freebsd-src/sys

FreeBSD Kernel Source:

This directory contains the source files and build glue that make up the FreeBSD kernel and its modules, including both original and contributed software.

Kernel configuration files are located in the conf/ subdirectory of each architecture. GENERIC is the configuration used in release builds. NOTES contains documentation of all possible entries. LINT is a compile-only configuration used to maximize build coverage and detect regressions.

Source Roadmap:

Directory	Description
amd64	AMD64 (64-bit x86) architecture support
arm	32-bit ARM architecture support
arm64	64-bit ARM (AArch64) architecture support
cam	Common Access Method storage subsystem - cam(4) and ctl(4)
cddl	CDDL-licensed optional sources such as DTrace
conf	kernel build glue
compat	Linux compatibility layer, FreeBSD 32-bit compatibility
contrib	3rd-party imported software such as OpenZFS
crypto	crypto drivers
ddb	interactive kernel debugger - ddb(4)
fs	most filesystems, excluding UFS, NFS, and ZFS
dev	device drivers
gdb	kernel remote GDB stub - gdb(4)
geom	GEOM framework - geom(4)
i386	i386 (32-bit x86) architecture support
kern	main part of the kernel
libkern	libc-like and other support functions for kernel use
modules	kernel module infrastructure
net	core networking code
net80211	wireless networking (IEEE 802.11) - net80211(4)
netgraph	graph-based networking subsystem - netgraph(4)
netinet	IPv4 protocol implementation - inet(4)
netinet6	IPv6 protocol implementation - inet6(4)
netipsec	IPsec protocol implementation - ipsec(4)
netpfil	packet filters - ipfw(4), pf(4), and ipfilter(4)
opencrypto	OpenCrypto framework - crypto(7)
powerpc	PowerPC/POWER (32 and 64-bit) architecture support
riscv	64-bit RISC-V architecture support
security	security facilities - audit(4) and mac(4)
sys	kernel headers
tests	kernel unit tests
ufs	Unix File System - ffs(7)
vm	virtual memory system
x86	code shared by AMD64 and i386 architectures