try with a loop

Author: Oren Cohen

core/vmpu/src/mpu_armv8m/vmpu_armv8m_unpriv_access.c

@@ -21,32 +21,41 @@
 #include "vmpu_mpu.h"
 #include "vmpu_unpriv_access.h"
 
+extern int vmpu_fault_recovery_mpu(uint32_t pc, uint32_t sp, uint32_t fault_addr, uint32_t fault_status);
+
 uint32_t vmpu_unpriv_access(uint32_t addr, uint32_t size, uint32_t data)
 {
-    // This operation could be slow since we are scanning all the regions defined for the box
-    // an implementation using the TTA command is faster but causes misses since it works with the MPU
-    if (vmpu_buffer_access_is_ok(g_active_box, (const void *) addr, UVISOR_UNPRIV_ACCESS_SIZE(size))){
-        switch(size) {
-            case UVISOR_UNPRIV_ACCESS_READ(1):
-                return *((uint8_t *) addr);
-            case UVISOR_UNPRIV_ACCESS_READ(2):
-                return *((uint16_t *) addr);
-            case UVISOR_UNPRIV_ACCESS_READ(4):
-                return *((uint32_t *) addr);
-            case UVISOR_UNPRIV_ACCESS_WRITE(1):
-                *((uint8_t *) addr) = (uint8_t) data;
-                return 0;
-            case UVISOR_UNPRIV_ACCESS_WRITE(2):
-                *((uint16_t *) addr) = (uint16_t) data;
-                return 0;
-            case UVISOR_UNPRIV_ACCESS_WRITE(4):
-                *((uint32_t *) addr) = data;
-                return 0;
-            default:
-                break;
+    unsigned int tries = 0;
+    while(1) {
+        // This operation could be slow since we are scanning all the regions defined for the box
+        // an implementation using the TTA command is faster but causes misses since it works with the MPU
+        if (vmpu_buffer_access_is_ok(g_active_box, (const void *) addr, UVISOR_UNPRIV_ACCESS_SIZE(size))){
+            switch(size) {
+                case UVISOR_UNPRIV_ACCESS_READ(1):
+                    return *((uint8_t *) addr);
+                case UVISOR_UNPRIV_ACCESS_READ(2):
+                    return *((uint16_t *) addr);
+                case UVISOR_UNPRIV_ACCESS_READ(4):
+                    return *((uint32_t *) addr);
+                case UVISOR_UNPRIV_ACCESS_WRITE(1):
+                    *((uint8_t *) addr) = (uint8_t) data;
+                    return 0;
+                case UVISOR_UNPRIV_ACCESS_WRITE(2):
+                    *((uint16_t *) addr) = (uint16_t) data;
+                    return 0;
+                case UVISOR_UNPRIV_ACCESS_WRITE(4):
+                    *((uint32_t *) addr) = data;
+                    return 0;
+                default:
+                    break;
+            }
+        }
+
+        if (++tries > 1 || !vmpu_fault_recovery_mpu(0, 0, addr, 0)) {
+            break;
         }
     }
-    
+
     HALT_ERROR(PERMISSION_DENIED, "Access to restricted resource denied");
     return 0;
 }