Reserving memory in linker script file

Jeroen Boonen

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Aug 5, 2004, 10:16:03 AM8/5/04

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Hi,

Is it possible to reserve some memory in the linker script file

ex:
MEMORY
{
sram (WXAI) : org = 0x00000100, len = 256K - 0x100
flash (RX) : org = 0x01000000, len = 2M
}

In the flash I need some reserved spaces were no code my be placed by the
linker...(space is used to add some headers after compilation and linking)

Any help

Jeroen

42Bastian Schick

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Aug 6, 2004, 4:25:10 AM8/6/04

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On Thu, 05 Aug 2004 14:16:03 GMT, "Jeroen Boonen" <j...@pandora.be>
wrote:

SECTIONS
{
.reserved :
{
. += <enter amount here>;
} > flash;

/* more sections */
}

--
42Bastian
Do not email to bast...@yahoo.com, it's a spam-only account :-)
Use <same-name>@epost.de instead !

Jeroen Boonen

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Aug 6, 2004, 11:23:43 AM8/6/04

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Hi Bastian,

OK, your solution is a way of doing that, but what I want is that the
compiler automatically places code "around" the reserved space. I need this
for by boot code.
The boot code needs to start at address 0, then at 8K, there is a reserved
place, then further again boot code.
In advance I don't know the size of the first and second boot code...So what
I want is that the linker places code beginning at 0 until needed, but not
the second sector of 8K

Is there a way to do this?

Jeroen

42Bastian Schick

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Aug 12, 2004, 12:41:49 AM8/12/04

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Hi Jeroen

>OK, your solution is a way of doing that, but what I want is that the
>compiler automatically places code "around" the reserved space. I need this
>for by boot code.
>The boot code needs to start at address 0, then at 8K, there is a reserved
>place, then further again boot code.
>In advance I don't know the size of the first and second boot code...So what
>I want is that the linker places code beginning at 0 until needed, but not
>the second sector of 8K
>
>Is there a way to do this?

Now I understand, I had the same problem with the MCF5282, the Flash
needs some 24bytes for protection and these were not the start or end
:(

But I found no solution other than splitting my code:

MEMORY {
rom1 (rx) : org=0, len = 0x400;
cfg (r) : org=0x400, len = 24;
rom (rx) : org=0x400+24, len 0x80000-0x400-24
}

And then filling rom1 as much as possible.

Ralf Ebeling

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Aug 12, 2004, 4:23:59 AM8/12/04

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42Bastian Schick wrote:

>>OK, your solution is a way of doing that, but what I want is that the
>>compiler automatically places code "around" the reserved space. I need this
>>for by boot code.
>>The boot code needs to start at address 0, then at 8K, there is a reserved
>>place, then further again boot code.
>>In advance I don't know the size of the first and second boot code...So what
>>I want is that the linker places code beginning at 0 until needed, but not
>>the second sector of 8K
>>
>>Is there a way to do this?
>
> Now I understand, I had the same problem with the MCF5282, the Flash
> needs some 24bytes for protection and these were not the start or end
> :(
>
> But I found no solution other than splitting my code:
>
> MEMORY {
> rom1 (rx) : org=0, len = 0x400;
> cfg (r) : org=0x400, len = 24;
> rom (rx) : org=0x400+24, len 0x80000-0x400-24
> }
>
> And then filling rom1 as much as possible.

What's about using a dummy data section (reserving the space needed
only) placed at a fixed location that won't be initialized on startup?

Ralf

42Bastian Schick

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Aug 13, 2004, 11:31:58 AM8/13/04

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>>
>> But I found no solution other than splitting my code:
>>
>> MEMORY {
>> rom1 (rx) : org=0, len = 0x400;
>> cfg (r) : org=0x400, len = 24;
>> rom (rx) : org=0x400+24, len 0x80000-0x400-24
>> }
>>
>> And then filling rom1 as much as possible.
>
>What's about using a dummy data section (reserving the space needed
>only) placed at a fixed location that won't be initialized on startup?

I don't see how. The problem is, the GNU linker does not fill up the
section automatically (the HCS12-GNU people discussed this a lot).

Something like:

.rom1 : { *(.text) } >rom1
.rom2 : { *(.text) } >rom2
would be nice, where ld puts as much as possible into rom1 and then
steps over to rom2.

Richard McCord

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Aug 16, 2004, 1:07:20 PM8/16/04

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This is how I do it
MEMORY {
    ram          ORG = 0x0                     , LEN = 0x80000
    boot         ORG = 0x80000             , LEN = 0x800
    extram      ORG = 0x80000+0x800 , LEN = 0x100000
}

SECTION {
    .test                                        :> ram
    .bootsection    PAD(0x800)    :> boot
    .data                                       :>extram
}

NOTE: sections can not over lap.

Rick

42Bastian Schick

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Aug 18, 2004, 9:43:20 AM8/18/04

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On Mon, 16 Aug 2004 10:07:20 -0700, Richard McCord
<rmc...@raytheon.com> wrote:

><!doctype html public "-//w3c//dtd html 4.0 transitional//en">
><html>
><more html kicked ...>
What the heck ...