Add ability to mark arg:trusted arguments with optional arg:nullable
tag to mark it as PTR_TO_BTF_ID_OR_NULL variant, which will allow
callers to pass NULL, and subsequently will force global subprog's code
to do NULL check. This allows to have "optional" PTR_TO_BTF_ID values
passed into global subprogs.

For now arg:nullable cannot be combined with anything else.
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20240130000648.2144827-3-andrii@kernel.orgSigned-off-by: Alexei Starovoitov <ast@kernel.org>

Add support for passing PTR_TO_BTF_ID registers to global subprogs.
Currently only PTR_TRUSTED flavor of PTR_TO_BTF_ID is supported.
Non-NULL semantics is assumed, so caller will be forced to prove
PTR_TO_BTF_ID can't be NULL.

Note, we disallow global subprogs to destroy passed in PTR_TO_BTF_ID
arguments, even the trusted one. We achieve that by not setting
ref_obj_id when validating subprog code. This basically enforces (in
Rust terms) borrowing semantics vs move semantics. Borrowing semantics
seems to be a better fit for isolated global subprog validation
approach.

Implementation-wise, we utilize existing logic for matching
user-provided BTF type to kernel-side BTF type, used by BPF CO-RE logic
and following same matching rules. We enforce a unique match for types.
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20240130000648.2144827-2-andrii@kernel.orgSigned-off-by: Alexei Starovoitov <ast@kernel.org>

Clang supports enabling/disabling certain conversion diagnostics via
the -W[no-]compare-distinct-pointer-types command line options.
Disabling this warning is required by some BPF selftests due to
-Werror.  Until very recently GCC would emit these warnings
unconditionally, which was a problem for gcc-bpf, but we added support
for the command-line options to GCC upstream [1].

This patch moves the -Wno-cmopare-distinct-pointer-types from
CLANG_CFLAGS to BPF_CFLAGS in selftests/bpf/Makefile so the option
is also used in gcc-bpf builds, not just in clang builds.

Tested in bpf-next master.
No regressions.

  [1] https://gcc.gnu.org/pipermail/gcc-patches/2023-August/627769.htmlSigned-off-by: Jose E. Marchesi <jose.marchesi@oracle.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20240130113624.24940-1-jose.marchesi@oracle.com

A few BPF selftests perform type punning and they may break strict
aliasing rules, which are exploited by both GCC and clang by default
while optimizing.  This can lead to broken compiled programs.

This patch disables strict aliasing for these particular tests, by
mean of the -fno-strict-aliasing command line option.  This will make
sure these tests are optimized properly even if some strict aliasing
rule gets violated.

After this patch, GCC is able to build all the selftests without
warning about potential strict aliasing issue.

bpf@vger discussion on strict aliasing and BPF selftests:
https://lore.kernel.org/bpf/bae1205a-b6e5-4e46-8e20-520d7c327f7a@linux.dev/T/#t

Tested in bpf-next master.
No regressions.
Signed-off-by: Jose E. Marchesi <jose.marchesi@oracle.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/bae1205a-b6e5-4e46-8e20-520d7c327f7a@linux.dev
Link: https://lore.kernel.org/bpf/20240130110343.11217-1-jose.marchesi@oracle.com

Replace the '(1ULL << *)' with the macro BIT_ULL(nr).
Signed-off-by: Haiyue Wang <haiyue.wang@intel.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20240127134901.3698613-1-haiyue.wang@intel.com

The generated bpf_helper_defs.h file currently contains definitions
like this for the kernel helpers, which are static objects:

  static void *(*bpf_map_lookup_elem)(void *map, const void *key) = (void *) 1;

These work well in both clang and GCC because both compilers do
constant propagation with -O1 and higher optimization, resulting in
`call 1' BPF instructions being generated, which are calls to kernel
helpers.

However, there is a discrepancy on how the -Wunused-variable
warning (activated by -Wall) is handled in these compilers:

- clang will not emit -Wunused-variable warnings for static variables
  defined in C header files, be them constant or not constant.

- GCC will not emit -Wunused-variable warnings for _constant_ static
  variables defined in header files, but it will emit warnings for
  non-constant static variables defined in header files.

There is no reason for these bpf_helpers_def.h pointers to not be
declared constant, and it is actually desirable to do so, since their
values are not to be changed.  So this patch modifies bpf_doc.py to
generate prototypes like:

  static void *(* const bpf_map_lookup_elem)(void *map, const void *key) = (void *) 1;

This allows GCC to not error while compiling BPF programs with `-Wall
-Werror', while still being able to detect and error on legitimate
unused variables in the program themselves.

This change doesn't impact the desired constant propagation in neither
Clang nor GCC with -O1 and higher.  On the contrary, being declared as
constant may increase the odds they get constant folded when
used/referred to in certain circumstances.

Tested in bpf-next master.
No regressions.
Signed-off-by: Jose E. Marchesi <jose.marchesi@oracle.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Yonghong Song <yonghong.song@linux.dev>
Link: https://lore.kernel.org/bpf/20240127185031.29854-1-jose.marchesi@oracle.com

As CONFIG_DEBUG_INFO_BTF is default off the existing "failed to find
valid kernel BTF" message makes diagnosing the kernel build issue somewhat
cryptic. Add a little more detail with the hope of helping users.

Before:
```
libbpf: failed to find valid kernel BTF
libbpf: Error loading vmlinux BTF: -3
```

After not accessible:
```
libbpf: kernel BTF is missing at '/sys/kernel/btf/vmlinux', was CONFIG_DEBUG_INFO_BTF enabled?
libbpf: failed to find valid kernel BTF
libbpf: Error loading vmlinux BTF: -3
```

After not readable:
```
libbpf: failed to read kernel BTF from (/sys/kernel/btf/vmlinux): -1
```

Closes: https://lore.kernel.org/bpf/CAP-5=fU+DN_+Y=Y4gtELUsJxKNDDCOvJzPHvjUVaUoeFAzNnig@mail.gmail.com/Signed-off-by: Ian Rogers <irogers@google.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20240125231840.1647951-1-irogers@google.com

Remove the duplicate check on type and unify result.
Signed-off-by: Florian Lehner <dev@der-flo.net>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Song Liu <song@kernel.org>
Link: https://lore.kernel.org/bpf/20240120150920.3370-1-dev@der-flo.net

Certain BPF selftests contain code that, albeit being legal C, trigger
warnings in GCC that cannot be disabled.  This is the case for example
for the tests

  progs/btf_dump_test_case_bitfields.c
  progs/btf_dump_test_case_namespacing.c
  progs/btf_dump_test_case_packing.c
  progs/btf_dump_test_case_padding.c
  progs/btf_dump_test_case_syntax.c

which contain struct type declarations inside function parameter
lists.  This is problematic, because:

- The BPF selftests are built with -Werror.

- The Clang and GCC compilers sometimes differ when it comes to handle
  warnings.  in the handling of warnings.  One compiler may emit
  warnings for code that the other compiles compiles silently, and one
  compiler may offer the possibility to disable certain warnings, while
  the other doesn't.

In order to overcome this problem, this patch modifies the
tools/testing/selftests/bpf/Makefile in order to:

1. Enable the possibility of specifing per-source-file extra CFLAGS.
   This is done by defining a make variable like:

   <source-filename>-CFLAGS := <whateverflags>

   And then modifying the proper Make rule in order to use these flags
   when compiling <source-filename>.

2. Use the mechanism above to add -Wno-error to CFLAGS for the
   following selftests:

   progs/btf_dump_test_case_bitfields.c
   progs/btf_dump_test_case_namespacing.c
   progs/btf_dump_test_case_packing.c
   progs/btf_dump_test_case_padding.c
   progs/btf_dump_test_case_syntax.c

   Note the corresponding -CFLAGS variables for these files are
   defined only if the selftests are being built with GCC.

Note that, while compiler pragmas can generally be used to disable
particular warnings per file, this 1) is only possible for warning
that actually can be disabled in the command line, i.e. that have
-Wno-FOO options, and 2) doesn't apply to -Wno-error.

Tested in bpf-next master branch.
No regressions.
Signed-off-by: Jose E. Marchesi <jose.marchesi@oracle.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20240127100702.21549-1-jose.marchesi@oracle.com

In s390, CI reported that the sock_iter_batch selftest
hits this error very often:

2024-01-26T16:56:49.3091804Z Bind /proc/self/ns/net -> /run/netns/sock_iter_batch_netns failed: No such file or directory
2024-01-26T16:56:49.3149524Z Cannot remove namespace file "/run/netns/sock_iter_batch_netns": No such file or directory
2024-01-26T16:56:49.3772213Z test_sock_iter_batch:FAIL:ip netns add sock_iter_batch_netns unexpected error: 256 (errno 0)

It happens very often in s390 but Manu also noticed it happens very
sparsely in other arch also.

It turns out the default dash shell does not recognize "&>"
as a redirection operator, so the command went to the background.
In the sock_iter_batch selftest, the "ip netns delete" went
into background and then race with the following "ip netns add"
command.

This patch replaces the "&> /dev/null" usage with ">/dev/null 2>&1"
and does this redirection in the SYS_NOFAIL macro instead of doing
it individually by its caller. The SYS_NOFAIL callers do not care
about failure, so it is no harm to do this redirection even if
some of the existing callers do not redirect to /dev/null now.

It touches different test files, so I skipped the Fixes tags
in this patch. Some of the changed tests do not use "&>"
but they use the SYS_NOFAIL, so these tests are also
changed to avoid doing its own redirection because
SYS_NOFAIL does it internally now.
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Link: https://lore.kernel.org/r/20240127025017.950825-1-martin.lau@linux.devSigned-off-by: Alexei Starovoitov <ast@kernel.org>

Now that bpf and bpf-next trees converged and we don't run the risk of
merge conflicts, move btf_validate_prog_ctx_type() into its most logical
place inside the main logic loop.
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20240125205510.3642094-4-andrii@kernel.orgSigned-off-by: Alexei Starovoitov <ast@kernel.org>

Adjust PERF_EVENT type enforcement around __arg_ctx to match exactly
what kernel is doing.

Fixes: 76ec90a9 ("libbpf: warn on unexpected __arg_ctx type when rewriting BTF")
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20240125205510.3642094-3-andrii@kernel.orgSigned-off-by: Alexei Starovoitov <ast@kernel.org>

Now that feature detection code is in bpf-next tree, integrate __arg_ctx
kernel-side support into kernel_supports() framework.
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20240125205510.3642094-2-andrii@kernel.orgSigned-off-by: Alexei Starovoitov <ast@kernel.org>

For 64-bit immediate instruction, 'BPF_IMM | BPF_DW | BPF_LD' and
src_reg=[0-6], the current documentation describes the 64-bit
immediate is constructed by:

  imm64 = (next_imm << 32) | imm

But actually imm64 is only used when src_reg=0. For all other
variants (src_reg != 0), 'imm' and 'next_imm' have separate special
encoding requirement and imm64 cannot be easily used to describe
instruction semantics.

This patch clarifies that 64-bit immediate instructions use
two 32-bit immediate values instead of a 64-bit immediate value,
so later describing individual 64-bit immediate instructions
becomes less confusing.
Signed-off-by: Yonghong Song <yonghong.song@linux.dev>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Dave Thaler <dthaler1968@gmail.com>
Link: https://lore.kernel.org/bpf/20240127194629.737589-1-yonghong.song@linux.dev

It seems that the field "mod" in struct bpf_trampoline is not used
anywhere after the commit 31bf1dbc ("bpf: Fix attaching
fentry/fexit/fmod_ret/lsm to modules"). So we can just remove it now.

Fixes: 31bf1dbc ("bpf: Fix attaching fentry/fexit/fmod_ret/lsm to modules")
Signed-off-by: Menglong Dong <dongmenglong.8@bytedance.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Link: https://lore.kernel.org/bpf/20240128055443.413291-1-dongmenglong.8@bytedance.com

bpf_testmod_exit() does not need to have a return value (given the void),
so this patch drops this useless 'return' in it.
Signed-off-by: Geliang Tang <tanggeliang@kylinos.cn>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Link: https://lore.kernel.org/bpf/5765b287ea088f0c820f2a834faf9b20fb2f8215.1706442113.git.tanggeliang@kylinos.cn

Optimize bswap instructions by rev8 Zbb instruction conbined with srli
instruction. And Optimize 16-bit zero-extension with Zbb support.
Signed-off-by: Pu Lehui <pulehui@huawei.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Tested-by: Björn Töpel <bjorn@rivosinc.com>
Acked-by: Björn Töpel <bjorn@kernel.org>
Link: https://lore.kernel.org/bpf/20240115131235.2914289-7-pulehui@huaweicloud.com

Add 8-bit and 16-bit sign-extention wraper with Zbb support to optimize
sign-extension mov instructions.
Signed-off-by: Pu Lehui <pulehui@huawei.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Tested-by: Björn Töpel <bjorn@rivosinc.com>
Acked-by: Björn Töpel <bjorn@kernel.org>
Link: https://lore.kernel.org/bpf/20240115131235.2914289-6-pulehui@huaweicloud.com

Add necessary Zbb instructions introduced by [0] to reduce code size and
improve performance of RV64 JIT. Meanwhile, a runtime deteted helper is
added to check whether the CPU supports Zbb instructions.
Signed-off-by: Pu Lehui <pulehui@huawei.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Tested-by: Björn Töpel <bjorn@rivosinc.com>
Acked-by: Björn Töpel <bjorn@kernel.org>
Link: https://github.com/riscv/riscv-bitmanip/releases/download/1.0.0/bitmanip-1.0.0-38-g865e7a7.pdf [0]
Link: https://lore.kernel.org/bpf/20240115131235.2914289-5-pulehui@huaweicloud.com

There are many extension helpers in the current branch instructions, and
the implementation is a bit complicated. We simplify this logic through
two simple extension helpers with alternate register.
Signed-off-by: Pu Lehui <pulehui@huawei.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Tested-by: Björn Töpel <bjorn@rivosinc.com>
Acked-by: Björn Töpel <bjorn@kernel.org>
Link: https://lore.kernel.org/bpf/20240115131235.2914289-4-pulehui@huaweicloud.com

For code unification, add emit_zextw wrapper to unify all the 32-bit
zero-extension operations.
Signed-off-by: Pu Lehui <pulehui@huawei.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Tested-by: Björn Töpel <bjorn@rivosinc.com>
Acked-by: Björn Töpel <bjorn@kernel.org>
Link: https://lore.kernel.org/bpf/20240115131235.2914289-3-pulehui@huaweicloud.com

For code unification, add emit_sextw wrapper to unify all the 32-bit
sign-extension operations.
Signed-off-by: Pu Lehui <pulehui@huawei.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Tested-by: Björn Töpel <bjorn@rivosinc.com>
Acked-by: Björn Töpel <bjorn@kernel.org>
Link: https://lore.kernel.org/bpf/20240115131235.2914289-2-pulehui@huaweicloud.com

Android implementation of libc errors out with -EINVAL in faccessat() if
passed AT_EACCESS ([0]), this leads to ridiculous issue with libbpf
refusing to load /sys/kernel/btf/vmlinux on Androids ([1]). Fix by
detecting Android and redefining AT_EACCESS to 0, it's equivalent on
Android.

  [0] https://android.googlesource.com/platform/bionic/+/refs/heads/android13-release/libc/bionic/faccessat.cpp#50
  [1] https://github.com/libbpf/libbpf-bootstrap/issues/250#issuecomment-1911324250

Fixes: 6a4ab886 ("libbpf: Fix the case of running as non-root with capabilities")
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Link: https://lore.kernel.org/bpf/20240126220944.2497665-1-andrii@kernel.org

musl libc had the basename() prototype in string.h, but this is a
glibc-ism, now they removed the _GNU_SOURCE bits in their devel distro,
Alpine Linux edge:

  https://git.musl-libc.org/cgit/musl/commit/?id=725e17ed6dff4d0cd22487bb64470881e86a92e7

So lets use the POSIX version, the whole rationale is spelled out at:

  https://gitlab.alpinelinux.org/alpine/aports/-/issues/15643Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Jiri Olsa <olsajiri@gmail.com>
Acked-by: Quentin Monnet <quentin@isovalent.com>
Link: https://lore.kernel.org/lkml/ZZhsPs00TI75RdAr@kernel.org
Link: https://lore.kernel.org/bpf/Zbe3NuOgaupvUcpF@kernel.org

We had to add another synchronize_rcu() in recent fix.
Bite the bullet and add an rcu_head to netdev_name_node,
free from RCU.

Note that name_node does not hold any reference on dev
to which it points, but there must be a synchronize_rcu()
on device removal path, so we should be fine.
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Reviewed-by: Jiri Pirko <jiri@nvidia.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

The TRF7970A is a SPI device, not I2C.
Signed-off-by: Tobias Schramm <t.schramm@manjaro.org>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

The RENESAS FemtoClock3 Wireless is a high-performance jitter attenuator,
frequency translator, and clock synthesizer. The device is comprised of 3
digital PLLs (DPLL) to track CLKIN inputs and three independent low phase
noise fractional output dividers (FOD) that output low phase noise clocks.

FemtoClock3 supports one Time Synchronization (Time Sync) channel to enable
an external processor to control the phase and frequency of the Time Sync
channel and to take phase measurements using the TDC. Intended applications
are synchronization using the precision time protocol (PTP) and
synchronization with 0.5 Hz and 1 Hz signals from GNSS.
Signed-off-by: Min Li <min.li.xe@renesas.com>
Acked-by: Lee Jones <lee@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

This change is for the PHC devices that can measure the phase offset
between PHC signal and the external signal, such as the 1PPS signal of
GNSS. Reporting PTP_CLOCK_EXTOFF to user space will be piggy-backed to
the existing ptp_extts_event so that application such as ts2phc can
poll the external offset the same way as extts. Hence, ts2phc can use
the offset to achieve the alignment between PHC and the external signal
by the help of either SW or HW filters.
Signed-off-by: Min Li <min.li.xe@renesas.com>
Acked-by: Richard Cochran <richardcochran@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Breno Leitao says:

====================
Fix MODULE_DESCRIPTION() for net (p3)

There are hundreds of network modules that misses MODULE_DESCRIPTION(),
causing a warning when compiling with W=1. Example:

        WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/net/arcnet/com90io.o
        WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/net/arcnet/arc-rimi.o
        WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/net/arcnet/com20020.o

This part3 of the patchset focus on the missing ethernet drivers, which
is now warning free. This also fixes net/pcs and ieee802154.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

W=1 builds now warn if module is built without a MODULE_DESCRIPTION().
Add descriptions to arcnet module.
Signed-off-by: Breno Leitao <leitao@debian.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

W=1 builds now warn if module is built without a MODULE_DESCRIPTION().
Add descriptions to ieee802154 modules.
Signed-off-by: Breno Leitao <leitao@debian.org>
Acked-by: Miquel Raynal <miquel.raynal@bootlin.com>
Acked-by: Stefan Schmidt <stefan@datenfreihafen.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

W=1 builds now warn if module is built without a MODULE_DESCRIPTION().
Add descriptions to the Lynx, XPCS and LynxI PCS drivers.
Signed-off-by: Breno Leitao <leitao@debian.org>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>

W=1 builds now warn if module is built without a MODULE_DESCRIPTION().
Add descriptions to the Beckhoff CX5020 EtherCAT Ethernet driver.
Signed-off-by: Breno Leitao <leitao@debian.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

W=1 builds now warn if module is built without a MODULE_DESCRIPTION().
Add descriptions to the TI CPSW switch module.
Signed-off-by: Breno Leitao <leitao@debian.org>
Reviewed-by: Roger Quadros <rogerq@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

W=1 builds now warn if module is built without a MODULE_DESCRIPTION().
Add descriptions to the STMicro DWMAC for Altera SOCs.
Signed-off-by: Breno Leitao <leitao@debian.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

W=1 builds now warn if module is built without a MODULE_DESCRIPTION().
Add descriptions to the Qualcom rmnet and emac drivers.
Signed-off-by: Breno Leitao <leitao@debian.org>
Reviewed-by: Subash Abhinov Kasiviswanathan <quic_subashab@quicinc.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

W=1 builds now warn if module is built without a MODULE_DESCRIPTION().
Add descriptions to the SMSC 91x/911x/9420 Ethernet drivers.
Signed-off-by: Breno Leitao <leitao@debian.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

W=1 builds now warn if module is built without a MODULE_DESCRIPTION().
Add descriptions to the Ocelot SoCs (VSC7514) helpers driver.
Signed-off-by: Breno Leitao <leitao@debian.org>
Reviewed-by: Horatiu Vultur <horatiu.vultur@microchip.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

W=1 builds now warn if module is built without a MODULE_DESCRIPTION().
Add descriptions to the Microchip ENCX24J600 helpers driver.
Signed-off-by: Breno Leitao <leitao@debian.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

As of now, the field TCA_TAPRIO_ATTR_FLAGS is being validated by manually
checking its value, using the function taprio_flags_valid().

With this patch, the field will be validated through the netlink policy
NLA_POLICY_MASK, where the mask is defined by TAPRIO_SUPPORTED_FLAGS.
The mutual exclusivity of the two flags TCA_TAPRIO_ATTR_FLAG_FULL_OFFLOAD
and TCA_TAPRIO_ATTR_FLAG_TXTIME_ASSIST is still checked manually.

Changes since RFC:
- fixed reversed xmas tree
- use NL_SET_ERR_MSG_MOD() for both invalid configuration

Changes since v1:
- Changed NL_SET_ERR_MSG_MOD to NL_SET_ERR_MSG_ATTR when wrong flags
  issued
- Changed __u32 to u32

Changes since v2:
- Added the missing parameter for NL_SET_ERR_MSG_ATTR (sorry again for
  the noise)
Signed-off-by: Alessandro Marcolini <alessandromarcolini99@gmail.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>