Merge branch 'feature/freertos_interrupt_backtrace_opt' into 'master'

freertos: introduce CONFIG_FREERTOS_INTERRUPT_BACKTRACE

See merge request !1167

components/freertos/Kconfig

@@ -94,6 +94,18 @@ config FREERTOS_WATCHPOINT_END_OF_STACK
         When this watchpoint is hit, gdb will stop with a SIGTRAP message. When no OCD is attached, esp-idf
         will panic on an unhandled debug exception.
 
+config FREERTOS_INTERRUPT_BACKTRACE
+    bool "Enable backtrace from interrupt to task context"
+    default y
+    help
+        If this option is enabled, interrupt stack frame will be modified to
+        point to the code of the interrupted task as its return address.
+        This helps the debugger (or the panic handler) show a backtrace from
+        the interrupt to the task which was interrupted. This also works for
+        nested interrupts: higer level interrupt stack can be traced back to the
+        lower level interrupt.
+        This option adds 4 instructions to the interrupt dispatching code.
+
 config FREERTOS_THREAD_LOCAL_STORAGE_POINTERS
     int "Number of thread local storage pointers"
     range 1 256

components/freertos/xtensa_vectors.S

@@ -104,7 +104,9 @@ SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 .extern pxCurrentTCB
 
 /* Enable stack backtrace across exception/interrupt - see below */
-#define XT_DEBUG_BACKTRACE    0
+#ifdef CONFIG_FREERTOS_INTERRUPT_BACKTRACE
+#define XT_DEBUG_BACKTRACE    1
+#endif
 
 
 /*
@@ -195,7 +197,7 @@ SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
        It does take a few more instructions, so undef XT_DEBUG_BACKTRACE
        if you want to save the cycles.
     */
-    #if XT_DEBUG_BACKTRACE
+    #ifdef XT_DEBUG_BACKTRACE
     #ifndef __XTENSA_CALL0_ABI__
     rsr     a0, EPC_1 + \level - 1          /* return address */
     movi    a4, 0xC0000000                  /* constant with top 2 bits set (call size) */