[mm,v10,33/42] arm64: kasan: Add arch layer for memory tagging helpers

Commit Message

Andrey Konovalov Nov. 13, 2020, 10:16 p.m. UTC

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

Patch

diff --git a/arch/arm64/include/asm/memory.h b/arch/arm64/include/asm/memory.h
index 556cb2d62b5b..3bc08e6cf82e 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_kernel()
+#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 3b349a6e799d..bc4f28156157 100644
--- a/mm/kasan/kasan.h
+++ b/mm/kasan/kasan.h
@@ -243,6 +243,32 @@  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.