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

bpftool: Remove inclusion of utilities.mak from Makefiles

2022-01-27T11:02:54Z

commit 48f5aef4c458c19ab337eed8c95a6486cc014aa3 upstream. Bpftool's Makefile, and the Makefile for its documentation, both include scripts/utilities.mak, but they use none of the items defined in this file. Remove the includes. Fixes: 71bb428fe2c1 ("tools: bpf: add bpftool") Signed-off-by: Quentin Monnet Signed-off-by: Andrii Nakryiko Link: https://lore.kernel.org/bpf/20211110114632.24537-3-quentin@isovalent.com Signed-off-by: Greg Kroah-Hartman

bpftool: Install libbpf headers for the bootstrap version, too

2021-11-05T15:19:48Z

We recently changed bpftool's Makefile to make it install libbpf's headers locally instead of pulling them from the source directory of the library. Although bpftool needs two versions of libbpf, a "regular" one and a "bootstrap" version, we would only install headers for the regular libbpf build. Given that this build always occurs before the bootstrap build when building bpftool, this is enough to ensure that the bootstrap bpftool will have access to the headers exported through the regular libbpf build. However, this did not account for the case when we only want the bootstrap version of bpftool, through the "bootstrap" target. For example, perf needs the bootstrap version only, to generate BPF skeletons. In that case, when are the headers installed? For some time, the issue has been masked, because we had a step (the installation of headers internal to libbpf) which would depend on the regular build of libbpf and hence trigger the export of the headers, just for the sake of creating a directory. But this changed with commit 8b6c46241c77 ("bpftool: Remove Makefile dep. on $(LIBBPF) for $(LIBBPF_INTERNAL_HDRS)"), where we cleaned up that stage and removed the dependency on the regular libbpf build. As a result, when we only want the bootstrap bpftool version, the regular libbpf is no longer built. The bootstrap libbpf version is built, but headers are not exported, and the bootstrap bpftool build fails because of the missing headers. To fix this, we also install the library headers for the bootstrap version of libbpf, to use them for the bootstrap bpftool and for generating the skeletons. Fixes: f012ade10b34 ("bpftool: Install libbpf headers instead of including the dir") Reported-by: Arnaldo Carvalho de Melo Signed-off-by: Quentin Monnet Signed-off-by: Daniel Borkmann Tested-by: Arnaldo Carvalho de Melo Link: https://lore.kernel.org/bpf/20211105015813.6171-1-quentin@isovalent.com

bpftool: Switch to libbpf's hashmap for pinned paths of BPF objects

2021-10-26T00:31:38Z

In order to show pinned paths for BPF programs, maps, or links when listing them with the "-f" option, bpftool creates hash maps to store all relevant paths under the bpffs. So far, it would rely on the kernel implementation (from tools/include/linux/hashtable.h). We can make bpftool rely on libbpf's implementation instead. The motivation is to make bpftool less dependent of kernel headers, to ease the path to a potential out-of-tree mirror, like libbpf has. This commit is the first step of the conversion: the hash maps for pinned paths for programs, maps, and links are converted to libbpf's hashmap.{c,h}. Other hash maps used for the PIDs of process holding references to BPF objects are left unchanged for now. On the build side, this requires adding a dependency to a second header internal to libbpf, and making it a dependency for the bootstrap bpftool version as well. The rest of the changes are a rather straightforward conversion. Signed-off-by: Quentin Monnet Signed-off-by: Andrii Nakryiko Link: https://lore.kernel.org/bpf/20211023205154.6710-4-quentin@isovalent.com

bpftool: Remove Makefile dep. on $(LIBBPF) for $(LIBBPF_INTERNAL_HDRS)

2021-10-26T00:31:38Z

The dependency is only useful to make sure that the $(LIBBPF_HDRS_DIR) directory is created before we try to install locally the required libbpf internal header. Let's create this directory properly instead. This is in preparation of making $(LIBBPF_INTERNAL_HDRS) a dependency to the bootstrap bpftool version, in which case we want no dependency on $(LIBBPF). Signed-off-by: Quentin Monnet Signed-off-by: Andrii Nakryiko Link: https://lore.kernel.org/bpf/20211023205154.6710-2-quentin@isovalent.com

bpftool: Remove useless #include to from map_perf_ring.c

2021-10-20T17:47:39Z

The header is no longer needed since the event_pipe implementation was updated to rely on libbpf's perf_buffer. This makes bpftool free of dependencies to perf files, and we can update the Makefile accordingly. Fixes: 9b190f185d2f ("tools/bpftool: switch map event_pipe to libbpf's perf_buffer") Signed-off-by: Quentin Monnet Signed-off-by: Andrii Nakryiko Link: https://lore.kernel.org/bpf/20211020094826.16046-1-quentin@isovalent.com

bpftool: Turn check on zlib from a phony target into a conditional error

2021-10-19T23:41:50Z

One of bpftool's object files depends on zlib. To make sure we do not attempt to build that object when the library is not available, commit d66fa3c70e59 ("tools: bpftool: add feature check for zlib") introduced a feature check to detect whether zlib is present. This check comes as a rule for which the target ("zdep") is a nonexistent file (phony target), which means that the Makefile always attempts to rebuild it. It is mostly harmless. However, one side effect is that, on running again once bpftool is already built, make considers that "something" (the recipe for zdep) was executed, and does not print the usual message "make: Nothing to be done for 'all'", which is a user-friendly indicator that the build went fine. Before, with some level of debugging information: $ make --debug=m [...] Reading makefiles... Auto-detecting system features: ... libbfd: [ on ] ... disassembler-four-args: [ on ] ... zlib: [ on ] ... libcap: [ on ] ... clang-bpf-co-re: [ on ] Updating makefiles.... Updating goal targets.... File 'all' does not exist. File 'zdep' does not exist. Must remake target 'zdep'. File 'all' does not exist. Must remake target 'all'. Successfully remade target file 'all'. After the patch: $ make --debug=m [...] Auto-detecting system features: ... libbfd: [ on ] ... disassembler-four-args: [ on ] ... zlib: [ on ] ... libcap: [ on ] ... clang-bpf-co-re: [ on ] Updating makefiles.... Updating goal targets.... File 'all' does not exist. Must remake target 'all'. Successfully remade target file 'all'. make: Nothing to be done for 'all'. (Note the last line, which is not part of make's debug information.) Signed-off-by: Quentin Monnet Signed-off-by: Andrii Nakryiko Acked-by: John Fastabend Link: https://lore.kernel.org/bpf/20211009210341.6291-4-quentin@isovalent.com

bpftool: Do not FORCE-build libbpf

2021-10-19T23:41:37Z

In bpftool's Makefile, libbpf has a FORCE dependency, to make sure we rebuild it in case its source files changed. Let's instead make the rebuild depend on the source files directly, through a call to the "$(wildcard ...)" function. This avoids descending into libbpf's directory if there is nothing to update. Do the same for the bootstrap libbpf version. This results in a slightly faster operation and less verbose output when running make a second time in bpftool's directory. Before: Auto-detecting system features: ... libbfd: [ on ] ... disassembler-four-args: [ on ] ... zlib: [ on ] ... libcap: [ on ] ... clang-bpf-co-re: [ on ] make[1]: Entering directory '/root/dev/linux/tools/lib/bpf' make[1]: Entering directory '/root/dev/linux/tools/lib/bpf' make[1]: Nothing to be done for 'install_headers'. make[1]: Leaving directory '/root/dev/linux/tools/lib/bpf' make[1]: Leaving directory '/root/dev/linux/tools/lib/bpf' After: Auto-detecting system features: ... libbfd: [ on ] ... disassembler-four-args: [ on ] ... zlib: [ on ] ... libcap: [ on ] ... clang-bpf-co-re: [ on ] Other ways to clean up the output could be to pass the "-s" option, or to redirect the output to >/dev/null, when calling make recursively to descend into libbpf's directory. However, this would suppress some useful output if something goes wrong during the build. A better alternative would be to pass "--no-print-directory" to the recursive make, but that would still leave us with some noise for "install_headers". Skipping the descent into libbpf's directory if no source file has changed works best, and seems the most logical option overall. Reported-by: Andrii Nakryiko Signed-off-by: Quentin Monnet Signed-off-by: Andrii Nakryiko Acked-by: John Fastabend Link: https://lore.kernel.org/bpf/20211009210341.6291-3-quentin@isovalent.com

bpftool: Fix install for libbpf's internal header(s)

2021-10-19T23:40:42Z

We recently updated bpftool's Makefile to make it install the headers from libbpf, instead of pulling them directly from libbpf's directory. There is also an additional header, internal to libbpf, that needs be installed. The way that bpftool's Makefile installs that particular header is currently correct, but would break if we were to modify $(LIBBPF_INTERNAL_HDRS) to make it point to more than one header. Use a static pattern rule instead, so that the Makefile can withstand the addition of other headers to install. The objective is simply to make the Makefile more robust. It should _not_ be read as an invitation to import more internal headers from libbpf into bpftool. Fixes: f012ade10b34 ("bpftool: Install libbpf headers instead of including the dir") Reported-by: Andrii Nakryiko Signed-off-by: Quentin Monnet Signed-off-by: Andrii Nakryiko Acked-by: John Fastabend Link: https://lore.kernel.org/bpf/20211009210341.6291-2-quentin@isovalent.com

bpftool: Add install-bin target to install binary only

2021-10-08T19:02:40Z

With "make install", bpftool installs its binary and its bash completion file. Usually, this is what we want. But a few components in the kernel repository (namely, BPF iterators and selftests) also install bpftool locally before using it. In such a case, bash completion is not necessary and is just a useless build artifact. Let's add an "install-bin" target to bpftool, to offer a way to install the binary only. Signed-off-by: Quentin Monnet Signed-off-by: Andrii Nakryiko Link: https://lore.kernel.org/bpf/20211007194438.34443-13-quentin@isovalent.com

bpftool: Install libbpf headers instead of including the dir

2021-10-08T18:48:43Z

Bpftool relies on libbpf, therefore it relies on a number of headers from the library and must be linked against the library. The Makefile for bpftool exposes these objects by adding tools/lib as an include directory ("-I$(srctree)/tools/lib"). This is a working solution, but this is not the cleanest one. The risk is to involuntarily include objects that are not intended to be exposed by the libbpf. The headers needed to compile bpftool should in fact be "installed" from libbpf, with its "install_headers" Makefile target. In addition, there is one header which is internal to the library and not supposed to be used by external applications, but that bpftool uses anyway. Adjust the Makefile in order to install the header files properly before compiling bpftool. Also copy the additional internal header file (nlattr.h), but call it out explicitly. Build (and install headers) in a subdirectory under bpftool/ instead of tools/lib/bpf/. When descending from a parent Makefile, this is configurable by setting the OUTPUT, LIBBPF_OUTPUT and LIBBPF_DESTDIR variables. Also adjust the Makefile for BPF selftests, so as to reuse the (host) libbpf compiled earlier and to avoid compiling a separate version of the library just for bpftool. Signed-off-by: Quentin Monnet Signed-off-by: Andrii Nakryiko Acked-by: Andrii Nakryiko Link: https://lore.kernel.org/bpf/20211007194438.34443-4-quentin@isovalent.com