NAME

kcov_remote_register, kcov_remote_unregister, kcov_remote_enter, kcov_remote_leave — remote kernel code coverage collection interface

SYNOPSIS

#include <sys/kcov.h>

void
kcov_remote_register(int subsystem, void *id);

void
kcov_remote_unregister(int subsystem, void *id);

void
kcov_remote_enter(int subsystem, void *id);

void
kcov_remote_leave(int subsystem, void *id);

DESCRIPTION

These functions provide an interface to collect code coverage from various kernel subsystems using kcov(4). The subsystem must be one of the following:

#define KCOV_REMOTE_COMMON
  0

The id must be a unique identifier for a resource tied to subsystem that is known both by kernel and user space. For instance, a network interface driver could form a subsystem using the unique interface identifier as the id.

kcov_remote_register() registers a new instance of the given subsystem. Calling this function more than once with the same arguments is idempotent.

kcov_remote_unregister() unregisters an existing instance of the given subsystem, if present. If one or many threads are currently within a remote section, kcov_remote_unregister() will sleep until all the sections have been left.

kcov_remote_enter() enters a remote section. If the current thread has kcov(4) enabled, code coverage will collected inside the remote section. Remote sections may not be nested.

kcov_remote_leave() leaves a remote section.

CONTEXT

kcov_remote_register() and kcov_remote_unregister() can be called from process context. kcov_remote_enter() and kcov_remote_leave() can be called from interrupt and process context.

CODE REFERENCES

These functions are implemented in sys/dev/kcov.c.

HISTORY

These functions first appeared in OpenBSD 6.8.

AUTHORS

Anton Lindqvist <anton@openbsd.org>