cpu/x86/smm: Enable setting SMM console log level from mainboard

Add a Kconfig RUNTIME_CONFIGURABLE_SMM_LOGLEVEL that enables
mainboard to override mainboard_set_smm_log_level for SMM log level.
This can let SMM have different log level than other stages for
more flexibility.

Another reason is that getting certain data that requires searching
from flash VPD or CMOS is not very ideal to be done in SMM, so in this
change the value can be passed via the member variable in struct
smm_runtime and be referenced directly in SMM.

One example is that mainboard can get the desired SMM log level from
VPD/CMOS, and pass SMM console log level via the variable and in SMM
it can be referenced in get_console_loglevel() override function
directly.

Tested=On OCP Delta Lake, verified SMM log level can be overridden.

Change-Id: I81722a4f1bf75ec942cc06e403ad702dfe938e71
Signed-off-by: Johnny Lin <johnny_lin@wiwynn.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/49460
Reviewed-by: David Hendricks <david.hendricks@gmail.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Jonathan Zhang <jonzhang@fb.com>

src/cpu/x86/Kconfig

@@ -209,4 +209,16 @@ config AP_STACK_SIZE
 	  This is the amount of stack each AP needs. The BSP stack size can be
 	  larger and is set with STACK_SIZE.
 
+config RUNTIME_CONFIGURABLE_SMM_LOGLEVEL
+	bool
+	default n
+	depends on DEBUG_SMI && CONSOLE_OVERRIDE_LOGLEVEL
+	help
+	  This enables setting the SMM console log level at runtime for more
+	  flexibility to use different log levels for each stage. Another reason
+	  is that reading the log level from non-volatile memory such as flash
+	  VPD or CMOS is not very ideal to be done in SMM, with this option the
+	  value can be passed via the member variable in struct smm_runtime and
+	  be referenced directly in SMM.
+
 endif # ARCH_X86

src/cpu/x86/smm/smm_module_handler.c

@@ -52,6 +52,13 @@ static void smi_release_lock(void)
 	);
 }
 
+#if CONFIG(RUNTIME_CONFIGURABLE_SMM_LOGLEVEL)
+int get_console_loglevel(void)
+{
+	return smm_runtime.smm_log_level;
+}
+#endif
+
 void smm_get_cbmemc_buffer(void **buffer_out, size_t *size_out)
 {
 	*buffer_out = smm_runtime.cbmemc;

src/cpu/x86/smm/smm_module_loader.c

@@ -338,6 +338,11 @@ static void setup_smihandler_params(struct smm_runtime *mod_params,
 
 	for (int i = 0; i < loader_params->num_cpus; i++)
 		mod_params->save_state_top[i] = region_end(&cpus[i].ss);
+
+	if (CONFIG(RUNTIME_CONFIGURABLE_SMM_LOGLEVEL))
+		mod_params->smm_log_level = mainboard_set_smm_log_level();
+	else
+		mod_params->smm_log_level = 0;
 }
 
 static void print_region(const char *name, const struct region region)

src/include/cpu/x86/smm.h

@@ -49,6 +49,7 @@ void mainboard_smi_gpi(u32 gpi_sts);
 int  mainboard_smi_apmc(u8 data);
 void mainboard_smi_sleep(u8 slp_typ);
 void mainboard_smi_finalize(void);
+int mainboard_set_smm_log_level(void);
 
 void smm_soc_early_init(void);
 void smm_soc_exit(void);
@@ -66,6 +67,7 @@ struct smm_runtime {
 	u32 cbmemc_size;
 	void *cbmemc;
 	uintptr_t save_state_top[CONFIG_MAX_CPUS];
+	int smm_log_level;
 } __packed;
 
 struct smm_module_params {