5 files changed, 33 insertions, 7 deletions

diff --git a/tools/perf/util/probe-event.c b/tools/perf/util/probe-event.c
index 0c3b55d0617d..cd1eb73cfe83 100644
--- a/tools/perf/util/probe-event.c
+++ b/tools/perf/util/probe-event.c
@@ -1562,6 +1562,17 @@ static int parse_perf_probe_arg(char *str, struct perf_probe_arg *arg)
 		str = tmp + 1;
 	}
 
+	tmp = strchr(str, '@');
+	if (tmp && tmp != str && strcmp(tmp + 1, "user")) { /* user attr */
+		if (!user_access_is_supported()) {
+			semantic_error("ftrace does not support user access\n");
+			return -EINVAL;
+		}
+		*tmp = '\0';
+		arg->user_access = true;
+		pr_debug("user_access ");
+	}
+
 	tmp = strchr(str, ':');
 	if (tmp) {	/* Type setting */
 		*tmp = '\0';
diff --git a/tools/perf/util/probe-event.h b/tools/perf/util/probe-event.h
index 05c8d571a901..96a319cd2378 100644
--- a/tools/perf/util/probe-event.h
+++ b/tools/perf/util/probe-event.h
@@ -37,6 +37,7 @@ struct probe_trace_point {
 struct probe_trace_arg_ref {
 	struct probe_trace_arg_ref	*next;	/* Next reference */
 	long				offset;	/* Offset value */
+	bool				user_access;	/* User-memory access */
 };
 
 /* kprobe-tracer and uprobe-tracer tracing argument */
@@ -82,6 +83,7 @@ struct perf_probe_arg {
 	char				*var;	/* Variable name */
 	char				*type;	/* Type name */
 	struct perf_probe_arg_field	*field;	/* Structure fields */
+	bool				user_access;	/* User-memory access */
 };
 
 /* Perf probe probing event (point + arg) */
diff --git a/tools/perf/util/probe-file.c b/tools/perf/util/probe-file.c
index c2998f90b23c..5b4d49382932 100644
--- a/tools/perf/util/probe-file.c
+++ b/tools/perf/util/probe-file.c
@@ -1005,6 +1005,7 @@ enum ftrace_readme {
 	FTRACE_README_PROBE_TYPE_X = 0,
 	FTRACE_README_KRETPROBE_OFFSET,
 	FTRACE_README_UPROBE_REF_CTR,
+	FTRACE_README_USER_ACCESS,
 	FTRACE_README_END,
 };
 
@@ -1017,6 +1018,7 @@ static struct {
 	DEFINE_TYPE(FTRACE_README_PROBE_TYPE_X, "*type: * x8/16/32/64,*"),
 	DEFINE_TYPE(FTRACE_README_KRETPROBE_OFFSET, "*place (kretprobe): *"),
 	DEFINE_TYPE(FTRACE_README_UPROBE_REF_CTR, "*ref_ctr_offset*"),
+	DEFINE_TYPE(FTRACE_README_USER_ACCESS, "*[u]<offset>*"),
 };
 
 static bool scan_ftrace_readme(enum ftrace_readme type)
@@ -1077,3 +1079,8 @@ bool uprobe_ref_ctr_is_supported(void)
 {
 	return scan_ftrace_readme(FTRACE_README_UPROBE_REF_CTR);
 }
+
+bool user_access_is_supported(void)
+{
+	return scan_ftrace_readme(FTRACE_README_USER_ACCESS);
+}
diff --git a/tools/perf/util/probe-file.h b/tools/perf/util/probe-file.h
index 2a249182f2a6..986c1c94f64f 100644
--- a/tools/perf/util/probe-file.h
+++ b/tools/perf/util/probe-file.h
@@ -70,6 +70,7 @@ int probe_cache__show_all_caches(struct strfilter *filter);
 bool probe_type_is_available(enum probe_type type);
 bool kretprobe_offset_is_supported(void);
 bool uprobe_ref_ctr_is_supported(void);
+bool user_access_is_supported(void);
 #else	/* ! HAVE_LIBELF_SUPPORT */
 static inline struct probe_cache *probe_cache__new(const char *tgt __maybe_unused, struct nsinfo *nsi __maybe_unused)
 {
diff --git a/tools/perf/util/probe-finder.c b/tools/perf/util/probe-finder.c
index 7d8c99734928..025fc4491993 100644
--- a/tools/perf/util/probe-finder.c
+++ b/tools/perf/util/probe-finder.c
@@ -280,7 +280,7 @@ 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;
@@ -320,7 +320,8 @@ 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) {
@@ -343,6 +344,7 @@ 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")) {
@@ -397,7 +399,7 @@ 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;
@@ -434,6 +436,7 @@ 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 */
@@ -505,17 +508,18 @@ 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;
 }
@@ -541,11 +545,12 @@ static int convert_variable(Dwarf_Die *vr_die, struct probe_finder *pf)
 	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;
 }