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.
335 If the Linux shell environment has defined the BR2_CCACHE_DIR
336 environment variable, then this overrides this configuration
339 config BR2_CCACHE_INITIAL_SETUP
340 string "Compiler cache initial setup"
342 Initial ccache settings to apply, such as --max-files or
345 For example, if your project is known to require more space
346 than the default max cache size, then you might want to
347 increase the cache size to a suitable amount using the -M
350 The string you specify here is passed verbatim to ccache.
351 Refer to ccache documentation for more details.
353 These initial settings are applied after ccache has been
356 config BR2_CCACHE_USE_BASEDIR
357 bool "Use relative paths"
360 Allow ccache to convert absolute paths within the output
361 directory into relative paths.
363 During the build, many -I include directives are given with an
364 absolute path. These absolute paths end up in the hashes that
365 are computed by ccache. Therefore, when you build from a
366 different directory, the hash will be different and the cached
367 object will not be used.
369 To improve cache performance, set this option to y. This
370 allows ccache to rewrite absolute paths within the output
371 directory into relative paths. Note that only paths within the
372 output directory will be rewritten; therefore, if you change
373 BR2_HOST_DIR to point outside the output directory and
374 subsequently move it to a different location, this will lead
377 This option has as a result that the debug information in the
378 object files also has only relative paths. Therefore, make
379 sure you cd to the build directory before starting gdb. See
380 the section "COMPILING IN DIFFERENT DIRECTORIES" in the ccache
381 manual for more information.
385 config BR2_ENABLE_DEBUG
386 bool "build packages with debugging symbols"
388 Build packages with debugging symbols enabled. All libraries
389 and binaries in the 'staging' directory will have debugging
390 symbols, which allows remote debugging even if libraries and
391 binaries are stripped on the target. Whether libraries and
392 binaries are stripped on the target is controlled by the
393 BR2_STRIP_* options below.
397 prompt "gcc debug level"
400 Set the debug level for gcc
405 Debug level 1 produces minimal information, enough for making
406 backtraces in parts of the program that you don't plan to
407 debug. This includes descriptions of functions and external
408 variables, but no information about local variables and no
414 The default gcc debug level is 2
419 Level 3 includes extra information, such as all the macro
420 definitions present in the program. Some debuggers support
421 macro expansion when you use -g3.
425 config BR2_STRIP_strip
426 bool "strip target binaries"
427 depends on !BR2_PACKAGE_HOST_ELF2FLT
430 Binaries and libraries in the target filesystem will be
431 stripped using the normal 'strip' command. This allows to save
432 space, mainly by removing debugging symbols. Debugging symbols
433 on the target are needed for native debugging, but not when
434 remote debugging is used.
436 config BR2_STRIP_EXCLUDE_FILES
437 string "executables that should not be stripped"
438 depends on BR2_STRIP_strip
441 You may specify a space-separated list of binaries and
442 libraries here that should not be stripped on the target.
444 config BR2_STRIP_EXCLUDE_DIRS
445 string "directories that should be skipped when stripping"
446 depends on BR2_STRIP_strip
449 You may specify a space-separated list of directories that
450 should be skipped when stripping. Binaries and libraries in
451 these directories will not be touched. The directories should
452 be specified relative to the target directory, without leading
456 prompt "gcc optimization level"
457 default BR2_OPTIMIZE_S
459 Set the optimization level for gcc
461 config BR2_OPTIMIZE_0
462 bool "optimization level 0"
466 config BR2_OPTIMIZE_1
467 bool "optimization level 1"
469 Optimize. Optimizing compilation takes somewhat more time, and
470 a lot more memory for a large function. With -O, the compiler
471 tries to reduce code size and execution time, without
472 performing any optimizations that take a great deal of
473 compilation time. -O turns on the following optimization
474 flags: -fdefer-pop -fdelayed-branch -fguess-branch-probability
475 -fcprop-registers -floop-optimize -fif-conversion
476 -fif-conversion2 -ftree-ccp -ftree-dce -ftree-dominator-opts
477 -ftree-dse -ftree-ter -ftree-lrs -ftree-sra -ftree-copyrename
478 -ftree-fre -ftree-ch -funit-at-a-time -fmerge-constants. -O
479 also turns on -fomit-frame-pointer on machines where doing so
480 does not interfere with debugging.
482 config BR2_OPTIMIZE_2
483 bool "optimization level 2"
485 Optimize even more. GCC performs nearly all supported
486 optimizations that do not involve a space-speed tradeoff. The
487 compiler does not perform loop unrolling or function inlining
488 when you specify -O2. As compared to -O, this option increases
489 both compilation time and the performance of the generated
490 code. -O2 turns on all optimization flags specified by -O. It
491 also turns on the following optimization flags:
492 -fthread-jumps -fcrossjumping -foptimize-sibling-calls
493 -fcse-follow-jumps -fcse-skip-blocks -fgcse -fgcse-lm
494 -fexpensive-optimizations -fstrength-reduce
495 -frerun-cse-after-loop -frerun-loop-opt -fcaller-saves
496 -fpeephole2 -fschedule-insns -fschedule-insns2
497 -fsched-interblock -fsched-spec -fregmove -fstrict-aliasing
498 -fdelete-null-pointer-checks -freorder-blocks
499 -freorder-functions -falign-functions -falign-jumps
500 -falign-loops -falign-labels -ftree-vrp -ftree-pre. Please
501 note the warning under -fgcse about invoking -O2 on programs
502 that use computed gotos.
504 config BR2_OPTIMIZE_3
505 bool "optimization level 3"
507 Optimize yet more. -O3 turns on all optimizations specified by
508 -O2 and also turns on the -finline-functions, -funswitch-loops
509 and -fgcse-after-reload options.
511 config BR2_OPTIMIZE_G
512 bool "optimize for debugging"
513 depends on BR2_TOOLCHAIN_GCC_AT_LEAST_4_8
515 Optimize for debugging. This enables optimizations that do not
516 interfere with debugging. It should be the optimization level
517 of choice for the standard edit-compile-debug cycle, offering
518 a reasonable level of optimization while maintaining fast
519 compilation and a good debugging experience.
521 config BR2_OPTIMIZE_S
522 bool "optimize for size"
524 Optimize for size. -Os enables all -O2 optimizations that do
525 not typically increase code size. It also performs further
526 optimizations designed to reduce code size. -Os disables the
527 following optimization flags: -falign-functions -falign-jumps
528 -falign-loops -falign-labels -freorder-blocks
529 -freorder-blocks-and-partition -fprefetch-loop-arrays
530 -ftree-vect-loop-version
535 config BR2_GOOGLE_BREAKPAD_ENABLE
536 bool "Enable google-breakpad support"
537 select BR2_PACKAGE_GOOGLE_BREAKPAD
538 depends on BR2_INSTALL_LIBSTDCPP
539 depends on BR2_HOST_GCC_AT_LEAST_4_8 # C++11
540 depends on BR2_TOOLCHAIN_GCC_AT_LEAST_4_8 # C++11
541 depends on BR2_USE_WCHAR
542 depends on BR2_TOOLCHAIN_HAS_THREADS
543 depends on (BR2_TOOLCHAIN_USES_GLIBC || BR2_TOOLCHAIN_USES_UCLIBC)
544 depends on BR2_PACKAGE_GOOGLE_BREAKPAD_ARCH_SUPPORTS
545 depends on BR2_PACKAGE_HOST_GOOGLE_BREAKPAD_ARCH_SUPPORTS
547 This option will enable the use of google breakpad, a library
548 and tool suite that allows you to distribute an application to
549 users with compiler-provided debugging information removed,
550 record crashes in compact "minidump" files, send them back to
551 your server and produce C and C++ stack traces from these
552 minidumps. Breakpad can also write minidumps on request for
553 programs that have not crashed.
555 if BR2_GOOGLE_BREAKPAD_ENABLE
557 config BR2_GOOGLE_BREAKPAD_INCLUDE_FILES
558 string "List of executables and libraries to extract symbols from"
561 You may specify a space-separated list of binaries and
562 libraries with full paths relative to $(TARGET_DIR) of which
563 debug symbols will be dumped for further use with google
566 A directory structure that can be used by minidump-stackwalk
569 $(STAGING_DIR)/usr/share/google-breakpad-symbols
575 default BR2_SHARED_LIBS if BR2_BINFMT_SUPPORTS_SHARED
576 default BR2_STATIC_LIBS if !BR2_BINFMT_SUPPORTS_SHARED
578 Select the type of libraries you want to use on the target.
580 The default is to build dynamic libraries and use those on the
581 target filesystem, except when the architecture and/or the
582 selected binary format does not support shared libraries.
584 config BR2_STATIC_LIBS
587 Build and use only static libraries. No shared libraries will
588 be installed on the target. This potentially increases your
589 code size and should only be used if you know what you are
590 doing. Note that some packages may not be available when this
591 option is enabled, due to their need for dynamic library
594 config BR2_SHARED_LIBS
596 depends on BR2_BINFMT_SUPPORTS_SHARED
598 Build and use only shared libraries. This is the recommended
599 solution as it saves space and build time.
601 config BR2_SHARED_STATIC_LIBS
602 bool "both static and shared"
603 depends on BR2_BINFMT_SUPPORTS_SHARED
605 Build both shared and static libraries, but link executables
606 dynamically. While building both shared and static libraries
607 take more time and more disk space, having static libraries
608 may be useful to link some of the applications statically.
613 config BR2_PACKAGE_OVERRIDE_FILE
614 string "location of a package override file"
615 default "$(CONFIG_DIR)/local.mk"
617 A package override file is a short makefile that contains
618 variable definitions of the form <pkg>_OVERRIDE_SRCDIR, which
619 allows to tell Buildroot to use an existing directory as the
620 source directory for a particular package. See the Buildroot
621 documentation for more details on this feature.
623 config BR2_GLOBAL_PATCH_DIR
624 string "global patch directories"
626 You may specify a space separated list of one or more
627 directories containing global package patches. For a specific
628 version <packageversion> of a specific package <packagename>,
629 patches are applied as follows:
631 First, the default Buildroot patch set for the package is
632 applied from the package's directory in Buildroot.
634 Then for every directory - <global-patch-dir> - that exists in
635 BR2_GLOBAL_PATCH_DIR, if the directory
636 <global-patch-dir>/<packagename>/<packageversion>/ exists,
637 then all *.patch files in this directory will be applied.
639 Otherwise, if the directory <global-patch-dir>/<packagename>
640 exists, then all *.patch files in the directory will be
645 config BR2_COMPILER_PARANOID_UNSAFE_PATH
646 bool "paranoid check of library/header paths"
649 By default, when this option is disabled, when the Buildroot
650 cross-compiler will encounter an unsafe library or header path
651 (such as /usr/include, or /usr/lib), the compiler will display
654 By enabling this option, this warning is turned into an error,
655 which will completely abort the build when such unsafe paths
658 Note that this mechanism is available for both the internal
659 toolchain (through the toolchain wrapper and binutils patches)
660 and external toolchain backends (through the toolchain wrapper).
662 config BR2_REPRODUCIBLE
663 bool "Make the build reproducible (experimental)"
664 # SOURCE_DATE_EPOCH support in toolchain-wrapper requires GCC 4.4
665 depends on BR2_TOOLCHAIN_GCC_AT_LEAST_4_4
667 This option will remove all sources of non-reproducibility
668 from the build process. For a given Buildroot configuration,
669 this allows to generate exactly identical binaries from one
670 build to the other, including on different machines.
672 The current implementation is restricted to builds with the
673 same output directory. Many (absolute) paths are recorded in
674 intermediary files, and it is very likely that some of these
675 paths leak into the target rootfs. If you build with the
676 same O=... path, however, the result is identical.
678 This is labeled as an experimental feature, as not all
679 packages behave properly to ensure reproducibility.
683 comment "Security Hardening Options"
686 bool "Stack Smashing Protection"
687 default BR2_SSP_ALL if BR2_ENABLE_SSP # legacy
688 depends on BR2_TOOLCHAIN_HAS_SSP
690 Enable stack smashing protection support using GCC's
691 -fstack-protector option family.
694 http://www.linuxfromscratch.org/hints/downloads/files/ssp.txt
697 Note that this requires the toolchain to have SSP support.
698 This is always the case for glibc and eglibc toolchain, but is
699 optional in uClibc toolchains.
704 Disable stack-smashing protection.
706 config BR2_SSP_REGULAR
707 bool "-fstack-protector"
709 Emit extra code to check for buffer overflows, such as stack
710 smashing attacks. This is done by adding a guard variable to
711 functions with vulnerable objects. This includes functions
712 that call alloca, and functions with buffers larger than 8
713 bytes. The guards are initialized when a function is entered
714 and then checked when the function exits. If a guard check
715 fails, an error message is printed and the program exits.
717 config BR2_SSP_STRONG
718 bool "-fstack-protector-strong"
719 depends on BR2_TOOLCHAIN_GCC_AT_LEAST_4_9
721 Like -fstack-protector but includes additional functions to be
722 protected - those that have local array definitions, or have
723 references to local frame addresses.
725 comment "Stack Smashing Protection strong needs a toolchain w/ gcc >= 4.9"
726 depends on !BR2_TOOLCHAIN_GCC_AT_LEAST_4_9
729 bool "-fstack-protector-all"
731 Like -fstack-protector except that all functions are
732 protected. This option might have a significant performance
733 impact on the compiled binaries.
737 comment "Stack Smashing Protection needs a toolchain w/ SSP"
738 depends on !BR2_TOOLCHAIN_HAS_SSP
741 bool "RELRO Protection"
742 depends on BR2_SHARED_LIBS
744 Enable a link-time protection know as RELRO (RELocation Read Only)
745 which helps to protect from certain type of exploitation techniques
746 altering the content of some ELF sections.
748 config BR2_RELRO_NONE
751 Disables Relocation link-time protections.
753 config BR2_RELRO_PARTIAL
756 This option makes the dynamic section not writeable after
757 initialization (with almost no performance penalty).
759 config BR2_RELRO_FULL
762 This option includes the partial configuration, but also
763 marks the GOT as read-only at the cost of initialization time
764 during program loading, i.e every time an executable is started.
768 comment "RELocation Read Only (RELRO) needs shared libraries"
769 depends on !BR2_SHARED_LIBS
772 bool "Buffer-overflow Detection (FORTIFY_SOURCE)"
773 depends on BR2_TOOLCHAIN_USES_GLIBC
774 depends on !BR2_OPTIMIZE_0
776 Enable the _FORTIFY_SOURCE macro which introduces additional
777 checks to detect buffer-overflows in the following standard library
778 functions: memcpy, mempcpy, memmove, memset, strcpy, stpcpy,
779 strncpy, strcat, strncat, sprintf, vsprintf, snprintf, vsnprintf,
782 NOTE: This feature requires an optimization level of s/1/2/3/g
784 Support for this feature has been present since GCC 4.x.
786 config BR2_FORTIFY_SOURCE_NONE
789 Disables additional checks to detect buffer-overflows.
791 config BR2_FORTIFY_SOURCE_1
794 This option sets _FORTIFY_SOURCE to 1 and only introduces
795 checks that shouldn't change the behavior of conforming
796 programs. Adds checks at compile-time only.
798 config BR2_FORTIFY_SOURCE_2
801 This option sets _FORTIFY_SOURCES to 2 and some more
802 checking is added, but some conforming programs might fail.
803 Also adds checks at run-time (detected buffer overflow
804 terminates the program)
808 comment "Fortify Source needs a glibc toolchain and optimization"
809 depends on (!BR2_TOOLCHAIN_USES_GLIBC || BR2_OPTIMIZE_0)
812 source "toolchain/Config.in"
814 source "system/Config.in"
816 source "linux/Config.in"
818 source "package/Config.in"
820 source "fs/Config.in"
822 source "boot/Config.in"
824 source "package/Config.in.host"
826 source "Config.in.legacy"
828 source "$BR2_BUILD_DIR/.br2-external.in"