kernel/linux.git/tools/bpf/bpftool/Makefile, branch v6.2.2

bpftool: Fix linkage with statically built libllvm

2022-12-22T19:09:43+00:00

Since the commit eb9d1acf634b ("bpftool: Add LLVM as default library for disassembling JIT-ed programs") we might link the bpftool program with the libllvm 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 with required libraries, namely, libstdc++ and those provided by the `llvm-config --system-libs` command. We can distinguish between the shared and static cases by 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

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

2022-10-25T17:11:56+00:00

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

bpftool: Group libbfd defs in Makefile, only pass them if we use libbfd

2022-10-25T17:11:56+00:00

Bpftool uses libbfd for disassembling JIT-ed programs. But the feature is optional, and the tool can be compiled without libbfd support. The Makefile sets the relevant variables accordingly. It also sets variables related to libbfd's interface, given that it has changed over time. Group all those libbfd-related definitions so that it's easier to understand what we are testing for, and only use variables related to libbfd's interface if we need libbfd in the first place. In addition to make the Makefile clearer, grouping the definitions related to disassembling JIT-ed programs will help support alternatives to libbfd. Signed-off-by: Quentin Monnet Tested-by: Niklas Söderlund Acked-by: Song Liu Link: https://lore.kernel.org/r/20221025150329.97371-5-quentin@isovalent.com Signed-off-by: Alexei Starovoitov

bpftool: Split FEATURE_TESTS/FEATURE_DISPLAY definitions in Makefile

2022-10-25T17:11:56+00:00

Make FEATURE_TESTS and FEATURE_DISPLAY easier to read and less likely to be subject to conflicts on updates by having one feature per line. Suggested-by: Andres Freund Signed-off-by: Quentin Monnet Tested-by: Niklas Söderlund Acked-by: Song Liu Link: https://lore.kernel.org/r/20221025150329.97371-4-quentin@isovalent.com Signed-off-by: Alexei Starovoitov

bpftool: Complete libbfd feature detection

2022-08-10T13:44:01+00:00

Commit 6e8ccb4f624a7 ("tools/bpf: properly account for libbfd variations") sets the linking flags depending on which flavor of the libbfd feature was detected. However, the flavors except libbfd cannot be detected, as they are not in the feature list. Complete the list of features to detect by adding libbfd-liberty and libbfd-liberty-z. Committer notes: Adjust conflict with with: 1e1613f64cc8a09d ("tools bpftool: Don't display disassembler-four-args feature test") 600b7b26c07a070d ("tools bpftool: Fix compilation error with new binutils") Fixes: 6e8ccb4f624a73c5 ("tools/bpf: properly account for libbfd variations") Signed-off-by: Roberto Sassu Cc: Alexei Starovoitov Cc: Andres Freund Cc: Andrii Nakryiko Cc: bpf@vger.kernel.org Cc: Daniel Borkmann Cc: Ingo Molnar Cc: John Fastabend Cc: KP Singh Cc: llvm@lists.linux.dev Cc: Martin KaFai Lau Cc: Nathan Chancellor Cc: Nick Desaulniers Cc: Nick Terrell Cc: Peter Zijlstra Cc: Quentin Monnet Cc: Song Liu Cc: Stanislav Fomichev Link: https://lore.kernel.org/r/20220719170555.2576993-2-roberto.sassu@huawei.com Signed-off-by: Arnaldo Carvalho de Melo

Merge tag 'perf-tools-for-v6.0-2022-08-04' of git://git.kernel.org/pub/scm/linux/kernel/git/acme/linux

2022-08-06T16:36:08+00:00

Pull perf tools updates from Arnaldo Carvalho de Melo: - Introduce 'perf lock contention' subtool, using new lock contention tracepoints and using BPF for in kernel aggregation and then userspace processing using the perf tooling infrastructure for resolving symbols, target specification, etc. Since the new lock contention tracepoints don't provide lock names, get up to 8 stack traces and display the first non-lock function symbol name as a caller: $ perf lock report -F acquired,contended,avg_wait,wait_total Name acquired contended avg wait total wait update_blocked_a... 40 40 3.61 us 144.45 us kernfs_fop_open+... 5 5 3.64 us 18.18 us _nohz_idle_balance 3 3 2.65 us 7.95 us tick_do_update_j... 1 1 6.04 us 6.04 us ep_scan_ready_list 1 1 3.93 us 3.93 us Supports the usual 'perf record' + 'perf report' workflow as well as a BCC/bpftrace like mode where you start the tool and then press control+C to get results: $ sudo perf lock contention -b ^C contended total wait max wait avg wait type caller 42 192.67 us 13.64 us 4.59 us spinlock queue_work_on+0x20 23 85.54 us 10.28 us 3.72 us spinlock worker_thread+0x14a 6 13.92 us 6.51 us 2.32 us mutex kernfs_iop_permission+0x30 3 11.59 us 10.04 us 3.86 us mutex kernfs_dop_revalidate+0x3c 1 7.52 us 7.52 us 7.52 us spinlock kthread+0x115 1 7.24 us 7.24 us 7.24 us rwlock:W sys_epoll_wait+0x148 2 7.08 us 3.99 us 3.54 us spinlock delayed_work_timer_fn+0x1b 1 6.41 us 6.41 us 6.41 us spinlock idle_balance+0xa06 2 2.50 us 1.83 us 1.25 us mutex kernfs_iop_lookup+0x2f 1 1.71 us 1.71 us 1.71 us mutex kernfs_iop_getattr+0x2c ... - Add new 'perf kwork' tool to trace time properties of kernel work (such as softirq, and workqueue), uses eBPF skeletons to collect info in kernel space, aggregating data that then gets processed by the userspace tool, e.g.: # perf kwork report Kwork Name | Cpu | Total Runtime | Count | Max runtime | Max runtime start | Max runtime end | ---------------------------------------------------------------------------------------------------- nvme0q5:130 | 004 | 1.101 ms | 49 | 0.051 ms | 26035.056403 s | 26035.056455 s | amdgpu:162 | 002 | 0.176 ms | 9 | 0.046 ms | 26035.268020 s | 26035.268066 s | nvme0q24:149 | 023 | 0.161 ms | 55 | 0.009 ms | 26035.655280 s | 26035.655288 s | nvme0q20:145 | 019 | 0.090 ms | 33 | 0.014 ms | 26035.939018 s | 26035.939032 s | nvme0q31:156 | 030 | 0.075 ms | 21 | 0.010 ms | 26035.052237 s | 26035.052247 s | nvme0q8:133 | 007 | 0.062 ms | 12 | 0.021 ms | 26035.416840 s | 26035.416861 s | nvme0q6:131 | 005 | 0.054 ms | 22 | 0.010 ms | 26035.199919 s | 26035.199929 s | nvme0q19:144 | 018 | 0.052 ms | 14 | 0.010 ms | 26035.110615 s | 26035.110625 s | nvme0q7:132 | 006 | 0.049 ms | 13 | 0.007 ms | 26035.125180 s | 26035.125187 s | nvme0q18:143 | 017 | 0.033 ms | 14 | 0.007 ms | 26035.169698 s | 26035.169705 s | nvme0q17:142 | 016 | 0.013 ms | 1 | 0.013 ms | 26035.565147 s | 26035.565160 s | enp5s0-rx-0:164 | 006 | 0.004 ms | 4 | 0.002 ms | 26035.928882 s | 26035.928884 s | enp5s0-tx-0:166 | 008 | 0.003 ms | 3 | 0.002 ms | 26035.870923 s | 26035.870925 s | -------------------------------------------------------------------------------------------------------- See commit log messages for more examples with extra options to limit the events time window, etc. - Add support for new AMD IBS (Instruction Based Sampling) features: With the DataSrc extensions, the source of data can be decoded among: - Local L3 or other L1/L2 in CCX. - A peer cache in a near CCX. - Data returned from DRAM. - A peer cache in a far CCX. - DRAM address map with "long latency" bit set. - Data returned from MMIO/Config/PCI/APIC. - Extension Memory (S-Link, GenZ, etc - identified by the CS target and/or address map at DF's choice). - Peer Agent Memory. - Support hardware tracing with Intel PT on guest machines, combining the traces with the ones in the host machine. - Add a "-m" option to 'perf buildid-list' to show kernel and modules build-ids, to display all of the information needed to do external symbolization of kernel stack traces, such as those collected by bpf_get_stackid(). - Add arch TSC frequency information to perf.data file headers. - Handle changes in the binutils disassembler function signatures in perf, bpftool and bpf_jit_disasm (Acked by the bpftool maintainer). - Fix building the perf perl binding with the newest gcc in distros such as fedora rawhide, where some new warnings were breaking the build as perf uses -Werror. - Add 'perf test' entry for branch stack sampling. - Add ARM SPE system wide 'perf test' entry. - Add user space counter reading tests to 'perf test'. - Build with python3 by default, if available. - Add python converter script for the vendor JSON event files. - Update vendor JSON files for most Intel cores. - Add vendor JSON File for Intel meteorlake. - Add Arm Cortex-A78C and X1C JSON vendor event files. - Add workaround to symbol address reading from ELF files without phdr, falling back to the previoous equation. - Convert legacy map definition to BTF-defined in the perf BPF script test. - Rework prologue generation code to stop using libbpf deprecated APIs. - Add default hybrid events for 'perf stat' on x86. - Add topdown metrics in the default 'perf stat' on the hybrid machines (big/little cores). - Prefer sampled CPU when exporting JSON in 'perf data convert' - Fix ('perf stat CSV output linter') and ("Check branch stack sampling") 'perf test' entries on s390. * tag 'perf-tools-for-v6.0-2022-08-04' of git://git.kernel.org/pub/scm/linux/kernel/git/acme/linux: (169 commits) perf stat: Refactor __run_perf_stat() common code perf lock: Print the number of lost entries for BPF perf lock: Add --map-nr-entries option perf lock: Introduce struct lock_contention perf scripting python: Do not build fail on deprecation warnings genelf: Use HAVE_LIBCRYPTO_SUPPORT, not the never defined HAVE_LIBCRYPTO perf build: Suppress openssl v3 deprecation warnings in libcrypto feature test perf parse-events: Break out tracepoint and printing perf parse-events: Don't #define YY_EXTRA_TYPE tools bpftool: Don't display disassembler-four-args feature test tools bpftool: Fix compilation error with new binutils tools bpf_jit_disasm: Don't display disassembler-four-args feature test tools bpf_jit_disasm: Fix compilation error with new binutils tools perf: Fix compilation error with new binutils tools include: add dis-asm-compat.h to handle version differences tools build: Don't display disassembler-four-args feature test tools build: Add feature test for init_disassemble_info API changes perf test: Add ARM SPE system wide test perf tools: Rework prologue generation code perf bpf: Convert legacy map definition to BTF-defined ...

tools bpftool: Don't display disassembler-four-args feature test

2022-08-01T18:34:05+00:00

The feature check does not seem important enough to display. Requested-by: Jiri Olsa Signed-off-by: Andres Freund Acked-by: Quentin Monnet Tested-by: Arnaldo Carvalho de Melo Cc: Alexei Starovoitov Cc: Ben Hutchings Cc: Quentin Monnet Cc: Sedat Dilek Cc: bpf@vger.kernel.org Link: http://lore.kernel.org/lkml/20220622181918.ykrs5rsnmx3og4sv@alap3.anarazel.de Link: https://lore.kernel.org/r/20220801013834.156015-9-andres@anarazel.de Signed-off-by: Arnaldo Carvalho de Melo

tools bpftool: Fix compilation error with new binutils

2022-08-01T18:32:46+00:00

binutils changed the signature of init_disassemble_info(), which now causes compilation to fail for tools/bpf/bpftool/jit_disasm.c, e.g. on debian unstable. Relevant binutils commit: https://sourceware.org/git/?p=binutils-gdb.git;a=commit;h=60a3da00bd5407f07 Wire up the feature test and switch to init_disassemble_info_compat(), which were introduced in prior commits, fixing the compilation failure. I verified that bpftool can still disassemble bpf programs, both with an old and new dis-asm.h API. There are no output changes for plain and json formats. When comparing the output from old binutils (2.35) to new bintuils with the patch (upstream snapshot) there are a few output differences, but they are unrelated to this patch. An example hunk is: 2f: pop %r14 31: pop %r13 33: pop %rbx - 34: leaveq - 35: retq + 34: leave + 35: ret Signed-off-by: Andres Freund Acked-by: Quentin Monnet Cc: Alexei Starovoitov Cc: Ben Hutchings Cc: Jiri Olsa Cc: Quentin Monnet Cc: Sedat Dilek Cc: bpf@vger.kernel.org Link: http://lore.kernel.org/lkml/20220622181918.ykrs5rsnmx3og4sv@alap3.anarazel.de Link: https://lore.kernel.org/r/20220801013834.156015-8-andres@anarazel.de Signed-off-by: Arnaldo Carvalho de Melo

bpftool: Remove zlib feature test from Makefile

2022-07-06T05:31:17+00:00

The feature test to detect the availability of zlib in bpftool's Makefile does not bring much. The library is not optional: it may or may not be required along libbfd for disassembling instructions, but in any case it is necessary to build feature.o or even libbpf, on which bpftool depends. If we remove the feature test, we lose the nicely formatted error message, but we get a compiler error about "zlib.h: No such file or directory", which is equally informative. Let's get rid of the test. Suggested-by: Andrii Nakryiko Signed-off-by: Quentin Monnet Signed-off-by: Andrii Nakryiko Link: https://lore.kernel.org/bpf/20220705200456.285943-1-quentin@isovalent.com

bpftool: Fix bootstrapping during a cross compilation

2022-06-09T12:01:21+00:00

This change adjusts the Makefile to use "HOSTAR" as the archive tool to keep the sanity of the build process for the bootstrap part in check. For the rationale, please continue reading. When cross compiling bpftool with buildroot, it leads to an invocation like: $ AR="/path/to/buildroot/host/bin/arc-linux-gcc-ar" \ CC="/path/to/buildroot/host/bin/arc-linux-gcc" \ ... make Which in return fails while building the bootstrap section: ----------------------------------8<---------------------------------- make: Entering directory '/src/bpftool-v6.7.0/src' ... libbfd: [ on ] ... disassembler-four-args: [ on ] ... zlib: [ on ] ... libcap: [ OFF ] ... clang-bpf-co-re: [ on ] <-- triggers bootstrap . . . LINK /src/bpftool-v6.7.0/src/bootstrap/bpftool /usr/bin/ld: /src/bpftool-v6.7.0/src/bootstrap/libbpf/libbpf.a: error adding symbols: archive has no index; run ranlib to add one collect2: error: ld returned 1 exit status make: *** [Makefile:211: /src/bpftool-v6.7.0/src/bootstrap/bpftool] Error 1 make: *** Waiting for unfinished jobs.... AR /src/bpftool-v6.7.0/src/libbpf/libbpf.a make[1]: Leaving directory '/src/bpftool-v6.7.0/libbpf/src' make: Leaving directory '/src/bpftool-v6.7.0/src' ---------------------------------->8---------------------------------- This occurs because setting "AR" confuses the build process for the bootstrap section and it calls "arc-linux-gcc-ar" to create and index "libbpf.a" instead of the host "ar". Signed-off-by: Shahab Vahedi Signed-off-by: Daniel Borkmann Reviewed-by: Quentin Monnet Cc: Jean-Philippe Brucker Link: https://lore.kernel.org/bpf/8d297f0c-cfd0-ef6f-3970-6dddb3d9a87a@synopsys.com