5 files changed, 52 insertions, 10 deletions
diff --git a/src/soc/amd/common/block/cpu/Kconfig b/src/soc/amd/common/block/cpu/Kconfig
index f926887cf5..1ffaece9dd 100644
--- a/src/soc/amd/common/block/cpu/Kconfig
+++ b/src/soc/amd/common/block/cpu/Kconfig
@@ -85,6 +85,15 @@ config SOC_AMD_COMMON_BLOCK_SMM
 	  Add common SMM relocation, finalization and handler functionality to
 	  the build.
 
+config SOC_AMD_COMMON_LATE_SMM_LOCKING
+	bool
+	depends on SOC_AMD_COMMON_BLOCK_SMM
+	help
+	  Select this option to perform SMM locking late in soc_finalize(), rather than earlier
+	  in smm_relocation_handler(). This is required for pre-Zen SoCs like Stoneyridge which
+	  call into an AGESA binary as part of S3 resume, and require SMM to still be unlocked
+	  at that time.
+
 config SOC_AMD_COMMON_BLOCK_SVI2
 	bool
 	help
diff --git a/src/soc/amd/common/block/cpu/smm/finalize.c b/src/soc/amd/common/block/cpu/smm/finalize.c
index b81b9bcd1d..a3ba188d9e 100644
--- a/src/soc/amd/common/block/cpu/smm/finalize.c
+++ b/src/soc/amd/common/block/cpu/smm/finalize.c
@@ -9,8 +9,30 @@
 #include <cpu/x86/msr.h>
 #include <types.h>
 
+static void late_smm_lock(void *unused)
+{
+	/* Finalize SMM settings */
+	if (is_smm_locked()) /* Skip if already locked, avoid GPF */
+		return;
+
+	if (CONFIG(HAVE_SMI_HANDLER))
+		tseg_valid();
+
+	lock_smm();
+}
+
+static void late_smm_finalize(void)
+{
+	printk(BIOS_SPEW, "Lock SMM configuration\n");
+	if (mp_run_on_all_cpus(late_smm_lock, NULL) != CB_SUCCESS)
+		printk(BIOS_WARNING, "Failed to finalize all cores\n");
+}
+
 static void soc_finalize(void *unused)
 {
+	if (CONFIG(SOC_AMD_COMMON_LATE_SMM_LOCKING))
+		late_smm_finalize();
+
 	if (!acpi_is_wakeup_s3()) {
 		acpi_clear_pm_gpe_status();
 
diff --git a/src/soc/amd/common/block/cpu/smm/smm_helper.c b/src/soc/amd/common/block/cpu/smm/smm_helper.c
index a6e7d2dac5..e87d12c641 100644
--- a/src/soc/amd/common/block/cpu/smm/smm_helper.c
+++ b/src/soc/amd/common/block/cpu/smm/smm_helper.c
@@ -30,6 +30,20 @@ void clear_tvalid(void)
 	wrmsr(SMM_MASK_MSR, mask);
 }
 
+void tseg_valid(void)
+{
+	msr_t mask = rdmsr(SMM_MASK_MSR);
+	mask.lo |= SMM_TSEG_VALID;
+
+	wrmsr(SMM_MASK_MSR, mask);
+}
+
+bool is_smm_locked(void)
+{
+	msr_t hwcr = rdmsr(HWCR_MSR);
+	return hwcr.lo & SMM_LOCK ? true : false;
+}
+
 void lock_smm(void)
 {
 	msr_t hwcr = rdmsr(HWCR_MSR);
diff --git a/src/soc/amd/common/block/cpu/smm/smm_relocate.c b/src/soc/amd/common/block/cpu/smm/smm_relocate.c
index ae008853bd..d01f4c3e2d 100644
--- a/src/soc/amd/common/block/cpu/smm/smm_relocate.c
+++ b/src/soc/amd/common/block/cpu/smm/smm_relocate.c
@@ -52,14 +52,6 @@ static void get_smm_info(uintptr_t *perm_smbase, size_t *perm_smsize,
 	*smm_save_state_size = sizeof(amd64_smm_state_save_area_t);
 }
 
-static void tseg_valid(void)
-{
-	msr_t mask = rdmsr(SMM_MASK_MSR);
-	mask.lo |= SMM_TSEG_VALID;
-
-	wrmsr(SMM_MASK_MSR, mask);
-}
-
 static void smm_relocation_handler(void)
 {
 	uintptr_t tseg_base;
@@ -87,8 +79,11 @@ static void smm_relocation_handler(void)
 	};
 	wrmsr(SMM_BASE_MSR, smm_base);
 
-	tseg_valid();
-	lock_smm();
+
+	if (!CONFIG(SOC_AMD_COMMON_LATE_SMM_LOCKING)) {
+		tseg_valid();
+		lock_smm();
+	}
 }
 
 static void post_mp_init(void)
diff --git a/src/soc/amd/common/block/include/amdblocks/smm.h b/src/soc/amd/common/block/include/amdblocks/smm.h
index 97b11be609..bcd30f8ed2 100644
--- a/src/soc/amd/common/block/include/amdblocks/smm.h
+++ b/src/soc/amd/common/block/include/amdblocks/smm.h
@@ -11,6 +11,8 @@ void handle_smi_gsmi(void);
 void handle_smi_store(void);
 void fch_apmc_smi_handler(void);
 void clear_tvalid(void);
+void tseg_valid(void);
+bool is_smm_locked(void);
 void lock_smm(void);
 /* See SMITYPE_* for list possible of events. GEVENTS are handled with mainboard_smi_gpi. */
 void mainboard_handle_smi(int event);