1 files changed, 41 insertions, 0 deletions

diff --git a/src/kernel/printk.c b/src/kernel/printk.c
new file mode 100644
index 0000000..0daa097
--- /dev/null
+++ b/src/kernel/printk.c
@@ -0,0 +1,41 @@
+/*
+ *  linux/kernel/printk.c
+ *
+ *  (C) 1991  Linus Torvalds
+ */
+
+/*
+ * When in kernel-mode, we cannot use printf, as fs is liable to
+ * point to 'interesting' things. Make a printf with fs-saving, and
+ * all is well.
+ */
+#include <stdarg.h>
+#include <stddef.h>
+
+#include <linux/kernel.h>
+
+static char buf[1024];
+
+extern int vsprintf(char * buf, const char * fmt, va_list args);
+
+int printk(const char *fmt, ...)
+{
+        va_list args;
+        int i;
+
+        va_start(args, fmt);
+        i=vsprintf(buf,fmt,args);
+        va_end(args);
+        __asm__("push %%fs\n\t"
+                "push %%ds\n\t"
+                "pop %%fs\n\t"
+                "pushl %0\n\t"
+                "pushl $buf\n\t"
+                "pushl $0\n\t"
+                "call tty_write\n\t"
+                "addl $8,%%esp\n\t"
+                "popl %0\n\t"
+                "pop %%fs"
+                ::"r" (i):"ax","cx","dx");
+        return i;
+}