On Thu, Mar 15, 2007 at 11:17:26AM +0530, Vivek Goyal wrote: > On Thu, Mar 15, 2007 at 02:07:56PM +0900, Horms wrote: > > On Thu, Mar 15, 2007 at 10:25:36AM +0530, Vivek Goyal wrote: > > > On Thu, Mar 15, 2007 at 10:46:38AM +0900, Horms wrote: > > > > On Wed, Mar 14, 2007 at 05:00:09PM +0000, Ian Campbell wrote: > > > > > The specific case I am encountering is kdump under Xen with a 64 bit > > > > > hypervisor and 32 bit kernel/userspace. The dump created is a 64 bit > > > > > due > > > > > to the hypervisor but the dump kernel is 32 bit to match the domain 0 > > > > > kernel. > > > > > > > > > > It's possibly less likely to be useful in a purely native scenario > > > > > but I > > > > > see no reason to disallow it. > > > > > > > > For native Linux, would this cover the case where the pre-crash kernel > > > > is 64bit and the crashdump (post-crash) kernel is 32bit? > > > > > > > > > > I think so. Though I have never tried this. > > > > > > > > Signed-off-by: Ian Campbell <[EMAIL PROTECTED]> > > > > > > > > > > --- pristine-linux-2.6.18/include/asm-i386/elf.h 2006-09-20 > > > > > 04:42:06.000000000 +0100 > > > > > +++ linux-2.6.18-xen/include/asm-i386/elf.h 2007-03-14 > > > > > 16:42:30.000000000 +0000 > > > > > @@ -36,7 +36,7 @@ > > > > > * This is used to ensure we don't load something for the wrong > > > > > architecture. > > > > > */ > > > > > #define elf_check_arch(x) \ > > > > > - (((x)->e_machine == EM_386) || ((x)->e_machine == EM_486)) > > > > > + (((x)->e_machine == EM_386) || ((x)->e_machine == EM_486) || > > > > > ((x)->e_machine == EM_X86_64)) > > > > > > But I think changing this macro might run into issues. It is being used at > > > few places in kernel, for example while loading module. This will > > > essentially > > > mean that we allow loading 64bit x86_64 modules on 32bit i386 systems? > > > > > > Similarly, load_elf_interp() is using it, again will we allow loading a > > > interp written for X86_64 on a 32bit i386 machine? > > > > > > Should we create a separate macro something like elf_check_allowed_arch(), > > > to take care of such corner cases? > > > > That sounds reasonable to me. Though perhaps it could just be > > kexec_elf_check_arch() for now, as I don't think there are any > > other consumers of it. > > Kexec will also not allow loading an x86_64 kernel on a 32bit machine. > So how about something like vmcore_elf_allowed_cross_arch()? Vmcore code > can continue to check elf_check_arch() and if that fails it can invoke > vmcore_elf_allowed_cross_arch() to find out what cross arch are allowed > for vmcore.
That sounds a little messy, though perhaps it is a good solution anyway. -- Horms H: http://www.vergenet.net/~horms/ W: http://www.valinux.co.jp/en/ - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
