000000s02=00000000 s03=00000000 d01=0000000000000000s04=00000000 s05=00000000 d02=0000000000000000s06=00000000 s07=00000000 d03=0000000000000000s08=00000000 s09=00000000 d04=0000000000000000s12=00000000 s13=00000000 d06=0000000000000000s14=00000000 s15=00000000 d07=0000000000000000s16=00000000 s17=00000000 d08=0000000000000000s18=00000000 s19=00000000 d09=0000000000000000s20=00000000 s21=00000000 d10=0000000000000000s22=00000000 s23=00000000 d11=0000000000000000s24=00000000 s25=00000000 d12=0000000000000000s26=00000000 s27=00000000 d13=0000000000000000s28=00000000 s29=00000000 d14=0000000000000000s30=00000000 s31=00000000 d15=0000000000000000s32=00000000 s33=00000000 d16=0000000000000000s34=00000000 s35=00000000 d17=0000000000000000s36=00000000 s37=00000000 d18=0000000000000000s38=00000000 s39=00000000 d19=0000000000000000s40=00000000 s41=00000000 d20=0000000000000000s42=00000000 s43=00000000 d21=0000000000000000s44=00000000 s45=00000000 d22=0000000000000000s46=00000000 s47=00000000 d23=0000000000000000s48=00000000 s49=00000000 d24=0000000000000000s50=00000000 s51=00000000 d25=0000000000000000s52=00000000 s53=00000000 d26=0000000000000000s54=00000000 s55=00000000 d27=0000000000000000s56=00000000 s57=00000000 d28=0000000000000000s58=00000000 s59=00000000 d29=0000000000000000s60=00000000 s61=00000000 d30=0000000000000000s62=00000000 s63=00000000 d31=0000000000000000FPSCR: 03000000Aborted (core dumped)

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Please let me know if you have inputs for this crash. Also let me know if you need any further info to help look in to this.
RegardsSridhar　

 


     On Thursday, September 24, 2015 9:47 PM, Peter Crosthwaite <crosthwaitepeter@gmail.com> wrote:
   

 On Thu, Sep 24, 2015 at 3:48 AM, sridhar kulkarni
<sridhar_kulk@yahoo.com> wrote:
> The issue is mostly related to my application under test. When the
> application calls a function the PC is getting set up to a wrong address,
> and then qemu crashes by displaying "floating point exception(core dumped)"
> message.
> I am able to move ahead by resolving the issue.

Was this a QEMU bug or an issue in your program?

But interestingly whenever
> my app crashes it always displays the same "floating point exception"
> message. But I don't see any floating operations at the point code crashes.
> I don't see any dump of the processor registers also. It's always just a one
> line message as I described above.
>

Ok, are you unable to share the binary or source? Alternatively, can
you strip it down to a super-minimal program that replicates just this
one issue? Pasting us a GDB backtrace of the failure might help as
well.

Regards,
Peter

> Regards
> Sridhar
>
>
>
> On Thursday, September 24, 2015 8:23 AM, Peter Crosthwaite
> <crosthwaitepeter@gmail.com> wrote:
>
>
> On Wed, Sep 23, 2015 at 8:41 AM, Peter Maydell <peter.maydell@linaro.org>
> wrote:
>> On 23 September 2015 at 03:48, sridhar kulkarni <sridhar_kulk@yahoo.com>
>> wrote:
>>> Hi Peter,
>>>
>>> I was able to progress well using the BE8 work in the branch that you
>>> pointed out. I am experiencing floating point issue. The qemu just exits,
>>> by
>>> putting a message that "floating point exception(core dumped)". I suppose
>>> QEMU do support floating point operations. I heard about hard floating
>>> point
>>> and soft floating point support. Is there any configuration option in
>>> QEMU
>>> for floating point?
>>
>> QEMU's floating point support for ARM is good and known to work.
>> If QEMU exits with a coredump then that is either:
>>  * your test binary is dumping core due to a bug in your test
>>    (assuming you're using linux-user mode)
>>  * a bug in QEMU (unlikely but not impossible)
>>
>> If you can provide a reproducible test case we can have a look at it.
>>
>
> Yes, so the thing stopping me upstreaming this was a reasonable test.
> Can I have a look at your reproducer?
>
> Regards,
>
> Peter
>
>> thanks
>> -- PMM
>
>
>



  

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