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2019-07-20Merge tag 'kbuild-v5.3-2' of ↵Linus Torvalds1-8/+0
git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild Pull more Kbuild updates from Masahiro Yamada: - match the directory structure of the linux-libc-dev package to that of Debian-based distributions - fix incorrect include/config/auto.conf generation when Kconfig creates it along with the .config file - remove misleading $(AS) from documents - clean up precious tag files by distclean instead of mrproper - add a new coccinelle patch for devm_platform_ioremap_resource migration - refactor module-related scripts to read modules.order instead of $(MODVERDIR)/*.mod files to get the list of created modules - remove MODVERDIR - update list of header compile-test - add -fcf-protection=none flag to avoid conflict with the retpoline flags when CONFIG_RETPOLINE=y - misc cleanups * tag 'kbuild-v5.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: (25 commits) kbuild: add -fcf-protection=none when using retpoline flags kbuild: update compile-test header list for v5.3-rc1 kbuild: split out *.mod out of {single,multi}-used-m rules kbuild: remove 'prepare1' target kbuild: remove the first line of *.mod files kbuild: create *.mod with full directory path and remove MODVERDIR kbuild: export_report: read modules.order instead of .tmp_versions/*.mod kbuild: modpost: read modules.order instead of $(MODVERDIR)/*.mod kbuild: modsign: read modules.order instead of $(MODVERDIR)/*.mod kbuild: modinst: read modules.order instead of $(MODVERDIR)/*.mod scsi: remove pointless $(MODVERDIR)/$(obj)/53c700.ver kbuild: remove duplication from modules.order in sub-directories kbuild: get rid of kernel/ prefix from in-tree modules.{order,builtin} kbuild: do not create empty modules.order in the prepare stage coccinelle: api: add devm_platform_ioremap_resource script kbuild: compile-test headers listed in header-test-m as well kbuild: remove unused hostcc-option kbuild: remove tag files by distclean instead of mrproper kbuild: add --hash-style= and --build-id unconditionally kbuild: get rid of misleading $(AS) from documents ...
2019-07-20kbuild: update compile-test header list for v5.3-rc1Masahiro Yamada1-8/+0
- Some headers graduated from the blacklist - hyperv_timer.h joined the header-test when CONFIG_X86=y - nf_tables*.h joined the header-test when CONFIG_NF_TABLES is enabled. - The entry for nf_tables_offload.h was added to fix build error for the combination of CONFIG_NF_TABLES=n and CONFIG_KERNEL_HEADER_TEST=y. - The entry for iomap.h was added because this header is supposed to be included only when CONFIG_BLOCK=y Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2019-07-15docs: early-userspace: move to driver-api guideMauro Carvalho Chehab1-1/+1
Those documents describe a kAPI. So, add to the driver-api book. Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
2019-07-15docs: early-userspace: convert docs to ReST and rename to *.rstMauro Carvalho Chehab1-1/+1
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 <mchehab+samsung@kernel.org>
2019-07-08kbuild: compile-test exported headers to ensure they are self-containedMasahiro Yamada4-1/+137
Multiple people have suggested compile-testing UAPI headers to ensure they can be really included from user-space. "make headers_check" is obviously not enough to catch bugs, and we often leak unresolved references to user-space. Use the new header-test-y syntax to implement it. Please note exported headers are compile-tested with a completely different set of compiler flags. The header search path is set to $(objtree)/usr/include since exported headers should not include unexported ones. We use -std=gnu89 for the kernel space since the kernel code highly depends on GNU extensions. On the other hand, UAPI headers should be written in more standardized C, so they are compiled with -std=c90. This will emit errors if C++ style comments, the keyword 'inline', etc. are used. Please use C style comments (/* ... */), '__inline__', etc. in UAPI headers. There is additional compiler requirement to enable this test because many of UAPI headers include <stdlib.h>, <sys/ioctl.h>, <sys/time.h>, etc. directly or indirectly. You cannot use kernel.org pre-built toolchains [1] since they lack <stdlib.h>. I reused CONFIG_CC_CAN_LINK to check the system header availability. The intention is slightly different, but a compiler that can link userspace programs provide system headers. For now, a lot of headers need to be excluded because they cannot be compiled standalone, but this is a good start point. [1] https://mirrors.edge.kernel.org/pub/tools/crosstool/index.html Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> Reviewed-by: Sam Ravnborg <sam@ravnborg.org>
2018-12-11user/Makefile: Fix typo and capitalization in comment sectionEugen Cazacu1-2/+2
Signed-off-by: Eugen Cazacu <green182day@hotmail.com> Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2018-08-22initramfs: move gen_initramfs_list.sh from scripts/ to usr/Masahiro Yamada2-1/+329
scripts/gen_initramfs_list.sh is only invoked from usr/Makefile. Move it so that all tools to create initramfs are self-contained in the usr/ directory. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2018-08-22export.h: remove VMLINUX_SYMBOL() and VMLINUX_SYMBOL_STR()Masahiro Yamada1-2/+2
With the special case handling for Blackfin and Metag was removed by commit 94e58e0ac312 ("export.h: remove code for prefixing symbols with underscore"), VMLINUX_SYMBOL() is no-op. Replace the remaining usages, then remove the definition of VMLINUX_SYMBOL() and VMLINUX_SYMBOL_STR(). Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2018-03-26kbuild: rename built-in.o to built-in.aNicholas Piggin1-1/+1
Incremental linking is gone, so rename built-in.o to built-in.a, which is the usual extension for archive files. This patch does two things, first is a simple search/replace: git grep -l 'built-in\.o' | xargs sed -i 's/built-in\.o/built-in\.a/g' The second is to invert nesting of nested text manipulations to avoid filtering built-in.a out from libs-y2: -libs-y2 := $(filter-out %.a, $(patsubst %/, %/built-in.a, $(libs-y))) +libs-y2 := $(patsubst %/, %/built-in.a, $(filter-out %.a, $(libs-y))) Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2017-11-03initramfs: fix initramfs rebuilds w/ compression after disablingFlorian Fainelli1-4/+5
This is a follow-up to commit 57ddfdaa9a72 ("initramfs: fix disabling of initramfs (and its compression)"). This particular commit fixed the use case where we build the kernel with an initramfs with no compression, and then we build the kernel with no initramfs. Now this still left us with the same case as described here: http://lkml.kernel.org/r/20170521033337.6197-1-f.fainelli@gmail.com not working with initramfs compression. This can be seen by the following steps/timestamps: https://www.spinics.net/lists/kernel/msg2598153.html .initramfs_data.cpio.gz.cmd is correct: cmd_usr/initramfs_data.cpio.gz := /bin/bash ./scripts/gen_initramfs_list.sh -o usr/initramfs_data.cpio.gz -u 1000 -g 1000 /home/fainelli/work/uclinux-rootfs/romfs /home/fainelli/work/uclinux-rootfs/misc/initramfs.dev and was generated the first time we did generate the gzip initramfs, so the command has not changed, nor its arguments, so we just don't call it, no initramfs cpio is re-generated as a consequence. The fix for this problem is just to properly keep track of the .initramfs_cpio_data.d file by suffixing it with the compression extension. This takes care of properly tracking dependencies such that the initramfs get (re)generated any time files are added/deleted etc. Link: http://lkml.kernel.org/r/20170930033936.6722-1-f.fainelli@gmail.com Fixes: db2aa7fd15e8 ("initramfs: allow again choice of the embedded initramfs compression algorithm") Fixes: 9e3596b0c653 ("kbuild: initramfs cleanup, set target from Kconfig") Signed-off-by: Florian Fainelli <f.fainelli@gmail.com> Cc: "Francisco Blas Izquierdo Riera (klondike)" <klondike@xiscosoft.net> Cc: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-11-02License cleanup: add SPDX GPL-2.0 license identifier to files with no licenseGreg Kroah-Hartman4-0/+4
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 <5 lines). All documentation files were explicitly excluded. The following heuristics were used to determine which SPDX license identifiers to apply. - when both scanners couldn't find any license traces, file was considered to have no license information in it, and the top level COPYING file license applied. For non */uapi/* files that summary was: SPDX license identifier # files ---------------------------------------------------|------- GPL-2.0 11139 and resulted in the first patch in this series. If that file was a */uapi/* path one, it was "GPL-2.0 WITH Linux-syscall-note" otherwise it was "GPL-2.0". Results of that was: SPDX license identifier # files ---------------------------------------------------|------- GPL-2.0 WITH Linux-syscall-note 930 and resulted in the second patch in this series. - if a file had some form of licensing information in it, and was one of the */uapi/* ones, it was denoted with the Linux-syscall-note if any GPL family license was found in the file or had no licensing in it (per prior point). Results summary: SPDX license identifier # files ---------------------------------------------------|------ GPL-2.0 WITH Linux-syscall-note 270 GPL-2.0+ WITH Linux-syscall-note 169 ((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause) 21 ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause) 17 LGPL-2.1+ WITH Linux-syscall-note 15 GPL-1.0+ WITH Linux-syscall-note 14 ((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause) 5 LGPL-2.0+ WITH Linux-syscall-note 4 LGPL-2.1 WITH Linux-syscall-note 3 ((GPL-2.0 WITH Linux-syscall-note) OR MIT) 3 ((GPL-2.0 WITH Linux-syscall-note) AND MIT) 1 and that resulted in the third patch in this series. - when the two scanners agreed on the detected license(s), that became the concluded license(s). - when there was disagreement between the two scanners (one detected a license but the other didn't, or they both detected different licenses) a manual inspection of the file occurred. - In most cases a manual inspection of the information in the file resulted in a clear resolution of the license that should apply (and which scanner probably needed to revisit its heuristics). - When it was not immediately clear, the license identifier was confirmed with lawyers working with the Linux Foundation. - If there was any question as to the appropriate license identifier, the file was flagged for further research and to be revisited later in time. In total, over 70 hours of logged manual review was done on the spreadsheet to determine the SPDX license identifiers to apply to the source files by Kate, Philippe, Thomas and, in some cases, confirmation by lawyers working with the Linux Foundation. Kate also obtained a third independent scan of the 4.13 code base from FOSSology, and compared selected files where the other two scanners disagreed against that SPDX file, to see if there was new insights. The Windriver scanner is based on an older version of FOSSology in part, so they are related. Thomas did random spot checks in about 500 files from the spreadsheets for the uapi headers and agreed with SPDX license identifier in the files he inspected. For the non-uapi files Thomas did random spot checks in about 15000 files. In initial set of patches against 4.14-rc6, 3 files were found to have copy/paste license identifier errors, and have been fixed to reflect the correct identifier. Additionally Philippe spent 10 hours this week doing a detailed manual inspection and review of the 12,461 patched files from the initial patch version early this week with: - a full scancode scan run, collecting the matched texts, detected license ids and scores - reviewing anything where there was a license detected (about 500+ files) to ensure that the applied SPDX license was correct - reviewing anything where there was no detection but the patch license was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied SPDX license was correct This produced a worksheet with 20 files needing minor correction. This worksheet was then exported into 3 different .csv files for the different types of files to be modified. These .csv files were then reviewed by Greg. Thomas wrote a script to parse the csv files and add the proper SPDX tag to the file, in the format that the file expected. This script was further refined by Greg based on the output to detect more types of files automatically and to distinguish between header and source .c files (which need different comment types.) Finally Greg ran the script using the .csv files to generate the patches. Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org> Reviewed-by: Philippe Ombredanne <pombredanne@nexb.com> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-07-06ramfs: clarify help text that compression applies to ramfs as well as legacy ↵Rob Landley1-6/+6
ramdisk. 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 <rob@landley.net> Cc: Jonathan Corbet <corbet@lwn.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-07-06scripts/gen_initramfs_list.sh: teach INITRAMFS_ROOT_UID and ↵Rob Landley1-8/+4
INITRAMFS_ROOT_GID that -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>
2017-06-02initramfs: fix disabling of initramfs (and its compression)Florian Fainelli1-0/+1
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 copied Building 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 <f.fainelli@gmail.com> Acked-by: Nicholas Piggin <npiggin@gmail.com> Cc: P J P <ppandit@redhat.com> Cc: Paul Bolle <pebolle@tiscali.nl> Cc: Michal Marek <mmarek@suse.cz> Cc: Daniel Thompson <daniel.thompson@linaro.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-05-08initramfs: provide a way to ignore image provided by bootloaderDaniel Thompson1-0/+10
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 <daniel.thompson@linaro.org> Cc: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-01-05kbuild: initramfs cleanup, set target from KconfigNicholas Piggin1-7/+7
Rather than keep a list of all possible compression types in the Makefile, set the target explicitly from Kconfig. Reviewed-by: Francisco Blas Izquierdo Riera (klondike) <klondike@klondike.es> Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-01-05kbuild: initramfs fix dependency checking for compressed targetNicholas Piggin1-1/+1
When using initramfs compression, the data file compression suffix gets quotes pulled in from Kconfig, e.g., initramfs_data.cpio".gz" which make does not match a target and causes rebuild. Fix this by filtering out quotes from the Kconfig string. Fixes: 35e669e1a254 ("initramfs: select builtin initram compression algorithm on KConfig instead of Makefile") Reviewed-by: Francisco Blas Izquierdo Riera (klondike) <klondike@klondike.es> Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-12-14initramfs: allow again choice of the embedded initram compression algorithmFrancisco Blas Izquierdo Riera (klondike)1-0/+117
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 lz4 These 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) <klondike@klondike.es> Cc: P J P <ppandit@redhat.com> Cc: Paul Bolle <pebolle@tiscali.nl> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-12-14initramfs: select builtin initram compression algorithm on KConfig instead ↵Francisco Blas Izquierdo Riera (klondike)2-19/+11
of Makefile 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) <klondike@klondike.es> Cc: P J P <ppandit@redhat.com> Cc: Paul Bolle <pebolle@tiscali.nl> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-12-13usr/Kconfig: make initrd compression algorithm selection not expertAndi Kleen1-12/+12
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 algorithm Usually 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 <ak@linux.intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-06-06initramfs: remove "compression mode" choicePaul Bolle1-77/+0
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 <pebolle@tiscali.nl> Cc: P J P <ppandit@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-11-13initramfs: read CONFIG_RD_ variables for initramfs compressionP J P1-9/+14
When expert configuration option(CONFIG_EXPERT) is enabled, menuconfig offers a choice of compression algorithm to compress initial ramfs image; This choice is stored into CONFIG_RD_* variables. But usr/Makefile uses earlier INITRAMFS_COMPRESSION_* macros to build initial ramfs file. Since none of them is defined, resulting 'initramfs_data.cpio' file remains un-compressed. This patch updates the Makefile to use CONFIG_RD_* variables and adds support for LZ4 compression algorithm. Also updates the 'gen_initramfs_list.sh' script to check whether a selected compression command is accessible or not. And fall-back to default gzip(1) compression when it is not. Signed-off-by: P J P <prasad@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-11-13gen_init_cpio: avoid NULL pointer dereference and rework env expandingMichal Nazarewicz1-18/+9
getenv() may return NULL if given environment variable does not exist which leads to NULL dereference when calling strncat. Besides that, the environment variable name was copied to a temporary env_var buffer, but this copying can be avoided by simply using the input string. Lastly, the whole loop can be greatly simplified by using the snprintf function instead of the playing with strncat. By the way, the current implementation allows a recursive variable expansion, as in: $ echo 'out ${A} out ' | A='a ${B} a' B=b /tmp/a out a b a out I'm assuming this is just a side effect and not a conscious decision (especially as this may lead to infinite loop), but I didn't want to change this behaviour without consulting. If the current behaviour is deamed incorrect, I'll be happy to send a patch without recursive processing. Signed-off-by: Michal Nazarewicz <mina86@mina86.com> Cc: Kees Cook <keescook@chromium.org> Cc: Jiri Kosina <jkosina@suse.cz> Cc: Jesper Juhl <jj@codesealer.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-07-09lib: add support for LZ4-compressed kernelKyungsik Lee1-0/+9
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 <kyungsik.lee@lge.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Russell King <rmk@arm.linux.org.uk> Cc: Borislav Petkov <bp@alien8.de> Cc: Florian Fainelli <florian@openwrt.org> Cc: Yann Collet <yann.collet.73@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-11-19gen_init_cpio: remove redundant empty lineJesper Juhl1-1/+0
Just a completely trivial patch to remove a completely redundant blank line from usr/gen_init_cpio.c Signed-off-by: Jesper Juhl <jj@codesealer.com> Signed-off-by: Jiri Kosina <jkosina@suse.cz>
2012-10-25gen_init_cpio: avoid stack overflow when expandingKees Cook1-20/+23
Fix possible overflow of the buffer used for expanding environment variables when building file list. In the extremely unlikely case of an attacker having control over the environment variables visible to gen_init_cpio, control over the contents of the file gen_init_cpio parses, and gen_init_cpio was built without compiler hardening, the attacker can gain arbitrary execution control via a stack buffer overflow. $ cat usr/crash.list file foo ${BIG}${BIG}${BIG}${BIG}${BIG}${BIG} 0755 0 0 $ BIG=$(perl -e 'print "A" x 4096;') ./usr/gen_init_cpio usr/crash.list *** buffer overflow detected ***: ./usr/gen_init_cpio terminated This also replaces the space-indenting with tabs. Patch based on existing fix extracted from grsecurity. Signed-off-by: Kees Cook <keescook@chromium.org> Cc: Michal Marek <mmarek@suse.cz> Cc: Brad Spengler <spender@grsecurity.net> Cc: PaX Team <pageexec@freemail.hu> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-05-31kconfig: update compression algorithm infoRandy Dunlap1-5/+5
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 <rdunlap@xenotime.net> Reported-by: <qasdfgtyuiop@gmail.com> Cc: Lasse Collin <lasse.collin@tukaani.org> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Markus Trippelsdorf <markus@trippelsdorf.de> Cc: Alain Knaff <alain@knaff.lu> Cc: Albin Tonnerre <albin.tonnerre@free-electrons.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-04-18initramfs: Use KBUILD_BUILD_TIMESTAMP for generated entriesMichal Marek1-13/+40
gen_init_cpio gets the current time and uses it for each symlink, special file, and directory. Grab the current time once and make it possible to override it with the KBUILD_BUILD_TIMESTAMP variable for reproducible builds. Signed-off-by: Michal Marek <mmarek@suse.cz>
2011-01-20kconfig: rename CONFIG_EMBEDDED to CONFIG_EXPERTDavid Rientjes1-9/+9
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 <mingo@elte.hu> Acked-by: David Woodhouse <david.woodhouse@intel.com> Signed-off-by: David Rientjes <rientjes@google.com> Cc: Greg KH <gregkh@suse.de> Cc: "David S. Miller" <davem@davemloft.net> Cc: Jens Axboe <axboe@kernel.dk> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Robin Holt <holt@sgi.com> Cc: <linux-arch@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-01-13decompressors: add boot-time XZ supportLasse Collin2-1/+22
This implements the API defined in <linux/decompress/generic.h> 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 <lasse.collin@tukaani.org> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Alain Knaff <alain@knaff.lu> Cc: Albin Tonnerre <albin.tonnerre@free-electrons.com> Cc: Phillip Lougher <phillip@lougher.demon.co.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-01-10Merge branch 'kbuild' of ↵Linus Torvalds1-6/+14
git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild-2.6 * 'kbuild' of git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild-2.6: mkuboot.sh: Fail if mkimage is missing gen_init_cpio: checkpatch fixes gen_init_cpio: Avoid race between call to stat() and call to open() modpost: Fix address calculation in reloc_location() Make fixdep error handling more explicit checksyscalls: Fix stand-alone usage modpost: Put .zdebug* section on white list kbuild: fix interaction of CONFIG_IKCONFIG and KCONFIG_CONFIG kbuild: export linux/{a.out,kvm,kvm_para}.h on headers_install_all kbuild: introduce HDR_ARCH_LIST for headers_install_all headers_install: check exit status of unifdef gen_init_cpio: remove leading `/' from file names scripts/genksyms: fix header usage fixdep: use hash table instead of a single array
2011-01-05gen_init_cpio: checkpatch fixesAndrew Morton1-2/+2
Cc: Jesper Juhl <jj@chaosbits.net> Cc: Michal Marek <mmarek@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Michal Marek <mmarek@suse.cz>
2010-12-29gen_init_cpio: Avoid race between call to stat() and call to open()Jesper Juhl1-6/+6
In usr/gen_init_cpio.c::cpio_mkfile() a call to stat() is made based on pathname, subsequently the file is open()'ed and then the value of the initial stat() call is used to allocate a buffer. This is not safe since the file may change between the call to stat() and the call to open(). Safer to just open() the file and then do fstat() using the filedescriptor returned by open. Signed-off-by: Jesper Juhl <jj@chaosbits.net> Acked-by: Jeff Garzik <jgarzik@redhat.com> Signed-off-by: Michal Marek <mmarek@suse.cz>
2010-12-14Merge commit 'v2.6.37-rc1' into kbuild/kbuildMichal Marek2-4/+4
2010-12-02gen_init_cpio: remove leading `/' from file namesThomas Chou1-0/+8
When we extracted the generated cpio archive using "cpio -id" command, it complained, cpio: Removing leading `/' from member names var/run cpio: Removing leading `/' from member names var/lib cpio: Removing leading `/' from member names var/lib/misc It is worse with the latest "cpio" or "pax", which tries to overwrite the host file system with the leading '/'. So the leading '/' of file names should be removed. This is consistent with the initramfs come with major distributions such as Fedora or Debian, etc. Signed-off-by: Thomas Chou <thomas@wytron.com.tw> Acked-by: Mike Frysinger<vapier@gentoo.org> Signed-off-by: Michal Marek <mmarek@suse.cz>
2010-12-01initramfs: Really fix build break on symbol-prefixed archsHendrik Brueckner1-2/+3
Define the __initramfs_size variable using VMLINUX_SYMBOL() to take care of symbol-prefixed architectures, for example, blackfin. Signed-off-by: Hendrik Brueckner <brueckner@linux.vnet.ibm.com> Cc: Mike Frysinger <vapier.adi@gmail.com> Cc: Hendrik Brueckner <brueckner@linux.vnet.ibm.com>, Cc: Michal Marek <mmarek@suse.cz> Cc: Sam Ravnborg <sam@ravnborg.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> [mmarek: leave out Makefile change, since d63f6d1 already takes care of the SYMBOL_PREFIX define] Signed-off-by: Michal Marek <mmarek@suse.cz>
2010-10-31initramfs: Fix initramfs size for 32-bit archesGeert Uytterhoeven1-3/+3
Commit ffe8018c3424 ("initramfs: fix initramfs size calculation") broke 32-bit big-endian arches like (on ARAnyM): VFS: Cannot open root device "hda1" or unknown-block(3,1) Please append a correct "root=" boot option; here are the available partitions: fe80 1059408 nfhd8 (driver?) fe81 921600 nfhd8p1 00000000-0000-0000-0000-000000000nfhd8p1 fe82 137807 nfhd8p2 00000000-0000-0000-0000-000000000nfhd8p2 0200 3280 fd0 (driver?) 0201 3280 fd1 (driver?) 0300 1059408 hda driver: ide-gd 0301 921600 hda1 00000000-0000-0000-0000-000000000hda1 0302 137807 hda2 00000000-0000-0000-0000-000000000hda2 Kernel panic - not syncing: VFS: Unable to mount root fs on unknown-block(3,1) As pointed out by Kerstin Jonsson <kerstin.jonsson@ericsson.com>, this is due to CONFIG_32BIT not being defined, so the initramfs size field is done as a 64-bit quad. On little-endian (like x86) this doesn matter, but on a big-endian machine the 32-bit reads will see the (zero) high bits. Only mips, s390, and score set CONFIG_32BIT for 32-bit builds, so fix it for all other 32-bit arches by inverting the logic and testing for CONFIG_64BIT, which should be defined on all 64-bit arches. Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org> [ I think we should just make it "u64" on all architectures and get rid of the whole #ifdef CONFIG_xxBIT - Linus ] Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-10-28Merge branch 'kbuild' of ↵Linus Torvalds6-125/+18
git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild-2.6 * 'kbuild' of git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild-2.6: initramfs: Fix build break on symbol-prefixed archs initramfs: fix initramfs size calculation initramfs: generalize initramfs_data.xxx.S variants scripts/kallsyms: Enable error messages while hush up unnecessary warnings scripts/setlocalversion: update comment kbuild: Use a single clean rule for kernel and external modules kbuild: Do not run make clean in $(srctree) scripts/mod/modpost.c: fix commentary accordingly to last changes kbuild: Really don't clean bounds.h and asm-offsets.h
2010-09-29initramfs: fix initramfs size calculationHendrik Brueckner1-5/+11
The size of a built-in initramfs is calculated in init/initramfs.c by "__initramfs_end - __initramfs_start". Those symbols are defined in the linker script include/asm-generic/vmlinux.lds.h: #define INIT_RAM_FS \ . = ALIGN(PAGE_SIZE); \ VMLINUX_SYMBOL(__initramfs_start) = .; \ *(.init.ramfs) \ VMLINUX_SYMBOL(__initramfs_end) = .; If the initramfs file has an odd number of bytes, the "__initramfs_end" symbol points to an odd address, for example, the symbols in the System.map might look like: 0000000000572000 T __initramfs_start 00000000005bcd05 T __initramfs_end <-- odd address At least on s390 this causes a problem: Certain s390 instructions, especially instructions for loading addresses (larl) or branch addresses must be on even addresses. The compiler loads the symbol addresses with the "larl" instruction. This instruction sets the last bit to 0 and, therefore, for odd size files, the calculated size is one byte less than it should be: 0000000000540a9c <populate_rootfs>: 540a9c: eb cf f0 78 00 24 stmg %r12,%r15,120(%r15), 540aa2: c0 10 00 01 8a af larl %r1,572000 <__initramfs_start> 540aa8: c0 c0 00 03 e1 2e larl %r12,5bcd04 <initramfs_end> (Instead of 5bcd05) ... 540abe: 1b c1 sr %r12,%r1 To fix the problem, this patch introduces the global variable __initramfs_size, which is calculated in the "usr/initramfs_data.S" file. The populate_rootfs() function can then use the start marker of the .init.ramfs section and the value of __initramfs_size for loading the initramfs. Because the start marker and size is sufficient, the __initramfs_end symbol is no longer needed and is removed. Signed-off-by: Michael Holzheu <holzheu@linux.vnet.ibm.com> Signed-off-by: Hendrik Brueckner <brueckner@linux.vnet.ibm.com> Reviewed-by: WANG Cong <xiyou.wangcong@gmail.com> Acked-by: Michal Marek <mmarek@suse.cz> Acked-by: "H. Peter Anvin" <hpa@zytor.com> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Michal Marek <mmarek@suse.cz>
2010-09-29initramfs: generalize initramfs_data.xxx.S variantsHendrik Brueckner6-120/+7
Remove initramfs_data.{lzo,lzma,gz,bz2}.S variants and use a common implementation in initramfs_data.S. The common implementation expects the file name of the initramfs to be defined in INITRAMFS_IMAGE. Change the Makefile to set the INITRAMFS_IMAGE define symbol according to the selected compression method. Signed-off-by: Hendrik Brueckner <brueckner@linux.vnet.ibm.com> Cc: WANG Cong <xiyou.wangcong@gmail.com> Acked-by: Michal Marek <mmarek@suse.cz> Acked-by: "H. Peter Anvin" <hpa@zytor.com> Cc: Hendrik Brueckner <brueckner@linux.vnet.ibm.com> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Michal Marek <mmarek@suse.cz>
2010-08-23Kconfig: delete duplicate wordStephan Sperber1-1/+1
Deleted a word which apeared twice. Signed-off-by: Stephan Sperber <sperberstephan@googlemail.com> Signed-off-by: Jiri Kosina <jkosina@suse.cz>
2010-05-27initramfs: add support for in-kernel initramfs compressed with LZOAlbin Tonnerre2-1/+33
Add the necessary parts to be enable the use of LZO-compressed initramfs build into the kernel. Signed-off-by: Albin Tonnerre <albin.tonnerre@free-electrons.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Michal Marek <mmarek@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-01-11Add LZO compression support for initramfs and old-style initrdAlbin Tonnerre1-5/+21
Signed-off-by: Albin Tonnerre <albin.tonnerre@free-electrons.com> Tested-by: Wu Zhangjin <wuzhangjin@gmail.com> Acked-by: "H. Peter Anvin" <hpa@zytor.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Tested-by: Russell King <rmk@arm.linux.org.uk> Acked-by: Russell King <rmk@arm.linux.org.uk> Cc: Ralf Baechle <ralf@linux-mips.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-12-12gen_init_cpio: fixed fwrite warningMike Frysinger1-1/+4
On compilers with security warnings enabled by default, we get: usr/gen_init_cpio.c: In function ‘cpio_mkfile’: usr/gen_init_cpio.c:357: warning: ignoring return value of ‘fwrite’, declared with attribute warn_unused_result So check the return value and handle errors accordingly. Signed-off-by: Mike Frysinger <vapier@gentoo.org> Signed-off-by: Michal Marek <mmarek@suse.cz>
2009-09-23Merge git://git.kernel.org/pub/scm/linux/kernel/git/sam/kbuild-nextLinus Torvalds2-1/+3
* git://git.kernel.org/pub/scm/linux/kernel/git/sam/kbuild-next: (30 commits) Use macros for .data.page_aligned section. Use macros for .bss.page_aligned section. Use new __init_task_data macro in arch init_task.c files. kbuild: Don't define ALIGN and ENTRY when preprocessing linker scripts. arm, cris, mips, sparc, powerpc, um, xtensa: fix build with bash 4.0 kbuild: add static to prototypes kbuild: fail build if recordmcount.pl fails kbuild: set -fconserve-stack option for gcc 4.5 kbuild: echo the record_mcount command gconfig: disable "typeahead find" search in treeviews kbuild: fix cc1 options check to ensure we do not use -fPIC when compiling checkincludes.pl: add option to remove duplicates in place markup_oops: use modinfo to avoid confusion with underscored module names checkincludes.pl: provide usage helper checkincludes.pl: close file as soon as we're done with it ctags: usability fix kernel hacking: move STRIP_ASM_SYMS from General gitignore usr/initramfs_data.cpio.bz2 and usr/initramfs_data.cpio.lzma kbuild: Check if linker supports the -X option kbuild: introduce ld-option ... Fix trivial conflict in scripts/basic/fixdep.c
2009-09-23Fix all -Wmissing-prototypes warnings in x86 defconfigTrevor Keith1-1/+1
Signed-off-by: Trevor Keith <tsrk@tsrk.net> Cc: Sam Ravnborg <sam@ravnborg.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-09-20gitignore usr/initramfs_data.cpio.bz2 and usr/initramfs_data.cpio.lzmaJaswinder Singh Rajput1-0/+2
usr/initramfs_data.cpio.bz2 and usr/initramfs_data.cpio.lzma are binary files should be ignored Signed-off-by: Jaswinder Singh Rajput <jaswinderrajput@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
2009-09-20kbuild: correct initramfs compression commentRobert P. J. Day1-1/+1
Fix the Makefile comment since bzip2 is now supported. Signed-off-by: Robert P. J. Day <rpjday@crashcourse.ca> Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
2009-03-31bzip2/lzma: quiet Kconfig warning for INITRAMFS_COMPRESSION_NONEH. Peter Anvin2-17/+1
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 <hpa@zytor.com>
2009-03-28bzip2/lzma: don't ask for compression mode for the default initramfsH. Peter Anvin1-10/+22
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 <hpa@zytor.com>