Re: ld x86-64 bug

[Alan Modra]

On Mon, Feb 10, 2003 at 03:33:44PM -0500, Daniel Jacobowitz wrote:
> A question that's come up before:  if you know the maximum page size
> used by an operating system, does shrinking MAXPAGESIZE (as long as it
> stays above that limit) impact the ABI?  Or does it only impact
> compatibility with some future potential OS which uses a larger page
> size?

I suppose it depends on what is written into the ABI.  :)  For example,
the x86 ELF psABI says:

"Virtual addresses and file offsets for the Intel386 architecture
segments are congruent modulo 4KB (0x1000) or larger powers of 2.
Because 4 KB is the maximum page size, the files will be suitable 
for paging regardless of physical page size."

So reducing MAXPAGESIZE below 4k would violate the ABI even if some
operating system only required 1k pages.  In practical terms, the
only effect would be incompatibility with some future version of
the OS with larger page size.

I note that the x86_64 psABI references the x86 one, and doesn't
respecify page size, so 4k should be good for x86_64.

-- 
Alan Modra
IBM OzLabs - Linux Technology Centre