poky: subtree update:c67f57c09e..c6bc20857c
Adrian Freihofer (2):
oe-publish-sdk: fix layers init via ssh
oe-publish-sdk: add --keep-orig option
Alexander Kanavin (68):
meta-selftest: correct the virgl test for 5.8 kernels
bison: upgrade 3.6.4 -> 3.7.1
util-linux: upgrade 2.35.2 -> 2.36
python3-numpy: upgrade 1.19.0 -> 1.19.1
python3-setuptools: upgrade 49.3.1 -> 49.6.0
rsync: upgrade 3.2.2 -> 3.2.3
util-linux: merge .inc into .bb
acpica: upgrade 20200528 -> 20200717
asciidoc: upgrade 9.0.1 -> 9.0.2
cryptodev: upgrade 1.10 -> 1.11
diffoscope: upgrade 153 -> 156
epiphany: upgrade 3.36.3 -> 3.36.4
font-alias: upgrade 1.0.3 -> 1.0.4
gtk+3: upgrade 3.24.21 -> 3.24.22
libcheck: upgrade 0.15.0 -> 0.15.2
libinput: upgrade 1.16.0 -> 1.16.1
libpipeline: upgrade 1.5.2 -> 1.5.3
libx11: upgrade 1.6.9 -> 1.6.11
linux-firmware: upgrade 20200619 -> 20200721
man-pages: upgrade 5.07 -> 5.08
mc: upgrade 4.8.24 -> 4.8.25
mesa: upgrade 20.1.4 -> 20.1.5
piglit: upgrade to latest revision
re2c: upgrade 2.0 -> 2.0.2
sysstat: upgrade 12.2.2 -> 12.4.0
vala: upgrade 0.48.7 -> 0.48.9
bootchart2: update 0.14.8 -> 0.14.9
harfbuzz: convert to meson, enable gobject introspection
pango: update 1.44.7 -> 1.46.0
boost: update 1.73.0 -> 1.74.0
xev: update 1.2.3 -> 1.2.4
wpebackend-fdo: update 1.6.1 -> 1.7.1
gpgme: update 1.13.1 -> 1.14.0
libpsl: update 0.21.0 -> 0.21.1.
gettext: update 0.20.2 -> 0.21
cmake: update 3.17.3 -> 3.18.1
linux-firmware: update 20200721 -> 20200817
meson: update 0.55.0 -> 0.55.1
systemd-boot: bump version to 246.2
json-glib: inherit upstream-version-is-even
packagegroup-core-device-devel: remove
oeqa/x32lib: rework to use readelf from the host
oeqa/multilib: rework to use readelf from the host
oeqa/multilib: un-skip the connman test
poky.conf: do not install packagegroup-core-device-devel into qemu images
glib-2.0: update 2.64.4 -> 2.64.5
cmake: upgrade 3.18.1 -> 3.18.2
libxcrypt: upgrade 4.4.16 -> 4.4.17
debianutils: upgrade 4.11 -> 4.11.1
enchant2: upgrade 2.2.8 -> 2.2.9
harfbuzz: upgrade 2.7.1 -> 2.7.2
libmpc: upgrade 1.1.0 -> 1.2.0
librepo: upgrade 1.12.0 -> 1.12.1
libuv: upgrade 1.38.1 -> 1.39.0
msmtp: upgrade 1.8.11 -> 1.8.12
ninja: upgrade 1.10.0 -> 1.10.1
p11-kit: upgrade 0.23.20 -> 0.23.21
pango: upgrade 1.46.0 -> 1.46.1
re2c: upgrade 2.0.2 -> 2.0.3
resolvconf: upgrade 1.82 -> 1.83
stress-ng: upgrade 0.11.18 -> 0.11.19
gnu-config: update to latest revision
nasm: update 2.15.03 -> 2.15.05
libva-utils: fix upstream version check
gnupg: update 2.2.21 -> 2.2.22
libx11: update 1.6.11 -> 1.6.12
mesa: update 20.1.5 -> 20.1.6
xserver-xorg: update 1.20.8 -> 1.20.9
Andrey Zhizhikin (1):
insane: check for missing update-alternatives inherit
Anibal Limon (1):
recipes-kernel: linux-firmware add qcom-venus-{5.2,5.4} packages
Aníbal Limón (1):
recipes-graphics/xorg-xserver: Add patch to fix segfault when probe
Armin Kuster (2):
bind: update to 9.11.22 ESV
core-image-sato: qemumips use 512 mem
Bruce Ashfield (30):
linux-yocto/5.4: update to v5.4.59
linux-yocto/5.8: update to v5.8.2
yocto-bsp: update to v5.4.56
yocto-bsp: update to v5.4.58
qemu: bump default reference kernel to v5.8
linux-yocto/5.8: fix perf and virtio_scsi warnings
linux-yocto-rt/5.8: fix lttng-modules build
linux-yocto/5.8: selftests/bpf: Prevent runqslower from racing on building bpftool
linux-yocto/5.8: disable CONFIG_NFS_DISABLE_UDP_SUPPORT
poky: set preferred version for linux-yocto to be v5.8
poky-tiny: set preferred version to 5.8
poky: add preferred version for linux-yocto-rt
linux-yocto/5.8: update to v5.8.3
linux-yocto/5.4: update to v5.4.60
kernel: config cleanups for 5.8+
linux-yocto/5.4: update to v5.4.61
linux-yocto/5.8: update to v5.8.4
linux-yocto/5.8: disable IKHEADERS in default builds
kernel-yocto: allow promotion of configuration warnings to errors
kernel-yocto: checksum all modifications to available kernel fragments directories
lttng-modules/devupstream: bump to latest 2.12 commits
linux-yocto-dev: bump to v5.9+
linux-yocto/5.8: update to v5.8.5
kernel-devsrc: account for HOSTCC and HOSTCXX
linux-yocto/config: netfilter: Enable nat for ipv4 and ipv6
linux-yocto/5.8: update to v5.8.8
linux-yocto/5.4: update to v5.4.64
linux-yocto/config: configuration warning cleanup
linux-yocto/5.8: update to v5.8.9
linux-yocto/5.4: update to v5.4.65
Changhyeok Bae (2):
iw: upgrade 5.4 -> 5.8
iputils: upgrade s20190709 -> s20200821
Chris Laplante (12):
bitbake: compat.py: remove file since it no longer actually implements anything
bitbake: COW: formatting
bitbake: COW: migrate test suite into tests/cow
cve-update-db-native: add progress handler
cve-check/cve-update-db-native: use lockfile to fix usage under multiconfig
cve-update-db-native: use context manager for cve_f
cve-check: avoid FileNotFoundError if no do_cve_check task has run
bitbake: utils: process_profilelog: use context manager
bitbake: utils: fix UnboundLocalError when _print_exception raises
cve-update-db-native: be less magical about checking whether the cve-check class is enabled
cve-update-db-native: move -journal checking into do_fetch
cve-update-db-native: remove unused variable
Christophe GUIBOUT (1):
initramfs-framework: support kernel cmdline with double quotes
Denys Dmytriyenko (2):
weston: upgrade 8.0.0 -> 9.0.0
cryptodev: bump 1 commit past 1.11 to fix 5.9-rc1+
Diego Sueiro (2):
license_image.bbclass: Create symlink to the image license manifest dir
license_image.bbclass: Fix symlink to the image license manifest dir creation
Douglas Royds (1):
tcmode-default: Drop gcc-cross-initial, gcc-crosssdk-initial references
Frazer Clews (1):
bitbake: lib: fix most undefined code picked up by pylint
Geoff Parker (1):
systemd-serialgetty: Replace sed quoting using ' with " to allow var expansion
Jacob Kroon (1):
gcc10: Don't default back to -fcommon
Jean-Francois Dagenais (1):
bitbake: siggen: clean_basepath: remove recipe full path when virtual:xyz present
Jens Rehsack (1):
lttng-modules: backport patches from 2.12.x to fix 5.4.64+ and 5.8.9+ builds
Joe Slater (1):
pseudo: fix renaming to self
Jon Mason (4):
cortex-m0plus.inc: change file permissions
tune-cortexa55.inc: clean-up ARMv8.2a uses
tune-cortexa57-cortexa53.inc: add CRC and set march
tune-cortexa*: Cleanups
Joshua Watt (8):
wic: Add 512 Byte alignment to --offset
oeqa: runtime_tests: Extra GPG debugging
oeqa: sdk: Capture stderr output
oeqa: reproducible: Fix test not producing diffs
diffoscope: upgrade 156 -> 158
bitbake: bitbake: Add parsing torture test
bitbake: cooker: Block SIGINT in worker processes
sphinx: dev-manual: Clarify that virtual providers do not apply to runtime dependencies
Kai Kang (1):
dhcpcd: 9.1.4 -> 9.2.0
Kevin Hao (1):
meta-yocto-bsp: Bump to the v5.8 kernel
Khairul Rohaizzat Jamaluddin (1):
wic/bootimg-efi: IMAGE_EFI_BOOT_FILES variable added to separate bootimg-efi and bootimg-partition
Khem Raj (24):
gcc-cross-canadian: Install gcc/g++ wrappers for musl
uninative: Upgrade to 2.9
packagegroup-core-tools-profile: Disable lttng-modules for riscv64
lttng-modules: Disable on riscv64
kexec-tools: Fix build with -fno-common on ppc
lttng-tools: Do not build for riscv64
util-linux: Allow update alternatives for additional apps
lttng-tools: lttng-ust works on riscv64
json-glib: Backport a build fix with clang
rpcbind: Use update-alternatives for rpcinfo
go: Upgrade to 1.15 major release
weston-init: Redefine weston service and add socket activation option
musl: Upgrade to latest master
libucontext: Recognise riscv32 architecture
linuxloader.bbclass: Define riscv32 ldso for musl
populate_sdk_ext: Do not assume local.conf will always exist
weston: plane_add_prop() calls break musl atomic modesetting
weston-init: Enable RDP screen share
weston-init: Do not use fbdev backend
weston-init: Select drm/fbdev backends for qemu machines
oeqa/weston: Fix tests to run with systemd
core-image-weston: Bump qemu memory to 512M
go: Update to 1.15.2 minor release
bind: Inherit update-alternatives
Mark Hatle (6):
package_tar.bbclass: Sync to the other package_* classes
kernel.bbclass: Remove do_install[prefunc] no longer needed
buildhistory.bbclass: Rework to use read_subpackage_metadata
kernel.bbclass: Move away from calling package_get_auto_pr
package.bbclass: hash equivalency and pr service
bitbake: process.py: Handle SystemExit exception to eliminate backtrace
Mark Morton (1):
sphinx: test-manual code block, link, and format update
Martin Jansa (7):
devtool: expand SRC_URI when guessing recipe update mode
image-artifact-names: introduce new bbclass and move some variables into it
kernel.bbclass: use bash variables like imageType, base_name without {}
kernel.bbclass: eliminate (initramfs_)symlink_name variables
kernel.bbclass: use camelCase notation for bash variables in do_deploy
*-initramfs: don't use .rootfs IMAGE_NAME_SUFFIX
bitbake.conf: use ${TCMODE}-${TCLIBC} directory for CACHE
Matt Madison (1):
image.bbclass: fix REPRODUCIBLE_TIMESTAMP_ROOTFS reference
Michael Gloff (2):
sysvinit rc: Use PSPLASH_FIFO_DIR for progress fifo
sysvinit: Remove ${B} assignment
Michael Tretter (1):
devtool: deploy-target: Fix size calculation for hard links
Ming Liu (2):
systemd: split systemd specific udev rules into its own package
libubootenv: inherit uboot-config
Mingli Yu (3):
qemu: always define unknown_lock_type
qemu: override DEBUG_BUILD
bison: remove the parallel build patch
Naveen Saini (1):
lib/oe/recipeutils.py: add support for BBFILES_DYNAMIC
Nicolas Dechesne (73):
linux-libc-headers: kernel headers are installed in STAGING_KERNEL_BUILDDIR
bitbake: sphinx: add initial build infrastructure
bitbake: sphinx: initial sphinx support
bitbake: sphinx: bitbake-user-manual: use builtin sphinx glossary
bitbake: sphinx: switch to readthedocs theme
bitbake: sphinx: override theme CSS
bitbake: sphinx: fixup for links
bitbake: sphinx: fix links inside notes
bitbake: sphinx: fixes all remaining warnings
bitbake: sphinx: Makefile.sphinx: add clean and publish targets
bitbake: sphinx: tweak html output a bit
bitbake: sphinx: add SPDX headers
bitbake: sphinx: index: move the boilerplate at the end of the page
bitbake: sphinx: conf: enable extlinks extension
bitbake: sphinx: add releases page
bitbake: sphinx: bitbake-user-manual: insert additional blank line after title
bitbake: sphinx: last manual round of fixes/improvements
bitbake: sphinx: update style for important, caution and warnings
bitbake: sphinx: remove leading '/'
bitbake: sphinx: theme_override: properly set font for verbatim text
bitbake: bitbake-user-manual: fix bad links
sphinx: add initial build infrastructure
sphinx: initial sphinx support
sphinx: ref-variables: use builtin sphinx glossary
sphinx: overview-manual: add figures
sphinx: switch to readthedocs theme
sphinx: Add SPDX license headers
sphinx: add CSS theme override
sphinx: bsp-guide: add figures
sphinx: add Yocto project logo
sphinx: conf: update copyright
sphinx: conf: add substitutions/global variables
sphinx: add boilerplate file
sphinx: add boilerplate to manuals
sphinx: ref-manual: add revision history table
sphinx: add a general index
sphinx: conf.py: enable sphinx.ext.autosectionlabel
sphinx: ref-manual: use builtin glossary for the Terms section
sphinx: fix internal links
sphinx: ref-manual: fix typo
sphinx: fix custom term links
sphinx: manual updates for some links
sphinx: dev-manual add figures
sphinx: kernel-dev: add figures
sphinx: profile-manual: add figures
sphinx: fix up bold text for informalexample container
sphinx: ref-manual: add figures
sphinx: sdk-manual: add figures
sphinx: test-manual: add figures
sphinx: toaster-manual: add figures
sphinx: add links for Yocto project website
sphinx: fix links when the link text should be displayed
sphinx: add links to terms in the BitBake glossary
sphinx: add links to section in the Bitbake manual
sphinx: setup extlink for docs.yoctoproject.org
sphinx: enable intersphinx extension
sphinx: insert blank below between title and toc
sphinx: fix up terms related to kernel-fitimage
sphinx: conf: a few rendering tweaks
sphinx: makefile: add publish target
sphinx: conf: include CSS/JS files, the proper way
sphinx: convert 'what I wish I'd known'
sphinx: convert 'transitioning to a custom environment'
sphinx: ref-manual: fix heading for oe-init-build-env
sphinx: brief-yoctoprojectqs: fix up all remaining rendering issues
sphinx: Makefile.sphinx improvements
sphinx: convert bsp-guide
sphinx: remove leading '/'
sphinx: update style for important, caution and warnings
sphinx: profile-manual: convert profile-manual
sphinx: theme_override: properly set font for verbatim text
sphinx: theme_override: add tying-it-together admonition
sphinx: conf: exclude adt-manual/*.rst
Oleksandr Kravchuk (1):
ell: update to 0.33
Ovidiu Panait (1):
libxml2: Fix CVE-2020-24977
Peter A. Bigot (2):
bluez5: fix builds that require ell support
timezone: include leap second data in tzdata-core
Peter Bergin (1):
systemd: avoid failing if no udev rules provided
Pierre-Jean Texier (2):
libubootenv: upgrade 0.3 -> 0.3.1
diffoscope: upgrade 158 -> 160
Quentin Schulz (16):
sphinx: brief-yoctoprojectqs: remove redundant welcome
sphinx: brief-yoctoprojectqs: fix ambiguous note for cyclone5 example
sphinx: brief-yoctoprojectqs: add missing boilerplate
sphinx: overview-manual: add link to AUH how-to section
sphinx: overview-manual: fix bitbake basic explanation
sphinx: brief-yoctoprojectqs: add note on branch consistency between layers
sphinx: what-i-wish-id-known: update "don't be fooled by doc search results"
sphinx: overview-manual: remove highlight in bold section
sphinx: replace special quotes with single and double quotes
sphinx: fix incorrect indentations
sphinx: brief-yoctoprojectqs: put other distros note after Ubuntu-specific packages
sphinx: fix a few typos or missing/too many words
sphinx: "highlight" some variables, tasks or files
sphinx: fix or add missing links and remove mention of Eclipse workflow
ref-manual: examples: hello-autotools: upgrade to 2.10
ref-manual: examples: libxpm: add relative path to .inc
Rahul Kumar (1):
systemd-serialgetty: Fix sed expression quoting
Rasmus Villemoes (1):
kernel.bbclass: run do_symlink_kernsrc before do_patch
Richard Purdie (74):
nativesdk-sdk-provides-dummy: Add /bin/sh
bitbake: fetch2/wget: Remove buffering parameter
bitbake: cooker: Ensure parse_quit thread is closed down
bitbake: cooker: Explictly shut down the sync thread
bitbake: fetch2: Drop cups.org from wget status checks
bitbake: build/msg: Cleanup verbose option handling
bitbake: cooker/cookerdata/main: Improve loglevel handling
bitbake: cookerdata: Ensure UI options are updated to the server
bitbake: cooker/cookerdata: Ensure UI event log is updated from commandline
bitbake: cooker: Defer configuration init to after UI connection
bitbake: server/process: Move the socket code to server process only
bitbake: main/server/process: Drop configuration object passing
bitbake: cooker: Ensure BB_ORIGENV is updated by changes to configuration.env
bitbake: server/process: Log extra threads at exit
bitbake: server/process: Add bitbake-server and exec() a new server process
bitbake: runqueue: Don't use sys.argv
bitbake: cooker: Ensure cooker's enviroment is updated on updateConfig
connman-gnome/matchbox-desktop: Remove file:// globbing
selftest/recipetool: Drop globbing SRC_URI test, no longer supported
local.conf.sample: Document memory resident bitbake
bitbake: fetch2: Drop globbing supprt in file:// SRC_URIs
bitbake: server/process: Use sys.executable for bitbake-server
bitbake: process: Avoid bb.utils.timeout
bitbake: utils: Drop broken timeout function
bitbake: server/process: Fix typo in code causing tracebacks
oeqa/selftest: Apply patch to fix cpio build with -fno-common
runqemu: Show an error for conflicting graphics options
lttng: Move platform logic to dedicated inc file
patchelf: upgrade 0.11 -> 0.12
build-appliance/packagegroup-core-base-utils: Replace dhcp-client/dhcp-server with dhcpcd/kea
selftest/prservice: Improve test failure message
iputils: Adapt ${PN}-tftpd package dependency to PACKAGECONFIG
bitbake: process/knotty: Improve early exception handling
bitbake: cooker/cookerdata: Use BBHandledException, not sys.exit()
bitbake: cookerdata: Fix exception raise statements
bitbake: process: Avoid printing binary strings for leftover processes
bitbake: server/process: Ensure logging is flushed
bitbake: server/process: Don't show tracebacks if the lockfile is removed
bitbake: cooker: Ensure parser replacement calls parser final_cleanup
bitbake: cooker: Assign a name to the sync thread to aid debugging
bitbake: server/process: Ensure we don't keep looping if some other server is started
bitbake: server/process: Prefix the log data with pid/time information
bitbake: server/process: Note when commands complete in logs
bitbake: cooker: Ensure parser is cleaned up
runqemu: Add a hook to allow it to renice
bitbake: cooker: Avoid parser deadlocks
bitbake: cooker: Ensure parser worker signal handlers are default
selftest/signing: Ensure build path relocation is safe
oeqa/concurrencytest: Improve builddir path manipulations
bitbake: cooker/command: Fix disconnection handling
bitbake: tinfoil: Ensure sockets don't leak even when exceptions occur
bitbake: tests/fetch: Move away from problematic freedesktop.org urls
bitbake: sphinx: Enhance the sphinx experience/nagivation with:
bitbake: sphinx: theme_override: Use bold for emphasis text
Revert "qemu: always define unknown_lock_type"
Revert "core-image-sato: qemumips use 512 mem"
sphinx: Organize top level docs
sphinx: releases.rst: Add index/links to docs for previous releases
sphinx: boilerplate.rst: Drop versions notes as we have better navigation now
sphinx: boilerplate.rst: Sphinx puts the copyright elsewhere
sphinx: history: Move revision history to its own section
sphinx: manuals: Move boilerplate after toctree
sphinx: Add support for multiple docs version
sphinx: index.rst: Fix links
sphinx: ref-system-requirements: Improve formatting of the notes sections, merging them
sphinx: ref-manual links fixes and many other cleanups to import
sphinx: dev-manual: Various URL, code block and other fixes to imported data
sphinx: sdk-manual: Various URL, code block and other fixes to imported data
sphinx: kernel-dev: Various URL, code block and other fixes to imported data
sphinx: theme_override: Use bold for emphasis text
sphinx: ref-tasks: Add populate_sdk_ext task definition
sphinx: ref-manual/migration: Split each release into its own file
sphinx: overview-manual: Various URL, code block and other fixes to imported data
build-appliance-image: Update to master head revision
Robert Yang (3):
bitbake: cooker.py: Save prioritized BBFILES to BBFILES_PRIORITIZED
bitbake: utils.py: get_file_layer(): Exit the loop when file is matched
bitbake: utils.py: get_file_layer(): Improve performance
Ross Burton (25):
package.bbclass: explode the RPROVIDES so we don't think the versions are provides
elfutils: silence a new QA warning
insane: improve gnu-hash-style warning
gdk-pixbuf: add tests PACKAGECONFIG
debianutils: change SRC_URI to use snapshot.debian.org
insane: only load real files as ELF
autoconf: consolidate SRC_URI
autoconf: consolidate DEPENDS
kea: no need to depend on kea-native
kea: don't use PACKAGECONFIG inappropriately
kea: bump to 1.7.10
help2man: rewrite recipe
local.conf.sample.extended: remove help2man reference
curl: add vendors to CVE_PRODUCT to exclude false positives
harfbuzz: update patch status
harfbuzz: fix a build race around hb-version.h
cmake: whitelist CVE-2016-10642
ncurses: remove config.cache
qemu: fix CVE-2020-14364
cve-update-db-native: remove unused import
cve-update-db-native: add more logging when fetching
cve-update-db-native: use fetch task
alsa-plugins: improve .la removal
sato-screenshot: improve .la removal
buildhistory-diff: use BUILDDIR to know where buildhistory is
Saul Wold (1):
gnupg: uprev 2.2.22 -> 2.2.23
Stacy Gaikovaia (2):
bison: uprev from 3.7.1 to 3.7.2
valgrind: fix memcheck vgtests remove fullpath-after flags
Steve Sakoman (1):
xinput-calibrator: change SRC_URI to branch with libinput support
Sumit Garg (1):
insane: fix gnu-hash-style check
TeohJayShen (1):
oeqa/runtime: add test for matchbox-terminal
Tim Orling (1):
sphinx: toaster-manual: fix vars, links, code blocks
Vijai Kumar K (2):
image_types_wic: Add ASSUME_PROVIDED to WICVARS
wic: misc: Add /bin to the list of searchpaths
Yanfei Xu (1):
kernel-yocto: only replace leading -I in include paths
Yi Zhao (1):
glib-networking: add ptest
Zhixiong Chi (1):
gnutls: CVE-2020-24659
akuster (8):
log4cplus: move meta-oe pkg to core
kea: Move from meta-networking
maintainers.inc: Add me as kea & log4plus maintainer.
dhcpcd: Move from meta-network as OE-Core needs a client
maintainers.inc: Add me as dhcpcd maintainer
dhcp: remove from core
bind: Add 9.16.x
bind: 9.11 remove
hongxu (1):
sysstat: fix installed-vs-shipped QA Issue in systemd
zangrc (4):
libcap:upgrade 2.42 -> 2.43
libcap-ng:upgrade 0.7.10 -> 0.7.11
libgpg-error:upgrade 1.38 -> 1.39
at-spi2-core:upgrade 2.36.0 -> 2.36.1
Signed-off-by: Andrew Geissler <geissonator@yahoo.com>
Change-Id: I5542f5eea751a2641342e945725fd687cd74bebe
diff --git a/poky/documentation/kernel-dev/kernel-dev-concepts-appx.rst b/poky/documentation/kernel-dev/kernel-dev-concepts-appx.rst
new file mode 100644
index 0000000..04cb117
--- /dev/null
+++ b/poky/documentation/kernel-dev/kernel-dev-concepts-appx.rst
@@ -0,0 +1,426 @@
+.. SPDX-License-Identifier: CC-BY-2.0-UK
+
+************************
+Advanced Kernel Concepts
+************************
+
+.. _kernel-big-picture:
+
+Yocto Project Kernel Development and Maintenance
+================================================
+
+Kernels available through the Yocto Project (Yocto Linux kernels), like
+other kernels, are based off the Linux kernel releases from
+http://www.kernel.org. At the beginning of a major Linux kernel
+development cycle, the Yocto Project team chooses a Linux kernel based
+on factors such as release timing, the anticipated release timing of
+final upstream ``kernel.org`` versions, and Yocto Project feature
+requirements. Typically, the Linux kernel chosen is in the final stages
+of development by the Linux community. In other words, the Linux kernel
+is in the release candidate or "rc" phase and has yet to reach final
+release. But, by being in the final stages of external development, the
+team knows that the ``kernel.org`` final release will clearly be within
+the early stages of the Yocto Project development window.
+
+This balance allows the Yocto Project team to deliver the most
+up-to-date Yocto Linux kernel possible, while still ensuring that the
+team has a stable official release for the baseline Linux kernel
+version.
+
+As implied earlier, the ultimate source for Yocto Linux kernels are
+released kernels from ``kernel.org``. In addition to a foundational
+kernel from ``kernel.org``, the available Yocto Linux kernels contain a
+mix of important new mainline developments, non-mainline developments
+(when no alternative exists), Board Support Package (BSP) developments,
+and custom features. These additions result in a commercially released
+Yocto Project Linux kernel that caters to specific embedded designer
+needs for targeted hardware.
+
+You can find a web interface to the Yocto Linux kernels in the
+:ref:`overview-manual/overview-manual-development-environment:yocto project source repositories`
+at :yocto_git:`/`. If you look at the interface, you will see to
+the left a grouping of Git repositories titled "Yocto Linux Kernel".
+Within this group, you will find several Linux Yocto kernels developed
+and included with Yocto Project releases:
+
+- *linux-yocto-4.1:* The stable Yocto Project kernel to use with
+ the Yocto Project Release 2.0. This kernel is based on the Linux 4.1
+ released kernel.
+
+- *linux-yocto-4.4:* The stable Yocto Project kernel to use with
+ the Yocto Project Release 2.1. This kernel is based on the Linux 4.4
+ released kernel.
+
+- *linux-yocto-4.6:* A temporary kernel that is not tied to any
+ Yocto Project release.
+
+- *linux-yocto-4.8:* The stable yocto Project kernel to use with
+ the Yocto Project Release 2.2.
+
+- *linux-yocto-4.9:* The stable Yocto Project kernel to use with
+ the Yocto Project Release 2.3. This kernel is based on the Linux 4.9
+ released kernel.
+
+- *linux-yocto-4.10:* The default stable Yocto Project kernel to
+ use with the Yocto Project Release 2.3. This kernel is based on the
+ Linux 4.10 released kernel.
+
+- *linux-yocto-4.12:* The default stable Yocto Project kernel to
+ use with the Yocto Project Release 2.4. This kernel is based on the
+ Linux 4.12 released kernel.
+
+- *yocto-kernel-cache:* The ``linux-yocto-cache`` contains patches
+ and configurations for the linux-yocto kernel tree. This repository
+ is useful when working on the linux-yocto kernel. For more
+ information on this "Advanced Kernel Metadata", see the
+ ":doc:`kernel-dev-advanced`" Chapter.
+
+- *linux-yocto-dev:* A development kernel based on the latest
+ upstream release candidate available.
+
+.. note::
+
+ Long Term Support Initiative (LTSI) for Yocto Linux kernels is as
+ follows:
+
+ - For Yocto Project releases 1.7, 1.8, and 2.0, the LTSI kernel is
+ ``linux-yocto-3.14``.
+
+ - For Yocto Project releases 2.1, 2.2, and 2.3, the LTSI kernel is
+ ``linux-yocto-4.1``.
+
+ - For Yocto Project release 2.4, the LTSI kernel is
+ ``linux-yocto-4.9``
+
+ - ``linux-yocto-4.4`` is an LTS kernel.
+
+Once a Yocto Linux kernel is officially released, the Yocto Project team
+goes into their next development cycle, or upward revision (uprev)
+cycle, while still continuing maintenance on the released kernel. It is
+important to note that the most sustainable and stable way to include
+feature development upstream is through a kernel uprev process.
+Back-porting hundreds of individual fixes and minor features from
+various kernel versions is not sustainable and can easily compromise
+quality.
+
+During the uprev cycle, the Yocto Project team uses an ongoing analysis
+of Linux kernel development, BSP support, and release timing to select
+the best possible ``kernel.org`` Linux kernel version on which to base
+subsequent Yocto Linux kernel development. The team continually monitors
+Linux community kernel development to look for significant features of
+interest. The team does consider back-porting large features if they
+have a significant advantage. User or community demand can also trigger
+a back-port or creation of new functionality in the Yocto Project
+baseline kernel during the uprev cycle.
+
+Generally speaking, every new Linux kernel both adds features and
+introduces new bugs. These consequences are the basic properties of
+upstream Linux kernel development and are managed by the Yocto Project
+team's Yocto Linux kernel development strategy. It is the Yocto Project
+team's policy to not back-port minor features to the released Yocto
+Linux kernel. They only consider back-porting significant technological
+jumps DASH and, that is done after a complete gap analysis. The reason
+for this policy is that back-porting any small to medium sized change
+from an evolving Linux kernel can easily create mismatches,
+incompatibilities and very subtle errors.
+
+The policies described in this section result in both a stable and a
+cutting edge Yocto Linux kernel that mixes forward ports of existing
+Linux kernel features and significant and critical new functionality.
+Forward porting Linux kernel functionality into the Yocto Linux kernels
+available through the Yocto Project can be thought of as a "micro
+uprev." The many "micro uprevs" produce a Yocto Linux kernel version
+with a mix of important new mainline, non-mainline, BSP developments and
+feature integrations. This Yocto Linux kernel gives insight into new
+features and allows focused amounts of testing to be done on the kernel,
+which prevents surprises when selecting the next major uprev. The
+quality of these cutting edge Yocto Linux kernels is evolving and the
+kernels are used in leading edge feature and BSP development.
+
+Yocto Linux Kernel Architecture and Branching Strategies
+========================================================
+
+As mentioned earlier, a key goal of the Yocto Project is to present the
+developer with a kernel that has a clear and continuous history that is
+visible to the user. The architecture and mechanisms, in particular the
+branching strategies, used achieve that goal in a manner similar to
+upstream Linux kernel development in ``kernel.org``.
+
+You can think of a Yocto Linux kernel as consisting of a baseline Linux
+kernel with added features logically structured on top of the baseline.
+The features are tagged and organized by way of a branching strategy
+implemented by the Yocto Project team using the Source Code Manager
+(SCM) Git.
+
+.. note::
+
+ - Git is the obvious SCM for meeting the Yocto Linux kernel
+ organizational and structural goals described in this section. Not
+ only is Git the SCM for Linux kernel development in ``kernel.org``
+ but, Git continues to grow in popularity and supports many
+ different work flows, front-ends and management techniques.
+
+ - You can find documentation on Git at
+ http://git-scm.com/documentation. You can also get an
+ introduction to Git as it applies to the Yocto Project in the
+ ":ref:`overview-manual/overview-manual-development-environment:git`" section in the Yocto Project
+ Overview and Concepts Manual. The latter reference provides an
+ overview of Git and presents a minimal set of Git commands that
+ allows you to be functional using Git. You can use as much, or as
+ little, of what Git has to offer to accomplish what you need for
+ your project. You do not have to be a "Git Expert" in order to use
+ it with the Yocto Project.
+
+Using Git's tagging and branching features, the Yocto Project team
+creates kernel branches at points where functionality is no longer
+shared and thus, needs to be isolated. For example, board-specific
+incompatibilities would require different functionality and would
+require a branch to separate the features. Likewise, for specific kernel
+features, the same branching strategy is used.
+
+This "tree-like" architecture results in a structure that has features
+organized to be specific for particular functionality, single kernel
+types, or a subset of kernel types. Thus, the user has the ability to
+see the added features and the commits that make up those features. In
+addition to being able to see added features, the user can also view the
+history of what made up the baseline Linux kernel.
+
+Another consequence of this strategy results in not having to store the
+same feature twice internally in the tree. Rather, the kernel team
+stores the unique differences required to apply the feature onto the
+kernel type in question.
+
+.. note::
+
+ The Yocto Project team strives to place features in the tree such
+ that features can be shared by all boards and kernel types where
+ possible. However, during development cycles or when large features
+ are merged, the team cannot always follow this practice. In those
+ cases, the team uses isolated branches to merge features.
+
+BSP-specific code additions are handled in a similar manner to
+kernel-specific additions. Some BSPs only make sense given certain
+kernel types. So, for these types, the team creates branches off the end
+of that kernel type for all of the BSPs that are supported on that
+kernel type. From the perspective of the tools that create the BSP
+branch, the BSP is really no different than a feature. Consequently, the
+same branching strategy applies to BSPs as it does to kernel features.
+So again, rather than store the BSP twice, the team only stores the
+unique differences for the BSP across the supported multiple kernels.
+
+While this strategy can result in a tree with a significant number of
+branches, it is important to realize that from the developer's point of
+view, there is a linear path that travels from the baseline
+``kernel.org``, through a select group of features and ends with their
+BSP-specific commits. In other words, the divisions of the kernel are
+transparent and are not relevant to the developer on a day-to-day basis.
+From the developer's perspective, this path is the "master" branch in
+Git terms. The developer does not need to be aware of the existence of
+any other branches at all. Of course, value exists in the having these
+branches in the tree, should a person decide to explore them. For
+example, a comparison between two BSPs at either the commit level or at
+the line-by-line code ``diff`` level is now a trivial operation.
+
+The following illustration shows the conceptual Yocto Linux kernel.
+
+.. image:: figures/kernel-architecture-overview.png
+ :align: center
+
+In the illustration, the "Kernel.org Branch Point" marks the specific
+spot (or Linux kernel release) from which the Yocto Linux kernel is
+created. From this point forward in the tree, features and differences
+are organized and tagged.
+
+The "Yocto Project Baseline Kernel" contains functionality that is
+common to every kernel type and BSP that is organized further along in
+the tree. Placing these common features in the tree this way means
+features do not have to be duplicated along individual branches of the
+tree structure.
+
+From the "Yocto Project Baseline Kernel", branch points represent
+specific functionality for individual Board Support Packages (BSPs) as
+well as real-time kernels. The illustration represents this through
+three BSP-specific branches and a real-time kernel branch. Each branch
+represents some unique functionality for the BSP or for a real-time
+Yocto Linux kernel.
+
+In this example structure, the "Real-time (rt) Kernel" branch has common
+features for all real-time Yocto Linux kernels and contains more
+branches for individual BSP-specific real-time kernels. The illustration
+shows three branches as an example. Each branch points the way to
+specific, unique features for a respective real-time kernel as they
+apply to a given BSP.
+
+The resulting tree structure presents a clear path of markers (or
+branches) to the developer that, for all practical purposes, is the
+Yocto Linux kernel needed for any given set of requirements.
+
+.. note::
+
+ Keep in mind the figure does not take into account all the supported
+ Yocto Linux kernels, but rather shows a single generic kernel just
+ for conceptual purposes. Also keep in mind that this structure
+ represents the Yocto Project
+ Source Repositories
+ that are either pulled from during the build or established on the
+ host development system prior to the build by either cloning a
+ particular kernel's Git repository or by downloading and unpacking a
+ tarball.
+
+Working with the kernel as a structured tree follows recognized
+community best practices. In particular, the kernel as shipped with the
+product, should be considered an "upstream source" and viewed as a
+series of historical and documented modifications (commits). These
+modifications represent the development and stabilization done by the
+Yocto Project kernel development team.
+
+Because commits only change at significant release points in the product
+life cycle, developers can work on a branch created from the last
+relevant commit in the shipped Yocto Project Linux kernel. As mentioned
+previously, the structure is transparent to the developer because the
+kernel tree is left in this state after cloning and building the kernel.
+
+Kernel Build File Hierarchy
+===========================
+
+Upstream storage of all the available kernel source code is one thing,
+while representing and using the code on your host development system is
+another. Conceptually, you can think of the kernel source repositories
+as all the source files necessary for all the supported Yocto Linux
+kernels. As a developer, you are just interested in the source files for
+the kernel on which you are working. And, furthermore, you need them
+available on your host system.
+
+Kernel source code is available on your host system several different
+ways:
+
+- *Files Accessed While using devtool:* ``devtool``, which is
+ available with the Yocto Project, is the preferred method by which to
+ modify the kernel. See the ":ref:`kernel-dev/kernel-dev-intro:kernel modification workflow`" section.
+
+- *Cloned Repository:* If you are working in the kernel all the time,
+ you probably would want to set up your own local Git repository of
+ the Yocto Linux kernel tree. For information on how to clone a Yocto
+ Linux kernel Git repository, see the
+ ":ref:`kernel-dev/kernel-dev-common:preparing the build host to work on the kernel`"
+ section.
+
+- *Temporary Source Files from a Build:* If you just need to make some
+ patches to the kernel using a traditional BitBake workflow (i.e. not
+ using the ``devtool``), you can access temporary kernel source files
+ that were extracted and used during a kernel build.
+
+The temporary kernel source files resulting from a build using BitBake
+have a particular hierarchy. When you build the kernel on your
+development system, all files needed for the build are taken from the
+source repositories pointed to by the
+:term:`SRC_URI` variable and gathered
+in a temporary work area where they are subsequently used to create the
+unique kernel. Thus, in a sense, the process constructs a local source
+tree specific to your kernel from which to generate the new kernel
+image.
+
+The following figure shows the temporary file structure created on your
+host system when you build the kernel using Bitbake. This
+:term:`Build Directory` contains all the
+source files used during the build.
+
+.. image:: figures/kernel-overview-2-generic.png
+ :align: center
+
+Again, for additional information on the Yocto Project kernel's
+architecture and its branching strategy, see the
+":ref:`kernel-dev/kernel-dev-concepts-appx:yocto linux kernel architecture and branching strategies`"
+section. You can also reference the
+":ref:`kernel-dev/kernel-dev-common:using \`\`devtool\`\` to patch the kernel`"
+and
+":ref:`kernel-dev/kernel-dev-common:using traditional kernel development to patch the kernel`"
+sections for detailed example that modifies the kernel.
+
+Determining Hardware and Non-Hardware Features for the Kernel Configuration Audit Phase
+=======================================================================================
+
+This section describes part of the kernel configuration audit phase that
+most developers can ignore. For general information on kernel
+configuration including ``menuconfig``, ``defconfig`` files, and
+configuration fragments, see the
+":ref:`kernel-dev/kernel-dev-common:configuring the kernel`" section.
+
+During this part of the audit phase, the contents of the final
+``.config`` file are compared against the fragments specified by the
+system. These fragments can be system fragments, distro fragments, or
+user-specified configuration elements. Regardless of their origin, the
+OpenEmbedded build system warns the user if a specific option is not
+included in the final kernel configuration.
+
+By default, in order to not overwhelm the user with configuration
+warnings, the system only reports missing "hardware" options as they
+could result in a boot failure or indicate that important hardware is
+not available.
+
+To determine whether or not a given option is "hardware" or
+"non-hardware", the kernel Metadata in ``yocto-kernel-cache`` contains
+files that classify individual or groups of options as either hardware
+or non-hardware. To better show this, consider a situation where the
+``yocto-kernel-cache`` contains the following files:
+::
+
+ yocto-kernel-cache/features/drm-psb/hardware.cfg
+ yocto-kernel-cache/features/kgdb/hardware.cfg
+ yocto-kernel-cache/ktypes/base/hardware.cfg
+ yocto-kernel-cache/bsp/mti-malta32/hardware.cfg
+ yocto-kernel-cache/bsp/qemu-ppc32/hardware.cfg
+ yocto-kernel-cache/bsp/qemuarma9/hardware.cfg
+ yocto-kernel-cache/bsp/mti-malta64/hardware.cfg
+ yocto-kernel-cache/bsp/arm-versatile-926ejs/hardware.cfg
+ yocto-kernel-cache/bsp/common-pc/hardware.cfg
+ yocto-kernel-cache/bsp/common-pc-64/hardware.cfg
+ yocto-kernel-cache/features/rfkill/non-hardware.cfg
+ yocto-kernel-cache/ktypes/base/non-hardware.cfg
+ yocto-kernel-cache/features/aufs/non-hardware.kcf
+ yocto-kernel-cache/features/ocf/non-hardware.kcf
+ yocto-kernel-cache/ktypes/base/non-hardware.kcf
+ yocto-kernel-cache/ktypes/base/hardware.kcf
+ yocto-kernel-cache/bsp/qemu-ppc32/hardware.kcf
+
+The following list
+provides explanations for the various files:
+
+- ``hardware.kcf``: Specifies a list of kernel Kconfig files that
+ contain hardware options only.
+
+- ``non-hardware.kcf``: Specifies a list of kernel Kconfig files that
+ contain non-hardware options only.
+
+- ``hardware.cfg``: Specifies a list of kernel ``CONFIG_`` options that
+ are hardware, regardless of whether or not they are within a Kconfig
+ file specified by a hardware or non-hardware Kconfig file (i.e.
+ ``hardware.kcf`` or ``non-hardware.kcf``).
+
+- ``non-hardware.cfg``: Specifies a list of kernel ``CONFIG_`` options
+ that are not hardware, regardless of whether or not they are within a
+ Kconfig file specified by a hardware or non-hardware Kconfig file
+ (i.e. ``hardware.kcf`` or ``non-hardware.kcf``).
+
+Here is a specific example using the
+``kernel-cache/bsp/mti-malta32/hardware.cfg``:
+::
+
+ CONFIG_SERIAL_8250
+ CONFIG_SERIAL_8250_CONSOLE
+ CONFIG_SERIAL_8250_NR_UARTS
+ CONFIG_SERIAL_8250_PCI
+ CONFIG_SERIAL_CORE
+ CONFIG_SERIAL_CORE_CONSOLE
+ CONFIG_VGA_ARB
+
+The kernel configuration audit automatically detects
+these files (hence the names must be exactly the ones discussed here),
+and uses them as inputs when generating warnings about the final
+``.config`` file.
+
+A user-specified kernel Metadata repository, or recipe space feature,
+can use these same files to classify options that are found within its
+``.cfg`` files as hardware or non-hardware, to prevent the OpenEmbedded
+build system from producing an error or warning when an option is not in
+the final ``.config`` file.