[M] Change in coreboot[master]: soc/intel/meteorlake: Allow to drop redundant CPU feature programming

[Lean Sheng Tan (Code Review)]

Lean Sheng Tan has submitted this change. ( https://review.coreboot.org/c/coreboot/+/74167 )

Change subject: soc/intel/meteorlake: Allow to drop redundant CPU feature programming
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soc/intel/meteorlake: Allow to drop redundant CPU feature programming

This patch introduces a new config named
`DROP_CPU_FEATURE_PROGRAM_IN_FSP` to avoid FSP running basic CPU
feature programming on BSP and on APs using the "CpuFeaturesPei.efi"
module.

Most of this feature programming is getting performed today in scope
of coreboot doing MP Init. Running this redundant programming in
scope of FSP (when `USE_FSP_FEATURE_PROGRAM_ON_APS` config is enabled)
results in CPU exception (for example: attempting to reprogram CPU
feature lock MSR is causing CPU exception).

SoC users should select this config after dropping "CpuFeaturesPei.ffs"
module from FSP-S Firmware Volume (FV). Upon selection, coreboot runs
those additional feature programming on BSP and APs.

This feature is by default enabled, in case of "coreboot running MP
init" aka `MP_SERVICES_PPI_V2_NOOP` config is selected.

At present, this option does not do anything unless any platform
eventually decides to drop FSP feature programming module and choose
coreboot CPU feature programming over it.

Signed-off-by: Subrata Banik 
Change-Id: I3be5329390401024d7ec9eed85a5afc35ab1b776
Reviewed-on: https://review.coreboot.org/c/coreboot/+/74167
Tested-by: build bot (Jenkins) 
Reviewed-by: Kapil Porwal 
Reviewed-by: Eric Lai 
Reviewed-by: Tarun Tuli 
---
M src/soc/intel/meteorlake/Kconfig
1 file changed, 58 insertions(+), 0 deletions(-)

Approvals:
  build bot (Jenkins): Verified
  Eric Lai: Looks good to me, approved
  Tarun Tuli: Looks good to me, approved
  Kapil Porwal: Looks good to me, approved

diff --git a/src/soc/intel/meteorlake/Kconfig b/src/soc/intel/meteorlake/Kconfig
index b29b3bc..3d99f81 100644
--- a/src/soc/intel/meteorlake/Kconfig
+++ b/src/soc/intel/meteorlake/Kconfig
@@ -364,4 +364,25 @@
    help
      Set this option if debug build of FSP is used.

+config DROP_CPU_FEATURE_PROGRAM_IN_FSP
+	bool
+	default y if MP_SERVICES_PPI_V2_NOOP
+	default n
+	help
+	  This is to avoid FSP running basic CPU feature programming on BSP
+	  and on APs using the "CpuFeaturesPei.efi" module. The feature programming
+	  includes enabling x2APIC, MCA, MCE and Turbo etc.
+
+	  Most of these feature programming are getting performed today in scope
+	  of coreboot doing MP Init. Running these redundant programming in scope
+	  of FSP (when `USE_FSP_FEATURE_PROGRAM_ON_APS` config is enabled) would
+	  results in CPU exception.
+
+	  SoC users to select this config after dropping "CpuFeaturesPei.ffs" module
+	  from FSP-S Firmware Volume (FV). Upon selection, coreboot runs those additional
+	  feature programming on BSP and APs.
+
+	  This feature is default enabled, in case of "coreboot running MP init"
+	  aka MP_SERVICES_PPI_V2_NOOP config is selected.
+
 endif