@@ -72,6 +72,7 @@ struct ddebug_iter {
struct flag_settings {
unsigned int flags;
unsigned int mask;
+ unsigned int trace_dst;
};
#define DD_OPEN_CMD "open"
@@ -84,11 +85,17 @@ struct dd_private_tracebuf {
int use_cnt;
};
+#define DST_NOT_SET (-1)
+
/*
- * Trace destination value 0 is reserved for writing
- * debug logs to trace events (prdbg, devdbg), that
- * is why buf[0] is not used and we traverse bitmap
- * starting from bit 1 (bit 0 is also not used).
+ * When trace is enabled (T flag is set) and trace destination field
+ * value is in range [1..63] then debug logs will be written to trace
+ * instance whose name is stored in buf[trace destination].name, e.g.
+ * when trace destination value is 2 and buf[2].name is set to tbt then
+ * debug logs will be written to <debugfs>/tracing/instances/tbt.
+ * On the other hand trace destination value 0 is reserved for writing
+ * debug logs to trace events (prdbg, devdbg), that is why buf[0] is not
+ * used and we traverse bitmap starting from bit 1 (bit 0 is also not used).
*/
struct dd_tracebuf_tbl_info {
struct dd_private_tracebuf buf[TRACE_DST_LAST];
@@ -126,6 +133,81 @@ static inline unsigned int get_trace_dst(const struct _ddebug *desc)
return desc->ctrl.trace_dst;
}
+static int find_tr_instance(const char *name)
+{
+ int idx = 1;
+
+ for_each_set_bit_from(idx, trc_tbl.bmap, trc_tbl.bmap_size)
+ if (!strcmp(trc_tbl.buf[idx].name, name))
+ return idx;
+
+ return -ENOENT;
+}
+
+static const
+char *read_colon_args(const char *str, struct flag_settings *modifiers)
+{
+ int len, idx = 0;
+ char *end;
+
+ /* Check if trace destination was already set */
+ if (modifiers->trace_dst != DST_NOT_SET)
+ return NULL;
+ /*
+ * When both T flag and ':' are provided then the T flag
+ * has to be followed by ':' in the form of 'T:'.
+ */
+ if (modifiers->flags & _DPRINTK_FLAGS_TRACE &&
+ *(str-1) != 'T')
+ return NULL;
+
+ if (strchr(str, 'T'))
+ return NULL;
+
+ str++;
+ end = strchr(str, '.');
+ if (end) {
+ len = end - str;
+ *end = '\0';
+ } else
+ len = strlen(str);
+ len -= 1;
+
+ /* destination trace events */
+ if (!strcmp(str, DD_TR_EVENT))
+ goto end;
+
+ idx = find_tr_instance(str);
+ if (idx < 0)
+ return NULL;
+end:
+ modifiers->trace_dst = idx;
+ return end ? end : str + len;
+}
+
+/*
+ * Maximum number of characters which are being displayed when
+ * printing trace instance name, longer names are truncated
+ */
+#define FLAG_COLON_ARG_LEN 24
+
+static char *show_colon_args(struct dd_ctrl *ctrl, char *p)
+{
+ int n, len = FLAG_COLON_ARG_LEN;
+ const char *str;
+
+ str = !ctrl->trace_dst ? DD_TR_EVENT :
+ trc_tbl.buf[ctrl->trace_dst].name;
+
+ n = snprintf(p, len, "%s", str);
+ if (n >= len) {
+ strscpy(&p[len-4], "...", 4);
+ n = len - 1;
+ }
+
+ return n < 0 ? p : p + n;
+}
+
/* Return the path relative to source root */
static inline const char *trim_prefix(const char *path)
{
@@ -137,9 +219,28 @@ static inline const char *trim_prefix(const char *path)
return path + skip;
}
-static const struct { unsigned flag:8; char opt_char; } opt_array[] = {
+typedef const char* (*read_flag_args_f)(const char *, struct flag_settings *);
+typedef char* (*show_flag_args_f)(struct dd_ctrl *, char *);
+
+static const struct
+{
+ unsigned flag:8;
+ char opt_char;
+ bool always_show;
+ read_flag_args_f read_args;
+ show_flag_args_f show_args;
+} opt_array[] = {
{ _DPRINTK_FLAGS_PRINTK, 'p' },
{ _DPRINTK_FLAGS_TRACE, 'T' },
+ /*
+ * We don't reserve a flag for ':'. The ':' is used to provide
+ * trace destination name and when provided together with T flag
+ * it enables output to the trace destination. When ':' is provided
+ * without T flag then it sets trace destination for a callsite for
+ * future use. When both T flag and ':'are provided together then
+ * ':' has to follow T flag in the form of 'T:'.
+ */
+ { _DPRINTK_FLAGS_NONE, ':', true, read_colon_args, show_colon_args },
{ _DPRINTK_FLAGS_INCL_MODNAME, 'm' },
{ _DPRINTK_FLAGS_INCL_FUNCNAME, 'f' },
{ _DPRINTK_FLAGS_INCL_SOURCENAME, 's' },
@@ -148,22 +249,31 @@ static const struct { unsigned flag:8; char opt_char; } opt_array[] = {
{ _DPRINTK_FLAGS_NONE, '_' },
};
-struct flagsbuf { char buf[ARRAY_SIZE(opt_array)+1]; };
+struct ctrlbuf { char buf[ARRAY_SIZE(opt_array)+FLAG_COLON_ARG_LEN+1]; };
/* format a string into buf[] which describes the _ddebug's flags */
-static char *ddebug_describe_flags(unsigned int flags, struct flagsbuf *fb)
+static char *ddebug_describe_ctrl(struct dd_ctrl *ctrl, struct ctrlbuf *cb)
{
- char *p = fb->buf;
+ show_flag_args_f show_args = NULL;
+ char *p = cb->buf;
int i;
for (i = 0; i < ARRAY_SIZE(opt_array); ++i)
- if (flags & opt_array[i].flag)
+ if (ctrl->flags & opt_array[i].flag ||
+ opt_array[i].always_show) {
+ if (show_args)
+ *p++ = '.';
*p++ = opt_array[i].opt_char;
- if (p == fb->buf)
+ show_args = opt_array[i].show_args;
+ if (show_args)
+ p = show_args(ctrl, p);
+ }
+
+ if (p == cb->buf)
*p++ = '_';
*p = '\0';
- return fb->buf;
+ return cb->buf;
}
#define vnpr_info(lvl, fmt, ...) \
@@ -221,17 +331,6 @@ static bool dd_good_trace_name(const char *str)
return true;
}
-static int find_tr_instance(const char *name)
-{
- int idx = 1;
-
- for_each_set_bit_from(idx, trc_tbl.bmap, trc_tbl.bmap_size)
- if (!strcmp(trc_tbl.buf[idx].name, name))
- return idx;
-
- return -ENOENT;
-}
-
static int handle_trace_open_cmd(const char *arg)
{
struct dd_private_tracebuf *buf;
@@ -383,7 +482,7 @@ static struct ddebug_class_map *ddebug_find_valid_class(struct ddebug_table cons
* Search the tables for _ddebug's which match the given `query' and
* apply the `flags' and `mask' to them. Returns number of matching
* callsites, normally the same as number of changes. If verbose,
- * logs the changes. Takes ddebug_lock.
+ * logs the changes.
*/
static int ddebug_change(const struct ddebug_query *query,
struct flag_settings *modifiers)
@@ -391,13 +490,12 @@ static int ddebug_change(const struct ddebug_query *query,
int i;
struct ddebug_table *dt;
unsigned int nfound = 0;
+ struct ctrlbuf cbuf, nbuf;
struct dd_ctrl nctrl = {0};
- struct flagsbuf fbuf, nbuf;
struct ddebug_class_map *map = NULL;
int __outvar valid_class;
/* search for matching ddebugs */
- mutex_lock(&ddebug_lock);
list_for_each_entry(dt, &ddebug_tables, link) {
/* match against the module name */
@@ -458,7 +556,8 @@ static int ddebug_change(const struct ddebug_query *query,
nfound++;
nctrl.flags = (get_flags(dp) & modifiers->mask) | modifiers->flags;
- if (!memcmp(&nctrl, get_ctrl(dp), sizeof(struct dd_ctrl)))
+ nctrl.trace_dst = modifiers->trace_dst;
+ if (!memcmp(&nctrl, get_ctrl(dp), sizeof(nctrl)))
continue;
#ifdef CONFIG_JUMP_LABEL
if (get_flags(dp) & _DPRINTK_FLAGS_ENABLED) {
@@ -471,13 +570,12 @@ static int ddebug_change(const struct ddebug_query *query,
v4pr_info("changed %s:%d [%s]%s %s => %s\n",
trim_prefix(dp->filename), dp->lineno,
dt->mod_name, dp->function,
- ddebug_describe_flags(get_flags(dp), &fbuf),
- ddebug_describe_flags(nctrl.flags, &nbuf));
+ ddebug_describe_ctrl(&dp->ctrl, &cbuf),
+ ddebug_describe_ctrl(&nctrl, &nbuf));
update_tr_dst(dp, &nctrl);
set_ctrl(dp, &nctrl);
}
}
- mutex_unlock(&ddebug_lock);
if (!nfound && verbose)
pr_info("no matches for query\n");
@@ -698,6 +796,7 @@ static int ddebug_parse_query(char *words[], int nwords,
*/
static int ddebug_parse_flags(const char *str, struct flag_settings *modifiers)
{
+ read_flag_args_f read_args;
int op, i;
switch (*str) {
@@ -716,6 +815,12 @@ static int ddebug_parse_flags(const char *str, struct flag_settings *modifiers)
for (i = ARRAY_SIZE(opt_array) - 1; i >= 0; i--) {
if (*str == opt_array[i].opt_char) {
modifiers->flags |= opt_array[i].flag;
+ read_args = opt_array[i].read_args;
+ if (read_args) {
+ str = read_args(str, modifiers);
+ if (!str)
+ return -EINVAL;
+ }
break;
}
}
@@ -724,7 +829,7 @@ static int ddebug_parse_flags(const char *str, struct flag_settings *modifiers)
return -EINVAL;
}
}
- v3pr_info("flags=0x%x\n", modifiers->flags);
+ v3pr_info("flags=0x%x, trace_dest=0x%x\n", modifiers->flags, modifiers->trace_dst);
/* calculate final flags, mask based upon op */
switch (op) {
@@ -747,7 +852,7 @@ static int ddebug_parse_flags(const char *str, struct flag_settings *modifiers)
static int ddebug_exec_query(char *query_string, const char *modname)
{
- struct flag_settings modifiers = {};
+ struct flag_settings modifiers = { .trace_dst = DST_NOT_SET };
struct ddebug_query query = {};
#define MAXWORDS 9
int nwords, nfound;
@@ -763,20 +868,38 @@ static int ddebug_exec_query(char *query_string, const char *modname)
if (is_dd_trace_cmd(words[0]))
return ddebug_parse_cmd(words, nwords-1);
- /* check flags 1st (last arg) so query is pairs of spec,val */
- if (ddebug_parse_flags(words[nwords-1], &modifiers)) {
- pr_err("flags parse failed\n");
- return -EINVAL;
- }
if (ddebug_parse_query(words, nwords-1, &query, modname)) {
pr_err("query parse failed\n");
return -EINVAL;
}
+
+ /*
+ * Both ddebug_parse_flags and ddebug_change have to be run
+ * with locking because ddebug_parse_flags->read_T_args verifies
+ * if a requested trace instance is opened. Next ddebug_change
+ * sets the requested trace instance as output for debug logs of
+ * callsite(s) which matched a query. Because ddebug_proc_write
+ * function can be called concurrently then without locking we
+ * could for example run into a scenario where ddebug_change uses
+ * a trace instance which is already closed.
+ */
+ mutex_lock(&ddebug_lock);
+
+ /* check flags 1st (last arg) so query is pairs of spec,val */
+ if (ddebug_parse_flags(words[nwords-1], &modifiers)) {
+ pr_err("flags parse failed\n");
+ goto err;
+ }
+
/* actually go and implement the change */
nfound = ddebug_change(&query, &modifiers);
- vpr_info_dq(&query, nfound ? "applied" : "no-match");
+ mutex_unlock(&ddebug_lock);
+ vpr_info_dq(&query, nfound ? "applied" : "no-match");
return nfound;
+err:
+ mutex_unlock(&ddebug_lock);
+ return -EINVAL;
}
/* handle multiple queries in query string, continue on error, return
@@ -1466,7 +1589,7 @@ static int ddebug_proc_show(struct seq_file *m, void *p)
{
struct ddebug_iter *iter = m->private;
struct _ddebug *dp = p;
- struct flagsbuf flags;
+ struct ctrlbuf cbuf;
char const *class;
if (p == SEQ_START_TOKEN) {
@@ -1478,7 +1601,7 @@ static int ddebug_proc_show(struct seq_file *m, void *p)
seq_printf(m, "%s:%u [%s]%s =%s \"",
trim_prefix(dp->filename), dp->lineno,
iter->table->mod_name, dp->function,
- ddebug_describe_flags(get_flags(dp), &flags));
+ ddebug_describe_ctrl(&dp->ctrl, &cbuf));
seq_escape_str(m, dp->format, ESCAPE_SPACE, "\t\r\n\"");
seq_puts(m, "\"");