perf test: Add Symbols test

Add a test to check function symbols do not overlap and are not zero
length.

The main motivation for the test is to make it easier to review changes
to PLT symbol synthesis i.e. changes to dso__synthesize_plt_symbols().

By default the test uses the perf executable as a test DSO, but a
specific DSO can be specified via a new perf test option "--dso".

The test is useful in the following ways:

- Any DSO can be tested, even ones that do not run on the current
architecture. For example, using cross-compiled DSOs to see how
well perf handles different architectures.

- With verbose > 1 (e.g. -vv), all the symbols are printed, which
makes it easier to see issues.

- perf removes duplicate symbols and expands zero-length symbols
to reach the next symbol, however that is done before adding
synthesized symbols, so the test is checking those also.

Example:

$ perf test -v Symbols
74: Symbols :
--- start ---
test child forked, pid 154918
Testing /home/user/bin/perf
Overlapping symbols:
7d000-7f3a0 g _init
7d030-7d040 g __printf_chk@plt
test child finished with -1
---- end ----
Symbols: FAILED!

Note the test fails because perf expands the _init symbol over the PLT
because there are no PLT symbols at that point, but then
dso__synthesize_plt_symbols() creates them.

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Acked-by: Ian Rogers <irogers@google.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: https://lore.kernel.org/r/20230120123456.12449-2-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

perf test: Add -F/--dont-fork option

Adding -F/--dont-fork option to bypass forking for each test. It's
useful for debugging test.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Tested-by: Nilay Vaish <nilayvaish@gmail.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1467113345-12669-1-git-send-email-jolsa@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

perf Documentation: Fix typos in perf/Documentation

This patch fix spelling typos found in tool/perf/Documentation.

Signed-off-by: Masanari Iida <standby24x7@gmail.com>
Acked-by: Randy Dunlap <rdunlap@infradead.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Randy Dunlap <rdunlap@infradead.org>
Link: http://lkml.kernel.org/r/1410275930-17207-1-git-send-email-standby24x7@gmail.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

perf test: Allow skipping tests

Sometimes a test is problematic for some reason and one wants to skip it,
for instance:

[root@sandy ~]# perf test
1: vmlinux symtab matches kallsyms : Ok
2: detect open syscall event : Ok
3: detect open syscall event on all cpus : Ok
4: read samples using the mmap interface : Ok
5: parse events tests : Warning: bad op token {
Warning: bad op token {
Warning: bad op token {
Warning: bad op token {
Warning: bad op token {
Warning: function is_writable_pte not defined
Segmentation fault (core dumped)

So now we can use -s/--skip while the problematic tests are being fixed,
allowing us to test all the other entries:

[root@sandy ~]# perf test -s 5
1: vmlinux symtab matches kallsyms : Ok
2: detect open syscall event : Ok
3: detect open syscall event on all cpus : Ok
4: read samples using the mmap interface : Ok
5: parse events tests : Skip (user override)
6: x86 rdpmc test : Ok
7: Validate PERF_RECORD_* events & perf_sample fields : Ok
8: Test perf pmu format parsing : Ok
9: Test dso data interface : Ok
10: roundtrip evsel->name check : Ok
11: Check parsing of sched tracepoints fields : Ok
12: Generate and check syscalls:sys_enter_open event fields: Ok
13: struct perf_event_attr setup : Ok
14: Test matching and linking mutliple hists : Ok
15: Try 'use perf' in python, checking link problems : Ok
[root@sandy ~]#

Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Namhyung Kim <namhyung@gmail.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/n/tip-klzd8p57jzdryafqkmlppcb1@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

perf test: Allow running just a subset of the available tests

To obtain a list of available tests:

[root@emilia linux]# perf test list
1: vmlinux symtab matches kallsyms
2: detect open syscall event
3: detect open syscall event on all cpus
4: read samples using the mmap interface
5: parse events tests
[root@emilia linux]#

To list just a subset:

[root@emilia linux]# perf test list syscall
2: detect open syscall event
3: detect open syscall event on all cpus
[root@emilia linux]#

To run a subset:

[root@emilia linux]# perf test detect
2: detect open syscall event: Ok
3: detect open syscall event on all cpus: Ok
[root@emilia linux]#

Specific tests can be chosen by number:

[root@emilia linux]# perf test 1 3 parse
1: vmlinux symtab matches kallsyms: Ok
3: detect open syscall event on all cpus: Ok
5: parse events tests: Ok
[root@emilia linux]#

Now to write more tests!

Suggested-by: Peter Zijlstra <peterz@infradead.org>
Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/n/tip-nqec2145qfxdgimux28aw7v8@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

perf test: Fix spelling mistake in documentation

Cc: Ingo Molnar <mingo@elte.hu>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <1291168642-11402-13-git-send-email-shawn.bohrer@gmail.com>
Signed-off-by: Shawn Bohrer <shawn.bohrer@gmail.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

perf test: Initial regression testing command

First an example with the first internal test:

[acme@doppio linux-2.6-tip]$ perf test
1: vmlinux symtab matches kallsyms: Ok

So it run just one test, that is "vmlinux symtab matches kallsyms", and it was
successful.

If we run it in verbose mode, we'll see details about errors and extra warnings
for non-fatal problems:

[acme@doppio linux-2.6-tip]$ perf test -v
1: vmlinux symtab matches kallsyms:
--- start ---
Looking at the vmlinux_path (5 entries long)
No build_id in vmlinux, ignoring it
No build_id in /boot/vmlinux, ignoring it
No build_id in /boot/vmlinux-2.6.34-rc4-tip+, ignoring it
Using /lib/modules/2.6.34-rc4-tip+/build/vmlinux for symbols
Maps only in vmlinux:
ffffffff81cb81b1-ffffffff81e1149b 0 [kernel].init.text
ffffffff81e1149c-ffffffff9fffffff 0 [kernel].exit.text
ffffffffff600000-ffffffffff6000ff 0 [kernel].vsyscall_0
ffffffffff600100-ffffffffff6003ff 0 [kernel].vsyscall_fn
ffffffffff600400-ffffffffff6007ff 0 [kernel].vsyscall_1
ffffffffff600800-ffffffffffffffff 0 [kernel].vsyscall_2
Maps in vmlinux with a different name in kallsyms:
ffffffffff600000-ffffffffff6000ff 0 [kernel].vsyscall_0 in kallsyms as [kernel].0
ffffffffff600100-ffffffffff6003ff 0 [kernel].vsyscall_fn in kallsyms as:
*ffffffffff600100-ffffffffff60012f 0 [kernel].2
ffffffffff600400-ffffffffff6007ff 0 [kernel].vsyscall_1 in kallsyms as [kernel].6
ffffffffff600800-ffffffffffffffff 0 [kernel].vsyscall_2 in kallsyms as [kernel].8
Maps only in kallsyms:
ffffffffff600130-ffffffffff6003ff 0 [kernel].4
---- end ----
vmlinux symtab matches kallsyms: Ok
[acme@doppio linux-2.6-tip]$

In the above case we only know the name of the non contiguous kernel ranges in
the address space when reading the symbol information from the ELF symtab in
vmlinux.

The /proc/kallsyms file lack this, we only notice they are separate because
there are modules after the kernel and after that more kernel functions, so we
need to have a module rbtree backed by the module .ko path to get symtabs in
the vmlinux case.

The tool uses it to match by address to emit appropriate warning, but don't
considers this fatal.

The .init.text and .exit.text ines, of course, aren't in kallsyms, so I left
these cases just as extra info in verbose mode.

The end of the sections also aren't in kallsyms, so we the symbols layer does
another pass and sets the end addresses as the next map start minus one, which
sometimes pads, causing harmless mismatches.

But at least the symbols match, tested it by copying /proc/kallsyms to
/tmp/kallsyms and doing changes to see if they were detected.

This first test also should serve as a first stab at documenting the
symbol library by providing a self contained example that exercises it
together with comments about what is being done.

More tests to check if actions done on a monitored app, like doing mmaps, etc,
makes the kernel generate the expected events should be added next.

Cc: Frédéric Weisbecker <fweisbec@gmail.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <new-submission>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>