xref: /openbmc/u-boot/doc/usage/measured_boot.rst (revision a773e935)
1*a773e935SEddie James.. SPDX-License-Identifier: GPL-2.0+
2*a773e935SEddie James
3*a773e935SEddie JamesMeasured Boot
4*a773e935SEddie James=====================
5*a773e935SEddie James
6*a773e935SEddie JamesU-Boot can perform a measured boot, the process of hashing various components
7*a773e935SEddie Jamesof the boot process, extending the results in the TPM and logging the
8*a773e935SEddie Jamescomponent's measurement in memory for the operating system to consume.
9*a773e935SEddie James
10*a773e935SEddie JamesRequirements
11*a773e935SEddie James---------------------
12*a773e935SEddie James
13*a773e935SEddie James* A hardware TPM 2.0 supported by the U-Boot drivers
14*a773e935SEddie James* CONFIG_TPM=y
15*a773e935SEddie James* CONFIG_MEASURED_BOOT=y
16*a773e935SEddie James* Device-tree configuration of the TPM device to specify the memory area
17*a773e935SEddie James  for event logging. The TPM device node must either contain a phandle to
18*a773e935SEddie James  a reserved memory region or "linux,sml-base" and "linux,sml-size"
19*a773e935SEddie James  indicating the address and size of the memory region. An example can be
20*a773e935SEddie James  found in arch/sandbox/dts/test.dts
21*a773e935SEddie James* The operating system must also be configured to use the memory regions
22*a773e935SEddie James  specified in the U-Boot device-tree in order to make use of the event
23*a773e935SEddie James  log.
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