On Mon, Nov 19, 2012 at 3:13 PM, H. Peter Anvin <h...@zytor.com> wrote: > On 11/19/2012 02:53 PM, Yinghai Lu wrote: >> >> any other field, in header struct field that we can use to tell >> bzImage could be used that >> 0x200 directly? >> >> hardware_subarch? >> > > There isn't one... this dates back all the way to the original x86-64 > kernels. > > Are you asking if we can tell this is a 64-bit kernel (as opposed to a > 32-bit kernel, which obviously doesn't have a 64-bit entry point)? > Unfortunately there isn't an intentional one that I know of. There > might be an accidental such indicator, but we'd have to go back to look > at 8+ years of kernels. We can't even rely on a jmp instruction at the > address...
So we could add one field to tell that bzImage could be used with 64bit? current in this patchset, I added 0268/4 2.12+ ext_ramdisk_image ramdisk_image 32 bits 026C/4 2.12+ ext_ramdisk_size ramdisk_size high 32 bits 0270/4 2.12+ code64_start_offset 64bit start offset for bzImage 0274/4 2.12+ ext_cmd_line_ptr cmd_line_ptr high 32 bits so you don't like code64_start_offset. how about other three? can we use bits 31 of hardware_subarch to tell it is bzImage for x86_64? Thanks Yinghai -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
