Add option to disable unprivileged critical sections

This commit introduces a new config configALLOW_UNPRIVILEGED_CRITICAL_SECTIONS which enables developers to prevent critical sections from unprivileged tasks. It defaults to 1 for backward compatibility. Application should set it to 0 to disable critical sections from unprivileged tasks. Signed-off-by: Gaurav Aggarwal <[email protected]>
FreeRTOS · Nov 15, 2021 · 44fc137 · 44fc137
1 parent 7a38487
commit 44fc137
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Showing 4 changed files with 92 additions and 8 deletions.
diff --git a/portable/GCC/ARM_CM3_MPU/port.c b/portable/GCC/ARM_CM3_MPU/port.c
@@ -52,6 +52,11 @@
     #define portNVIC_SYSTICK_CLK    ( 0 )
 #endif
 
+#ifndef configALLOW_UNPRIVILEGED_CRITICAL_SECTIONS
+    #warning "configALLOW_UNPRIVILEGED_CRITICAL_SECTIONS is not defined. We recommend defining it to 0 in FreeRTOSConfig.h for better security."
+    #define configALLOW_UNPRIVILEGED_CRITICAL_SECTIONS    1
+#endif
+
 /* Constants required to access and manipulate the NVIC. */
 #define portNVIC_SYSTICK_CTRL_REG                 ( *( ( volatile uint32_t * ) 0xe000e010 ) )
 #define portNVIC_SYSTICK_LOAD_REG                 ( *( ( volatile uint32_t * ) 0xe000e014 ) )
@@ -162,12 +167,20 @@ void vResetPrivilege( void ) __attribute__( ( naked ) );
 /**
  * @brief Enter critical section.
  */
-void vPortEnterCritical( void ) FREERTOS_SYSTEM_CALL;
+#if( configALLOW_UNPRIVILEGED_CRITICAL_SECTIONS == 1 )
+    void vPortEnterCritical( void ) FREERTOS_SYSTEM_CALL;
+#else
+    void vPortEnterCritical( void ) PRIVILEGED_FUNCTION;
+#endif
 
 /**
  * @brief Exit from critical section.
  */
-void vPortExitCritical( void ) FREERTOS_SYSTEM_CALL;
+#if( configALLOW_UNPRIVILEGED_CRITICAL_SECTIONS == 1 )
+    void vPortExitCritical( void ) FREERTOS_SYSTEM_CALL;
+#else
+    void vPortExitCritical( void ) PRIVILEGED_FUNCTION;
+#endif
 /*-----------------------------------------------------------*/
 
 /* Each task maintains its own interrupt status in the critical nesting
@@ -480,20 +493,26 @@ void vPortEndScheduler( void )
 
 void vPortEnterCritical( void )
 {
+#if( configALLOW_UNPRIVILEGED_CRITICAL_SECTIONS == 1 )
     BaseType_t xRunningPrivileged;
     xPortRaisePrivilege( xRunningPrivileged );
+#endif
 
     portDISABLE_INTERRUPTS();
     uxCriticalNesting++;
 
+#if( configALLOW_UNPRIVILEGED_CRITICAL_SECTIONS == 1 )
     vPortResetPrivilege( xRunningPrivileged );
+#endif
 }
 /*-----------------------------------------------------------*/
 
 void vPortExitCritical( void )
 {
+#if( configALLOW_UNPRIVILEGED_CRITICAL_SECTIONS == 1 )
     BaseType_t xRunningPrivileged;
     xPortRaisePrivilege( xRunningPrivileged );
+#endif
 
     configASSERT( uxCriticalNesting );
     uxCriticalNesting--;
@@ -503,7 +522,9 @@ void vPortExitCritical( void )
         portENABLE_INTERRUPTS();
     }
 
+#if( configALLOW_UNPRIVILEGED_CRITICAL_SECTIONS == 1 )
     vPortResetPrivilege( xRunningPrivileged );
+#endif
 }
 /*-----------------------------------------------------------*/
 

diff --git a/portable/GCC/ARM_CM4_MPU/port.c b/portable/GCC/ARM_CM4_MPU/port.c
@@ -56,6 +56,11 @@
     #define portNVIC_SYSTICK_CLK    ( 0 )
 #endif
 
+#ifndef configALLOW_UNPRIVILEGED_CRITICAL_SECTIONS
+    #warning "configALLOW_UNPRIVILEGED_CRITICAL_SECTIONS is not defined. We recommend defining it to 0 in FreeRTOSConfig.h for better security."
+    #define configALLOW_UNPRIVILEGED_CRITICAL_SECTIONS    1
+#endif
+
 /* Constants required to access and manipulate the NVIC. */
 #define portNVIC_SYSTICK_CTRL_REG                 ( *( ( volatile uint32_t * ) 0xe000e010 ) )
 #define portNVIC_SYSTICK_LOAD_REG                 ( *( ( volatile uint32_t * ) 0xe000e014 ) )
@@ -175,12 +180,20 @@ void vResetPrivilege( void ) __attribute__( ( naked ) );
 /**
  * @brief Enter critical section.
  */
-void vPortEnterCritical( void ) FREERTOS_SYSTEM_CALL;
+#if( configALLOW_UNPRIVILEGED_CRITICAL_SECTIONS == 1 )
+    void vPortEnterCritical( void ) FREERTOS_SYSTEM_CALL;
+#else
+    void vPortEnterCritical( void ) PRIVILEGED_FUNCTION;
+#endif
 
 /**
  * @brief Exit from critical section.
  */
-void vPortExitCritical( void ) FREERTOS_SYSTEM_CALL;
+#if( configALLOW_UNPRIVILEGED_CRITICAL_SECTIONS == 1 )
+    void vPortExitCritical( void ) FREERTOS_SYSTEM_CALL;
+#else
+    void vPortExitCritical( void ) PRIVILEGED_FUNCTION;
+#endif
 /*-----------------------------------------------------------*/
 
 /* Each task maintains its own interrupt status in the critical nesting
@@ -516,20 +529,26 @@ void vPortEndScheduler( void )
 
 void vPortEnterCritical( void )
 {
+#if( configALLOW_UNPRIVILEGED_CRITICAL_SECTIONS == 1 )
     BaseType_t xRunningPrivileged;
     xPortRaisePrivilege( xRunningPrivileged );
+#endif
 
     portDISABLE_INTERRUPTS();
     uxCriticalNesting++;
 
+#if( configALLOW_UNPRIVILEGED_CRITICAL_SECTIONS == 1 )
     vPortResetPrivilege( xRunningPrivileged );
+#endif
 }
 /*-----------------------------------------------------------*/
 
 void vPortExitCritical( void )
 {
+#if( configALLOW_UNPRIVILEGED_CRITICAL_SECTIONS == 1 )
     BaseType_t xRunningPrivileged;
     xPortRaisePrivilege( xRunningPrivileged );
+#endif
 
     configASSERT( uxCriticalNesting );
     uxCriticalNesting--;
@@ -539,7 +558,9 @@ void vPortExitCritical( void )
         portENABLE_INTERRUPTS();
     }
 
+#if( configALLOW_UNPRIVILEGED_CRITICAL_SECTIONS == 1 )
     vPortResetPrivilege( xRunningPrivileged );
+#endif
 }
 /*-----------------------------------------------------------*/
 

diff --git a/portable/IAR/ARM_CM4F_MPU/port.c b/portable/IAR/ARM_CM4F_MPU/port.c
@@ -63,6 +63,11 @@
     #define portNVIC_SYSTICK_CLK_BIT    ( 0 )
 #endif
 
+#ifndef configALLOW_UNPRIVILEGED_CRITICAL_SECTIONS
+    #warning "configALLOW_UNPRIVILEGED_CRITICAL_SECTIONS is not defined. We recommend defining it to 0 in FreeRTOSConfig.h for better security."
+    #define configALLOW_UNPRIVILEGED_CRITICAL_SECTIONS    1
+#endif
+
 /* Constants required to manipulate the core.  Registers first... */
 #define portNVIC_SYSTICK_CTRL_REG                 ( *( ( volatile uint32_t * ) 0xe000e010 ) )
 #define portNVIC_SYSTICK_LOAD_REG                 ( *( ( volatile uint32_t * ) 0xe000e014 ) )
@@ -188,12 +193,20 @@ extern void vPortRestoreContextOfFirstTask( void ) PRIVILEGED_FUNCTION;
 /**
  * @brief Enter critical section.
  */
-void vPortEnterCritical( void ) FREERTOS_SYSTEM_CALL;
+#if( configALLOW_UNPRIVILEGED_CRITICAL_SECTIONS == 1 )
+    void vPortEnterCritical( void ) FREERTOS_SYSTEM_CALL;
+#else
+    void vPortEnterCritical( void ) PRIVILEGED_FUNCTION;
+#endif
 
 /**
  * @brief Exit from critical section.
  */
-void vPortExitCritical( void ) FREERTOS_SYSTEM_CALL;
+#if( configALLOW_UNPRIVILEGED_CRITICAL_SECTIONS == 1 )
+    void vPortExitCritical( void ) FREERTOS_SYSTEM_CALL;
+#else
+    void vPortExitCritical( void ) PRIVILEGED_FUNCTION;
+#endif
 /*-----------------------------------------------------------*/
 
 /* Each task maintains its own interrupt status in the critical nesting
@@ -444,8 +457,10 @@ void vPortEndScheduler( void )
 
 void vPortEnterCritical( void )
 {
+#if( configALLOW_UNPRIVILEGED_CRITICAL_SECTIONS == 1 )
     BaseType_t xRunningPrivileged;
     xPortRaisePrivilege( xRunningPrivileged );
+#endif
 
     portDISABLE_INTERRUPTS();
     uxCriticalNesting++;
@@ -460,14 +475,18 @@ void vPortEnterCritical( void )
         configASSERT( ( portNVIC_INT_CTRL_REG & portVECTACTIVE_MASK ) == 0 );
     }
 
+#if( configALLOW_UNPRIVILEGED_CRITICAL_SECTIONS == 1 )
     vPortResetPrivilege( xRunningPrivileged );
+#endif
 }
 /*-----------------------------------------------------------*/
 
 void vPortExitCritical( void )
 {
+#if( configALLOW_UNPRIVILEGED_CRITICAL_SECTIONS == 1 )
     BaseType_t xRunningPrivileged;
     xPortRaisePrivilege( xRunningPrivileged );
+#endif
 
     configASSERT( uxCriticalNesting );
 
@@ -478,7 +497,9 @@ void vPortExitCritical( void )
         portENABLE_INTERRUPTS();
     }
 
+#if( configALLOW_UNPRIVILEGED_CRITICAL_SECTIONS == 1 )
     vPortResetPrivilege( xRunningPrivileged );
+#endif
 }
 /*-----------------------------------------------------------*/
 

diff --git a/portable/RVDS/ARM_CM4_MPU/port.c b/portable/RVDS/ARM_CM4_MPU/port.c
@@ -45,6 +45,11 @@
 
 #undef MPU_WRAPPERS_INCLUDED_FROM_API_FILE
 
+#ifndef configALLOW_UNPRIVILEGED_CRITICAL_SECTIONS
+    #warning "configALLOW_UNPRIVILEGED_CRITICAL_SECTIONS is not defined. We recommend defining it to 0 in FreeRTOSConfig.h for better security."
+    #define configALLOW_UNPRIVILEGED_CRITICAL_SECTIONS    1
+#endif
+
 /* Constants required to access and manipulate the NVIC. */
 #define portNVIC_SYSTICK_CTRL_REG                 ( *( ( volatile uint32_t * ) 0xe000e010 ) )
 #define portNVIC_SYSTICK_LOAD_REG                 ( *( ( volatile uint32_t * ) 0xe000e014 ) )
@@ -189,12 +194,20 @@ void vResetPrivilege( void );
 /**
  * @brief Enter critical section.
  */
-void vPortEnterCritical( void ) FREERTOS_SYSTEM_CALL;
+#if( configALLOW_UNPRIVILEGED_CRITICAL_SECTIONS == 1 )
+    void vPortEnterCritical( void ) FREERTOS_SYSTEM_CALL;
+#else
+    void vPortEnterCritical( void ) PRIVILEGED_FUNCTION;
+#endif
 
 /**
  * @brief Exit from critical section.
  */
-void vPortExitCritical( void ) FREERTOS_SYSTEM_CALL;
+#if( configALLOW_UNPRIVILEGED_CRITICAL_SECTIONS == 1 )
+    void vPortExitCritical( void ) FREERTOS_SYSTEM_CALL;
+#else
+    void vPortExitCritical( void ) PRIVILEGED_FUNCTION;
+#endif
 /*-----------------------------------------------------------*/
 
 /*
@@ -519,20 +532,26 @@ void vPortEndScheduler( void )
 
 void vPortEnterCritical( void )
 {
+#if( configALLOW_UNPRIVILEGED_CRITICAL_SECTIONS == 1 )
     BaseType_t xRunningPrivileged;
     xPortRaisePrivilege( xRunningPrivileged );
+#endif
 
     portDISABLE_INTERRUPTS();
     uxCriticalNesting++;
 
+#if( configALLOW_UNPRIVILEGED_CRITICAL_SECTIONS == 1 )
     vPortResetPrivilege( xRunningPrivileged );
+#endif
 }
 /*-----------------------------------------------------------*/
 
 void vPortExitCritical( void )
 {
+#if( configALLOW_UNPRIVILEGED_CRITICAL_SECTIONS == 1 )
     BaseType_t xRunningPrivileged;
     xPortRaisePrivilege( xRunningPrivileged );
+#endif
 
     configASSERT( uxCriticalNesting );
     uxCriticalNesting--;
@@ -542,7 +561,9 @@ void vPortExitCritical( void )
         portENABLE_INTERRUPTS();
     }
 
+#if( configALLOW_UNPRIVILEGED_CRITICAL_SECTIONS == 1 )
     vPortResetPrivilege( xRunningPrivileged );
+#endif
 }
 /*-----------------------------------------------------------*/