Implementation of Region API

At present reading data from storage in Vboot is a little fragmented. For
the firmware image, we expect the boot loader to handle this. For the disk
we have a block-level API. For the GBB (which also sits in the firmware
image) we expect the entire thing to be read before Vboot is called.

Add the concept of a region, and an API to read from a region. At present,
and most pressing, is reading from a GBB region. In the future this could
be extended to other parts of the firmware or even the disk.

Move all access to the GBB into this API so that the boot loader can provide
either a GBB region in one large contiguous chunk, or a function to deal with
read requests from vboot.

The call to VbExRegionRead() is behind a flag since not all boot loaders
support it yet.

The main change for boot loaders which don't support this new API is that
vboot will do more behind the scenes. For example, it will allocate memory
for chunks of data that it reads from the GBB, rather than just accessing it
directly. This approach is considerably simpler than trying to pass char **
everywhere and have vboot decide whether something needs to be allocated or

The tests are updated, mainly to include setting up a GBB structure
accessible from VbCommonParams, which is now required by the firmware and
kernel functions. In normal operation this is set up at the start of
VbLoadFIrmware() and VbSelectAndLoadKernel() but for tests which call
children of these functions directly, the GBB structure must be set up
manually by the test.

FEATURES=test sudo -E  emerge vboot_reference

Change-Id: I2c19e9dc2ed602d0642bbf4f7d27f79fe9fad873
Signed-off-by: Simon Glass <>
Reviewed-by: Randall Spangler <>
31 files changed