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What this change does: 1) Initialize limited page tables as soon as we jump into libpayload. Basically two ranges are initialized. One is for the BASE_ADDRESS and other is for the coreboot_tables. With page tables initialized and MMU enabled, we jump into code to parse coreboot tables. 2) Once coreboot tables are parsed and we have complete picture of the memory, we perform a complete page table initialzation and enable MMU and then jump to payload. Additionally, we also: 1) Initialize DMA memory on our own depending upon the memory map. It ensures that the DMA buffer is placed in 32-bit memory. CQ-DEPEND=CL:216826 BUG=chrome-os-partner:31634 BRANCH=None TEST=Compiles successfully and we are able to start execution of libpayload in EL2 and reach kernel login prompt Change-Id: I8a6203e465868bc2a3e5cc377e108f36cc58e2fa Signed-off-by: Patrick Georgi <pgeorgi@chromium.org> Original-Commit-Id: 7695bb7afe34ea460282125a0be440e8994b01e4 Original-Change-Id: Ie0f47b7759d4ac65a6920f7f2f7502b889afda6d Original-Signed-off-by: Furquan Shaikh <furquan@google.com> Original-Reviewed-on: https://chromium-review.googlesource.com/216824 Original-Reviewed-by: Aaron Durbin <adurbin@chromium.org> Original-Tested-by: Furquan Shaikh <furquan@chromium.org> Original-Commit-Queue: Furquan Shaikh <furquan@chromium.org> Reviewed-on: http://review.coreboot.org/8792 Tested-by: build bot (Jenkins) Reviewed-by: Stefan Reinauer <stefan.reinauer@coreboot.org> |
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.. | ||
arch | ||
bin | ||
configs | ||
crypto | ||
curses | ||
drivers | ||
gdb | ||
include | ||
libc | ||
libcbfs | ||
liblzma | ||
libpci | ||
sample | ||
tests | ||
util | ||
Config.in | ||
Doxyfile | ||
LICENSE_GPL | ||
LICENSES | ||
Makefile | ||
Makefile.inc | ||
README |
------------------------------------------------------------------------------- libpayload README ------------------------------------------------------------------------------- libpayload is a minimal library to support standalone payloads that can be booted with firmware like coreboot. It handles the setup code, and provides common C library symbols such as malloc() and printf(). Note: This is _not_ a standard library for use with an operating system, rather it's only useful for coreboot payload development! See http://coreboot.org for details on coreboot. Installation ------------ $ git clone http://review.coreboot.org/p/coreboot.git $ cd coreboot/payloads/libpayload $ make menuconfig $ make $ sudo make install (optional, will install into /opt per default) As libpayload is for 32bit x86 systems only, you might have to install the 32bit libgcc version, otherwise your payloads will fail to compile. On Debian systems you'd do 'apt-get install gcc-multilib' for example. Usage ----- Here's an example of a very simple payload (hello.c) and how to build it: #include <libpayload.h> int main(void) { printf("Hello, world!\n"); return 0; } Building the payload using the 'lpgcc' compiler wrapper: $ lpgcc -o hello.elf hello.c Please see the sample/ directory for details. Website and Mailing List ------------------------ The main website is http://www.coreboot.org/Libpayload. For additional information, patches, and discussions, please join the coreboot mailing list at http://coreboot.org/Mailinglist, where most libpayload developers are subscribed. Copyright and License --------------------- See LICENSES.