Merge branch 'bugfix/xtensa_freertos_16B_aligned' into 'master'

FreeRTOS: Make the default stack alignment 16 for Xtensa

Closes IDF-3604

See merge request espressif/esp-idf!21040

components/freertos/FreeRTOS-Kernel-SMP/portable/riscv/port.c

@@ -44,6 +44,8 @@
 #include "esp_gdbstub.h"
 #endif // CONFIG_ESP_SYSTEM_GDBSTUB_RUNTIME
 
+_Static_assert(portBYTE_ALIGNMENT == 16, "portBYTE_ALIGNMENT must be set to 16");
+
 /* ---------------------------------------------------- Variables ------------------------------------------------------
  *
  * ------------------------------------------------------------------------------------------------------------------ */
@@ -703,13 +705,17 @@ StackType_t *pxPortInitialiseStack(StackType_t *pxTopOfStack, TaskFunction_t pxC
     */
 
     UBaseType_t uxStackPointer = (UBaseType_t)pxTopOfStack;
+    configASSERT((uxStackPointer & portBYTE_ALIGNMENT_MASK) == 0);
 
     // Initialize GCC TLS area
     uint32_t threadptr_reg_init;
     uxStackPointer = uxInitialiseStackTLS(uxStackPointer, &threadptr_reg_init);
+    configASSERT((uxStackPointer & portBYTE_ALIGNMENT_MASK) == 0);
 
     // Initialize the starting interrupt stack frame
     uxStackPointer = uxInitialiseStackFrame(uxStackPointer, pxCode, pvParameters, threadptr_reg_init);
+    configASSERT((uxStackPointer & portBYTE_ALIGNMENT_MASK) == 0);
+
     // Return the task's current stack pointer address which should point to the starting interrupt stack frame
     return (StackType_t *)uxStackPointer;
     //TODO: IDF-2393

components/freertos/FreeRTOS-Kernel-SMP/portable/xtensa/include/freertos/portmacro.h

@@ -72,7 +72,7 @@ typedef uint32_t TickType_t;
 #define portCRITICAL_NESTING_IN_TCB     1
 #define portSTACK_GROWTH                ( -1 )
 #define portTICK_PERIOD_MS              ( ( TickType_t ) 1000 / configTICK_RATE_HZ )
-#define portBYTE_ALIGNMENT              4
+#define portBYTE_ALIGNMENT              16    // Xtensa Windowed ABI requires the stack pointer to always be 16-byte aligned. See "isa_rm.pdf 8.1.1 Windowed Register Usage and Stack Layout"
 #define portNOP()                       XT_NOP()    //Todo: Check if XT_NOP exists
 
 /* ---------------------------------------------- Forward Declarations -------------------------------------------------

components/freertos/FreeRTOS-Kernel-SMP/portable/xtensa/port.c

@@ -50,6 +50,8 @@
 #include "hal/systimer_ll.h"
 #endif // CONFIG_FREERTOS_SYSTICK_USES_SYSTIMER
 
+_Static_assert(portBYTE_ALIGNMENT == 16, "portBYTE_ALIGNMENT must be set to 16");
+
 /*
 OS state variables
 */
@@ -884,18 +886,23 @@ StackType_t * pxPortInitialiseStack( StackType_t * pxTopOfStack,
     */
 
     UBaseType_t uxStackPointer = (UBaseType_t)pxTopOfStack;
+    configASSERT((uxStackPointer & portBYTE_ALIGNMENT_MASK) == 0);
 
 #if XCHAL_CP_NUM > 0
     // Initialize the coprocessor save area
     uxStackPointer = uxInitialiseStackCPSA(uxStackPointer);
+    configASSERT((uxStackPointer & portBYTE_ALIGNMENT_MASK) == 0);
 #endif /* XCHAL_CP_NUM > 0 */
 
     // Initialize the GCC TLS area
     uint32_t threadptr_reg_init;
     uxStackPointer = uxInitialiseStackTLS(uxStackPointer, &threadptr_reg_init);
+    configASSERT((uxStackPointer & portBYTE_ALIGNMENT_MASK) == 0);
 
     // Initialize the starting interrupt stack frame
     uxStackPointer = uxInitialiseStackFrame(uxStackPointer, pxCode, pvParameters, threadptr_reg_init);
+    configASSERT((uxStackPointer & portBYTE_ALIGNMENT_MASK) == 0);
+
     // Return the task's current stack pointer address which should point to the starting interrupt stack frame
     return (StackType_t *)uxStackPointer;
 }

components/freertos/FreeRTOS-Kernel/portable/riscv/port.c

@@ -57,7 +57,7 @@
 #include "port_systick.h"
 #include "esp_memory_utils.h"
 
-
+_Static_assert(portBYTE_ALIGNMENT == 16, "portBYTE_ALIGNMENT must be set to 16");
 
 /* ---------------------------------------------------- Variables ------------------------------------------------------
  *
@@ -284,13 +284,17 @@ StackType_t *pxPortInitialiseStack(StackType_t *pxTopOfStack, TaskFunction_t pxC
     */
 
     UBaseType_t uxStackPointer = (UBaseType_t)pxTopOfStack;
+    configASSERT((uxStackPointer & portBYTE_ALIGNMENT_MASK) == 0);
 
     // Initialize GCC TLS area
     uint32_t threadptr_reg_init;
     uxStackPointer = uxInitialiseStackTLS(uxStackPointer, &threadptr_reg_init);
+    configASSERT((uxStackPointer & portBYTE_ALIGNMENT_MASK) == 0);
 
     // Initialize the starting interrupt stack frame
     uxStackPointer = uxInitialiseStackFrame(uxStackPointer, pxCode, pvParameters, threadptr_reg_init);
+    configASSERT((uxStackPointer & portBYTE_ALIGNMENT_MASK) == 0);
+
     // Return the task's current stack pointer address which should point to the starting interrupt stack frame
     return (StackType_t *)uxStackPointer;
     //TODO: IDF-2393

components/freertos/FreeRTOS-Kernel/portable/xtensa/include/freertos/portmacro.h

@@ -139,7 +139,7 @@ typedef uint32_t TickType_t;
 #define portCRITICAL_NESTING_IN_TCB     0
 #define portSTACK_GROWTH                ( -1 )
 #define portTICK_PERIOD_MS              ( ( TickType_t ) 1000 / configTICK_RATE_HZ )
-#define portBYTE_ALIGNMENT              4
+#define portBYTE_ALIGNMENT              16    // Xtensa Windowed ABI requires the stack pointer to always be 16-byte aligned. See "isa_rm.pdf 8.1.1 Windowed Register Usage and Stack Layout"
 #define portTICK_TYPE_IS_ATOMIC         1
 #define portNOP()                       XT_NOP()
 

components/freertos/FreeRTOS-Kernel/portable/xtensa/port.c

@@ -78,6 +78,8 @@
 #include "esp_cpu.h"
 #include "esp_memory_utils.h"
 
+_Static_assert(portBYTE_ALIGNMENT == 16, "portBYTE_ALIGNMENT must be set to 16");
+
 _Static_assert(tskNO_AFFINITY == CONFIG_FREERTOS_NO_AFFINITY, "incorrect tskNO_AFFINITY value");
 
 
@@ -415,20 +417,24 @@ StackType_t *pxPortInitialiseStack(StackType_t *pxTopOfStack, TaskFunction_t pxC
     - All stack areas are aligned to 16 byte boundary
     - We use UBaseType_t for all of stack area initialization functions for more convenient pointer arithmetic
     */
-
     UBaseType_t uxStackPointer = (UBaseType_t)pxTopOfStack;
-
+    // Make sure the incoming stack pointer is aligned on 16
+    configASSERT((uxStackPointer & portBYTE_ALIGNMENT_MASK) == 0);
 #if XCHAL_CP_NUM > 0
     // Initialize the coprocessor save area
     uxStackPointer = uxInitialiseStackCPSA(uxStackPointer);
+    // Each allocated section on the stack must have a size aligned on 16
+    configASSERT((uxStackPointer & portBYTE_ALIGNMENT_MASK) == 0);
 #endif /* XCHAL_CP_NUM > 0 */
 
     // Initialize the GCC TLS area
     uint32_t threadptr_reg_init;
     uxStackPointer = uxInitialiseStackTLS(uxStackPointer, &threadptr_reg_init);
+    configASSERT((uxStackPointer & portBYTE_ALIGNMENT_MASK) == 0);
 
     // Initialize the starting interrupt stack frame
     uxStackPointer = uxInitialiseStackFrame(uxStackPointer, pxCode, pvParameters, threadptr_reg_init);
+    configASSERT((uxStackPointer & portBYTE_ALIGNMENT_MASK) == 0);
     // Return the task's current stack pointer address which should point to the starting interrupt stack frame
     return (StackType_t *)uxStackPointer;
 }