[uml-devel] patch/RFC: add bypass for "debug" parameter

[Werner A. <we...@al...>]

Since UML ursurps the "debug" parameter, we can't make the kernel
more verbose before user space runs. This patch adds a new option
"kernel" that has the same effect as the original "debug".

Slightly kludgy, but gets the job done :-)

The patch is for 2.6.1 with uml-patch-2.6.1-1.

- Werner

--- linux-2.6.1/arch/um/kernel/tt/tracer.c.orig	Sun Feb  8 18:15:18 2004
+++ linux-2.6.1/arch/um/kernel/tt/tracer.c	Sun Feb  8 18:44:51 2004
@@ -391,10 +391,19 @@
 {
 	char *next;
 
-	debug = 1;
-	*add = 0;
-	if(*line != '=') return(0);
-	line++;
+	if (!strncmp(line, "=kernel", 7)) {
+		*line = 0;
+		if (line[7] != ',')
+			return 0;
+		line += 8;
+		debug = 1;
+	}
+	else {
+		debug = 1;
+		*add = 0;
+		if(*line != '=') return(0);
+		line++;
+	}
 
 	while(line != NULL){
 		next = strchr(line, ',');
@@ -410,10 +419,15 @@
 }
 
 __uml_setup("debug", uml_debug_setup,
-"debug\n"
-"    Starts up the kernel under the control of gdb. See the \n"
-"    kernel debugging tutorial and the debugging session pages\n"
-"    at http://user-mode-linux.sourceforge.net/ for more information.\n\n"
+"debug[=kernel,go,parent]\n"
+"    \"debug=kernel\" changes the kernel log level such that debugging\n"
+"    printks are printed on the console. This is equivalent to the \"debug\"\n"
+"    option in a non-UML kernel. If \"debug=kernel\" is used with other\n"
+"    options, it must be the first option in the list.\n"
+"    The other options (or just plain \"debug\") start up the kernel under\n"
+"    the control of gdb. See the kernel debugging tutorial and the\n"
+"    debugging session pages at http://user-mode-linux.sourceforge.net/\n"
+"    for more information.\n\n"
 );
 
 static int __init uml_debugtrace_setup(char *line, int *add)

-- 
  _________________________________________________________________________
 / Werner Almesberger, Buenos Aires, Argentina     we...@al... /
/_http://www.almesberger.net/____________________________________________/