Re: Does GDB use VMA addresses when uploading an image to debug in a remote target?

[Daniel Jacobowitz <drow at false dot org>]

On Wed, Feb 22, 2006 at 03:12:43PM -0300, Fabrício de Novaes wrote:
> Hi all,
> 
> 
> I have a GCC application that will run in a board with an ERC32
> (SPARC) processor. For many reasons, this app has to run in RAM, not
> ROM.
> 
> So, the ELF32 image has a ".boot" section which starts the board and
> copies the main program from a ".text" section to RAM. This .text
> section has different LMA (pointing to ROM) and VMA (RAM) addresses,
> as you can see below:
> 
> Idx Name          Size      VMA       LMA       File off  Algn
>   0 .boot         00001320  00000000  00000000  000000b4  2**0
>                   CONTENTS, ALLOC, LOAD, READONLY, CODE
>   1 .text         0001d1b0  02001000  00001320  000013d8  2**3
>                   CONTENTS, ALLOC, LOAD, CODE
> [...]
> 
> 
> I'm trying to debug this app using GDB and a simulator. My problem is
> that, when I load the image to debug, the .text section is already in
> the 0x2001000 address (VMA), and the LMA area (starting from 0x1320)
> is empty - so I can't debug appropriately the routine that copies the
> .text section to RAM.
> 
> I'd like to know if GDB loads sections from an ELF file to a target
> using the VMA addresses and, if yes, if it's possible to change this
> behavior and tell it to send my .text section to its LMA address.
> 
> Any answer or comment will be very appreciated.

Replying to this old report again...

I was absolutely convinced for a long time that GDB's "load" wrote to
the VMA, a very confusing behavior.  I remember another bug being
reported that seemed to illustrate this also, but I can't find it.
However, today I actually tried it, and it did exactly the right thing:
wrote to the LMA!

Fabrício, if you still can reproduce this problem, could you send me
the output of "load" and tell me what version of GDB you were using?

-- 
Daniel Jacobowitz
CodeSourcery