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From: Masami Hiramatsu <mhiramat@kernel.org>
To: Steven Rostedt <rostedt@goodmis.org>, linux-kernel@vger.kernel.org
Cc: mhiramat@kernel.org, Ingo Molnar <mingo@redhat.com>,
	Namhyung Kim <namhyung@kernel.org>,
	Tom Zanussi <tom.zanussi@linux.intel.com>,
	Arnaldo Carvalho de Melo <acme@kernel.org>,
	linux-trace-users@vger.kernel.org,
	linux-kselftest@vger.kernel.org, shuah@kernel.org,
	Ravi Bangoria <ravi.bangoria@linux.vnet.ibm.com>
Subject: [PATCH v6 08/21] tracing: probeevent: Introduce new argument fetching code
Date: Sat, 17 Mar 2018 21:43:33 +0900
Message-ID: <152129061380.31874.13588860837129836504.stgit@devbox> (raw)
In-Reply-To: <152129024033.31874.15800253385376959274.stgit@devbox>

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 887da2bb63aa..e1bc33c5cd99 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;
@@ -182,21 +166,9 @@ 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 */
@@ -221,6 +193,77 @@ 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);


  parent reply index

Thread overview: 34+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-03-17 12:37 [PATCH v6 00/21] tracing: probeevent: Improve fetcharg features Masami Hiramatsu
2018-03-17 12:38 ` [PATCH v6 01/21] [BUGFIX] tracing: probeevent: Fix to support minus offset from symbol Masami Hiramatsu
2018-03-17 12:38 ` [PATCH v6 02/21] selftests: ftrace: Add probe event argument syntax testcase Masami Hiramatsu
2018-03-17 12:39 ` [PATCH v6 03/21] selftests: ftrace: Add a testcase for string type with kprobe_event Masami Hiramatsu
2018-03-17 12:40 ` [PATCH v6 04/21] selftests: ftrace: Add a testcase for probepoint Masami Hiramatsu
2018-03-23 16:19   ` Steven Rostedt
2018-03-17 12:41 ` [PATCH v6 05/21] tracing: probeevent: Cleanup print argument functions Masami Hiramatsu
2018-03-23 16:36   ` Steven Rostedt
2018-03-26  4:17     ` Masami Hiramatsu
2018-03-26 17:28       ` Steven Rostedt
2018-03-28  4:21         ` Masami Hiramatsu
2018-03-17 12:41 ` [PATCH v6 06/21] tracing: probeevent: Cleanup argument field definition Masami Hiramatsu
2018-03-17 12:42 ` [PATCH v6 07/21] tracing: probeevent: Remove NOKPROBE_SYMBOL from print functions Masami Hiramatsu
2018-03-17 12:43 ` Masami Hiramatsu [this message]
2018-03-17 12:44 ` [PATCH v6 09/21] tracing: probeevent: Unify fetch type tables Masami Hiramatsu
2018-03-17 12:44 ` [PATCH v6 10/21] tracing: probeevent: Return consumed bytes of dynamic area Masami Hiramatsu
2018-04-02 20:02   ` Steven Rostedt
2018-04-03 14:41     ` Masami Hiramatsu
2018-03-17 12:45 ` [PATCH v6 11/21] tracing: probeevent: Append traceprobe_ for exported function Masami Hiramatsu
2018-03-17 12:46 ` [PATCH v6 12/21] tracing: probeevent: Unify fetch_insn processing common part Masami Hiramatsu
2018-03-17 12:47 ` [PATCH v6 13/21] tracing: probeevent: Add symbol type Masami Hiramatsu
2018-03-17 12:47 ` [PATCH v6 14/21] x86: ptrace: Add function argument access API Masami Hiramatsu
2018-03-17 12:48 ` [PATCH v6 15/21] tracing: probeevent: Add $argN for accessing function args Masami Hiramatsu
2018-03-17 12:49 ` [PATCH v6 16/21] tracing: probeevent: Add array type support Masami Hiramatsu
2018-03-17 12:50 ` [PATCH v6 17/21] selftests: ftrace: Add a testcase for symbol type Masami Hiramatsu
2018-03-17 12:50 ` [PATCH v6 18/21] selftests: ftrace: Add a testcase for $argN with kprobe_event Masami Hiramatsu
2018-03-17 12:51 ` [PATCH v6 19/21] selftests: ftrace: Add a testcase for array type " Masami Hiramatsu
2018-03-17 12:53 ` [PATCH v6 21/21] perf-probe: Add array argument support Masami Hiramatsu
2018-03-19  7:59   ` Ravi Bangoria
2018-03-22 10:23     ` Masami Hiramatsu
2018-03-22 10:49       ` Ravi Bangoria
2018-03-26  3:53         ` Masami Hiramatsu
2018-03-17 14:06 ` [PATCH v6 00/21] tracing: probeevent: Improve fetcharg features Masami Hiramatsu
2018-03-17 12:52 [PATCH v6 20/21] [RESEND] perf-probe: Fix to convert array type collectly Masami Hiramatsu
2018-03-20  6:36 ` [tip:perf/core] perf probe: Use right type to access array elements tip-bot for Masami Hiramatsu

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