Crash in _User_extensions_Thread_create

[Matthew J Fletcher]

Hi,

Following up to myself,.. i added the following bit of Thumb asm before
boot_card() in start.s

ldr r1, =_etext // -> ROM data start
ldr r2, =_data // -> data start
ldr r3, =_edata // -> end of data
loop_a: ldr r0,[r1]
           str r0,[r2]
           add r1,#4
           add r2,#4
           cmp, r2,r3 // check if data to move
           blo loop_a

along with the _data and _edata symbols to mark the start and end of the
.data section.

Not the most pretty Thumb asm i guess but it makes the rtl22xx BSP now have
initialised variables with the correct value.

- Matthew


On 21 February 2013 13:45, Matthew J Fletcher <amimjf at gmail.com> wrote:

> Sebastian,
>
> Ok, i've got the latest GIT sources, but i still dont see how the rtl22xx
> BSP works (and it does not work for me).
>
> start.s does not do any data section copy, it just does a zero'ing of the
> bss and then calls boot_card(), how can that work with initialised data ?
>
> the start.s thats in the arm/shared folder calls the bsp_start_hook_1
> which does the bsp_start_copy_sections() which uses the hand rolled memcpy
> function to copy data as well as other sections.
>
> Is the rtl22xx just a broken BSP that i should not be using ?
>
> - Matthew
>
>
>
> On 21 February 2013 08:55, Sebastian Huber <
> sebastian.huber at embedded-brains.de> wrote:
>
>> On 02/20/2013 09:55 PM, Joel Sherrill wrote:
>>
>>> On 2/20/2013 2:39 PM, Matthew J Fletcher wrote:
>>>
>>>> Hi,
>>>>
>>>> Ok so looking at the rtl22xx BSP as an example i can see the linker
>>>> creates a .data section like so,
>>>>
>>>>    .data :
>>>>    {
>>>>      *(.data)
>>>>      *(.data.*)
>>>>      *(.gnu.linkonce.d*)
>>>>      *(.jcr)
>>>>      SORT(CONSTRUCTORS)
>>>>      _edata = .;
>>>>    } > sdram
>>>>
>>>> but in start.s there is no reference to the data section or the _edata
>>>> symbol, so i've got no idea how that could setup the data section with
>>>> the initialised variables in it.
>>>>
>>>> Thinking for a minute, would the linker script not need a symbol for
>>>> both the beginning and the end of the data section so start.s knows the
>>>> range to copy ? and then a loop in start.s to copy the data.
>>>>
>>>> I wonder if these BSP's are only suitable for execute from flash systems
>>>> where you dont need to do the store -> ram copy of initialised data.
>>>>
>>>> Thats ultimately how i will run but i am running from RAM at the moment
>>>> to ease (i thought !) being up and debugging.
>>>>
>>>>  I don't know this BSP that well. If the .data section has the proper
>>> values in it
>>> when you get to boot_card(), then it is OK.
>>>
>>> In some systems, the RAM would be loaded from Flash by start.S or
>>> something
>>> similarly early.
>>>
>>> In all cases, if you get to rtems_initialize_executive_**early() (or
>>> even the
>>> bsp_get_work_area() methods) and .data isn't right, you are in trouble.
>>>
>>> Sebastian Huber should comment.
>>>
>>
>> For ARM I would use the current RTEMS master branch and not RTEMS 4.10.
>>  The ARM BSPs use now a shared linker command file and a BSP specific
>> memory map definition.
>>
>> --
>> Sebastian Huber, embedded brains GmbH
>>
>> Address : Dornierstr. 4, D-82178 Puchheim, Germany
>> Phone   : +49 89 189 47 41-16
>> Fax     : +49 89 189 47 41-09
>> E-Mail  : sebastian.huber at embedded-**brains.de<sebastian.huber at embedded-brains.de>
>> PGP     : Public key available on request.
>>
>> Diese Nachricht ist keine geschäftliche Mitteilung im Sinne des EHUG.
>> ______________________________**_________________
>> rtems-users mailing list
>> rtems-users at rtems.org
>> http://www.rtems.org/mailman/**listinfo/rtems-users<http://www.rtems.org/mailman/listinfo/rtems-users>
>>
>
>
>
> --
>
> regards
> ---
> Matthew J Fletcher
>
>


-- 

regards
---
Matthew J Fletcher
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.rtems.org/pipermail/users/attachments/20130221/06ae805f/attachment-0001.html>