Re: Cross debugger and load address (want download to VMA, not LMA)

[Bill Gatliff <bgat at billgatliff dot com>]

Toralf:


I usually just have two linker command scripts: one for flash, one for 
RAM.  They differ only in their specifications for LMA.

b.g.


Toralf Lund wrote:

> I want to debug the software for our new board via gdb or insight 
> built as a cross debugger. Now, the binary will usually be loaded via 
> flash, but executed mostly from RAM, so it is linked with VMA for 
> .text and .data set to RAM addresses, and LMA pointing to the flash 
> area (as required by the flash routine.) However, when running through 
> the debugger, I want to download directly to RAM, i.e. to VMA, but the 
> debugger tries to write to LMA (of course) by default. What's the 
> easiest way around this? Is there any way I can get the debugger to 
> pick up the VMA for each of the sections instead, and use those as 
> download target address? If not, is there any way to produce a version 
> of the binary with LMA = VMA for .text and .data, besides relinking 
> with a separate linker script? I've tried to use objcopy option 
> "--change-section-lma", but it's not easy to find the right parameters as
>
>   1. I don't know the VMA or LMA for .data in advance - just that it
>      follows immediately after .text
>   2. I can't calculate an offset as I don't know the .text LMA, either
>      - in the flash .text is preceded by a separate section containing
>      interrupt vectors and RAM init routines, but this is never copied
>      to RAM (so .text VMA is the beginning of RAM, but its LMA is *not*
>      the beginning of flash.)
>
> Ideas, anyone?
>
> (As usual, I'm posting to this list as I know of no other way to reach 
> people who build apps in way similar to the one discussed - the actual 
> questions may be slightly off-topic...)
>
> -Toralf
>
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--
Bill Gatliff
GNU-based embedded development, training and consulting services.
bgat@billgatliff.com



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