perf trace: Pretty print getrandom() args

  # trace -e getrandom
  35622.560 ( 0.023 ms): systemd-udevd/631 getrandom(buf: 0x55621e3c18f0, count: 16, flags: NONBLOCK) = 16
  35622.585 ( 0.006 ms): systemd-udevd/631 getrandom(buf: 0x55621e3c18f0, count: 16, flags: NONBLOCK) = 16
  35622.594 ( 0.004 ms): systemd-udevd/631 getrandom(buf: 0x55621e3c18f0, count: 16, flags: NONBLOCK) = 16
  35627.395 ( 0.010 ms): libvirtd/1353 getrandom(buf: 0x7f7a1bfa35c0, count: 16, flags: NONBLOCK    ) = 16
  35630.940 ( 0.013 ms): fwupd/16120 getrandom(buf: 0x7f63243aa5c0, count: 16, flags: NONBLOCK      ) = 16
  35718.613 ( 0.015 ms): systemd-udevd/631 getrandom(buf: 0x55621e3c18f0, count: 16, flags: NONBLOCK) = 16
  35718.629 ( 0.005 ms): systemd-udevd/631 getrandom(buf: 0x55621e3c18f0, count: 16, flags: NONBLOCK) = 16
  35718.637 ( 0.004 ms): systemd-udevd/631 getrandom(buf: 0x55621e3c18f0, count: 16, flags: NONBLOCK) = 16
  35719.355 ( 0.010 ms): libvirtd/1353 getrandom(buf: 0x7f7a1bfa35c0, count: 16, flags: NONBLOCK    ) = 16
  35721.042 ( 0.030 ms): fwupd/16120 getrandom(buf: 0x7f63243aa5c0, count: 16, flags: NONBLOCK      ) = 16
  41090.830 ( 0.012 ms): systemd-udevd/631 getrandom(buf: 0x55621e3c18f0, count: 16, flags: NONBLOCK) = 16
  41090.845 ( 0.004 ms): systemd-udevd/631 getrandom(buf: 0x55621e3c18f0, count: 16, flags: NONBLOCK) = 16
  41090.851 ( 0.004 ms): systemd-udevd/631 getrandom(buf: 0x55621e3c18f0, count: 16, flags: NONBLOCK) = 16
  41091.750 ( 0.010 ms): libvirtd/1353 getrandom(buf: 0x7f7a1bfa35c0, count: 16, flags: NONBLOCK    ) = 16
  41091.823 ( 0.006 ms): fwupd/16120 getrandom(buf: 0x7f63243aa5c0, count: 16, flags: NONBLOCK      ) = 16
  41122.078 ( 0.053 ms): systemd-udevd/631 getrandom(buf: 0x55621e3c18f0, count: 16, flags: NONBLOCK) = 16
  41122.129 ( 0.009 ms): systemd-udevd/631 getrandom(buf: 0x55621e3c18f0, count: 16, flags: NONBLOCK) = 16
  41122.139 ( 0.004 ms): systemd-udevd/631 getrandom(buf: 0x55621e3c18f0, count: 16, flags: NONBLOCK) = 16
  41124.492 ( 0.007 ms): libvirtd/1353 getrandom(buf: 0x7f7a1bfa35c0, count: 16, flags: NONBLOCK    ) = 16
  41124.470 ( 0.013 ms): fwupd/16120 getrandom(buf: 0x7f63243aa5c0, count: 16, flags: NONBLOCK      ) = 16
  41590.832 ( 0.014 ms): chrome/5957 getrandom(buf: 0x7fabac7b15b0, count: 16, flags: NONBLOCK      ) = 16
  41590.884 ( 0.004 ms): chrome/5957 getrandom(buf: 0x7fabac7b15c0, count: 16, flags: NONBLOCK      ) = 16

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Milian Wolff <milian.wolff@kdab.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/n/tip-gca0n1p3aca3depey703ph2q@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/builtin-trace.c

@@ -44,6 +44,7 @@
 #include <linux/filter.h>
 #include <linux/audit.h>
 #include <sys/ptrace.h>
+#include <linux/random.h>
 
 /* For older distros: */
 #ifndef MAP_STACK
@@ -1045,6 +1046,29 @@ static size_t syscall_arg__scnprintf_seccomp_flags(char *bf, size_t size,
 
 #define SCA_SECCOMP_FLAGS syscall_arg__scnprintf_seccomp_flags
 
+static size_t syscall_arg__scnprintf_getrandom_flags(char *bf, size_t size,
+						   struct syscall_arg *arg)
+{
+	int printed = 0, flags = arg->val;
+
+#define	P_FLAG(n) \
+	if (flags & GRND_##n) { \
+		printed += scnprintf(bf + printed, size - printed, "%s%s", printed ? "|" : "", #n); \
+		flags &= ~GRND_##n; \
+	}
+
+	P_FLAG(RANDOM);
+	P_FLAG(NONBLOCK);
+#undef P_FLAG
+
+	if (flags)
+		printed += scnprintf(bf + printed, size - printed, "%s%#x", printed ? "|" : "", flags);
+
+	return printed;
+}
+
+#define SCA_GETRANDOM_FLAGS syscall_arg__scnprintf_getrandom_flags
+
 #define STRARRAY(arg, name, array) \
 	  .arg_scnprintf = { [arg] = SCA_STRARRAY, }, \
 	  .arg_parm	 = { [arg] = &strarray__##array, }
@@ -1137,6 +1161,8 @@ static struct syscall_fmt {
 	{ .name	    = "getdents64", .errmsg = true,
 	  .arg_scnprintf = { [0] = SCA_FD, /* fd */ }, },
 	{ .name	    = "getitimer",  .errmsg = true, STRARRAY(0, which, itimers), },
+	{ .name	    = "getrandom",  .errmsg = true,
+	  .arg_scnprintf = { [2] = SCA_GETRANDOM_FLAGS, /* flags */ }, },
 	{ .name	    = "getrlimit",  .errmsg = true, STRARRAY(0, resource, rlimit_resources), },
 	{ .name	    = "getxattr",    .errmsg = true,
 	  .arg_scnprintf = { [0] = SCA_FILENAME, /* pathname */ }, },