soc/intel/common/cpu: Use SoC overrides to get CPU privilege level

This patch implements a SoC overrides to check CPU privilege level
as the MSR is not consistent across platforms.

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

BUG=b:211573253, b:211950520

Signed-off-by: Subrata Banik <subratabanik@google.com>
Change-Id: I515f0a3548bc5d6250e30f963d46f28f3c1b90b3
Reviewed-on: https://review.coreboot.org/c/coreboot/+/60900
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Angel Pons <th3fanbus@gmail.com>

1 files changed, 9 insertions, 0 deletions

diff --git a/src/soc/intel/common/block/include/intelblocks/cpulib.h b/src/soc/intel/common/block/include/intelblocks/cpulib.h
index 3ce80b27db..b9c3ab70c3 100644
--- a/src/soc/intel/common/block/include/intelblocks/cpulib.h
+++ b/src/soc/intel/common/block/include/intelblocks/cpulib.h
@@ -112,6 +112,15 @@ void cpu_burst_mode(bool burst_mode_status);
 void cpu_set_eist(bool eist_status);
 
 /*
+ * SoC specific implementation:
+ *
+ * Check CPU security level using ENABLE_IA_UNTRUSTED_MODE of CPU MSR.
+ * If bit is set, meaning CPU has dropped its security level by entering
+ * into `untrusted mode`. Otherwise, it's in `trusted mode`.
+ */
+bool cpu_soc_is_in_untrusted_mode(void);
+
+/*
  * This function fills in the number of Cores(physical) and Threads(virtual)
  * of the CPU in the function arguments. It also returns if the number of cores
  * and number of threads are equal.