soc/intel: Backport SMRR locking support

Backport commit 0cded1f116 (soc/intel/tigerlake: Add SMRR Locking
support) to other client platforms. The SMRR MSRs are core-scoped on
Skylake and Ice Lake, at least. Older platforms do not support SMRR
locking, but now there's seven copies of the same file in the tree. A
follow-up will deduplicate smmrelocate.c files into common CPU code.

I cannot test Jasper Lake nor Elkhart Lake, but they should still work.
As per documentation I do not have access to, Elkhart Lake seems to
support SMRR locking. However, Jasper Lake documentation is unclear.

Tested on Purism Librem Mini v1 (WHL-U i7-8565U), still boots and SMRR
MSRs have the same value on all cores/threads (i7-8565U supports HT).

Change-Id: Icbee0985b04418e83cbf41b81f00934f5a663e30
Signed-off-by: Angel Pons <th3fanbus@gmail.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/50936
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Michael Niewöhner <foss@mniewoehner.de>
Reviewed-by: Tim Wawrzynczak <twawrzynczak@chromium.org>
Reviewed-by: Arthur Heymans <arthur@aheymans.xyz>
Reviewed-by: Nico Huber <nico.h@gmx.de>

1 files changed, 17 insertions, 0 deletions

diff --git a/src/soc/intel/skylake/smmrelocate.c b/src/soc/intel/skylake/smmrelocate.c
index 0cc42e23d9..4df90fd7ce 100644
--- a/src/soc/intel/skylake/smmrelocate.c
+++ b/src/soc/intel/skylake/smmrelocate.c
@@ -1,6 +1,7 @@
 /* SPDX-License-Identifier: GPL-2.0-only */
 
 #include <console/console.h>
+#include <cpu/intel/common/common.h>
 #include <cpu/intel/em64t101_save_state.h>
 #include <cpu/intel/smm_reloc.h>
 #include <cpu/x86/mp.h>
@@ -137,8 +138,24 @@ void smm_relocation_handler(int cpu, uintptr_t curr_smbase,
 	/* Make appropriate changes to the save state map. */
 	update_save_state(cpu, curr_smbase, staggered_smbase, relo_params);
 
+	/*
+	 * The SMRR MSRs are core-level registers, so if two threads that share
+	 * a core try to both set the lock bit (in the same physical register),
+	 * a #GP will be raised on the second write to that register (which is
+	 * exactly what the lock is supposed to do), therefore secondary threads
+	 * should exit here.
+	 */
+	if (intel_ht_sibling())
+		return;
+
 	/* Write SMRR MSRs based on indicated support. */
 	mtrr_cap = rdmsr(MTRR_CAP_MSR);
+
+	/* Set Lock bit if supported */
+	if (mtrr_cap.lo & SMRR_LOCK_SUPPORTED)
+		relo_params->smrr_mask.lo |= SMRR_PHYS_MASK_LOCK;
+
+	/* Write SMRRs if supported */
 	if (mtrr_cap.lo & SMRR_SUPPORTED)
 		write_smrr(relo_params);
 }