Problem with AMD64 ld with linker script

Daniel Jacobowitz drow@false.org
Fri Oct 6 04:54:00 GMT 2006


On Thu, Oct 05, 2006 at 07:00:33PM +0200, Peter Bindels wrote:
> As soon as I use a linker script, the alignments for all sections
> immediately jump to 2^20, with no possible way to get the alignment
> down. As a result of that, the .text is at 0x100000, .data is at
> 0x200000 and .init (kernel-specific section) is at 0x300000. That
> results in a binary over 3 megabytes in size, albeit very sparse,
> where I wanted about a 64k binary.

I experimented with this.  It's doing what you asked it to.  It's the
maximum legal page size being enforced: you can't map pages from the
binary file to the right VMAs if they're misaligned in the file
relative to the page size. You'll see that using ld -N completely
eliminates them.  That may be the right answer for your usage, if
you aren't interested in dynamic paging.

You asked for your PHDRs to be at 0x100000 intervals.  To put sections
in them, you're going to have to align them at file offsets equal to
their VMAs, modulus 0x100000.  Which is not what you really want, is
it?

-- 
Daniel Jacobowitz
CodeSourcery



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