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Commit 53305928 authored by Masami Hiramatsu's avatar Masami Hiramatsu Committed by Steven Rostedt (VMware)
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tracing: probeevent: Introduce new argument fetching code 

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: default avatarMasami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: default avatarSteven Rostedt (VMware) <rostedt@goodmis.org>
parent 7bfbc63e

kernel/trace/trace_kprobe.c

+131 −160
Original line number Diff line number Diff line
@@ -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;
@@ -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,

kernel/trace/trace_probe.c

+112 −289
Original line number Diff line number Diff line
@@ -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,

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;



			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,

			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);

	code = tmp = kzalloc(sizeof(*code) * FETCH_INSN_MAX, GFP_KERNEL);

	if (!code)

		return -ENOMEM;

	code[FETCH_INSN_MAX - 1].op = FETCH_OP_END;



	if (ret >= 0) {

		parg->fetch_size.fn = get_fetch_size_function(parg->type,

							      parg->fetch.fn,

							      ftbl);

		parg->fetch_size.data = parg->fetch.data;

	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);

}

kernel/trace/trace_probe.h

+43 −187

File changed.

Preview size limit exceeded, changes collapsed.

kernel/trace/trace_probe_tmpl.h

0 → 100644
+120 −0
Original line number Diff line number Diff line 
/* 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;

}

kernel/trace/trace_uprobe.c

+85 −42

File changed.

Preview size limit exceeded, changes collapsed.