[PATCH v4 35/39] kasan, arm64: implement HW_TAGS runtime

[Andrey Konovalov <andreyknvl@google.com>]

Provide implementation of KASAN functions required for the hardware
tag-based mode. Those include core functions for memory and pointer
tagging (tags_hw.c) and bug reporting (report_tags_hw.c). Also adapt
common KASAN code to support the new mode.

Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Signed-off-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Reviewed-by: Marco Elver <elver@google.com>
---
Change-Id: I8a8689ba098174a4d0ef3f1d008178387c80ee1c
---
 arch/arm64/include/asm/memory.h   |  4 +-
 arch/arm64/kernel/setup.c         |  5 ++-
 include/linux/kasan.h             |  6 +--
 include/linux/mm.h                |  2 +-
 include/linux/page-flags-layout.h |  2 +-
 mm/kasan/Makefile                 |  5 +++
 mm/kasan/common.c                 | 15 ++++---
 mm/kasan/hw_tags.c                | 70 +++++++++++++++++++++++++++++++
 mm/kasan/kasan.h                  | 17 ++++++--
 mm/kasan/report_hw_tags.c         | 42 +++++++++++++++++++
 mm/kasan/report_sw_tags.c         |  2 +-
 mm/kasan/shadow.c                 |  2 +-
 mm/kasan/sw_tags.c                |  2 +-
 13 files changed, 152 insertions(+), 22 deletions(-)
 create mode 100644 mm/kasan/hw_tags.c
 create mode 100644 mm/kasan/report_hw_tags.c

diff --git a/arch/arm64/include/asm/memory.h b/arch/arm64/include/asm/memory.h
index de9af7bea90d..b5d6b824c21c 100644
--- a/arch/arm64/include/asm/memory.h
+++ b/arch/arm64/include/asm/memory.h
@@ -215,7 +215,7 @@ static inline unsigned long kaslr_offset(void)
 	(__force __typeof__(addr))__addr;				\
 })
 
-#ifdef CONFIG_KASAN_SW_TAGS
+#if defined(CONFIG_KASAN_SW_TAGS) || defined(CONFIG_KASAN_HW_TAGS)
 #define __tag_shifted(tag)	((u64)(tag) << 56)
 #define __tag_reset(addr)	__untagged_addr(addr)
 #define __tag_get(addr)		(__u8)((u64)(addr) >> 56)
@@ -223,7 +223,7 @@ static inline unsigned long kaslr_offset(void)
 #define __tag_shifted(tag)	0UL
 #define __tag_reset(addr)	(addr)
 #define __tag_get(addr)		0
-#endif /* CONFIG_KASAN_SW_TAGS */
+#endif /* CONFIG_KASAN_SW_TAGS || CONFIG_KASAN_HW_TAGS */
 
 static inline const void *__tag_set(const void *addr, u8 tag)
 {
diff --git a/arch/arm64/kernel/setup.c b/arch/arm64/kernel/setup.c
index 77c4c9bad1b8..b07d9fbfa8b6 100644
--- a/arch/arm64/kernel/setup.c
+++ b/arch/arm64/kernel/setup.c
@@ -358,7 +358,10 @@ void __init __no_sanitize_address setup_arch(char **cmdline_p)
 	smp_init_cpus();
 	smp_build_mpidr_hash();
 
-	/* Init percpu seeds for random tags after cpus are set up. */
+	/*
+	 * For CONFIG_KASAN_SW_TAGS this initializes percpu seeds and must
+	 * come after cpus are set up.
+	 */
 	kasan_init_tags();
 
 #ifdef CONFIG_ARM64_SW_TTBR0_PAN
diff --git a/include/linux/kasan.h b/include/linux/kasan.h
index 894eddf42168..3f3f541e5d5f 100644
--- a/include/linux/kasan.h
+++ b/include/linux/kasan.h
@@ -181,7 +181,7 @@ static inline void kasan_record_aux_stack(void *ptr) {}
 
 #endif /* CONFIG_KASAN_GENERIC */
 
-#ifdef CONFIG_KASAN_SW_TAGS
+#if defined(CONFIG_KASAN_SW_TAGS) || defined(CONFIG_KASAN_HW_TAGS)
 
 void kasan_init_tags(void);
 
@@ -190,7 +190,7 @@ void *kasan_reset_tag(const void *addr);
 bool kasan_report(unsigned long addr, size_t size,
 		bool is_write, unsigned long ip);
 
-#else /* CONFIG_KASAN_SW_TAGS */
+#else /* CONFIG_KASAN_SW_TAGS || CONFIG_KASAN_HW_TAGS */
 
 static inline void kasan_init_tags(void) { }
 
@@ -199,7 +199,7 @@ static inline void *kasan_reset_tag(const void *addr)
 	return (void *)addr;
 }
 
-#endif /* CONFIG_KASAN_SW_TAGS */
+#endif /* CONFIG_KASAN_SW_TAGS || CONFIG_KASAN_HW_TAGS*/
 
 #ifdef CONFIG_KASAN_VMALLOC
 
diff --git a/include/linux/mm.h b/include/linux/mm.h
index 4312c6c808e9..a3cac68c737c 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -1411,7 +1411,7 @@ static inline bool cpupid_match_pid(struct task_struct *task, int cpupid)
 }
 #endif /* CONFIG_NUMA_BALANCING */
 
-#ifdef CONFIG_KASAN_SW_TAGS
+#if defined(CONFIG_KASAN_SW_TAGS) || defined(CONFIG_KASAN_HW_TAGS)
 static inline u8 page_kasan_tag(const struct page *page)
 {
 	return (page->flags >> KASAN_TAG_PGSHIFT) & KASAN_TAG_MASK;
diff --git a/include/linux/page-flags-layout.h b/include/linux/page-flags-layout.h
index e200eef6a7fd..7d4ec26d8a3e 100644
--- a/include/linux/page-flags-layout.h
+++ b/include/linux/page-flags-layout.h
@@ -77,7 +77,7 @@
 #define LAST_CPUPID_SHIFT 0
 #endif
 
-#ifdef CONFIG_KASAN_SW_TAGS
+#if defined(CONFIG_KASAN_SW_TAGS) || defined(CONFIG_KASAN_HW_TAGS)
 #define KASAN_TAG_WIDTH 8
 #else
 #define KASAN_TAG_WIDTH 0
diff --git a/mm/kasan/Makefile b/mm/kasan/Makefile
index f1d68a34f3c9..9fe39a66388a 100644
--- a/mm/kasan/Makefile
+++ b/mm/kasan/Makefile
@@ -10,8 +10,10 @@ CFLAGS_REMOVE_init.o = $(CC_FLAGS_FTRACE)
 CFLAGS_REMOVE_quarantine.o = $(CC_FLAGS_FTRACE)
 CFLAGS_REMOVE_report.o = $(CC_FLAGS_FTRACE)
 CFLAGS_REMOVE_report_generic.o = $(CC_FLAGS_FTRACE)
+CFLAGS_REMOVE_report_hw_tags.o = $(CC_FLAGS_FTRACE)
 CFLAGS_REMOVE_report_sw_tags.o = $(CC_FLAGS_FTRACE)
 CFLAGS_REMOVE_shadow.o = $(CC_FLAGS_FTRACE)
+CFLAGS_REMOVE_hw_tags.o = $(CC_FLAGS_FTRACE)
 CFLAGS_REMOVE_sw_tags.o = $(CC_FLAGS_FTRACE)
 
 # Function splitter causes unnecessary splits in __asan_load1/__asan_store1
@@ -27,10 +29,13 @@ CFLAGS_init.o := $(CC_FLAGS_KASAN_RUNTIME)
 CFLAGS_quarantine.o := $(CC_FLAGS_KASAN_RUNTIME)
 CFLAGS_report.o := $(CC_FLAGS_KASAN_RUNTIME)
 CFLAGS_report_generic.o := $(CC_FLAGS_KASAN_RUNTIME)
+CFLAGS_report_hw_tags.o := $(CC_FLAGS_KASAN_RUNTIME)
 CFLAGS_report_sw_tags.o := $(CC_FLAGS_KASAN_RUNTIME)
 CFLAGS_shadow.o := $(CC_FLAGS_KASAN_RUNTIME)
+CFLAGS_hw_tags.o := $(CC_FLAGS_KASAN_RUNTIME)
 CFLAGS_sw_tags.o := $(CC_FLAGS_KASAN_RUNTIME)
 
 obj-$(CONFIG_KASAN) := common.o report.o
 obj-$(CONFIG_KASAN_GENERIC) += init.o generic.o report_generic.o shadow.o quarantine.o
+obj-$(CONFIG_KASAN_HW_TAGS) += hw_tags.o report_hw_tags.o
 obj-$(CONFIG_KASAN_SW_TAGS) += init.o report_sw_tags.o shadow.o sw_tags.o
diff --git a/mm/kasan/common.c b/mm/kasan/common.c
index d0b3ff410b0c..2bb0ef6da6bd 100644
--- a/mm/kasan/common.c
+++ b/mm/kasan/common.c
@@ -113,7 +113,7 @@ void kasan_free_pages(struct page *page, unsigned int order)
  */
 static inline unsigned int optimal_redzone(unsigned int object_size)
 {
-	if (IS_ENABLED(CONFIG_KASAN_SW_TAGS))
+	if (!IS_ENABLED(CONFIG_KASAN_GENERIC))
 		return 0;
 
 	return
@@ -178,14 +178,14 @@ size_t kasan_metadata_size(struct kmem_cache *cache)
 struct kasan_alloc_meta *get_alloc_info(struct kmem_cache *cache,
 					const void *object)
 {
-	return (void *)object + cache->kasan_info.alloc_meta_offset;
+	return (void *)reset_tag(object) + cache->kasan_info.alloc_meta_offset;
 }
 
 struct kasan_free_meta *get_free_info(struct kmem_cache *cache,
 				      const void *object)
 {
 	BUILD_BUG_ON(sizeof(struct kasan_free_meta) > 32);
-	return (void *)object + cache->kasan_info.free_meta_offset;
+	return (void *)reset_tag(object) + cache->kasan_info.free_meta_offset;
 }
 
 void kasan_poison_slab(struct page *page)
@@ -267,9 +267,8 @@ void * __must_check kasan_init_slab_obj(struct kmem_cache *cache,
 	alloc_info = get_alloc_info(cache, object);
 	__memset(alloc_info, 0, sizeof(*alloc_info));
 
-	if (IS_ENABLED(CONFIG_KASAN_SW_TAGS))
-		object = set_tag(object,
-				assign_tag(cache, object, true, false));
+	if (IS_ENABLED(CONFIG_KASAN_SW_TAGS) || IS_ENABLED(CONFIG_KASAN_HW_TAGS))
+		object = set_tag(object, assign_tag(cache, object, true, false));
 
 	return (void *)object;
 }
@@ -337,10 +336,10 @@ static void *__kasan_kmalloc(struct kmem_cache *cache, const void *object,
 	redzone_end = round_up((unsigned long)object + cache->object_size,
 				KASAN_GRANULE_SIZE);
 
-	if (IS_ENABLED(CONFIG_KASAN_SW_TAGS))
+	if (IS_ENABLED(CONFIG_KASAN_SW_TAGS) || IS_ENABLED(CONFIG_KASAN_HW_TAGS))
 		tag = assign_tag(cache, object, false, keep_tag);
 
-	/* Tag is ignored in set_tag without CONFIG_KASAN_SW_TAGS */
+	/* Tag is ignored in set_tag without CONFIG_KASAN_SW/HW_TAGS */
 	kasan_unpoison_memory(set_tag(object, tag), size);
 	kasan_poison_memory((void *)redzone_start, redzone_end - redzone_start,
 		KASAN_KMALLOC_REDZONE);
diff --git a/mm/kasan/hw_tags.c b/mm/kasan/hw_tags.c
new file mode 100644
index 000000000000..7f0568df2a93
--- /dev/null
+++ b/mm/kasan/hw_tags.c
@@ -0,0 +1,70 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * This file contains core hardware tag-based KASAN code.
+ *
+ * Copyright (c) 2020 Google, Inc.
+ * Author: Andrey Konovalov <andreyknvl@google.com>
+ */
+
+#include <linux/kasan.h>
+#include <linux/kernel.h>
+#include <linux/memory.h>
+#include <linux/mm.h>
+#include <linux/string.h>
+#include <linux/types.h>
+
+#include "kasan.h"
+
+void kasan_init_tags(void)
+{
+	init_tags(KASAN_TAG_MAX);
+}
+
+void *kasan_reset_tag(const void *addr)
+{
+	return reset_tag(addr);
+}
+
+void kasan_poison_memory(const void *address, size_t size, u8 value)
+{
+	set_mem_tag_range(reset_tag(address),
+			  round_up(size, KASAN_GRANULE_SIZE), value);
+}
+
+void kasan_unpoison_memory(const void *address, size_t size)
+{
+	set_mem_tag_range(reset_tag(address),
+			  round_up(size, KASAN_GRANULE_SIZE), get_tag(address));
+}
+
+u8 random_tag(void)
+{
+	return get_random_tag();
+}
+
+bool check_invalid_free(void *addr)
+{
+	u8 ptr_tag = get_tag(addr);
+	u8 mem_tag = get_mem_tag(addr);
+
+	return (mem_tag == KASAN_TAG_INVALID) ||
+		(ptr_tag != KASAN_TAG_KERNEL && ptr_tag != mem_tag);
+}
+
+void kasan_set_free_info(struct kmem_cache *cache,
+				void *object, u8 tag)
+{
+	struct kasan_alloc_meta *alloc_meta;
+
+	alloc_meta = get_alloc_info(cache, object);
+	kasan_set_track(&alloc_meta->free_track[0], GFP_NOWAIT);
+}
+
+struct kasan_track *kasan_get_free_track(struct kmem_cache *cache,
+				void *object, u8 tag)
+{
+	struct kasan_alloc_meta *alloc_meta;
+
+	alloc_meta = get_alloc_info(cache, object);
+	return &alloc_meta->free_track[0];
+}
diff --git a/mm/kasan/kasan.h b/mm/kasan/kasan.h
index cf03640c8874..f6363d1d6d26 100644
--- a/mm/kasan/kasan.h
+++ b/mm/kasan/kasan.h
@@ -153,6 +153,10 @@ struct kasan_alloc_meta *get_alloc_info(struct kmem_cache *cache,
 struct kasan_free_meta *get_free_info(struct kmem_cache *cache,
 					const void *object);
 
+void kasan_poison_memory(const void *address, size_t size, u8 value);
+
+#if defined(CONFIG_KASAN_GENERIC) || defined(CONFIG_KASAN_SW_TAGS)
+
 static inline const void *kasan_shadow_to_mem(const void *shadow_addr)
 {
 	return (void *)(((unsigned long)shadow_addr - KASAN_SHADOW_OFFSET)
@@ -164,8 +168,6 @@ static inline bool addr_has_metadata(const void *addr)
 	return (addr >= kasan_shadow_to_mem((void *)KASAN_SHADOW_START));
 }
 
-void kasan_poison_memory(const void *address, size_t size, u8 value);
-
 /**
  * check_memory_region - Check memory region, and report if invalid access.
  * @addr: the accessed address
@@ -177,6 +179,15 @@ void kasan_poison_memory(const void *address, size_t size, u8 value);
 bool check_memory_region(unsigned long addr, size_t size, bool write,
 				unsigned long ret_ip);
 
+#else /* CONFIG_KASAN_GENERIC || CONFIG_KASAN_SW_TAGS */
+
+static inline bool addr_has_metadata(const void *addr)
+{
+	return true;
+}
+
+#endif /* CONFIG_KASAN_GENERIC || CONFIG_KASAN_SW_TAGS */
+
 bool check_invalid_free(void *addr);
 
 void *find_first_bad_addr(void *addr, size_t size);
@@ -213,7 +224,7 @@ static inline void quarantine_reduce(void) { }
 static inline void quarantine_remove_cache(struct kmem_cache *cache) { }
 #endif
 
-#ifdef CONFIG_KASAN_SW_TAGS
+#if defined(CONFIG_KASAN_SW_TAGS) || defined(CONFIG_KASAN_HW_TAGS)
 
 void print_tags(u8 addr_tag, const void *addr);
 
diff --git a/mm/kasan/report_hw_tags.c b/mm/kasan/report_hw_tags.c
new file mode 100644
index 000000000000..d8423d1e3b6b
--- /dev/null
+++ b/mm/kasan/report_hw_tags.c
@@ -0,0 +1,42 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * This file contains hardware tag-based KASAN specific error reporting code.
+ *
+ * Copyright (c) 2020 Google, Inc.
+ * Author: Andrey Konovalov <andreyknvl@google.com>
+ */
+
+#include <linux/kasan.h>
+#include <linux/kernel.h>
+#include <linux/memory.h>
+#include <linux/mm.h>
+#include <linux/string.h>
+#include <linux/types.h>
+
+#include "kasan.h"
+
+const char *get_bug_type(struct kasan_access_info *info)
+{
+	return "invalid-access";
+}
+
+void *find_first_bad_addr(void *addr, size_t size)
+{
+	return reset_tag(addr);
+}
+
+void metadata_fetch_row(char *buffer, void *row)
+{
+	int i;
+
+	for (i = 0; i < META_BYTES_PER_ROW; i++)
+		buffer[i] = mte_get_mem_tag(row + i * KASAN_GRANULE_SIZE);
+}
+
+void print_tags(u8 addr_tag, const void *addr)
+{
+	u8 memory_tag = mte_get_mem_tag((void *)addr);
+
+	pr_err("Pointer tag: [%02x], memory tag: [%02x]\n",
+		addr_tag, memory_tag);
+}
diff --git a/mm/kasan/report_sw_tags.c b/mm/kasan/report_sw_tags.c
index add2dfe6169c..aebc44a29e83 100644
--- a/mm/kasan/report_sw_tags.c
+++ b/mm/kasan/report_sw_tags.c
@@ -1,6 +1,6 @@
 // SPDX-License-Identifier: GPL-2.0
 /*
- * This file contains tag-based KASAN specific error reporting code.
+ * This file contains software tag-based KASAN specific error reporting code.
  *
  * Copyright (c) 2014 Samsung Electronics Co., Ltd.
  * Author: Andrey Ryabinin <ryabinin.a.a@gmail.com>
diff --git a/mm/kasan/shadow.c b/mm/kasan/shadow.c
index 1fadd4930d54..616ac64c4a21 100644
--- a/mm/kasan/shadow.c
+++ b/mm/kasan/shadow.c
@@ -107,7 +107,7 @@ void kasan_unpoison_memory(const void *address, size_t size)
 
 		if (IS_ENABLED(CONFIG_KASAN_SW_TAGS))
 			*shadow = tag;
-		else
+		else /* CONFIG_KASAN_GENERIC */
 			*shadow = size & KASAN_GRANULE_MASK;
 	}
 }
diff --git a/mm/kasan/sw_tags.c b/mm/kasan/sw_tags.c
index b2638c2cd58a..ccc35a311179 100644
--- a/mm/kasan/sw_tags.c
+++ b/mm/kasan/sw_tags.c
@@ -1,6 +1,6 @@
 // SPDX-License-Identifier: GPL-2.0
 /*
- * This file contains core tag-based KASAN code.
+ * This file contains core software tag-based KASAN code.
  *
  * Copyright (c) 2018 Google, Inc.
  * Author: Andrey Konovalov <andreyknvl@google.com>
-- 
2.28.0.709.gb0816b6eb0-goog