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25703adf |
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01-Mar-2024 |
Chen Shen <peterchenshen@gmail.com> |
libbpf: Correct debug message in btf__load_vmlinux_btf In the function btf__load_vmlinux_btf, the debug message incorrectly refers to 'path' instead of 'sysfs_btf_path'. Signed-off-by: Chen Shen <peterchenshen@gmail.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Yonghong Song <yonghong.song@linux.dev> Link: https://lore.kernel.org/bpf/20240302062218.3587-1-peterchenshen@gmail.com
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b9551da8 |
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01-Feb-2024 |
Andrii Nakryiko <andrii@kernel.org> |
libbpf: Add missed btf_ext__raw_data() API Another API that was declared in libbpf.map but actual implementation was missing. btf_ext__get_raw_data() was intended as a discouraged alias to consistently-named btf_ext__raw_data(), so make this an actuality. Fixes: 20eccf29e297 ("libbpf: hide and discourage inconsistently named getters") Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Eduard Zingerman <eddyz87@gmail.com> Link: https://lore.kernel.org/bpf/20240201172027.604869-5-andrii@kernel.org
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c81a8ab1 |
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01-Feb-2024 |
Andrii Nakryiko <andrii@kernel.org> |
libbpf: Add btf__new_split() API that was declared but not implemented Seems like original commit adding split BTF support intended to add btf__new_split() API, and even declared it in libbpf.map, but never added (trivial) implementation. Fix this. Fixes: ba451366bf44 ("libbpf: Implement basic split BTF support") Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Eduard Zingerman <eddyz87@gmail.com> Link: https://lore.kernel.org/bpf/20240201172027.604869-4-andrii@kernel.org
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f2e4040c |
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25-Jan-2024 |
Ian Rogers <irogers@google.com> |
libbpf: Add some details for BTF parsing failures As CONFIG_DEBUG_INFO_BTF is default off the existing "failed to find valid kernel BTF" message makes diagnosing the kernel build issue somewhat cryptic. Add a little more detail with the hope of helping users. Before: ``` libbpf: failed to find valid kernel BTF libbpf: Error loading vmlinux BTF: -3 ``` After not accessible: ``` libbpf: kernel BTF is missing at '/sys/kernel/btf/vmlinux', was CONFIG_DEBUG_INFO_BTF enabled? libbpf: failed to find valid kernel BTF libbpf: Error loading vmlinux BTF: -3 ``` After not readable: ``` libbpf: failed to read kernel BTF from (/sys/kernel/btf/vmlinux): -1 ``` Closes: https://lore.kernel.org/bpf/CAP-5=fU+DN_+Y=Y4gtELUsJxKNDDCOvJzPHvjUVaUoeFAzNnig@mail.gmail.com/ Signed-off-by: Ian Rogers <irogers@google.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20240125231840.1647951-1-irogers@google.com
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6b434b61 |
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23-Jan-2024 |
Andrii Nakryiko <andrii@kernel.org> |
libbpf: Wire up BPF token support at BPF object level Add BPF token support to BPF object-level functionality. BPF token is supported by BPF object logic either as an explicitly provided BPF token from outside (through BPF FS path), or implicitly (unless prevented through bpf_object_open_opts). Implicit mode is assumed to be the most common one for user namespaced unprivileged workloads. The assumption is that privileged container manager sets up default BPF FS mount point at /sys/fs/bpf with BPF token delegation options (delegate_{cmds,maps,progs,attachs} mount options). BPF object during loading will attempt to create BPF token from /sys/fs/bpf location, and pass it for all relevant operations (currently, map creation, BTF load, and program load). In this implicit mode, if BPF token creation fails due to whatever reason (BPF FS is not mounted, or kernel doesn't support BPF token, etc), this is not considered an error. BPF object loading sequence will proceed with no BPF token. In explicit BPF token mode, user provides explicitly custom BPF FS mount point path. In such case, BPF object will attempt to create BPF token from provided BPF FS location. If BPF token creation fails, that is considered a critical error and BPF object load fails with an error. Libbpf provides a way to disable implicit BPF token creation, if it causes any troubles (BPF token is designed to be completely optional and shouldn't cause any problems even if provided, but in the world of BPF LSM, custom security logic can be installed that might change outcome depending on the presence of BPF token). To disable libbpf's default BPF token creation behavior user should provide either invalid BPF token FD (negative), or empty bpf_token_path option. BPF token presence can influence libbpf's feature probing, so if BPF object has associated BPF token, feature probing is instructed to use BPF object-specific feature detection cache and token FD. Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20240124022127.2379740-26-andrii@kernel.org
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d17aff80 |
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19-Dec-2023 |
Andrii Nakryiko <andrii@kernel.org> |
Revert BPF token-related functionality This patch includes the following revert (one conflicting BPF FS patch and three token patch sets, represented by merge commits): - revert 0f5d5454c723 "Merge branch 'bpf-fs-mount-options-parsing-follow-ups'"; - revert 750e785796bb "bpf: Support uid and gid when mounting bpffs"; - revert 733763285acf "Merge branch 'bpf-token-support-in-libbpf-s-bpf-object'"; - revert c35919dcce28 "Merge branch 'bpf-token-and-bpf-fs-based-delegation'". Link: https://lore.kernel.org/bpf/CAHk-=wg7JuFYwGy=GOMbRCtOL+jwSQsdUaBsRWkDVYbxipbM5A@mail.gmail.com Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
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#
1d0dd6ea |
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13-Dec-2023 |
Andrii Nakryiko <andrii@kernel.org> |
libbpf: wire up BPF token support at BPF object level Add BPF token support to BPF object-level functionality. BPF token is supported by BPF object logic either as an explicitly provided BPF token from outside (through BPF FS path or explicit BPF token FD), or implicitly (unless prevented through bpf_object_open_opts). Implicit mode is assumed to be the most common one for user namespaced unprivileged workloads. The assumption is that privileged container manager sets up default BPF FS mount point at /sys/fs/bpf with BPF token delegation options (delegate_{cmds,maps,progs,attachs} mount options). BPF object during loading will attempt to create BPF token from /sys/fs/bpf location, and pass it for all relevant operations (currently, map creation, BTF load, and program load). In this implicit mode, if BPF token creation fails due to whatever reason (BPF FS is not mounted, or kernel doesn't support BPF token, etc), this is not considered an error. BPF object loading sequence will proceed with no BPF token. In explicit BPF token mode, user provides explicitly either custom BPF FS mount point path or creates BPF token on their own and just passes token FD directly. In such case, BPF object will either dup() token FD (to not require caller to hold onto it for entire duration of BPF object lifetime) or will attempt to create BPF token from provided BPF FS location. If BPF token creation fails, that is considered a critical error and BPF object load fails with an error. Libbpf provides a way to disable implicit BPF token creation, if it causes any troubles (BPF token is designed to be completely optional and shouldn't cause any problems even if provided, but in the world of BPF LSM, custom security logic can be installed that might change outcome dependin on the presence of BPF token). To disable libbpf's default BPF token creation behavior user should provide either invalid BPF token FD (negative), or empty bpf_token_path option. BPF token presence can influence libbpf's feature probing, so if BPF object has associated BPF token, feature probing is instructed to use BPF object-specific feature detection cache and token FD. Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/r/20231213190842.3844987-7-andrii@kernel.org Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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3903802b |
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25-Aug-2023 |
Andrii Nakryiko <andrii@kernel.org> |
libbpf: Add basic BTF sanity validation Implement a simple and straightforward BTF sanity check when parsing BTF data. Right now it's very basic and just validates that all the string offsets and type IDs are within valid range. For FUNC we also check that it points to FUNC_PROTO kinds. Even with such simple checks it fixes a bunch of crashes found by OSS fuzzer ([0]-[5]) and will allow fuzzer to make further progress. Some other invariants will be checked in follow up patches (like ensuring there is no infinite type loops), but this seems like a good start already. Adding FUNC -> FUNC_PROTO check revealed that one of selftests has a problem with FUNC pointing to VAR instead, so fix it up in the same commit. [0] https://github.com/libbpf/libbpf/issues/482 [1] https://github.com/libbpf/libbpf/issues/483 [2] https://github.com/libbpf/libbpf/issues/485 [3] https://github.com/libbpf/libbpf/issues/613 [4] https://github.com/libbpf/libbpf/issues/618 [5] https://github.com/libbpf/libbpf/issues/619 Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Reviewed-by: Alan Maguire <alan.maguire@oracle.com> Reviewed-by: Song Liu <song@kernel.org> Closes: https://github.com/libbpf/libbpf/issues/617 Link: https://lore.kernel.org/bpf/20230825202152.1813394-1-andrii@kernel.org
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59842c54 |
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25-May-2023 |
Andrii Nakryiko <andrii@kernel.org> |
libbpf: Ensure libbpf always opens files with O_CLOEXEC Make sure that libbpf code always gets FD with O_CLOEXEC flag set, regardless if file is open through open() or fopen(). For the latter this means to add "e" to mode string, which is supported since pretty ancient glibc v2.7. Also drop the outdated TODO comment in usdt.c, which was already completed. Suggested-by: Lennart Poettering <lennart@poettering.net> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Link: https://lore.kernel.org/bpf/20230525221311.2136408-1-andrii@kernel.org
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7832d06b |
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01-Mar-2023 |
Viktor Malik <vmalik@redhat.com> |
libbpf: Remove several dead assignments Clang Static Analyzer (scan-build) reports several dead assignments in libbpf where the assigned value is unconditionally overridden by another value before it is read. Remove these assignments. Signed-off-by: Viktor Malik <vmalik@redhat.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/5503d18966583e55158471ebbb2f67374b11bf5e.1677658777.git.vmalik@redhat.com
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629dfc66 |
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14-Feb-2023 |
Ilya Leoshkevich <iii@linux.ibm.com> |
libbpf: Use bpf_{btf,link,map,prog}_get_info_by_fd() Use the new type-safe wrappers around bpf_obj_get_info_by_fd(). Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20230214231221.249277-3-iii@linux.ibm.com
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acd3b776 |
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31-Dec-2022 |
Changbin Du <changbin.du@intel.com> |
libbpf: Return -ENODATA for missing btf section As discussed before, return -ENODATA (No data available) would be more meaningful than ENOENT (No such file or directory). Suggested-by: Leo Yan <leo.yan@linaro.org> Signed-off-by: Changbin Du <changbin.du@gmail.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20221231151436.6541-1-changbin.du@gmail.com
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e6b4e1d7 |
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17-Dec-2022 |
Changbin Du <changbin.du@intel.com> |
libbpf: Show error info about missing ".BTF" section Show the real problem instead of just saying "No such file or directory". Now will print below info: libbpf: failed to find '.BTF' ELF section in /home/changbin/work/linux/vmlinux Error: failed to load BTF from /home/changbin/work/linux/vmlinux: No such file or directory Signed-off-by: Changbin Du <changbin.du@gmail.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20221217223509.88254-2-changbin.du@gmail.com
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25a4481b |
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12-Dec-2022 |
Andrii Nakryiko <andrii@kernel.org> |
libbpf: Fix btf__align_of() by taking into account field offsets btf__align_of() is supposed to be return alignment requirement of a requested BTF type. For STRUCT/UNION it doesn't always return correct value, because it calculates alignment only based on field types. But for packed structs this is not enough, we need to also check field offsets and struct size. If field offset isn't aligned according to field type's natural alignment, then struct must be packed. Similarly, if struct size is not a multiple of struct's natural alignment, then struct must be packed as well. This patch fixes this issue precisely by additionally checking these conditions. Fixes: 3d208f4ca111 ("libbpf: Expose btf__align_of() API") Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Link: https://lore.kernel.org/bpf/20221212211505.558851-5-andrii@kernel.org
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c7694ac3 |
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13-Nov-2022 |
Kang Minchul <tegongkang@gmail.com> |
libbpf: checkpatch: Fixed code alignments in btf.c Fixed some checkpatch issues in btf.c Signed-off-by: Kang Minchul <tegongkang@gmail.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Acked-by: Stanislav Fomichev <sdf@google.com> Link: https://lore.kernel.org/bpf/20221113190648.38556-2-tegongkang@gmail.com
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082108fd |
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09-Nov-2022 |
Eduard Zingerman <eddyz87@gmail.com> |
libbpf: Resolve unambigous forward declarations Resolve forward declarations that don't take part in type graphs comparisons if declaration name is unambiguous. Example: CU #1: struct foo; // standalone forward declaration struct foo *some_global; CU #2: struct foo { int x; }; struct foo *another_global; The `struct foo` from CU #1 is not a part of any definition that is compared against another definition while `btf_dedup_struct_types` processes structural types. The the BTF after `btf_dedup_struct_types` the BTF looks as follows: [1] STRUCT 'foo' size=4 vlen=1 ... [2] INT 'int' size=4 ... [3] PTR '(anon)' type_id=1 [4] FWD 'foo' fwd_kind=struct [5] PTR '(anon)' type_id=4 This commit adds a new pass `btf_dedup_resolve_fwds`, that maps such forward declarations to structs or unions with identical name in case if the name is not ambiguous. The pass is positioned before `btf_dedup_ref_types` so that types [3] and [5] could be merged as a same type after [1] and [4] are merged. The final result for the example above looks as follows: [1] STRUCT 'foo' size=4 vlen=1 'x' type_id=2 bits_offset=0 [2] INT 'int' size=4 bits_offset=0 nr_bits=32 encoding=SIGNED [3] PTR '(anon)' type_id=1 For defconfig kernel with BTF enabled this removes 63 forward declarations. Examples of removed declarations: `pt_regs`, `in6_addr`. The running time of `btf__dedup` function is increased by about 3%. Signed-off-by: Eduard Zingerman <eddyz87@gmail.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Reviewed-by: Alan Maguire <alan.maguire@oracle.com> Acked-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20221109142611.879983-3-eddyz87@gmail.com
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c302378b |
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09-Nov-2022 |
Eduard Zingerman <eddyz87@gmail.com> |
libbpf: Hashmap interface update to allow both long and void* keys/values An update for libbpf's hashmap interface from void* -> void* to a polymorphic one, allowing both long and void* keys and values. This simplifies many use cases in libbpf as hashmaps there are mostly integer to integer. Perf copies hashmap implementation from libbpf and has to be updated as well. Changes to libbpf, selftests/bpf and perf are packed as a single commit to avoid compilation issues with any future bisect. Polymorphic interface is acheived by hiding hashmap interface functions behind auxiliary macros that take care of necessary type casts, for example: #define hashmap_cast_ptr(p) \ ({ \ _Static_assert((p) == NULL || sizeof(*(p)) == sizeof(long),\ #p " pointee should be a long-sized integer or a pointer"); \ (long *)(p); \ }) bool hashmap_find(const struct hashmap *map, long key, long *value); #define hashmap__find(map, key, value) \ hashmap_find((map), (long)(key), hashmap_cast_ptr(value)) - hashmap__find macro casts key and value parameters to long and long* respectively - hashmap_cast_ptr ensures that value pointer points to a memory of appropriate size. This hack was suggested by Andrii Nakryiko in [1]. This is a follow up for [2]. [1] https://lore.kernel.org/bpf/CAEf4BzZ8KFneEJxFAaNCCFPGqp20hSpS2aCj76uRk3-qZUH5xg@mail.gmail.com/ [2] https://lore.kernel.org/bpf/af1facf9-7bc8-8a3d-0db4-7b3f333589a2@meta.com/T/#m65b28f1d6d969fcd318b556db6a3ad499a42607d Signed-off-by: Eduard Zingerman <eddyz87@gmail.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20221109142611.879983-2-eddyz87@gmail.com
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de048b6e |
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01-Nov-2022 |
Eduard Zingerman <eddyz87@gmail.com> |
libbpf: Resolve enum fwd as full enum64 and vice versa Changes de-duplication logic for enums in the following way: - update btf_hash_enum to ignore size and kind fields to get ENUM and ENUM64 types in a same hash bucket; - update btf_compat_enum to consider enum fwd to be compatible with full enum64 (and vice versa); This allows BTF de-duplication in the following case: // CU #1 enum foo; struct s { enum foo *a; } *x; // CU #2 enum foo { x = 0xfffffffff // big enough to force enum64 }; struct s { enum foo *a; } *y; De-duplicated BTF prior to this commit: [1] ENUM64 'foo' encoding=UNSIGNED size=8 vlen=1 'x' val=68719476735ULL [2] INT 'long unsigned int' size=8 bits_offset=0 nr_bits=64 encoding=(none) [3] STRUCT 's' size=8 vlen=1 'a' type_id=4 bits_offset=0 [4] PTR '(anon)' type_id=1 [5] PTR '(anon)' type_id=3 [6] STRUCT 's' size=8 vlen=1 'a' type_id=8 bits_offset=0 [7] ENUM 'foo' encoding=UNSIGNED size=4 vlen=0 [8] PTR '(anon)' type_id=7 [9] PTR '(anon)' type_id=6 De-duplicated BTF after this commit: [1] ENUM64 'foo' encoding=UNSIGNED size=8 vlen=1 'x' val=68719476735ULL [2] INT 'long unsigned int' size=8 bits_offset=0 nr_bits=64 encoding=(none) [3] STRUCT 's' size=8 vlen=1 'a' type_id=4 bits_offset=0 [4] PTR '(anon)' type_id=1 [5] PTR '(anon)' type_id=3 Enum forward declarations in C do not provide information about enumeration values range. Thus the `btf_type->size` field is meaningless for forward enum declarations. In fact, GCC does not encode size in DWARF for forward enum declarations (but dwarves sets enumeration size to a default value of `sizeof(int) * 8` when size is not specified see dwarf_loader.c:die__create_new_enumeration). Signed-off-by: Eduard Zingerman <eddyz87@gmail.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20221101235413.1824260-1-eddyz87@gmail.com
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f3c51fe0 |
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24-Oct-2022 |
Alan Maguire <alan.maguire@oracle.com> |
libbpf: Btf dedup identical struct test needs check for nested structs/arrays When examining module BTF, it is common to see core kernel structures such as sk_buff, net_device duplicated in the module. After adding debug messaging to BTF it turned out that much of the problem was down to the identical struct test failing during deduplication; sometimes the compiler adds identical structs. However it turns out sometimes that type ids of identical struct members can also differ, even when the containing structs are still identical. To take an example, for struct sk_buff, debug messaging revealed that the identical struct matching was failing for the anon struct "headers"; specifically for the first field: __u8 __pkt_type_offset[0]; /* 128 0 */ Looking at the code in BTF deduplication, we have code that guards against the possibility of identical struct definitions, down to type ids, and identical array definitions. However in this case we have a struct which is being defined twice but does not have identical type ids since each duplicate struct has separate type ids for the above array member. A similar problem (though not observed) could occur for struct-in-struct. The solution is to make the "identical struct" test check members not just for matching ids, but to also check if they in turn are identical structs or arrays. The results of doing this are quite dramatic (for some modules at least); I see the number of type ids drop from around 10000 to just over 1000 in one module for example. For testing use latest pahole or apply [1], otherwise dedups can fail for the reasons described there. Also fix return type of btf_dedup_identical_arrays() as suggested by Andrii to match boolean return type used elsewhere. Fixes: efdd3eb8015e ("libbpf: Accommodate DWARF/compiler bug with duplicated structs") Signed-off-by: Alan Maguire <alan.maguire@oracle.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/1666622309-22289-1-git-send-email-alan.maguire@oracle.com [1] https://lore.kernel.org/bpf/1666364523-9648-1-git-send-email-alan.maguire
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6a4ab886 |
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25-Sep-2022 |
Jon Doron <jond@wiz.io> |
libbpf: Fix the case of running as non-root with capabilities When running rootless with special capabilities like: FOWNER / DAC_OVERRIDE / DAC_READ_SEARCH The "access" API will not make the proper check if there is really access to a file or not. >From the access man page: " The check is done using the calling process's real UID and GID, rather than the effective IDs as is done when actually attempting an operation (e.g., open(2)) on the file. Similarly, for the root user, the check uses the set of permitted capabilities rather than the set of effective capabilities; ***and for non-root users, the check uses an empty set of capabilities.*** " What that means is that for non-root user the access API will not do the proper validation if the process really has permission to a file or not. To resolve this this patch replaces all the access API calls with faccessat with AT_EACCESS flag. Signed-off-by: Jon Doron <jond@wiz.io> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20220925070431.1313680-1-arilou@gmail.com
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01f2e36c |
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12-Sep-2022 |
Tao Chen <chentao.kernel@linux.alibaba.com> |
libbpf: Support raw BTF placed in the default search path Currently, the default vmlinux files at '/boot/vmlinux-*', '/lib/modules/*/vmlinux-*' etc. are parsed with 'btf__parse_elf()' to extract BTF. It is possible that these files are actually raw BTF files similar to /sys/kernel/btf/vmlinux. So parse these files with 'btf__parse' which tries both raw format and ELF format. This might be useful in some scenarios where users put their custom BTF into known locations and don't want to specify btf_custom_path option. Signed-off-by: Tao Chen <chentao.kernel@linux.alibaba.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Acked-by: Yonghong Song <yhs@fb.com> Link: https://lore.kernel.org/bpf/3f59fb5a345d2e4f10e16fe9e35fbc4c03ecaa3e.1662999860.git.chentao.kernel@linux.alibaba.com
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abf84b64 |
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15-Aug-2022 |
Andrii Nakryiko <andrii@kernel.org> |
libbpf: Clean up deprecated and legacy aliases Remove three missed deprecated APIs that were aliased to new APIs: bpf_object__unload, bpf_prog_attach_xattr and btf__load. Also move legacy API libbpf_find_kernel_btf (aliased to btf__load_vmlinux_btf) into libbpf_legacy.h. Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Hao Luo <haoluo@google.com> Link: https://lore.kernel.org/bpf/20220816001929.369487-4-andrii@kernel.org
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aaf6886d |
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27-Jun-2022 |
Andrii Nakryiko <andrii@kernel.org> |
libbpf: remove deprecated BTF APIs 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>
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2ef20263 |
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07-Jun-2022 |
Yonghong Song <yhs@fb.com> |
libbpf: Add enum64 deduplication support 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>
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dffbbdc2 |
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07-Jun-2022 |
Yonghong Song <yhs@fb.com> |
libbpf: Add enum64 parsing and new enum64 public API 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>
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8479aa75 |
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07-Jun-2022 |
Yonghong Song <yhs@fb.com> |
libbpf: Refactor btf__add_enum() for future code sharing 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>
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9bbdfad8 |
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01-Jun-2022 |
Daniel Müller <deso@posteo.net> |
libbpf: Fix a couple of typos 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
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610cd93b |
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24-May-2022 |
Douglas Raillard <douglas.raillard@arm.com> |
libbpf: Fix determine_ptr_size() guessing 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
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11d5daa8 |
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25-Apr-2022 |
Andrii Nakryiko <andrii@kernel.org> |
libbpf: Avoid joining .BTF.ext data with BPF programs by section name Instead of using ELF section names as a joining key between .BTF.ext and corresponding BPF programs, pre-build .BTF.ext section number to ELF section index mapping during bpf_object__open() and use it later for matching .BTF.ext information (func/line info or CO-RE relocations) to their respective BPF programs and subprograms. This simplifies corresponding joining logic and let's libbpf do manipulations with BPF program's ELF sections like dropping leading '?' character for non-autoloaded programs. Original joining logic in bpf_object__relocate_core() (see relevant comment that's now removed) was never elegant, so it's a good improvement regardless. But it also avoids unnecessary internal assumptions about preserving original ELF section name as BPF program's section name (which was broken when SEC("?abc") support was added). Fixes: a3820c481112 ("libbpf: Support opting out from autoloading BPF programs declaratively") Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20220426004511.2691730-5-andrii@kernel.org
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e93f3999 |
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03-Apr-2022 |
Yuntao Wang <ytcoode@gmail.com> |
libbpf: Don't return -EINVAL if hdr_len < offsetofend(core_relo_len) Since core relos is an optional part of the .BTF.ext ELF section, we should skip parsing it instead of returning -EINVAL if header size is less than offsetofend(struct btf_ext_header, core_relo_len). Signed-off-by: Yuntao Wang <ytcoode@gmail.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20220404005320.1723055-1-ytcoode@gmail.com
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d81283d2 |
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19-Jan-2022 |
Kui-Feng Lee <kuifeng@fb.com> |
libbpf: Improve btf__add_btf() with an additional hashmap for strings. Add a hashmap to map the string offsets from a source btf to the string offsets from a target btf to reduce overheads. btf__add_btf() calls btf__add_str() to add strings from a source to a target btf. It causes many string comparisons, and it is a major hotspot when adding a big btf. btf__add_str() uses strcmp() to check if a hash entry is the right one. The extra hashmap here compares offsets of strings, that are much cheaper. It remembers the results of btf__add_str() for later uses to reduce the cost. We are parallelizing BTF encoding for pahole by creating separated btf instances for worker threads. These per-thread btf instances will be added to the btf instance of the main thread by calling btf__add_str() to deduplicate and write out. With this patch and -j4, the running time of pahole drops to about 6.0s from 6.6s. The following lines are the summary of 'perf stat' w/o the change. 6.668126396 seconds time elapsed 13.451054000 seconds user 0.715520000 seconds sys The following lines are the summary w/ the change. 5.986973919 seconds time elapsed 12.939903000 seconds user 0.724152000 seconds sys V4 fixes a bug of error checking against the pointer returned by hashmap__new(). [v3] https://lore.kernel.org/bpf/20220118232053.2113139-1-kuifeng@fb.com/ [v2] https://lore.kernel.org/bpf/20220114193713.461349-1-kuifeng@fb.com/ Signed-off-by: Kui-Feng Lee <kuifeng@fb.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20220119180214.255634-1-kuifeng@fb.com
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b69c5c07 |
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09-Dec-2021 |
Vincent Minet <vincent@vincent-minet.net> |
libbpf: Fix typo in btf__dedup@LIBBPF_0.0.2 definition The btf__dedup_deprecated name was misspelled in the definition of the compat symbol for btf__dedup. This leads it to be missing from the shared library. This fixes it. Fixes: 957d350a8b94 ("libbpf: Turn btf_dedup_opts into OPTS-based struct") Signed-off-by: Vincent Minet <vincent@vincent-minet.net> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20211210063112.80047-1-vincent@vincent-minet.net
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1a190d1e |
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09-Dec-2021 |
Andrii Nakryiko <andrii@kernel.org> |
libbpf: Allow passing preallocated log_buf when loading BTF into kernel Add libbpf-internal btf_load_into_kernel() that allows to pass preallocated log_buf and custom log_level to be passed into kernel during BPF_BTF_LOAD call. When custom log_buf is provided, btf_load_into_kernel() won't attempt an retry with automatically allocated internal temporary buffer to capture BTF validation log. It's important to note the relation between log_buf and log_level, which slightly deviates from stricter kernel logic. From kernel's POV, if log_buf is specified, log_level has to be > 0, and vice versa. While kernel has good reasons to request such "sanity, this, in practice, is a bit unconvenient and restrictive for libbpf's high-level bpf_object APIs. So libbpf will allow to set non-NULL log_buf and log_level == 0. This is fine and means to attempt to load BTF without logging requested, but if it failes, retry the load with custom log_buf and log_level 1. Similar logic will be implemented for program loading. In practice this means that users can provide custom log buffer just in case error happens, but not really request slower verbose logging all the time. This is also consistent with libbpf behavior when custom log_buf is not set: libbpf first tries to load everything with log_level=0, and only if error happens allocates internal log buffer and retries with log_level=1. Also, while at it, make BTF validation log more obvious and follow the log pattern libbpf is using for dumping BPF verifier log during BPF_PROG_LOAD. BTF loading resulting in an error will look like this: libbpf: BTF loading error: -22 libbpf: -- BEGIN BTF LOAD LOG --- magic: 0xeb9f version: 1 flags: 0x0 hdr_len: 24 type_off: 0 type_len: 1040 str_off: 1040 str_len: 2063598257 btf_total_size: 1753 Total section length too long -- END BTF LOAD LOG -- libbpf: Error loading .BTF into kernel: -22. BTF is optional, ignoring. This makes it much easier to find relevant parts in libbpf log output. Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20211209193840.1248570-4-andrii@kernel.org
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74753e14 |
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01-Dec-2021 |
Alexei Starovoitov <ast@kernel.org> |
libbpf: Replace btf__type_by_id() with btf_type_by_id(). To prepare relo_core.c to be compiled in the kernel and the user space replace btf__type_by_id with btf_type_by_id. In libbpf btf__type_by_id and btf_type_by_id have different behavior. bpf_core_apply_relo_insn() needs behavior of uapi btf__type_by_id vs internal btf_type_by_id, but type_id range check is already done in bpf_core_apply_relo(), so it's safe to replace it everywhere. The kernel btf_type_by_id() does the check anyway. It doesn't hurt. Suggested-by: Andrii Nakryiko <andrii@kernel.org> 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/20211201181040.23337-2-alexei.starovoitov@gmail.com
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401891a9 |
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23-Nov-2021 |
Andrii Nakryiko <andrii@kernel.org> |
libbpf: Fix potential misaligned memory access in btf_ext__new() Perform a memory copy before we do the sanity checks of btf_ext_hdr. This prevents misaligned memory access if raw btf_ext data is not 4-byte aligned ([0]). While at it, also add missing const qualifier. [0] Closes: https://github.com/libbpf/libbpf/issues/391 Fixes: 2993e0515bb4 ("tools/bpf: add support to read .BTF.ext sections") Reported-by: Evgeny Vereshchagin <evvers@ya.ru> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Link: https://lore.kernel.org/bpf/20211124002325.1737739-3-andrii@kernel.org
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efdd3eb8 |
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17-Nov-2021 |
Andrii Nakryiko <andrii@kernel.org> |
libbpf: Accommodate DWARF/compiler bug with duplicated structs According to [0], compilers sometimes might produce duplicate DWARF definitions for exactly the same struct/union within the same compilation unit (CU). We've had similar issues with identical arrays and handled them with a similar workaround in 6b6e6b1d09aa ("libbpf: Accomodate DWARF/compiler bug with duplicated identical arrays"). Do the same for struct/union by ensuring that two structs/unions are exactly the same, down to the integer values of field referenced type IDs. Solving this more generically (allowing referenced types to be equivalent, but using different type IDs, all within a single CU) requires a huge complexity increase to handle many-to-many mappings between canonidal and candidate type graphs. Before we invest in that, let's see if this approach handles all the instances of this issue in practice. Thankfully it's pretty rare, it seems. [0] https://lore.kernel.org/bpf/YXr2NFlJTAhHdZqq@krava/ Reported-by: Jiri Olsa <jolsa@kernel.org> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Link: https://lore.kernel.org/bpf/20211117194114.347675-1-andrii@kernel.org
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69a055d5 |
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15-Nov-2021 |
Yonghong Song <yhs@fb.com> |
libbpf: Fix a couple of missed btf_type_tag handling in btf.c Commit 2dc1e488e5cd ("libbpf: Support BTF_KIND_TYPE_TAG") added the BTF_KIND_TYPE_TAG support. But to test vmlinux build with ... #define __user __attribute__((btf_type_tag("user"))) ... I needed to sync libbpf repo and manually copy libbpf sources to pahole. To simplify process, I used BTF_KIND_RESTRICT to simulate the BTF_KIND_TYPE_TAG with vmlinux build as "restrict" modifier is barely used in kernel. But this approach missed one case in dedup with structures where BTF_KIND_RESTRICT is handled and BTF_KIND_TYPE_TAG is not handled in btf_dedup_is_equiv(), and this will result in a pahole dedup failure. This patch fixed this issue and a selftest is added in the subsequent patch to test this scenario. The other missed handling is in btf__resolve_size(). Currently the compiler always emit like PTR->TYPE_TAG->... so in practice we don't hit the missing BTF_KIND_TYPE_TAG handling issue with compiler generated code. But lets add case BTF_KIND_TYPE_TAG in the switch statement to be future proof. Fixes: 2dc1e488e5cd ("libbpf: Support BTF_KIND_TYPE_TAG") Signed-off-by: Yonghong Song <yhs@fb.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Link: https://lore.kernel.org/bpf/20211115163937.3922235-1-yhs@fb.com
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2dc1e488 |
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11-Nov-2021 |
Yonghong Song <yhs@fb.com> |
libbpf: Support BTF_KIND_TYPE_TAG Add libbpf support for BTF_KIND_TYPE_TAG. Signed-off-by: Yonghong Song <yhs@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20211112012614.1505315-1-yhs@fb.com
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957d350a |
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10-Nov-2021 |
Andrii Nakryiko <andrii@kernel.org> |
libbpf: Turn btf_dedup_opts into OPTS-based struct btf__dedup() and struct btf_dedup_opts were added before we figured out OPTS mechanism. As such, btf_dedup_opts is non-extensible without breaking an ABI and potentially crashing user application. Unfortunately, btf__dedup() and btf_dedup_opts are short and succinct names that would be great to preserve and use going forward. So we use ___libbpf_override() macro approach, used previously for bpf_prog_load() API, to define a new btf__dedup() variant that accepts only struct btf * and struct btf_dedup_opts * arguments, and rename the old btf__dedup() implementation into btf__dedup_deprecated(). This keeps both source and binary compatibility with old and new applications. The biggest problem was struct btf_dedup_opts, which wasn't OPTS-based, and as such doesn't have `size_t sz;` as a first field. But btf__dedup() is a pretty rarely used API and I believe that the only currently known users (besides selftests) are libbpf's own bpf_linker and pahole. Neither use case actually uses options and just passes NULL. So instead of doing extra hacks, just rewrite struct btf_dedup_opts into OPTS-based one, move btf_ext argument into those opts (only bpf_linker needs to dedup btf_ext, so it's not a typical thing to specify), and drop never used `dont_resolve_fwds` option (it was never used anywhere, AFAIK, it makes BTF dedup much less useful and efficient). Just in case, for old implementation, btf__dedup_deprecated(), detect non-NULL options and error out with helpful message, to help users migrate, if there are any user playing with btf__dedup(). The last remaining piece is dedup_table_size, which is another anachronism from very early days of BTF dedup. Since then it has been reduced to the only valid value, 1, to request forced hash collisions. This is only used during testing. So instead introduce a bool flag to force collisions explicitly. This patch also adapts selftests to new btf__dedup() and btf_dedup_opts use to avoid selftests breakage. [0] Closes: https://github.com/libbpf/libbpf/issues/281 Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20211111053624.190580-4-andrii@kernel.org
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92274e24 |
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27-Oct-2021 |
Kumar Kartikeya Dwivedi <memxor@gmail.com> |
libbpf: Use O_CLOEXEC uniformly when opening fds There are some instances where we don't use O_CLOEXEC when opening an fd, fix these up. Otherwise, it is possible that a parallel fork causes these fds to leak into a child process on execve. Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20211028063501.2239335-6-memxor@gmail.com
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3930198d |
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25-Oct-2021 |
Ilya Leoshkevich <iii@linux.ibm.com> |
libbpf: Use __BYTE_ORDER__ Use the compiler-defined __BYTE_ORDER__ instead of the libc-defined __BYTE_ORDER for consistency. Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20211026010831.748682-3-iii@linux.ibm.com
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c825f5fe |
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22-Oct-2021 |
Andrii Nakryiko <andrii@kernel.org> |
libbpf: Fix BTF header parsing checks Original code assumed fixed and correct BTF header length. That's not always the case, though, so fix this bug with a proper additional check. And use actual header length instead of sizeof(struct btf_header) in sanity checks. Fixes: 8a138aed4a80 ("bpf: btf: Add BTF support to libbpf") Reported-by: Evgeny Vereshchagin <evvers@ya.ru> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20211023003157.726961-2-andrii@kernel.org
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5245dafe |
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22-Oct-2021 |
Andrii Nakryiko <andrii@kernel.org> |
libbpf: Fix overflow in BTF sanity checks btf_header's str_off+str_len or type_off+type_len can overflow as they are u32s. This will lead to bypassing the sanity checks during BTF parsing, resulting in crashes afterwards. Fix by using 64-bit signed integers for comparison. Fixes: d8123624506c ("libbpf: Fix BTF data layout checks and allow empty BTF") Reported-by: Evgeny Vereshchagin <evvers@ya.ru> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20211023003157.726961-1-andrii@kernel.org
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6a886de0 |
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22-Oct-2021 |
Hengqi Chen <hengqi.chen@gmail.com> |
libbpf: Add btf__type_cnt() and btf__raw_data() APIs Add btf__type_cnt() and btf__raw_data() APIs and deprecate btf__get_nr_type() and btf__get_raw_data() since the old APIs don't follow the libbpf naming convention for getters which omit 'get' in the name (see [0]). btf__raw_data() is just an alias to the existing btf__get_raw_data(). btf__type_cnt() now returns the number of all types of the BTF object including 'void'. [0] Closes: https://github.com/libbpf/libbpf/issues/279 Signed-off-by: Hengqi Chen <hengqi.chen@gmail.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20211022130623.1548429-2-hengqi.chen@gmail.com
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1000298c |
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22-Oct-2021 |
Mauricio Vásquez <mauricio@kinvolk.io> |
libbpf: Fix memory leak in btf__dedup() Free btf_dedup if btf_ensure_modifiable() returns error. Fixes: 919d2b1dbb07 ("libbpf: Allow modification of BTF and add btf__add_str API") Signed-off-by: Mauricio Vásquez <mauricio@kinvolk.io> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20211022202035.48868-1-mauricio@kinvolk.io
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b96c07f3 |
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20-Oct-2021 |
Andrii Nakryiko <andrii@kernel.org> |
libbpf: Deprecate btf__finalize_data() and move it into libbpf.c There isn't a good use case where anyone but libbpf itself needs to call btf__finalize_data(). It was implemented for internal use and it's not clear why it was made into public API in the first place. To function, it requires active ELF data, which is stored inside bpf_object for the duration of opening phase only. But the only BTF that needs bpf_object's ELF is that bpf_object's BTF itself, which libbpf fixes up automatically during bpf_object__open() operation anyways. There is no need for any additional fix up and no reasonable scenario where it's useful and appropriate. Thus, btf__finalize_data() is just an API atavism and is better removed. So this patch marks it as deprecated immediately (v0.6+) and moves the code from btf.c into libbpf.c where it's used in the context of bpf_object opening phase. Such code co-location allows to make code structure more straightforward and remove bpf_object__section_size() and bpf_object__variable_offset() internal helpers from libbpf_internal.h, making them static. Their naming is also adjusted to not create a wrong illusion that they are some sort of method of bpf_object. They are internal helpers and are called appropriately. This is part of libbpf 1.0 effort ([0]). [0] Closes: https://github.com/libbpf/libbpf/issues/276 Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Song Liu <songliubraving@fb.com> Link: https://lore.kernel.org/bpf/20211021014404.2635234-2-andrii@kernel.org
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223f903e |
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12-Oct-2021 |
Yonghong Song <yhs@fb.com> |
bpf: Rename BTF_KIND_TAG to BTF_KIND_DECL_TAG Patch set [1] introduced BTF_KIND_TAG to allow tagging declarations for struct/union, struct/union field, var, func and func arguments and these tags will be encoded into dwarf. They are also encoded to btf by llvm for the bpf target. After BTF_KIND_TAG is introduced, we intended to use it for kernel __user attributes. But kernel __user is actually a type attribute. Upstream and internal discussion showed it is not a good idea to mix declaration attribute and type attribute. So we proposed to introduce btf_type_tag as a type attribute and existing btf_tag renamed to btf_decl_tag ([2]). This patch renamed BTF_KIND_TAG to BTF_KIND_DECL_TAG and some other declarations with *_tag to *_decl_tag to make it clear the tag is for declaration. In the future, BTF_KIND_TYPE_TAG might be introduced per [3]. [1] https://lore.kernel.org/bpf/20210914223004.244411-1-yhs@fb.com/ [2] https://reviews.llvm.org/D111588 [3] https://reviews.llvm.org/D111199 Fixes: b5ea834dde6b ("bpf: Support for new btf kind BTF_KIND_TAG") Fixes: 5b84bd10363e ("libbpf: Add support for BTF_KIND_TAG") Fixes: 5c07f2fec003 ("bpftool: Add support for BTF_KIND_TAG") Signed-off-by: Yonghong Song <yhs@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20211012164838.3345699-1-yhs@fb.com
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7ca61121 |
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05-Oct-2021 |
Andrii Nakryiko <andrii@kernel.org> |
libbpf: Add API that copies all BTF types from one BTF object to another Add a bulk copying api, btf__add_btf(), that speeds up and simplifies appending entire contents of one BTF object to another one, taking care of copying BTF type data, adjusting resulting BTF type IDs according to their new locations in the destination BTF object, as well as copying and deduplicating all the referenced strings and updating all the string offsets in new BTF types as appropriate. This API is intended to be used from tools that are generating and otherwise manipulating BTFs generically, such as pahole. In pahole's case, this API is useful for speeding up parallelized BTF encoding, as it allows pahole to offload all the intricacies of BTF type copying to libbpf and handle the parallelization aspects of the process. Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Song Liu <songliubraving@fb.com> Cc: Arnaldo Carvalho de Melo <acme@kernel.org> Link: https://lore.kernel.org/bpf/20211006051107.17921-2-andrii@kernel.org
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9dbe6015 |
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01-Oct-2021 |
Kumar Kartikeya Dwivedi <memxor@gmail.com> |
libbpf: Support kernel module function calls This patch adds libbpf support for kernel module function call support. The fd_array parameter is used during BPF program load to pass module BTFs referenced by the program. insn->off is set to index into this array, but starts from 1, because insn->off as 0 is reserved for btf_vmlinux. We try to use existing insn->off for a module, since the kernel limits the maximum distinct module BTFs for kfuncs to 256, and also because index must never exceed the maximum allowed value that can fit in insn->off (INT16_MAX). In the future, if kernel interprets signed offset as unsigned for kfunc calls, this limit can be increased to UINT16_MAX. Also introduce a btf__find_by_name_kind_own helper to start searching from module BTF's start id when we know that the BTF ID is not present in vmlinux BTF (in find_ksym_btf_id). Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20211002011757.311265-7-memxor@gmail.com
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5b84bd10 |
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14-Sep-2021 |
Yonghong Song <yhs@fb.com> |
libbpf: Add support for BTF_KIND_TAG Add BTF_KIND_TAG support for parsing and dedup. Also added sanitization for BTF_KIND_TAG. If BTF_KIND_TAG is not supported in the kernel, sanitize it to INTs. Signed-off-by: Yonghong Song <yhs@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20210914223025.246687-1-yhs@fb.com
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30025e8b |
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14-Sep-2021 |
Yonghong Song <yhs@fb.com> |
libbpf: Rename btf_{hash,equal}_int to btf_{hash,equal}_int_tag This patch renames functions btf_{hash,equal}_int() to btf_{hash,equal}_int_tag() so they can be reused for BTF_KIND_TAG support. There is no functionality change for this patch. Signed-off-by: Yonghong Song <yhs@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20210914223020.245829-1-yhs@fb.com
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a710eed3 |
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30-Jul-2021 |
Hengqi Chen <hengqi.chen@gmail.com> |
libbpf: Add btf__load_vmlinux_btf/btf__load_module_btf Add two new APIs: btf__load_vmlinux_btf and btf__load_module_btf. btf__load_vmlinux_btf is just an alias to the existing API named libbpf_find_kernel_btf, rename to be more precisely and consistent with existing BTF APIs. btf__load_module_btf can be used to load module BTF, add it for completeness. These two APIs are useful for implementing tracing tools and introspection tools. This is part of the effort towards libbpf 1.0 ([0]). [0] Closes: https://github.com/libbpf/libbpf/issues/280 Signed-off-by: Hengqi Chen <hengqi.chen@gmail.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20210730114012.494408-1-hengqi.chen@gmail.com
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61fc51b1 |
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29-Jul-2021 |
Quentin Monnet <quentin@isovalent.com> |
libbpf: Add split BTF support for btf__load_from_kernel_by_id() Add a new API function btf__load_from_kernel_by_id_split(), which takes a pointer to a base BTF object in order to support split BTF objects when retrieving BTF information from the kernel. Reference: https://github.com/libbpf/libbpf/issues/314 Signed-off-by: Quentin Monnet <quentin@isovalent.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Acked-by: John Fastabend <john.fastabend@gmail.com> Link: https://lore.kernel.org/bpf/20210729162028.29512-8-quentin@isovalent.com
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6cc93e2f |
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29-Jul-2021 |
Quentin Monnet <quentin@isovalent.com> |
libbpf: Rename btf__get_from_id() as btf__load_from_kernel_by_id() Rename function btf__get_from_id() as btf__load_from_kernel_by_id() to better indicate what the function does. Change the new function so that, instead of requiring a pointer to the pointer to update and returning with an error code, it takes a single argument (the id of the BTF object) and returns the corresponding pointer. This is more in line with the existing constructors. The other tools calling the (soon-to-be) deprecated btf__get_from_id() function will be updated in a future commit. References: - https://github.com/libbpf/libbpf/issues/278 - https://github.com/libbpf/libbpf/wiki/Libbpf:-the-road-to-v1.0#btfh-apis Signed-off-by: Quentin Monnet <quentin@isovalent.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Acked-by: John Fastabend <john.fastabend@gmail.com> Link: https://lore.kernel.org/bpf/20210729162028.29512-4-quentin@isovalent.com
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3c7e5859 |
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29-Jul-2021 |
Quentin Monnet <quentin@isovalent.com> |
libbpf: Rename btf__load() as btf__load_into_kernel() As part of the effort to move towards a v1.0 for libbpf, rename btf__load() function, used to "upload" BTF information into the kernel, as btf__load_into_kernel(). This new name better reflects what the function does. References: - https://github.com/libbpf/libbpf/issues/278 - https://github.com/libbpf/libbpf/wiki/Libbpf:-the-road-to-v1.0#btfh-apis Signed-off-by: Quentin Monnet <quentin@isovalent.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Acked-by: John Fastabend <john.fastabend@gmail.com> Link: https://lore.kernel.org/bpf/20210729162028.29512-3-quentin@isovalent.com
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c34c338a |
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28-Jul-2021 |
Daniel Xu <dxu@dxuuu.xyz> |
libbpf: Do not close un-owned FD 0 on errors Before this patch, btf_new() was liable to close an arbitrary FD 0 if BTF parsing failed. This was because: * btf->fd was initialized to 0 through the calloc() * btf__free() (in the `done` label) closed any FDs >= 0 * btf->fd is left at 0 if parsing fails This issue was discovered on a system using libbpf v0.3 (without BTF_KIND_FLOAT support) but with a kernel that had BTF_KIND_FLOAT types in BTF. Thus, parsing fails. While this patch technically doesn't fix any issues b/c upstream libbpf has BTF_KIND_FLOAT support, it'll help prevent issues in the future if more BTF types are added. It also allow the fix to be backported to older libbpf's. Fixes: 3289959b97ca ("libbpf: Support BTF loading and raw data output in both endianness") Signed-off-by: Daniel Xu <dxu@dxuuu.xyz> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Yonghong Song <yhs@fb.com> Link: https://lore.kernel.org/bpf/5969bb991adedb03c6ae93e051fd2a00d293cf25.1627513670.git.dxu@dxuuu.xyz
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e9fc3ce9 |
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24-May-2021 |
Andrii Nakryiko <andrii@kernel.org> |
libbpf: Streamline error reporting for high-level APIs Implement changes to error reporting for high-level libbpf APIs to make them less surprising and less error-prone to users: - in all the cases when error happens, errno is set to an appropriate error value; - in libbpf 1.0 mode, all pointer-returning APIs return NULL on error and error code is communicated through errno; this applies both to APIs that already returned NULL before (so now they communicate more detailed error codes), as well as for many APIs that used ERR_PTR() macro and encoded error numbers as fake pointers. - in legacy (default) mode, those APIs that were returning ERR_PTR(err), continue doing so, but still set errno. With these changes, errno can be always used to extract actual error, regardless of legacy or libbpf 1.0 modes. This is utilized internally in libbpf in places where libbpf uses it's own high-level APIs. libbpf_get_error() is adapted to handle both cases completely transparently to end-users (and is used by libbpf consistently as well). More context, justification, and discussion can be found in "Libbpf: the road to v1.0" document ([0]). [0] https://docs.google.com/document/d/1UyjTZuPFWiPFyKk1tV5an11_iaRuec6U-ZESZ54nNTY Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: John Fastabend <john.fastabend@gmail.com> Acked-by: Toke Høiland-Jørgensen <toke@redhat.com> Link: https://lore.kernel.org/bpf/20210525035935.1461796-5-andrii@kernel.org
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aea28a60 |
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23-Apr-2021 |
Andrii Nakryiko <andrii@kernel.org> |
libbpf: Mark BPF subprogs with hidden visibility as static for BPF verifier Define __hidden helper macro in bpf_helpers.h, which is a short-hand for __attribute__((visibility("hidden"))). Add libbpf support to mark BPF subprograms marked with __hidden as static in BTF information to enforce BPF verifier's static function validation algorithm, which takes more information (caller's context) into account during a subprogram validation. Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Yonghong Song <yhs@fb.com> Link: https://lore.kernel.org/bpf/20210423181348.1801389-5-andrii@kernel.org
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9af44bc5 |
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18-Mar-2021 |
Andrii Nakryiko <andrii@kernel.org> |
libbpf: Add generic BTF type shallow copy API Add btf__add_type() API that performs shallow copy of a given BTF type from the source BTF into the destination BTF. All the information and type IDs are preserved, but all the strings encountered are added into the destination BTF and corresponding offsets are rewritten. BTF type IDs are assumed to be correct or such that will be (somehow) modified afterwards. Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20210318194036.3521577-6-andrii@kernel.org
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90d76d3e |
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18-Mar-2021 |
Andrii Nakryiko <andrii@kernel.org> |
libbpf: Extract internal set-of-strings datastructure APIs Extract BTF logic for maintaining a set of strings data structure, used for BTF strings section construction in writable mode, into separate re-usable API. This data structure is going to be used by bpf_linker to maintains ELF STRTAB section, which has the same layout as BTF strings section. Suggested-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20210318194036.3521577-5-andrii@kernel.org
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3b029e06 |
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18-Mar-2021 |
Andrii Nakryiko <andrii@kernel.org> |
libbpf: Rename internal memory-management helpers Rename btf_add_mem() and btf_ensure_mem() helpers that abstract away details of dynamically resizable memory to use libbpf_ prefix, as they are not BTF-specific. No functional changes. Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20210318194036.3521577-4-andrii@kernel.org
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f36e99a4 |
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18-Mar-2021 |
Andrii Nakryiko <andrii@kernel.org> |
libbpf: Generalize BTF and BTF.ext type ID and strings iteration Extract and generalize the logic to iterate BTF type ID and string offset fields within BTF types and .BTF.ext data. Expose this internally in libbpf for re-use by bpf_linker. Additionally, complete strings deduplication handling for BTF.ext (e.g., CO-RE access strings), which was previously missing. There previously was no case of deduplicating .BTF.ext data, but bpf_linker is going to use it. Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20210318194036.3521577-3-andrii@kernel.org
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e14ef4bf |
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18-Mar-2021 |
Andrii Nakryiko <andrii@kernel.org> |
libbpf: Expose btf_type_by_id() internally btf_type_by_id() is internal-only convenience API returning non-const pointer to struct btf_type. Expose it outside of btf.c for re-use. Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20210318194036.3521577-2-andrii@kernel.org
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22541a9e |
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26-Feb-2021 |
Ilya Leoshkevich <iii@linux.ibm.com> |
libbpf: Add BTF_KIND_FLOAT support The logic follows that of BTF_KIND_INT most of the time. Sanitization replaces BTF_KIND_FLOATs with equally-sized empty BTF_KIND_STRUCTs on older kernels, for example, the following: [4] FLOAT 'float' size=4 becomes the following: [4] STRUCT '(anon)' size=4 vlen=0 With dwarves patch [1] and this patch, the older kernels, which were failing with the floating-point-related errors, will now start working correctly. [1] https://github.com/iii-i/dwarves/commit/btf-kind-float-v2 Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20210226202256.116518-4-iii@linux.ibm.com
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1b1ce92b |
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26-Feb-2021 |
Ilya Leoshkevich <iii@linux.ibm.com> |
libbpf: Fix whitespace in btf_add_composite() comment Remove trailing space. Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Yonghong Song <yhs@fb.com> Link: https://lore.kernel.org/bpf/20210226202256.116518-3-iii@linux.ibm.com
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6095d5a2 |
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21-Jan-2021 |
Jiri Olsa <jolsa@kernel.org> |
libbpf: Use string table index from index table if needed For very large ELF objects (with many sections), we could get special value SHN_XINDEX (65535) for elf object's string table index - e_shstrndx. Call elf_getshdrstrndx to get the proper string table index, instead of reading it directly from ELF header. Signed-off-by: Jiri Olsa <jolsa@kernel.org> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20210121202203.9346-4-jolsa@kernel.org
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b8d52264 |
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10-Jan-2021 |
Andrii Nakryiko <andrii@kernel.org> |
libbpf: Allow loading empty BTFs Empty BTFs do come up (e.g., simple kernel modules with no new types and strings, compared to the vmlinux BTF) and there is nothing technically wrong with them. So remove unnecessary check preventing loading empty BTFs. Fixes: d8123624506c ("libbpf: Fix BTF data layout checks and allow empty BTF") Reported-by: Christopher William Snowhill <chris@kode54.net> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Link: https://lore.kernel.org/bpf/20210110070341.1380086-2-andrii@kernel.org
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a19f93cf |
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03-Dec-2020 |
Andrii Nakryiko <andrii@kernel.org> |
libbpf: Add internal helper to load BTF data by FD Add a btf_get_from_fd() helper, which constructs struct btf from in-kernel BTF data by FD. This is used for loading module BTFs. Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20201203204634.1325171-4-andrii@kernel.org
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0cfdcd63 |
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01-Dec-2020 |
Andrii Nakryiko <andrii@kernel.org> |
libbpf: Add base BTF accessor Add ability to get base BTF. It can be also used to check if BTF is split BTF. Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20201202065244.530571-3-andrii@kernel.org
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de91e631 |
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15-Nov-2020 |
Alan Maguire <alan.maguire@oracle.com> |
libbpf: bpf__find_by_name[_kind] should use btf__get_nr_types() When operating on split BTF, btf__find_by_name[_kind] will not iterate over all types since they use btf->nr_types to show the number of types to iterate over. For split BTF this is the number of types _on top of base BTF_, so it will underestimate the number of types to iterate over, especially for vmlinux + module BTF, where the latter is much smaller. Use btf__get_nr_types() instead. Fixes: ba451366bf44 ("libbpf: Implement basic split BTF support") Signed-off-by: Alan Maguire <alan.maguire@oracle.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/1605437195-2175-1-git-send-email-alan.maguire@oracle.com
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6b6e6b1d |
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04-Nov-2020 |
Andrii Nakryiko <andrii@kernel.org> |
libbpf: Accomodate DWARF/compiler bug with duplicated identical arrays In some cases compiler seems to generate distinct DWARF types for identical arrays within the same CU. That seems like a bug, but it's already out there and breaks type graph equivalence checks, so accommodate it anyway by checking for identical arrays, regardless of their type ID. Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Song Liu <songliubraving@fb.com> Link: https://lore.kernel.org/bpf/20201105043402.2530976-10-andrii@kernel.org
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f86524ef |
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04-Nov-2020 |
Andrii Nakryiko <andrii@kernel.org> |
libbpf: Support BTF dedup of split BTFs Add support for deduplication split BTFs. When deduplicating split BTF, base BTF is considered to be immutable and can't be modified or adjusted. 99% of BTF deduplication logic is left intact (module some type numbering adjustments). There are only two differences. First, each type in base BTF gets hashed (expect VAR and DATASEC, of course, those are always considered to be self-canonical instances) and added into a table of canonical table candidates. Hashing is a shallow, fast operation, so mostly eliminates the overhead of having entire base BTF to be a part of BTF dedup. Second difference is very critical and subtle. While deduplicating split BTF types, it is possible to discover that one of immutable base BTF BTF_KIND_FWD types can and should be resolved to a full STRUCT/UNION type from the split BTF part. This is, obviously, can't happen because we can't modify the base BTF types anymore. So because of that, any type in split BTF that directly or indirectly references that newly-to-be-resolved FWD type can't be considered to be equivalent to the corresponding canonical types in base BTF, because that would result in a loss of type resolution information. So in such case, split BTF types will be deduplicated separately and will cause some duplication of type information, which is unavoidable. With those two changes, the rest of the algorithm manages to deduplicate split BTF correctly, pointing all the duplicates to their canonical counter-parts in base BTF, but also is deduplicating whatever unique types are present in split BTF on their own. Also, theoretically, split BTF after deduplication could end up with either empty type section or empty string section. This is handled by libbpf correctly in one of previous patches in the series. Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Song Liu <songliubraving@fb.com> Link: https://lore.kernel.org/bpf/20201105043402.2530976-9-andrii@kernel.org
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d8123624 |
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04-Nov-2020 |
Andrii Nakryiko <andrii@kernel.org> |
libbpf: Fix BTF data layout checks and allow empty BTF Make data section layout checks stricter, disallowing overlap of types and strings data. Additionally, allow BTFs with no type data. There is nothing inherently wrong with having BTF with no types (put potentially with some strings). This could be a situation with kernel module BTFs, if module doesn't introduce any new type information. Also fix invalid offset alignment check for btf->hdr->type_off. Fixes: 8a138aed4a80 ("bpf: btf: Add BTF support to libbpf") Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20201105043402.2530976-8-andrii@kernel.org
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ba451366 |
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04-Nov-2020 |
Andrii Nakryiko <andrii@kernel.org> |
libbpf: Implement basic split BTF support Support split BTF operation, in which one BTF (base BTF) provides basic set of types and strings, while another one (split BTF) builds on top of base's types and strings and adds its own new types and strings. From API standpoint, the fact that the split BTF is built on top of the base BTF is transparent. Type numeration is transparent. If the base BTF had last type ID #N, then all types in the split BTF start at type ID N+1. Any type in split BTF can reference base BTF types, but not vice versa. Programmatically construction of a split BTF on top of a base BTF is supported: one can create an empty split BTF with btf__new_empty_split() and pass base BTF as an input, or pass raw binary data to btf__new_split(), or use btf__parse_xxx_split() variants to get initial set of split types/strings from the ELF file with .BTF section. String offsets are similarly transparent and are a logical continuation of base BTF's strings. When building BTF programmatically and adding a new string (explicitly with btf__add_str() or implicitly through appending new types/members), string-to-be-added would first be looked up from the base BTF's string section and re-used if it's there. If not, it will be looked up and/or added to the split BTF string section. Similarly to type IDs, types in split BTF can refer to strings from base BTF absolutely transparently (but not vice versa, of course, because base BTF doesn't "know" about existence of split BTF). Internal type index is slightly adjusted to be zero-indexed, ignoring a fake [0] VOID type. This allows to handle split/base BTF type lookups transparently by using btf->start_id type ID offset, which is always 1 for base/non-split BTF and equals btf__get_nr_types(base_btf) + 1 for the split BTF. BTF deduplication is not yet supported for split BTF and support for it will be added in separate patch. Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Song Liu <songliubraving@fb.com> Link: https://lore.kernel.org/bpf/20201105043402.2530976-5-andrii@kernel.org
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88a82c2a |
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04-Nov-2020 |
Andrii Nakryiko <andriin@fb.com> |
libbpf: Unify and speed up BTF string deduplication Revamp BTF dedup's string deduplication to match the approach of writable BTF string management. This allows to transfer deduplicated strings index back to BTF object after deduplication without expensive extra memory copying and hash map re-construction. It also simplifies the code and speeds it up, because hashmap-based string deduplication is faster than sort + unique approach. Signed-off-by: Andrii Nakryiko <andriin@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Song Liu <songliubraving@fb.com> Link: https://lore.kernel.org/bpf/20201105043402.2530976-4-andrii@kernel.org
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c81ed6d8 |
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04-Nov-2020 |
Andrii Nakryiko <andrii@kernel.org> |
libbpf: Factor out common operations in BTF writing APIs Factor out commiting of appended type data. Also extract fetching the very last type in the BTF (to append members to). These two operations are common across many APIs and will be easier to refactor with split BTF, if they are extracted into a single place. Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Song Liu <songliubraving@fb.com> Link: https://lore.kernel.org/bpf/20201105043402.2530976-2-andrii@kernel.org
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9c6c5c48 |
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29-Sep-2020 |
Andrii Nakryiko <andriin@fb.com> |
libbpf: Make btf_dump work with modifiable BTF Ensure that btf_dump can accommodate new BTF types being appended to BTF instance after struct btf_dump was created. This came up during attemp to use btf_dump for raw type dumping in selftests, but given changes are not excessive, it's good to not have any gotchas in API usage, so I decided to support such use case in general. Signed-off-by: Andrii Nakryiko <andriin@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20200929232843.1249318-2-andriin@fb.com
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33433913 |
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29-Sep-2020 |
Andrii Nakryiko <andriin@fb.com> |
libbpf: Fix uninitialized variable in btf_parse_type_sec Fix obvious unitialized variable use that wasn't reported by compiler. libbpf Makefile changes to catch such errors are added separately. Fixes: 3289959b97ca ("libbpf: Support BTF loading and raw data output in both endianness") 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/20200929220604.833631-1-andriin@fb.com
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3289959b |
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28-Sep-2020 |
Andrii Nakryiko <andriin@fb.com> |
libbpf: Support BTF loading and raw data output in both endianness Teach BTF to recognized wrong endianness and transparently convert it internally to host endianness. Original endianness of BTF will be preserved and used during btf__get_raw_data() to convert resulting raw data to the same endianness and a source raw_data. This means that little-endian host can parse big-endian BTF with no issues, all the type data will be presented to the client application in native endianness, but when it's time for emitting BTF to persist it in a file (e.g., after BTF deduplication), original non-native endianness will be preserved and stored. It's possible to query original endianness of BTF data with new btf__endianness() API. It's also possible to override desired output endianness with btf__set_endianness(), so that if application needs to load, say, big-endian BTF and store it as little-endian BTF, it's possible to manually override this. If btf__set_endianness() was used to change endianness, btf__endianness() will reflect overridden endianness. Given there are no known use cases for supporting cross-endianness for .BTF.ext, loading .BTF.ext in non-native endianness is not supported. Signed-off-by: Andrii Nakryiko <andriin@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20200929043046.1324350-3-andriin@fb.com
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9141f75a |
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28-Sep-2020 |
Andrii Nakryiko <andriin@fb.com> |
selftests/bpf: Test BTF writing APIs Add selftests for BTF writer APIs. Signed-off-by: Andrii Nakryiko <andriin@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: John Fastabend <john.fastabend@gmail.com> Link: https://lore.kernel.org/bpf/20200929020533.711288-4-andriin@fb.com
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f86ed050 |
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28-Sep-2020 |
Andrii Nakryiko <andriin@fb.com> |
libbpf: Add btf__str_by_offset() as a more generic variant of name_by_offset BTF strings are used not just for names, they can be arbitrary strings used for CO-RE relocations, line/func infos, etc. Thus "name_by_offset" terminology is too specific and might be misleading. Instead, introduce btf__str_by_offset() API which uses generic string terminology. Signed-off-by: Andrii Nakryiko <andriin@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: John Fastabend <john.fastabend@gmail.com> Link: https://lore.kernel.org/bpf/20200929020533.711288-3-andriin@fb.com
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4a3b33f8 |
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28-Sep-2020 |
Andrii Nakryiko <andriin@fb.com> |
libbpf: Add BTF writing APIs Add APIs for appending new BTF types at the end of BTF object. Each BTF kind has either one API of the form btf__add_<kind>(). For types that have variable amount of additional items (struct/union, enum, func_proto, datasec), additional API is provided to emit each such item. E.g., for emitting a struct, one would use the following sequence of API calls: btf__add_struct(...); btf__add_field(...); ... btf__add_field(...); Each btf__add_field() will ensure that the last BTF type is of STRUCT or UNION kind and will automatically increment that type's vlen field. All the strings are provided as C strings (const char *), not a string offset. This significantly improves usability of BTF writer APIs. All such strings will be automatically appended to string section or existing string will be re-used, if such string was already added previously. Each API attempts to do all the reasonable validations, like enforcing non-empty names for entities with required names, proper value bounds, various bit offset restrictions, etc. Type ID validation is minimal because it's possible to emit a type that refers to type that will be emitted later, so libbpf has no way to enforce such cases. User must be careful to properly emit all the necessary types and specify type IDs that will be valid in the finally generated BTF. Each of btf__add_<kind>() APIs return new type ID on success or negative value on error. APIs like btf__add_field() that emit additional items return zero on success and negative value on error. Signed-off-by: Andrii Nakryiko <andriin@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: John Fastabend <john.fastabend@gmail.com> Link: https://lore.kernel.org/bpf/20200929020533.711288-2-andriin@fb.com
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a871b043 |
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25-Sep-2020 |
Andrii Nakryiko <andriin@fb.com> |
libbpf: Add btf__new_empty() to create an empty BTF object Add an ability to create an empty BTF object from scratch. This is going to be used by pahole for BTF encoding. And also by selftest for convenient creation of BTF objects. Signed-off-by: Andrii Nakryiko <andriin@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: John Fastabend <john.fastabend@gmail.com> Link: https://lore.kernel.org/bpf/20200926011357.2366158-7-andriin@fb.com
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919d2b1d |
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25-Sep-2020 |
Andrii Nakryiko <andriin@fb.com> |
libbpf: Allow modification of BTF and add btf__add_str API Allow internal BTF representation to switch from default read-only mode, in which raw BTF data is a single non-modifiable block of memory with BTF header, types, and strings layed out sequentially and contiguously in memory, into a writable representation with types and strings data split out into separate memory regions, that can be dynamically expanded. Such writable internal representation is transparent to users of libbpf APIs, but allows to append new types and strings at the end of BTF, which is a typical use case when generating BTF programmatically. All the basic guarantees of BTF types and strings layout is preserved, i.e., user can get `struct btf_type *` pointer and read it directly. Such btf_type pointers might be invalidated if BTF is modified, so some care is required in such mixed read/write scenarios. Switch from read-only to writable configuration happens automatically the first time when user attempts to modify BTF by either adding a new type or new string. It is still possible to get raw BTF data, which is a single piece of memory that can be persisted in ELF section or into a file as raw BTF. Such raw data memory is also still owned by BTF and will be freed either when BTF object is freed or if another modification to BTF happens, as any modification invalidates BTF raw representation. This patch adds the first two BTF manipulation APIs: btf__add_str(), which allows to add arbitrary strings to BTF string section, and btf__find_str() which allows to find existing string offset, but not add it if it's missing. All the added strings are automatically deduplicated. This is achieved by maintaining an additional string lookup index for all unique strings. Such index is built when BTF is switched to modifiable mode. If at that time BTF strings section contained duplicate strings, they are not de-duplicated. This is done specifically to not modify the existing content of BTF (types, their string offsets, etc), which can cause confusion and is especially important property if there is struct btf_ext associated with struct btf. By following this "imperfect deduplication" process, btf_ext is kept consitent and correct. If deduplication of strings is necessary, it can be forced by doing BTF deduplication, at which point all the strings will be eagerly deduplicated and all string offsets both in struct btf and struct btf_ext will be updated. Signed-off-by: Andrii Nakryiko <andriin@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: John Fastabend <john.fastabend@gmail.com> Link: https://lore.kernel.org/bpf/20200926011357.2366158-6-andriin@fb.com
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192f5a1f |
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25-Sep-2020 |
Andrii Nakryiko <andriin@fb.com> |
libbpf: Generalize common logic for managing dynamically-sized arrays Managing dynamically-sized array is a common, but not trivial functionality, which significant amount of logic and code to implement properly. So instead of re-implementing it all the time, extract it into a helper function ans reuse. Signed-off-by: Andrii Nakryiko <andriin@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: John Fastabend <john.fastabend@gmail.com> Link: https://lore.kernel.org/bpf/20200926011357.2366158-4-andriin@fb.com
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b8604247 |
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25-Sep-2020 |
Andrii Nakryiko <andriin@fb.com> |
libbpf: Remove assumption of single contiguous memory for BTF data Refactor internals of struct btf to remove assumptions that BTF header, type data, and string data are layed out contiguously in a memory in a single memory allocation. Now we have three separate pointers pointing to the start of each respective are: header, types, strings. In the next patches, these pointers will be re-assigned to point to independently allocated memory areas, if BTF needs to be modified. Signed-off-by: Andrii Nakryiko <andriin@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: John Fastabend <john.fastabend@gmail.com> Link: https://lore.kernel.org/bpf/20200926011357.2366158-3-andriin@fb.com
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740e69c3 |
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25-Sep-2020 |
Andrii Nakryiko <andriin@fb.com> |
libbpf: Refactor internals of BTF type index Refactor implementation of internal BTF type index to not use direct pointers. Instead it uses offset relative to the start of types data section. This allows for types data to be reallocatable, enabling implementation of modifiable BTF. As now getting type by ID has an extra indirection step, convert all internal type lookups to a new helper btf_type_id(), that returns non-const pointer to a type by its ID. Signed-off-by: Andrii Nakryiko <andriin@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: John Fastabend <john.fastabend@gmail.com> Link: https://lore.kernel.org/bpf/20200926011357.2366158-2-andriin@fb.com
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12450081 |
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19-Sep-2020 |
Tony Ambardar <tony.ambardar@gmail.com> |
libbpf: Fix native endian assumption when parsing BTF Code in btf__parse_raw() fails to detect raw BTF of non-native endianness and assumes it must be ELF data, which then fails to parse as ELF and yields a misleading error message: root:/# bpftool btf dump file /sys/kernel/btf/vmlinux libbpf: failed to get EHDR from /sys/kernel/btf/vmlinux For example, this could occur after cross-compiling a BTF-enabled kernel for a target with non-native endianness, which is currently unsupported. Check for correct endianness and emit a clearer error message: root:/# bpftool btf dump file /sys/kernel/btf/vmlinux libbpf: non-native BTF endianness is not supported Fixes: 94a1fedd63ed ("libbpf: Add btf__parse_raw() and generic btf__parse() APIs") Signed-off-by: Tony Ambardar <Tony.Ambardar@gmail.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: John Fastabend <john.fastabend@gmail.com> Acked-by: Andrii Nakryiko <andriin@fb.com> Link: https://lore.kernel.org/bpf/90f81508ecc57bc0da318e0fe0f45cfe49b17ea7.1600417359.git.Tony.Ambardar@gmail.com
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85367030 |
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18-Aug-2020 |
Andrii Nakryiko <andriin@fb.com> |
libbpf: Centralize poisoning and poison reallocarray() Most of libbpf source files already include libbpf_internal.h, so it's a good place to centralize identifier poisoning. So move kernel integer type poisoning there. And also add reallocarray to a poison list to prevent accidental use of it. libbpf_reallocarray() should be used universally instead. Signed-off-by: Andrii Nakryiko <andriin@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20200819013607.3607269-4-andriin@fb.com
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029258d7 |
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18-Aug-2020 |
Andrii Nakryiko <andriin@fb.com> |
libbpf: Remove any use of reallocarray() in libbpf 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
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28b93c64 |
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18-Aug-2020 |
Andrii Nakryiko <andriin@fb.com> |
libbpf: Clean up and improve CO-RE reloc logging Add logging of local/target type kind (struct/union/typedef/etc). Preserve unresolved root type ID (for cases of typedef). Improve the format of CO-RE reloc spec output format to contain only relevant and succinct info. Signed-off-by: Andrii Nakryiko <andriin@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20200818223921.2911963-3-andriin@fb.com
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44ad23df |
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13-Aug-2020 |
Andrii Nakryiko <andriin@fb.com> |
libbpf: Handle BTF pointer sizes more carefully With libbpf and BTF it is pretty common to have libbpf built for one architecture, while BTF information was generated for a different architecture (typically, but not always, BPF). In such case, the size of a pointer might differ betweem architectures. libbpf previously was always making an assumption that pointer size for BTF is the same as native architecture pointer size, but that breaks for cases where libbpf is built as 32-bit library, while BTF is for 64-bit architecture. To solve this, add heuristic to determine pointer size by searching for `long` or `unsigned long` integer type and using its size as a pointer size. Also, allow to override the pointer size with a new API btf__set_pointer_size(), for cases where application knows which pointer size should be used. User application can check what libbpf "guessed" by looking at the result of btf__pointer_size(). If it's not 0, then libbpf successfully determined a pointer size, otherwise native arch pointer size will be used. For cases where BTF is parsed from ELF file, use ELF's class (32-bit or 64-bit) to determine pointer size. Fixes: 8a138aed4a80 ("bpf: btf: Add BTF support to libbpf") Fixes: 351131b51c7a ("libbpf: add btf_dump API for BTF-to-C conversion") Signed-off-by: Andrii Nakryiko <andriin@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20200813204945.1020225-5-andriin@fb.com
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932ac54a |
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05-Aug-2020 |
Daniel T. Lee <danieltimlee@gmail.com> |
libbf: Fix uninitialized pointer at btf__parse_raw() Recently, from commit 94a1fedd63ed ("libbpf: Add btf__parse_raw() and generic btf__parse() APIs"), new API has been added to libbpf that allows to parse BTF from raw data file (btf__parse_raw()). The commit derives build failure of samples/bpf due to improper access of uninitialized pointer at btf_parse_raw(). btf.c: In function btf__parse_raw: btf.c:625:28: error: btf may be used uninitialized in this function 625 | return err ? ERR_PTR(err) : btf; | ~~~~~~~~~~~~~~~~~~~^~~~~ This commit fixes the build failure of samples/bpf by adding code of initializing btf pointer as NULL. Fixes: 94a1fedd63ed ("libbpf: Add btf__parse_raw() and generic btf__parse() APIs") Signed-off-by: Daniel T. Lee <danieltimlee@gmail.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: John Fastabend <john.fastabend@gmail.com> Link: https://lore.kernel.org/bpf/20200805223359.32109-1-danieltimlee@gmail.com
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94a1fedd6 |
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01-Aug-2020 |
Andrii Nakryiko <andriin@fb.com> |
libbpf: Add btf__parse_raw() and generic btf__parse() APIs Add public APIs to parse BTF from raw data file (e.g., /sys/kernel/btf/vmlinux), as well as generic btf__parse(), which will try to determine correct format, currently either raw or ELF. Signed-off-by: Andrii Nakryiko <andriin@fb.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Link: https://lore.kernel.org/bpf/20200802013219.864880-2-andriin@fb.com
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50450fc7 |
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29-Jul-2020 |
Andrii Nakryiko <andriin@fb.com> |
libbpf: Make destructors more robust by handling ERR_PTR(err) cases Most of libbpf "constructors" on failure return ERR_PTR(err) result encoded as a pointer. It's a common mistake to eventually pass such malformed pointers into xxx__destroy()/xxx__free() "destructors". So instead of fixing up clean up code in selftests and user programs, handle such error pointers in destructors themselves. This works beautifully for NULL pointers passed to destructors, so might as well just work for error pointers. Suggested-by: Song Liu <songliubraving@fb.com> 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/20200729232148.896125-1-andriin@fb.com
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5c3320d7 |
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09-Jul-2020 |
Andrii Nakryiko <andriin@fb.com> |
libbpf: Fix memory leak and optimize BTF sanitization Coverity's static analysis helpfully reported a memory leak introduced by 0f0e55d8247c ("libbpf: Improve BTF sanitization handling"). While fixing it, I realized that btf__new() already creates a memory copy, so there is no need to do this. So this patch also fixes misleading btf__new() signature to make data into a `const void *` input parameter. And it avoids unnecessary memory allocation and copy in BTF sanitization code altogether. Fixes: 0f0e55d8247c ("libbpf: Improve BTF sanitization handling") Signed-off-by: Andrii Nakryiko <andriin@fb.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Link: https://lore.kernel.org/bpf/20200710011023.1655008-1-andriin@fb.com
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81372e12 |
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07-Jul-2020 |
Andrii Nakryiko <andriin@fb.com> |
libbpf: Add btf__set_fd() for more control over loaded BTF FD Add setter for BTF FD to allow application more fine-grained control in more advanced scenarios. Storing BTF FD inside `struct btf` provides little benefit and probably would be better done differently (e.g., btf__load() could just return FD on success), but we are stuck with this due to backwards compatibility. The main problem is that it's impossible to load BTF and than free user-space memory, but keep FD intact, because `struct btf` assumes ownership of that FD upon successful load and will attempt to close it during btf__free(). To allow callers (e.g., libbpf itself for BTF sanitization) to have more control over this, add btf__set_fd() to allow to reset FD arbitrarily, if necessary. Signed-off-by: Andrii Nakryiko <andriin@fb.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Link: https://lore.kernel.org/bpf/20200708015318.3827358-3-andriin@fb.com
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8395f320 |
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25-Mar-2020 |
Stanislav Fomichev <sdf@google.com> |
libbpf: Don't allocate 16M for log buffer by default For each prog/btf load we allocate and free 16 megs of verifier buffer. On production systems it doesn't really make sense because the programs/btf have gone through extensive testing and (mostly) guaranteed to successfully load. Let's assume successful case by default and skip buffer allocation on the first try. If there is an error, start with BPF_LOG_BUF_SIZE and double it on each ENOSPC iteration. v3: * Return -ENOMEM when can't allocate log buffer (Andrii Nakryiko) v2: * Don't allocate the buffer at all on the first try (Andrii Nakryiko) Signed-off-by: Stanislav Fomichev <sdf@google.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Andrii Nakryiko <andriin@fb.com> Link: https://lore.kernel.org/bpf/20200325195521.112210-1-sdf@google.com
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fb2426ad |
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15-Jan-2020 |
Martin KaFai Lau <kafai@fb.com> |
libbpf: Expose bpf_find_kernel_btf as a LIBBPF_API This patch exposes bpf_find_kernel_btf() as a LIBBPF_API. It will be used in 'bpftool map dump' in a following patch to dump a map with btf_vmlinux_value_type_id set. bpf_find_kernel_btf() is renamed to libbpf_find_kernel_btf() and moved to btf.c. As <linux/kernel.h> is included, some of the max/min type casting needs to be fixed. Signed-off-by: Martin KaFai Lau <kafai@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Andrii Nakryiko <andriin@fb.com> Link: https://lore.kernel.org/bpf/20200115230031.1102305-1-kafai@fb.com
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1d1a3bcf |
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10-Jan-2020 |
Andrii Nakryiko <andriin@fb.com> |
libbpf: Poison kernel-only integer types It's been a recurring issue with types like u32 slipping into libbpf source code accidentally. This is not detected during builds inside kernel source tree, but becomes a compilation error in libbpf's Github repo. Libbpf is supposed to use only __{s,u}{8,16,32,64} typedefs, so poison {s,u}{8,16,32,64} explicitly in every .c file. Doing that in a bit more centralized way, e.g., inside libbpf_internal.h breaks selftests, which are both using kernel u32 and libbpf_internal.h. This patch also fixes a new u32 occurence in libbpf.c, added recently. Fixes: 590a00888250 ("bpf: libbpf: Add STRUCT_OPS support") 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/20200110181916.271446-1-andriin@fb.com
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a79ac2d1 |
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16-Dec-2019 |
Prashant Bhole <prashantbhole.linux@gmail.com> |
libbpf: Fix build by renaming variables In btf__align_of() variable name 't' is shadowed by inner block declaration of another variable with same name. Patch renames variables in order to fix it. CC sharedobjs/btf.o btf.c: In function ‘btf__align_of’: btf.c:303:21: error: declaration of ‘t’ shadows a previous local [-Werror=shadow] 303 | int i, align = 1, t; | ^ btf.c:283:25: note: shadowed declaration is here 283 | const struct btf_type *t = btf__type_by_id(btf, id); | Fixes: 3d208f4ca111 ("libbpf: Expose btf__align_of() API") Signed-off-by: Prashant Bhole <prashantbhole.linux@gmail.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Tested-by: Toke Høiland-Jørgensen <toke@redhat.com> Link: https://lore.kernel.org/bpf/20191216082738.28421-1-prashantbhole.linux@gmail.com
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166750bc |
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13-Dec-2019 |
Andrii Nakryiko <andriin@fb.com> |
libbpf: Support libbpf-provided extern variables 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
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3d208f4c |
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13-Dec-2019 |
Andrii Nakryiko <andriin@fb.com> |
libbpf: Expose btf__align_of() API Expose BTF API that calculates type alignment requirements. Signed-off-by: Andrii Nakryiko <andriin@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20191214014341.3442258-7-andriin@fb.com
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1442e287 |
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14-Nov-2019 |
Alexei Starovoitov <ast@kernel.org> |
libbpf: Introduce btf__find_by_name_kind() Introduce btf__find_by_name_kind() helper to search BTF by name and kind, since name alone can be ambiguous. Signed-off-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Song Liu <songliubraving@fb.com> Acked-by: Andrii Nakryiko <andriin@fb.com> Link: https://lore.kernel.org/bpf/20191114185720.1641606-6-ast@kernel.org
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994021a7 |
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06-Nov-2019 |
Andrii Nakryiko <andriin@fb.com> |
libbpf: Make btf__resolve_size logic always check size error condition Perform size check always in btf__resolve_size. Makes the logic a bit more robust against corrupted BTF and silences LGTM/Coverity complaining about always true (size < 0) check. Fixes: 69eaab04c675 ("btf: extract BTF type size calculation") Signed-off-by: Andrii Nakryiko <andriin@fb.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Link: https://lore.kernel.org/bpf/20191107020855.3834758-5-andriin@fb.com
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be18010e |
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20-Oct-2019 |
Kefeng Wang <wangkefeng.wang@huawei.com> |
tools, bpf: Rename pr_warning to pr_warn to align with kernel logging For kernel logging macros, pr_warning() is completely removed and replaced by pr_warn(). By using pr_warn() in tools/lib/bpf/ for symmetry to kernel logging macros, we could eventually drop the use of pr_warning() in the whole kernel tree. Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Reviewed-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Acked-by: Andrii Nakryiko <andriin@fb.com> Link: https://lore.kernel.org/bpf/20191021055532.185245-1-wangkefeng.wang@huawei.com
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#
511bb008 |
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15-Oct-2019 |
Andrii Nakryiko <andriin@fb.com> |
libbpf: Update BTF reloc support to latest Clang format BTF offset reloc was generalized in recent Clang into field relocation, capturing extra u32 field, specifying what aspect of captured field needs to be relocated. This changes .BTF.ext's record size for this relocation from 12 bytes to 16 bytes. Given these format changes happened in Clang before official released version, it's ok to not support outdated 12-byte record size w/o breaking ABI. Signed-off-by: Andrii Nakryiko <andriin@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20191015182849.3922287-2-andriin@fb.com
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4cedc0da |
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07-Aug-2019 |
Andrii Nakryiko <andriin@fb.com> |
libbpf: add .BTF.ext offset relocation section loading Add support for BPF CO-RE offset relocations. Add section/record iteration macros for .BTF.ext. These macro are useful for iterating over each .BTF.ext record, either for dumping out contents or later for BPF CO-RE relocation handling. To enable other parts of libbpf to work with .BTF.ext contents, moved a bunch of type definitions into libbpf_internal.h. Signed-off-by: Andrii Nakryiko <andriin@fb.com> Acked-by: Song Liu <songliubraving@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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b03bc685 |
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07-Aug-2019 |
Andrii Nakryiko <andriin@fb.com> |
libbpf: convert libbpf code to use new btf helpers Simplify code by relying on newly added BTF helper functions. Signed-off-by: Andrii Nakryiko <andriin@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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cdb2f920 |
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19-Jul-2019 |
Arnaldo Carvalho de Melo <acme@redhat.com> |
libbpf: Fix endianness macro usage for some compilers Using endian.h and its endianness macros makes this code build in a wider range of compilers, as some don't have those macros (__BYTE_ORDER__, __ORDER_LITTLE_ENDIAN__, __ORDER_BIG_ENDIAN__), so use instead endian.h's macros (__BYTE_ORDER, __LITTLE_ENDIAN, __BIG_ENDIAN) which makes this code even shorter :-) Acked-by: Andrii Nakryiko <andriin@fb.com> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Alexei Starovoitov <ast@kernel.org> Cc: Daniel Borkmann <daniel@iogearbox.net> Cc: Jiri Olsa <jolsa@kernel.org> Cc: Namhyung Kim <namhyung@kernel.org> Fixes: 12ef5634a855 ("libbpf: simplify endianness check") Fixes: e6c64855fd7a ("libbpf: add btf__parse_elf API to load .BTF and .BTF.ext") Link: https://lkml.kernel.org/n/tip-eep5n8vgwcdphw3uc058k03u@git.kernel.org Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
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d7fe74f9 |
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17-Jun-2019 |
Andrii Nakryiko <andriin@fb.com> |
libbpf: add common min/max macro to libbpf_internal.h Multiple files in libbpf redefine their own definitions for min/max. Let's define them in libbpf_internal.h and use those everywhere. Signed-off-by: Andrii Nakryiko <andriin@fb.com> Acked-by: Song Liu <songliubraving@fb.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
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2fc3fc0b |
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24-May-2019 |
Andrii Nakryiko <andriin@fb.com> |
libbpf: switch btf_dedup() to hashmap for dedup table Utilize libbpf's hashmap as a multimap fof dedup_table implementation. Signed-off-by: Andrii Nakryiko <andriin@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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e6c64855 |
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24-May-2019 |
Andrii Nakryiko <andriin@fb.com> |
libbpf: add btf__parse_elf API to load .BTF and .BTF.ext Loading BTF and BTF.ext from ELF file is a common need. Instead of requiring every user to re-implement it, let's provide this API from libbpf itself. It's mostly copy/paste from `bpftool btf dump` implementation, which will be switched to libbpf's version in next patch. btf__parse_elf allows to load BTF and optionally BTF.ext. This is also useful for tests that need to load/work with BTF, loaded from test ELF files. Signed-off-by: Andrii Nakryiko <andriin@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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d72386fe |
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15-May-2019 |
Andrii Nakryiko <andriin@fb.com> |
libbpf: move logging helpers into libbpf_internal.h libbpf_util.h header was recently exposed as public as a dependency of xsk.h. In addition to memory barriers, it contained logging helpers, which are not supposed to be exposed. This patch moves those into libbpf_internal.h, which is kept as an internal header. Cc: Stanislav Fomichev <sdf@google.com> Cc: Daniel Borkmann <daniel@iogearbox.net> Fixes: 7080da890984 ("libbpf: add libbpf_util.h to header install.") Signed-off-by: Andrii Nakryiko <andriin@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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189cf5a4 |
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15-Apr-2019 |
Andrii Nakryiko <andriin@fb.com> |
btf: add support for VAR and DATASEC in btf_dedup() This patch adds support for VAR and DATASEC in btf_dedup(). VAR/DATASEC are never deduplicated, but they need to be processed anyway as types they refer to might need to be remapped due to deduplication and compaction. Cc: Daniel Borkmann <daniel@iogearbox.net> Cc: Yonghong Song <yhs@fb.com> Cc: Alexei Starovoitov <ast@fb.com> Signed-off-by: Andrii Nakryiko <andriin@fb.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
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#
1713d68b |
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09-Apr-2019 |
Daniel Borkmann <daniel@iogearbox.net> |
bpf, libbpf: add support for BTF Var and DataSec This adds libbpf support for BTF Var and DataSec kinds. Main point here is that libbpf needs to do some preparatory work before the whole BTF object can be loaded into the kernel, that is, fixing up of DataSec size taken from the ELF section size and non-static variable offset which needs to be taken from the ELF's string section. Upstream LLVM doesn't fix these up since at time of BTF emission it is too early in the compilation process thus this information isn't available yet, hence loader needs to take care of it. Note, deduplication handling has not been in the scope of this work and needs to be addressed in a future commit. Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Link: https://reviews.llvm.org/D59441 Acked-by: Martin KaFai Lau <kafai@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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#
9ec71c1c |
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26-Mar-2019 |
Andrii Nakryiko <andriin@fb.com> |
libbpf: fix btf_dedup equivalence check handling of different kinds btf_dedup_is_equiv() used to compare btf_type->info fields, before doing kind-specific equivalence check. This comparsion implicitly verified that candidate and canonical types are of the same kind. With enum fwd resolution logic this check couldn't be done generically anymore, as for enums info contains vlen, which differs between enum fwd and fully-defined enum, so this check was subsumed by kind-specific equivalence checks. This change caused btf_dedup_is_equiv() to let through VOID vs other types check to reach switch, which was never meant to be handing VOID kind, as VOID kind is always pre-resolved to itself and is only equivalent to itself, which is checked early in btf_dedup_is_equiv(). This change adds back BTF kind equality check in place of more generic btf_type->info check, still defering further kind-specific checks to a per-kind switch. Fixes: 9768095ba97c ("btf: resolve enum fwds in btf_dedup") Signed-off-by: Andrii Nakryiko <andriin@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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9768095b |
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10-Mar-2019 |
Andrii Nakryiko <andriin@fb.com> |
btf: resolve enum fwds in btf_dedup GCC and clang support enum forward declarations as an extension. Such forward-declared enums will be represented as normal BTF_KIND_ENUM types with vlen=0. This patch adds ability to resolve such enums to their corresponding fully defined enums. This helps to avoid duplicated BTF type graphs which only differ by some types referencing forward-declared enum vs full enum. One such example in kernel is enum irqchip_irq_state, defined in include/linux/interrupt.h and forward-declared in include/linux/irq.h. This causes entire struct task_struct and all referenced types to be duplicated in btf_dedup output. This patch eliminates such duplication cases. Signed-off-by: Andrii Nakryiko <andriin@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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#
91097fbe |
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28-Feb-2019 |
Andrii Nakryiko <andriin@fb.com> |
btf: fix bug with resolving STRUCT/UNION into corresponding FWD When checking available canonical candidates for struct/union algorithm utilizes btf_dedup_is_equiv to determine if candidate is suitable. This check is not enough when candidate is corresponding FWD for that struct/union, because according to equivalence logic they are equivalent. When it so happens that FWD and STRUCT/UNION end in hashing to the same bucket, it's possible to create remapping loop from FWD to STRUCT and STRUCT to same FWD, which will cause btf_dedup() to loop forever. This patch fixes the issue by additionally checking that type and canonical candidate are strictly equal (utilizing btf_equal_struct). Fixes: d5caef5b5655 ("btf: add BTF types deduplication algorithm") Reported-by: Arnaldo Carvalho de Melo <acme@redhat.com> Signed-off-by: Andrii Nakryiko <andriin@fb.com> Acked-by: Song Liu <songliubraving@fb.com> Acked-by: Yonghong Song <yhs@fb.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
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51edf5f6 |
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28-Feb-2019 |
Andrii Nakryiko <andriin@fb.com> |
btf: allow to customize dedup hash table size Default size of dedup table (16k) is good enough for most binaries, even typical vmlinux images. But there are cases of binaries with huge amount of BTF types (e.g., allyesconfig variants of kernel), which benefit from having bigger dedup table size to lower amount of unnecessary hash collisions. Tools like pahole, thus, can tune this parameter to reach optimal performance. This change also serves double purpose of allowing tests to force hash collisions to test some corner cases, used in follow up patch. Signed-off-by: Andrii Nakryiko <andriin@fb.com> Acked-by: Yonghong Song <yhs@fb.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
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3d8669e6 |
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28-Feb-2019 |
Dan Carpenter <dan.carpenter@oracle.com> |
tools/libbpf: signedness bug in btf_dedup_ref_type() The "ref_type_id" variable needs to be signed for the error handling to work. Fixes: d5caef5b5655 ("btf: add BTF types deduplication algorithm") Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com> Acked-by: Andrii Nakryiko <andriin@fb.com> Acked-by: Song Liu <songliubraving@fb.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
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5aab392c |
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15-Feb-2019 |
Andrii Nakryiko <andriin@fb.com> |
tools/libbpf: support bigger BTF data sizes While it's understandable why kernel limits number of BTF types to 65535 and size of string section to 64KB, in libbpf as user-space library it's too restrictive. E.g., pahole converting DWARF to BTF type information for Linux kernel generates more than 3 million BTF types and more than 3MB of strings, before deduplication. So to allow btf__dedup() to do its work, we need to be able to load bigger BTF sections using btf__new(). Singed-off-by: Andrii Nakryiko <andriin@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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1ad9cbb8 |
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13-Feb-2019 |
Andrii Nakryiko <andriin@fb.com> |
tools/bpf: replace bzero with memset bzero() call is deprecated and superseded by memset(). Signed-off-by: Andrii Nakryiko <andriin@fb.com> Reported-by: David Laight <david.laight@aculab.com> Acked-by: Martin KaFai Lau <kafai@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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49b57e0d |
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08-Feb-2019 |
Andrii Nakryiko <andriin@fb.com> |
tools/bpf: remove btf__get_strings() superseded by raw data API Now that we have btf__get_raw_data() it's trivial for tests to iterate over all strings for testing purposes, which eliminates the need for btf__get_strings() API. Signed-off-by: Andrii Nakryiko <andriin@fb.com> Acked-by: Yonghong Song <yhs@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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ae4ab4b4 |
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08-Feb-2019 |
Andrii Nakryiko <andriin@fb.com> |
btf: expose API to work with raw btf_ext data This patch changes struct btf_ext to retain original data in sequential block of memory, which makes it possible to expose btf_ext__get_raw_data() interface similar to btf__get_raw_data(), allowing users of libbpf to get access to raw representation of .BTF.ext section. Signed-off-by: Andrii Nakryiko <andriin@fb.com> Acked-by: Yonghong Song <yhs@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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02c87446 |
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08-Feb-2019 |
Andrii Nakryiko <andriin@fb.com> |
btf: expose API to work with raw btf data This patch exposes new API btf__get_raw_data() that allows to get a copy of raw BTF data out of struct btf. This is useful for external programs that need to manipulate raw data, e.g., pahole using btf__dedup() to deduplicate BTF type info and then writing it back to file. Signed-off-by: Andrii Nakryiko <andriin@fb.com> Acked-by: Song Liu <songliubraving@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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d29d87f7 |
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08-Feb-2019 |
Andrii Nakryiko <andriin@fb.com> |
btf: separate btf creation and loading 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>
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62b8cea6 |
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07-Feb-2019 |
Andrii Nakryiko <andriin@fb.com> |
tools/bpf: add missing strings.h include Few files in libbpf are using bzero() function (defined in strings.h header), but don't include corresponding header. When libbpf is added as a dependency to pahole, this undeterministically causes warnings on some machines: bpf.c:225:2: warning: implicit declaration of function 'bzero' [-Wimplicit-function-declaration] bzero(&attr, sizeof(attr)); ^~~~~ Signed-off-by: Andrii Nakryiko <andriin@fb.com> Reported-by: Arnaldo Carvalho de Melo <acme@redhat.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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f7748e29 |
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05-Feb-2019 |
Yonghong Song <yhs@fb.com> |
tools/bpf: silence a libbpf unnecessary warning Commit 96408c43447a ("tools/bpf: implement libbpf btf__get_map_kv_tids() API function") refactored function bpf_map_find_btf_info() and moved bulk of implementation into btf.c as btf__get_map_kv_tids(). This change introduced a bug such that test_btf will print out the following warning although the test passed: BTF libbpf test[2] (test_btf_nokv.o): libbpf: map:btf_map container_name:____btf_map_btf_map cannot be found in BTF. Missing BPF_ANNOTATE_KV_PAIR? Previously, the error message is guarded with pr_debug(). Commit 96408c43447a changed it to pr_warning() and hence caused the warning. Restoring to pr_debug() for the message fixed the issue. Fixes: 96408c43447a ("tools/bpf: implement libbpf btf__get_map_kv_tids() API function") Signed-off-by: Yonghong Song <yhs@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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a6c109a6 |
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05-Feb-2019 |
Yonghong Song <yhs@fb.com> |
tools/bpf: add const qualifier to btf__get_map_kv_tids() map_name parameter 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>
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9c651127 |
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04-Feb-2019 |
Andrii Nakryiko <andriin@fb.com> |
selftests/btf: add initial BTF dedup tests 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>
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d5caef5b |
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04-Feb-2019 |
Andrii Nakryiko <andriin@fb.com> |
btf: add BTF types deduplication algorithm 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>
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69eaab04 |
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04-Feb-2019 |
Andrii Nakryiko <andriin@fb.com> |
btf: extract BTF type size calculation This pre-patch extracts calculation of amount of space taken by BTF type descriptor for later reuse by btf_dedup functionality. Signed-off-by: Andrii Nakryiko <andriin@fb.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
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96408c43 |
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04-Feb-2019 |
Yonghong Song <yhs@fb.com> |
tools/bpf: implement libbpf btf__get_map_kv_tids() API function 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>
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9d100a19 |
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01-Feb-2019 |
Yonghong Song <yhs@fb.com> |
tools/bpf: print out btf log at LIBBPF_WARN level Currently, the btf log is allocated and printed out in case of error at LIBBPF_DEBUG level. Such logs from kernel are very important for debugging. For example, bpf syscall BPF_PROG_LOAD command can get verifier logs back to user space. In function load_program() of libbpf.c, the log buffer is allocated unconditionally and printed out at pr_warning() level. Let us do the similar thing here for btf. Allocate buffer unconditionally and print out error logs at pr_warning() level. This can reduce one global function and optimize for common situations where pr_warning() is activated either by default or by user supplied debug output function. Signed-off-by: Yonghong Song <yhs@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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8461ef8b |
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01-Feb-2019 |
Yonghong Song <yhs@fb.com> |
tools/bpf: move libbpf pr_* debug print functions to headers 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>
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3d650141 |
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07-Dec-2018 |
Martin KaFai Lau <kafai@fb.com> |
bpf: libbpf: Add btf_line_info support to libbpf 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>
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f0187f0b |
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07-Dec-2018 |
Martin KaFai Lau <kafai@fb.com> |
bpf: libbpf: Refactor and bug fix on the bpf_func_info loading logic 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>
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84ecc1f9 |
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05-Dec-2018 |
Martin KaFai Lau <kafai@fb.com> |
bpf: Expect !info.func_info and insn_off name changes in test_btf/libbpf/bpftool Similar to info.jited_*, info.func_info could be 0 if bpf_dump_raw_ok() == false. This patch makes changes to test_btf and bpftool to expect info.func_info could be 0. This patch also makes the needed changes for s/insn_offset/insn_off/. Signed-off-by: Martin KaFai Lau <kafai@fb.com> Acked-by: Yonghong Song <yhs@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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1ad93ab1 |
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28-Nov-2018 |
David Miller <davem@davemloft.net> |
bpf: Fix various lib and testsuite build failures on 32-bit. Cannot cast a u64 to a pointer on 32-bit without an intervening (long) cast otherwise GCC warns. Signed-off-by: David S. Miller <davem@davemloft.net> Acked-by: Song Liu <songliubraving@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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1d2f44ca |
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23-Nov-2018 |
Martin KaFai Lau <kafai@fb.com> |
libbpf: Name changing for btf_get_from_id 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>
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d7f5b5e0 |
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19-Nov-2018 |
Yonghong Song <yhs@fb.com> |
tools/bpf: refactor to implement btf_get_from_id() in lib/bpf 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>
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2993e051 |
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19-Nov-2018 |
Yonghong Song <yhs@fb.com> |
tools/bpf: add support to read .BTF.ext sections 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>
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78a2540e |
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19-Nov-2018 |
Martin KaFai Lau <kafai@fb.com> |
tools/bpf: Add tests for BTF_KIND_FUNC_PROTO and BTF_KIND_FUNC This patch adds unit tests for BTF_KIND_FUNC_PROTO and BTF_KIND_FUNC to test_btf. Signed-off-by: Martin KaFai Lau <kafai@fb.com> Signed-off-by: Yonghong Song <yhs@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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1bc38b8f |
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05-Oct-2018 |
Alexei Starovoitov <ast@kernel.org> |
libbpf: relicense libbpf as LGPL-2.1 OR BSD-2-Clause 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>
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74682128 |
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05-Aug-2018 |
Martin KaFai Lau <kafai@fb.com> |
bpf: btf: Change tools/lib/bpf/btf to LGPL 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>
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6534770d |
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02-Aug-2018 |
Jakub Kicinski <kuba@kernel.org> |
tools: bpf: fix BTF code added twice to different trees 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>
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38d5d3b3 |
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24-Jul-2018 |
Martin KaFai Lau <kafai@fb.com> |
bpf: Introduce BPF_ANNOTATE_KV_PAIR 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>
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5b891af7 |
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24-Jul-2018 |
Martin KaFai Lau <kafai@fb.com> |
bpf: Replace [u]int32_t and [u]int64_t in libbpf 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>
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92b57121 |
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13-Jul-2018 |
Okash Khawaja <osk@fb.com> |
bpf: btf: export btf types and name by offset from lib 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>
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61746dbe |
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22-May-2018 |
Martin KaFai Lau <kafai@fb.com> |
bpf: btf: Add tests for the btf uapi changes This patch does the followings: 1. Modify libbpf and test_btf to reflect the uapi changes in btf 2. Add test for the btf_header changes 3. Add tests for array->index_type 4. Add err_str check to the tests 5. Fix a 4 bytes hole in "struct test #1" by swapping "m" and "n" Signed-off-by: Martin KaFai Lau <kafai@fb.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
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fbcf93eb |
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21-Apr-2018 |
Martin KaFai Lau <kafai@fb.com> |
bpf: btf: Clean up btf.h in uapi This patch cleans up btf.h in uapi: 1) Rename "name" to "name_off" to better reflect it is an offset to the string section instead of a char array. 2) Remove unused value BTF_FLAGS_COMPR and BTF_MAGIC_SWAP Suggested-by: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: Martin KaFai Lau <kafai@fb.com> Acked-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
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8a138aed |
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18-Apr-2018 |
Martin KaFai Lau <kafai@fb.com> |
bpf: btf: Add BTF support to libbpf 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>
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