[for-next][PATCH 04/18] tracing: probeevent: Introduce new argument fetching code

From: Steven Rostedt
Date: Sun Oct 28 2018 - 03:32:13 EST

From: Masami Hiramatsu <mhiramat@xxxxxxxxxx>

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.

Link: http://lkml.kernel.org/r/152465868340.26224.2551120475197839464.stgit@devbox

Signed-off-by: Masami Hiramatsu <mhiramat@xxxxxxxxxx>
Signed-off-by: Steven Rostedt (VMware) <rostedt@xxxxxxxxxxx>
---
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 1356927e32d0..c024cc40d509 100644
--- a/kernel/trace/trace_kprobe.c
+++ b/kernel/trace/trace_kprobe.c
@@ -14,6 +14,7 @@

#include "trace_kprobe_selftest.h"
#include "trace_probe.h"
+#include "trace_probe_tmpl.h"

#define KPROBE_EVENT_SYSTEM "kprobes"
#define KRETPROBE_MAXACTIVE_MAX 4096
@@ -120,160 +121,6 @@ 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 */
@@ -529,7 +376,7 @@ static bool within_notrace_func(struct trace_kprobe *tk)
/* 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;
@@ -540,9 +387,6 @@ static int __register_trace_kprobe(struct trace_kprobe *tk)
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;
@@ -876,8 +720,8 @@ 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;
@@ -1031,6 +875,133 @@ 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 5f3b5b3fd2cd..c59c69cb2f2e 100644
--- a/kernel/trace/trace_probe.c
+++ b/kernel/trace/trace_probe.c
@@ -61,174 +61,6 @@ 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)
{
@@ -272,37 +104,6 @@ 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)
{
@@ -327,7 +128,7 @@ 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;
@@ -335,33 +136,24 @@ 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;

@@ -369,10 +161,13 @@ 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;
@@ -380,14 +175,15 @@ 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;
@@ -397,9 +193,9 @@ 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)
@@ -409,8 +205,8 @@ 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)
@@ -420,10 +216,19 @@ 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 */
@@ -431,11 +236,10 @@ 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;

@@ -443,36 +247,29 @@ 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;
}

@@ -481,22 +278,15 @@ 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 != '@')
@@ -507,9 +297,15 @@ 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;
}
@@ -519,6 +315,7 @@ 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;

@@ -549,18 +346,60 @@ 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;
}
@@ -582,25 +421,9 @@ 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 a1df7763b797..42c724a7ad11 100644
--- a/kernel/trace/trace_probe.h
+++ b/kernel/trace/trace_probe.h
@@ -79,25 +79,50 @@ 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 */
@@ -106,13 +131,6 @@ 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 */
@@ -142,66 +160,12 @@ 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, \
@@ -209,17 +173,6 @@ 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) \
@@ -231,42 +184,13 @@ 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;
@@ -279,8 +203,8 @@ 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 */
@@ -312,12 +236,6 @@ 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)
{
@@ -354,68 +272,6 @@ 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 28a8f69cec89..e076f89ab33a 100644
--- a/kernel/trace/trace_uprobe.c
+++ b/kernel/trace/trace_uprobe.c
@@ -15,6 +15,7 @@
#include <linux/rculist.h>

#include "trace_probe.h"
+#include "trace_probe_tmpl.h"

#define UPROBE_EVENT_SYSTEM "uprobes"

@@ -99,37 +100,19 @@ 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;
@@ -152,8 +135,9 @@ 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;
@@ -166,7 +150,7 @@ 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;
@@ -174,21 +158,9 @@ 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 */
@@ -213,6 +185,77 @@ 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);
--
2.19.0