Messages in this thread | | | Date | Mon, 19 May 2008 13:41:41 +0900 | From | Paul Mundt <> | Subject | Re: [PATCH] binfmt_elf_fdpic: Magical stack pointer index, for NEW_AUX_ENT compat. |
| |
On Fri, May 16, 2008 at 12:22:33PM +0100, David Howells wrote: > Paul Mundt <lethal@linux-sh.org> wrote: > > > While implementing binfmt_elf_fdpic on SH it quickly became apparent > > that SH was the first platform to support both binfmt_elf_fdpic and > > binfmt_elf, as well as the only of the FDPIC platforms to make use of the > > auxvt. > > > > Currently binfmt_elf_fdpic uses a special version of NEW_AUX_ENT() where > > the first argument is the entry displacement after csp has been adjusted, > > being reset after each adjustment. As we have no ability to sort this out > > through the platform's ARCH_DLINFO, this index needs to be managed > > entirely in create_elf_fdpic_tables(). Presently none of the platforms > > that set their own auxvt entries are able to do so through their > > respective ARCH_DLINFOs when using binfmt_elf_fdpic. > > > > In addition to this, binfmt_elf_fdpic has been looking at > > DLINFO_ARCH_ITEMS for the number of architecture-specific entries in the > > auxvt. This is legacy cruft, and is not defined by any platforms in-tree, > > even those that make heavy use of the auxvt. AT_VECTOR_SIZE_ARCH is > > always available, and contains the number that is of interest here, so we > > switch to using that unconditionally as well. > > > > As this has direct bearing on how much stack is used, platforms that have > > configurable (or dynamically adjustable) NEW_AUX_ENT calls need to either > > make AT_VECTOR_SIZE_ARCH more fine-grained, or leave it as a worst-case > > and live with some lost stack space if those entries aren't pushed (some > > platforms may also need to purposely sacrifice some space here for > > alignment considerations, as noted in the code -- although not an issue > > for any FDPIC-capable platform today). > > > > Signed-off-by: Paul Mundt <lethal@linux-sh.org> > > Acked-by: David Howells <dhowells@redhat.com>
As the SH FDPIC stuff depends on this, I'll fold this in to my 2.6.27 tree with the above Acked-by, which will trickle in to -mm and linux-next directly.
| |