perf trace: Group per syscall arg formatter info into one struct

Instead of having syscall_fmt.{arg_scnprintf,arg_parm}, introduce
struct syscall_arg_fmt and have these two, paving the way for more
state to change the formatting algorithms.

For instance, in the 'fcntl' 'cmd' case it is better not to suppress
it when being zero, showing instead its name "DUPFD".

We had that in an ad-hoc way just for strarrays, but with more involved
cases like fcntl, that can't be done with just a strarray, we'll need
a ".show_zero" arg in the 'cmd' syscall_arg_fmt.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/n/tip-ch06o2j72zbjx5xww4qp67au@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

diff --git a/tools/perf/builtin-trace.c b/tools/perf/builtin-trace.c
index 0dedce0ca0bbf323af53418d7ae55dd38f629fe1..32778a621a0826651b7607a0cac82310d32dc519 100644 (file)
--- a/tools/perf/builtin-trace.c
+++ b/tools/perf/builtin-trace.c
@@ -582,9 +582,9 @@ static size_t syscall_arg__scnprintf_getrandom_flags(char *bf, size_t size,
 
 #define SCA_GETRANDOM_FLAGS syscall_arg__scnprintf_getrandom_flags
 
-#define STRARRAY(arg, name, array) \
-         .arg_scnprintf = { [arg] = SCA_STRARRAY, }, \
-         .arg_parm      = { [arg] = &strarray__##array, }
+#define STRARRAY(name, array) \
+         { .scnprintf  = SCA_STRARRAY, \
+           .parm       = &strarray__##array, }
 
 #include "trace/beauty/eventfd.c"
 #include "trace/beauty/flock.c"
@@ -601,54 +601,61 @@ static size_t syscall_arg__scnprintf_getrandom_flags(char *bf, size_t size,
 #include "trace/beauty/socket_type.c"
 #include "trace/beauty/waitid_options.c"
 
+struct syscall_arg_fmt {
+       size_t     (*scnprintf)(char *bf, size_t size, struct syscall_arg *arg);
+       void       *parm;
+};
+
 static struct syscall_fmt {
        const char *name;
        const char *alias;
-       size_t     (*arg_scnprintf[6])(char *bf, size_t size, struct syscall_arg *arg);
-       void       *arg_parm[6];
+       struct syscall_arg_fmt arg[6];
        bool       errmsg;
        bool       errpid;
        bool       timeout;
        bool       hexret;
 } syscall_fmts[] = {
        { .name     = "access",     .errmsg = true,
-         .arg_scnprintf = { [1] = SCA_ACCMODE,  /* mode */ }, },
+         .arg = { [1] = { .scnprintf = SCA_ACCMODE,  /* mode */ }, }, },
        { .name     = "arch_prctl", .errmsg = true, .alias = "prctl", },
-       { .name     = "bpf",        .errmsg = true, STRARRAY(0, cmd, bpf_cmd), },
+       { .name     = "bpf",        .errmsg = true,
+         .arg = { [0] = STRARRAY(cmd, bpf_cmd), }, },
        { .name     = "brk",        .hexret = true,
-         .arg_scnprintf = { [0] = SCA_HEX, /* brk */ }, },
+         .arg = { [0] = { .scnprintf = SCA_HEX, /* brk */ }, }, },
        { .name     = "chdir",      .errmsg = true, },
        { .name     = "chmod",      .errmsg = true, },
        { .name     = "chroot",     .errmsg = true, },
-       { .name     = "clock_gettime",  .errmsg = true, STRARRAY(0, clk_id, clockid), },
+       { .name     = "clock_gettime", .errmsg = true,
+         .arg = { [0] = STRARRAY(clk_id, clockid), }, },
        { .name     = "clone",      .errpid = true, },
        { .name     = "close",      .errmsg = true,
-         .arg_scnprintf = { [0] = SCA_CLOSE_FD, /* fd */ }, },
+         .arg = { [0] = { .scnprintf = SCA_CLOSE_FD, /* fd */ }, }, },
        { .name     = "connect",    .errmsg = true, },
        { .name     = "creat",      .errmsg = true, },
        { .name     = "dup",        .errmsg = true, },
        { .name     = "dup2",       .errmsg = true, },
        { .name     = "dup3",       .errmsg = true, },
-       { .name     = "epoll_ctl",  .errmsg = true, STRARRAY(1, op, epoll_ctl_ops), },
+       { .name     = "epoll_ctl",  .errmsg = true,
+         .arg = { [1] = STRARRAY(op, epoll_ctl_ops), }, },
        { .name     = "eventfd2",   .errmsg = true,
-         .arg_scnprintf = { [1] = SCA_EFD_FLAGS, /* flags */ }, },
+         .arg = { [1] = { .scnprintf = SCA_EFD_FLAGS, /* flags */ }, }, },
        { .name     = "faccessat",  .errmsg = true, },
        { .name     = "fadvise64",  .errmsg = true, },
        { .name     = "fallocate",  .errmsg = true, },
        { .name     = "fchdir",     .errmsg = true, },
        { .name     = "fchmod",     .errmsg = true, },
        { .name     = "fchmodat",   .errmsg = true,
-         .arg_scnprintf = { [0] = SCA_FDAT, /* fd */ }, },
+         .arg = { [0] = { .scnprintf = SCA_FDAT, /* fd */ }, }, },
        { .name     = "fchown",     .errmsg = true, },
        { .name     = "fchownat",   .errmsg = true,
-         .arg_scnprintf = { [0] = SCA_FDAT, /* fd */ }, },
+         .arg = { [0] = { .scnprintf = SCA_FDAT, /* fd */ }, }, },
        { .name     = "fcntl",      .errmsg = true,
-         .arg_scnprintf = { [1] = SCA_FCNTL_CMD, /* cmd */
-                            [2] = SCA_FCNTL_ARG, /* arg */ },
-         .arg_parm      = { [1] = &strarrays__fcntl_cmds_arrays, /* cmd */ }, },
+         .arg = { [1] = { .scnprintf = SCA_FCNTL_CMD, /* cmd */
+                          .parm      = &strarrays__fcntl_cmds_arrays, /* cmd */ },
+                  [2] = { .scnprintf =  SCA_FCNTL_ARG, /* arg */ }, }, },
        { .name     = "fdatasync",  .errmsg = true, },
        { .name     = "flock",      .errmsg = true,
-         .arg_scnprintf = { [1] = SCA_FLOCK, /* cmd */ }, },
+         .arg = { [1] = { .scnprintf = SCA_FLOCK, /* cmd */ }, }, },
        { .name     = "fsetxattr",  .errmsg = true, },
        { .name     = "fstat",      .errmsg = true, .alias = "newfstat", },
        { .name     = "fstatat",    .errmsg = true, .alias = "newfstatat", },
@@ -656,186 +663,190 @@ static struct syscall_fmt {
        { .name     = "fsync",    .errmsg = true, },
        { .name     = "ftruncate", .errmsg = true, },
        { .name     = "futex",      .errmsg = true,
-         .arg_scnprintf = { [1] = SCA_FUTEX_OP, /* op */ }, },
+         .arg = { [1] = { .scnprintf = SCA_FUTEX_OP, /* op */ }, }, },
        { .name     = "futimesat", .errmsg = true,
-         .arg_scnprintf = { [0] = SCA_FDAT, /* fd */ }, },
+         .arg = { [0] = { .scnprintf = SCA_FDAT, /* fd */ }, }, },
        { .name     = "getdents",   .errmsg = true, },
        { .name     = "getdents64", .errmsg = true, },
-       { .name     = "getitimer",  .errmsg = true, STRARRAY(0, which, itimers), },
+       { .name     = "getitimer",  .errmsg = true,
+         .arg = { [0] = STRARRAY(which, itimers), }, },
        { .name     = "getpid",     .errpid = true, },
        { .name     = "getpgid",    .errpid = true, },
        { .name     = "getppid",    .errpid = true, },
        { .name     = "getrandom",  .errmsg = true,
-         .arg_scnprintf = { [2] = SCA_GETRANDOM_FLAGS, /* flags */ }, },
-       { .name     = "getrlimit",  .errmsg = true, STRARRAY(0, resource, rlimit_resources), },
+         .arg = { [2] = { .scnprintf = SCA_GETRANDOM_FLAGS, /* flags */ }, }, },
+       { .name     = "getrlimit",  .errmsg = true,
+         .arg = { [0] = STRARRAY(resource, rlimit_resources), }, },
        { .name     = "getxattr",   .errmsg = true, },
-       { .name     = "inotify_add_watch",          .errmsg = true, },
+       { .name     = "inotify_add_watch", .errmsg = true, },
        { .name     = "ioctl",      .errmsg = true,
-         .arg_scnprintf = {
+         .arg = {
 #if defined(__i386__) || defined(__x86_64__)
 /*
  * FIXME: Make this available to all arches.
  */
-                            [1] = SCA_STRHEXARRAY, /* cmd */
-                            [2] = SCA_HEX, /* arg */ },
-         .arg_parm      = { [1] = &strarray__tioctls, /* cmd */ }, },
+                  [1] = { .scnprintf = SCA_STRHEXARRAY, /* cmd */
+                          .parm      = &strarray__tioctls, },
+                  [2] = { .scnprintf = SCA_HEX, /* arg */ }, }, },
 #else
-                            [2] = SCA_HEX, /* arg */ }, },
+                  [2] = { .scnprintf = SCA_HEX, /* arg */ }, }, },
 #endif
-       { .name     = "keyctl",     .errmsg = true, STRARRAY(0, option, keyctl_options), },
+       { .name     = "keyctl",     .errmsg = true,
+         .arg = { [0] = STRARRAY(option, keyctl_options), }, },
        { .name     = "kill",       .errmsg = true,
-         .arg_scnprintf = { [1] = SCA_SIGNUM, /* sig */ }, },
+         .arg = { [1] = { .scnprintf = SCA_SIGNUM, /* sig */ }, }, },
        { .name     = "lchown",    .errmsg = true, },
        { .name     = "lgetxattr",  .errmsg = true, },
        { .name     = "linkat",     .errmsg = true,
-         .arg_scnprintf = { [0] = SCA_FDAT, /* fd */ }, },
+         .arg = { [0] = { .scnprintf = SCA_FDAT, /* fd */ }, }, },
        { .name     = "listxattr",  .errmsg = true, },
        { .name     = "llistxattr", .errmsg = true, },
        { .name     = "lremovexattr",  .errmsg = true, },
        { .name     = "lseek",      .errmsg = true,
-         .arg_scnprintf = { [2] = SCA_STRARRAY, /* whence */ },
-         .arg_parm      = { [2] = &strarray__whences, /* whence */ }, },
+         .arg = { [2] = STRARRAY(whence, whences), }, },
        { .name     = "lsetxattr",  .errmsg = true, },
        { .name     = "lstat",      .errmsg = true, .alias = "newlstat", },
        { .name     = "lsxattr",    .errmsg = true, },
        { .name     = "madvise",    .errmsg = true,
-         .arg_scnprintf = { [0] = SCA_HEX,      /* start */
-                            [2] = SCA_MADV_BHV, /* behavior */ }, },
+         .arg = { [0] = { .scnprintf = SCA_HEX,      /* start */ },
+                  [2] = { .scnprintf = SCA_MADV_BHV, /* behavior */ }, }, },
        { .name     = "mkdir",    .errmsg = true, },
        { .name     = "mkdirat",    .errmsg = true,
-         .arg_scnprintf = { [0] = SCA_FDAT, /* fd */ }, },
+         .arg = { [0] = { .scnprintf = SCA_FDAT, /* fd */ }, }, },
        { .name     = "mknod",      .errmsg = true, },
        { .name     = "mknodat",    .errmsg = true,
-         .arg_scnprintf = { [0] = SCA_FDAT, /* fd */ }, },
+         .arg = { [0] = { .scnprintf = SCA_FDAT, /* fd */ }, }, },
        { .name     = "mlock",      .errmsg = true,
-         .arg_scnprintf = { [0] = SCA_HEX, /* addr */ }, },
+         .arg = { [0] = { .scnprintf = SCA_HEX, /* addr */ }, }, },
        { .name     = "mlockall",   .errmsg = true,
-         .arg_scnprintf = { [0] = SCA_HEX, /* addr */ }, },
+         .arg = { [0] = { .scnprintf = SCA_HEX, /* addr */ }, }, },
        { .name     = "mmap",       .hexret = true,
 /* The standard mmap maps to old_mmap on s390x */
 #if defined(__s390x__)
        .alias = "old_mmap",
 #endif
-         .arg_scnprintf = { [0] = SCA_HEX,       /* addr */
-                            [2] = SCA_MMAP_PROT, /* prot */
-                            [3] = SCA_MMAP_FLAGS, /* flags */ }, },
+         .arg = { [0] = { .scnprintf = SCA_HEX,        /* addr */ },
+                  [2] = { .scnprintf = SCA_MMAP_PROT,  /* prot */ },
+                  [3] = { .scnprintf = SCA_MMAP_FLAGS, /* flags */ }, }, },
        { .name     = "mprotect",   .errmsg = true,
-         .arg_scnprintf = { [0] = SCA_HEX, /* start */
-                            [2] = SCA_MMAP_PROT, /* prot */ }, },
+         .arg = { [0] = { .scnprintf = SCA_HEX,        /* start */ },
+                  [2] = { .scnprintf = SCA_MMAP_PROT,  /* prot */ }, }, },
        { .name     = "mq_unlink", .errmsg = true,
-         .arg_scnprintf = { [0] = SCA_FILENAME, /* u_name */ }, },
+         .arg = { [0] = { .scnprintf = SCA_FILENAME, /* u_name */ }, }, },
        { .name     = "mremap",     .hexret = true,
-         .arg_scnprintf = { [0] = SCA_HEX, /* addr */
-                            [3] = SCA_MREMAP_FLAGS, /* flags */
-                            [4] = SCA_HEX, /* new_addr */ }, },
+         .arg = { [0] = { .scnprintf = SCA_HEX,          /* addr */ },
+                  [3] = { .scnprintf = SCA_MREMAP_FLAGS, /* flags */ },
+                  [4] = { .scnprintf = SCA_HEX,          /* new_addr */ }, }, },
        { .name     = "munlock",    .errmsg = true,
-         .arg_scnprintf = { [0] = SCA_HEX, /* addr */ }, },
+         .arg = { [0] = { .scnprintf = SCA_HEX, /* addr */ }, }, },
        { .name     = "munmap",     .errmsg = true,
-         .arg_scnprintf = { [0] = SCA_HEX, /* addr */ }, },
+         .arg = { [0] = { .scnprintf = SCA_HEX, /* addr */ }, }, },
        { .name     = "name_to_handle_at", .errmsg = true,
-         .arg_scnprintf = { [0] = SCA_FDAT, /* dfd */ }, },
+         .arg = { [0] = { .scnprintf = SCA_FDAT, /* dfd */ }, }, },
        { .name     = "newfstatat", .errmsg = true,
-         .arg_scnprintf = { [0] = SCA_FDAT, /* dfd */ }, },
+         .arg = { [0] = { .scnprintf = SCA_FDAT, /* dfd */ }, }, },
        { .name     = "open",       .errmsg = true,
-         .arg_scnprintf = { [1] = SCA_OPEN_FLAGS, /* flags */ }, },
+         .arg = { [1] = { .scnprintf = SCA_OPEN_FLAGS, /* flags */ }, }, },
        { .name     = "open_by_handle_at", .errmsg = true,
-         .arg_scnprintf = { [0] = SCA_FDAT, /* dfd */
-                            [2] = SCA_OPEN_FLAGS, /* flags */ }, },
+         .arg = { [0] = { .scnprintf = SCA_FDAT,       /* dfd */ },
+                  [2] = { .scnprintf = SCA_OPEN_FLAGS, /* flags */ }, }, },
        { .name     = "openat",     .errmsg = true,
-         .arg_scnprintf = { [0] = SCA_FDAT, /* dfd */
-                            [2] = SCA_OPEN_FLAGS, /* flags */ }, },
+         .arg = { [0] = { .scnprintf = SCA_FDAT,       /* dfd */ },
+                  [2] = { .scnprintf = SCA_OPEN_FLAGS, /* flags */ }, }, },
        { .name     = "perf_event_open", .errmsg = true,
-         .arg_scnprintf = { [2] = SCA_INT, /* cpu */
-                            [3] = SCA_FD,  /* group_fd */
-                            [4] = SCA_PERF_FLAGS,  /* flags */ }, },
+         .arg = { [2] = { .scnprintf = SCA_INT,        /* cpu */ },
+                  [3] = { .scnprintf = SCA_FD,         /* group_fd */ },
+                  [4] = { .scnprintf = SCA_PERF_FLAGS, /* flags */ }, }, },
        { .name     = "pipe2",      .errmsg = true,
-         .arg_scnprintf = { [1] = SCA_PIPE_FLAGS, /* flags */ }, },
+         .arg = { [1] = { .scnprintf = SCA_PIPE_FLAGS, /* flags */ }, }, },
        { .name     = "poll",       .errmsg = true, .timeout = true, },
        { .name     = "ppoll",      .errmsg = true, .timeout = true, },
        { .name     = "pread",      .errmsg = true, .alias = "pread64", },
        { .name     = "preadv",     .errmsg = true, .alias = "pread", },
-       { .name     = "prlimit64",  .errmsg = true, STRARRAY(1, resource, rlimit_resources), },
+       { .name     = "prlimit64",  .errmsg = true,
+         .arg = { [1] = STRARRAY(resource, rlimit_resources), }, },
        { .name     = "pwrite",     .errmsg = true, .alias = "pwrite64", },
        { .name     = "pwritev",    .errmsg = true, },
        { .name     = "read",       .errmsg = true, },
        { .name     = "readlink",   .errmsg = true, },
        { .name     = "readlinkat", .errmsg = true,
-         .arg_scnprintf = { [0] = SCA_FDAT, /* dfd */ }, },
+         .arg = { [0] = { .scnprintf = SCA_FDAT, /* dfd */ }, }, },
        { .name     = "readv",      .errmsg = true, },
        { .name     = "recvfrom",   .errmsg = true,
-         .arg_scnprintf = { [3] = SCA_MSG_FLAGS, /* flags */ }, },
+         .arg = { [3] = { .scnprintf = SCA_MSG_FLAGS, /* flags */ }, }, },
        { .name     = "recvmmsg",   .errmsg = true,
-         .arg_scnprintf = { [3] = SCA_MSG_FLAGS, /* flags */ }, },
+         .arg = { [3] = { .scnprintf = SCA_MSG_FLAGS, /* flags */ }, }, },
        { .name     = "recvmsg",    .errmsg = true,
-         .arg_scnprintf = { [2] = SCA_MSG_FLAGS, /* flags */ }, },
+         .arg = { [2] = { .scnprintf = SCA_MSG_FLAGS, /* flags */ }, }, },
        { .name     = "removexattr", .errmsg = true, },
        { .name     = "renameat",   .errmsg = true,
-         .arg_scnprintf = { [0] = SCA_FDAT, /* dfd */ }, },
+         .arg = { [0] = { .scnprintf = SCA_FDAT, /* dfd */ }, }, },
        { .name     = "rmdir",    .errmsg = true, },
        { .name     = "rt_sigaction", .errmsg = true,
-         .arg_scnprintf = { [0] = SCA_SIGNUM, /* sig */ }, },
-       { .name     = "rt_sigprocmask",  .errmsg = true, STRARRAY(0, how, sighow), },
+         .arg = { [0] = { .scnprintf = SCA_SIGNUM, /* sig */ }, }, },
+       { .name     = "rt_sigprocmask",  .errmsg = true,
+         .arg = { [0] = STRARRAY(how, sighow), }, },
        { .name     = "rt_sigqueueinfo", .errmsg = true,
-         .arg_scnprintf = { [1] = SCA_SIGNUM, /* sig */ }, },
+         .arg = { [1] = { .scnprintf = SCA_SIGNUM, /* sig */ }, }, },
        { .name     = "rt_tgsigqueueinfo", .errmsg = true,
-         .arg_scnprintf = { [2] = SCA_SIGNUM, /* sig */ }, },
+         .arg = { [2] = { .scnprintf = SCA_SIGNUM, /* sig */ }, }, },
        { .name     = "sched_getattr",        .errmsg = true, },
        { .name     = "sched_setattr",        .errmsg = true, },
        { .name     = "sched_setscheduler",   .errmsg = true,
-         .arg_scnprintf = { [1] = SCA_SCHED_POLICY, /* policy */ }, },
+         .arg = { [1] = { .scnprintf = SCA_SCHED_POLICY, /* policy */ }, }, },
        { .name     = "seccomp", .errmsg = true,
-         .arg_scnprintf = { [0] = SCA_SECCOMP_OP, /* op */
-                            [1] = SCA_SECCOMP_FLAGS, /* flags */ }, },
+         .arg = { [0] = { .scnprintf = SCA_SECCOMP_OP,    /* op */ },
+                  [1] = { .scnprintf = SCA_SECCOMP_FLAGS, /* flags */ }, }, },
        { .name     = "select",     .errmsg = true, .timeout = true, },
        { .name     = "sendmmsg",    .errmsg = true,
-         .arg_scnprintf = { [3] = SCA_MSG_FLAGS, /* flags */ }, },
+         .arg = { [3] = { .scnprintf = SCA_MSG_FLAGS, /* flags */ }, }, },
        { .name     = "sendmsg",    .errmsg = true,
-         .arg_scnprintf = { [2] = SCA_MSG_FLAGS, /* flags */ }, },
+         .arg = { [2] = { .scnprintf = SCA_MSG_FLAGS, /* flags */ }, }, },
        { .name     = "sendto",     .errmsg = true,
-         .arg_scnprintf = { [3] = SCA_MSG_FLAGS, /* flags */ }, },
+         .arg = { [3] = { .scnprintf = SCA_MSG_FLAGS, /* flags */ }, }, },
        { .name     = "set_tid_address", .errpid = true, },
-       { .name     = "setitimer",  .errmsg = true, STRARRAY(0, which, itimers), },
+       { .name     = "setitimer",  .errmsg = true,
+         .arg = { [0] = STRARRAY(which, itimers), }, },
        { .name     = "setpgid",    .errmsg = true, },
-       { .name     = "setrlimit",  .errmsg = true, STRARRAY(0, resource, rlimit_resources), },
+       { .name     = "setrlimit",  .errmsg = true,
+         .arg = { [0] = STRARRAY(resource, rlimit_resources), }, },
        { .name     = "setxattr",   .errmsg = true, },
        { .name     = "shutdown",   .errmsg = true, },
        { .name     = "socket",     .errmsg = true,
-         .arg_scnprintf = { [0] = SCA_STRARRAY, /* family */
-                            [1] = SCA_SK_TYPE, /* type */ },
-         .arg_parm      = { [0] = &strarray__socket_families, /* family */ }, },
+         .arg = { [0] = STRARRAY(family, socket_families),
+                  [1] = { .scnprintf = SCA_SK_TYPE, /* type */ }, }, },
        { .name     = "socketpair", .errmsg = true,
-         .arg_scnprintf = { [0] = SCA_STRARRAY, /* family */
-                            [1] = SCA_SK_TYPE, /* type */ },
-         .arg_parm      = { [0] = &strarray__socket_families, /* family */ }, },
+         .arg = { [0] = STRARRAY(family, socket_families),
+                  [1] = { .scnprintf = SCA_SK_TYPE, /* type */ }, }, },
        { .name     = "stat",       .errmsg = true, .alias = "newstat", },
        { .name     = "statfs",     .errmsg = true, },
        { .name     = "statx",      .errmsg = true,
-         .arg_scnprintf = { [0] = SCA_FDAT, /* flags */
-                            [2] = SCA_STATX_FLAGS, /* flags */
-                            [3] = SCA_STATX_MASK, /* mask */ }, },
+         .arg = { [0] = { .scnprintf = SCA_FDAT,        /* fdat */ },
+                  [2] = { .scnprintf = SCA_STATX_FLAGS, /* flags */ } ,
+                  [3] = { .scnprintf = SCA_STATX_MASK,  /* mask */ }, }, },
        { .name     = "swapoff",    .errmsg = true,
-         .arg_scnprintf = { [0] = SCA_FILENAME, /* specialfile */ }, },
+         .arg = { [0] = { .scnprintf = SCA_FILENAME, /* specialfile */ }, }, },
        { .name     = "swapon",     .errmsg = true,
-         .arg_scnprintf = { [0] = SCA_FILENAME, /* specialfile */ }, },
+         .arg = { [0] = { .scnprintf = SCA_FILENAME, /* specialfile */ }, }, },
        { .name     = "symlinkat",  .errmsg = true,
-         .arg_scnprintf = { [0] = SCA_FDAT, /* dfd */ }, },
+         .arg = { [0] = { .scnprintf = SCA_FDAT, /* dfd */ }, }, },
        { .name     = "tgkill",     .errmsg = true,
-         .arg_scnprintf = { [2] = SCA_SIGNUM, /* sig */ }, },
+         .arg = { [2] = { .scnprintf = SCA_SIGNUM, /* sig */ }, }, },
        { .name     = "tkill",      .errmsg = true,
-         .arg_scnprintf = { [1] = SCA_SIGNUM, /* sig */ }, },
+         .arg = { [1] = { .scnprintf = SCA_SIGNUM, /* sig */ }, }, },
        { .name     = "truncate",   .errmsg = true, },
        { .name     = "uname",      .errmsg = true, .alias = "newuname", },
        { .name     = "unlinkat",   .errmsg = true,
-         .arg_scnprintf = { [0] = SCA_FDAT, /* dfd */ }, },
+         .arg = { [0] = { .scnprintf = SCA_FDAT, /* dfd */ }, }, },
        { .name     = "utime",  .errmsg = true, },
        { .name     = "utimensat",  .errmsg = true,
-         .arg_scnprintf = { [0] = SCA_FDAT, /* dirfd */ }, },
+         .arg = { [0] = { .scnprintf = SCA_FDAT, /* dirfd */ }, }, },
        { .name     = "utimes",  .errmsg = true, },
        { .name     = "vmsplice",  .errmsg = true, },
        { .name     = "wait4",      .errpid = true,
-         .arg_scnprintf = { [2] = SCA_WAITID_OPTIONS, /* options */ }, },
+         .arg = { [2] = { .scnprintf = SCA_WAITID_OPTIONS, /* options */ }, }, },
        { .name     = "waitid",     .errpid = true,
-         .arg_scnprintf = { [3] = SCA_WAITID_OPTIONS, /* options */ }, },
+         .arg = { [3] = { .scnprintf = SCA_WAITID_OPTIONS, /* options */ }, }, },
        { .name     = "write",      .errmsg = true, },
        { .name     = "writev",     .errmsg = true, },
 };
@@ -859,8 +870,7 @@ struct syscall {
        const char          *name;
        bool                is_exit;
        struct syscall_fmt  *fmt;
-       size_t              (**arg_scnprintf)(char *bf, size_t size, struct syscall_arg *arg);
-       void                **arg_parm;
+       struct syscall_arg_fmt *arg_fmt;
 };
 
 /*
@@ -1209,27 +1219,29 @@ static int syscall__set_arg_fmts(struct syscall *sc)
        struct format_field *field;
        int idx = 0, len;
 
-       sc->arg_scnprintf = calloc(sc->nr_args, sizeof(void *));
-       if (sc->arg_scnprintf == NULL)
+       sc->arg_fmt = calloc(sc->nr_args, sizeof(*sc->arg_fmt));
+       if (sc->arg_fmt == NULL)
                return -1;
 
-       if (sc->fmt)
-               sc->arg_parm = sc->fmt->arg_parm;
+       for (field = sc->args; field; field = field->next, ++idx) {
+               if (sc->fmt) {
+                       sc->arg_fmt[idx] = sc->fmt->arg[idx];
+
+                       if (sc->fmt->arg[idx].scnprintf)
+                               continue;
+               }
 
-       for (field = sc->args; field; field = field->next) {
-               if (sc->fmt && sc->fmt->arg_scnprintf[idx])
-                       sc->arg_scnprintf[idx] = sc->fmt->arg_scnprintf[idx];
-               else if (strcmp(field->type, "const char *") == 0 &&
+               if (strcmp(field->type, "const char *") == 0 &&
                         (strcmp(field->name, "filename") == 0 ||
                          strcmp(field->name, "path") == 0 ||
                          strcmp(field->name, "pathname") == 0))
-                       sc->arg_scnprintf[idx] = SCA_FILENAME;
+                       sc->arg_fmt[idx].scnprintf = SCA_FILENAME;
                else if (field->flags & FIELD_IS_POINTER)
-                       sc->arg_scnprintf[idx] = syscall_arg__scnprintf_hex;
+                       sc->arg_fmt[idx].scnprintf = syscall_arg__scnprintf_hex;
                else if (strcmp(field->type, "pid_t") == 0)
-                       sc->arg_scnprintf[idx] = SCA_PID;
+                       sc->arg_fmt[idx].scnprintf = SCA_PID;
                else if (strcmp(field->type, "umode_t") == 0)
-                       sc->arg_scnprintf[idx] = SCA_MODE_T;
+                       sc->arg_fmt[idx].scnprintf = SCA_MODE_T;
                else if ((strcmp(field->type, "int") == 0 ||
                          strcmp(field->type, "unsigned int") == 0 ||
                          strcmp(field->type, "long") == 0) &&
@@ -1242,9 +1254,8 @@ static int syscall__set_arg_fmts(struct syscall *sc)
                         * 23 unsigned int
                         * 7 unsigned long
                         */
-                       sc->arg_scnprintf[idx] = SCA_FD;
+                       sc->arg_fmt[idx].scnprintf = SCA_FD;
                }
-               ++idx;
        }
 
        return 0;
@@ -1416,20 +1427,19 @@ static size_t syscall__scnprintf_args(struct syscall *sc, char *bf, size_t size,
                         * strarray for it.
                         */
                        if (val == 0 &&
-                           !(sc->arg_scnprintf &&
-                             (sc->arg_scnprintf[arg.idx] == SCA_STRARRAY ||
-                              sc->arg_scnprintf[arg.idx] == SCA_STRARRAYS) &&
-                             sc->arg_parm[arg.idx]))
+                           !(sc->arg_fmt &&
+                             (sc->arg_fmt[arg.idx].scnprintf == SCA_STRARRAY ||
+                              sc->arg_fmt[arg.idx].scnprintf == SCA_STRARRAYS) &&
+                             sc->arg_fmt[arg.idx].parm))
                                continue;
 
                        printed += scnprintf(bf + printed, size - printed,
                                             "%s%s: ", printed ? ", " : "", field->name);
-                       if (sc->arg_scnprintf && sc->arg_scnprintf[arg.idx]) {
+                       if (sc->arg_fmt && sc->arg_fmt[arg.idx].scnprintf) {
                                arg.val = val;
-                               if (sc->arg_parm)
-                                       arg.parm = sc->arg_parm[arg.idx];
-                               printed += sc->arg_scnprintf[arg.idx](bf + printed,
-                                                                     size - printed, &arg);
+                               if (sc->arg_fmt[arg.idx].parm)
+                                       arg.parm = sc->arg_fmt[arg.idx].parm;
+                               printed += sc->arg_fmt[arg.idx].scnprintf(bf + printed, size - printed, &arg);
                        } else {
                                printed += scnprintf(bf + printed, size - printed,
                                                     "%ld", val);