Subject: [PATCH 1/8] arm64: memory: Fix virt_addr_valid() using __is_lm_address()

From: Will Deacon <[email-masked]>
Date: Tue, 13 Aug 2019 18:01:42 +0100

virt_addr_valid() is intended to test whether or not the passed address
is a valid linear map address. Unfortunately, it relies on
_virt_addr_is_linear() which is broken because it assumes the linear
map is at the top of the address space, which it no longer is.

Reimplement virt_addr_valid() using __is_lm_address() and remove
_virt_addr_is_linear() entirely. At the same time, ensure we evaluate
the macro parameter only once and move it within the __ASSEMBLY__ block.

Reported-by: Qian Cai <[email-masked]>
Reported-by: Geert Uytterhoeven <[email-masked]>
Fixes: 14c127c957c1 ("arm64: mm: Flip kernel VA space")
Signed-off-by: Will Deacon <[email-masked]>
---
 arch/arm64/include/asm/memory.h | 14 +++++++-------
 1 file changed, 7 insertions(+), 7 deletions(-)

diff --git a/arch/arm64/include/asm/memory.h b/arch/arm64/include/asm/memory.h
index afaf512c0e1b..442ab861cab8 100644
--- a/arch/arm64/include/asm/memory.h
+++ b/arch/arm64/include/asm/memory.h
@@ -244,9 +244,9 @@ static inline const void *__tag_set(const void *addr, u8 tag)
 /*
  * The linear kernel range starts in the middle of the virtual adddress
  * space. Testing the top bit for the start of the region is a
- * sufficient check.
+ * sufficient check and avoids having to worry about the tag.
  */
-#define __is_lm_address(addr)	(!((addr) & BIT(vabits_actual - 1)))
+#define __is_lm_address(addr)	(!(((u64)addr) & BIT(vabits_actual - 1)))
 
 #define __lm_to_phys(addr)	(((addr) + physvirt_offset))
 #define __kimg_to_phys(addr)	((addr) - kimage_voffset)
@@ -326,13 +326,13 @@ static inline void *phys_to_virt(phys_addr_t x)
 
 #define virt_to_page(vaddr)	((struct page *)((__virt_to_pgoff(vaddr)) + VMEMMAP_START))
 #endif
-#endif
 
-#define _virt_addr_is_linear(kaddr)	\
-	(__tag_reset((u64)(kaddr)) >= PAGE_OFFSET)
+#define virt_addr_valid(addr)	({					\
+	__typeof__(addr) __addr = addr;					\
+	__is_lm_address(__addr) && pfn_valid(virt_to_pfn(__addr));	\
+})
 
-#define virt_addr_valid(kaddr)		\
-	(_virt_addr_is_linear(kaddr) && pfn_valid(virt_to_pfn(kaddr)))
+#endif
 
 /*
  * Given that the GIC architecture permits ITS implementations that can only be
-- 
2.11.0

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