tracing: Add hist trigger 'sym' and 'sym-offset' modifiers

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

Link: http://lkml.kernel.org/r/87d4935821491c0275513f0fbfb9bab8d3d3f079.1457029949.git.tom.zanussi@linux.intel.com
Signed-off-by: Tom Zanussi <tom.zanussi@linux.intel.com>
Tested-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Reviewed-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 2eb2eafbe7f54d0d984b48a8733baed5f8d53274..34459eb0c844013851c619b71a75e20eeb6f0e24 100644 (file)
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -3855,7 +3855,9 @@ static const char readme_msg[] =
        "\t    table in its entirety to stdout.  The default format used to\n"
        "\t    display a given field can be modified by appending any of the\n"
        "\t    following modifiers to the field name, as applicable:\n\n"
-       "\t            .hex        display a number as a hex value\n\n"
+       "\t            .hex        display a number as a hex value\n"
+       "\t            .sym        display an address as a symbol\n"
+       "\t            .sym-offset display an address as a symbol and offset\n\n"
        "\t    The 'pause' parameter can be used to pause an existing hist\n"
        "\t    trigger or to start a hist trigger but not log any events\n"
        "\t    until told to do so.  'continue' can be used to start or\n"

diff --git a/kernel/trace/trace_events_hist.c b/kernel/trace/trace_events_hist.c
index 8e49eeef8867c053864995263f0d66684230ed98..808cc06cdb615385dc8dbc900f4b3d632313e080 100644 (file)
--- a/kernel/trace/trace_events_hist.c
+++ b/kernel/trace/trace_events_hist.c
@@ -77,10 +77,12 @@ DEFINE_HIST_FIELD_FN(u8);
 #define HIST_KEY_SIZE_MAX      (MAX_FILTER_STR_VAL + sizeof(u64))
 
 enum hist_field_flags {
-       HIST_FIELD_FL_HITCOUNT  = 1,
-       HIST_FIELD_FL_KEY       = 2,
-       HIST_FIELD_FL_STRING    = 4,
-       HIST_FIELD_FL_HEX       = 8,
+       HIST_FIELD_FL_HITCOUNT          = 1,
+       HIST_FIELD_FL_KEY               = 2,
+       HIST_FIELD_FL_STRING            = 4,
+       HIST_FIELD_FL_HEX               = 8,
+       HIST_FIELD_FL_SYM               = 16,
+       HIST_FIELD_FL_SYM_OFFSET        = 32,
 };
 
 struct hist_trigger_attrs {
@@ -397,6 +399,10 @@ static int create_key_field(struct hist_trigger_data *hist_data,
        if (field_str) {
                if (strcmp(field_str, "hex") == 0)
                        flags |= HIST_FIELD_FL_HEX;
+               else if (strcmp(field_str, "sym") == 0)
+                       flags |= HIST_FIELD_FL_SYM;
+               else if (strcmp(field_str, "sym-offset") == 0)
+                       flags |= HIST_FIELD_FL_SYM_OFFSET;
                else {
                        ret = -EINVAL;
                        goto out;
@@ -726,6 +732,7 @@ 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;
 
@@ -741,6 +748,16 @@ 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_FL_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_FL_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_FL_STRING) {
                        seq_printf(m, "%s: %-50s", key_field->field->name,
                                   (char *)(key + key_field->offset));
@@ -856,6 +873,10 @@ static const char *get_hist_field_flags(struct hist_field *hist_field)
 
        if (hist_field->flags & HIST_FIELD_FL_HEX)
                flags_str = "hex";
+       else if (hist_field->flags & HIST_FIELD_FL_SYM)
+               flags_str = "sym";
+       else if (hist_field->flags & HIST_FIELD_FL_SYM_OFFSET)
+               flags_str = "sym-offset";
 
        return flags_str;
 }