[PATCH] uml: allow building as 32-bit binary on 64bit host
This patch makes the command:
make ARCH=um SUBARCH=i386
work on x86_64 hosts (with support for building 32-bit binaries). This is
especially needed since 64-bit UMLs don't support 32-bit emulation for guest
binaries, currently. This has been tested in all possible cases and works.
Only exception is that I've built but not tested a 64-bit binary, because I
hadn't a 64-bit filesystem available.
Signed-off-by: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Cc: Jeff Dike <jdike@addtoit.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/arch/um/Makefile-i386 b/arch/um/Makefile-i386
index 3010590..93d0818 100644
--- a/arch/um/Makefile-i386
+++ b/arch/um/Makefile-i386
@@ -1,4 +1,4 @@
-SUBARCH_CORE := arch/um/sys-i386/ arch/i386/crypto/
+core-y += arch/um/sys-i386/ arch/i386/crypto/
TOP_ADDR := $(CONFIG_TOP_ADDR)
@@ -8,21 +8,32 @@
endif
endif
+LDFLAGS += -m elf_i386
+ELF_ARCH := $(SUBARCH)
+ELF_FORMAT := elf32-$(SUBARCH)
+OBJCOPYFLAGS := -O binary -R .note -R .comment -S
+
+ifeq ("$(origin SUBARCH)", "command line")
+ifneq ("$(shell uname -m | sed -e s/i.86/i386/)", "$(SUBARCH)")
+CFLAGS += $(call cc-option,-m32)
+USER_CFLAGS += $(call cc-option,-m32)
+HOSTCFLAGS += $(call cc-option,-m32)
+HOSTLDFLAGS += $(call cc-option,-m32)
+AFLAGS += $(call cc-option,-m32)
+LINK-y += $(call cc-option,-m32)
+UML_OBJCOPYFLAGS += -F $(ELF_FORMAT)
+
+export LDFLAGS HOSTCFLAGS HOSTLDFLAGS UML_OBJCOPYFLAGS
+endif
+endif
+
CFLAGS += -U__$(SUBARCH)__ -U$(SUBARCH) $(STUB_CFLAGS)
-ARCH_USER_CFLAGS :=
ifneq ($(CONFIG_GPROF),y)
ARCH_CFLAGS += -DUM_FASTCALL
endif
-ELF_ARCH := $(SUBARCH)
-ELF_FORMAT := elf32-$(SUBARCH)
-
-OBJCOPYFLAGS := -O binary -R .note -R .comment -S
-
-SYS_UTIL_DIR := $(ARCH_DIR)/sys-i386/util
-
-SYS_HEADERS := $(SYS_DIR)/sc.h $(SYS_DIR)/thread.h
+SYS_HEADERS := $(SYS_DIR)/sc.h $(SYS_DIR)/thread.h
prepare: $(SYS_HEADERS)