- 17 Sep, 2021 3 commits
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Andrii Nakryiko authored
It's relevant and hasn't been doing anything for a long while now. Deprecated it. 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/20210916015836.1248906-4-andrii@kernel.org
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Andrii Nakryiko authored
relaxed_core_relocs option hasn't had any effect for a while now, stop specifying it. Next patch marks it as deprecated. 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/20210916015836.1248906-3-andrii@kernel.org
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Andrii Nakryiko authored
Don't perform another search for sec_def inside libbpf_find_attach_btf_id(), as each recognized bpf_program already has prog->sec_def set. Also remove unnecessary NULL check for prog->sec_name, as it can never be NULL. 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/20210916015836.1248906-2-andrii@kernel.org
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- 15 Sep, 2021 17 commits
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Matteo Croce authored
BPF programs run with migration disabled regardless of preemption, as they are protected by migrate_disable(). Update the uapi documentation accordingly. Signed-off-by: Matteo Croce <mcroce@microsoft.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Yonghong Song <yhs@fb.com> Link: https://lore.kernel.org/bpf/20210914235400.59427-1-mcroce@linux.microsoft.com
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Grant Seltzer authored
This adds comments above five functions in btf.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 Signed-off-by: Grant Seltzer <grantseltzer@gmail.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20210915021951.117186-1-grantseltzer@gmail.com
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Yonghong Song authored
Commit c240ba28 ("selftests/bpf: Add a test with a bpf program with btf_tag attributes") added btf_tag selftest to test BTF_KIND_TAG generation from C source code, and to test kernel validation of generated BTF types. But if an old clang (clang 13 or earlier) is used, the following compiler warning may be seen: progs/tag.c:23:20: warning: unknown attribute 'btf_tag' ignored and the test itself is marked OK. The compiler warning is bad and the test itself shouldn't be marked OK. This patch added the check for btf_tag attribute support. If btf_tag is not supported by the clang, the attribute will not be used in the code and the test will be marked as skipped. For example, with clang 13: ./test_progs -t btf_tag #21 btf_tag:SKIP Summary: 1/0 PASSED, 1 SKIPPED, 0 FAILED The selftests/README.rst is updated to clarify when the btf_tag test may be skipped. Signed-off-by: Yonghong Song <yhs@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20210915061036.2577971-1-yhs@fb.com
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Alexei Starovoitov authored
Yonghong Song says: ==================== LLVM14 added support for a new C attribute ([1]) __attribute__((btf_tag("arbitrary_str"))) This attribute will be emitted to dwarf ([2]) and pahole will convert it to BTF. Or for bpf target, this attribute will be emitted to BTF directly ([3], [4]). The attribute is intended to provide additional information for - struct/union type or struct/union member - static/global variables - static/global function or function parameter. This new attribute can be used to add attributes to kernel codes, e.g., pre- or post- conditions, allow/deny info, or any other info in which only the kernel is interested. Such attributes will be processed by clang frontend and emitted to dwarf, converting to BTF by pahole. Ultimiately the verifier can use these information for verification purpose. The new attribute can also be used for bpf programs, e.g., tagging with __user attributes for function parameters, specifying global function preconditions, etc. Such information may help verifier to detect user program bugs. After this series, pahole dwarf->btf converter will be enhanced to support new llvm tag for btf_tag attribute. With pahole support, we will then try to add a few real use case, e.g., __user/__rcu tagging, allow/deny list, some kernel function precondition, etc, in the kernel. In the rest of the series, Patches 1-2 had kernel support. Patches 3-4 added libbpf support. Patch 5 added bpftool support. Patches 6-10 added various selftests. Patch 11 added documentation for the new kind. [1] https://reviews.llvm.org/D106614 [2] https://reviews.llvm.org/D106621 [3] https://reviews.llvm.org/D106622 [4] https://reviews.llvm.org/D109560 Changelog: v2 -> v3: - put NR_BTF_KINDS and BTF_KIND_MAX into enum as well - check component_idx earlier (check_meta stage) in kernel - add more tests - fix misc nits v1 -> v2: - BTF ELF format changed in llvm ([4] above), so cross-board change to use the new format. - Clarified in commit message that BTF_KIND_TAG is not emitted by bpftool btf dump format c. - Fix various comments from Andrii. ==================== Acked-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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Yonghong Song authored
Add BTF_KIND_TAG documentation in btf.rst. 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/20210914223103.249100-1-yhs@fb.com
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Yonghong Song authored
Add a bpf program with btf_tag attributes. The program is loaded successfully with the kernel. With the command bpftool btf dump file ./tag.o the following dump shows that tags are properly encoded: [8] STRUCT 'key_t' size=12 vlen=3 'a' type_id=2 bits_offset=0 'b' type_id=2 bits_offset=32 'c' type_id=2 bits_offset=64 [9] TAG 'tag1' type_id=8 component_id=-1 [10] TAG 'tag2' type_id=8 component_id=-1 [11] TAG 'tag1' type_id=8 component_id=1 [12] TAG 'tag2' type_id=8 component_id=1 ... [21] FUNC_PROTO '(anon)' ret_type_id=2 vlen=1 'x' type_id=2 [22] FUNC 'foo' type_id=21 linkage=static [23] TAG 'tag1' type_id=22 component_id=0 [24] TAG 'tag2' type_id=22 component_id=0 [25] TAG 'tag1' type_id=22 component_id=-1 [26] TAG 'tag2' type_id=22 component_id=-1 ... [29] VAR 'total' type_id=27, linkage=global [30] TAG 'tag1' type_id=29 component_id=-1 [31] TAG 'tag2' type_id=29 component_id=-1 If an old clang compiler, which does not support btf_tag attribute, is used, these btf_tag attributes will be silently ignored. 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/20210914223058.248949-1-yhs@fb.com
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Yonghong Song authored
Add unit tests for BTF_KIND_TAG deduplication for - struct and struct member - variable - func and func argument 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/20210914223052.248535-1-yhs@fb.com
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Yonghong Song authored
Test good and bad variants of BTF_KIND_TAG encoding. 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/20210914223047.248223-1-yhs@fb.com
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Yonghong Song authored
BTF_KIND_TAG ELF format has a component_idx which might have value -1. test_btf may confuse it with common_type.name as NAME_NTH checkes high 16bit to be 0xffff. Change NAME_NTH high 16bit check to be 0xfffe so it won't confuse with component_idx. 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/20210914223041.248009-1-yhs@fb.com
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Yonghong Song authored
Add btf_write tests with btf__add_tag() function. 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/20210914223036.247560-1-yhs@fb.com
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Yonghong Song authored
Added bpftool support to dump BTF_KIND_TAG information. The new bpftool will be used in later patches to dump btf in the test bpf program object file. Currently, the tags are not emitted with bpftool btf dump file <path> format c and they are silently ignored. The tag information is mostly used in the kernel for verification purpose and the kernel uses its own btf to check. With adding these tags to vmlinux.h, tags will be encoded in program's btf but they will not be used by the kernel, at least for now. So let us delay adding these tags to format C header files until there is a real need. 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/20210914223031.246951-1-yhs@fb.com
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Yonghong Song authored
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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Yonghong Song authored
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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Yonghong Song authored
LLVM14 added support for a new C attribute ([1]) __attribute__((btf_tag("arbitrary_str"))) This attribute will be emitted to dwarf ([2]) and pahole will convert it to BTF. Or for bpf target, this attribute will be emitted to BTF directly ([3], [4]). The attribute is intended to provide additional information for - struct/union type or struct/union member - static/global variables - static/global function or function parameter. For linux kernel, the btf_tag can be applied in various places to specify user pointer, function pre- or post- condition, function allow/deny in certain context, etc. Such information will be encoded in vmlinux BTF and can be used by verifier. The btf_tag can also be applied to bpf programs to help global verifiable functions, e.g., specifying preconditions, etc. This patch added basic parsing and checking support in kernel for new BTF_KIND_TAG kind. [1] https://reviews.llvm.org/D106614 [2] https://reviews.llvm.org/D106621 [3] https://reviews.llvm.org/D106622 [4] https://reviews.llvm.org/D109560Signed-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/20210914223015.245546-1-yhs@fb.com
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Yonghong Song authored
Change BTF_KIND_* macros to enums so they are encoded in dwarf and appear in vmlinux.h. This will make it easier for bpf programs to use these constants without macro definitions. 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/20210914223009.245307-1-yhs@fb.com
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Andrii Nakryiko authored
List all possible test_progs flavors explicitly to avoid accidentally ignoring valid source code files. In this case, test_progs.c was still ignored after recent 809ed84d ("selftests/bpf: Whitelist test_progs.h from .gitignore") fix that added exception only for test_progs.h. Fixes: 74b5a596 ("selftests/bpf: Replace test_progs and test_maps w/ general rule") 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/20210914162228.3995740-1-andrii@kernel.org
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Jie Meng authored
IMUL allows for multiple operands and saving and storing rax/rdx is no longer needed. Signedness of the operands doesn't matter here because the we only keep the lower 32/64 bit of the product for 32/64 bit multiplications. Signed-off-by: Jie Meng <jmeng@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20210913211337.1564014-1-jmeng@fb.com
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- 14 Sep, 2021 6 commits
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Alexei Starovoitov authored
Andrii Nakryiko says: ==================== This small patch set performs internal refactorings around libbpf BPF program ELF section definitions' handling. This is preparatory changes for further changes around making libbpf BPF program section handling more strict but also pluggable and customizable, as part of the libbpf 1.0 effort. See individual patches for details. ==================== Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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Andrii Nakryiko authored
Remove almost all the code that explicitly iterated BPF program section definitions in favor of using find_sec_def(). The only remaining user of section_defs is libbpf_get_type_names that has to iterate all of them to construct its result. Having one internal API entry point for section definitions will simplify further refactorings around libbpf's program section definitions parsing. Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Martin KaFai Lau <kafai@fb.com> Link: https://lore.kernel.org/bpf/20210914014733.2768-5-andrii@kernel.org
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Andrii Nakryiko authored
Remove the need to explicitly pass bpf_sec_def for auto-attachable BPF programs, as it is already recorded at bpf_object__open() time for all recognized type of BPF programs. This further reduces number of explicit calls to find_sec_def(), simplifying further refactorings. No functional changes are done by this patch. Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Martin KaFai Lau <kafai@fb.com> Link: https://lore.kernel.org/bpf/20210914014733.2768-4-andrii@kernel.org
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Andrii Nakryiko authored
Refactor bpf_object__open() sequencing to perform BPF program type detection based on SEC() definitions before we get to relocations collection. This allows to have more information about BPF program by the time we get to, say, struct_ops relocation gathering. This, subsequently, simplifies struct_ops logic and removes the need to perform extra find_sec_def() resolution. With this patch libbpf will require all struct_ops BPF programs to be marked with SEC("struct_ops") or SEC("struct_ops/xxx") annotations. Real-world applications are already doing that through something like selftests's BPF_STRUCT_OPS() macro. This change streamlines libbpf's internal handling of SEC() definitions and is in the sprit of upcoming libbpf-1.0 section strictness changes ([0]). [0] https://github.com/libbpf/libbpf/wiki/Libbpf:-the-road-to-v1.0#stricter-and-more-uniform-bpf-program-section-name-sec-handlingSigned-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Martin KaFai Lau <kafai@fb.com> Link: https://lore.kernel.org/bpf/20210914014733.2768-3-andrii@kernel.org
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Andrii Nakryiko authored
Update struct_ops selftests to always specify "struct_ops" section prefix. Libbpf will require a proper BPF program type set in the next patch, so this prevents tests breaking. Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Martin KaFai Lau <kafai@fb.com> Link: https://lore.kernel.org/bpf/20210914014733.2768-2-andrii@kernel.org
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Rafael David Tinoco authored
Allow kprobe tracepoint events creation through legacy interface, as the kprobe dynamic PMUs support, used by default, was only created in v4.17. Store legacy kprobe name in struct bpf_perf_link, instead of creating a new "subclass" off of bpf_perf_link. This is ok as it's just two new fields, which are also going to be reused for legacy uprobe support in follow up patches. Signed-off-by: Rafael David Tinoco <rafaeldtinoco@gmail.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20210912064844.3181742-1-rafaeldtinoco@gmail.com
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- 13 Sep, 2021 6 commits
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Andrii Nakryiko authored
Turn previously auto-generated libbpf_version.h header into a normal header file. This prevents various tricky Makefile integration issues, simplifies the overall build process, but also allows to further extend it with some more versioning-related APIs in the future. To prevent accidental out-of-sync versions as defined by libbpf.map and libbpf_version.h, Makefile checks their consistency at build time. Simultaneously with this change bump libbpf.map to v0.6. Also undo adding libbpf's output directory into include path for kernel/bpf/preload, bpftool, and resolve_btfids, which is not necessary because libbpf_version.h is just a normal header like any other. Fixes: 0b46b755 ("libbpf: Add LIBBPF_DEPRECATED_SINCE macro for scheduling API deprecations") Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20210913222309.3220849-1-andrii@kernel.org
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Daniel Borkmann authored
The tailcall_3 test program uses bpf_tail_call_static() where the JIT would patch a direct jump. Add a new tailcall_6 test program replicating exactly the same test just ensuring that bpf_tail_call() uses a map index where the verifier cannot make assumptions this time. In other words, this will now cover both on x86-64 JIT, meaning, JIT images with emit_bpf_tail_call_direct() emission as well as JIT images with emit_bpf_tail_call_indirect() emission. # echo 1 > /proc/sys/net/core/bpf_jit_enable # ./test_progs -t tailcalls #136/1 tailcalls/tailcall_1:OK #136/2 tailcalls/tailcall_2:OK #136/3 tailcalls/tailcall_3:OK #136/4 tailcalls/tailcall_4:OK #136/5 tailcalls/tailcall_5:OK #136/6 tailcalls/tailcall_6:OK #136/7 tailcalls/tailcall_bpf2bpf_1:OK #136/8 tailcalls/tailcall_bpf2bpf_2:OK #136/9 tailcalls/tailcall_bpf2bpf_3:OK #136/10 tailcalls/tailcall_bpf2bpf_4:OK #136/11 tailcalls/tailcall_bpf2bpf_5:OK #136 tailcalls:OK Summary: 1/11 PASSED, 0 SKIPPED, 0 FAILED # echo 0 > /proc/sys/net/core/bpf_jit_enable # ./test_progs -t tailcalls #136/1 tailcalls/tailcall_1:OK #136/2 tailcalls/tailcall_2:OK #136/3 tailcalls/tailcall_3:OK #136/4 tailcalls/tailcall_4:OK #136/5 tailcalls/tailcall_5:OK #136/6 tailcalls/tailcall_6:OK [...] For interpreter, the tailcall_1-6 tests are passing as well. The later tailcall_bpf2bpf_* are failing due lack of bpf2bpf + tailcall support in interpreter, so this is expected. Also, manual inspection shows that both loaded programs from tailcall_3 and tailcall_6 test case emit the expected opcodes: * tailcall_3 disasm, emit_bpf_tail_call_direct(): [...] b: push %rax c: push %rbx d: push %r13 f: mov %rdi,%rbx 12: movabs $0xffff8d3f5afb0200,%r13 1c: mov %rbx,%rdi 1f: mov %r13,%rsi 22: xor %edx,%edx _ 24: mov -0x4(%rbp),%eax | limit check 2a: cmp $0x20,%eax | 2d: ja 0x0000000000000046 | 2f: add $0x1,%eax | 32: mov %eax,-0x4(%rbp) |_ 38: nopl 0x0(%rax,%rax,1) 3d: pop %r13 3f: pop %rbx 40: pop %rax 41: jmpq 0xffffffffffffe377 [...] * tailcall_6 disasm, emit_bpf_tail_call_indirect(): [...] 47: movabs $0xffff8d3f59143a00,%rsi 51: mov %edx,%edx 53: cmp %edx,0x24(%rsi) 56: jbe 0x0000000000000093 _ 58: mov -0x4(%rbp),%eax | limit check 5e: cmp $0x20,%eax | 61: ja 0x0000000000000093 | 63: add $0x1,%eax | 66: mov %eax,-0x4(%rbp) |_ 6c: mov 0x110(%rsi,%rdx,8),%rcx 74: test %rcx,%rcx 77: je 0x0000000000000093 79: pop %rax 7a: mov 0x30(%rcx),%rcx 7e: add $0xb,%rcx 82: callq 0x000000000000008e 87: pause 89: lfence 8c: jmp 0x0000000000000087 8e: mov %rcx,(%rsp) 92: retq [...] Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Tested-by: Tiezhu Yang <yangtiezhu@loongson.cn> Acked-by: Yonghong Song <yhs@fb.com> Acked-by: Johan Almbladh <johan.almbladh@anyfinetworks.com> Acked-by: Paul Chaignon <paul@cilium.io> Link: https://lore.kernel.org/bpf/CAM1=_QRyRVCODcXo_Y6qOm1iT163HoiSj8U2pZ8Rj3hzMTT=HQ@mail.gmail.com Link: https://lore.kernel.org/bpf/20210910091900.16119-1-daniel@iogearbox.net
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Alexei Starovoitov authored
Song Liu says: ==================== Changes v6 => v7: 1. Improve/fix intel_pmu_snapshot_branch_stack() logic. (Peter). Changes v5 => v6: 1. Add local_irq_save/restore to intel_pmu_snapshot_branch_stack. (Peter) 2. Remove buf and size check in bpf_get_branch_snapshot, move flags check to later fo the function. (Peter, Andrii) 3. Revise comments for bpf_get_branch_snapshot in bpf.h (Andrii) Changes v4 => v5: 1. Modify perf_snapshot_branch_stack_t to save some memcpy. (Andrii) 2. Minor fixes in selftests. (Andrii) Changes v3 => v4: 1. Do not reshuffle intel_pmu_disable_all(). Use some inline to save LBR entries. (Peter) 2. Move static_call(perf_snapshot_branch_stack) to the helper. (Alexei) 3. Add argument flags to bpf_get_branch_snapshot. (Andrii) 4. Make MAX_BRANCH_SNAPSHOT an enum (Andrii). And rename it as PERF_MAX_BRANCH_SNAPSHOT 5. Make bpf_get_branch_snapshot similar to bpf_read_branch_records. (Andrii) 6. Move the test target function to bpf_testmod. Updated kallsyms_find_next to work properly with modules. (Andrii) Changes v2 => v3: 1. Fix the use of static_call. (Peter) 2. Limit the use to perfmon version >= 2. (Peter) 3. Modify intel_pmu_snapshot_branch_stack() to use intel_pmu_disable_all and intel_pmu_enable_all(). Changes v1 => v2: 1. Rename the helper as bpf_get_branch_snapshot; 2. Fix/simplify the use of static_call; 3. Instead of percpu variables, let intel_pmu_snapshot_branch_stack output branch records to an output argument of type perf_branch_snapshot. Branch stack can be very useful in understanding software events. For example, when a long function, e.g. sys_perf_event_open, returns an errno, it is not obvious why the function failed. Branch stack could provide very helpful information in this type of scenarios. This set adds support to read branch stack with a new BPF helper bpf_get_branch_trace(). Currently, this is only supported in Intel systems. It is also possible to support the same feaure for PowerPC. The hardware that records the branch stace is not stopped automatically on software events. Therefore, it is necessary to stop it in software soon. Otherwise, the hardware buffers/registers will be flushed. One of the key design consideration in this set is to minimize the number of branch record entries between the event triggers and the hardware recorder is stopped. Based on this goal, current design is different from the discussions in original RFC [1]: 1) Static call is used when supported, to save function pointer dereference; 2) intel_pmu_lbr_disable_all is used instead of perf_pmu_disable(), because the latter uses about 10 entries before stopping LBR. With current code, on Intel CPU, LBR is stopped after 7 branch entries after fexit triggers: ID: 0 from bpf_get_branch_snapshot+18 to intel_pmu_snapshot_branch_stack+0 ID: 1 from __brk_limit+477143934 to bpf_get_branch_snapshot+0 ID: 2 from __brk_limit+477192263 to __brk_limit+477143880 # trampoline ID: 3 from __bpf_prog_enter+34 to __brk_limit+477192251 ID: 4 from migrate_disable+60 to __bpf_prog_enter+9 ID: 5 from __bpf_prog_enter+4 to migrate_disable+0 ID: 6 from bpf_testmod_loop_test+20 to __bpf_prog_enter+0 ID: 7 from bpf_testmod_loop_test+20 to bpf_testmod_loop_test+13 ID: 8 from bpf_testmod_loop_test+20 to bpf_testmod_loop_test+13 ... [1] https://lore.kernel.org/bpf/20210818012937.2522409-1-songliubraving@fb.com/ ==================== Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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Song Liu authored
This test uses bpf_get_branch_snapshot from a fexit program. The test uses a target function (bpf_testmod_loop_test) and compares the record against kallsyms. If there isn't enough record matching kallsyms, the test fails. Signed-off-by: Song Liu <songliubraving@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Andrii Nakryiko <andrii@kernel.org> Acked-by: John Fastabend <john.fastabend@gmail.com> Link: https://lore.kernel.org/bpf/20210910183352.3151445-4-songliubraving@fb.com
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Song Liu authored
Introduce bpf_get_branch_snapshot(), which allows tracing pogram to get branch trace from hardware (e.g. Intel LBR). To use the feature, the user need to create perf_event with proper branch_record filtering on each cpu, and then calls bpf_get_branch_snapshot in the bpf function. On Intel CPUs, VLBR event (raw event 0x1b00) can be use for this. Signed-off-by: Song Liu <songliubraving@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: John Fastabend <john.fastabend@gmail.com> Acked-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20210910183352.3151445-3-songliubraving@fb.com
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Song Liu authored
The typical way to access branch record (e.g. Intel LBR) is via hardware perf_event. For CPUs with FREEZE_LBRS_ON_PMI support, PMI could capture reliable LBR. On the other hand, LBR could also be useful in non-PMI scenario. For example, in kretprobe or bpf fexit program, LBR could provide a lot of information on what happened with the function. Add API to use branch record for software use. Note that, when the software event triggers, it is necessary to stop the branch record hardware asap. Therefore, static_call is used to remove some branch instructions in this process. Suggested-by: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Song Liu <songliubraving@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: John Fastabend <john.fastabend@gmail.com> Acked-by: Andrii Nakryiko <andrii@kernel.org> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lore.kernel.org/bpf/20210910183352.3151445-2-songliubraving@fb.com
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- 10 Sep, 2021 8 commits
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Vadim Fedorenko authored
Analogous to the gso_segs selftests introduced in commit d9ff286a ("bpf: allow BPF programs access skb_shared_info->gso_segs field"). Signed-off-by: Vadim Fedorenko <vfedorenko@novek.ru> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Martin KaFai Lau <kafai@fb.com> Link: https://lore.kernel.org/bpf/20210909220409.8804-3-vfedorenko@novek.ru
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Vadim Fedorenko authored
BPF programs may want to know hardware timestamps if NIC supports such timestamping. Expose this data as hwtstamp field of __sk_buff the same way as gso_segs/gso_size. This field could be accessed from the same programs as tstamp field, but it's read-only field. Explicit test to deny access to padding data is added to bpf_skb_is_valid_access. Also update BPF_PROG_TEST_RUN tests of the feature. Signed-off-by: Vadim Fedorenko <vfedorenko@novek.ru> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Martin KaFai Lau <kafai@fb.com> Link: https://lore.kernel.org/bpf/20210909220409.8804-2-vfedorenko@novek.ru
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Daniel Borkmann authored
Magnus Karlsson says: ==================== This patch set facilitates adding new tests as well as describing existing ones in the xsk selftests suite and adds 3 new test suites at the end. The idea is to isolate the run-time that executes the test from the actual implementation of the test. Today, implementing a test amounts to adding test specific if-statements all around the run-time, which is not scalable or amenable for reuse. This patch set instead introduces a test specification that is the only thing that a test fills in. The run-time then gets this specification and acts upon it completely unaware of what test it is executing. This way, we can get rid of all test specific if-statements from the run-time and the implementation of the test can be contained in a single function. This hopefully makes it easier to add tests and for users to understand what the test accomplishes. As a recap of what the run-time does: each test is based on the run-time launching two threads and connecting a veth link between the two threads. Each thread opens an AF_XDP socket on that veth interface and one of them sends traffic that the other one receives and validates. Each thread has its own umem. Note that this behavior is not changed by this patch set. A test specification consists of several items. Most importantly: * Two packet streams. One for Tx thread that specifies what traffic to send and one for the Rx thread that specifies what that thread should receive. If it receives exactly what is specified, the test passes, otherwise it fails. A packet stream can also specify what buffers in the umem that should be used by the Rx and Tx threads. * What kind of AF_XDP sockets it should create and bind to what interfaces * How many times it should repeat the socket creation and destruction * The name of the test The interface for the test spec is the following: void test_spec_init(struct test_spec *test, struct ifobject *ifobj_tx, struct ifobject *ifobj_rx, enum test_mode mode); /* Reset everything but the interface specifications and the mode */ void test_spec_reset(struct test_spec *test); void test_spec_set_name(struct test_spec *test, const char *name); Packet streams have the following interfaces: struct pkt *pkt_stream_get_pkt(struct pkt_stream *pkt_stream, u32 pkt_nb) struct pkt *pkt_stream_get_next_rx_pkt(struct pkt_stream *pkt_stream) struct pkt_stream *pkt_stream_generate(struct xsk_umem_info *umem, u32 nb_pkts, u32 pkt_len); void pkt_stream_delete(struct pkt_stream *pkt_stream); struct pkt_stream *pkt_stream_clone(struct xsk_umem_info *umem, struct pkt_stream *pkt_stream); /* Replaces all packets in the stream*/ void pkt_stream_replace(struct test_spec *test, u32 nb_pkts, u32 pkt_len); /* Replaces every other packet in the stream */ void pkt_stream_replace_half(struct test_spec *test, u32 pkt_len, u32 offset); /* For creating custom made packet streams */ void pkt_stream_generate_custom(struct test_spec *test, struct pkt *pkts, u32 nb_pkts); /* Restores the default packet stream */ void pkt_stream_restore_default(struct test_spec *test); A test can then then in the most basic case described like this (provided the test specification has been created before calling the function): static bool testapp_aligned(struct test_spec *test) { test_spec_set_name(test, "RUN_TO_COMPLETION"); testapp_validate_traffic(test); } Running the same test in unaligned mode would then look like this: static bool testapp_unaligned(struct test_spec *test) { if (!hugepages_present(test->ifobj_tx)) { ksft_test_result_skip("No 2M huge pages present.\n"); return false; } test_spec_set_name(test, "UNALIGNED_MODE"); test->ifobj_tx->umem->unaligned_mode = true; test->ifobj_rx->umem->unaligned_mode = true; /* Let half of the packets straddle a buffer boundrary */ pkt_stream_replace_half(test, PKT_SIZE, XSK_UMEM__DEFAULT_FRAME_SIZE - 32); /* Populate fill ring with addresses in the packet stream */ test->ifobj_rx->pkt_stream->use_addr_for_fill = true; testapp_validate_traffic(test); pkt_stream_restore_default(test); return true; } 3 of the last 4 patches in the set add 3 new test suites, one for unaligned mode, one for testing the rejection of tricky invalid descriptors plus the acceptance of some valid ones in the Tx ring, and one for testing 2K frame sizes (the default is 4K). What is left to do for follow-up patches: * Convert the statistics tests to the new framework. * Implement a way of registering new tests without having the enum test_type. Once this has been done (together with the previous bullet), all the test types can be dropped from the header file. This means that we should be able to add tests by just writing a single function with a new test specification, which is one of the goals. * Introduce functions for manipulating parts of the test or interface spec instead of direct manipulations such as test->ifobj_rx->pkt_stream->use_addr_for_fill = true; which is kind of awkward. * Move the run-time and its interface to its own .c and .h files. Then we can have all the tests in a separate file. * Better error reporting if a test fails. Today it does not state what test fails and might not continue execute the rest of the tests due to this failure. Failures are not propagated upwards through the functions so a failed test will also be a passed test, which messes up the stats counting. This needs to be changed. * Add option to run specific test instead of all of them * Introduce pacing of sent packets so that they are never dropped by the receiver even if it is stalled for some reason. If you run the current tests on a heavily loaded system, they might fail in SKB mode due to packets being dropped by the driver on Tx. Though I have never seen it, it might happen. v1 -> v2: * Fixed a number of spelling errors [Maciej] * Fixed use after free bug in pkt_stream_replace() [Maciej] * pkt_stream_set -> pkt_stream_generate_custom [Maciej] * Fixed formatting problem in testapp_invalid_desc() [Maciej] ==================== Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
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Magnus Karlsson authored
Add tests for 2K frame size. Both a standard send and receive test and one testing for invalid descriptors when the frame size is 2K. Signed-off-by: Magnus Karlsson <magnus.karlsson@intel.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Maciej Fijalkowski <maciej.fijalkowski@intel.com> Link: https://lore.kernel.org/bpf/20210907071928.9750-21-magnus.karlsson@gmail.com
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Magnus Karlsson authored
Add tests for invalid xsk descriptors in the Tx ring. A number of handcrafted nasty invalid descriptors are created and submitted to the tx ring to check that they are validated correctly. Corner case valid ones are also sent. The tests are run for both aligned and unaligned mode. pkt_stream_set() is introduced to be able to create a hand-crafted packet stream where every single packet is specified in detail. Signed-off-by: Magnus Karlsson <magnus.karlsson@intel.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Maciej Fijalkowski <maciej.fijalkowski@intel.com> Link: https://lore.kernel.org/bpf/20210907071928.9750-20-magnus.karlsson@gmail.com
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Magnus Karlsson authored
Eliminate a test specific if-statement for the RX_FILL_EMTPY stats test that is present in the test runner. We can do this as we now have the use_addr_for_fill option. Just create and empty Rx packet stream and indicated that the test runner should use the addresses in that to populate the fill ring. As there are no packets in the stream, the fill ring will be empty and we will get the error stats that we want to test. Signed-off-by: Magnus Karlsson <magnus.karlsson@intel.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Maciej Fijalkowski <maciej.fijalkowski@intel.com> Link: https://lore.kernel.org/bpf/20210907071928.9750-19-magnus.karlsson@gmail.com
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Magnus Karlsson authored
Add a test for unaligned mode in which packet buffers can be placed anywhere within the umem. Some packets are made to straddle page boundaries in order to check for correctness. On the Tx side, buffers are now allocated according to the addresses found in the packet stream. Thus, the placement of buffers can be controlled with the boolean use_addr_for_fill in the packet stream. One new pkt_stream interface is introduced: pkt_stream_replace_half() that replaces every other packet in the default packet stream with the specified new packet. The constant DEFAULT_OFFSET is also introduced. It specifies at what offset from the start of a chunk a Tx packet is placed by the sending thread. This is just to be able to test that it is possible to send packets at an offset not equal to zero. Signed-off-by: Magnus Karlsson <magnus.karlsson@intel.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Maciej Fijalkowski <maciej.fijalkowski@intel.com> Link: https://lore.kernel.org/bpf/20210907071928.9750-18-magnus.karlsson@gmail.com
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Magnus Karlsson authored
Introduce the concept of a default packet stream that is the set of packets sent by most tests. Then add the ability to replace it for a test that would like to send or receive something else through the use of the function pkt_stream_replace() and then restored with pkt_stream_restore_default(). These are then used to convert the STAT_TEST_TX_INVALID to use these new APIs. Signed-off-by: Magnus Karlsson <magnus.karlsson@intel.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Maciej Fijalkowski <maciej.fijalkowski@intel.com> Link: https://lore.kernel.org/bpf/20210907071928.9750-17-magnus.karlsson@gmail.com
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