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From:   Andrey Konovalov <andreyknvl@google.com>
To:     Andrey Ryabinin <aryabinin@virtuozzo.com>,
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        Chintan Pandya <cpandya@codeaurora.org>,
        Vishwath Mohan <vishwath@google.com>,
        Andrey Konovalov <andreyknvl@google.com>
Subject: [PATCH v12 11/25] kasan, arm64: untag address in _virt_addr_is_linear
Date:   Tue, 27 Nov 2018 17:55:29 +0100
Message-Id: <dd9cda296c70ca6b1839cf4de3ee3137cf5030e7.1543337629.git.andreyknvl@google.com>
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virt_addr_is_linear (which is used by virt_addr_valid) assumes that the
top byte of the address is 0xff, which isn't always the case with
tag-based KASAN.

This patch resets the tag in this macro.

Reviewed-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Reviewed-by: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
---
 arch/arm64/include/asm/memory.h | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/arch/arm64/include/asm/memory.h b/arch/arm64/include/asm/memory.h
index 83c1366a1233..5fe2353f111b 100644
--- a/arch/arm64/include/asm/memory.h
+++ b/arch/arm64/include/asm/memory.h
@@ -322,9 +322,10 @@ static inline void *phys_to_virt(phys_addr_t x)
 #endif
 #endif
 
-#define _virt_addr_is_linear(kaddr)	(((u64)(kaddr)) >= PAGE_OFFSET)
-#define virt_addr_valid(kaddr)		(_virt_addr_is_linear(kaddr) && \
-					 _virt_addr_valid(kaddr))
+#define _virt_addr_is_linear(kaddr)	\
+	(__tag_reset((u64)(kaddr)) >= PAGE_OFFSET)
+#define virt_addr_valid(kaddr)		\
+	(_virt_addr_is_linear(kaddr) && _virt_addr_valid(kaddr))
 
 #include <asm-generic/memory_model.h>
 
-- 
2.20.0.rc0.387.gc7a69e6b6c-goog