tracing/kprobes: Support basic types on dynamic events

Support basic types of integer (u8, u16, u32, u64, s8, s16, s32, s64) in
kprobe tracer. With this patch, users can specify above basic types on
each arguments after ':'. If omitted, the argument type is set as
unsigned long (u32 or u64, arch-dependent).

 e.g.
  echo 'p account_system_time+0 hardirq_offset=%si:s32' > kprobe_events

  adds a probe recording hardirq_offset in signed-32bits value on the
  entry of account_system_time.

Cc: Ingo Molnar <mingo@elte.hu>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
LKML-Reference: <20100412171708.3790.18599.stgit@localhost6.localdomain6>
Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

3 files changed, 334 insertions, 221 deletions

diff --git a/Documentation/trace/kprobetrace.txt b/Documentation/trace/kprobetrace.txt
index a9100b28eb84..ec94748ae65b 100644
--- a/Documentation/trace/kprobetrace.txt
+++ b/Documentation/trace/kprobetrace.txt
@@ -40,7 +40,9 @@ Synopsis of kprobe_events
   $stack        : Fetch stack address.
   $retval       : Fetch return value.(*)
   +|-offs(FETCHARG) : Fetch memory at FETCHARG +|- offs address.(**)
-  NAME=FETCHARG: Set NAME as the argument name of FETCHARG.
+  NAME=FETCHARG : Set NAME as the argument name of FETCHARG.
+  FETCHARG:TYPE : Set TYPE as the type of FETCHARG. Currently, basic types
+                  (u8/u16/u32/u64/s8/s16/s32/s64) are supported.
 
   (*) only for return probe.
   (**) this is useful for fetching a field of data structures.
diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index bec2c973ff0c..3ebdb6bd2362 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -102,29 +102,17 @@ struct syscall_trace_exit {
         long                    ret;
 };
 
-struct kprobe_trace_entry {
+struct kprobe_trace_entry_head {
         struct trace_entry      ent;
         unsigned long           ip;
-        int                     nargs;
-        unsigned long           args[];
 };
 
-#define SIZEOF_KPROBE_TRACE_ENTRY(n)                    \
-        (offsetof(struct kprobe_trace_entry, args) +    \
-        (sizeof(unsigned long) * (n)))
-
-struct kretprobe_trace_entry {
+struct kretprobe_trace_entry_head {
         struct trace_entry      ent;
         unsigned long           func;
         unsigned long           ret_ip;
-        int                     nargs;
-        unsigned long           args[];
 };
 
-#define SIZEOF_KRETPROBE_TRACE_ENTRY(n)                 \
-        (offsetof(struct kretprobe_trace_entry, args) + \
-        (sizeof(unsigned long) * (n)))
-
 /*
  * trace_flag_type is an enumeration that holds different
  * states when a trace occurs. These are:
diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c
index 1251e367bae9..a7514326052b 100644
--- a/kernel/trace/trace_kprobe.c
+++ b/kernel/trace/trace_kprobe.c
@@ -29,6 +29,8 @@
 #include <linux/ctype.h>
 #include <linux/ptrace.h>
 #include <linux/perf_event.h>
+#include <linux/stringify.h>
+#include <asm/bitsperlong.h>
 
 #include "trace.h"
 #include "trace_output.h"
@@ -40,7 +42,6 @@
 
 /* Reserved field names */
 #define FIELD_STRING_IP "__probe_ip"
-#define FIELD_STRING_NARGS "__probe_nargs"
 #define FIELD_STRING_RETIP "__probe_ret_ip"
 #define FIELD_STRING_FUNC "__probe_func"
 
@@ -52,56 +53,102 @@ const char *reserved_field_names[] = {
         "common_tgid",
         "common_lock_depth",
         FIELD_STRING_IP,
-        FIELD_STRING_NARGS,
         FIELD_STRING_RETIP,
         FIELD_STRING_FUNC,
 };
 
-struct fetch_func {
-        unsigned long (*func)(struct pt_regs *, void *);
+/* Printing function type */
+typedef int (*print_type_func_t)(struct trace_seq *, const char *, void *);
+#define PRINT_TYPE_FUNC_NAME(type)      print_type_##type
+#define PRINT_TYPE_FMT_NAME(type)       print_type_format_##type
+
+/* Printing  in basic type function template */
+#define DEFINE_BASIC_PRINT_TYPE_FUNC(type, fmt, cast)                   \
+static __kprobes int PRINT_TYPE_FUNC_NAME(type)(struct trace_seq *s,    \
+                                                const char *name, void *data)\
+{                                                                       \
+        return trace_seq_printf(s, " %s=" fmt, name, (cast)*(type *)data);\
+}                                                                       \
+static const char PRINT_TYPE_FMT_NAME(type)[] = fmt;
+
+DEFINE_BASIC_PRINT_TYPE_FUNC(u8, "%x", unsigned int)
+DEFINE_BASIC_PRINT_TYPE_FUNC(u16, "%x", unsigned int)
+DEFINE_BASIC_PRINT_TYPE_FUNC(u32, "%lx", unsigned long)
+DEFINE_BASIC_PRINT_TYPE_FUNC(u64, "%llx", unsigned long long)
+DEFINE_BASIC_PRINT_TYPE_FUNC(s8, "%d", int)
+DEFINE_BASIC_PRINT_TYPE_FUNC(s16, "%d", int)
+DEFINE_BASIC_PRINT_TYPE_FUNC(s32, "%ld", long)
+DEFINE_BASIC_PRINT_TYPE_FUNC(s64, "%lld", long long)
+
+/* Data fetch function type */
+typedef void (*fetch_func_t)(struct pt_regs *, void *, void *);
+
+struct fetch_param {
+        fetch_func_t    fn;
         void *data;
 };
 
-static __kprobes unsigned long call_fetch(struct fetch_func *f,
-                                          struct pt_regs *regs)
+static __kprobes void call_fetch(struct fetch_param *fprm,
+                                 struct pt_regs *regs, void *dest)
 {
-        return f->func(regs, f->data);
+        return fprm->fn(regs, fprm->data, dest);
 }
 
-/* fetch handlers */
-static __kprobes unsigned long fetch_register(struct pt_regs *regs,
-                                              void *offset)
-{
-        return regs_get_register(regs, (unsigned int)((unsigned long)offset));
+#define FETCH_FUNC_NAME(kind, type)     fetch_##kind##_##type
+/*
+ * Define macro for basic types - we don't need to define s* types, because
+ * we have to care only about bitwidth at recording time.
+ */
+#define DEFINE_BASIC_FETCH_FUNCS(kind)  \
+DEFINE_FETCH_##kind(u8)                 \
+DEFINE_FETCH_##kind(u16)                \
+DEFINE_FETCH_##kind(u32)                \
+DEFINE_FETCH_##kind(u64)
+
+#define CHECK_BASIC_FETCH_FUNCS(kind, fn)       \
+        ((FETCH_FUNC_NAME(kind, u8) == fn) ||   \
+         (FETCH_FUNC_NAME(kind, u16) == fn) ||  \
+         (FETCH_FUNC_NAME(kind, u32) == fn) ||  \
+         (FETCH_FUNC_NAME(kind, u64) == fn))
+
+/* Data fetch function templates */
+#define DEFINE_FETCH_reg(type)                                          \
+static __kprobes void FETCH_FUNC_NAME(reg, type)(struct pt_regs *regs,  \
+                                          void *offset, void *dest)     \
+{                                                                       \
+        *(type *)dest = (type)regs_get_register(regs,                   \
+                                (unsigned int)((unsigned long)offset)); \
 }
-
-static __kprobes unsigned long fetch_stack(struct pt_regs *regs,
-                                           void *num)
-{
-        return regs_get_kernel_stack_nth(regs,
-                                         (unsigned int)((unsigned long)num));
+DEFINE_BASIC_FETCH_FUNCS(reg)
+
+#define DEFINE_FETCH_stack(type)                                        \
+static __kprobes void FETCH_FUNC_NAME(stack, type)(struct pt_regs *regs,\
+                                          void *offset, void *dest)     \
+{                                                                       \
+        *(type *)dest = (type)regs_get_kernel_stack_nth(regs,           \
+                                (unsigned int)((unsigned long)offset)); \
 }
+DEFINE_BASIC_FETCH_FUNCS(stack)
 
-static __kprobes unsigned long fetch_memory(struct pt_regs *regs, void *addr)
-{
-        unsigned long retval;
-
-        if (probe_kernel_address(addr, retval))
-                return 0;
-        return retval;
+#define DEFINE_FETCH_retval(type)                                       \
+static __kprobes void FETCH_FUNC_NAME(retval, type)(struct pt_regs *regs,\
+                                          void *dummy, void *dest)      \
+{                                                                       \
+        *(type *)dest = (type)regs_return_value(regs);                  \
 }
-
-static __kprobes unsigned long fetch_retvalue(struct pt_regs *regs,
-                                              void *dummy)
-{
-        return regs_return_value(regs);
-}
-
-static __kprobes unsigned long fetch_stack_address(struct pt_regs *regs,
-                                                   void *dummy)
-{
-        return kernel_stack_pointer(regs);
+DEFINE_BASIC_FETCH_FUNCS(retval)
+
+#define DEFINE_FETCH_memory(type)                                       \
+static __kprobes void FETCH_FUNC_NAME(memory, type)(struct pt_regs *regs,\
+                                          void *addr, void *dest)       \
+{                                                                       \
+        type retval;                                                    \
+        if (probe_kernel_address(addr, retval))                         \
+                *(type *)dest = 0;                                      \
+        else                                                            \
+                *(type *)dest = retval;                                 \
 }
+DEFINE_BASIC_FETCH_FUNCS(memory)
 
 /* Memory fetching by symbol */
 struct symbol_cache {
@@ -145,51 +192,126 @@ static struct symbol_cache *alloc_symbol_cache(const char *sym, long offset)
         return sc;
 }
 
-static __kprobes unsigned long fetch_symbol(struct pt_regs *regs, void *data)
-{
-        struct symbol_cache *sc = data;
-
-        if (sc->addr)
-                return fetch_memory(regs, (void *)sc->addr);
-        else
-                return 0;
+#define DEFINE_FETCH_symbol(type)                                       \
+static __kprobes void FETCH_FUNC_NAME(symbol, type)(struct pt_regs *regs,\
+                                          void *data, void *dest)       \
+{                                                                       \
+        struct symbol_cache *sc = data;                                 \
+        if (sc->addr)                                                   \
+                fetch_memory_##type(regs, (void *)sc->addr, dest);      \
+        else                                                            \
+                *(type *)dest = 0;                                      \
 }
+DEFINE_BASIC_FETCH_FUNCS(symbol)
 
-/* Special indirect memory access interface */
-struct indirect_fetch_data {
-        struct fetch_func orig;
+/* Dereference memory access function */
+struct deref_fetch_param {
+        struct fetch_param orig;
         long offset;
 };
 
-static __kprobes unsigned long fetch_indirect(struct pt_regs *regs, void *data)
-{
-        struct indirect_fetch_data *ind = data;
-        unsigned long addr;
-
-        addr = call_fetch(&ind->orig, regs);
-        if (addr) {
-                addr += ind->offset;
-                return fetch_memory(regs, (void *)addr);
-        } else
-                return 0;
+#define DEFINE_FETCH_deref(type)                                        \
+static __kprobes void FETCH_FUNC_NAME(deref, type)(struct pt_regs *regs,\
+                                            void *data, void *dest)     \
+{                                                                       \
+        struct deref_fetch_param *dprm = data;                          \
+        unsigned long addr;                                             \
+        call_fetch(&dprm->orig, regs, &addr);                           \
+        if (addr) {                                                     \
+                addr += dprm->offset;                                   \
+                fetch_memory_##type(regs, (void *)addr, dest);          \
+        } else                                                          \
+                *(type *)dest = 0;                                      \
 }
+DEFINE_BASIC_FETCH_FUNCS(deref)
 
-static __kprobes void free_indirect_fetch_data(struct indirect_fetch_data *data)
+static __kprobes void free_deref_fetch_param(struct deref_fetch_param *data)
 {
-        if (data->orig.func == fetch_indirect)
-                free_indirect_fetch_data(data->orig.data);
-        else if (data->orig.func == fetch_symbol)
+        if (CHECK_BASIC_FETCH_FUNCS(deref, data->orig.fn))
+                free_deref_fetch_param(data->orig.data);
+        else if (CHECK_BASIC_FETCH_FUNCS(symbol, data->orig.fn))
                 free_symbol_cache(data->orig.data);
         kfree(data);
 }
 
+/* Default (unsigned long) fetch type */
+#define __DEFAULT_FETCH_TYPE(t) u##t
+#define _DEFAULT_FETCH_TYPE(t) __DEFAULT_FETCH_TYPE(t)
+#define DEFAULT_FETCH_TYPE _DEFAULT_FETCH_TYPE(BITS_PER_LONG)
+#define DEFAULT_FETCH_TYPE_STR __stringify(DEFAULT_FETCH_TYPE)
+
+#define ASSIGN_FETCH_FUNC(kind, type)   \
+        .kind = FETCH_FUNC_NAME(kind, type)
+
+#define ASSIGN_FETCH_TYPE(ptype, ftype, sign)   \
+        {.name = #ptype,                        \
+         .size = sizeof(ftype),                 \
+         .is_signed = sign,                     \
+         .print = PRINT_TYPE_FUNC_NAME(ptype),  \
+         .fmt = PRINT_TYPE_FMT_NAME(ptype),     \
+ASSIGN_FETCH_FUNC(reg, ftype),                  \
+ASSIGN_FETCH_FUNC(stack, ftype),                \
+ASSIGN_FETCH_FUNC(retval, ftype),               \
+ASSIGN_FETCH_FUNC(memory, ftype),               \
+ASSIGN_FETCH_FUNC(symbol, ftype),               \
+ASSIGN_FETCH_FUNC(deref, ftype),                \
+        }
+
+/* Fetch type information table */
+static const struct fetch_type {
+        const char      *name;          /* Name of type */
+        size_t          size;           /* Byte size of type */
+        int             is_signed;      /* Signed flag */
+        print_type_func_t       print;  /* Print functions */
+        const char      *fmt;           /* Fromat string */
+        /* Fetch functions */
+        fetch_func_t    reg;
+        fetch_func_t    stack;
+        fetch_func_t    retval;
+        fetch_func_t    memory;
+        fetch_func_t    symbol;
+        fetch_func_t    deref;
+} fetch_type_table[] = {
+        ASSIGN_FETCH_TYPE(u8,  u8,  0),
+        ASSIGN_FETCH_TYPE(u16, u16, 0),
+        ASSIGN_FETCH_TYPE(u32, u32, 0),
+        ASSIGN_FETCH_TYPE(u64, u64, 0),
+        ASSIGN_FETCH_TYPE(s8,  u8,  1),
+        ASSIGN_FETCH_TYPE(s16, u16, 1),
+        ASSIGN_FETCH_TYPE(s32, u32, 1),
+        ASSIGN_FETCH_TYPE(s64, u64, 1),
+};
+
+static const struct fetch_type *find_fetch_type(const char *type)
+{
+        int i;
+
+        if (!type)
+                type = DEFAULT_FETCH_TYPE_STR;
+
+        for (i = 0; i < ARRAY_SIZE(fetch_type_table); i++)
+                if (strcmp(type, fetch_type_table[i].name) == 0)
+                        return &fetch_type_table[i];
+        return NULL;
+}
+
+/* Special function : only accept unsigned long */
+static __kprobes void fetch_stack_address(struct pt_regs *regs,
+                                          void *dummy, void *dest)
+{
+        *(unsigned long *)dest = kernel_stack_pointer(regs);
+}
+
 /**
  * Kprobe event core functions
  */
 
 struct probe_arg {
-        struct fetch_func       fetch;
-        const char              *name;
+        struct fetch_param      fetch;
+        unsigned int            offset; /* Offset from argument entry */
+        const char              *name;  /* Name of this argument */
+        const char              *comm;  /* Command of this argument */
+        const struct fetch_type *type;  /* Type of this argument */
 };
 
 /* Flags for trace_probe */
@@ -204,6 +326,7 @@ struct trace_probe {
         const char              *symbol;        /* symbol name */
         struct ftrace_event_call        call;
         struct trace_event              event;
+        ssize_t                 size;           /* trace entry size */
         unsigned int            nr_args;
         struct probe_arg        args[];
 };
@@ -212,6 +335,7 @@ struct trace_probe {
         (offsetof(struct trace_probe, args) +   \
         (sizeof(struct probe_arg) * (n)))
 
+
 static __kprobes int probe_is_return(struct trace_probe *tp)
 {
         return tp->rp.handler != NULL;
@@ -222,49 +346,6 @@ static __kprobes const char *probe_symbol(struct trace_probe *tp)
         return tp->symbol ? tp->symbol : "unknown";
 }
 
-static int probe_arg_string(char *buf, size_t n, struct fetch_func *ff)
-{
-        int ret = -EINVAL;
-
-        if (ff->func == fetch_register) {
-                const char *name;
-                name = regs_query_register_name((unsigned int)((long)ff->data));
-                ret = snprintf(buf, n, "%%%s", name);
-        } else if (ff->func == fetch_stack)
-                ret = snprintf(buf, n, "$stack%lu", (unsigned long)ff->data);
-        else if (ff->func == fetch_memory)
-                ret = snprintf(buf, n, "@0x%p", ff->data);
-        else if (ff->func == fetch_symbol) {
-                struct symbol_cache *sc = ff->data;
-                if (sc->offset)
-                        ret = snprintf(buf, n, "@%s%+ld", sc->symbol,
-                                        sc->offset);
-                else
-                        ret = snprintf(buf, n, "@%s", sc->symbol);
-        } else if (ff->func == fetch_retvalue)
-                ret = snprintf(buf, n, "$retval");
-        else if (ff->func == fetch_stack_address)
-                ret = snprintf(buf, n, "$stack");
-        else if (ff->func == fetch_indirect) {
-                struct indirect_fetch_data *id = ff->data;
-                size_t l = 0;
-                ret = snprintf(buf, n, "%+ld(", id->offset);
-                if (ret >= n)
-                        goto end;
-                l += ret;
-                ret = probe_arg_string(buf + l, n - l, &id->orig);
-                if (ret < 0)
-                        goto end;
-                l += ret;
-                ret = snprintf(buf + l, n - l, ")");
-                ret += l;
-        }
-end:
-        if (ret >= n)
-                return -ENOSPC;
-        return ret;
-}
-
 static int register_probe_event(struct trace_probe *tp);
 static void unregister_probe_event(struct trace_probe *tp);
 
@@ -347,11 +428,12 @@ error:
 
 static void free_probe_arg(struct probe_arg *arg)
 {
-        if (arg->fetch.func == fetch_symbol)
+        if (CHECK_BASIC_FETCH_FUNCS(deref, arg->fetch.fn))
+                free_deref_fetch_param(arg->fetch.data);
+        else if (CHECK_BASIC_FETCH_FUNCS(symbol, arg->fetch.fn))
                 free_symbol_cache(arg->fetch.data);
-        else if (arg->fetch.func == fetch_indirect)
-                free_indirect_fetch_data(arg->fetch.data);
         kfree(arg->name);
+        kfree(arg->comm);
 }
 
 static void free_trace_probe(struct trace_probe *tp)
@@ -457,28 +539,30 @@ static int split_symbol_offset(char *symbol, unsigned long *offset)
 #define PARAM_MAX_ARGS 16
 #define PARAM_MAX_STACK (THREAD_SIZE / sizeof(unsigned long))
 
-static int parse_probe_vars(char *arg, struct fetch_func *ff, int is_return)
+static int parse_probe_vars(char *arg, const struct fetch_type *t,
+                            struct fetch_param *f, int is_return)
 {
         int ret = 0;
         unsigned long param;
 
         if (strcmp(arg, "retval") == 0) {
-                if (is_return) {
-                        ff->func = fetch_retvalue;
-                        ff->data = NULL;
-                } else
+                if (is_return)
+                        f->fn = t->retval;
+                else
                         ret = -EINVAL;
         } else if (strncmp(arg, "stack", 5) == 0) {
                 if (arg[5] == '\0') {
-                        ff->func = fetch_stack_address;
-                        ff->data = NULL;
+                        if (strcmp(t->name, DEFAULT_FETCH_TYPE_STR) == 0)
+                                f->fn = fetch_stack_address;
+                        else
+                                ret = -EINVAL;
                 } else if (isdigit(arg[5])) {
                         ret = strict_strtoul(arg + 5, 10, &param);
                         if (ret || param > PARAM_MAX_STACK)
                                 ret = -EINVAL;
                         else {
-                                ff->func = fetch_stack;
-                                ff->data = (void *)param;
+                                f->fn = t->stack;
+                                f->data = (void *)param;
                         }
                 } else
                         ret = -EINVAL;
@@ -488,7 +572,8 @@ static int parse_probe_vars(char *arg, struct fetch_func *ff, int is_return)
 }
 
 /* Recursive argument parser */
-static int __parse_probe_arg(char *arg, struct fetch_func *ff, int is_return)
+static int __parse_probe_arg(char *arg, const struct fetch_type *t,
+                             struct fetch_param *f, int is_return)
 {
         int ret = 0;
         unsigned long param;
@@ -497,13 +582,13 @@ static int __parse_probe_arg(char *arg, struct fetch_func *ff, int is_return)
 
         switch (arg[0]) {
         case '$':
-                ret = parse_probe_vars(arg + 1, ff, is_return);
+                ret = parse_probe_vars(arg + 1, t, f, is_return);
                 break;
         case '%':       /* named register */
                 ret = regs_query_register_offset(arg + 1);
                 if (ret >= 0) {
-                        ff->func = fetch_register;
-                        ff->data = (void *)(unsigned long)ret;
+                        f->fn = t->reg;
+                        f->data = (void *)(unsigned long)ret;
                         ret = 0;
                 }
                 break;
@@ -512,26 +597,22 @@ static int __parse_probe_arg(char *arg, struct fetch_func *ff, int is_return)
                         ret = strict_strtoul(arg + 1, 0, &param);
                         if (ret)
                                 break;
-                        ff->func = fetch_memory;
-                        ff->data = (void *)param;
+                        f->fn = t->memory;
+                        f->data = (void *)param;
                 } else {
                         ret = split_symbol_offset(arg + 1, &offset);
                         if (ret)
                                 break;
-                        ff->data = alloc_symbol_cache(arg + 1, offset);
-                        if (ff->data)
-                                ff->func = fetch_symbol;
-                        else
-                                ret = -EINVAL;
+                        f->data = alloc_symbol_cache(arg + 1, offset);
+                        if (f->data)
+                                f->fn = t->symbol;
                 }
                 break;
-        case '+':       /* indirect memory */
+        case '+':       /* deref memory */
         case '-':
                 tmp = strchr(arg, '(');
-                if (!tmp) {
-                        ret = -EINVAL;
+                if (!tmp)
                         break;
-                }
                 *tmp = '\0';
                 ret = strict_strtol(arg + 1, 0, &offset);
                 if (ret)
@@ -541,38 +622,58 @@ static int __parse_probe_arg(char *arg, struct fetch_func *ff, int is_return)
                 arg = tmp + 1;
                 tmp = strrchr(arg, ')');
                 if (tmp) {
-                        struct indirect_fetch_data *id;
+                        struct deref_fetch_param *dprm;
+                        const struct fetch_type *t2 = find_fetch_type(NULL);
                         *tmp = '\0';
-                        id = kzalloc(sizeof(struct indirect_fetch_data),
-                                     GFP_KERNEL);
-                        if (!id)
+                        dprm = kzalloc(sizeof(struct deref_fetch_param),
+                                       GFP_KERNEL);
+                        if (!dprm)
                                 return -ENOMEM;
-                        id->offset = offset;
-                        ret = __parse_probe_arg(arg, &id->orig, is_return);
+                        dprm->offset = offset;
+                        ret = __parse_probe_arg(arg, t2, &dprm->orig,
+                                                is_return);
                         if (ret)
-                                kfree(id);
+                                kfree(dprm);
                         else {
-                                ff->func = fetch_indirect;
-                                ff->data = (void *)id;
+                                f->fn = t->deref;
+                                f->data = (void *)dprm;
                         }
-                } else
-                        ret = -EINVAL;
+                }
                 break;
-        default:
-                /* TODO: support custom handler */
-                ret = -EINVAL;
         }
+        if (!ret && !f->fn)
+                ret = -EINVAL;
         return ret;
 }
 
 /* String length checking wrapper */
-static int parse_probe_arg(char *arg, struct fetch_func *ff, int is_return)
+static int parse_probe_arg(char *arg, struct trace_probe *tp,
+                           struct probe_arg *parg, int is_return)
 {
+        const char *t;
+
         if (strlen(arg) > MAX_ARGSTR_LEN) {
                 pr_info("Argument is too long.: %s\n",  arg);
                 return -ENOSPC;
         }
-        return __parse_probe_arg(arg, ff, is_return);
+        parg->comm = kstrdup(arg, GFP_KERNEL);
+        if (!parg->comm) {
+                pr_info("Failed to allocate memory for command '%s'.\n", arg);
+                return -ENOMEM;
+        }
+        t = strchr(parg->comm, ':');
+        if (t) {
+                arg[t - parg->comm] = '\0';
+                t++;
+        }
+        parg->type = find_fetch_type(t);
+        if (!parg->type) {
+                pr_info("Unsupported type: %s\n", t);
+                return -EINVAL;
+        }
+        parg->offset = tp->size;
+        tp->size += parg->type->size;
+        return __parse_probe_arg(arg, parg->type, &parg->fetch, is_return);
 }
 
 /* Return 1 if name is reserved or already used by another argument */
@@ -602,15 +703,18 @@ static int create_trace_probe(int argc, char **argv)
          *  @ADDR       : fetch memory at ADDR (ADDR should be in kernel)
          *  @SYM[+|-offs] : fetch memory at SYM +|- offs (SYM is a data symbol)
          *  %REG        : fetch register REG
-         * Indirect memory fetch:
+         * Dereferencing memory fetch:
          *  +|-offs(ARG) : fetch memory at ARG +|- offs address.
          * Alias name of args:
          *  NAME=FETCHARG : set NAME as alias of FETCHARG.
+         * Type of args:
+         *  FETCHARG:TYPE : use TYPE instead of unsigned long.
          */
         struct trace_probe *tp;
         int i, ret = 0;
         int is_return = 0, is_delete = 0;
-        char *symbol = NULL, *event = NULL, *arg = NULL, *group = NULL;
+        char *symbol = NULL, *event = NULL, *group = NULL;
+        char *arg, *tmp;
         unsigned long offset = 0;
         void *addr = NULL;
         char buf[MAX_EVENT_NAME_LEN];
@@ -723,13 +827,6 @@ static int create_trace_probe(int argc, char **argv)
                 else
                         arg = argv[i];
 
-                if (conflict_field_name(argv[i], tp->args, i)) {
-                        pr_info("Argument%d name '%s' conflicts with "
-                                "another field.\n", i, argv[i]);
-                        ret = -EINVAL;
-                        goto error;
-                }
-
                 tp->args[i].name = kstrdup(argv[i], GFP_KERNEL);
                 if (!tp->args[i].name) {
                         pr_info("Failed to allocate argument%d name '%s'.\n",
@@ -737,9 +834,19 @@ static int create_trace_probe(int argc, char **argv)
                         ret = -ENOMEM;
                         goto error;
                 }
+                tmp = strchr(tp->args[i].name, ':');
+                if (tmp)
+                        *tmp = '_';     /* convert : to _ */
+
+                if (conflict_field_name(tp->args[i].name, tp->args, i)) {
+                        pr_info("Argument%d name '%s' conflicts with "
+                                "another field.\n", i, argv[i]);
+                        ret = -EINVAL;
+                        goto error;
+                }
 
                 /* Parse fetch argument */
-                ret = parse_probe_arg(arg, &tp->args[i].fetch, is_return);
+                ret = parse_probe_arg(arg, tp, &tp->args[i], is_return);
                 if (ret) {
                         pr_info("Parse error at argument%d. (%d)\n", i, ret);
                         kfree(tp->args[i].name);
@@ -794,8 +901,7 @@ static void probes_seq_stop(struct seq_file *m, void *v)
 static int probes_seq_show(struct seq_file *m, void *v)
 {
         struct trace_probe *tp = v;
-        int i, ret;
-        char buf[MAX_ARGSTR_LEN + 1];
+        int i;
 
         seq_printf(m, "%c", probe_is_return(tp) ? 'r' : 'p');
         seq_printf(m, ":%s/%s", tp->call.system, tp->call.name);
@@ -807,15 +913,10 @@ static int probes_seq_show(struct seq_file *m, void *v)
         else
                 seq_printf(m, " %s", probe_symbol(tp));
 
-        for (i = 0; i < tp->nr_args; i++) {
-                ret = probe_arg_string(buf, MAX_ARGSTR_LEN, &tp->args[i].fetch);
-                if (ret < 0) {
-                        pr_warning("Argument%d decoding error(%d).\n", i, ret);
-                        return ret;
-                }
-                seq_printf(m, " %s=%s", tp->args[i].name, buf);
-        }
+        for (i = 0; i < tp->nr_args; i++)
+                seq_printf(m, " %s=%s", tp->args[i].name, tp->args[i].comm);
         seq_printf(m, "\n");
+
         return 0;
 }
 
@@ -945,9 +1046,10 @@ static const struct file_operations kprobe_profile_ops = {
 static __kprobes void kprobe_trace_func(struct kprobe *kp, struct pt_regs *regs)
 {
         struct trace_probe *tp = container_of(kp, struct trace_probe, rp.kp);
-        struct kprobe_trace_entry *entry;
+        struct kprobe_trace_entry_head *entry;
         struct ring_buffer_event *event;
         struct ring_buffer *buffer;
+        u8 *data;
         int size, i, pc;
         unsigned long irq_flags;
         struct ftrace_event_call *call = &tp->call;
@@ -957,7 +1059,7 @@ static __kprobes void kprobe_trace_func(struct kprobe *kp, struct pt_regs *regs)
         local_save_flags(irq_flags);
         pc = preempt_count();
 
-        size = SIZEOF_KPROBE_TRACE_ENTRY(tp->nr_args);
+        size = sizeof(*entry) + tp->size;
 
         event = trace_current_buffer_lock_reserve(&buffer, call->id, size,
                                                   irq_flags, pc);
@@ -965,10 +1067,10 @@ static __kprobes void kprobe_trace_func(struct kprobe *kp, struct pt_regs *regs)
                 return;
 
         entry = ring_buffer_event_data(event);
-        entry->nargs = tp->nr_args;
         entry->ip = (unsigned long)kp->addr;
+        data = (u8 *)&entry[1];
         for (i = 0; i < tp->nr_args; i++)
-                entry->args[i] = call_fetch(&tp->args[i].fetch, regs);
+                call_fetch(&tp->args[i].fetch, regs, data + tp->args[i].offset);
 
         if (!filter_current_check_discard(buffer, call, entry, event))
                 trace_nowake_buffer_unlock_commit(buffer, event, irq_flags, pc);
@@ -979,9 +1081,10 @@ static __kprobes void kretprobe_trace_func(struct kretprobe_instance *ri,
                                           struct pt_regs *regs)
 {
         struct trace_probe *tp = container_of(ri->rp, struct trace_probe, rp);
-        struct kretprobe_trace_entry *entry;
+        struct kretprobe_trace_entry_head *entry;
         struct ring_buffer_event *event;
         struct ring_buffer *buffer;
+        u8 *data;
         int size, i, pc;
         unsigned long irq_flags;
         struct ftrace_event_call *call = &tp->call;
@@ -989,7 +1092,7 @@ static __kprobes void kretprobe_trace_func(struct kretprobe_instance *ri,
         local_save_flags(irq_flags);
         pc = preempt_count();
 
-        size = SIZEOF_KRETPROBE_TRACE_ENTRY(tp->nr_args);
+        size = sizeof(*entry) + tp->size;
 
         event = trace_current_buffer_lock_reserve(&buffer, call->id, size,
                                                   irq_flags, pc);
@@ -997,11 +1100,11 @@ static __kprobes void kretprobe_trace_func(struct kretprobe_instance *ri,
                 return;
 
         entry = ring_buffer_event_data(event);
-        entry->nargs = tp->nr_args;
         entry->func = (unsigned long)tp->rp.kp.addr;
         entry->ret_ip = (unsigned long)ri->ret_addr;
+        data = (u8 *)&entry[1];
         for (i = 0; i < tp->nr_args; i++)
-                entry->args[i] = call_fetch(&tp->args[i].fetch, regs);
+                call_fetch(&tp->args[i].fetch, regs, data + tp->args[i].offset);
 
         if (!filter_current_check_discard(buffer, call, entry, event))
                 trace_nowake_buffer_unlock_commit(buffer, event, irq_flags, pc);
@@ -1011,13 +1114,14 @@ static __kprobes void kretprobe_trace_func(struct kretprobe_instance *ri,
 enum print_line_t
 print_kprobe_event(struct trace_iterator *iter, int flags)
 {
-        struct kprobe_trace_entry *field;
+        struct kprobe_trace_entry_head *field;
         struct trace_seq *s = &iter->seq;
         struct trace_event *event;
         struct trace_probe *tp;
+        u8 *data;
         int i;
 
-        field = (struct kprobe_trace_entry *)iter->ent;
+        field = (struct kprobe_trace_entry_head *)iter->ent;
         event = ftrace_find_event(field->ent.type);
         tp = container_of(event, struct trace_probe, event);
 
@@ -1030,9 +1134,10 @@ print_kprobe_event(struct trace_iterator *iter, int flags)
         if (!trace_seq_puts(s, ")"))
                 goto partial;
 
-        for (i = 0; i < field->nargs; i++)
-                if (!trace_seq_printf(s, " %s=%lx",
-                                      tp->args[i].name, field->args[i]))
+        data = (u8 *)&field[1];
+        for (i = 0; i < tp->nr_args; i++)
+                if (!tp->args[i].type->print(s, tp->args[i].name,
+                                             data + tp->args[i].offset))
                         goto partial;
 
         if (!trace_seq_puts(s, "\n"))
@@ -1046,13 +1151,14 @@ partial:
 enum print_line_t
 print_kretprobe_event(struct trace_iterator *iter, int flags)
 {
-        struct kretprobe_trace_entry *field;
+        struct kretprobe_trace_entry_head *field;
         struct trace_seq *s = &iter->seq;
         struct trace_event *event;
         struct trace_probe *tp;
+        u8 *data;
         int i;
 
-        field = (struct kretprobe_trace_entry *)iter->ent;
+        field = (struct kretprobe_trace_entry_head *)iter->ent;
         event = ftrace_find_event(field->ent.type);
         tp = container_of(event, struct trace_probe, event);
 
@@ -1071,9 +1177,10 @@ print_kretprobe_event(struct trace_iterator *iter, int flags)
         if (!trace_seq_puts(s, ")"))
                 goto partial;
 
-        for (i = 0; i < field->nargs; i++)
-                if (!trace_seq_printf(s, " %s=%lx",
-                                      tp->args[i].name, field->args[i]))
+        data = (u8 *)&field[1];
+        for (i = 0; i < tp->nr_args; i++)
+                if (!tp->args[i].type->print(s, tp->args[i].name,
+                                             data + tp->args[i].offset))
                         goto partial;
 
         if (!trace_seq_puts(s, "\n"))
@@ -1129,29 +1236,43 @@ static int probe_event_raw_init(struct ftrace_event_call *event_call)
 static int kprobe_event_define_fields(struct ftrace_event_call *event_call)
 {
         int ret, i;
-        struct kprobe_trace_entry field;
+        struct kprobe_trace_entry_head field;
         struct trace_probe *tp = (struct trace_probe *)event_call->data;
 
         DEFINE_FIELD(unsigned long, ip, FIELD_STRING_IP, 0);
-        DEFINE_FIELD(int, nargs, FIELD_STRING_NARGS, 1);
         /* Set argument names as fields */
-        for (i = 0; i < tp->nr_args; i++)
-                DEFINE_FIELD(unsigned long, args[i], tp->args[i].name, 0);
+        for (i = 0; i < tp->nr_args; i++) {
+                ret = trace_define_field(event_call, tp->args[i].type->name,
+                                         tp->args[i].name,
+                                         sizeof(field) + tp->args[i].offset,
+                                         tp->args[i].type->size,
+                                         tp->args[i].type->is_signed,
+                                         FILTER_OTHER);
+                if (ret)
+                        return ret;
+        }
         return 0;
 }
 
 static int kretprobe_event_define_fields(struct ftrace_event_call *event_call)
 {
         int ret, i;
-        struct kretprobe_trace_entry field;
+        struct kretprobe_trace_entry_head field;
         struct trace_probe *tp = (struct trace_probe *)event_call->data;
 
         DEFINE_FIELD(unsigned long, func, FIELD_STRING_FUNC, 0);
         DEFINE_FIELD(unsigned long, ret_ip, FIELD_STRING_RETIP, 0);
-        DEFINE_FIELD(int, nargs, FIELD_STRING_NARGS, 1);
         /* Set argument names as fields */
-        for (i = 0; i < tp->nr_args; i++)
-                DEFINE_FIELD(unsigned long, args[i], tp->args[i].name, 0);
+        for (i = 0; i < tp->nr_args; i++) {
+                ret = trace_define_field(event_call, tp->args[i].type->name,
+                                         tp->args[i].name,
+                                         sizeof(field) + tp->args[i].offset,
+                                         tp->args[i].type->size,
+                                         tp->args[i].type->is_signed,
+                                         FILTER_OTHER);
+                if (ret)
+                        return ret;
+        }
         return 0;
 }
 
@@ -1176,8 +1297,8 @@ static int __set_print_fmt(struct trace_probe *tp, char *buf, int len)
         pos += snprintf(buf + pos, LEN_OR_ZERO, "\"%s", fmt);
 
         for (i = 0; i < tp->nr_args; i++) {
-                pos += snprintf(buf + pos, LEN_OR_ZERO, " %s=%%lx",
-                                tp->args[i].name);
+                pos += snprintf(buf + pos, LEN_OR_ZERO, " %s=%s",
+                                tp->args[i].name, tp->args[i].type->fmt);
         }
 
         pos += snprintf(buf + pos, LEN_OR_ZERO, "\", %s", arg);
@@ -1219,12 +1340,13 @@ static __kprobes void kprobe_perf_func(struct kprobe *kp,
 {
         struct trace_probe *tp = container_of(kp, struct trace_probe, rp.kp);
         struct ftrace_event_call *call = &tp->call;
-        struct kprobe_trace_entry *entry;
+        struct kprobe_trace_entry_head *entry;
+        u8 *data;
         int size, __size, i;
         unsigned long irq_flags;
         int rctx;
 
-        __size = SIZEOF_KPROBE_TRACE_ENTRY(tp->nr_args);
+        __size = sizeof(*entry) + tp->size;
         size = ALIGN(__size + sizeof(u32), sizeof(u64));
         size -= sizeof(u32);
         if (WARN_ONCE(size > PERF_MAX_TRACE_SIZE,
@@ -1235,10 +1357,10 @@ static __kprobes void kprobe_perf_func(struct kprobe *kp,
         if (!entry)
                 return;
 
-        entry->nargs = tp->nr_args;
         entry->ip = (unsigned long)kp->addr;
+        data = (u8 *)&entry[1];
         for (i = 0; i < tp->nr_args; i++)
-                entry->args[i] = call_fetch(&tp->args[i].fetch, regs);
+                call_fetch(&tp->args[i].fetch, regs, data + tp->args[i].offset);
 
         perf_trace_buf_submit(entry, size, rctx, entry->ip, 1, irq_flags, regs);
 }
@@ -1249,12 +1371,13 @@ static __kprobes void kretprobe_perf_func(struct kretprobe_instance *ri,
 {
         struct trace_probe *tp = container_of(ri->rp, struct trace_probe, rp);
         struct ftrace_event_call *call = &tp->call;
-        struct kretprobe_trace_entry *entry;
+        struct kretprobe_trace_entry_head *entry;
+        u8 *data;
         int size, __size, i;
         unsigned long irq_flags;
         int rctx;
 
-        __size = SIZEOF_KRETPROBE_TRACE_ENTRY(tp->nr_args);
+        __size = sizeof(*entry) + tp->size;
         size = ALIGN(__size + sizeof(u32), sizeof(u64));
         size -= sizeof(u32);
         if (WARN_ONCE(size > PERF_MAX_TRACE_SIZE,
@@ -1265,11 +1388,11 @@ static __kprobes void kretprobe_perf_func(struct kretprobe_instance *ri,
         if (!entry)
                 return;
 
-        entry->nargs = tp->nr_args;
         entry->func = (unsigned long)tp->rp.kp.addr;
         entry->ret_ip = (unsigned long)ri->ret_addr;
+        data = (u8 *)&entry[1];
         for (i = 0; i < tp->nr_args; i++)
-                entry->args[i] = call_fetch(&tp->args[i].fetch, regs);
+                call_fetch(&tp->args[i].fetch, regs, data + tp->args[i].offset);
 
         perf_trace_buf_submit(entry, size, rctx, entry->ret_ip, 1,
                                irq_flags, regs);