On Thu, Sep 25, 2008 at 12:51:47PM -0600, Jordan Crouse wrote: > This is a simple patch to parse and read the multiboot table > in libpayload. It doesn't do much more then read the memory > map for now, but the important thing is that we are storing off > %eax and %ebx in the init code and using it when we need it.
Nice! > The next step is probably an API where upon a multiboot aware > payload could insert new things into the table (say, the drive > structure, or the cmdline or other interesting information), and then > pass it to a child payload. If you want to preserve the table for future use, I recommend that you copy it early in the code. Per spec the loader doesn't make any promises on its location (other than not overwriting your code with it, of course). > I'm not sure what else we would need to do to libpayload so that > grub will load the payloads, but I'm sure Robert will enlighten us. You also need a Multiboot header in the resulting image. It has to be 32bit-aligned and in the first 8k. For what your patch does, the following should suffice: 0x1BADB002 (magic) 0x00000002 (flag for memory info) (-0x1BADB002 -0x00000002) (checksum) For details see http://www.gnu.org/software/grub/manual/multiboot/html_node/Header-layout.html#Header-layout -- Robert Millan The DRM opt-in fallacy: "Your data belongs to us. We will decide when (and how) you may access your data; but nobody's threatening your freedom: we still allow you to remove your data and not access it at all." -- coreboot mailing list: [email protected] http://www.coreboot.org/mailman/listinfo/coreboot
