kernel.git/tools/bpf/bpftool/main.h, branch linux-6.7.y

bpftool: Support bpffs mountpoint as pin path for prog loadall

2023-05-17T13:58:18Z

Currently, when using prog loadall and the pin path is a bpffs mountpoint, bpffs will be repeatedly mounted to the parent directory of the bpffs mountpoint path. For example, a `bpftool prog loadall test.o /sys/fs/bpf` will trigger this. Signed-off-by: Pengcheng Yang Signed-off-by: Daniel Borkmann Reviewed-by: Quentin Monnet Link: https://lore.kernel.org/bpf/1683342439-3677-1-git-send-email-yangpc@wangsu.com

tools: bpftool: print netfilter link info

2023-04-21T18:34:49Z

Dump protocol family, hook and priority value: $ bpftool link 2: netfilter prog 14 ip input prio -128 pids install(3264) 5: netfilter prog 14 ip6 forward prio 21 pids a.out(3387) 9: netfilter prog 14 ip prerouting prio 123 pids a.out(5700) 10: netfilter prog 14 ip input prio 21 pids test2(5701) v2: Quentin Monnet suggested to also add 'bpftool net' support: $ bpftool net xdp: tc: flow_dissector: netfilter: ip prerouting prio 21 prog_id 14 ip input prio -128 prog_id 14 ip input prio 21 prog_id 14 ip forward prio 21 prog_id 14 ip output prio 21 prog_id 14 ip postrouting prio 21 prog_id 14 'bpftool net' only dumps netfilter link type, links are sorted by protocol family, hook and priority. v5: fix bpf ci failure: libbpf needs small update to prog_type_name[] and probe_prog_load helper. v4: don't fail with -EOPNOTSUPP in libbpf probe_prog_load, update prog_type_name[] with "netfilter" entry (bpf ci) v3: fix bpf.h copy, 'reserved' member was removed (Alexei) use p_err, not fprintf (Quentin) Suggested-by: Quentin Monnet Link: https://lore.kernel.org/bpf/eeeaac99-9053-90c2-aa33-cc1ecb1ae9ca@isovalent.com/ Reviewed-by: Quentin Monnet Signed-off-by: Florian Westphal Link: https://lore.kernel.org/r/20230421170300.24115-6-fw@strlen.de Signed-off-by: Alexei Starovoitov

bpftool: Register struct_ops with a link.

2023-04-21T18:10:10Z

You can include an optional path after specifying the object name for the 'struct_ops register' subcommand. Since the commit 226bc6ae6405 ("Merge branch 'Transit between BPF TCP congestion controls.'") has been accepted, it is now possible to create a link for a struct_ops. This can be done by defining a struct_ops in SEC(".struct_ops.link") to make libbpf returns a real link. If we don't pin the links before leaving bpftool, they will disappear. To instruct bpftool to pin the links in a directory with the names of the maps, we need to provide the path of that directory. Signed-off-by: Kui-Feng Lee Reviewed-by: Quentin Monnet Link: https://lore.kernel.org/r/20230420002822.345222-1-kuifeng@meta.com Signed-off-by: Alexei Starovoitov

bpftool: Support printing opcodes and source file references in CFG

2023-04-06T04:27:27Z

Add support for displaying opcodes or/and file references (filepath, line and column numbers) when dumping the control flow graphs of loaded BPF programs with bpftool. The filepaths in the records are absolute. To avoid blocks on the graph to get too wide, we truncate them when they get too long (but we always keep the entire file name). In the unlikely case where the resulting file name is ambiguous, it remains possible to get the full path with a regular dump (no CFG). Signed-off-by: Quentin Monnet Link: https://lore.kernel.org/r/20230405132120.59886-7-quentin@isovalent.com Signed-off-by: Alexei Starovoitov

bpftool: Support inline annotations when dumping the CFG of a program

2023-04-06T04:27:27Z

We support dumping the control flow graph of loaded programs to the DOT format with bpftool, but so far this feature wouldn't display the source code lines available through BTF along with the eBPF bytecode. Let's add support for these annotations, to make it easier to read the graph. In prog.c, we move the call to dump_xlated_cfg() in order to pass and use the full struct dump_data, instead of creating a minimal one in draw_bb_node(). We pass the pointer to this struct down to dump_xlated_for_graph() in xlated_dumper.c, where most of the logics is added. We deal with BTF mostly like we do for plain or JSON output, except that we cannot use a "nr_skip" value to skip a given number of linfo records (we don't process the BPF instructions linearly, and apart from the root of the graph we don't know how many records we should skip, so we just store the last linfo and make sure the new one we find is different before printing it). When printing the source instructions to the label of a DOT graph node, there are a few subtleties to address. We want some special newline markers, and there are some characters that we must escape. To deal with them, we introduce a new dedicated function btf_dump_linfo_dotlabel() in btf_dumper.c. We'll reuse this function in a later commit to format the filepath, line, and column references as well. Signed-off-by: Quentin Monnet Link: https://lore.kernel.org/r/20230405132120.59886-4-quentin@isovalent.com Signed-off-by: Alexei Starovoitov

bpftool: Use bpf_{btf,link,map,prog}_get_info_by_fd()

2023-02-16T23:32:45Z

Use the new type-safe wrappers around bpf_obj_get_info_by_fd(). Split the bpf_obj_get_info_by_fd() call in build_btf_type_table() in two, since knowing the type helps with the Memory Sanitizer. Improve map_parse_fd_and_info() type safety by using struct bpf_map_info * instead of void * for info. Signed-off-by: Ilya Leoshkevich Signed-off-by: Andrii Nakryiko Reviewed-by: Quentin Monnet Link: https://lore.kernel.org/bpf/20230214231221.249277-4-iii@linux.ibm.com

bpftool: remove support of --legacy option for bpftool

2022-11-21T00:17:46Z

Following: commit bd054102a8c7 ("libbpf: enforce strict libbpf 1.0 behaviors") commit 93b8952d223a ("libbpf: deprecate legacy BPF map definitions") The --legacy option is no longer relevant as libbpf no longer supports it. libbpf_set_strict_mode() is a no-op operation. Signed-off-by: Sahid Orentino Ferdjaoui Acked-by: Yonghong Song Reviewed-by: Quentin Monnet Link: https://lore.kernel.org/r/20221120112515.38165-2-sahid.ferdjaoui@industrialdiscipline.com Signed-off-by: Alexei Starovoitov

libbpf: Hashmap interface update to allow both long and void* keys/values

2022-11-10T04:45:14Z

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 Signed-off-by: Andrii Nakryiko Link: https://lore.kernel.org/bpf/20221109142611.879983-2-eddyz87@gmail.com

bpftool: Support setting alternative arch for JIT disasm with LLVM

2022-10-25T17:11:56Z

For offloaded BPF programs, instead of failing to create the LLVM disassembler without even looking for a triple at all, do run the function that attempts to retrieve a valid architecture name for the device. It will still fail for the LLVM disassembler, because currently we have no valid triple to return (NFP disassembly is not supported by LLVM). But failing in that function is more logical than to assume in jit_disasm.c that passing an "arch" name is simply not supported. Suggested-by: Song Liu Signed-off-by: Quentin Monnet Link: https://lore.kernel.org/r/20221025150329.97371-8-quentin@isovalent.com Signed-off-by: Alexei Starovoitov

bpftool: Add LLVM as default library for disassembling JIT-ed programs

2022-10-25T17:11:56Z

To disassemble instructions for JIT-ed programs, bpftool has relied on the libbfd library. This has been problematic in the past: libbfd's interface is not meant to be stable and has changed several times. For building bpftool, we have to detect how the libbfd version on the system behaves, which is why we have to handle features disassembler-four-args and disassembler-init-styled in the Makefile. When it comes to shipping bpftool, this has also caused issues with several distribution maintainers unwilling to support the feature (see for example Debian's page for binutils-dev, which ships libbfd: "Note that building Debian packages which depend on the shared libbfd is Not Allowed." [0]). For these reasons, we add support for LLVM as an alternative to libbfd for disassembling instructions of JIT-ed programs. Thanks to the preparation work in the previous commits, it's easy to add the library by passing the relevant compilation options in the Makefile, and by adding the functions for setting up the LLVM disassembler in file jit_disasm.c. The LLVM disassembler requires the LLVM development package (usually llvm-dev or llvm-devel). The expectation is that the interface for this disassembler will be more stable. There is a note in LLVM's Developer Policy [1] stating that the stability for the C API is "best effort" and not guaranteed, but at least there is some effort to keep compatibility when possible (which hasn't really been the case for libbfd so far). Furthermore, the Debian page for the related LLVM package does not caution against linking to the lib, as binutils-dev page does. Naturally, the display of disassembled instructions comes with a few minor differences. Here is a sample output with libbfd (already supported before this patch): # bpftool prog dump jited id 56 bpf_prog_6deef7357e7b4530: 0: nopl 0x0(%rax,%rax,1) 5: xchg %ax,%ax 7: push %rbp 8: mov %rsp,%rbp b: push %rbx c: push %r13 e: push %r14 10: mov %rdi,%rbx 13: movzwq 0xb4(%rbx),%r13 1b: xor %r14d,%r14d 1e: or $0x2,%r14d 22: mov $0x1,%eax 27: cmp $0x2,%r14 2b: jne 0x000000000000002f 2d: xor %eax,%eax 2f: pop %r14 31: pop %r13 33: pop %rbx 34: leave 35: ret LLVM supports several variants that we could set when initialising the disassembler, for example with: LLVMSetDisasmOptions(*ctx, LLVMDisassembler_Option_AsmPrinterVariant); but the default printer is used for now. Here is the output with LLVM: # bpftool prog dump jited id 56 bpf_prog_6deef7357e7b4530: 0: nopl (%rax,%rax) 5: nop 7: pushq %rbp 8: movq %rsp, %rbp b: pushq %rbx c: pushq %r13 e: pushq %r14 10: movq %rdi, %rbx 13: movzwq 180(%rbx), %r13 1b: xorl %r14d, %r14d 1e: orl $2, %r14d 22: movl $1, %eax 27: cmpq $2, %r14 2b: jne 0x2f 2d: xorl %eax, %eax 2f: popq %r14 31: popq %r13 33: popq %rbx 34: leave 35: retq The LLVM disassembler comes as the default choice, with libbfd as a fall-back. Of course, we could replace libbfd entirely and avoid supporting two different libraries. One reason for keeping libbfd is that, right now, it works well, we have all we need in terms of features detection in the Makefile, so it provides a fallback for disassembling JIT-ed programs if libbfd is installed but LLVM is not. The other motivation is that libbfd supports nfp instruction for Netronome's SmartNICs and can be used to disassemble offloaded programs, something that LLVM cannot do. If libbfd's interface breaks again in the future, we might reconsider keeping support for it. [0] https://packages.debian.org/buster/binutils-dev [1] https://llvm.org/docs/DeveloperPolicy.html#c-api-changes Signed-off-by: Quentin Monnet Tested-by: Niklas Söderlund Acked-by: Yonghong Song Link: https://lore.kernel.org/r/20221025150329.97371-7-quentin@isovalent.com Signed-off-by: Alexei Starovoitov