samples: bpf: Refactor kprobe tracing programs with libbpf

For the problem of increasing fragmentation of the bpf loader programs,
instead of using bpf_loader.o, which is used in samples/bpf, this
commit refactors the existing kprobe tracing programs with libbbpf
bpf loader.

- For kprobe events pointing to system calls, the SYSCALL() macro in
trace_common.h was used.
- Adding a kprobe event and attaching a bpf program to it was done
through bpf_program_attach().
- Instead of using the existing BPF MAP definition, MAP definition
has been refactored with the new BTF-defined MAP format.

Signed-off-by: Daniel T. Lee <danieltimlee@gmail.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200823085334.9413-3-danieltimlee@gmail.com

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 206

Based on 1 normalized pattern(s):

this program is free software you can redistribute it and or modify
it under the terms of version 2 of the gnu general public license as
published by the free software foundation

extracted by the scancode license scanner the SPDX license identifier

GPL-2.0-only

has been chosen to replace the boilerplate/reference in 107 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Allison Randal <allison@lohutok.net>
Reviewed-by: Richard Fontana <rfontana@redhat.com>
Reviewed-by: Steve Winslow <swinslow@gmail.com>
Reviewed-by: Alexios Zavras <alexios.zavras@intel.com>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190528171438.615055994@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

samples: bpf: include bpf/bpf.h instead of local libbpf.h

There are two files in the tree called libbpf.h which is becoming
problematic. Most samples don't actually need the local libbpf.h
they simply include it to get to bpf/bpf.h. Include bpf/bpf.h
directly instead.

Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Acked-by: Jesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

samples/bpf: Make samples more libbpf-centric

Switch all of the sample code to use the function names from
tools/lib/bpf so that they're consistent with that, and to declare their
own log buffers. This allow the next commit to be purely devoted to
getting rid of the duplicate library in samples/bpf.

Committer notes:

Testing it:

On a fedora rawhide container, with clang/llvm 3.9, sharing the host
linux kernel git tree:

# make O=/tmp/build/linux/ headers_install
# make O=/tmp/build/linux -C samples/bpf/

Since I forgot to make it privileged, just tested it outside the
container, using what it generated:

# uname -a
Linux jouet 4.9.0-rc8+ #1 SMP Mon Dec 12 11:20:49 BRT 2016 x86_64 x86_64 x86_64 GNU/Linux
# cd /var/lib/docker/devicemapper/mnt/c43e09a53ff56c86a07baf79847f00e2cc2a17a1e2220e1adbf8cbc62734feda/rootfs/tmp/build/linux/samples/bpf/
# ls -la offwaketime
-rwxr-xr-x. 1 root root 24200 Dec 15 12:19 offwaketime
# file offwaketime
offwaketime: ELF 64-bit LSB executable, x86-64, version 1 (SYSV), dynamically linked, interpreter /lib64/ld-linux-x86-64.so.2, for GNU/Linux 2.6.32, BuildID[sha1]=c940d3f127d5e66cdd680e42d885cb0b64f8a0e4, not stripped
# readelf -SW offwaketime_kern.o | grep PROGBITS
[ 2] .text PROGBITS 0000000000000000 000040 000000 00 AX 0 0 4
[ 3] kprobe/try_to_wake_up PROGBITS 0000000000000000 000040 0000d8 00 AX 0 0 8
[ 5] tracepoint/sched/sched_switch PROGBITS 0000000000000000 000118 000318 00 AX 0 0 8
[ 7] maps PROGBITS 0000000000000000 000430 000050 00 WA 0 0 4
[ 8] license PROGBITS 0000000000000000 000480 000004 00 WA 0 0 1
[ 9] version PROGBITS 0000000000000000 000484 000004 00 WA 0 0 4
# ./offwaketime | head -5
swapper/1;start_secondary;cpu_startup_entry;schedule_preempt_disabled;schedule;__schedule;-;---;; 106
CPU 0/KVM;entry_SYSCALL_64_fastpath;sys_ioctl;do_vfs_ioctl;kvm_vcpu_ioctl;kvm_arch_vcpu_ioctl_run;kvm_vcpu_block;schedule;__schedule;-;try_to_wake_up;swake_up_locked;swake_up;apic_timer_expired;apic_timer_fn;__hrtimer_run_queues;hrtimer_interrupt;local_apic_timer_interrupt;smp_apic_timer_interrupt;__irqentry_text_start;cpuidle_enter;call_cpuidle;cpu_startup_entry;start_secondary;;swapper/3 2
Compositor;entry_SYSCALL_64_fastpath;sys_futex;do_futex;futex_wait;futex_wait_queue_me;schedule;__schedule;-;try_to_wake_up;futex_requeue;do_futex;sys_futex;entry_SYSCALL_64_fastpath;;SoftwareVsyncTh 5
firefox;entry_SYSCALL_64_fastpath;sys_poll;do_sys_poll;poll_schedule_timeout;schedule_hrtimeout_range;schedule_hrtimeout_range_clock;schedule;__schedule;-;try_to_wake_up;pollwake;__wake_up_common;__wake_up_sync_key;pipe_write;__vfs_write;vfs_write;sys_write;entry_SYSCALL_64_fastpath;;Timer 13
JS Helper;entry_SYSCALL_64_fastpath;sys_futex;do_futex;futex_wait;futex_wait_queue_me;schedule;__schedule;-;try_to_wake_up;do_futex;sys_futex;entry_SYSCALL_64_fastpath;;firefox 2
#

Signed-off-by: Joe Stringer <joe@ovn.org>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Alexei Starovoitov <ast@fb.com>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Wang Nan <wangnan0@huawei.com>
Cc: netdev@vger.kernel.org
Link: http://lkml.kernel.org/r/20161214224342.12858-2-joe@ovn.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

bpf: BPF based latency tracing

BPF offers another way to generate latency histograms. We attach
kprobes at trace_preempt_off and trace_preempt_on and calculate the
time it takes to from seeing the off/on transition.

The first array is used to store the start time stamp. The key is the
CPU id. The second array stores the log2(time diff). We need to use
static allocation here (array and not hash tables). The kprobes
hooking into trace_preempt_on|off should not calling any dynamic
memory allocation or free path. We need to avoid recursivly
getting called. Besides that, it reduces jitter in the measurement.

CPU 0
latency : count distribution
1 -> 1 : 0 | |
2 -> 3 : 0 | |
4 -> 7 : 0 | |
8 -> 15 : 0 | |
16 -> 31 : 0 | |
32 -> 63 : 0 | |
64 -> 127 : 0 | |
128 -> 255 : 0 | |
256 -> 511 : 0 | |
512 -> 1023 : 0 | |
1024 -> 2047 : 0 | |
2048 -> 4095 : 166723 |*************************************** |
4096 -> 8191 : 19870 |*** |
8192 -> 16383 : 6324 | |
16384 -> 32767 : 1098 | |
32768 -> 65535 : 190 | |
65536 -> 131071 : 179 | |
131072 -> 262143 : 18 | |
262144 -> 524287 : 4 | |
524288 -> 1048575 : 1363 | |
CPU 1
latency : count distribution
1 -> 1 : 0 | |
2 -> 3 : 0 | |
4 -> 7 : 0 | |
8 -> 15 : 0 | |
16 -> 31 : 0 | |
32 -> 63 : 0 | |
64 -> 127 : 0 | |
128 -> 255 : 0 | |
256 -> 511 : 0 | |
512 -> 1023 : 0 | |
1024 -> 2047 : 0 | |
2048 -> 4095 : 114042 |*************************************** |
4096 -> 8191 : 9587 |** |
8192 -> 16383 : 4140 | |
16384 -> 32767 : 673 | |
32768 -> 65535 : 179 | |
65536 -> 131071 : 29 | |
131072 -> 262143 : 4 | |
262144 -> 524287 : 1 | |
524288 -> 1048575 : 364 | |
CPU 2
latency : count distribution
1 -> 1 : 0 | |
2 -> 3 : 0 | |
4 -> 7 : 0 | |
8 -> 15 : 0 | |
16 -> 31 : 0 | |
32 -> 63 : 0 | |
64 -> 127 : 0 | |
128 -> 255 : 0 | |
256 -> 511 : 0 | |
512 -> 1023 : 0 | |
1024 -> 2047 : 0 | |
2048 -> 4095 : 40147 |*************************************** |
4096 -> 8191 : 2300 |* |
8192 -> 16383 : 828 | |
16384 -> 32767 : 178 | |
32768 -> 65535 : 59 | |
65536 -> 131071 : 2 | |
131072 -> 262143 : 0 | |
262144 -> 524287 : 1 | |
524288 -> 1048575 : 174 | |
CPU 3
latency : count distribution
1 -> 1 : 0 | |
2 -> 3 : 0 | |
4 -> 7 : 0 | |
8 -> 15 : 0 | |
16 -> 31 : 0 | |
32 -> 63 : 0 | |
64 -> 127 : 0 | |
128 -> 255 : 0 | |
256 -> 511 : 0 | |
512 -> 1023 : 0 | |
1024 -> 2047 : 0 | |
2048 -> 4095 : 29626 |*************************************** |
4096 -> 8191 : 2704 |** |
8192 -> 16383 : 1090 | |
16384 -> 32767 : 160 | |
32768 -> 65535 : 72 | |
65536 -> 131071 : 32 | |
131072 -> 262143 : 26 | |
262144 -> 524287 : 12 | |
524288 -> 1048575 : 298 | |

All this is based on the trace3 examples written by
Alexei Starovoitov <ast@plumgrid.com>.

Signed-off-by: Daniel Wagner <daniel.wagner@bmw-carit.de>
Cc: Alexei Starovoitov <ast@plumgrid.com>
Cc: Alexei Starovoitov <ast@plumgrid.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: linux-kernel@vger.kernel.org
Cc: netdev@vger.kernel.org
Acked-by: Alexei Starovoitov <ast@plumgrid.com>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: David S. Miller <davem@davemloft.net>