mbr_magic 44 arch/x86/boot/edd.c u16 mbr_magic; mbr_magic 67 arch/x86/boot/edd.c mbr_magic = *(u16 *)&mbrbuf_ptr[510]; mbr_magic 70 arch/x86/boot/edd.c return mbr_magic == 0xAA55 ? 0 : -1;