[armv8][mpu] Fix undefined behaviour in shifting 8 bit value (#1668)

ARM-software · Jul 31, 2024 · f979a19 · f979a19
1 parent 9aa50b3
commit f979a19
Showing 1 changed file with 2 additions and 1 deletion.
diff --git a/CMSIS/Core/Include/mpu_armv8.h b/CMSIS/Core/Include/mpu_armv8.h
@@ -261,12 +261,13 @@ __STATIC_INLINE void ARM_MPU_SetMemAttrEx(MPU_Type* mpu, uint8_t idx, uint8_t at
   const uint8_t reg = idx / 4U;
   const uint32_t pos = ((idx % 4U) * 8U);
   const uint32_t mask = 0xFFU << pos;
+  const uint32_t val = (uint32_t)attr << pos;
 
   if (reg >= (sizeof(mpu->MAIR) / sizeof(mpu->MAIR[0]))) {
     return; // invalid index
   }
 
-  mpu->MAIR[reg] = ((mpu->MAIR[reg] & ~mask) | ((attr << pos) & mask));
+  mpu->MAIR[reg] = ((mpu->MAIR[reg] & ~mask) | (val & mask));
 }
 
 /** Set the memory attribute encoding.