Syslinux - Sep 2012 - INT22h/000Dh

Hi,

I would like to use INT22h, function 000Dh, but I found that it is 
disabled in vector table:

in core/comboot.inc:
     int22_table:
         [...]
             dw comapi_err        ; 000D clean up then bootstrap
         [...]

The code of this function is present in this file (comapi_chainboot).
Why this function is disabled?

Regards
Piotr Romaniuk

PS
I am using syslinux-4.04.

Piotr Romaniuk wrote:
> Hi,
> 
> I would like to use INT22h, function 000Dh, but I found that it is 
> disabled in vector table:
> 
> in core/comboot.inc:
>     int22_table:
>         [...]
>             dw comapi_err        ; 000D clean up then bootstrap
>         [...]
> 
> The code of this function is present in this file (comapi_chainboot).
> Why this function is disabled?
It was likely an oversight in commit 1656aefeb6b7195db38d25065137c4f37655f33a
[1]:

shuffler: comboot interface to the new shuffler

Impact: new feature

COMBOOT interface to the new shuffler; resurrect comapi_chainboot as
that functionality is still potentially relevant.

[1]
http://git.kernel.org/?p=boot/syslinux/syslinux.git;a=commit;h=1656aefeb6b7195db38d25065137c4f37655f33a

Sebastian

Hi,

I added proper entry in vector table (i.e. comapi_chainboot), but after 
I call int22h/000Dh it hangs and does not start my code. Am I doing 
something wrong in setup of this interrupt arguments?

     com32sys_t input_regs, output_regs;
     input_regs.eax.l=0xd;
     input_regs.edx.l=0x0;
     input_regs.edi.l=OFFS(buffer);
     input_regs.ecx.l=512;
     input_regs.ebx.l=0x80;
     input_regs.esi.l=0x0;
     input_regs.ds=0;
     input_regs.es=0;

     __com32.cs_intcall(0x22, &input_regs, &output_regs);

The buffer contained simple code, just to signal if it is executed on GPIO:
     buffer:
         cli
         mov  $GPIO_PORT, dx
         mov  $GPIO_VALUE, al
         out  al, (dx)
     L:  jmp L

Regards
Piotr Romaniuk

PS
I run this on Atom E640.



On 09/04/2012 03:12 PM, Sebastian Herbszt wrote:
> Piotr Romaniuk wrote:
>> Hi,
>>
>> I would like to use INT22h, function 000Dh, but I found that it is 
>> disabled in vector table:
>>
>> in core/comboot.inc:
>>     int22_table:
>>         [...]
>>             dw comapi_err        ; 000D clean up then bootstrap
>>         [...]
>>
>> The code of this function is present in this file (comapi_chainboot).
>> Why this function is disabled?
>
> It was likely an oversight in commit 
> 1656aefeb6b7195db38d25065137c4f37655f33a [1]:
>
> shuffler: comboot interface to the new shuffler
>
> Impact: new feature
>
> COMBOOT interface to the new shuffler; resurrect comapi_chainboot as
> that functionality is still potentially relevant.
>
> [1] 
>
http://git.kernel.org/?p=boot/syslinux/syslinux.git;a=commit;h=1656aefeb6b7195db38d25065137c4f37655f33a
>
> Sebastian
>
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>

On 09/04/2012 05:07 AM, Piotr Romaniuk wrote:
> Hi,
>
> I would like to use INT22h, function 000Dh, but I found that it is
> disabled in vector table:
>
> in core/comboot.inc:
>      int22_table:
>          [...]
>              dw comapi_err        ; 000D clean up then bootstrap
>          [...]
>
> The code of this function is present in this file (comapi_chainboot).
> Why this function is disabled?
>
Because the shuffler API replaces it.  What are you trying to do?

	-hpa

-- 
H. Peter Anvin, Intel Open Source Technology Center
I work for Intel.  I don't speak on their behalf.