taint/module: Clean up global and module taint flags handling

The commit 66cc69e34e86a231 ("Fix: module signature vs tracepoints:
add new TAINT_UNSIGNED_MODULE") updated module_taint_flags() to
potentially print one more character. But it did not increase the
size of the corresponding buffers in m_show() and print_modules().

We have recently done the same mistake when adding a taint flag
for livepatching, see
https://lkml.kernel.org/r/cfba2c823bb984690b73572aaae1db596b54a082.1472137475.git.jpoimboe@redhat.com

Also struct module uses an incompatible type for mod-taints flags.
It survived from the commit 2bc2d61a9638dab670d ("[PATCH] list module
taint flags in Oops/panic"). There was used "int" for the global taint
flags at these times. But only the global tain flags was later changed
to "unsigned long" by the commit 25ddbb18aae33ad2 ("Make the taint
flags reliable").

This patch defines TAINT_FLAGS_COUNT that can be used to create
arrays and buffers of the right size. Note that we could not use
enum because the taint flag indexes are used also in assembly code.

Then it reworks the table that describes the taint flags. The TAINT_*
numbers can be used as the index. Instead, we add information
if the taint flag is also shown per-module.

Finally, it uses "unsigned long", bit operations, and the updated
taint_flags table also for mod->taints.

It is not optimal because only few taint flags can be printed by
module_taint_flags(). But better be on the safe side. IMHO, it is
not worth the optimization and this is a good compromise.

Signed-off-by: Petr Mladek <pmladek@suse.com>
Link: http://lkml.kernel.org/r/1474458442-21581-1-git-send-email-pmladek@suse.com
[jeyu@redhat.com: fix broken lkml link in changelog]
Signed-off-by: Jessica Yu <jeyu@redhat.com>

1 files changed, 25 insertions, 28 deletions

diff --git a/kernel/panic.c b/kernel/panic.c
index e6480e20379e..c51edaa04fce 100644
--- a/kernel/panic.c
+++ b/kernel/panic.c
@@ -298,30 +298,27 @@ void panic(const char *fmt, ...)
 
 EXPORT_SYMBOL(panic);
 
-
-struct tnt {
-	u8	bit;
-	char	true;
-	char	false;
-};
-
-static const struct tnt tnts[] = {
-	{ TAINT_PROPRIETARY_MODULE,	'P', 'G' },
-	{ TAINT_FORCED_MODULE,		'F', ' ' },
-	{ TAINT_CPU_OUT_OF_SPEC,	'S', ' ' },
-	{ TAINT_FORCED_RMMOD,		'R', ' ' },
-	{ TAINT_MACHINE_CHECK,		'M', ' ' },
-	{ TAINT_BAD_PAGE,		'B', ' ' },
-	{ TAINT_USER,			'U', ' ' },
-	{ TAINT_DIE,			'D', ' ' },
-	{ TAINT_OVERRIDDEN_ACPI_TABLE,	'A', ' ' },
-	{ TAINT_WARN,			'W', ' ' },
-	{ TAINT_CRAP,			'C', ' ' },
-	{ TAINT_FIRMWARE_WORKAROUND,	'I', ' ' },
-	{ TAINT_OOT_MODULE,		'O', ' ' },
-	{ TAINT_UNSIGNED_MODULE,	'E', ' ' },
-	{ TAINT_SOFTLOCKUP,		'L', ' ' },
-	{ TAINT_LIVEPATCH,		'K', ' ' },
+/*
+ * TAINT_FORCED_RMMOD could be a per-module flag but the module
+ * 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 */
 };
 
 /**
@@ -348,16 +345,16 @@ static const struct tnt tnts[] = {
  */
 const char *print_tainted(void)
 {
-	static char buf[ARRAY_SIZE(tnts) + sizeof("Tainted: ")];
+	static char buf[TAINT_FLAGS_COUNT + sizeof("Tainted: ")];
 
 	if (tainted_mask) {
 		char *s;
 		int i;
 
 		s = buf + sprintf(buf, "Tainted: ");
-		for (i = 0; i < ARRAY_SIZE(tnts); i++) {
-			const struct tnt *t = &tnts[i];
-			*s++ = test_bit(t->bit, &tainted_mask) ?
+		for (i = 0; i < TAINT_FLAGS_COUNT; i++) {
+			const struct taint_flag *t = &taint_flags[i];
+			*s++ = test_bit(i, &tainted_mask) ?
 					t->true : t->false;
 		}
 		*s = 0;