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2019-02-08btf: separate btf creation and loadingAndrii Nakryiko1-0/+1
This change splits out previous btf__new functionality of constructing struct btf and loading it into kernel into two: - btf__new() just creates and initializes struct btf - btf__load() attempts to load existing struct btf into kernel btf__free will still close BTF fd, if it was ever loaded successfully into kernel. This change allows users of libbpf to manipulate BTF using its API, without the need to unnecessarily load it into kernel. One of the intended use cases is pahole, which will do DWARF to BTF conversion and then use libbpf to do type deduplication, while then handling ELF sections overwriting and other concerns on its own. Fixes: 2d3feca8c44f ("bpf: btf: print map dump and lookup with btf info") Signed-off-by: Andrii Nakryiko <andriin@fb.com> Acked-by: Song Liu <songliubraving@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2019-02-05tools/bpf: add const qualifier to btf__get_map_kv_tids() map_name parameterYonghong Song1-1/+1
Commit 96408c43447a ("tools/bpf: implement libbpf btf__get_map_kv_tids() API function") added the API function btf__get_map_kv_tids(): btf__get_map_kv_tids(const struct btf *btf, char *map_name, ...) The parameter map_name has type "char *". This is okay inside libbpf library since the map_name is from bpf_map->name which also has type "char *". This will be problematic if the caller for map_name already has attribute "const", e.g., from C++ string.c_str(). It will result in either a warning or an error. /home/yhs/work/bcc/src/cc/btf.cc:166:51: error: invalid conversion from ‘const char*’ to ‘char*’ [-fpermissive] return btf__get_map_kv_tids(btf_, map_name.c_str() This patch added "const" attributes to map_name parameter. Fixes: 96408c43447a ("tools/bpf: implement libbpf btf__get_map_kv_tids() API function") Signed-off-by: Yonghong Song <yhs@fb.com> Acked-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2019-02-05selftests/btf: add initial BTF dedup testsAndrii Nakryiko1-0/+3
This patch sets up a new kind of tests (BTF dedup tests) and tests few aspects of BTF dedup algorithm. More complete set of tests will come in follow up patches. Signed-off-by: Andrii Nakryiko <andriin@fb.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2019-02-05btf: add BTF types deduplication algorithmAndrii Nakryiko1-0/+7
This patch implements BTF types deduplication algorithm. It allows to greatly compress typical output of pahole's DWARF-to-BTF conversion or LLVM's compilation output by detecting and collapsing identical types emitted in isolation per compilation unit. Algorithm also resolves struct/union forward declarations into concrete BTF types representing referenced struct/union. If undesired, this resolution can be disabled through specifying corresponding options. Algorithm itself and its application to Linux kernel's BTF types is described in details at: https://facebookmicrosites.github.io/bpf/blog/2018/11/14/btf-enhancement.html Signed-off-by: Andrii Nakryiko <andriin@fb.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2019-02-04tools/bpf: implement libbpf btf__get_map_kv_tids() API functionYonghong Song1-0/+4
Currently, to get map key/value type id's, the macro BPF_ANNOTATE_KV_PAIR(<map_name>, <key_type>, <value_type>) needs to be defined in the bpf program for the corresponding map. During program/map loading time, the local static function bpf_map_find_btf_info() in libbpf.c is implemented to retrieve the key/value type ids given the map name. The patch refactored function bpf_map_find_btf_info() to create an API btf__get_map_kv_tids() which includes the bulk of implementation for the original function. The API btf__get_map_kv_tids() can be used by bcc, a JIT based bpf compilation system, which uses the same BPF_ANNOTATE_KV_PAIR to record map key/value types. Acked-by: Martin KaFai Lau <kafai@fb.com> Signed-off-by: Yonghong Song <yhs@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2019-02-04tools/bpf: expose functions btf_ext__* as API functionsYonghong Song1-12/+12
The following set of functions, which manipulates .BTF.ext section, are exposed as API functions: . btf_ext__new . btf_ext__free . btf_ext__reloc_func_info . btf_ext__reloc_line_info . btf_ext__func_info_rec_size . btf_ext__line_info_rec_size These functions are useful for JIT based bpf codegen, e.g., bcc, to manipulate in-memory .BTF.ext sections. The signature of function btf_ext__reloc_func_info() is also changed to be the same as its definition in btf.c. Acked-by: Martin KaFai Lau <kafai@fb.com> Signed-off-by: Yonghong Song <yhs@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2019-02-04tools/bpf: move libbpf pr_* debug print functions to headersYonghong Song1-5/+2
A global function libbpf_print, which is invisible outside the shared library, is defined to print based on levels. The pr_warning, pr_info and pr_debug macros are moved into the newly created header common.h. So any .c file including common.h can use these macros directly. Currently btf__new and btf_ext__new API has an argument getting __pr_debug function pointer into btf.c so the debugging information can be printed there. This patch removed this parameter from btf__new and btf_ext__new and directly using pr_debug in btf.c. Another global function libbpf_print_level_available, also invisible outside the shared library, can test whether a particular level debug printing is available or not. It is used in btf.c to test whether DEBUG level debug printing is availabl or not, based on which the log buffer will be allocated when loading btf to the kernel. Signed-off-by: Yonghong Song <yhs@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2018-12-09bpf: libbpf: Add btf_line_info support to libbpfMartin KaFai Lau1-1/+9
This patch adds bpf_line_info support to libbpf: 1) Parsing the line_info sec from ".BTF.ext" 2) Relocating the line_info. If the main prog *_info relocation fails, it will ignore the remaining subprog line_info and continue. If the subprog *_info relocation fails, it will bail out. 3) BPF_PROG_LOAD a prog with line_info Signed-off-by: Martin KaFai Lau <kafai@fb.com> Acked-by: Yonghong Song <yhs@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2018-12-09bpf: libbpf: Refactor and bug fix on the bpf_func_info loading logicMartin KaFai Lau1-13/+4
This patch refactor and fix a bug in the libbpf's bpf_func_info loading logic. The bug fix and refactoring are targeting the same commit 2993e0515bb4 ("tools/bpf: add support to read .BTF.ext sections") which is in the bpf-next branch. 1) In bpf_load_program_xattr(), it should retry when errno == E2BIG regardless of log_buf and log_buf_sz. This patch fixes it. 2) btf_ext__reloc_init() and btf_ext__reloc() are essentially the same except btf_ext__reloc_init() always has insns_cnt == 0. Hence, btf_ext__reloc_init() is removed. btf_ext__reloc() is also renamed to btf_ext__reloc_func_info() to get ready for the line_info support in the next patch. 3) Consolidate func_info section logic from "btf_ext_parse_hdr()", "btf_ext_validate_func_info()" and "btf_ext__new()" to a new function "btf_ext_copy_func_info()" such that similar logic can be reused by the later libbpf's line_info patch. 4) The next line_info patch will store line_info_cnt instead of line_info_len in the bpf_program because the kernel is taking line_info_cnt also. It will save a few "len" to "cnt" conversions and will also save some function args. Hence, this patch also makes bpf_program to store func_info_cnt instead of func_info_len. 5) btf_ext depends on btf. e.g. the func_info's type_id in ".BTF.ext" is not useful when ".BTF" is absent. This patch only init the obj->btf_ext pointer after it has successfully init the obj->btf pointer. This can avoid always checking "obj->btf && obj->btf_ext" together for accessing ".BTF.ext". Checking "obj->btf_ext" alone will do. 6) Move "struct btf_sec_func_info" from btf.h to btf.c. There is no external usage outside btf.c. Fixes: 2993e0515bb4 ("tools/bpf: add support to read .BTF.ext sections") Signed-off-by: Martin KaFai Lau <kafai@fb.com> Acked-by: Yonghong Song <yhs@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2018-11-26libbpf: Name changing for btf_get_from_idMartin KaFai Lau1-1/+1
s/btf_get_from_id/btf__get_from_id/ to restore the API naming convention. Signed-off-by: Martin KaFai Lau <kafai@fb.com> Signed-off-by: Andrey Ignatov <rdna@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2018-11-21libbpf: make sure bpf headers are c++ include-ableStanislav Fomichev1-0/+8
Wrap headers in extern "C", to turn off C++ mangling. This simplifies including libbpf in c++ and linking against it. v2 changes: * do the same for btf.h v3 changes: * test_libbpf.cpp to test for possible future c++ breakages Signed-off-by: Stanislav Fomichev <sdf@google.com> Acked-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2018-11-20tools/bpf: refactor to implement btf_get_from_id() in lib/bpfYonghong Song1-0/+1
The function get_btf() is implemented in tools/bpf/bpftool/map.c to get a btf structure given a map_info. This patch refactored this function to be function btf_get_from_id() in tools/lib/bpf so that it can be used later. Signed-off-by: Yonghong Song <yhs@fb.com> Signed-off-by: Martin KaFai Lau <kafai@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2018-11-20tools/bpf: add support to read .BTF.ext sectionsYonghong Song1-0/+50
The .BTF section is already available to encode types. These types can be used for map pretty print. The whole .BTF will be passed to the kernel as well for which kernel can verify and return to the user space for pretty print etc. The llvm patch at https://reviews.llvm.org/D53736 will generate .BTF section and one more section .BTF.ext. The .BTF.ext section encodes function type information and line information. Note that this patch set only supports function type info. The functionality is implemented in libbpf. The .BTF section can be directly loaded into the kernel, and the .BTF.ext section cannot. The loader may need to do some relocation and merging, similar to merging multiple code sections, before loading into the kernel. Signed-off-by: Yonghong Song <yhs@fb.com> Signed-off-by: Martin KaFai Lau <kafai@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2018-10-16libbpf: Per-symbol visibility for DSOAndrey Ignatov1-8/+14
Make global symbols in libbpf DSO hidden by default with -fvisibility=hidden and export symbols that are part of ABI explicitly with __attribute__((visibility("default"))). This is common practice that should prevent from accidentally exporting a symbol, that is not supposed to be a part of ABI what, in turn, improves both libbpf developer- and user-experiences. See [1] for more details. Export control becomes more important since more and more projects use libbpf. The patch doesn't export a bunch of netlink related functions since as agreed in [2] they'll be reworked. That doesn't break bpftool since bpftool links libbpf statically. [1] https://www.akkadia.org/drepper/dsohowto.pdf (2.2 Export Control) [2] https://www.mail-archive.com/netdev@vger.kernel.org/msg251434.html Signed-off-by: Andrey Ignatov <rdna@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2018-10-08libbpf: relicense libbpf as LGPL-2.1 OR BSD-2-ClauseAlexei Starovoitov1-1/+1
libbpf is maturing as a library and gaining features that no other bpf libraries support (BPF Type Format, bpf to bpf calls, etc) Many Apache2 licensed projects (like bcc, bpftrace, gobpf, cilium, etc) would like to use libbpf, but cannot do this yet, since Apache Foundation explicitly states that LGPL is incompatible with Apache2. Hence let's relicense libbpf as dual license LGPL-2.1 or BSD-2-Clause, since BSD-2 is compatible with Apache2. Dual LGPL or Apache2 is invalid combination. Fix license mistake in Makefile as well. Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Andrey Ignatov <rdna@fb.com> Acked-by: Arnaldo Carvalho de Melo <acme@kernel.org> Acked-by: Björn Töpel <bjorn.topel@intel.com> Acked-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: David Beckett <david.beckett@netronome.com> Acked-by: Jakub Kicinski <jakub.kicinski@netronome.com> Acked-by: Joe Stringer <joe@ovn.org> Acked-by: John Fastabend <john.fastabend@gmail.com> Acked-by: Martin KaFai Lau <kafai@fb.com> Acked-by: Quentin Monnet <quentin.monnet@netronome.com> Acked-by: Thomas Graf <tgraf@suug.ch> Acked-by: Roman Gushchin <guro@fb.com> Acked-by: Wang Nan <wangnan0@huawei.com> Acked-by: Yonghong Song <yhs@fb.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2018-10-04libbpf: Make include guards consistentAndrey Ignatov1-3/+3
Rename include guards to have consistent names "__LIBBPF_<header_name>". Signed-off-by: Andrey Ignatov <rdna@fb.com> Acked-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2018-08-11Merge ra.kernel.org:/pub/scm/linux/kernel/git/davem/netDavid S. Miller1-1/+1
2018-08-06bpf: btf: Change tools/lib/bpf/btf to LGPLMartin KaFai Lau1-1/+1
This patch changes the tools/lib/bpf/btf.[ch] to LGPL which is inline with libbpf also. Signed-off-by: Martin KaFai Lau <kafai@fb.com> Acked-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2018-08-02tools: bpf: fix BTF code added twice to different treesJakub Kicinski1-1/+0
commit 38d5d3b3d5db ("bpf: Introduce BPF_ANNOTATE_KV_PAIR") added to the bpf and net trees what commit 92b57121ca79 ("bpf: btf: export btf types and name by offset from lib") has already added to bpf-next/net-next, but in slightly different location. Remove the duplicates (to fix build of libbpf). Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-08-02Merge ra.kernel.org:/pub/scm/linux/kernel/git/davem/netDavid S. Miller1-4/+6
The BTF conflicts were simple overlapping changes. The virtio_net conflict was an overlap of a fix of statistics counter, happening alongisde a move over to a bonafide statistics structure rather than counting value on the stack. Signed-off-by: David S. Miller <davem@davemloft.net>
2018-07-25bpf: Introduce BPF_ANNOTATE_KV_PAIRMartin KaFai Lau1-0/+2
This patch introduces BPF_ANNOTATE_KV_PAIR to signal the bpf loader about the btf key_type and value_type of a bpf map. Please refer to the changes in test_btf_haskv.c for its usage. Both iproute2 and libbpf loader will then have the same convention to find out the map's btf_key_type_id and btf_value_type_id from a map's name. Fixes: 8a138aed4a80 ("bpf: btf: Add BTF support to libbpf") Suggested-by: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: Martin KaFai Lau <kafai@fb.com> Acked-by: Yonghong Song <yhs@fb.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2018-07-25bpf: Replace [u]int32_t and [u]int64_t in libbpfMartin KaFai Lau1-4/+4
This patch replaces [u]int32_t and [u]int64_t usage with __[su]32 and __[su]64. The same change goes for [u]int16_t and [u]int8_t. Fixes: 8a138aed4a80 ("bpf: btf: Add BTF support to libbpf") Signed-off-by: Martin KaFai Lau <kafai@fb.com> Acked-by: Yonghong Song <yhs@fb.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2018-07-14bpf: btf: export btf types and name by offset from libOkash Khawaja1-0/+3
This patch introduces btf__resolve_type() function and exports two existing functions from libbpf. btf__resolve_type follows modifier types like const and typedef until it hits a type which actually takes up memory, and then returns it. This function follows similar pattern to btf__resolve_size but instead of computing size, it just returns the type. These functions will be used in the followig patch which parses information inside array of `struct btf_type *`. btf_name_by_offset is used for printing variable names. Signed-off-by: Okash Khawaja <osk@fb.com> Acked-by: Martin KaFai Lau <kafai@fb.com> Acked-by: Song Liu <songliubraving@fb.com> Reviewed-by: Jakub Kicinski <jakub.kicinski@netronome.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2018-04-19bpf: btf: Add BTF support to libbpfMartin KaFai Lau1-0/+22
If the ".BTF" elf section exists, libbpf will try to create a btf_fd (through BPF_BTF_LOAD). If that fails, it will still continue loading the bpf prog/map without the BTF. If the bpf_object has a BTF loaded, it will create a map with the btf_fd. libbpf will try to figure out the btf_key_id and btf_value_id of a map by finding the BTF type with name "<map_name>_key" and "<map_name>_value". If they cannot be found, it will continue without using the BTF. Signed-off-by: Martin KaFai Lau <kafai@fb.com> Acked-by: Alexei Starovoitov <ast@fb.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>