the following patch was just integrated into master: commit a3b2c440baca27f9275b2e4bb7cb591c565fc08d Author: Duncan Laurie dlaurie@chromium.org Date: Tue Jan 17 09:03:11 2012 -0800
Prepare the BIOS data areas before device init.
Since we do not run option roms in normal mode nothing was initializing the BDA/EBDA and yet Linux depends very much on it having sane values here. For the most part the kernel tries to work around this not being initialized, but every once in awhile (1/300 boots or so) it would end up reading something that looked sane from BDA but was not and then it would panic.
In this change the EBDA is unconditionally setup before devices are initialized. I'm not set on the location in dev_initialize() but there does not seem to be another place to hook it in so that it runs just once for ALL platforms regardless of whether they use option roms or not. (possibly hardwaremain?)
The EBDA setup code has been moved into its own location in arch/x86/lib/ebda.c so it can be compiled in even if the option rom code is not.
The low memory size is still set to 1MB which is enough to make linux happy without having to hook into each mainboard to get a more appropriate value. The setup_ebda() function takes inputs so it could be changed for a mainboard if needed.
OLD/BROKEN would read garbage. Examples from different boots: ebda_addr=0x75e80 lowmem=0x1553400 ebda_addr=0x5e080 lowmem=0x3e51400 ebda_addr=0x7aa80 lowmem=0x2f8a800
NEW/FIXED now reads consistent values: ebda_addr=0xf6000 lowmem=0x100000
Change-Id: I6cb79f0e3e43cc65f7e5fe98b6cad1a557ccd949 Signed-off-by: Duncan Laurie dlaurie@google.com
Build-Tested: build bot (Jenkins) at Fri Mar 30 12:26:50 2012, giving +1 See http://review.coreboot.org/769 for details.
-gerrit