[MIT-Scheme-devel] Executable memory: some apps that work on RH9 don't on FC1

[Chris Hanson]

   Date: Mon, 17 Nov 2003 19:35:20 -0800
   From: Roland McGrath <address@hidden>

   > I should be able to tell the linker and loader that certain areas
   > are reserved.  That's possible with the linker, but I'm not aware
   > of any way to control the loader.

   I'm not sure what level of control you have in mind when you
   distinguish what you can specify to the linker and to the loader,
   or whether by "the loader" you mean the kernel's loading of
   executable files, or the dynamic linker's loading of DSOs, or both.
   I don't see why it's not sufficient to specify the layout you want
   at link time.  That you can do.  If your executable contains
   PT_LOAD program header entries for each region you want reserved,
   it will be.  You can use entries with none of PF_[RWX] set to get
   PROT_NONE mappings that you can overwrite later with MAP_FIXED
   mappings.

OK, so this is the piece that I'm missing.  Where can I learn more
about these header entries?  I don't see anything in the libc
reference about this, even though PT_LOAD is defined by libc.