kasan: rename KASAN_SHADOW_* to KASAN_GRANULE_*

This is a preparatory commit for the upcoming addition of a new hardware
tag-based (MTE-based) KASAN mode.

The new mode won't be using shadow memory, but will still use the concept
of memory granules.  Each memory granule maps to a single metadata entry:
8 bytes per one shadow byte for generic mode, 16 bytes per one shadow byte
for software tag-based mode, and 16 bytes per one allocation tag for
hardware tag-based mode.

Rename KASAN_SHADOW_SCALE_SIZE to KASAN_GRANULE_SIZE, and
KASAN_SHADOW_MASK to KASAN_GRANULE_MASK.

Also use MASK when used as a mask, otherwise use SIZE.

No functional changes.

Link: https://lkml.kernel.org/r/939b5754e47f528a6e6a6f28ffc5815d8d128033.1606161801.git.andreyknvl@google.com
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Signed-off-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
Reviewed-by: Marco Elver <elver@google.com>
Reviewed-by: Alexander Potapenko <glider@google.com>
Tested-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Branislav Rankov <Branislav.Rankov@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Evgenii Stepanov <eugenis@google.com>
Cc: Kevin Brodsky <kevin.brodsky@arm.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Documentation/dev-tools/kasan.rst

@@ -265,7 +265,7 @@ Most mappings in vmalloc space are small, requiring less than a full
 page of shadow space. Allocating a full shadow page per mapping would
 therefore be wasteful. Furthermore, to ensure that different mappings
 use different shadow pages, mappings would have to be aligned to
-``KASAN_SHADOW_SCALE_SIZE * PAGE_SIZE``.
+``KASAN_GRANULE_SIZE * PAGE_SIZE``.
 
 Instead, we share backing space across multiple mappings. We allocate
 a backing page when a mapping in vmalloc space uses a particular page

lib/test_kasan.c

@@ -25,7 +25,7 @@
 
 #include "../mm/kasan/kasan.h"
 
-#define OOB_TAG_OFF (IS_ENABLED(CONFIG_KASAN_GENERIC) ? 0 : KASAN_SHADOW_SCALE_SIZE)
+#define OOB_TAG_OFF (IS_ENABLED(CONFIG_KASAN_GENERIC) ? 0 : KASAN_GRANULE_SIZE)
 
 /*
  * We assign some test results to these globals to make sure the tests

lib/test_kasan_module.c

@@ -15,7 +15,7 @@
 
 #include "../mm/kasan/kasan.h"
 
-#define OOB_TAG_OFF (IS_ENABLED(CONFIG_KASAN_GENERIC) ? 0 : KASAN_SHADOW_SCALE_SIZE)
+#define OOB_TAG_OFF (IS_ENABLED(CONFIG_KASAN_GENERIC) ? 0 : KASAN_GRANULE_SIZE)
 
 static noinline void __init copy_user_test(void)
 {

mm/kasan/common.c

@@ -106,7 +106,7 @@ void *memcpy(void *dest, const void *src, size_t len)
 
 /*
  * Poisons the shadow memory for 'size' bytes starting from 'addr'.
- * Memory addresses should be aligned to KASAN_SHADOW_SCALE_SIZE.
+ * Memory addresses should be aligned to KASAN_GRANULE_SIZE.
  */
 void poison_range(const void *address, size_t size, u8 value)
 {
@@ -138,13 +138,13 @@ void unpoison_range(const void *address, size_t size)
 
 	poison_range(address, size, tag);
 
-	if (size & KASAN_SHADOW_MASK) {
+	if (size & KASAN_GRANULE_MASK) {
 		u8 *shadow = (u8 *)kasan_mem_to_shadow(address + size);
 
 		if (IS_ENABLED(CONFIG_KASAN_SW_TAGS))
 			*shadow = tag;
 		else
-			*shadow = size & KASAN_SHADOW_MASK;
+			*shadow = size & KASAN_GRANULE_MASK;
 	}
 }
 
@@ -301,7 +301,7 @@ void kasan_unpoison_object_data(struct kmem_cache *cache, void *object)
 void kasan_poison_object_data(struct kmem_cache *cache, void *object)
 {
 	poison_range(object,
-			round_up(cache->object_size, KASAN_SHADOW_SCALE_SIZE),
+			round_up(cache->object_size, KASAN_GRANULE_SIZE),
 			KASAN_KMALLOC_REDZONE);
 }
 
@@ -373,7 +373,7 @@ static inline bool shadow_invalid(u8 tag, s8 shadow_byte)
 {
 	if (IS_ENABLED(CONFIG_KASAN_GENERIC))
 		return shadow_byte < 0 ||
-			shadow_byte >= KASAN_SHADOW_SCALE_SIZE;
+			shadow_byte >= KASAN_GRANULE_SIZE;
 
 	/* else CONFIG_KASAN_SW_TAGS: */
 	if ((u8)shadow_byte == KASAN_TAG_INVALID)
@@ -412,7 +412,7 @@ static bool __kasan_slab_free(struct kmem_cache *cache, void *object,
 		return true;
 	}
 
-	rounded_up_size = round_up(cache->object_size, KASAN_SHADOW_SCALE_SIZE);
+	rounded_up_size = round_up(cache->object_size, KASAN_GRANULE_SIZE);
 	poison_range(object, rounded_up_size, KASAN_KMALLOC_FREE);
 
 	if ((IS_ENABLED(CONFIG_KASAN_GENERIC) && !quarantine) ||
@@ -445,9 +445,9 @@ static void *__kasan_kmalloc(struct kmem_cache *cache, const void *object,
 		return NULL;
 
 	redzone_start = round_up((unsigned long)(object + size),
-				KASAN_SHADOW_SCALE_SIZE);
+				KASAN_GRANULE_SIZE);
 	redzone_end = round_up((unsigned long)object + cache->object_size,
-				KASAN_SHADOW_SCALE_SIZE);
+				KASAN_GRANULE_SIZE);
 
 	if (IS_ENABLED(CONFIG_KASAN_SW_TAGS))
 		tag = assign_tag(cache, object, false, keep_tag);
@@ -491,7 +491,7 @@ void * __must_check kasan_kmalloc_large(const void *ptr, size_t size,
 
 	page = virt_to_page(ptr);
 	redzone_start = round_up((unsigned long)(ptr + size),
-				KASAN_SHADOW_SCALE_SIZE);
+				KASAN_GRANULE_SIZE);
 	redzone_end = (unsigned long)ptr + page_size(page);
 
 	unpoison_range(ptr, size);
@@ -589,8 +589,8 @@ static int __meminit kasan_mem_notifier(struct notifier_block *nb,
 	shadow_size = nr_shadow_pages << PAGE_SHIFT;
 	shadow_end = shadow_start + shadow_size;
 
-	if (WARN_ON(mem_data->nr_pages % KASAN_SHADOW_SCALE_SIZE) ||
+	if (WARN_ON(mem_data->nr_pages % KASAN_GRANULE_SIZE) ||
-		WARN_ON(start_kaddr % (KASAN_SHADOW_SCALE_SIZE << PAGE_SHIFT)))
+		WARN_ON(start_kaddr % (KASAN_GRANULE_SIZE << PAGE_SHIFT)))
 		return NOTIFY_BAD;
 
 	switch (action) {
@@ -748,7 +748,7 @@ void kasan_poison_vmalloc(const void *start, unsigned long size)
 	if (!is_vmalloc_or_module_addr(start))
 		return;
 
-	size = round_up(size, KASAN_SHADOW_SCALE_SIZE);
+	size = round_up(size, KASAN_GRANULE_SIZE);
 	poison_range(start, size, KASAN_VMALLOC_INVALID);
 }
 
@@ -861,22 +861,22 @@ void kasan_release_vmalloc(unsigned long start, unsigned long end,
 	unsigned long region_start, region_end;
 	unsigned long size;
 
-	region_start = ALIGN(start, PAGE_SIZE * KASAN_SHADOW_SCALE_SIZE);
+	region_start = ALIGN(start, PAGE_SIZE * KASAN_GRANULE_SIZE);
-	region_end = ALIGN_DOWN(end, PAGE_SIZE * KASAN_SHADOW_SCALE_SIZE);
+	region_end = ALIGN_DOWN(end, PAGE_SIZE * KASAN_GRANULE_SIZE);
 
 	free_region_start = ALIGN(free_region_start,
-				  PAGE_SIZE * KASAN_SHADOW_SCALE_SIZE);
+				  PAGE_SIZE * KASAN_GRANULE_SIZE);
 
 	if (start != region_start &&
 	    free_region_start < region_start)
-		region_start -= PAGE_SIZE * KASAN_SHADOW_SCALE_SIZE;
+		region_start -= PAGE_SIZE * KASAN_GRANULE_SIZE;
 
 	free_region_end = ALIGN_DOWN(free_region_end,
-				     PAGE_SIZE * KASAN_SHADOW_SCALE_SIZE);
+				     PAGE_SIZE * KASAN_GRANULE_SIZE);
 
 	if (end != region_end &&
 	    free_region_end > region_end)
-		region_end += PAGE_SIZE * KASAN_SHADOW_SCALE_SIZE;
+		region_end += PAGE_SIZE * KASAN_GRANULE_SIZE;
 
 	shadow_start = kasan_mem_to_shadow((void *)region_start);
 	shadow_end = kasan_mem_to_shadow((void *)region_end);
@@ -902,7 +902,8 @@ int kasan_module_alloc(void *addr, size_t size)
 	unsigned long shadow_start;
 
 	shadow_start = (unsigned long)kasan_mem_to_shadow(addr);
-	scaled_size = (size + KASAN_SHADOW_MASK) >> KASAN_SHADOW_SCALE_SHIFT;
+	scaled_size = (size + KASAN_GRANULE_SIZE - 1) >>
+				KASAN_SHADOW_SCALE_SHIFT;
 	shadow_size = round_up(scaled_size, PAGE_SIZE);
 
 	if (WARN_ON(!PAGE_ALIGNED(shadow_start)))

mm/kasan/generic.c

@@ -46,7 +46,7 @@ static __always_inline bool memory_is_poisoned_1(unsigned long addr)
 	s8 shadow_value = *(s8 *)kasan_mem_to_shadow((void *)addr);
 
 	if (unlikely(shadow_value)) {
-		s8 last_accessible_byte = addr & KASAN_SHADOW_MASK;
+		s8 last_accessible_byte = addr & KASAN_GRANULE_MASK;
 		return unlikely(last_accessible_byte >= shadow_value);
 	}
 
@@ -62,7 +62,7 @@ static __always_inline bool memory_is_poisoned_2_4_8(unsigned long addr,
 	 * Access crosses 8(shadow size)-byte boundary. Such access maps
 	 * into 2 shadow bytes, so we need to check them both.
 	 */
-	if (unlikely(((addr + size - 1) & KASAN_SHADOW_MASK) < size - 1))
+	if (unlikely(((addr + size - 1) & KASAN_GRANULE_MASK) < size - 1))
 		return *shadow_addr || memory_is_poisoned_1(addr + size - 1);
 
 	return memory_is_poisoned_1(addr + size - 1);
@@ -73,7 +73,7 @@ static __always_inline bool memory_is_poisoned_16(unsigned long addr)
 	u16 *shadow_addr = (u16 *)kasan_mem_to_shadow((void *)addr);
 
 	/* Unaligned 16-bytes access maps into 3 shadow bytes. */
-	if (unlikely(!IS_ALIGNED(addr, KASAN_SHADOW_SCALE_SIZE)))
+	if (unlikely(!IS_ALIGNED(addr, KASAN_GRANULE_SIZE)))
 		return *shadow_addr || memory_is_poisoned_1(addr + 15);
 
 	return *shadow_addr;
@@ -134,7 +134,7 @@ static __always_inline bool memory_is_poisoned_n(unsigned long addr,
 		s8 *last_shadow = (s8 *)kasan_mem_to_shadow((void *)last_byte);
 
 		if (unlikely(ret != (unsigned long)last_shadow ||
-			((long)(last_byte & KASAN_SHADOW_MASK) >= *last_shadow)))
+			((long)(last_byte & KASAN_GRANULE_MASK) >= *last_shadow)))
 			return true;
 	}
 	return false;
@@ -200,7 +200,7 @@ void kasan_cache_shutdown(struct kmem_cache *cache)
 
 static void register_global(struct kasan_global *global)
 {
-	size_t aligned_size = round_up(global->size, KASAN_SHADOW_SCALE_SIZE);
+	size_t aligned_size = round_up(global->size, KASAN_GRANULE_SIZE);
 
 	unpoison_range(global->beg, global->size);
 
@@ -274,10 +274,10 @@ EXPORT_SYMBOL(__asan_handle_no_return);
 /* Emitted by compiler to poison alloca()ed objects. */
 void __asan_alloca_poison(unsigned long addr, size_t size)
 {
-	size_t rounded_up_size = round_up(size, KASAN_SHADOW_SCALE_SIZE);
+	size_t rounded_up_size = round_up(size, KASAN_GRANULE_SIZE);
 	size_t padding_size = round_up(size, KASAN_ALLOCA_REDZONE_SIZE) -
 			rounded_up_size;
-	size_t rounded_down_size = round_down(size, KASAN_SHADOW_SCALE_SIZE);
+	size_t rounded_down_size = round_down(size, KASAN_GRANULE_SIZE);
 
 	const void *left_redzone = (const void *)(addr -
 			KASAN_ALLOCA_REDZONE_SIZE);

mm/kasan/generic_report.c

@@ -34,7 +34,7 @@ void *find_first_bad_addr(void *addr, size_t size)
 	void *p = addr;
 
 	while (p < addr + size && !(*(u8 *)kasan_mem_to_shadow(p)))
-		p += KASAN_SHADOW_SCALE_SIZE;
+		p += KASAN_GRANULE_SIZE;
 	return p;
 }
 
@@ -46,14 +46,14 @@ static const char *get_shadow_bug_type(struct kasan_access_info *info)
 	shadow_addr = (u8 *)kasan_mem_to_shadow(info->first_bad_addr);
 
 	/*
-	 * If shadow byte value is in [0, KASAN_SHADOW_SCALE_SIZE) we can look
+	 * If shadow byte value is in [0, KASAN_GRANULE_SIZE) we can look
 	 * at the next shadow byte to determine the type of the bad access.
 	 */
-	if (*shadow_addr > 0 && *shadow_addr <= KASAN_SHADOW_SCALE_SIZE - 1)
+	if (*shadow_addr > 0 && *shadow_addr <= KASAN_GRANULE_SIZE - 1)
 		shadow_addr++;
 
 	switch (*shadow_addr) {
-	case 0 ... KASAN_SHADOW_SCALE_SIZE - 1:
+	case 0 ... KASAN_GRANULE_SIZE - 1:
 		/*
 		 * In theory it's still possible to see these shadow values
 		 * due to a data race in the kernel code.

mm/kasan/init.c

@@ -442,8 +442,8 @@ void kasan_remove_zero_shadow(void *start, unsigned long size)
 	end = addr + (size >> KASAN_SHADOW_SCALE_SHIFT);
 
 	if (WARN_ON((unsigned long)start %
-			(KASAN_SHADOW_SCALE_SIZE * PAGE_SIZE)) ||
+			(KASAN_GRANULE_SIZE * PAGE_SIZE)) ||
-	    WARN_ON(size % (KASAN_SHADOW_SCALE_SIZE * PAGE_SIZE)))
+	    WARN_ON(size % (KASAN_GRANULE_SIZE * PAGE_SIZE)))
 		return;
 
 	for (; addr < end; addr = next) {
@@ -477,8 +477,8 @@ int kasan_add_zero_shadow(void *start, unsigned long size)
 	shadow_end = shadow_start + (size >> KASAN_SHADOW_SCALE_SHIFT);
 
 	if (WARN_ON((unsigned long)start %
-			(KASAN_SHADOW_SCALE_SIZE * PAGE_SIZE)) ||
+			(KASAN_GRANULE_SIZE * PAGE_SIZE)) ||
-	    WARN_ON(size % (KASAN_SHADOW_SCALE_SIZE * PAGE_SIZE)))
+	    WARN_ON(size % (KASAN_GRANULE_SIZE * PAGE_SIZE)))
 		return -EINVAL;
 
 	ret = kasan_populate_early_shadow(shadow_start, shadow_end);

mm/kasan/kasan.h

@@ -5,8 +5,8 @@
 #include <linux/kasan.h>
 #include <linux/stackdepot.h>
 
-#define KASAN_SHADOW_SCALE_SIZE (1UL << KASAN_SHADOW_SCALE_SHIFT)
+#define KASAN_GRANULE_SIZE	(1UL << KASAN_SHADOW_SCALE_SHIFT)
-#define KASAN_SHADOW_MASK       (KASAN_SHADOW_SCALE_SIZE - 1)
+#define KASAN_GRANULE_MASK	(KASAN_GRANULE_SIZE - 1)
 
 #define KASAN_TAG_KERNEL	0xFF /* native kernel pointers tag */
 #define KASAN_TAG_INVALID	0xFE /* inaccessible memory tag */

mm/kasan/report.c

@@ -314,24 +314,24 @@ static bool __must_check get_address_stack_frame_info(const void *addr,
 		return false;
 
 	aligned_addr = round_down((unsigned long)addr, sizeof(long));
-	mem_ptr = round_down(aligned_addr, KASAN_SHADOW_SCALE_SIZE);
+	mem_ptr = round_down(aligned_addr, KASAN_GRANULE_SIZE);
 	shadow_ptr = kasan_mem_to_shadow((void *)aligned_addr);
 	shadow_bottom = kasan_mem_to_shadow(end_of_stack(current));
 
 	while (shadow_ptr >= shadow_bottom && *shadow_ptr != KASAN_STACK_LEFT) {
 		shadow_ptr--;
-		mem_ptr -= KASAN_SHADOW_SCALE_SIZE;
+		mem_ptr -= KASAN_GRANULE_SIZE;
 	}
 
 	while (shadow_ptr >= shadow_bottom && *shadow_ptr == KASAN_STACK_LEFT) {
 		shadow_ptr--;
-		mem_ptr -= KASAN_SHADOW_SCALE_SIZE;
+		mem_ptr -= KASAN_GRANULE_SIZE;
 	}
 
 	if (shadow_ptr < shadow_bottom)
 		return false;
 
-	frame = (const unsigned long *)(mem_ptr + KASAN_SHADOW_SCALE_SIZE);
+	frame = (const unsigned long *)(mem_ptr + KASAN_GRANULE_SIZE);
 	if (frame[0] != KASAN_CURRENT_STACK_FRAME_MAGIC) {
 		pr_err("KASAN internal error: frame info validation failed; invalid marker: %lu\n",
 		       frame[0]);
@@ -599,6 +599,6 @@ void kasan_non_canonical_hook(unsigned long addr)
 	else
 		bug_type = "maybe wild-memory-access";
 	pr_alert("KASAN: %s in range [0x%016lx-0x%016lx]\n", bug_type,
-		 orig_addr, orig_addr + KASAN_SHADOW_MASK);
+		 orig_addr, orig_addr + KASAN_GRANULE_SIZE - 1);
 }
 #endif

mm/kasan/tags_report.c

@@ -76,7 +76,7 @@ void *find_first_bad_addr(void *addr, size_t size)
 	void *end = p + size;
 
 	while (p < end && tag == *(u8 *)kasan_mem_to_shadow(p))
-		p += KASAN_SHADOW_SCALE_SIZE;
+		p += KASAN_GRANULE_SIZE;
 	return p;
 }