Commit Graph

1043064 Commits

Author SHA1 Message Date
Johan Almbladh
68813605de bpf/tests: Add test of ALU shifts with operand register aliasing
This patch adds a tests of ALU32 and ALU64 LSH/RSH/ARSH operations for the
case when the two operands are the same register. Mainly intended to test
JITs that implement ALU64 shifts with 32-bit CPU instructions.

Also renamed related helper functions for consistency with the new tests.

Signed-off-by: Johan Almbladh <johan.almbladh@anyfinetworks.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20211001130348.3670534-10-johan.almbladh@anyfinetworks.com
2021-10-01 17:04:26 +02:00
Johan Almbladh
6fae2e8a1d bpf/tests: Add exhaustive tests of BPF_ATOMIC register combinations
This patch adds tests of all register combinations for BPF_ATOMIC
operations on both BPF_W and BPF_DW sizes.

Signed-off-by: Johan Almbladh <johan.almbladh@anyfinetworks.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20211001130348.3670534-9-johan.almbladh@anyfinetworks.com
2021-10-01 17:04:26 +02:00
Johan Almbladh
daed6083f4 bpf/tests: Add exhaustive tests of ALU register combinations
This patch replaces the current register combination test with new
exhaustive tests. Before, only a subset of register combinations was
tested for ALU64 DIV. Now, all combinatons of operand registers are
tested, including the case when they are the same, and for all ALU32
and ALU64 operations.

Signed-off-by: Johan Almbladh <johan.almbladh@anyfinetworks.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20211001130348.3670534-8-johan.almbladh@anyfinetworks.com
2021-10-01 17:04:26 +02:00
Johan Almbladh
e42fc3c2c4 bpf/tests: Minor restructuring of ALU tests
This patch moves the ALU LSH/RSH/ARSH reference computations into the
common reference value function. Also fix typo in constants so they
now have the intended values.

Signed-off-by: Johan Almbladh <johan.almbladh@anyfinetworks.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20211001130348.3670534-7-johan.almbladh@anyfinetworks.com
2021-10-01 17:04:26 +02:00
Johan Almbladh
e2f9797b3c bpf/tests: Add more tests for ALU and ATOMIC register clobbering
This patch expands the register-clobbering-during-function-call tests
to cover more all ALU32/64 MUL, DIV and MOD operations and all ATOMIC
operations. In short, if a JIT implements a complex operation with
a call to an external function, it must make sure to save and restore
all its caller-saved registers that may be clobbered by the call.

Signed-off-by: Johan Almbladh <johan.almbladh@anyfinetworks.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20211001130348.3670534-6-johan.almbladh@anyfinetworks.com
2021-10-01 17:04:26 +02:00
Johan Almbladh
0bbaa02b48 bpf/tests: Add tests to check source register zero-extension
This patch adds tests to check that the source register is preserved when
zero-extending a 32-bit value. In particular, it checks that the source
operand is not zero-extended in-place.

Signed-off-by: Johan Almbladh <johan.almbladh@anyfinetworks.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20211001130348.3670534-5-johan.almbladh@anyfinetworks.com
2021-10-01 17:04:26 +02:00
Johan Almbladh
f68e8efd7f bpf/tests: Add exhaustive tests of BPF_ATOMIC magnitudes
This patch adds a series of test to verify the operation of BPF_ATOMIC
with BPF_DW and BPF_W sizes, for all power-of-two magnitudes of the
register value operand.

Also fixes a confusing typo in the comment for a related test.

Signed-off-by: Johan Almbladh <johan.almbladh@anyfinetworks.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20211001130348.3670534-4-johan.almbladh@anyfinetworks.com
2021-10-01 17:04:25 +02:00
Johan Almbladh
89b6346276 bpf/tests: Add zero-extension checks in BPF_ATOMIC tests
This patch updates the existing tests of BPF_ATOMIC operations to verify
that a 32-bit register operand is properly zero-extended. In particular,
it checks the operation on archs that require 32-bit operands to be
properly zero-/sign-extended or the result is undefined, e.g. MIPS64.

Signed-off-by: Johan Almbladh <johan.almbladh@anyfinetworks.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20211001130348.3670534-3-johan.almbladh@anyfinetworks.com
2021-10-01 17:04:25 +02:00
Johan Almbladh
caaaa1667b bpf/tests: Add tests of BPF_LDX and BPF_STX with small sizes
This patch adds a series of tests to verify the behavior of BPF_LDX and
BPF_STX with BPF_B//W sizes in isolation. In particular, it checks that
BPF_LDX zero-extendeds the result, and that BPF_STX does not overwrite
adjacent bytes in memory.

BPF_ST and operations on BPF_DW size are deemed to be sufficiently
tested by existing tests.

Signed-off-by: Johan Almbladh <johan.almbladh@anyfinetworks.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20211001130348.3670534-2-johan.almbladh@anyfinetworks.com
2021-10-01 17:04:25 +02:00
Kev Jackson
6bbc710373 bpf, xdp, docs: Correct some English grammar and spelling
Header DOC on include/net/xdp.h contained a few English grammer and
spelling errors.

Signed-off-by: Kev Jackson <foamdino@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Jesper Dangaard Brouer <brouer@redhat.com>
Link: https://lore.kernel.org/bpf/YVVaWmKqA8l9Tm4J@kev-VirtualBox
2021-09-30 23:23:49 +02:00
Po-Hsu Lin
d4b6f87e8d selftests/bpf: Use kselftest skip code for skipped tests
There are several test cases in the bpf directory are still using
exit 0 when they need to be skipped. Use kselftest framework skip
code instead so it can help us to distinguish the return status.

Criterion to filter out what should be fixed in bpf directory:
  grep -r "exit 0" -B1 | grep -i skip

This change might cause some false-positives if people are running
these test scripts directly and only checking their return codes,
which will change from 0 to 4. However I think the impact should be
small as most of our scripts here are already using this skip code.
And there will be no such issue if running them with the kselftest
framework.

Signed-off-by: Po-Hsu Lin <po-hsu.lin@canonical.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20210929051250.13831-1-po-hsu.lin@canonical.com
2021-09-30 23:09:17 +02:00
Kumar Kartikeya Dwivedi
e68ac00827 libbpf: Fix skel_internal.h to set errno on loader retval < 0
When the loader indicates an internal error (result of a checked bpf
system call), it returns the result in attr.test.retval. However, tests
that rely on ASSERT_OK_PTR on NULL (returned from light skeleton) may
miss that NULL denotes an error if errno is set to 0. This would result
in skel pointer being NULL, while ASSERT_OK_PTR returning 1, leading to
a SEGV on dereference of skel, because libbpf_get_error relies on the
assumption that errno is always set in case of error for ptr == NULL.

In particular, this was observed for the ksyms_module test. When
executed using `./test_progs -t ksyms`, prior tests manipulated errno
and the test didn't crash when it failed at ksyms_module load, while
using `./test_progs -t ksyms_module` crashed due to errno being
untouched.

Fixes: 6723474373 (libbpf: Generate loader program out of BPF ELF file.)
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20210927145941.1383001-11-memxor@gmail.com
2021-09-29 20:42:32 -07:00
Toke Høiland-Jørgensen
161ecd5379 libbpf: Properly ignore STT_SECTION symbols in legacy map definitions
The previous patch to ignore STT_SECTION symbols only added the ignore
condition in one of them. This fails if there's more than one map
definition in the 'maps' section, because the subsequent modulus check will
fail, resulting in error messages like:

libbpf: elf: unable to determine legacy map definition size in ./xdpdump_xdp.o

Fix this by also ignoring STT_SECTION in the first loop.

Fixes: c3e8c44a90 ("libbpf: Ignore STT_SECTION symbols in 'maps' section")
Signed-off-by: Toke Høiland-Jørgensen <toke@redhat.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20210929213837.832449-1-toke@redhat.com
2021-09-29 15:50:32 -07:00
Lorenz Bauer
de21d8bf77 bpf: Do not invoke the XDP dispatcher for PROG_RUN with single repeat
We have a unit test that invokes an XDP program with 1m different
inputs, aka 1m BPF_PROG_RUN syscalls. We run this test concurrently
with slight variations in how we generated the input.

Since commit f23c4b3924 ("bpf: Start using the BPF dispatcher in BPF_TEST_RUN")
the unit test has slowed down significantly. Digging deeper reveals that
the concurrent tests are serialised in the kernel on the XDP dispatcher.
This is a global resource that is protected by a mutex, on which we contend.

Fix this by not calling into the XDP dispatcher if we only want to perform
a single run of the BPF program.

See: https://lore.kernel.org/bpf/CACAyw9_y4QumOW35qpgTbLsJ532uGq-kVW-VESJzGyiZkypnvw@mail.gmail.com/

Signed-off-by: Lorenz Bauer <lmb@cloudflare.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20210928093100.27124-1-lmb@cloudflare.com
2021-09-29 14:10:05 -07:00
Alexei Starovoitov
66fe332417 libbpf: Make gen_loader data aligned.
Align gen_loader data to 8 byte boundary to make sure union bpf_attr,
bpf_insns and other structs are aligned.

Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20210927145941.1383001-9-memxor@gmail.com
2021-09-29 13:27:19 -07:00
Kumar Kartikeya Dwivedi
e31eec77e4 bpf: selftests: Fix fd cleanup in get_branch_snapshot
Cleanup code uses while (cpu++ < cpu_cnt) for closing fds, which means
it starts iterating from 1 for closing fds. If the first fd is -1, it
skips over it and closes garbage fds (typically zero) in the remaining
array. This leads to test failures for future tests when they end up
storing fd 0 (as the slot becomes free due to close(0)) in ldimm64's BTF
fd, ending up trying to match module BTF id with vmlinux.

This was observed as spurious CI failure for the ksym_module_libbpf and
module_attach tests. The test ends up closing fd 0 and breaking libbpf's
assumption that module BTF fd will always be > 0, which leads to the
kernel thinking that we are pointing to a BTF ID in vmlinux BTF.

Fixes: 025bd7c753 (selftests/bpf: Add test for bpf_get_branch_snapshot)
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Song Liu <songliubraving@fb.com>
Link: https://lore.kernel.org/bpf/20210927145941.1383001-12-memxor@gmail.com
2021-09-29 13:25:09 -07:00
Magnus Karlsson
3103836496 xsk: Fix clang build error in __xp_alloc
Fix a build error with clang in __xp_alloc():

  [...]
  net/xdp/xsk_buff_pool.c:465:15: error: variable 'xskb' is uninitialized
  when used here [-Werror,-Wuninitialized]
                          xp_release(xskb);
                                     ^~~~

This is correctly detected by clang, but not gcc. In fact, the xp_release()
statement should not be there at all in the refactored code, just remove it.

Fixes: 94033cd8e7 ("xsk: Optimize for aligned case")
Reported-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Magnus Karlsson <magnus.karlsson@intel.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Maciej Fijalkowski <maciej.fijalkowski@intel.com>
Link: https://lore.kernel.org/bpf/20210929061403.8587-1-magnus.karlsson@gmail.com
2021-09-29 13:59:13 +02:00
Yonghong Song
38261f369f selftests/bpf: Fix probe_user test failure with clang build kernel
clang build kernel failed the selftest probe_user.
  $ ./test_progs -t probe_user
  $ ...
  $ test_probe_user:PASS:get_kprobe_res 0 nsec
  $ test_probe_user:FAIL:check_kprobe_res wrong kprobe res from probe read: 0.0.0.0:0
  $ #94 probe_user:FAIL

The test attached to kernel function __sys_connect(). In net/socket.c, we have
  int __sys_connect(int fd, struct sockaddr __user *uservaddr, int addrlen)
  {
        ......
  }
  ...
  SYSCALL_DEFINE3(connect, int, fd, struct sockaddr __user *, uservaddr,
                  int, addrlen)
  {
        return __sys_connect(fd, uservaddr, addrlen);
  }

The gcc compiler (8.5.0) does not inline __sys_connect() in syscall entry
function. But latest clang trunk did the inlining. So the bpf program
is not triggered.

To make the test more reliable, let us kprobe the syscall entry function
instead. Note that x86_64, arm64 and s390 have syscall wrappers and they have
to be handled specially.

Signed-off-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20210929033000.3711921-1-yhs@fb.com
2021-09-28 23:17:22 -07:00
Alexei Starovoitov
72e1781a5d Merge branch 'bpf: Build with -Wcast-function-type'
Kees Cook says:

====================

Hi,

In order to keep ahead of cases in the kernel where Control Flow Integrity
(CFI) may trip over function call casts, enabling -Wcast-function-type
is helpful. To that end, replace BPF_CAST_CALL() as it triggers warnings
with this option and is now one of the last places in the kernel in need
of fixing.

Thanks,

-Kees

v2:
- rebase to bpf-next
- add acks
v1: https://lore.kernel.org/lkml/20210927182700.2980499-1-keescook@chromium.org
====================

Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2021-09-28 16:27:19 -07:00
Kees Cook
102acbacfd bpf: Replace callers of BPF_CAST_CALL with proper function typedef
In order to keep ahead of cases in the kernel where Control Flow
Integrity (CFI) may trip over function call casts, enabling
-Wcast-function-type is helpful. To that end, BPF_CAST_CALL causes
various warnings and is one of the last places in the kernel
triggering this warning.

For actual function calls, replace BPF_CAST_CALL() with a typedef, which
captures the same details about the given function pointers.

This change results in no object code difference.

Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Link: https://github.com/KSPP/linux/issues/20
Link: https://lore.kernel.org/lkml/CAEf4Bzb46=-J5Fxc3mMZ8JQPtK1uoE0q6+g6WPz53Cvx=CBEhw@mail.gmail.com
Link: https://lore.kernel.org/bpf/20210928230946.4062144-3-keescook@chromium.org
2021-09-28 16:27:18 -07:00
Kees Cook
3d717fad50 bpf: Replace "want address" users of BPF_CAST_CALL with BPF_CALL_IMM
In order to keep ahead of cases in the kernel where Control Flow
Integrity (CFI) may trip over function call casts, enabling
-Wcast-function-type is helpful. To that end, BPF_CAST_CALL causes
various warnings and is one of the last places in the kernel triggering
this warning.

Most places using BPF_CAST_CALL actually just want a void * to perform
math on. It's not actually performing a call, so just use a different
helper to get the void *, by way of the new BPF_CALL_IMM() helper, which
can clean up a common copy/paste idiom as well.

This change results in no object code difference.

Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Reviewed-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://github.com/KSPP/linux/issues/20
Link: https://lore.kernel.org/lkml/CAEf4Bzb46=-J5Fxc3mMZ8JQPtK1uoE0q6+g6WPz53Cvx=CBEhw@mail.gmail.com
Link: https://lore.kernel.org/bpf/20210928230946.4062144-2-keescook@chromium.org
2021-09-28 16:27:18 -07:00
Yucong Sun
09710d82c0 bpftool: Avoid using "?: " in generated code
"?:" is a GNU C extension, some environment has warning flags for its
use, or even prohibit it directly.  This patch avoid triggering these
problems by simply expand it to its full form, no functionality change.

Signed-off-by: Yucong Sun <fallentree@fb.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20210928184221.1545079-1-fallentree@fb.com
2021-09-28 15:19:22 -07:00
Alexei Starovoitov
4e874b119c Merge branch 'libbpf: stricter BPF program section name handling'
Andrii Nakryiko says:

====================

Implement opt-in stricter BPF program section name (SEC()) handling logic. For
a lot of supported ELF section names, enforce exact section name match with no
arbitrary characters added at the end. See patch #9 for more details.

To allow this, patches #2 through #4 clean up and preventively fix selftests,
normalizing existing SEC() usage across multiple selftests. While at it, those
patches also reduce the amount of remaining bpf_object__find_program_by_title()
uses, which should be completely removed soon, given it's an API with
ambiguous semantics and will be deprecated and eventually removed in libbpf 1.0.

Patch #1 also introduces SEC("tc") as an alias for SEC("classifier"). "tc" is
a better and less misleading name, so patch #3 replaces all classifier* uses
with nice and short SEC("tc").

Last patch is also fixing "sk_lookup/" definition to not require and not allow
extra "/blah" parts after it, which serve no meaning.

All the other patches are gradual internal libbpf changes to:
  - allow this optional strict logic for ELF section name handling;
  - allow new use case (for now for "struct_ops", but that could be extended
    to, say, freplace definitions), in which it can be used stand-alone to
    specify just type (SEC("struct_ops")), or also accept extra parameters
    which can be utilized by libbpf to either get more data or double-check
    valid use (e.g., SEC("struct_ops/dctcp_init") to specify desired
    struct_ops operation that is supposed to be implemented);
  - get libbpf's internal logic ready to allow other libraries and
    applications to specify their custom handlers for ELF section name for BPF
    programs. All the pieces are in place, the only thing preventing making
    this as public libbpf API is reliance on internal type for specifying BPF
    program load attributes. The work is planned to revamp related low-level
    libbpf APIs, at which point it will be possible to just re-use such new
    types for coordination between libbpf and custom handlers.

These changes are a part of libbpf 1.0 effort ([0]). They are also intended to
be applied on top of the previous preparatory series [1], so currently CI will
be failing to apply them to bpf-next until that patch set is landed. Once it
is landed, kernel-patches daemon will automatically retest this patch set.

  [0] https://github.com/libbpf/libbpf/wiki/Libbpf:-the-road-to-v1.0#stricter-and-more-uniform-bpf-program-section-name-sec-handling
  [1] https://patchwork.kernel.org/project/netdevbpf/list/?series=547675&state=*

v3->v4:
  - replace SEC("classifier*") with SEC("tc") (Daniel);
v2->v3:
  - applied acks, addressed most feedback, added comments to new flags (Dave);
v1->v2:
  - rebase onto latest bpf-next and resolve merge conflicts w/ Dave's changes.
====================

Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2021-09-28 13:51:20 -07:00
Andrii Nakryiko
7c80c87ad5 selftests/bpf: Switch sk_lookup selftests to strict SEC("sk_lookup") use
Update "sk_lookup/" definition to be a stand-alone type specifier,
with backwards-compatible prefix match logic in non-libbpf-1.0 mode.

Currently in selftests all the "sk_lookup/<whatever>" uses just use
<whatever> for duplicated unique name encoding, which is redundant as
BPF program's name (C function name) uniquely and descriptively
identifies the intended use for such BPF programs.

With libbpf's SEC_DEF("sk_lookup") definition updated, switch existing
sk_lookup programs to use "unqualified" SEC("sk_lookup") section names,
with no random text after it.

Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Dave Marchevsky <davemarchevsky@fb.com>
Link: https://lore.kernel.org/bpf/20210928161946.2512801-11-andrii@kernel.org
2021-09-28 13:51:20 -07:00
Andrii Nakryiko
dd94d45cf0 libbpf: Add opt-in strict BPF program section name handling logic
Implement strict ELF section name handling for BPF programs. It utilizes
`libbpf_set_strict_mode()` framework and adds new flag: LIBBPF_STRICT_SEC_NAME.

If this flag is set, libbpf will enforce exact section name matching for
a lot of program types that previously allowed just partial prefix
match. E.g., if previously SEC("xdp_whatever_i_want") was allowed, now
in strict mode only SEC("xdp") will be accepted, which makes SEC("")
definitions cleaner and more structured. SEC() now won't be used as yet
another way to uniquely encode BPF program identifier (for that
C function name is better and is guaranteed to be unique within
bpf_object). Now SEC() is strictly BPF program type and, depending on
program type, extra load/attach parameter specification.

Libbpf completely supports multiple BPF programs in the same ELF
section, so multiple BPF programs of the same type/specification easily
co-exist together within the same bpf_object scope.

Additionally, a new (for now internal) convention is introduced: section
name that can be a stand-alone exact BPF program type specificator, but
also could have extra parameters after '/' delimiter. An example of such
section is "struct_ops", which can be specified by itself, but also
allows to specify the intended operation to be attached to, e.g.,
"struct_ops/dctcp_init". Note, that "struct_ops_some_op" is not allowed.
Such section definition is specified as "struct_ops+".

This change is part of libbpf 1.0 effort ([0], [1]).

  [0] Closes: https://github.com/libbpf/libbpf/issues/271
  [1] https://github.com/libbpf/libbpf/wiki/Libbpf:-the-road-to-v1.0#stricter-and-more-uniform-bpf-program-section-name-sec-handling

Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Dave Marchevsky <davemarchevsky@fb.com>
Link: https://lore.kernel.org/bpf/20210928161946.2512801-10-andrii@kernel.org
2021-09-28 13:51:19 -07:00
Andrii Nakryiko
d41ea045a6 libbpf: Complete SEC() table unification for BPF_APROG_SEC/BPF_EAPROG_SEC
Complete SEC() table refactoring towards unified form by rewriting
BPF_APROG_SEC and BPF_EAPROG_SEC definitions with
SEC_DEF(SEC_ATTACHABLE_OPT) (for optional expected_attach_type) and
SEC_DEF(SEC_ATTACHABLE) (mandatory expected_attach_type), respectively.
Drop BPF_APROG_SEC, BPF_EAPROG_SEC, and BPF_PROG_SEC_IMPL macros after
that, leaving SEC_DEF() macro as the only one used.

Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Dave Marchevsky <davemarchevsky@fb.com>
Link: https://lore.kernel.org/bpf/20210928161946.2512801-9-andrii@kernel.org
2021-09-28 13:51:19 -07:00
Andrii Nakryiko
15ea31fadd libbpf: Refactor ELF section handler definitions
Refactor ELF section handler definitions table to use a set of flags and
unified SEC_DEF() macro. This allows for more succinct and table-like
set of definitions, and allows to more easily extend the logic without
adding more verbosity (this is utilized in later patches in the series).

This approach is also making libbpf-internal program pre-load callback
not rely on bpf_sec_def definition, which demonstrates that future
pluggable ELF section handlers will be able to achieve similar level of
integration without libbpf having to expose extra types and APIs.

For starters, update SEC_DEF() definitions and make them more succinct.
Also convert BPF_PROG_SEC() and BPF_APROG_COMPAT() definitions to
a common SEC_DEF() use.

Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Dave Marchevsky <davemarchevsky@fb.com>
Link: https://lore.kernel.org/bpf/20210928161946.2512801-8-andrii@kernel.org
2021-09-28 13:51:19 -07:00
Andrii Nakryiko
13d35a0cf1 libbpf: Reduce reliance of attach_fns on sec_def internals
Move closer to not relying on bpf_sec_def internals that won't be part
of public API, when pluggable SEC() handlers will be allowed. Drop
pre-calculated prefix length, and in various helpers don't rely on this
prefix length availability. Also minimize reliance on knowing
bpf_sec_def's prefix for few places where section prefix shortcuts are
supported (e.g., tp vs tracepoint, raw_tp vs raw_tracepoint).

Given checking some string for having a given string-constant prefix is
such a common operation and so annoying to be done with pure C code, add
a small macro helper, str_has_pfx(), and reuse it throughout libbpf.c
where prefix comparison is performed. With __builtin_constant_p() it's
possible to have a convenient helper that checks some string for having
a given prefix, where prefix is either string literal (or compile-time
known string due to compiler optimization) or just a runtime string
pointer, which is quite convenient and saves a lot of typing and string
literal duplication.

Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Dave Marchevsky <davemarchevsky@fb.com>
Link: https://lore.kernel.org/bpf/20210928161946.2512801-7-andrii@kernel.org
2021-09-28 13:51:19 -07:00
Andrii Nakryiko
12d9466d8b libbpf: Refactor internal sec_def handling to enable pluggability
Refactor internals of libbpf to allow adding custom SEC() handling logic
easily from outside of libbpf. To that effect, each SEC()-handling
registration sets mandatory program type/expected attach type for
a given prefix and can provide three callbacks called at different
points of BPF program lifetime:

  - init callback for right after bpf_program is initialized and
  prog_type/expected_attach_type is set. This happens during
  bpf_object__open() step, close to the very end of constructing
  bpf_object, so all the libbpf APIs for querying and updating
  bpf_program properties should be available;

  - pre-load callback is called right before BPF_PROG_LOAD command is
  called in the kernel. This callbacks has ability to set both
  bpf_program properties, as well as program load attributes, overriding
  and augmenting the standard libbpf handling of them;

  - optional auto-attach callback, which makes a given SEC() handler
  support auto-attachment of a BPF program through bpf_program__attach()
  API and/or BPF skeletons <skel>__attach() method.

Each callbacks gets a `long cookie` parameter passed in, which is
specified during SEC() handling. This can be used by callbacks to lookup
whatever additional information is necessary.

This is not yet completely ready to be exposed to the outside world,
mainly due to non-public nature of struct bpf_prog_load_params. Instead
of making it part of public API, we'll wait until the planned low-level
libbpf API improvements for BPF_PROG_LOAD and other typical bpf()
syscall APIs, at which point we'll have a public, probably OPTS-based,
way to fully specify BPF program load parameters, which will be used as
an interface for custom pre-load callbacks.

But this change itself is already a good first step to unify the BPF
program hanling logic even within the libbpf itself. As one example, all
the extra per-program type handling (sleepable bit, attach_btf_id
resolution, unsetting optional expected attach type) is now more obvious
and is gathered in one place.

Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Dave Marchevsky <davemarchevsky@fb.com>
Link: https://lore.kernel.org/bpf/20210928161946.2512801-6-andrii@kernel.org
2021-09-28 13:51:19 -07:00
Andrii Nakryiko
15669e1dcd selftests/bpf: Normalize all the rest SEC() uses
Normalize all the other non-conforming SEC() usages across all
selftests. This is in preparation for libbpf to start to enforce
stricter SEC() rules in libbpf 1.0 mode.

Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Dave Marchevsky <davemarchevsky@fb.com>
Link: https://lore.kernel.org/bpf/20210928161946.2512801-5-andrii@kernel.org
2021-09-28 13:51:19 -07:00
Andrii Nakryiko
c22bdd2825 selftests/bpf: Switch SEC("classifier*") usage to a strict SEC("tc")
Convert all SEC("classifier*") uses to a new and strict SEC("tc")
section name. In reference_tracking selftests switch from ambiguous
searching by program title (section name) to non-ambiguous searching by
name in some selftests, getting closer to completely removing
bpf_object__find_program_by_title().

Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20210928161946.2512801-4-andrii@kernel.org
2021-09-28 13:51:19 -07:00
Andrii Nakryiko
8fffa0e345 selftests/bpf: Normalize XDP section names in selftests
Convert almost all SEC("xdp_blah") uses to strict SEC("xdp") to comply
with strict libbpf 1.0 logic of exact section name match for XDP program
types. There is only one exception, which is only tested through
iproute2 and defines multiple XDP programs within the same BPF object.
Given iproute2 still works in non-strict libbpf mode and it doesn't have
means to specify XDP programs by its name (not section name/title),
leave that single file alone for now until iproute2 gains lookup by
function/program name.

Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Dave Marchevsky <davemarchevsky@fb.com>
Link: https://lore.kernel.org/bpf/20210928161946.2512801-3-andrii@kernel.org
2021-09-28 13:51:19 -07:00
Andrii Nakryiko
9673268f03 libbpf: Add "tc" SEC_DEF which is a better name for "classifier"
As argued in [0], add "tc" ELF section definition for SCHED_CLS BPF
program type. "classifier" is a misleading terminology and should be
migrated away from.

  [0] https://lore.kernel.org/bpf/270e27b1-e5be-5b1c-b343-51bd644d0747@iogearbox.net/

Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20210928161946.2512801-2-andrii@kernel.org
2021-09-28 13:51:19 -07:00
Johan Almbladh
29eef85be2 bpf/tests: Add tail call limit test with external function call
This patch adds a tail call limit test where the program also emits
a BPF_CALL to an external function prior to the tail call. Mainly
testing that JITed programs preserve its internal register state, for
example tail call count, across such external calls.

Signed-off-by: Johan Almbladh <johan.almbladh@anyfinetworks.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20210914091842.4186267-15-johan.almbladh@anyfinetworks.com
2021-09-28 09:26:29 +02:00
Johan Almbladh
18935a72eb bpf/tests: Fix error in tail call limit tests
This patch fixes an error in the tail call limit test that caused the
test to fail on for x86-64 JIT. Previously, the register R0 was used to
report the total number of tail calls made. However, after a tail call
fall-through, the value of the R0 register is undefined. Now, all tail
call error path tests instead use context state to store the count.

Fixes: 874be05f52 ("bpf, tests: Add tail call test suite")
Reported-by: Paul Chaignon <paul@cilium.io>
Reported-by: Tiezhu Yang <yangtiezhu@loongson.cn>
Signed-off-by: Johan Almbladh <johan.almbladh@anyfinetworks.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Tested-by: Tiezhu Yang <yangtiezhu@loongson.cn>
Link: https://lore.kernel.org/bpf/20210914091842.4186267-14-johan.almbladh@anyfinetworks.com
2021-09-28 09:26:29 +02:00
Johan Almbladh
f536a7c806 bpf/tests: Add more BPF_END byte order conversion tests
This patch adds tests of the high 32 bits of 64-bit BPF_END conversions.

It also adds a mirrored set of tests where the source bytes are reversed.
The MSB of each byte is now set on the high word instead, possibly
affecting sign-extension during conversion in a different way. Mainly
for JIT testing.

Signed-off-by: Johan Almbladh <johan.almbladh@anyfinetworks.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20210914091842.4186267-13-johan.almbladh@anyfinetworks.com
2021-09-28 09:26:29 +02:00
Johan Almbladh
f1517eb790 bpf/tests: Expand branch conversion JIT test
This patch expands the branch conversion test introduced by 66e5eb84
("bpf, tests: Add branch conversion JIT test"). The test now includes
a JMP with maximum eBPF offset. This triggers branch conversion for the
64-bit MIPS JIT. Additional variants are also added for cases when the
branch is taken or not taken.

Signed-off-by: Johan Almbladh <johan.almbladh@anyfinetworks.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20210914091842.4186267-12-johan.almbladh@anyfinetworks.com
2021-09-28 09:26:28 +02:00
Johan Almbladh
c4df4559db bpf/tests: Add JMP tests with degenerate conditional
This patch adds a set of tests for JMP and JMP32 operations where the
branch decision is know at JIT time. Mainly testing JIT behaviour.

Signed-off-by: Johan Almbladh <johan.almbladh@anyfinetworks.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20210914091842.4186267-11-johan.almbladh@anyfinetworks.com
2021-09-28 09:26:28 +02:00
Johan Almbladh
d4ff9ee2dc bpf/tests: Add JMP tests with small offsets
This patch adds a set of tests for JMP to verify that the JITed jump
offset is calculated correctly. We pretend that the verifier has inserted
any zero extensions to make the jump-over operations JIT to one
instruction each, in order to control the exact JITed jump offset.

Signed-off-by: Johan Almbladh <johan.almbladh@anyfinetworks.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20210914091842.4186267-10-johan.almbladh@anyfinetworks.com
2021-09-28 09:26:28 +02:00
Johan Almbladh
27cc6dac6e bpf/tests: Add test case flag for verifier zero-extension
This patch adds a new flag to indicate that the verified did insert
zero-extensions, even though the verifier is not being run for any
of the tests.

Signed-off-by: Johan Almbladh <johan.almbladh@anyfinetworks.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20210914091842.4186267-9-johan.almbladh@anyfinetworks.com
2021-09-28 09:26:28 +02:00
Johan Almbladh
2e80761194 bpf/tests: Add exhaustive test of LD_IMM64 immediate magnitudes
This patch adds a test for the 64-bit immediate load, a two-instruction
operation, to verify correctness for all possible magnitudes of the
immediate operand. Mainly intended for JIT testing.

Signed-off-by: Johan Almbladh <johan.almbladh@anyfinetworks.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20210914091842.4186267-8-johan.almbladh@anyfinetworks.com
2021-09-28 09:26:28 +02:00
Johan Almbladh
a7d2e752e5 bpf/tests: Add staggered JMP and JMP32 tests
This patch adds a new type of jump test where the program jumps forwards
and backwards with increasing offset. It mainly tests JITs where a
relative jump may generate different JITed code depending on the offset
size, read MIPS.

Signed-off-by: Johan Almbladh <johan.almbladh@anyfinetworks.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20210914091842.4186267-7-johan.almbladh@anyfinetworks.com
2021-09-28 09:26:28 +02:00
Johan Almbladh
a5a36544de bpf/tests: Add exhaustive tests of JMP operand magnitudes
This patch adds a set of tests for conditional JMP and JMP32 operations to
verify correctness for all possible magnitudes of the immediate and
register operands. Mainly intended for JIT testing.

Signed-off-by: Johan Almbladh <johan.almbladh@anyfinetworks.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20210914091842.4186267-6-johan.almbladh@anyfinetworks.com
2021-09-28 09:26:28 +02:00
Johan Almbladh
9298e63eaf bpf/tests: Add exhaustive tests of ALU operand magnitudes
This patch adds a set of tests for ALU64 and ALU32 arithmetic and bitwise
logical operations to verify correctness for all possible magnitudes of
the register and immediate operands. Mainly intended for JIT testing.

The patch introduces a pattern generator that can be used to drive
extensive tests of different kinds of operations. It is parameterized
to allow tuning of the operand combinations to test.

Signed-off-by: Johan Almbladh <johan.almbladh@anyfinetworks.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20210914091842.4186267-5-johan.almbladh@anyfinetworks.com
2021-09-28 09:26:28 +02:00
Johan Almbladh
68c956fe74 bpf/tests: Add exhaustive tests of ALU shift values
This patch adds a set of tests for ALU64 and ALU32 shift operations to
verify correctness for all possible values of the shift value. Mainly
intended for JIT testing.

Signed-off-by: Johan Almbladh <johan.almbladh@anyfinetworks.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20210914091842.4186267-4-johan.almbladh@anyfinetworks.com
2021-09-28 09:26:28 +02:00
Johan Almbladh
4bc354138d bpf/tests: Reduce memory footprint of test suite
The test suite used to call any fill_helper callbacks to generate eBPF
program data for all test cases at once. This caused ballooning memory
requirements as more extensive test cases were added. Now the each
fill_helper is called before the test is run and the allocated memory
released afterwards, before the next test case is processed.

Signed-off-by: Johan Almbladh <johan.almbladh@anyfinetworks.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20210914091842.4186267-3-johan.almbladh@anyfinetworks.com
2021-09-28 09:26:28 +02:00
Johan Almbladh
c2a228d69c bpf/tests: Allow different number of runs per test case
This patch allows a test cast to specify the number of runs to use. For
compatibility with existing test case definitions, the default value 0
is interpreted as MAX_TESTRUNS.

A reduced number of runs is useful for complex test programs where 1000
runs may take a very long time. Instead of reducing what is tested, one
can instead reduce the number of times the test is run.

Signed-off-by: Johan Almbladh <johan.almbladh@anyfinetworks.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20210914091842.4186267-2-johan.almbladh@anyfinetworks.com
2021-09-28 09:26:27 +02:00
Toke Høiland-Jørgensen
c3e8c44a90 libbpf: Ignore STT_SECTION symbols in 'maps' section
When parsing legacy map definitions, libbpf would error out when
encountering an STT_SECTION symbol. This becomes a problem because some
versions of binutils will produce SECTION symbols for every section when
processing an ELF file, so BPF files run through 'strip' will end up with
such symbols, making libbpf refuse to load them.

There's not really any reason why erroring out is strictly necessary, so
change libbpf to just ignore SECTION symbols when parsing the ELF.

Signed-off-by: Toke Høiland-Jørgensen <toke@redhat.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20210927205810.715656-1-toke@redhat.com
2021-09-27 21:29:37 -07:00
Daniel Borkmann
4c9f093720 Merge branch 'bpf-xsk-rx-batch'
Magnus Karlsson says:

====================
This patch set introduces a batched interface for Rx buffer allocation
in AF_XDP buffer pool. Instead of using xsk_buff_alloc(*pool), drivers
can now use xsk_buff_alloc_batch(*pool, **xdp_buff_array,
max). Instead of returning a pointer to an xdp_buff, it returns the
number of xdp_buffs it managed to allocate up to the maximum value of
the max parameter in the function call. Pointers to the allocated
xdp_buff:s are put in the xdp_buff_array supplied in the call. This
could be a SW ring that already exists in the driver or a new
structure that the driver has allocated.

  u32 xsk_buff_alloc_batch(struct xsk_buff_pool *pool,
                           struct xdp_buff **xdp,
                           u32 max);

When using this interface, the driver should also use the new
interface below to set the relevant fields in the struct xdp_buff. The
reason for this is that xsk_buff_alloc_batch() does not fill in the
data and data_meta fields for you as is the case with
xsk_buff_alloc(). So it is not sufficient to just set data_end
(effectively the size) anymore in the driver. The reason for this is
performance as explained in detail in the commit message.

  void xsk_buff_set_size(struct xdp_buff *xdp, u32 size);

Patch 6 also optimizes the buffer allocation in the aligned case. In
this case, we can skip the reinitialization of most fields in the
xdp_buff_xsk struct at allocation time. As the number of elements in
the heads array is equal to the number of possible buffers in the
umem, we can initialize them once and for all at bind time and then
just point to the correct one in the xdp_buff_array that is returned
to the driver. No reason to have a stack of free head entries. In the
unaligned case, the buffers can reside anywhere in the umem, so this
optimization is not possible as we still have to fill in the right
information in the xdp_buff every single time one is allocated.

I have updated i40e and ice to use this new batched interface.

These are the throughput results on my 2.1 GHz Cascade Lake system:

Aligned mode:
ice: +11% / -9 cycles/pkt
i40e: +12% / -9 cycles/pkt

Unaligned mode:
ice: +1.5% / -1 cycle/pkt
i40e: +1% / -1 cycle/pkt

For the aligned case, batching provides around 40% of the performance
improvement and the aligned optimization the rest, around 60%. Would
have expected a ~4% boost for unaligned with this data, but I only get
around 1%. Do not know why. Note that memory consumption in aligned
mode is also reduced by this patch set.
====================

Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2021-09-28 00:19:13 +02:00
Magnus Karlsson
e34087fc00 selftests: xsk: Add frame_headroom test
Add a test for the frame_headroom feature that can be set on the
umem. The logic added validates that all offsets in all tests and
packets are valid, not just the ones that have a specifically
configured frame_headroom.

Signed-off-by: Magnus Karlsson <magnus.karlsson@intel.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20210922075613.12186-14-magnus.karlsson@gmail.com
2021-09-28 00:18:35 +02:00