Fixes: #3 Fixed: #8 Signed-off-by: Daniel Thompson daniel.thompson@linaro.org ---
Notes: This patch tries to capture contributions from a long a varied discussion. I hope I haven't missed anything major.
Thanks to all the contributors to this topic so far!
source/ebbr.rst | 47 +++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 47 insertions(+)
diff --git a/source/ebbr.rst b/source/ebbr.rst index 40f03f173bd9..30a9c6ac2666 100644 --- a/source/ebbr.rst +++ b/source/ebbr.rst @@ -185,6 +185,53 @@ System Volume Format --------------------
The system firmware must support GPT partitioning. +It may optionally also support MBR partitioning. + +On systems where the system firmware binaries reside on the System Volume then +the System Volume must be pre-configured with a partition table and include +protective partitions to reduce risk of accidental destruction of the system +firmware. + +All pre-configured partition tables must use GPT partitioning unless +some immutable feature of the platform (such as a mask programmed boot ROM) +makes this impossible; on such platforms MBR partitioning may be +used as an alternative. + +GPT partitioning +^^^^^^^^^^^^^^^^ + +Protective partitions should have the Platform Required Attribute Flag set +unless some immutable feature of the platform makes this impossible. + +It is recommended that automatic system disk partitioning utilities +preserve Platform Required partitions as is, and that manual disk +partitioning utilities provide warnings and/or other safe guards to +reduce risk of accidental removal. + +It is recommended that an implementer on a platform where Platform Required +cannot be set contribute a list of Partition type GUIDs for protective +partitions to the table below. It is further recommended that disk partitioning +utilities treat such partitions in the same manner as those with the Platform +Required Attribute Flag set. + ++--------------------------------------+---------------------------------------+ +| Partition type GUID | Comment | ++======================================+=======================================+ +| 00000000-0000-0000-0000-000000000000 | Unused entry (example; do not honour) | ++--------------------------------------+---------------------------------------+ + +MBR partitioning +^^^^^^^^^^^^^^^^ + +Protective partitions should have a partition type of 0xF8 unless some +immutable feature of the platform makes this impossible. + +It is recommended that disk partitioning utilities treat such +partitions in the same manner as GPT partitions with the Platform +Required Attribute Flag set. + +It is strongly recommended that protective partitions with a type other +than 0xF8 be placed within 1MB of the start of the disk.
UEFI Boot Services ==================