kernel: add basic console registration system and printk()

arch/x86_64/include/socks/machine/console.h

@@ -1,7 +0,0 @@
-#ifndef SOCKS_X86_64_CONSOLE_H_
-#define SOCKS_X86_64_CONSOLE_H_
-
-extern void ml_console_init(void);
-extern void ml_console_putchar(int c);
-
-#endif

arch/x86_64/include/socks/machine/cpu.h

@@ -3,6 +3,8 @@
 
 #include <socks/machine/_gdt.h>
 
+#define ml_halt_cpu() asm volatile("cli;hlt")
+
 typedef struct ml_cpu_block {
 	struct gdt c_gdt;
 	struct gdt_ptr c_gdt_ptr;

arch/x86_64/include/socks/machine/vgacon.h

@@ -0,0 +1,6 @@
+#ifndef SOCKS_X86_64_CONSOLE_H_
+#define SOCKS_X86_64_CONSOLE_H_
+
+extern void vgacon_init(void);
+
+#endif

arch/x86_64/init.c

@@ -1,4 +1,5 @@
 #include <socks/machine/cpu.h>
+#include <socks/machine/vgacon.h>
 
 static ml_cpu_block g_bootstrap_cpu = {0};
 
@@ -11,5 +12,6 @@ static void bootstrap_cpu_init(void)
 int ml_init(uintptr_t arg)
 {
 	bootstrap_cpu_init();
+	vgacon_init();
 	return 0;
 }

arch/x86_64/vgacon.c

@@ -1,6 +1,8 @@
 #include <socks/libc/string.h>
 #include <socks/libc/ctype.h>
 #include <socks/machine/ports.h>
+#include <socks/console.h>
+#include <socks/printk.h>
 #include <stdint.h>
 
 #define VGA_PORT_CMD		0x3D4
@@ -36,15 +38,6 @@ static void move_vga_cursor(unsigned int x, unsigned int y)
 	outportb(VGA_PORT_DATA, (uint8_t)((offset >> 8) & 0xFF));
 }
 
-void ml_console_init(void)
-{
-	g_console_cursor_xpos = 0;
-	g_console_cursor_ypos = 5;
-
-	init_vga_cursor();
-	move_vga_cursor(g_console_cursor_xpos, g_console_cursor_ypos);
-}
-
 static void scroll_display()
 {
 	uint16_t *src = g_console_fb + k_console_width;
@@ -79,7 +72,7 @@ static void handle_ctrl(int c)
 	move_vga_cursor(g_console_cursor_xpos, g_console_cursor_ypos);
 }
 
-void ml_console_putchar(int c)
+static void vgacon_putchar(int c)
 {
 	if (iscntrl(c)) {
 		handle_ctrl(c);
@@ -103,3 +96,29 @@ void ml_console_putchar(int c)
 
 	move_vga_cursor(g_console_cursor_xpos, g_console_cursor_ypos);
 }
+
+static void vgacon_write(console_t *con, const char *s, unsigned int len)
+{
+	for (unsigned int i = 0; i < len; i++) {
+		vgacon_putchar(s[i]);
+	}
+}
+
+static console_t vgacon = {
+	.c_name = "vgacon",
+	.c_flags = CON_BOOT,
+	.c_write = vgacon_write,
+	.c_lock = SPIN_LOCK_INIT,
+};
+
+void vgacon_init(void)
+{
+	g_console_cursor_xpos = 0;
+	g_console_cursor_ypos = 5;
+
+	init_vga_cursor();
+	move_vga_cursor(g_console_cursor_xpos, g_console_cursor_ypos);
+
+	console_register(&vgacon);
+	early_printk_init(&vgacon);
+}

include/socks/console.h

@@ -1,7 +1,29 @@
 #ifndef SOCKS_CONSOLE_H_
 #define SOCKS_CONSOLE_H_
 
-extern void console_init(void);
-extern void console_putchar(int c);
+#include <socks/queue.h>
+#include <socks/locks.h>
+#include <socks/status.h>
+
+typedef enum console_flags {
+	CON_BOOT = 0x01u,
+} console_flags_t;
+
+typedef struct console {
+	char c_name[16];
+	console_flags_t c_flags;
+	spin_lock_t c_lock;
+
+	void (*c_write)(struct console *, const char *, unsigned int);
+	int (*c_read)(struct console *, char *, unsigned int);
+
+	queue_entry_t c_list;
+} console_t;
+
+extern kern_status_t console_register(console_t *con);
+extern kern_status_t console_unregister(console_t *con);
+
+extern void console_write(console_t *con, const char *s, unsigned int len);
+extern int console_read(console_t *con, char *s, unsigned int len);
 
 #endif

include/socks/printk.h

@@ -1,6 +1,9 @@
 #ifndef SOCKS_PRINTK_H_
 #define SOCKS_PRINTK_H_
 
+#include <socks/console.h>
+
+extern void early_printk_init(console_t *con);
 extern int printk(const char *format, ...);
 
 #endif

include/socks/status.h

@@ -3,7 +3,8 @@
 
 typedef unsigned int kern_status_t;
 
-#define KERN_OK			(0)
-#define KERN_ERR_UNIMPLEMENTED	(1)
+#define KERN_OK            (0)
+#define KERN_UNIMPLEMENTED (1)
+#define KERN_NAME_EXISTS   (2)
 
 #endif

init/main.c

@@ -2,12 +2,15 @@
 #include <socks/init.h>
 #include <socks/printk.h>
 #include <socks/machine/init.h>
+#include <socks/machine/cpu.h>
+
+extern unsigned long get_rflags(void);
 
 void kernel_init(uintptr_t arg)
 {
 	ml_init(arg);
 
-	for (int i = 0; i < 8; i++) {
-		printk("Line %d\n", i);
-	}
+	printk("hello, world!");
+
+	ml_halt_cpu();
 }

kernel/console.c

@@ -1,12 +1,52 @@
 #include <socks/console.h>
-#include <socks/machine/console.h>
+#include <socks/queue.h>
+#include <socks/locks.h>
+#include <socks/libc/string.h>
 
-void console_init(void)
+static queue_t consoles;
+static spin_lock_t consoles_lock = SPIN_LOCK_INIT;
+
+kern_status_t console_register(console_t *con)
 {
-	ml_console_init();
+	unsigned long flags;
+	spin_lock_irqsave(&consoles_lock, &flags);
+
+	queue_foreach (console_t, cur, &consoles, c_list) {
+		if (!strcmp(cur->c_name, con->c_name)) {
+			spin_unlock_irqrestore(&consoles_lock, flags);
+			return KERN_NAME_EXISTS;
+		}
+	}
+
+	queue_push_back(&consoles, &con->c_list);
+	spin_unlock_irqrestore(&consoles_lock, flags);
+	return KERN_OK;
 }
 
-void console_putchar(int c)
+kern_status_t console_unregister(console_t *con)
 {
-	ml_console_putchar(c);
+	unsigned long flags;
+	spin_lock_irqsave(&consoles_lock, &flags);
+
+	queue_delete(&consoles, &con->c_list);
+	
+	spin_unlock_irqrestore(&consoles_lock, flags);
+	return KERN_OK;
+}
+
+void console_write(console_t *con, const char *s, unsigned int len)
+{
+	if (con->c_write) {
+		con->c_write(con, s, len);
+	}
+}
+
+int console_read(console_t *con, char *s, unsigned int len)
+{
+	int ret = -1;
+	if (con->c_read) {
+		ret = con->c_read(con, s, len);
+	}
+
+	return ret;
 }

kernel/printk.c

@@ -1,10 +1,74 @@
+#include <socks/printk.h>
+#include <socks/locks.h>
+#include <socks/console.h>
+#include <socks/libc/stdio.h>
+#include <stdarg.h>
 
 #define LOG_BUFFER_SIZE 0x40000
+#define LOG_MSG_SIZE    0x100
+
+static console_t *early_console = NULL;
+
+static spin_lock_t log_buffer_lock = SPIN_LOCK_INIT;
 
 static char log_buffer[LOG_BUFFER_SIZE] = {0};
+/* index of the last character in log_buffer that has been written
+   to the console */
+static unsigned int log_buffer_readp = 0;
+/* index of the last character in log_buffer that has been logged
+   (but not necessarily written to the console) */
+static unsigned int log_buffer_writep = 0;
+
+static void flush_log_buffer(void)
+{
+	if (!early_console) {
+		return;
+	}
+	
+	console_write(early_console, log_buffer + log_buffer_readp, log_buffer_writep - log_buffer_readp);
+	log_buffer_readp = log_buffer_writep;
+}
+
+static void save_log_message(const char *msg)
+{
+	unsigned int i = 0;
+	while (1) {
+		if (log_buffer_writep == LOG_BUFFER_SIZE - 1) {
+			log_buffer[log_buffer_writep] = '\0';
+			break;
+		}
+
+		if (msg[i] == '\0') {
+			break;
+		}
+				   
+		log_buffer[log_buffer_writep++] = msg[i++];
+	}
+}
+
+void early_printk_init(console_t *con)
+{
+	early_console = con;
+}
 
 int printk(const char *format, ...)
 {
-	(void)log_buffer;
-	return 0;
+	char msg[LOG_MSG_SIZE];
+
+	va_list arg;
+	va_start(arg, format);
+        int len = vsnprintf(msg, sizeof msg - 1, format, arg);
+	va_end(arg);
+
+	msg[len] = '\n';
+	msg[len + 1] = '\0';
+
+	unsigned long flags;
+	spin_lock_irqsave(&log_buffer_lock, &flags);
+	save_log_message(msg);
+	spin_unlock_irqrestore(&log_buffer_lock, flags);
+
+	flush_log_buffer();
+	
+        return 0;
 }