ndo_xsk_wakeup() can return -ENETDOWN and there's no particular reason
to bail the whole application out on that case. Let's check in kick_tx()
whether errno was set to mentioned value and basically allow application
to further process frames.

Fixes: 248c7f9c ("samples/bpf: convert xdpsock to use libbpf for AF_XDP access")
Reported-by: Cameron Elliott <cameron@cameronelliott.com>
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/20200205045834.56795-4-maciej.fijalkowski@intel.com

Seems that by accident there is a doubled declaration of global variable
opt_xdp_bind_flags in xdpsock_user.c. The second one is uninitialized so
compiler was simply ignoring it.

To keep things clean, drop the doubled variable.

Fixes: c543f546 ("samples/bpf: add unaligned chunks mode support to xdpsock")
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/20200205045834.56795-3-maciej.fijalkowski@intel.com

The most notable change is DEFINE_SHOW_ATTRIBUTE macro split in
seq_file.h.

Conversion rule is:

	llseek		=> proc_lseek
	unlocked_ioctl	=> proc_ioctl

	xxx		=> proc_xxx

	delete ".owner = THIS_MODULE" line

[akpm@linux-foundation.org: fix drivers/isdn/capi/kcapi_proc.c]
[sfr@canb.auug.org.au: fix kernel/sched/psi.c]
  Link: http://lkml.kernel.org/r/20200122180545.36222f50@canb.auug.org.au
Link: http://lkml.kernel.org/r/20191225172546.GB13378@avx2


Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

In old days, the "host-progs" syntax was used for specifying host
programs. It was renamed to the current "hostprogs-y" in 2004.

It is typically useful in scripts/Makefile because it allows Kbuild to
selectively compile host programs based on the kernel configuration.

This commit renames like follows:

  always       ->  always-y
  hostprogs-y  ->  hostprogs

So, scripts/Makefile will look like this:

  always-$(CONFIG_BUILD_BIN2C) += ...
  always-$(CONFIG_KALLSYMS)    += ...
      ...
  hostprogs := $(always-y) $(always-m)

I think this makes more sense because a host program is always a host
program, irrespective of the kernel configuration. We want to specify
which ones to compile by CONFIG options, so always-y will be handier.

The "always", "hostprogs-y", "hostprogs-m" will be kept for backward
compatibility for a while.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

The code in the 'samples' subdirectory isn't part of the kernel, so
there's no need to validate it.

Reported-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/c4cb4ef635ec606454ab834cb49fc3e9381fb1b1.1579543924.git.jpoimboe@redhat.com

Fix all files in samples/bpf to include libbpf header files with the bpf/
prefix, to be consistent with external users of the library. Also ensure
that all includes of exported libbpf header files (those that are exported
on 'make install' of the library) use bracketed includes instead of quoted.

To make sure no new files are introduced that doesn't include the bpf/
prefix in its include, remove tools/lib/bpf from the include path entirely,
and use tools/lib instead.

Fixes: 6910d7d3 ("selftests/bpf: Ensure bpf_helper_defs.h are taken from selftests dir")
Signed-off-by: Toke Høiland-Jørgensen <toke@redhat.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Jesper Dangaard Brouer <brouer@redhat.com>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Link: https://lore.kernel.org/bpf/157952560911.1683545.8795966751309534150.stgit@toke.dk

The 'clean' rule in the samples/bpf Makefile tries to remove backup
files (ending in ~). However, if no such files exist, it will instead try
to remove the user's home directory. While the attempt is mostly harmless,
it does lead to a somewhat scary warning like this:

rm: cannot remove '~': Is a directory

Fix this by using find instead of shell expansion to locate any actual
backup files that need to be removed.

Fixes: b62a796c ("samples/bpf: allow make to be run from samples/bpf/ directory")
Signed-off-by: Toke Høiland-Jørgensen <toke@redhat.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Jesper Dangaard Brouer <brouer@redhat.com>
Link: https://lore.kernel.org/bpf/157952560126.1683545.7273054725976032511.stgit@toke.dk

klp_shadow_alloc() is not handled in the sample of shadow variable API.
It is not strictly necessary because livepatch_fix1_dummy_free() is
able to handle the potential failure. But it is an example and it should
use the API a clean way.

Signed-off-by: Petr Mladek <pmladek@suse.com>
Reviewed-by: Joe Lawrence <joe.lawrence@redhat.com>
Acked-by: Miroslav Benes <mbenes@suse.cz>
Reviewed-by: Kamalesh Babulal <kamalesh@linux.vnet.ibm.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

The commit e91c2518 ("livepatch: Initialize shadow variables
safely by a custom callback") leads to the following static checker
warning:

  samples/livepatch/livepatch-shadow-fix1.c:86 livepatch_fix1_dummy_alloc()
  error: 'klp_shadow_alloc()' 'leak' too small (4 vs 8)

It is because klp_shadow_alloc() is used a wrong way:

  int *leak;
  shadow_leak = klp_shadow_alloc(d, SV_LEAK, sizeof(leak), GFP_KERNEL,
				 shadow_leak_ctor, leak);

The code is supposed to store the "leak" pointer into the shadow variable.
3rd parameter correctly passes size of the data (size of pointer). But
the 5th parameter is wrong. It should pass pointer to the data (pointer
to the pointer) but it passes the pointer directly.

It works because shadow_leak_ctor() handle "ctor_data" as the data
instead of pointer to the data. But it is semantically wrong and
confusing.

The same problem is also in the module used by selftests. In this case,
"pvX" variables are introduced. They represent the data stored in
the shadow variables.

Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
Reviewed-by: Joe Lawrence <joe.lawrence@redhat.com>
Acked-by: Miroslav Benes <mbenes@suse.cz>
Reviewed-by: Kamalesh Babulal <kamalesh@linux.vnet.ibm.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

The "leak" pointer, in the sample of shadow variable API, is allocated
as sizeof(int). Let's help developers and static analyzers with
understanding the code by using the appropriate pointer type.

Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
Reviewed-by: Joe Lawrence <joe.lawrence@redhat.com>
Acked-by: Miroslav Benes <mbenes@suse.cz>
Reviewed-by: Kamalesh Babulal <kamalesh@linux.vnet.ibm.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

Now that we don't have a reference to a devmap when flushing the device
bulk queue, let's change the the devmap_xmit tracepoint to remote the
map_id and map_index fields entirely. Rearrange the fields so 'drops' and
'sent' stay in the same position in the tracepoint struct, to make it
possible for the xdp_monitor utility to read both the old and the new
format.

Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: Toke Høiland-Jørgensen <toke@redhat.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/157918768613.1458396.9165902403373826572.stgit@toke.dk

The sizes by which seccomp_notif and seccomp_notif_resp are allocated are
based on the SECCOMP_GET_NOTIF_SIZES ioctl. This allows for graceful
extension of these datastructures. If userspace zeroes out the
datastructure based on its version, and it is lagging behind the kernel's
version, it will end up sending trailing garbage. On the other hand,
if it is ahead of the kernel version, it will write extra zero space,
and potentially cause corruption.

Signed-off-by: Sargun Dhillon <sargun@sargun.me>
Suggested-by: Tycho Andersen <tycho@tycho.ws>
Link: https://lore.kernel.org/r/20191230203503.4925-1-sargun@sargun.me


Fixes: fec7b669 ("samples: add an example of seccomp user trap")
Cc: stable@vger.kernel.org
Signed-off-by: Kees Cook <keescook@chromium.org>

trace_printk schedules work via irq_work_queue(), but doesn't
wait until it was processed. The kprobe_module.tc testcase does:

:;: "Load module again, which means the event1 should be recorded";:
modprobe trace-printk
grep "event1:" trace

so the grep which checks the trace file might run before the irq work
was processed. Fix this by adding a irq_work_sync().

Link: http://lore.kernel.org/linux-trace-devel/20191218074427.96184-3-svens@linux.ibm.com



Cc: stable@vger.kernel.org
Fixes: af2a0750 ("selftests/ftrace: Improve kprobe on module testcase to load/unload module")
Signed-off-by: Sven Schnelle <svens@linux.ibm.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

When sample xdp_redirect_cpu was converted to use libbpf, the
tracepoints used by this sample were not getting attached automatically
like with bpf_load.c. The BPF-maps was still getting loaded, thus
nobody notice that the tracepoints were not updating these maps.

This fix doesn't use the new skeleton code, as this bug was introduced
in v5.1 and stable might want to backport this. E.g. Red Hat QA uses
this sample as part of their testing.

Fixes: bbaf6029 ("samples/bpf: Convert XDP samples to libbpf usage")
Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Link: https://lore.kernel.org/bpf/157685877642.26195.2798780195186786841.stgit@firesoul

The UDP payload fill pattern can be specified using '-P' or '--tx-pkt-pattern'
option. It is an unsigned 32 bit field and defaulted to 0x12345678.

The IP and UDP checksum is calculated by the code as per the content of
the packet before transmission.

Signed-off-by: Jay Jayatheerthan <jay.jayatheerthan@intel.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20191220085530.4980-7-jay.jayatheerthan@intel.com

New option '-s' or '--tx-pkt-size' has been added to specify the transmit
packet size. The packet size ranges from 47 to 4096 bytes. When this
option is not provided, it defaults to 64 byte packet.

The code uses struct ethhdr, struct iphdr and struct udphdr to form the
transmit packet. The MAC address, IP address and UDP ports are set to default
values.

The code calculates IP and UDP checksums before sending the packet.
Checksum calculation code in Linux kernel is used for this purpose.
The Ethernet FCS is not filled by the code.

Signed-off-by: Jay Jayatheerthan <jay.jayatheerthan@intel.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20191220085530.4980-6-jay.jayatheerthan@intel.com

Use '-C' or '--tx-pkt-count' to specify number of packets to send.
If it is not specified, the application sends packets forever. If packet
count is not a multiple of batch size, last batch sent is less than the
batch size.

Signed-off-by: Jay Jayatheerthan <jay.jayatheerthan@intel.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20191220085530.4980-5-jay.jayatheerthan@intel.com

New option to specify batch size for tx, rx and l2fwd has been added. This
allows fine tuning to maximize performance. It is specified using '-b' or
'--batch_size' options. When not specified default is 64.

Signed-off-by: Jay Jayatheerthan <jay.jayatheerthan@intel.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20191220085530.4980-4-jay.jayatheerthan@intel.com

Add code to do cleanup for signals and application completion in a unified
fashion. The signal handler sets benckmark_done flag terminating the
threads. The cleanup is called before returning from main() function.

Signed-off-by: Jay Jayatheerthan <jay.jayatheerthan@intel.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20191220085530.4980-3-jay.jayatheerthan@intel.com

The application now supports '-d' or '--duration' option to specify number of
seconds to run. This is used in tx, rx and l2fwd features. If this option is
not provided, the application runs forever.

Signed-off-by: Jay Jayatheerthan <jay.jayatheerthan@intel.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20191220085530.4980-2-jay.jayatheerthan@intel.com

When attaching XDP programs, userspace can set flags to request the attach
mode (generic/SKB mode, driver mode or hw offloaded mode). If no such flags
are requested, the kernel will attempt to attach in driver mode, and then
silently fall back to SKB mode if this fails.

The silent fallback is a major source of user confusion, as users will try
to load a program on a device without XDP support, and instead of an error
they will get the silent fallback behaviour, not notice, and then wonder
why performance is not what they were expecting.

In an attempt to combat this, let's switch all the samples to default to
explicitly requesting driver-mode attach. As part of this, ensure that all
the userspace utilities have a switch to enable SKB mode. For those that
have a switch to request driver mode, keep it but turn it into a no-op.

Signed-off-by: Toke Høiland-Jørgensen <toke@redhat.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Jesper Dangaard Brouer <brouer@redhat.com>
Acked-by: David Ahern <dsahern@gmail.com>
Link: https://lore.kernel.org/bpf/20191216110742.364456-1-toke@redhat.com

It seems Clang can in some cases turn on stack protection by default, which
doesn't work with BPF. This was reported once before[0], but it seems the
flag to explicitly turn off the stack protector wasn't added to the
Makefile, so do that now.

The symptom of this is compile errors like the following:

error: <unknown>:0:0: in function bpf_prog1 i32 (%struct.__sk_buff*): A call to built-in function '__stack_chk_fail' is not supported.

[0] https://www.spinics.net/lists/netdev/msg556400.html



Signed-off-by: Toke Høiland-Jørgensen <toke@redhat.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20191216103819.359535-1-toke@redhat.com

Since libbpf now links against zlib, this needs to be included in the
linker invocation for the userspace programs in samples/bpf that link
statically against libbpf.

Fixes: 166750bc ("libbpf: Support libbpf-provided extern variables")
Signed-off-by: Toke Høiland-Jørgensen <toke@redhat.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Tested-by: Björn Töpel <bjorn.topel@intel.com>
Link: https://lore.kernel.org/bpf/20191216102405.353834-1-toke@redhat.com

Add xdp_redirect and per_socket_stats_example in build targets.
They got removed from build targets in Makefile reorganization.

Fixes: 1d97c6c2 ("samples/bpf: Base target programs rules on Makefile.target")
Signed-off-by: Prashant Bhole <prashantbhole.linux@gmail.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20191216071619.25479-1-prashantbhole.linux@gmail.com

Currently, open() is called from the user program and it calls the syscall
'sys_openat', not the 'sys_open'. This leads to an error of the program
of user side, due to the fact that the counter maps are zero since no
function such 'sys_open' is called.

This commit adds the kernel bpf program which are attached to the
tracepoint 'sys_enter_openat' and 'sys_enter_openat'.

Fixes: 1da236b6 ("bpf: add a test case for syscalls/sys_{enter|exit}_* tracepoints")
Signed-off-by: Daniel T. Lee <danieltimlee@gmail.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

Previously, when this sample is added, commit 1c47910e
("samples/bpf: add perf_event+bpf example"), a symbol 'sys_read' and
'sys_write' has been used without no prefixes. But currently there are
no exact symbols with these under kallsyms and this leads to failure.

This commit changes exact compare to substring compare to keep compatible
with exact symbol or prefixed symbol.

Fixes: 1c47910e ("samples/bpf: add perf_event+bpf example")
Signed-off-by: Daniel T. Lee <danieltimlee@gmail.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20191205080114.19766-2-danieltimlee@gmail.com

Now that the fbops member of struct fb_info is const, we can start
making the ops const as well.

v2: fix typo (Christophe de Dinechin)

Cc: Kirti Wankhede <kwankhede@nvidia.com>
Cc: kvm@vger.kernel.org
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Acked-by: Kirti Wankhede <kwankhede@nvidia.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/ddb10df1316ef585930cda7718643a580f4fe37b.1575390741.git.jani.nikula@intel.com

In the days of using bpf_load.c the order in which the 'maps' sections
were defines in BPF side (*_kern.c) file, were used by userspace side
to identify the map via using the map order as an index. In effect the
order-index is created based on the order the maps sections are stored
in the ELF-object file, by the LLVM compiler.

This have also carried over in libbpf via API bpf_map__next(NULL, obj)
to extract maps in the order libbpf parsed the ELF-object file.

When BTF based maps were introduced a new section type ".maps" were
created. I found that the LLVM compiler doesn't create the ".maps"
sections in the order they are defined in the C-file. The order in the
ELF file is based on the order the map pointer is referenced in the code.

This combination of changes lead to xdp_rxq_info mixing up the map
file-descriptors in userspace, resulting in very broken behaviour, but
without warning the user.

This patch fix issue by instead using bpf_object__find_map_by_name()
to find maps via their names. (Note, this is the ELF name, which can
be longer than the name the kernel retains).

Fixes: be5bca44 ("samples: bpf: convert some XDP samples from bpf_load to libbpf")
Fixes: 451d1dc8 ("samples: bpf: update map definition to new syntax BTF-defined map")
Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Toke Høiland-Jørgensen <toke@redhat.com>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Link: https://lore.kernel.org/bpf/157529025128.29832.5953245340679936909.stgit@firesoul

No in-tree users left.

Acked-by: Sumit Semwal <sumit.semwal@linaro.org>
Acked-by: Gerd Hoffmann <kraxel@redhat.com>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Cc: Kirti Wankhede <kwankhede@nvidia.com>
Cc: kvm@vger.kernel.org
Link: https://patchwork.freedesktop.org/patch/msgid/20191118103536.17675-15-daniel.vetter@ffwll.ch

This is a sample module to demonstrate the use of the newly introduced and
exported APIs to access Ftrace instances from within the kernel.

Newly introduced APIs used here -

1. Create/Lookup a trace array with the given name.
struct trace_array *trace_array_get_by_name(const char *name)

2. Destroy/Remove a trace array.
int trace_array_destroy(struct trace_array *tr)

4. Enable/Disable trace events:
int trace_array_set_clr_event(struct trace_array *tr, const char *system,
        const char *event, bool enable);

Exported APIs -
1. trace_printk equivalent for instances.
int trace_array_printk(struct trace_array *tr,
               unsigned long ip, const char *fmt, ...);

2. Helper function.
void trace_printk_init_buffers(void);

3. To decrement the reference counter.
void trace_array_put(struct trace_array *tr)

Sample output(contents of /sys/kernel/tracing/instances/sample-instance)
NOTE: Tracing disabled after ~5 sec)

                              _-----=> irqs-off
                             / _----=> need-resched
                            | / _---=> hardirq/softirq
                            || / _--=> preempt-depth
                            ||| /     delay
           TASK-PID   CPU#  ||||    TIMESTAMP  FUNCTION
              | |       |   ||||       |         |
sample-instance-1452  [002] ....    49.430948: simple_thread: trace_array_printk: count=0
sample-instance-1452  [002] ....    49.430951: sample_event: count value=0 at jiffies=4294716608
sample-instance-1452  [002] ....    50.454847: simple_thread: trace_array_printk: count=1
sample-instance-1452  [002] ....    50.454849: sample_event: count value=1 at jiffies=4294717632
sample-instance-1452  [002] ....    51.478748: simple_thread: trace_array_printk: count=2
sample-instance-1452  [002] ....    51.478750: sample_event: count value=2 at jiffies=4294718656
sample-instance-1452  [002] ....    52.502652: simple_thread: trace_array_printk: count=3
sample-instance-1452  [002] ....    52.502655: sample_event: count value=3 at jiffies=4294719680
sample-instance-1452  [002] ....    53.526533: simple_thread: trace_array_printk: count=4
sample-instance-1452  [002] ....    53.526535: sample_event: count value=4 at jiffies=4294720704
sample-instance-1452  [002] ....    54.550438: simple_thread: trace_array_printk: count=5
sample-instance-1452  [002] ....    55.574336: simple_thread: trace_array_printk: count=6

Link: http://lkml.kernel.org/r/1574276919-11119-3-git-send-email-divya.indi@oracle.com



Reviewed-by: Aruna Ramakrishna <aruna.ramakrishna@oracle.com>
Signed-off-by: Divya Indi <divya.indi@oracle.com>
[ Moved to samples/ftrace ]
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

Commit 743e568c (samples/bpf: Add a "force" flag to XDP samples)
introduced the '-F' option but missed adding it to the usage() and the
'long_option' array.

Fixes: 743e568c (samples/bpf: Add a "force" flag to XDP samples)
Signed-off-by: Andre Guedes <andre.guedes@intel.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20191114162847.221770-2-andre.guedes@intel.com

The '-f' option is shown twice in the usage(). This patch removes the
outdated version.

Signed-off-by: Andre Guedes <andre.guedes@intel.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20191114162847.221770-1-andre.guedes@intel.com

There is a spelling mistake in a trace_printk message. As well as in
the selftests that search for this string.

Link: http://lkml.kernel.org/r/20191115085938.38947-1-colin.king@canonical.com
Link: http://lkml.kernel.org/r/20191115090356.39572-1-colin.king@canonical.com



Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

Add a sample module that tests modify_ftrace_direct(), and this can be used
by the selftests as well.

Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

Add another module sample that registers a direct trampoline to a function
via register_ftrace_direct(). Having another module that does this allows to
test the use case of multiple direct callers registered, as more than one
direct caller goes into another path, and is needed to perform proper
testing of the register_ftrace_direct() call.

Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

Add a sample module that shows a simple use case for
regsiter_ftrace_direct(), and how to use it.

Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

Side effect of some kbuild changes resulted in breaking the
documented way to build samples/bpf/.

This patch change the samples/bpf/Makefile to work again, when
invoking make from the subdir samples/bpf/. Also update the
documentation in README.rst, to reflect the new way to build.

Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

Use Rx-only sockets for the rxdrop sample and Tx-only sockets for the
txpush sample in the xdpsock application. This so that we exercise and
show case these socket types too.

Signed-off-by: Magnus Karlsson <magnus.karlsson@intel.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Tested-by: William Tu <u9012063@gmail.com>
Acked-by: Jonathan Lemon <jonathan.lemon@gmail.com>
Link: https://lore.kernel.org/bpf/1573148860-30254-5-git-send-email-magnus.karlsson@intel.com

Add support for the XDP_SHARED_UMEM mode to the xdpsock sample
application. As libbpf does not have a built in XDP program for this
mode, we use an explicitly loaded XDP program. This also serves as an
example on how to write your own XDP program that can route to an
AF_XDP socket.

Signed-off-by: Magnus Karlsson <magnus.karlsson@intel.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Tested-by: William Tu <u9012063@gmail.com>
Acked-by: Jonathan Lemon <jonathan.lemon@gmail.com>
Link: https://lore.kernel.org/bpf/1573148860-30254-3-git-send-email-magnus.karlsson@intel.com

Since, the new syntax of BTF-defined map has been introduced,
the syntax for using maps under samples directory are mixed up.
For example, some are already using the new syntax, and some are using
existing syntax by calling them as 'legacy'.

As stated at commit abd29c93 ("libbpf: allow specifying map
definitions using BTF"), the BTF-defined map has more compatablility
with extending supported map definition features.

The commit doesn't replace all of the map to new BTF-defined map,
because some of the samples still use bpf_load instead of libbpf, which
can't properly create BTF-defined map.

This will only updates the samples which uses libbpf API for loading bpf
program. (ex. bpf_prog_load_xattr)

Signed-off-by: Daniel T. Lee <danieltimlee@gmail.com>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>