Add immediate log output for early kernel

src/kernel/log.cpp

@@ -16,29 +16,22 @@ static log::logger g_logger(log_buffer, sizeof(log_buffer));
 
 static const uint8_t level_colors[] = {0x07, 0x07, 0x0f, 0x0b, 0x09};
 
-void
-output_logs()
+static void
+output_log(log::area_t area, log::level severity, const char *message)
 {
-	uint8_t buffer[257];
-	auto *ent = reinterpret_cast<log::logger::entry *>(buffer);
 	auto *cons = console::get();
-
-	while (true) {
-		if(g_logger.get_entry(buffer, sizeof(buffer))) {
-			buffer[ent->bytes] = 0;
-			cons->set_color(level_colors[static_cast<int>(ent->severity)]);
-			cons->printf("%9s %8s: %s\n",
-					g_logger.area_name(ent->area),
-					g_logger.level_name(ent->severity),
-					ent->message);
-			cons->set_color();
-		}
-	}
+	cons->set_color(level_colors[static_cast<int>(severity)]);
+	cons->printf("%9s %8s: %s\n",
+			g_logger.area_name(area),
+			g_logger.level_name(severity),
+			message);
+	cons->set_color();
 }
 
 void init()
 {
 	new (&g_logger) log::logger(log_buffer, sizeof(log_buffer));
+	g_logger.set_immediate(output_log);
 
 #define LOG(name, lvl) \
 	g_logger.register_area(name, name ## _name, log::level ::lvl);

src/kernel/log.h

@@ -11,7 +11,6 @@ namespace logs {
 #undef LOG
 
 void init();
-void output_logs();
 
 } // namespace logs
 

src/kernel/main.cpp

@@ -138,5 +138,4 @@ kernel_main(kernel_args *header)
 	}
 
 	sched->start();
-	logs::output_logs();
 }

src/libraries/kutil/include/kutil/logger.h

@@ -30,6 +30,12 @@ public:
 	/// \arg verbosity What level of logs to print for this area
 	void register_area(area_t area, const char *name, level verbosity);
 
+	/// Callback type for immediate-mode logging
+	typedef void (*immediate)(area_t, level, const char *);
+
+	/// Register an immediate-mode log callback
+	inline void set_immediate(immediate cb) { m_immediate = cb; }
+
 	/// Get the default logger.
 	inline logger & get() { return *s_log; }
 
@@ -85,6 +91,7 @@ private:
 	static const unsigned num_areas = 1 << (sizeof(area_t) * 8);
 	uint8_t m_levels[num_areas / 2];
 	const char *m_names[num_areas];
+	immediate m_immediate;
 
 	uint8_t m_sequence;
 

src/libraries/kutil/logger.cpp

@@ -14,6 +14,7 @@ const char *logger::s_level_names[] = {"", "debug", " info", " warn", "error", "
 
 logger::logger() :
 	m_buffer(nullptr, 0),
+	m_immediate(nullptr),
 	m_sequence(0)
 {
 	memset(&m_levels, 0, sizeof(m_levels));
@@ -23,6 +24,7 @@ logger::logger() :
 
 logger::logger(uint8_t *buffer, size_t size) :
 	m_buffer(buffer, size),
+	m_immediate(nullptr),
 	m_sequence(0)
 {
 	memset(&m_levels, 0, sizeof(m_levels));
@@ -73,6 +75,12 @@ logger::output(level severity, area_t area, const char *fmt, va_list args)
 	header->bytes +=
 		vsnprintf(header->message, sizeof(buffer) - sizeof(entry), fmt, args);
 
+	if (m_immediate) {
+		buffer[header->bytes] = 0;
+		m_immediate(area, severity, header->message);
+		return;
+	}
+
 	uint8_t *out;
 	size_t n = m_buffer.reserve(header->bytes, reinterpret_cast<void**>(&out));
 	if (n < sizeof(entry)) {