Replace {k,u}probe event argument fetching framework
with switch-case based. Currently that is implemented
with structures, macros and chain of function-pointers,
which is more complicated than necessary and may get
a performance penalty by retpoline.

This simplify that with an array of "fetch_insn" (opcode
and oprands), and make process_fetch_insn() just
interprets it. No function pointers are used.

Signed-off-by: Masami Hiramatsu <mhira...@kernel.org>
---
 kernel/trace/trace_kprobe.c |  313 ++++++++++++------------------
 kernel/trace/trace_probe.c  |  446 +++++++++++++++----------------------------
 kernel/trace/trace_probe.h  |  252 +++++++++++-------------
 kernel/trace/trace_uprobe.c |  149 ++++++++------
 4 files changed, 472 insertions(+), 688 deletions(-)

diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c
index 1fe29b7f4c32..1d0554c6bb34 100644
--- a/kernel/trace/trace_kprobe.c
+++ b/kernel/trace/trace_kprobe.c
@@ -97,184 +97,6 @@ static int kprobe_dispatcher(struct kprobe *kp, struct 
pt_regs *regs);
 static int kretprobe_dispatcher(struct kretprobe_instance *ri,
                                struct pt_regs *regs);
 
-/* Memory fetching by symbol */
-struct symbol_cache {
-       char            *symbol;
-       long            offset;
-       unsigned long   addr;
-};
-
-unsigned long update_symbol_cache(struct symbol_cache *sc)
-{
-       sc->addr = (unsigned long)kallsyms_lookup_name(sc->symbol);
-
-       if (sc->addr)
-               sc->addr += sc->offset;
-
-       return sc->addr;
-}
-
-void free_symbol_cache(struct symbol_cache *sc)
-{
-       kfree(sc->symbol);
-       kfree(sc);
-}
-
-struct symbol_cache *alloc_symbol_cache(const char *sym, long offset)
-{
-       struct symbol_cache *sc;
-
-       if (!sym || strlen(sym) == 0)
-               return NULL;
-
-       sc = kzalloc(sizeof(struct symbol_cache), GFP_KERNEL);
-       if (!sc)
-               return NULL;
-
-       sc->symbol = kstrdup(sym, GFP_KERNEL);
-       if (!sc->symbol) {
-               kfree(sc);
-               return NULL;
-       }
-       sc->offset = offset;
-       update_symbol_cache(sc);
-
-       return sc;
-}
-
-/*
- * Kprobes-specific fetch functions
- */
-#define DEFINE_FETCH_stack(type)                                       \
-static 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)); \
-}                                                                      \
-NOKPROBE_SYMBOL(FETCH_FUNC_NAME(stack, type));
-
-DEFINE_BASIC_FETCH_FUNCS(stack)
-/* No string on the stack entry */
-#define fetch_stack_string     NULL
-#define fetch_stack_string_size        NULL
-
-#define DEFINE_FETCH_memory(type)                                      \
-static 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;                                 \
-}                                                                      \
-NOKPROBE_SYMBOL(FETCH_FUNC_NAME(memory, type));
-
-DEFINE_BASIC_FETCH_FUNCS(memory)
-/*
- * Fetch a null-terminated string. Caller MUST set *(u32 *)dest with max
- * length and relative data location.
- */
-static void FETCH_FUNC_NAME(memory, string)(struct pt_regs *regs,
-                                           void *addr, void *dest)
-{
-       int maxlen = get_rloc_len(*(u32 *)dest);
-       u8 *dst = get_rloc_data(dest);
-       long ret;
-
-       if (!maxlen)
-               return;
-
-       /*
-        * Try to get string again, since the string can be changed while
-        * probing.
-        */
-       ret = strncpy_from_unsafe(dst, addr, maxlen);
-
-       if (ret < 0) {  /* Failed to fetch string */
-               dst[0] = '\0';
-               *(u32 *)dest = make_data_rloc(0, get_rloc_offs(*(u32 *)dest));
-       } else {
-               *(u32 *)dest = make_data_rloc(ret, get_rloc_offs(*(u32 *)dest));
-       }
-}
-NOKPROBE_SYMBOL(FETCH_FUNC_NAME(memory, string));
-
-/* Return the length of string -- including null terminal byte */
-static void FETCH_FUNC_NAME(memory, string_size)(struct pt_regs *regs,
-                                                void *addr, void *dest)
-{
-       mm_segment_t old_fs;
-       int ret, len = 0;
-       u8 c;
-
-       old_fs = get_fs();
-       set_fs(KERNEL_DS);
-       pagefault_disable();
-
-       do {
-               ret = __copy_from_user_inatomic(&c, (u8 *)addr + len, 1);
-               len++;
-       } while (c && ret == 0 && len < MAX_STRING_SIZE);
-
-       pagefault_enable();
-       set_fs(old_fs);
-
-       if (ret < 0)    /* Failed to check the length */
-               *(u32 *)dest = 0;
-       else
-               *(u32 *)dest = len;
-}
-NOKPROBE_SYMBOL(FETCH_FUNC_NAME(memory, string_size));
-
-#define DEFINE_FETCH_symbol(type)                                      \
-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;                                      \
-}                                                                      \
-NOKPROBE_SYMBOL(FETCH_FUNC_NAME(symbol, type));
-
-DEFINE_BASIC_FETCH_FUNCS(symbol)
-DEFINE_FETCH_symbol(string)
-DEFINE_FETCH_symbol(string_size)
-
-/* kprobes don't support file_offset fetch methods */
-#define fetch_file_offset_u8           NULL
-#define fetch_file_offset_u16          NULL
-#define fetch_file_offset_u32          NULL
-#define fetch_file_offset_u64          NULL
-#define fetch_file_offset_string       NULL
-#define fetch_file_offset_string_size  NULL
-
-/* Fetch type information table */
-static const struct fetch_type kprobes_fetch_type_table[] = {
-       /* Special types */
-       [FETCH_TYPE_STRING] = __ASSIGN_FETCH_TYPE("string", string, string,
-                                       sizeof(u32), 1, "__data_loc char[]"),
-       [FETCH_TYPE_STRSIZE] = __ASSIGN_FETCH_TYPE("string_size", u32,
-                                       string_size, sizeof(u32), 0, "u32"),
-       /* Basic types */
-       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),
-       ASSIGN_FETCH_TYPE_ALIAS(x8,  u8,  u8,  0),
-       ASSIGN_FETCH_TYPE_ALIAS(x16, u16, u16, 0),
-       ASSIGN_FETCH_TYPE_ALIAS(x32, u32, u32, 0),
-       ASSIGN_FETCH_TYPE_ALIAS(x64, u64, u64, 0),
-
-       ASSIGN_FETCH_TYPE_END
-};
-
 /*
  * Allocate new trace_probe and initialize it (including kprobes).
  */
@@ -458,14 +280,11 @@ disable_trace_kprobe(struct trace_kprobe *tk, struct 
trace_event_file *file)
 /* Internal register function - just handle k*probes and flags */
 static int __register_trace_kprobe(struct trace_kprobe *tk)
 {
-       int i, ret;
+       int ret;
 
        if (trace_probe_is_registered(&tk->tp))
                return -EINVAL;
 
-       for (i = 0; i < tk->tp.nr_args; i++)
-               traceprobe_update_arg(&tk->tp.args[i]);
-
        /* Set/clear disabled flag according to tp->flag */
        if (trace_probe_is_enabled(&tk->tp))
                tk->rp.kp.flags &= ~KPROBE_FLAG_DISABLED;
@@ -798,8 +617,7 @@ static int create_trace_kprobe(int argc, char **argv)
 
                /* Parse fetch argument */
                ret = traceprobe_parse_probe_arg(arg, &tk->tp.size, parg,
-                                               is_return, true,
-                                               kprobes_fetch_type_table);
+                                                is_return, true);
                if (ret) {
                        pr_info("Parse error at argument[%d]. (%d)\n", i, ret);
                        goto error;
@@ -953,6 +771,133 @@ static const struct file_operations kprobe_profile_ops = {
        .release        = seq_release,
 };
 
+/* Kprobe specific fetch functions */
+
+/* Return the length of string -- including null terminal byte */
+static nokprobe_inline void
+fetch_store_strlen(unsigned long addr, void *dest)
+{
+       mm_segment_t old_fs;
+       int ret, len = 0;
+       u8 c;
+
+       old_fs = get_fs();
+       set_fs(KERNEL_DS);
+       pagefault_disable();
+
+       do {
+               ret = __copy_from_user_inatomic(&c, (u8 *)addr + len, 1);
+               len++;
+       } while (c && ret == 0 && len < MAX_STRING_SIZE);
+
+       pagefault_enable();
+       set_fs(old_fs);
+
+       if (ret < 0)    /* Failed to check the length */
+               *(u32 *)dest = 0;
+       else
+               *(u32 *)dest = len;
+}
+
+/*
+ * Fetch a null-terminated string. Caller MUST set *(u32 *)buf with max
+ * length and relative data location.
+ */
+static nokprobe_inline void
+fetch_store_string(unsigned long addr, void *dest)
+{
+       int maxlen = get_rloc_len(*(u32 *)dest);
+       u8 *dst = get_rloc_data(dest);
+       long ret;
+
+       if (!maxlen)
+               return;
+
+       /*
+        * Try to get string again, since the string can be changed while
+        * probing.
+        */
+       ret = strncpy_from_unsafe(dst, (void *)addr, maxlen);
+
+       if (ret < 0) {  /* Failed to fetch string */
+               dst[0] = '\0';
+               *(u32 *)dest = make_data_rloc(0, get_rloc_offs(*(u32 *)dest));
+       } else {
+               *(u32 *)dest = make_data_rloc(ret, get_rloc_offs(*(u32 *)dest));
+       }
+}
+
+/* Note that we don't verify it, since the code does not come from user space 
*/
+static int
+process_fetch_insn(struct fetch_insn *code, struct pt_regs *regs, void *dest,
+                  bool pre)
+{
+       unsigned long val;
+       int ret;
+
+       /* 1st stage: get value from context */
+       switch (code->op) {
+       case FETCH_OP_REG:
+               val = regs_get_register(regs, code->param);
+               break;
+       case FETCH_OP_STACK:
+               val = regs_get_kernel_stack_nth(regs, code->param);
+               break;
+       case FETCH_OP_STACKP:
+               val = kernel_stack_pointer(regs);
+               break;
+       case FETCH_OP_RETVAL:
+               val = regs_return_value(regs);
+               break;
+       case FETCH_OP_IMM:
+               val = code->immediate;
+               break;
+       case FETCH_OP_COMM:
+               val = (unsigned long)current->comm;
+               break;
+       default:
+               return -EILSEQ;
+       }
+       code++;
+
+       /* 2nd stage: dereference memory if needed */
+       while (code->op == FETCH_OP_DEREF) {
+               ret = probe_kernel_read(&val, (void *)val + code->offset,
+                                       sizeof(val));
+               if (ret)
+                       return ret;
+               code++;
+       }
+
+       /* 3rd stage: store value to buffer */
+       switch (code->op) {
+       case FETCH_OP_ST_RAW:
+               fetch_store_raw(val, code, dest);
+               break;
+       case FETCH_OP_ST_MEM:
+               probe_kernel_read(dest, (void *)val + code->offset, code->size);
+               break;
+       case FETCH_OP_ST_STRING:
+               if (pre)
+                       fetch_store_strlen(val + code->offset, dest);
+               else
+                       fetch_store_string(val + code->offset, dest);
+               break;
+       default:
+               return -EILSEQ;
+       }
+       code++;
+
+       /* 4th stage: modify stored value if needed */
+       if (code->op == FETCH_OP_MOD_BF) {
+               fetch_apply_bitfield(code, dest);
+               code++;
+       }
+
+       return code->op == FETCH_OP_END ? 0 : -EILSEQ;
+}
+NOKPROBE_SYMBOL(process_fetch_insn)
+
 /* Kprobe handler */
 static nokprobe_inline void
 __kprobe_trace_func(struct trace_kprobe *tk, struct pt_regs *regs,
diff --git a/kernel/trace/trace_probe.c b/kernel/trace/trace_probe.c
index be98a58416a9..52b4931864d6 100644
--- a/kernel/trace/trace_probe.c
+++ b/kernel/trace/trace_probe.c
@@ -73,176 +73,41 @@ int PRINT_TYPE_FUNC_NAME(string)(struct trace_seq *s, void 
*data, void *ent)
 
 const char PRINT_TYPE_FMT_NAME(string)[] = "\\\"%s\\\"";
 
-#define CHECK_FETCH_FUNCS(method, fn)                  \
-       (((FETCH_FUNC_NAME(method, u8) == fn) ||        \
-         (FETCH_FUNC_NAME(method, u16) == fn) ||       \
-         (FETCH_FUNC_NAME(method, u32) == fn) ||       \
-         (FETCH_FUNC_NAME(method, u64) == fn) ||       \
-         (FETCH_FUNC_NAME(method, string) == fn) ||    \
-         (FETCH_FUNC_NAME(method, string_size) == fn)) \
-        && (fn != NULL))
-
-/* Data fetch function templates */
-#define DEFINE_FETCH_reg(type)                                         \
-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)); \
-}                                                                      \
-NOKPROBE_SYMBOL(FETCH_FUNC_NAME(reg, type));
-DEFINE_BASIC_FETCH_FUNCS(reg)
-/* No string on the register */
-#define fetch_reg_string       NULL
-#define fetch_reg_string_size  NULL
-
-#define DEFINE_FETCH_retval(type)                                      \
-void FETCH_FUNC_NAME(retval, type)(struct pt_regs *regs,               \
-                                  void *dummy, void *dest)             \
-{                                                                      \
-       *(type *)dest = (type)regs_return_value(regs);                  \
-}                                                                      \
-NOKPROBE_SYMBOL(FETCH_FUNC_NAME(retval, type));
-DEFINE_BASIC_FETCH_FUNCS(retval)
-/* No string on the retval */
-#define fetch_retval_string            NULL
-#define fetch_retval_string_size       NULL
-
-/* Dereference memory access function */
-struct deref_fetch_param {
-       struct fetch_param      orig;
-       long                    offset;
-       fetch_func_t            fetch;
-       fetch_func_t            fetch_size;
-};
-
-#define DEFINE_FETCH_deref(type)                                       \
-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;                                   \
-               dprm->fetch(regs, (void *)addr, dest);                  \
-       } else                                                          \
-               *(type *)dest = 0;                                      \
-}                                                                      \
-NOKPROBE_SYMBOL(FETCH_FUNC_NAME(deref, type));
-DEFINE_BASIC_FETCH_FUNCS(deref)
-DEFINE_FETCH_deref(string)
-
-void FETCH_FUNC_NAME(deref, string_size)(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 && dprm->fetch_size) {
-               addr += dprm->offset;
-               dprm->fetch_size(regs, (void *)addr, dest);
-       } else
-               *(string_size *)dest = 0;
-}
-NOKPROBE_SYMBOL(FETCH_FUNC_NAME(deref, string_size));
-
-static void update_deref_fetch_param(struct deref_fetch_param *data)
-{
-       if (CHECK_FETCH_FUNCS(deref, data->orig.fn))
-               update_deref_fetch_param(data->orig.data);
-       else if (CHECK_FETCH_FUNCS(symbol, data->orig.fn))
-               update_symbol_cache(data->orig.data);
-}
-NOKPROBE_SYMBOL(update_deref_fetch_param);
+/*
+ * Kprobes-specific fetch functions
+ */
 
-static void free_deref_fetch_param(struct deref_fetch_param *data)
+/* dummy template */
+static int
+process_fetch_insn(struct fetch_insn *code, struct pt_regs *regs,
+                  void *dest, bool pre)
 {
-       if (CHECK_FETCH_FUNCS(deref, data->orig.fn))
-               free_deref_fetch_param(data->orig.data);
-       else if (CHECK_FETCH_FUNCS(symbol, data->orig.fn))
-               free_symbol_cache(data->orig.data);
-       kfree(data);
+       return 0;
 }
-NOKPROBE_SYMBOL(free_deref_fetch_param);
 
-/* Bitfield fetch function */
-struct bitfield_fetch_param {
-       struct fetch_param      orig;
-       unsigned char           hi_shift;
-       unsigned char           low_shift;
+/* Fetch type information table */
+static const struct fetch_type probe_fetch_types[] = {
+       /* Special types */
+       __ASSIGN_FETCH_TYPE("string", string, string, sizeof(u32), 1,
+                           "__data_loc char[]"),
+       /* Basic types */
+       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),
+       ASSIGN_FETCH_TYPE_ALIAS(x8,  u8,  u8,  0),
+       ASSIGN_FETCH_TYPE_ALIAS(x16, u16, u16, 0),
+       ASSIGN_FETCH_TYPE_ALIAS(x32, u32, u32, 0),
+       ASSIGN_FETCH_TYPE_ALIAS(x64, u64, u64, 0),
+
+       ASSIGN_FETCH_TYPE_END
 };
 
-#define DEFINE_FETCH_bitfield(type)                                    \
-void FETCH_FUNC_NAME(bitfield, type)(struct pt_regs *regs,             \
-                                    void *data, void *dest)            \
-{                                                                      \
-       struct bitfield_fetch_param *bprm = data;                       \
-       type buf = 0;                                                   \
-       call_fetch(&bprm->orig, regs, &buf);                            \
-       if (buf) {                                                      \
-               buf <<= bprm->hi_shift;                                 \
-               buf >>= bprm->low_shift;                                \
-       }                                                               \
-       *(type *)dest = buf;                                            \
-}                                                                      \
-NOKPROBE_SYMBOL(FETCH_FUNC_NAME(bitfield, type));
-DEFINE_BASIC_FETCH_FUNCS(bitfield)
-#define fetch_bitfield_string          NULL
-#define fetch_bitfield_string_size     NULL
-
-static void
-update_bitfield_fetch_param(struct bitfield_fetch_param *data)
-{
-       /*
-        * Don't check the bitfield itself, because this must be the
-        * last fetch function.
-        */
-       if (CHECK_FETCH_FUNCS(deref, data->orig.fn))
-               update_deref_fetch_param(data->orig.data);
-       else if (CHECK_FETCH_FUNCS(symbol, data->orig.fn))
-               update_symbol_cache(data->orig.data);
-}
-
-static void
-free_bitfield_fetch_param(struct bitfield_fetch_param *data)
-{
-       /*
-        * Don't check the bitfield itself, because this must be the
-        * last fetch function.
-        */
-       if (CHECK_FETCH_FUNCS(deref, data->orig.fn))
-               free_deref_fetch_param(data->orig.data);
-       else if (CHECK_FETCH_FUNCS(symbol, data->orig.fn))
-               free_symbol_cache(data->orig.data);
-
-       kfree(data);
-}
-
-void FETCH_FUNC_NAME(comm, string)(struct pt_regs *regs,
-                                         void *data, void *dest)
-{
-       int maxlen = get_rloc_len(*(u32 *)dest);
-       u8 *dst = get_rloc_data(dest);
-       long ret;
-
-       if (!maxlen)
-               return;
-
-       ret = strlcpy(dst, current->comm, maxlen);
-       *(u32 *)dest = make_data_rloc(ret, get_rloc_offs(*(u32 *)dest));
-}
-NOKPROBE_SYMBOL(FETCH_FUNC_NAME(comm, string));
-
-void FETCH_FUNC_NAME(comm, string_size)(struct pt_regs *regs,
-                                              void *data, void *dest)
-{
-       *(u32 *)dest = strlen(current->comm) + 1;
-}
-NOKPROBE_SYMBOL(FETCH_FUNC_NAME(comm, string_size));
-
-static const struct fetch_type *find_fetch_type(const char *type,
-                                               const struct fetch_type *ftbl)
+static const struct fetch_type *find_fetch_type(const char *type)
 {
        int i;
 
@@ -263,58 +128,27 @@ static const struct fetch_type *find_fetch_type(const 
char *type,
 
                switch (bs) {
                case 8:
-                       return find_fetch_type("u8", ftbl);
+                       return find_fetch_type("u8");
                case 16:
-                       return find_fetch_type("u16", ftbl);
+                       return find_fetch_type("u16");
                case 32:
-                       return find_fetch_type("u32", ftbl);
+                       return find_fetch_type("u32");
                case 64:
-                       return find_fetch_type("u64", ftbl);
+                       return find_fetch_type("u64");
                default:
                        goto fail;
                }
        }
 
-       for (i = 0; ftbl[i].name; i++) {
-               if (strcmp(type, ftbl[i].name) == 0)
-                       return &ftbl[i];
+       for (i = 0; probe_fetch_types[i].name; i++) {
+               if (strcmp(type, probe_fetch_types[i].name) == 0)
+                       return &probe_fetch_types[i];
        }
 
 fail:
        return NULL;
 }
 
-/* Special function : only accept unsigned long */
-static void fetch_kernel_stack_address(struct pt_regs *regs, void *dummy, void 
*dest)
-{
-       *(unsigned long *)dest = kernel_stack_pointer(regs);
-}
-NOKPROBE_SYMBOL(fetch_kernel_stack_address);
-
-static void fetch_user_stack_address(struct pt_regs *regs, void *dummy, void 
*dest)
-{
-       *(unsigned long *)dest = user_stack_pointer(regs);
-}
-NOKPROBE_SYMBOL(fetch_user_stack_address);
-
-static fetch_func_t get_fetch_size_function(const struct fetch_type *type,
-                                           fetch_func_t orig_fn,
-                                           const struct fetch_type *ftbl)
-{
-       int i;
-
-       if (type != &ftbl[FETCH_TYPE_STRING])
-               return NULL;    /* Only string type needs size function */
-
-       for (i = 0; i < FETCH_MTD_END; i++)
-               if (type->fetch[i] == orig_fn)
-                       return ftbl[FETCH_TYPE_STRSIZE].fetch[i];
-
-       WARN_ON(1);     /* This should not happen */
-
-       return NULL;
-}
-
 /* Split symbol and offset. */
 int traceprobe_split_symbol_offset(char *symbol, unsigned long *offset)
 {
@@ -341,7 +175,7 @@ int traceprobe_split_symbol_offset(char *symbol, unsigned 
long *offset)
 #define PARAM_MAX_STACK (THREAD_SIZE / sizeof(unsigned long))
 
 static int parse_probe_vars(char *arg, const struct fetch_type *t,
-                           struct fetch_param *f, bool is_return,
+                           struct fetch_insn *code, bool is_return,
                            bool is_kprobe)
 {
        int ret = 0;
@@ -349,33 +183,24 @@ static int parse_probe_vars(char *arg, const struct 
fetch_type *t,
 
        if (strcmp(arg, "retval") == 0) {
                if (is_return)
-                       f->fn = t->fetch[FETCH_MTD_retval];
+                       code->op = FETCH_OP_RETVAL;
                else
                        ret = -EINVAL;
        } else if (strncmp(arg, "stack", 5) == 0) {
                if (arg[5] == '\0') {
-                       if (strcmp(t->name, DEFAULT_FETCH_TYPE_STR))
-                               return -EINVAL;
-
-                       if (is_kprobe)
-                               f->fn = fetch_kernel_stack_address;
-                       else
-                               f->fn = fetch_user_stack_address;
+                       code->op = FETCH_OP_STACKP;
                } else if (isdigit(arg[5])) {
                        ret = kstrtoul(arg + 5, 10, &param);
                        if (ret || (is_kprobe && param > PARAM_MAX_STACK))
                                ret = -EINVAL;
                        else {
-                               f->fn = t->fetch[FETCH_MTD_stack];
-                               f->data = (void *)param;
+                               code->op = FETCH_OP_STACK;
+                               code->param = (unsigned int)param;
                        }
                } else
                        ret = -EINVAL;
        } else if (strcmp(arg, "comm") == 0) {
-               if (strcmp(t->name, "string") != 0 &&
-                   strcmp(t->name, "string_size") != 0)
-                       return -EINVAL;
-               f->fn = t->fetch[FETCH_MTD_comm];
+               code->op = FETCH_OP_COMM;
        } else
                ret = -EINVAL;
 
@@ -383,10 +208,12 @@ static int parse_probe_vars(char *arg, const struct 
fetch_type *t,
 }
 
 /* Recursive argument parser */
-static int parse_probe_arg(char *arg, const struct fetch_type *t,
-                    struct fetch_param *f, bool is_return, bool is_kprobe,
-                    const struct fetch_type *ftbl)
+static int
+parse_probe_arg(char *arg, const struct fetch_type *type,
+               struct fetch_insn **pcode, struct fetch_insn *end,
+               bool is_return, bool is_kprobe)
 {
+       struct fetch_insn *code = *pcode;
        unsigned long param;
        long offset;
        char *tmp;
@@ -394,14 +221,15 @@ static int parse_probe_arg(char *arg, const struct 
fetch_type *t,
 
        switch (arg[0]) {
        case '$':
-               ret = parse_probe_vars(arg + 1, t, f, is_return, is_kprobe);
+               ret = parse_probe_vars(arg + 1, type, code,
+                                       is_return, is_kprobe);
                break;
 
        case '%':       /* named register */
                ret = regs_query_register_offset(arg + 1);
                if (ret >= 0) {
-                       f->fn = t->fetch[FETCH_MTD_reg];
-                       f->data = (void *)(unsigned long)ret;
+                       code->op = FETCH_OP_REG;
+                       code->param = (unsigned int)ret;
                        ret = 0;
                }
                break;
@@ -411,9 +239,9 @@ static int parse_probe_arg(char *arg, const struct 
fetch_type *t,
                        ret = kstrtoul(arg + 1, 0, &param);
                        if (ret)
                                break;
-
-                       f->fn = t->fetch[FETCH_MTD_memory];
-                       f->data = (void *)param;
+                       /* load address */
+                       code->op = FETCH_OP_IMM;
+                       code->immediate = param;
                } else if (arg[1] == '+') {
                        /* kprobes don't support file offsets */
                        if (is_kprobe)
@@ -423,8 +251,8 @@ static int parse_probe_arg(char *arg, const struct 
fetch_type *t,
                        if (ret)
                                break;
 
-                       f->fn = t->fetch[FETCH_MTD_file_offset];
-                       f->data = (void *)offset;
+                       code->op = FETCH_OP_FOFFS;
+                       code->immediate = (unsigned long)offset;  // imm64?
                } else {
                        /* uprobes don't support symbols */
                        if (!is_kprobe)
@@ -434,10 +262,19 @@ static int parse_probe_arg(char *arg, const struct 
fetch_type *t,
                        if (ret)
                                break;
 
-                       f->data = alloc_symbol_cache(arg + 1, offset);
-                       if (f->data)
-                               f->fn = t->fetch[FETCH_MTD_symbol];
+                       code->op = FETCH_OP_IMM;
+                       code->immediate =
+                               (unsigned long)kallsyms_lookup_name(arg + 1);
+                       if (!code->immediate)
+                               return -ENOENT;
+                       code->immediate += offset;
                }
+               /* These are fetching from memory */
+               if (++code == end)
+                       return -E2BIG;
+               *pcode = code;
+               code->op = FETCH_OP_DEREF;
+               code->offset = offset;
                break;
 
        case '+':       /* deref memory */
@@ -445,11 +282,10 @@ static int parse_probe_arg(char *arg, const struct 
fetch_type *t,
        case '-':
                tmp = strchr(arg, '(');
                if (!tmp)
-                       break;
+                       return -EINVAL;
 
                *tmp = '\0';
                ret = kstrtol(arg, 0, &offset);
-
                if (ret)
                        break;
 
@@ -457,36 +293,28 @@ static int parse_probe_arg(char *arg, const struct 
fetch_type *t,
                tmp = strrchr(arg, ')');
 
                if (tmp) {
-                       struct deref_fetch_param        *dprm;
-                       const struct fetch_type         *t2;
+                       const struct fetch_type *t2 = find_fetch_type(NULL);
 
-                       t2 = find_fetch_type(NULL, ftbl);
                        *tmp = '\0';
-                       dprm = kzalloc(sizeof(struct deref_fetch_param), 
GFP_KERNEL);
-
-                       if (!dprm)
-                               return -ENOMEM;
-
-                       dprm->offset = offset;
-                       dprm->fetch = t->fetch[FETCH_MTD_memory];
-                       dprm->fetch_size = get_fetch_size_function(t,
-                                                       dprm->fetch, ftbl);
-                       ret = parse_probe_arg(arg, t2, &dprm->orig, is_return,
-                                                       is_kprobe, ftbl);
+                       ret = parse_probe_arg(arg, t2, &code, end, is_return,
+                                             is_kprobe);
                        if (ret)
-                               kfree(dprm);
-                       else {
-                               f->fn = t->fetch[FETCH_MTD_deref];
-                               f->data = (void *)dprm;
-                       }
+                               break;
+                       if (code->op == FETCH_OP_COMM)
+                               return -EINVAL;
+                       if (++code == end)
+                               return -E2BIG;
+                       *pcode = code;
+
+                       code->op = FETCH_OP_DEREF;
+                       code->offset = offset;
                }
                break;
        }
-       if (!ret && !f->fn) {   /* Parsed, but do not find fetch method */
-               pr_info("%s type has no corresponding fetch method.\n", 
t->name);
+       if (!ret && code->op == FETCH_OP_NOP) {
+               /* Parsed, but do not find fetch method */
                ret = -EINVAL;
        }
-
        return ret;
 }
 
@@ -495,22 +323,15 @@ static int parse_probe_arg(char *arg, const struct 
fetch_type *t,
 /* Bitfield type needs to be parsed into a fetch function */
 static int __parse_bitfield_probe_arg(const char *bf,
                                      const struct fetch_type *t,
-                                     struct fetch_param *f)
+                                     struct fetch_insn **pcode)
 {
-       struct bitfield_fetch_param *bprm;
+       struct fetch_insn *code = *pcode;
        unsigned long bw, bo;
        char *tail;
 
        if (*bf != 'b')
                return 0;
 
-       bprm = kzalloc(sizeof(*bprm), GFP_KERNEL);
-       if (!bprm)
-               return -ENOMEM;
-
-       bprm->orig = *f;
-       f->fn = t->fetch[FETCH_MTD_bitfield];
-       f->data = (void *)bprm;
        bw = simple_strtoul(bf + 1, &tail, 0);  /* Use simple one */
 
        if (bw == 0 || *tail != '@')
@@ -521,18 +342,24 @@ static int __parse_bitfield_probe_arg(const char *bf,
 
        if (tail == bf || *tail != '/')
                return -EINVAL;
+       code++;
+       if (code->op != FETCH_OP_NOP)
+               return -E2BIG;
+       *pcode = code;
 
-       bprm->hi_shift = BYTES_TO_BITS(t->size) - (bw + bo);
-       bprm->low_shift = bprm->hi_shift + bo;
+       code->op = FETCH_OP_MOD_BF;
+       code->lshift = BYTES_TO_BITS(t->size) - (bw + bo);
+       code->rshift = BYTES_TO_BITS(t->size) - bw;
+       code->basesize = t->size;
 
        return (BYTES_TO_BITS(t->size) < (bw + bo)) ? -EINVAL : 0;
 }
 
 /* String length checking wrapper */
 int traceprobe_parse_probe_arg(char *arg, ssize_t *size,
-               struct probe_arg *parg, bool is_return, bool is_kprobe,
-               const struct fetch_type *ftbl)
+               struct probe_arg *parg, bool is_return, bool is_kprobe)
 {
+       struct fetch_insn *code, *tmp = NULL;
        const char *t;
        int ret;
 
@@ -556,25 +383,70 @@ int traceprobe_parse_probe_arg(char *arg, ssize_t *size,
         */
        if (!t && strcmp(arg, "$comm") == 0)
                t = "string";
-       parg->type = find_fetch_type(t, ftbl);
+       parg->type = find_fetch_type(t);
        if (!parg->type) {
                pr_info("Unsupported type: %s\n", t);
                return -EINVAL;
        }
        parg->offset = *size;
        *size += parg->type->size;
-       ret = parse_probe_arg(arg, parg->type, &parg->fetch, is_return,
-                             is_kprobe, ftbl);
 
-       if (ret >= 0 && t != NULL)
-               ret = __parse_bitfield_probe_arg(t, parg->type, &parg->fetch);
+       code = tmp = kzalloc(sizeof(*code) * FETCH_INSN_MAX, GFP_KERNEL);
+       if (!code)
+               return -ENOMEM;
+       code[FETCH_INSN_MAX - 1].op = FETCH_OP_END;
+
+       ret = parse_probe_arg(arg, parg->type, &code, &code[FETCH_INSN_MAX - 1],
+                             is_return, is_kprobe);
+       if (ret)
+               goto fail;
 
-       if (ret >= 0) {
-               parg->fetch_size.fn = get_fetch_size_function(parg->type,
-                                                             parg->fetch.fn,
-                                                             ftbl);
-               parg->fetch_size.data = parg->fetch.data;
+       /* Store operation */
+       if (!strcmp(parg->type->name, "string")) {
+               if (code->op != FETCH_OP_DEREF && code->op != FETCH_OP_IMM) {
+                       pr_info("string only accepts memory or address.\n");
+                       ret = -EINVAL;
+                       goto fail;
+               }
+               if (code->op == FETCH_OP_IMM) {
+                       code++;
+                       if (code->op != FETCH_OP_NOP) {
+                               ret = -E2BIG;
+                               goto fail;
+                       }
+               }
+               code->op = FETCH_OP_ST_STRING;  /* In DEREF case, replace it */
+               parg->dynamic = true;
+       } else if (code->op == FETCH_OP_DEREF) {
+               code->op = FETCH_OP_ST_MEM;
+               code->size = parg->type->size;
+       } else {
+               code++;
+               if (code->op != FETCH_OP_NOP) {
+                       ret = -E2BIG;
+                       goto fail;
+               }
+               code->op = FETCH_OP_ST_RAW;
+               code->size = parg->type->size;
        }
+       /* Modify operation */
+       if (t != NULL) {
+               ret = __parse_bitfield_probe_arg(t, parg->type, &code);
+               if (ret)
+                       goto fail;
+       }
+       code++;
+       code->op = FETCH_OP_END;
+
+       /* Shrink down the code buffer */
+       parg->code = kzalloc(sizeof(*code) * (code - tmp + 1), GFP_KERNEL);
+       if (!parg->code)
+               ret = -ENOMEM;
+       else
+               memcpy(parg->code, tmp, sizeof(*code) * (code - tmp + 1));
+
+fail:
+       kfree(tmp);
 
        return ret;
 }
@@ -596,25 +468,9 @@ int traceprobe_conflict_field_name(const char *name,
        return 0;
 }
 
-void traceprobe_update_arg(struct probe_arg *arg)
-{
-       if (CHECK_FETCH_FUNCS(bitfield, arg->fetch.fn))
-               update_bitfield_fetch_param(arg->fetch.data);
-       else if (CHECK_FETCH_FUNCS(deref, arg->fetch.fn))
-               update_deref_fetch_param(arg->fetch.data);
-       else if (CHECK_FETCH_FUNCS(symbol, arg->fetch.fn))
-               update_symbol_cache(arg->fetch.data);
-}
-
 void traceprobe_free_probe_arg(struct probe_arg *arg)
 {
-       if (CHECK_FETCH_FUNCS(bitfield, arg->fetch.fn))
-               free_bitfield_fetch_param(arg->fetch.data);
-       else if (CHECK_FETCH_FUNCS(deref, arg->fetch.fn))
-               free_deref_fetch_param(arg->fetch.data);
-       else if (CHECK_FETCH_FUNCS(symbol, arg->fetch.fn))
-               free_symbol_cache(arg->fetch.data);
-
+       kfree(arg->code);
        kfree(arg->name);
        kfree(arg->comm);
 }
diff --git a/kernel/trace/trace_probe.h b/kernel/trace/trace_probe.h
index a1490e279658..b22792a6f889 100644
--- a/kernel/trace/trace_probe.h
+++ b/kernel/trace/trace_probe.h
@@ -91,25 +91,50 @@ static nokprobe_inline void *get_loc_data(u32 *dl, void 
*ent)
        return (u8 *)ent + get_rloc_offs(*dl);
 }
 
-/* Data fetch function type */
-typedef        void (*fetch_func_t)(struct pt_regs *, void *, void *);
 /* Printing function type */
 typedef int (*print_type_func_t)(struct trace_seq *, void *, void *);
 
-/* Fetch types */
-enum {
-       FETCH_MTD_reg = 0,
-       FETCH_MTD_stack,
-       FETCH_MTD_retval,
-       FETCH_MTD_comm,
-       FETCH_MTD_memory,
-       FETCH_MTD_symbol,
-       FETCH_MTD_deref,
-       FETCH_MTD_bitfield,
-       FETCH_MTD_file_offset,
-       FETCH_MTD_END,
+enum fetch_op {
+       FETCH_OP_NOP = 0,
+       // Stage 1 (load) ops
+       FETCH_OP_REG,           /* Register : .param = offset */
+       FETCH_OP_STACK,         /* Stack : .param = index */
+       FETCH_OP_STACKP,        /* Stack pointer */
+       FETCH_OP_RETVAL,        /* Return value */
+       FETCH_OP_IMM,           /* Immediate : .immediate */
+       FETCH_OP_COMM,          /* Current comm */
+       FETCH_OP_FOFFS,         /* File offset: .immediate */
+       // Stage 2 (dereference) op
+       FETCH_OP_DEREF,         /* Dereference: .offset */
+       // Stage 3 (store) ops
+       FETCH_OP_ST_RAW,        /* Raw: .size */
+       FETCH_OP_ST_MEM,        /* Mem: .offset, .size */
+       FETCH_OP_ST_STRING,     /* String: .offset, .size */
+       // Stage 4 (modify) op
+       FETCH_OP_MOD_BF,        /* Bitfield: .basesize, .lshift, .rshift */
+       FETCH_OP_END,
 };
 
+struct fetch_insn {
+       enum fetch_op op;
+       union {
+               unsigned int param;
+               struct {
+                       unsigned int size;
+                       int offset;
+               };
+               struct {
+                       unsigned char basesize;
+                       unsigned char lshift;
+                       unsigned char rshift;
+               };
+               unsigned long immediate;
+       };
+};
+
+/* fetch + deref*N + store + mod + end <= 16, this allows N=12, enough */
+#define FETCH_INSN_MAX 16
+
 /* Fetch type information table */
 struct fetch_type {
        const char              *name;          /* Name of type */
@@ -118,13 +143,6 @@ struct fetch_type {
        print_type_func_t       print;          /* Print functions */
        const char              *fmt;           /* Fromat string */
        const char              *fmttype;       /* Name in format file */
-       /* Fetch functions */
-       fetch_func_t            fetch[FETCH_MTD_END];
-};
-
-struct fetch_param {
-       fetch_func_t            fn;
-       void                    *data;
 };
 
 /* For defining macros, define string/string_size types */
@@ -154,66 +172,12 @@ DECLARE_BASIC_PRINT_TYPE_FUNC(x64);
 
 DECLARE_BASIC_PRINT_TYPE_FUNC(string);
 
-#define FETCH_FUNC_NAME(method, type)  fetch_##method##_##type
-
-/* Declare macro for basic types */
-#define DECLARE_FETCH_FUNC(method, type)                               \
-extern void FETCH_FUNC_NAME(method, type)(struct pt_regs *regs,        \
-                                         void *data, void *dest)
-
-#define DECLARE_BASIC_FETCH_FUNCS(method)      \
-DECLARE_FETCH_FUNC(method, u8);                        \
-DECLARE_FETCH_FUNC(method, u16);               \
-DECLARE_FETCH_FUNC(method, u32);               \
-DECLARE_FETCH_FUNC(method, u64)
-
-DECLARE_BASIC_FETCH_FUNCS(reg);
-#define fetch_reg_string                       NULL
-#define fetch_reg_string_size                  NULL
-
-DECLARE_BASIC_FETCH_FUNCS(retval);
-#define fetch_retval_string                    NULL
-#define fetch_retval_string_size               NULL
-
-DECLARE_BASIC_FETCH_FUNCS(symbol);
-DECLARE_FETCH_FUNC(symbol, string);
-DECLARE_FETCH_FUNC(symbol, string_size);
-
-DECLARE_BASIC_FETCH_FUNCS(deref);
-DECLARE_FETCH_FUNC(deref, string);
-DECLARE_FETCH_FUNC(deref, string_size);
-
-DECLARE_BASIC_FETCH_FUNCS(bitfield);
-#define fetch_bitfield_string                  NULL
-#define fetch_bitfield_string_size             NULL
-
-/* comm only makes sense as a string */
-#define fetch_comm_u8          NULL
-#define fetch_comm_u16         NULL
-#define fetch_comm_u32         NULL
-#define fetch_comm_u64         NULL
-DECLARE_FETCH_FUNC(comm, string);
-DECLARE_FETCH_FUNC(comm, string_size);
-
-/*
- * 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(method) \
-DEFINE_FETCH_##method(u8)              \
-DEFINE_FETCH_##method(u16)             \
-DEFINE_FETCH_##method(u32)             \
-DEFINE_FETCH_##method(u64)
-
 /* Default (unsigned long) fetch type */
 #define __DEFAULT_FETCH_TYPE(t) x##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(method, type)        \
-       [FETCH_MTD_##method] = FETCH_FUNC_NAME(method, type)
-
 #define __ASSIGN_FETCH_TYPE(_name, ptype, ftype, _size, sign, _fmttype)        
\
        {.name = _name,                         \
         .size = _size,                                 \
@@ -221,17 +185,6 @@ DEFINE_FETCH_##method(u64)
         .print = PRINT_TYPE_FUNC_NAME(ptype),          \
         .fmt = PRINT_TYPE_FMT_NAME(ptype),             \
         .fmttype = _fmttype,                           \
-        .fetch = {                                     \
-ASSIGN_FETCH_FUNC(reg, ftype),                         \
-ASSIGN_FETCH_FUNC(stack, ftype),                       \
-ASSIGN_FETCH_FUNC(retval, ftype),                      \
-ASSIGN_FETCH_FUNC(comm, ftype),                                \
-ASSIGN_FETCH_FUNC(memory, ftype),                      \
-ASSIGN_FETCH_FUNC(symbol, ftype),                      \
-ASSIGN_FETCH_FUNC(deref, ftype),                       \
-ASSIGN_FETCH_FUNC(bitfield, ftype),                    \
-ASSIGN_FETCH_FUNC(file_offset, ftype),                 \
-         }                                             \
        }
 
 #define ASSIGN_FETCH_TYPE(ptype, ftype, sign)                  \
@@ -243,44 +196,9 @@ ASSIGN_FETCH_FUNC(file_offset, ftype),                     
\
 
 #define ASSIGN_FETCH_TYPE_END {}
 
-#define FETCH_TYPE_STRING      0
-#define FETCH_TYPE_STRSIZE     1
-
-#ifdef CONFIG_KPROBE_EVENTS
-struct symbol_cache;
-unsigned long update_symbol_cache(struct symbol_cache *sc);
-void free_symbol_cache(struct symbol_cache *sc);
-struct symbol_cache *alloc_symbol_cache(const char *sym, long offset);
-#else
-/* uprobes do not support symbol fetch methods */
-#define fetch_symbol_u8                        NULL
-#define fetch_symbol_u16               NULL
-#define fetch_symbol_u32               NULL
-#define fetch_symbol_u64               NULL
-#define fetch_symbol_string            NULL
-#define fetch_symbol_string_size       NULL
-
-struct symbol_cache {
-};
-static inline unsigned long __used update_symbol_cache(struct symbol_cache *sc)
-{
-       return 0;
-}
-
-static inline void __used free_symbol_cache(struct symbol_cache *sc)
-{
-}
-
-static inline struct symbol_cache * __used
-alloc_symbol_cache(const char *sym, long offset)
-{
-       return NULL;
-}
-#endif /* CONFIG_KPROBE_EVENTS */
-
 struct probe_arg {
-       struct fetch_param      fetch;
-       struct fetch_param      fetch_size;
+       struct fetch_insn       *code;
+       bool                    dynamic;/* Dynamic array (string) is used */
        unsigned int            offset; /* Offset from argument entry */
        const char              *name;  /* Name of this argument */
        const char              *comm;  /* Command of this argument */
@@ -312,12 +230,6 @@ static inline bool trace_probe_is_registered(struct 
trace_probe *tp)
        return !!(tp->flags & TP_FLAG_REGISTERED);
 }
 
-static nokprobe_inline void call_fetch(struct fetch_param *fprm,
-                                struct pt_regs *regs, void *dest)
-{
-       return fprm->fn(regs, fprm->data, dest);
-}
-
 /* Check the name is good for event/group/fields */
 static inline bool is_good_name(const char *name)
 {
@@ -343,8 +255,7 @@ find_event_file_link(struct trace_probe *tp, struct 
trace_event_file *file)
 }
 
 extern int traceprobe_parse_probe_arg(char *arg, ssize_t *size,
-                  struct probe_arg *parg, bool is_return, bool is_kprobe,
-                  const struct fetch_type *ftbl);
+                  struct probe_arg *parg, bool is_return, bool is_kprobe);
 
 extern int traceprobe_conflict_field_name(const char *name,
                               struct probe_arg *args, int narg);
@@ -354,18 +265,72 @@ extern void traceprobe_free_probe_arg(struct probe_arg 
*arg);
 
 extern int traceprobe_split_symbol_offset(char *symbol, unsigned long *offset);
 
+/* traceprobe fetch helper  */
+static nokprobe_inline void
+fetch_store_raw(unsigned long val, struct fetch_insn *code, void *buf)
+{
+       switch (code->size) {
+       case 1:
+               *(u8 *)buf = (u8)val;
+               break;
+       case 2:
+               *(u16 *)buf = (u16)val;
+               break;
+       case 4:
+               *(u32 *)buf = (u32)val;
+               break;
+       case 8:
+               //TBD: 32bit signed
+               *(u64 *)buf = (u64)val;
+               break;
+       default:
+               *(unsigned long *)buf = val;
+       }
+}
+
+static nokprobe_inline void
+fetch_apply_bitfield(struct fetch_insn *code, void *buf)
+{
+       switch (code->basesize) {
+       case 1:
+               *(u8 *)buf <<= code->lshift;
+               *(u8 *)buf >>= code->rshift;
+               break;
+       case 2:
+               *(u16 *)buf <<= code->lshift;
+               *(u16 *)buf >>= code->rshift;
+               break;
+       case 4:
+               *(u32 *)buf <<= code->lshift;
+               *(u32 *)buf >>= code->rshift;
+               break;
+       case 8:
+               *(u64 *)buf <<= code->lshift;
+               *(u64 *)buf >>= code->rshift;
+               break;
+       }
+}
+
+/* Define this for each callsite */
+static int
+process_fetch_insn(struct fetch_insn *code, struct pt_regs *regs,
+                  void *dest, bool pre);
+
 /* Sum up total data length for dynamic arraies (strings) */
 static nokprobe_inline int
 __get_data_size(struct trace_probe *tp, struct pt_regs *regs)
 {
+       struct probe_arg *arg;
        int i, ret = 0;
        u32 len;
 
-       for (i = 0; i < tp->nr_args; i++)
-               if (unlikely(tp->args[i].fetch_size.fn)) {
-                       call_fetch(&tp->args[i].fetch_size, regs, &len);
+       for (i = 0; i < tp->nr_args; i++) {
+               arg = tp->args + i;
+               if (unlikely(arg->dynamic)) {
+                       process_fetch_insn(arg->code, regs, &len, true);
                        ret += len;
                }
+       }
 
        return ret;
 }
@@ -375,30 +340,31 @@ static nokprobe_inline void
 store_trace_args(int ent_size, struct trace_probe *tp, struct pt_regs *regs,
                 u8 *data, int maxlen)
 {
-       int i;
+       struct probe_arg *arg;
        u32 end = tp->size;
        u32 *dl;        /* Data (relative) location */
+       int i;
 
        for (i = 0; i < tp->nr_args; i++) {
-               if (unlikely(tp->args[i].fetch_size.fn)) {
+               arg = tp->args + i;
+               if (unlikely(arg->dynamic)) {
                        /*
                         * First, we set the relative location and
                         * maximum data length to *dl
                         */
-                       dl = (u32 *)(data + tp->args[i].offset);
-                       *dl = make_data_rloc(maxlen, end - tp->args[i].offset);
+                       dl = (u32 *)(data + arg->offset);
+                       *dl = make_data_rloc(maxlen, end - arg->offset);
                        /* Then try to fetch string or dynamic array data */
-                       call_fetch(&tp->args[i].fetch, regs, dl);
+                       process_fetch_insn(arg->code, regs, dl, false);
                        /* Reduce maximum length */
                        end += get_rloc_len(*dl);
                        maxlen -= get_rloc_len(*dl);
                        /* Trick here, convert data_rloc to data_loc */
-                       *dl = convert_rloc_to_loc(*dl,
-                                ent_size + tp->args[i].offset);
+                       *dl = convert_rloc_to_loc(*dl, ent_size + arg->offset);
                } else
                        /* Just fetching data normally */
-                       call_fetch(&tp->args[i].fetch, regs,
-                                  data + tp->args[i].offset);
+                       process_fetch_insn(arg->code, regs, data + arg->offset,
+                                          false);
        }
 }
 
diff --git a/kernel/trace/trace_uprobe.c b/kernel/trace/trace_uprobe.c
index 968bd403d68c..84692f564062 100644
--- a/kernel/trace/trace_uprobe.c
+++ b/kernel/trace/trace_uprobe.c
@@ -109,37 +109,19 @@ static unsigned long get_user_stack_nth(struct pt_regs 
*regs, unsigned int n)
 /*
  * Uprobes-specific fetch functions
  */
-#define DEFINE_FETCH_stack(type)                                       \
-static void FETCH_FUNC_NAME(stack, type)(struct pt_regs *regs,         \
-                                        void *offset, void *dest)      \
-{                                                                      \
-       *(type *)dest = (type)get_user_stack_nth(regs,                  \
-                                             ((unsigned long)offset)); \
-}
-DEFINE_BASIC_FETCH_FUNCS(stack)
-/* No string on the stack entry */
-#define fetch_stack_string     NULL
-#define fetch_stack_string_size        NULL
-
-#define DEFINE_FETCH_memory(type)                                      \
-static void FETCH_FUNC_NAME(memory, type)(struct pt_regs *regs,                
\
-                                         void *addr, void *dest)       \
-{                                                                      \
-       type retval;                                                    \
-       void __user *vaddr = (void __force __user *) addr;              \
-                                                                       \
-       if (copy_from_user(&retval, vaddr, sizeof(type)))               \
-               *(type *)dest = 0;                                      \
-       else                                                            \
-               *(type *) dest = retval;                                \
+static nokprobe_inline int
+probe_user_read(void *dest, void *src, size_t size)
+{
+       void __user *vaddr = (void __force __user *)src;
+
+       return copy_from_user(dest, vaddr, size);
 }
-DEFINE_BASIC_FETCH_FUNCS(memory)
 /*
  * Fetch a null-terminated string. Caller MUST set *(u32 *)dest with max
  * length and relative data location.
  */
-static void FETCH_FUNC_NAME(memory, string)(struct pt_regs *regs,
-                                           void *addr, void *dest)
+static nokprobe_inline void
+fetch_store_string(unsigned long addr, void *dest)
 {
        long ret;
        u32 rloc = *(u32 *)dest;
@@ -160,8 +142,9 @@ static void FETCH_FUNC_NAME(memory, string)(struct pt_regs 
*regs,
        }
 }
 
-static void FETCH_FUNC_NAME(memory, string_size)(struct pt_regs *regs,
-                                                void *addr, void *dest)
+/* Return the length of string -- including null terminal byte */
+static nokprobe_inline void
+fetch_store_strlen(unsigned long addr, void *dest)
 {
        int len;
        void __user *vaddr = (void __force __user *) addr;
@@ -174,7 +157,7 @@ static void FETCH_FUNC_NAME(memory, string_size)(struct 
pt_regs *regs,
                *(u32 *)dest = len;
 }
 
-static unsigned long translate_user_vaddr(void *file_offset)
+static unsigned long translate_user_vaddr(unsigned long file_offset)
 {
        unsigned long base_addr;
        struct uprobe_dispatch_data *udd;
@@ -182,44 +165,79 @@ static unsigned long translate_user_vaddr(void 
*file_offset)
        udd = (void *) current->utask->vaddr;
 
        base_addr = udd->bp_addr - udd->tu->offset;
-       return base_addr + (unsigned long)file_offset;
+       return base_addr + file_offset;
 }
 
-#define DEFINE_FETCH_file_offset(type)                                 \
-static void FETCH_FUNC_NAME(file_offset, type)(struct pt_regs *regs,   \
-                                              void *offset, void *dest)\
-{                                                                      \
-       void *vaddr = (void *)translate_user_vaddr(offset);             \
-                                                                       \
-       FETCH_FUNC_NAME(memory, type)(regs, vaddr, dest);               \
+/* Note that we don't verify it, since the code does not come from user space 
*/
+static int
+process_fetch_insn(struct fetch_insn *code, struct pt_regs *regs, void *dest,
+                  bool pre)
+{
+       unsigned long val;
+       int ret;
+
+       /* 1st stage: get value from context */
+       switch (code->op) {
+       case FETCH_OP_REG:
+               val = regs_get_register(regs, code->param);
+               break;
+       case FETCH_OP_STACK:
+               val = get_user_stack_nth(regs, code->param);
+               break;
+       case FETCH_OP_STACKP:
+               val = user_stack_pointer(regs);
+               break;
+       case FETCH_OP_RETVAL:
+               val = regs_return_value(regs);
+               break;
+       case FETCH_OP_IMM:
+               val = code->immediate;
+               break;
+       case FETCH_OP_FOFFS:
+               val = translate_user_vaddr(code->immediate);
+               break;
+       default:
+               return -EILSEQ;
+       }
+       code++;
+
+       /* 2nd stage: dereference memory if needed */
+       while (code->op == FETCH_OP_DEREF) {
+               ret = probe_user_read(&val, (void *)val + code->offset,
+                                     sizeof(val));
+               if (ret)
+                       return ret;
+               code++;
+       }
+
+       /* 3rd stage: store value to buffer */
+       switch (code->op) {
+       case FETCH_OP_ST_RAW:
+               fetch_store_raw(val, code, dest);
+               break;
+       case FETCH_OP_ST_MEM:
+               probe_user_read(dest, (void *)val + code->offset, code->size);
+               break;
+       case FETCH_OP_ST_STRING:
+               if (pre)
+                       fetch_store_strlen(val + code->offset, dest);
+               else
+                       fetch_store_string(val + code->offset, dest);
+               break;
+       default:
+               return -EILSEQ;
+       }
+       code++;
+
+       /* 4th stage: modify stored value if needed */
+       if (code->op == FETCH_OP_MOD_BF) {
+               fetch_apply_bitfield(code, dest);
+               code++;
+       }
+
+       return code->op == FETCH_OP_END ? 0 : -EILSEQ;
 }
-DEFINE_BASIC_FETCH_FUNCS(file_offset)
-DEFINE_FETCH_file_offset(string)
-DEFINE_FETCH_file_offset(string_size)
-
-/* Fetch type information table */
-static const struct fetch_type uprobes_fetch_type_table[] = {
-       /* Special types */
-       [FETCH_TYPE_STRING] = __ASSIGN_FETCH_TYPE("string", string, string,
-                                       sizeof(u32), 1, "__data_loc char[]"),
-       [FETCH_TYPE_STRSIZE] = __ASSIGN_FETCH_TYPE("string_size", u32,
-                                       string_size, sizeof(u32), 0, "u32"),
-       /* Basic types */
-       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),
-       ASSIGN_FETCH_TYPE_ALIAS(x8,  u8,  u8,  0),
-       ASSIGN_FETCH_TYPE_ALIAS(x16, u16, u16, 0),
-       ASSIGN_FETCH_TYPE_ALIAS(x32, u32, u32, 0),
-       ASSIGN_FETCH_TYPE_ALIAS(x64, u64, u64, 0),
-
-       ASSIGN_FETCH_TYPE_END
-};
+NOKPROBE_SYMBOL(process_fetch_insn)
 
 static inline void init_trace_uprobe_filter(struct trace_uprobe_filter *filter)
 {
@@ -538,8 +556,7 @@ static int create_trace_uprobe(int argc, char **argv)
 
                /* Parse fetch argument */
                ret = traceprobe_parse_probe_arg(arg, &tu->tp.size, parg,
-                                                is_return, false,
-                                                uprobes_fetch_type_table);
+                                                is_return, false);
                if (ret) {
                        pr_info("Parse error at argument[%d]. (%d)\n", i, ret);
                        goto error;

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