[SeaBIOS] 16 Segementation help

[Daniel Castro]

Thank you vey much Kovin,
Sorry about that, let me then complement the code to make it more
accurate to the one I am using.

On Thu, Mar 15, 2012 at 9:42 PM, Kevin O'Connor <kevin at koconnor.net> wrote:
> On Thu, Mar 15, 2012 at 07:33:10PM +0900, Daniel Castro wrote:
>> Kevin, I greatly appreciate your help. Sorry to bother you again.
>>
>> Could you please check the following sample code, I am sure I am doing
>> something wrong, but I am on the right path:
>
> It would help if you sent actual code samples.  The details are
> important.
>
>> I have:
>> struct xendrive_s * xd = conteiner_of(op->drive_g,...)
>
> GET_GLOBAL(op->drive_g) -- as that is a memory access.
>
>> struct blk_info * bi = GLOBALFLAT2GLOBAL($(GET_GLOBALFLAT(xd)->info);
>
> I don't know what $ does.

Sorry that was a typo it is a "&" I am trying to create a pointer to a
struct inside the parent of drive_g; The struct xendrive_s has two
structs: drive and blk_info; xendrive_g was created using mallow_fseg.
Inside xendrive_g there is blk_info which have two pointers to structs
created through xen macros, they were created with
memalign_alow(4096,4096).

I have to do macros access to those to structs. Like this:
RING_GET_REQUEST(bi->private,bi->private->req_prod_pvt); //this
changes some indexes inside and returns a pointer to indicate where to
put the request.
Should I just but the GET_GLOBALs and hope for the best, if does not
work I should expand the macro and rewrite it, right?

Thanks again Kevin, your are being the most helpful.

Daniel

>
>> To test I do:
>> dprintf(1,"DEBUG test xendrive %p and an int
>> %d.\n",GET_GLOBALFLAT(xd),GET_GLOBALFLAT(GET_GLOBALFLAT(bi)->buffer_gref));
>
> Neither "bi" nor "xd" is a non-stack memory access so they shouldn't
> be wrapped.  "bi->buffer_gref" is a memory access.  So it should look
> like dprintf("...", xd, GET_GLOBALFLAT(bi->buffer_gref)).  (This is
> assuming the pointer in buffer_gref was obtained via malloc_fseg.)

Only when I initialize the stack variables with memory addresses and
memory address access do I requiere GET_GLOBAL, GET_GLOBALFLAT or
GLOBALFLAT2GLOBAL. RIght?

>
> -Kevin



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| |   | Daniel Castro,                |
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