On Monday 30 March 2009 23:35:52 phcoder wrote: > Pavel Roskin wrote: > > On Sat, 2009-03-28 at 13:53 +0100, Robert Millan wrote: > >>> Here's a patch to rename `linux' to `linux16' and build the 32-bit > >>> loader as simply `linux'. > >> > >> Committed. > > > > Just for your information. With the old loader, booting an x86_64 > > kernel in qemu emulating i386 would result in a kernel message: > > > > "This kernel requires an x86-64 CPU but only detected an i686 CPU > > Unable to boot - please use a kernel appropriate for your CPU" > > > > With the new loader, the kernel hands without showing any messages. It > > can be a kernel bug. Linux 2.6.29, current GRUB. > > I confirm. I suppose that this check and message is bypassed with 32-bit > loading mode. IMO grub2 should provide an equivlent of this check. We > already have cpuid code. Does anyone know how to determine if kernel is > i386 or amd64?
I don't know any reliable way. Some candidates: - The ramdisk max value. On 32-bit, initrd may not be loaded onto over 2GB. This is hard to change in Linux, so we can expect that this will not change. On 64-bit, currently, the max is 4GB-1. It is likely that this value will not change, but who knows. - The long mode panic message. This exists only for x86_64. But the message might change some day. - Otherwise, we could probe some opcodes and see if 64-bit opcodes are used. This would be error-prone. After all, the best way might be to just ask Linux developers to add a new flag. Regards, Okuji _______________________________________________ Grub-devel mailing list Grub-devel@gnu.org http://lists.gnu.org/mailman/listinfo/grub-devel
