kexec: create a new config option CONFIG_KEXEC_FILE for new syscall
Currently new system call kexec_file_load() and all the associated code
compiles if CONFIG_KEXEC=y. But new syscall also compiles purgatory
code which currently uses gcc option -mcmodel=large. This option seems
to be available only gcc 4.4 onwards.
Hiding new functionality behind a new config option will not break
existing users of old gcc. Those who wish to enable new functionality
will require new gcc. Having said that, I am trying to figure out how
can I move away from using -mcmodel=large but that can take a while.
I think there are other advantages of introducing this new config
option. As this option will be enabled only on x86_64, other arches
don't have to compile generic kexec code which will never be used. This
new code selects CRYPTO=y and CRYPTO_SHA256=y. And all other arches had
to do this for CONFIG_KEXEC. Now with introduction of new config
option, we can remove crypto dependency from other arches.
Now CONFIG_KEXEC_FILE is available only on x86_64. So whereever I had
CONFIG_X86_64 defined, I got rid of that.
For CONFIG_KEXEC_FILE, instead of doing select CRYPTO=y, I changed it to
"depends on CRYPTO=y". This should be safer as "select" is not
recursive.
Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Cc: Eric Biederman <ebiederm@xmission.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Tested-by: Shaun Ruffell <sruffell@digium.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/arch/x86/Makefile b/arch/x86/Makefile
index c1aa368..c96bcec 100644
--- a/arch/x86/Makefile
+++ b/arch/x86/Makefile
@@ -184,11 +184,8 @@
$(Q)$(MAKE) $(build)=arch/x86/syscalls all
archprepare:
-ifeq ($(CONFIG_KEXEC),y)
-# Build only for 64bit. No loaders for 32bit yet.
- ifeq ($(CONFIG_X86_64),y)
+ifeq ($(CONFIG_KEXEC_FILE),y)
$(Q)$(MAKE) $(build)=arch/x86/purgatory arch/x86/purgatory/kexec-purgatory.c
- endif
endif
###