Question about elf data segment address adjustment

[Nick Clifton]

Hi Douglas,

> In ld/scripttempl/elf.sc about line 562 there's a comment that pre-dates the 1999 sourceware import, so I can't track it down.

Searching through the old CVS logs, I found this:

  revision 1.32
  date: 1996/02/15 20:28:54;  author: ian;  state: Exp;  lines: +2 -14
	* scripttempl/elf.sc: Don't skip a page in virtual memory space if
	the text segment ends exactly on a page boundary.


> The adjustment described by the comment sometimes leads to an attempted out of range load of a system global variable.

Could you be more specific about this please ?  Is there an example
that we could look at ?


> The comment is:
> 
> /* Adjust the address for the data segment.  We want to adjust up to
>      the same address within the page on the next page up.  */

Note - there is a similar comment, and adjustment, for the .rodata section as well.
 
> What is the reason for this adjustment to the data segment starting address?  
> Why not, for example, adjust up to the next multiple of 0x10000?

Because we do not want to waste pages of memory if the page size is small.

Cheers
  Nick