1 files changed, 196 insertions, 54 deletions

diff --git a/tools/perf/util/probe-finder.c b/tools/perf/util/probe-finder.c
index c37fbef1711d..c470c49a804f 100644
--- a/tools/perf/util/probe-finder.c
+++ b/tools/perf/util/probe-finder.c
@@ -1,22 +1,8 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
 /*
  * probe-finder.c : C expression to kprobe event converter
  *
  * Written by Masami Hiramatsu <mhiramat@redhat.com>
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; either version 2 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, write to the Free Software
- * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
- *
  */
 
 #include <inttypes.h>
@@ -33,11 +19,12 @@
 #include <dwarf-regs.h>
 
 #include <linux/bitops.h>
+#include <linux/zalloc.h>
 #include "event.h"
 #include "dso.h"
 #include "debug.h"
 #include "intlist.h"
-#include "util.h"
+#include "strbuf.h"
 #include "strlist.h"
 #include "symbol.h"
 #include "probe-finder.h"
@@ -190,6 +177,17 @@ static int convert_variable_location(Dwarf_Die *vr_die, Dwarf_Addr addr,
 	if (dwarf_attr(vr_die, DW_AT_external, &attr) != NULL)
 		goto static_var;
 
+	/* Constant value */
+	if (dwarf_attr(vr_die, DW_AT_const_value, &attr) &&
+	    immediate_value_is_supported()) {
+		Dwarf_Sword snum;
+
+		dwarf_formsdata(&attr, &snum);
+		ret = asprintf(&tvar->value, "\\%ld", (long)snum);
+
+		return ret < 0 ? -ENOMEM : 0;
+	}
+
 	/* TODO: handle more than 1 exprs */
 	if (dwarf_attr(vr_die, DW_AT_location, &attr) == NULL)
 		return -EINVAL;	/* Broken DIE ? */
@@ -294,7 +292,7 @@ static_var:
 
 static int convert_variable_type(Dwarf_Die *vr_die,
 				 struct probe_trace_arg *tvar,
-				 const char *cast)
+				 const char *cast, bool user_access)
 {
 	struct probe_trace_arg_ref **ref_ptr = &tvar->ref;
 	Dwarf_Die type;
@@ -334,7 +332,8 @@ static int convert_variable_type(Dwarf_Die *vr_die,
 	pr_debug("%s type is %s.\n",
 		 dwarf_diename(vr_die), dwarf_diename(&type));
 
-	if (cast && strcmp(cast, "string") == 0) {	/* String type */
+	if (cast && (!strcmp(cast, "string") || !strcmp(cast, "ustring"))) {
+		/* String type */
 		ret = dwarf_tag(&type);
 		if (ret != DW_TAG_pointer_type &&
 		    ret != DW_TAG_array_type) {
@@ -357,6 +356,7 @@ static int convert_variable_type(Dwarf_Die *vr_die,
 				pr_warning("Out of memory error\n");
 				return -ENOMEM;
 			}
+			(*ref_ptr)->user_access = user_access;
 		}
 		if (!die_compare_name(&type, "char") &&
 		    !die_compare_name(&type, "unsigned char")) {
@@ -411,7 +411,7 @@ formatted:
 static int convert_variable_fields(Dwarf_Die *vr_die, const char *varname,
 				    struct perf_probe_arg_field *field,
 				    struct probe_trace_arg_ref **ref_ptr,
-				    Dwarf_Die *die_mem)
+				    Dwarf_Die *die_mem, bool user_access)
 {
 	struct probe_trace_arg_ref *ref = *ref_ptr;
 	Dwarf_Die type;
@@ -448,6 +448,7 @@ static int convert_variable_fields(Dwarf_Die *vr_die, const char *varname,
 				*ref_ptr = ref;
 		}
 		ref->offset += dwarf_bytesize(&type) * field->index;
+		ref->user_access = user_access;
 		goto next;
 	} else if (tag == DW_TAG_pointer_type) {
 		/* Check the pointer and dereference */
@@ -519,21 +520,30 @@ static int convert_variable_fields(Dwarf_Die *vr_die, const char *varname,
 		}
 	}
 	ref->offset += (long)offs;
+	ref->user_access = user_access;
 
 	/* If this member is unnamed, we need to reuse this field */
 	if (!dwarf_diename(die_mem))
 		return convert_variable_fields(die_mem, varname, field,
-						&ref, die_mem);
+						&ref, die_mem, user_access);
 
 next:
 	/* Converting next field */
 	if (field->next)
 		return convert_variable_fields(die_mem, field->name,
-					field->next, &ref, die_mem);
+				field->next, &ref, die_mem, user_access);
 	else
 		return 0;
 }
 
+static void print_var_not_found(const char *varname)
+{
+	pr_err("Failed to find the location of the '%s' variable at this address.\n"
+	       " Perhaps it has been optimized out.\n"
+	       " Use -V with the --range option to show '%s' location range.\n",
+		varname, varname);
+}
+
 /* Show a variables in kprobe event format */
 static int convert_variable(Dwarf_Die *vr_die, struct probe_finder *pf)
 {
@@ -545,21 +555,22 @@ static int convert_variable(Dwarf_Die *vr_die, struct probe_finder *pf)
 
 	ret = convert_variable_location(vr_die, pf->addr, pf->fb_ops,
 					&pf->sp_die, pf->machine, pf->tvar);
+	if (ret == -ENOENT && pf->skip_empty_arg)
+		/* This can be found in other place. skip it */
+		return 0;
 	if (ret == -ENOENT || ret == -EINVAL) {
-		pr_err("Failed to find the location of the '%s' variable at this address.\n"
-		       " Perhaps it has been optimized out.\n"
-		       " Use -V with the --range option to show '%s' location range.\n",
-		       pf->pvar->var, pf->pvar->var);
+		print_var_not_found(pf->pvar->var);
 	} else if (ret == -ENOTSUP)
 		pr_err("Sorry, we don't support this variable location yet.\n");
 	else if (ret == 0 && pf->pvar->field) {
 		ret = convert_variable_fields(vr_die, pf->pvar->var,
 					      pf->pvar->field, &pf->tvar->ref,
-					      &die_mem);
+					      &die_mem, pf->pvar->user_access);
 		vr_die = &die_mem;
 	}
 	if (ret == 0)
-		ret = convert_variable_type(vr_die, pf->tvar, pf->pvar->type);
+		ret = convert_variable_type(vr_die, pf->tvar, pf->pvar->type,
+					    pf->pvar->user_access);
 	/* *expr will be cached in libdw. Don't free it. */
 	return ret;
 }
@@ -595,6 +606,8 @@ static int find_variable(Dwarf_Die *sc_die, struct probe_finder *pf)
 		/* Search again in global variables */
 		if (!die_find_variable_at(&pf->cu_die, pf->pvar->var,
 						0, &vr_die)) {
+			if (pf->skip_empty_arg)
+				return 0;
 			pr_warning("Failed to find '%s' in this function.\n",
 				   pf->pvar->var);
 			ret = -ENOENT;
@@ -612,38 +625,26 @@ static int convert_to_trace_point(Dwarf_Die *sp_die, Dwfl_Module *mod,
 				  const char *function,
 				  struct probe_trace_point *tp)
 {
-	Dwarf_Addr eaddr, highaddr;
+	Dwarf_Addr eaddr;
 	GElf_Sym sym;
 	const char *symbol;
 
 	/* Verify the address is correct */
-	if (dwarf_entrypc(sp_die, &eaddr) != 0) {
-		pr_warning("Failed to get entry address of %s\n",
-			   dwarf_diename(sp_die));
-		return -ENOENT;
-	}
-	if (dwarf_highpc(sp_die, &highaddr) != 0) {
-		pr_warning("Failed to get end address of %s\n",
-			   dwarf_diename(sp_die));
-		return -ENOENT;
-	}
-	if (paddr > highaddr) {
-		pr_warning("Offset specified is greater than size of %s\n",
+	if (!dwarf_haspc(sp_die, paddr)) {
+		pr_warning("Specified offset is out of %s\n",
 			   dwarf_diename(sp_die));
 		return -EINVAL;
 	}
 
-	symbol = dwarf_diename(sp_die);
+	/* Try to get actual symbol name from symtab */
+	symbol = dwfl_module_addrsym(mod, paddr, &sym, NULL);
 	if (!symbol) {
-		/* Try to get the symbol name from symtab */
-		symbol = dwfl_module_addrsym(mod, paddr, &sym, NULL);
-		if (!symbol) {
-			pr_warning("Failed to find symbol at 0x%lx\n",
-				   (unsigned long)paddr);
-			return -ENOENT;
-		}
-		eaddr = sym.st_value;
+		pr_warning("Failed to find symbol at 0x%lx\n",
+			   (unsigned long)paddr);
+		return -ENOENT;
 	}
+	eaddr = sym.st_value;
+
 	tp->offset = (unsigned long)(paddr - eaddr);
 	tp->address = (unsigned long)paddr;
 	tp->symbol = strdup(symbol);
@@ -764,6 +765,16 @@ static int find_best_scope_cb(Dwarf_Die *fn_die, void *data)
 	return 0;
 }
 
+/* Return innermost DIE */
+static int find_inner_scope_cb(Dwarf_Die *fn_die, void *data)
+{
+	struct find_scope_param *fsp = data;
+
+	memcpy(fsp->die_mem, fn_die, sizeof(Dwarf_Die));
+	fsp->found = true;
+	return 1;
+}
+
 /* Find an appropriate scope fits to given conditions */
 static Dwarf_Die *find_best_scope(struct probe_finder *pf, Dwarf_Die *die_mem)
 {
@@ -775,12 +786,50 @@ static Dwarf_Die *find_best_scope(struct probe_finder *pf, Dwarf_Die *die_mem)
 		.die_mem = die_mem,
 		.found = false,
 	};
+	int ret;
 
-	cu_walk_functions_at(&pf->cu_die, pf->addr, find_best_scope_cb, &fsp);
+	ret = cu_walk_functions_at(&pf->cu_die, pf->addr, find_best_scope_cb,
+				   &fsp);
+	if (!ret && !fsp.found)
+		cu_walk_functions_at(&pf->cu_die, pf->addr,
+				     find_inner_scope_cb, &fsp);
 
 	return fsp.found ? die_mem : NULL;
 }
 
+static int verify_representive_line(struct probe_finder *pf, const char *fname,
+				int lineno, Dwarf_Addr addr)
+{
+	const char *__fname, *__func = NULL;
+	Dwarf_Die die_mem;
+	int __lineno;
+
+	/* Verify line number and address by reverse search */
+	if (cu_find_lineinfo(&pf->cu_die, addr, &__fname, &__lineno) < 0)
+		return 0;
+
+	pr_debug2("Reversed line: %s:%d\n", __fname, __lineno);
+	if (strcmp(fname, __fname) || lineno == __lineno)
+		return 0;
+
+	pr_warning("This line is sharing the address with other lines.\n");
+
+	if (pf->pev->point.function) {
+		/* Find best match function name and lines */
+		pf->addr = addr;
+		if (find_best_scope(pf, &die_mem)
+		    && die_match_name(&die_mem, pf->pev->point.function)
+		    && dwarf_decl_line(&die_mem, &lineno) == 0) {
+			__func = dwarf_diename(&die_mem);
+			__lineno -= lineno;
+		}
+	}
+	pr_warning("Please try to probe at %s:%d instead.\n",
+		   __func ? : __fname, __lineno);
+
+	return -ENOENT;
+}
+
 static int probe_point_line_walker(const char *fname, int lineno,
 				   Dwarf_Addr addr, void *data)
 {
@@ -791,6 +840,9 @@ static int probe_point_line_walker(const char *fname, int lineno,
 	if (lineno != pf->lno || strtailcmp(fname, pf->fname) != 0)
 		return 0;
 
+	if (verify_representive_line(pf, fname, lineno, addr))
+		return -ENOENT;
+
 	pf->addr = addr;
 	sc_die = find_best_scope(pf, &die_mem);
 	if (!sc_die) {
@@ -950,7 +1002,7 @@ static int probe_point_inline_cb(Dwarf_Die *in_die, void *data)
 		ret = find_probe_point_lazy(in_die, pf);
 	else {
 		/* Get probe address */
-		if (dwarf_entrypc(in_die, &addr) != 0) {
+		if (die_entrypc(in_die, &addr) != 0) {
 			pr_warning("Failed to get entry address of %s.\n",
 				   dwarf_diename(in_die));
 			return -ENOENT;
@@ -1002,7 +1054,7 @@ static int probe_point_search_cb(Dwarf_Die *sp_die, void *data)
 		param->retval = find_probe_point_by_line(pf);
 	} else if (die_is_func_instance(sp_die)) {
 		/* Instances always have the entry address */
-		dwarf_entrypc(sp_die, &pf->addr);
+		die_entrypc(sp_die, &pf->addr);
 		/* But in some case the entry address is 0 */
 		if (pf->addr == 0) {
 			pr_debug("%s has no entry PC. Skipped\n",
@@ -1253,6 +1305,17 @@ static int expand_probe_args(Dwarf_Die *sc_die, struct probe_finder *pf,
 	return n;
 }
 
+static bool trace_event_finder_overlap(struct trace_event_finder *tf)
+{
+	int i;
+
+	for (i = 0; i < tf->ntevs; i++) {
+		if (tf->pf.addr == tf->tevs[i].point.address)
+			return true;
+	}
+	return false;
+}
+
 /* Add a found probe point into trace event list */
 static int add_probe_trace_event(Dwarf_Die *sc_die, struct probe_finder *pf)
 {
@@ -1263,6 +1326,14 @@ static int add_probe_trace_event(Dwarf_Die *sc_die, struct probe_finder *pf)
 	struct perf_probe_arg *args = NULL;
 	int ret, i;
 
+	/*
+	 * For some reason (e.g. different column assigned to same address)
+	 * This callback can be called with the address which already passed.
+	 * Ignore it first.
+	 */
+	if (trace_event_finder_overlap(tf))
+		return 0;
+
 	/* Check number of tevs */
 	if (tf->ntevs == tf->max_tevs) {
 		pr_warning("Too many( > %d) probe point found.\n",
@@ -1323,6 +1394,44 @@ end:
 	return ret;
 }
 
+static int fill_empty_trace_arg(struct perf_probe_event *pev,
+				struct probe_trace_event *tevs, int ntevs)
+{
+	char **valp;
+	char *type;
+	int i, j, ret;
+
+	for (i = 0; i < pev->nargs; i++) {
+		type = NULL;
+		for (j = 0; j < ntevs; j++) {
+			if (tevs[j].args[i].value) {
+				type = tevs[j].args[i].type;
+				break;
+			}
+		}
+		if (j == ntevs) {
+			print_var_not_found(pev->args[i].var);
+			return -ENOENT;
+		}
+		for (j = 0; j < ntevs; j++) {
+			valp = &tevs[j].args[i].value;
+			if (*valp)
+				continue;
+
+			ret = asprintf(valp, "\\%lx", probe_conf.magic_num);
+			if (ret < 0)
+				return -ENOMEM;
+			/* Note that type can be NULL */
+			if (type) {
+				tevs[j].args[i].type = strdup(type);
+				if (!tevs[j].args[i].type)
+					return -ENOMEM;
+			}
+		}
+	}
+	return 0;
+}
+
 /* Find probe_trace_events specified by perf_probe_event from debuginfo */
 int debuginfo__find_trace_events(struct debuginfo *dbg,
 				 struct perf_probe_event *pev,
@@ -1341,7 +1450,13 @@ int debuginfo__find_trace_events(struct debuginfo *dbg,
 	tf.tevs = *tevs;
 	tf.ntevs = 0;
 
+	if (pev->nargs != 0 && immediate_value_is_supported())
+		tf.pf.skip_empty_arg = true;
+
 	ret = debuginfo__find_probes(dbg, &tf.pf);
+	if (ret >= 0 && tf.pf.skip_empty_arg)
+		ret = fill_empty_trace_arg(pev, tf.tevs, tf.ntevs);
+
 	if (ret < 0) {
 		for (i = 0; i < tf.ntevs; i++)
 			clear_probe_trace_event(&tf.tevs[i]);
@@ -1414,6 +1529,18 @@ error:
 	return DIE_FIND_CB_END;
 }
 
+static bool available_var_finder_overlap(struct available_var_finder *af)
+{
+	int i;
+
+	for (i = 0; i < af->nvls; i++) {
+		if (af->pf.addr == af->vls[i].point.address)
+			return true;
+	}
+	return false;
+
+}
+
 /* Add a found vars into available variables list */
 static int add_available_vars(Dwarf_Die *sc_die, struct probe_finder *pf)
 {
@@ -1424,6 +1551,14 @@ static int add_available_vars(Dwarf_Die *sc_die, struct probe_finder *pf)
 	Dwarf_Die die_mem;
 	int ret;
 
+	/*
+	 * For some reason (e.g. different column assigned to same address),
+	 * this callback can be called with the address which already passed.
+	 * Ignore it first.
+	 */
+	if (available_var_finder_overlap(af))
+		return 0;
+
 	/* Check number of tevs */
 	if (af->nvls == af->max_vls) {
 		pr_warning("Too many( > %d) probe point found.\n", af->max_vls);
@@ -1567,7 +1702,7 @@ int debuginfo__find_probe_point(struct debuginfo *dbg, unsigned long addr,
 		/* Get function entry information */
 		func = basefunc = dwarf_diename(&spdie);
 		if (!func ||
-		    dwarf_entrypc(&spdie, &baseaddr) != 0 ||
+		    die_entrypc(&spdie, &baseaddr) != 0 ||
 		    dwarf_decl_line(&spdie, &baseline) != 0) {
 			lineno = 0;
 			goto post;
@@ -1584,7 +1719,7 @@ int debuginfo__find_probe_point(struct debuginfo *dbg, unsigned long addr,
 		while (die_find_top_inlinefunc(&spdie, (Dwarf_Addr)addr,
 						&indie)) {
 			/* There is an inline function */
-			if (dwarf_entrypc(&indie, &_addr) == 0 &&
+			if (die_entrypc(&indie, &_addr) == 0 &&
 			    _addr == addr) {
 				/*
 				 * addr is at an inline function entry.
@@ -1664,12 +1799,19 @@ static int line_range_walk_cb(const char *fname, int lineno,
 			      void *data)
 {
 	struct line_finder *lf = data;
+	const char *__fname;
+	int __lineno;
 	int err;
 
 	if ((strtailcmp(fname, lf->fname) != 0) ||
 	    (lf->lno_s > lineno || lf->lno_e < lineno))
 		return 0;
 
+	/* Make sure this line can be reversable */
+	if (cu_find_lineinfo(&lf->cu_die, addr, &__fname, &__lineno) > 0
+	    && (lineno != __lineno || strcmp(fname, __fname)))
+		return 0;
+
 	err = line_range_add_line(fname, lineno, lf->lr);
 	if (err < 0 && err != -EEXIST)
 		return err;