[coreboot-gerrit] Patch merged into coreboot/master: fd79562 romstage: add support for vboot firmware selection

the following patch was just integrated into master:
commit fd79562915bbdea93fc7b37e657856acf808e64f
Author: Aaron Durbin 
Date:   Fri Mar 1 17:12:26 2013 -0600

romstage: add support for vboot firmware selection

This patch implements support for vboot firmware selection. The vboot
    support is comprised of the following pieces:

1. vboot_loader.c - this file contains the entry point,
       vboot_verify_firmware(), for romstage to call in order to perform
       vboot selection. The loader sets up all the data for the wrapper
       to use.
    2. vboot_wrapper.c - this file contains the implementation calling the vboot
       API. It calls VbInit() and VbSelectFirmware() with the data supplied
       by the loader.

The vboot wrapper is compiled and linked as an rmodule and placed in
    cbfs as 'fallback/vboot'. It's loaded into memory and relocated just
    like the way ramstage would be. After being loaded the loader calls into
    wrapper. When the wrapper sees that a given piece of firmware has been
    selected it parses firmware component information for a predetermined
    number of components.

Vboot result information is passed to downstream users by way of the
    vboot_handoff structure. This structure lives in cbmem and contains
    the shared data, selected firmware, VbInitParams, and parsed firwmare
    components.

During ramstage there are only 2 changes:

1. Copy the shared vboot data from vboot_handoff to the chromeos acpi
       table.
    2. If a firmware selection was made in romstage the boot loader
       component is used for the payload.

Noteable Information:
    - no vboot path for S3.
    - assumes that all RW firmware contains a book keeping header for the
      components that comprise the signed firmware area.
    - As sanity check there is a limit to the number of firmware components
      contained in a signed firmware area. That's so that an errant value
      doesn't cause the size calculation to erroneously read memory it
      shouldn't.
    - RO normal path isn't supported. It's assumed that firmware will always
      load the verified RW on all boots but recovery.
    - If vboot requests memory to be cleared it is assumed that the boot
      loader will take care of that by looking at the out flags in
    VbInitParams.

Built and booted. Noted firmware select worked on an image with
    RW firmware support. Also checked that recovery mode worked as well
    by choosing the RO path.

Change-Id: I45de725c44ee5b766f866692a20881c42ee11fa8
    Signed-off-by: Aaron Durbin 
    Reviewed-on: http://review.coreboot.org/2854
    Tested-by: build bot (Jenkins)
    Reviewed-by: Ronald G. Minnich

Build-Tested: build bot (Jenkins) at Wed Mar 20 23:05:36 2013, giving +1
See http://review.coreboot.org/2854 for details.

-gerrit