It is not intuitive that 'make' must be run from the top level
directory with argument "samples/bpf/" to compile these eBPF samples.

Introduce a kbuild make file trick that allow make to be run from the
"samples/bpf/" directory itself.  It basically change to the top level
directory and call "make samples/bpf/" with the "/" slash after the
directory name.

Also add a clean target that only cleans this directory, by taking
advantage of the kbuild external module setting M=$PWD.
Signed-off-by: NJesper Dangaard Brouer <brouer@redhat.com>
Acked-by: NAlexei Starovoitov <ast@kernel.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Getting started with using examples in samples/bpf/ is not
straightforward.  There are several dependencies, and specific
versions of these dependencies.

Just compiling the example tool is also slightly obscure, e.g. one
need to call make like:

 make samples/bpf/

Do notice the "/" slash after the directory name.
Signed-off-by: NJesper Dangaard Brouer <brouer@redhat.com>
Acked-by: NNaveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Acked-by: NAlexei Starovoitov <ast@kernel.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Make compiling samples/bpf more user friendly, by detecting if LLVM
compiler tool 'llc' is available, and also detect if the 'bpf' target
is available in this version of LLVM.
Signed-off-by: NJesper Dangaard Brouer <brouer@redhat.com>
Acked-by: NAlexei Starovoitov <ast@kernel.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

It is practical to be-able-to redefine the location of the LLVM
command 'llc', because not all distros have a LLVM version with bpf
target support.  Thus, it is sometimes required to compile LLVM from
source, and sometimes it is not desired to overwrite the distros
default LLVM version.

This feature was removed with 128d1514 ("samples/bpf: Use llc in
PATH, rather than a hardcoded value").

Add this features back. Note that it is possible to redefine the LLC
on the make command like:

 make samples/bpf/ LLC=~/git/llvm/build/bin/llc

Fixes: 128d1514 ("samples/bpf: Use llc in PATH, rather than a hardcoded value")
Signed-off-by: NJesper Dangaard Brouer <brouer@redhat.com>
Acked-by: NAlexei Starovoitov <ast@kernel.org>
Acked-by: NNaveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This adds test cases mostly around ARG_PTR_TO_RAW_STACK to check the
verifier behaviour.

  [...]
  #84 raw_stack: no skb_load_bytes OK
  #85 raw_stack: skb_load_bytes, no init OK
  #86 raw_stack: skb_load_bytes, init OK
  #87 raw_stack: skb_load_bytes, spilled regs around bounds OK
  #88 raw_stack: skb_load_bytes, spilled regs corruption OK
  #89 raw_stack: skb_load_bytes, spilled regs corruption 2 OK
  #90 raw_stack: skb_load_bytes, spilled regs + data OK
  #91 raw_stack: skb_load_bytes, invalid access 1 OK
  #92 raw_stack: skb_load_bytes, invalid access 2 OK
  #93 raw_stack: skb_load_bytes, invalid access 3 OK
  #94 raw_stack: skb_load_bytes, invalid access 4 OK
  #95 raw_stack: skb_load_bytes, invalid access 5 OK
  #96 raw_stack: skb_load_bytes, invalid access 6 OK
  #97 raw_stack: skb_load_bytes, large access OK
  Summary: 98 PASSED, 0 FAILED
Signed-off-by: NDaniel Borkmann <daniel@iogearbox.net>
Acked-by: NAlexei Starovoitov <ast@kernel.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Remove the zero initialization in the sample programs where appropriate.
Note that this is an optimization which is now possible, old programs
still doing the zero initialization are just fine as well. Also, make
sure we don't have padding issues when we don't memset() the entire
struct anymore.
Signed-off-by: NDaniel Borkmann <daniel@iogearbox.net>
Acked-by: NAlexei Starovoitov <ast@kernel.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

the first microbenchmark does
fd=open("/proc/self/comm");
for() {
  write(fd, "test");
}
and on 4 cpus in parallel:
                                      writes per sec
base (no tracepoints, no kprobes)         930k
with kprobe at __set_task_comm()          420k
with tracepoint at task:task_rename       730k

For kprobe + full bpf program manully fetches oldcomm, newcomm via bpf_probe_read.
For tracepint bpf program does nothing, since arguments are copied by tracepoint.

2nd microbenchmark does:
fd=open("/dev/urandom");
for() {
  read(fd, buf);
}
and on 4 cpus in parallel:
                                       reads per sec
base (no tracepoints, no kprobes)         300k
with kprobe at urandom_read()             279k
with tracepoint at random:urandom_read    290k

bpf progs attached to kprobe and tracepoint are noop.
Signed-off-by: NAlexei Starovoitov <ast@kernel.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

modify offwaketime to work with sched/sched_switch tracepoint
instead of kprobe into finish_task_switch
Signed-off-by: NAlexei Starovoitov <ast@kernel.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Recognize "tracepoint/" section name prefix and attach the program
to that tracepoint.
Signed-off-by: NAlexei Starovoitov <ast@kernel.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Add the necessary definitions for building bpf samples on ppc.

Since ppc doesn't store function return address on the stack, modify how
PT_REGS_RET() and PT_REGS_FP() work.

Also, introduce PT_REGS_IP() to access the instruction pointer.

Cc: Alexei Starovoitov <ast@fb.com>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: David S. Miller <davem@davemloft.net>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: NNaveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Acked-by: NAlexei Starovoitov <ast@kernel.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

While at it, remove the generation of .s files and fix some typos in the
related comment.

Cc: Alexei Starovoitov <ast@fb.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: NNaveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Acked-by: NAlexei Starovoitov <ast@kernel.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Building BPF samples is failing with the below error:

samples/bpf/map_perf_test_user.c: In function ‘main’:
samples/bpf/map_perf_test_user.c:134:9: error: variable ‘r’ has
initializer but incomplete type
  struct rlimit r = {RLIM_INFINITY, RLIM_INFINITY};
         ^
samples/bpf/map_perf_test_user.c:134:21: error: ‘RLIM_INFINITY’
undeclared (first use in this function)
  struct rlimit r = {RLIM_INFINITY, RLIM_INFINITY};
                     ^
samples/bpf/map_perf_test_user.c:134:21: note: each undeclared
identifier is reported only once for each function it appears in
samples/bpf/map_perf_test_user.c:134:9: warning: excess elements in
struct initializer [enabled by default]
  struct rlimit r = {RLIM_INFINITY, RLIM_INFINITY};
         ^
samples/bpf/map_perf_test_user.c:134:9: warning: (near initialization
for ‘r’) [enabled by default]
samples/bpf/map_perf_test_user.c:134:9: warning: excess elements in
struct initializer [enabled by default]
samples/bpf/map_perf_test_user.c:134:9: warning: (near initialization
for ‘r’) [enabled by default]
samples/bpf/map_perf_test_user.c:134:16: error: storage size of ‘r’
isn’t known
  struct rlimit r = {RLIM_INFINITY, RLIM_INFINITY};
                ^
samples/bpf/map_perf_test_user.c:139:2: warning: implicit declaration of
function ‘setrlimit’ [-Wimplicit-function-declaration]
  setrlimit(RLIMIT_MEMLOCK, &r);
  ^
samples/bpf/map_perf_test_user.c:139:12: error: ‘RLIMIT_MEMLOCK’
undeclared (first use in this function)
  setrlimit(RLIMIT_MEMLOCK, &r);
            ^
samples/bpf/map_perf_test_user.c:134:16: warning: unused variable ‘r’
[-Wunused-variable]
  struct rlimit r = {RLIM_INFINITY, RLIM_INFINITY};
                ^
make[2]: *** [samples/bpf/map_perf_test_user.o] Error 1

Fix this by including the necessary header file.

Cc: Alexei Starovoitov <ast@fb.com>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: David S. Miller <davem@davemloft.net>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Acked-by: NAlexei Starovoitov <ast@kernel.org>
Signed-off-by: NNaveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

performance tests for hash map and per-cpu hash map
with and without pre-allocation
Signed-off-by: NAlexei Starovoitov <ast@kernel.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

increase stress by also calling bpf_get_stackid() from
various *spin* functions
Signed-off-by: NAlexei Starovoitov <ast@kernel.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

this test calls bpf programs from different contexts:
from inside of slub, from rcu, from pretty much everywhere,
since it kprobes all spin_lock functions.
It stresses the bpf hash and percpu map pre-allocation,
deallocation logic and call_rcu mechanisms.
User space part adding more stress by walking and deleting map elements.

Note that due to nature bpf_load.c the earlier kprobe+bpf programs are
already active while loader loads new programs, creates new kprobes and
attaches them.
Signed-off-by: NAlexei Starovoitov <ast@kernel.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

extend test coveraged to include pre-allocated and run-time alloc maps
Signed-off-by: NAlexei Starovoitov <ast@kernel.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

note old loader is compatible with new kernel.
map_flags are optional
Signed-off-by: NAlexei Starovoitov <ast@kernel.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

move ksym search from offwaketime into library to be reused
in other tests
Signed-off-by: NAlexei Starovoitov <ast@kernel.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

map creation is typically the first one to fail when rlimits are
too low, not enough memory, etc
Make this failure scenario more verbose
Signed-off-by: NAlexei Starovoitov <ast@kernel.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This is simplified version of Brendan Gregg's offwaketime:
This program shows kernel stack traces and task names that were blocked and
"off-CPU", along with the stack traces and task names for the threads that woke
them, and the total elapsed time from when they blocked to when they were woken
up. The combined stacks, task names, and total time is summarized in kernel
context for efficiency.

Example:
$ sudo ./offwaketime | flamegraph.pl > demo.svg
Open demo.svg in the browser as FlameGraph visualization.
Signed-off-by: NAlexei Starovoitov <ast@kernel.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Signed-off-by: NAlexei Starovoitov <ast@kernel.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

A sanity test for BPF_MAP_TYPE_PERCPU_ARRAY
Signed-off-by: NMing Lei <tom.leiming@gmail.com>
Signed-off-by: NAlexei Starovoitov <ast@kernel.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

A sanity test for BPF_MAP_TYPE_PERCPU_HASH.
Signed-off-by: NMartin KaFai Lau <kafai@fb.com>
Signed-off-by: NAlexei Starovoitov <ast@kernel.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

commit 338d4f49
("arm64: kernel: Add support for Privileged Access Never") includes sysreg.h
into futex.h and uaccess.h. But, the inline assembly used by asm/sysreg.h is
incompatible with llvm so it will cause BPF samples build failure for ARM64.
Since sysreg.h is useless for BPF samples, just exclude it from Makefile via
defining __ASM_SYSREG_H.
Signed-off-by: NYang Shi <yang.shi@linaro.org>
Acked-by: NAlexei Starovoitov <ast@kernel.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This patch adds a couple of stand-alone examples on how BPF_OBJ_PIN
and BPF_OBJ_GET commands can be used.

Example with maps:

  # ./fds_example -F /sys/fs/bpf/m -P -m -k 1 -v 42
  bpf: map fd:3 (Success)
  bpf: pin ret:(0,Success)
  bpf: fd:3 u->(1:42) ret:(0,Success)
  # ./fds_example -F /sys/fs/bpf/m -G -m -k 1
  bpf: get fd:3 (Success)
  bpf: fd:3 l->(1):42 ret:(0,Success)
  # ./fds_example -F /sys/fs/bpf/m -G -m -k 1 -v 24
  bpf: get fd:3 (Success)
  bpf: fd:3 u->(1:24) ret:(0,Success)
  # ./fds_example -F /sys/fs/bpf/m -G -m -k 1
  bpf: get fd:3 (Success)
  bpf: fd:3 l->(1):24 ret:(0,Success)

  # ./fds_example -F /sys/fs/bpf/m2 -P -m
  bpf: map fd:3 (Success)
  bpf: pin ret:(0,Success)
  # ./fds_example -F /sys/fs/bpf/m2 -G -m -k 1
  bpf: get fd:3 (Success)
  bpf: fd:3 l->(1):0 ret:(0,Success)
  # ./fds_example -F /sys/fs/bpf/m2 -G -m
  bpf: get fd:3 (Success)

Example with progs:

  # ./fds_example -F /sys/fs/bpf/p -P -p
  bpf: prog fd:3 (Success)
  bpf: pin ret:(0,Success)
  bpf sock:4 <- fd:3 attached ret:(0,Success)
  # ./fds_example -F /sys/fs/bpf/p -G -p
  bpf: get fd:3 (Success)
  bpf: sock:4 <- fd:3 attached ret:(0,Success)

  # ./fds_example -F /sys/fs/bpf/p2 -P -p -o ./sockex1_kern.o
  bpf: prog fd:5 (Success)
  bpf: pin ret:(0,Success)
  bpf: sock:3 <- fd:5 attached ret:(0,Success)
  # ./fds_example -F /sys/fs/bpf/p2 -G -p
  bpf: get fd:3 (Success)
  bpf: sock:4 <- fd:3 attached ret:(0,Success)
Signed-off-by: NDaniel Borkmann <daniel@iogearbox.net>
Acked-by: NAlexei Starovoitov <ast@kernel.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The commit 88920427 ("tracing: Update trace-event-sample with
TRACE_SYSTEM_VAR documentation") changed TRACE_SYSTEM to 'sample-trace',
but didn't make the according change of its name in the comments.

Link: http://lkml.kernel.org/r/1443599650-23680-1-git-send-email-zhang.chunyan@linaro.orgSigned-off-by: NChunyan Zhang <zhang.chunyan@linaro.org>
Signed-off-by: NSteven Rostedt <rostedt@goodmis.org>

Define aarch64 specific registers for building bpf samples correctly.
Signed-off-by: NYang Shi <yang.shi@linaro.org>
Acked-by: NAlexei Starovoitov <ast@kernel.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Performance test and example of bpf_perf_event_output().
kprobe is attached to sys_write() and trivial bpf program streams
pid+cookie into userspace via PERF_COUNT_SW_BPF_OUTPUT event.

Usage:
$ sudo ./bld_x64/samples/bpf/trace_output
recv 2968913 events per sec
Signed-off-by: NAlexei Starovoitov <ast@kernel.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Remove the old show_attribute and store_attribute methods and update
the documentation.  Also replace the two C samples with a single new
one in the proper samples directory where people expect to find it.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

Add new tests samples/bpf/test_verifier:

unpriv: return pointer
  checks that pointer cannot be returned from the eBPF program

unpriv: add const to pointer
unpriv: add pointer to pointer
unpriv: neg pointer
  checks that pointer arithmetic is disallowed

unpriv: cmp pointer with const
unpriv: cmp pointer with pointer
  checks that comparison of pointers is disallowed
  Only one case allowed 'void *value = bpf_map_lookup_elem(..); if (value == 0) ...'

unpriv: check that printk is disallowed
  since bpf_trace_printk is not available to unprivileged

unpriv: pass pointer to helper function
  checks that pointers cannot be passed to functions that expect integers
  If function expects a pointer the verifier allows only that type of pointer.
  Like 1st argument of bpf_map_lookup_elem() must be pointer to map.
  (applies to non-root as well)

unpriv: indirectly pass pointer on stack to helper function
  checks that pointer stored into stack cannot be used as part of key
  passed into bpf_map_lookup_elem()

unpriv: mangle pointer on stack 1
unpriv: mangle pointer on stack 2
  checks that writing into stack slot that already contains a pointer
  is disallowed

unpriv: read pointer from stack in small chunks
  checks that < 8 byte read from stack slot that contains a pointer is
  disallowed

unpriv: write pointer into ctx
  checks that storing pointers into skb->fields is disallowed

unpriv: write pointer into map elem value
  checks that storing pointers into element values is disallowed
  For example:
  int bpf_prog(struct __sk_buff *skb)
  {
    u32 key = 0;
    u64 *value = bpf_map_lookup_elem(&map, &key);
    if (value)
       *value = (u64) skb;
  }
  will be rejected.

unpriv: partial copy of pointer
  checks that doing 32-bit register mov from register containing
  a pointer is disallowed

unpriv: pass pointer to tail_call
  checks that passing pointer as an index into bpf_tail_call
  is disallowed

unpriv: cmp map pointer with zero
  checks that comparing map pointer with constant is disallowed

unpriv: write into frame pointer
  checks that frame pointer is read-only (applies to root too)

unpriv: cmp of frame pointer
  checks that R10 cannot be using in comparison

unpriv: cmp of stack pointer
  checks that Rx = R10 - imm is ok, but comparing Rx is not

unpriv: obfuscate stack pointer
  checks that Rx = R10 - imm is ok, but Rx -= imm is not
Signed-off-by: NAlexei Starovoitov <ast@plumgrid.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Commit 3033f14a ("clone: support passing tls argument via C rather
than pt_regs magic") introduced _do_fork() that allowed to pass @tls
parameter.

The old do_fork() is defined only for architectures that are not ready
to use this way and do not define HAVE_COPY_THREAD_TLS.

Let's use _do_fork() in the kprobe examples to make them work again on
all architectures.
Signed-off-by: NPetr Mladek <pmladek@suse.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Thiago Macieira <thiago.macieira@intel.com>
Cc: Jiri Kosina <jkosina@suse.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Existing bpf_clone_redirect() helper clones skb before redirecting
it to RX or TX of destination netdev.
Introduce bpf_redirect() helper that does that without cloning.

Benchmarked with two hosts using 10G ixgbe NICs.
One host is doing line rate pktgen.
Another host is configured as:
$ tc qdisc add dev $dev ingress
$ tc filter add dev $dev root pref 10 u32 match u32 0 0 flowid 1:2 \
   action bpf run object-file tcbpf1_kern.o section clone_redirect_xmit drop
so it receives the packet on $dev and immediately xmits it on $dev + 1
The section 'clone_redirect_xmit' in tcbpf1_kern.o file has the program
that does bpf_clone_redirect() and performance is 2.0 Mpps

$ tc filter add dev $dev root pref 10 u32 match u32 0 0 flowid 1:2 \
   action bpf run object-file tcbpf1_kern.o section redirect_xmit drop
which is using bpf_redirect() - 2.4 Mpps

and using cls_bpf with integrated actions as:
$ tc filter add dev $dev root pref 10 \
  bpf run object-file tcbpf1_kern.o section redirect_xmit integ_act classid 1
performance is 2.5 Mpps

To summarize:
u32+act_bpf using clone_redirect - 2.0 Mpps
u32+act_bpf using redirect - 2.4 Mpps
cls_bpf using redirect - 2.5 Mpps

For comparison linux bridge in this setup is doing 2.1 Mpps
and ixgbe rx + drop in ip_rcv - 7.8 Mpps
Signed-off-by: NAlexei Starovoitov <ast@plumgrid.com>
Acked-by: NDaniel Borkmann <daniel@iogearbox.net>
Acked-by: NJohn Fastabend <john.r.fastabend@intel.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

There are two improvements in this patch:
 1. Fix the build warnings;
 2. Add function read_trace_pipe() to print the result on
    the screen;

Before this patch, we can get the result through /sys/kernel/de
bug/tracing/trace_pipe and get nothing on the screen.
By applying this patch, the result can be printed on the screen.
  $ ./tracex6
	...
         tracex6-705   [003] d..1   131.428593: : CPU-3   19981414
            sshd-683   [000] d..1   131.428727: : CPU-0   221682321
            sshd-683   [000] d..1   131.428821: : CPU-0   221808766
            sshd-683   [000] d..1   131.428950: : CPU-0   221982984
            sshd-683   [000] d..1   131.429045: : CPU-0   222111851
         tracex6-705   [003] d..1   131.429168: : CPU-3   20757551
            sshd-683   [000] d..1   131.429170: : CPU-0   222281240
            sshd-683   [000] d..1   131.429261: : CPU-0   222403340
            sshd-683   [000] d..1   131.429378: : CPU-0   222561024
	...
Signed-off-by: NKaixu Xia <xiakaixu@huawei.com>
Acked-by: NAlexei Starovoitov <ast@plumgrid.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This is a simple example and shows how to use the new ability
to get the selected Hardware PMU counter value.
Signed-off-by: NKaixu Xia <xiakaixu@huawei.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

mov %rsp, %r1           ; r1 = rsp
        add $-8, %r1            ; r1 = rsp - 8
        store_q $123, -8(%rsp)  ; *(u64*)r1 = 123  <- valid
        store_q $123, (%r1)     ; *(u64*)r1 = 123  <- previously invalid
        mov $0, %r0
        exit                    ; Always need to exit

And we'd get the following error:

	0: (bf) r1 = r10
	1: (07) r1 += -8
	2: (7a) *(u64 *)(r10 -8) = 999
	3: (7a) *(u64 *)(r1 +0) = 999
	R1 invalid mem access 'fp'

	Unable to load program

We already know that a register is a stack address and the appropriate
offset, so we should be able to validate those references as well.
Signed-off-by: NAlex Gartrell <agartrell@fb.com>
Acked-by: NAlexei Starovoitov <ast@plumgrid.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

He Kuang noticed that the trace event samples for arrays was broken:

"The output result of trace_foo_bar event in traceevent samples is
 wrong. This problem can be reproduced as following:

  (Build kernel with SAMPLE_TRACE_EVENTS=m)

  $ insmod trace-events-sample.ko

  $ echo 1 > /sys/kernel/debug/tracing/events/sample-trace/foo_bar/enable

  $ cat /sys/kernel/debug/tracing/trace

  event-sample-980 [000] ....  43.649559: foo_bar: foo hello 21 0x15
  BIT1|BIT3|0x10 {0x1,0x6f6f6e53,0xff007970,0xffffffff} Snoopy
                 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
                 The array length is not right, should be {0x1}.
  (ffffffff,ffffffff)

  event-sample-980 [000] ....  44.653827: foo_bar: foo hello 22 0x16
  BIT2|BIT3|0x10
  {0x1,0x2,0x646e6147,0x666c61,0xffffffff,0xffffffff,0x750aeffe,0x7}
  ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
                 The array length is not right, should be {0x1,0x2}.
  Gandalf (ffffffff,ffffffff)"

This was caused by an update to have __print_array()'s second parameter
be the count of items in the array and not the size of the array.

As there is already users of __print_array(), it can not change. But
the sample code can and we can also improve on the documentation about
__print_array() and __get_dynamic_array_len().

Link: http://lkml.kernel.org/r/1436839171-31527-2-git-send-email-hekuang@huawei.com

Fixes: ac01ce14 ("tracing: Make ftrace_print_array_seq compute buf_len")
Reported-by: NHe Kuang <hekuang@huawei.com>
Signed-off-by: NSteven Rostedt <rostedt@goodmis.org>

The trace bpf samples do not compile on s390x because they use x86
specific fields from the "pt_regs" structure.

Fix this and access the fields via new PT_REGS macros.
Signed-off-by: NMichael Holzheu <holzheu@linux.vnet.ibm.com>
Acked-by: NAlexei Starovoitov <ast@plumgrid.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

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: NDaniel 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: NAlexei Starovoitov <ast@plumgrid.com>
Acked-by: NDaniel Borkmann <daniel@iogearbox.net>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

eBPF programs attached to kprobes need to filter based on
current->pid, uid and other fields, so introduce helper functions:

u64 bpf_get_current_pid_tgid(void)
Return: current->tgid << 32 | current->pid

u64 bpf_get_current_uid_gid(void)
Return: current_gid << 32 | current_uid

bpf_get_current_comm(char *buf, int size_of_buf)
stores current->comm into buf

They can be used from the programs attached to TC as well to classify packets
based on current task fields.

Update tracex2 example to print histogram of write syscalls for each process
instead of aggregated for all.
Signed-off-by: NAlexei Starovoitov <ast@plumgrid.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

allow programs read/write skb->mark, tc_index fields and
((struct qdisc_skb_cb *)cb)->data.

mark and tc_index are generically useful in TC.
cb[0]-cb[4] are primarily used to pass arguments from one
program to another called via bpf_tail_call() which can
be seen in sockex3_kern.c example.

All fields of 'struct __sk_buff' are readable to socket and tc_cls_act progs.
mark, tc_index are writeable from tc_cls_act only.
cb[0]-cb[4] are writeable by both sockets and tc_cls_act.

Add verifier tests and improve sample code.
Signed-off-by: NAlexei Starovoitov <ast@plumgrid.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>