Test the following narrow loads in test_verifier for context __sk_buff:
* off=1, size=1 - ok;
* off=2, size=1 - ok;
* off=3, size=1 - ok;
* off=0, size=2 - ok;
* off=1, size=2 - fail;
* off=0, size=2 - ok;
* off=3, size=2 - fail.
Signed-off-by: NAndrey Ignatov <rdna@fb.com>
Signed-off-by: NAlexei Starovoitov <ast@kernel.org>

This commit adds support for loading/attaching/detaching flow
dissector program.

When `bpftool loadall` is called with a flow_dissector prog (i.e. when the
'type flow_dissector' argument is passed), we load and pin all programs.
User is responsible to construct the jump table for the tail calls.

The last argument of `bpftool attach` is made optional for this use
case.

Example:
bpftool prog load tools/testing/selftests/bpf/bpf_flow.o \
        /sys/fs/bpf/flow type flow_dissector \
	pinmaps /sys/fs/bpf/flow

bpftool map update pinned /sys/fs/bpf/flow/jmp_table \
        key 0 0 0 0 \
        value pinned /sys/fs/bpf/flow/IP

bpftool map update pinned /sys/fs/bpf/flow/jmp_table \
        key 1 0 0 0 \
        value pinned /sys/fs/bpf/flow/IPV6

bpftool map update pinned /sys/fs/bpf/flow/jmp_table \
        key 2 0 0 0 \
        value pinned /sys/fs/bpf/flow/IPV6OP

bpftool map update pinned /sys/fs/bpf/flow/jmp_table \
        key 3 0 0 0 \
        value pinned /sys/fs/bpf/flow/IPV6FR

bpftool map update pinned /sys/fs/bpf/flow/jmp_table \
        key 4 0 0 0 \
        value pinned /sys/fs/bpf/flow/MPLS

bpftool map update pinned /sys/fs/bpf/flow/jmp_table \
        key 5 0 0 0 \
        value pinned /sys/fs/bpf/flow/VLAN

bpftool prog attach pinned /sys/fs/bpf/flow/flow_dissector flow_dissector

Tested by using the above lines to load the prog in
the test_flow_dissector.sh selftest.
Signed-off-by: NStanislav Fomichev <sdf@google.com>
Acked-by: NJakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: NAlexei Starovoitov <ast@kernel.org>

This new additional argument lets users pin all maps from the object at
specified path.
Signed-off-by: NStanislav Fomichev <sdf@google.com>
Acked-by: NJakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: NAlexei Starovoitov <ast@kernel.org>

This patch adds new *loadall* command which slightly differs from the
existing *load*. *load* command loads all programs from the obj file,
but pins only the first programs. *loadall* pins all programs from the
obj file under specified directory.

The intended usecase is flow_dissector, where we want to load a bunch
of progs, pin them all and after that construct a jump table.
Signed-off-by: NStanislav Fomichev <sdf@google.com>
Acked-by: NJakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: NAlexei Starovoitov <ast@kernel.org>

pin_name is the same as section_name where '/' is replaced
by '_'. bpf_object__pin_programs is converted to use pin_name
to avoid the situation where section_name would require creating another
subdirectory for a pin (as, for example, when calling bpf_object__pin_programs
for programs in sections like "cgroup/connect6").
Signed-off-by: NStanislav Fomichev <sdf@google.com>
Signed-off-by: NAlexei Starovoitov <ast@kernel.org>

When bpf_program has only one instance, don't create a subdirectory with
per-instance pin files (<prog>/0). Instead, just create a single pin file
for that single instance. This simplifies object pinning by not creating
unnecessary subdirectories.

This can potentially break existing users that depend on the case
where '/0' is always created. However, I couldn't find any serious
usage of bpf_program__pin inside the kernel tree and I suppose there
should be none outside.
Signed-off-by: NStanislav Fomichev <sdf@google.com>
Signed-off-by: NAlexei Starovoitov <ast@kernel.org>

bpftool will use bpf_object__pin in the next commits to pin all programs
and maps from the file; in case of a partial failure, we need to get
back to the clean state (undo previous program/map pins).

As part of a cleanup, I've added and exported separate routines to
pin all maps (bpf_object__pin_maps) and progs (bpf_object__pin_programs)
of an object.
Signed-off-by: NStanislav Fomichev <sdf@google.com>
Signed-off-by: NAlexei Starovoitov <ast@kernel.org>

Makes it compatible with the logic that derives program type
from section name in libbpf_prog_type_by_name.
Signed-off-by: NStanislav Fomichev <sdf@google.com>
Signed-off-by: NAlexei Starovoitov <ast@kernel.org>

bpftool output is not user friendly when dumping a map with only a few
populated entries:

    $ bpftool map
    1: devmap  name tx_devmap  flags 0x0
            key 4B  value 4B  max_entries 64  memlock 4096B
    2: array  name tx_idxmap  flags 0x0
            key 4B  value 4B  max_entries 64  memlock 4096B

    $ bpftool map dump id 1
    key:
    00 00 00 00
    value:
    No such file or directory
    key:
    01 00 00 00
    value:
    No such file or directory
    key:
    02 00 00 00
    value:
    No such file or directory
    key: 03 00 00 00  value: 03 00 00 00

Handle ENOENT by keeping the line format sane and dumping
"<no entry>" for the value

    $ bpftool map dump id 1
    key: 00 00 00 00  value: <no entry>
    key: 01 00 00 00  value: <no entry>
    key: 02 00 00 00  value: <no entry>
    key: 03 00 00 00  value: 03 00 00 00
    ...
Signed-off-by: NDavid Ahern <dsahern@gmail.com>
Acked-by: NJakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: NDaniel Borkmann <daniel@iogearbox.net>

This patch provides a tcp_bpf based eBPF sample. The test

- ncat(1) as the TCP client program to connect() to a port
  with the intention of triggerring SYN retransmissions: we
  first install an iptables DROP rule to make sure ncat SYNs are
  resent (instead of aborting instantly after a TCP RST)

- has a bpf kernel module that sends a perf-event notification for
  each TCP retransmit, and also tracks the number of such notifications
  sent in the global_map

The test passes when the number of event notifications intercepted
in user-space matches the value in the global_map.
Signed-off-by: NSowmini Varadhan <sowmini.varadhan@oracle.com>
Signed-off-by: NDaniel Borkmann <daniel@iogearbox.net>

The limit for memory locked in the kernel by a process is usually set to
64 kbytes by default. This can be an issue when creating large BPF maps
and/or loading many programs. A workaround is to raise this limit for
the current process before trying to create a new BPF map. Changing the
hard limit requires the CAP_SYS_RESOURCE and can usually only be done by
root user (for non-root users, a call to setrlimit fails (and sets
errno) and the program simply goes on with its rlimit unchanged).

There is no API to get the current amount of memory locked for a user,
therefore we cannot raise the limit only when required. One solution,
used by bcc, is to try to create the map, and on getting a EPERM error,
raising the limit to infinity before giving another try. Another
approach, used in iproute2, is to raise the limit in all cases, before
trying to create the map.

Here we do the same as in iproute2: the rlimit is raised to infinity
before trying to load programs or to create maps with bpftool.
Signed-off-by: NQuentin Monnet <quentin.monnet@netronome.com>
Reviewed-by: NJakub Kicinski <jakub.kicinski@netronome.com>
Acked-by: NMartin KaFai Lau <kafai@fb.com>
Signed-off-by: NDaniel Borkmann <daniel@iogearbox.net>

libbpf is now able to load successfully test_l4lb_noinline.o and
samples/bpf/tracex3_kern.o.

For the test_l4lb_noinline, uncomment related tests from test_libbpf.c
and remove the associated "TODO".

For tracex3_kern.o, instead of loading a program from samples/bpf/ that
might not have been compiled at this stage, try loading a program from
BPF selftests. Since this test case is about loading a program compiled
without the "-target bpf" flag, change the Makefile to compile one
program accordingly (instead of passing the flag for compiling all
programs).

Regarding test_xdp_noinline.o: in its current shape the program fails to
load because it provides no version section, but the loader needs one.
The test was added to make sure that libbpf could load XDP programs even
if they do not provide a version number in a dedicated section. But
libbpf is already capable of doing that: in our case loading fails
because the loader does not know that this is an XDP program (it does
not need to, since it does not attach the program). So trying to load
test_xdp_noinline.o does not bring much here: just delete this subtest.

For the record, the error message obtained with tracex3_kern.o was
fixed by commit e3d91b0c ("tools/libbpf: handle issues with bpf ELF
objects containing .eh_frames")

I have not been abled to reproduce the "libbpf: incorrect bpf_call
opcode" error for test_l4lb_noinline.o, even with the version of libbpf
present at the time when test_libbpf.sh and test_libbpf_open.c were
created.

RFC -> v1:
- Compile test_xdp without the "-target bpf" flag, and try to load it
  instead of ../../samples/bpf/tracex3_kern.o.
- Delete test_xdp_noinline.o subtest.

Cc: Jesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: NQuentin Monnet <quentin.monnet@netronome.com>
Acked-by: NJakub Kicinski <jakub.kicinski@netronome.com>
Acked-by: NJesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: NDaniel Borkmann <daniel@iogearbox.net>

Starting with GCC 8, a lot of unlikely code was moved out of line to
"cold" subfunctions in .text.unlikely.

For example, the unlikely bits of:

  irq_do_set_affinity()

are moved out to the following subfunction:

  irq_do_set_affinity.cold.49()

Starting with GCC 9, the numbered suffix has been removed.  So in the
above example, the cold subfunction is instead:

  irq_do_set_affinity.cold()

Tweak the objtool subfunction detection logic so that it detects both
GCC 8 and GCC 9 naming schemes.
Reported-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: NJosh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Tested-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/015e9544b1f188d36a7f02fa31e9e95629aa5f50.1541040800.git.jpoimboe@redhat.com

Right now unprivileged tests are never executed as a BPF test run,
only loaded. Allow for running them as well so that we can check
the outcome and probe for regressions.
Signed-off-by: NDaniel Borkmann <daniel@iogearbox.net>
Acked-by: NAlexei Starovoitov <ast@kernel.org>
Signed-off-by: NAlexei Starovoitov <ast@kernel.org>

Add some more map related test cases to test_verifier kselftest
to improve test coverage. Summary: 1012 PASSED, 0 SKIPPED, 0 FAILED
Signed-off-by: NDaniel Borkmann <daniel@iogearbox.net>
Acked-by: NAlexei Starovoitov <ast@kernel.org>
Signed-off-by: NAlexei Starovoitov <ast@kernel.org>

We are using 'dscr_insn' as a label in inline asm to identify if a
SIGILL was generated by the mtspr instruction at that point. However,
with inline assembly, the compiler is still free to duplicate the asm
statement for optimization purposes, which results in the label being
defined twice with the error:
	/tmp/ccerQCql.s:874: Error: symbol `dscr_insn' is already defined

With different compiler versions, we may also see:
	/tmp/ccJzLDlN.o:(.toc+0x0): undefined reference to `dscr_insn'

Remove the use of the label in the inline assembly. Instead, just look
for the offending instruction in the signal handler.

Fixes: d2bf7932 ("selftests/powerpc: Add test to verify rfi flush across a system call")
Reported-by: NBreno Leitao <leitao@debian.org>
Signed-off-by: NNaveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Tested-by: NBreno Leitao <leitao@debian.org>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

Arnaldo Carvalho de Melo reported build error in libbpf when clang
version 3.8.1-24 (tags/RELEASE_381/final) is used:

libbpf.c:2201:36: error: comparison of constant -22 with expression of
type 'const enum bpf_attach_type' is always false
[-Werror,-Wtautological-constant-out-of-range-compare]
                if (section_names[i].attach_type == -EINVAL)
                    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ^  ~~~~~~~
1 error generated.

Fix the error by keeping "is_attachable" property of a program in a
separate struct field instead of trying to use attach_type itself.

Fixes: 956b620f ("libbpf: Introduce libbpf_attach_type_by_name")
Reported-by: NArnaldo Carvalho de Melo <acme@kernel.org>
Signed-off-by: NAndrey Ignatov <rdna@fb.com>
Tested-by: NArnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: NDaniel Borkmann <daniel@iogearbox.net>

ping binary on some distros doesn't support "ping -6" anymore.
Signed-off-by: NLi Zhijian <lizhijian@cn.fujitsu.com>
Acked-by: NSong Liu <songliubraving@fb.com>
Signed-off-by: NDaniel Borkmann <daniel@iogearbox.net>

In a previous patch, mlxsw was updated to configure a minimum bandwidth
allowance on MC TCs. Test that this indeed fixes the problem of UC
traffic overload pushing out all MC traffic.

Fixes: b5638d46 ("selftests: mlxsw: Add a test for UC behavior under MC flood")
Signed-off-by: NPetr Machata <petrm@mellanox.com>
Signed-off-by: NIdo Schimmel <idosch@mellanox.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Since the minimum shaper is now being enabled for MC TCs, it's
unreasonable to expect no UC traffic loss. Minimal min shaper value is
200Mbps, which is 20% of the 1Gbps that this test configures on egress.
To cover for glitches, tolerate up to 25% UC degradation under MC
overload.

Fixes: b5638d46 ("selftests: mlxsw: Add a test for UC behavior under MC flood")
Signed-off-by: NPetr Machata <petrm@mellanox.com>
Signed-off-by: NIdo Schimmel <idosch@mellanox.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

In the absence of a fallback, samples must provide a correct cpumode for
the 'ip'. Do that now there is no fallback.
Signed-off-by: NAdrian Hunter <adrian.hunter@intel.com>
Reviewed-by: NJiri Olsa <jolsa@kernel.org>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Leo Yan <leo.yan@linaro.org>
Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Cc: stable@vger.kernel.org # 4.19
Link: http://lkml.kernel.org/r/20181031091043.23465-6-adrian.hunter@intel.comSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>

In the absence of a fallback, callchains must encode also the callchain
context. Do that now there is no fallback.
Signed-off-by: NAdrian Hunter <adrian.hunter@intel.com>
Reviewed-by: NJiri Olsa <jolsa@kernel.org>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Leo Yan <leo.yan@linaro.org>
Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Cc: stable@vger.kernel.org # 4.19
Link: http://lkml.kernel.org/r/100ea2ec-ed14-b56d-d810-e0a6d2f4b069@intel.comSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>

When synthesizing FORK events, we are trying to create thread objects
for the already running tasks on the machine.

Normally, for a kernel FORK event, we want to clone the parent's maps
because that is what the kernel just did.

But when synthesizing, this should not be done.  If we do, we end up
with overlapping maps as we process the sythesized MMAP2 events that
get delivered shortly thereafter.

Use the FORK event misc flags in an internal way to signal this
situation, so we can elide the map clone when appropriate.
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
Cc: Don Zickus <dzickus@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Joe Mario <jmario@redhat.com>
Link: http://lkml.kernel.org/r/20181030.222404.2085088822877051075.davem@davemloft.net
[ Added comment about flag use in machine__process_fork_event(),
  use ternary op in thread__clone_map_groups() as suggested by Jiri ]
Signed-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>

If events are coming in at a rate such that the event processing thread
can barely keep up, our initial run of the event ring will almost never
terminate and this delays the starting of the display thread.

The screen basically stays black until the event thread can get out of
it's endless loop.

Therefore, start the display thread before we start processing the ring
buffer.

This also make sure that we always have the user requested real time
setting engaged when processing the ring.
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
Tested-by: NArnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: http://lkml.kernel.org/r/20181030.223003.2242527041807905962.davem@davemloft.netSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>

To pick the changes from:

  9163a0fc ("net: bridge: add support for per-port vlan stats")

And silence this build warning:

  Warning: Kernel ABI header at 'tools/include/uapi/linux/if_link.h' differs from latest version at 'include/uapi/linux/if_link.h'

Cc: Alexei Starovoitov <ast@kernel.org>
Cc: David S. Miller <davem@davemloft.net>
Cc: Eric Leblond <eric@regit.org>
Cc: Nikolay Aleksandrov <nikolay@cumulusnetworks.com>
Link: https://lkml.kernel.org/n/tip-7p53ghippywz7fqkwo3nkzet@git.kernel.orgSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>

Picking the changes from:

  89d35528 ("netlink: Add new socket option to enable strict checking on dumps")

To silence this build warning:

  Warning: Kernel ABI header at 'tools/include/uapi/linux/netlink.h' differs from latest version at 'include/uapi/linux/netlink.h'

Cc: Alexei Starovoitov <ast@kernel.org>
Cc: David Ahern <dsahern@gmail.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Eric Leblond <eric@regit.org>
Link: https://lkml.kernel.org/n/tip-1xymkfjpmhxfzrs46t8z8mjw@git.kernel.orgSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>

For powerpc, s390, x86 and the main uapi linux/kvm.h header, none of
them entail changes in tooling.

Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: https://lkml.kernel.org/n/tip-avn7iy8f4tcm2y40sbsdk31m@git.kernel.orgSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>

To pick up the changes from:

  20916d46 ("mm/hugetlb: add mmap() encodings for 32MB and 512MB page sizes")

That do not entail changes in in tools, this just shows that we have to
consider bits [26:31] of flags to beautify that in tools like 'perf
trace'

This silences this perf build warning:

  Warning: Kernel ABI header at 'tools/include/uapi/linux/mman.h' differs from latest version at 'include/uapi/linux/mman.h'
  diff -u tools/include/uapi/linux/mman.h include/uapi/linux/mman.h

Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: https://lkml.kernel.org/n/tip-3rvc39lon93kgt5pl31d8g4x@git.kernel.orgSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>

Instead of requiring us to go on and edit sources to add new flag.

  # perf trace -e *mmap sleep 0.1
     0.025 ( 0.005 ms): sleep/29876 mmap(len: 163746, prot: READ, flags: PRIVATE, fd: 3) = 0x7faa68ad1000
     0.059 ( 0.004 ms): sleep/29876 mmap(len: 8192, prot: READ|WRITE, flags: PRIVATE|ANONYMOUS) = 0x7faa68acf000
     0.069 ( 0.006 ms): sleep/29876 mmap(len: 3889792, prot: EXEC|READ, flags: PRIVATE|DENYWRITE, fd: 3) = 0x7faa6851f000
     0.086 ( 0.009 ms): sleep/29876 mmap(addr: 0x7faa688cb000, len: 24576, prot: READ|WRITE, flags: PRIVATE|FIXED|DENYWRITE, fd: 3, off: 1753088) = 0x7faa688cb000
     0.101 ( 0.005 ms): sleep/29876 mmap(addr: 0x7faa688d1000, len: 14976, prot: READ|WRITE, flags: PRIVATE|FIXED|ANONYMOUS) = 0x7faa688d1000
     0.348 ( 0.005 ms): sleep/29876 mmap(len: 111950656, prot: READ, flags: PRIVATE, fd: 3) = 0x7faa61a5b000
  #

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Wang Nan <wangnan0@huawei.com>
Link: https://lkml.kernel.org/n/tip-ggmoy6vxoygh5yim890ht0kf@git.kernel.orgSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>

Now when we run 'make -C tools/perf O=/tmp/build/perf' we end up with:

  $ cat /tmp/build/perf/trace/beauty/generated/mmap_flags_array.c
  static const char *mmap_flags[] = {
	[ilog2(0x40) + 1] = "32BIT",
	[ilog2(0x01) + 1] = "SHARED",
	[ilog2(0x02) + 1] = "PRIVATE",
	[ilog2(0x10) + 1] = "FIXED",
	[ilog2(0x20) + 1] = "ANONYMOUS",
	[ilog2(0x100000) + 1] = "FIXED_NOREPLACE",
	[ilog2(0x0100) + 1] = "GROWSDOWN",
	[ilog2(0x0800) + 1] = "DENYWRITE",
	[ilog2(0x1000) + 1] = "EXECUTABLE",
	[ilog2(0x2000) + 1] = "LOCKED",
	[ilog2(0x4000) + 1] = "NORESERVE",
	[ilog2(0x8000) + 1] = "POPULATE",
	[ilog2(0x10000) + 1] = "NONBLOCK",
	[ilog2(0x20000) + 1] = "STACK",
	[ilog2(0x40000) + 1] = "HUGETLB",
	[ilog2(0x80000) + 1] = "SYNC",
  };
  $

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Wang Nan <wangnan0@huawei.com>
Link: https://lkml.kernel.org/n/tip-t3fn7u3tjsupio6e6vkufx9m@git.kernel.orgSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>

It'll use tools/{arch}/*,include copies of mman.h to generate a table to
be used by tools, initially by the 'mmap' beautifiers in 'perf trace',
but that could also be used to translate from a string constant to the
integer value to be used in a eBPF or tracefs tracepoint filter.

Tested for all archs using:

$ for arch in `ls tools/arch/` ; \
	do echo $arch ; tools/perf/trace/beauty/mmap_flags.sh $arch ; \
   done | less

Example for alpha, an oddball, doesn't include any header, defines all
its stuff:

  $ tools/perf/trace/beauty/mmap_flags.sh alpha
  static const char *mmap_flags[] = {
	[ilog2(0x10) + 1] = "ANONYMOUS",
	[ilog2(0x02000) + 1] = "DENYWRITE",
	[ilog2(0x04000) + 1] = "EXECUTABLE",
	[ilog2(0x100) + 1] = "FIXED",
	[ilog2(0x01000) + 1] = "GROWSDOWN",
	[ilog2(0x100000) + 1] = "HUGETLB",
	[ilog2(0x08000) + 1] = "LOCKED",
	[ilog2(0x40000) + 1] = "NONBLOCK",
	[ilog2(0x10000) + 1] = "NORESERVE",
	[ilog2(0x20000) + 1] = "POPULATE",
	[ilog2(0x02) + 1] = "PRIVATE",
	[ilog2(0x01) + 1] = "SHARED",
	[ilog2(0x80000) + 1] = "STACK",
  };
  $

Common case, my workstation, defines one entry (MAP_32BIT), then
includes mman.h, which gets it to include mman-common.h too:

  $ tools/perf/trace/beauty/mmap_flags.sh
  static const char *mmap_flags[] = {
	[ilog2(0x40) + 1] = "32BIT",
	[ilog2(0x01) + 1] = "SHARED",
	[ilog2(0x02) + 1] = "PRIVATE",
	[ilog2(0x10) + 1] = "FIXED",
	[ilog2(0x20) + 1] = "ANONYMOUS",
	[ilog2(0x100000) + 1] = "FIXED_NOREPLACE",
	[ilog2(0x0100) + 1] = "GROWSDOWN",
	[ilog2(0x0800) + 1] = "DENYWRITE",
	[ilog2(0x1000) + 1] = "EXECUTABLE",
	[ilog2(0x2000) + 1] = "LOCKED",
	[ilog2(0x4000) + 1] = "NORESERVE",
	[ilog2(0x8000) + 1] = "POPULATE",
	[ilog2(0x10000) + 1] = "NONBLOCK",
	[ilog2(0x20000) + 1] = "STACK",
	[ilog2(0x40000) + 1] = "HUGETLB",
	[ilog2(0x80000) + 1] = "SYNC",
  };
  $ uname -m
  x86_64
  $

Sparc, that defines a bunch then includes just mman-common.h:

  $ tools/perf/trace/beauty/mmap_flags.sh sparc
  static const char *mmap_flags[] = {
	[ilog2(0x0800) + 1] = "DENYWRITE",
	[ilog2(0x1000) + 1] = "EXECUTABLE",
	[ilog2(0x0200) + 1] = "GROWSDOWN",
	[ilog2(0x40000) + 1] = "HUGETLB",
	[ilog2(0x100) + 1] = "LOCKED",
	[ilog2(0x10000) + 1] = "NONBLOCK",
	[ilog2(0x40) + 1] = "NORESERVE",
	[ilog2(0x8000) + 1] = "POPULATE",
	[ilog2(0x20000) + 1] = "STACK",
	[ilog2(0x01) + 1] = "SHARED",
	[ilog2(0x02) + 1] = "PRIVATE",
	[ilog2(0x10) + 1] = "FIXED",
	[ilog2(0x20) + 1] = "ANONYMOUS",
	[ilog2(0x100000) + 1] = "FIXED_NOREPLACE",
  };
  [acme@jouet perf]$

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Wang Nan <wangnan0@huawei.com>
Link: https://lkml.kernel.org/n/tip-xydeh491z8fkgglcmqnl5thj@git.kernel.orgSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>

To silence this perf build warning:

  Warning: Kernel ABI header at 'tools/include/uapi/sound/asound.h' differs from latest version at 'include/uapi/sound/asound.h'
  diff -u tools/include/uapi/sound/asound.h include/uapi/sound/asound.h

Due to this cset:

  a9840151 ("ALSA: timer: fix wrong comment to refer to 'SNDRV_TIMER_PSFLG_*'")

Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Cc: Takashi Iwai <tiwai@suse.de>
Link: https://lkml.kernel.org/n/tip-76gsvs0w2g0x723ivqa2xua3@git.kernel.orgSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>

To get the changes in:

  82b355d1 ("y2038: Remove newstat family from default syscall set")

Which will make the syscall table used by 'perf trace' for arm64 to be
updated from the changes in that patch.

This silences these perf build warnings:

  Warning: Kernel ABI header at 'tools/arch/arm64/include/uapi/asm/unistd.h' differs from latest version at 'arch/arm64/include/uapi/asm/unistd.h'
  diff -u tools/arch/arm64/include/uapi/asm/unistd.h arch/arm64/include/uapi/asm/unistd.h
  Warning: Kernel ABI header at 'tools/include/uapi/asm-generic/unistd.h' differs from latest version at 'include/uapi/asm-generic/unistd.h'
  diff -u tools/include/uapi/asm-generic/unistd.h include/uapi/asm-generic/unistd.h

Cc: Kim Phillips <kim.phillips@arm.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: https://lkml.kernel.org/n/tip-3euy7c4yy5mvnp5bm16t9vqg@git.kernel.orgSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>

To silence this perf build warning:

  Warning: Kernel ABI header at 'tools/include/uapi/linux/fs.h' differs from latest version at 'include/uapi/linux/fs.h'
  diff -u tools/include/uapi/linux/fs.h include/uapi/linux/fs.h

Due to just two comments added by:

  Fixes: 578bdaab ("crypto: speck - remove Speck")

So nothing that entails changes in tools/, that so far uses fs.h to
generate the mount and umount syscalls 'flags' argument integer->string
tables with:

  $ tools/perf/trace/beauty/mount_flags.sh
  static const char *mount_flags[] = {
	[4096 ? (ilog2(4096) + 1) : 0] = "BIND",
<SNIP>
	[30 + 1] = "ACTIVE",
	[31 + 1] = "NOUSER",
  };
  $
  # trace -e mount,umount mount --bind /proc /mnt
     1.228 ( 2.581 ms): mount/1068 mount(dev_name: /mnt, dir_name: 0x55f011c354a0, type: 0x55f011c38170, flags: BIND) = 0
  # trace -e mount,umount umount /proc /mnt
  umount: /proc: target is busy.
     1.587 ( 0.010 ms): umount/1070 umount2(name: /proc) = -1 EBUSY Device or resource busy
     1.799 (12.660 ms): umount/1070 umount2(name: /mnt) = 0
  #

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Wang Nan <wangnan0@huawei.com>
Cc: Jason A. Donenfeld <Jason@zx2c4.com>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Link: https://lkml.kernel.org/n/tip-c00bqzclscgah26z2g5zxm73@git.kernel.orgSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>

When processing using 'perf report -g caller', which is the default, we
ended up reverting the callchain entries received from the kernel, but
simply reverting throws away the information that tells that from a
point onwards the addresses are for userspace, kernel, guest kernel,
guest user, hypervisor.

The idea is that if we are walking backwards, for each cluster of
non-cpumode entries we have to first scan backwards for the next one and
use that for the cluster.

This seems silly and more expensive than it needs to be but it is enough
for a initial fix.

The code here is really complicated because it is intimately intertwined
with the lbr and branch handling, as well as this callchain order,
further fixes will be needed to properly take into account the cpumode
in those cases.

Another problem with ORDER_CALLER is that the NULL "0" IP that is at the
end of most callchains shows up at the top of the histogram because
every callchain contains it and with ORDER_CALLER it is the first entry.
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
Tested-by: NArnaldo Carvalho de Melo <acme@redhat.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Souvik Banerjee <souvik1997@gmail.com>
Cc: Wang Nan <wangnan0@huawei.com>
Cc: stable@vger.kernel.org # 4.19
Link: https://lkml.kernel.org/n/tip-2wt3ayp6j2y2f2xowixa8y6y@git.kernel.orgSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>

Since commit edeb0c90 ("perf tools: Stop fallbacking to kallsyms for
vdso symbols lookup"), the kernel address cannot be properly parsed to
kernel symbol with command 'perf script -k vmlinux'.  The reason is
CoreSight samples is always to set CPU mode as PERF_RECORD_MISC_USER,
thus it fails to find corresponding map/dso in below flows:

  process_sample_event()
    `-> machine__resolve()
	  `-> thread__find_map(thread, sample->cpumode, sample->ip, al);

In this flow it needs to pass argument 'sample->cpumode' to tell what's
the CPU mode, before it always passed PERF_RECORD_MISC_USER but without
any failure until the commit edeb0c90 ("perf tools: Stop fallbacking
to kallsyms for vdso symbols lookup") has been merged.  The reason is
even with the wrong CPU mode the function thread__find_map() firstly
fails to find map but it will rollback to find kernel map for vdso
symbols lookup.  In the latest code it has removed the fallback code,
thus if CPU mode is PERF_RECORD_MISC_USER then it cannot find map
anymore with kernel address.

This patch is to correct samples CPU mode setting, it creates a new
helper function cs_etm__cpu_mode() to tell what's the CPU mode based on
the address with the info from machine structure; this patch has a bit
extension to check not only kernel and user mode, but also check for
host/guest and hypervisor mode.  Finally this patch uses the function in
instruction and branch samples and also apply in cs_etm__mem_access()
for a minor polishing.
Signed-off-by: NLeo Yan <leo.yan@linaro.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: David Miller <davem@davemloft.net>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: coresight@lists.linaro.org
Cc: linux-arm-kernel@lists.infradead.org
Cc: stable@kernel.org # v4.19
Link: http://lkml.kernel.org/r/1540883908-17018-1-git-send-email-leo.yan@linaro.orgSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>

libdwfl parses an ELF file itself and creates mappings for the
individual sections. perf on the other hand sees raw mmap events which
represent individual sections. When we encounter an address pointing
into a mapping with pgoff != 0, we must take that into account and
report the file at the non-offset base address.

This fixes unwinding with libdwfl in some cases. E.g. for a file like:

```

using namespace std;

mutex g_mutex;

double worker()
{
    lock_guard<mutex> guard(g_mutex);
    uniform_real_distribution<double> uniform(-1E5, 1E5);
    default_random_engine engine;
    double s = 0;
    for (int i = 0; i < 1000; ++i) {
        s += norm(complex<double>(uniform(engine), uniform(engine)));
    }
    cout << s << endl;
    return s;
}

int main()
{
    vector<std::future<double>> results;
    for (int i = 0; i < 10000; ++i) {
        results.push_back(async(launch::async, worker));
    }
    return 0;
}
```

Compile it with `g++ -g -O2 -lpthread cpp-locking.cpp  -o cpp-locking`,
then record it with `perf record --call-graph dwarf -e
sched:sched_switch`.

When you analyze it with `perf script` and libunwind, you should see:

```
cpp-locking 20038 [005] 54830.236589: sched:sched_switch: prev_comm=cpp-locking prev_pid=20038 prev_prio=120 prev_state=T ==> next_comm=swapper/5 next_pid=0 next_prio=120
        ffffffffb166fec5 __sched_text_start+0x545 (/lib/modules/4.14.78-1-lts/build/vmlinux)
        ffffffffb166fec5 __sched_text_start+0x545 (/lib/modules/4.14.78-1-lts/build/vmlinux)
        ffffffffb1670208 schedule+0x28 (/lib/modules/4.14.78-1-lts/build/vmlinux)
        ffffffffb16737cc rwsem_down_read_failed+0xec (/lib/modules/4.14.78-1-lts/build/vmlinux)
        ffffffffb1665e04 call_rwsem_down_read_failed+0x14 (/lib/modules/4.14.78-1-lts/build/vmlinux)
        ffffffffb1672a03 down_read+0x13 (/lib/modules/4.14.78-1-lts/build/vmlinux)
        ffffffffb106bd85 __do_page_fault+0x445 (/lib/modules/4.14.78-1-lts/build/vmlinux)
        ffffffffb18015f5 page_fault+0x45 (/lib/modules/4.14.78-1-lts/build/vmlinux)
            7f38e4252591 new_heap+0x101 (/usr/lib/libc-2.28.so)
            7f38e4252d0b arena_get2.part.4+0x2fb (/usr/lib/libc-2.28.so)
            7f38e4255b1c tcache_init.part.6+0xec (/usr/lib/libc-2.28.so)
            7f38e42569e5 __GI___libc_malloc+0x115 (inlined)
            7f38e4241790 __GI__IO_file_doallocate+0x90 (inlined)
            7f38e424fbbf __GI__IO_doallocbuf+0x4f (inlined)
            7f38e424ee47 __GI__IO_file_overflow+0x197 (inlined)
            7f38e424df36 _IO_new_file_xsputn+0x116 (inlined)
            7f38e4242bfb __GI__IO_fwrite+0xdb (inlined)
            7f38e463fa6d std::basic_streambuf<char, std::char_traits<char> >::sputn(char const*, long)+0x1cd (inlined)
            7f38e463fa6d std::ostreambuf_iterator<char, std::char_traits<char> >::_M_put(char const*, long)+0x1cd (inlined)
            7f38e463fa6d std::ostreambuf_iterator<char, std::char_traits<char> > std::__write<char>(std::ostreambuf_iterator<char, std::char_traits<char> >, char const*, int)+0x1cd (inlined)
            7f38e463fa6d std::ostreambuf_iterator<char, std::char_traits<char> > std::num_put<char, std::ostreambuf_iterator<char, std::char_traits<char> > >::_M_insert_float<double>(std::ostreambuf_iterator<c>
            7f38e464bd70 std::num_put<char, std::ostreambuf_iterator<char, std::char_traits<char> > >::put(std::ostreambuf_iterator<char, std::char_traits<char> >, std::ios_base&, char, double) const+0x90 (inl>
            7f38e464bd70 std::ostream& std::ostream::_M_insert<double>(double)+0x90 (/usr/lib/libstdc++.so.6.0.25)
            563b9cb502f7 std::ostream::operator<<(double)+0xb7 (inlined)
            563b9cb502f7 worker()+0xb7 (/ssd/milian/projects/kdab/rnd/hotspot/build/tests/test-clients/cpp-locking/cpp-locking)
            563b9cb506fb double std::__invoke_impl<double, double (*)()>(std::__invoke_other, double (*&&)())+0x2b (inlined)
            563b9cb506fb std::__invoke_result<double (*)()>::type std::__invoke<double (*)()>(double (*&&)())+0x2b (inlined)
            563b9cb506fb decltype (__invoke((_S_declval<0ul>)())) std::thread::_Invoker<std::tuple<double (*)()> >::_M_invoke<0ul>(std::_Index_tuple<0ul>)+0x2b (inlined)
            563b9cb506fb std::thread::_Invoker<std::tuple<double (*)()> >::operator()()+0x2b (inlined)
            563b9cb506fb std::__future_base::_Task_setter<std::unique_ptr<std::__future_base::_Result<double>, std::__future_base::_Result_base::_Deleter>, std::thread::_Invoker<std::tuple<double (*)()> >, dou>
            563b9cb506fb std::_Function_handler<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter> (), std::__future_base::_Task_setter<std::unique_ptr<std::__future_>
            563b9cb507e8 std::function<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter> ()>::operator()() const+0x28 (inlined)
            563b9cb507e8 std::__future_base::_State_baseV2::_M_do_set(std::function<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter> ()>*, bool*)+0x28 (/ssd/milian/>
            7f38e46d24fe __pthread_once_slow+0xbe (/usr/lib/libpthread-2.28.so)
            563b9cb51149 __gthread_once+0xe9 (inlined)
            563b9cb51149 void std::call_once<void (std::__future_base::_State_baseV2::*)(std::function<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter> ()>*, bool*)>
            563b9cb51149 std::__future_base::_State_baseV2::_M_set_result(std::function<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter> ()>, bool)+0xe9 (inlined)
            563b9cb51149 std::__future_base::_Async_state_impl<std::thread::_Invoker<std::tuple<double (*)()> >, double>::_Async_state_impl(std::thread::_Invoker<std::tuple<double (*)()> >&&)::{lambda()#1}::op>
            563b9cb51149 void std::__invoke_impl<void, std::__future_base::_Async_state_impl<std::thread::_Invoker<std::tuple<double (*)()> >, double>::_Async_state_impl(std::thread::_Invoker<std::tuple<double>
            563b9cb51149 std::__invoke_result<std::__future_base::_Async_state_impl<std::thread::_Invoker<std::tuple<double (*)()> >, double>::_Async_state_impl(std::thread::_Invoker<std::tuple<double (*)()> >>
            563b9cb51149 decltype (__invoke((_S_declval<0ul>)())) std::thread::_Invoker<std::tuple<std::__future_base::_Async_state_impl<std::thread::_Invoker<std::tuple<double (*)()> >, double>::_Async_state_>
            563b9cb51149 std::thread::_Invoker<std::tuple<std::__future_base::_Async_state_impl<std::thread::_Invoker<std::tuple<double (*)()> >, double>::_Async_state_impl(std::thread::_Invoker<std::tuple<dou>
            563b9cb51149 std::thread::_State_impl<std::thread::_Invoker<std::tuple<std::__future_base::_Async_state_impl<std::thread::_Invoker<std::tuple<double (*)()> >, double>::_Async_state_impl(std::thread>
            7f38e45f0062 execute_native_thread_routine+0x12 (/usr/lib/libstdc++.so.6.0.25)
            7f38e46caa9c start_thread+0xfc (/usr/lib/libpthread-2.28.so)
            7f38e42ccb22 __GI___clone+0x42 (inlined)
```

Before this patch, using libdwfl, you would see:

```
cpp-locking 20038 [005] 54830.236589: sched:sched_switch: prev_comm=cpp-locking prev_pid=20038 prev_prio=120 prev_state=T ==> next_comm=swapper/5 next_pid=0 next_prio=120
        ffffffffb166fec5 __sched_text_start+0x545 (/lib/modules/4.14.78-1-lts/build/vmlinux)
        ffffffffb166fec5 __sched_text_start+0x545 (/lib/modules/4.14.78-1-lts/build/vmlinux)
        ffffffffb1670208 schedule+0x28 (/lib/modules/4.14.78-1-lts/build/vmlinux)
        ffffffffb16737cc rwsem_down_read_failed+0xec (/lib/modules/4.14.78-1-lts/build/vmlinux)
        ffffffffb1665e04 call_rwsem_down_read_failed+0x14 (/lib/modules/4.14.78-1-lts/build/vmlinux)
        ffffffffb1672a03 down_read+0x13 (/lib/modules/4.14.78-1-lts/build/vmlinux)
        ffffffffb106bd85 __do_page_fault+0x445 (/lib/modules/4.14.78-1-lts/build/vmlinux)
        ffffffffb18015f5 page_fault+0x45 (/lib/modules/4.14.78-1-lts/build/vmlinux)
            7f38e4252591 new_heap+0x101 (/usr/lib/libc-2.28.so)
        a041161e77950c5c [unknown] ([unknown])
```

With this patch applied, we get a bit further in unwinding:

```
cpp-locking 20038 [005] 54830.236589: sched:sched_switch: prev_comm=cpp-locking prev_pid=20038 prev_prio=120 prev_state=T ==> next_comm=swapper/5 next_pid=0 next_prio=120
        ffffffffb166fec5 __sched_text_start+0x545 (/lib/modules/4.14.78-1-lts/build/vmlinux)
        ffffffffb166fec5 __sched_text_start+0x545 (/lib/modules/4.14.78-1-lts/build/vmlinux)
        ffffffffb1670208 schedule+0x28 (/lib/modules/4.14.78-1-lts/build/vmlinux)
        ffffffffb16737cc rwsem_down_read_failed+0xec (/lib/modules/4.14.78-1-lts/build/vmlinux)
        ffffffffb1665e04 call_rwsem_down_read_failed+0x14 (/lib/modules/4.14.78-1-lts/build/vmlinux)
        ffffffffb1672a03 down_read+0x13 (/lib/modules/4.14.78-1-lts/build/vmlinux)
        ffffffffb106bd85 __do_page_fault+0x445 (/lib/modules/4.14.78-1-lts/build/vmlinux)
        ffffffffb18015f5 page_fault+0x45 (/lib/modules/4.14.78-1-lts/build/vmlinux)
            7f38e4252591 new_heap+0x101 (/usr/lib/libc-2.28.so)
            7f38e4252d0b arena_get2.part.4+0x2fb (/usr/lib/libc-2.28.so)
            7f38e4255b1c tcache_init.part.6+0xec (/usr/lib/libc-2.28.so)
            7f38e42569e5 __GI___libc_malloc+0x115 (inlined)
            7f38e4241790 __GI__IO_file_doallocate+0x90 (inlined)
            7f38e424fbbf __GI__IO_doallocbuf+0x4f (inlined)
            7f38e424ee47 __GI__IO_file_overflow+0x197 (inlined)
            7f38e424df36 _IO_new_file_xsputn+0x116 (inlined)
            7f38e4242bfb __GI__IO_fwrite+0xdb (inlined)
            7f38e463fa6d std::basic_streambuf<char, std::char_traits<char> >::sputn(char const*, long)+0x1cd (inlined)
            7f38e463fa6d std::ostreambuf_iterator<char, std::char_traits<char> >::_M_put(char const*, long)+0x1cd (inlined)
            7f38e463fa6d std::ostreambuf_iterator<char, std::char_traits<char> > std::__write<char>(std::ostreambuf_iterator<char, std::char_traits<char> >, char const*, int)+0x1cd (inlined)
            7f38e463fa6d std::ostreambuf_iterator<char, std::char_traits<char> > std::num_put<char, std::ostreambuf_iterator<char, std::char_traits<char> > >::_M_insert_float<double>(std::ostreambuf_iterator<c>
            7f38e464bd70 std::num_put<char, std::ostreambuf_iterator<char, std::char_traits<char> > >::put(std::ostreambuf_iterator<char, std::char_traits<char> >, std::ios_base&, char, double) const+0x90 (inl>
            7f38e464bd70 std::ostream& std::ostream::_M_insert<double>(double)+0x90 (/usr/lib/libstdc++.so.6.0.25)
            563b9cb502f7 std::ostream::operator<<(double)+0xb7 (inlined)
            563b9cb502f7 worker()+0xb7 (/ssd/milian/projects/kdab/rnd/hotspot/build/tests/test-clients/cpp-locking/cpp-locking)
        6eab825c1ee3e4ff [unknown] ([unknown])
```

Note that the backtrace is still stopping too early, when compared to
the nice results obtained via libunwind. It's unclear so far what the
reason for that is.

Committer note:

Further comment by Milian on the thread started on the Link: tag below:

 ---
The remaining issue is due to a bug in elfutils:

https://sourceware.org/ml/elfutils-devel/2018-q4/msg00089.html

With both patches applied, libunwind and elfutils produce the same output for
the above scenario.
 ---
Signed-off-by: NMilian Wolff <milian.wolff@kdab.com>
Acked-by: NJiri Olsa <jolsa@kernel.org>
Link: http://lkml.kernel.org/r/20181029141644.3907-1-milian.wolff@kdab.comSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>

Enabling --overwrite mode allows us to to use just the most recent
records, which helps in high core count machines such as Knights
Landing/Mill, but right now is being disabled by default as the pausing
used in this technique is leading to loss of metadata events such as
PERF_RECORD_MMAP which makes 'perf top' unable to resolve samples,
leading to lots of unknown samples appearing on the UI.

Enabling this may be useful if you are in such machines and profiling a
workload that doesn't creates short lived threads and/or doesn't uses
many executable mmap operations.

Work is being planed to solve this situation, till then, this will
remain disabled by default.
Reported-by: NDavid Miller <davem@davemloft.net>
Acked-by: NKan Liang <kan.liang@intel.com>
Link: https://lkml.kernel.org/r/4f84468f-37d9-cf1b-12c1-514ef74b6a48@linux.intel.com
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Wang Nan <wangnan0@huawei.com>
Fixes: ebebbf08 ("perf top: Switch default mode to overwrite mode")
Link: https://lkml.kernel.org/n/tip-ehvf77vi1si9409r7p4wx788@git.kernel.orgSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>

Use TEST_GEN_PROGS and don't redefine all, this makes the out-of-tree
build work. We need to move the extra dependencies below the include
of lib.mk, because it adds the $(OUTPUT) prefix if it's defined.

We can also drop the clean rule, lib.mk does it for us.
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

For the out-of-tree build to work we need to tell switch_endian_test
to look for check-reversed.S in $(OUTPUT).
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>