Make skip_mods_and_typedefs(), btf_kind_str(), and btf_func_linkage() helpers
available outside of libbpf.c, to be used by static linker code.
Also do few cleanups (error code fixes, comment clean up, etc) that don't
deserve their own commit.
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20210423181348.1801389-9-andrii@kernel.org
Factor out logic for sanity checking SHT_SYMTAB and SHT_REL sections into
separate sections. They are already quite extensive and are suffering from too
deep indentation. Subsequent changes will extend SYMTAB sanity checking
further, so it's better to factor each into a separate function.
No functional changes are intended.
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20210423181348.1801389-8-andrii@kernel.org
Refactor BTF-defined maps parsing logic to allow it to be nicely reused by BPF
static linker. Further, at least for BPF static linker, it's important to know
which attributes of a BPF map were defined explicitly, so provide a bit set
for each known portion of BTF map definition. This allows BPF static linker to
do a simple check when dealing with extern map declarations.
The same capabilities allow to distinguish attributes explicitly set to zero
(e.g., __uint(max_entries, 0)) vs the case of not specifying it at all (no
max_entries attribute at all). Libbpf is currently not utilizing that, but it
could be useful for backwards compatibility reasons later.
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20210423181348.1801389-7-andrii@kernel.org
Currently libbpf is very strict about parsing BPF program instruction
sections. No gaps are allowed between sequential BPF programs within a given
ELF section. Libbpf enforced that by keeping track of the next section offset
that should start a new BPF (sub)program and cross-checks that by searching
for a corresponding STT_FUNC ELF symbol.
But this is too restrictive once we allow to have weak BPF programs and link
together two or more BPF object files. In such case, some weak BPF programs
might be "overridden" by either non-weak BPF program with the same name and
signature, or even by another weak BPF program that just happened to be linked
first. That, in turn, leaves BPF instructions of the "lost" BPF (sub)program
intact, but there is no corresponding ELF symbol, because no one is going to
be referencing it.
Libbpf already correctly handles such cases in the sense that it won't append
such dead code to actual BPF programs loaded into kernel. So the only change
that needs to be done is to relax the logic of parsing BPF instruction
sections. Instead of assuming next BPF (sub)program section offset, iterate
available STT_FUNC ELF symbols to discover all available BPF subprograms and
programs.
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20210423181348.1801389-6-andrii@kernel.org
Define __hidden helper macro in bpf_helpers.h, which is a short-hand for
__attribute__((visibility("hidden"))). Add libbpf support to mark BPF
subprograms marked with __hidden as static in BTF information to enforce BPF
verifier's static function validation algorithm, which takes more information
(caller's context) into account during a subprogram validation.
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20210423181348.1801389-5-andrii@kernel.org
When used on externs SEC() macro will trigger compilation warning about
inapplicable `__attribute__((used))`. That's expected for extern declarations,
so suppress it with the corresponding _Pragma.
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20210423181348.1801389-4-andrii@kernel.org
Similarly to BPF_SEQ_PRINTF, this macro turns variadic arguments into an
array of u64, making it more natural to call the bpf_snprintf helper.
Signed-off-by: Florent Revest <revest@chromium.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20210419155243.1632274-6-revest@chromium.org
When initializing the __param array with a one liner, if all args are
const, the initial array value will be placed in the rodata section but
because libbpf does not support relocation in the rodata section, any
pointer in this array will stay NULL.
Fixes: c09add2fbc ("tools/libbpf: Add bpf_iter support")
Signed-off-by: Florent Revest <revest@chromium.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20210419155243.1632274-5-revest@chromium.org
drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
- keep the ZC code, drop the code related to reinit
net/bridge/netfilter/ebtables.c
- fix build after move to net_generic
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Conflicts:
MAINTAINERS
- keep Chandrasekar
drivers/net/ethernet/mellanox/mlx5/core/en_main.c
- simple fix + trust the code re-added to param.c in -next is fine
include/linux/bpf.h
- trivial
include/linux/ethtool.h
- trivial, fix kdoc while at it
include/linux/skmsg.h
- move to relevant place in tcp.c, comment re-wrapped
net/core/skmsg.c
- add the sk = sk // sk = NULL around calls
net/tipc/crypto.c
- trivial
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
The API gives access to inner map for map in map types (array or
hash of map). It will be used to dynamically set max_entries in it.
Signed-off-by: Yauheni Kaliuta <yauheni.kaliuta@redhat.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20210408061310.95877-7-yauheni.kaliuta@redhat.com
Prior to this commit xsk_socket__create(_shared) always attempted to create
the rx and tx rings for the socket. However this causes an issue when the
socket being setup is that which shares the fd with the UMEM. If a
previous call to this function failed with this socket after the rings were
set up, a subsequent call would always fail because the rings are not torn
down after the first call and when we try to set them up again we encounter
an error because they already exist. Solve this by remembering whether the
rings were set up by introducing new bools to struct xsk_umem which
represent the ring setup status and using them to determine whether or
not to set up the rings.
Fixes: 1cad078842 ("libbpf: add support for using AF_XDP sockets")
Signed-off-by: Ciara Loftus <ciara.loftus@intel.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20210331061218.1647-4-ciara.loftus@intel.com
If the call to xsk_socket__create fails, the user may want to retry the
socket creation using the same umem. Ensure that the umem is in the
same state on exit if the call fails by:
1. ensuring the umem _save pointers are unmodified.
2. not unmapping the set of umem rings that were set up with the umem
during xsk_umem__create, since those maps existed before the call to
xsk_socket__create and should remain in tact even in the event of
failure.
Fixes: 2f6324a393 ("libbpf: Support shared umems between queues and devices")
Signed-off-by: Ciara Loftus <ciara.loftus@intel.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20210331061218.1647-3-ciara.loftus@intel.com
Calls to xsk_socket__create dereference the umem to access the
fill_save and comp_save pointers. Make sure the umem is non-NULL
before doing this.
Fixes: 2f6324a393 ("libbpf: Support shared umems between queues and devices")
Signed-off-by: Ciara Loftus <ciara.loftus@intel.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Magnus Karlsson <magnus.karlsson@intel.com>
Link: https://lore.kernel.org/bpf/20210331061218.1647-2-ciara.loftus@intel.com
Currently, if there are multiple xdpsock instances running on a single
interface and in case one of the instances is terminated, the rest of
them are left in an inoperable state due to the fact of unloaded XDP
prog from interface.
Consider the scenario below:
// load xdp prog and xskmap and add entry to xskmap at idx 10
$ sudo ./xdpsock -i ens801f0 -t -q 10
// add entry to xskmap at idx 11
$ sudo ./xdpsock -i ens801f0 -t -q 11
terminate one of the processes and another one is unable to work due to
the fact that the XDP prog was unloaded from interface.
To address that, step away from setting bpf prog in favour of bpf_link.
This means that refcounting of BPF resources will be done automatically
by bpf_link itself.
Provide backward compatibility by checking if underlying system is
bpf_link capable. Do this by looking up/creating bpf_link on loopback
device. If it failed in any way, stick with netlink-based XDP prog.
therwise, use bpf_link-based logic.
When setting up BPF resources during xsk socket creation, check whether
bpf_link for a given ifindex already exists via set of calls to
bpf_link_get_next_id -> bpf_link_get_fd_by_id -> bpf_obj_get_info_by_fd
and comparing the ifindexes from bpf_link and xsk socket.
For case where resources exist but they are not AF_XDP related, bail out
and ask user to remove existing prog and then retry.
Lastly, do a bit of refactoring within __xsk_setup_xdp_prog and pull out
existing code branches based on prog_id value onto separate functions
that are responsible for resource initialization if prog_id was 0 and
for lookup existing resources for non-zero prog_id as that implies that
XDP program is present on the underlying net device. This in turn makes
it easier to follow, especially the teardown part of both branches.
Signed-off-by: Maciej Fijalkowski <maciej.fijalkowski@intel.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20210329224316.17793-7-maciej.fijalkowski@intel.com
This patch is to make libbpf able to handle the following extern
kernel function declaration and do the needed relocations before
loading the bpf program to the kernel.
extern int foo(struct sock *) __attribute__((section(".ksyms")))
In the collect extern phase, needed changes is made to
bpf_object__collect_externs() and find_extern_btf_id() to collect
extern function in ".ksyms" section. The func in the BTF datasec also
needs to be replaced by an int var. The idea is similar to the existing
handling in extern var. In case the BTF may not have a var, a dummy ksym
var is added at the beginning of bpf_object__collect_externs()
if there is func under ksyms datasec. It will also change the
func linkage from extern to global which the kernel can support.
It also assigns a param name if it does not have one.
In the collect relo phase, it will record the kernel function
call as RELO_EXTERN_FUNC.
bpf_object__resolve_ksym_func_btf_id() is added to find the func
btf_id of the running kernel.
During actual relocation, it will patch the BPF_CALL instruction with
src_reg = BPF_PSEUDO_FUNC_CALL and insn->imm set to the running
kernel func's btf_id.
The required LLVM patch: https://reviews.llvm.org/D93563
Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20210325015234.1548923-1-kafai@fb.com
This patch records the extern sym relocs first before recording
subprog relocs. The later patch will have relocs for extern
kernel function call which is also using BPF_JMP | BPF_CALL.
It will be easier to handle the extern symbols first in
the later patch.
is_call_insn() helper is added. The existing is_ldimm64() helper
is renamed to is_ldimm64_insn() for consistency.
Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20210325015227.1548623-1-kafai@fb.com
This patch renames RELO_EXTERN to RELO_EXTERN_VAR.
It is to avoid the confusion with a later patch adding
RELO_EXTERN_FUNC.
Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20210325015221.1547722-1-kafai@fb.com
This patch refactors code, that finds kernel btf_id by kind
and symbol name, to a new function find_ksym_btf_id().
It also adds a new helper __btf_kind_str() to return
a string by the numeric kind value.
Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20210325015214.1547069-1-kafai@fb.com
This patch refactors most of the logic from
bpf_object__resolve_ksyms_btf_id() into a new function
bpf_object__resolve_ksym_var_btf_id().
It is to get ready for a later patch adding
bpf_object__resolve_ksym_func_btf_id() which resolves
a kernel function to the running kernel btf_id.
Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20210325015207.1546749-1-kafai@fb.com
Ensure that BPF static linker preserves all DATASEC BTF types, even if some of
them might not have any variable information at all. This may happen if the
compiler promotes local initialized variable contents into .rodata section and
there are no global or static functions in the program.
For example,
$ cat t.c
struct t { char a; char b; char c; };
void bar(struct t*);
void find() {
struct t tmp = {1, 2, 3};
bar(&tmp);
}
$ clang -target bpf -O2 -g -S t.c
.long 104 # BTF_KIND_DATASEC(id = 8)
.long 251658240 # 0xf000000
.long 0
.ascii ".rodata" # string offset=104
$ clang -target bpf -O2 -g -c t.c
$ readelf -S t.o | grep data
[ 4] .rodata PROGBITS 0000000000000000 00000090
Fixes: 8fd27bf69b ("libbpf: Add BPF static linker BTF and BTF.ext support")
Reported-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20210326043036.3081011-1-andrii@kernel.org
The current code bails out with negative and positive returns.
If the callback returns a positive return code, 'ring_buffer__consume()'
and 'ring_buffer__poll()' will return a spurious number of records
consumed, but mostly important will continue the processing loop.
This patch makes positive returns from the callback a no-op.
Fixes: bf99c936f9 ("libbpf: Add BPF ring buffer support")
Signed-off-by: Pedro Tammela <pctammela@mojatatu.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20210325150115.138750-1-pctammela@mojatatu.com
Unfortunately some distros don't have their kernel version defined
accurately in <linux/version.h> due to different long term support
reasons.
It is important to have a way to override the bpf kern_version
attribute during runtime: some old kernels might still check for
kern_version attribute during bpf_prog_load().
Signed-off-by: Rafael David Tinoco <rafaeldtinoco@ubuntu.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Link: https://lore.kernel.org/bpf/20210323040952.2118241-1-rafaeldtinoco@ubuntu.com
bpf_program__get_type() and bpf_program__get_expected_attach_type() shouldn't
modify given bpf_program, so mark input parameter as const struct bpf_program.
This eliminates unnecessary compilation warnings or explicit casts in user
programs.
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20210324172941.2609884-1-andrii@kernel.org
Alexei Starovoitov says:
====================
pull-request: bpf-next 2021-03-24
The following pull-request contains BPF updates for your *net-next* tree.
We've added 37 non-merge commits during the last 15 day(s) which contain
a total of 65 files changed, 3200 insertions(+), 738 deletions(-).
The main changes are:
1) Static linking of multiple BPF ELF files, from Andrii.
2) Move drop error path to devmap for XDP_REDIRECT, from Lorenzo.
3) Spelling fixes from various folks.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>
The vmlinux.h generated from BTF is invalid when building
drivers/phy/ti/phy-gmii-sel.c with clang:
vmlinux.h:61702:27: error: array type has incomplete element type ‘struct reg_field’
61702 | const struct reg_field (*regfields)[3];
| ^~~~~~~~~
bpftool generates a forward declaration for this struct regfield, which
compilers aren't happy about. Here's a simplified reproducer:
struct inner {
int val;
};
struct outer {
struct inner (*ptr_to_array)[2];
} A;
After build with clang -> bpftool btf dump c -> clang/gcc:
./def-clang.h:11:23: error: array has incomplete element type 'struct inner'
struct inner (*ptr_to_array)[2];
Member ptr_to_array of struct outer is a pointer to an array of struct
inner. In the DWARF generated by clang, struct outer appears before
struct inner, so when converting BTF of struct outer into C, bpftool
issues a forward declaration to struct inner. With GCC the DWARF info is
reversed so struct inner gets fully defined.
That forward declaration is not sufficient when compilers handle an
array of the struct, even when it's only used through a pointer. Note
that we can trigger the same issue with an intermediate typedef:
struct inner {
int val;
};
typedef struct inner inner2_t[2];
struct outer {
inner2_t *ptr_to_array;
} A;
Becomes:
struct inner;
typedef struct inner inner2_t[2];
And causes:
./def-clang.h:10:30: error: array has incomplete element type 'struct inner'
typedef struct inner inner2_t[2];
To fix this, clear through_ptr whenever we encounter an intermediate
array, to make the inner struct part of a strong link and force full
declaration.
Fixes: 351131b51c ("libbpf: add btf_dump API for BTF-to-C conversion")
Signed-off-by: Jean-Philippe Brucker <jean-philippe@linaro.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20210319112554.794552-2-jean-philippe@linaro.org
Similar to
https://lore.kernel.org/bpf/20210313210920.1959628-2-andrii@kernel.org/
When DECLARE_LIBBPF_OPTS is used with inline field initialization, e.g:
DECLARE_LIBBPF_OPTS(btf_dump_emit_type_decl_opts, opts,
.field_name = var_ident,
.indent_level = 2,
.strip_mods = strip_mods,
);
and compiled in debug mode, the compiler generates code which
leaves the padding uninitialized and triggers errors within libbpf APIs
which require strict zero initialization of OPTS structs.
Adding anonymous padding field fixes the issue.
Fixes: 9f81654eeb ("libbpf: Expose BTF-to-C type declaration emitting API")
Suggested-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: KP Singh <kpsingh@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20210319192117.2310658-1-kpsingh@kernel.org
Add .BTF and .BTF.ext static linking logic.
When multiple BPF object files are linked together, their respective .BTF and
.BTF.ext sections are merged together. BTF types are not just concatenated,
but also deduplicated. .BTF.ext data is grouped by type (func info, line info,
core_relos) and target section names, and then all the records are
concatenated together, preserving their relative order. All the BTF type ID
references and string offsets are updated as necessary, to take into account
possibly deduplicated strings and types.
BTF DATASEC types are handled specially. Their respective var_secinfos are
accumulated separately in special per-section data and then final DATASEC
types are emitted at the very end during bpf_linker__finalize() operation,
just before emitting final ELF output file.
BTF data can also provide "section annotations" for some extern variables.
Such concept is missing in ELF, but BTF will have DATASEC types for such
special extern datasections (e.g., .kconfig, .ksyms). Such sections are called
"ephemeral" internally. Internally linker will keep metadata for each such
section, collecting variables information, but those sections won't be emitted
into the final ELF file.
Also, given LLVM/Clang during compilation emits BTF DATASECS that are
incomplete, missing section size and variable offsets for static variables,
BPF static linker will initially fix up such DATASECs, using ELF symbols data.
The final DATASECs will preserve section sizes and all variable offsets. This
is handled correctly by libbpf already, so won't cause any new issues. On the
other hand, it's actually a nice property to have a complete BTF data without
runtime adjustments done during bpf_object__open() by libbpf. In that sense,
BPF static linker is also a BTF normalizer.
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20210318194036.3521577-8-andrii@kernel.org
Introduce BPF static linker APIs to libbpf. BPF static linker allows to
perform static linking of multiple BPF object files into a single combined
resulting object file, preserving all the BPF programs, maps, global
variables, etc.
Data sections (.bss, .data, .rodata, .maps, maps, etc) with the same name are
concatenated together. Similarly, code sections are also concatenated. All the
symbols and ELF relocations are also concatenated in their respective ELF
sections and are adjusted accordingly to the new object file layout.
Static variables and functions are handled correctly as well, adjusting BPF
instructions offsets to reflect new variable/function offset within the
combined ELF section. Such relocations are referencing STT_SECTION symbols and
that stays intact.
Data sections in different files can have different alignment requirements, so
that is taken care of as well, adjusting sizes and offsets as necessary to
satisfy both old and new alignment requirements.
DWARF data sections are stripped out, currently. As well as LLLVM_ADDRSIG
section, which is ignored by libbpf in bpf_object__open() anyways. So, in
a way, BPF static linker is an analogue to `llvm-strip -g`, which is a pretty
nice property, especially if resulting .o file is then used to generate BPF
skeleton.
Original string sections are ignored and instead we construct our own set of
unique strings using libbpf-internal `struct strset` API.
To reduce the size of the patch, all the .BTF and .BTF.ext processing was
moved into a separate patch.
The high-level API consists of just 4 functions:
- bpf_linker__new() creates an instance of BPF static linker. It accepts
output filename and (currently empty) options struct;
- bpf_linker__add_file() takes input filename and appends it to the already
processed ELF data; it can be called multiple times, one for each BPF
ELF object file that needs to be linked in;
- bpf_linker__finalize() needs to be called to dump final ELF contents into
the output file, specified when bpf_linker was created; after
bpf_linker__finalize() is called, no more bpf_linker__add_file() and
bpf_linker__finalize() calls are allowed, they will return error;
- regardless of whether bpf_linker__finalize() was called or not,
bpf_linker__free() will free up all the used resources.
Currently, BPF static linker doesn't resolve cross-object file references
(extern variables and/or functions). This will be added in the follow up patch
set.
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20210318194036.3521577-7-andrii@kernel.org
Add btf__add_type() API that performs shallow copy of a given BTF type from
the source BTF into the destination BTF. All the information and type IDs are
preserved, but all the strings encountered are added into the destination BTF
and corresponding offsets are rewritten. BTF type IDs are assumed to be
correct or such that will be (somehow) modified afterwards.
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20210318194036.3521577-6-andrii@kernel.org
Extract BTF logic for maintaining a set of strings data structure, used for
BTF strings section construction in writable mode, into separate re-usable
API. This data structure is going to be used by bpf_linker to maintains ELF
STRTAB section, which has the same layout as BTF strings section.
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/20210318194036.3521577-5-andrii@kernel.org
Rename btf_add_mem() and btf_ensure_mem() helpers that abstract away details
of dynamically resizable memory to use libbpf_ prefix, as they are not
BTF-specific. No functional changes.
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20210318194036.3521577-4-andrii@kernel.org
Extract and generalize the logic to iterate BTF type ID and string offset
fields within BTF types and .BTF.ext data. Expose this internally in libbpf
for re-use by bpf_linker.
Additionally, complete strings deduplication handling for BTF.ext (e.g., CO-RE
access strings), which was previously missing. There previously was no
case of deduplicating .BTF.ext data, but bpf_linker is going to use it.
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20210318194036.3521577-3-andrii@kernel.org
btf_type_by_id() is internal-only convenience API returning non-const pointer
to struct btf_type. Expose it outside of btf.c for re-use.
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20210318194036.3521577-2-andrii@kernel.org
Given that vmlinux.h is not compatible with headers like stddef.h, NULL poses
an annoying problem: it is defined as #define, so is not captured in BTF, so
is not emitted into vmlinux.h. This leads to users either sticking to explicit
0, or defining their own NULL (as progs/skb_pkt_end.c does).
But it's easy for bpf_helpers.h to provide (conditionally) NULL definition.
Similarly, KERNEL_VERSION is another commonly missed macro that came up
multiple times. So this patch adds both of them, along with offsetof(), that
also is typically defined in stddef.h, just like NULL.
This might cause compilation warning for existing BPF applications defining
their own NULL and/or KERNEL_VERSION already:
progs/skb_pkt_end.c:7:9: warning: 'NULL' macro redefined [-Wmacro-redefined]
#define NULL 0
^
/tmp/linux/tools/testing/selftests/bpf/tools/include/vmlinux.h:4:9: note: previous definition is here
#define NULL ((void *)0)
^
It is trivial to fix, though, so long-term benefits outweight temporary
inconveniences.
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20210317200510.1354627-2-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Otherwise, there exists a small window between the opening and closing
of the socket fd where it may leak into processes launched by some other
thread.
Fixes: 949abbe884 ("libbpf: add function to setup XDP")
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Toke Høiland-Jørgensen <toke@redhat.com>
Link: https://lore.kernel.org/bpf/20210317115857.6536-1-memxor@gmail.com
When it failed to get section names, it should call into
bpf_object__elf_finish() like others.
Fixes: 88a8212028 ("libbpf: Factor out common ELF operations and improve logging")
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20210317145414.884817-1-namhyung@kernel.org
Adding such anonymous padding fixes the issue with uninitialized portions of
bpf_xdp_set_link_opts when using LIBBPF_DECLARE_OPTS macro with inline field
initialization:
DECLARE_LIBBPF_OPTS(bpf_xdp_set_link_opts, opts, .old_fd = -1);
When such code is compiled in debug mode, compiler is generating code that
leaves padding bytes uninitialized, which triggers error inside libbpf APIs
that do strict zero initialization checks for OPTS structs.
Adding anonymous padding field fixes the issue.
Fixes: bd5ca3ef93 ("libbpf: Add function to set link XDP fd while specifying old program")
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20210313210920.1959628-2-andrii@kernel.org
Linux headers might pull 'linux/stddef.h' which defines
'__always_inline' as the following:
#ifndef __always_inline
#define __always_inline inline
#endif
This becomes an issue if the program picks up the 'linux/stddef.h'
definition as the macro now just hints inline to clang.
This change now enforces the proper definition for BPF programs
regardless of the include order.
Signed-off-by: Pedro Tammela <pctammela@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20210314173839.457768-1-pctammela@gmail.com
The only user of libbpf_util.h is xsk.h. Move the barriers to xsk.h,
and remove libbpf_util.h. The barriers are used as an implementation
detail, and should not be considered part of the stable API.
Signed-off-by: Björn Töpel <bjorn.topel@intel.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20210310080929.641212-3-bjorn.topel@gmail.com
In commit 291471dd15 ("libbpf, xsk: Add libbpf_smp_store_release
libbpf_smp_load_acquire") linux/compiler.h was added as a dependency
to xsk.h, which is the user-facing API. This makes it harder for
userspace application to consume the library. Here the header
inclusion is removed, and instead {READ,WRITE}_ONCE() is added
explicitly.
Signed-off-by: Björn Töpel <bjorn.topel@intel.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20210310080929.641212-2-bjorn.topel@gmail.com
Alexei Starovoitov says:
====================
pull-request: bpf-next 2021-03-09
The following pull-request contains BPF updates for your *net-next* tree.
We've added 90 non-merge commits during the last 17 day(s) which contain
a total of 114 files changed, 5158 insertions(+), 1288 deletions(-).
The main changes are:
1) Faster bpf_redirect_map(), from Björn.
2) skmsg cleanup, from Cong.
3) Support for floating point types in BTF, from Ilya.
4) Documentation for sys_bpf commands, from Joe.
5) Support for sk_lookup in bpf_prog_test_run, form Lorenz.
6) Enable task local storage for tracing programs, from Song.
7) bpf_for_each_map_elem() helper, from Yonghong.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>
It was reported ([0]) that having optional -m flag between source and
destination arguments in install command breaks bpftools cross-build
on MacOS. Move -m to the front to fix this issue.
[0] https://github.com/openwrt/openwrt/pull/3959
Fixes: 7110d80d53 ("libbpf: Makefile set specified permission mode")
Signed-off-by: Georgi Valkov <gvalkov@abv.bg>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20210308183038.613432-1-andrii@kernel.org
Now that the AF_XDP rings have load-acquire/store-release semantics,
move libbpf to that as well.
The library-internal libbpf_smp_{load_acquire,store_release} are only
valid for 32-bit words on ARM64.
Also, remove the barriers that are no longer in use.
Signed-off-by: Björn Töpel <bjorn.topel@intel.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Toke Høiland-Jørgensen <toke@redhat.com>
Link: https://lore.kernel.org/bpf/20210305094113.413544-3-bjorn.topel@gmail.com
Abstract out the target parameter so that upcoming commits, more than
just the existing "helpers" target can be called to generate specific
portions of docs from the eBPF UAPI headers.
Signed-off-by: Joe Stringer <joe@cilium.io>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Reviewed-by: Quentin Monnet <quentin@isovalent.com>
Acked-by: Toke Høiland-Jørgensen <toke@redhat.com>
Link: https://lore.kernel.org/bpf/20210302171947.2268128-10-joe@cilium.io
The logic follows that of BTF_KIND_INT most of the time. Sanitization
replaces BTF_KIND_FLOATs with equally-sized empty BTF_KIND_STRUCTs on
older kernels, for example, the following:
[4] FLOAT 'float' size=4
becomes the following:
[4] STRUCT '(anon)' size=4 vlen=0
With dwarves patch [1] and this patch, the older kernels, which were
failing with the floating-point-related errors, will now start working
correctly.
[1] https://github.com/iii-i/dwarves/commit/btf-kind-float-v2
Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20210226202256.116518-4-iii@linux.ibm.com
xsk_lookup_bpf_maps, based on prog_fd, looks whether current prog has a
reference to XSKMAP. BPF prog can include insns that work on various BPF
maps and this is covered by iterating through map_ids.
The bpf_map_info that is passed to bpf_obj_get_info_by_fd for filling
needs to be cleared at each iteration, so that it doesn't contain any
outdated fields and that is currently missing in the function of
interest.
To fix that, zero-init map_info via memset before each
bpf_obj_get_info_by_fd call.
Also, since the area of this code is touched, in general strcmp is
considered harmful, so let's convert it to strncmp and provide the
size of the array name for current map_info.
While at it, do s/continue/break/ once we have found the xsks_map to
terminate the search.
Fixes: 5750902a6e ("libbpf: proper XSKMAP cleanup")
Signed-off-by: Maciej Fijalkowski <maciej.fijalkowski@intel.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Björn Töpel <bjorn.topel@intel.com>
Link: https://lore.kernel.org/bpf/20210303185636.18070-4-maciej.fijalkowski@intel.com
A new relocation RELO_SUBPROG_ADDR is added to capture
subprog addresses loaded with ld_imm64 insns. Such ld_imm64
insns are marked with BPF_PSEUDO_FUNC and will be passed to
kernel. For bpf_for_each_map_elem() case, kernel will
check that the to-be-used subprog address must be a static
function and replace it with proper actual jited func address.
Signed-off-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20210226204930.3885367-1-yhs@fb.com
Move function is_ldimm64() close to the beginning of libbpf.c,
so it can be reused by later code and the next patch as well.
There is no functionality change.
Signed-off-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20210226204929.3885295-1-yhs@fb.com
When libbpf initializes the kernel's struct_ops in
"bpf_map__init_kern_struct_ops()", it enforces all
pointer types must be a function pointer and rejects
others. It turns out to be too strict. For example,
when directly using "struct tcp_congestion_ops" from vmlinux.h,
it has a "struct module *owner" member and it is set to NULL
in a bpf_tcp_cc.o.
Instead, it only needs to ensure the member is a function
pointer if it has been set (relocated) to a bpf-prog.
This patch moves the "btf_is_func_proto(kern_mtype)" check
after the existing "if (!prog) { continue; }". The original debug
message in "if (!prog) { continue; }" is also removed since it is
no longer valid. Beside, there is a later debug message to tell
which function pointer is set.
The "btf_is_func_proto(mtype)" has already been guaranteed
in "bpf_object__collect_st_ops_relos()" which has been run
before "bpf_map__init_kern_struct_ops()". Thus, this check
is removed.
v2:
- Remove outdated debug message (Andrii)
Remove because there is a later debug message to tell
which function pointer is set.
- Following mtype->type is no longer needed. Remove:
"skip_mods_and_typedefs(btf, mtype->type, &mtype_id)"
- Do "if (!prog)" test before skip_mods_and_typedefs.
Fixes: 590a008882 ("bpf: libbpf: Add STRUCT_OPS support")
Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20210212021030.266932-1-kafai@fb.com
We have the environments where usage of AF_INET is prohibited
(cgroup/sock_create returns EPERM for AF_INET). Let's use
AF_LOCAL instead of AF_INET, it should perfectly work with SIOCETHTOOL.
Signed-off-by: Stanislav Fomichev <sdf@google.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Tested-by: Björn Töpel <bjorn.topel@intel.com>
Acked-by: Björn Töpel <bjorn.topel@intel.com>
Link: https://lore.kernel.org/bpf/20210209221826.922940-1-sdf@google.com
Libbpf's Makefile relies on Linux tools infrastructure's feature detection
framework, but libbpf's needs are very modest: it detects the presence of
libelf and libz, both of which are mandatory. So it doesn't benefit much from
the framework, but pays significant costs in terms of maintainability and
debugging experience, when something goes wrong. The other feature detector,
testing for the presernce of minimal BPF API in system headers is long
obsolete as well, providing no value.
So stop using feature detection and just assume the presence of libelf and
libz during build time. Worst case, user will get a clear and actionable
linker error, e.g.:
/usr/bin/ld: cannot find -lelf
On the other hand, we completely bypass recurring issues various users
reported over time with false negatives of feature detection (libelf or libz
not being detected, while they are actually present in the system).
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Acked-by: Randy Dunlap <rdunlap@infradead.org>
Link: https://lore.kernel.org/bpf/20210203203445.3356114-1-andrii@kernel.org
Add detection for kernel version, and adapt the BPF program based on
kernel support. This way, users will get the best possible performance
from the BPF program.
Signed-off-by: Björn Töpel <bjorn.topel@intel.com>
Signed-off-by: Marek Majtyka <alardam@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Reviewed-by: Maciej Fijalkowski <maciej.fijalkowski@intel.com>
Acked-by: Maciej Fijalkowski <maciej.fijalkowski@intel.com>
Link: https://lore.kernel.org/bpf/20210122105351.11751-4-bjorn.topel@gmail.com
For very large ELF objects (with many sections), we could
get special value SHN_XINDEX (65535) for elf object's string
table index - e_shstrndx.
Call elf_getshdrstrndx to get the proper string table index,
instead of reading it directly from ELF header.
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20210121202203.9346-4-jolsa@kernel.org
Conflicts:
drivers/net/can/dev.c
commit 03f16c5075 ("can: dev: can_restart: fix use after free bug")
commit 3e77f70e73 ("can: dev: move driver related infrastructure into separate subdir")
Code move.
drivers/net/dsa/b53/b53_common.c
commit 8e4052c32d ("net: dsa: b53: fix an off by one in checking "vlan->vid"")
commit b7a9e0da2d ("net: switchdev: remove vid_begin -> vid_end range from VLAN objects")
Field rename.
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Add inline to __always_inline making it match the linux/compiler.h.
Adding this avoids an unused function warning on bpf_tail_call_static
when compining with -Wall.
Signed-off-by: Ian Rogers <irogers@google.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20210113223609.3358812-1-irogers@google.com
Add support for searching for ksym externs not just in vmlinux BTF, but across
all module BTFs, similarly to how it's done for CO-RE relocations. Kernels
that expose module BTFs through sysfs are assumed to support new ldimm64
instruction extension with BTF FD provided in insn[1].imm field, so no extra
feature detection is performed.
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Yonghong Song <yhs@fb.com>
Acked-by: Hao Luo <haoluo@google.com>
Link: https://lore.kernel.org/bpf/20210112075520.4103414-7-andrii@kernel.org
Empty BTFs do come up (e.g., simple kernel modules with no new types and
strings, compared to the vmlinux BTF) and there is nothing technically wrong
with them. So remove unnecessary check preventing loading empty BTFs.
Fixes: d812362450 ("libbpf: Fix BTF data layout checks and allow empty BTF")
Reported-by: Christopher William Snowhill <chris@kode54.net>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20210110070341.1380086-2-andrii@kernel.org
Add comments clarifying that USER variants of CO-RE reading macro are still
only going to work with kernel types, defined in kernel or kernel module BTF.
This should help preventing invalid use of those macro to read user-defined
types (which doesn't work with CO-RE).
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20210108194408.3468860-1-andrii@kernel.org
BPF_CORE_READ(), in addition to handling CO-RE relocations, also allows much
nicer way to read data structures with nested pointers. Instead of writing
a sequence of bpf_probe_read() calls to follow links, one can just write
BPF_CORE_READ(a, b, c, d) to effectively do a->b->c->d read. This is a welcome
ability when porting BCC code, which (in most cases) allows exactly the
intuitive a->b->c->d variant.
This patch adds non-CO-RE variants of BPF_CORE_READ() family of macros for
cases where CO-RE is not supported (e.g., old kernels). In such cases, the
property of shortening a sequence of bpf_probe_read()s to a simple
BPF_PROBE_READ(a, b, c, d) invocation is still desirable, especially when
porting BCC code to libbpf. Yet, no CO-RE relocation is going to be emitted.
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20201218235614.2284956-3-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Add BPF_CORE_READ_USER(), BPF_CORE_READ_USER_STR() and their _INTO()
variations to allow reading CO-RE-relocatable kernel data structures from the
user-space. One of such cases is reading input arguments of syscalls, while
reaping the benefits of CO-RE relocations w.r.t. handling 32/64 bit
conversions and handling missing/new fields in UAPI data structs.
Suggested-by: Gilad Reti <gilad.reti@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20201218235614.2284956-2-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Daniel Borkmann says:
====================
pull-request: bpf-next 2020-12-14
1) Expose bpf_sk_storage_*() helpers to iterator programs, from Florent Revest.
2) Add AF_XDP selftests based on veth devs to BPF selftests, from Weqaar Janjua.
3) Support for finding BTF based kernel attach targets through libbpf's
bpf_program__set_attach_target() API, from Andrii Nakryiko.
4) Permit pointers on stack for helper calls in the verifier, from Yonghong Song.
5) Fix overflows in hash map elem size after rlimit removal, from Eric Dumazet.
6) Get rid of direct invocation of llc in BPF selftests, from Andrew Delgadillo.
7) Fix xsk_recvmsg() to reorder socket state check before access, from Björn Töpel.
8) Add new libbpf API helper to retrieve ring buffer epoll fd, from Brendan Jackman.
9) Batch of minor BPF selftest improvements all over the place, from Florian Lehner,
KP Singh, Jiri Olsa and various others.
* https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next: (31 commits)
selftests/bpf: Add a test for ptr_to_map_value on stack for helper access
bpf: Permits pointers on stack for helper calls
libbpf: Expose libbpf ring_buffer epoll_fd
selftests/bpf: Add set_attach_target() API selftest for module target
libbpf: Support modules in bpf_program__set_attach_target() API
selftests/bpf: Silence ima_setup.sh when not running in verbose mode.
selftests/bpf: Drop the need for LLVM's llc
selftests/bpf: fix bpf_testmod.ko recompilation logic
samples/bpf: Fix possible hang in xdpsock with multiple threads
selftests/bpf: Make selftest compilation work on clang 11
selftests/bpf: Xsk selftests - adding xdpxceiver to .gitignore
selftests/bpf: Drop tcp-{client,server}.py from Makefile
selftests/bpf: Xsk selftests - Bi-directional Sockets - SKB, DRV
selftests/bpf: Xsk selftests - Socket Teardown - SKB, DRV
selftests/bpf: Xsk selftests - DRV POLL, NOPOLL
selftests/bpf: Xsk selftests - SKB POLL, NOPOLL
selftests/bpf: Xsk selftests framework
bpf: Only provide bpf_sock_from_file with CONFIG_NET
bpf: Return -ENOTSUPP when attaching to non-kernel BTF
xsk: Validate socket state in xsk_recvmsg, prior touching socket members
...
====================
Link: https://lore.kernel.org/r/20201214214316.20642-1-daniel@iogearbox.net
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
This provides a convenient perf ringbuf -> libbpf ringbuf migration
path for users of external polling systems. It is analogous to
perf_buffer__epoll_fd.
Signed-off-by: Brendan Jackman <jackmanb@google.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20201214113812.305274-1-jackmanb@google.com
Support finding kernel targets in kernel modules when using
bpf_program__set_attach_target() API. This brings it up to par with what
libbpf supports when doing declarative SEC()-based target determination.
Some minor internal refactoring was needed to make sure vmlinux BTF can be
loaded before bpf_object's load phase.
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20201211215825.3646154-2-andrii@kernel.org
xdp_return_frame_bulk() needs to pass a xdp_buff
to __xdp_return().
strlcpy got converted to strscpy but here it makes no
functional difference, so just keep the right code.
Conflicts:
net/netfilter/nf_tables_api.c
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Alexei Starovoitov says:
====================
pull-request: bpf-next 2020-12-03
The main changes are:
1) Support BTF in kernel modules, from Andrii.
2) Introduce preferred busy-polling, from Björn.
3) bpf_ima_inode_hash() and bpf_bprm_opts_set() helpers, from KP Singh.
4) Memcg-based memory accounting for bpf objects, from Roman.
5) Allow bpf_{s,g}etsockopt from cgroup bind{4,6} hooks, from Stanislav.
* https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next: (118 commits)
selftests/bpf: Fix invalid use of strncat in test_sockmap
libbpf: Use memcpy instead of strncpy to please GCC
selftests/bpf: Add fentry/fexit/fmod_ret selftest for kernel module
selftests/bpf: Add tp_btf CO-RE reloc test for modules
libbpf: Support attachment of BPF tracing programs to kernel modules
libbpf: Factor out low-level BPF program loading helper
bpf: Allow to specify kernel module BTFs when attaching BPF programs
bpf: Remove hard-coded btf_vmlinux assumption from BPF verifier
selftests/bpf: Add CO-RE relocs selftest relying on kernel module BTF
selftests/bpf: Add support for marking sub-tests as skipped
selftests/bpf: Add bpf_testmod kernel module for testing
libbpf: Add kernel module BTF support for CO-RE relocations
libbpf: Refactor CO-RE relocs to not assume a single BTF object
libbpf: Add internal helper to load BTF data by FD
bpf: Keep module's btf_data_size intact after load
bpf: Fix bpf_put_raw_tracepoint()'s use of __module_address()
selftests/bpf: Add Userspace tests for TCP_WINDOW_CLAMP
bpf: Adds support for setting window clamp
samples/bpf: Fix spelling mistake "recieving" -> "receiving"
bpf: Fix cold build of test_progs-no_alu32
...
====================
Link: https://lore.kernel.org/r/20201204021936.85653-1-alexei.starovoitov@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Some versions of GCC are really nit-picky about strncpy() use. Use memcpy(),
as they are pretty much equivalent for the case of fixed length strings.
Fixes: e459f49b43 ("libbpf: Separate XDP program load with xsk socket creation")
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20201203235440.2302137-1-andrii@kernel.org
Teach libbpf to search for BTF types in kernel modules for tracing BPF
programs. This allows attachment of raw_tp/fentry/fexit/fmod_ret/etc BPF
program types to tracepoints and functions in kernel modules.
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20201203204634.1325171-13-andrii@kernel.org
Refactor low-level API for BPF program loading to not rely on public API
types. This allows painless extension without constant efforts to cleverly not
break backwards compatibility.
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20201203204634.1325171-12-andrii@kernel.org
Teach libbpf to search for candidate types for CO-RE relocations across kernel
modules BTFs, in addition to vmlinux BTF. If at least one candidate type is
found in vmlinux BTF, kernel module BTFs are not iterated. If vmlinux BTF has
no matching candidates, then find all kernel module BTFs and search for all
matching candidates across all of them.
Kernel's support for module BTFs are inferred from the support for BTF name
pointer in BPF UAPI.
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20201203204634.1325171-6-andrii@kernel.org
Refactor CO-RE relocation candidate search to not expect a single BTF, rather
return all candidate types with their corresponding BTF objects. This will
allow to extend CO-RE relocations to accommodate kernel module BTFs.
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Link: https://lore.kernel.org/bpf/20201203204634.1325171-5-andrii@kernel.org
Add a btf_get_from_fd() helper, which constructs struct btf from in-kernel BTF
data by FD. This is used for loading module BTFs.
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20201203204634.1325171-4-andrii@kernel.org
I've seen a situation, where a process that's under pprof constantly
generates SIGPROF which prevents program loading indefinitely.
The right thing to do probably is to disable signals in the upper
layers while loading, but it still would be nice to get some error from
libbpf instead of an endless loop.
Let's add some small retry limit to the program loading:
try loading the program 5 (arbitrary) times and give up.
v2:
* 10 -> 5 retires (Andrii Nakryiko)
Signed-off-by: Stanislav Fomichev <sdf@google.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20201202231332.3923644-1-sdf@google.com
When we added sanitising of map names before loading programs to libbpf, we
still allowed periods in the name. While the kernel will accept these for
the map names themselves, they are not allowed in file names when pinning
maps. This means that bpf_object__pin_maps() will fail if called on an
object that contains internal maps (such as sections .rodata).
Fix this by replacing periods with underscores when constructing map pin
paths. This only affects the paths generated by libbpf when
bpf_object__pin_maps() is called with a path argument. Any pin paths set
by bpf_map__set_pin_path() are unaffected, and it will still be up to the
caller to avoid invalid characters in those.
Fixes: 113e6b7e15 ("libbpf: Sanitise internal map names so they are not rejected by the kernel")
Signed-off-by: Toke Høiland-Jørgensen <toke@redhat.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20201203093306.107676-1-toke@redhat.com
Before this patch, a program with unspecified type
(BPF_PROG_TYPE_UNSPEC) would be passed to the BPF syscall, only to have
the kernel reject it with an opaque invalid argument error. This patch
makes libbpf reject such programs with a nicer error message - in
particular libbpf now tries to diagnose bad ELF section names at both
open time and load time.
Signed-off-by: Andrei Matei <andreimatei1@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20201203043410.59699-1-andreimatei1@gmail.com
Add support for separation of eBPF program load and xsk socket
creation.
This is needed for use-case when you want to privide as little
privileges as possible to the data plane application that will
handle xsk socket creation and incoming traffic.
With this patch the data entity container can be run with only
CAP_NET_RAW capability to fulfill its purpose of creating xsk
socket and handling packages. In case your umem is larger or
equal process limit for MEMLOCK you need either increase the
limit or CAP_IPC_LOCK capability.
To resolve privileges issue two APIs are introduced:
- xsk_setup_xdp_prog - loads the built in XDP program. It can
also return xsks_map_fd which is needed by unprivileged process
to update xsks_map with AF_XDP socket "fd"
- xsk_socket__update_xskmap - inserts an AF_XDP socket into an xskmap
for a particular xsk_socket
Signed-off-by: Mariusz Dudek <mariuszx.dudek@intel.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Magnus Karlsson <magnus.karlsson@intel.com>
Link: https://lore.kernel.org/bpf/20201203090546.11976-2-mariuszx.dudek@intel.com
Fix ring_buffer__poll() to return the number of non-discarded records
consumed, just like its documentation states. It's also consistent with
ring_buffer__consume() return. Fix up selftests with wrong expected results.
Fixes: bf99c936f9 ("libbpf: Add BPF ring buffer support")
Fixes: cb1c9ddd55 ("selftests/bpf: Add BPF ringbuf selftests")
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20201130223336.904192-1-andrii@kernel.org
Replace size_t with __u32 in the xsk interfaces that contain this.
There is no reason to have size_t since the internal variable that
is manipulated is a __u32. The following APIs are affected:
__u32 xsk_ring_prod__reserve(struct xsk_ring_prod *prod, __u32 nb, __u32 *idx)
void xsk_ring_prod__submit(struct xsk_ring_prod *prod, __u32 nb)
__u32 xsk_ring_cons__peek(struct xsk_ring_cons *cons, __u32 nb, __u32 *idx)
void xsk_ring_cons__cancel(struct xsk_ring_cons *cons, __u32 nb)
void xsk_ring_cons__release(struct xsk_ring_cons *cons, __u32 nb)
The "nb" variable and the return values have been changed from size_t
to __u32.
Signed-off-by: Magnus Karlsson <magnus.karlsson@intel.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/1606383455-8243-1-git-send-email-magnus.karlsson@gmail.com
Add a new function for returning descriptors the user received
after an xsk_ring_cons__peek call. After the application has
gotten a number of descriptors from a ring, it might not be able
to or want to process them all for various reasons. Therefore,
it would be useful to have an interface for returning or
cancelling a number of them so that they are returned to the ring.
This patch adds a new function called xsk_ring_cons__cancel that
performs this operation on nb descriptors counted from the end of
the batch of descriptors that was received through the peek call.
Signed-off-by: Li RongQing <lirongqing@baidu.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
[ Magnus Karlsson: rewrote changelog ]
Acked-by: Magnus Karlsson <magnus.karlsson@intel.com>
Link: https://lore.kernel.org/bpf/1606202474-8119-1-git-send-email-lirongqing@baidu.com
We remove "other info" from "readelf -s --wide" output when
parsing GLOBAL_SYM_COUNT variable, which was added in [1].
But we don't do that for VERSIONED_SYM_COUNT and it's failing
the check_abi target on powerpc Fedora 33.
The extra "other info" wasn't problem for VERSIONED_SYM_COUNT
parsing until commit [2] added awk in the pipe, which assumes
that the last column is symbol, but it can be "other info".
Adding "other info" removal for VERSIONED_SYM_COUNT the same
way as we did for GLOBAL_SYM_COUNT parsing.
[1] aa915931ac ("libbpf: Fix readelf output parsing for Fedora")
[2] 746f534a48 ("tools/libbpf: Avoid counting local symbols in ABI check")
Fixes: 746f534a48 ("tools/libbpf: Avoid counting local symbols in ABI check")
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20201118211350.1493421-1-jolsa@kernel.org
When operating on split BTF, btf__find_by_name[_kind] will not
iterate over all types since they use btf->nr_types to show
the number of types to iterate over. For split BTF this is
the number of types _on top of base BTF_, so it will
underestimate the number of types to iterate over, especially
for vmlinux + module BTF, where the latter is much smaller.
Use btf__get_nr_types() instead.
Fixes: ba451366bf ("libbpf: Implement basic split BTF support")
Signed-off-by: Alan Maguire <alan.maguire@oracle.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/1605437195-2175-1-git-send-email-alan.maguire@oracle.com
Daniel Borkmann says:
====================
pull-request: bpf-next 2020-11-14
1) Add BTF generation for kernel modules and extend BTF infra in kernel
e.g. support for split BTF loading and validation, from Andrii Nakryiko.
2) Support for pointers beyond pkt_end to recognize LLVM generated patterns
on inlined branch conditions, from Alexei Starovoitov.
3) Implements bpf_local_storage for task_struct for BPF LSM, from KP Singh.
4) Enable FENTRY/FEXIT/RAW_TP tracing program to use the bpf_sk_storage
infra, from Martin KaFai Lau.
5) Add XDP bulk APIs that introduce a defer/flush mechanism to optimize the
XDP_REDIRECT path, from Lorenzo Bianconi.
6) Fix a potential (although rather theoretical) deadlock of hashtab in NMI
context, from Song Liu.
7) Fixes for cross and out-of-tree build of bpftool and runqslower allowing build
for different target archs on same source tree, from Jean-Philippe Brucker.
8) Fix error path in htab_map_alloc() triggered from syzbot, from Eric Dumazet.
9) Move functionality from test_tcpbpf_user into the test_progs framework so it
can run in BPF CI, from Alexander Duyck.
10) Lift hashtab key_size limit to be larger than MAX_BPF_STACK, from Florian Lehner.
Note that for the fix from Song we have seen a sparse report on context
imbalance which requires changes in sparse itself for proper annotation
detection where this is currently being discussed on linux-sparse among
developers [0]. Once we have more clarification/guidance after their fix,
Song will follow-up.
[0] https://lore.kernel.org/linux-sparse/CAHk-=wh4bx8A8dHnX612MsDO13st6uzAz1mJ1PaHHVevJx_ZCw@mail.gmail.com/T/https://lore.kernel.org/linux-sparse/20201109221345.uklbp3lzgq6g42zb@ltop.local/T/
* git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next: (66 commits)
net: mlx5: Add xdp tx return bulking support
net: mvpp2: Add xdp tx return bulking support
net: mvneta: Add xdp tx return bulking support
net: page_pool: Add bulk support for ptr_ring
net: xdp: Introduce bulking for xdp tx return path
bpf: Expose bpf_d_path helper to sleepable LSM hooks
bpf: Augment the set of sleepable LSM hooks
bpf: selftest: Use bpf_sk_storage in FENTRY/FEXIT/RAW_TP
bpf: Allow using bpf_sk_storage in FENTRY/FEXIT/RAW_TP
bpf: Rename some functions in bpf_sk_storage
bpf: Folding omem_charge() into sk_storage_charge()
selftests/bpf: Add asm tests for pkt vs pkt_end comparison.
selftests/bpf: Add skb_pkt_end test
bpf: Support for pointers beyond pkt_end.
tools/bpf: Always run the *-clean recipes
tools/bpf: Add bootstrap/ to .gitignore
bpf: Fix NULL dereference in bpf_task_storage
tools/bpftool: Fix build slowdown
tools/runqslower: Build bpftool using HOSTCC
tools/runqslower: Enable out-of-tree build
...
====================
Link: https://lore.kernel.org/r/20201114020819.29584-1-daniel@iogearbox.net
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
If BPF code contains unused BPF subprogram and there are no other subprogram
calls (which can realistically happen in real-world applications given
sufficiently smart Clang code optimizations), libbpf will erroneously assume
that subprograms are entry-point programs and will attempt to load them with
UNSPEC program type.
Fix by not relying on subcall instructions and rather detect it based on the
structure of BPF object's sections.
Fixes: 9a94f277c4 ("tools: libbpf: restore the ability to load programs from .text section")
Reported-by: Dmitrii Banshchikov <dbanschikov@fb.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20201107000251.256821-1-andrii@kernel.org
Updates the bpf_probe_map_type API to also support
BPF_MAP_TYPE_TASK_STORAGE similar to other local storage maps.
Signed-off-by: KP Singh <kpsingh@google.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Link: https://lore.kernel.org/bpf/20201106103747.2780972-4-kpsingh@chromium.org
In some cases compiler seems to generate distinct DWARF types for identical
arrays within the same CU. That seems like a bug, but it's already out there
and breaks type graph equivalence checks, so accommodate it anyway by checking
for identical arrays, regardless of their type ID.
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Song Liu <songliubraving@fb.com>
Link: https://lore.kernel.org/bpf/20201105043402.2530976-10-andrii@kernel.org
Add support for deduplication split BTFs. When deduplicating split BTF, base
BTF is considered to be immutable and can't be modified or adjusted. 99% of
BTF deduplication logic is left intact (module some type numbering adjustments).
There are only two differences.
First, each type in base BTF gets hashed (expect VAR and DATASEC, of course,
those are always considered to be self-canonical instances) and added into
a table of canonical table candidates. Hashing is a shallow, fast operation,
so mostly eliminates the overhead of having entire base BTF to be a part of
BTF dedup.
Second difference is very critical and subtle. While deduplicating split BTF
types, it is possible to discover that one of immutable base BTF BTF_KIND_FWD
types can and should be resolved to a full STRUCT/UNION type from the split
BTF part. This is, obviously, can't happen because we can't modify the base
BTF types anymore. So because of that, any type in split BTF that directly or
indirectly references that newly-to-be-resolved FWD type can't be considered
to be equivalent to the corresponding canonical types in base BTF, because
that would result in a loss of type resolution information. So in such case,
split BTF types will be deduplicated separately and will cause some
duplication of type information, which is unavoidable.
With those two changes, the rest of the algorithm manages to deduplicate split
BTF correctly, pointing all the duplicates to their canonical counter-parts in
base BTF, but also is deduplicating whatever unique types are present in split
BTF on their own.
Also, theoretically, split BTF after deduplication could end up with either
empty type section or empty string section. This is handled by libbpf
correctly in one of previous patches in the series.
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Song Liu <songliubraving@fb.com>
Link: https://lore.kernel.org/bpf/20201105043402.2530976-9-andrii@kernel.org
Make data section layout checks stricter, disallowing overlap of types and
strings data.
Additionally, allow BTFs with no type data. There is nothing inherently wrong
with having BTF with no types (put potentially with some strings). This could
be a situation with kernel module BTFs, if module doesn't introduce any new
type information.
Also fix invalid offset alignment check for btf->hdr->type_off.
Fixes: 8a138aed4a ("bpf: btf: Add BTF support to libbpf")
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20201105043402.2530976-8-andrii@kernel.org
Support split BTF operation, in which one BTF (base BTF) provides basic set of
types and strings, while another one (split BTF) builds on top of base's types
and strings and adds its own new types and strings. From API standpoint, the
fact that the split BTF is built on top of the base BTF is transparent.
Type numeration is transparent. If the base BTF had last type ID #N, then all
types in the split BTF start at type ID N+1. Any type in split BTF can
reference base BTF types, but not vice versa. Programmatically construction of
a split BTF on top of a base BTF is supported: one can create an empty split
BTF with btf__new_empty_split() and pass base BTF as an input, or pass raw
binary data to btf__new_split(), or use btf__parse_xxx_split() variants to get
initial set of split types/strings from the ELF file with .BTF section.
String offsets are similarly transparent and are a logical continuation of
base BTF's strings. When building BTF programmatically and adding a new string
(explicitly with btf__add_str() or implicitly through appending new
types/members), string-to-be-added would first be looked up from the base
BTF's string section and re-used if it's there. If not, it will be looked up
and/or added to the split BTF string section. Similarly to type IDs, types in
split BTF can refer to strings from base BTF absolutely transparently (but not
vice versa, of course, because base BTF doesn't "know" about existence of
split BTF).
Internal type index is slightly adjusted to be zero-indexed, ignoring a fake
[0] VOID type. This allows to handle split/base BTF type lookups transparently
by using btf->start_id type ID offset, which is always 1 for base/non-split
BTF and equals btf__get_nr_types(base_btf) + 1 for the split BTF.
BTF deduplication is not yet supported for split BTF and support for it will
be added in separate patch.
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Song Liu <songliubraving@fb.com>
Link: https://lore.kernel.org/bpf/20201105043402.2530976-5-andrii@kernel.org
Revamp BTF dedup's string deduplication to match the approach of writable BTF
string management. This allows to transfer deduplicated strings index back to
BTF object after deduplication without expensive extra memory copying and hash
map re-construction. It also simplifies the code and speeds it up, because
hashmap-based string deduplication is faster than sort + unique approach.
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Song Liu <songliubraving@fb.com>
Link: https://lore.kernel.org/bpf/20201105043402.2530976-4-andrii@kernel.org
