linkcmds file

[Teng Chee Wan Philip]

I have looked at that linker script documentation, and tried several things, but it does not seems to work.  It seems like the *(.text*) was overriding all the rest of the input section description.  I tried using EXCLUDE_FILE but there was no effect.  The other issue seems to be that the object code was stored in /o-optimize/ directory.  I am not sure how to include that path into the EXCLUDE_FILE keyword to instruct the linker to ignore the application object code when setting the address for the rest.

I was hoping that someone can show me the proper way to modify this file.

In my application, most of the time the binary image changes because of the application code, rather than the operating system code.  By separating the operating systems code from the application, the static address of the operating system function calls will not change.  Indirectly, there will be "minimal" change in the binary image, when you re-compile the application+OS image.  And I can perform a binary patch, with a smaller patch file.  The other alternative is to move the operating system .text section up, before the application code .text.  I am not sure how to do that too.  Any ideas?

Thanks.

Regards,
Philip

-----Original Message-----
From: Chris Johns [mailto:chrisj at rtems.org] 
Sent: Wednesday, October 07, 2009 12:04 PM
To: Teng Chee Wan Philip
Cc: rtems-users at rtems.org
Subject: Re: linkcmds file



Teng Chee Wan Philip wrote:
> Hi,
> 
> I need some help here.  I am thinking of locating my application .text section to a different location from the operating system .text. Currently, in the linkcmds file, all the .text sections are located together because of the *(.text*) input section description.  The envisaged memory map goes like this:
> 
> .text (operating system)		0x02000000
> .text (applications, xx.o, yy.o)	0x02080000
> .data (os + apps)		following .text 
> .bss				0x02100000
> 
> Does anyone know how I can modify the linkcmds file to achieve that?  Any help will be greatly appreciated. Thanks.
>

Take a look at this page:

http://sourceware.org/binutils/docs-2.19/ld/Input-Section-Basics.html#Input-Section-Basics

and specifically the part on including sections for a specific file. 
Maybe that can help. The complication comes with other data in the flash 
or ROM memory that is part of the application but not at the separated 
address

Why do want to keep the application code separate ?

Regards
Chris