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coreboot for the Switch
Remember the XN bit? The one we had so much fun with on Nyan (LPAE) because not setting it allows random instruction prefetches to device memory that hang the system every few thousand boots? Thankfully, we had always been setting it in the non-LPAE MMU code already... "When the XN bit is 1, a Permission fault is generated if the processor attempts to execute an instruction fetched from the corresponding memory region. However, when using the Short-descriptor translation table format, the fault is generated only if the access is to memory in the Client domain, see Domains[...]" - ARM A.R.M. section B3.7.2 Oops. This patch changes our Domain Access Control Register (DACR) to set domain 0 (the only one we are using) to Client. This means that access permissions (AP[2:0] bits) become enforced, but they are already set to full access (0b011). It also means that non-LPAE systems will not be allowed to execute from DCACHE_OFF memory with enabled MMU anymore. As far as I can see, Veyron_Pinky has been the only board that does that. BUG=chrome-os-partner:32118 TEST=Booted Veyron_Pinky with MMU in the bootblock, saw hangs that look like spurious prefetches and confirmed that this patch fixes them. Change-Id: I81c00743f938924a5dc8825389fe512a069b77db Signed-off-by: Patrick Georgi <pgeorgi@chromium.org> Original-Commit-Id: cbc96db296a41ae700371a8515a1179c142f58e7 Original-Change-Id: I30676a5bfe12d516e5f910f51ee6854f6e5be557 Original-Signed-off-by: Julius Werner <jwerner@chromium.org> Original-Reviewed-on: https://chromium-review.googlesource.com/223783 Original-Reviewed-by: Aaron Durbin <adurbin@chromium.org> Reviewed-on: http://review.coreboot.org/9343 Tested-by: build bot (Jenkins) Reviewed-by: Stefan Reinauer <stefan.reinauer@coreboot.org> |
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documentation | ||
payloads | ||
src | ||
util | ||
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.gitmodules | ||
.gitreview | ||
COPYING | ||
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 ------------------ * gcc / g++ * make Optional: * doxygen (for generating/viewing documentation) * iasl (for targets with ACPI support) * gdb (for better debugging facilities on some targets) * ncurses (for 'make menuconfig') * 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.