Commit Graph

49 Commits

Author SHA1 Message Date
Andrii Nakryiko
115c0e02cb libbpf: identify maps by section index in addition to offset
To support maps to be defined in multiple sections, it's important to
identify map not just by offset within its section, but section index as
well. This patch adds tracking of section index.

For global data, we record section index of corresponding
.data/.bss/.rodata ELF section for uniformity, and thus don't need
a special value of offset for those maps.

Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Acked-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2019-07-08 12:52:46 -07:00
Andrii Nakryiko
67057c6b7d libbpf: refactor map initialization
User and global data maps initialization has gotten pretty complicated
and unnecessarily convoluted. This patch splits out the logic for global
data map and user-defined map initialization. It also removes the
restriction of pre-calculating how many maps will be initialized,
instead allowing to keep adding new maps as they are discovered, which
will be used later for BTF-defined map definitions.

Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Acked-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2019-07-08 12:52:46 -07:00
Andrii Nakryiko
bdf65f9fea libbpf: streamline ELF parsing error-handling
Simplify ELF parsing logic by exiting early, as there is no common clean
up path to execute. That makes it unnecessary to track when err was set
and when it was cleared. It also reduces nesting in some places.

Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Acked-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2019-07-08 12:52:46 -07:00
Andrii Nakryiko
0559e41969 libbpf: extract BTF loading logic
As a preparation for adding BTF-based BPF map loading, extract .BTF and
.BTF.ext loading logic.

Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Acked-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2019-07-08 12:52:46 -07:00
Daniel Borkmann
76ff616fcd bpf, libbpf: enable recvmsg attach types
Another trivial patch to libbpf in order to enable identifying and
attaching programs to BPF_CGROUP_UDP{4,6}_RECVMSG by section name.

Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2019-07-08 12:52:46 -07:00
Michal Rostecki
ddba4024c0 libbpf: Return btf_fd for load_sk_storage_btf
Before this change, function load_sk_storage_btf expected that
libbpf__probe_raw_btf was returning a BTF descriptor, but in fact it was
returning an information about whether the probe was successful (0 or
1). load_sk_storage_btf was using that value as an argument of the close
function, which was resulting in closing stdout and thus terminating the
process which called that function.

That bug was visible in bpftool. `bpftool feature` subcommand was always
exiting too early (because of closed stdout) and it didn't display all
requested probes. `bpftool -j feature` or `bpftool -p feature` were not
returning a valid json object.

This change renames the libbpf__probe_raw_btf function to
libbpf__load_raw_btf, which now returns a BTF descriptor, as expected in
load_sk_storage_btf.

v2:
- Fix typo in the commit message.

v3:
- Simplify BTF descriptor handling in bpf_object__probe_btf_* functions.
- Rename libbpf__probe_raw_btf function to libbpf__load_raw_btf and
return a BTF descriptor.

v4:
- Fix typo in the commit message.

Fixes: d7c4b3980c18 ("libbpf: detect supported kernel BTF features and sanitize BTF")
Signed-off-by: Michal Rostecki <mrostecki@opensuse.org>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Acked-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2019-07-08 12:52:46 -07:00
Andrii Nakryiko
21742bc952 libbpf: fix check for presence of associated BTF for map creation
Kernel internally checks that either key or value type ID is specified,
before using btf_fd. Do the same in libbpf's map creation code for
determining when to retry map creation w/o BTF.

Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Fixes: fba01a0689a9 ("libbpf: use negative fd to specify missing BTF")
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2019-06-14 16:53:36 -07:00
Hechao Li
49967c1f5a bpf: add a new API libbpf_num_possible_cpus()
Adding a new API libbpf_num_possible_cpus() that helps user with
per-CPU map operations.

Signed-off-by: Hechao Li <hechaol@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2019-06-11 10:18:48 -07:00
Andrii Nakryiko
fcbc2604c8 libbpf: reduce unnecessary line wrapping
There are a bunch of lines of code or comments that are unnecessary
wrapped into multi-lines. Fix that without violating any code
guidelines.

Acked-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2019-06-11 10:18:48 -07:00
Andrii Nakryiko
896c231d8c libbpf: typo and formatting fixes
A bunch of typo and formatting fixes.

Acked-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2019-06-11 10:18:48 -07:00
Andrii Nakryiko
e13049a667 libbpf: simplify two pieces of logic
Extra check for type is unnecessary in first case.

Extra zeroing is unnecessary, as snprintf guarantees that it will
zero-terminate string.

Acked-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2019-06-11 10:18:48 -07:00
Andrii Nakryiko
8e01ffc179 libbpf: use negative fd to specify missing BTF
0 is a valid FD, so it's better to initialize it to -1, as is done in
other places. Also, technically, BTF type ID 0 is valid (it's a VOID
type), so it's more reliable to check btf_fd, instead of
btf_key_type_id, to determine if there is any BTF associated with a map.

Acked-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2019-06-11 10:18:48 -07:00
Andrii Nakryiko
c7b8b2e3a5 libbpf: fix error code returned on corrupted ELF
All of libbpf errors are negative, except this one. Fix it.

Acked-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2019-06-11 10:18:48 -07:00
Andrii Nakryiko
e977af8516 libbpf: check map name retrieved from ELF
Validate there was no error retrieving symbol name corresponding to
a BPF map.

Acked-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2019-06-11 10:18:48 -07:00
Andrii Nakryiko
dd55058989 libbpf: simplify endianness check
Rewrite endianness check to use "more canonical" way, using
compiler-defined macros, similar to few other places in libbpf. It also
is more obvious and shorter.

Acked-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2019-06-11 10:18:48 -07:00
Andrii Nakryiko
64852b2fb9 libbpf: preserve errno before calling into user callback
pr_warning ultimately may call into user-provided callback function,
which can clobber errno value, so we need to save it before that.

Acked-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2019-06-11 10:18:48 -07:00
Andrii Nakryiko
1aedc35d5d libbpf: fix detection of corrupted BPF instructions section
Ensure that size of a section w/ BPF instruction is exactly a multiple
of BPF instruction size.

Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Acked-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2019-06-11 10:18:48 -07:00
Quentin Monnet
d5013de6a5 libbpf: prevent overwriting of log_level in bpf_object__load_progs()
There are two functions in libbpf that support passing a log_level
parameter for the verifier for loading programs:
bpf_object__load_xattr() and bpf_prog_load_xattr(). Both accept an
attribute object containing the log_level, and apply it to the programs
to load.

It turns out that to effectively load the programs, the latter function
eventually relies on the former. This was not taken into account when
adding support for log_level in bpf_object__load_xattr(), and the
log_level passed to bpf_prog_load_xattr() later gets overwritten with a
zero value, thus disabling verifier logs for the program in all cases:

bpf_prog_load_xattr()             // prog->log_level = attr1->log_level;
-> bpf_object__load()             // attr2->log_level = 0;
   -> bpf_object__load_xattr()    // <pass prog and attr2>
      -> bpf_object__load_progs() // prog->log_level = attr2->log_level;

Fix this by OR-ing the log_level in bpf_object__load_progs(), instead of
overwriting it.

v2: Fix commit log description (confusion on function names in v1).

Fixes: 60276f984998 ("libbpf: add bpf_object__load_xattr() API function to pass log_level")
Reported-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Quentin Monnet <quentin.monnet@netronome.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2019-06-11 10:18:48 -07:00
Quentin Monnet
d714245dd9 libbpf: add bpf_object__load_xattr() API function to pass log_level
libbpf was recently made aware of the log_level attribute for programs,
used to specify the level of information expected to be dumped by the
verifier. Function bpf_prog_load_xattr() got support for this log_level
parameter.

But some applications using libbpf rely on another function to load
programs, bpf_object__load(), which does accept any parameter for log
level. Create an API function based on bpf_object__load(), but accepting
an "attr" object as a parameter. Then add a log_level field to that
object, so that applications calling the new bpf_object__load_xattr()
can pick the desired log level.

v3:
- Rewrite commit log.

v2:
- We are in a new cycle, bump libbpf extraversion number.

Signed-off-by: Quentin Monnet <quentin.monnet@netronome.com>
Reviewed-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2019-05-29 10:27:27 -07:00
Hariprasad Kelam
1d0ddcdbda libbpf: fix warning that PTR_ERR_OR_ZERO can be used
Fix below warning reported by coccicheck:

/tools/lib/bpf/libbpf.c:3461:1-3: WARNING: PTR_ERR_OR_ZERO can be used

Signed-off-by: Hariprasad Kelam <hariprasad.kelam@gmail.com>
Acked-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2019-05-29 10:27:27 -07:00
Jiong Wang
edf3123942 libbpf: add "prog_flags" to bpf_program/bpf_prog_load_attr/bpf_load_program_attr
libbpf doesn't allow passing "prog_flags" during bpf program load in a
couple of load related APIs, "bpf_load_program_xattr", "load_program" and
"bpf_prog_load_xattr".

It makes sense to allow passing "prog_flags" which is useful for
customizing program loading.

Reviewed-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: Jiong Wang <jiong.wang@netronome.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2019-05-29 10:27:27 -07:00
Andrii Nakryiko
51dc322283 libbpf: move logging helpers into libbpf_internal.h
libbpf_util.h header was recently exposed as public as a dependency of
xsk.h. In addition to memory barriers, it contained logging helpers,
which are not supposed to be exposed. This patch moves those into
libbpf_internal.h, which is kept as an internal header.

Cc: Stanislav Fomichev <sdf@google.com>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Fixes: 7080da890984 ("libbpf: add libbpf_util.h to header install.")
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2019-05-23 15:09:13 -07:00
Stanislav Fomichev
256cf5fa87 libbpf: don't fail when feature probing fails
Otherwise libbpf is unusable from unprivileged process with
kernel.kernel.unprivileged_bpf_disabled=1.
All I get is EPERM from the probes, even if I just want to
open an ELF object and look at what progs/maps it has.

Instead of dying on probes, let's just pr_debug the error and
try to continue.

Signed-off-by: Stanislav Fomichev <sdf@google.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2019-05-23 15:09:13 -07:00
Andrii Nakryiko
c1cdd86d6b libbpf: detect supported kernel BTF features and sanitize BTF
Depending on used versions of libbpf, Clang, and kernel, it's possible to
have valid BPF object files with valid BTF information, that still won't
load successfully due to Clang emitting newer BTF features (e.g.,
BTF_KIND_FUNC, .BTF.ext's line_info/func_info, BTF_KIND_DATASEC, etc), that
are not yet supported by older kernel.

This patch adds detection of BTF features and sanitizes BPF object's BTF
by substituting various supported BTF kinds, which have compatible layout:
  - BTF_KIND_FUNC -> BTF_KIND_TYPEDEF
  - BTF_KIND_FUNC_PROTO -> BTF_KIND_ENUM
  - BTF_KIND_VAR -> BTF_KIND_INT
  - BTF_KIND_DATASEC -> BTF_KIND_STRUCT

Replacement is done in such a way as to preserve as much information as
possible (names, sizes, etc) where possible without violating kernel's
validation rules.

v2->v3:
  - remove duplicate #defines from libbpf_util.h

v1->v2:
  - add internal libbpf_internal.h w/ common stuff
  - switch SK storage BTF to use new libbpf__probe_raw_btf()

Reported-by: Alexei Starovoitov <ast@fb.com>
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2019-05-16 09:40:04 -07:00
Matt Mullins
540d704584 tools: sync bpf.h
This adds BPF_PROG_TYPE_RAW_TRACEPOINT_WRITABLE, and fixes up the

	error: enumeration value ‘BPF_PROG_TYPE_RAW_TRACEPOINT_WRITABLE’ not handled in switch [-Werror=switch-enum]

build errors it would otherwise cause in libbpf.

Signed-off-by: Matt Mullins <mmullins@fb.com>
Acked-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2019-05-16 09:40:04 -07:00
Daniel Borkmann
72ef206260 bpf, libbpf: fix segfault in bpf_object__init_maps' pr_debug statement
Ran into it while testing; in bpf_object__init_maps() data can be NULL
in the case where no map section is present. Therefore we simply cannot
access data->d_size before NULL test. Move the pr_debug() where it's
safe to access.

Fixes: d859900c4c56 ("bpf, libbpf: support global data/bss/rodata sections")
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2019-05-16 09:40:04 -07:00
Daniel Borkmann
29e229ef14 bpf, libbpf: handle old kernels more graceful wrt global data sections
Andrii reported a corner case where e.g. global static data is present
in the BPF ELF file in form of .data/.bss/.rodata section, but without
any relocations to it. Such programs could be loaded before commit
d859900c4c56 ("bpf, libbpf: support global data/bss/rodata sections"),
whereas afterwards if kernel lacks support then loading would fail.

Add a probing mechanism which skips setting up libbpf internal maps
in case of missing kernel support. In presence of relocation entries,
we abort the load attempt.

Fixes: d859900c4c56 ("bpf, libbpf: support global data/bss/rodata sections")
Reported-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2019-05-16 09:40:04 -07:00
Andrii Nakryiko
6afcd645c8 libbpf: fix printf formatter for ptrdiff_t argument
Using %ld for printing out value of ptrdiff_t type is not portable
between 32-bit and 64-bit archs. This is causing compilation errors for
libbpf on 32-bit platform (discovered as part of an effort to integrate
libbpf into systemd ([0])). Proper formatter is %td, which is used in
this patch.

v2->v1:
  - add Reported-by
  - provide more context on how this issue was discovered

[0] https://github.com/systemd/systemd/pull/12151

Reported-by: Evgeny Vereshchagin <evvers@ya.ru>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Alexei Starovoitov <ast@fb.com>
Cc: Yonghong Song <yhs@fb.com>
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Acked-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2019-04-19 09:52:37 -07:00
Andrey Ignatov
6cf6bed724 libbpf: Support sysctl hook
Support BPF_PROG_TYPE_CGROUP_SYSCTL program in libbpf: identifying
program and attach types by section name, probe.

Signed-off-by: Andrey Ignatov <rdna@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2019-04-19 09:52:37 -07:00
Andrey Ignatov
ac2254d0ea libbpf: Fix build with gcc-8
Reported in [1].

With gcc 8.3.0 the following error is issued:

  cc -Ibpf@sta -I. -I.. -I.././include -I.././include/uapi
  -fdiagnostics-color=always -fsanitize=address,undefined -fno-omit-frame-pointer
  -pipe -D_FILE_OFFSET_BITS=64 -Wall -Winvalid-pch -Werror -g -fPIC -g -O2
  -Werror -Wall -Wno-pointer-arith -Wno-sign-compare  -MD -MQ
  'bpf@sta/src_libbpf.c.o' -MF 'bpf@sta/src_libbpf.c.o.d' -o
  'bpf@sta/src_libbpf.c.o' -c ../src/libbpf.c
  ../src/libbpf.c: In function 'bpf_object__elf_collect':
  ../src/libbpf.c:947:18: error: 'map_def_sz' may be used uninitialized in this
  function [-Werror=maybe-uninitialized]
     if (map_def_sz <= sizeof(struct bpf_map_def)) {
         ~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  ../src/libbpf.c:827:18: note: 'map_def_sz' was declared here
    int i, map_idx, map_def_sz, nr_syms, nr_maps = 0, nr_maps_glob = 0;
                    ^~~~~~~~~~

According to [2] -Wmaybe-uninitialized is enabled by -Wall.
Same error is generated by clang's -Wconditional-uninitialized.

[1] https://github.com/libbpf/libbpf/pull/29#issuecomment-481902601
[2] https://gcc.gnu.org/onlinedocs/gcc/Warning-Options.html

Fixes: d859900c4c56 ("bpf, libbpf: support global data/bss/rodata sections")
Reported-by: Evgeny Vereshchagin <evvers@ya.ru>
Signed-off-by: Andrey Ignatov <rdna@fb.com>
Acked-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2019-04-11 09:01:12 -07:00
Daniel Borkmann
0c4ac0d576 bpf, libbpf: add support for BTF Var and DataSec
This adds libbpf support for BTF Var and DataSec kinds. Main point
here is that libbpf needs to do some preparatory work before the
whole BTF object can be loaded into the kernel, that is, fixing up
of DataSec size taken from the ELF section size and non-static
variable offset which needs to be taken from the ELF's string section.

Upstream LLVM doesn't fix these up since at time of BTF emission
it is too early in the compilation process thus this information
isn't available yet, hence loader needs to take care of it.

Note, deduplication handling has not been in the scope of this work
and needs to be addressed in a future commit.

Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://reviews.llvm.org/D59441
Acked-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2019-04-10 14:27:33 -07:00
Daniel Borkmann
d99a28343f bpf, libbpf: support global data/bss/rodata sections
This work adds BPF loader support for global data sections
to libbpf. This allows to write BPF programs in more natural
C-like way by being able to define global variables and const
data.

Back at LPC 2018 [0] we presented a first prototype which
implemented support for global data sections by extending BPF
syscall where union bpf_attr would get additional memory/size
pair for each section passed during prog load in order to later
add this base address into the ldimm64 instruction along with
the user provided offset when accessing a variable. Consensus
from LPC was that for proper upstream support, it would be
more desirable to use maps instead of bpf_attr extension as
this would allow for introspection of these sections as well
as potential live updates of their content. This work follows
this path by taking the following steps from loader side:

 1) In bpf_object__elf_collect() step we pick up ".data",
    ".rodata", and ".bss" section information.

 2) If present, in bpf_object__init_internal_map() we add
    maps to the obj's map array that corresponds to each
    of the present sections. Given section size and access
    properties can differ, a single entry array map is
    created with value size that is corresponding to the
    ELF section size of .data, .bss or .rodata. These
    internal maps are integrated into the normal map
    handling of libbpf such that when user traverses all
    obj maps, they can be differentiated from user-created
    ones via bpf_map__is_internal(). In later steps when
    we actually create these maps in the kernel via
    bpf_object__create_maps(), then for .data and .rodata
    sections their content is copied into the map through
    bpf_map_update_elem(). For .bss this is not necessary
    since array map is already zero-initialized by default.
    Additionally, for .rodata the map is frozen as read-only
    after setup, such that neither from program nor syscall
    side writes would be possible.

 3) In bpf_program__collect_reloc() step, we record the
    corresponding map, insn index, and relocation type for
    the global data.

 4) And last but not least in the actual relocation step in
    bpf_program__relocate(), we mark the ldimm64 instruction
    with src_reg = BPF_PSEUDO_MAP_VALUE where in the first
    imm field the map's file descriptor is stored as similarly
    done as in BPF_PSEUDO_MAP_FD, and in the second imm field
    (as ldimm64 is 2-insn wide) we store the access offset
    into the section. Given these maps have only single element
    ldimm64's off remains zero in both parts.

 5) On kernel side, this special marked BPF_PSEUDO_MAP_VALUE
    load will then store the actual target address in order
    to have a 'map-lookup'-free access. That is, the actual
    map value base address + offset. The destination register
    in the verifier will then be marked as PTR_TO_MAP_VALUE,
    containing the fixed offset as reg->off and backing BPF
    map as reg->map_ptr. Meaning, it's treated as any other
    normal map value from verification side, only with
    efficient, direct value access instead of actual call to
    map lookup helper as in the typical case.

Currently, only support for static global variables has been
added, and libbpf rejects non-static global variables from
loading. This can be lifted until we have proper semantics
for how BPF will treat multi-object BPF loads. From BTF side,
libbpf will set the value type id of the types corresponding
to the ".bss", ".data" and ".rodata" names which LLVM will
emit without the object name prefix. The key type will be
left as zero, thus making use of the key-less BTF option in
array maps.

Simple example dump of program using globals vars in each
section:

  # bpftool prog
  [...]
  6784: sched_cls  name load_static_dat  tag a7e1291567277844  gpl
        loaded_at 2019-03-11T15:39:34+0000  uid 0
        xlated 1776B  jited 993B  memlock 4096B  map_ids 2238,2237,2235,2236,2239,2240

  # bpftool map show id 2237
  2237: array  name test_glo.bss  flags 0x0
        key 4B  value 64B  max_entries 1  memlock 4096B
  # bpftool map show id 2235
  2235: array  name test_glo.data  flags 0x0
        key 4B  value 64B  max_entries 1  memlock 4096B
  # bpftool map show id 2236
  2236: array  name test_glo.rodata  flags 0x80
        key 4B  value 96B  max_entries 1  memlock 4096B

  # bpftool prog dump xlated id 6784
  int load_static_data(struct __sk_buff * skb):
  ; int load_static_data(struct __sk_buff *skb)
     0: (b7) r6 = 0
  ; test_reloc(number, 0, &num0);
     1: (63) *(u32 *)(r10 -4) = r6
     2: (bf) r2 = r10
  ; int load_static_data(struct __sk_buff *skb)
     3: (07) r2 += -4
  ; test_reloc(number, 0, &num0);
     4: (18) r1 = map[id:2238]
     6: (18) r3 = map[id:2237][0]+0    <-- direct addr in .bss area
     8: (b7) r4 = 0
     9: (85) call array_map_update_elem#100464
    10: (b7) r1 = 1
  ; test_reloc(number, 1, &num1);
  [...]
  ; test_reloc(string, 2, str2);
   120: (18) r8 = map[id:2237][0]+16   <-- same here at offset +16
   122: (18) r1 = map[id:2239]
   124: (18) r3 = map[id:2237][0]+16
   126: (b7) r4 = 0
   127: (85) call array_map_update_elem#100464
   128: (b7) r1 = 120
  ; str1[5] = 'x';
   129: (73) *(u8 *)(r9 +5) = r1
  ; test_reloc(string, 3, str1);
   130: (b7) r1 = 3
   131: (63) *(u32 *)(r10 -4) = r1
   132: (b7) r9 = 3
   133: (bf) r2 = r10
  ; int load_static_data(struct __sk_buff *skb)
   134: (07) r2 += -4
  ; test_reloc(string, 3, str1);
   135: (18) r1 = map[id:2239]
   137: (18) r3 = map[id:2235][0]+16   <-- direct addr in .data area
   139: (b7) r4 = 0
   140: (85) call array_map_update_elem#100464
   141: (b7) r1 = 111
  ; __builtin_memcpy(&str2[2], "hello", sizeof("hello"));
   142: (73) *(u8 *)(r8 +6) = r1       <-- further access based on .bss data
   143: (b7) r1 = 108
   144: (73) *(u8 *)(r8 +5) = r1
  [...]

For Cilium use-case in particular, this enables migrating configuration
constants from Cilium daemon's generated header defines into global
data sections such that expensive runtime recompilations with LLVM can
be avoided altogether. Instead, the ELF file becomes effectively a
"template", meaning, it is compiled only once (!) and the Cilium daemon
will then rewrite relevant configuration data from the ELF's .data or
.rodata sections directly instead of recompiling the program. The
updated ELF is then loaded into the kernel and atomically replaces
the existing program in the networking datapath. More info in [0].

Based upon recent fix in LLVM, commit c0db6b6bd444 ("[BPF] Don't fail
for static variables").

  [0] LPC 2018, BPF track, "ELF relocation for static data in BPF",
      http://vger.kernel.org/lpc-bpf2018.html#session-3

Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2019-04-10 14:27:33 -07:00
Joe Stringer
a3d236332e bpf, libbpf: refactor relocation handling
Adjust the code for relocations slightly with no functional changes,
so that upcoming patches that will introduce support for relocations
into the .data, .rodata and .bss sections can be added independent
of these changes.

Signed-off-by: Joe Stringer <joe@wand.net.nz>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2019-04-10 14:27:33 -07:00
Andrey Ignatov
a6ce1c6423 libbpf: Ignore -Wformat-nonliteral warning
vsprintf() in __base_pr() uses nonliteral format string and it breaks
compilation for those who provide corresponding extra CFLAGS, e.g.:
https://github.com/libbpf/libbpf/issues/27

If libbpf is built with the flags from PR:

  libbpf.c:68:26: error: format string is not a string literal
  [-Werror,-Wformat-nonliteral]
          return vfprintf(stderr, format, args);
                                  ^~~~~~
  1 error generated.

Ignore this warning since the use case in libbpf.c is legit.

Signed-off-by: Andrey Ignatov <rdna@fb.com>
Acked-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2019-04-10 14:27:33 -07:00
Alexei Starovoitov
6d7acdae6d libbpf: teach libbpf about log_level bit 2
Allow bpf_prog_load_xattr() to specify log_level for program loading.

Teach libbpf to accept log_level with bit 2 set.

Increase default BPF_LOG_BUF_SIZE from 256k to 16M.
There is no downside to increase it to a maximum allowed by old kernels.
Existing 256k limit caused ENOSPC errors and users were not able to see
verifier error which is printed at the end of the verifier log.

If ENOSPC is hit, double the verifier log and try again to capture
the verifier error.

Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2019-04-10 14:27:33 -07:00
Song Liu
413703c8cb tools lib bpf: Introduce bpf_program__get_prog_info_linear()
Currently, bpf_prog_info includes 9 arrays. The user has the option to
fetch any combination of these arrays. However, this requires a lot of
handling.

This work becomes more tricky when we need to store bpf_prog_info to a
file, because these arrays are allocated independently.

This patch introduces 'struct bpf_prog_info_linear', which stores arrays
of bpf_prog_info in continuous memory.

Helper functions are introduced to unify the work to get different sets
of bpf_prog_info.  Specifically, bpf_program__get_prog_info_linear()
allows the user to select which arrays to fetch, and handles details for
the user.

Please see the comments right before 'enum bpf_prog_info_array' for more
details and examples.

Signed-off-by: Song Liu <songliubraving@fb.com>
Reviewed-by: Jiri Olsa <jolsa@kernel.org>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lkml.kernel.org/r/ce92c091-e80d-a0c1-4aa0-987706c42b20@iogearbox.net
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: kernel-team@fb.com
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stanislav Fomichev <sdf@google.com>
Link: http://lkml.kernel.org/r/20190312053051.2690567-3-songliubraving@fb.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2019-03-28 19:51:55 -07:00
Changbin Du
556285a37a perf tools: Fix errors under optimization level '-Og'
Optimization level '-Og' offers a reasonable level of optimization while
maintaining fast compilation and a good debugging experience. This patch
tries to make it work.

  $ make DEBUG=1 EXTRA_CFLAGS='-Og'
  bench/epoll-ctl.c: In function ‘do_threads’:
  bench/epoll-ctl.c:274:9: error: ‘ret’ may be used uninitialized in this function [-Werror=maybe-uninitialized]
    return ret;
           ^~~
  ...

Signed-off-by: Changbin Du <changbin.du@gmail.com>
Reviewed-by: Jiri Olsa <jolsa@kernel.org>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt (VMware) <rostedt@goodmis.org>
Link: http://lkml.kernel.org/r/20190316080556.3075-4-changbin.du@gmail.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2019-03-28 19:51:55 -07:00
Andrii Nakryiko
c4af4fcac5 libbpf: handle BTF parsing and loading properly
This patch splits and cleans up error handling logic for loading BTF data.
Previously, if BTF data was parsed successfully, but failed to load into
kernel, we'd report nonsensical error code, instead of error returned from
btf__load(). Now btf__new() and btf__load() are handled separately with proper
cleanup and warning reporting.

Fixes: d29d87f7e612 ("btf: separate btf creation and loading")
Reported-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Acked-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2019-03-19 12:17:19 -07:00
Nikita V. Shirokov
a5831bef6d bpf, libbpf: fixing leak when kernel does not support btf
We could end up in situation when we have object file w/ all btf
info, but kernel does not support btf yet. In this situation
currently libbpf just set obj->btf to NULL w/o freeing it first.
This patch is fixing it by making sure to run btf__free first.

Fixes: d29d87f7e612 ("btf: separate btf creation and loading")
Signed-off-by: Nikita V. Shirokov <tehnerd@tehnerd.com>
Acked-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2019-03-19 12:17:19 -07:00
Jakub Kicinski
14fc408f9d tools: libbpf: add a correctly named define for map iteration
For historical reasons the helper to loop over maps in an object
is called bpf_map__for_each while it really should be called
bpf_object__for_each_map.  Rename and add a correctly named
define for backward compatibility.

Switch all in-tree users to the correct name (Quentin).

Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: Quentin Monnet <quentin.monnet@netronome.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2019-03-02 21:31:13 -08:00
Yonghong Song
5beb8a2ebf sync with latest bpf-next
Signed-off-by: Yonghong Song <yhs@fb.com>
2019-02-15 08:50:10 -08:00
Andrii Nakryiko
6f9a833985 sync with latest bpf-next (#11)
Sync latest libbpf sources. Tested against pahole.

Signed-off-by: Andrii Nakryiko <andriin@fb.com>
2019-02-15 07:38:45 -08:00
yonghong-song
f0bcba631d sync with latest bpf-next (#10)
sync with latest bpf-next. tested with fb internal testcase and bcc.

Signed-off-by: Yonghong Song <yhs@fb.com>
2019-02-07 21:58:07 -08:00
Yonghong Song
b19c6dcf62 sync with bpf-next
Sync with the following bug fix:
  commit a8a1f7d09cfc7e18874786c7634c9e71384fcd4e (HEAD -> bpf-next2, bpf-next/master)
  Author: Stanislav Fomichev <sdf@google.com>
  Date:   Mon Feb 4 16:20:55 2019 -0800

    libbpf: fix libbpf_print

    With the recent print rework we now have the following problem:
    pr_{warning,info,debug} expand to __pr which calls libbpf_print.
    libbpf_print does va_start and calls __libbpf_pr with va_list argument.
    In __base_pr we again do va_start. Because the next argument is a
    va_list, we don't get correct pointer to the argument (and print noting
    in my case, I don't know why it doesn't crash tbh).

    ......

    Signed-off-by: Stanislav Fomichev <sdf@google.com>

Signed-off-by: Yonghong Song <yhs@fb.com>
2019-02-04 19:42:31 -08:00
Yonghong Song
1dc0296fce sync with latest bpf-next
The following three files are added:
  libbpf_probes.c
  libbpf_util.h
  libbpf.map

Signed-off-by: Yonghong Song <yhs@fb.com>
2019-02-04 13:29:57 -08:00
yonghong-song
07a48dcda2 sync with latest bpf-next (#6)
The following two new files are added:
  README.rst
  bpf_prog_linfo.c

Signed-off-by: Yonghong Song <yhs@fb.com>
2019-01-03 12:44:33 -08:00
yonghong-song
556e0a0def bpf: sync with latest bpf-next tree (#5)
sync with latest bpf-next tree.
the include/linux/filter.h is created as libbpf.c tries
to use various insn define macros.

Signed-off-by: Yonghong Song <yhs@fb.com>
2018-11-26 14:32:21 -08:00
Andrey Ignatov
62706e5557 Symbols visibility (#3)
* Sync from bpf-next

Sync the following commits from bpf-next:
commit ab9e08482122 ("libbpf: Per-symbol visibility for DSO")
commit c034a177d3c8 ("bpf: bpftool, add flag to allow non-compat map definitions")

Signed-off-by: Andrey Ignatov <rdna@fb.com>

* Use -fvisibility=hidden by default for DSO

This is Makefile part of:
commit ab9e08482122 ("libbpf: Per-symbol visibility for DSO")

See original commit for details.
2018-10-16 17:24:08 -07:00
Yonghong Song
66684189f0 initial commit
This initial commit added the following files
from bpf-next repository:
  src:
    <files from linux:tools/lib/bpf>
    bpf.c bpf.h btf.c btf.h libbpf.c libbpf.h
    libbpf_errno.c netlink.c nlattr.c nlattr.h
    str_error.c str_error.h
  include:
    <files from linux:tools/include/uapi/linux>
    uapi/linux/{bpf.h, btf.h}

    <files from linux:tools/include/tools>
    tools/libc_compat.h

The following files are also added:
  include/linux/{err.h, kernel.h, list.h, overflow.h, types.h}
These files are customized headers to satisfy compilation.
Their original counterparts are at linux:tools/include/linux
directory.

Signed-off-by: Yonghong Song <yhs@fb.com>
2018-10-09 21:56:40 -07:00