ThreadX: Interrupt fixes for TX_ENABLE_EXECUTION_CHANGE_NOTIFY

- Must reload register trashed by notify hook function call
- Must ensure PS.WOE is set before using call8
- Remove unused XT_USE_INT_WRAPPER define and associated changes,
  which had a bug in XEA2 usage
- Fix another case where enabling the thread notify hooks for
  call0 ABI corrupted a register

Author: ianstcdns

ports/xtensa/xcc/inc/xtensa_context.h

@@ -373,21 +373,6 @@ XSTRUCT_END(XtExcFrame)
 #endif
 #endif
 
-
-/*
--------------------------------------------------------------------------------
-  This flag is meant for internal use. Have all interrupts be dispatched via a
-  common wrapper, which takes care of doing some OS-specific stuff common to
-  all interrupt handlers. Said stuff cannot safely be handled in the RTOS_ENTER
-  and RTOS_EXIT macros.
--------------------------------------------------------------------------------
-*/
-#if (defined TX_ENABLE_EXECUTION_CHANGE_NOTIFY) || (defined XT_INTEXC_HOOKS)
-#define XT_USE_INT_WRAPPER    1
-#else
-#define XT_USE_INT_WRAPPER    0
-#endif
-
 #if XCHAL_HAVE_XEA2 && (XCHAL_NUM_INTERRUPTS > 32) && (defined XT_USE_SWPRI)
 #error "Software prioritization of interrupts (XT_USE_SWPRI) not supported for XEA2 with > 32 interrupts."
 #endif
@@ -504,12 +489,15 @@ XSTRUCT_END(XtExcFrame)
 
 #ifdef TX_ENABLE_EXECUTION_CHANGE_NOTIFY
     // Call the thread entry function to indicate the thread is executing.
-    // SP should be pointing to a safe region at this point.
+    // SP should be pointing to a safe region at this point. Note that a9
+    // may be trashed by this call, must be reloaded.
 #ifdef __XTENSA_CALL0_ABI__
     call0    _tx_execution_thread_enter
 #else
     call8    _tx_execution_thread_enter
 #endif
+    movi     a9,  _tx_thread_current_ptr        // a9  <- &_tx_thread_current_ptr
+    l32i     a9,  a9, 0                         // a9  <- _tx_thread_current_ptr
 #endif
 
     l32i     a2,  a9, tx_thread_solicited       // a2 = solicited flag

ports/xtensa/xcc/src/tx_thread_schedule.S

@@ -166,9 +166,18 @@ _tx_thread_schedule:
 
     #if (defined(TX_ENABLE_EXECUTION_CHANGE_NOTIFY) || defined(TX_EXECUTION_PROFILE_ENABLE))
     /* Call the thread entry function to indicate the thread is executing. */
+    /* Note a2 may be trashed by this call, must be reloaded. */
     #ifdef __XTENSA_CALL0_ABI__
     call0   _tx_execution_thread_enter
+    movi    a2, _tx_thread_current_ptr
+    l32i    a2, a2, 0
     #else
+    /* Ensure that PS.WOE is set for windowed call */
+    movi    a0, PS_WOE
+    rsr.ps  a3
+    or      a3, a3, a0
+    wsr.ps  a3
+    rsync
     call8   _tx_execution_thread_enter
     #endif
     #endif

ports/xtensa/xcc/src/tx_thread_system_return.S

@@ -83,7 +83,12 @@ _tx_thread_system_return:
 #if (defined(TX_ENABLE_EXECUTION_CHANGE_NOTIFY) || defined(TX_EXECUTION_PROFILE_ENABLE))
     /* Call the thread exit function to indicate the thread is no longer executing. */
 #ifdef __XTENSA_CALL0_ABI__
+    /* Preserve a0 across the call. */
+#if !XCHAL_HAVE_XEA3
+    s32i    a0, sp, 0
+#endif
     call0   _tx_execution_thread_exit
+    l32i    a0, sp, 0
 #else
     call8   _tx_execution_thread_exit
 #endif

ports/xtensa/xcc/src/xtensa_intr.c

@@ -93,7 +93,7 @@ typedef struct xt_handler_table_entry {
     void * arg;
 } xt_handler_table_entry;
 
-#if (XT_USE_INT_WRAPPER || XCHAL_HAVE_XEA3)
+#if XCHAL_HAVE_XEA3
 extern xt_handler_table_entry _xt_interrupt_table[XCHAL_NUM_INTERRUPTS + 1];
 #else
 extern xt_handler_table_entry _xt_interrupt_table[XCHAL_NUM_INTERRUPTS];
@@ -131,7 +131,7 @@ xt_handler xt_set_interrupt_handler(uint32_t n, xt_handler f, void * arg)
     }
 #endif
 
-#if (XT_USE_INT_WRAPPER || XCHAL_HAVE_XEA3)
+#if XCHAL_HAVE_XEA3
     entry = _xt_interrupt_table + n + 1;
 #else
     entry = _xt_interrupt_table + n;

ports/xtensa/xcc/src/xtensa_intr_asm.S

@@ -112,9 +112,6 @@ _xt_interrupt_table:
 #if XCHAL_HAVE_XEA3
     .word   xt_interrupt_wrapper
     .word   0
-#elif XT_USE_INT_WRAPPER
-    .word   0
-    .word   0
 #endif
 
     .set    i, 0

ports/xtensa/xcc/src/xtensa_vectors.S

@@ -150,7 +150,10 @@
     .macro  call_exec_isr_entry_fn
     #ifdef TX_ENABLE_EXECUTION_CHANGE_NOTIFY
     #ifdef __XTENSA_CALL0_ABI__
+    /* Preserve a2 across the call, a12 is callee-saved for call0 ABI. */
+    mov     a12, a2
     call0   _tx_execution_isr_enter
+    mov     a2, a12
     #else
     call4   _tx_execution_isr_enter
     #endif