On Wed, Feb 21, 2018 at 11:57:36PM +0900, Masami Hiramatsu wrote:
> 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.

I think it'd be nice to split this commit to 3 parts:

 * convert to the fetch_insn
 * remove fetch methods (now unused)
 * unify fetch type table

Thanks,
Namhyung


> 
> Signed-off-by: Masami Hiramatsu <mhira...@kernel.org>
> ---
>  Changes in v2:
>   - Allow $comm:string.
> ---
>  kernel/trace/trace_kprobe.c     |  314 +++++++++++-----------------
>  kernel/trace/trace_probe.c      |  441 
> ++++++++++++---------------------------
>  kernel/trace/trace_probe.h      |  232 ++++-----------------
>  kernel/trace/trace_probe_tmpl.h |  120 +++++++++++
>  kernel/trace/trace_uprobe.c     |  150 +++++++------
>  5 files changed, 517 insertions(+), 740 deletions(-)
>  create mode 100644 kernel/trace/trace_probe_tmpl.h
> 
> diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c
> index a96328dfc012..5dd2d470cc7e 100644
> --- a/kernel/trace/trace_kprobe.c
> +++ b/kernel/trace/trace_kprobe.c
> @@ -24,6 +24,7 @@
>  #include <linux/error-injection.h>
>  
>  #include "trace_probe.h"
> +#include "trace_probe_tmpl.h"
>  
>  #define KPROBE_EVENT_SYSTEM "kprobes"
>  #define KRETPROBE_MAXACTIVE_MAX 4096
> @@ -121,184 +122,6 @@ 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).
>   */
> @@ -490,14 +313,11 @@ 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;
> @@ -830,8 +650,7 @@ 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;
> @@ -985,6 +804,133 @@ 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 37bdd56b4988..cd87490b3492 100644
> --- a/kernel/trace/trace_probe.c
> +++ b/kernel/trace/trace_probe.c
> @@ -73,176 +73,29 @@ 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);
> -
> -static void free_deref_fetch_param(struct deref_fetch_param *data)
> -{
> -     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);
> -}
> -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 +116,27 @@ 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, long *offset)
>  {
> @@ -341,7 +163,7 @@ int traceprobe_split_symbol_offset(char *symbol, 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 +171,24 @@ 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 +196,12 @@ 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 +209,15 @@ 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 +227,9 @@ 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 +239,8 @@ 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 +250,19 @@ 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 +270,10 @@ 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 +281,28 @@ 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 +311,15 @@ 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 +330,24 @@ 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 +371,67 @@ 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);
>  
> -     if (ret >= 0) {
> -             parg->fetch_size.fn = get_fetch_size_function(parg->type,
> -                                                           parg->fetch.fn,
> -                                                           ftbl);
> -             parg->fetch_size.data = parg->fetch.data;
> +     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;
> +
> +     /* Store operation */
> +     if (!strcmp(parg->type->name, "string")) {
> +             if (code->op != FETCH_OP_DEREF && code->op != FETCH_OP_IMM &&
> +                 code->op != FETCH_OP_COMM) {
> +                     pr_info("string only accepts memory or address.\n");
> +                     ret = -EINVAL;
> +                     goto fail;
> +             }
> +             /* Since IMM or COMM must be the 1st insn, this is safe */
> +             if (code->op == FETCH_OP_IMM || code->op == FETCH_OP_COMM)
> +                     code++;
> +             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 +453,9 @@ 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 de928052926b..89d853ef5174 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)                        \
> @@ -243,42 +196,10 @@ 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);
>  bool trace_kprobe_on_func_entry(struct trace_event_call *call);
>  bool trace_kprobe_error_injectable(struct trace_event_call *call);
>  #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;
> -}
> -
>  static inline bool trace_kprobe_on_func_entry(struct trace_event_call *call)
>  {
>       return false;
> @@ -291,8 +212,8 @@ static inline bool trace_kprobe_error_injectable(struct 
> trace_event_call *call)
>  #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 */
> @@ -324,12 +245,6 @@ 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)
>  {
> @@ -355,8 +270,7 @@ 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);
> @@ -366,68 +280,6 @@ extern void traceprobe_free_probe_arg(struct probe_arg 
> *arg);
>  
>  extern int traceprobe_split_symbol_offset(char *symbol, long *offset);
>  
> -/* Sum up total data length for dynamic arraies (strings) */
> -static nokprobe_inline int
> -__get_data_size(struct trace_probe *tp, struct pt_regs *regs)
> -{
> -     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);
> -                     ret += len;
> -             }
> -
> -     return ret;
> -}
> -
> -/* Store the value of each argument */
> -static nokprobe_inline void
> -store_trace_args(int ent_size, struct trace_probe *tp, struct pt_regs *regs,
> -              u8 *data, int maxlen)
> -{
> -     int i;
> -     u32 end = tp->size;
> -     u32 *dl;        /* Data (relative) location */
> -
> -     for (i = 0; i < tp->nr_args; i++) {
> -             if (unlikely(tp->args[i].fetch_size.fn)) {
> -                     /*
> -                      * 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);
> -                     /* Then try to fetch string or dynamic array data */
> -                     call_fetch(&tp->args[i].fetch, regs, dl);
> -                     /* 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);
> -             } else
> -                     /* Just fetching data normally */
> -                     call_fetch(&tp->args[i].fetch, regs,
> -                                data + tp->args[i].offset);
> -     }
> -}
> -
> -static inline int
> -print_probe_args(struct trace_seq *s, struct probe_arg *args, int nr_args,
> -              u8 *data, void *field)
> -{
> -     int i;
> -
> -     for (i = 0; i < nr_args; i++) {
> -             trace_seq_printf(s, " %s=", args[i].name);
> -             if (!args[i].type->print(s, data + args[i].offset, field))
> -                     return -ENOMEM;
> -     }
> -     return 0;
> -}
> -
>  extern int set_print_fmt(struct trace_probe *tp, bool is_return);
>  
>  #ifdef CONFIG_PERF_EVENTS
> diff --git a/kernel/trace/trace_probe_tmpl.h b/kernel/trace/trace_probe_tmpl.h
> new file mode 100644
> index 000000000000..c8a5272abf01
> --- /dev/null
> +++ b/kernel/trace/trace_probe_tmpl.h
> @@ -0,0 +1,120 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +/*
> + * Traceprobe fetch helper inlines
> + */
> +
> +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++) {
> +             arg = tp->args + i;
> +             if (unlikely(arg->dynamic)) {
> +                     process_fetch_insn(arg->code, regs, &len, true);
> +                     ret += len;
> +             }
> +     }
> +
> +     return ret;
> +}
> +
> +/* Store the value of each argument */
> +static nokprobe_inline void
> +store_trace_args(int ent_size, struct trace_probe *tp, struct pt_regs *regs,
> +              u8 *data, int maxlen)
> +{
> +     struct probe_arg *arg;
> +     u32 end = tp->size;
> +     u32 *dl;        /* Data (relative) location */
> +     int i;
> +
> +     for (i = 0; i < tp->nr_args; i++) {
> +             arg = tp->args + i;
> +             if (unlikely(arg->dynamic)) {
> +                     /*
> +                      * First, we set the relative location and
> +                      * maximum data length to *dl
> +                      */
> +                     dl = (u32 *)(data + arg->offset);
> +                     *dl = make_data_rloc(maxlen, end - arg->offset);
> +                     /* Then try to fetch string or dynamic array data */
> +                     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 + arg->offset);
> +             } else
> +                     /* Just fetching data normally */
> +                     process_fetch_insn(arg->code, regs, data + arg->offset,
> +                                        false);
> +     }
> +}
> +
> +static inline int
> +print_probe_args(struct trace_seq *s, struct probe_arg *args, int nr_args,
> +              u8 *data, void *field)
> +{
> +     int i;
> +
> +     for (i = 0; i < nr_args; i++) {
> +             trace_seq_printf(s, " %s=", args[i].name);
> +             if (!args[i].type->print(s, data + args[i].offset, field))
> +                     return -ENOMEM;
> +     }
> +     return 0;
> +}
> diff --git a/kernel/trace/trace_uprobe.c b/kernel/trace/trace_uprobe.c
> index 887da2bb63aa..9fc0123c721f 100644
> --- a/kernel/trace/trace_uprobe.c
> +++ b/kernel/trace/trace_uprobe.c
> @@ -27,6 +27,7 @@
>  #include <linux/rculist.h>
>  
>  #include "trace_probe.h"
> +#include "trace_probe_tmpl.h"
>  
>  #define UPROBE_EVENT_SYSTEM  "uprobes"
>  
> @@ -109,37 +110,19 @@ 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 +143,9 @@ 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 +158,7 @@ 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 +166,79 @@ 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 +557,7 @@ 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;
> 

Reply via email to