This patch add a set of arch_*() memory tagging helpers currently only
defined for arm64 when hardware tag-based KASAN is enabled. These helpers
will be used by KASAN runtime to implement the hardware tag-based mode.

The arch-level indirection level is introduced to simplify adding hardware
tag-based KASAN support for other architectures in the future by defining
the appropriate arch_*() macros.

Signed-off-by: Andrey Konovalov <[email protected]>
Co-developed-by: Vincenzo Frascino <[email protected]>
Signed-off-by: Vincenzo Frascino <[email protected]>
Reviewed-by: Catalin Marinas <[email protected]>
---
Change-Id: I42b0795a28067872f8308e00c6f0195bca435c2a
---
 arch/arm64/include/asm/memory.h |  9 +++++++++
 mm/kasan/kasan.h                | 26 ++++++++++++++++++++++++++
 2 files changed, 35 insertions(+)

diff --git a/arch/arm64/include/asm/memory.h b/arch/arm64/include/asm/memory.h
index cd61239bae8c..419bbace29d5 100644
--- a/arch/arm64/include/asm/memory.h
+++ b/arch/arm64/include/asm/memory.h
@@ -230,6 +230,15 @@ static inline const void *__tag_set(const void *addr, u8 
tag)
        return (const void *)(__addr | __tag_shifted(tag));
 }
 
+#ifdef CONFIG_KASAN_HW_TAGS
+#define arch_enable_tagging()                  mte_enable()
+#define arch_init_tags(max_tag)                        mte_init_tags(max_tag)
+#define arch_get_random_tag()                  mte_get_random_tag()
+#define arch_get_mem_tag(addr)                 mte_get_mem_tag(addr)
+#define arch_set_mem_tag_range(addr, size, tag)        \
+                       mte_set_mem_tag_range((addr), (size), (tag))
+#endif /* CONFIG_KASAN_HW_TAGS */
+
 /*
  * Physical vs virtual RAM address space conversion.  These are
  * private definitions which should NOT be used outside memory.h
diff --git a/mm/kasan/kasan.h b/mm/kasan/kasan.h
index b5b00bff358f..ae7def3b725b 100644
--- a/mm/kasan/kasan.h
+++ b/mm/kasan/kasan.h
@@ -241,6 +241,32 @@ static inline const void *arch_kasan_set_tag(const void 
*addr, u8 tag)
 #define reset_tag(addr)                ((void *)arch_kasan_reset_tag(addr))
 #define get_tag(addr)          arch_kasan_get_tag(addr)
 
+#ifdef CONFIG_KASAN_HW_TAGS
+
+#ifndef arch_enable_tagging
+#define arch_enable_tagging()
+#endif
+#ifndef arch_init_tags
+#define arch_init_tags(max_tag)
+#endif
+#ifndef arch_get_random_tag
+#define arch_get_random_tag()  (0xFF)
+#endif
+#ifndef arch_get_mem_tag
+#define arch_get_mem_tag(addr) (0xFF)
+#endif
+#ifndef arch_set_mem_tag_range
+#define arch_set_mem_tag_range(addr, size, tag) ((void *)(addr))
+#endif
+
+#define hw_enable_tagging()                    arch_enable_tagging()
+#define hw_init_tags(max_tag)                  arch_init_tags(max_tag)
+#define hw_get_random_tag()                    arch_get_random_tag()
+#define hw_get_mem_tag(addr)                   arch_get_mem_tag(addr)
+#define hw_set_mem_tag_range(addr, size, tag)  arch_set_mem_tag_range((addr), 
(size), (tag))
+
+#endif /* CONFIG_KASAN_HW_TAGS */
+
 /*
  * Exported functions for interfaces called from assembly or from generated
  * code. Declarations here to avoid warning about missing declarations.
-- 
2.29.2.222.g5d2a92d10f8-goog

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