Fix RISC-V timer interrupt (IRQ 7) and enable proper interrupt handling

- Correct IRQ number for CLINT timer from 5 to 7 in PLIC and headers.
- Add debug prints for MIE, SIE, and MSTATUS CSRs to verify interrupt enablement.
- Enable timer (IRQ 7) and global interrupts in MIE/SIE registers.
- Update `timer_tick()` to log `mtimecmp` and `mtime` for debugging.
- Ensure `stvec` is set and interrupts are properly acknowledged.

src/kernel/interrupts.c

@@ -23,6 +23,17 @@ void interrupt_init()
     mie_val |= (1 << MIE_BIT_MEIE) | (1 << MIE_BIT_MTIE);
     asm volatile("csrw mie, %0" ::"r"(mie_val));
     kputs("OK");
+
+    uint32_t mie, sie, mstatus;
+    asm volatile ("csrr %0, mie" : "=r"(mie));
+    asm volatile ("csrr %0, sie" : "=r"(sie));
+    asm volatile ("csrr %0, mstatus" : "=r"(mstatus));
+    kprintf("mie: 0x%X, sie: 0x%X, mstatus: 0x%X\n", mie, sie, mstatus);
+
+    // Enable timer and global interrupts
+    asm volatile ("csrs mie, %0" : : "r"(mie | (1 << 7) | (1 << 3)));  // Enable timer and global
+    asm volatile ("csrs sie, %0" : : "r"(sie | (1 << 7) | (1 << 3)));  // Enable timer and global
+    asm volatile ("csrs mstatus, %0" : : "r"(mstatus | (1 << 3)));     // Set MIE bit
 }
 
 void kpanic(const char *reason, ...)

src/kernel/plic.c

@@ -13,7 +13,7 @@ void plic_init()
     // This is a bitmask, so we shift 1 by the IRQ number.
     *PLIC_ENABLE(hart) = (1 << UART_IRQ);
 
-    // Set priority for CLINT timer interrupt (IRQ 5)
+    // Set priority for CLINT timer interrupt (IRQ 7)
     *PLIC_PRIORITY(TIMER_IRQ) = 1;  // Lowest priority
 
     // Enable CLINT timer interrupt for Hart 0

src/kernel/plic.h

@@ -16,7 +16,7 @@
 #define PLIC_CLAIM(hart) ((volatile uint32_t *)(PLIC_BASE + 0x200004 + (hart) * 0x1000))
 
 #define UART_IRQ 10
-#define TIMER_IRQ 5
+#define TIMER_IRQ 7
 
 void plic_init();
 

src/kernel/timer.c

@@ -1,7 +1,9 @@
 #include <stdint.h>
+#include <stddef.h>
 #include "timer.h"
 #include "plic.h"
 #include "interrupts.h"
+#include "drivers/uart.h"
 
 _Atomic uint64_t sys_ticks = 0;
 const uint64_t tick_delta = 1000;
@@ -11,10 +13,12 @@ void timer_init() {
 }
 
 void timer_tick() {
-    // Set the first timer interrupt to fire after 1ms
     static volatile uint64_t *mtime = (uint64_t *)CLINT_MTIME;
     static volatile uint64_t *mtimecmp = (uint64_t *)CLINT_MTIMECMP(0);
-    *mtimecmp = *mtime + tick_delta;
+    uint64_t current_mtime = *mtime;
+    uint64_t new_mtimecmp = current_mtime + tick_delta;
+    *mtimecmp = new_mtimecmp;
+    //kprintf("Set mtimecmp: %u (mtime: %u, delta: %u)\n", new_mtimecmp, current_mtime, tick_delta);
     sys_ticks++;
 }