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2021-12-10libbpf: Add OPTS-based bpf_btf_load() APIAndrii Nakryiko
Similar to previous bpf_prog_load() and bpf_map_create() APIs, add bpf_btf_load() API which is taking optional OPTS struct. Schedule bpf_load_btf() for deprecation in v0.8 ([0]). This makes naming consistent with BPF_BTF_LOAD command, sets up an API for extensibility in the future, moves options parameters (log-related fields) into optional options, and also allows to pass log_level directly. It also removes log buffer auto-allocation logic from low-level API (consistent with bpf_prog_load() behavior), but preserves a special treatment of log_level == 0 with non-NULL log_buf, which matches low-level bpf_prog_load() and high-level libbpf APIs for BTF and program loading behaviors. [0] Closes: https://github.com/libbpf/libbpf/issues/419 Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20211209193840.1248570-3-andrii@kernel.org
2021-12-10libbpf: Fix bpf_prog_load() log_buf logic for log_level 0Andrii Nakryiko
To unify libbpf APIs behavior w.r.t. log_buf and log_level, fix bpf_prog_load() to follow the same logic as bpf_btf_load() and high-level bpf_object__load() API will follow in the subsequent patches: - if log_level is 0 and non-NULL log_buf is provided by a user, attempt load operation initially with no log_buf and log_level set; - if successful, we are done, return new FD; - on error, retry the load operation with log_level bumped to 1 and log_buf set; this way verbose logging will be requested only when we are sure that there is a failure, but will be fast in the common/expected success case. Of course, user can still specify log_level > 0 from the very beginning to force log collection. 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/20211209193840.1248570-2-andrii@kernel.org
2021-12-06libbpf: Add doc comments in libbpf.hGrant Seltzer
This adds comments above functions in libbpf.h which document their uses. These comments are of a format that doxygen and sphinx can pick up and render. These are rendered by libbpf.readthedocs.org These doc comments are for: - bpf_object__open_file() - bpf_object__open_mem() - bpf_program__attach_uprobe() - bpf_program__attach_uprobe_opts() Signed-off-by: Grant Seltzer <grantseltzer@gmail.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20211206203709.332530-1-grantseltzer@gmail.com
2021-12-06libbpf: Fix trivial typohuangxuesen
Fix typo in comment from 'bpf_skeleton_map' to 'bpf_map_skeleton' and from 'bpf_skeleton_prog' to 'bpf_prog_skeleton'. Signed-off-by: huangxuesen <huangxuesen@kuaishou.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/1638755236-3851199-1-git-send-email-hxseverything@gmail.com
2021-12-03libbpf: Reduce bpf_core_apply_relo_insn() stack usage.Alexei Starovoitov
Reduce bpf_core_apply_relo_insn() stack usage and bump BPF_CORE_SPEC_MAX_LEN limit back to 64. Fixes: 29db4bea1d10 ("bpf: Prepare relo_core.c for kernel duty.") Signed-off-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20211203182836.16646-1-alexei.starovoitov@gmail.com
2021-12-02libbpf: Deprecate bpf_prog_load_xattr() APIAndrii Nakryiko
bpf_prog_load_xattr() is high-level API that's named as a low-level BPF_PROG_LOAD wrapper APIs, but it actually operates on struct bpf_object. It's badly and confusingly misnamed as it will load all the progs insige bpf_object, returning prog_fd of the very first BPF program. It also has a bunch of ad-hoc things like log_level override, map_ifindex auto-setting, etc. All this can be expressed more explicitly and cleanly through existing libbpf APIs. This patch marks bpf_prog_load_xattr() for deprecation in libbpf v0.8 ([0]). [0] Closes: https://github.com/libbpf/libbpf/issues/308 Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20211201232824.3166325-10-andrii@kernel.org
2021-12-02libbpf: Add API to get/set log_level at per-program levelAndrii Nakryiko
Add bpf_program__set_log_level() and bpf_program__log_level() to fetch and adjust log_level sent during BPF_PROG_LOAD command. This allows to selectively request more or less verbose output in BPF verifier log. Also bump libbpf version to 0.7 and make these APIs the first in v0.7. Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20211201232824.3166325-3-andrii@kernel.org
2021-12-02libbpf: Use __u32 fields in bpf_map_create_optsAndrii Nakryiko
Corresponding Linux UAPI struct uses __u32, not int, so keep it consistent. Fixes: 992c4225419a ("libbpf: Unify low-level map creation APIs w/ new bpf_map_create()") Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20211201232824.3166325-2-andrii@kernel.org
2021-12-02libbpf: Clean gen_loader's attach kind.Alexei Starovoitov
The gen_loader has to clear attach_kind otherwise the programs without attach_btf_id will fail load if they follow programs with attach_btf_id. Fixes: 67234743736a ("libbpf: Generate loader program out of BPF ELF file.") 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/20211201181040.23337-12-alexei.starovoitov@gmail.com
2021-12-02libbpf: Support init of inner maps in light skeleton.Alexei Starovoitov
Add ability to initialize inner maps in light skeleton. 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/20211201181040.23337-11-alexei.starovoitov@gmail.com
2021-12-02libbpf: Use CO-RE in the kernel in light skeleton.Alexei Starovoitov
Without lskel the CO-RE relocations are processed by libbpf before any other work is done. Instead, when lskel is needed, remember relocation as RELO_CORE kind. Then when loader prog is generated for a given bpf program pass CO-RE relos of that program to gen loader via bpf_gen__record_relo_core(). The gen loader will remember them as-is and pass it later as-is into the kernel. The normal libbpf flow is to process CO-RE early before call relos happen. In case of gen_loader the core relos have to be added to other relos to be copied together when bpf static function is appended in different places to other main bpf progs. During the copy the append_subprog_relos() will adjust insn_idx for normal relos and for RELO_CORE kind too. When that is done each struct reloc_desc has good relos for specific main prog. 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/20211201181040.23337-10-alexei.starovoitov@gmail.com
2021-12-02libbpf: Cleanup struct bpf_core_cand.Andrii Nakryiko
Remove two redundant fields from struct bpf_core_cand. Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20211201181040.23337-8-alexei.starovoitov@gmail.com
2021-12-02bpf: Pass a set of bpf_core_relo-s to prog_load command.Alexei Starovoitov
struct bpf_core_relo is generated by llvm and processed by libbpf. It's a de-facto uapi. With CO-RE in the kernel the struct bpf_core_relo becomes uapi de-jure. Add an ability to pass a set of 'struct bpf_core_relo' to prog_load command and let the kernel perform CO-RE relocations. Note the struct bpf_line_info and struct bpf_func_info have the same layout when passed from LLVM to libbpf and from libbpf to the kernel except "insn_off" fields means "byte offset" when LLVM generates it. Then libbpf converts it to "insn index" to pass to the kernel. The struct bpf_core_relo's "insn_off" field is always "byte offset". 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/20211201181040.23337-6-alexei.starovoitov@gmail.com
2021-12-02bpf: Define enum bpf_core_relo_kind as uapi.Alexei Starovoitov
enum bpf_core_relo_kind is generated by llvm and processed by libbpf. It's a de-facto uapi. With CO-RE in the kernel the bpf_core_relo_kind values become uapi de-jure. Also rename them with BPF_CORE_ prefix to distinguish from conflicting names in bpf_core_read.h. The enums bpf_field_info_kind, bpf_type_id_kind, bpf_type_info_kind, bpf_enum_value_kind are passing different values from bpf program into llvm. 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/20211201181040.23337-5-alexei.starovoitov@gmail.com
2021-12-02bpf: Prepare relo_core.c for kernel duty.Alexei Starovoitov
Make relo_core.c to be compiled for the kernel and for user space libbpf. Note the patch is reducing BPF_CORE_SPEC_MAX_LEN from 64 to 32. This is the maximum number of nested structs and arrays. For example: struct sample { int a; struct { int b[10]; }; }; struct sample *s = ...; int *y = &s->b[5]; This field access is encoded as "0:1:0:5" and spec len is 4. The follow up patch might bump it back to 64. 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/20211201181040.23337-4-alexei.starovoitov@gmail.com
2021-12-02libbpf: Replace btf__type_by_id() with btf_type_by_id().Alexei Starovoitov
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
2021-11-30libbpf: Avoid reload of imm for weak, unresolved, repeating ksymKumar Kartikeya Dwivedi
Alexei pointed out that we can use BPF_REG_0 which already contains imm from move_blob2blob computation. Note that we now compare the second insn's imm, but this should not matter, since both will be zeroed out for the error case for the insn populated earlier. Suggested-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Acked-by: Song Liu <songliubraving@fb.com> Link: https://lore.kernel.org/bpf/20211122235733.634914-4-memxor@gmail.com
2021-11-30libbpf: Avoid double stores for success/failure case of ksym relocationsKumar Kartikeya Dwivedi
Instead, jump directly to success case stores in case ret >= 0, else do the default 0 value store and jump over the success case. This is better in terms of readability. Readjust the code for kfunc relocation as well to follow a similar pattern, also leads to easier to follow code now. Suggested-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Acked-by: Song Liu <songliubraving@fb.com> Link: https://lore.kernel.org/bpf/20211122235733.634914-3-memxor@gmail.com
2021-11-30libbpf: Remove duplicate assignmentsMehrdad Arshad Rad
There is a same action when load_attr.attach_btf_id is initialized. Signed-off-by: Mehrdad Arshad Rad <arshad.rad@gmail.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Link: https://lore.kernel.org/bpf/20211128193337.10628-1-arshad.rad@gmail.com
2021-11-29libbpf: Silence uninitialized warning/error in btf_dump_dump_type_dataAlan Maguire
When compiling libbpf with gcc 4.8.5, we see: CC staticobjs/btf_dump.o btf_dump.c: In function ‘btf_dump_dump_type_data.isra.24’: btf_dump.c:2296:5: error: ‘err’ may be used uninitialized in this function [-Werror=maybe-uninitialized] if (err < 0) ^ cc1: all warnings being treated as errors make: *** [staticobjs/btf_dump.o] Error 1 While gcc 4.8.5 is too old to build the upstream kernel, it's possible it could be used to build standalone libbpf which suffers from the same problem. Silence the error by initializing 'err' to 0. The warning/error seems to be a false positive since err is set early in the function. Regardless we shouldn't prevent libbpf from building for this. Fixes: 920d16af9b42 ("libbpf: BTF dumper support for typed data") Signed-off-by: Alan Maguire <alan.maguire@oracle.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/1638180040-8037-1-git-send-email-alan.maguire@oracle.com
2021-11-28libbpf: Support static initialization of BPF_MAP_TYPE_PROG_ARRAYHengqi Chen
Support static initialization of BPF_MAP_TYPE_PROG_ARRAY with a syntax similar to map-in-map initialization ([0]): SEC("socket") int tailcall_1(void *ctx) { return 0; } struct { __uint(type, BPF_MAP_TYPE_PROG_ARRAY); __uint(max_entries, 2); __uint(key_size, sizeof(__u32)); __array(values, int (void *)); } prog_array_init SEC(".maps") = { .values = { [1] = (void *)&tailcall_1, }, }; Here's the relevant part of libbpf debug log showing what's going on with prog-array initialization: libbpf: sec '.relsocket': collecting relocation for section(3) 'socket' libbpf: sec '.relsocket': relo #0: insn #2 against 'prog_array_init' libbpf: prog 'entry': found map 0 (prog_array_init, sec 4, off 0) for insn #0 libbpf: .maps relo #0: for 3 value 0 rel->r_offset 32 name 53 ('tailcall_1') libbpf: .maps relo #0: map 'prog_array_init' slot [1] points to prog 'tailcall_1' libbpf: map 'prog_array_init': created successfully, fd=5 libbpf: map 'prog_array_init': slot [1] set to prog 'tailcall_1' fd=6 [0] Closes: https://github.com/libbpf/libbpf/issues/354 Signed-off-by: Hengqi Chen <hengqi.chen@gmail.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20211128141633.502339-2-hengqi.chen@gmail.com
2021-11-26bpf, mips: Fix build errors about __NR_bpf undeclaredTiezhu Yang
Add the __NR_bpf definitions to fix the following build errors for mips: $ cd tools/bpf/bpftool $ make [...] bpf.c:54:4: error: #error __NR_bpf not defined. libbpf does not support your arch. # error __NR_bpf not defined. libbpf does not support your arch. ^~~~~ bpf.c: In function ‘sys_bpf’: bpf.c:66:17: error: ‘__NR_bpf’ undeclared (first use in this function); did you mean ‘__NR_brk’? return syscall(__NR_bpf, cmd, attr, size); ^~~~~~~~ __NR_brk [...] In file included from gen_loader.c:15:0: skel_internal.h: In function ‘skel_sys_bpf’: skel_internal.h:53:17: error: ‘__NR_bpf’ undeclared (first use in this function); did you mean ‘__NR_brk’? return syscall(__NR_bpf, cmd, attr, size); ^~~~~~~~ __NR_brk We can see the following generated definitions: $ grep -r "#define __NR_bpf" arch/mips arch/mips/include/generated/uapi/asm/unistd_o32.h:#define __NR_bpf (__NR_Linux + 355) arch/mips/include/generated/uapi/asm/unistd_n64.h:#define __NR_bpf (__NR_Linux + 315) arch/mips/include/generated/uapi/asm/unistd_n32.h:#define __NR_bpf (__NR_Linux + 319) The __NR_Linux is defined in arch/mips/include/uapi/asm/unistd.h: $ grep -r "#define __NR_Linux" arch/mips arch/mips/include/uapi/asm/unistd.h:#define __NR_Linux 4000 arch/mips/include/uapi/asm/unistd.h:#define __NR_Linux 5000 arch/mips/include/uapi/asm/unistd.h:#define __NR_Linux 6000 That is to say, __NR_bpf is: 4000 + 355 = 4355 for mips o32, 6000 + 319 = 6319 for mips n32, 5000 + 315 = 5315 for mips n64. So use the GCC pre-defined macro _ABIO32, _ABIN32 and _ABI64 [1] to define the corresponding __NR_bpf. This patch is similar with commit bad1926dd2f6 ("bpf, s390: fix build for libbpf and selftest suite"). [1] https://gcc.gnu.org/git/?p=gcc.git;a=blob;f=gcc/config/mips/mips.h#l549 Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Link: https://lore.kernel.org/bpf/1637804167-8323-1-git-send-email-yangtiezhu@loongson.cn
2021-11-26libbpf: Fix using invalidated memory in bpf_linkerAndrii Nakryiko
add_dst_sec() can invalidate bpf_linker's section index making dst_symtab pointer pointing into unallocated memory. Reinitialize dst_symtab pointer on each iteration to make sure it's always valid. Fixes: faf6ed321cf6 ("libbpf: Add BPF static linker APIs") Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Link: https://lore.kernel.org/bpf/20211124002325.1737739-7-andrii@kernel.org
2021-11-26libbpf: Fix glob_syms memory leak in bpf_linkerAndrii Nakryiko
glob_syms array wasn't freed on bpf_link__free(). Fix that. Fixes: a46349227cd8 ("libbpf: Add linker extern resolution support for functions and global variables") Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Link: https://lore.kernel.org/bpf/20211124002325.1737739-6-andrii@kernel.org
2021-11-26libbpf: Don't call libc APIs with NULL pointersAndrii Nakryiko
Sanitizer complains about qsort(), bsearch(), and memcpy() being called with NULL pointer. This can only happen when the associated number of elements is zero, so no harm should be done. But still prevent this from happening to keep sanitizer runs clean from extra noise. Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Link: https://lore.kernel.org/bpf/20211124002325.1737739-5-andrii@kernel.org
2021-11-26libbpf: Fix potential misaligned memory access in btf_ext__new()Andrii Nakryiko
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
2021-11-25libbpf: Prevent deprecation warnings in xsk.cAndrii Nakryiko
xsk.c is using own APIs that are marked for deprecation internally. Given xsk.c and xsk.h will be gone in libbpf 1.0, there is no reason to do public vs internal function split just to avoid deprecation warnings. So just add a pragma to silence deprecation warnings (until the code is removed completely). Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Link: https://lore.kernel.org/bpf/20211124193233.3115996-4-andrii@kernel.org
2021-11-25libbpf: Use bpf_map_create() consistently internallyAndrii Nakryiko
Remove all the remaining uses of to-be-deprecated bpf_create_map*() APIs. Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Link: https://lore.kernel.org/bpf/20211124193233.3115996-3-andrii@kernel.org
2021-11-25libbpf: Unify low-level map creation APIs w/ new bpf_map_create()Andrii Nakryiko
Mark the entire zoo of low-level map creation APIs for deprecation in libbpf 0.7 ([0]) and introduce a new bpf_map_create() API that is OPTS-based (and thus future-proof) and matches the BPF_MAP_CREATE command name. While at it, ensure that gen_loader sends map_extra field. Also remove now unneeded btf_key_type_id/btf_value_type_id logic that libbpf is doing anyways. [0] Closes: https://github.com/libbpf/libbpf/issues/282 Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Link: https://lore.kernel.org/bpf/20211124193233.3115996-2-andrii@kernel.org
2021-11-25libbpf: Load global data maps lazily on legacy kernelsAndrii Nakryiko
Load global data maps lazily, if kernel is too old to support global data. Make sure that programs are still correct by detecting if any of the to-be-loaded programs have relocation against any of such maps. This allows to solve the issue ([0]) with bpf_printk() and Clang generating unnecessary and unreferenced .rodata.strX.Y sections, but it also goes further along the CO-RE lines, allowing to have a BPF object in which some code can work on very old kernels and relies only on BPF maps explicitly, while other BPF programs might enjoy global variable support. If such programs are correctly set to not load at runtime on old kernels, bpf_object will load and function correctly now. [0] https://lore.kernel.org/bpf/CAK-59YFPU3qO+_pXWOH+c1LSA=8WA1yabJZfREjOEXNHAqgXNg@mail.gmail.com/ Fixes: aed659170a31 ("libbpf: Support multiple .rodata.* and .data.* BPF maps") Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Song Liu <songliubraving@fb.com> Link: https://lore.kernel.org/bpf/20211123200105.387855-1-andrii@kernel.org
2021-11-19libbpf: Change bpf_program__set_extra_flags to bpf_program__set_flagsFlorent Revest
bpf_program__set_extra_flags has just been introduced so we can still change it without breaking users. This new interface is a bit more flexible (for example if someone wants to clear a flag). Signed-off-by: Florent Revest <revest@chromium.org> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20211119180035.1396139-1-revest@chromium.org
2021-11-19libbpf: Accommodate DWARF/compiler bug with duplicated structsAndrii Nakryiko
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
2021-11-19libbpf: Add runtime APIs to query libbpf versionAndrii Nakryiko
Libbpf provided LIBBPF_MAJOR_VERSION and LIBBPF_MINOR_VERSION macros to check libbpf version at compilation time. This doesn't cover all the needs, though, because version of libbpf that application is compiled against doesn't necessarily match the version of libbpf at runtime, especially if libbpf is used as a shared library. Add libbpf_major_version() and libbpf_minor_version() returning major and minor versions, respectively, as integers. Also add a convenience libbpf_version_string() for various tooling using libbpf to print out libbpf version in a human-readable form. Currently it will return "v0.6", but in the future it can contains some extra information, so the format itself is not part of a stable API and shouldn't be relied upon. Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: John Fastabend <john.fastabend@gmail.com> Acked-by: Toke Høiland-Jørgensen <toke@redhat.com> Link: https://lore.kernel.org/bpf/20211118174054.2699477-1-andrii@kernel.org
2021-11-18Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/netJakub Kicinski
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2021-11-16libbpf: Fix a couple of missed btf_type_tag handling in btf.cYonghong Song
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
2021-11-15Merge https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-nextJakub Kicinski
Daniel Borkmann says: ==================== pull-request: bpf-next 2021-11-15 We've added 72 non-merge commits during the last 13 day(s) which contain a total of 171 files changed, 2728 insertions(+), 1143 deletions(-). The main changes are: 1) Add btf_type_tag attributes to bring kernel annotations like __user/__rcu to BTF such that BPF verifier will be able to detect misuse, from Yonghong Song. 2) Big batch of libbpf improvements including various fixes, future proofing APIs, and adding a unified, OPTS-based bpf_prog_load() low-level API, from Andrii Nakryiko. 3) Add ingress_ifindex to BPF_SK_LOOKUP program type for selectively applying the programmable socket lookup logic to packets from a given netdev, from Mark Pashmfouroush. 4) Remove the 128M upper JIT limit for BPF programs on arm64 and add selftest to ensure exception handling still works, from Russell King and Alan Maguire. 5) Add a new bpf_find_vma() helper for tracing to map an address to the backing file such as shared library, from Song Liu. 6) Batch of various misc fixes to bpftool, fixing a memory leak in BPF program dump, updating documentation and bash-completion among others, from Quentin Monnet. 7) Deprecate libbpf bpf_program__get_prog_info_linear() API and migrate its users as the API is heavily tailored around perf and is non-generic, from Dave Marchevsky. 8) Enable libbpf's strict mode by default in bpftool and add a --legacy option as an opt-out for more relaxed BPF program requirements, from Stanislav Fomichev. 9) Fix bpftool to use libbpf_get_error() to check for errors, from Hengqi Chen. * https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next: (72 commits) bpftool: Use libbpf_get_error() to check error bpftool: Fix mixed indentation in documentation bpftool: Update the lists of names for maps and prog-attach types bpftool: Fix indent in option lists in the documentation bpftool: Remove inclusion of utilities.mak from Makefiles bpftool: Fix memory leak in prog_dump() selftests/bpf: Fix a tautological-constant-out-of-range-compare compiler warning selftests/bpf: Fix an unused-but-set-variable compiler warning bpf: Introduce btf_tracing_ids bpf: Extend BTF_ID_LIST_GLOBAL with parameter for number of IDs bpftool: Enable libbpf's strict mode by default docs/bpf: Update documentation for BTF_KIND_TYPE_TAG support selftests/bpf: Clarify llvm dependency with btf_tag selftest selftests/bpf: Add a C test for btf_type_tag selftests/bpf: Rename progs/tag.c to progs/btf_decl_tag.c selftests/bpf: Test BTF_KIND_DECL_TAG for deduplication selftests/bpf: Add BTF_KIND_TYPE_TAG unit tests selftests/bpf: Test libbpf API function btf__add_type_tag() bpftool: Support BTF_KIND_TYPE_TAG libbpf: Support BTF_KIND_TYPE_TAG ... ==================== Link: https://lore.kernel.org/r/20211115162008.25916-1-daniel@iogearbox.net Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2021-11-12libbpf: Perform map fd cleanup for gen_loader in case of errorKumar Kartikeya Dwivedi
Alexei reported a fd leak issue in gen loader (when invoked from bpftool) [0]. When adding ksym support, map fd allocation was moved from stack to loader map, however I missed closing these fds (relevant when cleanup label is jumped to on error). For the success case, the allocated fd is returned in loader ctx, hence this problem is not noticed. Make three changes, first MAX_USED_MAPS in MAX_FD_ARRAY_SZ instead of MAX_USED_PROGS, the braino was not a problem until now for this case as we didn't try to close map fds (otherwise use of it would have tried closing 32 additional fds in ksym btf fd range). Then, do a cleanup for all nr_maps fds in cleanup label code, so that in case of error all temporary map fds from bpf_gen__map_create are closed. Then, adjust the cleanup label to only generate code for the required number of program and map fds. To trim code for remaining program fds, lay out prog_fd array in stack in the end, so that we can directly skip the remaining instances. Still stack size remains same, since changing that would require changes in a lot of places (including adjustment of stack_off macro), so nr_progs_sz variable is only used to track required number of iterations (and jump over cleanup size calculated from that), stack offset calculation remains unaffected. The difference for test_ksyms_module.o is as follows: libbpf: //prog cleanup iterations: before = 34, after = 5 libbpf: //maps cleanup iterations: before = 64, after = 2 Also, move allocation of gen->fd_array offset to bpf_gen__init. Since offset can now be 0, and we already continue even if add_data returns 0 in case of failure, we do not need to distinguish between 0 offset and failure case 0, as we rely on bpf_gen__finish to check errors. We can also skip check for gen->fd_array in add_*_fd functions, since bpf_gen__init will take care of it. [0]: https://lore.kernel.org/bpf/CAADnVQJ6jSitKSNKyxOrUzwY2qDRX0sPkJ=VLGHuCLVJ=qOt9g@mail.gmail.com Fixes: 18f4fccbf314 ("libbpf: Update gen_loader to emit BTF_KIND_FUNC relocations") Reported-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20211112232022.899074-1-memxor@gmail.com
2021-11-11libbpf: Support BTF_KIND_TYPE_TAGYonghong Song
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
2021-11-11libbpf: Make perf_buffer__new() use OPTS-based interfaceAndrii Nakryiko
Add new variants of perf_buffer__new() and perf_buffer__new_raw() that use OPTS-based options for future extensibility ([0]). Given all the currently used API names are best fits, re-use them and use ___libbpf_override() approach and symbol versioning to preserve ABI and source code compatibility. struct perf_buffer_opts and struct perf_buffer_raw_opts are kept as well, but they are restructured such that they are OPTS-based when used with new APIs. For struct perf_buffer_raw_opts we keep few fields intact, so we have to also preserve the memory location of them both when used as OPTS and for legacy API variants. This is achieved with anonymous padding for OPTS "incarnation" of the struct. These pads can be eventually used for new options. [0] Closes: https://github.com/libbpf/libbpf/issues/311 Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20211111053624.190580-6-andrii@kernel.org
2021-11-11libbpf: Ensure btf_dump__new() and btf_dump_opts are future-proofAndrii Nakryiko
Change btf_dump__new() and corresponding struct btf_dump_ops structure to be extensible by using OPTS "framework" ([0]). Given we don't change the names, we use a similar approach as with bpf_prog_load(), but this time we ended up with two APIs with the same name and same number of arguments, so overloading based on number of arguments with ___libbpf_override() doesn't work. Instead, use "overloading" based on types. In this particular case, print callback has to be specified, so we detect which argument is a callback. If it's 4th (last) argument, old implementation of API is used by user code. If not, it must be 2nd, and thus new implementation is selected. The rest is handled by the same symbol versioning approach. btf_ext argument is dropped as it was never used and isn't necessary either. If in the future we'll need btf_ext, that will be added into OPTS-based struct btf_dump_opts. struct btf_dump_opts is reused for both old API and new APIs. ctx field is marked deprecated in v0.7+ and it's put at the same memory location as OPTS's sz field. Any user of new-style btf_dump__new() will have to set sz field and doesn't/shouldn't use ctx, as ctx is now passed along the callback as mandatory input argument, following the other APIs in libbpf that accept callbacks consistently. Again, this is quite ugly in implementation, but is done in the name of backwards compatibility and uniform and extensible future APIs (at the same time, sigh). And it will be gone in libbpf 1.0. [0] Closes: https://github.com/libbpf/libbpf/issues/283 Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20211111053624.190580-5-andrii@kernel.org
2021-11-11libbpf: Turn btf_dedup_opts into OPTS-based structAndrii Nakryiko
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
2021-11-11libbpf: Add ability to get/set per-program load flagsAndrii Nakryiko
Add bpf_program__flags() API to retrieve prog_flags that will be (or were) supplied to BPF_PROG_LOAD command. Also add bpf_program__set_extra_flags() API to allow to set *extra* flags, in addition to those determined by program's SEC() definition. Such flags are logically OR'ed with libbpf-derived flags. Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20211111051758.92283-2-andrii@kernel.org
2021-11-09libbpf: Compile using -std=gnu89Kumar Kartikeya Dwivedi
The minimum supported C standard version is C89, with use of GNU extensions, hence make sure to catch any instances that would break the build for this mode by passing -std=gnu89. Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20211105234243.390179-4-memxor@gmail.com
2021-11-07libbpf: Free up resources used by inner map definitionAndrii Nakryiko
It's not enough to just free(map->inner_map), as inner_map itself can have extra memory allocated, like map name. Fixes: 646f02ffdd49 ("libbpf: Add BTF-defined map-in-map support") Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Reviewed-by: Hengqi Chen <hengqi.chen@gmail.com> Link: https://lore.kernel.org/bpf/20211107165521.9240-3-andrii@kernel.org
2021-11-07libbpf: Remove deprecation attribute from struct bpf_prog_prep_resultAndrii Nakryiko
This deprecation annotation has no effect because for struct deprecation attribute has to be declared after struct definition. But instead of moving it to the end of struct definition, remove it. When deprecation will go in effect at libbpf v0.7, this deprecation attribute will cause libbpf's own source code compilation to trigger deprecation warnings, which is unavoidable because libbpf still has to support that API. So keep deprecation of APIs, but don't mark structs used in API as deprecated. Fixes: e21d585cb3db ("libbpf: Deprecate multi-instance bpf_program APIs") Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Dave Marchevsky <davemarchevsky@fb.com> Link: https://lore.kernel.org/bpf/20211103220845.2676888-8-andrii@kernel.org
2021-11-07libbpf: Stop using to-be-deprecated APIsAndrii Nakryiko
Remove all the internal uses of libbpf APIs that are slated to be deprecated in v0.7. Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20211103220845.2676888-6-andrii@kernel.org
2021-11-07libbpf: Remove internal use of deprecated bpf_prog_load() variantsAndrii Nakryiko
Remove all the internal uses of bpf_load_program_xattr(), which is slated for deprecation in v0.7. Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20211103220845.2676888-5-andrii@kernel.org
2021-11-07libbpf: Unify low-level BPF_PROG_LOAD APIs into bpf_prog_load()Andrii Nakryiko
Add a new unified OPTS-based low-level API for program loading, bpf_prog_load() ([0]). bpf_prog_load() accepts few "mandatory" parameters as input arguments (program type, name, license, instructions) and all the other optional (as in not required to specify for all types of BPF programs) fields into struct bpf_prog_load_opts. This makes all the other non-extensible APIs variant for BPF_PROG_LOAD obsolete and they are slated for deprecation in libbpf v0.7: - bpf_load_program(); - bpf_load_program_xattr(); - bpf_verify_program(). Implementation-wise, internal helper libbpf__bpf_prog_load is refactored to become a public bpf_prog_load() API. struct bpf_prog_load_params used internally is replaced by public struct bpf_prog_load_opts. Unfortunately, while conceptually all this is pretty straightforward, the biggest complication comes from the already existing bpf_prog_load() *high-level* API, which has nothing to do with BPF_PROG_LOAD command. We try really hard to have a new API named bpf_prog_load(), though, because it maps naturally to BPF_PROG_LOAD command. For that, we rename old bpf_prog_load() into bpf_prog_load_deprecated() and mark it as COMPAT_VERSION() for shared library users compiled against old version of libbpf. Statically linked users and shared lib users compiled against new version of libbpf headers will get "rerouted" to bpf_prog_deprecated() through a macro helper that decides whether to use new or old bpf_prog_load() based on number of input arguments (see ___libbpf_overload in libbpf_common.h). To test that existing bpf_prog_load()-using code compiles and works as expected, I've compiled and ran selftests as is. I had to remove (locally) selftest/bpf/Makefile -Dbpf_prog_load=bpf_prog_test_load hack because it was conflicting with the macro-based overload approach. I don't expect anyone else to do something like this in practice, though. This is testing-specific way to replace bpf_prog_load() calls with special testing variant of it, which adds extra prog_flags value. After testing I kept this selftests hack, but ensured that we use a new bpf_prog_load_deprecated name for this. This patch also marks bpf_prog_load() and bpf_prog_load_xattr() as deprecated. bpf_object interface has to be used for working with struct bpf_program. Libbpf doesn't support loading just a bpf_program. The silver lining is that when we get to libbpf 1.0 all these complication will be gone and we'll have one clean bpf_prog_load() low-level API with no backwards compatibility hackery surrounding it. [0] Closes: https://github.com/libbpf/libbpf/issues/284 Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20211103220845.2676888-4-andrii@kernel.org
2021-11-07libbpf: Pass number of prog load attempts explicitlyAndrii Nakryiko
Allow to control number of BPF_PROG_LOAD attempts from outside the sys_bpf_prog_load() helper. Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Dave Marchevsky <davemarchevsky@fb.com> Link: https://lore.kernel.org/bpf/20211103220845.2676888-3-andrii@kernel.org
2021-11-07libbpf: Rename DECLARE_LIBBPF_OPTS into LIBBPF_OPTSAndrii Nakryiko
It's confusing that libbpf-provided helper macro doesn't start with LIBBPF. Also "declare" vs "define" is confusing terminology, I can never remember and always have to look up previous examples. Bypass both issues by renaming DECLARE_LIBBPF_OPTS into a short and clean LIBBPF_OPTS. To avoid breaking existing code, provide: #define DECLARE_LIBBPF_OPTS LIBBPF_OPTS in libbpf_legacy.h. We can decide later if we ever want to remove it or we'll keep it forever because it doesn't add any maintainability burden. Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Dave Marchevsky <davemarchevsky@fb.com> Link: https://lore.kernel.org/bpf/20211103220845.2676888-2-andrii@kernel.org
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