Réf : Réf : Re: Réf : Re: Réf : Re: Réf : Re: Init of the memory by RTEMS
Leonard Bise
leonard.bise at syderal.ch
Thu Dec 10 13:53:49 UTC 2009
Actually using CONFIGURE_EXECUTIVE_RAM_WORK_AREA does not change anything.
That's because in bsp_start function the following overwrites this value:
work_space_start = (unsigned char *)rdb_start;
work_space_start -= BSP_Configuration.work_space_size;
BSP_Configuration.work_space_start = work_space_start;
rdb_start has the value 0x401F FFF0 which is the end of my RAM. rdb_start
is set in start.S like so : set (SYM(rdb_start)), %g6 ! End of
work-space area but I can't seem to find when is the g6 register
loaded...
Basically I don't see how to solve my problem because if in the linker
script I specify a RAM size smaller, the BSP ignores it and use rdb_start
instead which has the last address of my RAM but I don't know how it gets
it. Specifying a start addr using the CONFIGURE_EXECUTIVE_RAM_WORK_AREA
define does not do anything either.
Is there any other possibility I'm missing there?
Léonard.
Leonard Bise <leonard.bise at syderal.ch>
Envoyé par : rtems-users-bounces at rtems.org
10.12.2009 14:18
A
Joel Sherrill <joel.sherrill at oarcorp.com>
cc
"rtems-users at rtems.org" <rtems-users at rtems.org>
Objet
Réf : Re: Réf : Re: Réf : Re: Réf : Re: Init of the memory by RTEMS
After looking around I found exactly where the data is being cleared.
In function _Workspace_Handler_initialization, RTEMS clears the whole
workspace.
This operation is controlled by a flag but it is always set to true so
there is no easy way around it.
The start address for this operation is 0x401df7f0 and the size is 133120.
I guess I can use CONFIGURE_EXECUTIVE_RAM_WORK_AREA to specify a start
address for the workspace that is not so close from the end of the RAM and
thus it won't clear all of it. Am I correct?
Léonard.
Joel Sherrill <joel.sherrill at oarcorp.com>
10.12.2009 13:15
A
Leonard Bise <leonard.bise at syderal.ch>
cc
Aleix Conchillo Flaqué <aconchillo at ice.csic.es>, "rtems-users at rtems.org"
<rtems-users at rtems.org>
Objet
Re: Réf : Re: Réf : Re: Réf : Re: Init of the memory by RTEMS
On 12/10/2009 01:37 AM, Leonard Bise wrote:
>
> I tried this methode but surprinsingly the memory in this area STILL
> gets erased. I don't know by what and it does not make any sense
either.
>
> 401e0000 g *ABS* 00000000 _RAM_END
>
> That seems correct but something is STILL clearing that damn memory !
>
Are you doing a CPU reset?
Do you have GRMON? I think it clears memory also.
> I'm seriously lost now..
>
> Léonard.
>
>
>
>
> *Joel Sherrill <joel.sherrill at oarcorp.com>*
>
> 09.12.2009 20:28
>
>
> A
> Aleix Conchillo Flaqué <aconchillo at ice.csic.es>
> cc
> Leonard Bise <leonard.bise at syderal.ch>,
"rtems-users at rtems.org"
> <rtems-users at rtems.org>
> Objet
> Re: Réf : Re: Réf : Re: Init of the memory by RTEMS
>
>
>
>
>
>
>
>
>
> On 12/09/2009 10:24 AM, Aleix Conchillo Flaqué wrote:
> > Why don't you just change the start of your Application? For example:
> >
> >
> > MEMORY
> > {
> > ram : ORIGIN = 0x40020000, LENGTH = 2M - 128 K
> > }
> >
> > RTEMS will not modify anything from 0x40000000 to 0x4001FFFF.
> >
> Or simply leave ORIGIN alone and subtract 128K from the LENGTH.
> Either way works. But you can't tell RTEMS about it. :)
>
> --joel
> >
> > On Wed, Dec 9, 2009 at 14:26, Leonard Bise <leonard.bise at syderal.ch
> > <mailto:leonard.bise at syderal.ch>> wrote:
> >
> >
> > Thanks for your answer Joel.
> >
> > We are using the 4.6 version of RTEMS so I guess the memory must
> > be cleared.
> >
> > I already use a customized linkcmds file in this application, to
> > specify various sections and other stuff.
> >
> > Thats what I modified for my RAM size :
> >
> > RAM_SIZE = 2M ;
> >
> > EEPROM_SIZe = 512K ;
> >
> > PROM_SIZE = 64K ;
> >
> > RAM_END = RAM_START + RAM_SIZE;
> >
> > MEMORY
> > {
> > rom : ORIGIN = 0x00000000, LENGTH = 64K
> > ram : ORIGIN = 0x40000000, LENGTH = 2M
> > eeprom : ORIGIN = 0x60000000, LENGTH = 512K
> > }
> >
> > >If you do not reserve the memory area out of the linkcmds, then
> > >it is likely to be used for some other purpose and overwritten.
> >
> > How can I reserve memory ? I tried creating a section like this :
> >
> > sCCA_Main 0x401E7000: {
> > *(sCCA_Main)
> > } > ram
> >
> > then my var in the code looks like this :
> >
> > uint32 PkgHW_CCA_main __attribute__ (( section ( "sCCA_Main" ) ) )
;
> >
> > But this does not work, the data I place in 0x401E7000 before
> > starting execution of my RTEMS apps is overwritten by 0.
> > Hope you can help.
> >
> > Léonard.
> >
> >
> >
> >
> > *Joel Sherrill <joel.sherrill at oarcorp.com
> > <mailto:joel.sherrill at oarcorp.com>>*
> >
> > 09.12.2009 14:16
> >
> >
> > A
> > Leonard Bise <leonard.bise at syderal.ch
> > <mailto:leonard.bise at syderal.ch>>
> > cc
> > Sebastian Huber
<sebastian.huber at embedded-brains.de
> > <mailto:sebastian.huber at embedded-brains.de>>,
> > "rtems-users at rtems.org <mailto:rtems-users at rtems.org>"
> > <rtems-users at rtems.org <mailto:rtems-users at rtems.org>>
> > Objet
> > Re: Réf : Re: Init of the memory by RTEMS
> >
> >
> >
> >
> >
> >
> >
> >
> >
> > On 12/09/2009 06:41 AM, Leonard Bise wrote:
> > >
> > > I forgot to mention it.
> > >
> > > I'm using RTEMS for the LEON2 platform.
> > >
> > Version?
> > > Also I'm not too sure how to know the address of the workspace
> > or heap?
> > >
> > They are next to each other and the linkcmds and symbol
> > table from your application should give the information.
> >
> > Where did you override the RAM size? The linkcmds
> > has this:
> >
> > MEMORY
> > {
> > rom : ORIGIN = 0x00000000, LENGTH = 256M
> > ram : ORIGIN = 0x40000000, LENGTH = 1024M
> > }
> >
> > And the start.S zeroes out the BSS from "_edata"
> > to "_end".
> >
> > The addresses you mentioned will be part of the
> > unused memory from after the bss until the end of ram
> > and since you didn't tell the linkcmds or RTEMS about them,
> > they will be put in either the Workspace or C Program Heap
> > and used by something.
> >
> >
> >
> > --joel
> >
> > > Léonard.
> > >
> > >
> > >
> > > *Sebastian Huber <sebastian.huber at embedded-brains.de
> > <mailto:sebastian.huber at embedded-brains.de>>*
> > >
> > > 09.12.2009 11:31
> > >
> > >
> > > A
> > > Leonard Bise <leonard.bise at syderal.ch
> > <mailto:leonard.bise at syderal.ch>>
> > > cc
> > > rtems-users at rtems.org <mailto:rtems-users at rtems.org>
> > > Objet
> > > Re: Init of the memory by RTEMS
> > >
> > >
> > >
> > >
> > >
> > >
> > >
> > >
> > >
> > > Hi,
> > >
> > > which BSP do you use? Is the memory address 0x401E7000 part of the
> > > workspace or
> > > heap?
> > >
> > > CU
> > >
> > > --
> > > Sebastian Huber, embedded brains GmbH
> > >
> > > Address : Obere Lagerstr. 30, D-82178 Puchheim, Germany
> > > Phone : +49 89 18 90 80 79-6
> > > Fax : +49 89 18 90 80 79-9
> > > E-Mail : sebastian.huber at embedded-brains.de
> > <mailto: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 <mailto:rtems-users at rtems.org>
> > http://www.rtems.org/mailman/listinfo/rtems-users
> >
> >
>
>
> --
> Joel Sherrill, Ph.D. Director of Research& Development
> joel.sherrill at OARcorp.com On-Line Applications Research
> Ask me about RTEMS: a free RTOS Huntsville AL 35805
> Support Available (256) 722-9985
>
>
>
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