arm64: Do not pass tagged addresses to __is_lm_address()

Commit 519ea6f1 ("arm64: Fix kernel address detection of
__is_lm_address()") fixed the incorrect validation of addresses below
PAGE_OFFSET. However, it no longer allowed tagged addresses to be passed
to virt_addr_valid().

Fix this by explicitly resetting the pointer tag prior to invoking
__is_lm_address(). This is consistent with the __lm_to_phys() macro.

Fixes: 519ea6f1 ("arm64: Fix kernel address detection of __is_lm_address()")
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Ard Biesheuvel <ardb@kernel.org>
Cc: <stable@vger.kernel.org> # 5.4.x
Cc: Will Deacon <will@kernel.org>
Cc: Vincenzo Frascino <vincenzo.frascino@arm.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Link: https://lore.kernel.org/r/20210201190634.22942-2-catalin.marinas@arm.com

arch/arm64/include/asm/memory.h

@@ -332,7 +332,7 @@ static inline void *phys_to_virt(phys_addr_t x)
 #endif /* !CONFIG_SPARSEMEM_VMEMMAP || CONFIG_DEBUG_VIRTUAL */
 
 #define virt_addr_valid(addr)	({					\
-	__typeof__(addr) __addr = addr;					\
+	__typeof__(addr) __addr = __tag_reset(addr);			\
 	__is_lm_address(__addr) && pfn_valid(virt_to_pfn(__addr));	\
 })
 

arch/arm64/mm/physaddr.c

@@ -9,7 +9,7 @@
 
 phys_addr_t __virt_to_phys(unsigned long x)
 {
-	WARN(!__is_lm_address(x),
+	WARN(!__is_lm_address(__tag_reset(x)),
 	     "virt_to_phys used for non-linear address: %pK (%pS)\n",
 	      (void *)x,
 	      (void *)x);