kasan: clean up metadata byte definitions

Most of the metadata byte values are only used for Generic KASAN.

Remove KASAN_KMALLOC_FREETRACK definition for !CONFIG_KASAN_GENERIC case,
and put it along with other metadata values for the Generic mode under a
corresponding ifdef.

Link: https://lkml.kernel.org/r/ac11d6e9e007c95e472e8fdd22efb6074ef3c6d8.1643047180.git.andreyknvl@google.com
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Reviewed-by: Alexander Potapenko <glider@google.com>
Acked-by: Marco Elver <elver@google.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Evgenii Stepanov <eugenis@google.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Peter Collingbourne <pcc@google.com>
Cc: Vincenzo Frascino <vincenzo.frascino@arm.com>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>

mm/kasan/kasan.h

@@ -71,15 +71,16 @@ static inline bool kasan_sync_fault_possible(void)
 #define KASAN_PAGE_REDZONE      0xFE  /* redzone for kmalloc_large allocations */
 #define KASAN_KMALLOC_REDZONE   0xFC  /* redzone inside slub object */
 #define KASAN_KMALLOC_FREE      0xFB  /* object was freed (kmem_cache_free/kfree) */
-#define KASAN_KMALLOC_FREETRACK 0xFA  /* object was freed and has free track set */
 #else
 #define KASAN_FREE_PAGE         KASAN_TAG_INVALID
 #define KASAN_PAGE_REDZONE      KASAN_TAG_INVALID
 #define KASAN_KMALLOC_REDZONE   KASAN_TAG_INVALID
 #define KASAN_KMALLOC_FREE      KASAN_TAG_INVALID
-#define KASAN_KMALLOC_FREETRACK KASAN_TAG_INVALID
 #endif
 
+#ifdef CONFIG_KASAN_GENERIC
+
+#define KASAN_KMALLOC_FREETRACK 0xFA  /* object was freed and has free track set */
 #define KASAN_GLOBAL_REDZONE    0xF9  /* redzone for global variable */
 #define KASAN_VMALLOC_INVALID   0xF8  /* unallocated space in vmapped page */
 
@@ -110,6 +111,8 @@ static inline bool kasan_sync_fault_possible(void)
 #define KASAN_ABI_VERSION 1
 #endif
 
+#endif /* CONFIG_KASAN_GENERIC */
+
 /* Metadata layout customization. */
 #define META_BYTES_PER_BLOCK 1
 #define META_BLOCKS_PER_ROW 16