[okl4-developer] [OKL2.1]spurious exception as soon as OKlinux forks init.

[Amit Daniel]

Geoffrey Lee wrote:
> 
> On Mon, Sep 29, 2008 at 05:16:26AM -0700, Amit Daniel wrote:
>> 
>> Dear All,
>> 
>> I have tested some test examples with okl microkernel and iguana. They
>> works
>> fine.
>> But when i try executing OKLinux as an application, spurious exception
>> starts coming. I am building the image file as,
>> tools/build.py machine=gta01 project=iguana wombat=True 
>> enable_fastpaths=False
>> This exception is coming as soon kernel tries to fork the /sbin/init
>> process. I tried to put some print in main interrupt handler but those
>> prints are not coming. so, the exception source is not clear.
>> 
> 
> Hi Amit
> 
> The exception handler for Linux processes is the syscall_loop(), not 
> interrupt_loop(), which I think may be what is confusing you.
> 
> Also, have you made any modifications to either the OKL4 or the OK Linux
> distribution in any way?  If so what have you changed?
> 
> 	-gl
> 
> Hi Geoffrey,
> 
> I have just made 1 change which is adding the solution for clzeq given in
> one of the previous mails in the mailing list. This clzeq instruction was
> causing exception and enable_fastpaths=false only disables 2 clz
> instruction. I am testing for s3c2440 board which is ARM920T based core.
> Modified file is : arch/arm/pistachio/v5/src/traps.spp
> The diff with the original is shown below,
> <         ldreq   r1,     [r0, #OFS_TCB_POST_SYSCALL_CALLBACK]
> <         clzeq   r1,     r1 /* r1 contains callback function, 0xFXXXXXXX
> */
> ---
>>        // ldreq   r1,     [r0, #OFS_TCB_POST_SYSCALL_CALLBACK]
>>       //  clzeq   r1,     r1 /* r1 contains callback function, 0xFXXXXXXX
>> */
>>       ldr     r1,     [r0, #OFS_TCB_POST_SYSCALL_CALLBACK]
> 224a226,228
>>       bne kernel_fixup
>>       normal_return:
> 233c237,241
> <         subnes  pc,     lr,     #1
> ---
>>    //     subnes  pc,     lr,     #1
>>       subs  pc,     lr,     #1
>>       kernel_fixup:
>>       cmp     r1,     #0
>>       beq     normal_return
> 
> Thanks,
> Amit Daniel
> 
> 
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>> 
>> 
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> 
> -- 
> 
> 
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