From 6e68d940806c6f7b2bca5134a15b7d88e97678a5 Mon Sep 17 00:00:00 2001
From: Matthias Kruk <m@m10k.eu>
Date: Tue, 31 Dec 2019 15:00:34 +0900
Subject: [PATCH] Disable output from dbg_printf() once the init process has
 been spawned

---
 kernel/arch/debug.c    | 11 +++++++++++
 kernel/core/main.c     | 10 +++++++++-
 kernel/include/debug.h |  1 +
 3 files changed, 21 insertions(+), 1 deletion(-)

diff --git a/kernel/arch/debug.c b/kernel/arch/debug.c
index 5775006..68cf0f2 100644
--- a/kernel/arch/debug.c
+++ b/kernel/arch/debug.c
@@ -58,6 +58,7 @@ static const char nullstr[] = "(null)";
 static u16_t* const vga_buffer = VGA_BUFFER_ADDR;
 static u16_t vga_attrs = VGA_FONT(VGA_LIGHT_GRAY) | VGA_BACKGROUND(VGA_BLACK);
 static i32_t vga_offset = VGA_BUFFER_SIZE;
+static int _early_printf_disable = 0;
 
 #define VGA_SET_FONT(c)         vga_attrs = (vga_attrs & 0xf0ff) | VGA_FONT(c)
 #define VGA_SET_BACKGROUND(c)   vga_attrs = (vga_attrs & 0x0fff) | VGA_BACKGROUND(c)
@@ -158,6 +159,12 @@ static void _putchar(int c)
     return;
 }
 
+void dbg_printf_disable(void)
+{
+	_early_printf_disable = 1;
+	return;
+}
+
 int dbg_printf(const char *format, ...)
 {
     int n;
@@ -169,6 +176,10 @@ int dbg_printf(const char *format, ...)
     int pad;
     const char *fmt;
 
+	if(_early_printf_disable) {
+		return(-1);
+	}
+
     #define MODE_NORMAL 0
     #define MODE_CONV   1
     #define FLAG_SIGN   (1 << 31)
diff --git a/kernel/core/main.c b/kernel/core/main.c
index 96a016b..8bf0c9d 100644
--- a/kernel/core/main.c
+++ b/kernel/core/main.c
@@ -141,12 +141,13 @@ static void _init(void)
 		/* FIXME: Handle error */
 	}
 
+	#if 0
 	struct cxmsg msg;
     char *hw = "Hello, world\n";
 
 	memcpy(msg.cm_data, hw, 13);
 	cxsendrecv(vgapid, &msg);
-
+	#endif
 	wait(NULL);
 
 	return;
@@ -240,6 +241,13 @@ int corax(void *mb_info, u32_t magic)
 		PANIC("Could not spawn init process\n");
 	}
 
+	/*
+	 * Disable early printf - all further output should
+	 * be printed through the VGA process that is spawned
+	 * by init.
+	 */
+	dbg_printf_disable();
+
 	sched_tick();
 
 	dbg_printf("This should not get printed\n");
diff --git a/kernel/include/debug.h b/kernel/include/debug.h
index d642963..b03c3dc 100644
--- a/kernel/include/debug.h
+++ b/kernel/include/debug.h
@@ -30,5 +30,6 @@ i64_t _i64mod(i64_t, i64_t);
 
 int dbg_printf(const char*, ...);
 void dbg_panic(const char*, const char*, i32_t, const char*);
+void dbg_printf_disable(void);
 
 #endif /* __DEBUG_H */
-- 
2.47.3