Sam Ravnborg pointed out that Documentation/kbuild/makefiles.txt already
says this is what it's for.  This patch makes the reality live up to the
documentation.  This fixes the problem of LDFLAGS_BUILD_ID getting into too
many places.

Signed-off-by: Roland McGrath <roland@redhat.com>
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

* git://git.kernel.org/pub/scm/linux/kernel/git/sam/kbuild: (33 commits)
  xtensa: use DATA_DATA in xtensa
  powerpc: add missing DATA_DATA to powerpc
  cris: use DATA_DATA in cris
  kallsyms: remove usage of memmem and _GNU_SOURCE from scripts/kallsyms.c
  kbuild: use -fno-optimize-sibling-calls unconditionally
  kconfig: reset generated values only if Kconfig and .config agree.
  kbuild: fix the warning when running make tags
  kconfig: strip 'CONFIG_' automatically in kernel configuration search
  kbuild: use POSIX BRE in headers install target
  Whitelist references from __dbe_table to .init
  modpost white list pattern adjustment
  kbuild: do section mismatch check on full vmlinux
  kbuild: whitelist references from variables named _timer to .init.text
  kbuild: remove hardcoded _logo names from modpost
  kbuild: remove hardcoded apic_es7000 from modpost
  kbuild: warn about references from .init.text to .exit.text
  kbuild: consolidate section checks
  kbuild: refactor code in modpost to improve maintainability
  kbuild: ignore section mismatch warnings originating from .note section
  kbuild: .paravirtprobe section is obsolete, so modpost doesn't need to handle it
  ...

This change passes the --build-id when linking the kernel and when linking
modules, if ld supports it.  This is a new GNU ld option that synthesizes an
ELF note section inside the read-only data.  The note in this section contains
unique identifying bits called the "build ID", which are generated so as to be
different for any two linked ELF files that aren't identical.  The build ID
can be recovered from stripped files, memory dumps, etc.  and used to look up
the original program built, locate debuginfo or other details or history
associated with it.  For normal program linking, the compiler passes
--build-id to ld by default, but the option is needed when using ld directly
as we do.

Signed-off-by: Roland McGrath <roland@redhat.com>
Cc: Andi Kleen <ak@suse.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Richard Henderson <rth@twiddle.net>
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>