Staging: add TAINT_CRAP for all drivers/staging code

We need to add a flag for all code that is in the drivers/staging/
directory to prevent all other kernel developers from worrying about
issues here, and to notify users that the drivers might not be as good
as they are normally used to.

Based on code from Andreas Gruenbacher and Jeff Mahoney to provide a
TAINT flag for the support level of a kernel module in the Novell
enterprise kernel release.

This is the kernel portion of this feature, the ability for the flag to
be set needs to be done in the build process and will happen in a
follow-up patch.

Cc: Andreas Gruenbacher <agruen@suse.de>
Cc: Jeff Mahoney <jeffm@suse.de>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

Documentation/sysctl/kernel.txt

@@ -369,4 +369,5 @@ can be ORed together:
   2 - A module was force loaded by insmod -f.
       Set by modutils >= 2.4.9 and module-init-tools.
   4 - Unsafe SMP processors: SMP with CPUs not designed for SMP.
+ 64 - A module from drivers/staging was loaded.
 

include/linux/kernel.h

@@ -260,6 +260,7 @@ extern enum system_states {
 #define TAINT_DIE			(1<<7)
 #define TAINT_OVERRIDDEN_ACPI_TABLE	(1<<8)
 #define TAINT_WARN			(1<<9)
+#define TAINT_CRAP			(1<<10)
 
 extern void dump_stack(void) __cold;
 

kernel/module.c

@@ -1806,6 +1806,7 @@ static noinline struct module *load_module(void __user *umod,
 	Elf_Ehdr *hdr;
 	Elf_Shdr *sechdrs;
 	char *secstrings, *args, *modmagic, *strtab = NULL;
+	char *staging;
 	unsigned int i;
 	unsigned int symindex = 0;
 	unsigned int strindex = 0;
@@ -1960,6 +1961,14 @@ static noinline struct module *load_module(void __user *umod,
 		goto free_hdr;
 	}
 
+	staging = get_modinfo(sechdrs, infoindex, "staging");
+	if (staging) {
+		add_taint_module(mod, TAINT_CRAP);
+		printk(KERN_WARNING "%s: module is from the staging directory,"
+		       " the quality is unknown, you have been warned.\n",
+		       mod->name);
+	}
+
 	/* Now copy in args */
 	args = strndup_user(uargs, ~0UL >> 1);
 	if (IS_ERR(args)) {
@@ -2556,6 +2565,8 @@ static char *module_flags(struct module *mod, char *buf)
 			buf[bx++] = 'P';
 		if (mod->taints & TAINT_FORCED_MODULE)
 			buf[bx++] = 'F';
+		if (mod->taints & TAINT_CRAP)
+			buf[bx++] = 'C';
 		/*
 		 * TAINT_FORCED_RMMOD: could be added.
 		 * TAINT_UNSAFE_SMP, TAINT_MACHINE_CHECK, TAINT_BAD_PAGE don't

kernel/panic.c

@@ -155,6 +155,7 @@ EXPORT_SYMBOL(panic);
  *  'U' - Userspace-defined naughtiness.
  *  'A' - ACPI table overridden.
  *  'W' - Taint on warning.
+ *  'C' - modules from drivers/staging are loaded.
  *
  *	The string is overwritten by the next call to print_taint().
  */
@@ -163,7 +164,7 @@ const char *print_tainted(void)
 {
 	static char buf[20];
 	if (tainted) {
-		snprintf(buf, sizeof(buf), "Tainted: %c%c%c%c%c%c%c%c%c%c",
+		snprintf(buf, sizeof(buf), "Tainted: %c%c%c%c%c%c%c%c%c%c%c",
 			tainted & TAINT_PROPRIETARY_MODULE ? 'P' : 'G',
 			tainted & TAINT_FORCED_MODULE ? 'F' : ' ',
 			tainted & TAINT_UNSAFE_SMP ? 'S' : ' ',
@@ -173,7 +174,8 @@ const char *print_tainted(void)
 			tainted & TAINT_USER ? 'U' : ' ',
 			tainted & TAINT_DIE ? 'D' : ' ',
 			tainted & TAINT_OVERRIDDEN_ACPI_TABLE ? 'A' : ' ',
-			tainted & TAINT_WARN ? 'W' : ' ');
+			tainted & TAINT_WARN ? 'W' : ' ',
+			tainted & TAINT_CRAP ? 'C' : ' ');
 	}
 	else
 		snprintf(buf, sizeof(buf), "Not tainted");