[coreboot-gerrit] [XS] Change in coreboot[main]: cpu/x86/smm: Fix smm_get_save_state() returning invalid pointer

[Elyes Haouas (Code Review)]

Elyes Haouas has submitted this change. ( https://review.coreboot.org/c/coreboot/+/86038?usp=email )

Change subject: cpu/x86/smm: Fix smm_get_save_state() returning invalid pointer
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cpu/x86/smm: Fix smm_get_save_state() returning invalid pointer

The smm_get_save_state() function returns an invalid pointer (negative
pointer) when the cpu variable is equal to the number of CPUs. This
leads to a hang when the pointer is used to access the save state.

TEST=No unexpected hangs in System Management Mode (SMM) were detected
     on fatcat.

Change-Id: I09f969105190a004372c43cb1542f5b716da1eda
Signed-off-by: Jeremy Compostella 
Reviewed-on: https://review.coreboot.org/c/coreboot/+/86038
Tested-by: build bot (Jenkins) 
Reviewed-by: Elyes Haouas 
Reviewed-by: Jamie Ryu 
---
M src/cpu/x86/smm/smm_module_handler.c
1 file changed, 1 insertion(+), 1 deletion(-)

Approvals:
  Elyes Haouas: Looks good to me, approved
  build bot (Jenkins): Verified
  Jamie Ryu: Looks good to me, approved

diff --git a/src/cpu/x86/smm/smm_module_handler.c b/src/cpu/x86/smm/smm_module_handler.c
index 899ee2f..d25b5f4 100644
--- a/src/cpu/x86/smm/smm_module_handler.c
+++ b/src/cpu/x86/smm/smm_module_handler.c
@@ -106,7 +106,7 @@

void *smm_get_save_state(int cpu)
 {
-	if (cpu > smm_runtime.num_cpus)
+	if (cpu >= smm_runtime.num_cpus)
    	return NULL;

return (void *)(smm_runtime.save_state_top[cpu] -