[PATCH v7 00/25] fix DRM_USE_DYNAMIC_DEBUG=y regression

[PATCH v7 00/25] fix DRM_USE_DYNAMIC_DEBUG=y regression

[Jim Cromie]

hi Jason, DRM-folk

This patchest fixes the chicken-egg initialization problem in the 1st
version of ddebug-class-maps, that DRM-CI uncovered.

The root-problem was DECLARE_DYNDBG_CLASSMAP, which broke the K&R rule:
"define once, refer many".  In patch 14 it is replaced by:

 DYNDBG_CLASSMAP_DEFINE - define and export a struct ddebug_class_map
 DYNDBG_CLASSMAP_USE - ref the exported struct

test-dynamic-debug is also extended with a -submod.ko, in order to
recapitulate the drm & drivers initialization scenario.

They're on v6.6-rc5 now, and apply cleanly to drm-tip/drm-tip.

Ive been running recent revs on rc3+, on my desktop and laptop.

The final blocker was a missing __align(8) on the ddebug_class_user
record inserted by DYNDBG_CLASSMAP_USE.  This caused DRM=y (builtin
only) to have a corrupt record for drm_kms_helper (builtin dependent).
Curiously, a clang build did not exhibit this problem.

Heres a part of dmesg, for a DRM=y kernel, booted with
     dynamic_debug.verbose=3 drm.debug=0x10

[    0.466747] dyndbg: add-module: drm 406 sites
[    0.467569] dyndbg: classes[0]: module:drm base:0 len:10 type:DISJOINT_BITS
[    0.467743] dyndbg: module:drm attached 1 classes
[    0.468557] dyndbg: builtin class: module:drm base:0 len:10 type:DISJOINT_BITS
[    0.468742] dyndbg:  found kp:drm.debug =0x10
[    0.468743] dyndbg:   mapped to: module:drm base:0 len:10 type:DISJOINT_BITS
[    0.469742] dyndbg:   drm.debug: classbits: 0x10
[    0.470573] dyndbg: apply bitmap: 0x10 to: 0x0 for drm
[    0.470743] dyndbg: query 0: "class DRM_UT_ATOMIC +p" mod:drm
[    0.471743] dyndbg: split into words: "class" "DRM_UT_ATOMIC" "+p"
[    0.472743] dyndbg: op='+' flags=0x1 maskp=0xffffffff
[    0.473679] dyndbg: parsed: func="" file="" module="drm" format="" lineno=0-0 class=DRM_UT_ATOMIC
[    0.473749] dyndbg: processed 1 queries, with 0 matches, 0 errs
[    0.474742] dyndbg: bit_4: 0 matches on class: DRM_UT_ATOMIC -> 0x10
[    0.475742] dyndbg: applied bitmap: 0x10 to: 0x0 for drm
[    0.476686] dyndbg: 406 debug prints in module drm
[    0.476743] dyndbg: add-module: drm_kms_helper 93 sites
[    0.477727] dyndbg: class_ref[0] drm_kms_helper -> drm module:drm base:0 len:10 type:DISJOINT_BITS
[    0.477743] dyndbg: builtin class: module:drm base:0 len:10 type:DISJOINT_BITS
[    0.478742] dyndbg:  found kp:drm.debug =0x10
[    0.478743] dyndbg:   mapped to: module:drm base:0 len:10 type:DISJOINT_BITS
[    0.479743] dyndbg:   drm.debug: classbits: 0x10
[    0.480592] dyndbg: apply bitmap: 0x10 to: 0x0 for drm_kms_helper
[    0.480743] dyndbg: query 0: "class DRM_UT_ATOMIC +p" mod:drm_kms_helper
[    0.481743] dyndbg: split into words: "class" "DRM_UT_ATOMIC" "+p"
[    0.482743] dyndbg: op='+' flags=0x1 maskp=0xffffffff
[    0.483743] dyndbg: parsed: func="" file="" module="drm_kms_helper" format="" lineno=0-0 class=DRM_UT_ATOMIC
[    0.484750] dyndbg: class-ref: drm_kms_helper.DRM_UT_ATOMIC  module:drm_kms_helper nd:93 nc:0 nu:1
[    0.485809] dyndbg: processed 1 queries, with 44 matches, 0 errs
[    0.486742] dyndbg: bit_4: 44 matches on class: DRM_UT_ATOMIC -> 0x10
[    0.487742] dyndbg: applied bitmap: 0x10 to: 0x0 for drm_kms_helper
[    0.488743] dyndbg: attach-client-module:  module:drm_kms_helper nd:93 nc:0 nu:1
[    0.489742] dyndbg:  93 debug prints in module drm_kms_helper

Widespread testing is appreciated.
I have scripts if anyone wants them.

I'll forward lkp-robot reports here when I get them.

Jim Cromie (25):
  test-dyndbg: fixup CLASSMAP usage error
  dyndbg: reword "class unknown," to "class:_UNKNOWN_"
  dyndbg: make ddebug_class_param union members same size
  dyndbg: replace classmap list with a vector
  dyndbg: ddebug_apply_class_bitmap - add module arg, select on it
  dyndbg: split param_set_dyndbg_classes to module/wrapper fns
  dyndbg: drop NUM_TYPE_ARRAY
  dyndbg: reduce verbose/debug clutter
  dyndbg: silence debugs with no-change updates
  dyndbg: tighten ddebug_class_name() 1st arg type
  dyndbg: tighten fn-sig of ddebug_apply_class_bitmap
  dyndbg: reduce verbose=3 messages in ddebug_add_module
  dyndbg-API: remove DD_CLASS_TYPE_(DISJOINT|LEVEL)_NAMES and code
  dyndbg-API: fix CONFIG_DRM_USE_DYNAMIC_DEBUG regression
  dyndbg: add for_each_boxed_vector
  dyndbg: refactor ddebug_classparam_clamp_input
  dyndbg-API: promote DYNDBG_CLASSMAP_PARAM to API
  dyndbg-doc: add classmap info to howto
  dyndbg: reserve flag bit _DPRINTK_FLAGS_PREFIX_CACHED
  dyndbg: add _DPRINTK_FLAGS_INCL_LOOKUP
  dyndbg: refactor *dynamic_emit_prefix
  dyndbg: improve err report in attach_user_module_classes
  drm: use correct ccflags-y spelling
  drm-drivers: DRM_CLASSMAP_USE in 2nd batch of drivers, helpers
  drm: restore CONFIG_DRM_USE_DYNAMIC_DEBUG un-BROKEN

 .../admin-guide/dynamic-debug-howto.rst       |  59 ++-
 MAINTAINERS                                   |   2 +-
 drivers/gpu/drm/Kconfig                       |   3 +-
 drivers/gpu/drm/Makefile                      |   3 +-
 drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c       |  12 +-
 drivers/gpu/drm/display/drm_dp_helper.c       |  12 +-
 drivers/gpu/drm/drm_crtc_helper.c             |  12 +-
 drivers/gpu/drm/drm_gem_shmem_helper.c        |   2 +
 drivers/gpu/drm/drm_print.c                   |  35 +-
 drivers/gpu/drm/gud/gud_drv.c                 |   2 +
 drivers/gpu/drm/i915/i915_params.c            |  12 +-
 drivers/gpu/drm/mgag200/mgag200_drv.c         |   2 +
 drivers/gpu/drm/nouveau/nouveau_drm.c         |  12 +-
 drivers/gpu/drm/qxl/qxl_drv.c                 |   2 +
 drivers/gpu/drm/radeon/radeon_drv.c           |   2 +
 drivers/gpu/drm/udl/udl_main.c                |   2 +
 drivers/gpu/drm/vkms/vkms_drv.c               |   2 +
 drivers/gpu/drm/vmwgfx/vmwgfx_drv.c           |   2 +
 include/asm-generic/vmlinux.lds.h             |   1 +
 include/drm/drm_print.h                       |  12 +-
 include/linux/dynamic_debug.h                 | 121 +++--
 kernel/module/main.c                          |   3 +
 lib/Kconfig.debug                             |  22 +-
 lib/Makefile                                  |   3 +
 lib/dynamic_debug.c                           | 478 +++++++++++-------
 lib/test_dynamic_debug.c                      | 137 ++---
 lib/test_dynamic_debug_submod.c               |  17 +
 27 files changed, 599 insertions(+), 373 deletions(-)
 create mode 100644 lib/test_dynamic_debug_submod.c

-- 
2.41.0

[PATCH v7 01/25] test-dyndbg: fixup CLASSMAP usage error

[Jim Cromie]

more careful reading of test output reveals:

lib/test_dynamic_debug.c:103 [test_dynamic_debug]do_cats =pmf "doing categories\n"
lib/test_dynamic_debug.c:105 [test_dynamic_debug]do_cats =p "LOW msg\n" class:MID
lib/test_dynamic_debug.c:106 [test_dynamic_debug]do_cats =p "MID msg\n" class:HI
lib/test_dynamic_debug.c:107 [test_dynamic_debug]do_cats =_ "HI msg\n" class unknown, _id:13

That last line is wrong, the HI class is declared.

But the enum's 1st val (explicitly initialized) was wrong; it must be
_base, not _base+1 (a DECLARE_DYNDBG_CLASSMAP[1] param).  So the last
enumeration exceeded the range of mapped class-id's, which triggered
the "class unknown" report.  I intentionally coded in an error, but
forgot to verify its detection and remove it.

RFC:

This patch fixes a bad usage of DECLARE_DYNDBG_CLASSMAP(), showing
that it is too error-prone.  As noted in test-mod comments:

 * Using the CLASSMAP api:
 * - classmaps must have corresponding enum
 * - enum symbols must match/correlate with class-name strings in the map.
 * - base must equal enum's 1st value
 * - multiple maps must set their base to share the 0-62 class_id space !!
 *   (build-bug-on tips welcome)

Those shortcomings could largely be fixed with a __stringify_list
(which doesn't exist,) used in DECLARE_DYNDBG_CLASSMAP to stringify
__VA_ARGS__.  Then, API would accept DRM_UT_* values literally; all
the categories, in order, and not their stringifications, which
created all the usage complications above.

[1] name changes later to DYNDBG_CLASSMAP_DEFINE

Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
---
 lib/test_dynamic_debug.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lib/test_dynamic_debug.c b/lib/test_dynamic_debug.c
index 8dd250ad022b..a01f0193a419 100644
--- a/lib/test_dynamic_debug.c
+++ b/lib/test_dynamic_debug.c
@@ -75,7 +75,7 @@ DD_SYS_WRAP(disjoint_bits, p);
 DD_SYS_WRAP(disjoint_bits, T);
 
 /* symbolic input, independent bits */
-enum cat_disjoint_names { LOW = 11, MID, HI };
+enum cat_disjoint_names { LOW = 10, MID, HI };
 DECLARE_DYNDBG_CLASSMAP(map_disjoint_names, DD_CLASS_TYPE_DISJOINT_NAMES, 10,
 			"LOW", "MID", "HI");
 DD_SYS_WRAP(disjoint_names, p);
-- 
2.41.0

[PATCH v7 02/25] dyndbg: reword "class unknown," to "class:_UNKNOWN_"

[Jim Cromie]

This appears in the control-file to report an unknown class-name, which
indicates that the class_id is not authorized, and dyndbg will ignore
changes to it.  Generally, this means that a DYNDBG_CLASSMAP_DEFINE or
DYNDBG_CLASSMAP_USE is missing.

But the word "unknown" appears in quite a few prdbg formats, so thats
a suboptimal search term to find occurrences of the problem.  Thus
change it to "_UNKNOWN_" which properly shouts the condition.

Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
---
 lib/dynamic_debug.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lib/dynamic_debug.c b/lib/dynamic_debug.c
index 6fba6423cc10..ceb3067a5c83 100644
--- a/lib/dynamic_debug.c
+++ b/lib/dynamic_debug.c
@@ -1151,7 +1151,7 @@ static int ddebug_proc_show(struct seq_file *m, void *p)
 		if (class)
 			seq_printf(m, " class:%s", class);
 		else
-			seq_printf(m, " class unknown, _id:%d", dp->class_id);
+			seq_printf(m, " class:_UNKNOWN_ _id:%d", dp->class_id);
 	}
 	seq_puts(m, "\n");
 
-- 
2.41.0

[PATCH v7 03/25] dyndbg: make ddebug_class_param union members same size

[Jim Cromie]

struct ddebug_class_param keeps a ref to the state-storage of the
param, make both flavors use the same unsigned long under-type.
ISTM this is simpler and safer.

Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
---
 include/linux/dynamic_debug.h | 2 +-
 lib/dynamic_debug.c           | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/include/linux/dynamic_debug.h b/include/linux/dynamic_debug.h
index 4fcbf4d4fd0a..5231aaf361c4 100644
--- a/include/linux/dynamic_debug.h
+++ b/include/linux/dynamic_debug.h
@@ -124,7 +124,7 @@ struct _ddebug_info {
 struct ddebug_class_param {
 	union {
 		unsigned long *bits;
-		unsigned int *lvl;
+		unsigned long *lvl;
 	};
 	char flags[8];
 	const struct ddebug_class_map *map;
diff --git a/lib/dynamic_debug.c b/lib/dynamic_debug.c
index ceb3067a5c83..b984ce338921 100644
--- a/lib/dynamic_debug.c
+++ b/lib/dynamic_debug.c
@@ -796,7 +796,7 @@ int param_get_dyndbg_classes(char *buffer, const struct kernel_param *kp)
 
 	case DD_CLASS_TYPE_LEVEL_NAMES:
 	case DD_CLASS_TYPE_LEVEL_NUM:
-		return scnprintf(buffer, PAGE_SIZE, "%d\n", *dcp->lvl);
+		return scnprintf(buffer, PAGE_SIZE, "%ld\n", *dcp->lvl);
 	default:
 		return -1;
 	}
-- 
2.41.0

[PATCH v7 04/25] dyndbg: replace classmap list with a vector

[Jim Cromie]

Classmaps are stored/linked in a section/array, but are each added to
the module's ddebug_table.maps list-head.

This is unnecessary; even when ddebug_attach_classmap() is handling
the builtin section (with classmaps for multiple builtin modules), its
contents are ordered, so a module's possibly multiple classmaps will
be consecutive in the section, and could be treated as a vector/block,
since both start-addy and subrange length are in the ddebug_info arg.

So this changes:

struct ddebug_class_map drops list-head link.

struct ddebug_table drops the list-head maps, and gets: classes &
num_classes for the start-addy and num_classes, placed to improve
struct packing.

The loading: in ddebug_attach_module_classes(), replace the
for-the-modname list-add loop, with a forloop that finds the module's
subrange (start,length) of matching classmaps within the possibly
builtin classmaps vector, and saves those to the ddebug_table.

The reading/using: change list-foreach loops in ddebug_class_name() &
ddebug_find_valid_class() to walk the array from start to length.

Also:
Move #define __outvar up, above an added use in a fn-prototype.
Simplify ddebug_attach_module_classes args, ref has both addy,len.

no functional changes

Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
---
 include/linux/dynamic_debug.h |  1 -
 lib/dynamic_debug.c           | 61 ++++++++++++++++++-----------------
 2 files changed, 32 insertions(+), 30 deletions(-)

diff --git a/include/linux/dynamic_debug.h b/include/linux/dynamic_debug.h
index 5231aaf361c4..b53217e4b711 100644
--- a/include/linux/dynamic_debug.h
+++ b/include/linux/dynamic_debug.h
@@ -83,7 +83,6 @@ enum class_map_type {
 };
 
 struct ddebug_class_map {
-	struct list_head link;
 	struct module *mod;
 	const char *mod_name;	/* needed for builtins */
 	const char **class_names;
diff --git a/lib/dynamic_debug.c b/lib/dynamic_debug.c
index b984ce338921..a3be2e7c8c84 100644
--- a/lib/dynamic_debug.c
+++ b/lib/dynamic_debug.c
@@ -45,10 +45,11 @@ extern struct ddebug_class_map __start___dyndbg_classes[];
 extern struct ddebug_class_map __stop___dyndbg_classes[];
 
 struct ddebug_table {
-	struct list_head link, maps;
+	struct list_head link;
 	const char *mod_name;
-	unsigned int num_ddebugs;
 	struct _ddebug *ddebugs;
+	struct ddebug_class_map *classes;
+	unsigned int num_ddebugs, num_classes;
 };
 
 struct ddebug_query {
@@ -147,13 +148,15 @@ static void vpr_info_dq(const struct ddebug_query *query, const char *msg)
 		  query->first_lineno, query->last_lineno, query->class_string);
 }
 
+#define __outvar /* filled by callee */
 static struct ddebug_class_map *ddebug_find_valid_class(struct ddebug_table const *dt,
-							  const char *class_string, int *class_id)
+							const char *class_string,
+							__outvar int *class_id)
 {
 	struct ddebug_class_map *map;
-	int idx;
+	int i, idx;
 
-	list_for_each_entry(map, &dt->maps, link) {
+	for (map = dt->classes, i = 0; i < dt->num_classes; i++, map++) {
 		idx = match_string(map->class_names, map->length, class_string);
 		if (idx >= 0) {
 			*class_id = idx + map->base;
@@ -164,7 +167,6 @@ static struct ddebug_class_map *ddebug_find_valid_class(struct ddebug_table cons
 	return NULL;
 }
 
-#define __outvar /* filled by callee */
 /*
  * Search the tables for _ddebug's which match the given `query' and
  * apply the `flags' and `mask' to them.  Returns number of matching
@@ -1111,9 +1113,10 @@ static void *ddebug_proc_next(struct seq_file *m, void *p, loff_t *pos)
 
 static const char *ddebug_class_name(struct ddebug_iter *iter, struct _ddebug *dp)
 {
-	struct ddebug_class_map *map;
+	struct ddebug_class_map *map = iter->table->classes;
+	int i, nc = iter->table->num_classes;
 
-	list_for_each_entry(map, &iter->table->maps, link)
+	for (i = 0; i < nc; i++, map++)
 		if (class_in_range(dp->class_id, map))
 			return map->class_names[dp->class_id - map->base];
 
@@ -1197,30 +1200,31 @@ static const struct proc_ops proc_fops = {
 	.proc_write = ddebug_proc_write
 };
 
-static void ddebug_attach_module_classes(struct ddebug_table *dt,
-					 struct ddebug_class_map *classes,
-					 int num_classes)
+static void ddebug_attach_module_classes(struct ddebug_table *dt, struct _ddebug_info *di)
 {
 	struct ddebug_class_map *cm;
-	int i, j, ct = 0;
+	int i, nc = 0;
 
-	for (cm = classes, i = 0; i < num_classes; i++, cm++) {
+	/*
+	 * Find this module's classmaps in a subrange/wholerange of
+	 * the builtin/modular classmap vector/section.  Save the start
+	 * and length of the subrange at its edges.
+	 */
+	for (cm = di->classes, i = 0; i < di->num_classes; i++, cm++) {
 
 		if (!strcmp(cm->mod_name, dt->mod_name)) {
-
-			v2pr_info("class[%d]: module:%s base:%d len:%d ty:%d\n", i,
-				  cm->mod_name, cm->base, cm->length, cm->map_type);
-
-			for (j = 0; j < cm->length; j++)
-				v3pr_info(" %d: %d %s\n", j + cm->base, j,
-					  cm->class_names[j]);
-
-			list_add(&cm->link, &dt->maps);
-			ct++;
+			if (!nc) {
+				v2pr_info("start subrange, class[%d]: module:%s base:%d len:%d ty:%d\n",
+					  i, cm->mod_name, cm->base, cm->length, cm->map_type);
+				dt->classes = cm;
+			}
+			nc++;
 		}
 	}
-	if (ct)
-		vpr_info("module:%s attached %d classes\n", dt->mod_name, ct);
+	if (nc) {
+		dt->num_classes = nc;
+		vpr_info("module:%s attached %d classes\n", dt->mod_name, nc);
+	}
 }
 
 /*
@@ -1253,10 +1257,9 @@ static int ddebug_add_module(struct _ddebug_info *di, const char *modname)
 	dt->num_ddebugs = di->num_descs;
 
 	INIT_LIST_HEAD(&dt->link);
-	INIT_LIST_HEAD(&dt->maps);
 
 	if (di->classes && di->num_classes)
-		ddebug_attach_module_classes(dt, di->classes, di->num_classes);
+		ddebug_attach_module_classes(dt, di);
 
 	mutex_lock(&ddebug_lock);
 	list_add_tail(&dt->link, &ddebug_tables);
@@ -1369,8 +1372,8 @@ static void ddebug_remove_all_tables(void)
 	mutex_lock(&ddebug_lock);
 	while (!list_empty(&ddebug_tables)) {
 		struct ddebug_table *dt = list_entry(ddebug_tables.next,
-						      struct ddebug_table,
-						      link);
+						     struct ddebug_table,
+						     link);
 		ddebug_table_free(dt);
 	}
 	mutex_unlock(&ddebug_lock);
-- 
2.41.0

[PATCH v7 05/25] dyndbg: ddebug_apply_class_bitmap - add module arg, select on it

[Jim Cromie]

Add query_module param to ddebug_apply_class_bitmap().  This allows
its caller to update just one module, or all (as currently).  We'll
use this later to propagate drm.debug to each USEr as they're
modprobed.

No functional change.

Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
---

after `modprobe i915`, heres the module dependencies,
though not all on drm.debug.

bash-5.2# lsmod
Module                  Size  Used by
i915                 3133440  0
drm_buddy              20480  1 i915
ttm                    90112  1 i915
i2c_algo_bit           16384  1 i915
video                  61440  1 i915
wmi                    32768  1 video
drm_display_helper    200704  1 i915
drm_kms_helper        208896  2 drm_display_helper,i915
drm                   606208  5 drm_kms_helper,drm_display_helper,drm_buddy,i915,ttm
cec                    57344  2 drm_display_helper,i915
---
 lib/dynamic_debug.c | 19 ++++++++++++-------
 1 file changed, 12 insertions(+), 7 deletions(-)

diff --git a/lib/dynamic_debug.c b/lib/dynamic_debug.c
index a3be2e7c8c84..ba41fdeaaf98 100644
--- a/lib/dynamic_debug.c
+++ b/lib/dynamic_debug.c
@@ -601,7 +601,8 @@ static int ddebug_exec_queries(char *query, const char *modname)
 
 /* apply a new bitmap to the sys-knob's current bit-state */
 static int ddebug_apply_class_bitmap(const struct ddebug_class_param *dcp,
-				     unsigned long *new_bits, unsigned long *old_bits)
+				     unsigned long *new_bits, unsigned long *old_bits,
+				     const char *query_modname)
 {
 #define QUERY_SIZE 128
 	char query[QUERY_SIZE];
@@ -609,7 +610,8 @@ static int ddebug_apply_class_bitmap(const struct ddebug_class_param *dcp,
 	int matches = 0;
 	int bi, ct;
 
-	v2pr_info("apply: 0x%lx to: 0x%lx\n", *new_bits, *old_bits);
+	v2pr_info("apply bitmap: 0x%lx to: 0x%lx for %s\n", *new_bits, *old_bits,
+		  query_modname ?: "");
 
 	for (bi = 0; bi < map->length; bi++) {
 		if (test_bit(bi, new_bits) == test_bit(bi, old_bits))
@@ -618,12 +620,15 @@ static int ddebug_apply_class_bitmap(const struct ddebug_class_param *dcp,
 		snprintf(query, QUERY_SIZE, "class %s %c%s", map->class_names[bi],
 			 test_bit(bi, new_bits) ? '+' : '-', dcp->flags);
 
-		ct = ddebug_exec_queries(query, NULL);
+		ct = ddebug_exec_queries(query, query_modname);
 		matches += ct;
 
 		v2pr_info("bit_%d: %d matches on class: %s -> 0x%lx\n", bi,
 			  ct, map->class_names[bi], *new_bits);
 	}
+	v2pr_info("applied bitmap: 0x%lx to: 0x%lx for %s\n", *new_bits, *old_bits,
+		  query_modname ?: "");
+
 	return matches;
 }
 
@@ -679,7 +684,7 @@ static int param_set_dyndbg_classnames(const char *instr, const struct kernel_pa
 				continue;
 			}
 			curr_bits ^= BIT(cls_id);
-			totct += ddebug_apply_class_bitmap(dcp, &curr_bits, dcp->bits);
+			totct += ddebug_apply_class_bitmap(dcp, &curr_bits, dcp->bits, NULL);
 			*dcp->bits = curr_bits;
 			v2pr_info("%s: changed bit %d:%s\n", KP_NAME(kp), cls_id,
 				  map->class_names[cls_id]);
@@ -689,7 +694,7 @@ static int param_set_dyndbg_classnames(const char *instr, const struct kernel_pa
 			old_bits = CLASSMAP_BITMASK(*dcp->lvl);
 			curr_bits = CLASSMAP_BITMASK(cls_id + (wanted ? 1 : 0 ));
 
-			totct += ddebug_apply_class_bitmap(dcp, &curr_bits, &old_bits);
+			totct += ddebug_apply_class_bitmap(dcp, &curr_bits, &old_bits, NULL);
 			*dcp->lvl = (cls_id + (wanted ? 1 : 0));
 			v2pr_info("%s: changed bit-%d: \"%s\" %lx->%lx\n", KP_NAME(kp), cls_id,
 				  map->class_names[cls_id], old_bits, curr_bits);
@@ -752,7 +757,7 @@ int param_set_dyndbg_classes(const char *instr, const struct kernel_param *kp)
 			inrep &= CLASSMAP_BITMASK(map->length);
 		}
 		v2pr_info("bits:%lx > %s\n", inrep, KP_NAME(kp));
-		totct += ddebug_apply_class_bitmap(dcp, &inrep, dcp->bits);
+		totct += ddebug_apply_class_bitmap(dcp, &inrep, dcp->bits, NULL);
 		*dcp->bits = inrep;
 		break;
 	case DD_CLASS_TYPE_LEVEL_NUM:
@@ -765,7 +770,7 @@ int param_set_dyndbg_classes(const char *instr, const struct kernel_param *kp)
 		old_bits = CLASSMAP_BITMASK(*dcp->lvl);
 		new_bits = CLASSMAP_BITMASK(inrep);
 		v2pr_info("lvl:%ld bits:0x%lx > %s\n", inrep, new_bits, KP_NAME(kp));
-		totct += ddebug_apply_class_bitmap(dcp, &new_bits, &old_bits);
+		totct += ddebug_apply_class_bitmap(dcp, &new_bits, &old_bits, NULL);
 		*dcp->lvl = inrep;
 		break;
 	default:
-- 
2.41.0

[PATCH v7 06/25] dyndbg: split param_set_dyndbg_classes to module/wrapper fns

[Jim Cromie]

rename param_set_dyndbg_classes: add _module_ name & arg, old name is
wrapper to new.  New arg allows caller to specify that only one module
is affected by a prdbgs update.

Outer fn preserves kernel_param interface, passing NULL to inner fn.
This selectivity will be used later to narrow the scope of changes
made.

no functional change.

Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
---
 lib/dynamic_debug.c | 37 ++++++++++++++++++++++---------------
 1 file changed, 22 insertions(+), 15 deletions(-)

diff --git a/lib/dynamic_debug.c b/lib/dynamic_debug.c
index ba41fdeaaf98..b67c9b137447 100644
--- a/lib/dynamic_debug.c
+++ b/lib/dynamic_debug.c
@@ -708,18 +708,9 @@ static int param_set_dyndbg_classnames(const char *instr, const struct kernel_pa
 	return 0;
 }
 
-/**
- * param_set_dyndbg_classes - class FOO >control
- * @instr: string echo>d to sysfs, input depends on map_type
- * @kp:    kp->arg has state: bits/lvl, map, map_type
- *
- * Enable/disable prdbgs by their class, as given in the arguments to
- * DECLARE_DYNDBG_CLASSMAP.  For LEVEL map-types, enforce relative
- * levels by bitpos.
- *
- * Returns: 0 or <0 if error.
- */
-int param_set_dyndbg_classes(const char *instr, const struct kernel_param *kp)
+static int param_set_dyndbg_module_classes(const char *instr,
+					   const struct kernel_param *kp,
+					   const char *modnm)
 {
 	const struct ddebug_class_param *dcp = kp->arg;
 	const struct ddebug_class_map *map = dcp->map;
@@ -756,8 +747,8 @@ int param_set_dyndbg_classes(const char *instr, const struct kernel_param *kp)
 				KP_NAME(kp), inrep, CLASSMAP_BITMASK(map->length));
 			inrep &= CLASSMAP_BITMASK(map->length);
 		}
-		v2pr_info("bits:%lx > %s\n", inrep, KP_NAME(kp));
-		totct += ddebug_apply_class_bitmap(dcp, &inrep, dcp->bits, NULL);
+		v2pr_info("bits:0x%lx > %s.%s\n", inrep, modnm ?: "*", KP_NAME(kp));
+		totct += ddebug_apply_class_bitmap(dcp, &inrep, dcp->bits, modnm);
 		*dcp->bits = inrep;
 		break;
 	case DD_CLASS_TYPE_LEVEL_NUM:
@@ -770,7 +761,7 @@ int param_set_dyndbg_classes(const char *instr, const struct kernel_param *kp)
 		old_bits = CLASSMAP_BITMASK(*dcp->lvl);
 		new_bits = CLASSMAP_BITMASK(inrep);
 		v2pr_info("lvl:%ld bits:0x%lx > %s\n", inrep, new_bits, KP_NAME(kp));
-		totct += ddebug_apply_class_bitmap(dcp, &new_bits, &old_bits, NULL);
+		totct += ddebug_apply_class_bitmap(dcp, &new_bits, &old_bits, modnm);
 		*dcp->lvl = inrep;
 		break;
 	default:
@@ -779,6 +770,22 @@ int param_set_dyndbg_classes(const char *instr, const struct kernel_param *kp)
 	vpr_info("%s: total matches: %d\n", KP_NAME(kp), totct);
 	return 0;
 }
+
+/**
+ * param_set_dyndbg_classes - class FOO >control
+ * @instr: string echo>d to sysfs, input depends on map_type
+ * @kp:    kp->arg has state: bits/lvl, map, map_type
+ *
+ * Enable/disable prdbgs by their class, as given in the arguments to
+ * DECLARE_DYNDBG_CLASSMAP.  For LEVEL map-types, enforce relative
+ * levels by bitpos.
+ *
+ * Returns: 0 or <0 if error.
+ */
+int param_set_dyndbg_classes(const char *instr, const struct kernel_param *kp)
+{
+	return param_set_dyndbg_module_classes(instr, kp, NULL);
+}
 EXPORT_SYMBOL(param_set_dyndbg_classes);
 
 /**
-- 
2.41.0

[PATCH v7 07/25] dyndbg: drop NUM_TYPE_ARRAY

[Jim Cromie]

ARRAY_SIZE works here, since array decl is complete.

no functional change

Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
---
 include/linux/dynamic_debug.h | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/include/linux/dynamic_debug.h b/include/linux/dynamic_debug.h
index b53217e4b711..8116d0a0d33a 100644
--- a/include/linux/dynamic_debug.h
+++ b/include/linux/dynamic_debug.h
@@ -106,11 +106,9 @@ struct ddebug_class_map {
 		.mod_name = KBUILD_MODNAME,				\
 		.base = _base,						\
 		.map_type = _maptype,					\
-		.length = NUM_TYPE_ARGS(char*, __VA_ARGS__),		\
+		.length = ARRAY_SIZE(_var##_classnames),		\
 		.class_names = _var##_classnames,			\
 	}
-#define NUM_TYPE_ARGS(eltype, ...)				\
-        (sizeof((eltype[]){__VA_ARGS__}) / sizeof(eltype))
 
 /* encapsulate linker provided built-in (or module) dyndbg data */
 struct _ddebug_info {
-- 
2.41.0

[PATCH v7 08/25] dyndbg: reduce verbose/debug clutter

[Jim Cromie]

currently, for verbose=3, these are logged (blank lines for clarity):

 dyndbg: query 0: "class DRM_UT_CORE +p" mod:*
 dyndbg: split into words: "class" "DRM_UT_CORE" "+p"

 dyndbg: op='+'
 dyndbg: flags=0x1
 dyndbg: *flagsp=0x1 *maskp=0xffffffff

 dyndbg: parsed: func="" file="" module="" format="" lineno=0-0 class=...
 dyndbg: no matches for query
 dyndbg: no-match: func="" file="" module="" format="" lineno=0-0 class=...
 dyndbg: processed 1 queries, with 0 matches, 0 errs

That is excessive, so this patch:
 - shrinks 3 lines of 2nd stanza to single line
 - drops 1st 2 lines of 3rd stanza
   3rd is like 1st, with result, not procedure.
   2nd is just status, retold in 4th, with more info.

Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
---
 lib/dynamic_debug.c | 14 +++-----------
 1 file changed, 3 insertions(+), 11 deletions(-)

diff --git a/lib/dynamic_debug.c b/lib/dynamic_debug.c
index b67c9b137447..b0e11f6bfaa2 100644
--- a/lib/dynamic_debug.c
+++ b/lib/dynamic_debug.c
@@ -266,9 +266,6 @@ static int ddebug_change(const struct ddebug_query *query,
 	}
 	mutex_unlock(&ddebug_lock);
 
-	if (!nfound && verbose)
-		pr_info("no matches for query\n");
-
 	return nfound;
 }
 
@@ -497,7 +494,6 @@ static int ddebug_parse_flags(const char *str, struct flag_settings *modifiers)
 		pr_err("bad flag-op %c, at start of %s\n", *str, str);
 		return -EINVAL;
 	}
-	v3pr_info("op='%c'\n", op);
 
 	for (; *str ; ++str) {
 		for (i = ARRAY_SIZE(opt_array) - 1; i >= 0; i--) {
@@ -511,7 +507,6 @@ static int ddebug_parse_flags(const char *str, struct flag_settings *modifiers)
 			return -EINVAL;
 		}
 	}
-	v3pr_info("flags=0x%x\n", modifiers->flags);
 
 	/* calculate final flags, mask based upon op */
 	switch (op) {
@@ -527,7 +522,7 @@ static int ddebug_parse_flags(const char *str, struct flag_settings *modifiers)
 		modifiers->flags = 0;
 		break;
 	}
-	v3pr_info("*flagsp=0x%x *maskp=0x%x\n", modifiers->flags, modifiers->mask);
+	v3pr_info("op='%c' flags=0x%x maskp=0x%x\n", op, modifiers->flags, modifiers->mask);
 
 	return 0;
 }
@@ -537,7 +532,7 @@ static int ddebug_exec_query(char *query_string, const char *modname)
 	struct flag_settings modifiers = {};
 	struct ddebug_query query = {};
 #define MAXWORDS 9
-	int nwords, nfound;
+	int nwords;
 	char *words[MAXWORDS];
 
 	nwords = ddebug_tokenize(query_string, words, MAXWORDS);
@@ -555,10 +550,7 @@ static int ddebug_exec_query(char *query_string, const char *modname)
 		return -EINVAL;
 	}
 	/* actually go and implement the change */
-	nfound = ddebug_change(&query, &modifiers);
-	vpr_info_dq(&query, nfound ? "applied" : "no-match");
-
-	return nfound;
+	return ddebug_change(&query, &modifiers);
 }
 
 /* handle multiple queries in query string, continue on error, return
-- 
2.41.0

[PATCH v7 09/25] dyndbg: silence debugs with no-change updates

[Jim Cromie]

check for actual changes before announcing them, declutter logs.

Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
---
 lib/dynamic_debug.c | 12 +++++++-----
 1 file changed, 7 insertions(+), 5 deletions(-)

diff --git a/lib/dynamic_debug.c b/lib/dynamic_debug.c
index b0e11f6bfaa2..b07aab422604 100644
--- a/lib/dynamic_debug.c
+++ b/lib/dynamic_debug.c
@@ -591,7 +591,7 @@ static int ddebug_exec_queries(char *query, const char *modname)
 	return nfound;
 }
 
-/* apply a new bitmap to the sys-knob's current bit-state */
+/* apply a new class-param setting */
 static int ddebug_apply_class_bitmap(const struct ddebug_class_param *dcp,
 				     unsigned long *new_bits, unsigned long *old_bits,
 				     const char *query_modname)
@@ -602,8 +602,9 @@ static int ddebug_apply_class_bitmap(const struct ddebug_class_param *dcp,
 	int matches = 0;
 	int bi, ct;
 
-	v2pr_info("apply bitmap: 0x%lx to: 0x%lx for %s\n", *new_bits, *old_bits,
-		  query_modname ?: "");
+	if (*new_bits != *old_bits)
+		v2pr_info("apply bitmap: 0x%lx to: 0x%lx for %s\n", *new_bits,
+			  *old_bits, query_modname ?: "'*'");
 
 	for (bi = 0; bi < map->length; bi++) {
 		if (test_bit(bi, new_bits) == test_bit(bi, old_bits))
@@ -618,8 +619,9 @@ static int ddebug_apply_class_bitmap(const struct ddebug_class_param *dcp,
 		v2pr_info("bit_%d: %d matches on class: %s -> 0x%lx\n", bi,
 			  ct, map->class_names[bi], *new_bits);
 	}
-	v2pr_info("applied bitmap: 0x%lx to: 0x%lx for %s\n", *new_bits, *old_bits,
-		  query_modname ?: "");
+	if (*new_bits != *old_bits)
+		v2pr_info("applied bitmap: 0x%lx to: 0x%lx for %s\n", *new_bits,
+			  *old_bits, query_modname ?: "'*'");
 
 	return matches;
 }
-- 
2.41.0

[PATCH v7 10/25] dyndbg: tighten ddebug_class_name() 1st arg type

[Jim Cromie]

Change function's 1st arg-type, and deref in the caller.
The fn doesn't need any other fields in the struct.

no functional change.

Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
---
 lib/dynamic_debug.c | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/lib/dynamic_debug.c b/lib/dynamic_debug.c
index b07aab422604..8158943b350d 100644
--- a/lib/dynamic_debug.c
+++ b/lib/dynamic_debug.c
@@ -1117,12 +1117,12 @@ static void *ddebug_proc_next(struct seq_file *m, void *p, loff_t *pos)
 #define class_in_range(class_id, map)					\
 	(class_id >= map->base && class_id < map->base + map->length)
 
-static const char *ddebug_class_name(struct ddebug_iter *iter, struct _ddebug *dp)
+static const char *ddebug_class_name(struct ddebug_table *dt, struct _ddebug *dp)
 {
-	struct ddebug_class_map *map = iter->table->classes;
-	int i, nc = iter->table->num_classes;
+	struct ddebug_class_map *map = dt->classes;
+	int i;
 
-	for (i = 0; i < nc; i++, map++)
+	for (i = 0; i < dt->num_classes; i++, map++)
 		if (class_in_range(dp->class_id, map))
 			return map->class_names[dp->class_id - map->base];
 
@@ -1156,7 +1156,7 @@ static int ddebug_proc_show(struct seq_file *m, void *p)
 	seq_puts(m, "\"");
 
 	if (dp->class_id != _DPRINTK_CLASS_DFLT) {
-		class = ddebug_class_name(iter, dp);
+		class = ddebug_class_name(iter->table, dp);
 		if (class)
 			seq_printf(m, " class:%s", class);
 		else
-- 
2.41.0

[PATCH v7 11/25] dyndbg: tighten fn-sig of ddebug_apply_class_bitmap

[Jim Cromie]

old_bits arg is currently a pointer to the input bits, but this could
allow inadvertent changes to the input by the fn.  Disallow this.
And constify new_bits while here.

Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
---
 lib/dynamic_debug.c | 21 +++++++++++----------
 1 file changed, 11 insertions(+), 10 deletions(-)

diff --git a/lib/dynamic_debug.c b/lib/dynamic_debug.c
index 8158943b350d..8beb98a831f5 100644
--- a/lib/dynamic_debug.c
+++ b/lib/dynamic_debug.c
@@ -593,7 +593,8 @@ static int ddebug_exec_queries(char *query, const char *modname)
 
 /* apply a new class-param setting */
 static int ddebug_apply_class_bitmap(const struct ddebug_class_param *dcp,
-				     unsigned long *new_bits, unsigned long *old_bits,
+				     const unsigned long *new_bits,
+				     const unsigned long old_bits,
 				     const char *query_modname)
 {
 #define QUERY_SIZE 128
@@ -602,12 +603,12 @@ static int ddebug_apply_class_bitmap(const struct ddebug_class_param *dcp,
 	int matches = 0;
 	int bi, ct;
 
-	if (*new_bits != *old_bits)
+	if (*new_bits != old_bits)
 		v2pr_info("apply bitmap: 0x%lx to: 0x%lx for %s\n", *new_bits,
-			  *old_bits, query_modname ?: "'*'");
+			  old_bits, query_modname ?: "'*'");
 
 	for (bi = 0; bi < map->length; bi++) {
-		if (test_bit(bi, new_bits) == test_bit(bi, old_bits))
+		if (test_bit(bi, new_bits) == test_bit(bi, &old_bits))
 			continue;
 
 		snprintf(query, QUERY_SIZE, "class %s %c%s", map->class_names[bi],
@@ -619,9 +620,9 @@ static int ddebug_apply_class_bitmap(const struct ddebug_class_param *dcp,
 		v2pr_info("bit_%d: %d matches on class: %s -> 0x%lx\n", bi,
 			  ct, map->class_names[bi], *new_bits);
 	}
-	if (*new_bits != *old_bits)
+	if (*new_bits != old_bits)
 		v2pr_info("applied bitmap: 0x%lx to: 0x%lx for %s\n", *new_bits,
-			  *old_bits, query_modname ?: "'*'");
+			  old_bits, query_modname ?: "'*'");
 
 	return matches;
 }
@@ -678,7 +679,7 @@ static int param_set_dyndbg_classnames(const char *instr, const struct kernel_pa
 				continue;
 			}
 			curr_bits ^= BIT(cls_id);
-			totct += ddebug_apply_class_bitmap(dcp, &curr_bits, dcp->bits, NULL);
+			totct += ddebug_apply_class_bitmap(dcp, &curr_bits, *dcp->bits, NULL);
 			*dcp->bits = curr_bits;
 			v2pr_info("%s: changed bit %d:%s\n", KP_NAME(kp), cls_id,
 				  map->class_names[cls_id]);
@@ -688,7 +689,7 @@ static int param_set_dyndbg_classnames(const char *instr, const struct kernel_pa
 			old_bits = CLASSMAP_BITMASK(*dcp->lvl);
 			curr_bits = CLASSMAP_BITMASK(cls_id + (wanted ? 1 : 0 ));
 
-			totct += ddebug_apply_class_bitmap(dcp, &curr_bits, &old_bits, NULL);
+			totct += ddebug_apply_class_bitmap(dcp, &curr_bits, old_bits, NULL);
 			*dcp->lvl = (cls_id + (wanted ? 1 : 0));
 			v2pr_info("%s: changed bit-%d: \"%s\" %lx->%lx\n", KP_NAME(kp), cls_id,
 				  map->class_names[cls_id], old_bits, curr_bits);
@@ -742,7 +743,7 @@ static int param_set_dyndbg_module_classes(const char *instr,
 			inrep &= CLASSMAP_BITMASK(map->length);
 		}
 		v2pr_info("bits:0x%lx > %s.%s\n", inrep, modnm ?: "*", KP_NAME(kp));
-		totct += ddebug_apply_class_bitmap(dcp, &inrep, dcp->bits, modnm);
+		totct += ddebug_apply_class_bitmap(dcp, &inrep, *dcp->bits, modnm);
 		*dcp->bits = inrep;
 		break;
 	case DD_CLASS_TYPE_LEVEL_NUM:
@@ -755,7 +756,7 @@ static int param_set_dyndbg_module_classes(const char *instr,
 		old_bits = CLASSMAP_BITMASK(*dcp->lvl);
 		new_bits = CLASSMAP_BITMASK(inrep);
 		v2pr_info("lvl:%ld bits:0x%lx > %s\n", inrep, new_bits, KP_NAME(kp));
-		totct += ddebug_apply_class_bitmap(dcp, &new_bits, &old_bits, modnm);
+		totct += ddebug_apply_class_bitmap(dcp, &new_bits, old_bits, modnm);
 		*dcp->lvl = inrep;
 		break;
 	default:
-- 
2.41.0

[PATCH v7 12/25] dyndbg: reduce verbose=3 messages in ddebug_add_module

[Jim Cromie]

The fn currently says "add-module", then "skipping" if the module has
no prdbgs.  Just check 1st and return quietly.

no functional change

Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
---
 lib/dynamic_debug.c | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/lib/dynamic_debug.c b/lib/dynamic_debug.c
index 8beb98a831f5..45870a699507 100644
--- a/lib/dynamic_debug.c
+++ b/lib/dynamic_debug.c
@@ -1242,11 +1242,10 @@ static int ddebug_add_module(struct _ddebug_info *di, const char *modname)
 {
 	struct ddebug_table *dt;
 
-	v3pr_info("add-module: %s.%d sites\n", modname, di->num_descs);
-	if (!di->num_descs) {
-		v3pr_info(" skip %s\n", modname);
+	if (!di->num_descs)
 		return 0;
-	}
+
+	v3pr_info("add-module: %s %d sites\n", modname, di->num_descs);
 
 	dt = kzalloc(sizeof(*dt), GFP_KERNEL);
 	if (dt == NULL) {
-- 
2.41.0

[PATCH v7 13/25] dyndbg-API: remove DD_CLASS_TYPE_(DISJOINT|LEVEL)_NAMES and code

[Jim Cromie]

Remove the NAMED class types; these 2 classmap types accept class
names at the PARAM interface, for example:

  echo +DRM_UT_CORE,-DRM_UT_KMS > /sys/module/drm/parameters/debug_names

The code works, but its only used by test-dynamic-debug, and wasn't
asked for by anyone else, so simplify things for now.

Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
---
 include/linux/dynamic_debug.h |  19 ++-----
 lib/dynamic_debug.c           | 103 +++-------------------------------
 lib/test_dynamic_debug.c      |  12 ----
 3 files changed, 12 insertions(+), 122 deletions(-)

diff --git a/include/linux/dynamic_debug.h b/include/linux/dynamic_debug.h
index 8116d0a0d33a..8eaf8eabdc8d 100644
--- a/include/linux/dynamic_debug.h
+++ b/include/linux/dynamic_debug.h
@@ -61,24 +61,13 @@ struct _ddebug {
 enum class_map_type {
 	DD_CLASS_TYPE_DISJOINT_BITS,
 	/**
-	 * DD_CLASS_TYPE_DISJOINT_BITS: classes are independent, one per bit.
-	 * expecting hex input. Built for drm.debug, basis for other types.
+	 * DD_CLASS_TYPE_DISJOINT_BITS: classes are independent, mapped to bits[0..N].
+	 * Expects hex input. Built for drm.debug, basis for other types.
 	 */
 	DD_CLASS_TYPE_LEVEL_NUM,
 	/**
-	 * DD_CLASS_TYPE_LEVEL_NUM: input is numeric level, 0-N.
-	 * N turns on just bits N-1 .. 0, so N=0 turns all bits off.
-	 */
-	DD_CLASS_TYPE_DISJOINT_NAMES,
-	/**
-	 * DD_CLASS_TYPE_DISJOINT_NAMES: input is a CSV of [+-]CLASS_NAMES,
-	 * classes are independent, like _DISJOINT_BITS.
-	 */
-	DD_CLASS_TYPE_LEVEL_NAMES,
-	/**
-	 * DD_CLASS_TYPE_LEVEL_NAMES: input is a CSV of [+-]CLASS_NAMES,
-	 * intended for names like: INFO,DEBUG,TRACE, with a module prefix
-	 * avoid EMERG,ALERT,CRIT,ERR,WARNING: they're not debug
+	 * DD_CLASS_TYPE_LEVEL_NUM: input is numeric level, 0..N.
+	 * Input N turns on bits 0..N-1
 	 */
 };
 
diff --git a/lib/dynamic_debug.c b/lib/dynamic_debug.c
index 45870a699507..91c8b67fd8f8 100644
--- a/lib/dynamic_debug.c
+++ b/lib/dynamic_debug.c
@@ -632,77 +632,6 @@ static int ddebug_apply_class_bitmap(const struct ddebug_class_param *dcp,
 
 #define CLASSMAP_BITMASK(width) ((1UL << (width)) - 1)
 
-/* accept comma-separated-list of [+-] classnames */
-static int param_set_dyndbg_classnames(const char *instr, const struct kernel_param *kp)
-{
-	const struct ddebug_class_param *dcp = kp->arg;
-	const struct ddebug_class_map *map = dcp->map;
-	unsigned long curr_bits, old_bits;
-	char *cl_str, *p, *tmp;
-	int cls_id, totct = 0;
-	bool wanted;
-
-	cl_str = tmp = kstrdup(instr, GFP_KERNEL);
-	p = strchr(cl_str, '\n');
-	if (p)
-		*p = '\0';
-
-	/* start with previously set state-bits, then modify */
-	curr_bits = old_bits = *dcp->bits;
-	vpr_info("\"%s\" > %s:0x%lx\n", cl_str, KP_NAME(kp), curr_bits);
-
-	for (; cl_str; cl_str = p) {
-		p = strchr(cl_str, ',');
-		if (p)
-			*p++ = '\0';
-
-		if (*cl_str == '-') {
-			wanted = false;
-			cl_str++;
-		} else {
-			wanted = true;
-			if (*cl_str == '+')
-				cl_str++;
-		}
-		cls_id = match_string(map->class_names, map->length, cl_str);
-		if (cls_id < 0) {
-			pr_err("%s unknown to %s\n", cl_str, KP_NAME(kp));
-			continue;
-		}
-
-		/* have one or more valid class_ids of one *_NAMES type */
-		switch (map->map_type) {
-		case DD_CLASS_TYPE_DISJOINT_NAMES:
-			/* the +/- pertains to a single bit */
-			if (test_bit(cls_id, &curr_bits) == wanted) {
-				v3pr_info("no change on %s\n", cl_str);
-				continue;
-			}
-			curr_bits ^= BIT(cls_id);
-			totct += ddebug_apply_class_bitmap(dcp, &curr_bits, *dcp->bits, NULL);
-			*dcp->bits = curr_bits;
-			v2pr_info("%s: changed bit %d:%s\n", KP_NAME(kp), cls_id,
-				  map->class_names[cls_id]);
-			break;
-		case DD_CLASS_TYPE_LEVEL_NAMES:
-			/* cls_id = N in 0..max. wanted +/- determines N or N-1 */
-			old_bits = CLASSMAP_BITMASK(*dcp->lvl);
-			curr_bits = CLASSMAP_BITMASK(cls_id + (wanted ? 1 : 0 ));
-
-			totct += ddebug_apply_class_bitmap(dcp, &curr_bits, old_bits, NULL);
-			*dcp->lvl = (cls_id + (wanted ? 1 : 0));
-			v2pr_info("%s: changed bit-%d: \"%s\" %lx->%lx\n", KP_NAME(kp), cls_id,
-				  map->class_names[cls_id], old_bits, curr_bits);
-			break;
-		default:
-			pr_err("illegal map-type value %d\n", map->map_type);
-		}
-	}
-	kfree(tmp);
-	vpr_info("total matches: %d\n", totct);
-	return 0;
-}
-
 static int param_set_dyndbg_module_classes(const char *instr,
 					   const struct kernel_param *kp,
 					   const char *modnm)
@@ -711,29 +640,17 @@ static int param_set_dyndbg_module_classes(const char *instr,
 	const struct ddebug_class_map *map = dcp->map;
 	unsigned long inrep, new_bits, old_bits;
 	int rc, totct = 0;
-
-	switch (map->map_type) {
-
-	case DD_CLASS_TYPE_DISJOINT_NAMES:
-	case DD_CLASS_TYPE_LEVEL_NAMES:
-		/* handle [+-]classnames list separately, we are done here */
-		return param_set_dyndbg_classnames(instr, kp);
-
-	case DD_CLASS_TYPE_DISJOINT_BITS:
-	case DD_CLASS_TYPE_LEVEL_NUM:
-		/* numeric input, accept and fall-thru */
-		rc = kstrtoul(instr, 0, &inrep);
-		if (rc) {
-			pr_err("expecting numeric input: %s > %s\n", instr, KP_NAME(kp));
-			return -EINVAL;
-		}
-		break;
-	default:
-		pr_err("%s: bad map type: %d\n", KP_NAME(kp), map->map_type);
+	char *nl;
+
+	rc = kstrtoul(instr, 0, &inrep);
+	if (rc) {
+		nl = strchr(instr, '\n');
+		if (nl)
+			*nl = '\0';
+		pr_err("expecting numeric input, not: %s > %s\n", instr, KP_NAME(kp));
 		return -EINVAL;
 	}
 
-	/* only _BITS,_NUM (numeric) map-types get here */
 	switch (map->map_type) {
 	case DD_CLASS_TYPE_DISJOINT_BITS:
 		/* expect bits. mask and warn if too many */
@@ -798,12 +715,8 @@ int param_get_dyndbg_classes(char *buffer, const struct kernel_param *kp)
 	const struct ddebug_class_map *map = dcp->map;
 
 	switch (map->map_type) {
-
-	case DD_CLASS_TYPE_DISJOINT_NAMES:
 	case DD_CLASS_TYPE_DISJOINT_BITS:
 		return scnprintf(buffer, PAGE_SIZE, "0x%lx\n", *dcp->bits);
-
-	case DD_CLASS_TYPE_LEVEL_NAMES:
 	case DD_CLASS_TYPE_LEVEL_NUM:
 		return scnprintf(buffer, PAGE_SIZE, "%ld\n", *dcp->lvl);
 	default:
diff --git a/lib/test_dynamic_debug.c b/lib/test_dynamic_debug.c
index a01f0193a419..229eaadee838 100644
--- a/lib/test_dynamic_debug.c
+++ b/lib/test_dynamic_debug.c
@@ -102,10 +102,6 @@ static void do_cats(void)
 {
 	pr_debug("doing categories\n");
 
-	prdbg(LOW);
-	prdbg(MID);
-	prdbg(HI);
-
 	prdbg(D2_CORE);
 	prdbg(D2_DRIVER);
 	prdbg(D2_KMS);
@@ -129,14 +125,6 @@ static void do_levels(void)
 	prdbg(V5);
 	prdbg(V6);
 	prdbg(V7);
-
-	prdbg(L1);
-	prdbg(L2);
-	prdbg(L3);
-	prdbg(L4);
-	prdbg(L5);
-	prdbg(L6);
-	prdbg(L7);
 }
 
 static void do_prints(void)
-- 
2.41.0

[PATCH v7 14/25] dyndbg-API: fix CONFIG_DRM_USE_DYNAMIC_DEBUG regression

[Jim Cromie]

DECLARE_DYNDBG_CLASSMAP() has a design error; it fails a basic K&R
rule: "define once, refer many times".

When DRM_USE_DYNAMIC_DEBUG=y, DECLARE_DYNDBG_CLASSMAP() is used across
DRM core & drivers; they all repeat the same classmap-defn args, which
must match for the modules to respond together when DRM.debug
categories are enabled.

Worse, it causes the CONFIG_DRM_USE_DYNAMIC_DEBUG=Y regression; 1st
drm.ko loads, and dyndbg initializes its DRM.debug callsites, then a
drm-driver loads, but too late - it missed the DRM.debug enablement.

So replace it with 2 macros:
  DYNDBG_CLASSMAP_DEFINE - invoked once from core - drm.ko
  DYNDBG_CLASSMAP_USE    - from all drm drivers and helpers.

DYNDBG_CLASSMAP_DEFINE: based on DECLARE_DYNDBG_CLASSMAP, but now it
drops the static on the constructed classmap variable, and exports it
instead.

DYNDBG_CLASSMAP_USE: then refers to the exported var by name:
* used from drivers, helper-mods
* lets us drop the repetitive "classname" args
* fixes 2nd-defn problem
* creates a ddebug_class_user record in new __dyndbg_class_users section
  this allows ddebug_add_module(etal) to handle them per-module.

The distinction, and the usage record, allows dyndbg to initialize the
driver's DRM.debug callsites separately after it is modprobed.

Since DRM now needs updates to use the new macros, it also gets 2
wrappers: DRM_CLASSMAP_DEFINE, DRM_CLASSMAP_USE which declutter the
users by hiding the ifdef CONFIG_DRM_USE_DYNAMIC_DEBUG.

To review, dyndbg's existing __dyndbg_classes[] section does:

. catalogs the classmaps defined by the module (or builtin modules)
. authorizes dyndbg to >control those class'd prdbgs for the module.
. DYNDBG_CLASSMAP_DEFINE(and old one) creates classmaps in this section.

This patch adds __dyndbg_class_users[] section:

. catalogs uses/references to the classmap definitions.
. authorizes dyndbg to >control those class'd prdbgs in ref'g module.
. DYNDBG_CLASSMAP_USE() creates classmap-user records in this section.

Now ddebug_add_module(etal) can handle classmap-uses like (and after)
classmaps; when a dependent module is loaded, its parent's kernel
params are scanned to find the param wired to dyndbg-param-ops, whose
classmap matches the one ref'd by the client.

To support this, theres a few data/header changes:

. new struct ddebug_class_user
  contains: user-module-name, &classmap-defn
  it records drm-driver's use of a classmap in the section, allowing lookup

struct ddebug_info gets 2 new fields to encapsulate the new section:
  class_users, num_class_users.
  set by dynamic_debug_init() for builtins.
  or by kernel/module/main:load_info() for loadable modules.

vmlinux.lds.h: new BOUNDED_SECTION for __dyndbg_class_users

dynamic_debug.c has 2 changes in ddebug_add_module(), ddebug_change():

ddebug_add_module() already calls ddebug_attach_module_classes()
to handle classmaps DEFINEd by a module, now it also calls
ddebug_attach_user_module_classes() to handle USEd classmaps.  To
avoid this work when possible, 1st scan the module's descriptors and
count the number of class'd pr_debugs.

ddebug_attach_user_module_classes() scans the module's class_users
section, follows the refs to the parent's classmap, and calls
ddebug_apply_params() on each.  It also avoids work by checking the
module's class-ct.

ddebug_apply_params(new fn):

It scans module's/builtin kernel-params, calls ddebug_match_apply_kparam
for each to find the params/sysfs-nodes which may be wired to a classmap.

ddebug_match_apply_kparam(new fn):

1st, it tests the kernel-param.ops is dyndbg's; this guarantees that
the attached arg is a struct ddebug_class_param, which has a ref to
the param's state, and to the classmap defining the param's handling.

2nd, it requires that the classmap ref'd by the kparam is the one
we're called for; modules can use many separate classmaps (as
test_dynamic_debug does).

Then apply the "parent" kparam's setting to the dependent module,
using ddebug_apply_class_bitmap().

ddebug_change(and callees) also gets adjustments:

ddebug_find_valid_class(): This does a search over the module's
classmaps, looking for the class FOO echo'd to >control.  So now it
searches over __dyndbg_class_users[] after __dyndbg_classes[].

ddebug_class_name(): return class-names for defined AND used classes.

test_dynamic_debug.c, test_dynamic_debug_submod.c:

This (already) demonstrates the 2 types of classmaps & sysfs-params,
following the 4-part recipe:

1. define an enum for the classmap: DRM.debug has DRM_UT_{CORE,KMS,...}
   multiple classes must share 0-62 classid space.
2. DYNDBG_CLASSMAP_DEFINE(.. DRM_UT_{CORE,KMS,...})
3. DYNDBG_CLASSMAP_PARAM* (classmap)
4. DYNDBG_CLASSMAP_USE()
   by _submod only, skipping 2,3

Move all the enum declarations together, to better explain how they
share the 0..62 class-id space available to a module (non-overlapping
subranges).

reorg macros 2,3 by name.  This gives a tabular format, making it easy
to see the pattern of repetition, and the points of change.

And extend the test to replicate the 2-module (parent & dependent)
scenario which caused the CONFIG_DRM_USE_DYNAMIC_DEBUG=y regression
seen in drm & drivers.

The _submod.c is a 2-line file: #define _SUBMOD, #include parent.

This gives identical complements of prdbgs in parent & _submod, and
thus identical print behavior when all of: >control, >params, and
parent->_submod propagation are working correctly.

It also puts all the parent/_submod declarations together in the same
source, with the new ifdef _SUBMOD block invoking DYNDBG_CLASSMAP_USE
for the 2 test-interfaces.  I think this is clearer.

These 2 modules are independently configurable, allowing builtin
parent and loadable submod, which recapitulates a troublesome build
combo for drm & drivers.

DEBUG details:

``#define DEBUG`` in src enables all pr_debugs after it, including any
class'd pr_debugs; its not necessarily all-or-nothing, unless its a
one-file-module with DEBUG at the top.

If a CLASSMAP_PARAM is defined on a classmap, its readback value
cannot describe the set of enablements.  The param is basically
write-only; it cannot know if `echo $cmd >control` was done since.

To know the exact pr-debug state with certainty, toggle to both:

   echo 0x3ff > /sys/module/drm/parameters/debug
   echo 0     > /sys/module/drm/parameters/debug

Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Jani Nikula <jani.nikula@intel.com>
Cc: Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>
Cc: Rob Clark <robdclark@gmail.com>
Cc: Sean Paul <seanpaul@chromium.org>
Cc: Luis Chamberlain <mcgrof@kernel.org>
Fixes: aad0214f3026 ("dyndbg: add DECLARE_DYNDBG_CLASSMAP macro")
Fixes: f158936b60a7 ("drm: POC drm on dyndbg - use in core, 2 helpers, 3 drivers.")
Ref: commit bb2ff6c27bc9 ("drm: Disable dynamic debug as broken")

Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
---
 MAINTAINERS                             |   2 +-
 drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c |  12 +-
 drivers/gpu/drm/display/drm_dp_helper.c |  12 +-
 drivers/gpu/drm/drm_crtc_helper.c       |  12 +-
 drivers/gpu/drm/drm_print.c             |  25 ++--
 drivers/gpu/drm/i915/i915_params.c      |  12 +-
 drivers/gpu/drm/nouveau/nouveau_drm.c   |  12 +-
 include/asm-generic/vmlinux.lds.h       |   1 +
 include/drm/drm_print.h                 |  10 +-
 include/linux/dynamic_debug.h           |  53 +++++--
 kernel/module/main.c                    |   3 +
 lib/Kconfig.debug                       |  22 ++-
 lib/Makefile                            |   3 +
 lib/dynamic_debug.c                     | 183 +++++++++++++++++++++---
 lib/test_dynamic_debug.c                | 127 ++++++++++------
 lib/test_dynamic_debug_submod.c         |  10 ++
 16 files changed, 346 insertions(+), 153 deletions(-)
 create mode 100644 lib/test_dynamic_debug_submod.c

diff --git a/MAINTAINERS b/MAINTAINERS
index 6c4cce45a09d..aa09ac8dbb39 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -7302,7 +7302,7 @@ M:	Jim Cromie <jim.cromie@gmail.com>
 S:	Maintained
 F:	include/linux/dynamic_debug.h
 F:	lib/dynamic_debug.c
-F:	lib/test_dynamic_debug.c
+F:	lib/test_dynamic_debug*.c
 
 DYNAMIC INTERRUPT MODERATION
 M:	Tal Gilboa <talgi@nvidia.com>
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c
index 81edf66dbea8..efba99c9393e 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c
@@ -197,17 +197,7 @@ int amdgpu_user_partt_mode = AMDGPU_AUTO_COMPUTE_PARTITION_MODE;
 
 static void amdgpu_drv_delayed_reset_work_handler(struct work_struct *work);
 
-DECLARE_DYNDBG_CLASSMAP(drm_debug_classes, DD_CLASS_TYPE_DISJOINT_BITS, 0,
-			"DRM_UT_CORE",
-			"DRM_UT_DRIVER",
-			"DRM_UT_KMS",
-			"DRM_UT_PRIME",
-			"DRM_UT_ATOMIC",
-			"DRM_UT_VBL",
-			"DRM_UT_STATE",
-			"DRM_UT_LEASE",
-			"DRM_UT_DP",
-			"DRM_UT_DRMRES");
+DRM_CLASSMAP_USE(drm_debug_classes);
 
 struct amdgpu_mgpu_info mgpu_info = {
 	.mutex = __MUTEX_INITIALIZER(mgpu_info.mutex),
diff --git a/drivers/gpu/drm/display/drm_dp_helper.c b/drivers/gpu/drm/display/drm_dp_helper.c
index e6a78fd32380..d97de1a27939 100644
--- a/drivers/gpu/drm/display/drm_dp_helper.c
+++ b/drivers/gpu/drm/display/drm_dp_helper.c
@@ -41,17 +41,7 @@
 
 #include "drm_dp_helper_internal.h"
 
-DECLARE_DYNDBG_CLASSMAP(drm_debug_classes, DD_CLASS_TYPE_DISJOINT_BITS, 0,
-			"DRM_UT_CORE",
-			"DRM_UT_DRIVER",
-			"DRM_UT_KMS",
-			"DRM_UT_PRIME",
-			"DRM_UT_ATOMIC",
-			"DRM_UT_VBL",
-			"DRM_UT_STATE",
-			"DRM_UT_LEASE",
-			"DRM_UT_DP",
-			"DRM_UT_DRMRES");
+DRM_CLASSMAP_USE(drm_debug_classes);
 
 struct dp_aux_backlight {
 	struct backlight_device *base;
diff --git a/drivers/gpu/drm/drm_crtc_helper.c b/drivers/gpu/drm/drm_crtc_helper.c
index a209659a996c..fef4662d5f1f 100644
--- a/drivers/gpu/drm/drm_crtc_helper.c
+++ b/drivers/gpu/drm/drm_crtc_helper.c
@@ -50,17 +50,7 @@
 
 #include "drm_crtc_helper_internal.h"
 
-DECLARE_DYNDBG_CLASSMAP(drm_debug_classes, DD_CLASS_TYPE_DISJOINT_BITS, 0,
-			"DRM_UT_CORE",
-			"DRM_UT_DRIVER",
-			"DRM_UT_KMS",
-			"DRM_UT_PRIME",
-			"DRM_UT_ATOMIC",
-			"DRM_UT_VBL",
-			"DRM_UT_STATE",
-			"DRM_UT_LEASE",
-			"DRM_UT_DP",
-			"DRM_UT_DRMRES");
+DRM_CLASSMAP_USE(drm_debug_classes);
 
 /**
  * DOC: overview
diff --git a/drivers/gpu/drm/drm_print.c b/drivers/gpu/drm/drm_print.c
index 5b93c11895bb..dabcfa0dd279 100644
--- a/drivers/gpu/drm/drm_print.c
+++ b/drivers/gpu/drm/drm_print.c
@@ -55,18 +55,19 @@ MODULE_PARM_DESC(debug, "Enable debug output, where each bit enables a debug cat
 #if !defined(CONFIG_DRM_USE_DYNAMIC_DEBUG)
 module_param_named(debug, __drm_debug, ulong, 0600);
 #else
-/* classnames must match vals of enum drm_debug_category */
-DECLARE_DYNDBG_CLASSMAP(drm_debug_classes, DD_CLASS_TYPE_DISJOINT_BITS, 0,
-			"DRM_UT_CORE",
-			"DRM_UT_DRIVER",
-			"DRM_UT_KMS",
-			"DRM_UT_PRIME",
-			"DRM_UT_ATOMIC",
-			"DRM_UT_VBL",
-			"DRM_UT_STATE",
-			"DRM_UT_LEASE",
-			"DRM_UT_DP",
-			"DRM_UT_DRMRES");
+/* classnames must match value-symbols of enum drm_debug_category */
+DRM_CLASSMAP_DEFINE(drm_debug_classes, DD_CLASS_TYPE_DISJOINT_BITS,
+		    DRM_UT_CORE,
+		    "DRM_UT_CORE",
+		    "DRM_UT_DRIVER",
+		    "DRM_UT_KMS",
+		    "DRM_UT_PRIME",
+		    "DRM_UT_ATOMIC",
+		    "DRM_UT_VBL",
+		    "DRM_UT_STATE",
+		    "DRM_UT_LEASE",
+		    "DRM_UT_DP",
+		    "DRM_UT_DRMRES");
 
 static struct ddebug_class_param drm_debug_bitmap = {
 	.bits = &__drm_debug,
diff --git a/drivers/gpu/drm/i915/i915_params.c b/drivers/gpu/drm/i915/i915_params.c
index 0a171b57fd8f..d870e15da21c 100644
--- a/drivers/gpu/drm/i915/i915_params.c
+++ b/drivers/gpu/drm/i915/i915_params.c
@@ -29,17 +29,7 @@
 #include "i915_params.h"
 #include "i915_drv.h"
 
-DECLARE_DYNDBG_CLASSMAP(drm_debug_classes, DD_CLASS_TYPE_DISJOINT_BITS, 0,
-			"DRM_UT_CORE",
-			"DRM_UT_DRIVER",
-			"DRM_UT_KMS",
-			"DRM_UT_PRIME",
-			"DRM_UT_ATOMIC",
-			"DRM_UT_VBL",
-			"DRM_UT_STATE",
-			"DRM_UT_LEASE",
-			"DRM_UT_DP",
-			"DRM_UT_DRMRES");
+DRM_CLASSMAP_USE(drm_debug_classes);
 
 #define i915_param_named(name, T, perm, desc) \
 	module_param_named(name, i915_modparams.name, T, perm); \
diff --git a/drivers/gpu/drm/nouveau/nouveau_drm.c b/drivers/gpu/drm/nouveau/nouveau_drm.c
index 4396f501b16a..65006274be9d 100644
--- a/drivers/gpu/drm/nouveau/nouveau_drm.c
+++ b/drivers/gpu/drm/nouveau/nouveau_drm.c
@@ -72,17 +72,7 @@
 #include "nouveau_uvmm.h"
 #include "nouveau_sched.h"
 
-DECLARE_DYNDBG_CLASSMAP(drm_debug_classes, DD_CLASS_TYPE_DISJOINT_BITS, 0,
-			"DRM_UT_CORE",
-			"DRM_UT_DRIVER",
-			"DRM_UT_KMS",
-			"DRM_UT_PRIME",
-			"DRM_UT_ATOMIC",
-			"DRM_UT_VBL",
-			"DRM_UT_STATE",
-			"DRM_UT_LEASE",
-			"DRM_UT_DP",
-			"DRM_UT_DRMRES");
+DRM_CLASSMAP_USE(drm_debug_classes);
 
 MODULE_PARM_DESC(config, "option string to pass to driver core");
 static char *nouveau_config;
diff --git a/include/asm-generic/vmlinux.lds.h b/include/asm-generic/vmlinux.lds.h
index 67d8dd2f1bde..5451f926a753 100644
--- a/include/asm-generic/vmlinux.lds.h
+++ b/include/asm-generic/vmlinux.lds.h
@@ -366,6 +366,7 @@
 	/* implement dynamic printk debug */				\
 	. = ALIGN(8);							\
 	BOUNDED_SECTION_BY(__dyndbg_classes, ___dyndbg_classes)		\
+	BOUNDED_SECTION_BY(__dyndbg_class_users, ___dyndbg_class_users)	\
 	BOUNDED_SECTION_BY(__dyndbg, ___dyndbg)				\
 	LIKELY_PROFILE()		       				\
 	BRANCH_PROFILE()						\
diff --git a/include/drm/drm_print.h b/include/drm/drm_print.h
index a93a387f8a1a..706afc97c79c 100644
--- a/include/drm/drm_print.h
+++ b/include/drm/drm_print.h
@@ -276,7 +276,7 @@ static inline struct drm_printer drm_err_printer(const char *prefix)
  *
  */
 enum drm_debug_category {
-	/* These names must match those in DYNAMIC_DEBUG_CLASSBITS */
+	/* Keep DRM_CLASSMAP_DEFINE args in sync with any changes here */
 	/**
 	 * @DRM_UT_CORE: Used in the generic drm code: drm_ioctl.c, drm_mm.c,
 	 * drm_memory.c, ...
@@ -321,6 +321,14 @@ enum drm_debug_category {
 	DRM_UT_DRMRES
 };
 
+#ifdef CONFIG_DRM_USE_DYNAMIC_DEBUG
+#define DRM_CLASSMAP_DEFINE(...) DYNDBG_CLASSMAP_DEFINE(__VA_ARGS__)
+#define DRM_CLASSMAP_USE(name)   DYNDBG_CLASSMAP_USE(name)
+#else
+#define DRM_CLASSMAP_DEFINE(...)
+#define DRM_CLASSMAP_USE(name)
+#endif
+
 static inline bool drm_debug_enabled_raw(enum drm_debug_category category)
 {
 	return unlikely(__drm_debug & BIT(category));
diff --git a/include/linux/dynamic_debug.h b/include/linux/dynamic_debug.h
index 8eaf8eabdc8d..1b027be2cdc4 100644
--- a/include/linux/dynamic_debug.h
+++ b/include/linux/dynamic_debug.h
@@ -58,7 +58,7 @@ struct _ddebug {
 #endif
 } __attribute__((aligned(8)));
 
-enum class_map_type {
+enum ddebug_class_map_type {
 	DD_CLASS_TYPE_DISJOINT_BITS,
 	/**
 	 * DD_CLASS_TYPE_DISJOINT_BITS: classes are independent, mapped to bits[0..N].
@@ -72,24 +72,27 @@ enum class_map_type {
 };
 
 struct ddebug_class_map {
-	struct module *mod;
-	const char *mod_name;	/* needed for builtins */
+	const struct module *mod;		/* NULL for builtins */
+	const char *mod_name;
 	const char **class_names;
 	const int length;
 	const int base;		/* index of 1st .class_id, allows split/shared space */
-	enum class_map_type map_type;
+	enum ddebug_class_map_type map_type;
 };
 
 /**
- * DECLARE_DYNDBG_CLASSMAP - declare classnames known by a module
- * @_var:   a struct ddebug_class_map, passed to module_param_cb
- * @_type:  enum class_map_type, chooses bits/verbose, numeric/symbolic
- * @_base:  offset of 1st class-name. splits .class_id space
- * @classes: class-names used to control class'd prdbgs
+ * DYNDBG_CLASSMAP_DEFINE - define a set of debug-classes used by a module.
+ * @_var:   name of the classmap, exported for other modules coordinated use.
+ * @_type:  enum ddebug_class_map_type, chooses bits/verbose, numeric/names.
+ * @_base:  offset of 1st class-name, used to share 0..62 classid space
+ * @classes: vals are stringified enum-vals, like DRM_UT_*
+ *
+ * Defines and exports a struct ddebug_class_map whose @classes are
+ * used to validate a "class FOO .." >control command on the module
  */
-#define DECLARE_DYNDBG_CLASSMAP(_var, _maptype, _base, ...)		\
-	static const char *_var##_classnames[] = { __VA_ARGS__ };	\
-	static struct ddebug_class_map __aligned(8) __used		\
+#define DYNDBG_CLASSMAP_DEFINE(_var, _maptype, _base, ...)		\
+	const char *_var##_classnames[] = { __VA_ARGS__ };		\
+	struct ddebug_class_map __aligned(8) __used			\
 		__section("__dyndbg_classes") _var = {			\
 		.mod = THIS_MODULE,					\
 		.mod_name = KBUILD_MODNAME,				\
@@ -97,14 +100,40 @@ struct ddebug_class_map {
 		.map_type = _maptype,					\
 		.length = ARRAY_SIZE(_var##_classnames),		\
 		.class_names = _var##_classnames,			\
+	};								\
+	EXPORT_SYMBOL(_var)
+
+struct ddebug_class_user {
+	char *user_mod_name;
+	struct ddebug_class_map *map;
+};
+
+/**
+ * DYNDBG_CLASSMAP_USE - refer to a classmap, DEFINEd elsewhere.
+ * @_var: name of the exported classmap var
+ *
+ * This registers a module's use of another module's classmap defn, so
+ * dyndbg can authorize "class DRM_CORE ..." >control commands upon
+ * this module.
+ */
+#define DYNDBG_CLASSMAP_USE(_var)					\
+	DYNDBG_CLASSMAP_USE_(_var, __UNIQUE_ID(ddebug_class_user))
+#define DYNDBG_CLASSMAP_USE_(_var, _uname)				\
+	extern struct ddebug_class_map _var;				\
+	static struct ddebug_class_user __aligned(8) __used		\
+	__section("__dyndbg_class_users") _uname = {			\
+		.user_mod_name = KBUILD_MODNAME,			\
+		.map = &_var,						\
 	}
 
 /* encapsulate linker provided built-in (or module) dyndbg data */
 struct _ddebug_info {
 	struct _ddebug *descs;
 	struct ddebug_class_map *classes;
+	struct ddebug_class_user *class_users;
 	unsigned int num_descs;
 	unsigned int num_classes;
+	unsigned int num_class_users;
 };
 
 struct ddebug_class_param {
diff --git a/kernel/module/main.c b/kernel/module/main.c
index 98fedfdb8db5..6b0b0d82b5ab 100644
--- a/kernel/module/main.c
+++ b/kernel/module/main.c
@@ -2214,6 +2214,9 @@ static int find_module_sections(struct module *mod, struct load_info *info)
 	mod->dyndbg_info.classes = section_objs(info, "__dyndbg_classes",
 						sizeof(*mod->dyndbg_info.classes),
 						&mod->dyndbg_info.num_classes);
+	mod->dyndbg_info.class_users = section_objs(info, "__dyndbg_class_users",
+						    sizeof(*mod->dyndbg_info.class_users),
+						   &mod->dyndbg_info.num_class_users);
 #endif
 
 	return 0;
diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index fa307f93fa2e..d015687e845c 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -2808,12 +2808,24 @@ config TEST_STATIC_KEYS
 	  If unsure, say N.
 
 config TEST_DYNAMIC_DEBUG
-	tristate "Test DYNAMIC_DEBUG"
-	depends on DYNAMIC_DEBUG
+	tristate "Build test-dynamic-debug module"
+	depends on DYNAMIC_DEBUG || DYNAMIC_DEBUG_CORE
+	help
+	  This module works/demo's the dyndbg's classmap API, by
+	  creating 2 classes: a DISJOINT classmap (like DRM.debug)
+	  and a LEVELS/VERBOSE classmap (like verbose2 > verbose1).
+
+	  If unsure, say N.
+
+config TEST_DYNAMIC_DEBUG_SUBMOD
+	tristate "Build test-dynamic-debug submodule"
+	default m
+	depends on DYNAMIC_DEBUG || DYNAMIC_DEBUG_CORE
+	depends on TEST_DYNAMIC_DEBUG
 	help
-	  This module registers a tracer callback to count enabled
-	  pr_debugs in a 'do_debugging' function, then alters their
-	  enablements, calls the function, and compares counts.
+	  This sub-module depends upon a classmap defined in the
+	  super-module.  It it independently settable=m/y to allow all
+	  proper combinations of parent=y/m submod=y/m
 
 	  If unsure, say N.
 
diff --git a/lib/Makefile b/lib/Makefile
index 740109b6e2c8..2d4c7b689bbf 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -81,6 +81,7 @@ obj-$(CONFIG_TEST_USER_COPY) += test_user_copy.o
 obj-$(CONFIG_TEST_STATIC_KEYS) += test_static_keys.o
 obj-$(CONFIG_TEST_STATIC_KEYS) += test_static_key_base.o
 obj-$(CONFIG_TEST_DYNAMIC_DEBUG) += test_dynamic_debug.o
+obj-$(CONFIG_TEST_DYNAMIC_DEBUG_SUBMOD) += test_dynamic_debug_submod.o
 obj-$(CONFIG_TEST_PRINTF) += test_printf.o
 obj-$(CONFIG_TEST_SCANF) += test_scanf.o
 
@@ -240,6 +241,8 @@ obj-$(CONFIG_HAVE_ARCH_TRACEHOOK) += syscall.o
 obj-$(CONFIG_DYNAMIC_DEBUG_CORE) += dynamic_debug.o
 #ensure exported functions have prototypes
 CFLAGS_dynamic_debug.o := -DDYNAMIC_DEBUG_MODULE
+CFLAGS_test_dynamic_debug.o := -DDYNAMIC_DEBUG_MODULE
+CFLAGS_test_dynamic_debug_submod.o := -DDYNAMIC_DEBUG_MODULE
 
 obj-$(CONFIG_SYMBOLIC_ERRNAME) += errname.o
 
diff --git a/lib/dynamic_debug.c b/lib/dynamic_debug.c
index 91c8b67fd8f8..be49e104ec76 100644
--- a/lib/dynamic_debug.c
+++ b/lib/dynamic_debug.c
@@ -43,13 +43,16 @@ extern struct _ddebug __start___dyndbg[];
 extern struct _ddebug __stop___dyndbg[];
 extern struct ddebug_class_map __start___dyndbg_classes[];
 extern struct ddebug_class_map __stop___dyndbg_classes[];
+extern struct ddebug_class_user __start___dyndbg_class_users[];
+extern struct ddebug_class_user __stop___dyndbg_class_users[];
 
 struct ddebug_table {
 	struct list_head link;
 	const char *mod_name;
 	struct _ddebug *ddebugs;
 	struct ddebug_class_map *classes;
-	unsigned int num_ddebugs, num_classes;
+	struct ddebug_class_user *class_users;
+	unsigned int num_ddebugs, num_classes, num_class_users;
 };
 
 struct ddebug_query {
@@ -148,21 +151,39 @@ static void vpr_info_dq(const struct ddebug_query *query, const char *msg)
 		  query->first_lineno, query->last_lineno, query->class_string);
 }
 
+#define vpr_dt_info(dt_p, msg_p, ...) ({				\
+	struct ddebug_table const *_dt = dt_p;				\
+	v2pr_info(msg_p " module:%s nd:%d nc:%d nu:%d\n", ##__VA_ARGS__, \
+		  _dt->mod_name, _dt->num_ddebugs, _dt->num_classes,	\
+		  _dt->num_class_users);				\
+	})
+
 #define __outvar /* filled by callee */
 static struct ddebug_class_map *ddebug_find_valid_class(struct ddebug_table const *dt,
 							const char *class_string,
 							__outvar int *class_id)
 {
 	struct ddebug_class_map *map;
+	struct ddebug_class_user *cli;
 	int i, idx;
 
-	for (map = dt->classes, i = 0; i < dt->num_classes; i++, map++) {
+	for (i = 0, map = dt->classes; i < dt->num_classes; i++, map++) {
 		idx = match_string(map->class_names, map->length, class_string);
 		if (idx >= 0) {
 			*class_id = idx + map->base;
+			vpr_dt_info(dt, "good-class: %s.%s ", map->mod_name, class_string);
 			return map;
 		}
 	}
+	for (i = 0, cli = dt->class_users; i < dt->num_class_users; i++, cli++) {
+		idx = match_string(cli->map->class_names, cli->map->length, class_string);
+		if (idx >= 0) {
+			*class_id = idx + cli->map->base;
+			vpr_dt_info(dt, "class-ref: %s.%s ",
+				    cli->user_mod_name, class_string);
+			return cli->map;
+		}
+	}
 	*class_id = -ENOENT;
 	return NULL;
 }
@@ -555,7 +576,7 @@ static int ddebug_exec_query(char *query_string, const char *modname)
 
 /* handle multiple queries in query string, continue on error, return
    last error or number of matching callsites.  Module name is either
-   in param (for boot arg) or perhaps in query string.
+   in the modname arg (for boot args) or perhaps in query string.
 */
 static int ddebug_exec_queries(char *query, const char *modname)
 {
@@ -684,12 +705,12 @@ static int param_set_dyndbg_module_classes(const char *instr,
 }
 
 /**
- * param_set_dyndbg_classes - class FOO >control
+ * param_set_dyndbg_classes - set all classes in a classmap
  * @instr: string echo>d to sysfs, input depends on map_type
- * @kp:    kp->arg has state: bits/lvl, map, map_type
+ * @kp:    kp->arg has state: bits/lvl, classmap, map_type
  *
- * Enable/disable prdbgs by their class, as given in the arguments to
- * DECLARE_DYNDBG_CLASSMAP.  For LEVEL map-types, enforce relative
+ * For all classes in the classmap, enable/disable them per the input
+ * (depending on map_type).  For LEVEL map-types, enforce relative
  * levels by bitpos.
  *
  * Returns: 0 or <0 if error.
@@ -1034,12 +1055,17 @@ static void *ddebug_proc_next(struct seq_file *m, void *p, loff_t *pos)
 static const char *ddebug_class_name(struct ddebug_table *dt, struct _ddebug *dp)
 {
 	struct ddebug_class_map *map = dt->classes;
+	struct ddebug_class_user *cli = dt->class_users;
 	int i;
 
 	for (i = 0; i < dt->num_classes; i++, map++)
 		if (class_in_range(dp->class_id, map))
 			return map->class_names[dp->class_id - map->base];
 
+	for (i = 0; i < dt->num_class_users; i++, cli++)
+		if (class_in_range(dp->class_id, cli->map))
+			return cli->map->class_names[dp->class_id - cli->map->base];
+
 	return NULL;
 }
 
@@ -1120,31 +1146,133 @@ static const struct proc_ops proc_fops = {
 	.proc_write = ddebug_proc_write
 };
 
+static const char * const ddebug_classmap_typenames[] = {
+	"DISJOINT_BITS", "LEVEL_NUM", "DISJOINT_NAMES", "LEVEL_NAMES"
+};
+
+#define vpr_cm_info(cm_p, msg_p, ...) ({				\
+	struct ddebug_class_map const *_cm = cm_p;			\
+	v2pr_info(msg_p " module:%s base:%d len:%d type:%s\n", ##__VA_ARGS__, \
+		  _cm->mod_name, _cm->base, _cm->length,		\
+		  ddebug_classmap_typenames[_cm->map_type]);		\
+	})
+
+static void ddebug_sync_classbits(const struct ddebug_class_param *dcp, const char *modname)
+{
+	/* clamp initial bitvec, mask off hi-bits */
+	if (*dcp->bits & ~CLASSMAP_BITMASK(dcp->map->length)) {
+		*dcp->bits &= CLASSMAP_BITMASK(dcp->map->length);
+		v2pr_info("preset classbits: %lx\n", *dcp->bits);
+	}
+	/* force class'd prdbgs (in USEr module) to match (DEFINEr module) class-param */
+	ddebug_apply_class_bitmap(dcp, dcp->bits, ~0, modname);
+	ddebug_apply_class_bitmap(dcp, dcp->bits, 0, modname);
+}
+
+static void ddebug_match_apply_kparam(const struct kernel_param *kp,
+				      const struct ddebug_class_map *map,
+				      const char *modnm)
+{
+	struct ddebug_class_param *dcp;
+
+	if (kp->ops != &param_ops_dyndbg_classes)
+		return;
+
+	dcp = (struct ddebug_class_param *)kp->arg;
+
+	if (map == dcp->map) {
+		v2pr_info("found kp:%s =0x%lx", kp->name, *dcp->bits);
+		vpr_cm_info(map, "mapped to:");
+		ddebug_sync_classbits(dcp, modnm);
+	}
+}
+
+static void ddebug_apply_params(const struct ddebug_class_map *cm, const char *modnm)
+{
+	const struct kernel_param *kp;
+#if IS_ENABLED(CONFIG_MODULES)
+	int i;
+
+	if (cm->mod) {
+		vpr_cm_info(cm, "loaded class:");
+		for (i = 0, kp = cm->mod->kp; i < cm->mod->num_kp; i++, kp++)
+			ddebug_match_apply_kparam(kp, cm, modnm);
+	}
+#endif
+	if (!cm->mod) {
+		vpr_cm_info(cm, "builtin class:");
+		for (kp = __start___param; kp < __stop___param; kp++)
+			ddebug_match_apply_kparam(kp, cm, modnm);
+	}
+}
+
+/*
+ * Find this module's classmaps in a sub/whole-range of the builtin/
+ * modular classmap vector/section.  Save the start and length of the
+ * subrange at its edges.
+ */
 static void ddebug_attach_module_classes(struct ddebug_table *dt, struct _ddebug_info *di)
 {
 	struct ddebug_class_map *cm;
 	int i, nc = 0;
 
-	/*
-	 * Find this module's classmaps in a subrange/wholerange of
-	 * the builtin/modular classmap vector/section.  Save the start
-	 * and length of the subrange at its edges.
-	 */
-	for (cm = di->classes, i = 0; i < di->num_classes; i++, cm++) {
+	for (i = 0, cm = di->classes; i < di->num_classes; i++, cm++) {
 
 		if (!strcmp(cm->mod_name, dt->mod_name)) {
-			if (!nc) {
-				v2pr_info("start subrange, class[%d]: module:%s base:%d len:%d ty:%d\n",
-					  i, cm->mod_name, cm->base, cm->length, cm->map_type);
+			vpr_cm_info(cm, "classes[%d]:", i);
+			if (!nc++)
 				dt->classes = cm;
-			}
-			nc++;
 		}
 	}
-	if (nc) {
-		dt->num_classes = nc;
-		vpr_info("module:%s attached %d classes\n", dt->mod_name, nc);
+	if (!nc)
+		return;
+
+	vpr_info("module:%s attached %d classes\n", dt->mod_name, nc);
+	dt->num_classes = nc;
+
+	for (i = 0, cm = dt->classes; i < dt->num_classes; i++, cm++)
+		ddebug_apply_params(cm, cm->mod_name);
+}
+
+/*
+ * propagates class-params thru their classmaps to class-users.  this
+ * means a query against the dt/module, which means it must be on the
+ * list to be seen by ddebug_change.
+ */
+static void ddebug_attach_user_module_classes(struct ddebug_table *dt,
+					      const struct _ddebug_info *di)
+{
+	struct ddebug_class_user *cli;
+	int i, nc = 0;
+
+	/*
+	 * For builtins: scan the array, find start/length of this
+	 * module's refs, save to dt.  For loadables, this is the
+	 * whole array.
+	 */
+	for (i = 0, cli = di->class_users; i < di->num_class_users; i++, cli++) {
+
+		if (WARN_ON(!cli || !cli->map || !cli->user_mod_name))
+			continue;
+
+		if (!strcmp(cli->user_mod_name, dt->mod_name)) {
+
+			vpr_cm_info(cli->map, "class_ref[%d] %s -> %s", i,
+				    cli->user_mod_name, cli->map->mod_name);
+			if (!nc++)
+				dt->class_users = cli;
+		}
 	}
+	if (!nc)
+		return;
+
+	dt->num_class_users = nc;
+
+	/* now iterate dt */
+	for (i = 0, cli = dt->class_users; i < dt->num_class_users; i++, cli++)
+		ddebug_apply_params(cli->map, cli->user_mod_name);
+
+	vpr_dt_info(dt, "attach-client-module: ");
 }
 
 /*
@@ -1154,6 +1282,8 @@ static void ddebug_attach_module_classes(struct ddebug_table *dt, struct _ddebug
 static int ddebug_add_module(struct _ddebug_info *di, const char *modname)
 {
 	struct ddebug_table *dt;
+	struct _ddebug *iter;
+	int i, class_ct = 0;
 
 	if (!di->num_descs)
 		return 0;
@@ -1177,13 +1307,20 @@ static int ddebug_add_module(struct _ddebug_info *di, const char *modname)
 
 	INIT_LIST_HEAD(&dt->link);
 
-	if (di->classes && di->num_classes)
+	for_each_boxed_vector(di, descs, num_descs, i, iter)
+		if (iter->class_id != _DPRINTK_CLASS_DFLT)
+			class_ct++;
+
+	if (class_ct && di->num_classes)
 		ddebug_attach_module_classes(dt, di);
 
 	mutex_lock(&ddebug_lock);
 	list_add_tail(&dt->link, &ddebug_tables);
 	mutex_unlock(&ddebug_lock);
 
+	if (class_ct && di->num_class_users)
+		ddebug_attach_user_module_classes(dt, di);
+
 	vpr_info("%3u debug prints in module %s\n", di->num_descs, modname);
 	return 0;
 }
@@ -1333,8 +1470,10 @@ static int __init dynamic_debug_init(void)
 	struct _ddebug_info di = {
 		.descs = __start___dyndbg,
 		.classes = __start___dyndbg_classes,
+		.class_users = __start___dyndbg_class_users,
 		.num_descs = __stop___dyndbg - __start___dyndbg,
 		.num_classes = __stop___dyndbg_classes - __start___dyndbg_classes,
+		.num_class_users = __stop___dyndbg_class_users - __start___dyndbg_class_users,
 	};
 
 #ifdef CONFIG_MODULES
diff --git a/lib/test_dynamic_debug.c b/lib/test_dynamic_debug.c
index 229eaadee838..23967071b60f 100644
--- a/lib/test_dynamic_debug.c
+++ b/lib/test_dynamic_debug.c
@@ -6,11 +6,15 @@
  *      Jim Cromie	<jim.cromie@gmail.com>
  */
 
-#define pr_fmt(fmt) "test_dd: " fmt
+#if defined(TEST_DYNAMIC_DEBUG_SUBMOD)
+  #define pr_fmt(fmt) "test_dd_submod: " fmt
+#else
+  #define pr_fmt(fmt) "test_dd: " fmt
+#endif
 
 #include <linux/module.h>
 
-/* run tests by reading or writing sysfs node: do_prints */
+/* re-gen output by reading or writing sysfs node: do_prints */
 
 static void do_prints(void); /* device under test */
 static int param_set_do_prints(const char *instr, const struct kernel_param *kp)
@@ -29,24 +33,39 @@ static const struct kernel_param_ops param_ops_do_prints = {
 };
 module_param_cb(do_prints, &param_ops_do_prints, NULL, 0600);
 
-/*
- * Using the CLASSMAP api:
- * - classmaps must have corresponding enum
- * - enum symbols must match/correlate with class-name strings in the map.
- * - base must equal enum's 1st value
- * - multiple maps must set their base to share the 0-30 class_id space !!
- *   (build-bug-on tips welcome)
- * Additionally, here:
- * - tie together sysname, mapname, bitsname, flagsname
- */
-#define DD_SYS_WRAP(_model, _flags)					\
-	static unsigned long bits_##_model;				\
-	static struct ddebug_class_param _flags##_model = {		\
+#define CLASSMAP_BITMASK(width, base) (((1UL << (width)) - 1) << base)
+
+/* sysfs param wrapper, proto-API */
+#define DYNDBG_CLASSMAP_PARAM_(_model, _flags, _init)			\
+	static unsigned long bits_##_model = _init;			\
+	static struct ddebug_class_param _flags##_##_model = {		\
 		.bits = &bits_##_model,					\
 		.flags = #_flags,					\
 		.map = &map_##_model,					\
 	};								\
-	module_param_cb(_flags##_##_model, &param_ops_dyndbg_classes, &_flags##_model, 0600)
+	module_param_cb(_flags##_##_model, &param_ops_dyndbg_classes,	\
+			&_flags##_##_model, 0600)
+#ifdef DEBUG
+#define DYNDBG_CLASSMAP_PARAM(_model, _flags)  DYNDBG_CLASSMAP_PARAM_(_model, _flags, ~0)
+#else
+#define DYNDBG_CLASSMAP_PARAM(_model, _flags)  DYNDBG_CLASSMAP_PARAM_(_model, _flags, 0)
+#endif
+
+/*
+ * Demonstrate/test all 4 class-typed classmaps with a sys-param.
+ *
+ * Each is 3 part: client-enum decl, _DEFINE, _PARAM.
+ * Declare them in blocks to show patterns of use (repetitions and
+ * changes) within each.
+ *
+ * 1st, dyndbg expects a client-provided enum-type as source of
+ * category/classid truth.  DRM has DRM_UT_<CORE,DRIVER,KMS,etc>.
+ *
+ * Modules with multiple CLASSMAPS must have enums with distinct
+ * value-ranges, arranged below with explicit enum_sym = X inits.
+ *
+ * Declare all 4 enums now, for different types
+ */
 
 /* numeric input, independent bits */
 enum cat_disjoint_bits {
@@ -60,40 +79,57 @@ enum cat_disjoint_bits {
 	D2_LEASE,
 	D2_DP,
 	D2_DRMRES };
-DECLARE_DYNDBG_CLASSMAP(map_disjoint_bits, DD_CLASS_TYPE_DISJOINT_BITS, 0,
-			"D2_CORE",
-			"D2_DRIVER",
-			"D2_KMS",
-			"D2_PRIME",
-			"D2_ATOMIC",
-			"D2_VBL",
-			"D2_STATE",
-			"D2_LEASE",
-			"D2_DP",
-			"D2_DRMRES");
-DD_SYS_WRAP(disjoint_bits, p);
-DD_SYS_WRAP(disjoint_bits, T);
-
-/* symbolic input, independent bits */
-enum cat_disjoint_names { LOW = 10, MID, HI };
-DECLARE_DYNDBG_CLASSMAP(map_disjoint_names, DD_CLASS_TYPE_DISJOINT_NAMES, 10,
-			"LOW", "MID", "HI");
-DD_SYS_WRAP(disjoint_names, p);
-DD_SYS_WRAP(disjoint_names, T);
 
 /* numeric verbosity, V2 > V1 related */
 enum cat_level_num { V0 = 14, V1, V2, V3, V4, V5, V6, V7 };
-DECLARE_DYNDBG_CLASSMAP(map_level_num, DD_CLASS_TYPE_LEVEL_NUM, 14,
-		       "V0", "V1", "V2", "V3", "V4", "V5", "V6", "V7");
-DD_SYS_WRAP(level_num, p);
-DD_SYS_WRAP(level_num, T);
 
-/* symbolic verbosity */
+/* named-symbolic input, independent bits */
+enum cat_disjoint_names { LOW = 10, MID, HI };
+
+/* named-symbolic verbosity */
 enum cat_level_names { L0 = 22, L1, L2, L3, L4, L5, L6, L7 };
-DECLARE_DYNDBG_CLASSMAP(map_level_names, DD_CLASS_TYPE_LEVEL_NAMES, 22,
-			"L0", "L1", "L2", "L3", "L4", "L5", "L6", "L7");
-DD_SYS_WRAP(level_names, p);
-DD_SYS_WRAP(level_names, T);
+
+/* recapitulate DRM's parent(drm.ko) <-- _submod(drivers,helpers) */
+#if !defined(TEST_DYNAMIC_DEBUG_SUBMOD)
+/*
+ * In single user, or parent / coordinator (drm.ko) modules, define
+ * classmaps on the client enums above, and then declares the PARAMS
+ * ref'g the classmaps.  Each is exported.
+ */
+DYNDBG_CLASSMAP_DEFINE(map_disjoint_bits, DD_CLASS_TYPE_DISJOINT_BITS,
+		       D2_CORE,
+		       "D2_CORE",
+		       "D2_DRIVER",
+		       "D2_KMS",
+		       "D2_PRIME",
+		       "D2_ATOMIC",
+		       "D2_VBL",
+		       "D2_STATE",
+		       "D2_LEASE",
+		       "D2_DP",
+		       "D2_DRMRES");
+
+DYNDBG_CLASSMAP_DEFINE(map_level_num, DD_CLASS_TYPE_LEVEL_NUM,
+		       V0, "V0", "V1", "V2", "V3", "V4", "V5", "V6", "V7");
+
+/*
+ * now add the sysfs-params
+ */
+
+DYNDBG_CLASSMAP_PARAM(disjoint_bits, p);
+DYNDBG_CLASSMAP_PARAM(level_num, p);
+
+#else /* TEST_DYNAMIC_DEBUG_SUBMOD */
+
+/*
+ * in submod/drm-drivers, use the classmaps defined in top/parent
+ * module above.
+ */
+
+DYNDBG_CLASSMAP_USE(map_disjoint_bits);
+DYNDBG_CLASSMAP_USE(map_level_num);
+
+#endif
 
 /* stand-in for all pr_debug etc */
 #define prdbg(SYM) __pr_debug_cls(SYM, #SYM " msg\n")
@@ -129,6 +165,7 @@ static void do_levels(void)
 
 static void do_prints(void)
 {
+	pr_debug("do_prints:\n");
 	do_cats();
 	do_levels();
 }
diff --git a/lib/test_dynamic_debug_submod.c b/lib/test_dynamic_debug_submod.c
new file mode 100644
index 000000000000..9a893402ce1a
--- /dev/null
+++ b/lib/test_dynamic_debug_submod.c
@@ -0,0 +1,10 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Kernel module for testing dynamic_debug
+ *
+ * Authors:
+ *      Jim Cromie	<jim.cromie@gmail.com>
+ */
+
+#define TEST_DYNAMIC_DEBUG_SUBMOD
+#include "test_dynamic_debug.c"
-- 
2.41.0

[PATCH v7 15/25] dyndbg: add for_each_boxed_vector

[Jim Cromie]

Add a for_each iterator to walk a counted vector member in a struct
(ie the box), and use it to replace 8 open-coded loops.

Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
---
v5- parens-on-box-force-precedence
---
 lib/dynamic_debug.c | 20 +++++++++++---------
 1 file changed, 11 insertions(+), 9 deletions(-)

diff --git a/lib/dynamic_debug.c b/lib/dynamic_debug.c
index be49e104ec76..c11feca70d6f 100644
--- a/lib/dynamic_debug.c
+++ b/lib/dynamic_debug.c
@@ -158,6 +158,9 @@ static void vpr_info_dq(const struct ddebug_query *query, const char *msg)
 		  _dt->num_class_users);				\
 	})
 
+#define for_each_boxed_vector(_box, _vec, _len, _ct, _curs)		\
+	for (_ct = 0, _curs = (_box)->_vec; _ct < (_box)->_len; _ct++, _curs++)
+
 #define __outvar /* filled by callee */
 static struct ddebug_class_map *ddebug_find_valid_class(struct ddebug_table const *dt,
 							const char *class_string,
@@ -167,7 +170,7 @@ static struct ddebug_class_map *ddebug_find_valid_class(struct ddebug_table cons
 	struct ddebug_class_user *cli;
 	int i, idx;
 
-	for (i = 0, map = dt->classes; i < dt->num_classes; i++, map++) {
+	for_each_boxed_vector(dt, classes, num_classes, i, map) {
 		idx = match_string(map->class_names, map->length, class_string);
 		if (idx >= 0) {
 			*class_id = idx + map->base;
@@ -175,7 +178,7 @@ static struct ddebug_class_map *ddebug_find_valid_class(struct ddebug_table cons
 			return map;
 		}
 	}
-	for (i = 0, cli = dt->class_users; i < dt->num_class_users; i++, cli++) {
+	for_each_boxed_vector(dt, class_users, num_class_users, i, cli) {
 		idx = match_string(cli->map->class_names, cli->map->length, class_string);
 		if (idx >= 0) {
 			*class_id = idx + cli->map->base;
@@ -1058,11 +1061,11 @@ static const char *ddebug_class_name(struct ddebug_table *dt, struct _ddebug *dp
 	struct ddebug_class_user *cli = dt->class_users;
 	int i;
 
-	for (i = 0; i < dt->num_classes; i++, map++)
+	for_each_boxed_vector(dt, classes, num_classes, i, map)
 		if (class_in_range(dp->class_id, map))
 			return map->class_names[dp->class_id - map->base];
 
-	for (i = 0; i < dt->num_class_users; i++, cli++)
+	for_each_boxed_vector(dt, class_users, num_class_users, i, cli)
 		if (class_in_range(dp->class_id, cli->map))
 			return cli->map->class_names[dp->class_id - cli->map->base];
 
@@ -1216,7 +1219,7 @@ static void ddebug_attach_module_classes(struct ddebug_table *dt, struct _ddebug
 	struct ddebug_class_map *cm;
 	int i, nc = 0;
 
-	for (i = 0, cm = di->classes; i < di->num_classes; i++, cm++) {
+	for_each_boxed_vector(di, classes, num_classes, i, cm) {
 
 		if (!strcmp(cm->mod_name, dt->mod_name)) {
 			vpr_cm_info(cm, "classes[%d]:", i);
@@ -1230,7 +1233,7 @@ static void ddebug_attach_module_classes(struct ddebug_table *dt, struct _ddebug
 	vpr_info("module:%s attached %d classes\n", dt->mod_name, nc);
 	dt->num_classes = nc;
 
-	for (i = 0, cm = dt->classes; i < dt->num_classes; i++, cm++)
+	for_each_boxed_vector(di, classes, num_classes, i, cm)
 		ddebug_apply_params(cm, cm->mod_name);
 }
 
@@ -1250,7 +1253,7 @@ static void ddebug_attach_user_module_classes(struct ddebug_table *dt,
 	 * module's refs, save to dt.  For loadables, this is the
 	 * whole array.
 	 */
-	for (i = 0, cli = di->class_users; i < di->num_class_users; i++, cli++) {
+	for_each_boxed_vector(di, class_users, num_class_users, i, cli) {
 
 		if (WARN_ON(!cli || !cli->map || !cli->user_mod_name))
 			continue;
@@ -1268,8 +1271,7 @@ static void ddebug_attach_user_module_classes(struct ddebug_table *dt,
 
 	dt->num_class_users = nc;
 
-	/* now iterate dt */
-	for (i = 0, cli = dt->class_users; i < dt->num_class_users; i++, cli++)
+	for_each_boxed_vector(di, class_users, num_class_users, i, cli)
 		ddebug_apply_params(cli->map, cli->user_mod_name);
 
 	vpr_dt_info(dt, "attach-client-module: ");
-- 
2.41.0

[PATCH v7 16/25] dyndbg: refactor ddebug_classparam_clamp_input

[Jim Cromie]

Extract input validation code, from param_set_dyndbg_module_classes()
(the sys-node >handler) to new: ddebug_classparam_clamp_input(kp),
call it from former.  It takes kernel-param arg, so it can complain
about "foo: bad input".

Reuse ddparam_clamp_input(kp) in ddebug_sync_classbits(),
to validate inputs from parent's params, just like our own.
To support that reuse, alter ddebug_sync_classbits() and caller to
pass kp instead of kp->arg.

Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
---
 lib/dynamic_debug.c | 70 ++++++++++++++++++++++++++++++---------------
 1 file changed, 47 insertions(+), 23 deletions(-)

diff --git a/lib/dynamic_debug.c b/lib/dynamic_debug.c
index c11feca70d6f..17eefb35ac96 100644
--- a/lib/dynamic_debug.c
+++ b/lib/dynamic_debug.c
@@ -656,6 +656,30 @@ static int ddebug_apply_class_bitmap(const struct ddebug_class_param *dcp,
 
 #define CLASSMAP_BITMASK(width) ((1UL << (width)) - 1)
 
+static void ddebug_class_param_clamp_input(unsigned long *inrep, const struct kernel_param *kp)
+{
+	const struct ddebug_class_param *dcp = kp->arg;
+	const struct ddebug_class_map *map = dcp->map;
+
+	switch (map->map_type) {
+	case DD_CLASS_TYPE_DISJOINT_BITS:
+		/* expect bits. mask and warn if too many */
+		if (*inrep & ~CLASSMAP_BITMASK(map->length)) {
+			pr_warn("%s: input: 0x%lx exceeds mask: 0x%lx, masking\n",
+				KP_NAME(kp), *inrep, CLASSMAP_BITMASK(map->length));
+			*inrep &= CLASSMAP_BITMASK(map->length);
+		}
+		break;
+	case DD_CLASS_TYPE_LEVEL_NUM:
+		/* input is bitpos, of highest verbosity to be enabled */
+		if (*inrep > map->length) {
+			pr_warn("%s: level:%ld exceeds max:%d, clamping\n",
+				KP_NAME(kp), *inrep, map->length);
+			*inrep = map->length;
+		}
+		break;
+	}
+}
 static int param_set_dyndbg_module_classes(const char *instr,
 					   const struct kernel_param *kp,
 					   const char *modnm)
@@ -674,26 +698,15 @@ static int param_set_dyndbg_module_classes(const char *instr,
 		pr_err("expecting numeric input, not: %s > %s\n", instr, KP_NAME(kp));
 		return -EINVAL;
 	}
+	ddebug_class_param_clamp_input(&inrep, kp);
 
 	switch (map->map_type) {
 	case DD_CLASS_TYPE_DISJOINT_BITS:
-		/* expect bits. mask and warn if too many */
-		if (inrep & ~CLASSMAP_BITMASK(map->length)) {
-			pr_warn("%s: input: 0x%lx exceeds mask: 0x%lx, masking\n",
-				KP_NAME(kp), inrep, CLASSMAP_BITMASK(map->length));
-			inrep &= CLASSMAP_BITMASK(map->length);
-		}
 		v2pr_info("bits:0x%lx > %s.%s\n", inrep, modnm ?: "*", KP_NAME(kp));
 		totct += ddebug_apply_class_bitmap(dcp, &inrep, *dcp->bits, modnm);
 		*dcp->bits = inrep;
 		break;
 	case DD_CLASS_TYPE_LEVEL_NUM:
-		/* input is bitpos, of highest verbosity to be enabled */
-		if (inrep > map->length) {
-			pr_warn("%s: level:%ld exceeds max:%d, clamping\n",
-				KP_NAME(kp), inrep, map->length);
-			inrep = map->length;
-		}
 		old_bits = CLASSMAP_BITMASK(*dcp->lvl);
 		new_bits = CLASSMAP_BITMASK(inrep);
 		v2pr_info("lvl:%ld bits:0x%lx > %s\n", inrep, new_bits, KP_NAME(kp));
@@ -1160,16 +1173,27 @@ static const char * const ddebug_classmap_typenames[] = {
 		  ddebug_classmap_typenames[_cm->map_type]);		\
 	})
 
-static void ddebug_sync_classbits(const struct ddebug_class_param *dcp, const char *modname)
+static void ddebug_sync_classbits(const struct kernel_param *kp, const char *modname)
 {
-	/* clamp initial bitvec, mask off hi-bits */
-	if (*dcp->bits & ~CLASSMAP_BITMASK(dcp->map->length)) {
-		*dcp->bits &= CLASSMAP_BITMASK(dcp->map->length);
-		v2pr_info("preset classbits: %lx\n", *dcp->bits);
+	struct ddebug_class_param *dcp = kp->arg;
+	unsigned long new_bits;
+
+	ddebug_class_param_clamp_input(dcp->bits, kp);
+
+	switch (dcp->map->map_type) {
+	case DD_CLASS_TYPE_DISJOINT_BITS:
+		v2pr_info("  %s: classbits: 0x%lx\n", KP_NAME(kp), *dcp->bits);
+		ddebug_apply_class_bitmap(dcp, dcp->bits, 0UL, modname);
+		break;
+	case DD_CLASS_TYPE_LEVEL_NUM:
+		new_bits = CLASSMAP_BITMASK(*dcp->lvl);
+		v2pr_info("  %s: lvl:%ld bits:0x%lx\n", KP_NAME(kp), *dcp->lvl, new_bits);
+		ddebug_apply_class_bitmap(dcp, &new_bits, 0UL, modname);
+		break;
+	default:
+		pr_err("bad map type %d\n", dcp->map->map_type);
+		return;
 	}
-	/* force class'd prdbgs (in USEr module) to match (DEFINEr module) class-param */
-	ddebug_apply_class_bitmap(dcp, dcp->bits, ~0, modname);
-	ddebug_apply_class_bitmap(dcp, dcp->bits, 0, modname);
 }
 
 static void ddebug_match_apply_kparam(const struct kernel_param *kp,
@@ -1184,9 +1208,9 @@ static void ddebug_match_apply_kparam(const struct kernel_param *kp,
 	dcp = (struct ddebug_class_param *)kp->arg;
 
 	if (map == dcp->map) {
-		v2pr_info("found kp:%s =0x%lx", kp->name, *dcp->bits);
-		vpr_cm_info(map, "mapped to:");
-		ddebug_sync_classbits(dcp, modnm);
+		v2pr_info(" found kp:%s =0x%lx", kp->name, *dcp->bits);
+		vpr_cm_info(map, "  mapped to:");
+		ddebug_sync_classbits(kp, modnm);
 	}
 }
 
-- 
2.41.0

[PATCH v7 17/25] dyndbg-API: promote DYNDBG_CLASSMAP_PARAM to API

[Jim Cromie]

move macro from test-dynamic-debug.c into header, and refine it.

Distinguish the 2 use cases of DYNDBG_CLASSMAP_PARAM*

1.DYNDBG_CLASSMAP_PARAM_REF
    for DRM, to pass in extern __drm_debug by name.
    dyndbg keeps bits in it, so drm can still use it as before

2.DYNDBG_CLASSMAP_PARAM
    new user (test_dynamic_debug) doesn't need to share state,
    decls a static long unsigned int to store the bitvec.

__DYNDBG_CLASSMAP_PARAM
   bottom layer - allocate,init a ddebug-class-param, module-param-cb.

Also clean up and improve comments in test-code, and add
MODULE_DESCRIPTIONs.

Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
---
v5b - parens-on-PARAM
---
 drivers/gpu/drm/drm_print.c     |  8 ++---
 include/drm/drm_print.h         |  6 ++--
 include/linux/dynamic_debug.h   | 37 ++++++++++++++++++++-
 lib/test_dynamic_debug.c        | 58 +++++++++++++--------------------
 lib/test_dynamic_debug_submod.c |  9 ++++-
 5 files changed, 73 insertions(+), 45 deletions(-)

diff --git a/drivers/gpu/drm/drm_print.c b/drivers/gpu/drm/drm_print.c
index dabcfa0dd279..8f4b609353a5 100644
--- a/drivers/gpu/drm/drm_print.c
+++ b/drivers/gpu/drm/drm_print.c
@@ -69,12 +69,8 @@ DRM_CLASSMAP_DEFINE(drm_debug_classes, DD_CLASS_TYPE_DISJOINT_BITS,
 		    "DRM_UT_DP",
 		    "DRM_UT_DRMRES");
 
-static struct ddebug_class_param drm_debug_bitmap = {
-	.bits = &__drm_debug,
-	.flags = "p",
-	.map = &drm_debug_classes,
-};
-module_param_cb(debug, &param_ops_dyndbg_classes, &drm_debug_bitmap, 0600);
+DRM_CLASSMAP_PARAM_REF(debug, __drm_debug, drm_debug_classes, p);
+
 #endif
 
 void __drm_puts_coredump(struct drm_printer *p, const char *str)
diff --git a/include/drm/drm_print.h b/include/drm/drm_print.h
index 706afc97c79c..94d4f5500030 100644
--- a/include/drm/drm_print.h
+++ b/include/drm/drm_print.h
@@ -322,11 +322,13 @@ enum drm_debug_category {
 };
 
 #ifdef CONFIG_DRM_USE_DYNAMIC_DEBUG
-#define DRM_CLASSMAP_DEFINE(...) DYNDBG_CLASSMAP_DEFINE(__VA_ARGS__)
-#define DRM_CLASSMAP_USE(name)   DYNDBG_CLASSMAP_USE(name)
+#define DRM_CLASSMAP_DEFINE(...)	DYNDBG_CLASSMAP_DEFINE(__VA_ARGS__)
+#define DRM_CLASSMAP_USE(name)		DYNDBG_CLASSMAP_USE(name)
+#define DRM_CLASSMAP_PARAM_REF(...)	DYNDBG_CLASSMAP_PARAM_REF(__VA_ARGS__)
 #else
 #define DRM_CLASSMAP_DEFINE(...)
 #define DRM_CLASSMAP_USE(name)
+#define DRM_CLASSMAP_PARAM_REF(...)
 #endif
 
 static inline bool drm_debug_enabled_raw(enum drm_debug_category category)
diff --git a/include/linux/dynamic_debug.h b/include/linux/dynamic_debug.h
index 1b027be2cdc4..f182f95caabb 100644
--- a/include/linux/dynamic_debug.h
+++ b/include/linux/dynamic_debug.h
@@ -91,7 +91,7 @@ struct ddebug_class_map {
  * used to validate a "class FOO .." >control command on the module
  */
 #define DYNDBG_CLASSMAP_DEFINE(_var, _maptype, _base, ...)		\
-	const char *_var##_classnames[] = { __VA_ARGS__ };		\
+	static const char *_var##_classnames[] = { __VA_ARGS__ };	\
 	struct ddebug_class_map __aligned(8) __used			\
 		__section("__dyndbg_classes") _var = {			\
 		.mod = THIS_MODULE,					\
@@ -145,6 +145,41 @@ struct ddebug_class_param {
 	const struct ddebug_class_map *map;
 };
 
+/**
+ * DYNDBG_CLASSMAP_PARAM - wrap a dyndbg-classmap with a controlling sys-param
+ * @_name  sysfs node name
+ * @_var   name of the struct classmap var defining the controlled classes
+ * @_flags flags to be toggled, typically just 'p'
+ *
+ * Creates a sysfs-param to control the classes defined by the
+ * classmap.  Keeps bits in a private/static
+ */
+#define DYNDBG_CLASSMAP_PARAM(_name, _var, _flags)			\
+	static unsigned long _name##_bvec;				\
+	__DYNDBG_CLASSMAP_PARAM(_name, _name##_bvec, _var, _flags)
+
+/**
+ * DYNDBG_CLASSMAP_PARAM_REF - wrap a dyndbg-classmap with a controlling sys-param
+ * @_name  sysfs node name
+ * @_bits  name of the module's unsigned long bit-vector, ex: __drm_debug
+ * @_var   name of the struct classmap var defining the controlled classes
+ * @_flags flags to be toggled, typically just 'p'
+ *
+ * Creates a sysfs-param to control the classmap, keeping bitvec in user @_bits.
+ * This lets drm use __drm_debug elsewhere too.
+ */
+#define DYNDBG_CLASSMAP_PARAM_REF(_name, _bits, _var, _flags)		\
+	__DYNDBG_CLASSMAP_PARAM(_name, _bits, _var, _flags)
+
+#define __DYNDBG_CLASSMAP_PARAM(_name, _bits, _var, _flags)		\
+	static struct ddebug_class_param _name##_##_flags = {		\
+		.bits = &(_bits),					\
+		.flags = #_flags,					\
+		.map = &(_var),						\
+	};								\
+	module_param_cb(_name, &param_ops_dyndbg_classes,		\
+			&_name##_##_flags, 0600)
+
 /*
  * pr_debug() and friends are globally enabled or modules have selectively
  * enabled them.
diff --git a/lib/test_dynamic_debug.c b/lib/test_dynamic_debug.c
index 23967071b60f..84e049c07e77 100644
--- a/lib/test_dynamic_debug.c
+++ b/lib/test_dynamic_debug.c
@@ -1,6 +1,7 @@
 // SPDX-License-Identifier: GPL-2.0-only
 /*
- * Kernel module for testing dynamic_debug
+ * Kernel module to test/demonstrate dynamic_debug features,
+ * particularly classmaps and their support for subsystems like DRM.
  *
  * Authors:
  *      Jim Cromie	<jim.cromie@gmail.com>
@@ -35,24 +36,8 @@ module_param_cb(do_prints, &param_ops_do_prints, NULL, 0600);
 
 #define CLASSMAP_BITMASK(width, base) (((1UL << (width)) - 1) << base)
 
-/* sysfs param wrapper, proto-API */
-#define DYNDBG_CLASSMAP_PARAM_(_model, _flags, _init)			\
-	static unsigned long bits_##_model = _init;			\
-	static struct ddebug_class_param _flags##_##_model = {		\
-		.bits = &bits_##_model,					\
-		.flags = #_flags,					\
-		.map = &map_##_model,					\
-	};								\
-	module_param_cb(_flags##_##_model, &param_ops_dyndbg_classes,	\
-			&_flags##_##_model, 0600)
-#ifdef DEBUG
-#define DYNDBG_CLASSMAP_PARAM(_model, _flags)  DYNDBG_CLASSMAP_PARAM_(_model, _flags, ~0)
-#else
-#define DYNDBG_CLASSMAP_PARAM(_model, _flags)  DYNDBG_CLASSMAP_PARAM_(_model, _flags, 0)
-#endif
-
 /*
- * Demonstrate/test all 4 class-typed classmaps with a sys-param.
+ * Demonstrate/test both types of classmaps, each with a sys-param.
  *
  * Each is 3 part: client-enum decl, _DEFINE, _PARAM.
  * Declare them in blocks to show patterns of use (repetitions and
@@ -64,7 +49,7 @@ module_param_cb(do_prints, &param_ops_do_prints, NULL, 0600);
  * Modules with multiple CLASSMAPS must have enums with distinct
  * value-ranges, arranged below with explicit enum_sym = X inits.
  *
- * Declare all 4 enums now, for different types
+ * Declare all enums now, for different types
  */
 
 /* numeric input, independent bits */
@@ -83,18 +68,21 @@ enum cat_disjoint_bits {
 /* numeric verbosity, V2 > V1 related */
 enum cat_level_num { V0 = 14, V1, V2, V3, V4, V5, V6, V7 };
 
-/* named-symbolic input, independent bits */
+/*
+  and possibly later, params accepting named-value inputs
+*/
 enum cat_disjoint_names { LOW = 10, MID, HI };
+enum cat_level_names    { L0 = 22, L1, L2, L3, L4, L5, L6, L7 };
 
-/* named-symbolic verbosity */
-enum cat_level_names { L0 = 22, L1, L2, L3, L4, L5, L6, L7 };
-
-/* recapitulate DRM's parent(drm.ko) <-- _submod(drivers,helpers) */
+/*
+ * use/demonstrate multi-module-group classmaps, as for DRM
+ */
 #if !defined(TEST_DYNAMIC_DEBUG_SUBMOD)
 /*
- * In single user, or parent / coordinator (drm.ko) modules, define
- * classmaps on the client enums above, and then declares the PARAMS
- * ref'g the classmaps.  Each is exported.
+ * For module-groups of 1+, define classmaps with names (stringified
+ * enum-symbols) copied from above. 1-to-1 mapping is recommended.
+ * The classmap is exported, so that other modules in the group can
+ * link to it and control their prdbgs.
  */
 DYNDBG_CLASSMAP_DEFINE(map_disjoint_bits, DD_CLASS_TYPE_DISJOINT_BITS,
 		       D2_CORE,
@@ -113,19 +101,18 @@ DYNDBG_CLASSMAP_DEFINE(map_level_num, DD_CLASS_TYPE_LEVEL_NUM,
 		       V0, "V0", "V1", "V2", "V3", "V4", "V5", "V6", "V7");
 
 /*
- * now add the sysfs-params
+ * for use-cases that want it, provide a sysfs-param to set the
+ * classes in the classmap.  It is at this interface where the
+ * "v3>v2" property is applied to DD_CLASS_TYPE_LEVEL_NUM inputs.
  */
-
-DYNDBG_CLASSMAP_PARAM(disjoint_bits, p);
-DYNDBG_CLASSMAP_PARAM(level_num, p);
+DYNDBG_CLASSMAP_PARAM(p_disjoint_bits,	map_disjoint_bits, p);
+DYNDBG_CLASSMAP_PARAM(p_level_num,	map_level_num, p);
 
 #else /* TEST_DYNAMIC_DEBUG_SUBMOD */
-
 /*
- * in submod/drm-drivers, use the classmaps defined in top/parent
- * module above.
+ * the +1 members of a multi-module group refer to the classmap
+ * DEFINEd (and exported) above.
  */
-
 DYNDBG_CLASSMAP_USE(map_disjoint_bits);
 DYNDBG_CLASSMAP_USE(map_level_num);
 
@@ -186,5 +173,6 @@ static void __exit test_dynamic_debug_exit(void)
 module_init(test_dynamic_debug_init);
 module_exit(test_dynamic_debug_exit);
 
+MODULE_DESCRIPTION("test/demonstrate dynamic-debug features");
 MODULE_AUTHOR("Jim Cromie <jim.cromie@gmail.com>");
 MODULE_LICENSE("GPL");
diff --git a/lib/test_dynamic_debug_submod.c b/lib/test_dynamic_debug_submod.c
index 9a893402ce1a..0d15f3ffe466 100644
--- a/lib/test_dynamic_debug_submod.c
+++ b/lib/test_dynamic_debug_submod.c
@@ -1,6 +1,9 @@
 // SPDX-License-Identifier: GPL-2.0
 /*
- * Kernel module for testing dynamic_debug
+ * Kernel module to test/demonstrate dynamic_debug features,
+ * particularly classmaps and their support for subsystems, like DRM,
+ * which defines its drm_debug classmap in drm module, and uses it in
+ * helpers & drivers.
  *
  * Authors:
  *      Jim Cromie	<jim.cromie@gmail.com>
@@ -8,3 +11,7 @@
 
 #define TEST_DYNAMIC_DEBUG_SUBMOD
 #include "test_dynamic_debug.c"
+
+MODULE_DESCRIPTION("test/demonstrate dynamic-debug subsystem support");
+MODULE_AUTHOR("Jim Cromie <jim.cromie@gmail.com>");
+MODULE_LICENSE("GPL");
-- 
2.41.0

[PATCH v7 18/25] dyndbg-doc: add classmap info to howto

[Jim Cromie]

Add some basic info on classmap usage and api

Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
---
v5- adjustments per Randy Dunlap, me
---
 .../admin-guide/dynamic-debug-howto.rst       | 59 ++++++++++++++++++-
 1 file changed, 58 insertions(+), 1 deletion(-)

diff --git a/Documentation/admin-guide/dynamic-debug-howto.rst b/Documentation/admin-guide/dynamic-debug-howto.rst
index 0b3d39c610d9..d8813dcc394a 100644
--- a/Documentation/admin-guide/dynamic-debug-howto.rst
+++ b/Documentation/admin-guide/dynamic-debug-howto.rst
@@ -225,7 +225,6 @@ the ``p`` flag has meaning, other flags are ignored.
 Note the regexp ``^[-+=][fslmpt_]+$`` matches a flags specification.
 To clear all flags at once, use ``=_`` or ``-fslmpt``.
 
-
 Debug messages during Boot Process
 ==================================
 
@@ -375,3 +374,61 @@ just a shortcut for ``print_hex_dump(KERN_DEBUG)``.
 For ``print_hex_dump_debug()``/``print_hex_dump_bytes()``, format string is
 its ``prefix_str`` argument, if it is constant string; or ``hexdump``
 in case ``prefix_str`` is built dynamically.
+
+Dynamic Debug classmaps
+=======================
+
+Dyndbg allows selection/grouping of *prdbg* callsites using structural
+info: module, file, function, line.  Classmaps allow authors to add
+their own domain-oriented groupings using class-names.  Classmaps are
+exported, so they referencable from other modules.
+
+  # enable classes individually
+  :#> ddcmd class DRM_UT_CORE +p
+  :#> ddcmd class DRM_UT_KMS +p
+  # or more selectively
+  :#> ddcmd class DRM_UT_CORE module drm +p
+
+The "class FOO" syntax protects class'd prdbgs from generic overwrite::
+
+  # IOW this doesn't wipe any DRM.debug settings
+  :#> ddcmd -p
+
+To support the DRM.debug parameter, DYNDBG_CLASSMAP_PARAM* updates all
+classes in a classmap, mapping param-bits 0..N onto the classes:
+DRM_UT_<*> for the DRM use-case.
+
+Dynamic Debug Classmap API
+==========================
+
+DYNDBG_CLASSMAP_DEFINE - modules use this to create classmaps, naming
+each of the classes (stringified enum-symbols: "DRM_UT_<*>"), and
+type, and mapping the class-names to consecutive _class_ids.
+
+By doing so, modules tell dyndbg that they are have prdbgs with those
+class_ids, and they authorize dyndbg to accept "class FOO" for module
+defining that classname.
+
+There are 2 types of classmaps:
+
+ DD_CLASS_TYPE_DISJOINT_BITS: classes are independent, like DRM.debug
+ DD_CLASS_TYPE_LEVEL_NUM: classes are relative, ordered (V3 > V2)
+
+DYNDBG_CLASSMAP_PARAM - refers to a DEFINEd classmap, exposing the set
+of defined classes to manipulation as a group.  This interface
+enforces the relatedness of classes of DD_CLASS_TYPE_LEVEL_NUM typed
+classmaps; all classes are independent in the >control parser itself.
+
+DYNDBG_CLASSMAP_USE - drm drivers invoke this to ref the the CLASSMAP
+that drm DEFINEs.  This shares the classmap definition, and authorizes
+dyndbg to apply changes to the using modules class'd pr_debugs.  It
+also tells dyndbg how to initialize the user's prdbgs at modprobe.
+
+Modules or module-groups (drm & drivers) can define multiple
+classmaps, as long as they share the limited 0..62 per-module-group
+_class_id range, without overlap.
+
+``#define DEBUG`` will enable all pr_debugs in scope, including any
+class'd ones.  This won't be reflected in the PARAM readback value,
+but the pr_debug callsites can be toggled into agreement with the
+param.
-- 
2.41.0

[PATCH v7 19/25] dyndbg: reserve flag bit _DPRINTK_FLAGS_PREFIX_CACHED

[Jim Cromie]

Reserve bit 7 to remember that a pr-debug callsite is/was:
- enabled, with +p
- wants a dynamic-prefix, with one+ of module:function:sourcfile
- was previously called
- was thus saved in the cache. NOT YET.

Its unclear whether any cache fetch would be faster than 2-3 field
fetches, but theres another factor; the 3 columns in the __dyndbg
section are highly redundant and compressible, but to get the
compression, we need field accessors, which will rebalance the
tradeoff.

So, for now, its just the bit reservation.

Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
---
 include/linux/dynamic_debug.h | 1 +
 1 file changed, 1 insertion(+)

diff --git a/include/linux/dynamic_debug.h b/include/linux/dynamic_debug.h
index f182f95caabb..927cb14f24e0 100644
--- a/include/linux/dynamic_debug.h
+++ b/include/linux/dynamic_debug.h
@@ -38,6 +38,7 @@ struct _ddebug {
 #define _DPRINTK_FLAGS_INCL_LINENO	(1<<3)
 #define _DPRINTK_FLAGS_INCL_TID		(1<<4)
 #define _DPRINTK_FLAGS_INCL_SOURCENAME	(1<<5)
+#define _DPRINTK_FLAGS_PREFIX_CACHED	(1<<7)
 
 #define _DPRINTK_FLAGS_INCL_ANY		\
 	(_DPRINTK_FLAGS_INCL_MODNAME | _DPRINTK_FLAGS_INCL_FUNCNAME |\
-- 
2.41.0

[PATCH v7 20/25] dyndbg: add _DPRINTK_FLAGS_INCL_LOOKUP

[Jim Cromie]

dyndbg's dynamic prefixing (by +tmfsl flags) is needlessly expensive.

When an enabled (with +p) pr_debug is called, _DPRINTK_FLAGS_INCL_ANY
prefix decorations are sprintf'd into stack-mem for every call.

This string (or part of it) could be cached once its 1st generated,
and retreived thereafter, as long as its deleted any time the
callsite's flags are changed afterwards.

So consider the prefix/decoration flags: 'tmfsl', and what should be
in the cache:

-t  thread-id. not part of the "callsite" info, derived from current.
    doesnt belong in the cache. it would be wrong.
    can be done in outer: dynamic_emit_prefix()

-l  line number
    this could be part of the prefix, but would bloat the cache
    can also be done in outer: dynamic_emit_prefix()

-mfs  module, function, source-file
    we cache these, composed into a sub-string.
    they are "lookups", currently to descriptor fields,
    could be accessor macros to "compressed" tables.
    cache saves more access work.

All enabled together, they compose a prefix string like:

  # outer   -----inner----------   outer
  "[tid] module:function:sourcfile:line: "

So this patch extracts _DPRINTK_FLAGS_INCL_LOOKUP macro out of
_DPRINTK_FLAGS_INCL_ANY macro, then redefs latter.

Next re-refactor dynamic_emit_prefix inner/outer fns accordingly.

Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
---
 include/linux/dynamic_debug.h | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/include/linux/dynamic_debug.h b/include/linux/dynamic_debug.h
index 927cb14f24e0..2237d454bc19 100644
--- a/include/linux/dynamic_debug.h
+++ b/include/linux/dynamic_debug.h
@@ -40,10 +40,12 @@ struct _ddebug {
 #define _DPRINTK_FLAGS_INCL_SOURCENAME	(1<<5)
 #define _DPRINTK_FLAGS_PREFIX_CACHED	(1<<7)
 
-#define _DPRINTK_FLAGS_INCL_ANY		\
-	(_DPRINTK_FLAGS_INCL_MODNAME | _DPRINTK_FLAGS_INCL_FUNCNAME |\
-	 _DPRINTK_FLAGS_INCL_LINENO  | _DPRINTK_FLAGS_INCL_TID |\
+#define _DPRINTK_FLAGS_INCL_LOOKUP					\
+	(_DPRINTK_FLAGS_INCL_MODNAME | _DPRINTK_FLAGS_INCL_FUNCNAME |	\
 	 _DPRINTK_FLAGS_INCL_SOURCENAME)
+#define _DPRINTK_FLAGS_INCL_ANY						\
+	(_DPRINTK_FLAGS_INCL_LINENO | _DPRINTK_FLAGS_INCL_TID |		\
+	 _DPRINTK_FLAGS_INCL_LOOKUP)
 
 #if defined DEBUG
 #define _DPRINTK_FLAGS_DEFAULT _DPRINTK_FLAGS_PRINT
-- 
2.41.0

[PATCH v7 21/25] dyndbg: refactor *dynamic_emit_prefix

[Jim Cromie]

Refactor the split of duties between outer & inner fns.

The outer fn was previously just an inline unlikely forward to inner,
which did all the work.

Now, outer handles +t and +l flags itself, and calls inner only when
_DPRINTK_FLAGS_INCL_LOOKUP is needed.

No functional change.

But it does make the results of the inner-fn more cache-friendly
(fewer entries, reused more often):

1- no spurious [TID] or <intr> noise
2- no LINE-number to bloat the cache (avg 9 pr_debugs/fn)
3- only LOOKUP stuff

Currently LOOKUPs are descriptor-field refs but could be replaced by
accessor functions.  This would allow the __dyndbg_sites section to be
de-duplicated and reclaimed; currently module, filename fields are
~90% repeated.  As the accessors get more expensive, the value of
caching part of the prefix goes up.

Also change inner-fn to return count of extra chars written to the
buffer, and drop "inline" from outer, let the compiler decide.  Maybe
also change name accordingly.

Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
---
 lib/dynamic_debug.c | 55 ++++++++++++++++++++++++---------------------
 1 file changed, 30 insertions(+), 25 deletions(-)

diff --git a/lib/dynamic_debug.c b/lib/dynamic_debug.c
index 17eefb35ac96..974395bf8a83 100644
--- a/lib/dynamic_debug.c
+++ b/lib/dynamic_debug.c
@@ -777,19 +777,8 @@ static int remaining(int wrote)
 	return 0;
 }
 
-static char *__dynamic_emit_prefix(const struct _ddebug *desc, char *buf)
+static int __dynamic_emit_prefix(const struct _ddebug *desc, char *buf, int pos)
 {
-	int pos_after_tid;
-	int pos = 0;
-
-	if (desc->flags & _DPRINTK_FLAGS_INCL_TID) {
-		if (in_interrupt())
-			pos += snprintf(buf + pos, remaining(pos), "<intr> ");
-		else
-			pos += snprintf(buf + pos, remaining(pos), "[%d] ",
-					task_pid_vnr(current));
-	}
-	pos_after_tid = pos;
 	if (desc->flags & _DPRINTK_FLAGS_INCL_MODNAME)
 		pos += snprintf(buf + pos, remaining(pos), "%s:",
 				desc->modname);
@@ -799,22 +788,38 @@ static char *__dynamic_emit_prefix(const struct _ddebug *desc, char *buf)
 	if (desc->flags & _DPRINTK_FLAGS_INCL_SOURCENAME)
 		pos += snprintf(buf + pos, remaining(pos), "%s:",
 				trim_prefix(desc->filename));
-	if (desc->flags & _DPRINTK_FLAGS_INCL_LINENO)
-		pos += snprintf(buf + pos, remaining(pos), "%d:",
-				desc->lineno);
-	if (pos - pos_after_tid)
-		pos += snprintf(buf + pos, remaining(pos), " ");
-	if (pos >= PREFIX_SIZE)
-		buf[PREFIX_SIZE - 1] = '\0';
-
-	return buf;
+	return pos;
 }
 
-static inline char *dynamic_emit_prefix(struct _ddebug *desc, char *buf)
+static char *dynamic_emit_prefix(struct _ddebug *desc, char *buf)
 {
-	if (unlikely(desc->flags & _DPRINTK_FLAGS_INCL_ANY))
-		return __dynamic_emit_prefix(desc, buf);
-	return buf;
+        int pos_after_tid;
+        int pos = 0;
+
+        if (likely(!(desc->flags & _DPRINTK_FLAGS_INCL_ANY)))
+                return buf;
+
+        if (desc->flags & _DPRINTK_FLAGS_INCL_TID) {
+                if (in_interrupt())
+                        pos += snprintf(buf + pos, remaining(pos), "<intr> ");
+                else
+                        pos += snprintf(buf + pos, remaining(pos), "[%d] ",
+                                        task_pid_vnr(current));
+        }
+        pos_after_tid = pos;
+
+        if (unlikely(desc->flags & _DPRINTK_FLAGS_INCL_LOOKUP))
+                pos += __dynamic_emit_prefix(desc, buf, pos);
+
+        if (desc->flags & _DPRINTK_FLAGS_INCL_LINENO)
+                pos += snprintf(buf + pos, remaining(pos), "%d:",
+                                desc->lineno);
+        if (pos - pos_after_tid)
+                pos += snprintf(buf + pos, remaining(pos), " ");
+        if (pos >= PREFIX_SIZE)
+                buf[PREFIX_SIZE - 1] = '\0';
+
+        return buf;
 }
 
 void __dynamic_pr_debug(struct _ddebug *descriptor, const char *fmt, ...)
-- 
2.41.0

[PATCH v7 22/25] dyndbg: improve err report in attach_user_module_classes

[Jim Cromie]

convert a WARN on 3 conditions, into BUG_ON 2 of them (which don't
happen), and an early return on (!cli->user_mod_name), which *was*
happening, so should be seen going forward.  Maybe this should be a
WARN.

NB: The underlying problem was a missing __align(8) in the
DYNDBG_CLASSMAP_USE, which manifested as a corrupt record with a map
pointer which segv'd.

Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
---
 lib/dynamic_debug.c | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/lib/dynamic_debug.c b/lib/dynamic_debug.c
index 974395bf8a83..3dc512fb1d66 100644
--- a/lib/dynamic_debug.c
+++ b/lib/dynamic_debug.c
@@ -1284,9 +1284,11 @@ static void ddebug_attach_user_module_classes(struct ddebug_table *dt,
 	 */
 	for_each_boxed_vector(di, class_users, num_class_users, i, cli) {
 
-		if (WARN_ON(!cli || !cli->map || !cli->user_mod_name))
-			continue;
-
+		BUG_ON(!cli || !cli->map);
+		if (!cli->user_mod_name) {
+			pr_warn("class_ref[%d] !user-mod-name looking for %s\n", i, dt->mod_name);
+			return;
+		}
 		if (!strcmp(cli->user_mod_name, dt->mod_name)) {
 
 			vpr_cm_info(cli->map, "class_ref[%d] %s -> %s", i,
-- 
2.41.0

[PATCH v7 23/25] drm: use correct ccflags-y spelling

[Jim Cromie]

Incorrectly spelled CFLAGS- failed to add -DDYNAMIC_DEBUG_MODULE,
which broke builds with:

CONFIG_DRM_USE_DYNAMIC_DEBUG=y
CONFIG_DYNAMIC_DEBUG_CORE=y
CONFIG_DYNAMIC_DEBUG=n

Also add subdir-ccflags so that all drivers pick up the addition.

Fixes: 84ec67288c10 ("drm_print: wrap drm_*_dbg in dyndbg descriptor factory macro")
Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
---
 drivers/gpu/drm/Makefile | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/Makefile b/drivers/gpu/drm/Makefile
index 215e78e79125..22b1984cc982 100644
--- a/drivers/gpu/drm/Makefile
+++ b/drivers/gpu/drm/Makefile
@@ -3,7 +3,8 @@
 # Makefile for the drm device driver.  This driver provides support for the
 # Direct Rendering Infrastructure (DRI) in XFree86 4.1.0 and higher.
 
-CFLAGS-$(CONFIG_DRM_USE_DYNAMIC_DEBUG)	+= -DDYNAMIC_DEBUG_MODULE
+ccflags-$(CONFIG_DRM_USE_DYNAMIC_DEBUG)		+= -DDYNAMIC_DEBUG_MODULE
+subdir-ccflags-$(CONFIG_DRM_USE_DYNAMIC_DEBUG)	+= -DDYNAMIC_DEBUG_MODULE
 
 drm-y := \
 	drm_aperture.o \
-- 
2.41.0

[PATCH v7 24/25] drm-drivers: DRM_CLASSMAP_USE in 2nd batch of drivers, helpers

[Jim Cromie]

Add a DRM_CLASSMAP_USE declaration to 2nd batch of helpers and *_drv.c
files.  For drivers, add the decl just above the module's PARAMs,
since it identifies the "inherited" drm.debug param.

Note: with CONFIG_DRM_USE_DYNAMIC_DEBUG=y, a module not also declaring
DRM_CLASSMAP_USE will have its class'd prdbgs stuck in the initial
(disabled, but for DEBUG) state.

The stuck sites are evident in /proc/dynamic_debug/control as:

   class:_UNKNOWN_ _id:N		# control's last column

rather than a proper "enumeration":

   class:DRM_UT_CORE

This set of updates was found by choosing M for all DRM-config items I
found (not allmodconfig), building & modprobing them, and grepping
"class unknown," control.  There may yet be others.

Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
---
 drivers/gpu/drm/drm_gem_shmem_helper.c | 2 ++
 drivers/gpu/drm/gud/gud_drv.c          | 2 ++
 drivers/gpu/drm/mgag200/mgag200_drv.c  | 2 ++
 drivers/gpu/drm/qxl/qxl_drv.c          | 2 ++
 drivers/gpu/drm/radeon/radeon_drv.c    | 2 ++
 drivers/gpu/drm/udl/udl_main.c         | 2 ++
 drivers/gpu/drm/vkms/vkms_drv.c        | 2 ++
 drivers/gpu/drm/vmwgfx/vmwgfx_drv.c    | 2 ++
 8 files changed, 16 insertions(+)

diff --git a/drivers/gpu/drm/drm_gem_shmem_helper.c b/drivers/gpu/drm/drm_gem_shmem_helper.c
index e435f986cd13..066d906e3199 100644
--- a/drivers/gpu/drm/drm_gem_shmem_helper.c
+++ b/drivers/gpu/drm/drm_gem_shmem_helper.c
@@ -23,6 +23,8 @@
 #include <drm/drm_prime.h>
 #include <drm/drm_print.h>
 
+DRM_CLASSMAP_USE(drm_debug_classes);
+
 MODULE_IMPORT_NS(DMA_BUF);
 
 /**
diff --git a/drivers/gpu/drm/gud/gud_drv.c b/drivers/gpu/drm/gud/gud_drv.c
index 9d7bf8ee45f1..5b555045fce4 100644
--- a/drivers/gpu/drm/gud/gud_drv.c
+++ b/drivers/gpu/drm/gud/gud_drv.c
@@ -31,6 +31,8 @@
 
 #include "gud_internal.h"
 
+DRM_CLASSMAP_USE(drm_debug_classes);
+
 /* Only used internally */
 static const struct drm_format_info gud_drm_format_r1 = {
 	.format = GUD_DRM_FORMAT_R1,
diff --git a/drivers/gpu/drm/mgag200/mgag200_drv.c b/drivers/gpu/drm/mgag200/mgag200_drv.c
index abddf37f0ea1..d678eb8e028d 100644
--- a/drivers/gpu/drm/mgag200/mgag200_drv.c
+++ b/drivers/gpu/drm/mgag200/mgag200_drv.c
@@ -24,6 +24,8 @@ static int mgag200_modeset = -1;
 MODULE_PARM_DESC(modeset, "Disable/Enable modesetting");
 module_param_named(modeset, mgag200_modeset, int, 0400);
 
+DRM_CLASSMAP_USE(drm_debug_classes);
+
 int mgag200_init_pci_options(struct pci_dev *pdev, u32 option, u32 option2)
 {
 	struct device *dev = &pdev->dev;
diff --git a/drivers/gpu/drm/qxl/qxl_drv.c b/drivers/gpu/drm/qxl/qxl_drv.c
index b30ede1cf62d..91942ffcc2b4 100644
--- a/drivers/gpu/drm/qxl/qxl_drv.c
+++ b/drivers/gpu/drm/qxl/qxl_drv.c
@@ -65,6 +65,8 @@ module_param_named(modeset, qxl_modeset, int, 0400);
 MODULE_PARM_DESC(num_heads, "Number of virtual crtcs to expose (default 4)");
 module_param_named(num_heads, qxl_num_crtc, int, 0400);
 
+DRM_CLASSMAP_USE(drm_debug_classes);
+
 static struct drm_driver qxl_driver;
 static struct pci_driver qxl_pci_driver;
 
diff --git a/drivers/gpu/drm/radeon/radeon_drv.c b/drivers/gpu/drm/radeon/radeon_drv.c
index fa531493b111..ab29945af657 100644
--- a/drivers/gpu/drm/radeon/radeon_drv.c
+++ b/drivers/gpu/drm/radeon/radeon_drv.c
@@ -247,6 +247,8 @@ int radeon_cik_support = 1;
 MODULE_PARM_DESC(cik_support, "CIK support (1 = enabled (default), 0 = disabled)");
 module_param_named(cik_support, radeon_cik_support, int, 0444);
 
+DRM_CLASSMAP_USE(drm_debug_classes);
+
 static struct pci_device_id pciidlist[] = {
 	radeon_PCI_IDS
 };
diff --git a/drivers/gpu/drm/udl/udl_main.c b/drivers/gpu/drm/udl/udl_main.c
index 3ebe2ce55dfd..ba57c14454e5 100644
--- a/drivers/gpu/drm/udl/udl_main.c
+++ b/drivers/gpu/drm/udl/udl_main.c
@@ -19,6 +19,8 @@
 
 #define NR_USB_REQUEST_CHANNEL 0x12
 
+DRM_CLASSMAP_USE(drm_debug_classes);
+
 #define MAX_TRANSFER (PAGE_SIZE*16 - BULK_SIZE)
 #define WRITES_IN_FLIGHT (20)
 #define MAX_VENDOR_DESCRIPTOR_SIZE 256
diff --git a/drivers/gpu/drm/vkms/vkms_drv.c b/drivers/gpu/drm/vkms/vkms_drv.c
index dd0af086e7fa..086797c4b82b 100644
--- a/drivers/gpu/drm/vkms/vkms_drv.c
+++ b/drivers/gpu/drm/vkms/vkms_drv.c
@@ -39,6 +39,8 @@
 
 static struct vkms_config *default_config;
 
+DRM_CLASSMAP_USE(drm_debug_classes);
+
 static bool enable_cursor = true;
 module_param_named(enable_cursor, enable_cursor, bool, 0444);
 MODULE_PARM_DESC(enable_cursor, "Enable/Disable cursor support");
diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_drv.c b/drivers/gpu/drm/vmwgfx/vmwgfx_drv.c
index 8b24ecf60e3e..9cb6be422621 100644
--- a/drivers/gpu/drm/vmwgfx/vmwgfx_drv.c
+++ b/drivers/gpu/drm/vmwgfx/vmwgfx_drv.c
@@ -275,6 +275,8 @@ static int vmw_probe(struct pci_dev *, const struct pci_device_id *);
 static int vmwgfx_pm_notifier(struct notifier_block *nb, unsigned long val,
 			      void *ptr);
 
+DRM_CLASSMAP_USE(drm_debug_classes);
+
 MODULE_PARM_DESC(restrict_iommu, "Try to limit IOMMU usage for TTM pages");
 module_param_named(restrict_iommu, vmw_restrict_iommu, int, 0600);
 MODULE_PARM_DESC(force_coherent, "Force coherent TTM pages");
-- 
2.41.0

[PATCH v7 25/25] drm: restore CONFIG_DRM_USE_DYNAMIC_DEBUG un-BROKEN

[Jim Cromie]

Lots of burn-in testing needed before signing, upstreaming.

NOTE: I set default Y to maximize testing by default.
Is there a better way to do this ?

Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
---
 drivers/gpu/drm/Kconfig | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/Kconfig b/drivers/gpu/drm/Kconfig
index 3caa020391c7..708f5e8cb205 100644
--- a/drivers/gpu/drm/Kconfig
+++ b/drivers/gpu/drm/Kconfig
@@ -55,8 +55,7 @@ config DRM_DEBUG_MM
 
 config DRM_USE_DYNAMIC_DEBUG
 	bool "use dynamic debug to implement drm.debug"
-	default n
-	depends on BROKEN
+	default y
 	depends on DRM
 	depends on DYNAMIC_DEBUG || DYNAMIC_DEBUG_CORE
 	depends on JUMP_LABEL
-- 
2.41.0

[PATCH v7 00/25] fix DRM_USE_DYNAMIC_DEBUG=y regression

[Jim Cromie]

hi Jason, DRM-folk

This patchest fixes the chicken-egg initialization problem in the 1st
version of ddebug-class-maps, that DRM-CI uncovered.

The root-problem was DECLARE_DYNDBG_CLASSMAP, which broke the K&R rule:
"define once, refer many".  In patch 14 it is replaced by:

 DYNDBG_CLASSMAP_DEFINE - define and export a struct ddebug_class_map
 DYNDBG_CLASSMAP_USE - ref the exported struct

test-dynamic-debug is also extended with a -submod.ko, in order to
recapitulate the drm & drivers initialization scenario.

They're on v6.6-rc5 now, and apply cleanly to drm-tip/drm-tip.

Ive been running recent revs on rc3+, on my desktop and laptop.

The final blocker was a missing __align(8) on the ddebug_class_user
record inserted by DYNDBG_CLASSMAP_USE.  This caused DRM=y (builtin
only) to have a corrupt record for drm_kms_helper (builtin dependent).
Curiously, a clang build did not exhibit this problem.

Heres a part of dmesg, for a DRM=y kernel, booted with
     dynamic_debug.verbose=3 drm.debug=0x10

[    0.466747] dyndbg: add-module: drm 406 sites
[    0.467569] dyndbg: classes[0]: module:drm base:0 len:10 type:DISJOINT_BITS
[    0.467743] dyndbg: module:drm attached 1 classes
[    0.468557] dyndbg: builtin class: module:drm base:0 len:10 type:DISJOINT_BITS
[    0.468742] dyndbg:  found kp:drm.debug =0x10
[    0.468743] dyndbg:   mapped to: module:drm base:0 len:10 type:DISJOINT_BITS
[    0.469742] dyndbg:   drm.debug: classbits: 0x10
[    0.470573] dyndbg: apply bitmap: 0x10 to: 0x0 for drm
[    0.470743] dyndbg: query 0: "class DRM_UT_ATOMIC +p" mod:drm
[    0.471743] dyndbg: split into words: "class" "DRM_UT_ATOMIC" "+p"
[    0.472743] dyndbg: op='+' flags=0x1 maskp=0xffffffff
[    0.473679] dyndbg: parsed: func="" file="" module="drm" format="" lineno=0-0 class=DRM_UT_ATOMIC
[    0.473749] dyndbg: processed 1 queries, with 0 matches, 0 errs
[    0.474742] dyndbg: bit_4: 0 matches on class: DRM_UT_ATOMIC -> 0x10
[    0.475742] dyndbg: applied bitmap: 0x10 to: 0x0 for drm
[    0.476686] dyndbg: 406 debug prints in module drm
[    0.476743] dyndbg: add-module: drm_kms_helper 93 sites
[    0.477727] dyndbg: class_ref[0] drm_kms_helper -> drm module:drm base:0 len:10 type:DISJOINT_BITS
[    0.477743] dyndbg: builtin class: module:drm base:0 len:10 type:DISJOINT_BITS
[    0.478742] dyndbg:  found kp:drm.debug =0x10
[    0.478743] dyndbg:   mapped to: module:drm base:0 len:10 type:DISJOINT_BITS
[    0.479743] dyndbg:   drm.debug: classbits: 0x10
[    0.480592] dyndbg: apply bitmap: 0x10 to: 0x0 for drm_kms_helper
[    0.480743] dyndbg: query 0: "class DRM_UT_ATOMIC +p" mod:drm_kms_helper
[    0.481743] dyndbg: split into words: "class" "DRM_UT_ATOMIC" "+p"
[    0.482743] dyndbg: op='+' flags=0x1 maskp=0xffffffff
[    0.483743] dyndbg: parsed: func="" file="" module="drm_kms_helper" format="" lineno=0-0 class=DRM_UT_ATOMIC
[    0.484750] dyndbg: class-ref: drm_kms_helper.DRM_UT_ATOMIC  module:drm_kms_helper nd:93 nc:0 nu:1
[    0.485809] dyndbg: processed 1 queries, with 44 matches, 0 errs
[    0.486742] dyndbg: bit_4: 44 matches on class: DRM_UT_ATOMIC -> 0x10
[    0.487742] dyndbg: applied bitmap: 0x10 to: 0x0 for drm_kms_helper
[    0.488743] dyndbg: attach-client-module:  module:drm_kms_helper nd:93 nc:0 nu:1
[    0.489742] dyndbg:  93 debug prints in module drm_kms_helper

Widespread testing is appreciated.
I have scripts if anyone wants them.

I'll forward lkp-robot reports here when I get them.

Jim Cromie (25):
  test-dyndbg: fixup CLASSMAP usage error
  dyndbg: reword "class unknown," to "class:_UNKNOWN_"
  dyndbg: make ddebug_class_param union members same size
  dyndbg: replace classmap list with a vector
  dyndbg: ddebug_apply_class_bitmap - add module arg, select on it
  dyndbg: split param_set_dyndbg_classes to module/wrapper fns
  dyndbg: drop NUM_TYPE_ARRAY
  dyndbg: reduce verbose/debug clutter
  dyndbg: silence debugs with no-change updates
  dyndbg: tighten ddebug_class_name() 1st arg type
  dyndbg: tighten fn-sig of ddebug_apply_class_bitmap
  dyndbg: reduce verbose=3 messages in ddebug_add_module
  dyndbg-API: remove DD_CLASS_TYPE_(DISJOINT|LEVEL)_NAMES and code
  dyndbg-API: fix CONFIG_DRM_USE_DYNAMIC_DEBUG regression
  dyndbg: add for_each_boxed_vector
  dyndbg: refactor ddebug_classparam_clamp_input
  dyndbg-API: promote DYNDBG_CLASSMAP_PARAM to API
  dyndbg-doc: add classmap info to howto
  dyndbg: reserve flag bit _DPRINTK_FLAGS_PREFIX_CACHED
  dyndbg: add _DPRINTK_FLAGS_INCL_LOOKUP
  dyndbg: refactor *dynamic_emit_prefix
  dyndbg: improve err report in attach_user_module_classes
  drm: use correct ccflags-y spelling
  drm-drivers: DRM_CLASSMAP_USE in 2nd batch of drivers, helpers
  drm: restore CONFIG_DRM_USE_DYNAMIC_DEBUG un-BROKEN

 .../admin-guide/dynamic-debug-howto.rst       |  59 ++-
 MAINTAINERS                                   |   2 +-
 drivers/gpu/drm/Kconfig                       |   3 +-
 drivers/gpu/drm/Makefile                      |   3 +-
 drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c       |  12 +-
 drivers/gpu/drm/display/drm_dp_helper.c       |  12 +-
 drivers/gpu/drm/drm_crtc_helper.c             |  12 +-
 drivers/gpu/drm/drm_gem_shmem_helper.c        |   2 +
 drivers/gpu/drm/drm_print.c                   |  35 +-
 drivers/gpu/drm/gud/gud_drv.c                 |   2 +
 drivers/gpu/drm/i915/i915_params.c            |  12 +-
 drivers/gpu/drm/mgag200/mgag200_drv.c         |   2 +
 drivers/gpu/drm/nouveau/nouveau_drm.c         |  12 +-
 drivers/gpu/drm/qxl/qxl_drv.c                 |   2 +
 drivers/gpu/drm/radeon/radeon_drv.c           |   2 +
 drivers/gpu/drm/udl/udl_main.c                |   2 +
 drivers/gpu/drm/vkms/vkms_drv.c               |   2 +
 drivers/gpu/drm/vmwgfx/vmwgfx_drv.c           |   2 +
 include/asm-generic/vmlinux.lds.h             |   1 +
 include/drm/drm_print.h                       |  12 +-
 include/linux/dynamic_debug.h                 | 121 +++--
 kernel/module/main.c                          |   3 +
 lib/Kconfig.debug                             |  22 +-
 lib/Makefile                                  |   3 +
 lib/dynamic_debug.c                           | 478 +++++++++++-------
 lib/test_dynamic_debug.c                      | 137 ++---
 lib/test_dynamic_debug_submod.c               |  17 +
 27 files changed, 599 insertions(+), 373 deletions(-)
 create mode 100644 lib/test_dynamic_debug_submod.c

-- 
2.41.0