An arch that has done all these things sets
CONFIG_HAVE_ARCH_TRACEHOOK.
This is required to enable the utrace code.
An arch defines these in <asm/ptrace.h>
if it supports hardware single-step or block-step features.
An arch provides <asm/syscall.h> that
defines these as inlines, or declares them as exported functions.
These interfaces are described in the section called “System Call Tracing”.
An arch must define TIF_NOTIFY_RESUME
and TIF_SYSCALL_TRACE
in its <asm/thread_info.h>.
The arch code must call the following functions, all declared
in <linux/tracehook.h> and
described in the section called “Core Calls In”:
tracehook_notify_resume
tracehook_report_syscall_entry
tracehook_report_syscall_exit
tracehook_signal_handler