tree: Handle NULL pointer returned by smm_get_save_state()

Since commit 64d9e85681
("cpu/x86/smm_module_hander: Set up a save state map"), the
smm_get_save_state() function can return a NULL pointer. Therefore, it
is crucial to ensure that code properly handles the potential for a
NULL pointer return value from smm_get_save_state().

Change-Id: Ie263393ca7d9d6b5e9868c5f73240fc788116cd0
Signed-off-by: Jeremy Compostella <jeremy.compostella@intel.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/86040
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Elyes Haouas <ehaouas@noos.fr>

src/soc/amd/common/block/cpu/smm/smi_apmc.c

@@ -33,6 +33,8 @@ static void *find_save_state(int cmd)
 	/* Check all nodes looking for the one that issued the IO */
 	for (core = 0; core < CONFIG_MAX_CPUS; core++) {
 		state = smm_get_save_state(core);
+		if (!state)
+			continue;
 		smm_io_trap = state->smm_io_trap_offset;
 		/* Check for Valid IO Trap Word (bit1==1) */
 		if (!(smm_io_trap & SMM_IO_TRAP_VALID))

src/soc/intel/braswell/smihandler.c

@@ -176,6 +176,8 @@ static em64t100_smm_state_save_area_t *smi_apmc_find_state_save(uint8_t cmd)
 	/* Check all nodes looking for the one that issued the IO */
 	for (node = 0; node < CONFIG_MAX_CPUS; node++) {
 		state = smm_get_save_state(node);
+		if (!state)
+			continue;
 
 		/* Check for Synchronous IO (bit0==1) */
 		if (!(state->io_misc_info & (1 << 0)))

src/soc/intel/broadwell/pch/smihandler.c

@@ -228,6 +228,8 @@ static em64t101_smm_state_save_area_t *smi_apmc_find_state_save(u8 cmd)
 	/* Check all nodes looking for the one that issued the IO */
 	for (node = 0; node < CONFIG_MAX_CPUS; node++) {
 		state = smm_get_save_state(node);
+		if (!state)
+			continue;
 
 		/* Check for Synchronous IO (bit0 == 1) */
 		if (!(state->io_misc_info & (1 << 0)))

src/soc/intel/denverton_ns/smihandler.c

@@ -141,6 +141,8 @@ static em64t100_smm_state_save_area_t *smi_apmc_find_state_save(uint8_t cmd)
 	/* Check all nodes looking for the one that issued the IO */
 	for (node = 0; node < CONFIG_MAX_CPUS; node++) {
 		state = smm_get_save_state(node);
+		if (!state)
+			continue;
 
 		/* Check for Synchronous IO (bit0==1) */
 		if (!(state->io_misc_info & (1 << 0)))

src/southbridge/intel/common/smihandler.c

@@ -205,6 +205,8 @@ static em64t101_smm_state_save_area_t *smi_apmc_find_state_save(u8 cmd)
 	/* Check all nodes looking for the one that issued the IO */
 	for (node = 0; node < CONFIG_MAX_CPUS; node++) {
 		state = smm_get_save_state(node);
+		if (!state)
+			continue;
 
 		/* Check for Synchronous IO (bit0 == 1) */
 		if (!(state->io_misc_info & (1 << 0)))

src/southbridge/intel/lynxpoint/smihandler.c

@@ -177,6 +177,8 @@ static em64t101_smm_state_save_area_t *smi_apmc_find_state_save(u8 cmd)
 	/* Check all nodes looking for the one that issued the IO */
 	for (node = 0; node < CONFIG_MAX_CPUS; node++) {
 		state = smm_get_save_state(node);
+		if (!state)
+			continue;
 
 		/* Check for Synchronous IO (bit0 == 1) */
 		if (!(state->io_misc_info & (1 << 0)))