the following patch was just integrated into master: commit ed3743123e4f832be6761a9b550cab5cc8a3f934 Author: Kyösti Mälkki kyosti.malkki@gmail.com Date: Tue Feb 14 10:39:17 2012 +0200
Add support for RAM-less multi-processor init
For a hyper-threading processor, enabling cache requires that both the BSP and AP CPU clear CR0.CD (Cache Disable) bit. For a Cache-As-Ram implementation, partial multi-processor initialisation precedes raminit and AP CPUs' 16bit entry must be run from ROM.
The AP CPU can only start execute real-mode code at a 4kB aligned address below 1MB. The protected mode entry code for AP is identical with the BSP code, which is already located at the top of bootblock. This patch takes the simplest approach and aligns the bootblock 16 bit entry at highest possible 4kB boundary below 1MB.
The symbol ap_sipi_vector is tested to match CONFIG_AP_SIPI_VECTOR used by the CAR code in romstage. Adress is not expected to ever change, but if it does, link will fail.
Change-Id: I82e4edbf208c9ba863f51a64e50cd92871c528ef Signed-off-by: Kyösti Mälkki kyosti.malkki@gmail.com
See http://review.coreboot.org/454 for details.
-gerrit