perf trace: Augment 'newstat' (aka 'stat') filename ptr

This one will need some more work, that 'statbuf' pointer requires a
beautifier in 'perf trace'.

# perf trace -e tools/perf/examples/bpf/augmented_syscalls.c
0.000 weechat/3596 stat(filename: /etc/localtime, statbuf: 0x7ffd87d11f60)
0.186 perf/29818 openat(dfd: CWD, filename: /sys/kernel/debug/tracing/events/syscalls/sys_enter_stat/format)
0.279 perf/29818 openat(dfd: CWD, filename: /sys/kernel/debug/tracing/events/syscalls/sys_enter_newstat/for)
0.670 perf/29818 openat(dfd: CWD, filename: /sys/kernel/debug/tracing/events/syscalls/sys_enter_openat/form)
60.805 DNS Res~er #20/21308 stat(filename: /etc/resolv.conf, statbuf: 0x7ffa733fe4a0)
60.836 DNS Res~er #20/21308 open(filename: /etc/hosts, flags: CLOEXEC)
60.931 perf/29818 openat(dfd: CWD, filename: /sys/kernel/debug/tracing/events/syscalls/sys_enter_open/format)
607.070 DNS Res~er #21/29812 stat(filename: /etc/resolv.conf, statbuf: 0x7ffa5e1fe3f0)
607.098 DNS Res~er #21/29812 open(filename: /etc/hosts, flags: CLOEXEC)
999.336 weechat/3596 stat(filename: /etc/localtime, statbuf: 0x7ffd87d11f60)
^C#

Cc: Adrian Hunter <[e-mail]>
Cc: David Ahern <[e-mail]>
Cc: Jiri Olsa <[e-mail]>
Cc: Namhyung Kim <[e-mail]>
Cc: Wang Nan <[e-mail]>
Link: https://lkml.kernel.org/n/[e-mail]
Signed-off-by: Arnaldo Carvalho de Melo <[e-mail]>

tools/perf/examples/bpf/augmented_syscalls.c

···
 
 augmented_filename_syscall_enter(inotify_add_watch);
 
+struct statbuf;
+
+struct syscall_enter_newstat_args {
+	unsigned long long common_tp_fields;
+	long		   syscall_nr;
+	char		   *filename_ptr;
+	struct stat	   *statbuf;
+};
+
+augmented_filename_syscall_enter(newstat);
+
 license(GPL);