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    Subject[PATCH v7 04/16] tracing: probeevent: Introduce new argument fetching code
    Date
    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 <mhiramat@kernel.org>
    ---
    Changes in v3:
    - Split out probe type table unification.
    ---
    kernel/trace/trace_kprobe.c | 291 +++++++++++++---------------
    kernel/trace/trace_probe.c | 401 +++++++++++----------------------------
    kernel/trace/trace_probe.h | 230 ++++------------------
    kernel/trace/trace_probe_tmpl.h | 120 ++++++++++++
    kernel/trace/trace_uprobe.c | 127 ++++++++----
    5 files changed, 491 insertions(+), 678 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 a8f8cce066a9..1d1e37058f8a 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
    @@ -121,160 +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 */
    @@ -490,14 +337,11 @@ 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 +674,8 @@ 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,
    + kprobes_fetch_type_table);
    if (ret) {
    pr_info("Parse error at argument[%d]. (%d)\n", i, ret);
    goto error;
    @@ -985,6 +829,133 @@ 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 51ca8f751332..758968ac165d 100644
    --- a/kernel/trace/trace_probe.c
    +++ b/kernel/trace/trace_probe.c
    @@ -73,174 +73,6 @@ 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;
    -};
    -
    -#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)
    {
    @@ -284,37 +116,6 @@ static const struct fetch_type *find_fetch_type(const char *type,
    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)
    {
    @@ -339,7 +140,7 @@ 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;
    @@ -347,33 +148,24 @@ 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;

    @@ -381,10 +173,13 @@ 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,
    + const struct fetch_type *ftbl)
    {
    + struct fetch_insn *code = *pcode;
    unsigned long param;
    long offset;
    char *tmp;
    @@ -392,14 +187,15 @@ 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;
    @@ -409,9 +205,9 @@ 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)
    @@ -421,8 +217,8 @@ 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)
    @@ -432,10 +228,19 @@ 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 */
    @@ -443,11 +248,10 @@ 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;

    @@ -455,36 +259,29 @@ 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;

    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, ftbl);
    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;
    }

    @@ -493,22 +290,15 @@ 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 != '@')
    @@ -519,9 +309,15 @@ 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;
    }
    @@ -531,6 +327,7 @@ 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 fetch_insn *code, *tmp = NULL;
    const char *t;
    int ret;

    @@ -561,18 +358,60 @@ int traceprobe_parse_probe_arg(char *arg, ssize_t *size,
    }
    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, ftbl);
    + 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;
    }
    @@ -594,25 +433,9 @@ 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..9d9de7535d06 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 +196,13 @@ ASSIGN_FETCH_FUNC(file_offset, ftype), \

    #define ASSIGN_FETCH_TYPE_END {}

    -#define FETCH_TYPE_STRING 0
    -#define FETCH_TYPE_STRSIZE 1
    +#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 +215,8 @@ 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 +248,6 @@ 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)
    {
    @@ -366,68 +284,6 @@ 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 c21c3783d055..ff408edd3a68 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;
    @@ -162,8 +145,9 @@ 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;
    @@ -176,7 +160,7 @@ 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;
    @@ -184,21 +168,9 @@ 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); \
    -}
    -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 */
    @@ -223,6 +195,77 @@ static const struct fetch_type uprobes_fetch_type_table[] = {
    ASSIGN_FETCH_TYPE_END
    };

    +/* 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;
    +}
    +NOKPROBE_SYMBOL(process_fetch_insn)
    +
    static inline void init_trace_uprobe_filter(struct trace_uprobe_filter *filter)
    {
    rwlock_init(&filter->rwlock);
    \
     
     \ /
      Last update: 2018-04-25 14:19    [W:2.989 / U:0.028 seconds]
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