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2021-03-25Merge https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-nextDavid S. Miller
Alexei Starovoitov says: ==================== pull-request: bpf-next 2021-03-24 The following pull-request contains BPF updates for your *net-next* tree. We've added 37 non-merge commits during the last 15 day(s) which contain a total of 65 files changed, 3200 insertions(+), 738 deletions(-). The main changes are: 1) Static linking of multiple BPF ELF files, from Andrii. 2) Move drop error path to devmap for XDP_REDIRECT, from Lorenzo. 3) Spelling fixes from various folks. ==================== Signed-off-by: David S. Miller <davem@davemloft.net>
2021-03-25Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/netDavid S. Miller
Signed-off-by: David S. Miller <davem@davemloft.net>
2021-03-10libbpf: xsk: Move barriers from libbpf_util.h to xsk.hBjörn Töpel
The only user of libbpf_util.h is xsk.h. Move the barriers to xsk.h, and remove libbpf_util.h. The barriers are used as an implementation detail, and should not be considered part of the stable API. Signed-off-by: Björn Töpel <bjorn.topel@intel.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20210310080929.641212-3-bjorn.topel@gmail.com
2021-03-08libbpf: Fix INSTALL flag orderGeorgi Valkov
It was reported ([0]) that having optional -m flag between source and destination arguments in install command breaks bpftools cross-build on MacOS. Move -m to the front to fix this issue. [0] https://github.com/openwrt/openwrt/pull/3959 Fixes: 7110d80d53f4 ("libbpf: Makefile set specified permission mode") Signed-off-by: Georgi Valkov <gvalkov@abv.bg> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Link: https://lore.kernel.org/bpf/20210308183038.613432-1-andrii@kernel.org
2021-03-04scripts/bpf: Abstract eBPF API target parameterJoe Stringer
Abstract out the target parameter so that upcoming commits, more than just the existing "helpers" target can be called to generate specific portions of docs from the eBPF UAPI headers. Signed-off-by: Joe Stringer <joe@cilium.io> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Reviewed-by: Quentin Monnet <quentin@isovalent.com> Acked-by: Toke Høiland-Jørgensen <toke@redhat.com> Link: https://lore.kernel.org/bpf/20210302171947.2268128-10-joe@cilium.io
2021-02-04libbpf: Stop using feature-detection MakefilesAndrii Nakryiko
Libbpf's Makefile relies on Linux tools infrastructure's feature detection framework, but libbpf's needs are very modest: it detects the presence of libelf and libz, both of which are mandatory. So it doesn't benefit much from the framework, but pays significant costs in terms of maintainability and debugging experience, when something goes wrong. The other feature detector, testing for the presernce of minimal BPF API in system headers is long obsolete as well, providing no value. So stop using feature detection and just assume the presence of libelf and libz during build time. Worst case, user will get a clear and actionable linker error, e.g.: /usr/bin/ld: cannot find -lelf On the other hand, we completely bypass recurring issues various users reported over time with false negatives of feature detection (libelf or libz not being detected, while they are actually present in the system). Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: John Fastabend <john.fastabend@gmail.com> Acked-by: Randy Dunlap <rdunlap@infradead.org> Link: https://lore.kernel.org/bpf/20210203203445.3356114-1-andrii@kernel.org
2020-11-19libbpf: Fix VERSIONED_SYM_COUNT number parsingJiri Olsa
We remove "other info" from "readelf -s --wide" output when parsing GLOBAL_SYM_COUNT variable, which was added in [1]. But we don't do that for VERSIONED_SYM_COUNT and it's failing the check_abi target on powerpc Fedora 33. The extra "other info" wasn't problem for VERSIONED_SYM_COUNT parsing until commit [2] added awk in the pipe, which assumes that the last column is symbol, but it can be "other info". Adding "other info" removal for VERSIONED_SYM_COUNT the same way as we did for GLOBAL_SYM_COUNT parsing. [1] aa915931ac3e ("libbpf: Fix readelf output parsing for Fedora") [2] 746f534a4809 ("tools/libbpf: Avoid counting local symbols in ABI check") Fixes: 746f534a4809 ("tools/libbpf: Avoid counting local symbols in ABI check") Signed-off-by: Jiri Olsa <jolsa@kernel.org> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20201118211350.1493421-1-jolsa@kernel.org
2020-09-29libbpf: Compile in PIC mode only for shared library caseAndrii Nakryiko
Libbpf compiles .o's for static and shared library modes separately, so no need to specify -fPIC for both. Keep it only for shared library mode. Signed-off-by: Andrii Nakryiko <andriin@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Martin KaFai Lau <kafai@fb.com> Link: https://lore.kernel.org/bpf/20200929220604.833631-3-andriin@fb.com
2020-09-29libbpf: Compile libbpf under -O2 level by default and catch extra warningsAndrii Nakryiko
For some reason compiler doesn't complain about uninitialized variable, fixed in previous patch, if libbpf is compiled without -O2 optimization level. So do compile it with -O2 and never let similar issue slip by again. -Wall is added unconditionally, so no need to specify it again. Signed-off-by: Andrii Nakryiko <andriin@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Martin KaFai Lau <kafai@fb.com> Link: https://lore.kernel.org/bpf/20200929220604.833631-2-andriin@fb.com
2020-09-22Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/netDavid S. Miller
Two minor conflicts: 1) net/ipv4/route.c, adding a new local variable while moving another local variable and removing it's initial assignment. 2) drivers/net/dsa/microchip/ksz9477.c, overlapping changes. One pretty prints the port mode differently, whilst another changes the driver to try and obtain the port mode from the port node rather than the switch node. Signed-off-by: David S. Miller <davem@davemloft.net>
2020-09-08tools/libbpf: Avoid counting local symbols in ABI checkTony Ambardar
Encountered the following failure building libbpf from kernel 5.8.5 sources with GCC 8.4.0 and binutils 2.34: (long paths shortened) Warning: Num of global symbols in sharedobjs/libbpf-in.o (234) does NOT match with num of versioned symbols in libbpf.so (236). Please make sure all LIBBPF_API symbols are versioned in libbpf.map. --- libbpf_global_syms.tmp 2020-09-02 07:30:58.920084380 +0000 +++ libbpf_versioned_syms.tmp 2020-09-02 07:30:58.924084388 +0000 @@ -1,3 +1,5 @@ +_fini +_init bpf_btf_get_fd_by_id bpf_btf_get_next_id bpf_create_map make[4]: *** [Makefile:210: check_abi] Error 1 Investigation shows _fini and _init are actually local symbols counted amongst global ones: $ readelf --dyn-syms --wide libbpf.so|head -10 Symbol table '.dynsym' contains 343 entries: Num: Value Size Type Bind Vis Ndx Name 0: 00000000 0 NOTYPE LOCAL DEFAULT UND 1: 00004098 0 SECTION LOCAL DEFAULT 11 2: 00004098 8 FUNC LOCAL DEFAULT 11 _init@@LIBBPF_0.0.1 3: 00023040 8 FUNC LOCAL DEFAULT 14 _fini@@LIBBPF_0.0.1 4: 00000000 0 OBJECT GLOBAL DEFAULT ABS LIBBPF_0.0.4 5: 00000000 0 OBJECT GLOBAL DEFAULT ABS LIBBPF_0.0.1 6: 0000ffa4 8 FUNC GLOBAL DEFAULT 12 bpf_object__find_map_by_offset@@LIBBPF_0.0.1 A previous commit filtered global symbols in sharedobjs/libbpf-in.o. Do the same with the libbpf.so DSO for consistent comparison. Fixes: 306b267cb3c4 ("libbpf: Verify versioned symbols") Signed-off-by: Tony Ambardar <Tony.Ambardar@gmail.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Andrii Nakryiko <andriin@fb.com> Link: https://lore.kernel.org/bpf/20200905214831.1565465-1-Tony.Ambardar@gmail.com
2020-09-03libbpf: Remove arch-specific include path in MakefileNaveen N. Rao
Ubuntu mainline builds for ppc64le are failing with the below error (*): CALL /home/kernel/COD/linux/scripts/atomic/check-atomics.sh DESCEND bpf/resolve_btfids Auto-detecting system features: ... libelf: [ [32mon[m ] ... zlib: [ [32mon[m ] ... bpf: [ [31mOFF[m ] BPF API too old make[6]: *** [Makefile:295: bpfdep] Error 1 make[5]: *** [Makefile:54: /home/kernel/COD/linux/debian/build/build-generic/tools/bpf/resolve_btfids//libbpf.a] Error 2 make[4]: *** [Makefile:71: bpf/resolve_btfids] Error 2 make[3]: *** [/home/kernel/COD/linux/Makefile:1890: tools/bpf/resolve_btfids] Error 2 make[2]: *** [/home/kernel/COD/linux/Makefile:335: __build_one_by_one] Error 2 make[2]: Leaving directory '/home/kernel/COD/linux/debian/build/build-generic' make[1]: *** [Makefile:185: __sub-make] Error 2 make[1]: Leaving directory '/home/kernel/COD/linux' resolve_btfids needs to be build as a host binary and it needs libbpf. However, libbpf Makefile hardcodes an include path utilizing $(ARCH). This results in mixing of cross-architecture headers resulting in a build failure. The specific header include path doesn't seem necessary for a libbpf build. Hence, remove the same. (*) https://kernel.ubuntu.com/~kernel-ppa/mainline/v5.9-rc3/ppc64el/log Reported-by: Vaidyanathan Srinivasan <svaidy@linux.ibm.com> Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Andrii Nakryiko <andriin@fb.com> Link: https://lore.kernel.org/bpf/20200902084246.1513055-1-naveen.n.rao@linux.vnet.ibm.com
2020-08-28tools, bpf/build: Cleanup feature files on make cleanJesper Dangaard Brouer
The system for "Auto-detecting system features" located under tools/build/ are (currently) used by perf, libbpf and bpftool. It can contain stalled feature detection files, which are not cleaned up by libbpf and bpftool on make clean (side-note: perf tool is correct). Fix this by making the users invoke the make clean target. Some details about the changes. The libbpf Makefile already had a clean-config target (which seems to be copy-pasted from perf), but this target was not "connected" (a make dependency) to clean target. Choose not to rename target as someone might be using it. Did change the output from "CLEAN config" to "CLEAN feature-detect", to make it more clear what happens. This is related to the complaint and troubleshooting in the following link: https://lore.kernel.org/lkml/20200818122007.2d1cfe2d@carbon/ Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Jiri Olsa <jolsa@redhat.com> Link: https://lore.kernel.org/lkml/20200818122007.2d1cfe2d@carbon/ Link: https://lore.kernel.org/bpf/159851841661.1072907.13770213104521805592.stgit@firesoul
2020-08-20bpf: Add kernel module with user mode driver that populates bpffs.Alexei Starovoitov
Add kernel module with user mode driver that populates bpffs with BPF iterators. $ mount bpffs /my/bpffs/ -t bpf $ ls -la /my/bpffs/ total 4 drwxrwxrwt 2 root root 0 Jul 2 00:27 . drwxr-xr-x 19 root root 4096 Jul 2 00:09 .. -rw------- 1 root root 0 Jul 2 00:27 maps.debug -rw------- 1 root root 0 Jul 2 00:27 progs.debug The user mode driver will load BPF Type Formats, create BPF maps, populate BPF maps, load two BPF programs, attach them to BPF iterators, and finally send two bpf_link IDs back to the kernel. The kernel will pin two bpf_links into newly mounted bpffs instance under names "progs.debug" and "maps.debug". These two files become human readable. $ cat /my/bpffs/progs.debug id name attached 11 dump_bpf_map bpf_iter_bpf_map 12 dump_bpf_prog bpf_iter_bpf_prog 27 test_pkt_access 32 test_main test_pkt_access test_pkt_access 33 test_subprog1 test_pkt_access_subprog1 test_pkt_access 34 test_subprog2 test_pkt_access_subprog2 test_pkt_access 35 test_subprog3 test_pkt_access_subprog3 test_pkt_access 36 new_get_skb_len get_skb_len test_pkt_access 37 new_get_skb_ifindex get_skb_ifindex test_pkt_access 38 new_get_constant get_constant test_pkt_access The BPF program dump_bpf_prog() in iterators.bpf.c is printing this data about all BPF programs currently loaded in the system. This information is unstable and will change from kernel to kernel as ".debug" suffix conveys. Signed-off-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Link: https://lore.kernel.org/bpf/20200819042759.51280-4-alexei.starovoitov@gmail.com
2020-08-18tools: Remove feature-libelf-mmap feature detectionAndrii Nakryiko
It's trivial to handle missing ELF_C_MMAP_READ support in libelf the way that objtool has solved it in ("774bec3fddcc objtool: Add fallback from ELF_C_READ_MMAP to ELF_C_READ"). So instead of having an entire feature detector for that, just do what objtool does for perf and libbpf. And keep their Makefiles a bit simpler. Signed-off-by: Andrii Nakryiko <andriin@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20200819013607.3607269-5-andriin@fb.com
2020-08-18libbpf: Remove any use of reallocarray() in libbpfAndrii Nakryiko
Re-implement glibc's reallocarray() for libbpf internal-only use. reallocarray(), unfortunately, is not available in all versions of glibc, so requires extra feature detection and using reallocarray() stub from <tools/libc_compat.h> and COMPAT_NEED_REALLOCARRAY. All this complicates build of libbpf unnecessarily and is just a maintenance burden. Instead, it's trivial to implement libbpf-specific internal version and use it throughout libbpf. Which is what this patch does, along with converting some realloc() uses that should really have been reallocarray() in the first place. Signed-off-by: Andrii Nakryiko <andriin@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20200819013607.3607269-2-andriin@fb.com
2020-08-18libbpf: Disable -Wswitch-enum compiler warningAndrii Nakryiko
That compilation warning is more annoying, than helpful. Signed-off-by: Andrii Nakryiko <andriin@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20200818213356.2629020-2-andriin@fb.com
2020-06-01libbpf: Use .so dynamic symbols for abi checkYauheni Kaliuta
Since dynamic symbols are used for dynamic linking it makes sense to use them (readelf --dyn-syms) for abi check. Found with some configuration on powerpc where linker puts local *.plt_call.* symbols into .so. Signed-off-by: Yauheni Kaliuta <yauheni.kaliuta@redhat.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Andrii Nakryiko <andriin@fb.com> Link: https://lore.kernel.org/bpf/20200525061846.16524-1-yauheni.kaliuta@redhat.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2020-06-01libbpf: Install headers as part of make installNikolay Borisov
Current 'make install' results in only pkg-config and library binaries being installed. For consistency also install headers as part of "make install" Signed-off-by: Nikolay Borisov <nborisov@suse.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Andrii Nakryiko <andriin@fb.com> Link: https://lore.kernel.org/bpf/20200526174612.5447-1-nborisov@suse.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2020-01-13libbpf: Clean up bpf_helper_defs.h generation outputAndrii Nakryiko
bpf_helpers_doc.py script, used to generate bpf_helper_defs.h, unconditionally emits one informational message to stderr. Remove it and preserve stderr to contain only relevant errors. Also make sure script invocations command is muted by default in libbpf's Makefile. Signed-off-by: Andrii Nakryiko <andriin@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20200113073143.1779940-3-andriin@fb.com
2020-01-09libbpf,selftests/bpf: Fix clean targetsAndrii Nakryiko
Libbpf's clean target should clean out generated files in $(OUTPUT) directory and not make assumption that $(OUTPUT) directory is current working directory. Selftest's Makefile should delegate cleaning of libbpf-generated files to libbpf's Makefile. This ensures more robust clean up. Signed-off-by: Andrii Nakryiko <andriin@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20200110051716.1591485-2-andriin@fb.com
2019-12-31Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/netDavid S. Miller
Simple overlapping changes in bpf land wrt. bpf_helper_defs.h handling. Signed-off-by: David S. Miller <davem@davemloft.net>
2019-12-23libbpf: Fix build on read-only filesystemsNamhyung Kim
I got the following error when I tried to build perf on a read-only filesystem with O=dir option. $ cd /some/where/ro/linux/tools/perf $ make O=$HOME/build/perf ... CC /home/namhyung/build/perf/lib.o /bin/sh: bpf_helper_defs.h: Read-only file system make[3]: *** [Makefile:184: bpf_helper_defs.h] Error 1 make[2]: *** [Makefile.perf:778: /home/namhyung/build/perf/libbpf.a] Error 2 make[2]: *** Waiting for unfinished jobs.... LD /home/namhyung/build/perf/libperf-in.o AR /home/namhyung/build/perf/libperf.a PERF_VERSION = 5.4.0 make[1]: *** [Makefile.perf:225: sub-make] Error 2 make: *** [Makefile:70: all] Error 2 It was becaused bpf_helper_defs.h was generated in current directory. Move it to OUTPUT directory. Signed-off-by: Namhyung Kim <namhyung@kernel.org> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Tested-by: Andrii Nakryiko <andriin@fb.com> Acked-by: Andrii Nakryiko <andriin@fb.com> Link: https://lore.kernel.org/bpf/20191223061326.843366-1-namhyung@kernel.org
2019-12-18libbpf: Fix libbpf_common.h when installing libbpf through 'make install'Toke Høiland-Jørgensen
This fixes two issues with the newly introduced libbpf_common.h file: - The header failed to include <string.h> for the definition of memset() - The new file was not included in the install_headers rule in the Makefile Both of these issues cause breakage when installing libbpf with 'make install' and trying to use it in applications. Fixes: 544402d4b493 ("libbpf: Extract common user-facing helpers") Signed-off-by: Toke Høiland-Jørgensen <toke@redhat.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Yonghong Song <yhs@fb.com> Link: https://lore.kernel.org/bpf/20191217112810.768078-1-toke@redhat.com
2019-12-15libbpf: Support libbpf-provided extern variablesAndrii Nakryiko
Add support for extern variables, provided to BPF program by libbpf. Currently the following extern variables are supported: - LINUX_KERNEL_VERSION; version of a kernel in which BPF program is executing, follows KERNEL_VERSION() macro convention, can be 4- and 8-byte long; - CONFIG_xxx values; a set of values of actual kernel config. Tristate, boolean, strings, and integer values are supported. Set of possible values is determined by declared type of extern variable. Supported types of variables are: - Tristate values. Are represented as `enum libbpf_tristate`. Accepted values are **strictly** 'y', 'n', or 'm', which are represented as TRI_YES, TRI_NO, or TRI_MODULE, respectively. - Boolean values. Are represented as bool (_Bool) types. Accepted values are 'y' and 'n' only, turning into true/false values, respectively. - Single-character values. Can be used both as a substritute for bool/tristate, or as a small-range integer: - 'y'/'n'/'m' are represented as is, as characters 'y', 'n', or 'm'; - integers in a range [-128, 127] or [0, 255] (depending on signedness of char in target architecture) are recognized and represented with respective values of char type. - Strings. String values are declared as fixed-length char arrays. String of up to that length will be accepted and put in first N bytes of char array, with the rest of bytes zeroed out. If config string value is longer than space alloted, it will be truncated and warning message emitted. Char array is always zero terminated. String literals in config have to be enclosed in double quotes, just like C-style string literals. - Integers. 8-, 16-, 32-, and 64-bit integers are supported, both signed and unsigned variants. Libbpf enforces parsed config value to be in the supported range of corresponding integer type. Integers values in config can be: - decimal integers, with optional + and - signs; - hexadecimal integers, prefixed with 0x or 0X; - octal integers, starting with 0. Config file itself is searched in /boot/config-$(uname -r) location with fallback to /proc/config.gz, unless config path is specified explicitly through bpf_object_open_opts' kernel_config_path option. Both gzipped and plain text formats are supported. Libbpf adds explicit dependency on zlib because of this, but this shouldn't be a problem, given libelf already depends on zlib. All detected extern variables, are put into a separate .extern internal map. It, similarly to .rodata map, is marked as read-only from BPF program side, as well as is frozen on load. This allows BPF verifier to track extern values as constants and perform enhanced branch prediction and dead code elimination. This can be relied upon for doing kernel version/feature detection and using potentially unsupported field relocations or BPF helpers in a CO-RE-based BPF program, while still having a single version of BPF program running on old and new kernels. Selftests are validating this explicitly for unexisting BPF helper. Signed-off-by: Andrii Nakryiko <andriin@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20191214014710.3449601-3-andriin@fb.com
2019-12-15libbpf: Fix readelf output parsing for FedoraThadeu Lima de Souza Cascardo
Fedora binutils has been patched to show "other info" for a symbol at the end of the line. This was done in order to support unmaintained scripts that would break with the extra info. [1] [1] https://src.fedoraproject.org/rpms/binutils/c/b8265c46f7ddae23a792ee8306fbaaeacba83bf8 This in turn has been done to fix the build of ruby, because of checksec. [2] Thanks Michael Ellerman for the pointer. [2] https://bugzilla.redhat.com/show_bug.cgi?id=1479302 As libbpf Makefile is not unmaintained, we can simply deal with either output format, by just removing the "other info" field, as it always comes inside brackets. Fixes: 3464afdf11f9 (libbpf: Fix readelf output parsing on powerpc with recent binutils) Reported-by: Justin Forbes <jmforbes@linuxtx.org> Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Andrii Nakryiko <andriin@fb.com> Cc: Aurelien Jarno <aurelien@aurel32.net> Link: https://lore.kernel.org/bpf/20191213101114.GA3986@calabresa
2019-12-04selftests/bpf: Bring back c++ include/link testStanislav Fomichev
Commit 5c26f9a78358 ("libbpf: Don't use cxx to test_libpf target") converted existing c++ test to c. We still want to include and link against libbpf from c++ code, so reinstate this test back, this time in a form of a selftest with a clear comment about its purpose. v2: * -lelf -> $(LDLIBS) (Andrii Nakryiko) Fixes: 5c26f9a78358 ("libbpf: Don't use cxx to test_libpf target") Signed-off-by: Stanislav Fomichev <sdf@google.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Andrii Nakryiko <andriin@fb.com> Link: https://lore.kernel.org/bpf/20191202215931.248178-1-sdf@google.com
2019-12-02libbpf: Fix readelf output parsing on powerpc with recent binutilsAurelien Jarno
On powerpc with recent versions of binutils, readelf outputs an extra field when dumping the symbols of an object file. For example: 35: 0000000000000838 96 FUNC LOCAL DEFAULT [<localentry>: 8] 1 btf_is_struct The extra "[<localentry>: 8]" prevents the GLOBAL_SYM_COUNT variable to be computed correctly and causes the check_abi target to fail. Fix that by looking for the symbol name in the last field instead of the 8th one. This way it should also cope with future extra fields. Signed-off-by: Aurelien Jarno <aurelien@aurel32.net> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Tested-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/bpf/20191201195728.4161537-1-aurelien@aurel32.net
2019-11-27libbpf: Fix up generation of bpf_helper_defs.hArnaldo Carvalho de Melo
$ make -C tools/perf build-test does, ends up with these two problems: make[3]: *** No rule to make target '/tmp/tmp.zq13cHILGB/perf-5.3.0/include/uapi/linux/bpf.h', needed by 'bpf_helper_defs.h'. Stop. make[3]: *** Waiting for unfinished jobs.... make[2]: *** [Makefile.perf:757: /tmp/tmp.zq13cHILGB/perf-5.3.0/tools/lib/bpf/libbpf.a] Error 2 make[2]: *** Waiting for unfinished jobs.... Because $(srcdir) points to the /tmp/tmp.zq13cHILGB/perf-5.3.0 directory and we need '/tools/ after that variable, and after fixing this then we get to another problem: /bin/sh: /home/acme/git/perf/tools/scripts/bpf_helpers_doc.py: No such file or directory make[3]: *** [Makefile:184: bpf_helper_defs.h] Error 127 make[3]: *** Deleting file 'bpf_helper_defs.h' LD /tmp/build/perf/libapi-in.o make[2]: *** [Makefile.perf:778: /tmp/build/perf/libbpf.a] Error 2 make[2]: *** Waiting for unfinished jobs.... Because this requires something outside the tools/ directories that gets collected into perf's detached tarballs, to fix it just add it to tools/perf/MANIFEST, which this patch does, now it works for that case and also for all these other cases. Fixes: e01a75c15969 ("libbpf: Move bpf_{helpers, helper_defs, endian, tracing}.h into libbpf") Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Alexei Starovoitov <ast@kernel.org> Cc: Andrii Nakryiko <andriin@fb.com> Cc: Daniel Borkmann <daniel@iogearbox.net> Cc: Jiri Olsa <jolsa@kernel.org> Cc: Martin KaFai Lau <kafai@fb.com> Cc: Namhyung Kim <namhyung@kernel.org> Link: https://lkml.kernel.org/n/tip-4pnkg2vmdvq5u6eivc887wen@git.kernel.org Link: https://lore.kernel.org/bpf/20191126151045.GB19483@kernel.org
2019-11-27libbpf: Fix Makefile' libbpf symbol mismatch diagnosticAndrii Nakryiko
Fix Makefile's diagnostic diff output when there is LIBBPF_API-versioned symbols mismatch. Fixes: 1bd63524593b ("libbpf: handle symbol versioning properly for libbpf.a") Signed-off-by: Andrii Nakryiko <andriin@fb.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Yonghong Song <yhs@fb.com> Link: https://lore.kernel.org/bpf/20191127200134.1360660-1-andriin@fb.com
2019-10-26Merge git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-nextDavid S. Miller
Daniel Borkmann says: ==================== pull-request: bpf-next 2019-10-27 The following pull-request contains BPF updates for your *net-next* tree. We've added 52 non-merge commits during the last 11 day(s) which contain a total of 65 files changed, 2604 insertions(+), 1100 deletions(-). The main changes are: 1) Revolutionize BPF tracing by using in-kernel BTF to type check BPF assembly code. The work here teaches BPF verifier to recognize kfree_skb()'s first argument as 'struct sk_buff *' in tracepoints such that verifier allows direct use of bpf_skb_event_output() helper used in tc BPF et al (w/o probing memory access) that dumps skb data into perf ring buffer. Also add direct loads to probe memory in order to speed up/replace bpf_probe_read() calls, from Alexei Starovoitov. 2) Big batch of changes to improve libbpf and BPF kselftests. Besides others: generalization of libbpf's CO-RE relocation support to now also include field existence relocations, revamp the BPF kselftest Makefile to add test runner concept allowing to exercise various ways to build BPF programs, and teach bpf_object__open() and friends to automatically derive BPF program type/expected attach type from section names to ease their use, from Andrii Nakryiko. 3) Fix deadlock in stackmap's build-id lookup on rq_lock(), from Song Liu. 4) Allow to read BTF as raw data from bpftool. Most notable use case is to dump /sys/kernel/btf/vmlinux through this, from Jiri Olsa. 5) Use bpf_redirect_map() helper in libbpf's AF_XDP helper prog which manages to improve "rx_drop" performance by ~4%., from Björn Töpel. 6) Fix to restore the flow dissector after reattach BPF test and also fix error handling in bpf_helper_defs.h generation, from Jakub Sitnicki. 7) Improve verifier's BTF ctx access for use outside of raw_tp, from Martin KaFai Lau. 8) Improve documentation for AF_XDP with new sections and to reflect latest features, from Magnus Karlsson. 9) Add back 'version' section parsing to libbpf for old kernels, from John Fastabend. 10) Fix strncat bounds error in libbpf's libbpf_prog_type_by_name(), from KP Singh. 11) Turn on -mattr=+alu32 in LLVM by default for BPF kselftests in order to improve insn coverage for built BPF progs, from Yonghong Song. 12) Misc minor cleanups and fixes, from various others. ==================== Signed-off-by: David S. Miller <davem@davemloft.net>
2019-10-20scripts/bpf: Print an error when known types list needs updatingJakub Sitnicki
Don't generate a broken bpf_helper_defs.h header if the helper script needs updating because it doesn't recognize a newly added type. Instead print an error that explains why the build is failing, clean up the partially generated header and stop. v1->v2: - Switched from temporary file to .DELETE_ON_ERROR. Fixes: 456a513bb5d4 ("scripts/bpf: Emit an #error directive known types list needs updating") Suggested-by: Andrii Nakryiko <andriin@fb.com> Signed-off-by: Jakub Sitnicki <jakub@cloudflare.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Yonghong Song <yhs@fb.com> Acked-by: Andrii Nakryiko <andriin@fb.com> Link: https://lore.kernel.org/bpf/20191020112344.19395-1-jakub@cloudflare.com
2019-10-20Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/netDavid S. Miller
Several cases of overlapping changes which were for the most part trivially resolvable. Signed-off-by: David S. Miller <davem@davemloft.net>
2019-10-12libbpf: Add C/LDFLAGS to libbpf.so and test_libpf targetsIvan Khoronzhuk
In case of C/LDFLAGS there is no way to pass them correctly to build command, for instance when --sysroot is used or external libraries are used, like -lelf, wich can be absent in toolchain. This can be used for samples/bpf cross-compiling allowing to get elf lib from sysroot. Signed-off-by: Ivan Khoronzhuk <ivan.khoronzhuk@linaro.org> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Andrii Nakryiko <andriin@fb.com> Link: https://lore.kernel.org/bpf/20191011002808.28206-13-ivan.khoronzhuk@linaro.org
2019-10-12libbpf: Don't use cxx to test_libpf targetIvan Khoronzhuk
No need to use C++ for test_libbpf target when libbpf is on C and it can be tested with C, after this change the CXXFLAGS in makefiles can be avoided, at least in bpf samples, when sysroot is used, passing same C/LDFLAGS as for lib. Add "return 0" in test_libbpf to avoid warn, but also remove spaces at start of the lines to keep same style and avoid warns while apply. Signed-off-by: Ivan Khoronzhuk <ivan.khoronzhuk@linaro.org> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Andrii Nakryiko <andriin@fb.com> Link: https://lore.kernel.org/bpf/20191011002808.28206-12-ivan.khoronzhuk@linaro.org
2019-10-08libbpf: Add BPF_CORE_READ/BPF_CORE_READ_INTO helpersAndrii Nakryiko
Add few macros simplifying BCC-like multi-level probe reads, while also emitting CO-RE relocations for each read. Signed-off-by: Andrii Nakryiko <andriin@fb.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: John Fastabend <john.fastabend@gmail.com> Acked-by: Song Liu <songliubraving@fb.com> Link: https://lore.kernel.org/bpf/20191008175942.1769476-7-andriin@fb.com
2019-10-08libbpf: Move bpf_{helpers, helper_defs, endian, tracing}.h into libbpfAndrii Nakryiko
Move bpf_helpers.h, bpf_tracing.h, and bpf_endian.h into libbpf. Move bpf_helper_defs.h generation into libbpf's Makefile. Ensure all those headers are installed along the other libbpf headers. Also, adjust selftests and samples include path to include libbpf now. Signed-off-by: Andrii Nakryiko <andriin@fb.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Song Liu <songliubraving@fb.com> Link: https://lore.kernel.org/bpf/20191008175942.1769476-6-andriin@fb.com
2019-10-05libbpf: Add cscope and tags targets to MakefileToke Høiland-Jørgensen
Using cscope and/or TAGS files for navigating the source code is useful. Add simple targets to the Makefile to generate the index files for both tools. Signed-off-by: Toke Høiland-Jørgensen <toke@redhat.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Tested-by: Andrii Nakryiko <andriin@fb.com> Acked-by: Andrii Nakryiko <andriin@fb.com> Link: https://lore.kernel.org/bpf/20191004153444.1711278-1-toke@redhat.com
2019-09-30libbpf: handle symbol versioning properly for libbpf.aYonghong Song
bcc uses libbpf repo as a submodule. It brings in libbpf source code and builds everything together to produce shared libraries. With latest libbpf, I got the following errors: /bin/ld: libbcc_bpf.so.0.10.0: version node not found for symbol xsk_umem__create@LIBBPF_0.0.2 /bin/ld: failed to set dynamic section sizes: Bad value collect2: error: ld returned 1 exit status make[2]: *** [src/cc/libbcc_bpf.so.0.10.0] Error 1 In xsk.c, we have asm(".symver xsk_umem__create_v0_0_2, xsk_umem__create@LIBBPF_0.0.2"); asm(".symver xsk_umem__create_v0_0_4, xsk_umem__create@@LIBBPF_0.0.4"); The linker thinks the built is for LIBBPF but cannot find proper version LIBBPF_0.0.2/4, so emit errors. I also confirmed that using libbpf.a to produce a shared library also has issues: -bash-4.4$ cat t.c extern void *xsk_umem__create; void * test() { return xsk_umem__create; } -bash-4.4$ gcc -c -fPIC t.c -bash-4.4$ gcc -shared t.o libbpf.a -o t.so /bin/ld: t.so: version node not found for symbol xsk_umem__create@LIBBPF_0.0.2 /bin/ld: failed to set dynamic section sizes: Bad value collect2: error: ld returned 1 exit status -bash-4.4$ Symbol versioning does happens in commonly used libraries, e.g., elfutils and glibc. For static libraries, for a versioned symbol, the old definitions will be ignored, and the symbol will be an alias to the latest definition. For example, glibc sched_setaffinity is versioned. -bash-4.4$ readelf -s /usr/lib64/libc.so.6 | grep sched_setaffinity 756: 000000000013d3d0 13 FUNC GLOBAL DEFAULT 13 sched_setaffinity@GLIBC_2.3.3 757: 00000000000e2e70 455 FUNC GLOBAL DEFAULT 13 sched_setaffinity@@GLIBC_2.3.4 1800: 0000000000000000 0 FILE LOCAL DEFAULT ABS sched_setaffinity.c 4228: 00000000000e2e70 455 FUNC LOCAL DEFAULT 13 __sched_setaffinity_new 4648: 000000000013d3d0 13 FUNC LOCAL DEFAULT 13 __sched_setaffinity_old 7338: 000000000013d3d0 13 FUNC GLOBAL DEFAULT 13 sched_setaffinity@GLIBC_2 7380: 00000000000e2e70 455 FUNC GLOBAL DEFAULT 13 sched_setaffinity@@GLIBC_ -bash-4.4$ For static library, the definition of sched_setaffinity aliases to the new definition. -bash-4.4$ readelf -s /usr/lib64/libc.a | grep sched_setaffinity File: /usr/lib64/libc.a(sched_setaffinity.o) 8: 0000000000000000 455 FUNC GLOBAL DEFAULT 1 __sched_setaffinity_new 12: 0000000000000000 455 FUNC WEAK DEFAULT 1 sched_setaffinity For both elfutils and glibc, additional macros are used to control different handling of symbol versioning w.r.t static and shared libraries. For elfutils, the macro is SYMBOL_VERSIONING (https://sourceware.org/git/?p=elfutils.git;a=blob;f=lib/eu-config.h). For glibc, the macro is SHARED (https://sourceware.org/git/?p=glibc.git;a=blob;f=include/shlib-compat.h;hb=refs/heads/master) This patch used SHARED as the macro name. After this patch, the libbpf.a has -bash-4.4$ readelf -s libbpf.a | grep xsk_umem__create 372: 0000000000017145 1190 FUNC GLOBAL DEFAULT 1 xsk_umem__create_v0_0_4 405: 0000000000017145 1190 FUNC GLOBAL DEFAULT 1 xsk_umem__create 499: 00000000000175eb 103 FUNC GLOBAL DEFAULT 1 xsk_umem__create_v0_0_2 -bash-4.4$ No versioned symbols for xsk_umem__create. The libbpf.a can be used to build a shared library succesfully. -bash-4.4$ cat t.c extern void *xsk_umem__create; void * test() { return xsk_umem__create; } -bash-4.4$ gcc -c -fPIC t.c -bash-4.4$ gcc -shared t.o libbpf.a -o t.so -bash-4.4$ Fixes: 10d30e301732 ("libbpf: add flags to umem config") Cc: Kevin Laatz <kevin.laatz@intel.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Andrii Nakryiko <andriin@fb.com> Acked-by: Andrii Nakryiko <andriin@fb.com> Signed-off-by: Yonghong Song <yhs@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2019-09-30tools: bpf: Use !building_out_of_srctree to determine srctreeShuah Khan
make TARGETS=bpf kselftest fails with: Makefile:127: tools/build/Makefile.include: No such file or directory When the bpf tool make is invoked from tools Makefile, srctree is cleared and the current logic check for srctree equals to empty string to determine srctree location from CURDIR. When the build in invoked from selftests/bpf Makefile, the srctree is set to "." and the same logic used for srctree equals to empty is needed to determine srctree. Check building_out_of_srctree undefined as the condition for both cases to fix "make TARGETS=bpf kselftest" build failure. Signed-off-by: Shuah Khan <skhan@linuxfoundation.org> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Song Liu <songliubraving@fb.com> Link: https://lore.kernel.org/bpf/20190927011344.4695-1-skhan@linuxfoundation.org
2019-08-31libbpf: add flags to umem configKevin Laatz
This patch adds a 'flags' field to the umem_config and umem_reg structs. This will allow for more options to be added for configuring umems. The first use for the flags field is to add a flag for unaligned chunks mode. These flags can either be user-provided or filled with a default. Since we change the size of the xsk_umem_config struct, we need to version the ABI. This patch includes the ABI versioning for xsk_umem__create. The Makefile was also updated to handle multiple function versions in check-abi. Signed-off-by: Kevin Laatz <kevin.laatz@intel.com> Signed-off-by: Ciara Loftus <ciara.loftus@intel.com> Acked-by: Jonathan Lemon <jonathan.lemon@gmail.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2019-08-21libbpf: use LFS (_FILE_OFFSET_BITS) instead of direct mmap2 syscallIvan Khoronzhuk
Drop __NR_mmap2 fork in flavor of LFS, that is _FILE_OFFSET_BITS=64 (glibc & bionic) / LARGEFILE64_SOURCE (for musl) decision. It allows mmap() to use 64bit offset that is passed to mmap2 syscall. As result pgoff is not truncated and no need to use direct access to mmap2 for 32 bits systems. Signed-off-by: Ivan Khoronzhuk <ivan.khoronzhuk@linaro.org> Acked-by: Yonghong Song <yhs@fb.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2019-08-15libbpf: make libbpf.map source of truth for libbpf versionAndrii Nakryiko
Currently libbpf version is specified in 2 places: libbpf.map and Makefile. They easily get out of sync and it's very easy to update one, but forget to update another one. In addition, Github projection of libbpf has to maintain its own version which has to be remembered to be kept in sync manually, which is very error-prone approach. This patch makes libbpf.map a source of truth for libbpf version and uses shell invocation to parse out correct full and major libbpf version to use during build. Now we need to make sure that once new release cycle starts, we need to add (initially) empty section to libbpf.map with correct latest version. This also will make it possible to keep Github projection consistent with kernel sources version of libbpf by adopting similar parsing of version from libbpf.map. v2->v3: - grep -o + sort -rV (Andrey); v1->v2: - eager version vars evaluation (Jakub); - simplified version regex (Andrey); Cc: Andrey Ignatov <rdna@fb.com> Signed-off-by: Andrii Nakryiko <andriin@fb.com> Acked-by: Andrey Ignatov <rdna@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2019-05-28libbpf: add bpf_object__load_xattr() API function to pass log_levelQuentin Monnet
libbpf was recently made aware of the log_level attribute for programs, used to specify the level of information expected to be dumped by the verifier. Function bpf_prog_load_xattr() got support for this log_level parameter. But some applications using libbpf rely on another function to load programs, bpf_object__load(), which does accept any parameter for log level. Create an API function based on bpf_object__load(), but accepting an "attr" object as a parameter. Then add a log_level field to that object, so that applications calling the new bpf_object__load_xattr() can pick the desired log level. v3: - Rewrite commit log. v2: - We are in a new cycle, bump libbpf extraversion number. Signed-off-by: Quentin Monnet <quentin.monnet@netronome.com> Reviewed-by: Jakub Kicinski <jakub.kicinski@netronome.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2019-05-22libbpf: emit diff of mismatched public API, if anyAndrii Nakryiko
It's easy to have a mismatch of "intended to be public" vs really exposed API functions. While Makefile does check for this mismatch, if it actually occurs it's not trivial to determine which functions are accidentally exposed. This patch dumps out a diff showing what's not supposed to be exposed facilitating easier fixing. Signed-off-by: Andrii Nakryiko <andriin@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2019-05-05libbpf: add libbpf_util.h to header install.William Tu
The libbpf_util.h is used by xsk.h, so add it to the install headers. Reported-by: Ben Pfaff <blp@ovn.org> Signed-off-by: William Tu <u9012063@gmail.com> Acked-by: Yonghong Song <yhs@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2019-04-11Merge git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-nextDavid S. Miller
Daniel Borkmann says: ==================== pull-request: bpf-next 2019-04-12 The following pull-request contains BPF updates for your *net-next* tree. The main changes are: 1) Improve BPF verifier scalability for large programs through two optimizations: i) remove verifier states that are not useful in pruning, ii) stop walking parentage chain once first LIVE_READ is seen. Combined gives approx 20x speedup. Increase limits for accepting large programs under root, and add various stress tests, from Alexei. 2) Implement global data support in BPF. This enables static global variables for .data, .rodata and .bss sections to be properly handled which allows for more natural program development. This also opens up the possibility to optimize program workflow by compiling ELFs only once and later only rewriting section data before reload, from Daniel and with test cases and libbpf refactoring from Joe. 3) Add config option to generate BTF type info for vmlinux as part of the kernel build process. DWARF debug info is converted via pahole to BTF. Latter relies on libbpf and makes use of BTF deduplication algorithm which results in 100x savings compared to DWARF data. Resulting .BTF section is typically about 2MB in size, from Andrii. 4) Add BPF verifier support for stack access with variable offset from helpers and add various test cases along with it, from Andrey. 5) Extend bpf_skb_adjust_room() growth BPF helper to mark inner MAC header so that L2 encapsulation can be used for tc tunnels, from Alan. 6) Add support for input __sk_buff context in BPF_PROG_TEST_RUN so that users can define a subset of allowed __sk_buff fields that get fed into the test program, from Stanislav. 7) Add bpf fs multi-dimensional array tests for BTF test suite and fix up various UBSAN warnings in bpftool, from Yonghong. 8) Generate a pkg-config file for libbpf, from Luca. 9) Dump program's BTF id in bpftool, from Prashant. 10) libbpf fix to use smaller BPF log buffer size for AF_XDP's XDP program, from Magnus. 11) kallsyms related fixes for the case when symbols are not present in BPF selftests and samples, from Daniel ==================== Signed-off-by: David S. Miller <davem@davemloft.net>
2019-04-09bpf, libbpf: support global data/bss/rodata sectionsDaniel Borkmann
This work adds BPF loader support for global data sections to libbpf. This allows to write BPF programs in more natural C-like way by being able to define global variables and const data. Back at LPC 2018 [0] we presented a first prototype which implemented support for global data sections by extending BPF syscall where union bpf_attr would get additional memory/size pair for each section passed during prog load in order to later add this base address into the ldimm64 instruction along with the user provided offset when accessing a variable. Consensus from LPC was that for proper upstream support, it would be more desirable to use maps instead of bpf_attr extension as this would allow for introspection of these sections as well as potential live updates of their content. This work follows this path by taking the following steps from loader side: 1) In bpf_object__elf_collect() step we pick up ".data", ".rodata", and ".bss" section information. 2) If present, in bpf_object__init_internal_map() we add maps to the obj's map array that corresponds to each of the present sections. Given section size and access properties can differ, a single entry array map is created with value size that is corresponding to the ELF section size of .data, .bss or .rodata. These internal maps are integrated into the normal map handling of libbpf such that when user traverses all obj maps, they can be differentiated from user-created ones via bpf_map__is_internal(). In later steps when we actually create these maps in the kernel via bpf_object__create_maps(), then for .data and .rodata sections their content is copied into the map through bpf_map_update_elem(). For .bss this is not necessary since array map is already zero-initialized by default. Additionally, for .rodata the map is frozen as read-only after setup, such that neither from program nor syscall side writes would be possible. 3) In bpf_program__collect_reloc() step, we record the corresponding map, insn index, and relocation type for the global data. 4) And last but not least in the actual relocation step in bpf_program__relocate(), we mark the ldimm64 instruction with src_reg = BPF_PSEUDO_MAP_VALUE where in the first imm field the map's file descriptor is stored as similarly done as in BPF_PSEUDO_MAP_FD, and in the second imm field (as ldimm64 is 2-insn wide) we store the access offset into the section. Given these maps have only single element ldimm64's off remains zero in both parts. 5) On kernel side, this special marked BPF_PSEUDO_MAP_VALUE load will then store the actual target address in order to have a 'map-lookup'-free access. That is, the actual map value base address + offset. The destination register in the verifier will then be marked as PTR_TO_MAP_VALUE, containing the fixed offset as reg->off and backing BPF map as reg->map_ptr. Meaning, it's treated as any other normal map value from verification side, only with efficient, direct value access instead of actual call to map lookup helper as in the typical case. Currently, only support for static global variables has been added, and libbpf rejects non-static global variables from loading. This can be lifted until we have proper semantics for how BPF will treat multi-object BPF loads. From BTF side, libbpf will set the value type id of the types corresponding to the ".bss", ".data" and ".rodata" names which LLVM will emit without the object name prefix. The key type will be left as zero, thus making use of the key-less BTF option in array maps. Simple example dump of program using globals vars in each section: # bpftool prog [...] 6784: sched_cls name load_static_dat tag a7e1291567277844 gpl loaded_at 2019-03-11T15:39:34+0000 uid 0 xlated 1776B jited 993B memlock 4096B map_ids 2238,2237,2235,2236,2239,2240 # bpftool map show id 2237 2237: array name test_glo.bss flags 0x0 key 4B value 64B max_entries 1 memlock 4096B # bpftool map show id 2235 2235: array name test_glo.data flags 0x0 key 4B value 64B max_entries 1 memlock 4096B # bpftool map show id 2236 2236: array name test_glo.rodata flags 0x80 key 4B value 96B max_entries 1 memlock 4096B # bpftool prog dump xlated id 6784 int load_static_data(struct __sk_buff * skb): ; int load_static_data(struct __sk_buff *skb) 0: (b7) r6 = 0 ; test_reloc(number, 0, &num0); 1: (63) *(u32 *)(r10 -4) = r6 2: (bf) r2 = r10 ; int load_static_data(struct __sk_buff *skb) 3: (07) r2 += -4 ; test_reloc(number, 0, &num0); 4: (18) r1 = map[id:2238] 6: (18) r3 = map[id:2237][0]+0 <-- direct addr in .bss area 8: (b7) r4 = 0 9: (85) call array_map_update_elem#100464 10: (b7) r1 = 1 ; test_reloc(number, 1, &num1); [...] ; test_reloc(string, 2, str2); 120: (18) r8 = map[id:2237][0]+16 <-- same here at offset +16 122: (18) r1 = map[id:2239] 124: (18) r3 = map[id:2237][0]+16 126: (b7) r4 = 0 127: (85) call array_map_update_elem#100464 128: (b7) r1 = 120 ; str1[5] = 'x'; 129: (73) *(u8 *)(r9 +5) = r1 ; test_reloc(string, 3, str1); 130: (b7) r1 = 3 131: (63) *(u32 *)(r10 -4) = r1 132: (b7) r9 = 3 133: (bf) r2 = r10 ; int load_static_data(struct __sk_buff *skb) 134: (07) r2 += -4 ; test_reloc(string, 3, str1); 135: (18) r1 = map[id:2239] 137: (18) r3 = map[id:2235][0]+16 <-- direct addr in .data area 139: (b7) r4 = 0 140: (85) call array_map_update_elem#100464 141: (b7) r1 = 111 ; __builtin_memcpy(&str2[2], "hello", sizeof("hello")); 142: (73) *(u8 *)(r8 +6) = r1 <-- further access based on .bss data 143: (b7) r1 = 108 144: (73) *(u8 *)(r8 +5) = r1 [...] For Cilium use-case in particular, this enables migrating configuration constants from Cilium daemon's generated header defines into global data sections such that expensive runtime recompilations with LLVM can be avoided altogether. Instead, the ELF file becomes effectively a "template", meaning, it is compiled only once (!) and the Cilium daemon will then rewrite relevant configuration data from the ELF's .data or .rodata sections directly instead of recompiling the program. The updated ELF is then loaded into the kernel and atomically replaces the existing program in the networking datapath. More info in [0]. Based upon recent fix in LLVM, commit c0db6b6bd444 ("[BPF] Don't fail for static variables"). [0] LPC 2018, BPF track, "ELF relocation for static data in BPF", http://vger.kernel.org/lpc-bpf2018.html#session-3 Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Andrii Nakryiko <andriin@fb.com> Acked-by: Martin KaFai Lau <kafai@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2019-03-28tools/bpf: generate pkg-config file for libbpfLuca Boccassi
Generate a libbpf.pc file at build time so that users can rely on pkg-config to find the library, its CFLAGS and LDFLAGS. Signed-off-by: Luca Boccassi <bluca@debian.org> Acked-by: Andrey Ignatov <rdna@fb.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2019-03-28bpf, libbpf: fix quiet install_headersDaniel Borkmann
Both btf.h and xsk.h headers are not installed quietly due to missing '\' for the call to QUIET_INSTALL. Lets fix it. Before: # make install_headers INSTALL headers if [ ! -d '''/usr/local/include/bpf' ]; then install -d -m 755 '''/usr/local/include/bpf'; fi; install btf.h -m 644 '''/usr/local/include/bpf'; if [ ! -d '''/usr/local/include/bpf' ]; then install -d -m 755 '''/usr/local/include/bpf'; fi; install xsk.h -m 644 '''/usr/local/include/bpf'; # ls /usr/local/include/bpf/ bpf.h btf.h libbpf.h xsk.h After: # make install_headers INSTALL headers # ls /usr/local/include/bpf/ bpf.h btf.h libbpf.h xsk.h Fixes: a493f5f9d8c2 ("libbpf: Install btf.h with libbpf") Fixes: 379e2014c95b ("libbpf: add xsk.h to install_headers target") Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Andrii Nakryiko <andriin@fb.com>
generated by cgit (git 2.34.1) at 2025-06-03 04:25:44 +0000