[PATCH v11 06/19] dyndbg: add class_id to callsites

Jim Cromie
2022-01-07T05:30:06Z

DRM defines/uses a 10 enum drm_debug_category to create exclusive
classes of debug messages. To support this directly in dynamic-debug,
add the following:

- struct _ddebug.class_id 4 bits is enough for drm_debug_category

and the query support:

- struct _ddebug_query.class_id
- ddebug_change - looks for "class" keyword
- parse_class - accepts uint: 1-15, sets query->class_id
- vpr_info_dq - displays new field
- ddebug_proc_show - append column with "cls:%d"

With this patch, the following cmd is accepted w/o error:

#> echo module drm class 2 +p > /proc/dynamic_debug/control

It currently does nothing, since no pr_debug callsites can yet be
initialized with class_id != 0.

Note that this is specifically an error:

#> echo module drm class 0 +p > /proc/dynamic_debug/control

parse_class() prohibits this, we reserve "class 0" as a non-category.
This means that all good inputs are true, and 0 is special.

NOTES:

Patch extends DEFINE_DYNAMIC_DEBUG_METADATA() with a _CLS suffix, and
a new cls param, and re-adds old name using extended name. Then,
repeats those mods up through the Factory macros that use the
METADATA* .data constructors, so as to actually supply the category
into the initializer.

CC: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
---
.../admin-guide/dynamic-debug-howto.rst | 11 +++++
include/linux/dynamic_debug.h | 41 +++++++++++++------
lib/dynamic_debug.c | 30 ++++++++++++--
3 files changed, 67 insertions(+), 15 deletions(-)

diff --git a/Documentation/admin-guide/dynamic-debug-howto.rst b/Documentation/admin-guide/dynamic-debug-howto.rst
index 3c8f104a143f..7e1322660b10 100644
--- a/Documentation/admin-guide/dynamic-debug-howto.rst
+++ b/Documentation/admin-guide/dynamic-debug-howto.rst
@@ -35,6 +35,7 @@ Dynamic debug has even more useful features:
- line number (including ranges of line numbers)
- module name
- format string
+ - class number:1-15

* Provides a debugfs control file: ``<debugfs>/dynamic_debug/control``
which can be read to display the complete list of known debug
@@ -143,6 +144,7 @@ against. Possible keywords are:::
'module' string |
'format' string |
'line' line-range
+ 'class' integer:[1-15]

line-range ::= lineno |
'-'lineno |
@@ -217,6 +219,15 @@ line
line -1605 // the 1605 lines from line 1 to line 1605
line 1600- // all lines from line 1600 to the end of the file

+class
+ This expects a single integer, in range: 1-15.
+ Using this specification constrains to exact class_id matches.
+ This is intended for DRM.debug enumerated categories, plus 1.
+ class_id = 0 is reserved, returns an error currently.
+
+ This differs from the others primarily in that it is not displayed
+ in the control file currently, add later as an extra column.
+
The flags specification comprises a change operation followed
by one or more flag characters. The change operation is one
of the characters::
diff --git a/include/linux/dynamic_debug.h b/include/linux/dynamic_debug.h
index e0c2d7c0938b..e9483cd9ac1c 100644
--- a/include/linux/dynamic_debug.h
+++ b/include/linux/dynamic_debug.h
@@ -20,6 +20,7 @@ struct _ddebug {
const char *function;
const char *filename;
const char *format;
+ unsigned int class_id:4;
unsigned int lineno:18;
/*
* The flags field controls the behaviour at the callsite.
@@ -91,7 +92,7 @@ void __dynamic_ibdev_dbg(struct _ddebug *descriptor,
const struct ib_device *ibdev,
const char *fmt, ...);

-#define DEFINE_DYNAMIC_DEBUG_METADATA(name, fmt) \
+#define DEFINE_DYNAMIC_DEBUG_METADATA_CLS(name, cls, fmt) \
static struct _ddebug __aligned(8) \
__section("__dyndbg") name = { \
.modname = KBUILD_MODNAME, \
@@ -100,9 +101,13 @@ void __dynamic_ibdev_dbg(struct _ddebug *descriptor,
.format = (fmt), \
.lineno = __LINE__, \
.flags = _DPRINTK_FLAGS_DEFAULT, \
+ .class_id = cls, \
_DPRINTK_KEY_INIT \
}

+#define DEFINE_DYNAMIC_DEBUG_METADATA(name, fmt) \
+ DEFINE_DYNAMIC_DEBUG_METADATA_CLS(name, 0, fmt)
+
#ifdef CONFIG_JUMP_LABEL

#ifdef DEBUG
@@ -132,17 +137,21 @@ void __dynamic_ibdev_dbg(struct _ddebug *descriptor,

#endif /* CONFIG_JUMP_LABEL */

-#define __dynamic_func_call(id, fmt, func, ...) do { \
- DEFINE_DYNAMIC_DEBUG_METADATA(id, fmt); \
- if (DYNAMIC_DEBUG_BRANCH(id)) \
- func(&id, ##__VA_ARGS__); \
+#define __dynamic_func_call_cls(id, cls, fmt, func, ...) do { \
+ DEFINE_DYNAMIC_DEBUG_METADATA_CLS(id, cls, fmt); \
+ if (DYNAMIC_DEBUG_BRANCH(id)) \
+ func(&id, ##__VA_ARGS__); \
} while (0)
+#define __dynamic_func_call(id, fmt, func, ...) \
+ __dynamic_func_call_cls(id, 0, fmt, func, ##__VA_ARGS__)

-#define __dynamic_func_call_no_desc(id, fmt, func, ...) do { \
- DEFINE_DYNAMIC_DEBUG_METADATA(id, fmt); \
- if (DYNAMIC_DEBUG_BRANCH(id)) \
- func(__VA_ARGS__); \
+#define __dynamic_func_call_no_desc_cls(id, cls, fmt, func, ...) do { \
+ DEFINE_DYNAMIC_DEBUG_METADATA_CLS(id, cls, fmt); \
+ if (DYNAMIC_DEBUG_BRANCH(id)) \
+ func(__VA_ARGS__); \
} while (0)
+#define __dynamic_func_call_no_desc(id, fmt, func, ...) \
+ __dynamic_func_call_no_desc_cls(id, 0, fmt, func, ##__VA_ARGS__)

/*
* "Factory macro" for generating a call to func, guarded by a
@@ -152,15 +161,23 @@ void __dynamic_ibdev_dbg(struct _ddebug *descriptor,
* the varargs. Note that fmt is repeated in invocations of this
* macro.
*/
+#define _dynamic_func_call_cls(cls, fmt, func, ...) \
+ __dynamic_func_call_cls(__UNIQUE_ID(ddebug), cls, fmt, func, ##__VA_ARGS__)
#define _dynamic_func_call(fmt, func, ...) \
- __dynamic_func_call(__UNIQUE_ID(ddebug), fmt, func, ##__VA_ARGS__)
+ __dynamic_func_call_cls(__UNIQUE_ID(ddebug), 0, fmt, func, ##__VA_ARGS__)
+
/*
* A variant that does the same, except that the descriptor is not
* passed as the first argument to the function; it is only called
* with precisely the macro's varargs.
*/
-#define _dynamic_func_call_no_desc(fmt, func, ...) \
- __dynamic_func_call_no_desc(__UNIQUE_ID(ddebug), fmt, func, ##__VA_ARGS__)
+#define _dynamic_func_call_no_desc_cls(fmt, eCat, func, ...) \
+ __dynamic_func_call_no_desc_cls(__UNIQUE_ID(ddebug), eCat, \
+ fmt, func, ##__VA_ARGS__)
+
+#define _dynamic_func_call_no_desc(fmt, func, ...) \
+ __dynamic_func_call_no_desc_cls(__UNIQUE_ID(ddebug), 0, \
+ fmt, func, ##__VA_ARGS__)

#define dynamic_pr_debug(fmt, ...) \
_dynamic_func_call(fmt, __dynamic_pr_debug, \
diff --git a/lib/dynamic_debug.c b/lib/dynamic_debug.c
index 2efdc4f1553f..419d4664e724 100644
--- a/lib/dynamic_debug.c
+++ b/lib/dynamic_debug.c
@@ -58,6 +58,7 @@ struct ddebug_query {
const char *function;
const char *format;
unsigned int first_lineno, last_lineno;
+ unsigned int class_id;
};

struct ddebug_iter {
@@ -138,13 +139,13 @@ static void vpr_info_dq(const struct ddebug_query *query, const char *msg)
fmtlen--;
}

- v3pr_info("%s: func=\"%s\" file=\"%s\" module=\"%s\" format=\"%.*s\" lineno=%u-%u\n",
+ v3pr_info("%s: func=\"%s\" file=\"%s\" module=\"%s\" format=\"%.*s\" lineno=%u-%u class=%u\n",
msg,
query->function ?: "",
query->filename ?: "",
query->module ?: "",
fmtlen, query->format ?: "",
- query->first_lineno, query->last_lineno);
+ query->first_lineno, query->last_lineno, query->class_id);
}

/*
@@ -174,6 +175,10 @@ static int ddebug_change(const struct ddebug_query *query,
for (i = 0; i < dt->num_ddebugs; i++) {
struct _ddebug *dp = &dt->ddebugs[i];

+ /* match against the class_id, if > 0 */
+ if (query->class_id && query->class_id != dp->class_id)
+ continue;
+
/* match against the source filename */
if (query->filename &&
!match_wildcard(query->filename, dp->filename) &&
@@ -310,6 +315,22 @@ static inline int parse_lineno(const char *str, unsigned int *val)
}
return 0;
}
+/*
+ * class_id is 0-15. 0 is default, is nonsense in active search
+ */
+static inline int parse_class(struct ddebug_query *query, const char *str)
+{
+ int rc;
+ unsigned int val;
+
+ rc = kstrtouint(str, 10, &val);
+ if (rc < 0 || !val || val > 15) {
+ pr_err("expecting class:[1-15], not %s\n", str);
+ return -EINVAL;
+ }
+ query->class_id = val;
+ return 0;
+}

static int parse_linerange(struct ddebug_query *query, const char *first)
{
@@ -424,6 +445,9 @@ static int ddebug_parse_query(char *words[], int nwords,
} else if (!strcmp(keyword, "line")) {
if (parse_linerange(query, arg))
return -EINVAL;
+ } else if (!strcmp(keyword, "class")) {
+ if (parse_class(query, arg))
+ return -EINVAL;
} else {
pr_err("unknown keyword \"%s\"\n", keyword);
return -EINVAL;
@@ -1007,7 +1031,7 @@ static int ddebug_proc_show(struct seq_file *m, void *p)
iter->table->mod_name, dp->function,
ddebug_describe_flags(dp->flags, &flags));
seq_escape(m, dp->format, "\t\r\n\"");
- seq_puts(m, "\"\n");
+ seq_printf(m, "\" cls:%u\n", dp->class_id);

return 0;
}
--
2.33.1