kasan: support kasan.stacktrace for SW_TAGS

Add support for the kasan.stacktrace command-line argument for Software
Tag-Based KASAN.

The following patch adds a command-line argument for selecting the stack
ring size, and, as the stack ring is supported by both the Software and
the Hardware Tag-Based KASAN modes, it is natural that both of them have
support for kasan.stacktrace too.

Link: https://lkml.kernel.org/r/3b43059103faa7f8796017847b7d674b658f11b5.1662411799.git.andreyknvl@google.com
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Reviewed-by: Marco Elver <elver@google.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Evgenii Stepanov <eugenis@google.com>
Cc: Peter Collingbourne <pcc@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

1 files changed, 24 insertions, 12 deletions

diff --git a/mm/kasan/kasan.h b/mm/kasan/kasan.h
index cfff81139d67..447baf1a7a2e 100644
--- a/mm/kasan/kasan.h
+++ b/mm/kasan/kasan.h
@@ -8,13 +8,31 @@
 #include <linux/kfence.h>
 #include <linux/stackdepot.h>
 
-#ifdef CONFIG_KASAN_HW_TAGS
+#if defined(CONFIG_KASAN_SW_TAGS) || defined(CONFIG_KASAN_HW_TAGS)
 
 #include <linux/static_key.h>
+
+DECLARE_STATIC_KEY_TRUE(kasan_flag_stacktrace);
+
+static inline bool kasan_stack_collection_enabled(void)
+{
+	return static_branch_unlikely(&kasan_flag_stacktrace);
+}
+
+#else /* CONFIG_KASAN_SW_TAGS || CONFIG_KASAN_HW_TAGS */
+
+static inline bool kasan_stack_collection_enabled(void)
+{
+	return true;
+}
+
+#endif /* CONFIG_KASAN_SW_TAGS || CONFIG_KASAN_HW_TAGS */
+
+#ifdef CONFIG_KASAN_HW_TAGS
+
 #include "../slab.h"
 
 DECLARE_STATIC_KEY_TRUE(kasan_flag_vmalloc);
-DECLARE_STATIC_KEY_TRUE(kasan_flag_stacktrace);
 
 enum kasan_mode {
 	KASAN_MODE_SYNC,
@@ -29,11 +47,6 @@ static inline bool kasan_vmalloc_enabled(void)
 	return static_branch_likely(&kasan_flag_vmalloc);
 }
 
-static inline bool kasan_stack_collection_enabled(void)
-{
-	return static_branch_unlikely(&kasan_flag_stacktrace);
-}
-
 static inline bool kasan_async_fault_possible(void)
 {
 	return kasan_mode == KASAN_MODE_ASYNC || kasan_mode == KASAN_MODE_ASYMM;
@@ -46,11 +59,6 @@ static inline bool kasan_sync_fault_possible(void)
 
 #else /* CONFIG_KASAN_HW_TAGS */
 
-static inline bool kasan_stack_collection_enabled(void)
-{
-	return true;
-}
-
 static inline bool kasan_async_fault_possible(void)
 {
 	return false;
@@ -410,6 +418,10 @@ static inline void kasan_enable_tagging(void) { }
 
 #endif /* CONFIG_KASAN_HW_TAGS */
 
+#if defined(CONFIG_KASAN_SW_TAGS) || defined(CONFIG_KASAN_HW_TAGS)
+void __init kasan_init_tags(void);
+#endif /* CONFIG_KASAN_SW_TAGS || CONFIG_KASAN_HW_TAGS */
+
 #if defined(CONFIG_KASAN_HW_TAGS) && IS_ENABLED(CONFIG_KASAN_KUNIT_TEST)
 
 void kasan_force_async_fault(void);