Better panic, with PANIC macro

kern/libkern/panic.c

@@ -1,8 +1,18 @@
+#include "stdbool.h"
+#include <mini-printf.h>
+#include <stdarg.h>
+#include <stddef.h>
+#include <stdio.h>
 #include <uart.h>
-volatile int panicked;
 
-void panic(char *s) {
-    panicked = 1;
-    uart_puts(s);
-    while (1);
+volatile int panicked = false;
+
+__attribute__((visibility("hidden")))
+void __panic(const char *restrict fmt, ...) {
+    va_list ap;
+    va_start(ap, fmt);
+    (void)mini_vpprintf(stdout_puts, NULL, fmt, ap);
+    va_end(ap);
+    panicked = true;
+    while (true) asm volatile("wfi");
 }

kern/libkern/panic.h

@@ -1,6 +1,8 @@
 #ifndef KERNEL_PANIC_H
 #define KERNEL_PANIC_H
 
-void panic(char *s);
+#define PANIC(fmt, ...) __panic("[%s:%d %s] \n" fmt, __FILE__, __LINE__, __func__)
+
+void __panic(const char *restrict fmt, ...);
 
 #endif