x32: Warn and disable rather than error if binutils too old
If X32 is enabled in .config, but the binutils can't build it, issue a
warning and disable the feature rather than erroring out.
In order to support this, have CONFIG_X86_X32 be the option set in
Kconfig, and CONFIG_X86_X32_ABI be the option set by the Makefile when
it is enabled and binutils has been found to be functional.
Requested-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Cc: H. J. Lu <hjl.tools@gmail.com>
Link: http://lkml.kernel.org/r/1329696488-16970-1-git-send-email-hpa@zytor.com
diff --git a/arch/x86/Makefile b/arch/x86/Makefile
index 209ba12..31bb1eb 100644
--- a/arch/x86/Makefile
+++ b/arch/x86/Makefile
@@ -82,6 +82,22 @@
endif
endif
+ifdef CONFIG_X86_X32
+ x32_ld_ok := $(call try-run,\
+ /bin/echo -e '1: .quad 1b' | \
+ $(CC) $(KBUILD_AFLAGS) -c -xassembler -o "$$TMP" - && \
+ $(OBJCOPY) -O elf32-x86-64 "$$TMP" "$$TMPO" && \
+ $(LD) -m elf32_x86_64 "$$TMPO" -o "$$TMP",y,n)
+ ifeq ($(x32_ld_ok),y)
+ CONFIG_X86_X32_ABI := y
+ KBUILD_AFLAGS += -DCONFIG_X86_X32_ABI
+ KBUILD_CFLAGS += -DCONFIG_X86_X32_ABI
+ else
+ $(warning CONFIG_X86_X32 enabled but no binutils support)
+ endif
+endif
+export CONFIG_X86_X32_ABI
+
# Don't unroll struct assignments with kmemcheck enabled
ifeq ($(CONFIG_KMEMCHECK),y)
KBUILD_CFLAGS += $(call cc-option,-fno-builtin-memcpy)