risc-v: initialize active_irq during PLIC init

- Initialize all elements active_irq during PLIC init and done't assume
  implicitly that irqInvalid is zero.
- make active_irq hold elements of the type irq_t and not uint32_t.

Signed-off-by: Axel Heider <axel.heider@hensoldt-cyber.de>

src/arch/riscv/machine/hardware.c

@@ -103,7 +103,7 @@ static irq_t getNewActiveIRQ(void)
     return irqInvalid;
 }
 
-static uint32_t active_irq[CONFIG_MAX_NUM_NODES] = { irqInvalid };
+static irq_t active_irq[CONFIG_MAX_NUM_NODES];
 
 
 /**
@@ -267,6 +267,15 @@ BOOT_CODE void initIRQController(void)
 {
     printf("Initializing PLIC...\n");
 
+    /* Initialize active_irq[] properly to stick to the semantics and play safe.
+     * Effectively this is not needed if irqInvalid is zero (which is currently
+     * the case) and the array is in the BSS, that is filled with zeros (which
+     * the a kernel loader is supposed to do and which the ELF-Loader does).
+     */
+    for (word_t i = 0; i < ARRAY_SIZE(active_irq); i++) {
+        active_irq[i] = irqInvalid;
+    }
+
     plic_init_controller();
 }