the following patch was just integrated into master: commit dbadb1dd634c8c9419215ade0666a7fb69a4447b Author: Julius Werner jwerner@chromium.org Date: Thu Jun 12 10:28:57 2014 -0700
libpayload: Reorder default memcpy, speed up memset and memcmp
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
See http://review.coreboot.org/8126 for details.
-gerrit