implements halt using WFI if hartid!=0 and multicore

env/riscv_vp/init.c

@@ -103,7 +103,10 @@ void __attribute__((weak)) _init() {
     while(i < NUM_INTERRUPTS) {
         localISR[i++] = default_handler;
     }
-
+#endif
+#if defined(NUM_HARTS) && NUM_HARTS > 1
+    for(int i = 1; i < NUM_HARTS; ++i)
+        set_aclint_msip(aclint, i, 1);
 #endif
 }
 

env/start.S

@@ -30,11 +30,14 @@ _start:
 2:
     la t0, trap_entry
     csrw mtvec, t0
-#ifdef HARTX_WAIT4WFI
+#if defined(NUM_HARTS) && NUM_HARTS>1
 	/* block other cores until hart 0 has finished initialization */
 	csrr  t0, mhartid 
 	beqz t0, hart0_init
+	/* enable MSI locally */
+	csrwi mie, 0x8 
 	wfi
+	csrw mie, zero
 	j hartx_start
 hart0_init:
 #endif