all: add console and logging machinery

src/kern/init.zig

@@ -13,6 +13,7 @@ pub fn init(boot_info: *pl.BootInfo) linksection(r.init) void {
     ki.impl.early_init();
     std.log.info("Welcome to the machine", .{});
     pl.early_init(boot_info);
+    ki.log.init();
     ki.cpu.init_cpu(0);
     ki.turnstile.init_turnstiles();
     ki.shootdown.init();

src/kern/log.zig

@@ -39,6 +39,22 @@ const avg_msg_size_bits = 5;
 
 pub var ringbuffer = ki.log_ring.RingBuffer(config.log_buffer_shift, avg_msg_size_bits).init();
 
+// Initialize manually because we need this ASAP.
+pub var event: ke.Event = .{
+    .hdr = .{
+        .lock = .init(),
+        .signaled = 0,
+        .type = .Notification,
+        .waitblocks = .{
+            .head = .{ .next = &event.hdr.waitblocks.head, .prev = &event.hdr.waitblocks.head },
+        },
+    },
+};
+
+pub fn init() void {
+    event.init(.Notification);
+}
+
 pub fn log(
     comptime level: std.log.Level,
     comptime scope: @EnumLiteral(),
@@ -63,9 +79,9 @@ pub fn log(
 
     ringbuffer.publish(res);
 
-    // TODO: for now, we print to the platform's debug output immediately.
-    // In the future, we should instead set an event that would get triggered in Ex,
-    // which would consume the ringbuffer from multiple consoles in a separate thread.
+    // Signal whomever is waiting on logs to get published.
+    event.signal();
+
     var writer = DebugWriter.init();
 
     const ipl = out_lock.acquire_at(.High);

src/kern/root.zig

@@ -68,6 +68,8 @@ pub const wait = struct {
 pub const log = struct {
     pub const register_console = p.log.register_console;
     pub const log = p.log.log;
+    pub const ringbuffer = &p.log.ringbuffer;
+    pub const event = &p.log.event;
 };
 
 pub const cpu = struct {