Disable stack overflow check for MPU ports (FreeRTOS#1231)

Disable stack overflow check for MPU ports Stack overflow check is not straight forward to implement for MPU ports because of the following reasons: 1. The context is stroed in TCB and as a result, pxTopOfStack member points to the context location in TCB. 2. System calls are executed on a separate privileged only stack. It is still okay because an MPU region is used to protect task stack which means task stack overflow will trigger an MPU fault. Signed-off-by: Gaurav Aggarwal <[email protected]>
sudeep-mohanty · Feb 24, 2025 · df0aa5a · df0aa5a
1 parent 1a1ae36
commit df0aa5a
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Showing 23 changed files with 42 additions and 150 deletions.
diff --git a/include/portable.h b/include/portable.h
@@ -93,10 +93,6 @@
     #define portBASE_TYPE_EXIT_CRITICAL()    taskEXIT_CRITICAL()
 #endif
 
-#ifndef portGET_CURRENT_TOP_OF_STACK
-    #define portGET_CURRENT_TOP_OF_STACK( pxCurrentTopOfStack )    { pxCurrentTopOfStack = ( StackType_t * ) pxCurrentTCB->pxTopOfStack; }
-#endif
-
 #ifndef configSTACK_DEPTH_TYPE
     #define configSTACK_DEPTH_TYPE    StackType_t
 #endif

diff --git a/include/stack_macros.h b/include/stack_macros.h
@@ -53,17 +53,25 @@
     #define portSTACK_LIMIT_PADDING    0
 #endif
 
-#if ( ( configCHECK_FOR_STACK_OVERFLOW == 1 ) && ( portSTACK_GROWTH < 0 ) )
+/* Stack overflow check is not straight forward to implement for MPU ports
+ * because of the following reasons:
+ * 1. The context is stored in TCB and as a result, pxTopOfStack member points
+ *    to the context location in TCB.
+ * 2. System calls are executed on a separate privileged only stack.
+ *
+ * It is still okay because an MPU region is used to protect task stack which
+ * means task stack overflow will trigger an MPU fault for unprivileged tasks.
+ * Additionally, architectures with hardware stack overflow checking support
+ * (such as Armv8-M) will trigger a fault when a task's stack overflows.
+ */
+#if ( ( configCHECK_FOR_STACK_OVERFLOW == 1 ) && ( portSTACK_GROWTH < 0 ) && ( portUSING_MPU_WRAPPERS != 1 ) )
 
 /* Only the current stack state is to be checked. */
     #define taskCHECK_FOR_STACK_OVERFLOW()                                                      \
     do                                                                                          \
     {                                                                                           \
-        StackType_t * pxCurrentTopOfStack;                                                      \
-        portGET_CURRENT_TOP_OF_STACK( pxCurrentTopOfStack );                                    \
-                                                                                                \
         /* Is the currently saved stack pointer within the stack limit? */                      \
-        if( pxCurrentTopOfStack <= pxCurrentTCB->pxStack + portSTACK_LIMIT_PADDING )            \
+        if( pxCurrentTCB->pxTopOfStack <= pxCurrentTCB->pxStack + portSTACK_LIMIT_PADDING )     \
         {                                                                                       \
             char * pcOverflowTaskName = pxCurrentTCB->pcTaskName;                               \
             vApplicationStackOverflowHook( ( TaskHandle_t ) pxCurrentTCB, pcOverflowTaskName ); \
@@ -73,51 +81,46 @@
 #endif /* configCHECK_FOR_STACK_OVERFLOW == 1 */
 /*-----------------------------------------------------------*/
 
-#if ( ( configCHECK_FOR_STACK_OVERFLOW == 1 ) && ( portSTACK_GROWTH > 0 ) )
+#if ( ( configCHECK_FOR_STACK_OVERFLOW == 1 ) && ( portSTACK_GROWTH > 0 ) && ( portUSING_MPU_WRAPPERS != 1 ) )
 
 /* Only the current stack state is to be checked. */
-    #define taskCHECK_FOR_STACK_OVERFLOW()                                                      \
-    do                                                                                          \
-    {                                                                                           \
-        StackType_t * pxCurrentTopOfStack;                                                      \
-        portGET_CURRENT_TOP_OF_STACK( pxCurrentTopOfStack );                                    \
-                                                                                                \
-        /* Is the currently saved stack pointer within the stack limit? */                      \
-        if( pxCurrentTopOfStack >= pxCurrentTCB->pxEndOfStack - portSTACK_LIMIT_PADDING )       \
-        {                                                                                       \
-            char * pcOverflowTaskName = pxCurrentTCB->pcTaskName;                               \
-            vApplicationStackOverflowHook( ( TaskHandle_t ) pxCurrentTCB, pcOverflowTaskName ); \
-        }                                                                                       \
+    #define taskCHECK_FOR_STACK_OVERFLOW()                                                       \
+    do                                                                                           \
+    {                                                                                            \
+        /* Is the currently saved stack pointer within the stack limit? */                       \
+        if( pxCurrentTCB->pxTopOfStack >= pxCurrentTCB->pxEndOfStack - portSTACK_LIMIT_PADDING ) \
+        {                                                                                        \
+            char * pcOverflowTaskName = pxCurrentTCB->pcTaskName;                                \
+            vApplicationStackOverflowHook( ( TaskHandle_t ) pxCurrentTCB, pcOverflowTaskName );  \
+        }                                                                                        \
     } while( 0 )
 
 #endif /* configCHECK_FOR_STACK_OVERFLOW == 1 */
 /*-----------------------------------------------------------*/
 
-#if ( ( configCHECK_FOR_STACK_OVERFLOW > 1 ) && ( portSTACK_GROWTH < 0 ) )
-
-    #define taskCHECK_FOR_STACK_OVERFLOW()                                                      \
-    do                                                                                          \
-    {                                                                                           \
-        const uint32_t * const pulStack = ( uint32_t * ) pxCurrentTCB->pxStack;                 \
-        const uint32_t ulCheckValue = ( uint32_t ) 0xa5a5a5a5U;                                 \
-        StackType_t * pxCurrentTopOfStack;                                                      \
-        portGET_CURRENT_TOP_OF_STACK( pxCurrentTopOfStack );                                    \
-                                                                                                \
-        if( ( pxCurrentTopOfStack <= pxCurrentTCB->pxStack + portSTACK_LIMIT_PADDING ) ||       \
-            ( pulStack[ 0 ] != ulCheckValue ) ||                                                \
-            ( pulStack[ 1 ] != ulCheckValue ) ||                                                \
-            ( pulStack[ 2 ] != ulCheckValue ) ||                                                \
-            ( pulStack[ 3 ] != ulCheckValue ) )                                                 \
-        {                                                                                       \
-            char * pcOverflowTaskName = pxCurrentTCB->pcTaskName;                               \
-            vApplicationStackOverflowHook( ( TaskHandle_t ) pxCurrentTCB, pcOverflowTaskName ); \
-        }                                                                                       \
+#if ( ( configCHECK_FOR_STACK_OVERFLOW > 1 ) && ( portSTACK_GROWTH < 0 ) && ( portUSING_MPU_WRAPPERS != 1 ) )
+
+    #define taskCHECK_FOR_STACK_OVERFLOW()                                                       \
+    do                                                                                           \
+    {                                                                                            \
+        const uint32_t * const pulStack = ( uint32_t * ) pxCurrentTCB->pxStack;                  \
+        const uint32_t ulCheckValue = ( uint32_t ) 0xa5a5a5a5U;                                  \
+                                                                                                 \
+        if( ( pxCurrentTCB->pxTopOfStack <= pxCurrentTCB->pxStack + portSTACK_LIMIT_PADDING ) || \
+            ( pulStack[ 0 ] != ulCheckValue ) ||                                                 \
+            ( pulStack[ 1 ] != ulCheckValue ) ||                                                 \
+            ( pulStack[ 2 ] != ulCheckValue ) ||                                                 \
+            ( pulStack[ 3 ] != ulCheckValue ) )                                                  \
+        {                                                                                        \
+            char * pcOverflowTaskName = pxCurrentTCB->pcTaskName;                                \
+            vApplicationStackOverflowHook( ( TaskHandle_t ) pxCurrentTCB, pcOverflowTaskName );  \
+        }                                                                                        \
     } while( 0 )
 
 #endif /* #if( configCHECK_FOR_STACK_OVERFLOW > 1 ) */
 /*-----------------------------------------------------------*/
 
-#if ( ( configCHECK_FOR_STACK_OVERFLOW > 1 ) && ( portSTACK_GROWTH > 0 ) )
+#if ( ( configCHECK_FOR_STACK_OVERFLOW > 1 ) && ( portSTACK_GROWTH > 0 ) && ( portUSING_MPU_WRAPPERS != 1 ) )
 
     #define taskCHECK_FOR_STACK_OVERFLOW()                                                                                                \
     do                                                                                                                                    \
@@ -128,12 +131,10 @@
                                                         tskSTACK_FILL_BYTE, tskSTACK_FILL_BYTE, tskSTACK_FILL_BYTE, tskSTACK_FILL_BYTE,   \
                                                         tskSTACK_FILL_BYTE, tskSTACK_FILL_BYTE, tskSTACK_FILL_BYTE, tskSTACK_FILL_BYTE,   \
                                                         tskSTACK_FILL_BYTE, tskSTACK_FILL_BYTE, tskSTACK_FILL_BYTE, tskSTACK_FILL_BYTE }; \
-        StackType_t * pxCurrentTopOfStack;                                                                                                \
-        portGET_CURRENT_TOP_OF_STACK( pxCurrentTopOfStack );                                                                              \
                                                                                                                                           \
         pcEndOfStack -= sizeof( ucExpectedStackBytes );                                                                                   \
                                                                                                                                           \
-        if( ( pxCurrentTopOfStack >= pxCurrentTCB->pxEndOfStack - portSTACK_LIMIT_PADDING ) ||                                            \
+        if( ( pxCurrentTCB->pxTopOfStack >= pxCurrentTCB->pxEndOfStack - portSTACK_LIMIT_PADDING ) ||                                     \
             ( memcmp( ( void * ) pcEndOfStack, ( void * ) ucExpectedStackBytes, sizeof( ucExpectedStackBytes ) ) != 0 ) )                 \
         {                                                                                                                                 \
             char * pcOverflowTaskName = pxCurrentTCB->pcTaskName;                                                                         \

diff --git a/portable/ARMv8M/non_secure/portmacrocommon.h b/portable/ARMv8M/non_secure/portmacrocommon.h
@@ -217,11 +217,6 @@ extern void vClearInterruptMask( uint32_t ulMask ) /* __attribute__(( naked )) P
             #error configSYSTEM_CALL_STACK_SIZE must be defined to the desired size of the system call stack in words for using MPU wrappers v2.
         #endif
 
-        /* When MPU wrapper v2 is used, the task's context is stored in TCB and
-         * pxTopOfStack member of TCB points to the context location in TCB. We,
-         * therefore, need to read PSP to find the task's current top of stack. */
-        #define portGET_CURRENT_TOP_OF_STACK( pxCurrentTopOfStack ) { __asm volatile ( "mrs %0, psp"  : "=r" ( pxCurrentTopOfStack ) ); }
-
         /**
          * @brief System call stack.
          */

diff --git a/portable/GCC/ARM_CM23/non_secure/portmacrocommon.h b/portable/GCC/ARM_CM23/non_secure/portmacrocommon.h
@@ -217,11 +217,6 @@ extern void vClearInterruptMask( uint32_t ulMask ) /* __attribute__(( naked )) P
             #error configSYSTEM_CALL_STACK_SIZE must be defined to the desired size of the system call stack in words for using MPU wrappers v2.
         #endif
 
-        /* When MPU wrapper v2 is used, the task's context is stored in TCB and
-         * pxTopOfStack member of TCB points to the context location in TCB. We,
-         * therefore, need to read PSP to find the task's current top of stack. */
-        #define portGET_CURRENT_TOP_OF_STACK( pxCurrentTopOfStack ) { __asm volatile ( "mrs %0, psp"  : "=r" ( pxCurrentTopOfStack ) ); }
-
         /**
          * @brief System call stack.
          */

diff --git a/portable/GCC/ARM_CM23_NTZ/non_secure/portmacrocommon.h b/portable/GCC/ARM_CM23_NTZ/non_secure/portmacrocommon.h
@@ -217,11 +217,6 @@ extern void vClearInterruptMask( uint32_t ulMask ) /* __attribute__(( naked )) P
             #error configSYSTEM_CALL_STACK_SIZE must be defined to the desired size of the system call stack in words for using MPU wrappers v2.
         #endif
 
-        /* When MPU wrapper v2 is used, the task's context is stored in TCB and
-         * pxTopOfStack member of TCB points to the context location in TCB. We,
-         * therefore, need to read PSP to find the task's current top of stack. */
-        #define portGET_CURRENT_TOP_OF_STACK( pxCurrentTopOfStack ) { __asm volatile ( "mrs %0, psp"  : "=r" ( pxCurrentTopOfStack ) ); }
-
         /**
          * @brief System call stack.
          */

diff --git a/portable/GCC/ARM_CM33/non_secure/portmacrocommon.h b/portable/GCC/ARM_CM33/non_secure/portmacrocommon.h
@@ -217,11 +217,6 @@ extern void vClearInterruptMask( uint32_t ulMask ) /* __attribute__(( naked )) P
             #error configSYSTEM_CALL_STACK_SIZE must be defined to the desired size of the system call stack in words for using MPU wrappers v2.
         #endif
 
-        /* When MPU wrapper v2 is used, the task's context is stored in TCB and
-         * pxTopOfStack member of TCB points to the context location in TCB. We,
-         * therefore, need to read PSP to find the task's current top of stack. */
-        #define portGET_CURRENT_TOP_OF_STACK( pxCurrentTopOfStack ) { __asm volatile ( "mrs %0, psp"  : "=r" ( pxCurrentTopOfStack ) ); }
-
         /**
          * @brief System call stack.
          */

diff --git a/portable/GCC/ARM_CM33_NTZ/non_secure/portmacrocommon.h b/portable/GCC/ARM_CM33_NTZ/non_secure/portmacrocommon.h
@@ -217,11 +217,6 @@ extern void vClearInterruptMask( uint32_t ulMask ) /* __attribute__(( naked )) P
             #error configSYSTEM_CALL_STACK_SIZE must be defined to the desired size of the system call stack in words for using MPU wrappers v2.
         #endif
 
-        /* When MPU wrapper v2 is used, the task's context is stored in TCB and
-         * pxTopOfStack member of TCB points to the context location in TCB. We,
-         * therefore, need to read PSP to find the task's current top of stack. */
-        #define portGET_CURRENT_TOP_OF_STACK( pxCurrentTopOfStack ) { __asm volatile ( "mrs %0, psp"  : "=r" ( pxCurrentTopOfStack ) ); }
-
         /**
          * @brief System call stack.
          */

diff --git a/portable/GCC/ARM_CM35P/non_secure/portmacrocommon.h b/portable/GCC/ARM_CM35P/non_secure/portmacrocommon.h
@@ -217,11 +217,6 @@ extern void vClearInterruptMask( uint32_t ulMask ) /* __attribute__(( naked )) P
             #error configSYSTEM_CALL_STACK_SIZE must be defined to the desired size of the system call stack in words for using MPU wrappers v2.
         #endif
 
-        /* When MPU wrapper v2 is used, the task's context is stored in TCB and
-         * pxTopOfStack member of TCB points to the context location in TCB. We,
-         * therefore, need to read PSP to find the task's current top of stack. */
-        #define portGET_CURRENT_TOP_OF_STACK( pxCurrentTopOfStack ) { __asm volatile ( "mrs %0, psp"  : "=r" ( pxCurrentTopOfStack ) ); }
-
         /**
          * @brief System call stack.
          */

diff --git a/portable/GCC/ARM_CM35P_NTZ/non_secure/portmacrocommon.h b/portable/GCC/ARM_CM35P_NTZ/non_secure/portmacrocommon.h
@@ -217,11 +217,6 @@ extern void vClearInterruptMask( uint32_t ulMask ) /* __attribute__(( naked )) P
             #error configSYSTEM_CALL_STACK_SIZE must be defined to the desired size of the system call stack in words for using MPU wrappers v2.
         #endif
 
-        /* When MPU wrapper v2 is used, the task's context is stored in TCB and
-         * pxTopOfStack member of TCB points to the context location in TCB. We,
-         * therefore, need to read PSP to find the task's current top of stack. */
-        #define portGET_CURRENT_TOP_OF_STACK( pxCurrentTopOfStack ) { __asm volatile ( "mrs %0, psp"  : "=r" ( pxCurrentTopOfStack ) ); }
-
         /**
          * @brief System call stack.
          */

diff --git a/portable/GCC/ARM_CM55/non_secure/portmacrocommon.h b/portable/GCC/ARM_CM55/non_secure/portmacrocommon.h
@@ -217,11 +217,6 @@ extern void vClearInterruptMask( uint32_t ulMask ) /* __attribute__(( naked )) P
             #error configSYSTEM_CALL_STACK_SIZE must be defined to the desired size of the system call stack in words for using MPU wrappers v2.
         #endif
 
-        /* When MPU wrapper v2 is used, the task's context is stored in TCB and
-         * pxTopOfStack member of TCB points to the context location in TCB. We,
-         * therefore, need to read PSP to find the task's current top of stack. */
-        #define portGET_CURRENT_TOP_OF_STACK( pxCurrentTopOfStack ) { __asm volatile ( "mrs %0, psp"  : "=r" ( pxCurrentTopOfStack ) ); }
-
         /**
          * @brief System call stack.
          */

diff --git a/portable/GCC/ARM_CM55_NTZ/non_secure/portmacrocommon.h b/portable/GCC/ARM_CM55_NTZ/non_secure/portmacrocommon.h
@@ -217,11 +217,6 @@ extern void vClearInterruptMask( uint32_t ulMask ) /* __attribute__(( naked )) P
             #error configSYSTEM_CALL_STACK_SIZE must be defined to the desired size of the system call stack in words for using MPU wrappers v2.
         #endif
 
-        /* When MPU wrapper v2 is used, the task's context is stored in TCB and
-         * pxTopOfStack member of TCB points to the context location in TCB. We,
-         * therefore, need to read PSP to find the task's current top of stack. */
-        #define portGET_CURRENT_TOP_OF_STACK( pxCurrentTopOfStack ) { __asm volatile ( "mrs %0, psp"  : "=r" ( pxCurrentTopOfStack ) ); }
-
         /**
          * @brief System call stack.
          */

diff --git a/portable/GCC/ARM_CM85/non_secure/portmacrocommon.h b/portable/GCC/ARM_CM85/non_secure/portmacrocommon.h
@@ -217,11 +217,6 @@ extern void vClearInterruptMask( uint32_t ulMask ) /* __attribute__(( naked )) P
             #error configSYSTEM_CALL_STACK_SIZE must be defined to the desired size of the system call stack in words for using MPU wrappers v2.
         #endif
 
-        /* When MPU wrapper v2 is used, the task's context is stored in TCB and
-         * pxTopOfStack member of TCB points to the context location in TCB. We,
-         * therefore, need to read PSP to find the task's current top of stack. */
-        #define portGET_CURRENT_TOP_OF_STACK( pxCurrentTopOfStack ) { __asm volatile ( "mrs %0, psp"  : "=r" ( pxCurrentTopOfStack ) ); }
-
         /**
          * @brief System call stack.
          */

diff --git a/portable/GCC/ARM_CM85_NTZ/non_secure/portmacrocommon.h b/portable/GCC/ARM_CM85_NTZ/non_secure/portmacrocommon.h
@@ -217,11 +217,6 @@ extern void vClearInterruptMask( uint32_t ulMask ) /* __attribute__(( naked )) P
             #error configSYSTEM_CALL_STACK_SIZE must be defined to the desired size of the system call stack in words for using MPU wrappers v2.
         #endif
 
-        /* When MPU wrapper v2 is used, the task's context is stored in TCB and
-         * pxTopOfStack member of TCB points to the context location in TCB. We,
-         * therefore, need to read PSP to find the task's current top of stack. */
-        #define portGET_CURRENT_TOP_OF_STACK( pxCurrentTopOfStack ) { __asm volatile ( "mrs %0, psp"  : "=r" ( pxCurrentTopOfStack ) ); }
-
         /**
          * @brief System call stack.
          */

diff --git a/portable/IAR/ARM_CM23/non_secure/portmacrocommon.h b/portable/IAR/ARM_CM23/non_secure/portmacrocommon.h
@@ -217,11 +217,6 @@ extern void vClearInterruptMask( uint32_t ulMask ) /* __attribute__(( naked )) P
             #error configSYSTEM_CALL_STACK_SIZE must be defined to the desired size of the system call stack in words for using MPU wrappers v2.
         #endif
 
-        /* When MPU wrapper v2 is used, the task's context is stored in TCB and
-         * pxTopOfStack member of TCB points to the context location in TCB. We,
-         * therefore, need to read PSP to find the task's current top of stack. */
-        #define portGET_CURRENT_TOP_OF_STACK( pxCurrentTopOfStack ) { __asm volatile ( "mrs %0, psp"  : "=r" ( pxCurrentTopOfStack ) ); }
-
         /**
          * @brief System call stack.
          */

diff --git a/portable/IAR/ARM_CM23_NTZ/non_secure/portmacrocommon.h b/portable/IAR/ARM_CM23_NTZ/non_secure/portmacrocommon.h
@@ -217,11 +217,6 @@ extern void vClearInterruptMask( uint32_t ulMask ) /* __attribute__(( naked )) P
             #error configSYSTEM_CALL_STACK_SIZE must be defined to the desired size of the system call stack in words for using MPU wrappers v2.
         #endif
 
-        /* When MPU wrapper v2 is used, the task's context is stored in TCB and
-         * pxTopOfStack member of TCB points to the context location in TCB. We,
-         * therefore, need to read PSP to find the task's current top of stack. */
-        #define portGET_CURRENT_TOP_OF_STACK( pxCurrentTopOfStack ) { __asm volatile ( "mrs %0, psp"  : "=r" ( pxCurrentTopOfStack ) ); }
-
         /**
          * @brief System call stack.
          */