3 mainmenu "Buildroot $BR2_VERSION Configuration"
5 config BR2_HAVE_DOT_CONFIG
11 option env="BR2_VERSION_FULL"
19 option env="BUILD_DIR"
21 # Hidden config symbols for packages to check system gcc version
22 config BR2_HOST_GCC_VERSION
24 option env="HOST_GCC_VERSION"
26 config BR2_HOST_GCC_AT_LEAST_4_5
28 default y if BR2_HOST_GCC_VERSION = "4 5"
30 config BR2_HOST_GCC_AT_LEAST_4_6
32 default y if BR2_HOST_GCC_VERSION = "4 6"
33 select BR2_HOST_GCC_AT_LEAST_4_5
35 config BR2_HOST_GCC_AT_LEAST_4_7
37 default y if BR2_HOST_GCC_VERSION = "4 7"
38 select BR2_HOST_GCC_AT_LEAST_4_6
40 config BR2_HOST_GCC_AT_LEAST_4_8
42 default y if BR2_HOST_GCC_VERSION = "4 8"
43 select BR2_HOST_GCC_AT_LEAST_4_7
45 config BR2_HOST_GCC_AT_LEAST_4_9
47 default y if BR2_HOST_GCC_VERSION = "4 9"
48 select BR2_HOST_GCC_AT_LEAST_4_8
50 config BR2_HOST_GCC_AT_LEAST_5
52 default y if BR2_HOST_GCC_VERSION = "5"
53 select BR2_HOST_GCC_AT_LEAST_4_9
55 config BR2_HOST_GCC_AT_LEAST_6
57 default y if BR2_HOST_GCC_VERSION = "6"
58 select BR2_HOST_GCC_AT_LEAST_5
60 config BR2_HOST_GCC_AT_LEAST_7
62 default y if BR2_HOST_GCC_VERSION = "7"
63 select BR2_HOST_GCC_AT_LEAST_6
65 # Hidden boolean selected by packages in need of Java in order to build
67 config BR2_NEEDS_HOST_JAVA
70 # Hidden boolean selected by packages in need of javac in order to build
71 # (example: classpath)
72 config BR2_NEEDS_HOST_JAVAC
75 # Hidden boolean selected by packages in need of jar in order to build
76 # (example: classpath)
77 config BR2_NEEDS_HOST_JAR
80 # Hidden boolean selected by pre-built packages for x86, when they
81 # need to run on x86-64 machines (example: pre-built external
82 # toolchains, binary tools like SAM-BA, etc.).
83 config BR2_HOSTARCH_NEEDS_IA32_LIBS
86 # Hidden boolean selected by packages that need to build 32 bits
87 # binaries with the host compiler, even on 64 bits build machines (e.g
89 config BR2_HOSTARCH_NEEDS_IA32_COMPILER
92 # Hidden boolean selected by packages that need the host to have an
94 config BR2_NEEDS_HOST_UTF8_LOCALE
97 source "arch/Config.in"
104 string "Wget command"
105 default "wget --passive-ftp -nd -t 3"
108 string "Subversion (svn) command"
109 default "svn --non-interactive"
112 string "Bazaar (bzr) command"
123 config BR2_LOCALFILES
124 string "Local files retrieval command"
128 string "Secure copy (scp) command"
132 string "Secure shell (ssh) command"
136 string "Mercurial (hg) command"
140 string "zcat command"
143 Command to be used to extract a gzip'ed file to stdout. zcat
144 is identical to gunzip -c except that the former may not be
145 available on your system.
146 Default is "gzip -d -c"
147 Other possible values include "gunzip -c" or "zcat".
150 string "bzcat command"
153 Command to be used to extract a bzip2'ed file to stdout.
154 bzcat is identical to bunzip2 -c except that the former may
155 not be available on your system.
157 Other possible values include "bunzip2 -c" or "bzip2 -d -c".
160 string "xzcat command"
163 Command to be used to extract a xz'ed file to stdout.
167 string "lzcat command"
170 Command to be used to extract a lzip'ed file to stdout.
171 Default is "lzip -d -c"
173 config BR2_TAR_OPTIONS
177 Options to pass to tar when extracting the sources.
178 E.g. " -v --exclude='*.svn*'" to exclude all .svn internal files
183 config BR2_DEFCONFIG_FROM_ENV
185 option env="BR2_DEFCONFIG"
188 string "Location to save buildroot config"
189 default BR2_DEFCONFIG_FROM_ENV if BR2_DEFCONFIG_FROM_ENV != ""
190 default "$(CONFIG_DIR)/defconfig"
192 When running 'make savedefconfig', the defconfig file will be
193 saved in this location.
196 string "Download dir"
197 default "$(TOPDIR)/dl"
199 Directory to store all the source files that we need to fetch.
200 If the Linux shell environment has defined the BR2_DL_DIR
201 environment variable, then this overrides this configuration
204 The default is $(TOPDIR)/dl
208 default "$(BASE_DIR)/host"
210 Directory to store all the binary files that are built for the
211 host. This includes the cross compilation toolchain when
212 building the internal buildroot toolchain.
214 The default is $(BASE_DIR)/host
216 menu "Mirrors and Download locations"
218 config BR2_PRIMARY_SITE
219 string "Primary download site"
222 Primary site to download from. If this option is set then
223 buildroot will try to download package source first from this
224 site and try the default if the file is not found.
226 - URIs recognized by $(WGET)
227 - local URIs of the form file://absolutepath
228 - scp URIs of the form scp://[user@]host:path.
230 config BR2_PRIMARY_SITE_ONLY
231 bool "Only allow downloads from primary download site"
232 depends on BR2_PRIMARY_SITE != ""
234 If this option is enabled, downloads will only be attempted
235 from the primary download site. Other locations, like the
236 package's official download location or the backup download
237 site, will not be considered. Therefore, if the package is not
238 present on the primary site, the download fails.
240 This is useful for project developers who want to ensure that
241 the project can be built even if the upstream tarball
244 if !BR2_PRIMARY_SITE_ONLY
246 config BR2_BACKUP_SITE
247 string "Backup download site"
248 default "http://sources.buildroot.net"
250 Backup site to download from. If this option is set then
251 buildroot will fall back to download package sources from here
252 if the normal location fails.
254 config BR2_KERNEL_MIRROR
255 string "Kernel.org mirror"
256 default "https://cdn.kernel.org/pub"
258 kernel.org is mirrored on a number of servers around the
259 world. The following allows you to select your preferred
260 mirror. By default, a CDN is used, which automatically
261 redirects to a mirror geographically close to you.
263 Have a look on the kernel.org site for a list of mirrors, then
264 enter the URL to the base directory. Examples:
266 http://www.XX.kernel.org/pub (XX = country code)
267 http://mirror.aarnet.edu.au/pub/ftp.kernel.org
269 config BR2_GNU_MIRROR
270 string "GNU Software mirror"
271 default "http://ftpmirror.gnu.org"
273 GNU has multiple software mirrors scattered around the
274 world. The following allows you to select your preferred
275 mirror. By default, a generic address is used, which
276 automatically selects an up-to-date and local mirror.
278 Have a look on the gnu.org site for a list of mirrors, then
279 enter the URL to the base directory. Examples:
281 http://ftp.gnu.org/pub/gnu
282 http://mirror.aarnet.edu.au/pub/gnu
284 config BR2_LUAROCKS_MIRROR
285 string "LuaRocks mirror"
286 default "http://rocks.moonscript.org"
290 See http://luarocks.org
292 config BR2_CPAN_MIRROR
293 string "CPAN mirror (Perl packages)"
294 default "http://cpan.metacpan.org"
296 CPAN (Comprehensive Perl Archive Network) is a repository of
297 Perl packages. It has multiple software mirrors scattered
298 around the world. This option allows you to select a mirror.
300 The list of mirrors is available at:
301 http://search.cpan.org/mirror
308 int "Number of jobs to run simultaneously (0 for auto)"
311 Number of jobs to run simultaneously. If 0, determine
312 automatically according to number of CPUs on the host system.
315 bool "Enable compiler cache"
317 This option will enable the use of ccache, a compiler cache.
318 It will cache the result of previous builds to speed up future
319 builds. By default, the cache is stored in
320 $HOME/.buildroot-ccache.
322 Note that Buildroot does not try to invalidate the cache
323 contents when the compiler changes in an incompatible way.
324 Therefore, if you make a change to the compiler version and/or
325 configuration, you are responsible for purging the ccache
326 cache by removing the $HOME/.buildroot-ccache directory.
330 config BR2_CCACHE_DIR
331 string "Compiler cache location"
332 default "$(HOME)/.buildroot-ccache"
334 Where ccache should store cached files.
336 config BR2_CCACHE_INITIAL_SETUP
337 string "Compiler cache initial setup"
339 Initial ccache settings to apply, such as --max-files or
342 For example, if your project is known to require more space
343 than the default max cache size, then you might want to
344 increase the cache size to a suitable amount using the -M
347 The string you specify here is passed verbatim to ccache.
348 Refer to ccache documentation for more details.
350 These initial settings are applied after ccache has been
353 config BR2_CCACHE_USE_BASEDIR
354 bool "Use relative paths"
357 Allow ccache to convert absolute paths within the output
358 directory into relative paths.
360 During the build, many -I include directives are given with an
361 absolute path. These absolute paths end up in the hashes that
362 are computed by ccache. Therefore, when you build from a
363 different directory, the hash will be different and the cached
364 object will not be used.
366 To improve cache performance, set this option to y. This
367 allows ccache to rewrite absolute paths within the output
368 directory into relative paths. Note that only paths within the
369 output directory will be rewritten; therefore, if you change
370 BR2_HOST_DIR to point outside the output directory and
371 subsequently move it to a different location, this will lead
374 This option has as a result that the debug information in the
375 object files also has only relative paths. Therefore, make
376 sure you cd to the build directory before starting gdb. See
377 the section "COMPILING IN DIFFERENT DIRECTORIES" in the ccache
378 manual for more information.
382 config BR2_ENABLE_DEBUG
383 bool "build packages with debugging symbols"
385 Build packages with debugging symbols enabled. All libraries
386 and binaries in the 'staging' directory will have debugging
387 symbols, which allows remote debugging even if libraries and
388 binaries are stripped on the target. Whether libraries and
389 binaries are stripped on the target is controlled by the
390 BR2_STRIP_* options below.
394 prompt "gcc debug level"
397 Set the debug level for gcc
402 Debug level 1 produces minimal information, enough for making
403 backtraces in parts of the program that you don't plan to
404 debug. This includes descriptions of functions and external
405 variables, but no information about local variables and no
411 The default gcc debug level is 2
416 Level 3 includes extra information, such as all the macro
417 definitions present in the program. Some debuggers support
418 macro expansion when you use -g3.
422 config BR2_STRIP_strip
423 bool "strip target binaries"
424 depends on !BR2_PACKAGE_HOST_ELF2FLT
427 Binaries and libraries in the target filesystem will be
428 stripped using the normal 'strip' command. This allows to save
429 space, mainly by removing debugging symbols. Debugging symbols
430 on the target are needed for native debugging, but not when
431 remote debugging is used.
433 config BR2_STRIP_EXCLUDE_FILES
434 string "executables that should not be stripped"
435 depends on BR2_STRIP_strip
438 You may specify a space-separated list of binaries and
439 libraries here that should not be stripped on the target.
441 config BR2_STRIP_EXCLUDE_DIRS
442 string "directories that should be skipped when stripping"
443 depends on BR2_STRIP_strip
446 You may specify a space-separated list of directories that
447 should be skipped when stripping. Binaries and libraries in
448 these directories will not be touched. The directories should
449 be specified relative to the target directory, without leading
453 prompt "gcc optimization level"
454 default BR2_OPTIMIZE_S
456 Set the optimization level for gcc
458 config BR2_OPTIMIZE_0
459 bool "optimization level 0"
463 config BR2_OPTIMIZE_1
464 bool "optimization level 1"
466 Optimize. Optimizing compilation takes somewhat more time, and
467 a lot more memory for a large function. With -O, the compiler
468 tries to reduce code size and execution time, without
469 performing any optimizations that take a great deal of
470 compilation time. -O turns on the following optimization
471 flags: -fdefer-pop -fdelayed-branch -fguess-branch-probability
472 -fcprop-registers -floop-optimize -fif-conversion
473 -fif-conversion2 -ftree-ccp -ftree-dce -ftree-dominator-opts
474 -ftree-dse -ftree-ter -ftree-lrs -ftree-sra -ftree-copyrename
475 -ftree-fre -ftree-ch -funit-at-a-time -fmerge-constants. -O
476 also turns on -fomit-frame-pointer on machines where doing so
477 does not interfere with debugging.
479 config BR2_OPTIMIZE_2
480 bool "optimization level 2"
482 Optimize even more. GCC performs nearly all supported
483 optimizations that do not involve a space-speed tradeoff. The
484 compiler does not perform loop unrolling or function inlining
485 when you specify -O2. As compared to -O, this option increases
486 both compilation time and the performance of the generated
487 code. -O2 turns on all optimization flags specified by -O. It
488 also turns on the following optimization flags:
489 -fthread-jumps -fcrossjumping -foptimize-sibling-calls
490 -fcse-follow-jumps -fcse-skip-blocks -fgcse -fgcse-lm
491 -fexpensive-optimizations -fstrength-reduce
492 -frerun-cse-after-loop -frerun-loop-opt -fcaller-saves
493 -fpeephole2 -fschedule-insns -fschedule-insns2
494 -fsched-interblock -fsched-spec -fregmove -fstrict-aliasing
495 -fdelete-null-pointer-checks -freorder-blocks
496 -freorder-functions -falign-functions -falign-jumps
497 -falign-loops -falign-labels -ftree-vrp -ftree-pre. Please
498 note the warning under -fgcse about invoking -O2 on programs
499 that use computed gotos.
501 config BR2_OPTIMIZE_3
502 bool "optimization level 3"
504 Optimize yet more. -O3 turns on all optimizations specified by
505 -O2 and also turns on the -finline-functions, -funswitch-loops
506 and -fgcse-after-reload options.
508 config BR2_OPTIMIZE_G
509 bool "optimize for debugging"
510 depends on BR2_TOOLCHAIN_GCC_AT_LEAST_4_8
512 Optimize for debugging. This enables optimizations that do not
513 interfere with debugging. It should be the optimization level
514 of choice for the standard edit-compile-debug cycle, offering
515 a reasonable level of optimization while maintaining fast
516 compilation and a good debugging experience.
518 config BR2_OPTIMIZE_S
519 bool "optimize for size"
521 Optimize for size. -Os enables all -O2 optimizations that do
522 not typically increase code size. It also performs further
523 optimizations designed to reduce code size. -Os disables the
524 following optimization flags: -falign-functions -falign-jumps
525 -falign-loops -falign-labels -freorder-blocks
526 -freorder-blocks-and-partition -fprefetch-loop-arrays
527 -ftree-vect-loop-version
532 config BR2_GOOGLE_BREAKPAD_ENABLE
533 bool "Enable google-breakpad support"
534 select BR2_PACKAGE_GOOGLE_BREAKPAD
535 depends on BR2_INSTALL_LIBSTDCPP
536 depends on BR2_HOST_GCC_AT_LEAST_4_8 # C++11
537 depends on BR2_TOOLCHAIN_GCC_AT_LEAST_4_8 # C++11
538 depends on BR2_USE_WCHAR
539 depends on BR2_TOOLCHAIN_HAS_THREADS
540 depends on (BR2_TOOLCHAIN_USES_GLIBC || BR2_TOOLCHAIN_USES_UCLIBC)
541 depends on BR2_PACKAGE_GOOGLE_BREAKPAD_ARCH_SUPPORTS
542 depends on BR2_PACKAGE_HOST_GOOGLE_BREAKPAD_ARCH_SUPPORTS
544 This option will enable the use of google breakpad, a library
545 and tool suite that allows you to distribute an application to
546 users with compiler-provided debugging information removed,
547 record crashes in compact "minidump" files, send them back to
548 your server and produce C and C++ stack traces from these
549 minidumps. Breakpad can also write minidumps on request for
550 programs that have not crashed.
552 if BR2_GOOGLE_BREAKPAD_ENABLE
554 config BR2_GOOGLE_BREAKPAD_INCLUDE_FILES
555 string "List of executables and libraries to extract symbols from"
558 You may specify a space-separated list of binaries and
559 libraries with full paths relative to $(TARGET_DIR) of which
560 debug symbols will be dumped for further use with google
563 A directory structure that can be used by minidump-stackwalk
566 $(STAGING_DIR)/usr/share/google-breakpad-symbols
572 default BR2_SHARED_LIBS if BR2_BINFMT_SUPPORTS_SHARED
573 default BR2_STATIC_LIBS if !BR2_BINFMT_SUPPORTS_SHARED
575 Select the type of libraries you want to use on the target.
577 The default is to build dynamic libraries and use those on the
578 target filesystem, except when the architecture and/or the
579 selected binary format does not support shared libraries.
581 config BR2_STATIC_LIBS
584 Build and use only static libraries. No shared libraries will
585 be installed on the target. This potentially increases your
586 code size and should only be used if you know what you are
587 doing. Note that some packages may not be available when this
588 option is enabled, due to their need for dynamic library
591 config BR2_SHARED_LIBS
593 depends on BR2_BINFMT_SUPPORTS_SHARED
595 Build and use only shared libraries. This is the recommended
596 solution as it saves space and build time.
598 config BR2_SHARED_STATIC_LIBS
599 bool "both static and shared"
600 depends on BR2_BINFMT_SUPPORTS_SHARED
602 Build both shared and static libraries, but link executables
603 dynamically. While building both shared and static libraries
604 take more time and more disk space, having static libraries
605 may be useful to link some of the applications statically.
610 config BR2_PACKAGE_OVERRIDE_FILE
611 string "location of a package override file"
612 default "$(CONFIG_DIR)/local.mk"
614 A package override file is a short makefile that contains
615 variable definitions of the form <pkg>_OVERRIDE_SRCDIR, which
616 allows to tell Buildroot to use an existing directory as the
617 source directory for a particular package. See the Buildroot
618 documentation for more details on this feature.
620 config BR2_GLOBAL_PATCH_DIR
621 string "global patch directories"
623 You may specify a space separated list of one or more
624 directories containing global package patches. For a specific
625 version <packageversion> of a specific package <packagename>,
626 patches are applied as follows:
628 First, the default Buildroot patch set for the package is
629 applied from the package's directory in Buildroot.
631 Then for every directory - <global-patch-dir> - that exists in
632 BR2_GLOBAL_PATCH_DIR, if the directory
633 <global-patch-dir>/<packagename>/<packageversion>/ exists,
634 then all *.patch files in this directory will be applied.
636 Otherwise, if the directory <global-patch-dir>/<packagename>
637 exists, then all *.patch files in the directory will be
642 config BR2_COMPILER_PARANOID_UNSAFE_PATH
643 bool "paranoid check of library/header paths"
646 By default, when this option is disabled, when the Buildroot
647 cross-compiler will encounter an unsafe library or header path
648 (such as /usr/include, or /usr/lib), the compiler will display
651 By enabling this option, this warning is turned into an error,
652 which will completely abort the build when such unsafe paths
655 Note that this mechanism is available for both the internal
656 toolchain (through the toolchain wrapper and binutils patches)
657 and external toolchain backends (through the toolchain wrapper).
659 config BR2_REPRODUCIBLE
660 bool "Make the build reproducible (experimental)"
661 # SOURCE_DATE_EPOCH support in toolchain-wrapper requires GCC 4.4
662 depends on BR2_TOOLCHAIN_GCC_AT_LEAST_4_4
664 This option will remove all sources of non-reproducibility
665 from the build process. For a given Buildroot configuration,
666 this allows to generate exactly identical binaries from one
667 build to the other, including on different machines.
669 The current implementation is restricted to builds with the
670 same output directory. Many (absolute) paths are recorded in
671 intermediary files, and it is very likely that some of these
672 paths leak into the target rootfs. If you build with the
673 same O=... path, however, the result is identical.
675 This is labeled as an experimental feature, as not all
676 packages behave properly to ensure reproducibility.
680 comment "Security Hardening Options"
683 bool "Stack Smashing Protection"
684 default BR2_SSP_ALL if BR2_ENABLE_SSP # legacy
685 depends on BR2_TOOLCHAIN_HAS_SSP
687 Enable stack smashing protection support using GCC's
688 -fstack-protector option family.
691 http://www.linuxfromscratch.org/hints/downloads/files/ssp.txt
694 Note that this requires the toolchain to have SSP support.
695 This is always the case for glibc and eglibc toolchain, but is
696 optional in uClibc toolchains.
701 Disable stack-smashing protection.
703 config BR2_SSP_REGULAR
704 bool "-fstack-protector"
706 Emit extra code to check for buffer overflows, such as stack
707 smashing attacks. This is done by adding a guard variable to
708 functions with vulnerable objects. This includes functions
709 that call alloca, and functions with buffers larger than 8
710 bytes. The guards are initialized when a function is entered
711 and then checked when the function exits. If a guard check
712 fails, an error message is printed and the program exits.
714 config BR2_SSP_STRONG
715 bool "-fstack-protector-strong"
716 depends on BR2_TOOLCHAIN_GCC_AT_LEAST_4_9
718 Like -fstack-protector but includes additional functions to be
719 protected - those that have local array definitions, or have
720 references to local frame addresses.
722 comment "Stack Smashing Protection strong needs a toolchain w/ gcc >= 4.9"
723 depends on !BR2_TOOLCHAIN_GCC_AT_LEAST_4_9
726 bool "-fstack-protector-all"
728 Like -fstack-protector except that all functions are
729 protected. This option might have a significant performance
730 impact on the compiled binaries.
734 comment "Stack Smashing Protection needs a toolchain w/ SSP"
735 depends on !BR2_TOOLCHAIN_HAS_SSP
738 bool "RELRO Protection"
739 depends on BR2_SHARED_LIBS
741 Enable a link-time protection know as RELRO (RELocation Read Only)
742 which helps to protect from certain type of exploitation techniques
743 altering the content of some ELF sections.
745 config BR2_RELRO_NONE
748 Disables Relocation link-time protections.
750 config BR2_RELRO_PARTIAL
753 This option makes the dynamic section not writeable after
754 initialization (with almost no performance penalty).
756 config BR2_RELRO_FULL
759 This option includes the partial configuration, but also
760 marks the GOT as read-only at the cost of initialization time
761 during program loading, i.e every time an executable is started.
765 comment "RELocation Read Only (RELRO) needs shared libraries"
766 depends on !BR2_SHARED_LIBS
769 bool "Buffer-overflow Detection (FORTIFY_SOURCE)"
770 depends on BR2_TOOLCHAIN_USES_GLIBC
771 depends on !BR2_OPTIMIZE_0
773 Enable the _FORTIFY_SOURCE macro which introduces additional
774 checks to detect buffer-overflows in the following standard library
775 functions: memcpy, mempcpy, memmove, memset, strcpy, stpcpy,
776 strncpy, strcat, strncat, sprintf, vsprintf, snprintf, vsnprintf,
779 NOTE: This feature requires an optimization level of s/1/2/3/g
781 Support for this feature has been present since GCC 4.x.
783 config BR2_FORTIFY_SOURCE_NONE
786 Disables additional checks to detect buffer-overflows.
788 config BR2_FORTIFY_SOURCE_1
791 This option sets _FORTIFY_SOURCE to 1 and only introduces
792 checks that shouldn't change the behavior of conforming
793 programs. Adds checks at compile-time only.
795 config BR2_FORTIFY_SOURCE_2
798 This option sets _FORTIFY_SOURCES to 2 and some more
799 checking is added, but some conforming programs might fail.
800 Also adds checks at run-time (detected buffer overflow
801 terminates the program)
805 comment "Fortify Source needs a glibc toolchain and optimization"
806 depends on (!BR2_TOOLCHAIN_USES_GLIBC || BR2_OPTIMIZE_0)
809 source "toolchain/Config.in"
811 source "system/Config.in"
813 source "linux/Config.in"
815 source "package/Config.in"
817 source "fs/Config.in"
819 source "boot/Config.in"
821 source "package/Config.in.host"
823 source "Config.in.legacy"
825 source "$BR2_BUILD_DIR/.br2-external.in"