[PATCH v8 15/23] tracing: Add hist trigger 'sym' and 'sym-offset' modifiers

[Tom Zanussi]

Allow users to have address fields displayed as symbols in the output
by appending '.sym' or 'sym-offset' to field names:

   # echo hist:keys=aaa.sym,bbb.sym-offset ... \
              [ if filter] > event/trigger

Signed-off-by: Tom Zanussi <tom.zanussi@xxxxxxxxxxxxxxx>
---
 kernel/trace/trace.c             |  2 ++
 kernel/trace/trace_events_hist.c | 21 +++++++++++++++++++++
 2 files changed, 23 insertions(+)

diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 14f9472..8cdc7b3 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -3814,6 +3814,8 @@ static const char readme_msg[] =
 	"\t    integers.  This can be modified by appending any of the\n"
 	"\t    following modifiers to the field name:\n\n"
 	"\t            .hex        display a number as a hex value\n\n"
+	"\t            .sym        display an address as a symbol\n"
+	"\t            .sym-offset display an address as a symbol and offset\n"
 	"\t    By default, the size of the hash table is 2048 entries.  The\n"
 	"\t    'size' param can be used to specify more or fewer than that.\n"
 	"\t    The units are in terms of hashtable entries - if a run uses\n"
diff --git a/kernel/trace/trace_events_hist.c b/kernel/trace/trace_events_hist.c
index 9cc38ee..106d557 100644
--- a/kernel/trace/trace_events_hist.c
+++ b/kernel/trace/trace_events_hist.c
@@ -73,6 +73,8 @@ enum hist_field_flags {
 	HIST_FIELD_KEY		= 2,
 	HIST_FIELD_STRING	= 4,
 	HIST_FIELD_HEX		= 8,
+	HIST_FIELD_SYM		= 16,
+	HIST_FIELD_SYM_OFFSET	= 32,
 };
 
 struct hist_trigger_attrs {
@@ -370,6 +372,10 @@ static int create_key_field(struct hist_trigger_data *hist_data,
 	if (field_str) {
 		if (!strcmp(field_str, "hex"))
 			flags |= HIST_FIELD_HEX;
+		else if (!strcmp(field_str, "sym"))
+			flags |= HIST_FIELD_SYM;
+		else if (!strcmp(field_str, "sym-offset"))
+			flags |= HIST_FIELD_SYM_OFFSET;
 		else {
 			ret = -EINVAL;
 			goto out;
@@ -700,6 +706,7 @@ hist_trigger_entry_print(struct seq_file *m,
 			 struct tracing_map_elt *elt)
 {
 	struct hist_field *key_field;
+	char str[KSYM_SYMBOL_LEN];
 	unsigned int i;
 	u64 uval;
 
@@ -715,6 +722,16 @@ hist_trigger_entry_print(struct seq_file *m,
 			uval = *(u64 *)(key + key_field->offset);
 			seq_printf(m, "%s: %llx",
 				   key_field->field->name, uval);
+		} else if (key_field->flags & HIST_FIELD_SYM) {
+			uval = *(u64 *)(key + key_field->offset);
+			sprint_symbol_no_offset(str, uval);
+			seq_printf(m, "%s: [%llx] %-45s",
+				   key_field->field->name, uval, str);
+		} else if (key_field->flags & HIST_FIELD_SYM_OFFSET) {
+			uval = *(u64 *)(key + key_field->offset);
+			sprint_symbol(str, uval);
+			seq_printf(m, "%s: [%llx] %-55s",
+				   key_field->field->name, uval, str);
 		} else if (key_field->flags & HIST_FIELD_STRING) {
 			seq_printf(m, "%s: %-35s", key_field->field->name,
 				   (char *)(key + key_field->offset));
@@ -824,6 +841,10 @@ static const char *get_hist_field_flags(struct hist_field *hist_field)
 
 	if (hist_field->flags & HIST_FIELD_HEX)
 		flags_str = "hex";
+	else if (hist_field->flags & HIST_FIELD_SYM)
+		flags_str = "sym";
+	else if (hist_field->flags & HIST_FIELD_SYM_OFFSET)
+		flags_str = "sym-offset";
 
 	return flags_str;
 }
-- 
1.9.3

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