Changes in Makefile

c73a24436698ade1b6a0742e8bcfa04c9ef8fad9 - bpftool: Allow explicitly skip llvm, libbfd and libcrypto dependencies

Fri, 13 Mar 2026 01:03:27 +0100

bpftool: Allow explicitly skip llvm, libbfd and libcrypto dependenciesIntroduce SKIP_LLVM, SKIP_LIBBFD, and SKIP_CRYPTO build flags that letusers build bpftool without these optional dependencies.SKIP_LLVM=1 skips LLVM even when detected. SKIP_LIBBFD=1 prevents thelibbfd JIT disassembly fallback when LLVM is absent. Together, theyproduce a bpftool with no disassembly support.SKIP_CRYPTO=1 excludes sign.c and removes the -lcrypto link dependency.Inline stubs in main.h return errors with a clear message if signingfunctions are called at runtime.Use BPFTOOL_WITHOUT_CRYPTO (not HAVE_LIBCRYPTO_SUPPORT) as the Cdefine, following the BPFTOOL_WITHOUT_SKELETONS naming convention forbpftool-internal build config, leaving HAVE_LIBCRYPTO_SUPPORT free forproper feature detection in the future.All three flags are propagated through the selftests Makefile to bpftoolsub-builds.Signed-off-by: Mykyta Yatsenko Signed-off-by: Andrii Nakryiko Link: https://lore.kernel.org/bpf/20260312-b4-bpftool_build-v2-1-4c9d57133644@meta.com List of files: /linux/tools/bpf/bpftool/Makefile

08a7491843224f8b96518fbe70d9e48163046054 - bpftool: Fix dependencies for static build

Wed, 28 Jan 2026 22:12:55 +0100

bpftool: Fix dependencies for static buildWhen building selftests/bpf with EXTRA_LDFLAGS=-static the follwoingerror happens: LINK /ws/linux/tools/testing/selftests/bpf/tools/build/bpftool/bootstrap/bpftool/usr/bin/x86_64-linux-gnu-ld.bfd: /usr/lib/gcc/x86_64-linux-gnu/15/../../../x86_64-linux-gnu/libcrypto.a(libcrypto-lib-dso_dlfcn.o): in function `dlfcn_globallookup': [...]/usr/bin/x86_64-linux-gnu-ld.bfd: /usr/lib/gcc/x86_64-linux-gnu/15/../../../x86_64-linux-gnu/libcrypto.a(libcrypto-lib-c_zlib.o): in function `zlib_oneshot_expand_block':(.text+0xc64): undefined reference to `uncompress'/usr/bin/x86_64-linux-gnu-ld.bfd: /usr/lib/gcc/x86_64-linux-gnu/15/../../../x86_64-linux-gnu/libcrypto.a(libcrypto-lib-c_zlib.o): in function `zlib_oneshot_compress_block':(.text+0xce4): undefined reference to `compress'collect2: error: ld returned 1 exit statusmake[1]: *** [Makefile:252: /ws/linux/tools/testing/selftests/bpf/tools/build/bpftool/bootstrap/bpftool] Error 1make: *** [Makefile:327: /ws/linux/tools/testing/selftests/bpf/tools/sbin/bpftool] Error 2make: *** Waiting for unfinished jobs....This is caused by wrong order of dependencies in the Makefile. Fix it.Signed-off-by: Ihor Solodrai Signed-off-by: Andrii Nakryiko Link: https://lore.kernel.org/bpf/20260128211255.376933-1-ihor.solodrai@linux.dev List of files: /linux/tools/bpf/bpftool/Makefile

639f58a0f4808e78ff6c764747ee125c0e2f093c - bpftool: Fix build warnings due to MS extensions

Mon, 08 Dec 2025 14:07:48 +0100

bpftool: Fix build warnings due to MS extensionsThe kernel is now built with -fms-extensions. Anonymous structs orunions permitted by these extensions have been used in several places,and can end up in the generated vmlinux.h file, for example: struct ns_tree { [...] }; [...] struct ns_common { [...] union { struct ns_tree; struct callback_head ns_rcu; }; };Trying to include this header for compiling a tool may result in buildwarnings, if the compiler does not expect these extensions. This is thecase, for example, with bpftool: In file included from skeleton/pid_iter.bpf.c:3: .../tools/testing/selftests/bpf/tools/build/bpftool/vmlinux.h:64057:3: warning: declaration does not declare anything [-Wmissing-declarations] 64057 | struct ns_tree; | ^~~~~~~~~~~~~~Fix these build warnings in bpftool by turning on Microsoft extensionswhen compiling the two BPF programs that rely on vmlinux.h.Reported-by: Alexei Starovoitov Closes: https://lore.kernel.org/bpf/CAADnVQK9ZkPC7+R5VXKHVdtj8tumpMXm7BTp0u9CoiFLz_aPTg@mail.gmail.com/Signed-off-by: Quentin Monnet Link: https://lore.kernel.org/r/20251208130748.68371-1-qmo@kernel.orgSigned-off-by: Alexei Starovoitov List of files: /linux/tools/bpf/bpftool/Makefile

40863f4d6ef2c34bb00dd1070dfaf9d5f27a497e - bpftool: Add support for signing BPF programs

Sun, 21 Sep 2025 18:01:19 +0200

bpftool: Add support for signing BPF programsTwo modes of operation being added:Add two modes of operation:* For prog load, allow signing a program immediately before loading. This is essential for command-line testing and administration. bpftool prog load -S -k -i fentry_test.bpf.o* For gen skeleton, embed a pre-generated signature into the C skeleton file. This supports the use of signed programs in compiled applications. bpftool gen skeleton -S -k -i fentry_test.bpf.oGeneration of the loader program and its metadata map is implemented inlibbpf (bpf_obj__gen_loader). bpftool generates a skeleton that loadsthe program and automates the required steps: freezing the map, creatingan exclusive map, loading, and running. Users can use standard libbpfAPIs directly or integrate loader program generation into their owntoolchains.Signed-off-by: KP Singh Acked-by: Quentin Monnet Link: https://lore.kernel.org/r/20250921160120.9711-5-kpsingh@kernel.orgSigned-off-by: Alexei Starovoitov List of files: /linux/tools/bpf/bpftool/Makefile

fa593d0f969dcfa41d390822fdf1a0ab48cd882c - Merge tag 'bpf-next-6.15' of git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next

Sun, 30 Mar 2025 21:43:03 +0200

Merge tag 'bpf-next-6.15' of git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-nextPull bpf updates from Alexei Starovoitov: "For this merge window we're splitting BPF pull request into three for higher visibility: main changes, res_spin_lock, try_alloc_pages. These are the main BPF changes: - Add DFA-based live registers analysis to improve verification of programs with loops (Eduard Zingerman) - Introduce load_acquire and store_release BPF instructions and add x86, arm64 JIT support (Peilin Ye) - Fix loop detection logic in the verifier (Eduard Zingerman) - Drop unnecesary lock in bpf_map_inc_not_zero() (Eric Dumazet) - Add kfunc for populating cpumask bits (Emil Tsalapatis) - Convert various shell based tests to selftests/bpf/test_progs format (Bastien Curutchet) - Allow passing referenced kptrs into struct_ops callbacks (Amery Hung) - Add a flag to LSM bpf hook to facilitate bpf program signing (Blaise Boscaccy) - Track arena arguments in kfuncs (Ihor Solodrai) - Add copy_remote_vm_str() helper for reading strings from remote VM and bpf_copy_from_user_task_str() kfunc (Jordan Rome) - Add support for timed may_goto instruction (Kumar Kartikeya Dwivedi) - Allow bpf_get_netns_cookie() int cgroup_skb programs (Mahe Tardy) - Reduce bpf_cgrp_storage_busy false positives when accessing cgroup local storage (Martin KaFai Lau) - Introduce bpf_dynptr_copy() kfunc (Mykyta Yatsenko) - Allow retrieving BTF data with BTF token (Mykyta Yatsenko) - Add BPF kfuncs to set and get xattrs with 'security.bpf.' prefix (Song Liu) - Reject attaching programs to noreturn functions (Yafang Shao) - Introduce pre-order traversal of cgroup bpf programs (Yonghong Song)"* tag 'bpf-next-6.15' of git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next: (186 commits) selftests/bpf: Add selftests for load-acquire/store-release when register number is invalid bpf: Fix out-of-bounds read in check_atomic_load/store() libbpf: Add namespace for errstr making it libbpf_errstr bpf: Add struct_ops context information to struct bpf_prog_aux selftests/bpf: Sanitize pointer prior fclose() selftests/bpf: Migrate test_xdp_vlan.sh into test_progs selftests/bpf: test_xdp_vlan: Rename BPF sections bpf: clarify a misleading verifier error message selftests/bpf: Add selftest for attaching fexit to __noreturn functions bpf: Reject attaching fexit/fmod_ret to __noreturn functions bpf: Only fails the busy counter check in bpf_cgrp_storage_get if it creates storage bpf: Make perf_event_read_output accessible in all program types. bpftool: Using the right format specifiers bpftool: Add -Wformat-signedness flag to detect format errors selftests/bpf: Test freplace from user namespace libbpf: Pass BPF token from find_prog_btf_id to BPF_BTF_GET_FD_BY_ID bpf: Return prog btf_id without capable check bpf: BPF token support for BPF_BTF_GET_FD_BY_ID bpf, x86: Fix objtool warning for timed may_goto bpf: Check map->record at the beginning of check_and_free_fields() ... List of files: /linux/tools/bpf/bpftool/Makefile

8d86767be9c9b94f196e663e0ca88e2eb604a20e - bpftool: Add -Wformat-signedness flag to detect format errors

Tue, 11 Mar 2025 12:28:08 +0100

bpftool: Add -Wformat-signedness flag to detect format errorsThis commit adds the -Wformat-signedness compiler flag to detect andprevent printf format errors, where signed or unsigned types aremismatched with format specifiers. This helps to catch potential issues atcompile-time, ensuring that our code is more robust and reliable. Withthis flag, the compiler will now warn about incorrect format strings, suchas using %d with unsigned types or %u with signed types.Signed-off-by: Jiayuan Chen Signed-off-by: Andrii Nakryiko Link: https://lore.kernel.org/bpf/20250311112809.81901-2-jiayuan.chen@linux.dev List of files: /linux/tools/bpf/bpftool/Makefile

42367eca7604e16e170bd6bd94ef61ffdd335f4a - tools: Remove redundant quiet setup

Thu, 13 Feb 2025 22:06:22 +0100

tools: Remove redundant quiet setupQ is exported from Makefile.include so it is not necessary to manuallyset it.Reviewed-by: Jiri Olsa Signed-off-by: Charlie Jenkins Acked-by: Andrii Nakryiko Acked-by: Quentin Monnet Cc: Adrian Hunter Cc: Alexander Shishkin Cc: Alexei Starovoitov Cc: Benjamin Tissoires Cc: Daniel Borkmann Cc: Daniel Lezcano Cc: Eduard Zingerman Cc: Hao Luo Cc: Ian Rogers Cc: Ingo Molnar Cc: Jiri Kosina Cc: John Fastabend Cc: Josh Poimboeuf Cc: KP Singh Cc: Lukasz Luba Cc: Mark Rutland Cc: Martin KaFai Lau Cc: Mykola Lysenko Cc: Namhyung Kim Cc: Peter Zijlstra Cc: Rafael J. Wysocki Cc: Shuah Khan Cc: Song Liu Cc: Stanislav Fomichev Cc: Steven Rostedt (VMware) Cc: Yonghong Song Cc: Zhang Rui Link: https://lore.kernel.org/r/20250213-quiet_tools-v3-2-07de4482a581@rivosinc.comSigned-off-by: Arnaldo Carvalho de Melo List of files: /linux/tools/bpf/bpftool/Makefile

fee9c03b25829adcc5539da1081d6219fe7ccbcd - bpftool: Link zstd lib required by libelf

Sun, 15 Dec 2024 23:12:23 +0100

bpftool: Link zstd lib required by libelfWhen the feature libelf-zstd is detected, the zstd lib is required bylibelf. Link the zstd lib in this case.Reviewed-by: Quentin Monnet Signed-off-by: Leo Yan Tested-by: Namhyung Kim Acked-by: Andrii Nakryiko Cc: Adrian Hunter Cc: Alexei Starovoitov Cc: Daniel Borkmann Cc: Eduard Zingerman Cc: Guilherme Amadio Cc: Hao Luo Cc: Ian Rogers Cc: James Clark Cc: Jiri Olsa Cc: John Fastabend Cc: KP Singh Cc: Kan Liang Cc: Martin KaFai Lau Cc: Nick Terrell Cc: Song Liu Cc: Stanislav Fomichev Cc: Yonghong Song Link: https://lore.kernel.org/r/20241215221223.293205-4-leo.yan@arm.comSigned-off-by: Arnaldo Carvalho de Melo List of files: /linux/tools/bpf/bpftool/Makefile

0513eeee86d67930f3567e450357d8db1cfb4f16 - bpftool: Prevent setting duplicate _GNU_SOURCE in Makefile

Fri, 01 Nov 2024 09:27:12 +0100

bpftool: Prevent setting duplicate _GNU_SOURCE in MakefileWhen building selftests with CFLAGS set via env variable, the value ofCFLAGS is propagated into bpftool Makefile (called from selftestsMakefile). This makes the compilation fail as _GNU_SOURCE is defined twotimes - once from selftests Makefile (by including lib.mk) and once frombpftool Makefile (by calling `llvm-config --cflags`): $ CFLAGS="" make -C tools/testing/selftests/bpf [...] CC /bpf-next/tools/testing/selftests/bpf/tools/build/bpftool/btf.o : error: "_GNU_SOURCE" redefined [-Werror] : note: this is the location of the previous definition cc1: all warnings being treated as errors [...]Filter out -D_GNU_SOURCE from the result of `llvm-config --cflags` inbpftool Makefile to prevent this error.Signed-off-by: Viktor Malik Signed-off-by: Andrii Nakryiko Acked-by: Quentin Monnet Acked-by: Jiri Olsa Link: https://lore.kernel.org/bpf/acec3108b62d4df1436cda777e58e93e033ac7a7.1730449390.git.vmalik@redhat.com List of files: /linux/tools/bpf/bpftool/Makefile

e7b64f9d3f5b10186038201e0b91f734cbd7fc3d - bpftool: Fix make dependencies for vmlinux.h

Mon, 13 May 2024 13:26:58 +0200

bpftool: Fix make dependencies for vmlinux.hWith pre-generated vmlinux.h there is no dependency on neither vmlinuxnor bootstrap bpftool. Define dependencies separately for both modes.This avoids needless rebuilds in some corner cases.Suggested-by: Jan Stancek Signed-off-by: Artem Savkov Signed-off-by: Andrii Nakryiko Acked-by: Quentin Monnet Link: https://lore.kernel.org/bpf/20240513112658.43691-1-asavkov@redhat.comSigned-off-by: Alexei Starovoitov List of files: /linux/tools/bpf/bpftool/Makefile

41b307ad756e1b7b618bf9d9c1cce3595705ede4 - bpftool, selftests/hid/bpf: Fix 29 clang warnings

Mon, 06 May 2024 01:00:54 +0200

bpftool, selftests/hid/bpf: Fix 29 clang warningsWhen building either tools/bpf/bpftool, or tools/testing/selftests/hid,(the same Makefile is used for these), clang generates many instances ofthe following: "clang: warning: -lLLVM-17: 'linker' input unused"Quentin points out that the LLVM version is only required in $(LIBS),not in $(CFLAGS), so the fix is to remove it from CFLAGS.Suggested-by: Quentin Monnet Signed-off-by: John Hubbard Signed-off-by: Andrii Nakryiko Acked-by: Quentin Monnet Link: https://lore.kernel.org/bpf/20240505230054.13813-1-jhubbard@nvidia.com List of files: /linux/tools/bpf/bpftool/Makefile

cc9b22dfa735800980e7362f02aff6f1c2280996 - bpftool: Clean up HOST_CFLAGS, HOST_LDFLAGS for bootstrap bpftool

Wed, 20 Mar 2024 02:41:03 +0100

bpftool: Clean up HOST_CFLAGS, HOST_LDFLAGS for bootstrap bpftoolBpftool's Makefile uses $(HOST_CFLAGS) to build the bootstrap version ofbpftool, in order to pick the flags for the host (where we run thebootstrap version) and not for the target system (where we plan to runthe full bpftool binary). But we pass too much information through thisvariable.In particular, we set HOST_CFLAGS by copying most of the $(CFLAGS); butwe do this after the feature detection for bpftool, which means that$(CFLAGS), hence $(HOST_CFLAGS), contain all macro definitions for usingthe different optional features. For example, -DHAVE_LLVM_SUPPORT may bepassed to the $(HOST_CFLAGS), even though the LLVM disassembler is notused in the bootstrap version, and the related library may even bemissing for the host architecture.A similar thing happens with the $(LDFLAGS), that we use unchanged forlinking the bootstrap version even though they may contains flags tolink against additional libraries.To address the $(HOST_CFLAGS) issue, we move the definition of$(HOST_CFLAGS) earlier in the Makefile, before the $(CFLAGS) updateresulting from the feature probing - none of which being relevant to thebootstrap version. To clean up the $(LDFLAGS) for the bootstrap version,we introduce a dedicated $(HOST_LDFLAGS) variable that we base on$(LDFLAGS), before the feature probing as well.On my setup, the following macro and libraries are removed from thecompiler invocation to build bpftool after this patch: -DUSE_LIBCAP -DHAVE_LLVM_SUPPORT -I/usr/lib/llvm-17/include -D_GNU_SOURCE -D__STDC_CONSTANT_MACROS -D__STDC_FORMAT_MACROS -D__STDC_LIMIT_MACROS -lLLVM-17 -L/usr/lib/llvm-17/libAnother advantage of cleaning up these flags is that displayingavailable features with "bpftool version" becomes more accurate for thebootstrap bpftool, and no longer reflects the features detected (andavailable only) for the final binary.Cc: Jean-Philippe Brucker Signed-off-by: Quentin Monnet Acked-by: Jiri Olsa Message-ID: <20240320014103.45641-1-qmo@kernel.org>Signed-off-by: Alexei Starovoitov List of files: /linux/tools/bpf/bpftool/Makefile

e9a826dd145bf2c19888aee1b974214cefc74a2e - bpftool: Remove unnecessary source files from bootstrap version

Wed, 20 Mar 2024 02:34:57 +0100

bpftool: Remove unnecessary source files from bootstrap versionCommit d510296d331a ("bpftool: Use syscall/loader program in "prog load"and "gen skeleton" command.") added new files to the list of objects tocompile in order to build the bootstrap version of bpftool. As far as Ican tell, these objects are unnecessary and were added by mistake; maybea draft version intended to add support for loading loader programs fromthe bootstrap version. Anyway, we can remove these object files from thelist to make the bootstrap bpftool binary a tad smaller and faster tobuild.Fixes: d510296d331a ("bpftool: Use syscall/loader program in "prog load" and "gen skeleton" command.")Signed-off-by: Quentin Monnet Message-ID: <20240320013457.44808-1-qmo@kernel.org>Signed-off-by: Alexei Starovoitov List of files: /linux/tools/bpf/bpftool/Makefile

bbaf1ff06af49e856501024abbe161d96c1f0d66 - bpf: Replace deprecated -target with --target= for Clang

Sat, 24 Jun 2023 02:18:56 +0200

bpf: Replace deprecated -target with --target= for ClangThe -target option has been deprecated since clang 3.4 in 2013. Therefore, usethe preferred --target=bpf form instead. This also matches how we use --target=in scripts/Makefile.clang.Signed-off-by: Fangrui Song Signed-off-by: Daniel Borkmann Acked-by: Yonghong Song Acked-by: Quentin Monnet Link: https://github.com/llvm/llvm-project/commit/274b6f0c87a6a1798de0a68135afc7f95def6277Link: https://lore.kernel.org/bpf/20230624001856.1903733-1-maskray@google.com List of files: /linux/tools/bpf/bpftool/Makefile

878625e1c7a10dfbb1fdaaaae2c4d2a58fbce627 - bpftool: Always disable stack protection for BPF objects

Fri, 13 Jan 2023 16:40:23 +0100

bpftool: Always disable stack protection for BPF objectsWhen the clang toolchain has stack protection enabled in order to beconsistent with gcc - which just happens to be the case on Gentoo -the bpftool build fails: [...] clang \ -I. \ -I/tmp/portage/dev-util/bpftool-6.0.12/work/linux-6.0/tools/include/uapi/ \ -I/tmp/portage/dev-util/bpftool-6.0.12/work/linux-6.0/tools/bpf/bpftool/bootstrap/libbpf/include \ -g -O2 -Wall -target bpf -c skeleton/pid_iter.bpf.c -o pid_iter.bpf.o clang \ -I. \ -I/tmp/portage/dev-util/bpftool-6.0.12/work/linux-6.0/tools/include/uapi/ \ -I/tmp/portage/dev-util/bpftool-6.0.12/work/linux-6.0/tools/bpf/bpftool/bootstrap/libbpf/include \ -g -O2 -Wall -target bpf -c skeleton/profiler.bpf.c -o profiler.bpf.o skeleton/profiler.bpf.c:40:14: error: A call to built-in function '__stack_chk_fail' is not supported. int BPF_PROG(fentry_XXX) ^ skeleton/profiler.bpf.c:94:14: error: A call to built-in function '__stack_chk_fail' is not supported. int BPF_PROG(fexit_XXX) ^ 2 errors generated. [...]Since stack-protector makes no sense for the BPF bits just unconditionallydisable it.Bug: https://bugs.gentoo.org/890638Signed-off-by: Holger Hoffstätte Signed-off-by: Daniel Borkmann Acked-by: Quentin Monnet Link: https://lore.kernel.org/bpf/74cd9d2e-6052-312a-241e-2b514a75c92c@applied-asynchrony.com List of files: /linux/tools/bpf/bpftool/Makefile

af0e26beaa693cc0cb0472b80a33a5831103d22f - bpftool: Add missing quotes to libbpf bootstrap submake vars

Tue, 10 Jan 2023 02:45:04 +0100

bpftool: Add missing quotes to libbpf bootstrap submake varsWhen passing compiler variables like CC=$(HOSTCC) to a submakewe must ensure the variable is quoted in order to handle caseswhere $(HOSTCC) may be multiple binaries.For example when using ccache $HOSTCC may be:"/usr/bin/ccache /usr/bin/gcc"If we pass CC without quotes like CC=$(HOSTCC) only the first"/usr/bin/ccache" part will be assigned to the CC variable whichwill cause an error due to dropping the "/usr/bin/gcc" part ofthe variable in the submake invocation.This fixes errors such as:/usr/bin/ccache: invalid option -- 'd'Signed-off-by: James Hilliard Signed-off-by: Daniel Borkmann Acked-by: Quentin Monnet Link: https://lore.kernel.org/bpf/20230110014504.3120711-1-james.hilliard1@gmail.com List of files: /linux/tools/bpf/bpftool/Makefile

4aea86b4033f92f01547e6d4388d4451ae9b0980 - Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net

Fri, 06 Jan 2023 00:34:11 +0100

Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/netNo conflicts.Signed-off-by: Jakub Kicinski List of files: /linux/tools/bpf/bpftool/Makefile

55171f2930be98c8a49991435cdf3a8b574353b6 - bpftool: Fix linkage with statically built libllvm

Thu, 22 Dec 2022 11:26:27 +0100

bpftool: Fix linkage with statically built libllvmSince the commit eb9d1acf634b ("bpftool: Add LLVM as default library fordisassembling JIT-ed programs") we might link the bpftool program with thelibllvm library. This works fine when a shared libllvm library is available,but fails if we want to link bpftool with a statically built LLVM: [...] /usr/bin/ld: /usr/local/lib/libLLVMSupport.a(CrashRecoveryContext.cpp.o): in function `llvm::CrashRecoveryContextCleanup::~CrashRecoveryContextCleanup()': CrashRecoveryContext.cpp:(.text._ZN4llvm27CrashRecoveryContextCleanupD0Ev+0x17): undefined reference to `operator delete(void*, unsigned long)' /usr/bin/ld: /usr/local/lib/libLLVMSupport.a(CrashRecoveryContext.cpp.o): in function `llvm::CrashRecoveryContext::~CrashRecoveryContext()': CrashRecoveryContext.cpp:(.text._ZN4llvm20CrashRecoveryContextD2Ev+0xc8): undefined reference to `operator delete(void*, unsigned long)' [...]So in the case of static libllvm we need to explicitly link bpftool withrequired libraries, namely, libstdc++ and those provided by the `llvm-config--system-libs` command. We can distinguish between the shared and static casesby using the `llvm-config --shared-mode` command.Fixes: eb9d1acf634b ("bpftool: Add LLVM as default library for disassembling JIT-ed programs")Signed-off-by: Anton Protopopov Signed-off-by: Daniel Borkmann Acked-by: Stanislav Fomichev Link: https://lore.kernel.org/bpf/20221222102627.1643709-1-aspsk@isovalent.com List of files: /linux/tools/bpf/bpftool/Makefile

e7f0d5cdd023d8fa53d9ca541b9a55f0eb45618c - bpf: makefiles: Do not generate empty vmlinux.h

Sat, 17 Dec 2022 23:35:09 +0100

bpf: makefiles: Do not generate empty vmlinux.hRemove the empty vmlinux.h if bpftool failed to dump btf info.The empty vmlinux.h can hide real error when reading outputof make.This is done by adding .DELETE_ON_ERROR special target in relatedmakefiles.Signed-off-by: Changbin Du Signed-off-by: Andrii Nakryiko Acked-by: Quentin Monnet Link: https://lore.kernel.org/bpf/20221217223509.88254-3-changbin.du@gmail.com List of files: /linux/tools/bpf/bpftool/Makefile

eb9d1acf634baf6401dfb4f67dc895290713a357 - bpftool: Add LLVM as default library for disassembling JIT-ed programs

Tue, 25 Oct 2022 17:03:27 +0200

bpftool: Add LLVM as default library for disassembling JIT-ed programsTo disassemble instructions for JIT-ed programs, bpftool has relied onthe libbfd library. This has been problematic in the past: libbfd'sinterface is not meant to be stable and has changed several times. Forbuilding bpftool, we have to detect how the libbfd version on the systembehaves, which is why we have to handle features disassembler-four-argsand disassembler-init-styled in the Makefile. When it comes to shippingbpftool, this has also caused issues with several distributionmaintainers unwilling to support the feature (see for example Debian'spage for binutils-dev, which ships libbfd: "Note that building Debianpackages which depend on the shared libbfd is Not Allowed." [0]).For these reasons, we add support for LLVM as an alternative to libbfdfor disassembling instructions of JIT-ed programs. Thanks to thepreparation work in the previous commits, it's easy to add the libraryby passing the relevant compilation options in the Makefile, and byadding the functions for setting up the LLVM disassembler in filejit_disasm.c.The LLVM disassembler requires the LLVM development package (usuallyllvm-dev or llvm-devel).The expectation is that the interface for this disassembler will be morestable. There is a note in LLVM's Developer Policy [1] stating that thestability for the C API is "best effort" and not guaranteed, but atleast there is some effort to keep compatibility when possible (whichhasn't really been the case for libbfd so far). Furthermore, the Debianpage for the related LLVM package does not caution against linking tothe lib, as binutils-dev page does.Naturally, the display of disassembled instructions comes with a fewminor differences. Here is a sample output with libbfd (alreadysupported 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: retLLVM supports several variants that we could set when initialising thedisassembler, 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: retqThe LLVM disassembler comes as the default choice, with libbfd as afall-back.Of course, we could replace libbfd entirely and avoid supporting twodifferent libraries. One reason for keeping libbfd is that, right now,it works well, we have all we need in terms of features detection in theMakefile, so it provides a fallback for disassembling JIT-ed programs iflibbfd is installed but LLVM is not. The other motivation is that libbfdsupports nfp instruction for Netronome's SmartNICs and can be used todisassemble offloaded programs, something that LLVM cannot do. Iflibbfd's interface breaks again in the future, we might reconsiderkeeping support for it.[0] https://packages.debian.org/buster/binutils-dev[1] https://llvm.org/docs/DeveloperPolicy.html#c-api-changesSigned-off-by: Quentin Monnet Tested-by: Niklas Söderlund Acked-by: Yonghong Song Link: https://lore.kernel.org/r/20221025150329.97371-7-quentin@isovalent.comSigned-off-by: Alexei Starovoitov List of files: /linux/tools/bpf/bpftool/Makefile