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Re: elf-powerpc pagesize discrepancy?


   From: jtc@redback.com (J.T. Conklin)
   Date: 27 Jul 1999 15:30:49 -0700

   I spent some time yesterday tracking down why the linker was adding an
   large amount of space between the end of the text and the beginning of
   the data segment in my images.  I tracked this down to the line:

	   ${RELOCATING+. ${DATA_ADDR- ALIGN(8) + ${MAXPAGESIZE}};}

   Which adjusts the address of the next page.  Normal enough, but I was
   suprised to discover that MAXPAGESIZE is defined to be 0x40000.  This
   struck me as an odd value for a processor with 4K pages.  

   But I checked with the SysV ABI PPC Supplement and discovered that it
   allows operating systems to cluster physical pages into logical pages
   up to 0x10000 bytes in size (which cooresponds to ELF_MAXPAGESIZE in
   bfd/elf32-ppc.c).  But I can't find anything that refers to a 0x40000
   byte page.  Similarly, the SysV ABI recommends a 0x2000000 text start
   address, while we use 0x1800000.

I put those numbers in there long before there was a PowerPC ELF ABI.
I just checked in a patch to change the MAXPAGESIZE number to the
correct value.  I'm less certain about the default text start address,
though we should probably change that as well.

Ian

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