linux.git/tools/bpf/bpftool/Makefile, branch v5.9

tools/bpftool: Support passing BPFTOOL_VERSION to make

2020-09-18T23:06:05+00:00

This change facilitates out-of-tree builds, packaging, and versioning for
test and debug purposes. Defining BPFTOOL_VERSION allows self-contained
builds within the tools tree, since it avoids use of the 'kernelversion'
target in the top-level makefile, which would otherwise pull in several
other includes from outside the tools tree.

Signed-off-by: Tony Ambardar 
Signed-off-by: Daniel Borkmann 
Acked-by: Quentin Monnet 
Acked-by: Song Liu 
Link: https://lore.kernel.org/bpf/20200917115833.1235518-1-Tony.Ambardar@gmail.com

tools/bpftool: Strip BPF .o files before skeleton generation

2020-07-26T03:15:32+00:00

Strip away DWARF info from .bpf.o files, before generating BPF skeletons.
This reduces bpftool binary size from 3.43MB to 2.58MB.

Signed-off-by: Andrii Nakryiko 
Signed-off-by: Alexei Starovoitov 
Acked-by: Quentin Monnet 
Link: https://lore.kernel.org/bpf/20200722043804.2373298-1-andriin@fb.com

tools/bpftool: Turn off -Wnested-externs warning

2020-07-01T22:18:28+00:00

Turn off -Wnested-externs to avoid annoying warnings in BUILD_BUG_ON macro when
compiling bpftool:

In file included from /data/users/andriin/linux/tools/include/linux/build_bug.h:5,
                 from /data/users/andriin/linux/tools/include/linux/kernel.h:8,
                 from /data/users/andriin/linux/kernel/bpf/disasm.h:10,
                 from /data/users/andriin/linux/kernel/bpf/disasm.c:8:
/data/users/andriin/linux/kernel/bpf/disasm.c: In function ‘__func_get_name’:
/data/users/andriin/linux/tools/include/linux/compiler.h:37:38: warning: nested extern declaration of ‘__compiletime_assert_0’ [-Wnested-externs]
  _compiletime_assert(condition, msg, __compiletime_assert_, __COUNTER__)
                                      ^~~~~~~~~~~~~~~~~~~~~
/data/users/andriin/linux/tools/include/linux/compiler.h:16:15: note: in definition of macro ‘__compiletime_assert’
   extern void prefix ## suffix(void) __compiletime_error(msg); \
               ^~~~~~
/data/users/andriin/linux/tools/include/linux/compiler.h:37:2: note: in expansion of macro ‘_compiletime_assert’
  _compiletime_assert(condition, msg, __compiletime_assert_, __COUNTER__)
  ^~~~~~~~~~~~~~~~~~~
/data/users/andriin/linux/tools/include/linux/build_bug.h:39:37: note: in expansion of macro ‘compiletime_assert’
 #define BUILD_BUG_ON_MSG(cond, msg) compiletime_assert(!(cond), msg)
                                     ^~~~~~~~~~~~~~~~~~
/data/users/andriin/linux/tools/include/linux/build_bug.h:50:2: note: in expansion of macro ‘BUILD_BUG_ON_MSG’
  BUILD_BUG_ON_MSG(condition, "BUILD_BUG_ON failed: " #condition)
  ^~~~~~~~~~~~~~~~
/data/users/andriin/linux/kernel/bpf/disasm.c:20:2: note: in expansion of macro ‘BUILD_BUG_ON’
  BUILD_BUG_ON(ARRAY_SIZE(func_id_str) != __BPF_FUNC_MAX_ID);
  ^~~~~~~~~~~~

Signed-off-by: Andrii Nakryiko 
Signed-off-by: Daniel Borkmann 
Link: https://lore.kernel.org/bpf/20200701212816.2072340-1-andriin@fb.com

tools/bpftool: Allow substituting custom vmlinux.h for the build

2020-06-30T22:50:11+00:00

In some build contexts (e.g., Travis CI build for outdated kernel), vmlinux.h,
generated from available kernel, doesn't contain all the types necessary for
BPF program compilation. For such set up, the most maintainable way to deal
with this problem is to keep pre-generated (almost up-to-date) vmlinux.h
checked in and use it for compilation purposes. bpftool after that can deal
with kernel missing some of the features in runtime with no problems.

To that effect, allow to specify path to custom vmlinux.h to bpftool's
Makefile with VMLINUX_H variable.

Signed-off-by: Andrii Nakryiko 
Signed-off-by: Alexei Starovoitov 
Acked-by: Yonghong Song 
Link: https://lore.kernel.org/bpf/20200630004759.521530-1-andriin@fb.com

tools, bpftool: Correctly evaluate $(BUILD_BPF_SKELS) in Makefile

2020-06-23T22:06:46+00:00

Currently, if the clang-bpf-co-re feature is not available, the build
fails with e.g.

  CC       prog.o
prog.c:1462:10: fatal error: profiler.skel.h: No such file or directory
 1462 | #include "profiler.skel.h"
      |          ^~~~~~~~~~~~~~~~~

This is due to the fact that the BPFTOOL_WITHOUT_SKELETONS macro is not
defined, despite BUILD_BPF_SKELS not being set. Fix this by correctly
evaluating $(BUILD_BPF_SKELS) when deciding on whether to add
-DBPFTOOL_WITHOUT_SKELETONS to CFLAGS.

Fixes: 05aca6da3b5a ("tools/bpftool: Generalize BPF skeleton support and generate vmlinux.h")
Signed-off-by: Tobias Klauser 
Signed-off-by: Daniel Borkmann 
Reviewed-by: Quentin Monnet 
Acked-by: Andrii Nakryiko 
Link: https://lore.kernel.org/bpf/20200623103710.10370-1-tklauser@distanz.ch

tools/bpftool: Show info for processes holding BPF map/prog/link/btf FDs

2020-06-23T00:01:49+00:00

Add bpf_iter-based way to find all the processes that hold open FDs against
BPF object (map, prog, link, btf). bpftool always attempts to discover this,
but will silently give up if kernel doesn't yet support bpf_iter BPF programs.
Process name and PID are emitted for each process (task group).

Sample output for each of 4 BPF objects:

$ sudo ./bpftool prog show
2694: cgroup_device  tag 8c42dee26e8cd4c2  gpl
        loaded_at 2020-06-16T15:34:32-0700  uid 0
        xlated 648B  jited 409B  memlock 4096B
        pids systemd(1)
2907: cgroup_skb  name egress  tag 9ad187367cf2b9e8  gpl
        loaded_at 2020-06-16T18:06:54-0700  uid 0
        xlated 48B  jited 59B  memlock 4096B  map_ids 2436
        btf_id 1202
        pids test_progs(2238417), test_progs(2238445)

$ sudo ./bpftool map show
2436: array  name test_cgr.bss  flags 0x400
        key 4B  value 8B  max_entries 1  memlock 8192B
        btf_id 1202
        pids test_progs(2238417), test_progs(2238445)
2445: array  name pid_iter.rodata  flags 0x480
        key 4B  value 4B  max_entries 1  memlock 8192B
        btf_id 1214  frozen
        pids bpftool(2239612)

$ sudo ./bpftool link show
61: cgroup  prog 2908
        cgroup_id 375301  attach_type egress
        pids test_progs(2238417), test_progs(2238445)
62: cgroup  prog 2908
        cgroup_id 375344  attach_type egress
        pids test_progs(2238417), test_progs(2238445)

$ sudo ./bpftool btf show
1202: size 1527B  prog_ids 2908,2907  map_ids 2436
        pids test_progs(2238417), test_progs(2238445)
1242: size 34684B
        pids bpftool(2258892)

Signed-off-by: Andrii Nakryiko 
Signed-off-by: Alexei Starovoitov 
Reviewed-by: Quentin Monnet 
Link: https://lore.kernel.org/bpf/20200619231703.738941-9-andriin@fb.com

tools/bpftool: Generalize BPF skeleton support and generate vmlinux.h

2020-06-23T00:01:48+00:00

Adapt Makefile to support BPF skeleton generation beyond single profiler.bpf.c
case. Also add vmlinux.h generation and switch profiler.bpf.c to use it.

clang-bpf-global-var feature is extended and renamed to clang-bpf-co-re to
check for support of preserve_access_index attribute, which, together with BTF
for global variables, is the minimum requirement for modern BPF programs.

Signed-off-by: Andrii Nakryiko 
Signed-off-by: Alexei Starovoitov 
Reviewed-by: Quentin Monnet 
Link: https://lore.kernel.org/bpf/20200619231703.738941-7-andriin@fb.com

tools/bpftool: Minimize bootstrap bpftool

2020-06-23T00:01:48+00:00

Build minimal "bootstrap mode" bpftool to enable skeleton (and, later,
vmlinux.h generation), instead of building almost complete, but slightly
different (w/o skeletons, etc) bpftool to bootstrap complete bpftool build.

Current approach doesn't scale well (engineering-wise) when adding more BPF
programs to bpftool and other complicated functionality, as it requires
constant adjusting of the code to work in both bootstrapped mode and normal
mode.

So it's better to build only minimal bpftool version that supports only BPF
skeleton code generation and BTF-to-C conversion. Thankfully, this is quite
easy to accomplish due to internal modularity of bpftool commands. This will
also allow to keep adding new functionality to bpftool in general, without the
need to care about bootstrap mode for those new parts of bpftool.

Signed-off-by: Andrii Nakryiko 
Signed-off-by: Alexei Starovoitov 
Reviewed-by: Quentin Monnet 
Link: https://lore.kernel.org/bpf/20200619231703.738941-6-andriin@fb.com

tools/bpf: Don't use $(COMPILE.c)

2020-06-02T20:02:38+00:00

When using make kselftest TARGETS=bpf, tools/bpf is built with
MAKEFLAGS=rR, which causes $(COMPILE.c) to be undefined, which in turn
causes the build to fail with

  CC       kselftest/bpf/tools/build/bpftool/map_perf_ring.o
/bin/sh: 1: -MMD: not found

Fix by using $(CC) $(CFLAGS) -c instead of $(COMPILE.c).

Signed-off-by: Ilya Leoshkevich 
Signed-off-by: Daniel Borkmann 
Link: https://lore.kernel.org/bpf/20200602175649.2501580-2-iii@linux.ibm.com

tools: bpftool: Make libcap dependency optional

2020-04-29T21:25:11+00:00

The new libcap dependency is not used for an essential feature of
bpftool, and we could imagine building the tool without checks on
CAP_SYS_ADMIN by disabling probing features as an unprivileged users.

Make it so, in order to avoid a hard dependency on libcap, and to ease
packaging/embedding of bpftool.

Signed-off-by: Quentin Monnet 
Signed-off-by: Daniel Borkmann 
Acked-by: John Fastabend 
Link: https://lore.kernel.org/bpf/20200429144506.8999-4-quentin@isovalent.com