Garbage values in LMA of .data section

[Ian Lance Taylor]

"Jeffi Edward.J" <j.jeffi@yahoo.co.in> writes:

> I do copying of .data from LMA to VMA as follows:
>
> memcpy(__data_start, __code_end, (__data_end - __data_start));

How did you declare those symbols in your C program?


> Using --print-map option to linker, I generated map file of symbols.
> I found the LMA of .data section in map file.
> VMA of my .data is 0x3000000(as per above skeleton script).
> Assume my LMA is 0x2000000 (__code_end).
> I calculated the offset of that global variable with respect to LMA region.
> I found in my LMA region itself, the global variables are not loaded
> properly. i.e the global variable has the same junk value in LMA region.
>
> I found from map file that some additional section are generated in between
> .data and .sdata.
> .eh_frame, .jcr, .data.rel.local, .data.rel.ro.local, .data.rel.
>
> Are these sections needed? Is my LMA region corrupted my any other section?

Those sections are needed.


> On seeing the map file, I found that many additional section
> .text._ZN6DArray***, .rela.text._ZN6DArray***, .rela.sdata.__ZTIS***,
> .rela.rodata.__ZTIS***.

Hmmm, C++.  Do you see any .gnu.linkonce sections?  If not, that is
fine.  If you do, you should mention them in your linker script.


Unfortunately, I don't know what is going on.  If the map file shows
that the data sections are being handled properly, then you should not
see junk in the LMA space.  I don't know what could cause that.

Ian