kernel.git/tools/bpf/resolve_btfids, branch linux-5.16.y

tools/resolve_btfids: Do not print any commands when building silently

2022-02-08T17:35:18Z

commit 7f3bdbc3f13146eb9d07de81ea71f551587a384b upstream. When building with 'make -s', there is some output from resolve_btfids: $ make -sj"$(nproc)" oldconfig prepare MKDIR .../tools/bpf/resolve_btfids/libbpf/ MKDIR .../tools/bpf/resolve_btfids//libsubcmd LINK resolve_btfids Silent mode means that no information should be emitted about what is currently being done. Use the $(silent) variable from Makefile.include to avoid defining the msg macro so that there is no information printed. Fixes: fbbb68de80a4 ("bpf: Add resolve_btfids tool to resolve BTF IDs in ELF object") Signed-off-by: Nathan Chancellor Signed-off-by: Daniel Borkmann Link: https://lore.kernel.org/bpf/20220201212503.731732-1-nathan@kernel.org Signed-off-by: Greg Kroah-Hartman

tools/resolve_btf_ids: Close ELF file on error

2022-01-27T11:01:34Z

[ Upstream commit 1144ab9bdf3430e1b5b3f22741e5283841951add ] Fix one case where we don't do explicit clean up. Fixes: fbbb68de80a4 ("bpf: Add resolve_btfids tool to resolve BTF IDs in ELF object") Signed-off-by: Andrii Nakryiko Signed-off-by: Daniel Borkmann Link: https://lore.kernel.org/bpf/20211124002325.1737739-2-andrii@kernel.org Signed-off-by: Sasha Levin

tools/resolve_btfids: Skip unresolved symbol warning for empty BTF sets

2021-12-02T21:39:46Z

resolve_btfids prints a warning when it finds an unresolved symbol, (id == 0) in id_patch. This can be the case for BTF sets that are empty (due to disabled config options), hence printing warnings for certain builds, most recently seen in [0]. The reason behind this is because id->cnt aliases id->id in btf_id struct, leading to empty set showing up as ID 0 when we get to id_patch, which triggers the warning. Since sets are an exception here, accomodate by reusing hole in btf_id for bool is_set member, setting it to true for BTF set when setting id->cnt, and use that to skip extraneous warning. [0]: https://lore.kernel.org/all/1b99ae14-abb4-d18f-cc6a-d7e523b25542@gmail.com Before: ; ./tools/bpf/resolve_btfids/resolve_btfids -v -b vmlinux net/ipv4/tcp_cubic.ko adding symbol tcp_cubic_kfunc_ids WARN: resolve_btfids: unresolved symbol tcp_cubic_kfunc_ids patching addr 0: ID 0 [tcp_cubic_kfunc_ids] sorting addr 4: cnt 0 [tcp_cubic_kfunc_ids] update ok for net/ipv4/tcp_cubic.ko After: ; ./tools/bpf/resolve_btfids/resolve_btfids -v -b vmlinux net/ipv4/tcp_cubic.ko adding symbol tcp_cubic_kfunc_ids patching addr 0: ID 0 [tcp_cubic_kfunc_ids] sorting addr 4: cnt 0 [tcp_cubic_kfunc_ids] update ok for net/ipv4/tcp_cubic.ko Fixes: 0e32dfc80bae ("bpf: Enable TCP congestion control kfunc from modules") Reported-by: Pavel Skripkin Signed-off-by: Kumar Kartikeya Dwivedi Signed-off-by: Andrii Nakryiko Acked-by: Song Liu Link: https://lore.kernel.org/bpf/20211122144742.477787-4-memxor@gmail.com

tools/resolve_btfids: Switch to new btf__type_cnt API

2021-10-22T23:09:14Z

Replace the call to btf__get_nr_types with new API btf__type_cnt. The old API will be deprecated in libbpf v0.7+. No functionality change. Signed-off-by: Hengqi Chen Signed-off-by: Andrii Nakryiko Link: https://lore.kernel.org/bpf/20211022130623.1548429-4-hengqi.chen@gmail.com

tools/resolve_btfids: Install libbpf headers when building

2021-10-08T18:54:11Z

API headers from libbpf should not be accessed directly from the library's source directory. Instead, they should be exported with "make install_headers". Let's make sure that resolve_btfids installs the headers properly when building. When descending from a parent Makefile, the specific output directories for building the library and exporting the headers are configurable with LIBBPF_OUT and LIBBPF_DESTDIR, respectively. This is in addition to OUTPUT, on top of which those variables are constructed by default. Also adjust the Makefile for the BPF selftests in order to point to the (target) libbpf shared with other tools, instead of building a version specific to resolve_btfids. Remove libbpf's order-only dependencies on the include directories (they are created by libbpf and don't need to exist beforehand). Signed-off-by: Quentin Monnet Signed-off-by: Andrii Nakryiko Acked-by: Andrii Nakryiko Link: https://lore.kernel.org/bpf/20211007194438.34443-5-quentin@isovalent.com

tools: Allow specifying base BTF file in resolve_btfids

2021-10-06T00:07:41Z

This commit allows specifying the base BTF for resolving btf id lists/sets during link time in the resolve_btfids tool. The base BTF is set to NULL if no path is passed. This allows resolving BTF ids for module kernel objects. Also, drop the --no-fail option, as it is only used in case .BTF_ids section is not present, instead make no-fail the default mode. The long option name is same as that of pahole. Signed-off-by: Kumar Kartikeya Dwivedi Signed-off-by: Alexei Starovoitov Acked-by: Andrii Nakryiko Link: https://lore.kernel.org/bpf/20211002011757.311265-5-memxor@gmail.com

libbpf: Make libbpf_version.h non-auto-generated

2021-09-13T22:36:47Z

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: 0b46b7550560 ("libbpf: Add LIBBPF_DEPRECATED_SINCE macro for scheduling API deprecations") Signed-off-by: Andrii Nakryiko Signed-off-by: Alexei Starovoitov Link: https://lore.kernel.org/bpf/20210913222309.3220849-1-andrii@kernel.org

libbpf: Add LIBBPF_DEPRECATED_SINCE macro for scheduling API deprecations

2021-09-09T21:28:05Z

Introduce a macro LIBBPF_DEPRECATED_SINCE(major, minor, message) to prepare the deprecation of two API functions. This macro marks functions as deprecated when libbpf's version reaches the values passed as an argument. As part of this change libbpf_version.h header is added with recorded major (LIBBPF_MAJOR_VERSION) and minor (LIBBPF_MINOR_VERSION) libbpf version macros. They are now part of libbpf public API and can be relied upon by user code. libbpf_version.h is installed system-wide along other libbpf public headers. Due to this new build-time auto-generated header, in-kernel applications relying on libbpf (resolve_btfids, bpftool, bpf_preload) are updated to include libbpf's output directory as part of a list of include search paths. Better fix would be to use libbpf's make_install target to install public API headers, but that clean up is left out as a future improvement. The build changes were tested by building kernel (with KBUILD_OUTPUT and O= specified explicitly), bpftool, libbpf, selftests/bpf, and resolve_btfids builds. No problems were detected. Note that because of the constraints of the C preprocessor we have to write a few lines of macro magic for each version used to prepare deprecation (0.6 for now). Also, use LIBBPF_DEPRECATED_SINCE() to schedule deprecation of btf__get_from_id() and btf__load(), which are replaced by btf__load_from_kernel_by_id() and btf__load_into_kernel(), respectively, starting from future libbpf v0.6. This is part of libbpf 1.0 effort ([0]). [0] Closes: https://github.com/libbpf/libbpf/issues/278 Co-developed-by: Quentin Monnet Co-developed-by: Andrii Nakryiko Signed-off-by: Quentin Monnet Signed-off-by: Andrii Nakryiko Signed-off-by: Daniel Borkmann Link: https://lore.kernel.org/bpf/20210908213226.1871016-1-andrii@kernel.org

tools/resolve_btfids: Emit warnings and patch zero id for missing symbols

2021-07-29T21:37:23Z

Kernel functions referenced by .BTF_ids may be changed from global to static and get inlined or get renamed/removed, and thus disappears from BTF. This causes kernel build failure when resolve_btfids do id patch for symbols in .BTF_ids in vmlinux. Update resolve_btfids to emit warning messages and patch zero id for missing symbols instead of aborting kernel build process. Suggested-by: Andrii Nakryiko Signed-off-by: Hengqi Chen Signed-off-by: Andrii Nakryiko Acked-by: Yonghong Song Link: https://lore.kernel.org/bpf/20210727132532.2473636-2-hengqi.chen@gmail.com

bpf: Fix libelf endian handling in resolv_btfids

2021-06-18T15:01:00Z

The vmlinux ".BTF_ids" ELF section is declared in btf_ids.h to hold a list of zero-filled BTF IDs, which is then patched at link-time with correct values by resolv_btfids. The section is flagged as "allocable" to preclude compression, but notably the section contents (BTF IDs) are untyped. When patching the BTF IDs, resolve_btfids writes in host-native endianness and relies on libelf for any required translation on reading and updating vmlinux. However, since the type of the .BTF_ids section content defaults to ELF_T_BYTE (i.e. unsigned char), no translation occurs. This results in incorrect patched values when cross-compiling to non-native endianness, and can manifest as kernel Oops and test failures which are difficult to troubleshoot [1]. Explicitly set the type of patched data to ELF_T_WORD, the architecture- neutral ELF type corresponding to the u32 BTF IDs. This enables libelf to transparently perform any needed endian conversions. Fixes: fbbb68de80a4 ("bpf: Add resolve_btfids tool to resolve BTF IDs in ELF object") Signed-off-by: Tony Ambardar Signed-off-by: Daniel Borkmann Acked-by: Jiri Olsa Cc: Frank Eigler Cc: Mark Wielaard Cc: Jiri Olsa Cc: Yonghong Song Link: https://lore.kernel.org/bpf/CAPGftE_eY-Zdi3wBcgDfkz_iOr1KF10n=9mJHm1_a_PykcsoeA@mail.gmail.com [1] Link: https://lore.kernel.org/bpf/20210618061404.818569-1-Tony.Ambardar@gmail.com