How to dynamically compute space for LMA of .data section in ld script?

[Jeffi Edward.J]

Ian Lance Taylor-3 wrote:
> 
> "Jeffi Edward.J" <j.jeffi@yahoo.co.in> writes:
> 
>> Since I'm porting the existing script (from diab) written for my
>> application
>> to GNU ld, I have to follow the semantics used in the existing script.
>> Does
>> it really make sense to have two .data sections within RAM itself? Since
>> I'm
>> very new to embedded domain, I'm not able to imagine indepth for the
>> necessity of two .data sections in RAM. Will it cause any problem if I
>> have
>> only .data section (next to .text section, and LMA=VMA for .data)? How
>> does
>> having two .data sections add value to memory protection?
> 
> Having two adjacent .data sections does not help with memory
> protection as far as I can see.
> 
> Other than a ROM/RAM distinction, one reason to use two .data sections
> is to permit the embedded system to do a hot reboot.  You can restart
> the program by copying the .data from LMA to VMA and jumping to the
> start address.  This assumes that there has been no memory corruption,
> of course.
> 
> Ian
> 
> 

Thanks a lot Ian. I could clearly understand the need of having two .data
sections in RAM which facilitates warm reboot. :)

Jeffi

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