haswell: enable caching before SMM initialization

The SMM handler resides in the TSEG region which is far above
CONFIG_RAM_TOP (which is the highest cacheable address) before
MTRRs are setup. This means that calling initialize_cpus() before
performing MTRR setup on the BSP means the SMM handler is copied
using uncacheable accesses.

Improve the SMM handler setup path by enabling performing MTRR setup on
for the BSP before the call to initialize_cpus(). In order to do this
the haswell_init() function was split into 2 paths: BSP & AP paths.
There is a cpu_common_init() that both call to perform similar
functionality. The BSP path in haswell_init() then starts the APs using
intel_cores_init(). The AP path in haswell_init() loads microcode and
sets up MTRRs.

This split will be leveraged for future support of bringing up APs in
parallel as well as adhering to the Haswell MP initialization
requirements.

Change-Id: Id8e17af149e68d708f3d4765e38b1c61f7ebb470
Signed-off-by: Aaron Durbin <adurbin@chromium.org>
Reviewed-on: http://review.coreboot.org/2746
Tested-by: build bot (Jenkins)
Reviewed-by: Ronald G. Minnich <rminnich@gmail.com>

1 files changed, 1 insertions, 10 deletions

diff --git a/src/northbridge/intel/haswell/northbridge.c b/src/northbridge/intel/haswell/northbridge.c
index 90c47a7844..d20a40b53c 100644
--- a/src/northbridge/intel/haswell/northbridge.c
+++ b/src/northbridge/intel/haswell/northbridge.c
@@ -594,16 +594,7 @@ static const struct pci_driver mc_driver_hsw_ult __pci_driver = {
 
 static void cpu_bus_init(device_t dev)
 {
-	/*
-	 * This calls into the gerneic initialize_cpus() which attempts to
-	 * start APs on the APIC bus in the devicetree.  No APs get started
-	 * because there is only the BSP and placeholder (disabled) in the
-	 * devicetree. initialize_cpus() also does SMM initialization by way
-	 * of smm_init(). It will eventually call cpu_initialize(0) which calls
-	 * dev_ops->init(). For Haswell the dev_ops->init() starts up the APs
-	 * by way of intel_cores_init().
-	 */
-	initialize_cpus(dev->link_list);
+	bsp_init_and_start_aps(dev->link_list);
 }
 
 static void cpu_bus_noop(device_t dev)