Two insn_buf[16] variables are declared in the function which acts on
function scope and block scope respectively. The statement in the inner
block is redundant, so remove it.

Signed-off-by: Jianlin Lv <Jianlin.Lv@arm.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20210318024851.49693-1-Jianlin.Lv@arm.com

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: 9f81654e

 ("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

Andrii Nakryiko says:

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

This patch set adds new libbpf APIs and their bpftool integration that allows
to perform static linking of BPF object files. Currently no extern resolution
across object files is performed. This is going to be the focus of the follow
up patches. But, given amount of code and logic necessary to perform just
basic functionality of linking together mostly independent BPF object files,
it was decided to land basic BPF linker code and logic first and extend it
afterwards.

The motivation for BPF static linking is to provide the functionality that is
naturally assumed for user-space development process: ability to structure
application's code without artificial restrictions of having all the code and
data (variables and maps) inside a single source code file.

This enables better engineering practices of splitting code into
well-encapsulated parts. It provides ability to hide internal state from other
parts of the code base through static variables and maps. It is also a first
steps towards having generic reusable BPF libraries.

Please see individual patches (mostly #6 and #7) for more details. Patch #10
passes all test_progs' individual BPF .o files through BPF static linker,
which is supposed to be a no-op operation, so is essentially validating that
BPF static linker doesn't produce corrupted ELF object files. Patch #11 adds
Makefile infra to be able to specify multi-file BPF object files and adds the
first multi-file test to validate correctness.

v3->v4:
  - fix Makefile copy/paste error of diff'ing invalid object files (Alexei);
  - fix uninitialized obj_name variable that could lead to bogus object names
    being used during skeleton generation (kernel-patches CI);
v2->v3:
  - added F(F(F(X))) = F(F(X)) test for all linked BPF object files (Alexei);
  - used reallocarray() more consistently in few places (Alexei);
  - improved bash completions for `gen object` (Quentin);
  - dropped .bpfo extension, but had to add optional `name OBJECT_FILE`
    parameter (path #8) to `gen skeleton` command to specify desired object
    name during skeleton generation;
  - fixed bug of merging DATASECS of special "license" and "version" sections.
    Linker currently strictly validates that all versions and licenses matches
    exactly and keeps only ELF symbols and BTF DATASEC from the very first
    object file with license/version. For all other object files, we ignore
    ELF symbols, but weren't ignoring DATASECs, which caused further problems
    of not being able to find a corresponding ELF symbol, if variable name
    differs between two files (which we test deliberately in multi-file
    linking selftest). The fix is to ignore BTF DATASECS;
v1->v2:
  - extracted `struct strset` to manage unique set of strings both for BTF and
    ELF SYMTAB (patch #4, refactors btf and btf_dedup logic as well) (Alexei);
  - fixed bugs in bpftool gen command; renamed it to `gen object`, added BASH
    completions and extended/updated man page (Quentin).
====================

Signed-off-by: Alexei Starovoitov <ast@kernel.org>

Add Makefile infra to specify multi-file BPF object files (and derivative
skeletons). Add first selftest validating BPF static linker can merge together
successfully two independent BPF object files and resulting object and
skeleton are correct and usable.

Use the same F(F(F(X))) = F(F(X)) identity test on linked object files as for
the case of single BPF object files.

Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20210318194036.3521577-13-andrii@kernel.org

Pass all individual BPF object files (generated from progs/*.c) through
`bpftool gen object` command to validate that BPF static linker doesn't
corrupt them.

As an additional sanity checks, validate that passing resulting object files
through linker again results in identical ELF files. Exact same ELF contents
can be guaranteed only after two passes, as after the first pass ELF sections
order changes, and thus .BTF.ext data sections order changes. That, in turn,
means that strings are added into the final BTF string sections in different
order, so .BTF strings data might not be exactly the same. But doing another
round of linking afterwards should result in the identical ELF file, which is
checked with additional `diff` command.

Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20210318194036.3521577-12-andrii@kernel.org

Trigger vmlinux.h and BPF skeletons re-generation if detected that bpftool was
re-compiled. Otherwise full `make clean` is required to get updated skeletons,
if bpftool is modified.

Fixes: acbd0620

 ("selftests/bpf: Add vmlinux.h selftest exercising tracing of syscalls")
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20210318194036.3521577-11-andrii@kernel.org

Add `bpftool gen object <output-file> <input_file>...` command to statically
link multiple BPF ELF object files into a single output BPF ELF object file.

This patch also updates bash completions and man page. Man page gets a short
section on `gen object` command, but also updates the skeleton example to show
off workflow for BPF application with two .bpf.c files, compiled individually
with Clang, then resulting object files are linked together with `gen object`,
and then final object file is used to generate usable BPF skeleton. This
should help new users understand realistic workflow w.r.t. compiling
mutli-file BPF application.

Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Reviewed-by: Quentin Monnet <quentin@isovalent.com>
Link: https://lore.kernel.org/bpf/20210318194036.3521577-10-andrii@kernel.org

Add optional name OBJECT_NAME parameter to `gen skeleton` command to override
default object name, normally derived from input file name. This allows much
more flexibility during build time.

Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20210318194036.3521577-9-andrii@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

We want to change the current ndo_xdp_xmit drop semantics because it will
allow us to implement better queue overflow handling. This is working
towards the larger goal of a XDP TX queue-hook. Move XDP_REDIRECT error
path handling from each XDP ethernet driver to devmap code. According to
the new APIs, the driver running the ndo_xdp_xmit pointer, will break tx
loop whenever the hw reports a tx error and it will just return to devmap
caller the number of successfully transmitted frames. It will be devmap
responsibility to free dropped frames.

Move each XDP ndo_xdp_xmit capable driver to the new APIs:

- veth
- virtio-net
- mvneta
- mvpp2
- socionext
- amazon ena
- bnxt
- freescale (dpaa2, dpaa)
- xen-frontend
- qede
- ice
- igb
- ixgbe
- i40e
- mlx5
- ti (cpsw, cpsw-new)
- tun
- sfc

Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Reviewed-by: Ioana Ciornei <ioana.ciornei@nxp.com>
Reviewed-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>
Reviewed-by: Camelia Groza <camelia.groza@nxp.com>
Acked-by: Edward Cree <ecree.xilinx@gmail.com>
Acked-by: Jesper Dangaard Brouer <brouer@redhat.com>
Acked-by: Shay Agroskin <shayagr@amazon.com>
Link: https://lore.kernel.org/bpf/ed670de24f951cfd77590decf0229a0ad7fd12f6.1615201152.git.lorenzo@kernel.org

Andrii Nakryiko says:

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

Provide NULL and KERNEL_VERSION macros in bpf_helpers.h. Patch #2 removes such
custom NULL definition from one of the selftests.

v2->v3:
  - instead of vmlinux.h, do this in bpf_helpers.h;
  - added KERNEL_VERSION, which comes up periodically as well;
  - I dropped strict compilation patches for now, because we run into new
    warnings (e.g., not checking read() result) in kernel-patches CI, which
    I can't even reproduce locally. Also -Wdiscarded-qualifiers pragma for
    jit_disasm.c is not supported by Clang, it needs to be
    -Wincompatible-pointer-types-discards-qualifiers for Clang; we don't have
    to deal with that in this patch set;
v1->v2:
  - fix few typos and wrong copy/paste;
  - fix #pragma push -> pop.
====================

Signed-off-by: Alexei Starovoitov <ast@kernel.org>

Now that bpftool generates NULL definition as part of vmlinux.h, drop custom
NULL definition in skb_pkt_end.c.

Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20210317200510.1354627-3-andrii@kernel.org


Signed-off-by: Alexei Starovoitov <ast@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>

The selftest failed to compile with clang-built bpf-next.
Adding LLVM=1 to your vmlinux and selftest build will use clang.
The error message is:
  progs/test_sk_storage_tracing.c:38:18: error: use of undeclared identifier 'BPF_TCP_CLOSE'
          if (newstate == BPF_TCP_CLOSE)
                          ^
  1 error generated.
  make: *** [Makefile:423: /bpf-next/tools/testing/selftests/bpf/test_sk_storage_tracing.o] Error 1

The reason for the failure is that BPF_TCP_CLOSE, a value of
an anonymous enum defined in uapi bpf.h, is not defined in
vmlinux.h. gcc does not have this problem. Since vmlinux.h
is derived from BTF which is derived from vmlinux DWARF,
that means gcc-produced vmlinux DWARF has BPF_TCP_CLOSE
while llvm-produced vmlinux DWARF does not have.

BPF_TCP_CLOSE is referenced in net/ipv4/tcp.c as
  BUILD_BUG_ON((int)BPF_TCP_CLOSE != (int)TCP_CLOSE);
The following test mimics the above BUILD_BUG_ON, preprocessed
with clang compiler, and shows gcc DWARF contains BPF_TCP_CLOSE while
llvm DWARF does not.

  $ cat t.c
  enum {
    BPF_TCP_ESTABLISHED = 1,
    BPF_TCP_CLOSE = 7,
  };
  enum {
    TCP_ESTABLISHED = 1,
    TCP_CLOSE = 7,
  };

  int test() {
    do {
      extern void __compiletime_assert_767(void) ;
      if ((int)BPF_TCP_CLOSE != (int)TCP_CLOSE) __compiletime_assert_767();
    } while (0);
    return 0;
  }
  $ clang t.c -O2 -c -g && llvm-dwarfdump t.o | grep BPF_TCP_CLOSE
  $ gcc t.c -O2 -c -g && llvm-dwarfdump t.o | grep BPF_TCP_CLOSE
                    DW_AT_name    ("BPF_TCP_CLOSE")

Further checking clang code find clang actually tried to
evaluate condition at compile time. If it is definitely
true/false, it will perform optimization and the whole if condition
will be removed before generating IR/debuginfo.

This patch explicited add an expression after the
above mentioned BUILD_BUG_ON in net/ipv4/tcp.c like
  (void)BPF_TCP_ESTABLISHED
to enable generation of debuginfo for the anonymous
enum which also includes BPF_TCP_CLOSE.

Signed-off-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20210317174132.589276-1-yhs@fb.com

Glibc's sleep() switched to clock_nanosleep() from nanosleep(), and thus
syscalls:sys_enter_nanosleep tracepoint is not hitting which is causing
testcase failure. Instead of depending on glibc sleep(), call nanosleep()
systemcall directly.

Before:

  # ./get_cgroup_id_user
  ...
  main:FAIL:compare_cgroup_id kern cgid 0 user cgid 483

After:

  # ./get_cgroup_id_user
  ...
  main:PASS:compare_cgroup_id

Signed-off-by: Ravi Bangoria <ravi.bangoria@linux.ibm.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20210316153048.136447-1-ravi.bangoria@linux.ibm.com

Fix the following coccicheck warnings:

  ./tools/testing/selftests/bpf/progs/fexit_test.c:77:15-16: WARNING
  comparing pointer to 0.

  ./tools/testing/selftests/bpf/progs/fexit_test.c:68:12-13: WARNING
  comparing pointer to 0.

Reported-by: Abaci Robot <abaci@linux.alibaba.com>
Signed-off-by: Jiapeng Chong <jiapeng.chong@linux.alibaba.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/1615881577-3493-1-git-send-email-jiapeng.chong@linux.alibaba.com

Andrii Nakryiko says:

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

Build BPF selftests and libbpf and bpftool, that are used as part of
selftests, in debug mode (specifically, -Og). This makes it much simpler and
nicer to do development and/or bug fixing. See patch #4 for some unscientific
measurements.

This patch set fixes new maybe-unitialized warnings produced in -Og build
mode. Patch #1 fixes the blocker which was causing some XDP selftests failures
due to non-zero padding in bpf_xdp_set_link_opts, which only happened in debug
mode.
====================

Signed-off-by: Alexei Starovoitov <ast@kernel.org>

Build selftests, bpftool, and libbpf in debug mode with DWARF data to
facilitate easier debugging.

In terms of impact on building and running selftests. Build is actually faster
now:

BEFORE: make -j60  380.21s user 37.87s system 1466% cpu 28.503 total
AFTER:  make -j60  345.47s user 37.37s system 1599% cpu 23.939 total

test_progs runtime seems to be the same:

BEFORE:
real    1m5.139s
user    0m1.600s
sys     0m43.977s

AFTER:
real    1m3.799s
user    0m1.721s
sys     0m42.420s

Huge difference is being able to debug issues throughout test_progs, bpftool,
and libbpf without constantly updating 3 Makefiles by hand (including GDB
seeing the source code without any extra incantations).

Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20210313210920.1959628-5-andrii@kernel.org

xsk_ring_prod__reserve() doesn't necessarily set idx in some conditions, so
from static analysis point of view compiler is right about the problems like:

In file included from xdpxceiver.c:92:
xdpxceiver.c: In function ‘xsk_populate_fill_ring’:
/data/users/andriin/linux/tools/testing/selftests/bpf/tools/include/bpf/xsk.h:119:20: warning: ‘idx’ may be used uninitialized in this function [-Wmaybe-uninitialized]
  return &addrs[idx & fill->mask];
                ~~~~^~~~~~~~~~~~
xdpxceiver.c:300:6: note: ‘idx’ was declared here
  u32 idx;
      ^~~
xdpxceiver.c: In function ‘tx_only’:
xdpxceiver.c:596:30: warning: ‘idx’ may be used uninitialized in this function [-Wmaybe-uninitialized]
   struct xdp_desc *tx_desc = xsk_ring_prod__tx_desc(&xsk->tx, idx + i);
                              ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Fix two warnings reported by compiler by pre-initializing variable.

Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20210313210920.1959628-4-andrii@kernel.org

Somehow when bpftool is compiled in -Og mode, compiler produces new warnings
about possibly uninitialized variables. Fix all the reported problems.

Fixes: 2119f218

 ("bpftool: add C output format option to btf dump subcommand")
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20210313210920.1959628-3-andrii@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: bd5ca3ef

 ("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

The sparse tool complains as follows:

kernel/bpf/bpf_task_storage.c:23:1: warning:
 symbol '__pcpu_scope_bpf_task_storage_busy' was not declared. Should it be static?

This symbol is not used outside of bpf_task_storage.c, so this
commit marks it static.

Fixes: bc235cdb

 ("bpf: Prevent deadlock from recursive bpf_task_storage_[get|delete]")
Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Wei Yongjun <weiyongjun1@huawei.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Song Liu <songliubraving@fb.com>
Link: https://lore.kernel.org/bpf/20210311131505.1901509-1-weiyongjun1@huawei.com

A typo is found out by codespell tool in 34th lines of hashtab.c:

$ codespell ./kernel/bpf/
./hashtab.c:34 : differrent ==> different

Fix a typo found by codespell.

Signed-off-by: Liu xuzhi <liu.xuzhi@zte.com.cn>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20210311123103.323589-1-liu.xuzhi@zte.com.cn

Implement BPF_AND, BPF_OR and BPF_XOR as the existing BPF_ADD. Since
the corresponding machine instructions return the old value, BPF_FETCH
happens by itself, the only additional thing that is required is
zero-extension.

There is no single instruction that implements BPF_XCHG on s390, so use
a COMPARE AND SWAP loop.

BPF_CMPXCHG, on the other hand, can be implemented by a single COMPARE
AND SWAP. Zero-extension is automatically inserted by the verifier.

Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20210304233002.149096-1-iii@linux.ibm.com

This seems to be a reminiscent from the hashmap tests.

Signed-off-by: Pedro Tammela <pctammela@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20210315132954.603108-1-pctammela@gmail.com

This patch fixes a spelling typo in do_hbm_test.sh

Signed-off-by: Masanari Iida <standby24x7@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20210315124454.1744594-1-standby24x7@gmail.com

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

Augment the current set of options that are accessible via
bpf_{g,s}etsockopt to also support SO_REUSEPORT.

Signed-off-by: Manu Bretelle <chantra@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Link: https://lore.kernel.org/bpf/20210310182305.1910312-1-chantra@fb.com

Björn Töpel says:

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

This series removes a header dependency from xsk.h, and moves
libbpf_util.h into xsk.h.

More details in each commit!

Thank you,
Björn
====================

Signed-off-by: Andrii Nakryiko <andrii@kernel.org>

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 291471dd

 ("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

Fix the following coccicheck warning:

./tools/testing/selftests/bpf/progs/fentry_test.c:67:12-13: WARNING
comparing pointer to 0.

Reported-by: Abaci Robot <abaci@linux.alibaba.com>
Signed-off-by: Jiapeng Chong <jiapeng.chong@linux.alibaba.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/1615360714-30381-1-git-send-email-jiapeng.chong@linux.alibaba.com

Fix the following coccicheck warning:

./tools/testing/selftests/bpf/progs/test_global_func10.c:17:12-13:
WARNING comparing pointer to 0.

Reported-by: Abaci Robot <abaci@linux.alibaba.com>
Signed-off-by: Jiapeng Chong <jiapeng.chong@linux.alibaba.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/1615357366-97612-1-git-send-email-jiapeng.chong@linux.alibaba.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>