1 // SPDX-License-Identifier: GPL-2.0
3 * Common code for probe-based Dynamic events.
5 * This code was copied from kernel/trace/trace_kprobe.c written by
6 * Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
8 * Updates to make this generic:
9 * Copyright (C) IBM Corporation, 2010-2011
10 * Author: Srikar Dronamraju
12 #define pr_fmt(fmt) "trace_probe: " fmt
14 #include "trace_probe.h"
16 static const char *reserved_field_names[] = {
19 "common_preempt_count",
27 /* Printing in basic type function template */
28 #define DEFINE_BASIC_PRINT_TYPE_FUNC(tname, type, fmt) \
29 int PRINT_TYPE_FUNC_NAME(tname)(struct trace_seq *s, void *data, void *ent)\
31 trace_seq_printf(s, fmt, *(type *)data); \
32 return !trace_seq_has_overflowed(s); \
34 const char PRINT_TYPE_FMT_NAME(tname)[] = fmt;
36 DEFINE_BASIC_PRINT_TYPE_FUNC(u8, u8, "%u")
37 DEFINE_BASIC_PRINT_TYPE_FUNC(u16, u16, "%u")
38 DEFINE_BASIC_PRINT_TYPE_FUNC(u32, u32, "%u")
39 DEFINE_BASIC_PRINT_TYPE_FUNC(u64, u64, "%Lu")
40 DEFINE_BASIC_PRINT_TYPE_FUNC(s8, s8, "%d")
41 DEFINE_BASIC_PRINT_TYPE_FUNC(s16, s16, "%d")
42 DEFINE_BASIC_PRINT_TYPE_FUNC(s32, s32, "%d")
43 DEFINE_BASIC_PRINT_TYPE_FUNC(s64, s64, "%Ld")
44 DEFINE_BASIC_PRINT_TYPE_FUNC(x8, u8, "0x%x")
45 DEFINE_BASIC_PRINT_TYPE_FUNC(x16, u16, "0x%x")
46 DEFINE_BASIC_PRINT_TYPE_FUNC(x32, u32, "0x%x")
47 DEFINE_BASIC_PRINT_TYPE_FUNC(x64, u64, "0x%Lx")
49 int PRINT_TYPE_FUNC_NAME(symbol)(struct trace_seq *s, void *data, void *ent)
51 trace_seq_printf(s, "%pS", (void *)*(unsigned long *)data);
52 return !trace_seq_has_overflowed(s);
54 const char PRINT_TYPE_FMT_NAME(symbol)[] = "%pS";
56 /* Print type function for string type */
57 int PRINT_TYPE_FUNC_NAME(string)(struct trace_seq *s, void *data, void *ent)
59 int len = *(u32 *)data >> 16;
62 trace_seq_puts(s, "(fault)");
64 trace_seq_printf(s, "\"%s\"",
65 (const char *)get_loc_data(data, ent));
66 return !trace_seq_has_overflowed(s);
69 const char PRINT_TYPE_FMT_NAME(string)[] = "\\\"%s\\\"";
71 /* Fetch type information table */
72 static const struct fetch_type probe_fetch_types[] = {
74 __ASSIGN_FETCH_TYPE("string", string, string, sizeof(u32), 1,
77 ASSIGN_FETCH_TYPE(u8, u8, 0),
78 ASSIGN_FETCH_TYPE(u16, u16, 0),
79 ASSIGN_FETCH_TYPE(u32, u32, 0),
80 ASSIGN_FETCH_TYPE(u64, u64, 0),
81 ASSIGN_FETCH_TYPE(s8, u8, 1),
82 ASSIGN_FETCH_TYPE(s16, u16, 1),
83 ASSIGN_FETCH_TYPE(s32, u32, 1),
84 ASSIGN_FETCH_TYPE(s64, u64, 1),
85 ASSIGN_FETCH_TYPE_ALIAS(x8, u8, u8, 0),
86 ASSIGN_FETCH_TYPE_ALIAS(x16, u16, u16, 0),
87 ASSIGN_FETCH_TYPE_ALIAS(x32, u32, u32, 0),
88 ASSIGN_FETCH_TYPE_ALIAS(x64, u64, u64, 0),
89 ASSIGN_FETCH_TYPE_ALIAS(symbol, ADDR_FETCH_TYPE, ADDR_FETCH_TYPE, 0),
94 static const struct fetch_type *find_fetch_type(const char *type)
99 type = DEFAULT_FETCH_TYPE_STR;
101 /* Special case: bitfield */
105 type = strchr(type, '/');
110 if (kstrtoul(type, 0, &bs))
115 return find_fetch_type("u8");
117 return find_fetch_type("u16");
119 return find_fetch_type("u32");
121 return find_fetch_type("u64");
127 for (i = 0; probe_fetch_types[i].name; i++) {
128 if (strcmp(type, probe_fetch_types[i].name) == 0)
129 return &probe_fetch_types[i];
136 /* Split symbol and offset. */
137 int traceprobe_split_symbol_offset(char *symbol, long *offset)
145 tmp = strpbrk(symbol, "+-");
147 ret = kstrtol(tmp, 0, offset);
157 /* @buf must has MAX_EVENT_NAME_LEN size */
158 int traceprobe_parse_event_name(const char **pevent, const char **pgroup,
161 const char *slash, *event = *pevent;
164 slash = strchr(event, '/');
166 if (slash == event) {
167 pr_info("Group name is not specified\n");
170 if (slash - event + 1 > MAX_EVENT_NAME_LEN) {
171 pr_info("Group name is too long\n");
174 strlcpy(buf, event, slash - event + 1);
175 if (!is_good_name(buf)) {
176 pr_info("Group name must follow the same rules as C identifiers\n");
185 pr_info("Event name is not specified\n");
187 } else if (len > MAX_EVENT_NAME_LEN) {
188 pr_info("Event name is too long\n");
191 if (!is_good_name(event)) {
192 pr_info("Event name must follow the same rules as C identifiers\n");
198 #define PARAM_MAX_STACK (THREAD_SIZE / sizeof(unsigned long))
200 static int parse_probe_vars(char *arg, const struct fetch_type *t,
201 struct fetch_insn *code, unsigned int flags)
207 if (strcmp(arg, "retval") == 0) {
208 if (flags & TPARG_FL_RETURN)
209 code->op = FETCH_OP_RETVAL;
212 } else if ((len = str_has_prefix(arg, "stack"))) {
213 if (arg[len] == '\0') {
214 code->op = FETCH_OP_STACKP;
215 } else if (isdigit(arg[len])) {
216 ret = kstrtoul(arg + len, 10, ¶m);
217 if (ret || ((flags & TPARG_FL_KERNEL) &&
218 param > PARAM_MAX_STACK))
221 code->op = FETCH_OP_STACK;
222 code->param = (unsigned int)param;
226 } else if (strcmp(arg, "comm") == 0) {
227 code->op = FETCH_OP_COMM;
228 #ifdef CONFIG_HAVE_FUNCTION_ARG_ACCESS_API
229 } else if (((flags & TPARG_FL_MASK) ==
230 (TPARG_FL_KERNEL | TPARG_FL_FENTRY)) &&
231 (len = str_has_prefix(arg, "arg"))) {
232 if (!isdigit(arg[len]))
234 ret = kstrtoul(arg + len, 10, ¶m);
235 if (ret || !param || param > PARAM_MAX_STACK)
237 code->op = FETCH_OP_ARG;
238 code->param = (unsigned int)param - 1;
246 /* Recursive argument parser */
248 parse_probe_arg(char *arg, const struct fetch_type *type,
249 struct fetch_insn **pcode, struct fetch_insn *end,
252 struct fetch_insn *code = *pcode;
260 ret = parse_probe_vars(arg + 1, type, code, flags);
263 case '%': /* named register */
264 ret = regs_query_register_offset(arg + 1);
266 code->op = FETCH_OP_REG;
267 code->param = (unsigned int)ret;
272 case '@': /* memory, file-offset or symbol */
273 if (isdigit(arg[1])) {
274 ret = kstrtoul(arg + 1, 0, ¶m);
278 code->op = FETCH_OP_IMM;
279 code->immediate = param;
280 } else if (arg[1] == '+') {
281 /* kprobes don't support file offsets */
282 if (flags & TPARG_FL_KERNEL)
285 ret = kstrtol(arg + 2, 0, &offset);
289 code->op = FETCH_OP_FOFFS;
290 code->immediate = (unsigned long)offset; // imm64?
292 /* uprobes don't support symbols */
293 if (!(flags & TPARG_FL_KERNEL))
296 /* Preserve symbol for updating */
297 code->op = FETCH_NOP_SYMBOL;
298 code->data = kstrdup(arg + 1, GFP_KERNEL);
304 code->op = FETCH_OP_IMM;
307 /* These are fetching from memory */
311 code->op = FETCH_OP_DEREF;
312 code->offset = offset;
315 case '+': /* deref memory */
316 arg++; /* Skip '+', because kstrtol() rejects it. */
319 tmp = strchr(arg, '(');
324 ret = kstrtol(arg, 0, &offset);
329 tmp = strrchr(arg, ')');
332 const struct fetch_type *t2 = find_fetch_type(NULL);
335 ret = parse_probe_arg(arg, t2, &code, end, flags);
338 if (code->op == FETCH_OP_COMM)
344 code->op = FETCH_OP_DEREF;
345 code->offset = offset;
349 if (!ret && code->op == FETCH_OP_NOP) {
350 /* Parsed, but do not find fetch method */
356 #define BYTES_TO_BITS(nb) ((BITS_PER_LONG * (nb)) / sizeof(long))
358 /* Bitfield type needs to be parsed into a fetch function */
359 static int __parse_bitfield_probe_arg(const char *bf,
360 const struct fetch_type *t,
361 struct fetch_insn **pcode)
363 struct fetch_insn *code = *pcode;
364 unsigned long bw, bo;
370 bw = simple_strtoul(bf + 1, &tail, 0); /* Use simple one */
372 if (bw == 0 || *tail != '@')
376 bo = simple_strtoul(bf, &tail, 0);
378 if (tail == bf || *tail != '/')
381 if (code->op != FETCH_OP_NOP)
385 code->op = FETCH_OP_MOD_BF;
386 code->lshift = BYTES_TO_BITS(t->size) - (bw + bo);
387 code->rshift = BYTES_TO_BITS(t->size) - bw;
388 code->basesize = t->size;
390 return (BYTES_TO_BITS(t->size) < (bw + bo)) ? -EINVAL : 0;
393 /* String length checking wrapper */
394 static int traceprobe_parse_probe_arg_body(char *arg, ssize_t *size,
395 struct probe_arg *parg, unsigned int flags)
397 struct fetch_insn *code, *scode, *tmp = NULL;
401 if (strlen(arg) > MAX_ARGSTR_LEN) {
402 pr_info("Argument is too long.: %s\n", arg);
405 parg->comm = kstrdup(arg, GFP_KERNEL);
407 pr_info("Failed to allocate memory for command '%s'.\n", arg);
410 t = strchr(arg, ':');
413 t2 = strchr(++t, '[');
416 parg->count = simple_strtoul(t2 + 1, &t2, 0);
417 if (strcmp(t2, "]") || parg->count == 0)
419 if (parg->count > MAX_ARRAY_LEN)
424 * The default type of $comm should be "string", and it can't be
427 if (!t && strcmp(arg, "$comm") == 0)
428 parg->type = find_fetch_type("string");
430 parg->type = find_fetch_type(t);
432 pr_info("Unsupported type: %s\n", t);
435 parg->offset = *size;
436 *size += parg->type->size * (parg->count ?: 1);
439 len = strlen(parg->type->fmttype) + 6;
440 parg->fmt = kmalloc(len, GFP_KERNEL);
443 snprintf(parg->fmt, len, "%s[%d]", parg->type->fmttype,
447 code = tmp = kzalloc(sizeof(*code) * FETCH_INSN_MAX, GFP_KERNEL);
450 code[FETCH_INSN_MAX - 1].op = FETCH_OP_END;
452 ret = parse_probe_arg(arg, parg->type, &code, &code[FETCH_INSN_MAX - 1],
457 /* Store operation */
458 if (!strcmp(parg->type->name, "string")) {
459 if (code->op != FETCH_OP_DEREF && code->op != FETCH_OP_IMM &&
460 code->op != FETCH_OP_COMM) {
461 pr_info("string only accepts memory or address.\n");
465 if (code->op != FETCH_OP_DEREF || parg->count) {
467 * IMM and COMM is pointing actual address, those must
468 * be kept, and if parg->count != 0, this is an array
469 * of string pointers instead of string address itself.
472 if (code->op != FETCH_OP_NOP) {
477 code->op = FETCH_OP_ST_STRING; /* In DEREF case, replace it */
478 code->size = parg->type->size;
479 parg->dynamic = true;
480 } else if (code->op == FETCH_OP_DEREF) {
481 code->op = FETCH_OP_ST_MEM;
482 code->size = parg->type->size;
485 if (code->op != FETCH_OP_NOP) {
489 code->op = FETCH_OP_ST_RAW;
490 code->size = parg->type->size;
493 /* Modify operation */
495 ret = __parse_bitfield_probe_arg(t, parg->type, &code);
499 /* Loop(Array) operation */
501 if (scode->op != FETCH_OP_ST_MEM &&
502 scode->op != FETCH_OP_ST_STRING) {
503 pr_info("array only accepts memory or address\n");
508 if (code->op != FETCH_OP_NOP) {
512 code->op = FETCH_OP_LP_ARRAY;
513 code->param = parg->count;
516 code->op = FETCH_OP_END;
518 /* Shrink down the code buffer */
519 parg->code = kzalloc(sizeof(*code) * (code - tmp + 1), GFP_KERNEL);
523 memcpy(parg->code, tmp, sizeof(*code) * (code - tmp + 1));
527 for (code = tmp; code < tmp + FETCH_INSN_MAX; code++)
528 if (code->op == FETCH_NOP_SYMBOL)
536 /* Return 1 if name is reserved or already used by another argument */
537 static int traceprobe_conflict_field_name(const char *name,
538 struct probe_arg *args, int narg)
542 for (i = 0; i < ARRAY_SIZE(reserved_field_names); i++)
543 if (strcmp(reserved_field_names[i], name) == 0)
546 for (i = 0; i < narg; i++)
547 if (strcmp(args[i].name, name) == 0)
553 int traceprobe_parse_probe_arg(struct trace_probe *tp, int i, char *arg,
556 struct probe_arg *parg = &tp->args[i];
560 /* Increment count for freeing args in error case */
563 body = strchr(arg, '=');
565 if (body - arg > MAX_ARG_NAME_LEN || body == arg)
567 parg->name = kmemdup_nul(arg, body - arg, GFP_KERNEL);
570 /* If argument name is omitted, set "argN" */
571 parg->name = kasprintf(GFP_KERNEL, "arg%d", i + 1);
577 if (!is_good_name(parg->name)) {
578 pr_info("Invalid argument[%d] name: %s\n",
583 if (traceprobe_conflict_field_name(parg->name, tp->args, i)) {
584 pr_info("Argument[%d]: '%s' conflicts with another field.\n",
589 /* Parse fetch argument */
590 ret = traceprobe_parse_probe_arg_body(body, &tp->size, parg, flags);
592 pr_info("Parse error at argument[%d]. (%d)\n", i, ret);
596 void traceprobe_free_probe_arg(struct probe_arg *arg)
598 struct fetch_insn *code = arg->code;
600 while (code && code->op != FETCH_OP_END) {
601 if (code->op == FETCH_NOP_SYMBOL)
611 int traceprobe_update_arg(struct probe_arg *arg)
613 struct fetch_insn *code = arg->code;
619 while (code && code->op != FETCH_OP_END) {
620 if (code->op == FETCH_NOP_SYMBOL) {
621 if (code[1].op != FETCH_OP_IMM)
624 tmp = strpbrk(code->data, "+-");
627 ret = traceprobe_split_symbol_offset(code->data,
633 (unsigned long)kallsyms_lookup_name(code->data);
636 if (!code[1].immediate)
638 code[1].immediate += offset;
645 /* When len=0, we just calculate the needed length */
646 #define LEN_OR_ZERO (len ? len - pos : 0)
647 static int __set_print_fmt(struct trace_probe *tp, char *buf, int len,
650 struct probe_arg *parg;
653 const char *fmt, *arg;
657 arg = "REC->" FIELD_STRING_IP;
659 fmt = "(%lx <- %lx)";
660 arg = "REC->" FIELD_STRING_FUNC ", REC->" FIELD_STRING_RETIP;
663 pos += snprintf(buf + pos, LEN_OR_ZERO, "\"%s", fmt);
665 for (i = 0; i < tp->nr_args; i++) {
667 pos += snprintf(buf + pos, LEN_OR_ZERO, " %s=", parg->name);
669 pos += snprintf(buf + pos, LEN_OR_ZERO, "{%s",
671 for (j = 1; j < parg->count; j++)
672 pos += snprintf(buf + pos, LEN_OR_ZERO, ",%s",
674 pos += snprintf(buf + pos, LEN_OR_ZERO, "}");
676 pos += snprintf(buf + pos, LEN_OR_ZERO, "%s",
680 pos += snprintf(buf + pos, LEN_OR_ZERO, "\", %s", arg);
682 for (i = 0; i < tp->nr_args; i++) {
685 if (strcmp(parg->type->name, "string") == 0)
686 fmt = ", __get_str(%s[%d])";
688 fmt = ", REC->%s[%d]";
689 for (j = 0; j < parg->count; j++)
690 pos += snprintf(buf + pos, LEN_OR_ZERO,
693 if (strcmp(parg->type->name, "string") == 0)
694 fmt = ", __get_str(%s)";
697 pos += snprintf(buf + pos, LEN_OR_ZERO,
702 /* return the length of print_fmt */
707 int traceprobe_set_print_fmt(struct trace_probe *tp, bool is_return)
712 /* First: called with 0 length to calculate the needed length */
713 len = __set_print_fmt(tp, NULL, 0, is_return);
714 print_fmt = kmalloc(len + 1, GFP_KERNEL);
718 /* Second: actually write the @print_fmt */
719 __set_print_fmt(tp, print_fmt, len + 1, is_return);
720 tp->call.print_fmt = print_fmt;
725 int traceprobe_define_arg_fields(struct trace_event_call *event_call,
726 size_t offset, struct trace_probe *tp)
730 /* Set argument names as fields */
731 for (i = 0; i < tp->nr_args; i++) {
732 struct probe_arg *parg = &tp->args[i];
733 const char *fmt = parg->type->fmttype;
734 int size = parg->type->size;
740 ret = trace_define_field(event_call, fmt, parg->name,
741 offset + parg->offset, size,
742 parg->type->is_signed,