31 Jul, 2020
1 commit
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- Add support for a zstd compressed initramfs.
- Add compression for compressing built-in initramfs with zstd.
I have tested this patch by boot testing with buildroot and QEMU.
Specifically, I booted the kernel with both a zstd and gzip compressed
initramfs, both built into the kernel and separate. I ensured that the
correct compression algorithm was used. I tested on arm, aarch64, i386,
and x86_64.This patch has been tested in production on aarch64 and x86_64 devices.
Additionally, I have performance measurements from internal use in
production. On an aarch64 device we saw 19 second boot time improvement
from switching from lzma to zstd (27 seconds to 8 seconds). On an x86_64
device we saw a 9 second boot time reduction from switching from xz to
zstd.Signed-off-by: Nick Terrell
Signed-off-by: Ingo Molnar
Tested-by: Sedat Dilek
Reviewed-by: Kees Cook
Link: https://lore.kernel.org/r/20200730190841.2071656-5-nickrterrell@gmail.com
17 Mar, 2020
1 commit
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Even though INITRAMFS_SOURCE kconfig option isn't set in most of
defconfigs it is used (set) extensively by various build systems.
Commit f26661e12765 ("initramfs: make initramfs compression choice
non-optional") has changed default compression mode. Previously we
compress initramfs using available compression algorithm. Now
we don't use any compression at all by default.
It significantly increases the image size in case of build system
chooses embedded initramfs. Initially I faced with this issue while
using buildroot.As of today it's not possible to set preferred compression mode
in target defconfig as this option depends on INITRAMFS_SOURCE
being set. Modification of all build systems either doesn't look
like good option.Let's instead rewrite initramfs compression mode choices list
the way that "INITRAMFS_COMPRESSION_NONE" will be the last option
in the list. In that case it will be chosen only if all other
options (which implements any compression) are not available.Signed-off-by: Eugeniy Paltsev
Signed-off-by: Masahiro Yamada
04 Feb, 2020
1 commit
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Since commit ddd09bcc899f ("initramfs: make compression options not
depend on INITRAMFS_SOURCE"), Kconfig asks the compression mode for
the built-in initramfs regardless of INITRAMFS_SOURCE.It is technically simpler, but pointless from a UI perspective,
Linus says [1].When INITRAMFS_SOURCE is empty, usr/Makefile creates a tiny default
cpio, which is so small that nobody cares about the compression.This commit hides the Kconfig choice in that case. The default cpio
is embedded without compression, which was the original behavior.[1]: https://lkml.org/lkml/2020/2/1/160
Suggested-by: Linus Torvalds
Signed-off-by: Masahiro Yamada
Signed-off-by: Linus Torvalds
15 Jan, 2020
1 commit
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Currently, usr/gen_initramfs.sh takes care of all the use-cases:
[1] generates a cpio file unless CONFIG_INITRAMFS_SOURCE points to
a single cpio archive[2] If CONFIG_INITRAMFS_SOURCE is the path to a cpio archive,
use it as-is.[3] Compress the cpio file according to CONFIG_INITRAMFS_COMPRESSION_*
unless it is passed a compressed archive.To simplify the script, move [2] and [3] to usr/Makefile.
If CONFIG_INITRAMFS_SOURCE is the path to a cpio archive, there is
no need to run this shell script.For the cpio archive compression, you can re-use the rules from
scripts/Makefile.lib .Signed-off-by: Masahiro Yamada
14 Jan, 2020
3 commits
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Currently, the choice of the initramfs compression mode is too complex
because users are allowed to not specify the compression mode at all.I think it makes more sense to require users to choose the compression
mode explicitly, and delete the fallback defaults of INITRAMFS_COMPRESSION.Signed-off-by: Masahiro Yamada
-
Even if INITRAMFS_SOURCE is empty, usr/gen_initramfs.sh generates a
tiny default initramfs, which is embedded in vmlinux.So, defining INITRAMFS_COMPRESSION* options should be valid irrespective
of INITRAMFS_SOURCE.Signed-off-by: Masahiro Yamada
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init/Kconfig includes usr/Kconfig inside the "if BLK_DEV_INITRD" ...
"endif" block:if BLK_DEV_INITRD
source "usr/Kconfig"
endif
Hence, all the defines in usr/Kconfig depend on BLK_DEV_INITRD.
Remove the redundant "depends on BLK_DEV_INITRD".
Signed-off-by: Masahiro Yamada
Reviewed-by: Greg Thelen
15 Jul, 2019
2 commits
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Those documents describe a kAPI. So, add to the driver-api
book.Signed-off-by: Mauro Carvalho Chehab
-
The two files there describes a Kernel API feature, used to
support early userspace stuff. Prepare for moving them to
the kernel API book by converting to ReST format.The conversion itself was quite trivial: just add/mark a few
titles as such, add a literal block markup, add a table markup
and a few blank lines, in order to make Sphinx to properly parse it.At its new index.rst, let's add a :orphan: while this is not linked to
the main index.rst file, in order to avoid build warnings.Signed-off-by: Mauro Carvalho Chehab
02 Nov, 2017
1 commit
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Many source files in the tree are missing licensing information, which
makes it harder for compliance tools to determine the correct license.By default all files without license information are under the default
license of the kernel, which is GPL version 2.Update the files which contain no license information with the 'GPL-2.0'
SPDX license identifier. The SPDX identifier is a legally binding
shorthand, which can be used instead of the full boiler plate text.This patch is based on work done by Thomas Gleixner and Kate Stewart and
Philippe Ombredanne.How this work was done:
Patches were generated and checked against linux-4.14-rc6 for a subset of
the use cases:
- file had no licensing information it it.
- file was a */uapi/* one with no licensing information in it,
- file was a */uapi/* one with existing licensing information,Further patches will be generated in subsequent months to fix up cases
where non-standard license headers were used, and references to license
had to be inferred by heuristics based on keywords.The analysis to determine which SPDX License Identifier to be applied to
a file was done in a spreadsheet of side by side results from of the
output of two independent scanners (ScanCode & Windriver) producing SPDX
tag:value files created by Philippe Ombredanne. Philippe prepared the
base worksheet, and did an initial spot review of a few 1000 files.The 4.13 kernel was the starting point of the analysis with 60,537 files
assessed. Kate Stewart did a file by file comparison of the scanner
results in the spreadsheet to determine which SPDX license identifier(s)
to be applied to the file. She confirmed any determination that was not
immediately clear with lawyers working with the Linux Foundation.Criteria used to select files for SPDX license identifier tagging was:
- Files considered eligible had to be source code files.
- Make and config files were included as candidates if they contained >5
lines of source
- File already had some variant of a license header in it (even if
Reviewed-by: Philippe Ombredanne
Reviewed-by: Thomas Gleixner
Signed-off-by: Greg Kroah-Hartman
07 Jul, 2017
2 commits
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Clarify help text that compression applies to ramfs as well as legacy ramdisk.
Link: http://lkml.kernel.org/r/f206a960-5a61-cf59-f27c-e9f34872063c@landley.net
Signed-off-by: Rob Landley
Cc: Jonathan Corbet
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
…hat -1 means "current user".
Teach INITRAMFS_ROOT_UID and INITRAMFS_ROOT_GID that -1 means "current user".
Link: http://lkml.kernel.org/r/2df3a9fb-4378-fa16-679d-99e788926c05@landley.net
Signed-off-by: Rob Landley <rob@landley.net>
Cc: Michal Marek <mmarek@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
03 Jun, 2017
1 commit
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Commit db2aa7fd15e8 ("initramfs: allow again choice of the embedded
initram compression algorithm") introduced the possibility to select the
initramfs compression algorithm from Kconfig and while this is a nice
feature it broke the use case described below.Here is what my build system does:
- kernel is initially configured not to have an initramfs included
- build the user space root file system
- re-configure the kernel to have an initramfs included
(CONFIG_INITRAMFS_SOURCE="/path/to/romfs") and set relevant
CONFIG_INITRAMFS options, in my case, no compression option
(CONFIG_INITRAMFS_COMPRESSION_NONE)- kernel is re-built with these options -> kernel+initramfs image is
copied- kernel is re-built again without these options -> kernel image is
copiedBuilding a kernel without an initramfs means setting this option:
CONFIG_INITRAMFS_SOURCE="" (and this one only)
whereas building a kernel with an initramfs means setting these options:
CONFIG_INITRAMFS_SOURCE="/home/fainelli/work/uclinux-rootfs/romfs /home/fainelli/work/uclinux-rootfs/misc/initramfs.dev"
CONFIG_INITRAMFS_ROOT_UID=1000
CONFIG_INITRAMFS_ROOT_GID=1000
CONFIG_INITRAMFS_COMPRESSION_NONE=y
CONFIG_INITRAMFS_COMPRESSION=""Commit db2aa7fd15e85 ("initramfs: allow again choice of the embedded
initram compression algorithm") is problematic because
CONFIG_INITRAMFS_COMPRESSION which is used to determine the
initramfs_data.cpio extension/compression is a string, and due to how
Kconfig works it will evaluate in order, how to assign it.Setting CONFIG_INITRAMFS_COMPRESSION_NONE with CONFIG_INITRAMFS_SOURCE=""
cannot possibly work (because of the depends on INITRAMFS_SOURCE!=""
imposed on CONFIG_INITRAMFS_COMPRESSION ) yet we still get
CONFIG_INITRAMFS_COMPRESSION assigned to ".gz" because CONFIG_RD_GZIP=y
is set in my kernel, even when there is no initramfs being built.So we basically end-up generating two initramfs_data.cpio* files, one
without extension, and one with .gz. This causes usr/Makefile to track
usr/initramfs_data.cpio.gz, and not usr/initramfs_data.cpio anymore,
that is also largely problematic after 9e3596b0c6539e ("kbuild:
initramfs cleanup, set target from Kconfig") because we used to track
all possible initramfs_data files in the $(targets) variable before that
commit.The end result is that the kernel with an initramfs clearly does not
contain what we expect it to, it has a stale initramfs_data.cpio file
built into it, and we keep re-generating an initramfs_data.cpio.gz file
which is not the one that we want to include in the kernel image proper.The fix consists in hiding CONFIG_INITRAMFS_COMPRESSION when
CONFIG_INITRAMFS_SOURCE="". This puts us back in a state to the
pre-4.10 behavior where we can properly disable and re-enable initramfs
within the same kernel .config file, and be in control of what
CONFIG_INITRAMFS_COMPRESSION is set to.Fixes: db2aa7fd15e8 ("initramfs: allow again choice of the embedded initram compression algorithm")
Fixes: 9e3596b0c653 ("kbuild: initramfs cleanup, set target from Kconfig")
Link: http://lkml.kernel.org/r/20170521033337.6197-1-f.fainelli@gmail.com
Signed-off-by: Florian Fainelli
Acked-by: Nicholas Piggin
Cc: P J P
Cc: Paul Bolle
Cc: Michal Marek
Cc: Daniel Thompson
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
09 May, 2017
1 commit
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Many "embedded" architectures provide CMDLINE_FORCE to allow the kernel
to override the command line provided by an inflexible bootloader.
However there is currrently no way for the kernel to override the
initramfs image provided by the bootloader meaning there are still ways
for bootloaders to make things difficult for us.Fix this by introducing INITRAMFS_FORCE which can prevent the kernel
from loading the bootloader supplied image.We use CMDLINE_FORCE (and its friend CMDLINE_EXTEND) to imply that the
system has an inflexible bootloader. This allow us to avoid presenting
this config option to users of systems where inflexible bootloaders
aren't usually a problem.Link: http://lkml.kernel.org/r/20170217121940.30126-1-daniel.thompson@linaro.org
Signed-off-by: Daniel Thompson
Cc: Al Viro
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
15 Dec, 2016
2 commits
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Choosing the appropriate compression option when using an embedded
initramfs can result in significant size differences in the resulting
data.This is caused by avoiding double compression of the initramfs contents.
For example on my tests, choosing CONFIG_INITRAMFS_COMPRESSION_NONE when
compressing the kernel using XZ) results in up to 500KiB differences
(9MiB to 8.5MiB) in the kernel size as the dictionary will not get
polluted with uncomprensible data and may reuse kernel data too.Despite embedding an uncompressed initramfs, a user may want to allow
for a compressed extra initramfs to be passed using the rd system, for
example to boot a recovery system. 9ba4bcb645898d ("initramfs: read
CONFIG_RD_ variables for initramfs compression") broke that behavior by
making the choice based on CONFIG_RD_* instead of adding
CONFIG_INITRAMFS_COMPRESSION_LZ4. Saddly, CONFIG_RD_* is also used to
choose the supported RD compression algorithms by the kernel and a user
may want to support more than one.This patch also reverts commit 3e4e0f0a875 ("initramfs: remove
"compression mode" choice") restoring back the "compression mode" choice
and includes the CONFIG_INITRAMFS_COMPRESSION_LZ4 option which was never
added.As a result the following options are added or readed affecting the embedded
initramfs compression:
INITRAMFS_COMPRESSION_NONE Do no compression
INITRAMFS_COMPRESSION_GZIP Compress using gzip
INITRAMFS_COMPRESSION_BZIP2 Compress using bzip2
INITRAMFS_COMPRESSION_LZMA Compress using lzma
INITRAMFS_COMPRESSION_XZ Compress using xz
INITRAMFS_COMPRESSION_LZO Compress using lzo
INITRAMFS_COMPRESSION_LZ4 Compress using lz4These depend on the corresponding CONFIG_RD_* option being set (except
NONE which has no dependencies).This patch depends on the previous one (the previous version didn't) to
simplify the way in which the algorithm is chosen and keep backwards
compatibility with the behaviour introduced by 9ba4bcb645898
("initramfs: read CONFIG_RD_ variables for initramfs compression").Link: http://lkml.kernel.org/r/57EAD77B.7090607@klondike.es
Signed-off-by: Francisco Blas Izquierdo Riera (klondike)
Cc: P J P
Cc: Paul Bolle
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Move the current builtin initram compression algorithm selection from
the Makefile into the INITRAMFS_COMPRESSION variable. This makes
deciding algorithm precedence easier and would allow for overrides if
new algorithms want to be tested.Link: http://lkml.kernel.org/r/57EAD769.1090401@klondike.es
Signed-off-by: Francisco Blas Izquierdo Riera (klondike)
Cc: P J P
Cc: Paul Bolle
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
14 Dec, 2014
1 commit
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The kernel has support for (nearly) every compression algorithm known to
man, each to handle some particular microscopic niche.Unfortunately all of these always get compiled in if you want to support
INITRDs, and can be only disabled when CONFIG_EXPERT is set.I don't see why I need to set EXPERT just to properly configure the initrd
compression algorithms, and not always include every possible algorithmUsually the initrd is just compressed with gzip anyways, at least that's
true on all distributions I use.Remove the dependencies for initrd compression on CONFIG_EXPERT.
Make the various options just default y, which should be good enough to
not break any previous configuration.Signed-off-by: Andi Kleen
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
07 Jun, 2014
1 commit
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Commit 9ba4bcb64589 ("initramfs: read CONFIG_RD_ variables for initramfs
compression") removed the users of the various INITRAMFS_COMPRESSION_*
Kconfig symbols. So since v3.13 the entire "Built-in initramfs
compression mode" choice is a set of knobs connected to nothing. The
entire choice can safely be removed.Signed-off-by: Paul Bolle
Cc: P J P
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
10 Jul, 2013
1 commit
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Add support for extracting LZ4-compressed kernel images, as well as
LZ4-compressed ramdisk images in the kernel boot process.Signed-off-by: Kyungsik Lee
Cc: "H. Peter Anvin"
Cc: Ingo Molnar
Cc: Thomas Gleixner
Cc: Russell King
Cc: Borislav Petkov
Cc: Florian Fainelli
Cc: Yann Collet
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
01 Jun, 2012
1 commit
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There have been new compression algorithms added without updating nearby
relevant descriptive text that refers to (a) the number of compression
algorithms and (b) the most recent one. Fix these inconsistencies.Signed-off-by: Randy Dunlap
Reported-by:
Cc: Lasse Collin
Cc: "H. Peter Anvin"
Cc: Markus Trippelsdorf
Cc: Alain Knaff
Cc: Albin Tonnerre
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
21 Jan, 2011
1 commit
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The meaning of CONFIG_EMBEDDED has long since been obsoleted; the option
is used to configure any non-standard kernel with a much larger scope than
only small devices.This patch renames the option to CONFIG_EXPERT in init/Kconfig and fixes
references to the option throughout the kernel. A new CONFIG_EMBEDDED
option is added that automatically selects CONFIG_EXPERT when enabled and
can be used in the future to isolate options that should only be
considered for embedded systems (RISC architectures, SLOB, etc).Calling the option "EXPERT" more accurately represents its intention: only
expert users who understand the impact of the configuration changes they
are making should enable it.Reviewed-by: Ingo Molnar
Acked-by: David Woodhouse
Signed-off-by: David Rientjes
Cc: Greg KH
Cc: "David S. Miller"
Cc: Jens Axboe
Cc: Arnd Bergmann
Cc: Robin Holt
Cc:
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
14 Jan, 2011
1 commit
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This implements the API defined in which is
used for kernel, initramfs, and initrd decompression. This patch together
with the first patch is enough for XZ-compressed initramfs and initrd;
XZ-compressed kernel will need arch-specific changes.The buffering requirements described in decompress_unxz.c are stricter
than with gzip, so the relevant changes should be done to the
arch-specific code when adding support for XZ-compressed kernel.
Similarly, the heap size in arch-specific pre-boot code may need to be
increased (30 KiB is enough).The XZ decompressor needs memmove(), memeq() (memcmp() == 0), and
memzero() (memset(ptr, 0, size)), which aren't available in all
arch-specific pre-boot environments. I'm including simple versions in
decompress_unxz.c, but a cleaner solution would naturally be nicer.Signed-off-by: Lasse Collin
Cc: "H. Peter Anvin"
Cc: Alain Knaff
Cc: Albin Tonnerre
Cc: Phillip Lougher
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
23 Aug, 2010
1 commit
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Deleted a word which apeared twice.
Signed-off-by: Stephan Sperber
Signed-off-by: Jiri Kosina
12 Jan, 2010
1 commit
-
Signed-off-by: Albin Tonnerre
Tested-by: Wu Zhangjin
Acked-by: "H. Peter Anvin"
Cc: Ingo Molnar
Cc: Thomas Gleixner
Tested-by: Russell King
Acked-by: Russell King
Cc: Ralf Baechle
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
01 Apr, 2009
1 commit
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Impact: quiet Kconfig warning
It appears that Kconfig simply has no way to provide defaults for
entries that exist inside a conditionalized choice block.
Fortunately, it turns out we don't actually ever use
CONFIG_INITRAMFS_COMPRESSION_NONE, so we can just drop it for
everything outside the choice block.Signed-off-by: H. Peter Anvin
29 Mar, 2009
4 commits
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Impact: Kconfig noise reduction, documentation
The default initramfs is so small that it makes no sense to worry
about the additional memory taken by not double-compressing it.
Therefore, don't bug the user with it.Also, improve the description of the option, which was downright
incorrect.Signed-off-by: H. Peter Anvin
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Impact: message formatting
Consistently spell LZMA in all capitals, since it (unlike gzip or
bzip2) is an acronym.Signed-off-by: H. Peter Anvin
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Impact: Kconfig clarification
Make it clear that the CONFIG_RD_* options are about what formats are
supported, not about what formats are actually being used.Signed-off-by: H. Peter Anvin
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Impact: reduce Kconfig noise
Move the options that control possible initramfs/initrd compressions
underneath CONFIG_EMBEDDED. The only impact of leaving these options
set to y is additional code in the init section of the kernel; there
is no reason to burden non-embedded users with these options.Signed-off-by: H. Peter Anvin
20 Feb, 2009
1 commit
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Impact: Avoids silent environment dependency
Make builtin initramfs compression an explicit configurable. The
previous version would pick a compression based on the binaries which
were installed on the system, which could lead to unexpected results.
It is now explicitly configured, and not having the appropriate
binaries installed on the build host is simply an error.Signed-off-by: Alain Knaff
Signed-off-by: H. Peter Anvin
07 Jan, 2009
1 commit
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Impact: Partial resolution of build failure
Move the initrd/initramfs configuration options from
drivers/block/Kconfig to usr/Kconfig, since they do not and should not
depend on CONFIG_BLK_DEV. This fixes builds when CONFIG_BLK_DEV=n.Signed-off-by: H. Peter Anvin
03 May, 2007
1 commit
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Signed-off-by: Alexander E. Patrakov
Signed-off-by: Sam Ravnborg
11 Aug, 2005
1 commit
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Move initramfs options from Device Drivers | Block Drivers to General Setup
This is a more natural place for this option.Furthermore separate out intramfs options to usr/Kconfig
Signed-off-by: Sam Ravnborg