UPT_BX             14 arch/x86/um/asm/ptrace.h #define PT_REGS_BX(r) UPT_BX(&(r)->regs)
UPT_BX             15 arch/x86/um/shared/sysdep/ptrace_32.h #define UPT_SYSCALL_ARG1(r) UPT_BX(r)