$ cat /tmp/build/perf/trace/beauty/generated/x86_arch_prctl_code_array.c
  #define x86_arch_prctl_codes_1_offset 0x1001
  static const char *x86_arch_prctl_codes_1[] = {
	[0x1001 - 0x1001]= "SET_GS",
	[0x1002 - 0x1001]= "SET_FS",
	[0x1003 - 0x1001]= "GET_FS",
	[0x1004 - 0x1001]= "GET_GS",
	[0x1011 - 0x1001]= "GET_CPUID",
	[0x1012 - 0x1001]= "SET_CPUID",
  };

  #define x86_arch_prctl_codes_2_offset 0x2001
  static const char *x86_arch_prctl_codes_2[] = {
	[0x2001 - 0x2001]= "MAP_VDSO_X32",
	[0x2002 - 0x2001]= "MAP_VDSO_32",
	[0x2003 - 0x2001]= "MAP_VDSO_64",
  };
  $

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Luis Cláudio Gonçalves <lclaudio@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Wang Nan <wangnan0@huawei.com>
Link: https://lkml.kernel.org/n/tip-3r9blij6n8wdlsyd5dujx86r@git.kernel.orgSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

  $ tools/perf/trace/beauty/x86_arch_prctl.sh
  #define x86_arch_prctl_codes_1_offset 0x1001
  static const char *x86_arch_prctl_codes_1[] = {
	[0x1001 - 0x1001]= "SET_GS",
	[0x1002 - 0x1001]= "SET_FS",
	[0x1003 - 0x1001]= "GET_FS",
	[0x1004 - 0x1001]= "GET_GS",
	[0x1011 - 0x1001]= "GET_CPUID",
	[0x1012 - 0x1001]= "SET_CPUID",
  };

  #define x86_arch_prctl_codes_2_offset 0x2001
  static const char *x86_arch_prctl_codes_2[] = {
	[0x2001 - 0x2001]= "MAP_VDSO_X32",
	[0x2002 - 0x2001]= "MAP_VDSO_32",
	[0x2003 - 0x2001]= "MAP_VDSO_64",
  };
  $

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Luis Cláudio Gonçalves <lclaudio@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Wang Nan <wangnan0@huawei.com>
Link: https://lkml.kernel.org/n/tip-w0fux1psivphhx6rve8kn3vq@git.kernel.orgSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

We need it to generate the tables for the 'code' arch_prctl's syscall
argument.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Luis Cláudio Gonçalves <lclaudio@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Wang Nan <wangnan0@huawei.com>
Link: https://lkml.kernel.org/n/tip-vu890pi18fpd4eyz61cazckj@git.kernel.orgSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

Matching strace's output format. The 'format' file for the syscall
tracepoints have an indication if the arg is a pointer, with some
exceptions like 'mmap' that has its first arg as an 'unsigned long', so
use a heuristic using the argument name, i.e. if it contains the 'addr'
substring, format it with the pointer formatter.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Luis Cláudio Gonçalves <lclaudio@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Wang Nan <wangnan0@huawei.com>
Link: https://lkml.kernel.org/n/tip-ddghemr8qrm6i0sb8awznbze@git.kernel.orgSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

To match strace, now both emit the same line for calls like:

 access("/etc/ld.so.preload", R_OK)      = -1 ENOENT (No such file or directory)

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Luis Cláudio Gonçalves <lclaudio@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Wang Nan <wangnan0@huawei.com>
Link: https://lkml.kernel.org/n/tip-krxl6klsqc9qyktoaxyih942@git.kernel.orgSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

This will all come from userspace, but to test the changes to make 'perf
trace' output similar to strace's, do this one more now manually.

To update the precompiled augmented_raw_syscalls.o binary I just run:

  # perf record -e ~acme/git/perf/tools/perf/examples/bpf/augmented_raw_syscalls.c sleep 1
  LLVM: dumping /home/acme/git/perf/tools/perf/examples/bpf/augmented_raw_syscalls.o
  [ perf record: Woken up 1 times to write data ]
  [ perf record: Captured and wrote 0.022 MB perf.data ]
  #

Because to have augmented_raw_syscalls to be always used and a fast
startup and remove the need to have the llvm toolchain installed, I'm
using:

  # perf config | grep add_events
  trace.add_events=/home/acme/git/perf/tools/perf/examples/bpf/augmented_raw_syscalls.o
  #

So when doing changes to augmented_raw_syscals.c one needs to rebuild
the .o file.

This will be done automagically later, i.e. have a 'make' behaviour of
recompiling when the .c gets changed.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Luis Cláudio Gonçalves <lclaudio@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Wang Nan <wangnan0@huawei.com>
Link: https://lkml.kernel.org/n/tip-lw3i2atyq8549fpqwmszn3qp@git.kernel.orgSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

To use strace's style, helping in comparing the output of 'perf trace'
with the one from 'strace', to help in upcoming regression tests.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Luis Cláudio Gonçalves <lclaudio@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Wang Nan <wangnan0@huawei.com>
Link: https://lkml.kernel.org/n/tip-mw6peotz4n84rga0fk78buff@git.kernel.orgSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

And there are more flags, to match strace's output.

 openat(AT_FDCWD, "/etc/ld.so.cache", O_RDONLY|O_CLOEXEC) = 3

Also to help with regression tests.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Luis Cláudio Gonçalves <lclaudio@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Wang Nan <wangnan0@huawei.com>
Link: https://lkml.kernel.org/n/tip-ofovpmvdli3bwch30936xn7t@git.kernel.orgSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

So far we've been suppressing common stuff such as "MAP_" in the mmap
flags, showing "SHARED" instead of "MAP_SHARED", allow for those
prefixes (and a few suffixes) to be shown:

  # trace -e *map,open*,*seek sleep 1
  openat("/etc/ld.so.cache", CLOEXEC) = 3
  mmap(0, 109093, READ, PRIVATE, 3, 0) = 0x7ff61c695000
  openat("/lib64/libc.so.6", CLOEXEC) = 3
  lseek(3, 792, SET) = 792
  mmap(0, 8192, READ|WRITE, PRIVATE|ANONYMOUS) = 0x7ff61c693000
  lseek(3, 792, SET) = 792
  lseek(3, 864, SET) = 864
  mmap(0, 1857568, READ, PRIVATE|DENYWRITE, 3, 0) = 0x7ff61c4cd000
  mmap(0x7ff61c4ef000, 1363968, EXEC|READ, PRIVATE|FIXED|DENYWRITE, 3, 139264) = 0x7ff61c4ef000
  mmap(0x7ff61c63c000, 311296, READ, PRIVATE|FIXED|DENYWRITE, 3, 1503232) = 0x7ff61c63c000
  mmap(0x7ff61c689000, 24576, READ|WRITE, PRIVATE|FIXED|DENYWRITE, 3, 1814528) = 0x7ff61c689000
  mmap(0x7ff61c68f000, 14368, READ|WRITE, PRIVATE|FIXED|ANONYMOUS) = 0x7ff61c68f000
  munmap(0x7ff61c695000, 109093) = 0
  openat("/usr/lib/locale/locale-archive", CLOEXEC) = 3
  mmap(0, 217749968, READ, PRIVATE, 3, 0) = 0x7ff60f523000
  #
  # vim ~/.perfconfig
  #
  # perf config
  llvm.dump-obj=true
  trace.add_events=/home/acme/git/perf/tools/perf/examples/bpf/augmented_raw_syscalls.o
  trace.show_zeros=yes
  trace.show_duration=no
  trace.no_inherit=yes
  trace.show_timestamp=no
  trace.show_arg_names=no
  trace.args_alignment=0
  trace.string_quote="
  trace.show_prefix=yes
  #
  #
  # trace -e *map,open*,*seek sleep 1
  openat(AT_FDCWD, "/etc/ld.so.cache", O_CLOEXEC) = 3
  mmap(0, 109093, PROT_READ, MAP_PRIVATE, 3, 0) = 0x7f7ebbe59000
  openat(AT_FDCWD, "/lib64/libc.so.6", O_CLOEXEC) = 3
  lseek(3, 792, SEEK_SET) = 792
  mmap(0, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS) = 0x7f7ebbe57000
  lseek(3, 792, SEEK_SET) = 792
  lseek(3, 864, SEEK_SET) = 864
  mmap(0, 1857568, PROT_READ, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x7f7ebbc91000
  mmap(0x7f7ebbcb3000, 1363968, PROT_EXEC|PROT_READ, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 139264) = 0x7f7ebbcb3000
  mmap(0x7f7ebbe00000, 311296, PROT_READ, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 1503232) = 0x7f7ebbe00000
  mmap(0x7f7ebbe4d000, 24576, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 1814528) = 0x7f7ebbe4d000
  mmap(0x7f7ebbe53000, 14368, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS) = 0x7f7ebbe53000
  munmap(0x7f7ebbe59000, 109093) = 0
  openat(AT_FDCWD, "/usr/lib/locale/locale-archive", O_CLOEXEC) = 3
  mmap(0, 217749968, PROT_READ, MAP_PRIVATE, 3, 0) = 0x7f7eaece7000
  #

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Luis Cláudio Gonçalves <lclaudio@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Wang Nan <wangnan0@huawei.com>
Link: https://lkml.kernel.org/n/tip-mtn1i4rjowjl72trtnbmvjd4@git.kernel.orgSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

So that the user, in an upcoming patch, can select printing it to get
the full string as used in the source code, not one with a common prefix
chopped off so as to make the output more compact.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Luis Cláudio Gonçalves <lclaudio@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Wang Nan <wangnan0@huawei.com>
Link: https://lkml.kernel.org/n/tip-zypczc88gzbmeqx7b372s138@git.kernel.orgSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

To match 'strace' output, helping with upcoming regression tests
comparing both outputs.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Luis Cláudio Gonçalves <lclaudio@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Wang Nan <wangnan0@huawei.com>
Link: https://lkml.kernel.org/n/tip-jab52t1dcuh6vlztqle9g7u9@git.kernel.orgSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

Since the start 'perf trace' aligns the parens enclosing the list of
syscall args to align the syscall results, allow this to be
configurable, keeping the default of 70. Using:

  # perf config
  llvm.dump-obj=true
  trace.add_events=/home/acme/git/perf/tools/perf/examples/bpf/augmented_raw_syscalls.o
  trace.show_zeros=yes
  trace.show_duration=no
  trace.no_inherit=yes
  trace.show_timestamp=no
  trace.show_arg_names=no
  trace.args_alignment=0
  # trace -e open*,close,*sleep sleep 1
  openat(CWD, /etc/ld.so.cache, CLOEXEC) = 3
  close(3) = 0
  openat(CWD, /lib64/libc.so.6, CLOEXEC) = 3
  close(3) = 0
  openat(CWD, /usr/lib/locale/locale-archive, CLOEXEC) = 3
  close(3) = 0
  nanosleep(0x7ffc00de66f0, 0) = 0
  close(1) = 0
  close(2) = 0
  #

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Luis Cláudio Gonçalves <lclaudio@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Wang Nan <wangnan0@huawei.com>
Link: https://lkml.kernel.org/n/tip-r8cbhoz1lr5npq9tutpvoigr@git.kernel.orgSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

To show just the values:

Default:

  # trace -e open*,close,*sleep sleep 1
  openat(dfd: CWD, filename: /etc/ld.so.cache, flags: CLOEXEC           ) = 3
  close(fd: 3                                                           ) = 0
  openat(dfd: CWD, filename: /lib64/libc.so.6, flags: CLOEXEC           ) = 3
  close(fd: 3                                                           ) = 0
  openat(dfd: CWD, filename: /usr/lib/locale/locale-archive, flags: CLOEXEC) = 3
  close(fd: 3                                                           ) = 0
  nanosleep(rqtp: 0x7ffc0c4ea0d0, rmtp: 0                               ) = 0
  close(fd: 1                                                           ) = 0
  close(fd: 2                                                           ) = 0
  #

Remove it:

  # perf config trace.show_arg_names=no
  # trace -e open*,close,*sleep sleep 1
  openat(CWD, /etc/ld.so.cache, CLOEXEC                                 ) = 3
  close(3                                                               ) = 0
  openat(CWD, /lib64/libc.so.6, CLOEXEC                                 ) = 3
  close(3                                                               ) = 0
  openat(CWD, /usr/lib/locale/locale-archive, CLOEXEC                   ) = 3
  close(3                                                               ) = 0
  nanosleep(0x7ffced3a8c40, 0                                           ) = 0
  close(1                                                               ) = 0
  close(2                                                               ) = 0
  #

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Luis Cláudio Gonçalves <lclaudio@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Wang Nan <wangnan0@huawei.com>
Link: https://lkml.kernel.org/n/tip-ta9tbdwgodpw719sr2bjm8eb@git.kernel.orgSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

  # trace -e open*,close,*sleep sleep 1
     0.000 openat(dfd: CWD, filename: /etc/ld.so.cache, flags: CLOEXEC           ) = 3
     0.016 close(fd: 3                                                           ) = 0
     0.024 openat(dfd: CWD, filename: /lib64/libc.so.6, flags: CLOEXEC           ) = 3
     0.074 close(fd: 3                                                           ) = 0
     0.235 openat(dfd: CWD, filename: /usr/lib/locale/locale-archive, flags: CLOEXEC) = 3
     0.251 close(fd: 3                                                           ) = 0
     0.285 nanosleep(rqtp: 0x7ffd68e6d620, rmtp: 0                               ) = 0
  1000.386 close(fd: 1                                                           ) = 0
  1000.395 close(fd: 2                                                           ) = 0
  #

  # perf config trace.show_timestamp=no
  # trace -e open*,close,*sleep sleep 1
  openat(dfd: CWD, filename: /etc/ld.so.cache, flags: CLOEXEC           ) = 3
  close(fd: 3                                                           ) = 0
  openat(dfd: CWD, filename: /lib64/libc.so.6, flags: CLOEXEC           ) = 3
  close(fd: 3                                                           ) = 0
  openat(dfd: CWD, filename: , flags: CLOEXEC                           ) = 3
  close(fd: 3                                                           ) = 0
  nanosleep(rqtp: 0x7fffa79c38e0, rmtp: 0                               ) = 0
  close(fd: 1                                                           ) = 0
  close(fd: 2                                                           ) = 0
  #

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Luis Cláudio Gonçalves <lclaudio@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Wang Nan <wangnan0@huawei.com>
Link: https://lkml.kernel.org/n/tip-mjjnicy48367jah6ls4k0nk8@git.kernel.orgSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

I.f. if children should inherit the parent perf_event configuration,
i.e. if we should trace children as well or just the parent.

The default is to follow children, to disable this and have a behaviour
similar to strace, set this config option or use the --no_inherit 'perf
trace' option.

E.g.:

Default:

  # perf config trace.no_inherit
  # trace -e clone,*sleep time sleep 1
     0.000 time/21107 clone(clone_flags: CHILD_CLEARTID|CHILD_SETTID|0x11, newsp: 0, child_tidptr: 0x7f7b8f9ae810) = 21108 (time)
         ? time/21108  ... [continued]: clone()
     0.691 sleep/21108 nanosleep(rqtp: 0x7ffed01d0540, rmtp: 0                               ) = 0
  0.00user 0.00system 0:01.00elapsed 0%CPU (0avgtext+0avgdata 1988maxresident)k
  0inputs+0outputs (0major+76minor)pagefaults 0swaps
  #

Disable it:

  # trace -e clone,*sleep time sleep 1
     0.000 clone(clone_flags: CHILD_CLEARTID|CHILD_SETTID|0x11, newsp: 0, child_tidptr: 0x7ff41e100810) = 21414 (time)
  0.00user 0.00system 0:01.00elapsed 0%CPU (0avgtext+0avgdata 1964maxresident)k
  0inputs+0outputs (0major+76minor)pagefaults 0swaps
  #

Notice that since there is just one thread, the "comm/TID" column is
suppressed.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Luis Cláudio Gonçalves <lclaudio@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Wang Nan <wangnan0@huawei.com>
Link: https://lkml.kernel.org/n/tip-thd8s16pagyza71ufi5vjlan@git.kernel.orgSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

More convenient thah having to recall what letter is about
showing/listing/dumping the configuration, i.e. no arguments means
-l/--list:

  # perf config
  llvm.dump-obj=true
  trace.default_events=/home/acme/git/perf/tools/perf/examples/bpf/augmented_raw_syscalls.o
  trace.show_zeros=yes
  trace.show_duration=no
  # perf config -l
  llvm.dump-obj=true
  trace.default_events=/home/acme/git/perf/tools/perf/examples/bpf/augmented_raw_syscalls.o
  trace.show_zeros=yes
  trace.show_duration=no
  # perf config -h

   Usage: perf config [<file-option>] [options] [section.name[=value] ...]

      -l, --list            show current config variables
          --system          use system config file
          --user            use user config file

  #

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Luis Cláudio Gonçalves <lclaudio@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Taeung Song <treeze.taeung@gmail.com>
Cc: Wang Nan <wangnan0@huawei.com>
Link: https://lkml.kernel.org/n/tip-z2n63avz6tliqb5gmu4l1dti@git.kernel.orgSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

  # perf config trace.show_duration=no
  # perf config -l | grep trace
  trace.default_events=/home/acme/git/perf/tools/perf/examples/bpf/augmented_raw_syscalls.o
  trace.show_zeros=true
  trace.show_duration=no
  # trace -e *sleep sleep 1
     0.000 sleep/8729 nanosleep(rqtp: 0x7ffcb0b4c940, rmtp: 0) = 0
  # perf config trace.show_duration=yes
  # trace -e *sleep sleep 1
     0.000 (1000.212 ms): sleep/8735 nanosleep(rqtp: 0x7ffca15fa770, rmtp: 0) = 0
  #

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Luis Cláudio Gonçalves <lclaudio@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Wang Nan <wangnan0@huawei.com>
Link: https://lkml.kernel.org/n/tip-2c7h1m8fhzb9puxtj9nlevi8@git.kernel.orgSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

The default so far, since we show argument names followed by its values,
was to make the output more compact by suppressing most zeroed args.

Make this configurable so that users can choose what best suit their
needs.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Luis Cláudio Gonçalves <lclaudio@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Wang Nan <wangnan0@huawei.com>
Link: https://lkml.kernel.org/n/tip-q0gxws02ygodh94o0hzim5xd@git.kernel.orgSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

To add augmented_raw_syscalls to the events speficied by the user, or be
the only one if no events were specified by the user, one can add this
to perfconfig:

  # cat ~/.perfconfig
  [trace]
	  add_events = /home/acme/git/perf/tools/perf/examples/bpf/augmented_raw_syscalls.o
  #

I.e. pre-compile the augmented_raw_syscalls.c BPF program and make it
always load, this way:

  # perf trace -e open* cat /etc/passwd > /dev/null
     0.000 ( 0.013 ms): cat/31557 openat(dfd: CWD, filename: /etc/ld.so.cache, flags: CLOEXEC) = 3
     0.035 ( 0.007 ms): cat/31557 openat(dfd: CWD, filename: /lib64/libc.so.6, flags: CLOEXEC) = 3
     0.353 ( 0.009 ms): cat/31557 openat(dfd: CWD, filename: /usr/lib/locale/locale-archive, flags: CLOEXEC) = 3
     0.424 ( 0.006 ms): cat/31557 openat(dfd: CWD, filename: /etc/passwd) = 3
  #

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Luis Cláudio Gonçalves <lclaudio@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Wang Nan <wangnan0@huawei.com>
Link: https://lkml.kernel.org/n/tip-0lgj7vh64hg3ce44gsmvj7ud@git.kernel.orgSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

We're not using that puts() thing, and thus we don't need to define the
__bpf_stdout__ map, reducing the setup time.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Luis Cláudio Gonçalves <lclaudio@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Wang Nan <wangnan0@huawei.com>
Link: https://lkml.kernel.org/n/tip-3452xgatncpil7v22minkwbo@git.kernel.orgSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

The exception packet appears as one element with 'elem_type' ==
OCSD_GEN_TRC_ELEM_EXCEPTION or OCSD_GEN_TRC_ELEM_EXCEPTION_RET, which is
present for exception entry and exit respectively.  The decoder sets the
packet fields 'packet->exc' and 'packet->exc_ret' to indicate the
exception packets; but exception packets don't have a dedicated sample
type and shares the same sample type CS_ETM_RANGE with normal
instruction packets.

As a result, the exception packets are taken as normal instruction
packets and this introduces confusion in mixing different packet types.
Furthermore, these instruction range packets will be processed for
branch samples only when 'packet->last_instr_taken_branch' is true,
otherwise they will be omitted, this can introduce a mess for exception
and exception returning due to not having the complete address range
info for context switching.

To process exception packets properly, this patch introduces two new
sample types: CS_ETM_EXCEPTION and CS_ETM_EXCEPTION_RET; these two types
of packets will be handled by cs_etm__exception().  The function
cs_etm__exception() forces setting the previous CS_ETM_RANGE packet flag
'prev_packet->last_instr_taken_branch' to true, this matches well with
the program flow when the exception is trapped from user space to kernel
space, no matter if the most recent flow has branch taken or not; this
is also safe for returning to user space after exception handling.

After exception packets have their own sample type, the packet fields
'packet->exc' and 'packet->exc_ret' aren't needed anymore, so remove
them.
Signed-off-by: Leo Yan <leo.yan@linaro.org>
Reviewed-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Mike Leach <mike.leach@linaro.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Robert Walker <robert.walker@arm.com>
Cc: coresight ml <coresight@lists.linaro.org>
Cc: linux-arm-kernel@lists.infradead.org
Link: http://lkml.kernel.org/r/1544513908-16805-9-git-send-email-leo.yan@linaro.orgSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

If the decoder outputs an EO_TRACE element, it means the end of the
trace buffer; this is a discontinuity and in this case the end of trace
data needs to be saved.

This patch generates a CS_ETM_DISCONTINUITY packet for the EO_TRACE
element hereby flushing the end of trace data in cs-etm.c.
Signed-off-by: Leo Yan <leo.yan@linaro.org>
Reviewed-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Mike Leach <mike.leach@linaro.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Robert Walker <robert.walker@arm.com>
Cc: coresight@lists.linaro.org
Cc: linux-arm-kernel@lists.infradead.org
Link: http://lkml.kernel.org/r/1544513908-16805-8-git-send-email-leo.yan@linaro.orgSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

The CoreSight tracer driver might insert barrier packets between
different buffers, thus the decoder can spot the boundaries based on the
barrier packet; it is possible for the decoder to hit a barrier packet
and emit a NO_SYNC element, then the decoder will find a periodic
synchronisation point inside that next trace block that starts the trace
again but does not have the TRACE_ON element as indicator - usually
because this trace block has wrapped the buffer so we have lost the
original point when the trace was enabled.

In the first case it causes the insertion of a OCSD_GEN_TRC_ELEM_NO_SYNC
in the middle of the tracing stream, but as we were not handling the
NO_SYNC element properly this ends up making users miss the
discontinuity indications.

Though OCSD_GEN_TRC_ELEM_NO_SYNC is different from CS_ETM_TRACE_ON when
output from the decoder, both indicate that the trace data is
discontinuous; this patch treats OCSD_GEN_TRC_ELEM_NO_SYNC as a trace
discontinuity and generates a CS_ETM_DISCONTINUITY packet for it, so
cs-etm can handle the discontinuity for this case, finally it saves the
last trace data for the previous trace block and restart samples for the
new block.
Signed-off-by: Leo Yan <leo.yan@linaro.org>
Reviewed-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Mike Leach <mike.leach@linaro.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Robert Walker <robert.walker@arm.com>
Cc: coresight ml <coresight@lists.linaro.org>
Cc: linux-arm-kernel@lists.infradead.org
Link: http://lkml.kernel.org/r/1544513908-16805-7-git-send-email-leo.yan@linaro.orgSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

TRACE_ON element is used at the beginning of trace, it also can be
appeared in the middle of trace data to indicate discontinuity; for
example, it's possible to see multiple TRACE_ON elements in the trace
stream if the trace is being limited by address range filtering.

Furthermore, except TRACE_ON element is for discontinuity, NO_SYNC and
EO_TRACE also can be used to indicate discontinuity, though they are
used for different scenarios for which the trace is interrupted.

This patch renames sample type CS_ETM_TRACE_ON to CS_ETM_DISCONTINUITY,
firstly the new name describes more closely the purpose of the packet;
secondly this is a preparation for other output elements which also
cause the trace discontinuity thus they can share the same one packet
type.
Signed-off-by: Leo Yan <leo.yan@linaro.org>
Reviewed-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Mike Leach <mike.leach@linaro.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Robert Walker <robert.walker@arm.com>
Cc: coresight@lists.linaro.org
Cc: linux-arm-kernel@lists.infradead.org
Link: http://lkml.kernel.org/r/1544513908-16805-6-git-send-email-leo.yan@linaro.orgSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

The values in enumeration cs_etm_sample_type are defined with setting
bit N for each packet type, this is not suggested in the usual case.

This patch refactor cs_etm_sample_type by converting from bit shifting
values to continuous numbers.
Signed-off-by: Leo Yan <leo.yan@linaro.org>
Reviewed-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Mike Leach <mike.leach@linaro.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Robert Walker <robert.walker@arm.com>
Cc: coresight@lists.linaro.org
Cc: linux-arm-kernel@lists.infradead.org
Link: http://lkml.kernel.org/r/1544513908-16805-5-git-send-email-leo.yan@linaro.orgSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

cs_etm_decoder::trace_on is being assigned when TRACE_ON or NO_SYNC
element is coming, but it is never used hence it is redundant and can
be removed.

So let's remove 'trace_on' field from cs_etm_decoder struct.
Suggested-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Leo Yan <leo.yan@linaro.org>
Reviewed-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Cc: Mike Leach <mike.leach@linaro.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Robert Walker <robert.walker@arm.com>
Cc: coresight@lists.linaro.org
Cc: linux-arm-kernel@lists.infradead.org
Link: http://lkml.kernel.org/r/1544513908-16805-4-git-send-email-leo.yan@linaro.orgSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

At the end of trace buffer handling, function cs_etm__flush() is invoked
to flush any remaining branch stack entries.  As a side effect, it also
generates branch sample, because the 'etmq->packet' doesn't contains any
new coming packet but point to one stale packet after packets swapping,
so it wrongly makes synthesize branch samples with stale packet info.

We could review below detailed flow which causes issue:

  Packet1: start_addr=0xffff000008b1fbf0 end_addr=0xffff000008b1fbfc
  Packet2: start_addr=0xffff000008b1fb5c end_addr=0xffff000008b1fb6c

  step 1: cs_etm__sample():
	sample: ip=(0xffff000008b1fbfc-4) addr=0xffff000008b1fb5c

  step 2: flush packet in cs_etm__run_decoder():
	cs_etm__run_decoder()
	  `-> err = cs_etm__flush(etmq, false);
	sample: ip=(0xffff000008b1fb6c-4) addr=0xffff000008b1fbf0

Packet1 and packet2 are two continuous packets, when packet2 is the new
coming packet, cs_etm__sample() generates branch sample for these two
packets and use [packet1::end_addr - 4 => packet2::start_addr] as branch
jump flow, thus we can see the first generated branch sample in step 1.
At the end of cs_etm__sample() it swaps packets so 'etm->prev_packet'=
packet2 and 'etm->packet'=packet1, so far it's okay for branch sample.

If packet2 is the last one packet in trace buffer, even there have no
any new coming packet, cs_etm__run_decoder() invokes cs_etm__flush() to
flush branch stack entries as expected, but it also generates branch
samples by taking 'etm->packet' as a new coming packet, thus the branch
jump flow is as [packet2::end_addr - 4 =>  packet1::start_addr]; this
is the second sample which is generated in step 2.  So actually the
second sample is a stale sample and we should not generate it.

This patch introduces a new function cs_etm__end_block(), at the end of
trace block this function is invoked to only flush branch stack entries
and thus can avoid to generate branch sample for stale packet.
Signed-off-by: Leo Yan <leo.yan@linaro.org>
Reviewed-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Mike Leach <mike.leach@linaro.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Robert Walker <robert.walker@arm.com>
Cc: coresight@lists.linaro.org
Cc: linux-arm-kernel@lists.infradead.org
Link: http://lkml.kernel.org/r/1544513908-16805-3-git-send-email-leo.yan@linaro.orgSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

The structure cs_etm_queue uses 'prev_packet' to point to previous
packet, this can be used to combine with new coming packet to generate
samples.

In function cs_etm__flush() it swaps packets only when the flag
'etm->synth_opts.last_branch' is true, this means that it will not swap
packets if without option '--itrace=il' to generate last branch entries;
thus for this case the 'prev_packet' doesn't point to the correct
previous packet and the stale packet still will be used to generate
sequential sample.  Thus if dump trace with 'perf script' command we can
see the incorrect flow with the stale packet's address info.

This patch corrects packets swapping in cs_etm__flush(); except using
the flag 'etm->synth_opts.last_branch' it also checks the another flag
'etm->sample_branches', if any flag is true then it swaps packets so can
save correct content to 'prev_packet'.  Finally this can fix the wrong
program flow dumping issue.

The patch has a minor refactoring to use 'etm->synth_opts.last_branch'
instead of 'etmq->etm->synth_opts.last_branch' for condition checking,
this is consistent with that is done in cs_etm__sample().
Signed-off-by: Leo Yan <leo.yan@linaro.org>
Reviewed-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Mike Leach <mike.leach@linaro.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Robert Walker <robert.walker@arm.com>
Cc: coresight@lists.linaro.org
Cc: linux-arm-kernel@lists.infradead.org
Link: http://lkml.kernel.org/r/1544513908-16805-2-git-send-email-leo.yan@linaro.orgSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

We'll start adding more perf-syscall stuff, so lets do this prep step so
that the next ones are just about adding more fields.

Cc: Adrian Hunter <adrian.hunter@intel.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-vac4sn1ns1vj4y07lzj7y4b8@git.kernel.orgSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

We'll start adding more perf-syscall stuff, so lets do this prep step so
that the next ones are just about adding more fields.

Run it with the .c file once to cache the .o file:

  # trace --filter-pids 2834,2199 -e openat,augmented_raw_syscalls.c
  LLVM: dumping augmented_raw_syscalls.o
       0.000 ( 0.021 ms): tmux: server/4952 openat(dfd: CWD, filename: /proc/5691/cmdline                         ) = 11
     349.807 ( 0.040 ms): DNS Res~er #39/11082 openat(dfd: CWD, filename: /etc/hosts, flags: CLOEXEC                 ) = 44
    4988.759 ( 0.052 ms): gsd-color/2431 openat(dfd: CWD, filename: /etc/localtime                             ) = 18
    4988.976 ( 0.029 ms): gsd-color/2431 openat(dfd: CWD, filename: /etc/localtime                             ) = 18
  ^C[root@quaco bpf]#

From now on, we can use just the newly built .o file, skipping the
compilation step for a faster startup:

  # trace --filter-pids 2834,2199 -e openat,augmented_raw_syscalls.o
       0.000 ( 0.046 ms): DNS Res~er #39/11088 openat(dfd: CWD, filename: /etc/hosts, flags: CLOEXEC                 ) = 44
    1946.408 ( 0.190 ms): systemd/1 openat(dfd: CWD, filename: /proc/1071/cgroup, flags: CLOEXEC          ) = 20
    1946.792 ( 0.215 ms): systemd/1 openat(dfd: CWD, filename: /proc/954/cgroup, flags: CLOEXEC           ) = 20
  ^C#

Now on to do the same in the builtin-trace.c side of things.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: https://lkml.kernel.org/n/tip-k8mwu04l8es29rje5loq9vg7@git.kernel.orgSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

So that we don't always carry that __bpf_output__ map, leaving that to
the scripts wanting to use that facility.

'perf trace' will be changed to look if that map is present and only
setup the bpf-output events if so.

Cc: Adrian Hunter <adrian.hunter@intel.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-azwys8irxqx9053vpajr0k5h@git.kernel.orgSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

Just another map, this time an BPF_MAP_TYPE_ARRAY, stating with
one bool per syscall, stating if it should be filtered or not.

So, with a pre-built augmented_raw_syscalls.o file, we use:

  # perf trace -e open*,augmented_raw_syscalls.o
     0.000 ( 0.016 ms): DNS Res~er #37/29652 openat(dfd: CWD, filename: /etc/hosts, flags: CLOEXEC                 ) = 138
   187.039 ( 0.048 ms): gsd-housekeepi/2436 openat(dfd: CWD, filename: /etc/fstab, flags: CLOEXEC                 ) = 11
   187.348 ( 0.041 ms): gsd-housekeepi/2436 openat(dfd: CWD, filename: /proc/self/mountinfo, flags: CLOEXEC       ) = 11
   188.793 ( 0.036 ms): gsd-housekeepi/2436 openat(dfd: CWD, filename: /proc/self/mountinfo, flags: CLOEXEC       ) = 11
   189.803 ( 0.029 ms): gsd-housekeepi/2436 openat(dfd: CWD, filename: /proc/self/mountinfo, flags: CLOEXEC       ) = 11
   190.774 ( 0.027 ms): gsd-housekeepi/2436 openat(dfd: CWD, filename: /proc/self/mountinfo, flags: CLOEXEC       ) = 11
   284.620 ( 0.149 ms): DataStorage/3076 openat(dfd: CWD, filename: /home/acme/.mozilla/firefox/ina67tev.default/SiteSecurityServiceState.txt, flags: CREAT|TRUNC|WRONLY, mode: IRUGO|IWUSR|IWGRP) = 167
  ^C#

What is it that this gsd-housekeeping thingy needs to open
/proc/self/mountinfo four times periodically? :-)

This map will be extended to tell per-syscall parameters, i.e. how many
bytes to copy per arg, using the function signature to get the types and
then the size of those types, via BTF.

Cc: Adrian Hunter <adrian.hunter@intel.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-cy222g9ucvnym3raqvxp0hpg@git.kernel.orgSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

So when we do something like:

   # perf trace -e open*,augmented_raw_syscalls.o

We need to set trace->trace_syscalls because there is logic that use
that when mixing strace-like output with other events, such as scheduler
tracepoints, but with that set we ended up having multiple
raw_syscalls:sys_{enter,exit} setup, which garbled the output, so
check if trace->augmented_raw_syscalls is set and avoid the two extra
tracepoints.

Cc: Adrian Hunter <adrian.hunter@intel.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-kjmnbrlgu0c38co1ye8egbsb@git.kernel.orgSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

Rename it to trace__set_ev_qualifier_tp_filter(), as this just sets up
tracepoint filters on the raw_syscalls:sys_{enter,exit} tracepoints, and
since we're going to do the same for the augmented_raw_syscalls
codepath, when used, rename it to clarify.

Cc: Adrian Hunter <adrian.hunter@intel.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-8bjsul8x7osw7nxjodnyfn14@git.kernel.orgSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

So we could propagate distro flags into libperf-jvmti.so library.
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20181212132940.840-1-jolsa@kernel.orgSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

So that the user can specify outside LDFLAGS values.

Keeping the CFLAGS in there as well, so we don't break existing scripts.
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Acked-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Cc: Herton Krzesinski <herton@redhat.com>
Cc: Tzvetomir Stoyanov (VMware) <tz.stoyanov@gmail.com>
Link: http://lkml.kernel.org/r/20181212091214.GC17489@kravaSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

To avoid this warning:

    CC       /tmp/build/perf/util/s390-cpumsf.o
  util/s390-cpumsf.c: In function 's390_cpumsf_samples':
  util/s390-cpumsf.c:508:3: warning: format '%llx' expects argument of type 'long long unsigned int', but argument 4 has type 'off_t' [-Wformat=]
     pr_err("[%#08" PRIx64 "] Invalid AUX trailer entry TOD clock base\n",
     ^

Now the various Android cross toolchains used in the perf tools
container test builds are all clean and we can remove this:

  export EXTRA_MAKE_ARGS="WERROR=0"

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Thomas Richter <tmricht@linux.ibm.com>
Link: https://lkml.kernel.org/n/tip-5rav4ccyb0sjciysz2i4p3sx@git.kernel.orgSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

There are systems such as the Android NDK API level 24 has the
open_memstream() function but doesn't provide a prototype, adding noise
to the build:

  builtin-timechart.c: In function 'cat_backtrace':
  builtin-timechart.c:486:2: warning: implicit declaration of function 'open_memstream' [-Wimplicit-function-declaration]
    FILE *f = open_memstream(&p, &p_len);
    ^
  builtin-timechart.c:486:2: warning: nested extern declaration of 'open_memstream' [-Wnested-externs]
  builtin-timechart.c:486:12: warning: initialization makes pointer from integer without a cast
    FILE *f = open_memstream(&p, &p_len);
              ^

Define a LACKS_OPEN_MEMSTREAM_PROTOTYPE define so that code needing that
can get a prototype.

Checked in the bionic git repo to be available since level 23:

https://android.googlesource.com/platform/bionic/+/master/libc/include/stdio.h#241

  FILE* open_memstream(char** __ptr, size_t* __size_ptr) __INTRODUCED_IN(23);

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: https://lkml.kernel.org/n/tip-343ashae97e5bq6vizusyfno@git.kernel.orgSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

Reducing this noise when cross building to the Android NDK:

  util/header.c: In function 'perf_header__fprintf_info':
  util/header.c:2710:45: warning: pointer targets in passing argument 1 of 'ctime' differ in signedness [-Wpointer-sign]
    fprintf(fp, "# captured on    : %s", ctime(&st.st_ctime));
                                               ^
  In file included from util/../perf.h:5:0,
                   from util/evlist.h:11,
                   from util/header.c:22:
  /opt/android-ndk-r15c/platforms/android-26/arch-arm/usr/include/time.h:81:14: note: expected 'const time_t *' but argument is of type 'long unsigned int *'
   extern char* ctime(const time_t*) __LIBC_ABI_PUBLIC__;
                ^

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: https://lkml.kernel.org/n/tip-6bz74zp080yhmtiwb36enso9@git.kernel.orgSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

There are systems such as the Android NDK API level 24 has the
sigqueue() function but doesn't provide a prototype, adding noise to the
build:

  util/evlist.c: In function 'perf_evlist__prepare_workload':
  util/evlist.c:1494:4: warning: implicit declaration of function 'sigqueue' [-Wimplicit-function-declaration]
      if (sigqueue(getppid(), SIGUSR1, val))
      ^
  util/evlist.c:1494:4: warning: nested extern declaration of 'sigqueue' [-Wnested-externs]

Define a LACKS_SIGQUEUE_PROTOTYPE define so that code needing that can
get a prototype.

Checked in the bionic git repo to be available since level 23:

https://android.googlesource.com/platform/bionic/+/master/libc/include/signal.h#123

  int sigqueue(pid_t __pid, int __signal, const union sigval __value) __INTRODUCED_IN(23);

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: https://lkml.kernel.org/n/tip-lmhpev1uni9kdrv7j29glyov@git.kernel.orgSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>