SMM: Avoid use of global variables in SMI handler

Using global variables with the TSEG is a bad idea because
they are not relocated properly right now.  Instead make
the variables static and add accessor functions for the
rest of SMM to use.

At the same time drop the tcg/smi1 pointers as they are
not setup or ever used.  (the debug output is added back
in a subsequent commit)

Change-Id: If0b2d47df4e482ead71bf713c1ef748da840073b
Signed-off-by: Duncan Laurie <dlaurie@chromium.org>
Reviewed-on: http://review.coreboot.org/1764
Tested-by: build bot (Jenkins)
Reviewed-by: Ronald G. Minnich <rminnich@gmail.com>

src/include/cpu/x86/smm.h

@@ -384,4 +384,7 @@ u32 smi_get_tseg_base(void);
 void tseg_relocate(void **ptr);
 #endif
 
+/* Get PMBASE address */
+u16 smm_get_pmbase(void);
+
 #endif

src/mainboard/intel/emeraldlake2/mainboard_smi.c

@@ -27,17 +27,12 @@
 #include <northbridge/intel/sandybridge/sandybridge.h>
 #include <cpu/intel/model_206ax/model_206ax.h>
 
-/* The southbridge SMI handler checks whether gnvs has a
- * valid pointer before calling the trap handler
- */
-extern global_nvs_t *gnvs;
-
 int mainboard_io_trap_handler(int smif)
 {
 	switch (smif) {
 	case 0x99:
 		printk(BIOS_DEBUG, "Sample\n");
-		gnvs->smif = 0;
+		smm_get_gnvs()->smif = 0;
 		break;
 	default:
 		return 0;

src/mainboard/samsung/lumpy/mainboard_smi.c

@@ -29,17 +29,12 @@
 #include <ec/smsc/mec1308/ec.h>
 #include "ec.h"
 
-/* The southbridge SMI handler checks whether gnvs has a
- * valid pointer before calling the trap handler
- */
-extern global_nvs_t *gnvs;
-
 int mainboard_io_trap_handler(int smif)
 {
 	switch (smif) {
 	case 0x99:
 		printk(BIOS_DEBUG, "Sample\n");
-		gnvs->smif = 0;
+		smm_get_gnvs()->smif = 0;
 		break;
 	default:
 		return 0;
@@ -59,7 +54,6 @@ static u8 mainboard_smi_ec(void)
 {
 	u8 cmd;
 	u32 pm1_cnt;
-	extern u16 pmbase; /* Set in southbridge SMI handler */
 
 	cmd = read_ec_command_byte(EC_GET_SMI_CAUSE);
 
@@ -68,9 +62,9 @@ static u8 mainboard_smi_ec(void)
 		printk(BIOS_DEBUG, "LID CLOSED, SHUTDOWN\n");
 
 		/* Go to S5 */
-		pm1_cnt = inl(pmbase + PM1_CNT);
+		pm1_cnt = inl(smm_get_pmbase() + PM1_CNT);
 		pm1_cnt |= (0xf << 10);
-		outl(pm1_cnt, pmbase + PM1_CNT);
+		outl(pm1_cnt, smm_get_pmbase() + PM1_CNT);
 		break;
 	}
 

src/mainboard/samsung/stumpy/mainboard_smi.c

@@ -30,17 +30,12 @@
 /* Include romstage serial for SIO helper functions */
 #include <superio/ite/it8772f/early_serial.c>
 
-/* The southbridge SMI handler checks whether gnvs has a
- * valid pointer before calling the trap handler
- */
-extern global_nvs_t *gnvs;
-
 int mainboard_io_trap_handler(int smif)
 {
 	switch (smif) {
 	case 0x99:
 		printk(BIOS_DEBUG, "Sample\n");
-		gnvs->smif = 0;
+		smm_get_gnvs()->smif = 0;
 		break;
 	default:
 		return 0;

src/southbridge/intel/bd82x6x/nvs.h

@@ -152,3 +152,7 @@ typedef struct {
 	chromeos_acpi_t chromeos;
 } __attribute__((packed)) global_nvs_t;
 
+#ifdef __SMM__
+/* Used in SMM to find the ACPI GNVS address */
+global_nvs_t *smm_get_gnvs(void);
+#endif

src/southbridge/intel/bd82x6x/smihandler.c

@@ -25,7 +25,6 @@
 #include <arch/romcc_io.h>
 #include <console/console.h>
 #include <cpu/x86/cache.h>
-#include <cpu/x86/smm.h>
 #include <device/pci_def.h>
 #include <cpu/x86/smm.h>
 #include <elog.h>
@@ -44,15 +43,22 @@
 /* While we read PMBASE dynamically in case it changed, let's
  * initialize it with a sane value
  */
-u16 pmbase = DEFAULT_PMBASE;
-u8 smm_initialized = 0;
+static u16 pmbase = DEFAULT_PMBASE;
+u16 smm_get_pmbase(void)
+{
+	return pmbase;
+}
+
+static u8 smm_initialized = 0;
 
 /* GNVS needs to be updated by an 0xEA PM Trap (B2) after it has been located
  * by coreboot.
  */
-global_nvs_t *gnvs = (global_nvs_t *)0x0;
-void *tcg = (void *)0x0;
-void *smi1 = (void *)0x0;
+static global_nvs_t *gnvs = (global_nvs_t *)0x0;
+global_nvs_t *smm_get_gnvs(void)
+{
+	return gnvs;
+}
 
 #if CONFIG_SMM_TSEG
 static u32 tseg_base = 0;
@@ -523,10 +529,7 @@ static void southbridge_smi_apmc(unsigned int node, smm_state_save_area_t *state
 			return;
 		}
 		gnvs = *(global_nvs_t **)0x500;
-		tcg  = *(void **)0x504;
-		smi1 = *(void **)0x508;
 		smm_initialized = 1;
-		printk(BIOS_DEBUG, "SMI#: Setting up structures to %p, %p, %p\n", gnvs, tcg, smi1);
 		break;
 #if CONFIG_ELOG_GSMI
 	case ELOG_GSMI_APM_CNT: