Being const + weak breaks with some compilers that constant-propagate
from the weak symbol. This behavior is outside of the specification, but
in LLVM is chosen to match GCC's behavior.

LLVM's implementation was set in this patch:

  https://github.com/llvm/llvm-project/commit/f49573d1eedcf1e44893d5a062ac1b72c8419646

A const + weak symbol is set to be weak_odr:

  https://llvm.org/docs/LangRef.html

ODR is one definition rule, and given there is one constant definition
constant-propagation is possible. It is possible to get this code to
miscompile with LLVM when applying link time optimization. As compilers
become more aggressive, this is likely to break in more instances.

Move the definition of sample_reg_masks to the conditional part of
perf_regs.h and guard usage with HAVE_PERF_REGS_SUPPORT. This avoids the
weak symbol.

Fix an issue when HAVE_PERF_REGS_SUPPORT isn't defined from patch v1.
In v3, add perf_regs.c for architectures that HAVE_PERF_REGS_SUPPORT but
don't declare sample_regs_masks.

Further notes:

Jiri asked:

  "Is this just a precaution or you actualy saw some breakage?"

Ian answered:

  "We saw a breakage with clang with thinlto enabled for linking. Our
   compiler team had recently seen, and were surprised by, a similar issue
   and were able to dig out the weak ODR issue."
Signed-off-by: Ian Rogers <irogers@google.com>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Cc: Albert Ou <aou@eecs.berkeley.edu>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Alexey Budankov <alexey.budankov@linux.intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: clang-built-linux@googlegroups.com
Cc: Guo Ren <guoren@kernel.org>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: linux-riscv@lists.infradead.org
Cc: Mao Han <han_mao@c-sky.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Palmer Dabbelt <palmer@sifive.com>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lore.kernel.org/lkml/20191001003623.255186-1-irogers@google.comSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

Continuing from the previous cset comment, now that filter expression
works:

  # perf trace -e msr:* --filter="msr!=FS_BASE && msr != IA32_TSC_DEADLINE && msr != 0x830 && msr != 0x83f && msr !=IA32_SPEC_CTRL" --filter-pids 3750
     0.000 Timer/5033 msr:write_msr(msr: SYSCALL_MASK, val: 292608)
     0.009 Timer/5033 msr:write_msr(msr: LSTAR, val: -1398800368)
     0.010 Timer/5033 msr:write_msr(msr: TSC_AUX, val: 4)
     0.050 :0/0 msr:read_msr(msr: IA32_TSC_ADJUST)
    45.661 gnome-terminal/12595 msr:write_msr(msr: SYSCALL_MASK, val: 292608)
    45.672 gnome-terminal/12595 msr:write_msr(msr: LSTAR, val: -1398800368)
    45.675 gnome-terminal/12595 msr:write_msr(msr: TSC_AUX, val: 3)
    54.852 :0/0 msr:read_msr(msr: IA32_TSC_ADJUST)
   130.508 Timer/4050 msr:write_msr(msr: SYSCALL_MASK, val: 292608)
   130.527 Timer/4050 msr:write_msr(msr: LSTAR, val: -1398800368)
   130.531 Timer/4050 msr:write_msr(msr: TSC_AUX, val: 3)
   140.924 :0/0 msr:read_msr(msr: IA32_TSC_ADJUST)
   164.738 :0/0 msr:read_msr(msr: IA32_TSC_ADJUST)
   603.578 :0/0 msr:read_msr(msr: IA32_TSC_ADJUST)
   620.809 :0/0 msr:read_msr(msr: IA32_TSC_ADJUST)
   690.115 JS Watchdog/4259 msr:write_msr(msr: SYSCALL_MASK, val: 292608)
   690.136 JS Watchdog/4259 msr:write_msr(msr: LSTAR, val: -1398800368)
   690.141 JS Watchdog/4259 msr:write_msr(msr: TSC_AUX, val: 3)
   690.186 :0/0 msr:read_msr(msr: IA32_TSC_ADJUST)
   759.016 :0/0 msr:read_msr(msr: IA32_TSC_ADJUST)
^C[root@quaco ~]#

Or look at the first 3 write_msr events for that IA32_TSC_DEADLINE to learn why
it happens so often:

  # perf trace --max-events=3 --max-stack=8 -e msr:* --filter="msr==IA32_TSC_DEADLINE" --filter-pids 3750
     0.000 :0/0 msr:write_msr(msr: IA32_TSC_DEADLINE, val: 19296732550862)
                                       do_trace_write_msr ([kernel.kallsyms])
                                       do_trace_write_msr ([kernel.kallsyms])
                                       lapic_next_deadline ([kernel.kallsyms])
                                       clockevents_program_event ([kernel.kallsyms])
                                       hrtimer_interrupt ([kernel.kallsyms])
                                       smp_apic_timer_interrupt ([kernel.kallsyms])
                                       apic_timer_interrupt ([kernel.kallsyms])
                                       cpuidle_enter_state ([kernel.kallsyms])
    32.646 :0/0 msr:write_msr(msr: IA32_TSC_DEADLINE, val: 19296800134158)
                                       do_trace_write_msr ([kernel.kallsyms])
                                       do_trace_write_msr ([kernel.kallsyms])
                                       lapic_next_deadline ([kernel.kallsyms])
                                       clockevents_program_event ([kernel.kallsyms])
                                       hrtimer_start_range_ns ([kernel.kallsyms])
                                       tick_nohz_restart_sched_tick ([kernel.kallsyms])
                                       tick_nohz_idle_exit ([kernel.kallsyms])
                                       do_idle ([kernel.kallsyms])
    32.802 :0/0 msr:write_msr(msr: IA32_TSC_DEADLINE, val: 19297507436922)
                                       do_trace_write_msr ([kernel.kallsyms])
                                       do_trace_write_msr ([kernel.kallsyms])
                                       lapic_next_deadline ([kernel.kallsyms])
                                       clockevents_program_event ([kernel.kallsyms])
                                       hrtimer_try_to_cancel ([kernel.kallsyms])
                                       hrtimer_cancel ([kernel.kallsyms])
                                       tick_nohz_restart_sched_tick ([kernel.kallsyms])
                                       tick_nohz_idle_exit ([kernel.kallsyms])
  #

And if some of the strings can't be found:

  # trace -e msr:* --filter="msr!=SPECULATIVE_EXECUTION_PROBLEMS_SOLUTION && msr != IA32_TSC_DEADLINE && msr != 0x830 && msr != 0x83f && msr !=IA32_SPEC_CTRL" --filter-pids 3750
  "SPECULATIVE_EXECUTION_PROBLEMS_SOLUTION" not found for "msr" in "msr:read_msr", can't set filter "(msr!=SPECULATIVE_EXECUTION_PROBLEMS_SOLUTION && msr != IA32_TSC_DEADLINE && msr != 0x830 && msr != 0x83f && msr !=IA32_SPEC_CTRL) && (common_pid != 28131 && common_pid != 3750)"
  #

Next step is to automatically wire up the pre-existing strarrays, which there
are quite a few.

The strtoul() methods will be further enhanced to allow for looking at other
arguments in a syscall/tracepoint, just like going from integer to string
(scnprintf methods), so that those "val" lines for the msr tracepoints can be
properly formatted or even resolved into some string.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Brendan Gregg <brendan.d.gregg@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Luis Cláudio Gonçalves <lclaudio@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: https://lkml.kernel.org/n/tip-4qaai5iqjgefd11k4ddm7qg8@git.kernel.orgSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

So that one can try things like:

  # perf trace -e msr:* --filter="msr!=FS_BASE && msr != IA32_TSC_DEADLINE && msr != 0x830 && msr != 0x83f && msr !=IA32_SPEC_CTRL" --filter-pids 3750

That, at this point in the patchset, without any strtoul in place for
tracepoint arguments, will result in:

  No resolver (strtoul) for "msr" in "msr:read_msr", can't set filter "(msr!=FS_BASE && msr != IA32_TSC_DEADLINE && msr != 0x830 && msr != 0x83f && msr !=IA32_SPEC_CTRL) && (common_pid != 25407 && common_pid != 3750)"
  #

See you in the next cset!

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Brendan Gregg <brendan.d.gregg@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Luis Cláudio Gonçalves <lclaudio@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: https://lkml.kernel.org/n/tip-dx5j70fv2rgkeezd1cb3hv2p@git.kernel.orgSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

And also for 'struct strarray', since its needed to implement
strarrays__strtoul(). This just traverses the entries and when finding a
match, returns (offset + index), i.e. the value associated with the
searched string.

E.g. "EFER" (MSR_EFER) returns:

  # grep -w EFER -B2 /tmp/build/perf/trace/beauty/generated/x86_arch_MSRs_array.c
  #define x86_64_specific_MSRs_offset 0xc0000080
  static const char *x86_64_specific_MSRs[] = {
	[0xc0000080 - x86_64_specific_MSRs_offset] = "EFER",
  #

  0xc0000080

This will be auto-attached to 'struct syscall_arg_fmt' entries
associated with strarrays as soon as we add a ->strarray and ->strarrays
to 'struct syscall_arg_fmt'.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Brendan Gregg <brendan.d.gregg@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Luis Cláudio Gonçalves <lclaudio@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: https://lkml.kernel.org/n/tip-r2hpaahf8lishyb1owko9vs1@git.kernel.orgSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

This will go from a string to a number, so that filter expressions can
be constructed with strings and then, before applying the tracepoint
filters (or eBPF, in the future) we can map those strings to numbers.

The first one will be for 'msr' tracepoint arguments, but real quickly
we will be able to reuse all strarrays for that.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Brendan Gregg <brendan.d.gregg@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Luis Cláudio Gonçalves <lclaudio@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: https://lkml.kernel.org/n/tip-wgqq48agcgr95b8dmn6fygtr@git.kernel.orgSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

Similar to what is in 'perf record', works just like there:

  # perf trace -e msr:*
   328.297 :0/0 msr:write_msr(msr: FS_BASE, val: 140240388381888)
   328.302 :0/0 msr:write_msr(msr: FS_BASE, val: 140240388381888)
   328.306 :0/0 msr:write_msr(msr: FS_BASE, val: 140240388381888)
   328.317 :0/0 msr:write_msr(msr: FS_BASE, val: 140240388381888)
   328.322 :0/0 msr:write_msr(msr: FS_BASE, val: 140240388381888)
   328.327 :0/0 msr:write_msr(msr: FS_BASE, val: 140240388381888)
   328.331 :0/0 msr:write_msr(msr: FS_BASE, val: 140240388381888)
   328.336 :0/0 msr:write_msr(msr: FS_BASE, val: 140240388381888)
   328.340 :0/0 ^Cmsr:write_msr(msr: FS_BASE, val: 140240388381888)
  #

So, for a system wide trace session looking at the write_msr tracepoint
we see a flood of MSR_FS_BASE, we need to get the number for that:

  # grep FS_BASE /tmp/build/perf/trace/beauty/generated/x86_arch_MSRs_array.c
	[0xc0000100 - x86_64_specific_MSRs_offset] = "FS_BASE",
  #

And then use it in a filter:

  # perf trace -e msr:* --filter="msr!=0xc0000100"
  <SNIP>
   942.177 :0/0 msr:write_msr(msr: IA32_TSC_DEADLINE, val: 3056931068232)
   942.199 :0/0 msr:write_msr(msr: IA32_TSC_DEADLINE, val: 3057135655252)
   942.203 :0/0 msr:write_msr(msr: IA32_TSC_DEADLINE, val: 3056931068222)
   942.231 :0/0 msr:write_msr(msr: IA32_TSC_DEADLINE, val: 3056998373022)
   942.241 :0/0 msr:write_msr(msr: IA32_TSC_DEADLINE, val: 3056931068236)
  <SNIP>
  #

Ok, lets filter that too, too noisy:

  # grep TSC_DEADLINE /tmp/build/perf/trace/beauty/generated/x86_arch_MSRs_array.c
	[0x000006E0] = "IA32_TSC_DEADLINE",
  #

  # perf trace -e msr:* --filter="msr!=0xc0000100 && msr!=0x6e0" -a sleep 0.1
     0.000 :0/0 msr:read_msr(msr: IA32_TSC_ADJUST)
     0.066 CPU 0/KVM/4895 msr:write_msr(msr: IA32_SPEC_CTRL, val: 6)
     0.070 CPU 0/KVM/4895 msr:write_msr(msr: 0x830, val: 34359740667)
     0.099 CPU 0/KVM/4895 msr:read_msr(msr: IA32_SYSENTER_ESP, val: -2199021993472)
     0.100 CPU 0/KVM/4895 msr:read_msr(msr: IA32_APICBASE, val: 4276096000)
     0.101 CPU 0/KVM/4895 msr:read_msr(msr: IA32_DEBUGCTLMSR)
     0.109 :0/0 msr:write_msr(msr: IA32_SPEC_CTRL)
     1.000 :0/0 msr:write_msr(msr: 0x830, val: 17179871485)
    18.893 :0/0 msr:write_msr(msr: 0x83f, val: 246)
    28.810 :0/0 msr:write_msr(msr: 0x830, val: 68719479037)
    40.117 CPU 0/KVM/4895 msr:write_msr(msr: IA32_SPEC_CTRL, val: 6)
    40.127 CPU 0/KVM/4895 msr:read_msr(msr: IA32_DEBUGCTLMSR)
    40.139 CPU 0/KVM/4895 msr:write_msr(msr: LSTAR, val: -2130661312)
    40.141 CPU 0/KVM/4895 msr:write_msr(msr: SYSCALL_MASK, val: 14080)
    40.142 CPU 0/KVM/4895 msr:write_msr(msr: TSC_AUX)
    40.144 CPU 0/KVM/4895 msr:write_msr(msr: KERNEL_GS_BASE)
    40.147 CPU 0/KVM/4895 msr:write_msr(msr: IA32_SPEC_CTRL)
    40.148 CPU 0/KVM/4895 msr:write_msr(msr: IA32_FLUSH_CMD, val: 1)
    40.151 CPU 0/KVM/4895 msr:write_msr(msr: IA32_SPEC_CTRL, val: 6)
  ^C
  #

One can combine that with filtering pids as well:

  # perf trace -e msr:* --filter="msr!=0xc0000100 && msr!=0x6e0" --filter-pids 4895 -a sleep 0.09
     0.000 :0/0 msr:write_msr(msr: 0x830, val: 4294969597)
     0.291 gnome-terminal/2790 msr:write_msr(msr: SYSCALL_MASK, val: 292608)
     0.294 gnome-terminal/2790 msr:write_msr(msr: LSTAR, val: -1935671280)
     0.295 gnome-terminal/2790 msr:write_msr(msr: TSC_AUX, val: 6)
    10.940 gnome-terminal/2790 msr:write_msr(msr: 0x830, val: 4294969597)
    15.943 gnome-shell/2096 msr:write_msr(msr: 0x830, val: 4294969597)
    16.975 :0/0 msr:write_msr(msr: 0x830, val: 4294969597)
    19.560 :0/0 msr:write_msr(msr: 0x83f, val: 246)
    25.162 :0/0 msr:read_msr(msr: IA32_TSC_ADJUST)
    25.807 JS Watchdog/3635 msr:write_msr(msr: IA32_SPEC_CTRL, val: 6)
    25.820 :0/0 msr:write_msr(msr: IA32_SPEC_CTRL)
    25.941 gnome-terminal/2790 msr:write_msr(msr: 0x830, val: 4294969597)
    26.941 gnome-terminal/2790 msr:write_msr(msr: 0x830, val: 4294969597)
    29.942 gnome-terminal/2790 msr:write_msr(msr: 0x830, val: 4294969597)
    45.313 :0/0 msr:write_msr(msr: 0x83f, val: 246)
    56.945 gnome-terminal/2790 msr:write_msr(msr: 0x830, val: 4294969597)
    60.946 gnome-terminal/2790 msr:write_msr(msr: 0x830, val: 4294969597)
    74.096 JS Watchdog/8971 msr:write_msr(msr: IA32_SPEC_CTRL, val: 6)
    74.130 :0/0 msr:write_msr(msr: IA32_SPEC_CTRL)
    79.673 :0/0 msr:write_msr(msr: 0x83f, val: 246)
    79.947 gnome-terminal/2790 msr:write_msr(msr: 0x830, val: 17179871485)
  #

Or for just a pid, with callchains:

  # grep SYSCALL_MAS /tmp/build/perf/trace/beauty/generated/x86_arch_MSRs_array.c
	[0xc0000084 - x86_64_specific_MSRs_offset] = "SYSCALL_MASK",
  # perf trace -e msr:* --filter="msr==0xc0000084" --pid 2790 --call-graph=dwarf

     0.000 gnome-terminal/2790 msr:write_msr(msr: SYSCALL_MASK, val: 292608)
                                       do_trace_write_msr ([kernel.kallsyms])
                                       do_trace_write_msr ([kernel.kallsyms])
                                       kvm_on_user_return ([kvm])
                                       fire_user_return_notifiers ([kernel.kallsyms])
                                       exit_to_usermode_loop ([kernel.kallsyms])
                                       do_syscall_64 ([kernel.kallsyms])
                                       entry_SYSCALL_64 ([kernel.kallsyms])
                                       __GI___poll (inlined)
  9299.073 gnome-terminal/2790 msr:write_msr(msr: SYSCALL_MASK, val: 292608)
                                       do_trace_write_msr ([kernel.kallsyms])
                                       do_trace_write_msr ([kernel.kallsyms])
                                       kvm_on_user_return ([kvm])
                                       fire_user_return_notifiers ([kernel.kallsyms])
                                       exit_to_usermode_loop ([kernel.kallsyms])
                                       do_syscall_64 ([kernel.kallsyms])
                                       entry_SYSCALL_64 ([kernel.kallsyms])
                                       __GI___poll (inlined)
  9348.374 gnome-terminal/2790 msr:write_msr(msr: SYSCALL_MASK, val: 292608)
                                       do_trace_write_msr ([kernel.kallsyms])
                                       do_trace_write_msr ([kernel.kallsyms])
                                       kvm_on_user_return ([kvm])
                                       fire_user_return_notifiers ([kernel.kallsyms])
                                       exit_to_usermode_loop ([kernel.kallsyms])
                                       do_syscall_64 ([kernel.kallsyms])
                                       entry_SYSCALL_64 ([kernel.kallsyms])
                                       __GI___poll (inlined)
  <SNIP>
  #

Ok, just another form of KVM to emit MSRs :-)

Next step: elliminate those greps by getting the filter expression,
looking for arg names, then for the arrays associated with it to do a
reverse lookup.

Also allow those filters to be associated with strace-like syscall
names.

After that: augment the 'val' arg for 'msr:write_msr' based on the first
arg, 'msr'.

Then, do that with eBPF too, not just with tracepoint filters.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Brendan Gregg <brendan.d.gregg@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Luis Cláudio Gonçalves <lclaudio@redhat.com>
Cc: Marcelo Tosatti <mtosatti@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: https://lkml.kernel.org/n/tip-95bfe5d4tzy5f66bx49d05rj@git.kernel.orgSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

We'll need this to support 'perf trace e tracepoint --filter=expr', as
the command line tracepoint filter is attache to the preceding evsel,
just like in 'perf record' and when we go to set pid filters, which we
do at the minimum to filter 'perf trace' own syscalls, we need to
append, not set the tp filter.

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>
Link: https://lkml.kernel.org/n/tip-daynpknni44ywuzi8iua57nn@git.kernel.orgSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

Will be used by 'perf trace' to support 'perf trace --filter', we need
to append to any pre-existing filter.

When parse_filter() gets invoked to process --filter, it'll set the
filter to that specified on the command line, later on, when we filter
out 'perf trace' own pid to avoid an event feedback loop, we need to
preserve the command line filter put in place by parse_filter().

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>
Link: https://lkml.kernel.org/n/tip-h9rot08qmxlnfmte0holt68x@git.kernel.orgSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

Will be used to append such lists to existing filters.

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>
Link: https://lkml.kernel.org/n/tip-798vlyqfqw938ehoe8etivx1@git.kernel.orgSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

So that we can go from:

  # perf trace -e msr:write_msr --max-stack=16 sleep 1
       0.000 sleep/6740 msr:write_msr(msr: 3221225728, val: 139636317451648)
                                         do_trace_write_msr ([kernel.kallsyms])
                                         do_trace_write_msr ([kernel.kallsyms])
                                         do_arch_prctl_64 ([kernel.kallsyms])
                                         __x64_sys_arch_prctl ([kernel.kallsyms])
                                         do_syscall_64 ([kernel.kallsyms])
                                         entry_SYSCALL_64 ([kernel.kallsyms])
                                         init_tls (/usr/lib64/ld-2.29.so)
                                         dl_main (/usr/lib64/ld-2.29.so)
                                         _dl_sysdep_start (/usr/lib64/ld-2.29.so)
                                         _dl_start (/usr/lib64/ld-2.29.so)
  #

To:

  # perf trace -e msr:write_msr --max-stack=16 sleep 1
     0.000 sleep/8519 msr:write_msr(msr: FS_BASE, val: 139878031705472)
                                       do_trace_write_msr ([kernel.kallsyms])
                                       do_trace_write_msr ([kernel.kallsyms])
                                       do_arch_prctl_64 ([kernel.kallsyms])
                                       __x64_sys_arch_prctl ([kernel.kallsyms])
                                       do_syscall_64 ([kernel.kallsyms])
                                       entry_SYSCALL_64 ([kernel.kallsyms])
                                       init_tls (/usr/lib64/ld-2.29.so)
                                       dl_main (/usr/lib64/ld-2.29.so)
                                       _dl_sysdep_start (/usr/lib64/ld-2.29.so)
                                       _dl_start (/usr/lib64/ld-2.29.so)
  #

This, in reverse, will allow for symbolic system call/tracepoint
filtering.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Brendan Gregg <brendan.d.gregg@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Luis Cláudio Gonçalves <lclaudio@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: https://lkml.kernel.org/n/tip-q1q4unmqja5ex7dy0kb5cjaa@git.kernel.orgSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

We need to wrap those autogenerated string arrays with the
strarrays__scnprintf() formatter, do it.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Brendan Gregg <brendan.d.gregg@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Luis Cláudio Gonçalves <lclaudio@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: https://lkml.kernel.org/n/tip-wqjz4kwi4a0ot6lsis3kc65j@git.kernel.orgSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

For instance 'msr' appears in several tracepoints, so we can associate
it with a single scnprintf() routine auto-generated from kernel headers,
as will be done in followup patches.

Start with an empty array of associations.

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-89ptht6s5fez82lykuwq1eyb@git.kernel.orgSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

This way we generate the source with the table for later use by plugins,
etc.

I.e. after running:

  $ make -C tools/perf O=/tmp/build/perf

We end up with:

  $ head /tmp/build/perf/trace/beauty/generated/x86_arch_MSRs_array.c
  static const char *x86_MSRs[] = {
  	[0x00000000] = "IA32_P5_MC_ADDR",
  	[0x00000001] = "IA32_P5_MC_TYPE",
  	[0x00000010] = "IA32_TSC",
  	[0x00000017] = "IA32_PLATFORM_ID",
  	[0x0000001b] = "IA32_APICBASE",
  	[0x00000020] = "KNC_PERFCTR0",
  	[0x00000021] = "KNC_PERFCTR1",
  	[0x00000028] = "KNC_EVNTSEL0",
  	[0x00000029] = "KNC_EVNTSEL1",
  $

Now its just a matter of using it, first in a libtracevent plugin.

At some point we should move tools/perf/trace/beauty to tools/beauty/,
so that it can be used more generally and even made available externally
like libbpf, libperf, libtraevent, etc.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Brendan Gregg <brendan.d.gregg@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Luis Cláudio Gonçalves <lclaudio@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: https://lkml.kernel.org/n/tip-b3rmutg4igcohx6kpo67qh4j@git.kernel.orgSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

Without parameters it'll parse tools/arch/x86/include/asm/msr-index.h
and output a table usable by tools, that will be wired up later to a
libtraceevent plugin registered from perf's glue code:

  $ tools/perf/trace/beauty/tracepoints/x86_msr.sh
  static const char *x86_MSRs[] = {
 <SNIP>
  	[0x00000034] = "SMI_COUNT",
  	[0x0000003a] = "IA32_FEATURE_CONTROL",
  	[0x0000003b] = "IA32_TSC_ADJUST",
  	[0x00000040] = "LBR_CORE_FROM",
  	[0x00000048] = "IA32_SPEC_CTRL",
  	[0x00000049] = "IA32_PRED_CMD",
 <SNIP>
  	[0x0000010b] = "IA32_FLUSH_CMD",
  	[0x0000010F] = "TSX_FORCE_ABORT",
 <SNIP>
  	[0x00000198] = "IA32_PERF_STATUS",
  	[0x00000199] = "IA32_PERF_CTL",
  <SNIP>
  	[0x00000da0] = "IA32_XSS",
  	[0x00000dc0] = "LBR_INFO_0",
  	[0x00000ffc] = "IA32_BNDCFGS_RSVD",
  };

  #define x86_64_specific_MSRs_offset 0xc0000080
  static const char *x86_64_specific_MSRs[] = {
  	[0xc0000080 - x86_64_specific_MSRs_offset] = "EFER",
  	[0xc0000081 - x86_64_specific_MSRs_offset] = "STAR",
  	[0xc0000082 - x86_64_specific_MSRs_offset] = "LSTAR",
  	[0xc0000083 - x86_64_specific_MSRs_offset] = "CSTAR",
  	[0xc0000084 - x86_64_specific_MSRs_offset] = "SYSCALL_MASK",
  <SNIP>
  	[0xc0000103 - x86_64_specific_MSRs_offset] = "TSC_AUX",
  	[0xc0000104 - x86_64_specific_MSRs_offset] = "AMD64_TSC_RATIO",
  };

  #define x86_AMD_V_KVM_MSRs_offset 0xc0010000
  static const char *x86_AMD_V_KVM_MSRs[] = {
  	[0xc0010000 - x86_AMD_V_KVM_MSRs_offset] = "K7_EVNTSEL0",
  <SNIP>
  	[0xc0010114 - x86_AMD_V_KVM_MSRs_offset] = "VM_CR",
  	[0xc0010115 - x86_AMD_V_KVM_MSRs_offset] = "VM_IGNNE",
  	[0xc0010117 - x86_AMD_V_KVM_MSRs_offset] = "VM_HSAVE_PA",
  <SNIP>
  	[0xc0010240 - x86_AMD_V_KVM_MSRs_offset] = "F15H_NB_PERF_CTL",
  	[0xc0010241 - x86_AMD_V_KVM_MSRs_offset] = "F15H_NB_PERF_CTR",
  	[0xc0010280 - x86_AMD_V_KVM_MSRs_offset] = "F15H_PTSC",
  };

Then these will in turn be hooked up in a follow up patch to be used by
strarrays__scnprintf().

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Brendan Gregg <brendan.d.gregg@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Luis Cláudio Gonçalves <lclaudio@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: https://lkml.kernel.org/n/tip-ja080xawx08kedez855usnon@git.kernel.orgSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

We need it for things like MSRs that are sparse and go over MAXINT.

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>
Link: https://lkml.kernel.org/n/tip-g8t2d0jr0mg3yimg2qrjkvlt@git.kernel.orgSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

We'll use it to generate a table and then convert the
msr:{read,write}_msr 'msr' option in things like perf trace, script,
etc.

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-y1f4s0y1s43d4drh7pd2huzn@git.kernel.orgSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

So far we used the libtraceevent printing routines when showing
tracepoint arguments, but since 'perf trace' has a lot of beautifiers
for syscall arguments, and since some of those can be used to augment
tracepoint arguments, add a routine to make use of those beautifiers
and allow the user to choose which one to use.

The default now is to use the same beautifiers used for the strace-like
sys_enter+sys_exit lines, but the user can choose the libtraceevent ones
by either using the:

    perf trace --libtraceevent_print

command line option, or by setting:

  # cat ~/.perfconfig
  [trace]
	tracepoint_beautifiers = libtraceevent

For instance, here are some examples:

  # perf trace -e sched:*switch,*sleep,sched:*wakeup,exit*,sched:*exit sleep 1
       0.000 sched:sched_wakeup(comm: "perf", pid: 5273 (perf), prio: 120, success: 1, target_cpu: 6)
       0.621 nanosleep(rqtp: 0x7ffdd06d1140, rmtp: NULL) ...
       0.628 sched:sched_switch(prev_comm: "sleep", prev_pid: 5273 (sleep), prev_prio: 120, prev_state: 1, next_comm: "swapper/6", next_pid: 0, next_prio: 120)
    1000.879 sched:sched_wakeup(comm: "sleep", pid: 5273 (sleep), prio: 120, success: 1, target_cpu: 6)
       0.621  ... [continued]: nanosleep())          = 0
    1001.026 exit_group(error_code: 0)               = ?
    1001.216 sched:sched_process_exit(comm: "sleep", pid: 5273 (sleep), prio: 120)
  #

And then using libtraceevent, as before:

  # perf trace --libtraceevent_print -e sched:*switch,*sleep,sched:*wakeup,exit*,sched:*exit sleep 1
       0.000 sched:sched_wakeup(comm=perf pid=5288 prio=120 target_cpu=001)
       0.739 nanosleep(rqtp: 0x7ffeba6c2f40, rmtp: NULL) ...
       0.747 sched:sched_switch(prev_comm=sleep prev_pid=5288 prev_prio=120 prev_state=S ==> next_comm=swapper/1 next_pid=0 next_prio=120)
    1000.902 sched:sched_wakeup(comm=sleep pid=5288 prio=120 target_cpu=001)
       0.739  ... [continued]: nanosleep())          = 0
    1001.012 exit_group(error_code: 0)               = ?
  #

The new default allocates an array of 'struct syscall_arg_fmt' for the
tracepoint arguments and, just like with syscall arguments, tries to
find suitable syscall_arg__scnprintf_NAME() routines to augment those
tracepoint arguments based on their type (as in the tracefs "format"
file), or even in their name + type, for instance arguntents with names
ending in "fd" with type "int" get the fd scnprintf beautifier attached,
etc.

Soon this will take advantage of the kernel BTF information to augment
enumerations based on the tracefs "format" type info.

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>
Link: https://lkml.kernel.org/n/tip-o8qdluotkcb3b1x2gjqrejcl@git.kernel.orgSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

So that they look a bit like normal strace-like syscall enter+exit
lines.

They will look even more when we switch from using libtraceevent's
tep_print_event() routine in favour of using all the perf beautifiers
used by the strace-like syscall enter+exit lines.

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>
Link: https://lkml.kernel.org/n/tip-y4fcej6v6u1m644nbxd2r4pg@git.kernel.orgSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

Needed for sched's traceoints prev/next comm, where, unlike with
syscalls, we are not dealing with an integer or pointer, but an array
straight out from the ring buffer.

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>
Link: https://lkml.kernel.org/n/tip-rlll7tmcqe1g4odtaifil5re@git.kernel.orgSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

So that the scnprintf beautifiers can access it, as will be the case
with the char array one in the following csets, that needs to know
the number of elements in an array.

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>
Link: https://lkml.kernel.org/n/tip-01qmjqv6cb1nj1qy4khdexce@git.kernel.orgSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

Since all they operate on is on a syscall_arg_fmt instance, so move them
to allow use it from the upcoming tracepoint fprintf routine.

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>
Link: https://lkml.kernel.org/n/tip-ynttrs1l75f0x9tk67spd7jd@git.kernel.orgSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

This will work similar to the syscall args, we'll allocate an array
of 'struct syscall_arg_fmt' for the tracepoint args and then init them
using the same algorithm used for the defaults for syscall args, i.e.
using its types and sometimes names as hints to find the right scnprintf
routine to beautify them from numbers into strings.

Next step is to stop using libtracevent to printf tracepoints, as we'll
have more beautifiers than int provides, modulo perhaps some plugins.

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>
Link: https://lkml.kernel.org/n/tip-dcl135relxvf6ljisjg13aqg@git.kernel.orgSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

We set the default scnprint routines for the syscall args based on its
type or on heuristics based on its names, now we'll use this for
tracepoints as well, so move it out of syscall__set_arg_fmts() and into
a routine that receive just an array of syscall_arg_fmt entries + the
tracepoint format fields list.

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>
Link: https://lkml.kernel.org/n/tip-xs3x0zzyes06c7scdsjn01ty@git.kernel.orgSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

The original --reltime patch forbid --time with --reltime.

But it turns out --time doesn't really care about --reltime, because the
relative time is only used at final output, while the time filtering
always works earlier on absolute time.

So just remove the check and allow combining the two options.

Fixes: 90b10f47 ("perf script: Support relative time")
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Link: http://lore.kernel.org/lkml/20191002164642.1719-1-andi@firstfloor.orgSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

To remove that test_attr__{enabled/open} are used by perf-sys.h, we
set HAVE_ATTR_TEST to zero.
Signed-off-by: Björn Töpel <bjorn.topel@intel.com>
Tested-by: KP Singh <kpsingh@google.com>
Acked-by: Song Liu <songliubraving@fb.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: bpf@vger.kernel.org
Cc: netdev@vger.kernel.org
Link: http://lore.kernel.org/lkml/20191001113307.27796-3-bjorn.topel@gmail.comSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

For users of perf-sys.h outside perf, e.g. samples/bpf/bpf_load.c, it's
convenient not to depend on test_attr__*.

After commit 91854f9a ("perf tools: Move everything related to
sys_perf_event_open() to perf-sys.h"), all users of perf-sys.h will
depend on test_attr__enabled and test_attr__open.

This commit enables a user to define HAVE_ATTR_TEST to zero in order
to omit the test dependency.

Fixes: 91854f9a ("perf tools: Move everything related to sys_perf_event_open() to perf-sys.h")
Signed-off-by: Björn Töpel <bjorn.topel@intel.com>
Acked-by: Song Liu <songliubraving@fb.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: bpf@vger.kernel.org
Cc: netdev@vger.kernel.org
Link: http://lore.kernel.org/lkml/20191001113307.27796-2-bjorn.topel@gmail.comSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

Add a time chart based on context switch information.

Context switch information was added to the database export fairly
recently, so the chart menu option will only appear if context switch
information is in the database.

Refer to the Exported SQL Viewer Help option for more information about
the chart.
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Link: http://lore.kernel.org/lkml/20190821083216.1340-7-adrian.hunter@intel.comSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

perf scripts python: exported-sql-viewer.py: Add ability for Call tree to open at a specified task and time

Add ability for Call tree to open at a specified task and time.
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Link: http://lore.kernel.org/lkml/20190821083216.1340-6-adrian.hunter@intel.comSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

Record call_time on tree nodes and re-name the misnamed "count" parameter.
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Link: http://lore.kernel.org/lkml/20190821083216.1340-5-adrian.hunter@intel.comSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

Add calculations to determine a time range that encompasses all data.
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Link: http://lore.kernel.org/lkml/20190821083216.1340-4-adrian.hunter@intel.comSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

Add layout classes HBoxLayout and VBoxLayout.
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Link: http://lore.kernel.org/lkml/20190821083216.1340-3-adrian.hunter@intel.comSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

Add LookupModel() to find a model in the model cache without creating it.
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Link: http://lore.kernel.org/lkml/20190821083216.1340-2-adrian.hunter@intel.comSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

When not using augmented syscalls, i.e. not passing thru the command
line a eBPF source or object file event that provides the
__augmented_syscalls__ BPF_MAP_TYPE_PERF_EVENT_ARRAY, etc, as with:

   perf trace -e tools/perf/examples/bpf/augmented_raw_syscalls.c

or passing that augmented eBPF source/object via the trace.add_events in
.perfconfig file, we were assuming that syscalls were asked for,
differing from when not using augmented syscalls at all.

This is confusing when using .perfconfig to hide the fact we're using
the augmenter, i.e. using:

 # perf trace -e sched:* sleep 1

Will show both the scheduler tracepoints and the syscalls, where what we
want is to show just the scheduler tracepoints.

To see the scheduler tracepoints and some specific syscall strace-like
formatting, one has to use:

  # perf trace -e sched:*,nanosleep sleep 1

Or, if wanting all the syscalls:

  # perf trace -e sched:* --syscalls sleep 1

This way 'perf trace' can be used to trace just a set of tracepoints
while allowing for mixing with strace-like when desired, by simply
adding to the mix the name of the syscalls to show in addition to the
tracepoints.

Fix it so that the behaviour using the eBPF based syscall augmenter is
the same as when not using one.

Testing:

Before this patch, with this ~/.perfconfig:

  # egrep -B1 ^[[:space:]]+add_events ~/.perfconfig
  [trace]
  	add_events = /home/acme/git/perf/tools/perf/examples/bpf/augmented_raw_syscalls.o
  #

That points to this pre-compiled eBPF syscall augmenter:

  # file /home/acme/git/perf/tools/perf/examples/bpf/augmented_raw_syscalls.o
  /home/acme/git/perf/tools/perf/examples/bpf/augmented_raw_syscalls.o: ELF 64-bit LSB relocatable, eBPF, version 1 (SYSV), with debug_info, not stripped

And when asking for _only_ sched:sched_switch and sched:sched_wakeup we
were unconditionally getting all the syscalls formatted strace-like:

  # perf trace -e sched:*switch,sched:*wakeup sleep 1 |& tail
     0.633 fstat(3, 0x7fe11d030ac0)                = 0
     0.635 mmap(NULL, 217750512, PROT_READ, MAP_PRIVATE, 3, 0) = 0x7fe10fec5000
     0.643 close(3)                                = 0
     0.668 nanosleep(0x7fff649a3a90, NULL)      ...
     0.672 sched:sched_switch:prev_comm=sleep prev_pid=4417 prev_prio=120 prev_state=S ==> next_comm=swapper/6 next_pid=0 next_prio=120
  1000.822 sched:sched_wakeup:comm=sleep pid=4417 prio=120 target_cpu=006
     0.668  ... [continued]: nanosleep())          = 0
  1000.923 close(1)                                = 0
  1000.941 close(2)                                = 0
  1000.974 exit_group(0)                           = ?
  #

After the patch:

  # perf trace -e sched:*switch,sched:*wakeup sleep 1
     0.000 sched:sched_wakeup:comm=perf pid=5529 prio=120 target_cpu=005
     1.186 sched:sched_switch:prev_comm=sleep prev_pid=5529 prev_prio=120 prev_state=S ==> next_comm=swapper/5 next_pid=0 next_prio=120
  1001.573 sched:sched_wakeup:comm=sleep pid=5529 prio=120 target_cpu=005
  #

If we add the "open*" syscalls to the mix then the eBPF augmented _will_
be used and these syscalls will be traced together with the specified
sched tracepoints:

  # cd /sys/kernel/debug/tracing/events/syscalls/
  # ls -1d sys_enter_open*
  sys_enter_open
  sys_enter_openat
  sys_enter_open_by_handle_at
  sys_enter_open_tree
  #

  # perf trace -e open*,sched:*switch,sched:*wakeup sleep 1
       0.000 sched:sched_wakeup:comm=perf pid=5580 prio=120 target_cpu=005
       0.590 openat(AT_FDCWD, "/etc/ld.so.cache", O_RDONLY|O_CLOEXEC) = 3
       0.616 openat(AT_FDCWD, "/lib64/libc.so.6", O_RDONLY|O_CLOEXEC) = 3
       0.846 openat(AT_FDCWD, "/usr/lib/locale/locale-archive", O_RDONLY|O_CLOEXEC) = 3
       0.891 sched:sched_switch:prev_comm=sleep prev_pid=5580 prev_prio=120 prev_state=S ==> next_comm=swapper/5 next_pid=0 next_prio=120
    1001.005 sched:sched_wakeup:comm=sleep pid=5580 prio=120 target_cpu=005
  #

And as we can see, the pathnames were collected via the eBPF augmenters.

If we don't specify anything it'll trace all syscalls:

  # perf trace sleep 1 |& tail
       0.299 brk(0x5597543a3000)                     = 0x5597543a3000
       0.302 brk(NULL)                               = 0x5597543a3000
       0.307 openat(AT_FDCWD, "/usr/lib/locale/locale-archive", O_RDONLY|O_CLOEXEC) = 3
       0.313 fstat(3, 0x7feece50cac0)                = 0
       0.315 mmap(NULL, 217750512, PROT_READ, MAP_PRIVATE, 3, 0) = 0x7feec13a1000
       0.323 close(3)                                = 0
       0.354 nanosleep(0x7ffe338856e0, NULL)         = 0
    1000.641 close(1)                                = 0
    1000.655 close(2)                                = 0
    1000.673 exit_group(0)                           = ?
  #

Ditto if we don't use .perfconfig's trace.add_events but instead pass
just the augmenter as a command line event:

  # vim ~/.perfconfig
  # egrep -B1 ^[[:space:]]+add_events ~/.perfconfig
  # perf trace -e /home/acme/git/perf/tools/perf/examples/bpf/augmented_raw_syscalls.o sleep 1 |& tail
       0.294 brk(0x55ae08ec3000)                     = 0x55ae08ec3000
       0.297 brk(NULL)                               = 0x55ae08ec3000
       0.302 openat(AT_FDCWD, "/usr/lib/locale/locale-archive", O_RDONLY|O_CLOEXEC) = 3
       0.309 fstat(3, 0x7f726488fac0)                = 0
       0.311 mmap(NULL, 217750512, PROT_READ, MAP_PRIVATE, 3, 0) = 0x7f7257724000
       0.319 close(3)                                = 0
       0.347 nanosleep(0x7ffe23643a70, NULL)         = 0
    1000.560 close(1)                                = 0
    1000.575 close(2)                                = 0
    1000.593 exit_group(0)                           = ?
  #

As well as that + some syscall names for strace-like formatting:

  # perf trace -e socket,connect,/home/acme/git/perf/tools/perf/examples/bpf/augmented_raw_syscalls.o ssh localhost
       0.000 socket(PF_LOCAL, SOCK_STREAM|CLOEXEC|NONBLOCK, 0) = 3
       0.021 connect(3, { .family: PF_LOCAL, path: /var/run/nscd/socket }, 110) = -1 ENOENT (No such file or directory)
       0.034 socket(PF_LOCAL, SOCK_STREAM|CLOEXEC|NONBLOCK, 0) = 3
       0.041 connect(3, { .family: PF_LOCAL, path: /var/run/nscd/socket }, 110) = -1 ENOENT (No such file or directory)
       0.163 socket(PF_LOCAL, SOCK_STREAM, 0)        = 4
       0.185 connect(4, { .family: PF_LOCAL, path: /var/lib/sss/pipes/nss }, 110) = 0
       0.670 socket(PF_LOCAL, SOCK_STREAM|CLOEXEC|NONBLOCK, 0) = 7
       0.684 connect(7, { .family: PF_LOCAL, path: /var/run/nscd/socket }, 110) = -1 ENOENT (No such file or directory)
       0.694 socket(PF_LOCAL, SOCK_STREAM|CLOEXEC|NONBLOCK, 0) = 7
       0.701 connect(7, { .family: PF_LOCAL, path: /var/run/nscd/socket }, 110) = -1 ENOENT (No such file or directory)
       0.994 socket(PF_LOCAL, SOCK_STREAM|CLOEXEC|NONBLOCK, 0) = 5
       1.006 connect(5, { .family: PF_LOCAL, path: /var/run/nscd/socket }, 110) = -1 ENOENT (No such file or directory)
       1.014 socket(PF_LOCAL, SOCK_STREAM|CLOEXEC|NONBLOCK, 0) = 5
       1.022 connect(5, { .family: PF_LOCAL, path: /var/run/nscd/socket }, 110) = -1 ENOENT (No such file or directory)
       1.068 socket(PF_INET, SOCK_STREAM, IPPROTO_TCP) = 5
       1.087 connect(5, { .family: PF_INET, port: 22, addr: 127.0.0.1 }, 16) = 0
      24.299 socket(PF_LOCAL, SOCK_STREAM, 0)        = 6
      24.337 connect(6, { .family: PF_LOCAL, path: /var/run/.heim_org.h5l.kcm-socket }, 110) = 0
      28.441 socket(PF_LOCAL, SOCK_STREAM, 0)        = 6
      28.516 connect(6, { .family: PF_LOCAL, path: /var/run/.heim_org.h5l.kcm-socket }, 110) = 0
  root@localhost's password:^C
  #

Everything works without augmenters:

  # egrep -B1 ^[[:space:]]+add_events ~/.perfconfig
  # perf trace sleep 1 |& tail
       0.261 brk(0x5635068ac000)                     = 0x5635068ac000
       0.264 brk(NULL)                               = 0x5635068ac000
       0.268 openat(AT_FDCWD, 0xdce642a0, O_RDONLY|O_CLOEXEC) = 3
       0.275 fstat(3, 0x7f3fdce97ac0)                = 0
       0.277 mmap(NULL, 217750512, PROT_READ, MAP_PRIVATE, 3, 0) = 0x7f3fcfd2c000
       0.284 close(3)                                = 0
       0.310 nanosleep(0x7ffdaea6ecd0, NULL)         = 0
    1000.552 close(1)                                = 0
    1000.565 close(2)                                = 0
    1000.580 exit_group(0)                           = ?
  #

  # perf trace -e connect ssh localhost
       0.000 connect(3, 0x58266930, 110)             = -1 ENOENT (No such file or directory)
       0.022 connect(3, 0x58266af0, 110)             = -1 ENOENT (No such file or directory)
       0.150 connect(4, 0x58266b00, 110)             = 0
       0.490 connect(7, 0x58264150, 110)             = -1 ENOENT (No such file or directory)
       0.505 connect(7, 0x58264300, 110)             = -1 ENOENT (No such file or directory)
       0.832 connect(5, 0x58266220, 110)             = -1 ENOENT (No such file or directory)
       0.847 connect(5, 0x582663e0, 110)             = -1 ENOENT (No such file or directory)
       0.899 connect(5, 0x95ba0630, 16)              = 0
      25.619 connect(6, 0x58266360, 110)             = 0
      40.564 connect(6, 0x58266330, 110)             = 0
  root@localhost's password: ^C
  #

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Brendan Gregg <brendan.d.gregg@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Luis Cláudio Gonçalves <lclaudio@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: https://lkml.kernel.org/n/tip-624f6jxic04031tnt40va4dd@git.kernel.orgSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

When we add events via the '[trace]' section in perfconfig the command
line options are not yet processed, so when something goes wrong with
parsing those events and using --verbose is advised, we end up not
getting any more verbosity by doing so.

So just copy the trace.add_events string for later processing, after we
processed --verbose and the other command line options.

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>
Link: https://lkml.kernel.org/n/tip-d6wbnz85ftqljdll6ynjyjd8@git.kernel.orgSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

To allow them to be used with other stuff, such as tracepoints.

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>
Link: https://lkml.kernel.org/n/tip-od3gzg77ppqgnnrxqv40fvgx@git.kernel.orgSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

As this has all the things needed to format tracepoints events, not just
syscalls, that, after all, are just tracepoints with a set in stone ABI,
i.e. order and number of parameters.

For tracepoints we'll create a

  static struct syscall_fmt tracepoint_fmts[]

array and will fill the ->arg[] entries with the beautifier for each
positional argument and record the name, then, when we need it, we'll
just check that the position has the same name, maybe even type, so that
we can do some check that the tracepoint hasn't changed, if it has, we
can even reorder things.

Keep calling it syscall_fmt but use it as well for tracepoints, do it
this way to minimize changes and reuse what is in place for syscalls,
we'll see.

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>
Link: https://lkml.kernel.org/n/tip-2x1jgiev13zt4njaanlnne0d@git.kernel.orgSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

Renaming it to evlist__set_default_evsel_handler(), to better reflect
what we want to do, which is to set a default handler for events we
still haven't set a custom handler, like the ones for "msr:write_msr",
etc that are coming soon.

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-e1bit7upnpmtsayh8039kfuw@git.kernel.orgSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

It all operates on the evsels in the session's evlist, so move it to the
evlist layer to make it useful to tools not using perf_session, just
evlists, like 'perf trace' in live mode.

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-9oc53gnfi53vg82fvolkm85g@git.kernel.orgSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

Just read it so that later on the per arch init routine can use it,
e.g. x86__annotate_init().

When using a perf.data file this is obtained from a header that was put
there by 'perf record', and then it may be for another machine, another
arch.

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-4t4n3o8l8s0tc2b1pq53hyr4@git.kernel.orgSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

In 'perf top' we use that cpuid when initializing the per arch
annotation init routines (e.g. x86__annotate_init()) and in that case
(live mode, 'perf top') we need to obtain it from the running machine,
not from a perf.data file header.

Provide a means to do that. Will be used by 'perf top' in a followup
patch.

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-h2wb3sx7u7znx6lqfezrh7ca@git.kernel.orgSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>