From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dan Kegel Date: Mon, 02 Feb 2004 01:19:08 +0000 Subject: offsets.h and 32 -> 64 bit cross-compiling Message-Id: <401DA58C.8070105@kegel.com> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: linux-ia64@vger.kernel.org I recently updated my toolchain build script (http://kegel.com/crosstool) to use linux-2.4.21 headers instead of linux-2.4.20, and can no longer generate an x86 -> ia64 cross toolchain. The new kernel source tree no longer has asm-ia64/offsets.h, since that is now generated from other .h files at 'make dep' time. Keith Owens noticed back in Sept '03 that this had a chicken-and-egg problem when cross-compiling, and posted http://www.gelato.unsw.edu.au/linux-ia64/0309/6667.html to fix that. Sadly, that fix seems to be insufficient. On my x86 build machine, 'make ARCH=ia64 dep' for linux-2.4.21 now fails with errors like gcc -g -O2 -Wall -D__KERNEL__ -I/cross/linux-2.4.21/include -DKBUILD_BASENAME= print_offsets.c -o print_offsets In file included ... from print_offsets.c:17: /cross/linux-2.4.21/include/asm/page.h:75: warning: width of `off' exceeds its type In file included ... from print_offsets.c:17: /cross/linux-2.4.21/include/asm/byteorder.h: In function `__ia64_swab32': /cross/linux-2.4.21/include/asm/byteorder.h:23: warning: right shift count >= width of type (I suspect this has not changed in newer 2.4 kernels.) Note that plain old gcc is used to compile this file, since it has to generate an executable that can run on the build machine. This doesn't seem to work when the build machine and the target architecture have different bit widths! Looking at the first error, page.h uses 'unsigned long' to indicate a 64 bit integer. That could be fixed by using __u64 or uint64_t, assuming we change 's definition of __u64 to work when cross-compiling. To check whether the fix is complete, one would compare offsets.h generated by a cross-compile run with one generated by a native run. Has anyone looked at fixing this yet? I'm going to drop back to building with linux-2.4.20 headers or something for a while, but it'd be nice to have this actually work sometime, and I'm willing to do the work if nobody else has yet. Thanks, Dan