KCOV_REMOTE_REGISTER(9)

💅 kcov_remote_register(9) 💅

okay so welcome to the Kernel Developer's Manual, bestie — this is the page for kcov_remote_register(9) and its whole remote code-coverage squad. It's giving kernel subsystem group chat, and honestly? iconic. 🦋

✨ NAME ✨

Say hi to kcov_remote_register, kcov_remote_unregister, kcov_remote_enter, and kcov_remote_leave — together they're the remote kernel code coverage collection interface. periodt. 💖

🌸 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 are the interface for collecting 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. highkey a whole vibe. 🫶

• kcov_remote_register(int subsystem, void *id) — registers a new instance of the given subsystem. Calling this function more than once with the same arguments is idempotent, so bestie, same args = same result, no drama. ✨
• kcov_remote_unregister(int subsystem, void *id) — 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. It's literally waiting for everybody to exit the group chat. 😭
• kcov_remote_enter(int subsystem, void *id) — enters a remote section. If the current thread has kcov(4) enabled, code coverage will be collected inside the remote section. Remote sections may not be nested — do not stack them, bestie, that's forbidden stacking energy 💀.
• kcov_remote_leave(int subsystem, void *id) — leaves a remote section. bye bestie! 👋

🧚 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. slay for flexibility. 🔥

🔥 CODE REFERENCES 🔥

These functions are implemented in sys/dev/kcov.c. go look, it's right there. 👑

🌈 SEE ALSO 🌈

• kcov(4)

👑 HISTORY 👑

These functions first appeared in OpenBSD 6.8. a classic, no cap. 💜

🫶 AUTHORS 🫶

Anton Lindqvist <anton@openbsd.org>

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okay that's the tea ☕ — this page is from Debian, dated February 1, 2021, and yes bestie, it's the KCOV_REMOTE_REGISTER(9) manual page. mwah 💋🎀