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Subject[PATCH v5 12/33] dyndbg: add class_id to pr_debug callsites
Date
DRM issues ~10 exclusive categories of debug messages; to represent
this directly in dyndbg, add a new field: struct _ddebug.class_id:5.

This gives us 32 classes, which is a practical usability limit
with a bitmap interface:

#> echo 0x012345678 > /sys/module/drm/parameters/debug

All existing callsites are initialized with _DPRINTK_CLASS_DFLT, which
is 2^5-1. This reserves 0-30 for use in new categorized/class'd
pr_debugs, which fits perfectly with natural enums (ints: 0..N).

Then extend the init macro: DEFINE_DYNAMIC_DEBUG_METADATA() with
_CLS(cls, ...), and redef old name using extended name.

And extend the factory macro callchain with _cls() versions to provide
the callsite.class_id, with old-names passing _DPRINTK_CLASS_DFLT.

This sets us up to create class'd prdebug callsites (class'd callsites
are those with .class_id != _DPRINTK_CLASS_DFLT).

No behavior change.

cc: Rasmus Villemoes <rasmus.villemoes@prevas.dk>
Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
---
include/linux/dynamic_debug.h | 71 +++++++++++++++++++++++++++--------
1 file changed, 55 insertions(+), 16 deletions(-)

diff --git a/include/linux/dynamic_debug.h b/include/linux/dynamic_debug.h
index 6a2001250da1..b6803f7e818f 100644
--- a/include/linux/dynamic_debug.h
+++ b/include/linux/dynamic_debug.h
@@ -6,6 +6,8 @@
#include <linux/jump_label.h>
#endif

+#include <linux/build_bug.h>
+
/*
* An instance of this structure is created in a special
* ELF section at every dynamic debug callsite. At runtime,
@@ -21,6 +23,9 @@ struct _ddebug {
const char *filename;
const char *format;
unsigned int lineno:18;
+#define CLS_BITS 5
+ unsigned int class_id:CLS_BITS;
+#define _DPRINTK_CLASS_DFLT ((1 << CLS_BITS) - 1)
/*
* The flags field controls the behaviour at the callsite.
* The bits here are changed dynamically when the user
@@ -88,7 +93,7 @@ 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, \
@@ -97,8 +102,14 @@ void __dynamic_ibdev_dbg(struct _ddebug *descriptor,
.format = (fmt), \
.lineno = __LINE__, \
.flags = _DPRINTK_FLAGS_DEFAULT, \
+ .class_id = cls, \
_DPRINTK_KEY_INIT \
- }
+ }; \
+ BUILD_BUG_ON_MSG(cls > _DPRINTK_CLASS_DFLT, \
+ "classid value overflow")
+
+#define DEFINE_DYNAMIC_DEBUG_METADATA(name, fmt) \
+ DEFINE_DYNAMIC_DEBUG_METADATA_CLS(name, _DPRINTK_CLASS_DFLT, fmt)

#ifdef CONFIG_JUMP_LABEL

@@ -129,17 +140,34 @@ 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__); \
-} while (0)
-
-#define __dynamic_func_call_no_desc(id, fmt, func, ...) do { \
- DEFINE_DYNAMIC_DEBUG_METADATA(id, fmt); \
+/*
+ * Factory macros: ($prefix)dynamic_func_call($suffix)
+ *
+ * Lower layer (with __ prefix) gets the callsite metadata, and wraps
+ * the func inside a debug-branch/static-key construct. Upper layer
+ * (with _ prefix) does the UNIQUE_ID once, so that lower can ref the
+ * name/label multiple times, and tie the elements together.
+ * Multiple flavors:
+ * (|_cls): adds in _DPRINT_CLASS_DFLT as needed
+ * (|_no_desc): former gets callsite descriptor as 1st arg (for prdbgs)
+ */
+#define __dynamic_func_call_cls(id, cls, fmt, func, ...) do { \
+ DEFINE_DYNAMIC_DEBUG_METADATA_CLS(id, cls, fmt); \
if (DYNAMIC_DEBUG_BRANCH(id)) \
- func(__VA_ARGS__); \
+ func(&id, ##__VA_ARGS__); \
} while (0)
+#define __dynamic_func_call(id, fmt, func, ...) \
+ __dynamic_func_call_cls(id, _DPRINTK_CLASS_DFLT, fmt, \
+ func, ##__VA_ARGS__)
+
+#define __dynamic_func_call_cls_no_desc(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_cls_no_desc(id, _DPRINTK_CLASS_DFLT, \
+ fmt, func, ##__VA_ARGS__)

/*
* "Factory macro" for generating a call to func, guarded by a
@@ -149,22 +177,33 @@ 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(_DPRINTK_CLASS_DFLT, 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_cls_no_desc(cls, fmt, func, ...) \
+ __dynamic_func_call_cls_no_desc(__UNIQUE_ID(ddebug), cls, fmt, \
+ func, ##__VA_ARGS__)
+#define _dynamic_func_call_no_desc(fmt, func, ...) \
+ _dynamic_func_call_cls_no_desc(_DPRINTK_CLASS_DFLT, fmt, \
+ func, ##__VA_ARGS__)
+
+#define dynamic_pr_debug_cls(cls, fmt, ...) \
+ _dynamic_func_call_cls(cls, fmt, __dynamic_pr_debug, \
+ pr_fmt(fmt), ##__VA_ARGS__)

#define dynamic_pr_debug(fmt, ...) \
- _dynamic_func_call(fmt, __dynamic_pr_debug, \
+ _dynamic_func_call(fmt, __dynamic_pr_debug, \
pr_fmt(fmt), ##__VA_ARGS__)

#define dynamic_dev_dbg(dev, fmt, ...) \
- _dynamic_func_call(fmt,__dynamic_dev_dbg, \
+ _dynamic_func_call(fmt, __dynamic_dev_dbg, \
dev, fmt, ##__VA_ARGS__)

#define dynamic_netdev_dbg(dev, fmt, ...) \
--
2.37.1
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