Add libbpf-internal btf_load_into_kernel() that allows to pass
preallocated log_buf and custom log_level to be passed into kernel
during BPF_BTF_LOAD call. When custom log_buf is provided,
btf_load_into_kernel() won't attempt an retry with automatically
allocated internal temporary buffer to capture BTF validation log.
It's important to note the relation between log_buf and log_level, which
slightly deviates from stricter kernel logic. From kernel's POV, if
log_buf is specified, log_level has to be > 0, and vice versa. While
kernel has good reasons to request such "sanity, this, in practice, is
a bit unconvenient and restrictive for libbpf's high-level bpf_object APIs.
So libbpf will allow to set non-NULL log_buf and log_level == 0. This is
fine and means to attempt to load BTF without logging requested, but if
it failes, retry the load with custom log_buf and log_level 1. Similar
logic will be implemented for program loading. In practice this means
that users can provide custom log buffer just in case error happens, but
not really request slower verbose logging all the time. This is also
consistent with libbpf behavior when custom log_buf is not set: libbpf
first tries to load everything with log_level=0, and only if error
happens allocates internal log buffer and retries with log_level=1.
Also, while at it, make BTF validation log more obvious and follow the log
pattern libbpf is using for dumping BPF verifier log during
BPF_PROG_LOAD. BTF loading resulting in an error will look like this:
libbpf: BTF loading error: -22
libbpf: -- BEGIN BTF LOAD LOG ---
magic: 0xeb9f
version: 1
flags: 0x0
hdr_len: 24
type_off: 0
type_len: 1040
str_off: 1040
str_len: 2063598257
btf_total_size: 1753
Total section length too long
-- END BTF LOAD LOG --
libbpf: Error loading .BTF into kernel: -22. BTF is optional, ignoring.
This makes it much easier to find relevant parts in libbpf log output.
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20211209193840.1248570-4-andrii@kernel.org
Similar to previous bpf_prog_load() and bpf_map_create() APIs, add
bpf_btf_load() API which is taking optional OPTS struct. Schedule
bpf_load_btf() for deprecation in v0.8 ([0]).
This makes naming consistent with BPF_BTF_LOAD command, sets up an API
for extensibility in the future, moves options parameters (log-related
fields) into optional options, and also allows to pass log_level
directly.
It also removes log buffer auto-allocation logic from low-level API
(consistent with bpf_prog_load() behavior), but preserves a special
treatment of log_level == 0 with non-NULL log_buf, which matches
low-level bpf_prog_load() and high-level libbpf APIs for BTF and program
loading behaviors.
[0] Closes: https://github.com/libbpf/libbpf/issues/419
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20211209193840.1248570-3-andrii@kernel.org
To unify libbpf APIs behavior w.r.t. log_buf and log_level, fix
bpf_prog_load() to follow the same logic as bpf_btf_load() and
high-level bpf_object__load() API will follow in the subsequent patches:
- if log_level is 0 and non-NULL log_buf is provided by a user, attempt
load operation initially with no log_buf and log_level set;
- if successful, we are done, return new FD;
- on error, retry the load operation with log_level bumped to 1 and
log_buf set; this way verbose logging will be requested only when we
are sure that there is a failure, but will be fast in the
common/expected success case.
Of course, user can still specify log_level > 0 from the very beginning
to force log collection.
Suggested-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20211209193840.1248570-2-andrii@kernel.org
Return value directly instead of taking this in another redundant variable.
Reported-by: Zeal Robot <zealci@zte.com.cm>
Signed-off-by: Minghao Chi <chi.minghao@zte.com.cn>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20211209080051.421844-1-chi.minghao@zte.com.cn
The pointer t is being initialized with a value that is never read. The
pointer is re-assigned a value a littler later on, hence the initialization
is redundant and can be removed.
Signed-off-by: Colin Ian King <colin.i.king@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20211207224718.59593-1-colin.i.king@gmail.com
The following warning is triggered when I used clang compiler
to build the selftest.
/.../prog_tests/btf_dedup_split.c:368:6: warning: variable 'btf2' is used uninitialized whenever 'if' condition is true [-Wsometimes-uninitialized]
if (!ASSERT_OK(err, "btf_dedup"))
^~~~~~~~~~~~~~~~~~~~~~~~~~~~
/.../prog_tests/btf_dedup_split.c:424:12: note: uninitialized use occurs here
btf__free(btf2);
^~~~
/.../prog_tests/btf_dedup_split.c:368:2: note: remove the 'if' if its condition is always false
if (!ASSERT_OK(err, "btf_dedup"))
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/.../prog_tests/btf_dedup_split.c:343:25: note: initialize the variable 'btf2' to silence this warning
struct btf *btf1, *btf2;
^
= NULL
Initialize local variable btf2 = NULL and the warning is gone.
Fixes: 9a49afe6f5 ("selftests/bpf: Add btf_dedup case with duplicated structs within CU")
Signed-off-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20211209050403.1770836-1-yhs@fb.com
bpf_create_map is deprecated. Replace it with bpf_map_create. Also add a
__weak bpf_map_create() so that when older version of libbpf is linked as
a shared library, it falls back to bpf_create_map().
Fixes: 992c422541 ("libbpf: Unify low-level map creation APIs w/ new bpf_map_create()")
Signed-off-by: Song Liu <song@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20211207232340.2561471-1-song@kernel.org
Alexander Lobakin says:
====================
Samples, at least XDP ones, can be built only with the compiler used
to build the kernel itself.
However, XDP sample infra introduced in Aug'21 was probably tested
with GCC/Binutils only as it's not really compilable for now with
Clang/LLVM.
These two are trivial fixes addressing this.
====================
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Clang doesn't have 'stringop-truncation' group like GCC does, and
complains about it when building samples which use xdp_sample_user
infra:
samples/bpf/xdp_sample_user.h:48:32: warning: unknown warning group '-Wstringop-truncation', ignored [-Wunknown-warning-option]
#pragma GCC diagnostic ignored "-Wstringop-truncation"
^
[ repeat ]
Those are harmless, but avoidable when guarding it with ifdef.
I could guard push/pop as well, but this would require one more
ifdef cruft around a single line which I don't think is reasonable.
Fixes: 156f886cf6 ("samples: bpf: Add basic infrastructure for XDP samples")
Signed-off-by: Alexander Lobakin <alexandr.lobakin@intel.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/bpf/20211203195004.5803-3-alexandr.lobakin@intel.com
Clang (13) doesn't get the jokes about specifying libraries to link in
cclags of individual .o objects:
clang-13: warning: -lm: 'linker' input unused [-Wunused-command-line-argument]
[ ... ]
LD samples/bpf/xdp_redirect_cpu
LD samples/bpf/xdp_redirect_map_multi
LD samples/bpf/xdp_redirect_map
LD samples/bpf/xdp_redirect
LD samples/bpf/xdp_monitor
/usr/bin/ld: samples/bpf/xdp_sample_user.o: in function `sample_summary_print':
xdp_sample_user.c:(.text+0x84c): undefined reference to `floor'
/usr/bin/ld: xdp_sample_user.c:(.text+0x870): undefined reference to `ceil'
/usr/bin/ld: xdp_sample_user.c:(.text+0x8cf): undefined reference to `floor'
/usr/bin/ld: xdp_sample_user.c:(.text+0x8f3): undefined reference to `ceil'
[ more ]
Specify '-lm' as ldflags for all xdp_sample_user.o users in the main
Makefile and remove it from ccflags of ^ in Makefile.target -- just
like it's done for all other samples. This works with all compilers.
Fixes: 6e1051a54e ("samples: bpf: Convert xdp_monitor to XDP samples helper")
Fixes: b926c55d85 ("samples: bpf: Convert xdp_redirect to XDP samples helper")
Fixes: e531a220cc ("samples: bpf: Convert xdp_redirect_cpu to XDP samples helper")
Fixes: bbe65865aa ("samples: bpf: Convert xdp_redirect_map to XDP samples helper")
Fixes: 594a116b2a ("samples: bpf: Convert xdp_redirect_map_multi to XDP samples helper")
Signed-off-by: Alexander Lobakin <alexandr.lobakin@intel.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/bpf/20211203195004.5803-2-alexandr.lobakin@intel.com
When CONFIG_DEBUG_INFO_BTF_MODULES is not set
the following warning can be seen:
kernel/bpf/btf.c:6588:13: warning: 'purge_cand_cache' defined but not used [-Wunused-function]
Fix it.
Fixes: 1e89106da2 ("bpf: Add bpf_core_add_cands() and wire it into bpf_core_apply_relo_insn().")
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20211207014839.6976-1-alexei.starovoitov@gmail.com
This adds comments above functions in libbpf.h which document
their uses. These comments are of a format that doxygen and sphinx
can pick up and render. These are rendered by libbpf.readthedocs.org
These doc comments are for:
- bpf_object__open_file()
- bpf_object__open_mem()
- bpf_program__attach_uprobe()
- bpf_program__attach_uprobe_opts()
Signed-off-by: Grant Seltzer <grantseltzer@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20211206203709.332530-1-grantseltzer@gmail.com
Branch data available to BPF programs can be very useful to get stack traces
out of userspace application.
Commit fff7b64355 ("bpf: Add bpf_read_branch_records() helper") added BPF
support to capture branch records in x86. Enable this feature also for other
architectures as well by removing checks specific to x86.
If an architecture doesn't support branch records, bpf_read_branch_records()
still has appropriate checks and it will return an -EINVAL in that scenario.
Based on UAPI helper doc in include/uapi/linux/bpf.h, unsupported architectures
should return -ENOENT in such case. Hence, update the appropriate check to
return -ENOENT instead.
Selftest 'perf_branches' result on power9 machine which has the branch stacks
support:
- Before this patch:
[command]# ./test_progs -t perf_branches
#88/1 perf_branches/perf_branches_hw:FAIL
#88/2 perf_branches/perf_branches_no_hw:OK
#88 perf_branches:FAIL
Summary: 0/1 PASSED, 0 SKIPPED, 1 FAILED
- After this patch:
[command]# ./test_progs -t perf_branches
#88/1 perf_branches/perf_branches_hw:OK
#88/2 perf_branches/perf_branches_no_hw:OK
#88 perf_branches:OK
Summary: 1/2 PASSED, 0 SKIPPED, 0 FAILED
Selftest 'perf_branches' result on power9 machine which doesn't have branch
stack report:
- After this patch:
[command]# ./test_progs -t perf_branches
#88/1 perf_branches/perf_branches_hw:SKIP
#88/2 perf_branches/perf_branches_no_hw:OK
#88 perf_branches:OK
Summary: 1/1 PASSED, 1 SKIPPED, 0 FAILED
Fixes: fff7b64355 ("bpf: Add bpf_read_branch_records() helper")
Suggested-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Kajol Jain <kjain@linux.ibm.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20211206073315.77432-1-kjain@linux.ibm.com
BPF_LOG_KERNEL is only used internally, so disallow bpf_btf_load()
to set log level as BPF_LOG_KERNEL. The same checking has already
been done in bpf_check(), so factor out a helper to check the
validity of log attributes and use it in both places.
Fixes: 8580ac9404 ("bpf: Process in-kernel BTF")
Signed-off-by: Hou Tao <houtao1@huawei.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Yonghong Song <yhs@fb.com>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Link: https://lore.kernel.org/bpf/20211203053001.740945-1-houtao1@huawei.com
The test for bpf_iter_task_vma assumes that the output will be longer
than 1 kB, as the comment above the loop says. Due to this assumption,
the loop becomes infinite if the output turns to be shorter than 1 kB.
The return value of read_fd_into_buffer is 0 when the end of file was
reached, and len isn't being increased any more.
This commit adds a break on EOF to handle short output correctly. For
the reference, this is the contents that I get when running test_progs
under vmtest.sh, and it's shorter than 1 kB:
00400000-00401000 r--p 00000000 fe:00 25867 /root/bpf/test_progs
00401000-00674000 r-xp 00001000 fe:00 25867 /root/bpf/test_progs
00674000-0095f000 r--p 00274000 fe:00 25867 /root/bpf/test_progs
0095f000-00983000 r--p 0055e000 fe:00 25867 /root/bpf/test_progs
00983000-00a8a000 rw-p 00582000 fe:00 25867 /root/bpf/test_progs
00a8a000-0484e000 rw-p 00000000 00:00 0
7f6c64000000-7f6c64021000 rw-p 00000000 00:00 0
7f6c64021000-7f6c68000000 ---p 00000000 00:00 0
7f6c6ac8f000-7f6c6ac90000 r--s 00000000 00:0d 8032
anon_inode:bpf-map
7f6c6ac90000-7f6c6ac91000 ---p 00000000 00:00 0
7f6c6ac91000-7f6c6b491000 rw-p 00000000 00:00 0
7f6c6b491000-7f6c6b492000 r--s 00000000 00:0d 8032
anon_inode:bpf-map
7f6c6b492000-7f6c6b493000 rw-s 00000000 00:0d 8032
anon_inode:bpf-map
7ffc1e23d000-7ffc1e25e000 rw-p 00000000 00:00 0
7ffc1e3b8000-7ffc1e3bc000 r--p 00000000 00:00 0
7ffc1e3bc000-7ffc1e3bd000 r-xp 00000000 00:00 0
7fffffffe000-7ffffffff000 --xp 00000000 00:00 0
Fixes: e8168840e1 ("selftests/bpf: Add test for bpf_iter_task_vma")
Signed-off-by: Maxim Mikityanskiy <maximmi@nvidia.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20211130181811.594220-1-maximmi@nvidia.com
Libbpf development version was bumped to 0.7 in c93faaaf2f
("libbpf: Deprecate bpf_prog_load_xattr() API"), activating a bunch of
previously scheduled deprecations. Most APIs are pretty straightforward
to replace with newer APIs, but perf has a complicated mixed setup with
libbpf used both as static and shared configurations, which makes it
non-trivial to migrate the APIs.
Further, bpf_program__set_prep() needs more involved refactoring, which
will require help from Arnaldo and/or Jiri.
So for now, mute deprecation warnings and work on migrating perf off of
deprecated APIs separately with the input from owners of the perf tool.
Fixes: c93faaaf2f ("libbpf: Deprecate bpf_prog_load_xattr() API")
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20211203004640.2455717-1-andrii@kernel.org
Andrii Nakryiko says:
====================
Few lines in the last patch to mark bpf_prog_load_xattr() deprecated required
a decent amount of clean ups in all the other patches. samples/bpf is big part
of the clean up.
This patch set also bumps libbpf version to 0.7, as libbpf v0.6 release will
be cut shortly.
====================
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
bpf_prog_load_xattr() is high-level API that's named as a low-level
BPF_PROG_LOAD wrapper APIs, but it actually operates on struct
bpf_object. It's badly and confusingly misnamed as it will load all the
progs insige bpf_object, returning prog_fd of the very first BPF
program. It also has a bunch of ad-hoc things like log_level override,
map_ifindex auto-setting, etc. All this can be expressed more explicitly
and cleanly through existing libbpf APIs. This patch marks
bpf_prog_load_xattr() for deprecation in libbpf v0.8 ([0]).
[0] Closes: https://github.com/libbpf/libbpf/issues/308
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20211201232824.3166325-10-andrii@kernel.org
Replace deprecated APIs with new ones. Also mute source code using
deprecated AF_XDP (xsk.h). Figuring out what to do with all the AF_XDP
stuff is a separate problem that should be solved with its own set of
changes.
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20211201232824.3166325-9-andrii@kernel.org
Remove xdp_samples_user.o rule redefinition which generates Makefile
warning and instead override TPROGS_CFLAGS. This seems to work fine when
building inside selftests/bpf.
That was one big head-scratcher before I found that generic
Makefile.target hid this surprising specialization for for xdp_samples_user.o.
Main change is to use actual locally installed libbpf headers.
Also drop printk macro re-definition (not even used!).
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20211201232824.3166325-8-andrii@kernel.org
Migrate all the selftests that were still using bpf_prog_load_xattr().
Few are converted to skeleton, others will use bpf_object__open_file()
API.
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20211201232824.3166325-7-andrii@kernel.org
xdpxceiver.c is using AF_XDP APIs that are deprecated starting from
libbpf 0.7. Until we migrate the test to libxdp or solve this issue in
some other way, mute deprecation warnings within xdpxceiver.c.
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20211201232824.3166325-6-andrii@kernel.org
Add bpf_program__set_log_level() and bpf_program__log_level() to fetch
and adjust log_level sent during BPF_PROG_LOAD command. This allows to
selectively request more or less verbose output in BPF verifier log.
Also bump libbpf version to 0.7 and make these APIs the first in v0.7.
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20211201232824.3166325-3-andrii@kernel.org
The test_cmpxchg() and test_xchg() functions say "test_run add".
Therefore, make them say "test_run cmpxchg" and "test_run xchg",
respectively.
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20211201005030.GA3071525@paulmck-ThinkPad-P17-Gen-1
Add $(OUTPUT) prefix to testing_helpers.o, so it can be built out of
tree when necessary. At the moment, in addition to being built in-tree
even when out-of-tree is required, testing_helpers.o is not built with
the right recipe when cross-building.
For consistency the other helpers, cgroup_helpers and trace_helpers, can
also be passed as objects instead of source. Use *_HELPERS variable to
keep the Makefile readable.
Fixes: f87c1930ac ("selftests/bpf: Merge test_stub.c into testing_helpers.c")
Signed-off-by: Jean-Philippe Brucker <jean-philippe@linaro.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20211201145101.823159-1-jean-philippe@linaro.org
Alexei Starovoitov says:
====================
From: Alexei Starovoitov <ast@kernel.org>
v4->v5:
. Reduce number of memory allocations in candidate cache logic
. Fix couple UAF issues
. Add Andrii's patch to cleanup struct bpf_core_cand
. More thorough tests
. Planned followups:
- support -v in lskel
- move struct bpf_core_spec out of bpf_core_apply_relo_insn to
reduce stack usage
- implement bpf_core_types_are_compat
v3->v4:
. complete refactor of find candidates logic.
Now it has small permanent cache.
. Fix a bug in gen_loader related to attach_kind.
. Fix BTF log size limit.
. More tests.
v2->v3:
. addressed Andrii's feedback in every patch.
New field in union bpf_attr changed from "core_relo" to "core_relos".
. added one more test and checkpatch.pl-ed the set.
v1->v2:
. Refactor uapi to pass 'struct bpf_core_relo' from LLVM into libbpf and further
into the kernel instead of bpf_core_apply_relo() bpf helper. Because of this
change the CO-RE algorithm has an ability to log error and debug events through
the standard bpf verifer log mechanism which was not possible with helper
approach.
. #define RELO_CORE macro was removed and replaced with btf_member_bit_offset() patch.
This set introduces CO-RE support in the kernel.
There are several reasons to add such support:
1. It's a step toward signed BPF programs.
2. It allows golang like languages that struggle to adopt libbpf
to take advantage of CO-RE powers.
3. Currently the field accessed by 'ldx [R1 + 10]' insn is recognized
by the verifier purely based on +10 offset. If R1 points to a union
the verifier picks one of the fields at this offset.
With CO-RE the kernel can disambiguate the field access.
Alexei Starovoitov (16):
libbpf: Replace btf__type_by_id() with btf_type_by_id().
bpf: Rename btf_member accessors.
bpf: Prepare relo_core.c for kernel duty.
bpf: Define enum bpf_core_relo_kind as uapi.
bpf: Pass a set of bpf_core_relo-s to prog_load command.
bpf: Adjust BTF log size limit.
bpf: Add bpf_core_add_cands() and wire it into
bpf_core_apply_relo_insn().
libbpf: Use CO-RE in the kernel in light skeleton.
libbpf: Support init of inner maps in light skeleton.
libbpf: Clean gen_loader's attach kind.
selftests/bpf: Add lskel version of kfunc test.
selftests/bpf: Improve inner_map test coverage.
selftests/bpf: Convert map_ptr_kern test to use light skeleton.
selftests/bpf: Additional test for CO-RE in the kernel.
selftests/bpf: Revert CO-RE removal in test_ksyms_weak.
selftests/bpf: Add CO-RE relocations to verifier scale test.
====================
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
The commit 087cba799c ("selftests/bpf: Add weak/typeless ksym test for light skeleton")
added test_ksyms_weak to light skeleton testing, but remove CO-RE access.
Revert that part of commit, since light skeleton can use CO-RE in the kernel.
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20211201181040.23337-17-alexei.starovoitov@gmail.com
Add a test where randmap() function is appended to three different bpf
programs. That action checks struct bpf_core_relo replication logic
and offset adjustment in gen loader part of libbpf.
Fourth bpf program has 360 CO-RE relocations from vmlinux, bpf_testmod,
and non-existing type. It tests candidate cache logic.
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20211201181040.23337-16-alexei.starovoitov@gmail.com
The gen_loader has to clear attach_kind otherwise the programs
without attach_btf_id will fail load if they follow programs
with attach_btf_id.
Fixes: 6723474373 ("libbpf: Generate loader program out of BPF ELF file.")
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20211201181040.23337-12-alexei.starovoitov@gmail.com
Without lskel the CO-RE relocations are processed by libbpf before any other
work is done. Instead, when lskel is needed, remember relocation as RELO_CORE
kind. Then when loader prog is generated for a given bpf program pass CO-RE
relos of that program to gen loader via bpf_gen__record_relo_core(). The gen
loader will remember them as-is and pass it later as-is into the kernel.
The normal libbpf flow is to process CO-RE early before call relos happen. In
case of gen_loader the core relos have to be added to other relos to be copied
together when bpf static function is appended in different places to other main
bpf progs. During the copy the append_subprog_relos() will adjust insn_idx for
normal relos and for RELO_CORE kind too. When that is done each struct
reloc_desc has good relos for specific main prog.
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20211201181040.23337-10-alexei.starovoitov@gmail.com
Given BPF program's BTF root type name perform the following steps:
. search in vmlinux candidate cache.
. if (present in cache and candidate list >= 1) return candidate list.
. do a linear search through kernel BTFs for possible candidates.
. regardless of number of candidates found populate vmlinux cache.
. if (candidate list >= 1) return candidate list.
. search in module candidate cache.
. if (present in cache) return candidate list (even if list is empty).
. do a linear search through BTFs of all kernel modules
collecting candidates from all of them.
. regardless of number of candidates found populate module cache.
. return candidate list.
Then wire the result into bpf_core_apply_relo_insn().
When BPF program is trying to CO-RE relocate a type
that doesn't exist in either vmlinux BTF or in modules BTFs
these steps will perform 2 cache lookups when cache is hit.
Note the cache doesn't prevent the abuse by the program that might
have lots of relocations that cannot be resolved. Hence cond_resched().
CO-RE in the kernel requires CAP_BPF, since BTF loading requires it.
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20211201181040.23337-9-alexei.starovoitov@gmail.com
Make BTF log size limit to be the same as the verifier log size limit.
Otherwise tools that progressively increase log size and use the same log
for BTF loading and program loading will be hitting hard to debug EINVAL.
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20211201181040.23337-7-alexei.starovoitov@gmail.com
struct bpf_core_relo is generated by llvm and processed by libbpf.
It's a de-facto uapi.
With CO-RE in the kernel the struct bpf_core_relo becomes uapi de-jure.
Add an ability to pass a set of 'struct bpf_core_relo' to prog_load command
and let the kernel perform CO-RE relocations.
Note the struct bpf_line_info and struct bpf_func_info have the same
layout when passed from LLVM to libbpf and from libbpf to the kernel
except "insn_off" fields means "byte offset" when LLVM generates it.
Then libbpf converts it to "insn index" to pass to the kernel.
The struct bpf_core_relo's "insn_off" field is always "byte offset".
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20211201181040.23337-6-alexei.starovoitov@gmail.com
enum bpf_core_relo_kind is generated by llvm and processed by libbpf.
It's a de-facto uapi.
With CO-RE in the kernel the bpf_core_relo_kind values become uapi de-jure.
Also rename them with BPF_CORE_ prefix to distinguish from conflicting names in
bpf_core_read.h. The enums bpf_field_info_kind, bpf_type_id_kind,
bpf_type_info_kind, bpf_enum_value_kind are passing different values from bpf
program into llvm.
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20211201181040.23337-5-alexei.starovoitov@gmail.com
Make relo_core.c to be compiled for the kernel and for user space libbpf.
Note the patch is reducing BPF_CORE_SPEC_MAX_LEN from 64 to 32.
This is the maximum number of nested structs and arrays.
For example:
struct sample {
int a;
struct {
int b[10];
};
};
struct sample *s = ...;
int *y = &s->b[5];
This field access is encoded as "0:1:0:5" and spec len is 4.
The follow up patch might bump it back to 64.
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20211201181040.23337-4-alexei.starovoitov@gmail.com
Rename btf_member_bit_offset() and btf_member_bitfield_size() to
avoid conflicts with similarly named helpers in libbpf's btf.h.
Rename the kernel helpers, since libbpf helpers are part of uapi.
Suggested-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20211201181040.23337-3-alexei.starovoitov@gmail.com
To prepare relo_core.c to be compiled in the kernel and the user space
replace btf__type_by_id with btf_type_by_id.
In libbpf btf__type_by_id and btf_type_by_id have different behavior.
bpf_core_apply_relo_insn() needs behavior of uapi btf__type_by_id
vs internal btf_type_by_id, but type_id range check is already done
in bpf_core_apply_relo(), so it's safe to replace it everywhere.
The kernel btf_type_by_id() does the check anyway. It doesn't hurt.
Suggested-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20211201181040.23337-2-alexei.starovoitov@gmail.com
Fix the following samples/bpf build error appeared after the
introduction of bpf_map_create() in libbpf:
CC samples/bpf/fds_example.o
samples/bpf/fds_example.c:49:12: error: static declaration of 'bpf_map_create' follows non-static declaration
static int bpf_map_create(void)
^
samples/bpf/libbpf/include/bpf/bpf.h:55:16: note: previous declaration is here
LIBBPF_API int bpf_map_create(enum bpf_map_type map_type,
^
samples/bpf/fds_example.c:82:23: error: too few arguments to function call, expected 6, have 0
fd = bpf_map_create();
~~~~~~~~~~~~~~ ^
samples/bpf/libbpf/include/bpf/bpf.h:55:16: note: 'bpf_map_create' declared here
LIBBPF_API int bpf_map_create(enum bpf_map_type map_type,
^
2 errors generated.
fds_example by accident has a static function with the same name.
It's not worth it to separate a single call into its own function,
so just embed it.
Fixes: 992c422541 ("libbpf: Unify low-level map creation APIs w/ new bpf_map_create()")
Signed-off-by: Alexander Lobakin <alexandr.lobakin@intel.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Reviewed-by: Maciej Fijalkowski <maciej.fijalkowski@intel.com>
Acked-by: Toke Høiland-Jørgensen <toke@redhat.com>
Link: https://lore.kernel.org/bpf/20211201164931.47357-1-alexandr.lobakin@intel.com
