[PATCH] uml: start cross-build support : mk_user_constants

Beginning of cross-build fixes.  Instead of expecting that mk_user_constants
(compiled and executed on the build box) will see the sizeof, etc.  for target
box, we do what every architecture already does for asm-offsets.  Namely, have
user-offsets.c compiled *for* *target* into user-offsets.s and sed it into the
header with relevant constants.  We don't need to reinvent any wheels - all
tools are already there.

This patch deals with mk_user_constants.  It doesn't assume any relationship
between target and build environment anymore - we pick all defines we need
from user-offsets.h.  Later patches will deal with the rest of mk_...  helpers
in the same way.

Signed-off-by: Al Viro <viro@parcelfarce.linux.theplanet.co.uk>
Signed-off-by: Jeff Dike <jdike@addtoit.com>
Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

2 files changed, 3 insertions, 9 deletions

diff --git a/arch/um/os-Linux/util/Makefile b/arch/um/os-Linux/util/Makefile
index fb00ddf969bd..9778aed0c314 100644
--- a/arch/um/os-Linux/util/Makefile
+++ b/arch/um/os-Linux/util/Makefile
@@ -1,4 +1,4 @@
 hostprogs-y             := mk_user_constants
 always                  := $(hostprogs-y)
 
-mk_user_constants-objs  := mk_user_constants.o
+HOSTCFLAGS_mk_user_constants.o := -I$(objtree)/arch/um
diff --git a/arch/um/os-Linux/util/mk_user_constants.c b/arch/um/os-Linux/util/mk_user_constants.c
index 0933518aa8bd..4838f30eecf0 100644
--- a/arch/um/os-Linux/util/mk_user_constants.c
+++ b/arch/um/os-Linux/util/mk_user_constants.c
@@ -1,11 +1,5 @@
 #include <stdio.h>
-#include <asm/types.h>
-/* For some reason, x86_64 nowhere defines u64 and u32, even though they're
- * used throughout the headers.
- */
-typedef __u64 u64;
-typedef __u32 u32;
-#include <asm/user.h>
+#include <user-offsets.h>
 
 int main(int argc, char **argv)
 {
@@ -20,7 +14,7 @@ int main(int argc, char **argv)
    * x86_64 (216 vs 168 bytes).  user_regs_struct is the correct size on
    * both x86_64 and i386.
    */
-  printf("#define UM_FRAME_SIZE %d\n", (int) sizeof(struct user_regs_struct));
+  printf("#define UM_FRAME_SIZE %d\n", __UM_FRAME_SIZE);
 
   printf("\n");
   printf("#endif\n");