soc/intel/apl: Rework on CPU privilege level implementation

This patch migrates common code API into SoC specific implementation
to drop CPU privilege level as the MSR is not consistent across
platforms.

For example: On APL/GLK, it's MSR 0x120 and CNL onwards it's MSR 0x151.

Also, include `soc/msr.h` in cpu.h to fix the compilation issue.

Signed-off-by: Subrata Banik <subratabanik@google.com>
Change-Id: I0b6f39509cc5457089cc15f28956833c36b567ad
Reviewed-on: https://review.coreboot.org/c/coreboot/+/60898
Reviewed-by: EricR Lai <ericr_lai@compal.corp-partner.google.com>
Reviewed-by: Nico Huber <nico.h@gmx.de>
Reviewed-by: Angel Pons <th3fanbus@gmail.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

3 files changed, 16 insertions, 1 deletions

diff --git a/src/soc/intel/apollolake/chip.c b/src/soc/intel/apollolake/chip.c
index 651bd8418c..98844a52fd 100644
--- a/src/soc/intel/apollolake/chip.c
+++ b/src/soc/intel/apollolake/chip.c
@@ -28,6 +28,7 @@
 #include <soc/intel/common/vbt.h>
 #include <soc/iomap.h>
 #include <soc/itss.h>
+#include <soc/msr.h>
 #include <soc/pci_devs.h>
 #include <soc/pm.h>
 #include <soc/systemagent.h>
@@ -702,10 +703,19 @@ struct chip_operations soc_intel_apollolake_ops = {
 	.final = &soc_final
 };
 
+static void soc_enable_untrusted_mode(void *unused)
+{
+	/*
+	 * Set Bit 6 (ENABLE_IA_UNTRUSTED_MODE) of MSR 0x120
+	 * UCODE_PCR_POWER_MISC MSR to enter IA Untrusted Mode.
+	 */
+	msr_set(MSR_POWER_MISC, ENABLE_IA_UNTRUSTED);
+}
+
 static void drop_privilege_all(void)
 {
 	/* Drop privilege level on all the CPUs */
-	if (mp_run_on_all_cpus(&cpu_enable_untrusted_mode, NULL) != CB_SUCCESS)
+	if (mp_run_on_all_cpus(&soc_enable_untrusted_mode, NULL) != CB_SUCCESS)
 		printk(BIOS_ERR, "failed to enable untrusted mode\n");
 }
 
diff --git a/src/soc/intel/apollolake/include/soc/cpu.h b/src/soc/intel/apollolake/include/soc/cpu.h
index 38b830a16f..3157952455 100644
--- a/src/soc/intel/apollolake/include/soc/cpu.h
+++ b/src/soc/intel/apollolake/include/soc/cpu.h
@@ -5,6 +5,7 @@
 
 #include <cpu/x86/msr.h>
 #include <intelblocks/msr.h>
+#include <soc/msr.h>
 
 struct device;
 void apollolake_init_cpus(struct device *dev);
diff --git a/src/soc/intel/apollolake/include/soc/msr.h b/src/soc/intel/apollolake/include/soc/msr.h
index e35c8814eb..97c67ddc21 100644
--- a/src/soc/intel/apollolake/include/soc/msr.h
+++ b/src/soc/intel/apollolake/include/soc/msr.h
@@ -5,4 +5,8 @@
 
 #include <intelblocks/msr.h>
 
+#define MSR_POWER_MISC		0x120
+#define  ENABLE_IA_UNTRUSTED	(1 << 6)
+#define  FLUSH_DL1_L2		(1 << 8)
+
 #endif