taint: consolidate documentation

This consolidates the taint bit documentation into a single place with
both numeric and letter values.  Additionally adds the missing TAINT_AUX
documentation.

Link: http://lkml.kernel.org/r/1519084390-43867-3-git-send-email-keescook@chromium.org
Signed-off-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Documentation/sysctl/kernel.txt

@@ -964,32 +964,33 @@ detect a hard lockup condition.
 
 tainted:
 
-Non-zero if the kernel has been tainted.  Numeric values, which
-can be ORed together:
-
-   1 - A module with a non-GPL license has been loaded, this
-       includes modules with no license.
-       Set by modutils >= 2.4.9 and module-init-tools.
-   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.
-   8 - A module was forcibly unloaded from the system by rmmod -f.
-  16 - A hardware machine check error occurred on the system.
-  32 - A bad page was discovered on the system.
-  64 - The user has asked that the system be marked "tainted".  This
-       could be because they are running software that directly modifies
-       the hardware, or for other reasons.
- 128 - The system has died.
- 256 - The ACPI DSDT has been overridden with one supplied by the user
-        instead of using the one provided by the hardware.
- 512 - A kernel warning has occurred.
-1024 - A module from drivers/staging was loaded.
-2048 - The system is working around a severe firmware bug.
-4096 - An out-of-tree module has been loaded.
-8192 - An unsigned module has been loaded in a kernel supporting module
-       signature.
-16384 - A soft lockup has previously occurred on the system.
-32768 - The kernel has been live patched.
+Non-zero if the kernel has been tainted. Numeric values, which can be
+ORed together. The letters are seen in "Tainted" line of Oops reports.
+
+     1 (P):  A module with a non-GPL license has been loaded, this
+             includes modules with no license.
+             Set by modutils >= 2.4.9 and module-init-tools.
+     2 (F): A module was force loaded by insmod -f.
+            Set by modutils >= 2.4.9 and module-init-tools.
+     4 (S): Unsafe SMP processors: SMP with CPUs not designed for SMP.
+     8 (R): A module was forcibly unloaded from the system by rmmod -f.
+    16 (M): A hardware machine check error occurred on the system.
+    32 (B): A bad page was discovered on the system.
+    64 (U): The user has asked that the system be marked "tainted". This
+            could be because they are running software that directly modifies
+            the hardware, or for other reasons.
+   128 (D): The system has died.
+   256 (A): The ACPI DSDT has been overridden with one supplied by the user
+            instead of using the one provided by the hardware.
+   512 (W): A kernel warning has occurred.
+  1024 (C): A module from drivers/staging was loaded.
+  2048 (I): The system is working around a severe firmware bug.
+  4096 (O): An out-of-tree module has been loaded.
+  8192 (E): An unsigned module has been loaded in a kernel supporting module
+            signature.
+ 16384 (L): A soft lockup has previously occurred on the system.
+ 32768 (K): The kernel has been live patched.
+ 65536 (X): Auxiliary taint, defined and used by for distros.
 
 ==============================================================
 

kernel/panic.c

@@ -328,27 +328,12 @@ const struct taint_flag taint_flags[TAINT_FLAGS_COUNT] = {
 };
 
 /**
- *	print_tainted - return a string to represent the kernel taint state.
+ * print_tainted - return a string to represent the kernel taint state.
  *
- *  'P' - Proprietary module has been loaded.
- *  'F' - Module has been forcibly loaded.
- *  'S' - SMP with CPUs not designed for SMP.
- *  'R' - User forced a module unload.
- *  'M' - System experienced a machine check exception.
- *  'B' - System has hit bad_page.
- *  'U' - Userspace-defined naughtiness.
- *  'D' - Kernel has oopsed before
- *  'A' - ACPI table overridden.
- *  'W' - Taint on warning.
- *  'C' - modules from drivers/staging are loaded.
- *  'I' - Working around severe firmware bug.
- *  'O' - Out-of-tree module has been loaded.
- *  'E' - Unsigned module has been loaded.
- *  'L' - A soft lockup has previously occurred.
- *  'K' - Kernel has been live patched.
- *  'X' - Auxiliary taint, for distros' use.
+ * For individual taint flag meanings, see Documentation/sysctl/kernel.txt
  *
- *	The string is overwritten by the next call to print_tainted().
+ * The string is overwritten by the next call to print_tainted(),
+ * but is always NULL terminated.
  */
 const char *print_tainted(void)
 {