BMC/Intel-BMC/linux.git/tools/lib/bpf/btf.c, branch dev-5.2

libbpf: move logging helpers into libbpf_internal.h

2019-05-16T19:47:47+00:00

libbpf_util.h header was recently exposed as public as a dependency of xsk.h. In addition to memory barriers, it contained logging helpers, which are not supposed to be exposed. This patch moves those into libbpf_internal.h, which is kept as an internal header. Cc: Stanislav Fomichev Cc: Daniel Borkmann Fixes: 7080da890984 ("libbpf: add libbpf_util.h to header install.") Signed-off-by: Andrii Nakryiko Signed-off-by: Alexei Starovoitov

btf: add support for VAR and DATASEC in btf_dedup()

2019-04-16T07:50:20+00:00

This patch adds support for VAR and DATASEC in btf_dedup(). VAR/DATASEC are never deduplicated, but they need to be processed anyway as types they refer to might need to be remapped due to deduplication and compaction. Cc: Daniel Borkmann Cc: Yonghong Song Cc: Alexei Starovoitov Signed-off-by: Andrii Nakryiko Signed-off-by: Daniel Borkmann

Merge git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next

2019-04-12T00:00:05+00:00

Daniel Borkmann says: ==================== pull-request: bpf-next 2019-04-12 The following pull-request contains BPF updates for your *net-next* tree. The main changes are: 1) Improve BPF verifier scalability for large programs through two optimizations: i) remove verifier states that are not useful in pruning, ii) stop walking parentage chain once first LIVE_READ is seen. Combined gives approx 20x speedup. Increase limits for accepting large programs under root, and add various stress tests, from Alexei. 2) Implement global data support in BPF. This enables static global variables for .data, .rodata and .bss sections to be properly handled which allows for more natural program development. This also opens up the possibility to optimize program workflow by compiling ELFs only once and later only rewriting section data before reload, from Daniel and with test cases and libbpf refactoring from Joe. 3) Add config option to generate BTF type info for vmlinux as part of the kernel build process. DWARF debug info is converted via pahole to BTF. Latter relies on libbpf and makes use of BTF deduplication algorithm which results in 100x savings compared to DWARF data. Resulting .BTF section is typically about 2MB in size, from Andrii. 4) Add BPF verifier support for stack access with variable offset from helpers and add various test cases along with it, from Andrey. 5) Extend bpf_skb_adjust_room() growth BPF helper to mark inner MAC header so that L2 encapsulation can be used for tc tunnels, from Alan. 6) Add support for input __sk_buff context in BPF_PROG_TEST_RUN so that users can define a subset of allowed __sk_buff fields that get fed into the test program, from Stanislav. 7) Add bpf fs multi-dimensional array tests for BTF test suite and fix up various UBSAN warnings in bpftool, from Yonghong. 8) Generate a pkg-config file for libbpf, from Luca. 9) Dump program's BTF id in bpftool, from Prashant. 10) libbpf fix to use smaller BPF log buffer size for AF_XDP's XDP program, from Magnus. 11) kallsyms related fixes for the case when symbols are not present in BPF selftests and samples, from Daniel ==================== Signed-off-by: David S. Miller

bpf, libbpf: add support for BTF Var and DataSec

2019-04-10T00:05:47+00:00

This adds libbpf support for BTF Var and DataSec kinds. Main point here is that libbpf needs to do some preparatory work before the whole BTF object can be loaded into the kernel, that is, fixing up of DataSec size taken from the ELF section size and non-static variable offset which needs to be taken from the ELF's string section. Upstream LLVM doesn't fix these up since at time of BTF emission it is too early in the compilation process thus this information isn't available yet, hence loader needs to take care of it. Note, deduplication handling has not been in the scope of this work and needs to be addressed in a future commit. Signed-off-by: Daniel Borkmann Link: https://reviews.llvm.org/D59441 Acked-by: Martin KaFai Lau Signed-off-by: Alexei Starovoitov

libbpf: fix btf_dedup equivalence check handling of different kinds

2019-03-27T15:01:24+00:00

btf_dedup_is_equiv() used to compare btf_type->info fields, before doing kind-specific equivalence check. This comparsion implicitly verified that candidate and canonical types are of the same kind. With enum fwd resolution logic this check couldn't be done generically anymore, as for enums info contains vlen, which differs between enum fwd and fully-defined enum, so this check was subsumed by kind-specific equivalence checks. This change caused btf_dedup_is_equiv() to let through VOID vs other types check to reach switch, which was never meant to be handing VOID kind, as VOID kind is always pre-resolved to itself and is only equivalent to itself, which is checked early in btf_dedup_is_equiv(). This change adds back BTF kind equality check in place of more generic btf_type->info check, still defering further kind-specific checks to a per-kind switch. Fixes: 9768095ba97c ("btf: resolve enum fwds in btf_dedup") Signed-off-by: Andrii Nakryiko Signed-off-by: Alexei Starovoitov

btf: resolve enum fwds in btf_dedup

2019-03-14T20:53:18+00:00

GCC and clang support enum forward declarations as an extension. Such forward-declared enums will be represented as normal BTF_KIND_ENUM types with vlen=0. This patch adds ability to resolve such enums to their corresponding fully defined enums. This helps to avoid duplicated BTF type graphs which only differ by some types referencing forward-declared enum vs full enum. One such example in kernel is enum irqchip_irq_state, defined in include/linux/interrupt.h and forward-declared in include/linux/irq.h. This causes entire struct task_struct and all referenced types to be duplicated in btf_dedup output. This patch eliminates such duplication cases. Signed-off-by: Andrii Nakryiko Signed-off-by: Alexei Starovoitov

btf: fix bug with resolving STRUCT/UNION into corresponding FWD

2019-03-01T00:31:48+00:00

When checking available canonical candidates for struct/union algorithm utilizes btf_dedup_is_equiv to determine if candidate is suitable. This check is not enough when candidate is corresponding FWD for that struct/union, because according to equivalence logic they are equivalent. When it so happens that FWD and STRUCT/UNION end in hashing to the same bucket, it's possible to create remapping loop from FWD to STRUCT and STRUCT to same FWD, which will cause btf_dedup() to loop forever. This patch fixes the issue by additionally checking that type and canonical candidate are strictly equal (utilizing btf_equal_struct). Fixes: d5caef5b5655 ("btf: add BTF types deduplication algorithm") Reported-by: Arnaldo Carvalho de Melo Signed-off-by: Andrii Nakryiko Acked-by: Song Liu Acked-by: Yonghong Song Signed-off-by: Daniel Borkmann

btf: allow to customize dedup hash table size

2019-03-01T00:31:47+00:00

Default size of dedup table (16k) is good enough for most binaries, even typical vmlinux images. But there are cases of binaries with huge amount of BTF types (e.g., allyesconfig variants of kernel), which benefit from having bigger dedup table size to lower amount of unnecessary hash collisions. Tools like pahole, thus, can tune this parameter to reach optimal performance. This change also serves double purpose of allowing tests to force hash collisions to test some corner cases, used in follow up patch. Signed-off-by: Andrii Nakryiko Acked-by: Yonghong Song Signed-off-by: Daniel Borkmann

tools/libbpf: signedness bug in btf_dedup_ref_type()

2019-02-28T23:56:06+00:00

The "ref_type_id" variable needs to be signed for the error handling to work. Fixes: d5caef5b5655 ("btf: add BTF types deduplication algorithm") Signed-off-by: Dan Carpenter Acked-by: Andrii Nakryiko Acked-by: Song Liu Signed-off-by: Daniel Borkmann

tools/libbpf: support bigger BTF data sizes

2019-02-17T02:47:18+00:00

While it's understandable why kernel limits number of BTF types to 65535 and size of string section to 64KB, in libbpf as user-space library it's too restrictive. E.g., pahole converting DWARF to BTF type information for Linux kernel generates more than 3 million BTF types and more than 3MB of strings, before deduplication. So to allow btf__dedup() to do its work, we need to be able to load bigger BTF sections using btf__new(). Singed-off-by: Andrii Nakryiko Signed-off-by: Alexei Starovoitov