selftests: bpf: update .gitignore with missing generated files

Update .gitignore with missing generated files.

Signed-off-by: Shuah Khan <shuahkh@osg.samsung.com>
Signed-off-by: Daniel Borkmann <da

selftests: bpf: update .gitignore with missing generated files

Update .gitignore with missing generated files.

Signed-off-by: Shuah Khan <shuahkh@osg.samsung.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

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bpf: Add test_tag to .gitignore

Signed-off-by: Mickaël Salaün <mic@digikod.net>
Cc: Alexei Starovoitov <ast@fb.com>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Shuah Khan <shuah@kernel.org>
Signe

bpf: Add test_tag to .gitignore

Signed-off-by: Mickaël Salaün <mic@digikod.net>
Cc: Alexei Starovoitov <ast@fb.com>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

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bpf: Add tests for the lpm trie map

The first part of this program runs randomized tests against the
lpm-bpf-map. It implements a "Trivial Longest Prefix Match" (tlpm)
based on simple, linear, singl

bpf: Add tests for the lpm trie map

The first part of this program runs randomized tests against the
lpm-bpf-map. It implements a "Trivial Longest Prefix Match" (tlpm)
based on simple, linear, single linked lists. The implementation
should be pretty straightforward.

Based on tlpm, this inserts randomized data into bpf-lpm-maps and
verifies the trie-based bpf-map implementation behaves the same way
as tlpm.

The second part uses 'real world' IPv4 and IPv6 addresses and tests
the trie with those.

Signed-off-by: David Herrmann <dh.herrmann@gmail.com>
Signed-off-by: Daniel Mack <daniel@zonque.org>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

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bpf: Preserve const register type on const OR alu ops

Occasionally, clang (e.g. version 3.8.1) translates a sum between two
constant operands using a BPF_OR instead of a BPF_ADD. The verifier is
cur

bpf: Preserve const register type on const OR alu ops

Occasionally, clang (e.g. version 3.8.1) translates a sum between two
constant operands using a BPF_OR instead of a BPF_ADD. The verifier is
currently not handling this scenario, and the destination register type
becomes UNKNOWN_VALUE even if it's still storing a constant. As a result,
the destination register cannot be used as argument to a helper function
expecting a ARG_CONST_STACK_*, limiting some use cases.

Modify the verifier to handle this case, and add a few tests to make sure
all combinations are supported, and stack boundaries are still verified
even with BPF_OR.

Signed-off-by: Gianluca Borello <g.borello@gmail.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

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bpf: add initial suite for selftests

Add a start of a test suite for kernel selftests. This moves test_verifier
and test_maps over to tools/testing/selftests/bpf/ along with various
code improvement

bpf: add initial suite for selftests

Add a start of a test suite for kernel selftests. This moves test_verifier
and test_maps over to tools/testing/selftests/bpf/ along with various
code improvements and also adds a script for invoking test_bpf module.
The test suite can simply be run via selftest framework, f.e.:

# cd tools/testing/selftests/bpf/
# make
# make run_tests

Both test_verifier and test_maps were kind of misplaced in samples/bpf/
directory and we were looking into adding them to selftests for a while
now, so it can be picked up by kbuild bot et al and hopefully also get
more exposure and thus new test case additions.

Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

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selftests/bpf: Whitelist test_progs.h from .gitignore

[ Upstream commit 809ed84de8b3f2fd7b1d06efb94bf98fd318a7d7 ]

Somehow test_progs.h was being included by the existing rule:

selftests/bpf: Whitelist test_progs.h from .gitignore

[ Upstream commit 809ed84de8b3f2fd7b1d06efb94bf98fd318a7d7 ]

Somehow test_progs.h was being included by the existing rule:

/test_progs*

This is bad because:

1) test_progs.h is a checked in file
2) grep-like tools like ripgrep[0] respect gitignore and
test_progs.h was being hidden from searches

[0]: https://github.com/BurntSushi/ripgrep

Fixes: 74b5a5968fe8 ("selftests/bpf: Replace test_progs and test_maps w/ general rule")
Signed-off-by: Daniel Xu <dxu@dxuuu.xyz>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/a46f64944bf678bc652410ca6028d3450f4f7f4b.1623880296.git.dxu@dxuuu.xyz
Signed-off-by: Sasha Levin <sashal@kernel.org>

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bpf: selftest: Move sock_fields test into test_progs

This is a mechanical change to
1. move test_sock_fields.c to prog_tests/sock_fields.c
2. rename progs/test_sock_fields_kern.c to

bpf: selftest: Move sock_fields test into test_progs

This is a mechanical change to
1. move test_sock_fields.c to prog_tests/sock_fields.c
2. rename progs/test_sock_fields_kern.c to progs/test_sock_fields.c

Minimal change is made to the code itself. Next patch will make
changes to use new ways of writing test, e.g. use skel and global
variables.

Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200925000427.3857814-1-kafai@fb.com

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selftests/bpf: Merge most of test_btf into test_progs

Merge 183 tests from test_btf into test_progs framework to be exercised
regularly. All the test_btf tests that were moved are modele

selftests/bpf: Merge most of test_btf into test_progs

Merge 183 tests from test_btf into test_progs framework to be exercised
regularly. All the test_btf tests that were moved are modeled as proper
sub-tests in test_progs framework for ease of debugging and reporting.

No functional or behavioral changes were intended, I tried to preserve
original behavior as much as possible. E.g., `test_progs -v` will activate
"always_log" flag to emit BTF validation log.

The only difference is in reducing the max_entries limit for pretty-printing
tests from (128 * 1024) to just 128 to reduce tests running time without
reducing the coverage.

Example test run:

$ sudo ./test_progs -n 8
...
#8 btf:OK
Summary: 1/183 PASSED, 0 SKIPPED, 0 FAILED

Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200916004819.3767489-1-andriin@fb.com

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selftests/bpf: Remove test_align leftovers

Calling generic selftests "make install" fails as rsync expects all
files from TEST_GEN_PROGS to be present. The binary is not generated
an

selftests/bpf: Remove test_align leftovers

Calling generic selftests "make install" fails as rsync expects all
files from TEST_GEN_PROGS to be present. The binary is not generated
anymore (commit 3b09d27cc93d) so we can safely remove it from there
and also from gitignore.

Fixes: 3b09d27cc93d ("selftests/bpf: Move test_align under test_progs")
Signed-off-by: Veronika Kabatova <vkabatov@redhat.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Jesper Dangaard Brouer <brouer@redhat.com>
Link: https://lore.kernel.org/bpf/20200819160710.1345956-1-vkabatov@redhat.com

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selftests/bpf: Add benchmark runner infrastructure

While working on BPF ringbuf implementation, testing, and benchmarking, I've
developed a pretty generic and modular benchmark runner, w

selftests/bpf: Add benchmark runner infrastructure

While working on BPF ringbuf implementation, testing, and benchmarking, I've
developed a pretty generic and modular benchmark runner, which seems to be
generically useful, as I've already used it for one more purpose (testing
fastest way to trigger BPF program, to minimize overhead of in-kernel code).

This patch adds generic part of benchmark runner and sets up Makefile for
extending it with more sets of benchmarks.

Benchmarker itself operates by spinning up specified number of producer and
consumer threads, setting up interval timer sending SIGALARM signal to
application once a second. Every second, current snapshot with hits/drops
counters are collected and stored in an array. Drops are useful for
producer/consumer benchmarks in which producer might overwhelm consumers.

Once test finishes after given amount of warm-up and testing seconds, mean and
stddev are calculated (ignoring warm-up results) and is printed out to stdout.
This setup seems to give consistent and accurate results.

To validate behavior, I added two atomic counting tests: global and local.
For global one, all the producer threads are atomically incrementing same
counter as fast as possible. This, of course, leads to huge drop of
performance once there is more than one producer thread due to CPUs fighting
for the same memory location.

Local counting, on the other hand, maintains one counter per each producer
thread, incremented independently. Once per second, all counters are read and
added together to form final "counting throughput" measurement. As expected,
such setup demonstrates linear scalability with number of producers (as long
as there are enough physical CPU cores, of course). See example output below.
Also, this setup can nicely demonstrate disastrous effects of false sharing,
if care is not taken to take those per-producer counters apart into
independent cache lines.

Demo output shows global counter first with 1 producer, then with 4. Both
total and per-producer performance significantly drop. The last run is local
counter with 4 producers, demonstrating near-perfect scalability.

$ ./bench -a -w1 -d2 -p1 count-global
Setting up benchmark 'count-global'...
Benchmark 'count-global' started.
Iter 0 ( 24.822us): hits 148.179M/s (148.179M/prod), drops 0.000M/s
Iter 1 ( 37.939us): hits 149.308M/s (149.308M/prod), drops 0.000M/s
Iter 2 (-10.774us): hits 150.717M/s (150.717M/prod), drops 0.000M/s
Iter 3 ( 3.807us): hits 151.435M/s (151.435M/prod), drops 0.000M/s
Summary: hits 150.488 ± 1.079M/s (150.488M/prod), drops 0.000 ± 0.000M/s

$ ./bench -a -w1 -d2 -p4 count-global
Setting up benchmark 'count-global'...
Benchmark 'count-global' started.
Iter 0 ( 60.659us): hits 53.910M/s ( 13.477M/prod), drops 0.000M/s
Iter 1 (-17.658us): hits 53.722M/s ( 13.431M/prod), drops 0.000M/s
Iter 2 ( 5.865us): hits 53.495M/s ( 13.374M/prod), drops 0.000M/s
Iter 3 ( 0.104us): hits 53.606M/s ( 13.402M/prod), drops 0.000M/s
Summary: hits 53.608 ± 0.113M/s ( 13.402M/prod), drops 0.000 ± 0.000M/s

$ ./bench -a -w1 -d2 -p4 count-local
Setting up benchmark 'count-local'...
Benchmark 'count-local' started.
Iter 0 ( 23.388us): hits 640.450M/s (160.113M/prod), drops 0.000M/s
Iter 1 ( 2.291us): hits 605.661M/s (151.415M/prod), drops 0.000M/s
Iter 2 ( -6.415us): hits 607.092M/s (151.773M/prod), drops 0.000M/s
Iter 3 ( -1.361us): hits 601.796M/s (150.449M/prod), drops 0.000M/s
Summary: hits 604.849 ± 2.739M/s (151.212M/prod), drops 0.000 ± 0.000M/s

Benchmark runner supports setting thread affinity for producer and consumer
threads. You can use -a flag for default CPU selection scheme, where first
consumer gets CPU #0, next one gets CPU #1, and so on. Then producer threads
pick up next CPU and increment one-by-one as well. But user can also specify
a set of CPUs independently for producers and consumers with --prod-affinity
1,2-10,15 and --cons-affinity <set-of-cpus>. The latter allows to force
producers and consumers to share same set of CPUs, if necessary.

Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20200512192445.2351848-3-andriin@fb.com

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selftests/bpf: Add runqslower binary to .gitignore

With recent changes, runqslower is being copied into selftests/bpf root
directory. So add it into .gitignore.

Fixes: b26d1e2b6

selftests/bpf: Add runqslower binary to .gitignore

With recent changes, runqslower is being copied into selftests/bpf root
directory. So add it into .gitignore.

Fixes: b26d1e2b6028 ("selftests/bpf: Copy runqslower to OUTPUT directory")
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Cc: Veronika Kabatova <vkabatov@redhat.com>
Link: https://lore.kernel.org/bpf/20200429012111.277390-12-andriin@fb.com

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selftests/bpf: Convert test_hashmap into test_progs test

Fold stand-alone test_hashmap test into test_progs.

Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexe

selftests/bpf: Convert test_hashmap into test_progs test

Fold stand-alone test_hashmap test into test_progs.

Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200429012111.277390-4-andriin@fb.com

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Merge tag 'spdx-5.7-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/spdx

Pull SPDX updates from Greg KH:
"Here are three SPDX patches for 5.7-rc1.

One fixes up t

Merge tag 'spdx-5.7-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/spdx

Pull SPDX updates from Greg KH:
"Here are three SPDX patches for 5.7-rc1.

One fixes up the SPDX tag for a single driver, while the other two go
through the tree and add SPDX tags for all of the .gitignore files as
needed.

Nothing too complex, but you will get a merge conflict with your
current tree, that should be trivial to handle (one file modified by
two things, one file deleted.)

All three of these have been in linux-next for a while, with no
reported issues other than the merge conflict"

* tag 'spdx-5.7-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/spdx:
ASoC: MT6660: make spdxcheck.py happy
.gitignore: add SPDX License Identifier
.gitignore: remove too obvious comments

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.gitignore: add SPDX License Identifier

Add SPDX License Identifier to all .gitignore files.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Signed-off-by: Greg Kroah-Hart

.gitignore: add SPDX License Identifier

Add SPDX License Identifier to all .gitignore files.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

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tools/testing/selftests/bpf: Add self-tests for new helper bpf_get_ns_current_pid_tgid.

Self tests added for new helper bpf_get_ns_current_pid_tgid

Signed-off-by: Carlos Neira <cnei

tools/testing/selftests/bpf: Add self-tests for new helper bpf_get_ns_current_pid_tgid.

Self tests added for new helper bpf_get_ns_current_pid_tgid

Signed-off-by: Carlos Neira <cneirabustos@gmail.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200304204157.58695-4-cneirabustos@gmail.com

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selftests: Refactor build to remove tools/lib/bpf from include path

To make sure no new files are introduced that doesn't include the bpf/
prefix in its #include, remove tools/lib/bpf fr

selftests: Refactor build to remove tools/lib/bpf from include path

To make sure no new files are introduced that doesn't include the bpf/
prefix in its #include, remove tools/lib/bpf from the include path
entirely.

Instead, we introduce a new header files directory under the scratch tools/
dir, and add a rule to run the 'install_headers' rule from libbpf to have a
full set of consistent libbpf headers in $(OUTPUT)/tools/include/bpf, and
then use $(OUTPUT)/tools/include as the include path for selftests.

For consistency we also make sure we put all the scratch build files from
other bpftool and libbpf into tools/build/, so everything stays within
selftests/.

Signed-off-by: Toke Høiland-Jørgensen <toke@redhat.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/157952561246.1683545.2762245552022369203.stgit@toke.dk

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selftests/bpf: Further clean up Makefile output

Further clean up Makefile output:
- hide "entering directory" messages;
- silvence sub-Make command echoing;
- succinct MKDIR mess

selftests/bpf: Further clean up Makefile output

Further clean up Makefile output:
- hide "entering directory" messages;
- silvence sub-Make command echoing;
- succinct MKDIR messages.

Also remove few test binaries that are not produced anymore from .gitignore.

Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200110051716.1591485-4-andriin@fb.com

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

Simple overlapping changes in bpf land wrt. bpf_helper_defs.h
handling.

Signed-off-by: David S. Miller <davem@dave

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

Simple overlapping changes in bpf land wrt. bpf_helper_defs.h
handling.

Signed-off-by: David S. Miller <davem@davemloft.net>

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libbpf: Fix build on read-only filesystems

I got the following error when I tried to build perf on a read-only
filesystem with O=dir option.

$ cd /some/where/ro/linux/tools/pe

libbpf: Fix build on read-only filesystems

I got the following error when I tried to build perf on a read-only
filesystem with O=dir option.

$ cd /some/where/ro/linux/tools/perf
$ make O=$HOME/build/perf
...
CC /home/namhyung/build/perf/lib.o
/bin/sh: bpf_helper_defs.h: Read-only file system
make[3]: *** [Makefile:184: bpf_helper_defs.h] Error 1
make[2]: *** [Makefile.perf:778: /home/namhyung/build/perf/libbpf.a] Error 2
make[2]: *** Waiting for unfinished jobs....
LD /home/namhyung/build/perf/libperf-in.o
AR /home/namhyung/build/perf/libperf.a
PERF_VERSION = 5.4.0
make[1]: *** [Makefile.perf:225: sub-make] Error 2
make: *** [Makefile:70: all] Error 2

It was becaused bpf_helper_defs.h was generated in current directory.
Move it to OUTPUT directory.

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Tested-by: Andrii Nakryiko <andriin@fb.com>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Link: https://lore.kernel.org/bpf/20191223061326.843366-1-namhyung@kernel.org

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selftests/bpf: Convert test_cgroup_attach to prog_tests

Convert test_cgroup_attach to prog_tests.

This change does a lot of things but in many cases it's pretty expensive
to sep

selftests/bpf: Convert test_cgroup_attach to prog_tests

Convert test_cgroup_attach to prog_tests.

This change does a lot of things but in many cases it's pretty expensive
to separate them, so they go in one commit. Nevertheless the logic is
ketp as is and changes made are just moving things around, simplifying
them (w/o changing the meaning of the tests) and making prog_tests
compatible:

* split the 3 tests in the file into 3 separate files in prog_tests/;

* rename the test functions to test_<file_base_name>;

* remove unused includes, constants, variables and functions from every
test;

* replace `if`-s with or `if (CHECK())` where additional context should
be logged and with `if (CHECK_FAIL())` where line number is enough;

* switch from `log_err()` to logging via `CHECK()`;

* replace `assert`-s with `CHECK_FAIL()` to avoid crashing the whole
test_progs if one assertion fails;

* replace cgroup_helpers with test__join_cgroup() in
cgroup_attach_override only, other tests need more fine-grained
control for cgroup creation/deletion so cgroup_helpers are still used
there;

* simplify cgroup_attach_autodetach by switching to easiest possible
program since this test doesn't really need such a complicated program
as cgroup_attach_multi does;

* remove test_cgroup_attach.c itself.

Signed-off-by: Andrey Ignatov <rdna@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Link: https://lore.kernel.org/bpf/0ff19cc64d2dc5cf404349f07131119480e10e32.1576741281.git.rdna@fb.com

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selftests/bpf: Add BPF skeletons selftests and convert attach_probe.c

Add BPF skeleton generation to selftest/bpf's Makefile. Convert attach_probe.c
to use skeleton.

Signed-off-

selftests/bpf: Add BPF skeletons selftests and convert attach_probe.c

Add BPF skeleton generation to selftest/bpf's Makefile. Convert attach_probe.c
to use skeleton.

Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Link: https://lore.kernel.org/bpf/20191214014341.3442258-15-andriin@fb.com

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selftests/bpf: Bring back c++ include/link test

Commit 5c26f9a78358 ("libbpf: Don't use cxx to test_libpf target")
converted existing c++ test to c. We still want to include and
link

selftests/bpf: Bring back c++ include/link test

Commit 5c26f9a78358 ("libbpf: Don't use cxx to test_libpf target")
converted existing c++ test to c. We still want to include and
link against libbpf from c++ code, so reinstate this test back,
this time in a form of a selftest with a clear comment about
its purpose.

v2:
* -lelf -> $(LDLIBS) (Andrii Nakryiko)

Fixes: 5c26f9a78358 ("libbpf: Don't use cxx to test_libpf target")
Signed-off-by: Stanislav Fomichev <sdf@google.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Link: https://lore.kernel.org/bpf/20191202215931.248178-1-sdf@google.com

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selftests/bpf: Fix .gitignore to ignore no_alu32/

When switching to alu32 by default, no_alu32/ subdirectory wasn't added
to .gitignore. Fix it.

Fixes: e13a2fe642bd ("tools/bpf:

selftests/bpf: Fix .gitignore to ignore no_alu32/

When switching to alu32 by default, no_alu32/ subdirectory wasn't added
to .gitignore. Fix it.

Fixes: e13a2fe642bd ("tools/bpf: Turn on llvm alu32 attribute by default")
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20191025045503.3043427-1-andriin@fb.com

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selftest/bpf: Remove test_libbpf.sh and test_libbpf_open

test_progs is much more sophisticated superset of tests compared to
test_libbpf.sh and test_libbpf_open. Remove test_libbpf.sh an

selftest/bpf: Remove test_libbpf.sh and test_libbpf_open

test_progs is much more sophisticated superset of tests compared to
test_libbpf.sh and test_libbpf_open. Remove test_libbpf.sh and
test_libbpf_open.

Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20191016060051.2024182-8-andriin@fb.com

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selftests/bpf: Replace test_progs and test_maps w/ general rule

Define test runner generation meta-rule that codifies dependencies
between test runner, its tests, and its dependent BPF p

selftests/bpf: Replace test_progs and test_maps w/ general rule

Define test runner generation meta-rule that codifies dependencies
between test runner, its tests, and its dependent BPF programs. Use that
for defining test_progs and test_maps test-runners. Also additionally define
2 flavors of test_progs:
- alu32, which builds BPF programs with 32-bit registers codegen;
- bpf_gcc, which build BPF programs using GCC, if it supports BPF target.

Overall, this is accomplished through $(eval)'ing a set of generic
rules, which defines Makefile targets dynamically at runtime. See
comments explaining the need for 2 $(evals), though.

For each test runner we have (test_maps and test_progs, currently), and,
optionally, their flavors, the logic of build process is modeled as
follows (using test_progs as an example):
- all BPF objects are in progs/:
- BPF object's .o file is built into output directory from
corresponding progs/.c file;
- all BPF objects in progs/*.c depend on all progs/*.h headers;
- all BPF objects depend on bpf_*.h helpers from libbpf (but not
libbpf archive). There is an extra rule to trigger bpf_helper_defs.h
(re-)build, if it's not present/outdated);
- build recipe for BPF object can be re-defined per test runner/flavor;
- test files are built from prog_tests/*.c:
- all such test file objects are built on individual file basis;
- currently, every single test file depends on all BPF object files;
this might be improved in follow up patches to do 1-to-1 dependency,
but allowing to customize this per each individual test;
- each test runner definition can specify a list of extra .c and .h
files to be built along test files and test runner binary; all such
headers are becoming automatic dependency of each test .c file;
- due to test files sometimes embedding (using .incbin assembly
directive) contents of some BPF objects at compilation time, which are
expected to be in CWD of compiler, compilation for test file object does
cd into test runner's output directory; to support this mode all the
include paths are turned into absolute paths using $(abspath) make
function;
- prog_tests/test.h is automatically (re-)generated with an entry for
each .c file in prog_tests/;
- final test runner binary is linked together from test object files and
extra object files, linking together libbpf's archive as well;
- it's possible to specify extra "resource" files/targets, which will be
copied into test runner output directory, if it differes from
Makefile-wide $(OUTPUT). This is used to ensure btf_dump test cases and
urandom_read binary is put into a test runner's CWD for tests to find
them in runtime.

For flavored test runners, their output directory is a subdirectory of
common Makefile-wide $(OUTPUT) directory with flavor name used as
subdirectory name.

BPF objects targets might be reused between different test runners, so
extra checks are employed to not double-define them. Similarly, we have
redefinition guards for output directories and test headers.

test_verifier follows slightly different patterns and is simple enough
to not justify generalizing TEST_RUNNER_DEFINE/TEST_RUNNER_DEFINE_RULES
further to accomodate these differences. Instead, rules for
test_verifier are minimized and simplified, while preserving correctness
of dependencies.

Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20191016060051.2024182-6-andriin@fb.com

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