Re: [PATCH] i386 vsyscall DSO implementation

[David Mosberger <davidm@napali.hpl.hp.com>]

I like this.  Even better would be if all platforms could do the same.
I'm definitely interested in doing something similar for ia64 (the
getunwind() syscall was always just a stop-gap solution).

I assume that these kernel ELF images would then show up in
dl_iterate_phdr()?

To complete the picture, it would be nice if the kernel ELF images
were mappable files (either in /sysfs or /proc) and would show up in
/proc/PID/maps.  That way, a distributed application such as a remote
debugger could gain access to the kernel unwind tables on a remote
machine (assuming you have a remote filesystem).

	--david

>>>>> On Thu, 24 Apr 2003 19:10:50 -0700, Roland McGrath <roland@redhat.com> said:

  >> We already embed a cpio archive into __initdata space.  What
  >> about putting the images in there, and either copying the data
  >> out of initramfs, or, directly referencing the pages that store
  >> each image?

  Roland> It doesn't matter to me, but I don't see the benefit to
  Roland> doing that.  It's rather unlike what initramfs is used for
  Roland> now and would need a bunch of extra code to accomplish
  Roland> something very simple.

  Roland> The DSO images are not stored page-aligned and padded in the
  Roland> kernel image, so the pages can't be used directly.  Storing
  Roland> them that way would use more space in the kernel image on
  Roland> disk, and then you'd want to free initdata page containing
  Roland> the unused one.