taint: convert to indexed initialization

This converts to using indexed initializers instead of comments, adds a
comment on why the taint flags can't be an enum, and make sure that no
one forgets to update the taint_flags when adding new bits.

Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Kees Cook <[email protected]>
Reviewed-by: Andrew Morton <[email protected]>
Cc: Al Viro <[email protected]>
Cc: Alexey Dobriyan <[email protected]>
Cc: Jonathan Corbet <[email protected]>
Cc: Randy Dunlap <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

Author: kees

include/linux/kernel.h

@@ -544,6 +544,7 @@ extern enum system_states {
 	SYSTEM_RESTART,
 } system_state;
 
+/* This cannot be an enum because some may be used in assembly source. */
 #define TAINT_PROPRIETARY_MODULE	0
 #define TAINT_FORCED_MODULE		1
 #define TAINT_CPU_OUT_OF_SPEC		2

kernel/panic.c

@@ -308,23 +308,23 @@ EXPORT_SYMBOL(panic);
  * is being removed anyway.
  */
 const struct taint_flag taint_flags[TAINT_FLAGS_COUNT] = {
-	{ 'P', 'G', true },	/* TAINT_PROPRIETARY_MODULE */
-	{ 'F', ' ', true },	/* TAINT_FORCED_MODULE */
-	{ 'S', ' ', false },	/* TAINT_CPU_OUT_OF_SPEC */
-	{ 'R', ' ', false },	/* TAINT_FORCED_RMMOD */
-	{ 'M', ' ', false },	/* TAINT_MACHINE_CHECK */
-	{ 'B', ' ', false },	/* TAINT_BAD_PAGE */
-	{ 'U', ' ', false },	/* TAINT_USER */
-	{ 'D', ' ', false },	/* TAINT_DIE */
-	{ 'A', ' ', false },	/* TAINT_OVERRIDDEN_ACPI_TABLE */
-	{ 'W', ' ', false },	/* TAINT_WARN */
-	{ 'C', ' ', true },	/* TAINT_CRAP */
-	{ 'I', ' ', false },	/* TAINT_FIRMWARE_WORKAROUND */
-	{ 'O', ' ', true },	/* TAINT_OOT_MODULE */
-	{ 'E', ' ', true },	/* TAINT_UNSIGNED_MODULE */
-	{ 'L', ' ', false },	/* TAINT_SOFTLOCKUP */
-	{ 'K', ' ', true },	/* TAINT_LIVEPATCH */
-	{ 'X', ' ', true },	/* TAINT_AUX */
+	[ TAINT_PROPRIETARY_MODULE ]	= { 'P', 'G', true },
+	[ TAINT_FORCED_MODULE ]		= { 'F', ' ', true },
+	[ TAINT_CPU_OUT_OF_SPEC ]	= { 'S', ' ', false },
+	[ TAINT_FORCED_RMMOD ]		= { 'R', ' ', false },
+	[ TAINT_MACHINE_CHECK ]		= { 'M', ' ', false },
+	[ TAINT_BAD_PAGE ]		= { 'B', ' ', false },
+	[ TAINT_USER ]			= { 'U', ' ', false },
+	[ TAINT_DIE ]			= { 'D', ' ', false },
+	[ TAINT_OVERRIDDEN_ACPI_TABLE ]	= { 'A', ' ', false },
+	[ TAINT_WARN ]			= { 'W', ' ', false },
+	[ TAINT_CRAP ]			= { 'C', ' ', true },
+	[ TAINT_FIRMWARE_WORKAROUND ]	= { 'I', ' ', false },
+	[ TAINT_OOT_MODULE ]		= { 'O', ' ', true },
+	[ TAINT_UNSIGNED_MODULE ]	= { 'E', ' ', true },
+	[ TAINT_SOFTLOCKUP ]		= { 'L', ' ', false },
+	[ TAINT_LIVEPATCH ]		= { 'K', ' ', true },
+	[ TAINT_AUX ]			= { 'X', ' ', true },
 };
 
 /**
@@ -354,6 +354,8 @@ const char *print_tainted(void)
 {
 	static char buf[TAINT_FLAGS_COUNT + sizeof("Tainted: ")];
 
+	BUILD_BUG_ON(ARRAY_SIZE(taint_flags) != TAINT_FLAGS_COUNT);
+
 	if (tainted_mask) {
 		char *s;
 		int i;