kexec_file: adjust declaration of kexec_purgatory

Defining kexec_purgatory as a zero-length char array upsets compile time
size checking.  Since this is built on a per-arch basis, define it as an
unsized char array (like is done for other similar things, e.g.  linker
sections).  This silences the warning generated by the future
CONFIG_FORTIFY_SOURCE, which did not like the memcmp() of a "0 byte"
array.  This drops the __weak and uses an extern instead, since both
users define kexec_purgatory.

Change-Id: I0bc8e57b155461d6c8c904e82eff6554f07f290b
Link: http://lkml.kernel.org/r/1497903987-21002-4-git-send-email-keescook@chromium.org
Signed-off-by: Kees Cook <keescook@chromium.org>
Acked-by: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Daniel Micay <danielmicay@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Git-commit: e2ae8ab4b571e2e4094a28acb60649bc2732c67f
Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
Signed-off-by: Olav Haugan <ohaugan@codeaurora.org>
2 files changed