diff --git a/arch/arm/include/asm/memory.h b/arch/arm/include/asm/memory.h index 4dd21457ef9d2b..9ecccc865046a2 100644 --- a/arch/arm/include/asm/memory.h +++ b/arch/arm/include/asm/memory.h @@ -226,7 +226,14 @@ static inline phys_addr_t __virt_to_phys(unsigned long x) static inline unsigned long __phys_to_virt(phys_addr_t x) { unsigned long t; - __pv_stub(x, t, "sub", __PV_BITS_31_24); + + /* + * 'unsigned long' cast discard upper word when + * phys_addr_t is 64 bit, and makes sure that inline + * assembler expression receives 32 bit argument + * in place where 'r' 32 bit operand is expected. + */ + __pv_stub((unsigned long) x, t, "sub", __PV_BITS_31_24); return t; }