kernel/linux.git/tools/bpf/bpftool/Makefile, branch v6.6.134

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

2023-06-29T13:46:17+00:00

The -target option has been deprecated since clang 3.4 in 2013. Therefore, use the 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/274b6f0c87a6a1798de0a68135afc7f95def6277 Link: https://lore.kernel.org/bpf/20230624001856.1903733-1-maskray@google.com

bpftool: Always disable stack protection for BPF objects

2023-01-13T15:44:21+00:00

When the clang toolchain has stack protection enabled in order to be consistent 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 unconditionally disable it. Bug: https://bugs.gentoo.org/890638 Signed-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

bpftool: Add missing quotes to libbpf bootstrap submake vars

2023-01-10T22:12:47+00:00

When passing compiler variables like CC=$(HOSTCC) to a submake we must ensure the variable is quoted in order to handle cases where $(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 which will cause an error due to dropping the "/usr/bin/gcc" part of the 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

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

2023-01-05T23:34:11+00:00

No conflicts. Signed-off-by: Jakub Kicinski

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

bpf: makefiles: Do not generate empty vmlinux.h

2022-12-21T00:09:39+00:00

Remove the empty vmlinux.h if bpftool failed to dump btf info. The empty vmlinux.h can hide real error when reading output of make. This is done by adding .DELETE_ON_ERROR special target in related makefiles. 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

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