fix(versal-net): add redundant call to avoid glitches
Add redundant macro call to increase security by making
code glitch immune as security operations might be
called with the IPI command.
Signed-off-by: Jay Buddhabhatti <jay.buddhabhatti@amd.com>
Change-Id: I84d84cca258b7cd981f62816c51032341e19095c
diff --git a/plat/xilinx/common/include/pm_svc_main.h b/plat/xilinx/common/include/pm_svc_main.h
index 1a27bdf..4cf7727 100644
--- a/plat/xilinx/common/include/pm_svc_main.h
+++ b/plat/xilinx/common/include/pm_svc_main.h
@@ -10,6 +10,26 @@
#include <pm_common.h>
+/******************************************************************************/
+/**
+ * SECURE_REDUNDANT_CALL() - Adds redundancy to the function call. This is to
+ * avoid glitches which can skip a function call
+ * and cause altering of the code flow in security
+ * critical functions.
+ * @status: Variable which holds the return value of function executed
+ * @status_tmp: Variable which holds the return value of redundant function
+ * call executed
+ * @function: Function to be executed
+ *
+ * Return: None
+ *
+ ******************************************************************************/
+#define SECURE_REDUNDANT_CALL(status, status_tmp, function, ...) \
+ { \
+ status = function(__VA_ARGS__); \
+ status_tmp = function(__VA_ARGS__); \
+ }
+
int32_t pm_setup(void);
uint64_t pm_smc_handler(uint32_t smc_fid, uint64_t x1, uint64_t x2, uint64_t x3,
uint64_t x4, const void *cookie, void *handle,
diff --git a/plat/xilinx/common/pm_service/pm_svc_main.c b/plat/xilinx/common/pm_service/pm_svc_main.c
index 0e54f9a..1e5808c 100644
--- a/plat/xilinx/common/pm_service/pm_svc_main.c
+++ b/plat/xilinx/common/pm_service/pm_svc_main.c
@@ -23,6 +23,7 @@
#include "pm_api_sys.h"
#include "pm_client.h"
#include "pm_ipi.h"
+#include "pm_svc_main.h"
#define MODE 0x80000000U
@@ -401,6 +402,7 @@
uint32_t pm_arg[PAYLOAD_ARG_CNT] = {0};
uint32_t security_flag = NON_SECURE_FLAG;
uint32_t api_id;
+ bool status = false, status_tmp = false;
/* Handle case where PM wasn't initialized properly */
if (pm_up == false) {
@@ -410,8 +412,11 @@
/*
* Mark BIT24 payload (i.e 1st bit of pm_arg[3] ) as secure (0)
* if smc called is secure
+ *
+ * Add redundant macro call to immune the code from glitches
*/
- if (is_caller_secure(flags)) {
+ SECURE_REDUNDANT_CALL(status, status_tmp, is_caller_secure, flags);
+ if ((status != false) && (status_tmp != false)) {
security_flag = SECURE_FLAG;
}