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2022-06-28libbpf: remove prog_info_linear APIsAndrii Nakryiko3-317/+0
Remove prog_info_linear-related APIs previously used by perf. Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/r/20220627211527.2245459-8-andrii@kernel.org Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2022-06-28libbpf: clean up perfbuf APIsAndrii Nakryiko3-112/+18
Remove deprecated perfbuf APIs and clean up opts structs. Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/r/20220627211527.2245459-7-andrii@kernel.org Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2022-06-28libbpf: remove deprecated BTF APIsAndrii Nakryiko5-325/+24
Get rid of deprecated BTF-related APIs. Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/r/20220627211527.2245459-6-andrii@kernel.org Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2022-06-28libbpf: remove deprecated probing APIsAndrii Nakryiko3-132/+5
Get rid of deprecated feature-probing APIs. Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/r/20220627211527.2245459-5-andrii@kernel.org Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2022-06-28libbpf: remove deprecated XDP APIsAndrii Nakryiko3-78/+8
Get rid of deprecated bpf_set_link*() and bpf_get_link*() APIs. Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/r/20220627211527.2245459-4-andrii@kernel.org Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2022-06-28libbpf: remove deprecated low-level APIsAndrii Nakryiko5-374/+4
Drop low-level APIs as well as high-level (and very confusingly named) BPF object loading bpf_prog_load_xattr() and bpf_prog_load_deprecated() APIs. Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/r/20220627211527.2245459-3-andrii@kernel.org Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2022-06-28libbpf: move xsk.{c,h} into selftests/bpfAndrii Nakryiko5-1610/+2
Remove deprecated xsk APIs from libbpf. But given we have selftests relying on this, move those files (with minimal adjustments to make them compilable) under selftests/bpf. We also remove all the removed APIs from libbpf.map, while overall keeping version inheritance chain, as most APIs are backwards compatible so there is no need to reassign them as LIBBPF_1.0.0 versions. Cc: Magnus Karlsson <magnus.karlsson@gmail.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/r/20220627211527.2245459-2-andrii@kernel.org Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2022-06-24bpf: Merge "types_are_compat" logic into relo_core.cDaniel Müller3-71/+83
BPF type compatibility checks (bpf_core_types_are_compat()) are currently duplicated between kernel and user space. That's a historical artifact more than intentional doing and can lead to subtle bugs where one implementation is adjusted but another is forgotten. That happened with the enum64 work, for example, where the libbpf side was changed (commit 23b2a3a8f63a ("libbpf: Add enum64 relocation support")) to use the btf_kind_core_compat() helper function but the kernel side was not (commit 6089fb325cf7 ("bpf: Add btf enum64 support")). This patch addresses both the duplication issue, by merging both implementations and moving them into relo_core.c, and fixes the alluded to kind check (by giving preference to libbpf's already adjusted logic). For discussion of the topic, please refer to: https://lore.kernel.org/bpf/CAADnVQKbWR7oarBdewgOBZUPzryhRYvEbkhyPJQHHuxq=0K1gw@mail.gmail.com/T/#mcc99f4a33ad9a322afaf1b9276fb1f0b7add9665 Changelog: v1 -> v2: - limited libbpf recursion limit to 32 - changed name to __bpf_core_types_are_compat - included warning previously present in libbpf version - merged kernel and user space changes into a single patch Signed-off-by: Daniel Müller <deso@posteo.net> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20220623182934.2582827-1-deso@posteo.net
2022-06-16libbpf: add support for sleepable uprobe programsDelyan Kratunov1-1/+4
Add section mappings for u(ret)probe.s programs. Acked-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Delyan Kratunov <delyank@fb.com> Link: https://lore.kernel.org/r/aedbc3b74f3523f00010a7b0df8f3388cca59f16.1655248076.git.delyank@fb.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2022-06-17libbpf: Fix internal USDT address translation logic for shared librariesAndrii Nakryiko1-60/+63
Perform the same virtual address to file offset translation that libbpf is doing for executable ELF binaries also for shared libraries. Currently libbpf is making a simplifying and sometimes wrong assumption that for shared libraries relative virtual addresses inside ELF are always equal to file offsets. Unfortunately, this is not always the case with LLVM's lld linker, which now by default generates quite more complicated ELF segments layout. E.g., for liburandom_read.so from selftests/bpf, here's an excerpt from readelf output listing ELF segments (a.k.a. program headers): Type Offset VirtAddr PhysAddr FileSiz MemSiz Flg Align PHDR 0x000040 0x0000000000000040 0x0000000000000040 0x0001f8 0x0001f8 R 0x8 LOAD 0x000000 0x0000000000000000 0x0000000000000000 0x0005e4 0x0005e4 R 0x1000 LOAD 0x0005f0 0x00000000000015f0 0x00000000000015f0 0x000160 0x000160 R E 0x1000 LOAD 0x000750 0x0000000000002750 0x0000000000002750 0x000210 0x000210 RW 0x1000 LOAD 0x000960 0x0000000000003960 0x0000000000003960 0x000028 0x000029 RW 0x1000 Compare that to what is generated by GNU ld (or LLVM lld's with extra -znoseparate-code argument which disables this cleverness in the name of file size reduction): Type Offset VirtAddr PhysAddr FileSiz MemSiz Flg Align LOAD 0x000000 0x0000000000000000 0x0000000000000000 0x000550 0x000550 R 0x1000 LOAD 0x001000 0x0000000000001000 0x0000000000001000 0x000131 0x000131 R E 0x1000 LOAD 0x002000 0x0000000000002000 0x0000000000002000 0x0000ac 0x0000ac R 0x1000 LOAD 0x002dc0 0x0000000000003dc0 0x0000000000003dc0 0x000262 0x000268 RW 0x1000 You can see from the first example above that for executable (Flg == "R E") PT_LOAD segment (LOAD #2), Offset doesn't match VirtAddr columns. And it does in the second case (GNU ld output). This is important because all the addresses, including USDT specs, operate in a virtual address space, while kernel is expecting file offsets when performing uprobe attach. So such mismatches have to be properly taken care of and compensated by libbpf, which is what this patch is fixing. Also patch clarifies few function and variable names, as well as updates comments to reflect this important distinction (virtaddr vs file offset) and to ephasize that shared libraries are not all that different from executables in this regard. This patch also changes selftests/bpf Makefile to force urand_read and liburand_read.so to be built with Clang and LLVM's lld (and explicitly request this ELF file size optimization through -znoseparate-code linker parameter) to validate libbpf logic and ensure regressions don't happen in the future. I've bundled these selftests changes together with libbpf changes to keep the above description tied with both libbpf and selftests changes. Fixes: 74cc6311cec9 ("libbpf: Add USDT notes parsing and resolution logic") Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Link: https://lore.kernel.org/bpf/20220616055543.3285835-1-andrii@kernel.org
2022-06-14libbpf: Fix an unsigned < 0 bugYonghong Song1-1/+1
Andrii reported a bug with the following information: 2859 if (enum64_placeholder_id == 0) { 2860 enum64_placeholder_id = btf__add_int(btf, "enum64_placeholder", 1, 0); >>> CID 394804: Control flow issues (NO_EFFECT) >>> This less-than-zero comparison of an unsigned value is never true. "enum64_placeholder_id < 0U". 2861 if (enum64_placeholder_id < 0) 2862 return enum64_placeholder_id; 2863 ... Here enum64_placeholder_id declared as '__u32' so enum64_placeholder_id < 0 is always false. Declare enum64_placeholder_id as 'int' in order to capture the potential error properly. Fixes: f2a625889bb8 ("libbpf: Add enum64 sanitization") Reported-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Yonghong Song <yhs@fb.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Link: https://lore.kernel.org/bpf/20220613054314.1251905-1-yhs@fb.com
2022-06-09libbpf: Fix uprobe symbol file offset calculation logicAndrii Nakryiko1-41/+22
Fix libbpf's bpf_program__attach_uprobe() logic of determining function's *file offset* (which is what kernel is actually expecting) when attaching uprobe/uretprobe by function name. Previously calculation was determining virtual address offset relative to base load address, which (offset) is not always the same as file offset (though very frequently it is which is why this went unnoticed for a while). Fixes: 433966e3ae04 ("libbpf: Support function name-based attach uprobes") Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Cc: Riham Selim <rihams@fb.com> Cc: Alan Maguire <alan.maguire@oracle.com> Link: https://lore.kernel.org/bpf/20220606220143.3796908-1-andrii@kernel.org
2022-06-07libbpf: Add enum64 relocation supportYonghong Song3-20/+48
The enum64 relocation support is added. The bpf local type could be either enum or enum64 and the remote type could be either enum or enum64 too. The all combinations of local enum/enum64 and remote enum/enum64 are supported. Acked-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Yonghong Song <yhs@fb.com> Link: https://lore.kernel.org/r/20220607062647.3721719-1-yhs@fb.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2022-06-07libbpf: Add enum64 support for bpf linkingYonghong Song1-0/+2
Add BTF_KIND_ENUM64 support for bpf linking, which is very similar to BTF_KIND_ENUM. Acked-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Yonghong Song <yhs@fb.com> Link: https://lore.kernel.org/r/20220607062642.3721494-1-yhs@fb.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2022-06-07libbpf: Add enum64 sanitizationYonghong Song3-5/+56
When old kernel does not support enum64 but user space btf contains non-zero enum kflag or enum64, libbpf needs to do proper sanitization so modified btf can be accepted by the kernel. Sanitization for enum kflag can be achieved by clearing the kflag bit. For enum64, the type is replaced with an union of integer member types and the integer member size must be smaller than enum64 size. If such an integer type cannot be found, a new type is created and used for union members. Acked-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Yonghong Song <yhs@fb.com> Link: https://lore.kernel.org/r/20220607062636.3721375-1-yhs@fb.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2022-06-07libbpf: Add enum64 support for btf_dumpYonghong Song2-34/+108
Add enum64 btf dumping support. For long long and unsigned long long dump, suffixes 'LL' and 'ULL' are added to avoid compilation errors in some cases. Acked-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Yonghong Song <yhs@fb.com> Link: https://lore.kernel.org/r/20220607062631.3720526-1-yhs@fb.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2022-06-07libbpf: Add enum64 deduplication supportYonghong Song2-2/+65
Add enum64 deduplication support. BTF_KIND_ENUM64 handling is very similar to BTF_KIND_ENUM. Acked-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Yonghong Song <yhs@fb.com> Link: https://lore.kernel.org/r/20220607062626.3720166-1-yhs@fb.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2022-06-07libbpf: Add enum64 parsing and new enum64 public APIYonghong Song3-0/+117
Add enum64 parsing support and two new enum64 public APIs: btf__add_enum64 btf__add_enum64_value Also add support of signedness for BTF_KIND_ENUM. The BTF_KIND_ENUM API signatures are not changed. The signedness will be changed from unsigned to signed if btf__add_enum_value() finds any negative values. Acked-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Yonghong Song <yhs@fb.com> Link: https://lore.kernel.org/r/20220607062621.3719391-1-yhs@fb.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2022-06-07libbpf: Refactor btf__add_enum() for future code sharingYonghong Song1-15/+21
Refactor btf__add_enum() function to create a separate function btf_add_enum_common() so later the common function can be used to add enum64 btf type. There is no functionality change for this patch. Acked-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Yonghong Song <yhs@fb.com> Link: https://lore.kernel.org/r/20220607062615.3718063-1-yhs@fb.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2022-06-07libbpf: Fix an error in 64bit relocation value computationYonghong Song1-1/+1
Currently, the 64bit relocation value in the instruction is computed as follows: __u64 imm = insn[0].imm + ((__u64)insn[1].imm << 32) Suppose insn[0].imm = -1 (0xffffffff) and insn[1].imm = 1. With the above computation, insn[0].imm will first sign-extend to 64bit -1 (0xffffffffFFFFFFFF) and then add 0x1FFFFFFFF, producing incorrect value 0xFFFFFFFF. The correct value should be 0x1FFFFFFFF. Changing insn[0].imm to __u32 first will prevent 64bit sign extension and fix the issue. Merging high and low 32bit values also changed from '+' to '|' to be consistent with other similar occurences in kernel and libbpf. Acked-by: Andrii Nakryiko <andrii@kernel.org> Acked-by: Dave Marchevsky <davemarchevsky@fb.com> Signed-off-by: Yonghong Song <yhs@fb.com> Link: https://lore.kernel.org/r/20220607062610.3717378-1-yhs@fb.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2022-06-07libbpf: Permit 64bit relocation valueYonghong Song2-24/+29
Currently, the libbpf limits the relocation value to be 32bit since all current relocations have such a limit. But with BTF_KIND_ENUM64 support, the enum value could be 64bit. So let us permit 64bit relocation value in libbpf. Acked-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Yonghong Song <yhs@fb.com> Link: https://lore.kernel.org/r/20220607062605.3716779-1-yhs@fb.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2022-06-03libbpf: Fix is_pow_of_2Yuze Chi3-10/+5
Move the correct definition from linker.c into libbpf_internal.h. Fixes: 0087a681fa8c ("libbpf: Automatically fix up BPF_MAP_TYPE_RINGBUF size, if necessary") Reported-by: Yuze Chi <chiyuze@google.com> Signed-off-by: Yuze Chi <chiyuze@google.com> Signed-off-by: Ian Rogers <irogers@google.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20220603055156.2830463-1-irogers@google.com
2022-06-03libbpf: Fix a couple of typosDaniel Müller3-6/+6
This change fixes a couple of typos that were encountered while studying the source code. Signed-off-by: Daniel Müller <deso@posteo.net> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Acked-by: Song Liu <songliubraving@fb.com> Link: https://lore.kernel.org/bpf/20220601154025.3295035-1-deso@posteo.net
2022-06-02libbpf: Fix determine_ptr_size() guessingDouglas Raillard1-6/+20
One strategy employed by libbpf to guess the pointer size is by finding the size of "unsigned long" type. This is achieved by looking for a type of with the expected name and checking its size. Unfortunately, the C syntax is friendlier to humans than to computers as there is some variety in how such a type can be named. Specifically, gcc and clang do not use the same names for integer types in debug info: - clang uses "unsigned long" - gcc uses "long unsigned int" Lookup all the names for such a type so that libbpf can hope to find the information it wants. Signed-off-by: Douglas Raillard <douglas.raillard@arm.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Acked-by: Yonghong Song <yhs@fb.com> Link: https://lore.kernel.org/bpf/20220524094447.332186-1-douglas.raillard@arm.com
2022-06-02libbpf: Introduce libbpf_bpf_link_type_strDaniel Müller3-0/+31
This change introduces a new function, libbpf_bpf_link_type_str, to the public libbpf API. The function allows users to get a string representation for a bpf_link_type enum variant. Signed-off-by: Daniel Müller <deso@posteo.net> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Acked-by: Quentin Monnet <quentin@isovalent.com> Acked-by: Yonghong Song <yhs@fb.com> Link: https://lore.kernel.org/bpf/20220523230428.3077108-11-deso@posteo.net
2022-06-02libbpf: Introduce libbpf_bpf_attach_type_strDaniel Müller3-0/+64
This change introduces a new function, libbpf_bpf_attach_type_str, to the public libbpf API. The function allows users to get a string representation for a bpf_attach_type variant. Signed-off-by: Daniel Müller <deso@posteo.net> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Acked-by: Quentin Monnet <quentin@isovalent.com> Acked-by: Yonghong Song <yhs@fb.com> Link: https://lore.kernel.org/bpf/20220523230428.3077108-8-deso@posteo.net
2022-06-02libbpf: Introduce libbpf_bpf_map_type_strDaniel Müller3-0/+52
This change introduces a new function, libbpf_bpf_map_type_str, to the public libbpf API. The function allows users to get a string representation for a bpf_map_type enum variant. Signed-off-by: Daniel Müller <deso@posteo.net> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Acked-by: Quentin Monnet <quentin@isovalent.com> Acked-by: Yonghong Song <yhs@fb.com> Link: https://lore.kernel.org/bpf/20220523230428.3077108-5-deso@posteo.net
2022-06-02libbpf: Introduce libbpf_bpf_prog_type_strDaniel Müller3-0/+55
This change introduces a new function, libbpf_bpf_prog_type_str, to the public libbpf API. The function allows users to get a string representation for a bpf_prog_type variant. Signed-off-by: Daniel Müller <deso@posteo.net> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Acked-by: Quentin Monnet <quentin@isovalent.com> Acked-by: Yonghong Song <yhs@fb.com> Link: https://lore.kernel.org/bpf/20220523230428.3077108-2-deso@posteo.net
2022-05-23libbpf: Fix typo in commentJulia Lawall1-1/+1
Spelling mistake (triple letters) in comment. Detected with the help of Coccinelle. Signed-off-by: Julia Lawall <Julia.Lawall@inria.fr> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Acked-by: Daniel Müller <deso@posteo.net> Link: https://lore.kernel.org/bpf/20220521111145.81697-71-Julia.Lawall@inria.fr
2022-05-19libbpf: remove bpf_create_map*() APIsAndrii Nakryiko2-122/+0
To test API removal, get rid of bpf_create_map*() APIs. Perf defines __weak implementation of bpf_map_create() that redirects to old bpf_create_map() and that seems to compile and run fine. Cc: Jiri Olsa <jolsa@kernel.org> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/r/20220518185915.3529475-4-andrii@kernel.org Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2022-05-19libbpf: start 1.0 development cycleAndrii Nakryiko2-2/+6
Start libbpf 1.0 development cycle by adding LIBBPF_1.0.0 section to libbpf.map file and marking all current symbols as local. As we remove all the deprecated APIs we'll populate global list before the final 1.0 release. Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/r/20220518185915.3529475-3-andrii@kernel.org Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2022-05-19libbpf: fix up global symbol counting logicAndrii Nakryiko1-1/+1
Add the same negative ABS filter that we use in VERSIONED_SYM_COUNT to filter out ABS symbols like LIBBPF_0.8.0. Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/r/20220518185915.3529475-2-andrii@kernel.org Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2022-05-16libbpf: fix memory leak in attach_tp for target-less tracepoint programAndrii Nakryiko1-4/+4
Fix sec_name memory leak if user defines target-less SEC("tp"). Fixes: 9af8efc45eb1 ("libbpf: Allow "incomplete" basic tracing SEC() definitions") Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Acked-by: David Vernet <void@manifault.com> Link: https://lore.kernel.org/r/20220516184547.3204674-1-andrii@kernel.org Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2022-05-13libbpf: Add safer high-level wrappers for map operationsAndrii Nakryiko5-0/+229
Add high-level API wrappers for most common and typical BPF map operations that works directly on instances of struct bpf_map * (so you don't have to call bpf_map__fd()) and validate key/value size expectations. These helpers require users to specify key (and value, where appropriate) sizes when performing lookup/update/delete/etc. This forces user to actually think and validate (for themselves) those. This is a good thing as user is expected by kernel to implicitly provide correct key/value buffer sizes and kernel will just read/write necessary amount of data. If it so happens that user doesn't set up buffers correctly (which bit people for per-CPU maps especially) kernel either randomly overwrites stack data or return -EFAULT, depending on user's luck and circumstances. These high-level APIs are meant to prevent such unpleasant and hard to debug bugs. This patch also adds bpf_map_delete_elem_flags() low-level API and requires passing flags to bpf_map__delete_elem() API for consistency across all similar APIs, even though currently kernel doesn't expect any extra flags for BPF_MAP_DELETE_ELEM operation. List of map operations that get these high-level APIs: - bpf_map_lookup_elem; - bpf_map_update_elem; - bpf_map_delete_elem; - bpf_map_lookup_and_delete_elem; - bpf_map_get_next_key. Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Link: https://lore.kernel.org/bpf/20220512220713.2617964-1-andrii@kernel.org
2022-05-11libbpf: Add bpf_program__set_insns functionJiri Olsa3-0/+41
Adding bpf_program__set_insns that allows to set new instructions for a BPF program. This is a very advanced libbpf API and users need to know what they are doing. This should be used from prog_prepare_load_fn callback only. We can have changed instructions after calling prog_prepare_load_fn callback, reloading them. One of the users of this new API will be perf's internal BPF prologue generation. Signed-off-by: Jiri Olsa <jolsa@kernel.org> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20220510074659.2557731-2-jolsa@kernel.org
2022-05-11libbpf: Clean up ringbuf size adjustment implementationAndrii Nakryiko1-4/+2
Drop unused iteration variable, move overflow prevention check into the for loop. Fixes: 0087a681fa8c ("libbpf: Automatically fix up BPF_MAP_TYPE_RINGBUF size, if necessary") Reported-by: Nathan Chancellor <nathan@kernel.org> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Link: https://lore.kernel.org/bpf/20220510185159.754299-1-andrii@kernel.org
2022-05-10libbpf: Assign cookies to links in libbpf.Kui-Feng Lee5-4/+40
Add a cookie field to the attributes of bpf_link_create(). Add bpf_program__attach_trace_opts() to attach a cookie to a link. Signed-off-by: Kui-Feng Lee <kuifeng@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Acked-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20220510205923.3206889-5-kuifeng@fb.com
2022-05-09libbpf: Automatically fix up BPF_MAP_TYPE_RINGBUF size, if necessaryAndrii Nakryiko1-1/+41
Kernel imposes a pretty particular restriction on ringbuf map size. It has to be a power-of-2 multiple of page size. While generally this isn't hard for user to satisfy, sometimes it's impossible to do this declaratively in BPF source code or just plain inconvenient to do at runtime. One such example might be BPF libraries that are supposed to work on different architectures, which might not agree on what the common page size is. Let libbpf find the right size for user instead, if it turns out to not satisfy kernel requirements. If user didn't set size at all, that's most probably a mistake so don't upsize such zero size to one full page, though. Also we need to be careful about not overflowing __u32 max_entries. Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Link: https://lore.kernel.org/bpf/20220509004148.1801791-9-andrii@kernel.org
2022-05-09libbpf: Provide barrier() and barrier_var() in bpf_helpers.hAndrii Nakryiko1-0/+24
Add barrier() and barrier_var() macros into bpf_helpers.h to be used by end users. While a bit advanced and specialized instruments, they are sometimes indispensable. Instead of requiring each user to figure out exact asm volatile incantations for themselves, provide them from bpf_helpers.h. Also remove conflicting definitions from selftests. Some tests rely on barrier_var() definition being nothing, those will still work as libbpf does the #ifndef/#endif guarding for barrier() and barrier_var(), allowing users to redefine them, if necessary. Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Link: https://lore.kernel.org/bpf/20220509004148.1801791-8-andrii@kernel.org
2022-05-09libbpf: Complete field-based CO-RE helpers with field offset helperAndrii Nakryiko1-0/+12
Add bpf_core_field_offset() helper to complete field-based CO-RE helpers. This helper can be useful for feature-detection and for some more advanced cases of field reading (e.g., reading flexible array members). Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Link: https://lore.kernel.org/bpf/20220509004148.1801791-6-andrii@kernel.org
2022-05-09libbpf: Improve usability of field-based CO-RE helpersAndrii Nakryiko1-4/+21
Allow to specify field reference in two ways: - if user has variable of necessary type, they can use variable-based reference (my_var.my_field or my_var_ptr->my_field). This was the only supported syntax up till now. - now, bpf_core_field_exists() and bpf_core_field_size() support also specifying field in a fashion similar to offsetof() macro, by specifying type of the containing struct/union separately and field name separately: bpf_core_field_exists(struct my_type, my_field). This forms is quite often more convenient in practice and it matches type-based CO-RE helpers that support specifying type by its name without requiring any variables. Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Link: https://lore.kernel.org/bpf/20220509004148.1801791-4-andrii@kernel.org
2022-05-09libbpf: Make __kptr and __kptr_ref unconditionally use btf_type_tag() attrAndrii Nakryiko1-5/+0
It will be annoying and surprising for users of __kptr and __kptr_ref if libbpf silently ignores them just because Clang used for compilation didn't support btf_type_tag(). It's much better to get clear compiler error than debug BPF verifier failures later on. Fixes: ef89654f2bc7 ("libbpf: Add kptr type tag macros to bpf_helpers.h") Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Link: https://lore.kernel.org/bpf/20220509004148.1801791-3-andrii@kernel.org
2022-04-28libbpf: Allow to opt-out from creating BPF mapsAndrii Nakryiko3-17/+133
Add bpf_map__set_autocreate() API that allows user to opt-out from libbpf automatically creating BPF map during BPF object load. This is a useful feature when building CO-RE-enabled BPF application that takes advantage of some new-ish BPF map type (e.g., socket-local storage) if kernel supports it, but otherwise uses some alternative way (e.g., extra HASH map). In such case, being able to disable the creation of a map that kernel doesn't support allows to successfully create and load BPF object file with all its other maps and programs. It's still up to user to make sure that no "live" code in any of their BPF programs are referencing such map instance, which can be achieved by guarding such code with CO-RE relocation check or by using .rodata global variables. If user fails to properly guard such code to turn it into "dead code", libbpf will helpfully post-process BPF verifier log and will provide more meaningful error and map name that needs to be guarded properly. As such, instead of: ; value = bpf_map_lookup_elem(&missing_map, &zero); 4: (85) call unknown#2001000000 invalid func unknown#2001000000 ... user will see: ; value = bpf_map_lookup_elem(&missing_map, &zero); 4: <invalid BPF map reference> BPF map 'missing_map' is referenced but wasn't created Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20220428041523.4089853-4-andrii@kernel.org
2022-04-28libbpf: Use libbpf_mem_ensure() when allocating new mapAndrii Nakryiko1-27/+10
Reuse libbpf_mem_ensure() when adding a new map to the list of maps inside bpf_object. It takes care of proper resizing and reallocating of map array and zeroing out newly allocated memory. Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20220428041523.4089853-3-andrii@kernel.org
2022-04-28libbpf: Append "..." in fixed up log if CO-RE spec is truncatedAndrii Nakryiko1-4/+4
Detect CO-RE spec truncation and append "..." to make user aware that there was supposed to be more of the spec there. Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20220428041523.4089853-2-andrii@kernel.org
2022-04-28libbpf: Support target-less SEC() definitions for BTF-backed programsAndrii Nakryiko1-17/+32
Similar to previous patch, support target-less definitions like SEC("fentry"), SEC("freplace"), etc. For such BTF-backed program types it is expected that user will specify BTF target programmatically at runtime using bpf_program__set_attach_target() *before* load phase. If not, libbpf will report this as an error. Aslo use SEC_ATTACH_BTF flag instead of explicitly listing a set of types that are expected to require attach_btf_id. This was an accidental omission during custom SEC() support refactoring. Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Song Liu <songliubraving@fb.com> Link: https://lore.kernel.org/bpf/20220428185349.3799599-3-andrii@kernel.org
2022-04-28libbpf: Allow "incomplete" basic tracing SEC() definitionsAndrii Nakryiko1-18/+51
In a lot of cases the target of kprobe/kretprobe, tracepoint, raw tracepoint, etc BPF program might not be known at the compilation time and will be discovered at runtime. This was always a supported case by libbpf, with APIs like bpf_program__attach_{kprobe,tracepoint,etc}() accepting full target definition, regardless of what was defined in SEC() definition in BPF source code. Unfortunately, up till now libbpf still enforced users to specify at least something for the fake target, e.g., SEC("kprobe/whatever"), which is cumbersome and somewhat misleading. This patch allows target-less SEC() definitions for basic tracing BPF program types: - kprobe/kretprobe; - multi-kprobe/multi-kretprobe; - tracepoints; - raw tracepoints. Such target-less SEC() definitions are meant to specify declaratively proper BPF program type only. Attachment of them will have to be handled programmatically using correct APIs. As such, skeleton's auto-attachment of such BPF programs is skipped and generic bpf_program__attach() will fail, if attempted, due to the lack of enough target information. Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Song Liu <songliubraving@fb.com> Link: https://lore.kernel.org/bpf/20220428185349.3799599-2-andrii@kernel.org
2022-04-26libbpf: Fix up verifier log for unguarded failed CO-RE relosAndrii Nakryiko3-4/+154
Teach libbpf to post-process BPF verifier log on BPF program load failure and detect known error patterns to provide user with more context. Currently there is one such common situation: an "unguarded" failed BPF CO-RE relocation. While failing CO-RE relocation is expected, it is expected to be property guarded in BPF code such that BPF verifier always eliminates BPF instructions corresponding to such failed CO-RE relos as dead code. In cases when user failed to take such precautions, BPF verifier provides the best log it can: 123: (85) call unknown#195896080 invalid func unknown#195896080 Such incomprehensible log error is due to libbpf "poisoning" BPF instruction that corresponds to failed CO-RE relocation by replacing it with invalid `call 0xbad2310` instruction (195896080 == 0xbad2310 reads "bad relo" if you squint hard enough). Luckily, libbpf has all the necessary information to look up CO-RE relocation that failed and provide more human-readable description of what's going on: 5: <invalid CO-RE relocation> failed to resolve CO-RE relocation <byte_off> [6] struct task_struct___bad.fake_field_subprog (0:2 @ offset 8) This hopefully makes it much easier to understand what's wrong with user's BPF program without googling magic constants. This BPF verifier log fixup is setup to be extensible and is going to be used for at least one other upcoming feature of libbpf in follow up patches. Libbpf is parsing lines of BPF verifier log starting from the very end. Currently it processes up to 10 lines of code looking for familiar patterns. This avoids wasting lots of CPU processing huge verifier logs (especially for log_level=2 verbosity level). Actual verification error should normally be found in last few lines, so this should work reliably. If libbpf needs to expand log beyond available log_buf_size, it truncates the end of the verifier log. Given verifier log normally ends with something like: processed 2 insns (limit 1000000) max_states_per_insn 0 total_states 0 peak_states 0 mark_read 0 ... truncating this on program load error isn't too bad (end user can always increase log size, if it needs to get complete log). Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20220426004511.2691730-10-andrii@kernel.org
2022-04-26libbpf: Simplify bpf_core_parse_spec() signatureAndrii Nakryiko1-19/+15
Simplify bpf_core_parse_spec() signature to take struct bpf_core_relo as an input instead of requiring callers to decompose them into type_id, relo, spec_str, etc. This makes using and reusing this helper easier. Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20220426004511.2691730-9-andrii@kernel.org
2022-04-26libbpf: Refactor CO-RE relo human description formatting routineAndrii Nakryiko1-26/+38
Refactor how CO-RE relocation is formatted. Now it dumps human-readable representation, currently used by libbpf in either debug or error message output during CO-RE relocation resolution process, into provided buffer. This approach allows for better reuse of this functionality outside of CO-RE relocation resolution, which we'll use in next patch for providing better error message for BPF verifier rejecting BPF program due to unguarded failed CO-RE relocation. It also gets rid of annoying "stitching" of libbpf_print() calls, which was the only place where we did this. Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20220426004511.2691730-8-andrii@kernel.org
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