On 13/11/11 13:31, Gabe Black wrote: > From: Gabe Black <gabebl...@google.com> > > There are two blobs embedded into the u-boot image which are linked to run > at an address which is different from where they actually end up in the > ROM, one called "realmode" and one called "bios". There are realmode_setup > and bios_setup functions which prepare those blobs by copying them into the > location they're supposed to run from, among other things. > > During u-boot relocation from ROM to RAM, the text and a few data segments > are copied over. The realmode and bios sections are not copied, and so the > only place they can be read from is their original location in the ROM. > Looking specifically at the bios blob, there are symbols defined in the > linker script called __bios_start and __bios_size which are defined to be > the start and size of the blob in the ROM. > > In the bios_setup function, there seem to be two mistakes happening. First, > the offset from ROM to RAM is being added to __bios_start which implies that > this code expects to use the copy moved to RAM. No such copy is made, so > that's wrong. More subtly, when u-boot relocates itself, it goes through > all of the relocations stored in .rel.dyn and fixes them up. This has the > effect of transforming the __bios_start reference in bios_setup so that it > refers to the version in RAM (if one existed) instead of the one in ROM. To > correct for that, the offset actually needs to be subtracted out again to > translate the address back into the ROM. > > The net effect is that for both blobs, a + needs to be changed to a -. > > Signed-off-by: Gabe Black <gabebl...@chromium.org> > ---
Applied to u-boot-x86/master Thanks, Graeme _______________________________________________ U-Boot mailing list U-Boot@lists.denx.de http://lists.denx.de/mailman/listinfo/u-boot
