dbadb1dd63
The current default memcpy first copies single bytes to align the amount, then copies the rest as full words. In practice, the start of a buffer is much more likely to be word-aligned then the end, and aligned word access are usually more efficient. This patch reorders those accesses to first copy as many full words as possible and then finish the rest with byte accesses to optimize this common case. This fixes a data abort when using USB on ARM without CONFIG_GPL. Due to some limitations of how DMA memory is set up in coreboot on ARM, it currently does not support unaligned accesses. (This could be fixed with a more complicated patch, but it's usually not an issue... unless, of course, your memcpy happens to be braindead). Also add word-aligned accesses to memset and memcmp while I'm at it, and make memcmp's return value standard's compliant. BUG=chrome-os-partner:24957 TEST=Manual Original-Change-Id: I2a7bcb35626a05a9a43fcfd99eb958b485d7622a Original-Signed-off-by: Julius Werner <jwerner@chromium.org> Original-Reviewed-on: https://chromium-review.googlesource.com/203547 Original-Reviewed-by: Stefan Reinauer <reinauer@chromium.org> Original-Reviewed-by: David Hendricks <dhendrix@chromium.org> (cherry picked from commit 05a64d2e107e1675cc3442e6dabe14a341e55673) Signed-off-by: Marc Jones <marc.jones@se-eng.com> Change-Id: I0030ca8a203c97587b0da31a0a5e9e11b0be050f Reviewed-on: http://review.coreboot.org/8126 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 | ||
LICENSES | ||
LICENSE_GPL | ||
Makefile | ||
Makefile.inc | ||
README |
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.