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eeb77379e0
cr50 by default delays nvmem commits internally from the point of reset to accumulate change state. However, the factory process can put a board into dev mode through the recovery screen. This state is stored in the TPM's nvmem space. When the factory process is complete a disable_dev_request and battery_cutoff_request is performed. This leads to disabling the dev mode in TPM, but the battery is subsequently cut off so the nvmem contents never stick. Therefore, whenever antirollback_write_space_firmware() is called we know there was a change in secdata so request cr50 to immediately enable nvmem commits going forward. This allows state changes to happen immediately. The fallout from this is that when secdata is changed that current boot will take longer because every transaction that writes to TPM nvmem space will perform a write synchronously. All subsequent boots do not have that effect. It should also be noted that this approach to the implementation is a pretty severe layering violation. However, the current TPM APIs don't lend themselves well to extending commands or re-using code outside of the current routines which inherently assume all knowledge of every command (in conflict with vendor commands since those are vendor-specific by definition). BUG=b:35775104 BRANCH=reef TEST=Confirmed disablement of dev mode sticks in the presence of: crossystem disable_dev_request=1; crossystem battery_cutoff_request=1; reboot; Change-Id: I3395db9cbdfea45da1f5cb994c6570978593b944 Signed-off-by: Aaron Durbin <adurbin@chromium.org> Reviewed-on: https://review.coreboot.org/18681 Reviewed-by: Duncan Laurie <dlaurie@chromium.org> Tested-by: build bot (Jenkins) |
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| 3rdparty | ||
| configs | ||
| Documentation | ||
| payloads | ||
| src | ||
| util | ||
| .checkpatch.conf | ||
| .clang-format | ||
| .gitignore | ||
| .gitmodules | ||
| .gitreview | ||
| COPYING | ||
| gnat.adc | ||
| MAINTAINERS | ||
| Makefile | ||
| Makefile.inc | ||
| README | ||
| toolchain.inc | ||
------------------------------------------------------------------------------- coreboot README ------------------------------------------------------------------------------- coreboot is a Free Software project aimed at replacing the proprietary BIOS (firmware) found in most computers. coreboot performs a little bit of hardware initialization and then executes additional boot logic, called a payload. With the separation of hardware initialization and later boot logic, coreboot can scale from specialized applications that run directly firmware, run operating systems in flash, load custom bootloaders, or implement firmware standards, like PC BIOS services or UEFI. This allows for systems to only include the features necessary in the target application, reducing the amount of code and flash space required. coreboot was formerly known as LinuxBIOS. Payloads -------- After the basic initialization of the hardware has been performed, any desired "payload" can be started by coreboot. See http://www.coreboot.org/Payloads for a list of supported payloads. Supported Hardware ------------------ coreboot supports a wide range of chipsets, devices, and mainboards. For details please consult: * http://www.coreboot.org/Supported_Motherboards * http://www.coreboot.org/Supported_Chipsets_and_Devices Build Requirements ------------------ * make * gcc / g++ Because Linux distribution compilers tend to use lots of patches. coreboot does lots of "unusual" things in its build system, some of which break due to those patches, sometimes by gcc aborting, sometimes - and that's worse - by generating broken object code. Two options: use our toolchain (eg. make crosstools-i386) or enable the ANY_TOOLCHAIN Kconfig option if you're feeling lucky (no support in this case). * iasl (for targets with ACPI support) Optional: * doxygen (for generating/viewing documentation) * gdb (for better debugging facilities on some targets) * ncurses (for 'make menuconfig' and 'make nconfig') * flex and bison (for regenerating parsers) Building coreboot ----------------- Please consult http://www.coreboot.org/Build_HOWTO for details. Testing coreboot Without Modifying Your Hardware ------------------------------------------------ If you want to test coreboot without any risks before you really decide to use it on your hardware, you can use the QEMU system emulator to run coreboot virtually in QEMU. Please see http://www.coreboot.org/QEMU for details. Website and Mailing List ------------------------ Further details on the project, a FAQ, many HOWTOs, news, development guidelines and more can be found on the coreboot website: http://www.coreboot.org You can contact us directly on the coreboot mailing list: http://www.coreboot.org/Mailinglist Copyright and License --------------------- The copyright on coreboot is owned by quite a large number of individual developers and companies. Please check the individual source files for details. coreboot is licensed under the terms of the GNU General Public License (GPL). Some files are licensed under the "GPL (version 2, or any later version)", and some files are licensed under the "GPL, version 2". For some parts, which were derived from other projects, other (GPL-compatible) licenses may apply. Please check the individual source files for details. This makes the resulting coreboot images licensed under the GPL, version 2.