[PATCH v6 00/57] DYNDBG: opt-in class'd debug for modules, use in drm.

[PATCH v6 00/57] DYNDBG: opt-in class'd debug for modules, use in drm.

[Jim Cromie]

hi Greg, Jason, DRM-folk, Steven,

If Im not too late for linux-next in this cycle, heres V6.  Diffs are minor:

 - rebased onto e47eb90a0a9a (tag: next-20220901, linux-next/master)
   gets past Kconfig conflict, same for drm-tip.
 - uint debug_level, not ulong.  to fit nouveau.
 - -1 on param-read-back, to match prev write val.
 - added back tracefs parts, missing from -V5
   updated for tracing/events: Add __vstring() and __assign_vstr() helper macros
   no decorations-lite in TP_printk, do it right later.
 - commit-msg tweaks

Theres also new RFC stuff with the potential to reduce the size of the
__dyndbgs section by 20%.  Not ready for prime time, or linux-next,
but I hope compelling.

FEATURE DESCRIPTION

dyndbg provides DECLARE_DYNAMIC_DEBUG_CLASSMAP() which allows module
authors to declare "good" class-names, of 4 types.

  DYNAMIC_DEBUG_CLASSMAP(drm_debug_classes,
  			DD_CLASS_TYPE_DISJOINT_BITS, offset,
                        "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");

That usage authorizes dyndbg to set class'd pr_debugs accordingly:

  echo class DRM_UT_CORE +p > /proc/dynamic_debug/control
  echo class DRM_UT_KMS  +p > /proc/dynamic_debug/control

Because the DRM modules declare the same classes, they each authorize
dyndbg with the same classnames, which allows dyndbg to effect changes
to its selected class'd prdbgs.

Opting in by using the macro effectively privatizes the limited
63-classes available per module; only modules which share classnames
must coordinate their use of the common range, and they can
independently use the remaining id-space.

Other dyndbg filtering pertains too, so single sites can be selected.


4 DD_CLASS_TYPE_*_*s determine 2 behaviors:

  DISJOINT	bits are independent, like drm.debug categories
  LEVELs	3>2, turns on level-2, like nouveau debug-levels
  NUM/BITS	numeric input, bitmap if disjoint, else 0-32.
  NAMES		accept proper names, like DRM_UT_CORE

Dyndbg provides param-callbacks which enforce those behaviors:

  # DISJOINT_BITS
  echo 0x03 > /sys/module/drm/parameters/debug

  # LEVEL_NUM
  echo 3 > /sys/module/drm/nouveau/debug-mumble*

  # DISJOINT_NAMES
  echo +DRM_UT_CORE,+DRM_UT_KMS,-DRM_UT_DRIVER > /sys/module/drm/parameters/debug_categories

  # LEVEL_NAMES
  echo NV_TRACE > /sys/module/nouveau/parameters/debug-mumble*

That design choice is allowed cuz verbosity is always attached to a
(user visible) interface, and theres no reason not to put the
implementation there (in the callback).  It also considerably
simplifies things; ddebug_change can treat class_id's as disjoint,
period.


Jim Cromie (57):
prep:
  dyndbg: fix static_branch manipulation
  dyndbg: fix module.dyndbg handling
  dyndbg: show both old and new in change-info
  dyndbg: reverse module walk in cat control
  dyndbg: reverse module.callsite walk in cat control
  dyndbg: use ESCAPE_SPACE for cat control
  dyndbg: let query-modname override actual module name
  dyndbg: add test_dynamic_debug module
  dyndbg: drop EXPORTed dynamic_debug_exec_queries
  dyndbg: cleanup auto vars in dynamic_debug_init
  dyndbg: gather __dyndbg[] state into struct _ddebug_info

class feature:
  dyndbg: add class_id to pr_debug callsites
  dyndbg: add __pr_debug_cls for testing
  dyndbg: add DECLARE_DYNDBG_CLASSMAP macro
  kernel/module: add __dyndbg_classes section
  dyndbg: add ddebug_attach_module_classes
  dyndbg: validate class FOO by checking with module
  doc-dyndbg: describe "class CLASS_NAME" query support
  doc-dyndbg: edit dynamic-debug-howto for brevity, audience
  dyndbg: add drm.debug style (drm/parameters/debug) bitmap support
  dyndbg: test DECLARE_DYNDBG_CLASSMAP, sysfs nodes

drm-use-case:
  drm_print: condense enum drm_debug_category
  drm: POC drm on dyndbg - use in core, 2 helpers, 3 drivers.
  drm_print: interpose drm_*dbg with forwarding macros
  drm_print: wrap drm_*_dbg in dyndbg descriptor factory macro
  drm-print.h: include dyndbg header
  drm-print: add drm_dbg_driver to improve namespace symmetry
  drm_print: refine drm_debug_enabled for jump-label
  drm_print: prefer bare printk KERN_DEBUG on generic fn
  drm_print: add _ddebug descriptor to drm_*dbg prototypes
  nouveau: change nvkm_debug/trace to use dev_dbg POC
  nouveau: adapt NV_DEBUG, NV_ATOMIC to use DRM.debug
  nouveau: WIP add 2 LEVEL_NUM classmaps for CLI, SUBDEV

dyndbg-tracefs:
  dyndbg: add _DPRINTK_FLAGS_ENABLED
  dyndbg: add _DPRINTK_FLAGS_TRACE
  dyndbg: add write-events-to-tracefs code
  dyndbg: add 2 trace-events: drm_debug, drm_devdbg
  dyndbg: add 2 more trace-events: pr_debug, dev_dbg
  dyndbg/drm: POC add tracebits sysfs-knob

RFC-20%-data-reclaim:
  dyndbg: abstraction macros for modname,function,filename fields
  dyndbg: split repeating columns to new struct _ddebug_site
  dyndbg: shrink lineno field by 2 bits
  dyndbg: add _index,_map to struct _ddebug
  dyndbg: extend __ddebug_add_module proto to allow packing sites
  dyndbg: de-duplicate sites
  dyndbg: drop site-> in add-module, more needed
  dyndbg: demote iter->site in _init
  dyndbg: add .gnu.linkonce slot in vmlinux.lds.h KEEPs
  dyndbg: add structs _ddebug_hdr, _ddebug_site_hdr
  dyndbg: count unique callsites
  dyndbg: prevent build bugs via -DNO_DYNAMIC_DEBUG_TABLE
  dyndbg: add DEFINE_DYNAMIC_DEBUG_TABLE, use it tacitly RFC
  dyndbg: add/use is_dyndbg_header then set _uplink
  dyndbg: add .gnu.linkonce. & __dyndbg* sections in module.lds.h
  dyndbg: dynamic_debug_sites_reclaim() using free_reserved_page() WAG
  dyndbg: work ddebug_map_site
  dyndbg: fiddle with readback value on LEVEL_NAMES types

 .../admin-guide/dynamic-debug-howto.rst       | 249 +++---
 MAINTAINERS                                   |   2 +
 arch/arm/boot/compressed/Makefile             |   2 +
 arch/sparc/vdso/Makefile                      |   2 +
 arch/x86/boot/compressed/Makefile             |   1 +
 arch/x86/entry/vdso/Makefile                  |   3 +
 arch/x86/purgatory/Makefile                   |   1 +
 drivers/firmware/efi/libstub/Makefile         |   3 +-
 drivers/gpu/drm/Kconfig                       |  12 +
 drivers/gpu/drm/Makefile                      |   2 +
 drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c       |  14 +
 drivers/gpu/drm/display/drm_dp_helper.c       |  13 +
 drivers/gpu/drm/drm_crtc_helper.c             |  13 +
 drivers/gpu/drm/drm_print.c                   |  83 +-
 drivers/gpu/drm/i915/i915_params.c            |  12 +
 .../gpu/drm/nouveau/include/nvkm/core/debug.h |  16 +
 .../drm/nouveau/include/nvkm/core/subdev.h    |  17 +-
 drivers/gpu/drm/nouveau/nouveau_drm.c         |  20 +
 drivers/gpu/drm/nouveau/nouveau_drv.h         |  16 +-
 drivers/gpu/drm/nouveau/nvkm/core/subdev.c    |  23 +
 include/asm-generic/module.lds.h              |  12 +-
 include/asm-generic/vmlinux.lds.h             |  10 +
 include/drm/drm_print.h                       |  85 +-
 include/linux/dynamic_debug.h                 | 286 ++++++-
 include/trace/events/drm.h                    |  54 ++
 include/trace/events/dyndbg.h                 |  73 ++
 kernel/module/internal.h                      |   4 +-
 kernel/module/main.c                          |  22 +-
 lib/Kconfig.debug                             |  10 +
 lib/Makefile                                  |   1 +
 lib/dynamic_debug.c                           | 792 +++++++++++++++---
 lib/test_dynamic_debug.c                      | 165 ++++
 32 files changed, 1680 insertions(+), 338 deletions(-)
 create mode 100644 include/trace/events/drm.h
 create mode 100644 include/trace/events/dyndbg.h
 create mode 100644 lib/test_dynamic_debug.c

-- 
2.37.2

[PATCH v6 01/57] dyndbg: fix static_branch manipulation

[Jim Cromie]

In https://lore.kernel.org/lkml/20211209150910.GA23668@axis.com/

Vincent's patch commented on, and worked around, a bug toggling
static_branch's, when a 2nd PRINTK-ish flag was added.  The bug
results in a premature static_branch_disable when the 1st of 2 flags
was disabled.

The cited commit computed newflags, but then in the JUMP_LABEL block,
failed to use that result, instead using just one of the terms in it.
Using newflags instead made the code work properly.

This is Vincents test-case, reduced.  It needs the 2nd flag to
demonstrate the bug, but it's explanatory here.

pt_test() {
    echo 5 > /sys/module/dynamic_debug/verbose

    site="module tcp" # just one callsite
    echo " $site =_ " > /proc/dynamic_debug/control # clear it

    # A B ~A ~B
    for flg in +T +p "-T #broke here" -p; do
	echo " $site $flg " > /proc/dynamic_debug/control
    done;

    # A B ~B ~A
    for flg in +T +p "-p #broke here" -T; do
	echo " $site $flg " > /proc/dynamic_debug/control
    done
}
pt_test

Fixes: 84da83a6ffc0 dyndbg: combine flags & mask into a struct, simplify with it
CC: vincent.whitchurch@axis.com
Acked-by: Jason Baron <jbaron@akamai.com>
Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
---
.drop @stable, no exposed bug.
.add jbaron ack
---
 lib/dynamic_debug.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/lib/dynamic_debug.c b/lib/dynamic_debug.c
index dd7f56af9aed..a56c1286ffa4 100644
--- a/lib/dynamic_debug.c
+++ b/lib/dynamic_debug.c
@@ -211,10 +211,11 @@ static int ddebug_change(const struct ddebug_query *query,
 				continue;
 #ifdef CONFIG_JUMP_LABEL
 			if (dp->flags & _DPRINTK_FLAGS_PRINT) {
-				if (!(modifiers->flags & _DPRINTK_FLAGS_PRINT))
+				if (!(newflags & _DPRINTK_FLAGS_PRINT))
 					static_branch_disable(&dp->key.dd_key_true);
-			} else if (modifiers->flags & _DPRINTK_FLAGS_PRINT)
+			} else if (newflags & _DPRINTK_FLAGS_PRINT) {
 				static_branch_enable(&dp->key.dd_key_true);
+			}
 #endif
 			dp->flags = newflags;
 			v4pr_info("changed %s:%d [%s]%s =%s\n",
-- 
2.37.2

[PATCH v6 02/57] dyndbg: fix module.dyndbg handling

[Jim Cromie]

For CONFIG_DYNAMIC_DEBUG=N, the ddebug_dyndbg_module_param_cb()
stub-fn is too permissive:

bash-5.1# modprobe drm JUNKdyndbg
bash-5.1# modprobe drm dyndbgJUNK
[   42.933220] dyndbg param is supported only in CONFIG_DYNAMIC_DEBUG builds
[   42.937484] ACPI: bus type drm_connector registered

This caused no ill effects, because unknown parameters are either
ignored by default with an "unknown parameter" warning, or ignored
because dyndbg allows its no-effect use on non-dyndbg builds.

But since the code has an explicit feedback message, it should be
issued accurately.  Fix with strcmp for exact param-name match.

Reported-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Fixes: b48420c1d301 dynamic_debug: make dynamic-debug work for module initialization
Acked-by: Jason Baron <jbaron@akamai.com>
Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
---
 include/linux/dynamic_debug.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/include/linux/dynamic_debug.h b/include/linux/dynamic_debug.h
index dce631e678dd..f30b01aa9fa4 100644
--- a/include/linux/dynamic_debug.h
+++ b/include/linux/dynamic_debug.h
@@ -201,7 +201,7 @@ static inline int ddebug_remove_module(const char *mod)
 static inline int ddebug_dyndbg_module_param_cb(char *param, char *val,
 						const char *modname)
 {
-	if (strstr(param, "dyndbg")) {
+	if (!strcmp(param, "dyndbg")) {
 		/* avoid pr_warn(), which wants pr_fmt() fully defined */
 		printk(KERN_WARNING "dyndbg param is supported only in "
 			"CONFIG_DYNAMIC_DEBUG builds\n");
-- 
2.37.2

[PATCH v6 03/57] dyndbg: show both old and new in change-info

[Jim Cromie]

print "old => new" flag values to the info("change") message.

no functional change.

Acked-by: Jason Baron <jbaron@akamai.com>
Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
---
 lib/dynamic_debug.c | 11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)

diff --git a/lib/dynamic_debug.c b/lib/dynamic_debug.c
index a56c1286ffa4..8faf584f2f4b 100644
--- a/lib/dynamic_debug.c
+++ b/lib/dynamic_debug.c
@@ -156,7 +156,7 @@ static int ddebug_change(const struct ddebug_query *query,
 	struct ddebug_table *dt;
 	unsigned int newflags;
 	unsigned int nfound = 0;
-	struct flagsbuf fbuf;
+	struct flagsbuf fbuf, nbuf;
 
 	/* search for matching ddebugs */
 	mutex_lock(&ddebug_lock);
@@ -217,11 +217,12 @@ static int ddebug_change(const struct ddebug_query *query,
 				static_branch_enable(&dp->key.dd_key_true);
 			}
 #endif
+			v4pr_info("changed %s:%d [%s]%s %s => %s\n",
+				  trim_prefix(dp->filename), dp->lineno,
+				  dt->mod_name, dp->function,
+				  ddebug_describe_flags(dp->flags, &fbuf),
+				  ddebug_describe_flags(newflags, &nbuf));
 			dp->flags = newflags;
-			v4pr_info("changed %s:%d [%s]%s =%s\n",
-				 trim_prefix(dp->filename), dp->lineno,
-				 dt->mod_name, dp->function,
-				 ddebug_describe_flags(dp->flags, &fbuf));
 		}
 	}
 	mutex_unlock(&ddebug_lock);
-- 
2.37.2

[PATCH v6 04/57] dyndbg: reverse module walk in cat control

[Jim Cromie]

/proc/dynamic_debug/control walks the prdbg catalog in "reverse",
fix this by adding new ddebug_tables to tail of list.

This puts init/main.c entries 1st, which looks more than coincidental.

no functional changes.

Acked-by: Jason Baron <jbaron@akamai.com>
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 8faf584f2f4b..7fb99492c16f 100644
--- a/lib/dynamic_debug.c
+++ b/lib/dynamic_debug.c
@@ -970,7 +970,7 @@ int ddebug_add_module(struct _ddebug *tab, unsigned int n,
 	dt->ddebugs = tab;
 
 	mutex_lock(&ddebug_lock);
-	list_add(&dt->link, &ddebug_tables);
+	list_add_tail(&dt->link, &ddebug_tables);
 	mutex_unlock(&ddebug_lock);
 
 	vpr_info("%3u debug prints in module %s\n", n, dt->mod_name);
-- 
2.37.2

[PATCH v6 05/57] dyndbg: reverse module.callsite walk in cat control

[Jim Cromie]

Walk the module's vector of callsites backwards; ie N..0.  This
"corrects" the backwards appearance of a module's prdbg vector when
walked 0..N.  I think this is due to linker mechanics, which I'm
inclined to treat as immutable, and the order is fixable in display.

No functional changes.

Combined with previous commit, which reversed tables-list, we get:

  :#> head -n7 /proc/dynamic_debug/control
  # filename:lineno [module]function flags format
  init/main.c:1179 [main]initcall_blacklist =_ "blacklisting initcall %s\012"
  init/main.c:1218 [main]initcall_blacklisted =_ "initcall %s blacklisted\012"
  init/main.c:1424 [main]run_init_process =_ "  with arguments:\012"
  init/main.c:1426 [main]run_init_process =_ "    %s\012"
  init/main.c:1427 [main]run_init_process =_ "  with environment:\012"
  init/main.c:1429 [main]run_init_process =_ "    %s\012"

Acked-by: Jason Baron <jbaron@akamai.com>
Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
---
 lib/dynamic_debug.c | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/lib/dynamic_debug.c b/lib/dynamic_debug.c
index 7fb99492c16f..8ff11977b8bd 100644
--- a/lib/dynamic_debug.c
+++ b/lib/dynamic_debug.c
@@ -59,7 +59,7 @@ struct ddebug_query {
 
 struct ddebug_iter {
 	struct ddebug_table *table;
-	unsigned int idx;
+	int idx;
 };
 
 struct flag_settings {
@@ -805,13 +805,12 @@ static struct _ddebug *ddebug_iter_first(struct ddebug_iter *iter)
 {
 	if (list_empty(&ddebug_tables)) {
 		iter->table = NULL;
-		iter->idx = 0;
 		return NULL;
 	}
 	iter->table = list_entry(ddebug_tables.next,
 				 struct ddebug_table, link);
-	iter->idx = 0;
-	return &iter->table->ddebugs[iter->idx];
+	iter->idx = iter->table->num_ddebugs;
+	return &iter->table->ddebugs[--iter->idx];
 }
 
 /*
@@ -824,15 +823,16 @@ static struct _ddebug *ddebug_iter_next(struct ddebug_iter *iter)
 {
 	if (iter->table == NULL)
 		return NULL;
-	if (++iter->idx == iter->table->num_ddebugs) {
+	if (--iter->idx < 0) {
 		/* iterate to next table */
-		iter->idx = 0;
 		if (list_is_last(&iter->table->link, &ddebug_tables)) {
 			iter->table = NULL;
 			return NULL;
 		}
 		iter->table = list_entry(iter->table->link.next,
 					 struct ddebug_table, link);
+		iter->idx = iter->table->num_ddebugs;
+		--iter->idx;
 	}
 	return &iter->table->ddebugs[iter->idx];
 }
-- 
2.37.2

[PATCH v6 06/57] dyndbg: use ESCAPE_SPACE for cat control

[Jim Cromie]

`cat control` currently does octal escape, so '\n' becomes "\012".
Change this to display as "\n" instead, which reads much cleaner.

   :#> head -n7 /proc/dynamic_debug/control
   # filename:lineno [module]function flags format
   init/main.c:1179 [main]initcall_blacklist =_ "blacklisting initcall %s\n"
   init/main.c:1218 [main]initcall_blacklisted =_ "initcall %s blacklisted\n"
   init/main.c:1424 [main]run_init_process =_ "  with arguments:\n"
   init/main.c:1426 [main]run_init_process =_ "    %s\n"
   init/main.c:1427 [main]run_init_process =_ "  with environment:\n"
   init/main.c:1429 [main]run_init_process =_ "    %s\n"

Acked-by: Jason Baron <jbaron@akamai.com>
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 8ff11977b8bd..e5cbe603000c 100644
--- a/lib/dynamic_debug.c
+++ b/lib/dynamic_debug.c
@@ -900,7 +900,7 @@ static int ddebug_proc_show(struct seq_file *m, void *p)
 		   trim_prefix(dp->filename), dp->lineno,
 		   iter->table->mod_name, dp->function,
 		   ddebug_describe_flags(dp->flags, &flags));
-	seq_escape(m, dp->format, "\t\r\n\"");
+	seq_escape_str(m, dp->format, ESCAPE_SPACE, "\t\r\n\"");
 	seq_puts(m, "\"\n");
 
 	return 0;
-- 
2.37.2

[PATCH v6 07/57] dyndbg: let query-modname override actual module name

[Jim Cromie]

dyndbg's control-parser: ddebug_parse_query(), requires that search
terms: module, func, file, lineno, are used only once in a query; a
thing cannot be named both foo and bar.

The cited commit added an overriding module modname, taken from the
module loader, which is authoritative.  So it set query.module 1st,
which disallowed its use in the query-string.

But now, its useful to allow a module-load to enable classes across a
whole (or part of) a subsystem at once.

  # enable (dynamic-debug in) drm only
  modprobe drm dyndbg="class DRM_UT_CORE +p"

  # get drm_helper too
  modprobe drm dyndbg="class DRM_UT_CORE module drm* +p"

  # get everything that knows DRM_UT_CORE
  modprobe drm dyndbg="class DRM_UT_CORE module * +p"

  # also for boot-args:
  drm.dyndbg="class DRM_UT_CORE module * +p"

So convert the override into a default, by filling it only when/after
the query-string omitted the module.

NB: the query class FOO handling is forthcoming.

Fixes: 8e59b5cfb9a6 dynamic_debug: add modname arg to exec_query callchain
Acked-by: Jason Baron <jbaron@akamai.com>
Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
---
 lib/dynamic_debug.c | 11 +++++++----
 1 file changed, 7 insertions(+), 4 deletions(-)

diff --git a/lib/dynamic_debug.c b/lib/dynamic_debug.c
index e5cbe603000c..5a849716220a 100644
--- a/lib/dynamic_debug.c
+++ b/lib/dynamic_debug.c
@@ -385,10 +385,6 @@ static int ddebug_parse_query(char *words[], int nwords,
 		return -EINVAL;
 	}
 
-	if (modname)
-		/* support $modname.dyndbg=<multiple queries> */
-		query->module = modname;
-
 	for (i = 0; i < nwords; i += 2) {
 		char *keyword = words[i];
 		char *arg = words[i+1];
@@ -429,6 +425,13 @@ static int ddebug_parse_query(char *words[], int nwords,
 		if (rc)
 			return rc;
 	}
+	if (!query->module && modname)
+		/*
+		 * support $modname.dyndbg=<multiple queries>, when
+		 * not given in the query itself
+		 */
+		query->module = modname;
+
 	vpr_info_dq(query, "parsed");
 	return 0;
 }
-- 
2.37.2

[PATCH v6 08/57] dyndbg: add test_dynamic_debug module

[Jim Cromie]

Provide a simple module to allow testing DYNAMIC_DEBUG behavior.  It
calls do_prints() from module-init, and with a sysfs-node.

  dmesg -C
  dmesg -w &
  modprobe test_dynamic_debug dyndbg=+p
  echo 1 > /sys/module/dynamic_debug/parameters/verbose

  cat /sys/module/test_dynamic_debug/parameters/do_prints
  echo module test_dynamic_debug +mftl > /proc/dynamic_debug/control
  echo junk > /sys/module/test_dynamic_debug/parameters/do_prints

Acked-by: Jason Baron <jbaron@akamai.com>
Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
---
 MAINTAINERS              |  2 ++
 lib/Kconfig.debug        | 10 ++++++
 lib/Makefile             |  1 +
 lib/test_dynamic_debug.c | 70 ++++++++++++++++++++++++++++++++++++++++
 4 files changed, 83 insertions(+)
 create mode 100644 lib/test_dynamic_debug.c

diff --git a/MAINTAINERS b/MAINTAINERS
index 41762df1be0c..c4465981df31 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -7222,6 +7222,8 @@ M:	Jason Baron <jbaron@akamai.com>
 S:	Maintained
 F:	include/linux/dynamic_debug.h
 F:	lib/dynamic_debug.c
+M:	Jim Cromie <jim.cromie@gmail.com>
+F:	lib/test_dynamic_debug.c
 
 DYNAMIC INTERRUPT MODERATION
 M:	Tal Gilboa <talgi@nvidia.com>
diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index 183c37502119..5bf7897d9095 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -2587,6 +2587,16 @@ config TEST_STATIC_KEYS
 
 	  If unsure, say N.
 
+config TEST_DYNAMIC_DEBUG
+	tristate "Test DYNAMIC_DEBUG"
+	depends on 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.
+
+	  If unsure, say N.
+
 config TEST_KMOD
 	tristate "kmod stress tester"
 	depends on m
diff --git a/lib/Makefile b/lib/Makefile
index f0a855eed891..c893114029b8 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -83,6 +83,7 @@ obj-$(CONFIG_TEST_SORT) += test_sort.o
 obj-$(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_PRINTF) += test_printf.o
 obj-$(CONFIG_TEST_SCANF) += test_scanf.o
 obj-$(CONFIG_TEST_BITMAP) += test_bitmap.o
diff --git a/lib/test_dynamic_debug.c b/lib/test_dynamic_debug.c
new file mode 100644
index 000000000000..ba3882ca3e48
--- /dev/null
+++ b/lib/test_dynamic_debug.c
@@ -0,0 +1,70 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Kernel module for testing dynamic_debug
+ *
+ * Authors:
+ *      Jim Cromie	<jim.cromie@gmail.com>
+ */
+
+#define pr_fmt(fmt) "test_dd: " fmt
+
+#include <linux/module.h>
+
+static void do_prints(void); /* device under test */
+
+/* run tests by reading or writing sysfs node */
+
+static int param_set_do_prints(const char *instr, const struct kernel_param *kp)
+{
+	do_prints();
+	return 0;
+}
+
+static int param_get_do_prints(char *buffer, const struct kernel_param *kp)
+{
+	do_prints();
+	return scnprintf(buffer, PAGE_SIZE, "did do_prints\n");
+}
+
+static const struct kernel_param_ops param_ops_do_prints = {
+	.set = param_set_do_prints,
+	.get = param_get_do_prints,
+};
+
+module_param_cb(do_prints, &param_ops_do_prints, NULL, 0600);
+
+static void do_alpha(void)
+{
+	pr_debug("do alpha\n");
+}
+static void do_beta(void)
+{
+	pr_debug("do beta\n");
+}
+
+static void do_prints(void)
+{
+	do_alpha();
+	do_beta();
+}
+
+static int __init test_dynamic_debug_init(void)
+{
+	pr_debug("init start\n");
+
+	do_prints();
+
+	pr_debug("init done\n");
+	return 0;
+}
+
+static void __exit test_dynamic_debug_exit(void)
+{
+	pr_debug("exiting\n");
+}
+
+module_init(test_dynamic_debug_init);
+module_exit(test_dynamic_debug_exit);
+
+MODULE_AUTHOR("Jim Cromie <jim.cromie@gmail.com>");
+MODULE_LICENSE("GPL");
-- 
2.37.2

[PATCH v6 09/57] dyndbg: drop EXPORTed dynamic_debug_exec_queries

[Jim Cromie]

This exported fn is unused, and will not be needed. Lets dump it.

The export was added to let drm control pr_debugs, as part of using
them to avoid drm_debug_enabled overheads.  But its better to just
implement the drm.debug bitmap interface, then its available for
everyone.

Fixes: a2d375eda771 ("dyndbg: refine export, rename to dynamic_debug_exec_queries()")
Fixes: 4c0d77828d4f ("dyndbg: export ddebug_exec_queries")
Acked-by: Jason Baron <jbaron@akamai.com>
Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
---
 include/linux/dynamic_debug.h |  9 ---------
 lib/dynamic_debug.c           | 29 -----------------------------
 2 files changed, 38 deletions(-)

diff --git a/include/linux/dynamic_debug.h b/include/linux/dynamic_debug.h
index f30b01aa9fa4..8d9eec5f6d8b 100644
--- a/include/linux/dynamic_debug.h
+++ b/include/linux/dynamic_debug.h
@@ -55,9 +55,6 @@ struct _ddebug {
 
 #if defined(CONFIG_DYNAMIC_DEBUG_CORE)
 
-/* exported for module authors to exercise >control */
-int dynamic_debug_exec_queries(const char *query, const char *modname);
-
 int ddebug_add_module(struct _ddebug *tab, unsigned int n,
 				const char *modname);
 extern int ddebug_remove_module(const char *mod_name);
@@ -221,12 +218,6 @@ static inline int ddebug_dyndbg_module_param_cb(char *param, char *val,
 				rowsize, groupsize, buf, len, ascii);	\
 	} while (0)
 
-static inline int dynamic_debug_exec_queries(const char *query, const char *modname)
-{
-	pr_warn("kernel not built with CONFIG_DYNAMIC_DEBUG_CORE\n");
-	return 0;
-}
-
 #endif /* !CONFIG_DYNAMIC_DEBUG_CORE */
 
 #endif
diff --git a/lib/dynamic_debug.c b/lib/dynamic_debug.c
index 5a849716220a..e96dc216463b 100644
--- a/lib/dynamic_debug.c
+++ b/lib/dynamic_debug.c
@@ -558,35 +558,6 @@ static int ddebug_exec_queries(char *query, const char *modname)
 	return nfound;
 }
 
-/**
- * dynamic_debug_exec_queries - select and change dynamic-debug prints
- * @query: query-string described in admin-guide/dynamic-debug-howto
- * @modname: string containing module name, usually &module.mod_name
- *
- * This uses the >/proc/dynamic_debug/control reader, allowing module
- * authors to modify their dynamic-debug callsites. The modname is
- * canonically struct module.mod_name, but can also be null or a
- * module-wildcard, for example: "drm*".
- */
-int dynamic_debug_exec_queries(const char *query, const char *modname)
-{
-	int rc;
-	char *qry; /* writable copy of query */
-
-	if (!query) {
-		pr_err("non-null query/command string expected\n");
-		return -EINVAL;
-	}
-	qry = kstrndup(query, PAGE_SIZE, GFP_KERNEL);
-	if (!qry)
-		return -ENOMEM;
-
-	rc = ddebug_exec_queries(qry, modname);
-	kfree(qry);
-	return rc;
-}
-EXPORT_SYMBOL_GPL(dynamic_debug_exec_queries);
-
 #define PREFIX_SIZE 64
 
 static int remaining(int wrote)
-- 
2.37.2

[PATCH v6 10/57] dyndbg: cleanup auto vars in dynamic_debug_init

[Jim Cromie]

rework var-names for clarity, regularity
rename variables
  - n to mod_sites - it counts sites-per-module
  - entries to i - display only
  - iter_start to iter_mod_start - marks start of each module's subrange
  - modct to mod_ct - stylistic

new iterator var:
  - site - cursor parallel to iter
    1st step towards 'demotion' of iter->site, for removal later

treat vars as iters:
  - drop init at top
    init just above for-loop, in a textual block

Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
---
 lib/dynamic_debug.c | 33 +++++++++++++++++----------------
 1 file changed, 17 insertions(+), 16 deletions(-)

diff --git a/lib/dynamic_debug.c b/lib/dynamic_debug.c
index e96dc216463b..2e8ebef3bd0d 100644
--- a/lib/dynamic_debug.c
+++ b/lib/dynamic_debug.c
@@ -1059,11 +1059,10 @@ static int __init dynamic_debug_init_control(void)
 
 static int __init dynamic_debug_init(void)
 {
-	struct _ddebug *iter, *iter_start;
-	const char *modname = NULL;
+	struct _ddebug *iter, *iter_mod_start;
+	int ret, i, mod_sites, mod_ct;
+	const char *modname;
 	char *cmdline;
-	int ret = 0;
-	int n = 0, entries = 0, modct = 0;
 
 	if (&__start___dyndbg == &__stop___dyndbg) {
 		if (IS_ENABLED(CONFIG_DYNAMIC_DEBUG)) {
@@ -1074,30 +1073,32 @@ static int __init dynamic_debug_init(void)
 		ddebug_init_success = 1;
 		return 0;
 	}
-	iter = __start___dyndbg;
+
+	iter = iter_mod_start = __start___dyndbg;
 	modname = iter->modname;
-	iter_start = iter;
-	for (; iter < __stop___dyndbg; iter++) {
-		entries++;
+	i = mod_sites = mod_ct = 0;
+
+	for (; iter < __stop___dyndbg; iter++, i++, mod_sites++) {
+
 		if (strcmp(modname, iter->modname)) {
-			modct++;
-			ret = ddebug_add_module(iter_start, n, modname);
+			mod_ct++;
+			ret = ddebug_add_module(iter_mod_start, mod_sites, modname);
 			if (ret)
 				goto out_err;
-			n = 0;
+
+			mod_sites = 0;
 			modname = iter->modname;
-			iter_start = iter;
+			iter_mod_start = iter;
 		}
-		n++;
 	}
-	ret = ddebug_add_module(iter_start, n, modname);
+	ret = ddebug_add_module(iter_mod_start, mod_sites, modname);
 	if (ret)
 		goto out_err;
 
 	ddebug_init_success = 1;
 	vpr_info("%d prdebugs in %d modules, %d KiB in ddebug tables, %d kiB in __dyndbg section\n",
-		 entries, modct, (int)((modct * sizeof(struct ddebug_table)) >> 10),
-		 (int)((entries * sizeof(struct _ddebug)) >> 10));
+		 i, mod_ct, (int)((mod_ct * sizeof(struct ddebug_table)) >> 10),
+		 (int)((i * sizeof(struct _ddebug)) >> 10));
 
 	/* now that ddebug tables are loaded, process all boot args
 	 * again to find and activate queries given in dyndbg params.
-- 
2.37.2

[PATCH v6 11/57] dyndbg: gather __dyndbg[] state into struct _ddebug_info

[Jim Cromie]

This new struct composes the linker provided (vector,len) section,
and provides a place to add other __dyndbg[] state-data later:

  descs - the vector of descriptors in __dyndbg section.
  num_descs - length of the data/section.

Use it, in several different ways, as follows:

In lib/dynamic_debug.c:

ddebug_add_module(): Alter params-list, replacing 2 args (array,index)
with a struct _ddebug_info * containing them both, with room for
expansion.  This helps future-proof the function prototype against the
looming addition of class-map info into the dyndbg-state, by providing
a place to add more member fields later.

NB: later add static struct _ddebug_info builtins_state declaration,
not needed yet.

ddebug_add_module() is called in 2 contexts:

In dynamic_debug_init(), declare, init a struct _ddebug_info di
auto-var to use as a cursor.  Then iterate over the prdbg blocks of
the builtin modules, and update the di cursor before calling
_add_module for each.

Its called from kernel/module/main.c:load_info() for each loaded
module:

In internal.h, alter struct load_info, replacing the dyndbg array,len
fields with an embedded _ddebug_info containing them both; and
populate its members in find_module_sections().

The 2 calling contexts differ in that _init deals with contiguous
subranges of __dyndbgs[] section, packed together, while loadable
modules are added one at a time.

So rename ddebug_add_module() into outer/__inner fns, call __inner
from _init, and provide the offset into the builtin __dyndbgs[] where
the module's prdbgs reside.  The cursor provides start, len of the
subrange for each.  The offset will be used later to pack the results
of builtin __dyndbg_sites[] de-duplication, and is 0 and unneeded for
loadable modules,

Note:

kernel/module/main.c includes <dynamic_debug.h> for struct
_ddeubg_info.  This might be prone to include loops, since its also
included by printk.h.  Nothing has broken in robot-land on this.

cc: Luis Chamberlain <mcgrof@kernel.org>
Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
---
 include/linux/dynamic_debug.h | 13 +++++++-----
 kernel/module/internal.h      |  4 ++--
 kernel/module/main.c          | 18 ++++++++--------
 lib/dynamic_debug.c           | 40 +++++++++++++++++++++++++++--------
 4 files changed, 50 insertions(+), 25 deletions(-)

diff --git a/include/linux/dynamic_debug.h b/include/linux/dynamic_debug.h
index 8d9eec5f6d8b..6a2001250da1 100644
--- a/include/linux/dynamic_debug.h
+++ b/include/linux/dynamic_debug.h
@@ -51,12 +51,16 @@ struct _ddebug {
 #endif
 } __attribute__((aligned(8)));
 
-
+/* encapsulate linker provided built-in (or module) dyndbg data */
+struct _ddebug_info {
+	struct _ddebug *descs;
+	unsigned int num_descs;
+};
 
 #if defined(CONFIG_DYNAMIC_DEBUG_CORE)
 
-int ddebug_add_module(struct _ddebug *tab, unsigned int n,
-				const char *modname);
+int ddebug_add_module(struct _ddebug_info *dyndbg, const char *modname);
+
 extern int ddebug_remove_module(const char *mod_name);
 extern __printf(2, 3)
 void __dynamic_pr_debug(struct _ddebug *descriptor, const char *fmt, ...);
@@ -184,8 +188,7 @@ void __dynamic_ibdev_dbg(struct _ddebug *descriptor,
 #include <linux/errno.h>
 #include <linux/printk.h>
 
-static inline int ddebug_add_module(struct _ddebug *tab, unsigned int n,
-				    const char *modname)
+static inline int ddebug_add_module(struct _ddebug_info *dinfo, const char *modname)
 {
 	return 0;
 }
diff --git a/kernel/module/internal.h b/kernel/module/internal.h
index 680d980a4fb2..2e2bf236f558 100644
--- a/kernel/module/internal.h
+++ b/kernel/module/internal.h
@@ -53,6 +53,7 @@ extern const struct kernel_symbol __stop___ksymtab_gpl[];
 extern const s32 __start___kcrctab[];
 extern const s32 __start___kcrctab_gpl[];
 
+#include <linux/dynamic_debug.h>
 struct load_info {
 	const char *name;
 	/* pointer to module in temporary copy, freed at end of load_module() */
@@ -62,8 +63,7 @@ struct load_info {
 	Elf_Shdr *sechdrs;
 	char *secstrings, *strtab;
 	unsigned long symoffs, stroffs, init_typeoffs, core_typeoffs;
-	struct _ddebug *debug;
-	unsigned int num_debug;
+	struct _ddebug_info dyndbg;
 	bool sig_ok;
 #ifdef CONFIG_KALLSYMS
 	unsigned long mod_kallsyms_init_off;
diff --git a/kernel/module/main.c b/kernel/module/main.c
index a4e4d84b6f4e..4c20bc3ff203 100644
--- a/kernel/module/main.c
+++ b/kernel/module/main.c
@@ -1598,16 +1598,16 @@ static void free_modinfo(struct module *mod)
 	}
 }
 
-static void dynamic_debug_setup(struct module *mod, struct _ddebug *debug, unsigned int num)
+static void dynamic_debug_setup(struct module *mod, struct _ddebug_info *dyndbg)
 {
-	if (!debug)
+	if (!dyndbg->num_descs)
 		return;
-	ddebug_add_module(debug, num, mod->name);
+	ddebug_add_module(dyndbg, mod->name);
 }
 
-static void dynamic_debug_remove(struct module *mod, struct _ddebug *debug)
+static void dynamic_debug_remove(struct module *mod, struct _ddebug_info *dyndbg)
 {
-	if (debug)
+	if (dyndbg->num_descs)
 		ddebug_remove_module(mod->name);
 }
 
@@ -2111,8 +2111,8 @@ static int find_module_sections(struct module *mod, struct load_info *info)
 	if (section_addr(info, "__obsparm"))
 		pr_warn("%s: Ignoring obsolete parameters\n", mod->name);
 
-	info->debug = section_objs(info, "__dyndbg",
-				   sizeof(*info->debug), &info->num_debug);
+	info->dyndbg.descs = section_objs(info, "__dyndbg",
+					sizeof(*info->dyndbg.descs), &info->dyndbg.num_descs);
 
 	return 0;
 }
@@ -2807,7 +2807,7 @@ static int load_module(struct load_info *info, const char __user *uargs,
 	}
 
 	init_build_id(mod, info);
-	dynamic_debug_setup(mod, info->debug, info->num_debug);
+	dynamic_debug_setup(mod, &info->dyndbg);
 
 	/* Ftrace init must be called in the MODULE_STATE_UNFORMED state */
 	ftrace_module_init(mod);
@@ -2871,7 +2871,7 @@ static int load_module(struct load_info *info, const char __user *uargs,
 
  ddebug_cleanup:
 	ftrace_release_mod(mod);
-	dynamic_debug_remove(mod, info->debug);
+	dynamic_debug_remove(mod, &info->dyndbg);
 	synchronize_rcu();
 	kfree(mod->args);
  free_arch_cleanup:
diff --git a/lib/dynamic_debug.c b/lib/dynamic_debug.c
index 2e8ebef3bd0d..c358ccdf4a39 100644
--- a/lib/dynamic_debug.c
+++ b/lib/dynamic_debug.c
@@ -923,14 +923,20 @@ static const struct proc_ops proc_fops = {
  * Allocate a new ddebug_table for the given module
  * and add it to the global list.
  */
-int ddebug_add_module(struct _ddebug *tab, unsigned int n,
-			     const char *name)
+static int __ddebug_add_module(struct _ddebug_info *di, unsigned int base,
+			       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);
+		return 0;
+	}
+
 	dt = kzalloc(sizeof(*dt), GFP_KERNEL);
 	if (dt == NULL) {
-		pr_err("error adding module: %s\n", name);
+		pr_err("error adding module: %s\n", modname);
 		return -ENOMEM;
 	}
 	/*
@@ -939,18 +945,25 @@ int ddebug_add_module(struct _ddebug *tab, unsigned int n,
 	 * member of struct module, which lives at least as long as
 	 * this struct ddebug_table.
 	 */
-	dt->mod_name = name;
-	dt->num_ddebugs = n;
-	dt->ddebugs = tab;
+	dt->mod_name = modname;
+	dt->ddebugs = di->descs;
+	dt->num_ddebugs = di->num_descs;
+
+	INIT_LIST_HEAD(&dt->link);
 
 	mutex_lock(&ddebug_lock);
 	list_add_tail(&dt->link, &ddebug_tables);
 	mutex_unlock(&ddebug_lock);
 
-	vpr_info("%3u debug prints in module %s\n", n, dt->mod_name);
+	vpr_info("%3u debug prints in module %s\n", di->num_descs, modname);
 	return 0;
 }
 
+int ddebug_add_module(struct _ddebug_info *di, const char *modname)
+{
+	return __ddebug_add_module(di, 0, modname);
+}
+
 /* helper for ddebug_dyndbg_(boot|module)_param_cb */
 static int ddebug_dyndbg_param_cb(char *param, char *val,
 				const char *modname, int on_err)
@@ -1064,6 +1077,11 @@ static int __init dynamic_debug_init(void)
 	const char *modname;
 	char *cmdline;
 
+	struct _ddebug_info di = {
+		.descs = __start___dyndbg,
+		.num_descs = __stop___dyndbg - __start___dyndbg,
+	};
+
 	if (&__start___dyndbg == &__stop___dyndbg) {
 		if (IS_ENABLED(CONFIG_DYNAMIC_DEBUG)) {
 			pr_warn("_ddebug table is empty in a CONFIG_DYNAMIC_DEBUG build\n");
@@ -1082,7 +1100,9 @@ static int __init dynamic_debug_init(void)
 
 		if (strcmp(modname, iter->modname)) {
 			mod_ct++;
-			ret = ddebug_add_module(iter_mod_start, mod_sites, modname);
+			di.num_descs = mod_sites;
+			di.descs = iter_mod_start;
+			ret = __ddebug_add_module(&di, i - mod_sites, modname);
 			if (ret)
 				goto out_err;
 
@@ -1091,7 +1111,9 @@ static int __init dynamic_debug_init(void)
 			iter_mod_start = iter;
 		}
 	}
-	ret = ddebug_add_module(iter_mod_start, mod_sites, modname);
+	di.num_descs = mod_sites;
+	di.descs = iter_mod_start;
+	ret = __ddebug_add_module(&di, i - mod_sites, modname);
 	if (ret)
 		goto out_err;
 
-- 
2.37.2

[PATCH v6 12/57] dyndbg: add class_id to pr_debug callsites

[Jim Cromie]

DRM issues ~10 exclusive categories of debug messages; to represent
this directly in dyndbg, add a new 6-bit field: struct _ddebug.class_id.
This gives us 64 classes, which should be more than enough.

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

All existing callsites are initialized with _DPRINTK_CLASS_DFLT, which
is 2^6-1.  This reserves 0-62 for use in new categorized/class'd
pr_debugs, which fits perfectly with natural enums (ints: 0..N).

Thats done by extending the init macro: DEFINE_DYNAMIC_DEBUG_METADATA()
with _CLS(cls, ...) suffix, and redefing old name using extended name.

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

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

No behavior change.

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

diff --git a/include/linux/dynamic_debug.h b/include/linux/dynamic_debug.h
index 6a2001250da1..633f4e463766 100644
--- a/include/linux/dynamic_debug.h
+++ b/include/linux/dynamic_debug.h
@@ -6,6 +6,8 @@
 #include <linux/jump_label.h>
 #endif
 
+#include <linux/build_bug.h>
+
 /*
  * An instance of this structure is created in a special
  * ELF section at every dynamic debug callsite.  At runtime,
@@ -21,6 +23,9 @@ struct _ddebug {
 	const char *filename;
 	const char *format;
 	unsigned int lineno:18;
+#define CLS_BITS 6
+	unsigned int class_id:CLS_BITS;
+#define _DPRINTK_CLASS_DFLT		((1 << CLS_BITS) - 1)
 	/*
 	 * The flags field controls the behaviour at the callsite.
 	 * The bits here are changed dynamically when the user
@@ -88,7 +93,7 @@ void __dynamic_ibdev_dbg(struct _ddebug *descriptor,
 			 const struct ib_device *ibdev,
 			 const char *fmt, ...);
 
-#define DEFINE_DYNAMIC_DEBUG_METADATA(name, fmt)		\
+#define DEFINE_DYNAMIC_DEBUG_METADATA_CLS(name, cls, fmt)	\
 	static struct _ddebug  __aligned(8)			\
 	__section("__dyndbg") name = {				\
 		.modname = KBUILD_MODNAME,			\
@@ -97,8 +102,14 @@ void __dynamic_ibdev_dbg(struct _ddebug *descriptor,
 		.format = (fmt),				\
 		.lineno = __LINE__,				\
 		.flags = _DPRINTK_FLAGS_DEFAULT,		\
+		.class_id = cls,				\
 		_DPRINTK_KEY_INIT				\
-	}
+	};							\
+	BUILD_BUG_ON_MSG(cls > _DPRINTK_CLASS_DFLT,		\
+			 "classid value overflow")
+
+#define DEFINE_DYNAMIC_DEBUG_METADATA(name, fmt)		\
+	DEFINE_DYNAMIC_DEBUG_METADATA_CLS(name, _DPRINTK_CLASS_DFLT, fmt)
 
 #ifdef CONFIG_JUMP_LABEL
 
@@ -129,17 +140,34 @@ void __dynamic_ibdev_dbg(struct _ddebug *descriptor,
 
 #endif /* CONFIG_JUMP_LABEL */
 
-#define __dynamic_func_call(id, fmt, func, ...) do {	\
-	DEFINE_DYNAMIC_DEBUG_METADATA(id, fmt);		\
-	if (DYNAMIC_DEBUG_BRANCH(id))			\
-		func(&id, ##__VA_ARGS__);		\
-} while (0)
-
-#define __dynamic_func_call_no_desc(id, fmt, func, ...) do {	\
-	DEFINE_DYNAMIC_DEBUG_METADATA(id, fmt);			\
+/*
+ * Factory macros: ($prefix)dynamic_func_call($suffix)
+ *
+ * Lower layer (with __ prefix) gets the callsite metadata, and wraps
+ * the func inside a debug-branch/static-key construct.  Upper layer
+ * (with _ prefix) does the UNIQUE_ID once, so that lower can ref the
+ * name/label multiple times, and tie the elements together.
+ * Multiple flavors:
+ * (|_cls):	adds in _DPRINT_CLASS_DFLT as needed
+ * (|_no_desc):	former gets callsite descriptor as 1st arg (for prdbgs)
+ */
+#define __dynamic_func_call_cls(id, cls, fmt, func, ...) do {	\
+	DEFINE_DYNAMIC_DEBUG_METADATA_CLS(id, cls, fmt);	\
 	if (DYNAMIC_DEBUG_BRANCH(id))				\
-		func(__VA_ARGS__);				\
+		func(&id, ##__VA_ARGS__);			\
 } while (0)
+#define __dynamic_func_call(id, fmt, func, ...)				\
+	__dynamic_func_call_cls(id, _DPRINTK_CLASS_DFLT, fmt,		\
+				func, ##__VA_ARGS__)
+
+#define __dynamic_func_call_cls_no_desc(id, cls, fmt, func, ...) do {	\
+	DEFINE_DYNAMIC_DEBUG_METADATA_CLS(id, cls, fmt);		\
+	if (DYNAMIC_DEBUG_BRANCH(id))					\
+		func(__VA_ARGS__);					\
+} while (0)
+#define __dynamic_func_call_no_desc(id, fmt, func, ...)			\
+	__dynamic_func_call_cls_no_desc(id, _DPRINTK_CLASS_DFLT,	\
+					fmt, func, ##__VA_ARGS__)
 
 /*
  * "Factory macro" for generating a call to func, guarded by a
@@ -149,22 +177,33 @@ void __dynamic_ibdev_dbg(struct _ddebug *descriptor,
  * the varargs. Note that fmt is repeated in invocations of this
  * macro.
  */
+#define _dynamic_func_call_cls(cls, fmt, func, ...)			\
+	__dynamic_func_call_cls(__UNIQUE_ID(ddebug), cls, fmt, func, ##__VA_ARGS__)
 #define _dynamic_func_call(fmt, func, ...)				\
-	__dynamic_func_call(__UNIQUE_ID(ddebug), fmt, func, ##__VA_ARGS__)
+	_dynamic_func_call_cls(_DPRINTK_CLASS_DFLT, fmt, func, ##__VA_ARGS__)
+
 /*
  * A variant that does the same, except that the descriptor is not
  * passed as the first argument to the function; it is only called
  * with precisely the macro's varargs.
  */
-#define _dynamic_func_call_no_desc(fmt, func, ...)	\
-	__dynamic_func_call_no_desc(__UNIQUE_ID(ddebug), fmt, func, ##__VA_ARGS__)
+#define _dynamic_func_call_cls_no_desc(cls, fmt, func, ...)		\
+	__dynamic_func_call_cls_no_desc(__UNIQUE_ID(ddebug), cls, fmt,	\
+					func, ##__VA_ARGS__)
+#define _dynamic_func_call_no_desc(fmt, func, ...)			\
+	_dynamic_func_call_cls_no_desc(_DPRINTK_CLASS_DFLT, fmt,	\
+				       func, ##__VA_ARGS__)
+
+#define dynamic_pr_debug_cls(cls, fmt, ...)				\
+	_dynamic_func_call_cls(cls, fmt, __dynamic_pr_debug,		\
+			   pr_fmt(fmt), ##__VA_ARGS__)
 
 #define dynamic_pr_debug(fmt, ...)				\
-	_dynamic_func_call(fmt,	__dynamic_pr_debug,		\
+	_dynamic_func_call(fmt, __dynamic_pr_debug,		\
 			   pr_fmt(fmt), ##__VA_ARGS__)
 
 #define dynamic_dev_dbg(dev, fmt, ...)				\
-	_dynamic_func_call(fmt,__dynamic_dev_dbg, 		\
+	_dynamic_func_call(fmt, __dynamic_dev_dbg, 		\
 			   dev, fmt, ##__VA_ARGS__)
 
 #define dynamic_netdev_dbg(dev, fmt, ...)			\
-- 
2.37.2

[PATCH v6 13/57] dyndbg: add __pr_debug_cls for testing

[Jim Cromie]

For selftest purposes, add __pr_debug_cls(class, fmt, ...)

I didn't think we'd need to define this, since DRM effectively has it
already in drm_dbg, drm_devdbg.  But test_dynamic_debug needs it in
order to demonstrate all the moving parts.

Note the __ prefix; its not intended for general use, at least until a
need emerges.  ISTM the drm.debug model (macro wrappers inserting enum
const 1st arg) is the baseline approach.

That said, nouveau might want it for easy use in its debug macros. TBD.

NB: it does require a builtin-constant class, __pr_debug_cls(i++, ...)
is disallowed by compiler.

Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
---
 include/linux/dynamic_debug.h | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/include/linux/dynamic_debug.h b/include/linux/dynamic_debug.h
index 633f4e463766..3c9690da44d9 100644
--- a/include/linux/dynamic_debug.h
+++ b/include/linux/dynamic_debug.h
@@ -221,6 +221,13 @@ void __dynamic_ibdev_dbg(struct _ddebug *descriptor,
 				   KERN_DEBUG, prefix_str, prefix_type,	\
 				   rowsize, groupsize, buf, len, ascii)
 
+/* for test only, generally expect drm.debug style macro wrappers */
+#define __pr_debug_cls(cls, fmt, ...) do {			\
+	BUILD_BUG_ON_MSG(!__builtin_constant_p(cls),		\
+			 "expecting constant class int/enum");	\
+	dynamic_pr_debug_cls(cls, fmt, ##__VA_ARGS__);		\
+	} while (0)
+
 #else /* !CONFIG_DYNAMIC_DEBUG_CORE */
 
 #include <linux/string.h>
-- 
2.37.2

[PATCH v6 14/57] dyndbg: add DECLARE_DYNDBG_CLASSMAP macro

[Jim Cromie]

Using DECLARE_DYNDBG_CLASSMAP, modules can declare up to 31 classnames.
By doing so, they authorize dyndbg to manipulate class'd prdbgs (ie:
__pr_debug_cls, and soon drm_*dbg), ala::

   :#> echo class DRM_UT_KMS +p > /proc/dynamic_debug/control

The macro declares and initializes a static struct ddebug_class_map::

 - maps approved class-names to class_ids used in module,
   by array order. forex: DRM_UT_*
 - class-name vals allow validation of "class FOO" queries
   using macro is opt-in
 - enum class_map_type - determines interface, behavior

Each module has its own class-type and class_id space, and only known
class-names will be authorized for a manipulation.  Only DRM modules
should know and respont to this:

  :#> echo class DRM_UT_CORE +p > control	# across all modules

pr_debugs (with default class_id) are still controllable as before.

DECLARE_DYNDBG_CLASSMAP(_var, _maptype, _base, classes...) is::

 _var: name of the static struct var. user passes to module_param_cb()
       if they want a sysfs node.

 _maptype: this is hard-coded to DD_CLASS_TYPE_DISJOINT_BITS for now.

 _base: usually 0, it allows splitting 31 classes into subranges, so
 	that multiple classes / sysfs-nodes can share the module's
 	class-id space.

 classes: list of class_name strings, these are mapped to class-ids
 	  starting at _base.  This class-names list must have a
 	  corresponding ENUM, with SYMBOLS that match the literals,
 	  and 1st enum val = _base.

enum class_map_type has 4 values, on 2 factors::

 - classes are disjoint/independent vs relative/x<y/verbosity.
   disjoint is basis, verbosity by overlay.

 - input NUMBERS vs [+-]CLASS_NAMES
   uints, ideally hex.  vs  +DRM_UT_CORE,-DRM_UT_KMS

DD_CLASS_TYPE_DISJOINT_BITS: classes are separate, one per bit.
   expecting hex input. built for drm.debug, basis for other types.

DD_CLASS_TYPE_DISJOINT_NAMES: input is a CSV of [+-]CLASS_NAMES,
   classes are independent, like DISJOINT

DD_CLASS_TYPE_LEVEL_NUM: input is numeric level, 0-N.
   0 implies silence. use printk to break that.
   relative levels applied on bitmaps.

DD_CLASS_TYPE_LEVEL_NAMES: input is a CSV of [+-]CLASS_NAMES,
   names like: ERR,WARNING,NOTICE,INFO,DEBUG
   avoiding EMERG,ALERT,CRIT,ERR - no point.

NOTES:

The macro places the initialized struct ddebug_class_map into the
__dyndbg_classes section.  That draws an 'orphan' warning which we
handle in the next commit.  The struct attributes are necessary:
__aligned(8) fixed null-ptr derefs, and __used is needed by drm
drivers, which declare class-maps, but don't also declare a
sysfs-param, and thus dont ref the classmap.  The __used insures that
the linkage is made, then the class-map is found at load-time.

While its possible to handle both NAMES and NUMBERS in the same
sys-interface, there is ambiguity to avoid, by disallowing them
together.  Later, if ambiguities are resolved, 2 new enums can permit
both inputs, on verbose & independent types separately, and authors
can select the interface style they like.

The plan is to implement LEVELS in the callbacks, outside of
ddebug_exec_query(), which for simplicity will treat the CLASSES in
the map as disjoint.  The callbacks can see map-type, and apply ++/--
loops (or bitops) to force the relative meanings across the
class-bitmap.

RFC: That leaves 2 issues:

1. doing LEVELs in callbacks means that the native >control interface
doesn't enforce the LEVELS relationship, so you could confusingly have
V3 enabled, but V1 disabled.  OTOH, the control iface already allows
infinite tweaking of the underlying callsites; sysfs node readback can
only tell the user what they previously wrote.

2. All dyndbg >control reduces to a query/command, includes +/-, which
is at-root a kernel patching operation with +/- semantics.  And the
_NAMES handling exposes it to the user, making it API-adjacent.

And its not just >control where +/- gets used (which is settled), the
new place is with sysfs-nodes exposing _*_NAMES classes, and here its
subtly different.

_DISJOINT_NAMES: is simple, independent
_LEVEL_NAMES: masks-on bits 0 .. N-1, N..max off

  # turn on L3,L2,L1 others off
  echo +L3 > /sys/module/test_dynamic_debug/parameters/p_level_names

  # turn on L2,L1 others off
  echo -L3 > /sys/module/test_dynamic_debug/parameters/p_level_names

IOW, the - changes the threshold-on bitpos by 1.

Alternatively, we could treat the +/- as half-duplex, where -L3 turns
off L>2 (and ignores L1), and +L2 would turn on L<=2 (and ignore others).

Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
---
. revised DD_CLASS_TYPE_{DISJOINT,LEVEL}_* names
. reorder-enum - _NAMES feature is extra.
---
 include/linux/dynamic_debug.h | 55 +++++++++++++++++++++++++++++++++++
 1 file changed, 55 insertions(+)

diff --git a/include/linux/dynamic_debug.h b/include/linux/dynamic_debug.h
index 3c9690da44d9..98dbf1d49984 100644
--- a/include/linux/dynamic_debug.h
+++ b/include/linux/dynamic_debug.h
@@ -56,6 +56,61 @@ struct _ddebug {
 #endif
 } __attribute__((aligned(8)));
 
+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_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
+	 */
+};
+
+struct ddebug_class_map {
+	struct list_head link;
+	struct module *mod;
+	const char *mod_name;	/* needed for builtins */
+	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;
+};
+
+/**
+ * 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
+ */
+#define DECLARE_DYNDBG_CLASSMAP(_var, _maptype, _base, ...)		\
+	static const char *_var##_classnames[] = { __VA_ARGS__ };	\
+	static struct ddebug_class_map __aligned(8) __used		\
+		__section("__dyndbg_classes") _var = {			\
+		.mod = THIS_MODULE,					\
+		.mod_name = KBUILD_MODNAME,				\
+		.base = _base,						\
+		.map_type = _maptype,					\
+		.length = NUM_TYPE_ARGS(char*, __VA_ARGS__),		\
+		.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 {
 	struct _ddebug *descs;
-- 
2.37.2

[PATCH v6 15/57] kernel/module: add __dyndbg_classes section

[Jim Cromie]

Add __dyndbg_classes section, using __dyndbg as a model. Use it:

vmlinux.lds.h:

KEEP the new section, which also silences orphan section warning on
loadable modules.  Add (__start_/__stop_)__dyndbg_classes linker
symbols for the c externs (below).

kernel/module/main.c:
- fill new fields in find_module_sections(), using section_objs()
- extend callchain prototypes
  to pass classes, length
  load_module(): pass new info to dynamic_debug_setup()
  dynamic_debug_setup(): new params, pass through to ddebug_add_module()

dynamic_debug.c:
- add externs to the linker symbols.

ddebug_add_module():
- It currently builds a debug_table, and *will* find and attach classes.

dynamic_debug_init():
- add class fields to the _ddebug_info cursor var: di.

Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
---
 include/asm-generic/vmlinux.lds.h | 3 +++
 include/linux/dynamic_debug.h     | 2 ++
 kernel/module/main.c              | 2 ++
 lib/dynamic_debug.c               | 7 +++++++
 4 files changed, 14 insertions(+)

diff --git a/include/asm-generic/vmlinux.lds.h b/include/asm-generic/vmlinux.lds.h
index 7515a465ec03..9b8bd5504ad9 100644
--- a/include/asm-generic/vmlinux.lds.h
+++ b/include/asm-generic/vmlinux.lds.h
@@ -345,6 +345,9 @@
 	*(__tracepoints)						\
 	/* implement dynamic printk debug */				\
 	. = ALIGN(8);							\
+	__start___dyndbg_classes = .;					\
+	KEEP(*(__dyndbg_classes))					\
+	__stop___dyndbg_classes = .;					\
 	__start___dyndbg = .;						\
 	KEEP(*(__dyndbg))						\
 	__stop___dyndbg = .;						\
diff --git a/include/linux/dynamic_debug.h b/include/linux/dynamic_debug.h
index 98dbf1d49984..9073a43a2039 100644
--- a/include/linux/dynamic_debug.h
+++ b/include/linux/dynamic_debug.h
@@ -114,7 +114,9 @@ struct ddebug_class_map {
 /* encapsulate linker provided built-in (or module) dyndbg data */
 struct _ddebug_info {
 	struct _ddebug *descs;
+	struct ddebug_class_map *classes;
 	unsigned int num_descs;
+	unsigned int num_classes;
 };
 
 #if defined(CONFIG_DYNAMIC_DEBUG_CORE)
diff --git a/kernel/module/main.c b/kernel/module/main.c
index 4c20bc3ff203..6aa6153aa6e0 100644
--- a/kernel/module/main.c
+++ b/kernel/module/main.c
@@ -2113,6 +2113,8 @@ static int find_module_sections(struct module *mod, struct load_info *info)
 
 	info->dyndbg.descs = section_objs(info, "__dyndbg",
 					sizeof(*info->dyndbg.descs), &info->dyndbg.num_descs);
+	info->dyndbg.classes = section_objs(info, "__dyndbg_classes",
+					sizeof(*info->dyndbg.classes), &info->dyndbg.num_classes);
 
 	return 0;
 }
diff --git a/lib/dynamic_debug.c b/lib/dynamic_debug.c
index c358ccdf4a39..fb31a1a2fc3f 100644
--- a/lib/dynamic_debug.c
+++ b/lib/dynamic_debug.c
@@ -41,6 +41,8 @@
 
 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[];
 
 struct ddebug_table {
 	struct list_head link;
@@ -1079,7 +1081,9 @@ static int __init dynamic_debug_init(void)
 
 	struct _ddebug_info di = {
 		.descs = __start___dyndbg,
+		.classes = __start___dyndbg_classes,
 		.num_descs = __stop___dyndbg - __start___dyndbg,
+		.num_classes = __stop___dyndbg_classes - __start___dyndbg_classes,
 	};
 
 	if (&__start___dyndbg == &__stop___dyndbg) {
@@ -1122,6 +1126,9 @@ static int __init dynamic_debug_init(void)
 		 i, mod_ct, (int)((mod_ct * sizeof(struct ddebug_table)) >> 10),
 		 (int)((i * sizeof(struct _ddebug)) >> 10));
 
+	if (di.num_classes)
+		v2pr_info("  %d builtin ddebug class-maps\n", di.num_classes);
+
 	/* now that ddebug tables are loaded, process all boot args
 	 * again to find and activate queries given in dyndbg params.
 	 * While this has already been done for known boot params, it
-- 
2.37.2

[PATCH v6 16/57] dyndbg: add ddebug_attach_module_classes

[Jim Cromie]

Add ddebug_attach_module_classes(), call it from ddebug_add_module().
It scans the classes/section its given, finds records where the
module-name matches the module being added, and adds them to the
module's maps list.  No locking here, since the record
isn't yet linked into the ddebug_tables list.

It is called indirectly from 2 sources:

 - from load_module(), where it scans the module's __dyndbg_classes
   section, which contains DYNAMIC_DEBUG_CLASSES definitions from just
   the module.

 - from dynamic_debug_init(), where all DYNAMIC_DEBUG_CLASSES
   definitions of each builtin module have been packed together.
   This is why ddebug_attach_module_classes() checks module-name.

NOTES

Its (highly) likely that builtin classes will be ordered by module
name (just like prdbg descriptors are in the __dyndbg section).  So
the list can be replaced by a vector (ptr + length), which will work
for loaded modules too.  This would imitate whats currently done for
the _ddebug descriptors.

That said, converting to vector,len is close to pointless; a small
minority of modules will ever define a class-map, and almost all of
them will have only 1 or 2 class-maps, so theres only a couple dozen
pointers to save.  TODO: re-evaluate for lines removable.

Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
---
v6
. fix compile err due to reorderd commits, and missed lkp report.
. init dt->maps in ddebug_add_module, prior to ddebug_attach_module_classes
---
 lib/dynamic_debug.c | 32 +++++++++++++++++++++++++++++++-
 1 file changed, 31 insertions(+), 1 deletion(-)

diff --git a/lib/dynamic_debug.c b/lib/dynamic_debug.c
index fb31a1a2fc3f..b71efd0b491d 100644
--- a/lib/dynamic_debug.c
+++ b/lib/dynamic_debug.c
@@ -45,7 +45,7 @@ extern struct ddebug_class_map __start___dyndbg_classes[];
 extern struct ddebug_class_map __stop___dyndbg_classes[];
 
 struct ddebug_table {
-	struct list_head link;
+	struct list_head link, maps;
 	const char *mod_name;
 	unsigned int num_ddebugs;
 	struct _ddebug *ddebugs;
@@ -921,6 +921,32 @@ 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)
+{
+	struct ddebug_class_map *cm;
+	int i, j, ct = 0;
+
+	for (cm = classes, i = 0; i < 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 (ct)
+		vpr_info("module:%s attached %d classes\n", dt->mod_name, ct);
+}
+
 /*
  * Allocate a new ddebug_table for the given module
  * and add it to the global list.
@@ -952,6 +978,10 @@ static int __ddebug_add_module(struct _ddebug_info *di, unsigned int base,
 	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);
 
 	mutex_lock(&ddebug_lock);
 	list_add_tail(&dt->link, &ddebug_tables);
-- 
2.37.2

[PATCH v6 17/57] dyndbg: validate class FOO by checking with module

[Jim Cromie]

Add module-to-class validation:

  #> echo class DRM_UT_KMS +p > /proc/dynamic_debug/control

If a query has "class FOO", then ddebug_find_valid_class(), called
from ddebug_change(), requires that FOO is known to module X,
otherwize the query is skipped entirely for X.  This protects each
module's class-space, other than the default:31.

The authors' choice of FOO is highly selective, giving isolation
and/or coordinated sharing of FOOs.  For example, only DRM modules
should know and respond to DRM_UT_KMS.

So this, combined with module's opt-in declaration of known classes,
effectively privatizes the .class_id space for each module (or
coordinated set of modules).

Notes:

For all "class FOO" queries, ddebug_find_valid_class() is called, it
returns the map matching the query, and sets valid_class via an
*outvar).

If no "class FOO" is supplied, valid_class = _CLASS_DFLT.  This
insures that legacy queries do not trample on new class'd callsites,
as they get added.

Also add a new column to control-file output, displaying non-default
class-name (when found) or the "unknown _id:", if it has not been
(correctly) declared with one of the declarator macros.

Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
---
 lib/dynamic_debug.c | 76 ++++++++++++++++++++++++++++++++++++++++-----
 1 file changed, 68 insertions(+), 8 deletions(-)

diff --git a/lib/dynamic_debug.c b/lib/dynamic_debug.c
index b71efd0b491d..db96ded78c3f 100644
--- a/lib/dynamic_debug.c
+++ b/lib/dynamic_debug.c
@@ -56,6 +56,7 @@ struct ddebug_query {
 	const char *module;
 	const char *function;
 	const char *format;
+	const char *class_string;
 	unsigned int first_lineno, last_lineno;
 };
 
@@ -136,15 +137,33 @@ static void vpr_info_dq(const struct ddebug_query *query, const char *msg)
 			fmtlen--;
 	}
 
-	v3pr_info("%s: func=\"%s\" file=\"%s\" module=\"%s\" format=\"%.*s\" lineno=%u-%u\n",
-		 msg,
-		 query->function ?: "",
-		 query->filename ?: "",
-		 query->module ?: "",
-		 fmtlen, query->format ?: "",
-		 query->first_lineno, query->last_lineno);
+	v3pr_info("%s: func=\"%s\" file=\"%s\" module=\"%s\" format=\"%.*s\" lineno=%u-%u class=%s\n",
+		  msg,
+		  query->function ?: "",
+		  query->filename ?: "",
+		  query->module ?: "",
+		  fmtlen, query->format ?: "",
+		  query->first_lineno, query->last_lineno, query->class_string);
 }
 
+static struct ddebug_class_map *ddebug_find_valid_class(struct ddebug_table const *dt,
+							  const char *class_string, int *class_id)
+{
+	struct ddebug_class_map *map;
+	int idx;
+
+	list_for_each_entry(map, &dt->maps, link) {
+		idx = match_string(map->class_names, map->length, class_string);
+		if (idx >= 0) {
+			*class_id = idx + map->base;
+			return map;
+		}
+	}
+	*class_id = -ENOENT;
+	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
@@ -159,6 +178,8 @@ static int ddebug_change(const struct ddebug_query *query,
 	unsigned int newflags;
 	unsigned int nfound = 0;
 	struct flagsbuf fbuf, nbuf;
+	struct ddebug_class_map *map = NULL;
+	int __outvar valid_class;
 
 	/* search for matching ddebugs */
 	mutex_lock(&ddebug_lock);
@@ -169,9 +190,22 @@ static int ddebug_change(const struct ddebug_query *query,
 		    !match_wildcard(query->module, dt->mod_name))
 			continue;
 
+		if (query->class_string) {
+			map = ddebug_find_valid_class(dt, query->class_string, &valid_class);
+			if (!map)
+				continue;
+		} else {
+			/* constrain query, do not touch class'd callsites */
+			valid_class = _DPRINTK_CLASS_DFLT;
+		}
+
 		for (i = 0; i < dt->num_ddebugs; i++) {
 			struct _ddebug *dp = &dt->ddebugs[i];
 
+			/* match site against query-class */
+			if (dp->class_id != valid_class)
+				continue;
+
 			/* match against the source filename */
 			if (query->filename &&
 			    !match_wildcard(query->filename, dp->filename) &&
@@ -420,6 +454,8 @@ static int ddebug_parse_query(char *words[], int nwords,
 		} else if (!strcmp(keyword, "line")) {
 			if (parse_linerange(query, arg))
 				return -EINVAL;
+		} else if (!strcmp(keyword, "class")) {
+			rc = check_set(&query->class_string, arg, "class");
 		} else {
 			pr_err("unknown keyword \"%s\"\n", keyword);
 			return -EINVAL;
@@ -854,6 +890,20 @@ static void *ddebug_proc_next(struct seq_file *m, void *p, loff_t *pos)
 	return dp;
 }
 
+#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)
+{
+	struct ddebug_class_map *map;
+
+	list_for_each_entry(map, &iter->table->maps, link)
+		if (class_in_range(dp->class_id, map))
+			return map->class_names[dp->class_id - map->base];
+
+	return NULL;
+}
+
 /*
  * Seq_ops show method.  Called several times within a read()
  * call from userspace, with ddebug_lock held.  Formats the
@@ -865,6 +915,7 @@ static int ddebug_proc_show(struct seq_file *m, void *p)
 	struct ddebug_iter *iter = m->private;
 	struct _ddebug *dp = p;
 	struct flagsbuf flags;
+	char const *class;
 
 	if (p == SEQ_START_TOKEN) {
 		seq_puts(m,
@@ -877,7 +928,16 @@ static int ddebug_proc_show(struct seq_file *m, void *p)
 		   iter->table->mod_name, dp->function,
 		   ddebug_describe_flags(dp->flags, &flags));
 	seq_escape_str(m, dp->format, ESCAPE_SPACE, "\t\r\n\"");
-	seq_puts(m, "\"\n");
+	seq_puts(m, "\"");
+
+	if (dp->class_id != _DPRINTK_CLASS_DFLT) {
+		class = ddebug_class_name(iter, dp);
+		if (class)
+			seq_printf(m, " class:%s", class);
+		else
+			seq_printf(m, " class unknown, _id:%d", dp->class_id);
+	}
+	seq_puts(m, "\n");
 
 	return 0;
 }
-- 
2.37.2

[PATCH v6 18/57] doc-dyndbg: describe "class CLASS_NAME" query support

[Jim Cromie]

Add an explanation of the new "class CLASS_NAME" syntax and meaning,
noting that the module determines if CLASS_NAME applies to it.

Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
---
 Documentation/admin-guide/dynamic-debug-howto.rst | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/Documentation/admin-guide/dynamic-debug-howto.rst b/Documentation/admin-guide/dynamic-debug-howto.rst
index a89cfa083155..d8954ab05c7b 100644
--- a/Documentation/admin-guide/dynamic-debug-howto.rst
+++ b/Documentation/admin-guide/dynamic-debug-howto.rst
@@ -35,6 +35,7 @@ Dynamic debug has even more useful features:
    - line number (including ranges of line numbers)
    - module name
    - format string
+   - class name (as known/declared by each module)
 
  * Provides a debugfs control file: ``<debugfs>/dynamic_debug/control``
    which can be read to display the complete list of known debug
@@ -142,6 +143,7 @@ against.  Possible keywords are:::
 		 'file' string |
 		 'module' string |
 		 'format' string |
+		 'class' string |
 		 'line' line-range
 
   line-range ::= lineno |
@@ -203,6 +205,15 @@ format
 	format "nfsd: SETATTR"  // a neater way to match a format with whitespace
 	format 'nfsd: SETATTR'  // yet another way to match a format with whitespace
 
+class
+    The given class_name is validated against each module, which may
+    have declared a list of known class_names.  If the class_name is
+    found for a module, callsite & class matching and adjustment
+    proceeds.  Examples::
+
+	class DRM_UT_KMS	# a DRM.debug category
+	class JUNK		# silent non-match
+
 line
     The given line number or range of line numbers is compared
     against the line number of each ``pr_debug()`` callsite.  A single
-- 
2.37.2

[PATCH v6 19/57] doc-dyndbg: edit dynamic-debug-howto for brevity, audience

[Jim Cromie]

Rework/modernize docs:

 - use /proc/dynamic_debug/control in examples
   its *always* there (when dyndbg is config'd), even when <debugfs> is not.
   drop <debugfs> talk, its a distraction here.

 - alias ddcmd='echo $* > /proc/dynamic_debug/control
   focus on args: declutter, hide boilerplate, make pwd independent.

 - swap sections: Viewing before Controlling. control file as Catalog.

 - focus on use by a system administrator
   add an alias to make examples more readable
   drop grep-101 lessons, admins know this.

 - use init/main.c as 1st example, thread it thru doc where useful.
   everybodys kernel boots, runs these.

 - add *prdbg* api section
   to the bottom of the file, its for developers more than admins.
   move list of api functions there.

 - simplify - drop extra words, phrases, sentences.

 - add "decorator" flags line to unify "prefix", trim fmlt descriptions

CC: linux-doc@vger.kernel.org
Signed-off-by: Jim Cromie <jim.cromie@gmail.com>

---
fixup-doc: trailing colons for block headers, trim fedora numbers. Bagas
---
 .../admin-guide/dynamic-debug-howto.rst       | 235 +++++++++---------
 1 file changed, 117 insertions(+), 118 deletions(-)

diff --git a/Documentation/admin-guide/dynamic-debug-howto.rst b/Documentation/admin-guide/dynamic-debug-howto.rst
index d8954ab05c7b..faa22f77847a 100644
--- a/Documentation/admin-guide/dynamic-debug-howto.rst
+++ b/Documentation/admin-guide/dynamic-debug-howto.rst
@@ -5,30 +5,19 @@ Dynamic debug
 Introduction
 ============
 
-This document describes how to use the dynamic debug (dyndbg) feature.
+Dynamic debug allows you to dynamically enable/disable kernel
+debug-print code to obtain additional kernel information.
 
-Dynamic debug is designed to allow you to dynamically enable/disable
-kernel code to obtain additional kernel information.  Currently, if
-``CONFIG_DYNAMIC_DEBUG`` is set, then all ``pr_debug()``/``dev_dbg()`` and
-``print_hex_dump_debug()``/``print_hex_dump_bytes()`` calls can be dynamically
-enabled per-callsite.
+If ``/proc/dynamic_debug/control`` exists, your kernel has dynamic
+debug.  You'll need root access (sudo su) to use this.
 
-If you do not want to enable dynamic debug globally (i.e. in some embedded
-system), you may set ``CONFIG_DYNAMIC_DEBUG_CORE`` as basic support of dynamic
-debug and add ``ccflags := -DDYNAMIC_DEBUG_MODULE`` into the Makefile of any
-modules which you'd like to dynamically debug later.
+Dynamic debug provides:
 
-If ``CONFIG_DYNAMIC_DEBUG`` is not set, ``print_hex_dump_debug()`` is just
-shortcut for ``print_hex_dump(KERN_DEBUG)``.
+ * a Catalog of all *prdbgs* in your kernel.
+   ``cat /proc/dynamic_debug/control`` to see them.
 
-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 has even more useful features:
-
- * Simple query language allows turning on and off debugging
-   statements by matching any combination of 0 or 1 of:
+ * a Simple query/command language to alter *prdbgs* by selecting on
+   any combination of 0 or 1 of:
 
    - source filename
    - function name
@@ -37,107 +26,88 @@ Dynamic debug has even more useful features:
    - format string
    - class name (as known/declared by each module)
 
- * Provides a debugfs control file: ``<debugfs>/dynamic_debug/control``
-   which can be read to display the complete list of known debug
-   statements, to help guide you
-
-Controlling dynamic debug Behaviour
-===================================
-
-The behaviour of ``pr_debug()``/``dev_dbg()`` are controlled via writing to a
-control file in the 'debugfs' filesystem. Thus, you must first mount
-the debugfs filesystem, in order to make use of this feature.
-Subsequently, we refer to the control file as:
-``<debugfs>/dynamic_debug/control``. For example, if you want to enable
-printing from source file ``svcsock.c``, line 1603 you simply do::
-
-  nullarbor:~ # echo 'file svcsock.c line 1603 +p' >
-				<debugfs>/dynamic_debug/control
-
-If you make a mistake with the syntax, the write will fail thus::
-
-  nullarbor:~ # echo 'file svcsock.c wtf 1 +p' >
-				<debugfs>/dynamic_debug/control
-  -bash: echo: write error: Invalid argument
-
-Note, for systems without 'debugfs' enabled, the control file can be
-found in ``/proc/dynamic_debug/control``.
-
 Viewing Dynamic Debug Behaviour
 ===============================
 
-You can view the currently configured behaviour of all the debug
-statements via::
+You can view the currently configured behaviour in the *prdbg* catalog::
 
-  nullarbor:~ # cat <debugfs>/dynamic_debug/control
+  :#> head -n7 /proc/dynamic_debug/control
   # filename:lineno [module]function flags format
-  net/sunrpc/svc_rdma.c:323 [svcxprt_rdma]svc_rdma_cleanup =_ "SVCRDMA Module Removed, deregister RPC RDMA transport\012"
-  net/sunrpc/svc_rdma.c:341 [svcxprt_rdma]svc_rdma_init =_ "\011max_inline       : %d\012"
-  net/sunrpc/svc_rdma.c:340 [svcxprt_rdma]svc_rdma_init =_ "\011sq_depth         : %d\012"
-  net/sunrpc/svc_rdma.c:338 [svcxprt_rdma]svc_rdma_init =_ "\011max_requests     : %d\012"
-  ...
+  init/main.c:1179 [main]initcall_blacklist =_ "blacklisting initcall %s\012
+  init/main.c:1218 [main]initcall_blacklisted =_ "initcall %s blacklisted\012"
+  init/main.c:1424 [main]run_init_process =_ "  with arguments:\012"
+  init/main.c:1426 [main]run_init_process =_ "    %s\012"
+  init/main.c:1427 [main]run_init_process =_ "  with environment:\012"
+  init/main.c:1429 [main]run_init_process =_ "    %s\012"
 
+The 3rd space-delimited column shows the current flags, preceded by
+a ``=`` for easy use with grep/cut. ``=p`` shows enabled callsites.
 
-You can also apply standard Unix text manipulation filters to this
-data, e.g.::
+Controlling dynamic debug Behaviour
+===================================
 
-  nullarbor:~ # grep -i rdma <debugfs>/dynamic_debug/control  | wc -l
-  62
+The behaviour of *prdbg* sites are controlled by writing
+query/commands to the control file.  Example::
 
-  nullarbor:~ # grep -i tcp <debugfs>/dynamic_debug/control | wc -l
-  42
+  # grease the interface
+  :#> alias ddcmd='echo $* > /proc/dynamic_debug/control'
 
-The third column shows the currently enabled flags for each debug
-statement callsite (see below for definitions of the flags).  The
-default value, with no flags enabled, is ``=_``.  So you can view all
-the debug statement callsites with any non-default flags::
+  :#> ddcmd '-p; module main func run* +p'
+  :#> grep =p /proc/dynamic_debug/control
+  init/main.c:1424 [main]run_init_process =p "  with arguments:\012"
+  init/main.c:1426 [main]run_init_process =p "    %s\012"
+  init/main.c:1427 [main]run_init_process =p "  with environment:\012"
+  init/main.c:1429 [main]run_init_process =p "    %s\012"
 
-  nullarbor:~ # awk '$3 != "=_"' <debugfs>/dynamic_debug/control
-  # filename:lineno [module]function flags format
-  net/sunrpc/svcsock.c:1603 [sunrpc]svc_send p "svc_process: st_sendto returned %d\012"
+Error messages go to console/syslog::
+
+  :#> ddcmd mode foo +p
+  dyndbg: unknown keyword "mode"
+  dyndbg: query parse failed
+  bash: echo: write error: Invalid argument
+
+If debugfs is also enabled and mounted, ``dynamic_debug/control`` is
+also under the mount-dir, typically ``/sys/kernel/debug/``.
 
 Command Language Reference
 ==========================
 
-At the lexical level, a command comprises a sequence of words separated
+At the basic lexical level, a command is a sequence of words separated
 by spaces or tabs.  So these are all equivalent::
 
-  nullarbor:~ # echo -n 'file svcsock.c line 1603 +p' >
-				<debugfs>/dynamic_debug/control
-  nullarbor:~ # echo -n '  file   svcsock.c     line  1603 +p  ' >
-				<debugfs>/dynamic_debug/control
-  nullarbor:~ # echo -n 'file svcsock.c line 1603 +p' >
-				<debugfs>/dynamic_debug/control
+  :#> ddcmd file svcsock.c line 1603 +p
+  :#> ddcmd "file svcsock.c line 1603 +p"
+  :#> ddcmd '  file   svcsock.c     line  1603 +p  '
 
 Command submissions are bounded by a write() system call.
 Multiple commands can be written together, separated by ``;`` or ``\n``::
 
-  ~# echo "func pnpacpi_get_resources +p; func pnp_assign_mem +p" \
-     > <debugfs>/dynamic_debug/control
-
-If your query set is big, you can batch them too::
-
-  ~# cat query-batch-file > <debugfs>/dynamic_debug/control
+  :#> ddcmd "func pnpacpi_get_resources +p; func pnp_assign_mem +p"
+  :#> ddcmd <<"EOC"
+  func pnpacpi_get_resources +p
+  func pnp_assign_mem +p
+  EOC
+  :#> cat query-batch-file > /proc/dynamic_debug/control
 
-Another way is to use wildcards. The match rule supports ``*`` (matches
-zero or more characters) and ``?`` (matches exactly one character). For
-example, you can match all usb drivers::
+You can also use wildcards in each query term. The match rule supports
+``*`` (matches zero or more characters) and ``?`` (matches exactly one
+character). For example, you can match all usb drivers::
 
-  ~# echo "file drivers/usb/* +p" > <debugfs>/dynamic_debug/control
+  :#> ddcmd file "drivers/usb/*" +p	# "" to suppress shell expansion
 
-At the syntactical level, a command comprises a sequence of match
-specifications, followed by a flags change specification::
+Syntactically, a command is pairs of keyword values, followed by a
+flags change or setting::
 
   command ::= match-spec* flags-spec
 
-The match-spec's are used to choose a subset of the known pr_debug()
-callsites to which to apply the flags-spec.  Think of them as a query
-with implicit ANDs between each pair.  Note that an empty list of
-match-specs will select all debug statement callsites.
+The match-spec's select *prdbgs* from the catalog, upon which to apply
+the flags-spec, all constraints are ANDed together.  An absent keyword
+is the same as keyword "*".
 
-A match specification comprises a keyword, which controls the
-attribute of the callsite to be compared, and a value to compare
-against.  Possible keywords are:::
+
+A match specification is a keyword, which selects the attribute of
+the callsite to be compared, and a value to compare against.  Possible
+keywords are:::
 
   match-spec ::= 'func' string |
 		 'file' string |
@@ -213,6 +183,7 @@ class
 
 	class DRM_UT_KMS	# a DRM.debug category
 	class JUNK		# silent non-match
+	// class TLD_*		# NOTICE: no wildcard in class names
 
 line
     The given line number or range of line numbers is compared
@@ -239,17 +210,16 @@ of the characters::
 The flags are::
 
   p    enables the pr_debug() callsite.
-  f    Include the function name in the printed message
-  l    Include line number in the printed message
-  m    Include module name in the printed message
-  t    Include thread ID in messages not generated from interrupt context
-  _    No flags are set. (Or'd with others on input)
+  _    enables no flags.
 
-For ``print_hex_dump_debug()`` and ``print_hex_dump_bytes()``, only ``p`` flag
-have meaning, other flags ignored.
+  Decorator flags add to the message-prefix, in order:
+  t    Include thread ID, or <intr>
+  m    Include module name
+  f    Include the function name
+  l    Include line number
 
-For display, the flags are preceded by ``=``
-(mnemonic: what the flags are currently equal to).
+For ``print_hex_dump_debug()`` and ``print_hex_dump_bytes()``, only
+the ``p`` flag has meaning, other flags are ignored.
 
 Note the regexp ``^[-+=][flmpt_]+$`` matches a flags specification.
 To clear all flags at once, use ``=_`` or ``-flmpt``.
@@ -324,7 +294,7 @@ For ``CONFIG_DYNAMIC_DEBUG`` kernels, any settings given at boot-time (or
 enabled by ``-DDEBUG`` flag during compilation) can be disabled later via
 the debugfs interface if the debug messages are no longer needed::
 
-   echo "module module_name -p" > <debugfs>/dynamic_debug/control
+   echo "module module_name -p" > /proc/dynamic_debug/control
 
 Examples
 ========
@@ -332,37 +302,31 @@ Examples
 ::
 
   // enable the message at line 1603 of file svcsock.c
-  nullarbor:~ # echo -n 'file svcsock.c line 1603 +p' >
-				<debugfs>/dynamic_debug/control
+  :#> ddcmd 'file svcsock.c line 1603 +p'
 
   // enable all the messages in file svcsock.c
-  nullarbor:~ # echo -n 'file svcsock.c +p' >
-				<debugfs>/dynamic_debug/control
+  :#> ddcmd 'file svcsock.c +p'
 
   // enable all the messages in the NFS server module
-  nullarbor:~ # echo -n 'module nfsd +p' >
-				<debugfs>/dynamic_debug/control
+  :#> ddcmd 'module nfsd +p'
 
   // enable all 12 messages in the function svc_process()
-  nullarbor:~ # echo -n 'func svc_process +p' >
-				<debugfs>/dynamic_debug/control
+  :#> ddcmd 'func svc_process +p'
 
   // disable all 12 messages in the function svc_process()
-  nullarbor:~ # echo -n 'func svc_process -p' >
-				<debugfs>/dynamic_debug/control
+  :#> ddcmd 'func svc_process -p'
 
   // enable messages for NFS calls READ, READLINK, READDIR and READDIR+.
-  nullarbor:~ # echo -n 'format "nfsd: READ" +p' >
-				<debugfs>/dynamic_debug/control
+  :#> ddcmd 'format "nfsd: READ" +p'
 
   // enable messages in files of which the paths include string "usb"
-  nullarbor:~ # echo -n 'file *usb* +p' > <debugfs>/dynamic_debug/control
+  :#> ddcmd 'file *usb* +p' > /proc/dynamic_debug/control
 
   // enable all messages
-  nullarbor:~ # echo -n '+p' > <debugfs>/dynamic_debug/control
+  :#> ddcmd '+p' > /proc/dynamic_debug/control
 
   // add module, function to all enabled messages
-  nullarbor:~ # echo -n '+mf' > <debugfs>/dynamic_debug/control
+  :#> ddcmd '+mf' > /proc/dynamic_debug/control
 
   // boot-args example, with newlines and comments for readability
   Kernel command line: ...
@@ -375,3 +339,38 @@ Examples
     dyndbg="file init/* +p #cmt ; func parse_one +p"
     // enable pr_debugs in 2 functions in a module loaded later
     pc87360.dyndbg="func pc87360_init_device +p; func pc87360_find +p"
+
+Kernel Configuration
+====================
+
+Dynamic Debug is enabled via kernel config items::
+
+  CONFIG_DYNAMIC_DEBUG=y	# build catalog, enables CORE
+  CONFIG_DYNAMIC_DEBUG_CORE=y	# enable mechanics only, skip catalog
+
+If you do not want to enable dynamic debug globally (i.e. in some embedded
+system), you may set ``CONFIG_DYNAMIC_DEBUG_CORE`` as basic support of dynamic
+debug and add ``ccflags := -DDYNAMIC_DEBUG_MODULE`` into the Makefile of any
+modules which you'd like to dynamically debug later.
+
+
+Kernel *prdbg* API
+==================
+
+The following functions are cataloged and controllable when dynamic
+debug is enabled::
+
+  pr_debug()
+  dev_dbg()
+  print_hex_dump_debug()
+  print_hex_dump_bytes()
+
+Otherwise, they are off by default; ``ccflags += -DDEBUG`` or
+``#define DEBUG`` in a source file will enable them appropriately.
+
+If ``CONFIG_DYNAMIC_DEBUG`` is not set, ``print_hex_dump_debug()`` is
+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.
-- 
2.37.2

[PATCH v6 20/57] dyndbg: add drm.debug style (drm/parameters/debug) bitmap support

[Jim Cromie]

Add kernel_param_ops and callbacks to use a class-map to validate and
apply input to a sysfs-node, which allows users to control classes
defined in that class-map.  This supports uses like:

  echo 0x3 > /sys/module/drm/parameters/debug

IE add these:

 - int param_set_dyndbg_classes()
 - int param_get_dyndbg_classes()
 - struct kernel_param_ops param_ops_dyndbg_classes

Following the model of kernel/params.c STANDARD_PARAM_DEFS, these are
non-static and exported.  This might be unnecessary here.

get/set use an augmented kernel_param; the arg refs a new struct
ddebug_class_param, which contains:

- A ptr to user's state-store; a union of &ulong for drm.debug, &int
  for nouveau level debug.  By ref'g the client's bit-state _var, code
  coordinates with existing code (like drm_debug_enabled) which uses
  it, so existing/remaining calls can work unchanged.  Changing
  drm.debug to a ulong allows use of BIT() etc.

- FLAGS: dyndbg.flags toggled by changes to bitmap. Usually just "p".

- MAP: a pointer to struct ddebug_classes_map, which maps those
  class-names to .class_ids 0..N that the module is using.  This
  class-map is declared & initialized by DECLARE_DYNDBG_CLASSMAP.

- map-type: 4 enums DD_CLASS_TYPE_* select 2 input forms and 2 meanings.

numeric input:
  DD_CLASS_TYPE_DISJOINT_BITS	integer input, independent bits. ie: drm.debug
  DD_CLASS_TYPE_LEVEL_NUM	integer input, 0..N levels

classnames-list (comma separated) input:
  DD_CLASS_TYPE_DISJOINT_NAMES	each name affects a bit, others preserved
  DD_CLASS_TYPE_LEVEL_NAMES	names have level meanings, like kern_levels.h

_NAMES    - comma-separated classnames (with optional +-)
_NUM      - numeric input, 0-N expected
_BITS     - numeric input, 0x1F bitmap form expected

_DISJOINT - bits are independent
_LEVEL    - (x<y) on bit-pos.

_DISJOINT treats input like a bit-vector (ala drm.debug), and sets
each bit accordingly.  LEVEL is layered on top of this.

_LEVEL treats input like a bit-pos:N, then sets bits(0..N)=1, and
bits(N+1..max)=0.  This applies (bit<N) semantics on top of disjoint
bits.

USAGES:

A potentially typical _DISJOINT_NAMES use:

  echo +DRM_UT_CORE,+DRM_UT_KMS,-DRM_UT_DRIVER,-DRM_UT_ATOMIC \
       > /sys/module/drm/parameters/debug_catnames

A naive _LEVEL_NAMES use, with one class, that sets all in the
class-map according to (x<y):

  : problem seen
  echo +L7 > /sys/module/test_dynamic_debug/parameters/p_level_names
  : problem solved
  echo -L1 > /sys/module/test_dynamic_debug/parameters/p_level_names

Note this artifact:

  : this is same as prev cmd (due to +/-)
  echo L0 > /sys/module/test_dynamic_debug/parameters/p_level_names

  : this is "even-more" off, but same wo __pr_debug_class(L0, "..").
  echo -L0 > /sys/module/test_dynamic_debug/parameters/p_level_names

A stress-test/make-work usage (kid toggling a light switch):

  echo +L7,L0,L7,L0,L7,L0,L7,L0,L7,L0,L7,L0,L7 \
       > /sys/module/test_dynamic_debug/parameters/p_level_names

ddebug_apply_class_bitmap(): inside-fn, works on bitmaps, receives
new-bits, finds diffs vs client-bitvector holding "current" state,
and issues exec_query to commit the adjustment.

param_set_dyndbg_classes(): interface fn, sends _NAMES to
param_set_dyndbg_classnames() and returns, falls thru to handle _BITS,
_NUM internally, and calls ddebug_apply_class_bitmap().  Finishes by
updating state.

param_set_dyndbg_classnames(): handles classnames-list in loop, calls
ddebug_apply_class_bitmap for each, then updates state.

NOTES:

_LEVEL_ is overlay on _DISJOINT_; inputs are converted to a bitmask,
by the callbacks.  IOW this is possible, and possibly confusing:

  echo class V3 +p > control
  echo class V1 -p > control

IMO thats ok, relative verbosity is an interface property.

_LEVEL_NUM maps still need class-names, even though the names are not
usable at the sysfs interface (unlike with _NAMES style).  The names
are the only way to >control the classes.

 - It must have a "V0" name,
   something below "V1" to turn "V1" off.
   __pr_debug_cls(V0,..) is printk, don't do that.

 - "class names" is required at the >control interface.
 - relative levels are not enforced at >control

_LEVEL_NAMES bear +/- signs, which alters the on-bit-pos by 1.  IOW,
+L2 means L0,L1,L2, and -L2 means just L0,L1.  This kinda spoils the
readback fidelity, since the L0 bit gets turned on by any use of any
L*, except "-L0".

All the interface uncertainty here pertains to the _NAMES features.
Nobody has actually asked for this, so its practical (if a little
tedious) to split it out.

Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
---
. drop kp->mod->name as unneeded (build-dependent) <lkp>
. param_set_dyndbg_classnames, not _class_strings
. DD_CLASS_TYPE_* name changes, per Jason
. callbacks:
  extend comments on DD_CLASS_TYPE_* handling, flow notes
  varname changes
. kdoc tweaks
. add stub macro: #define KP_NAME(kp)	kp->name
  later, add "$module." prefix when config doesn't do it
. s/struct ddebug_classes_bitmap_param/struct ddebug_class_param/
. fix levels state handling

v4 had trouble where level-type's state was fouled by conversion to
bitmap form given to apply-bitmap.  fix by:

   (simplify/clarify)
   add old-bits, new-bits to sysfs-iface&support
   use CLASSMAP_BITMASK more
   in param_set_dyndbg_class{es,names}():
      move state-saving inside switches, and tailor it to type.
      this preserves lvl-state, vs -v4 which didnt.

I could "hack" in an offset, but the problem feels deeper.

The root-problem may be the ambiguity wrt 0x0 > knob; per a
input-is-assert-bitpos interpretation, it turns on bit 0.

Thus far, code has avoided this ambiguity, by recommending against
coding pr_dbg_cls(V0|L0, ""), which makes "+L0" & "-L0" equivalent,
and "0" silent.

That might be "too clever by 1/2"; accepting an int, so -1 means
all-bits-off as well as verbosity-off, might be the better way.

fix-lvl-sz
---
 include/linux/dynamic_debug.h |  21 ++++
 lib/dynamic_debug.c           | 212 ++++++++++++++++++++++++++++++++++
 2 files changed, 233 insertions(+)

diff --git a/include/linux/dynamic_debug.h b/include/linux/dynamic_debug.h
index 9073a43a2039..41682278d2e8 100644
--- a/include/linux/dynamic_debug.h
+++ b/include/linux/dynamic_debug.h
@@ -119,6 +119,15 @@ struct _ddebug_info {
 	unsigned int num_classes;
 };
 
+struct ddebug_class_param {
+	union {
+		unsigned long *bits;
+		unsigned int *lvl;
+	};
+	char flags[8];
+	const struct ddebug_class_map *map;
+};
+
 #if defined(CONFIG_DYNAMIC_DEBUG_CORE)
 
 int ddebug_add_module(struct _ddebug_info *dyndbg, const char *modname);
@@ -278,6 +287,10 @@ void __dynamic_ibdev_dbg(struct _ddebug *descriptor,
 				   KERN_DEBUG, prefix_str, prefix_type,	\
 				   rowsize, groupsize, buf, len, ascii)
 
+struct kernel_param;
+int param_set_dyndbg_classes(const char *instr, const struct kernel_param *kp);
+int param_get_dyndbg_classes(char *buffer, const struct kernel_param *kp);
+
 /* for test only, generally expect drm.debug style macro wrappers */
 #define __pr_debug_cls(cls, fmt, ...) do {			\
 	BUILD_BUG_ON_MSG(!__builtin_constant_p(cls),		\
@@ -324,6 +337,14 @@ static inline int ddebug_dyndbg_module_param_cb(char *param, char *val,
 				rowsize, groupsize, buf, len, ascii);	\
 	} while (0)
 
+struct kernel_param;
+static inline int param_set_dyndbg_classes(const char *instr, const struct kernel_param *kp)
+{ return 0; }
+static inline int param_get_dyndbg_classes(char *buffer, const struct kernel_param *kp)
+{ return 0; }
+
 #endif /* !CONFIG_DYNAMIC_DEBUG_CORE */
 
+extern const struct kernel_param_ops param_ops_dyndbg_classes;
+
 #endif
diff --git a/lib/dynamic_debug.c b/lib/dynamic_debug.c
index db96ded78c3f..009f2ead09c1 100644
--- a/lib/dynamic_debug.c
+++ b/lib/dynamic_debug.c
@@ -596,6 +596,218 @@ static int ddebug_exec_queries(char *query, const char *modname)
 	return nfound;
 }
 
+/* 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)
+{
+#define QUERY_SIZE 128
+	char query[QUERY_SIZE];
+	const struct ddebug_class_map *map = dcp->map;
+	int matches = 0;
+	int bi, ct;
+
+	v2pr_info("apply: 0x%lx to: 0x%lx\n", *new_bits, *old_bits);
+
+	for (bi = 0; bi < map->length; bi++) {
+		if (test_bit(bi, new_bits) == test_bit(bi, old_bits))
+			continue;
+
+		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);
+		matches += ct;
+
+		v2pr_info("bit_%d: %d matches on class: %s -> 0x%lx\n", bi,
+			  ct, map->class_names[bi], *new_bits);
+	}
+	return matches;
+}
+
+/* stub to later conditionally add "$module." prefix where not already done */
+#define KP_NAME(kp)	kp->name
+
+#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);
+			*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);
+			*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;
+}
+
+/**
+ * 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)
+{
+	const struct ddebug_class_param *dcp = kp->arg;
+	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);
+		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 */
+		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:%lx > %s\n", inrep, KP_NAME(kp));
+		totct += ddebug_apply_class_bitmap(dcp, &inrep, dcp->bits);
+		*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));
+		totct += ddebug_apply_class_bitmap(dcp, &new_bits, &old_bits);
+		*dcp->lvl = inrep;
+		break;
+	default:
+		pr_warn("%s: bad map type: %d\n", KP_NAME(kp), map->map_type);
+	}
+	vpr_info("%s: total matches: %d\n", KP_NAME(kp), totct);
+	return 0;
+}
+EXPORT_SYMBOL(param_set_dyndbg_classes);
+
+/**
+ * param_get_dyndbg_classes - classes reader
+ * @buffer: string description of controlled bits -> classes
+ * @kp:     kp->arg has state: bits, map
+ *
+ * Reads last written state, underlying prdbg state may have been
+ * altered by direct >control.  Displays 0x for DISJOINT, 0-N for
+ * LEVEL Returns: #chars written or <0 on error
+ */
+int param_get_dyndbg_classes(char *buffer, 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_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, "%d\n", *dcp->lvl);
+	default:
+		return -1;
+	}
+}
+EXPORT_SYMBOL(param_get_dyndbg_classes);
+
+const struct kernel_param_ops param_ops_dyndbg_classes = {
+	.set = param_set_dyndbg_classes,
+	.get = param_get_dyndbg_classes,
+};
+EXPORT_SYMBOL(param_ops_dyndbg_classes);
+
 #define PREFIX_SIZE 64
 
 static int remaining(int wrote)
-- 
2.37.2

[PATCH v6 21/57] dyndbg: test DECLARE_DYNDBG_CLASSMAP, sysfs nodes

[Jim Cromie]

Demonstrate use of DECLARE_DYNDBG_CLASSMAP macro, and expose them as
sysfs-nodes for testing.

For each of the 4 class-map-types:

  - declare a class-map of that type,
  - declare the enum corresponding to those class-names
  - share _base across 0..30 range
  - add a __pr_debug_cls() call for each class-name
  - declare 2 sysnodes for each class-map
    for 'p' flag, and future 'T' flag

These declarations create the following sysfs parameter interface:

  :#> pwd
  /sys/module/test_dynamic_debug/parameters
  :#> ls
  T_disjoint_bits  T_disjoint_names  T_level_names  T_level_num  do_prints
  p_disjoint_bits  p_disjoint_names  p_level_names  p_level_num

NOTES:

The local wrapper macro is an api candidate, but there are already too
many parameters.  OTOH, maybe related enum should be in there too,
since it has _base inter-dependencies.

The T_* params control the (future) T flag on the same class'd
pr_debug callsites as their p* counterparts.  Using them will fail,
until the dyndbg-trace patches are added in.

:#> echo 1 > T_disjoint
[   28.792489] dyndbg: disjoint: 0x1 > test_dynamic_debug.T_D2
[   28.793848] dyndbg: query 0: "class D2_CORE +T" mod:*
[   28.795086] dyndbg: split into words: "class" "D2_CORE" "+T"
[   28.796467] dyndbg: op='+'
[   28.797148] dyndbg: unknown flag 'T'
[   28.798021] dyndbg: flags parse failed
[   28.798947] dyndbg: processed 1 queries, with 0 matches, 1 errs
[   28.800378] dyndbg: bit_0: -22 matches on class: D2_CORE -> 0x1
[   28.801959] dyndbg: test_dynamic_debug.T_D2: updated 0x0 -> 0x1
[   28.803974] dyndbg: total matches: -22

Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
---
 lib/test_dynamic_debug.c | 125 ++++++++++++++++++++++++++++++++++-----
 1 file changed, 110 insertions(+), 15 deletions(-)

diff --git a/lib/test_dynamic_debug.c b/lib/test_dynamic_debug.c
index ba3882ca3e48..8dd250ad022b 100644
--- a/lib/test_dynamic_debug.c
+++ b/lib/test_dynamic_debug.c
@@ -10,57 +10,152 @@
 
 #include <linux/module.h>
 
-static void do_prints(void); /* device under test */
-
-/* run tests by reading or writing sysfs node */
+/* run tests 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)
 {
 	do_prints();
 	return 0;
 }
-
 static int param_get_do_prints(char *buffer, const struct kernel_param *kp)
 {
 	do_prints();
 	return scnprintf(buffer, PAGE_SIZE, "did do_prints\n");
 }
-
 static const struct kernel_param_ops param_ops_do_prints = {
 	.set = param_set_do_prints,
 	.get = param_get_do_prints,
 };
-
 module_param_cb(do_prints, &param_ops_do_prints, NULL, 0600);
 
-static void do_alpha(void)
+/*
+ * 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 = {		\
+		.bits = &bits_##_model,					\
+		.flags = #_flags,					\
+		.map = &map_##_model,					\
+	};								\
+	module_param_cb(_flags##_##_model, &param_ops_dyndbg_classes, &_flags##_model, 0600)
+
+/* numeric input, independent bits */
+enum cat_disjoint_bits {
+	D2_CORE = 0,
+	D2_DRIVER,
+	D2_KMS,
+	D2_PRIME,
+	D2_ATOMIC,
+	D2_VBL,
+	D2_STATE,
+	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 = 11, 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 */
+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);
+
+/* stand-in for all pr_debug etc */
+#define prdbg(SYM) __pr_debug_cls(SYM, #SYM " msg\n")
+
+static void do_cats(void)
 {
-	pr_debug("do alpha\n");
+	pr_debug("doing categories\n");
+
+	prdbg(LOW);
+	prdbg(MID);
+	prdbg(HI);
+
+	prdbg(D2_CORE);
+	prdbg(D2_DRIVER);
+	prdbg(D2_KMS);
+	prdbg(D2_PRIME);
+	prdbg(D2_ATOMIC);
+	prdbg(D2_VBL);
+	prdbg(D2_STATE);
+	prdbg(D2_LEASE);
+	prdbg(D2_DP);
+	prdbg(D2_DRMRES);
 }
-static void do_beta(void)
+
+static void do_levels(void)
 {
-	pr_debug("do beta\n");
+	pr_debug("doing levels\n");
+
+	prdbg(V1);
+	prdbg(V2);
+	prdbg(V3);
+	prdbg(V4);
+	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)
 {
-	do_alpha();
-	do_beta();
+	do_cats();
+	do_levels();
 }
 
 static int __init test_dynamic_debug_init(void)
 {
 	pr_debug("init start\n");
-
 	do_prints();
-
 	pr_debug("init done\n");
 	return 0;
 }
 
 static void __exit test_dynamic_debug_exit(void)
 {
-	pr_debug("exiting\n");
+	pr_debug("exited\n");
 }
 
 module_init(test_dynamic_debug_init);
-- 
2.37.2

[PATCH v6 22/57] drm_print: condense enum drm_debug_category

[Jim Cromie]

enum drm_debug_category has 10 categories, but is initialized with
bitmasks which require 10 bits of underlying storage.  By using
natural enumeration, and moving the BIT(cat) into drm_debug_enabled(),
the enum fits in 4 bits, allowing the category to be represented
directly in pr_debug callsites, via the ddebug.class_id field.

While this slightly pessimizes the bit-test in drm_debug_enabled(),
using dyndbg with JUMP_LABEL will avoid the function entirely.

NOTE: this change forecloses the possibility of doing:

  drm_dbg(DRM_UT_CORE|DRM_UT_KMS, "weird 2-cat experiment")

but thats already strongly implied by the use of the enum itself; its
not a normal enum if it can be 2 values simultaneously.

Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
---
 include/drm/drm_print.h | 22 +++++++++++-----------
 1 file changed, 11 insertions(+), 11 deletions(-)

diff --git a/include/drm/drm_print.h b/include/drm/drm_print.h
index 22fabdeed297..b3b470440e46 100644
--- a/include/drm/drm_print.h
+++ b/include/drm/drm_print.h
@@ -279,49 +279,49 @@ enum drm_debug_category {
 	 * @DRM_UT_CORE: Used in the generic drm code: drm_ioctl.c, drm_mm.c,
 	 * drm_memory.c, ...
 	 */
-	DRM_UT_CORE		= 0x01,
+	DRM_UT_CORE,
 	/**
 	 * @DRM_UT_DRIVER: Used in the vendor specific part of the driver: i915,
 	 * radeon, ... macro.
 	 */
-	DRM_UT_DRIVER		= 0x02,
+	DRM_UT_DRIVER,
 	/**
 	 * @DRM_UT_KMS: Used in the modesetting code.
 	 */
-	DRM_UT_KMS		= 0x04,
+	DRM_UT_KMS,
 	/**
 	 * @DRM_UT_PRIME: Used in the prime code.
 	 */
-	DRM_UT_PRIME		= 0x08,
+	DRM_UT_PRIME,
 	/**
 	 * @DRM_UT_ATOMIC: Used in the atomic code.
 	 */
-	DRM_UT_ATOMIC		= 0x10,
+	DRM_UT_ATOMIC,
 	/**
 	 * @DRM_UT_VBL: Used for verbose debug message in the vblank code.
 	 */
-	DRM_UT_VBL		= 0x20,
+	DRM_UT_VBL,
 	/**
 	 * @DRM_UT_STATE: Used for verbose atomic state debugging.
 	 */
-	DRM_UT_STATE		= 0x40,
+	DRM_UT_STATE,
 	/**
 	 * @DRM_UT_LEASE: Used in the lease code.
 	 */
-	DRM_UT_LEASE		= 0x80,
+	DRM_UT_LEASE,
 	/**
 	 * @DRM_UT_DP: Used in the DP code.
 	 */
-	DRM_UT_DP		= 0x100,
+	DRM_UT_DP,
 	/**
 	 * @DRM_UT_DRMRES: Used in the drm managed resources code.
 	 */
-	DRM_UT_DRMRES		= 0x200,
+	DRM_UT_DRMRES
 };
 
 static inline bool drm_debug_enabled(enum drm_debug_category category)
 {
-	return unlikely(__drm_debug & category);
+	return unlikely(__drm_debug & BIT(category));
 }
 
 /*
-- 
2.37.2

[PATCH v6 23/57] drm: POC drm on dyndbg - use in core, 2 helpers, 3 drivers.

[Jim Cromie]

Use DECLARE_DYNDBG_CLASSMAP across DRM:

 - in .c files, since macro defines/initializes a record

 - in drivers, $mod_{drv,drm,param}.c
   ie where param setup is done, since a classmap is param related

 - in drm/drm_print.c
   since existing __drm_debug param is defined there,
   and we ifdef it, and provide an elaborated alternative.

 - in drm_*_helper modules:
   dp/drm_dp - 1st item in makefile target
   drivers/gpu/drm/drm_crtc_helper.c - random pick iirc.

Since these modules all use identical CLASSMAP declarations (ie: names
and .class_id's) they will all respond together to "class DRM_UT_*"
query-commands:

  :#> echo class DRM_UT_KMS +p > /proc/dynamic_debug/control

NOTES:

This changes __drm_debug from int to ulong, so BIT() is usable on it.

DRM's enum drm_debug_category values need to sync with the index of
their respective class-names here.  Then .class_id == category, and
dyndbg's class FOO mechanisms will enable drm_dbg(DRM_UT_KMS, ...).

Though DRM needs consistent categories across all modules, thats not
generally needed; modules X and Y could define FOO differently (ie a
different NAME => class_id mapping), changes are made according to
each module's private class-map.

No callsites are actually selected by this patch, since none are
class'd yet.

Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
---
 drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c | 14 +++++++++++++
 drivers/gpu/drm/display/drm_dp_helper.c | 13 ++++++++++++
 drivers/gpu/drm/drm_crtc_helper.c       | 13 ++++++++++++
 drivers/gpu/drm/drm_print.c             | 27 +++++++++++++++++++++++--
 drivers/gpu/drm/i915/i915_params.c      | 12 +++++++++++
 drivers/gpu/drm/nouveau/nouveau_drm.c   | 13 ++++++++++++
 include/drm/drm_print.h                 |  3 ++-
 7 files changed, 92 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c
index de7144b06e93..97e184f44a52 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c
@@ -38,6 +38,8 @@
 #include <linux/mmu_notifier.h>
 #include <linux/suspend.h>
 #include <linux/cc_platform.h>
+#include <linux/fb.h>
+#include <linux/dynamic_debug.h>
 
 #include "amdgpu.h"
 #include "amdgpu_irq.h"
@@ -185,6 +187,18 @@ int amdgpu_vcnfw_log;
 
 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");
+
 struct amdgpu_mgpu_info mgpu_info = {
 	.mutex = __MUTEX_INITIALIZER(mgpu_info.mutex),
 	.delayed_reset_work = __DELAYED_WORK_INITIALIZER(
diff --git a/drivers/gpu/drm/display/drm_dp_helper.c b/drivers/gpu/drm/display/drm_dp_helper.c
index 92990a3d577a..cbb9c4d6d8f2 100644
--- a/drivers/gpu/drm/display/drm_dp_helper.c
+++ b/drivers/gpu/drm/display/drm_dp_helper.c
@@ -30,6 +30,7 @@
 #include <linux/sched.h>
 #include <linux/seq_file.h>
 #include <linux/string_helpers.h>
+#include <linux/dynamic_debug.h>
 
 #include <drm/display/drm_dp_helper.h>
 #include <drm/display/drm_dp_mst_helper.h>
@@ -40,6 +41,18 @@
 
 #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");
+
 struct dp_aux_backlight {
 	struct backlight_device *base;
 	struct drm_dp_aux *aux;
diff --git a/drivers/gpu/drm/drm_crtc_helper.c b/drivers/gpu/drm/drm_crtc_helper.c
index 457448cc60f7..7d86020b5244 100644
--- a/drivers/gpu/drm/drm_crtc_helper.c
+++ b/drivers/gpu/drm/drm_crtc_helper.c
@@ -32,6 +32,7 @@
 #include <linux/export.h>
 #include <linux/kernel.h>
 #include <linux/moduleparam.h>
+#include <linux/dynamic_debug.h>
 
 #include <drm/drm_atomic.h>
 #include <drm/drm_atomic_helper.h>
@@ -50,6 +51,18 @@
 
 #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");
+
 /**
  * DOC: overview
  *
diff --git a/drivers/gpu/drm/drm_print.c b/drivers/gpu/drm/drm_print.c
index f783d4963d4b..ec32df35a3e3 100644
--- a/drivers/gpu/drm/drm_print.c
+++ b/drivers/gpu/drm/drm_print.c
@@ -40,7 +40,7 @@
  * __drm_debug: Enable debug output.
  * Bitmask of DRM_UT_x. See include/drm/drm_print.h for details.
  */
-unsigned int __drm_debug;
+unsigned long __drm_debug;
 EXPORT_SYMBOL(__drm_debug);
 
 MODULE_PARM_DESC(debug, "Enable debug output, where each bit enables a debug category.\n"
@@ -52,7 +52,30 @@ MODULE_PARM_DESC(debug, "Enable debug output, where each bit enables a debug cat
 "\t\tBit 5 (0x20)  will enable VBL messages (vblank code)\n"
 "\t\tBit 7 (0x80)  will enable LEASE messages (leasing code)\n"
 "\t\tBit 8 (0x100) will enable DP messages (displayport code)");
-module_param_named(debug, __drm_debug, int, 0600);
+
+#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");
+
+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);
+#endif
 
 void __drm_puts_coredump(struct drm_printer *p, const char *str)
 {
diff --git a/drivers/gpu/drm/i915/i915_params.c b/drivers/gpu/drm/i915/i915_params.c
index 6fc475a5db61..d1e4d528cb17 100644
--- a/drivers/gpu/drm/i915/i915_params.c
+++ b/drivers/gpu/drm/i915/i915_params.c
@@ -29,6 +29,18 @@
 #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");
+
 #define i915_param_named(name, T, perm, desc) \
 	module_param_named(name, i915_modparams.name, T, perm); \
 	MODULE_PARM_DESC(name, desc)
diff --git a/drivers/gpu/drm/nouveau/nouveau_drm.c b/drivers/gpu/drm/nouveau/nouveau_drm.c
index 561309d447e0..fd99ec0f4257 100644
--- a/drivers/gpu/drm/nouveau/nouveau_drm.c
+++ b/drivers/gpu/drm/nouveau/nouveau_drm.c
@@ -28,6 +28,7 @@
 #include <linux/pm_runtime.h>
 #include <linux/vga_switcheroo.h>
 #include <linux/mmu_notifier.h>
+#include <linux/dynamic_debug.h>
 
 #include <drm/drm_aperture.h>
 #include <drm/drm_crtc_helper.h>
@@ -70,6 +71,18 @@
 #include "nouveau_svm.h"
 #include "nouveau_dmem.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");
+
 MODULE_PARM_DESC(config, "option string to pass to driver core");
 static char *nouveau_config;
 module_param_named(config, nouveau_config, charp, 0400);
diff --git a/include/drm/drm_print.h b/include/drm/drm_print.h
index b3b470440e46..668273e36c2c 100644
--- a/include/drm/drm_print.h
+++ b/include/drm/drm_print.h
@@ -35,7 +35,7 @@
 #include <drm/drm.h>
 
 /* Do *not* use outside of drm_print.[ch]! */
-extern unsigned int __drm_debug;
+extern unsigned long __drm_debug;
 
 /**
  * DOC: print
@@ -275,6 +275,7 @@ static inline struct drm_printer drm_err_printer(const char *prefix)
  *
  */
 enum drm_debug_category {
+	/* These names must match those in DYNAMIC_DEBUG_CLASSBITS */
 	/**
 	 * @DRM_UT_CORE: Used in the generic drm code: drm_ioctl.c, drm_mm.c,
 	 * drm_memory.c, ...
-- 
2.37.2

[PATCH v6 24/57] drm_print: interpose drm_*dbg with forwarding macros

[Jim Cromie]

change drm_dev_dbg & drm_dbg to macros, which forward to the renamed
functions (with __ prefix added).

Those functions sit below the categorized layer of macros implementing
the DRM debug.category API, and implement most of it.  These are good
places to insert dynamic-debug jump-label mechanics, which will allow
DRM to avoid the runtime cost of drm_debug_enabled().

no functional changes.

memory cost baseline: (unchanged)
bash-5.1# drms_load
[    9.220389] dyndbg:   1 debug prints in module drm
[    9.224426] ACPI: bus type drm_connector registered
[    9.302192] dyndbg:   2 debug prints in module ttm
[    9.305033] dyndbg:   8 debug prints in module video
[    9.627563] dyndbg: 127 debug prints in module i915
[    9.721505] AMD-Vi: AMD IOMMUv2 functionality not available on this system - This is not a bug.
[   10.091345] dyndbg: 2196 debug prints in module amdgpu
[   10.106589] [drm] amdgpu kernel modesetting enabled.
[   10.107270] amdgpu: CRAT table not found
[   10.107926] amdgpu: Virtual CRAT table created for CPU
[   10.108398] amdgpu: Topology: Add CPU node
[   10.168507] dyndbg:   3 debug prints in module wmi
[   10.329587] dyndbg:   3 debug prints in module nouveau

Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
---
 drivers/gpu/drm/drm_print.c | 10 +++++-----
 include/drm/drm_print.h     |  9 +++++++--
 2 files changed, 12 insertions(+), 7 deletions(-)

diff --git a/drivers/gpu/drm/drm_print.c b/drivers/gpu/drm/drm_print.c
index ec32df35a3e3..29a29949ad0b 100644
--- a/drivers/gpu/drm/drm_print.c
+++ b/drivers/gpu/drm/drm_print.c
@@ -279,8 +279,8 @@ void drm_dev_printk(const struct device *dev, const char *level,
 }
 EXPORT_SYMBOL(drm_dev_printk);
 
-void drm_dev_dbg(const struct device *dev, enum drm_debug_category category,
-		 const char *format, ...)
+void __drm_dev_dbg(const struct device *dev, enum drm_debug_category category,
+		   const char *format, ...)
 {
 	struct va_format vaf;
 	va_list args;
@@ -301,9 +301,9 @@ void drm_dev_dbg(const struct device *dev, enum drm_debug_category category,
 
 	va_end(args);
 }
-EXPORT_SYMBOL(drm_dev_dbg);
+EXPORT_SYMBOL(__drm_dev_dbg);
 
-void __drm_dbg(enum drm_debug_category category, const char *format, ...)
+void ___drm_dbg(enum drm_debug_category category, const char *format, ...)
 {
 	struct va_format vaf;
 	va_list args;
@@ -320,7 +320,7 @@ void __drm_dbg(enum drm_debug_category category, const char *format, ...)
 
 	va_end(args);
 }
-EXPORT_SYMBOL(__drm_dbg);
+EXPORT_SYMBOL(___drm_dbg);
 
 void __drm_err(const char *format, ...)
 {
diff --git a/include/drm/drm_print.h b/include/drm/drm_print.h
index 668273e36c2c..c429c258c957 100644
--- a/include/drm/drm_print.h
+++ b/include/drm/drm_print.h
@@ -335,7 +335,7 @@ __printf(3, 4)
 void drm_dev_printk(const struct device *dev, const char *level,
 		    const char *format, ...);
 __printf(3, 4)
-void drm_dev_dbg(const struct device *dev, enum drm_debug_category category,
+void __drm_dev_dbg(const struct device *dev, enum drm_debug_category category,
 		 const char *format, ...);
 
 /**
@@ -384,6 +384,9 @@ void drm_dev_dbg(const struct device *dev, enum drm_debug_category category,
 	}								\
 })
 
+#define drm_dev_dbg(dev, cat, fmt, ...)				\
+	__drm_dev_dbg(dev, cat, fmt, ##__VA_ARGS__)
+
 /**
  * DRM_DEV_DEBUG() - Debug output for generic drm code
  *
@@ -485,10 +488,12 @@ void drm_dev_dbg(const struct device *dev, enum drm_debug_category category,
  */
 
 __printf(2, 3)
-void __drm_dbg(enum drm_debug_category category, const char *format, ...);
+void ___drm_dbg(enum drm_debug_category category, const char *format, ...);
 __printf(1, 2)
 void __drm_err(const char *format, ...);
 
+#define __drm_dbg(fmt, ...)		___drm_dbg(fmt, ##__VA_ARGS__)
+
 /* Macros to make printk easier */
 
 #define _DRM_PRINTK(once, level, fmt, ...)				\
-- 
2.37.2

[PATCH v6 25/57] drm_print: wrap drm_*_dbg in dyndbg descriptor factory macro

[Jim Cromie]

For CONFIG_DRM_USE_DYNAMIC_DEBUG=y, wrap __drm_dbg() & __drm_dev_dbg()
in one of dyndbg's Factory macros: _dynamic_func_call_no_desc().

This adds the callsite descriptor into the code, and an entry for each
into /proc/dynamic_debug/control.

  #> echo class DRM_UT_ATOMIC +p > /proc/dynamic_debug/control

CONFIG_DRM_USE_DYNAMIC_DEBUG=y/n is configurable because of the .data
footprint cost of per-callsite control; 56 bytes/site * ~2k for i915,
~4k callsites for amdgpu.  This is large enough that a kernel builder
might not want it.

Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
---
 drivers/gpu/drm/Kconfig  | 12 ++++++++++++
 drivers/gpu/drm/Makefile |  2 ++
 include/drm/drm_print.h  | 12 ++++++++++++
 3 files changed, 26 insertions(+)

diff --git a/drivers/gpu/drm/Kconfig b/drivers/gpu/drm/Kconfig
index 2f52e8941074..3b75c286f14f 100644
--- a/drivers/gpu/drm/Kconfig
+++ b/drivers/gpu/drm/Kconfig
@@ -51,6 +51,18 @@ config DRM_DEBUG_MM
 
 	  If in doubt, say "N".
 
+config DRM_USE_DYNAMIC_DEBUG
+	bool "use dynamic debug to implement drm.debug"
+	default y
+	depends on DRM
+	depends on DYNAMIC_DEBUG || DYNAMIC_DEBUG_CORE
+	depends on JUMP_LABEL
+	help
+	  Use dynamic-debug to avoid drm_debug_enabled() runtime overheads.
+	  Due to callsite counts in DRM drivers (~4k in amdgpu) and 56
+	  bytes per callsite, the .data costs can be substantial, and
+	  are therefore configurable.
+
 config DRM_KUNIT_TEST
 	tristate "KUnit tests for DRM" if !KUNIT_ALL_TESTS
 	depends on DRM && KUNIT
diff --git a/drivers/gpu/drm/Makefile b/drivers/gpu/drm/Makefile
index 25d0ba310509..0b283e46f28b 100644
--- a/drivers/gpu/drm/Makefile
+++ b/drivers/gpu/drm/Makefile
@@ -3,6 +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
+
 drm-y       :=	drm_aperture.o drm_auth.o drm_cache.o \
 		drm_file.o drm_gem.o drm_ioctl.o \
 		drm_drv.o \
diff --git a/include/drm/drm_print.h b/include/drm/drm_print.h
index c429c258c957..2d2cef76b5c1 100644
--- a/include/drm/drm_print.h
+++ b/include/drm/drm_print.h
@@ -384,8 +384,14 @@ void __drm_dev_dbg(const struct device *dev, enum drm_debug_category category,
 	}								\
 })
 
+#if !defined(CONFIG_DRM_USE_DYNAMIC_DEBUG)
 #define drm_dev_dbg(dev, cat, fmt, ...)				\
 	__drm_dev_dbg(dev, cat, fmt, ##__VA_ARGS__)
+#else
+#define drm_dev_dbg(dev, cat, fmt, ...)				\
+	_dynamic_func_call_no_desc(fmt, __drm_dev_dbg,			\
+				   dev, cat, fmt, ##__VA_ARGS__)
+#endif
 
 /**
  * DRM_DEV_DEBUG() - Debug output for generic drm code
@@ -492,7 +498,13 @@ void ___drm_dbg(enum drm_debug_category category, const char *format, ...);
 __printf(1, 2)
 void __drm_err(const char *format, ...);
 
+#if !defined(CONFIG_DRM_USE_DYNAMIC_DEBUG)
 #define __drm_dbg(fmt, ...)		___drm_dbg(fmt, ##__VA_ARGS__)
+#else
+#define __drm_dbg(cat, fmt, ...)					\
+	_dynamic_func_call_no_desc(fmt, ___drm_dbg,			\
+				   cat, fmt, ##__VA_ARGS__)
+#endif
 
 /* Macros to make printk easier */
 
-- 
2.37.2

[PATCH v6 26/57] drm-print.h: include dyndbg header

[Jim Cromie]

lkp robot told me:

  >> drivers/gpu/drm/drm_ioc32.c:989:2:
  error: call to undeclared function '_dynamic_func_call_cls';
  ISO C99 and later do not support implicit function declarations
  [-Wimplicit-function-declaration]

           DRM_DEBUG("comm=\"%s\", pid=%d, dev=0x%lx, auth=%d, %s\n",

Since that macro is defined in drm_print.h, and under DRM_USE_DYN*=y
configs, invokes dyndbg-factory macros, include dynamic_debug.h from
there too, so that those configs have the definitions of all the
macros in the callchain.

This is done as a separate patch mostly to see how lkp sorts it.

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

diff --git a/include/drm/drm_print.h b/include/drm/drm_print.h
index 2d2cef76b5c1..f8bb3e7158c6 100644
--- a/include/drm/drm_print.h
+++ b/include/drm/drm_print.h
@@ -31,6 +31,7 @@
 #include <linux/seq_file.h>
 #include <linux/device.h>
 #include <linux/debugfs.h>
+#include <linux/dynamic_debug.h>
 
 #include <drm/drm.h>
 
-- 
2.37.2

[PATCH v6 27/57] drm-print: add drm_dbg_driver to improve namespace symmetry

[Jim Cromie]

drm_print defines all of these:
    drm_dbg_{core,kms,prime,atomic,vbl,lease,_dp,_drmres}

but not drm_dbg_driver itself, since it was the original drm_dbg.

To improve namespace symmetry, change the drm_dbg defn to
drm_dbg_driver, and redef grandfathered name to symmetric one.

This will help with nouveau, which uses its own stack of macros to
construct calls to dev_info, dev_dbg, etc, for which adaptation means
drm_dbg_##driver constructs.

Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
---
 include/drm/drm_print.h | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/include/drm/drm_print.h b/include/drm/drm_print.h
index f8bb3e7158c6..dfdd81c3287c 100644
--- a/include/drm/drm_print.h
+++ b/include/drm/drm_print.h
@@ -468,7 +468,7 @@ void __drm_dev_dbg(const struct device *dev, enum drm_debug_category category,
 
 #define drm_dbg_core(drm, fmt, ...)					\
 	drm_dev_dbg((drm) ? (drm)->dev : NULL, DRM_UT_CORE, fmt, ##__VA_ARGS__)
-#define drm_dbg(drm, fmt, ...)						\
+#define drm_dbg_driver(drm, fmt, ...)						\
 	drm_dev_dbg((drm) ? (drm)->dev : NULL, DRM_UT_DRIVER, fmt, ##__VA_ARGS__)
 #define drm_dbg_kms(drm, fmt, ...)					\
 	drm_dev_dbg((drm) ? (drm)->dev : NULL, DRM_UT_KMS, fmt, ##__VA_ARGS__)
@@ -487,6 +487,7 @@ void __drm_dev_dbg(const struct device *dev, enum drm_debug_category category,
 #define drm_dbg_drmres(drm, fmt, ...)					\
 	drm_dev_dbg((drm) ? (drm)->dev : NULL, DRM_UT_DRMRES, fmt, ##__VA_ARGS__)
 
+#define drm_dbg(drm, fmt, ...)	drm_dbg_driver(drm, fmt, ##__VA_ARGS__)
 
 /*
  * printk based logging
-- 
2.37.2

[PATCH v6 28/57] drm_print: refine drm_debug_enabled for jump-label

[Jim Cromie]

In order to use dynamic-debug's jump-label optimization in drm-debug,
its clarifying to refine drm_debug_enabled into 3 uses:

1.   drm_debug_enabled - legacy, public
2. __drm_debug_enabled - optimized for dyndbg jump-label enablement.
3.  _drm_debug_enabled - pr_debug instrumented, observable

1. The legacy version always checks the bits.

2. is privileged, for use by __drm_dbg(), __drm_dev_dbg(), which do an
early return unless the category is enabled.  For dyndbg builds, debug
callsites are selectively "pre-enabled", so __drm_debug_enabled()
short-circuits to true there.  Remaining callers of 1 may be able to
use 2, case by case.

3. is 1st wrapped in a macro, with a pr_debug, which reports each
usage in /proc/dynamic_debug/control, making it observable in the
logs.  The macro lets the pr_debug see the real caller, not an inline
function.

When plugged into 1, 3 identified ~10 remaining callers of the
function, leading to the follow-on cleanup patch, and would allow
activating the pr_debugs, estimating the callrate, and the potential
savings by using the wrapper macro.  It is unused ATM, but it fills
out the picture.

Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
---
 drivers/gpu/drm/drm_print.c |  4 ++--
 include/drm/drm_print.h     | 28 ++++++++++++++++++++++++++++
 2 files changed, 30 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/drm_print.c b/drivers/gpu/drm/drm_print.c
index 29a29949ad0b..cb203d63b286 100644
--- a/drivers/gpu/drm/drm_print.c
+++ b/drivers/gpu/drm/drm_print.c
@@ -285,7 +285,7 @@ void __drm_dev_dbg(const struct device *dev, enum drm_debug_category category,
 	struct va_format vaf;
 	va_list args;
 
-	if (!drm_debug_enabled(category))
+	if (!__drm_debug_enabled(category))
 		return;
 
 	va_start(args, format);
@@ -308,7 +308,7 @@ void ___drm_dbg(enum drm_debug_category category, const char *format, ...)
 	struct va_format vaf;
 	va_list args;
 
-	if (!drm_debug_enabled(category))
+	if (!__drm_debug_enabled(category))
 		return;
 
 	va_start(args, format);
diff --git a/include/drm/drm_print.h b/include/drm/drm_print.h
index dfdd81c3287c..7631b5fb669e 100644
--- a/include/drm/drm_print.h
+++ b/include/drm/drm_print.h
@@ -321,11 +321,39 @@ enum drm_debug_category {
 	DRM_UT_DRMRES
 };
 
+/*
+ * 3 name flavors of drm_debug_enabled:
+ *   drm_debug_enabled - public/legacy, always checks bits
+ *  _drm_debug_enabled - instrumented to observe call-rates, est overheads.
+ * __drm_debug_enabled - privileged - knows jump-label state, can short-circuit
+ */
 static inline bool drm_debug_enabled(enum drm_debug_category category)
 {
 	return unlikely(__drm_debug & BIT(category));
 }
 
+/*
+ * Wrap fn in macro, so that the pr_debug sees the actual caller, not
+ * the inline fn.  Using this name creates a callsite entry / control
+ * point in /proc/dynamic_debug/control.
+ */
+#define _drm_debug_enabled(category)				\
+	({							\
+		pr_debug("todo: maybe avoid via dyndbg\n");     \
+		drm_debug_enabled(category);			\
+	})
+
+#if defined(CONFIG_DRM_USE_DYNAMIC_DEBUG)
+/*
+ * dyndbg is wrapping the drm.debug API, so as to avoid the runtime
+ * bit-test overheads of drm_debug_enabled() in those api calls.
+ * In this case, executed callsites are known enabled, so true.
+ */
+#define __drm_debug_enabled(category)	true
+#else
+#define __drm_debug_enabled(category)	drm_debug_enabled(category)
+#endif
+
 /*
  * struct device based logging
  *
-- 
2.37.2

[PATCH v6 29/57] drm_print: prefer bare printk KERN_DEBUG on generic fn

[Jim Cromie]

drm_print.c calls pr_debug() just once, from __drm_printfn_debug(),
which is a generic/service fn.  The callsite is compile-time enabled
by DEBUG in both DYNAMIC_DEBUG=y/n builds.

For dyndbg builds, reverting this callsite back to bare printk is
correcting a few anti-features:

1- callsite is generic, serves multiple drm users.
   it is soft-wired on currently by #define DEBUG
   could accidentally: #> echo -p > /proc/dynamic_debug/control

2- optional "decorations" by dyndbg are unhelpful/misleading here,
   they describe only the generic site, not end users

IOW, 1,2 are unhelpful at best, and possibly confusing.

reverting yields a nominal data and text shrink:

   text    data     bss     dec     hex filename
 462583   36604   54592 553779   87333 /kernel/drivers/gpu/drm/drm.ko
 462515   36532   54592 553639   872a7 -dirty/kernel/drivers/gpu/drm/drm.ko

Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
---
 drivers/gpu/drm/drm_print.c | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/drm_print.c b/drivers/gpu/drm/drm_print.c
index cb203d63b286..ec477c44a784 100644
--- a/drivers/gpu/drm/drm_print.c
+++ b/drivers/gpu/drm/drm_print.c
@@ -23,8 +23,6 @@
  * Rob Clark <robdclark@gmail.com>
  */
 
-#define DEBUG /* for pr_debug() */
-
 #include <linux/stdarg.h>
 
 #include <linux/io.h>
@@ -185,7 +183,8 @@ EXPORT_SYMBOL(__drm_printfn_info);
 
 void __drm_printfn_debug(struct drm_printer *p, struct va_format *vaf)
 {
-	pr_debug("%s %pV", p->prefix, vaf);
+	/* pr_debug callsite decorations are unhelpful here */
+	printk(KERN_DEBUG "%s %pV", p->prefix, vaf);
 }
 EXPORT_SYMBOL(__drm_printfn_debug);
 
-- 
2.37.2

[PATCH v6 30/57] drm_print: add _ddebug descriptor to drm_*dbg prototypes

[Jim Cromie]

upgrade the callchain to drm_dbg() and drm_dev_dbg(); add a struct
_ddebug ptr parameter to them, and supply that additional param by
replacing the '_no_desc' flavor of dyndbg Factory macro currently used
with the flavor that supplies the descriptor.

NOTES:

The descriptor gives these fns access to the decorator flags, but does
none of the dynamic-prefixing done by __dynamic_emit_prefix().

DRM already has conventions for logging/messaging; just tossing
optional decorations on top may not help.  Instead, existing flags (or
new ones) can be used to make current conventions optional.

For CONFIG_DRM_USE_DYNAMIC_DEBUG=N, just pass null.

Note: desc->class_id is redundant with category parameter, but its
availability is dependent on desc.

Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
---
 drivers/gpu/drm/drm_print.c |  8 +++++---
 include/drm/drm_print.h     | 23 ++++++++++++-----------
 2 files changed, 17 insertions(+), 14 deletions(-)

diff --git a/drivers/gpu/drm/drm_print.c b/drivers/gpu/drm/drm_print.c
index ec477c44a784..5b93c11895bb 100644
--- a/drivers/gpu/drm/drm_print.c
+++ b/drivers/gpu/drm/drm_print.c
@@ -29,6 +29,7 @@
 #include <linux/moduleparam.h>
 #include <linux/seq_file.h>
 #include <linux/slab.h>
+#include <linux/dynamic_debug.h>
 
 #include <drm/drm.h>
 #include <drm/drm_drv.h>
@@ -278,8 +279,8 @@ void drm_dev_printk(const struct device *dev, const char *level,
 }
 EXPORT_SYMBOL(drm_dev_printk);
 
-void __drm_dev_dbg(const struct device *dev, enum drm_debug_category category,
-		   const char *format, ...)
+void __drm_dev_dbg(struct _ddebug *desc, const struct device *dev,
+		   enum drm_debug_category category, const char *format, ...)
 {
 	struct va_format vaf;
 	va_list args;
@@ -287,6 +288,7 @@ void __drm_dev_dbg(const struct device *dev, enum drm_debug_category category,
 	if (!__drm_debug_enabled(category))
 		return;
 
+	/* we know we are printing for either syslog, tracefs, or both */
 	va_start(args, format);
 	vaf.fmt = format;
 	vaf.va = &args;
@@ -302,7 +304,7 @@ void __drm_dev_dbg(const struct device *dev, enum drm_debug_category category,
 }
 EXPORT_SYMBOL(__drm_dev_dbg);
 
-void ___drm_dbg(enum drm_debug_category category, const char *format, ...)
+void ___drm_dbg(struct _ddebug *desc, enum drm_debug_category category, const char *format, ...)
 {
 	struct va_format vaf;
 	va_list args;
diff --git a/include/drm/drm_print.h b/include/drm/drm_print.h
index 7631b5fb669e..46f14cfb401e 100644
--- a/include/drm/drm_print.h
+++ b/include/drm/drm_print.h
@@ -363,9 +363,10 @@ static inline bool drm_debug_enabled(enum drm_debug_category category)
 __printf(3, 4)
 void drm_dev_printk(const struct device *dev, const char *level,
 		    const char *format, ...);
-__printf(3, 4)
-void __drm_dev_dbg(const struct device *dev, enum drm_debug_category category,
-		 const char *format, ...);
+struct _ddebug;
+__printf(4, 5)
+void __drm_dev_dbg(struct _ddebug *desc, const struct device *dev,
+		   enum drm_debug_category category, const char *format, ...);
 
 /**
  * DRM_DEV_ERROR() - Error output.
@@ -415,11 +416,11 @@ void __drm_dev_dbg(const struct device *dev, enum drm_debug_category category,
 
 #if !defined(CONFIG_DRM_USE_DYNAMIC_DEBUG)
 #define drm_dev_dbg(dev, cat, fmt, ...)				\
-	__drm_dev_dbg(dev, cat, fmt, ##__VA_ARGS__)
+	__drm_dev_dbg(NULL, dev, cat, fmt, ##__VA_ARGS__)
 #else
 #define drm_dev_dbg(dev, cat, fmt, ...)				\
-	_dynamic_func_call_no_desc(fmt, __drm_dev_dbg,			\
-				   dev, cat, fmt, ##__VA_ARGS__)
+	_dynamic_func_call_cls(cat, fmt, __drm_dev_dbg,		\
+			       dev, cat, fmt, ##__VA_ARGS__)
 #endif
 
 /**
@@ -523,17 +524,17 @@ void __drm_dev_dbg(const struct device *dev, enum drm_debug_category category,
  * Prefer drm_device based logging over device or prink based logging.
  */
 
-__printf(2, 3)
-void ___drm_dbg(enum drm_debug_category category, const char *format, ...);
+__printf(3, 4)
+void ___drm_dbg(struct _ddebug *desc, enum drm_debug_category category, const char *format, ...);
 __printf(1, 2)
 void __drm_err(const char *format, ...);
 
 #if !defined(CONFIG_DRM_USE_DYNAMIC_DEBUG)
-#define __drm_dbg(fmt, ...)		___drm_dbg(fmt, ##__VA_ARGS__)
+#define __drm_dbg(fmt, ...)		___drm_dbg(NULL, fmt, ##__VA_ARGS__)
 #else
 #define __drm_dbg(cat, fmt, ...)					\
-	_dynamic_func_call_no_desc(fmt, ___drm_dbg,			\
-				   cat, fmt, ##__VA_ARGS__)
+	_dynamic_func_call_cls(cat, fmt, ___drm_dbg,			\
+			       cat, fmt, ##__VA_ARGS__)
 #endif
 
 /* Macros to make printk easier */
-- 
2.37.2

[PATCH v6 31/57] nouveau: change nvkm_debug/trace to use dev_dbg POC

[Jim Cromie]

These 2 macros formerly used dev_info, and they still check
subdev->debug to gate the printing.  So dyndbg control is redundant
ATM (and possibly confusing, since its off by default).

prdbg count is up from 3, or from 65 (with VMM_DEBUG here)

[    7.765379] dyndbg: 516 debug prints in module nouveau

Its possible to control error, warn, info callsites too, but they're
usually on, and the .data overheads on ~450 more callsites (56 bytes
each) would just be wasted.

$ for l in fatal error warn info debug trace spam; do
      echo $l; ack nvkm_$l drivers/gpu |wc; done
fatal
      3      19     335
error
    289    1956   30651
warn
     84     513    8860
info
     14      88    1502
debug
    387    2339   40844
trace
     31     219    3368
spam
      1       7     123

bash-5.1# echo $(( 516-65-387-31-1 ))
32

Thats approximate; not accounting #defines and doc/comment mentions.

NOTE: this patch changes the log-level of the macro-issued messages
from KERN_INFO to KERN_DEBUG.  Adding a .kern_lvl field to struct
_ddebug could fix that.

RFC: dyndbg & subdev->debug

Separate class-maps for each subdev are possible; except for the
coordinated use of _base, each is independent, including choice of
DISJOINT or LEVELS, as long as class-names don't conflict.
So theres some flexibility.

Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
---
 drivers/gpu/drm/nouveau/include/nvkm/core/subdev.h | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/nouveau/include/nvkm/core/subdev.h b/drivers/gpu/drm/nouveau/include/nvkm/core/subdev.h
index 96113c8bee8c..065d07ccea87 100644
--- a/drivers/gpu/drm/nouveau/include/nvkm/core/subdev.h
+++ b/drivers/gpu/drm/nouveau/include/nvkm/core/subdev.h
@@ -59,8 +59,8 @@ void nvkm_subdev_intr(struct nvkm_subdev *);
 #define nvkm_error(s,f,a...) nvkm_printk((s), ERROR,    err, f, ##a)
 #define nvkm_warn(s,f,a...)  nvkm_printk((s),  WARN, notice, f, ##a)
 #define nvkm_info(s,f,a...)  nvkm_printk((s),  INFO,   info, f, ##a)
-#define nvkm_debug(s,f,a...) nvkm_printk((s), DEBUG,   info, f, ##a)
-#define nvkm_trace(s,f,a...) nvkm_printk((s), TRACE,   info, f, ##a)
+#define nvkm_debug(s,f,a...) nvkm_printk((s), DEBUG,    dbg, f, ##a)
+#define nvkm_trace(s,f,a...) nvkm_printk((s), TRACE,    dbg, f, ##a)
 #define nvkm_spam(s,f,a...)  nvkm_printk((s),  SPAM,    dbg, f, ##a)
 
 #define nvkm_error_ratelimited(s,f,a...) nvkm_printk((s), ERROR, err_ratelimited, f, ##a)
-- 
2.37.2

[PATCH v6 32/57] nouveau: adapt NV_DEBUG, NV_ATOMIC to use DRM.debug

[Jim Cromie]

These 2 macros used drm_debug_enabled() on DRM_UT_{DRIVER,ATOMIC}
respectively, replace those with drm_dbg_##cat invocations.

this results in new class'd prdbg callsites:

:#> grep nouveau /proc/dynamic_debug/control | grep class | wc
    116    1130   15584
:#> grep nouveau /proc/dynamic_debug/control | grep class | grep DRIVER | wc
     74     704    9709
:#> grep nouveau /proc/dynamic_debug/control | grep class | grep ATOMIC | wc
     31     307    4237
:#> grep nouveau /proc/dynamic_debug/control | grep class | grep KMS | wc
     11     119    1638

the KMS entries are due to existing uses of drm_dbg_kms().

Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
---
 drivers/gpu/drm/nouveau/nouveau_drv.h | 16 ++++++++++------
 1 file changed, 10 insertions(+), 6 deletions(-)

diff --git a/drivers/gpu/drm/nouveau/nouveau_drv.h b/drivers/gpu/drm/nouveau/nouveau_drv.h
index 84df5ddae4d0..3b8a76004b57 100644
--- a/drivers/gpu/drm/nouveau/nouveau_drv.h
+++ b/drivers/gpu/drm/nouveau/nouveau_drv.h
@@ -39,6 +39,7 @@
  */
 
 #include <linux/notifier.h>
+#include <linux/dynamic_debug.h>
 
 #include <nvif/client.h>
 #include <nvif/device.h>
@@ -263,13 +264,16 @@ void nouveau_drm_device_remove(struct drm_device *dev);
 #define NV_WARN(drm,f,a...) NV_PRINTK(warn, &(drm)->client, f, ##a)
 #define NV_INFO(drm,f,a...) NV_PRINTK(info, &(drm)->client, f, ##a)
 
-#define NV_DEBUG(drm,f,a...) do {                                              \
-	if (drm_debug_enabled(DRM_UT_DRIVER))                                  \
-		NV_PRINTK(info, &(drm)->client, f, ##a);                       \
+#define NV_DRMDBG(cat,c,f,a...) do {				\
+	struct nouveau_cli *_cli = (c);				\
+	drm_dbg_##cat(_cli->drm->dev, "%s: "f, _cli->name, ##a); \
 } while(0)
-#define NV_ATOMIC(drm,f,a...) do {                                             \
-	if (drm_debug_enabled(DRM_UT_ATOMIC))                                  \
-		NV_PRINTK(info, &(drm)->client, f, ##a);                       \
+
+#define NV_DEBUG(drm,f,a...) do {					\
+	NV_DRMDBG(driver, &(drm)->client, f, ##a);			\
+} while(0)
+#define NV_ATOMIC(drm,f,a...) do {					\
+	NV_DRMDBG(atomic, &(drm)->client, f, ##a);			\
 } while(0)
 
 #define NV_PRINTK_ONCE(l,c,f,a...) NV_PRINTK(l##_once,c,f, ##a)
-- 
2.37.2

[PATCH v6 33/57] nouveau: WIP add 2 LEVEL_NUM classmaps for CLI, SUBDEV

[Jim Cromie]

clone the nvkm_printk,_,__ macro ladder into nvkm_drmdbg,_,__.
And alter the debug, trace, spam macros to use the renamed ladder.

This *sets-up* (not done yet) to remove the _subdev->debug >= (l)
condition, once the bitmap-param is wired up correctly, and figured
into dyndbg's jump-label enablement.  WIP.

Then undo the 1-line change that reduced count of prdbgs from 632 to 119.

ie: s/NV_SUBDEV_DBG_##l/NV_DBG_##l/

So heres what happened: new symbol is 15 (or 10), and fails this macro
test, so gets compiled out, and the dev_dbg is excluded.

        if (CONFIG_NOUVEAU_DEBUG >= (l) && _subdev->debug >= (l))       \
                dev_dbg(_subdev->device->dev, "%s: "f, _subdev->name, ##a); \

I could hack this, by doing (l + base), but base is pretty distant.

OTOH, the whole CONFIG_NOUVEAU_DEBUG check could be reworked; given
that trace is minumum recommended, theres not that many callsites
elided (SPAM only iirc) at compile-time, and dyndbg means keeping them
has "zero" run-cost (and 56 bytes per callsite).  So this config item
doesnt do much when DRM_USE_DYNAMIC_DEBUG=y.

So this is a useful place to stop and look around, try to guess which
trail to take..

nouveau has additional debug variables to consider:

drivers/gpu/drm/nouveau/include/nvkm/core/device.h
131:	if (_device->debug >= (l))                                             \

drivers/gpu/drm/nouveau/include/nvkm/core/client.h
39:	if (_client->debug >= NV_DBG_##l)                                      \

drivers/gpu/drm/nouveau/include/nvkm/core/subdev.h
54:	if (CONFIG_NOUVEAU_DEBUG >= (l) && _subdev->debug >= (l))              \

This is another baby-step, that seems not to break, so lets get a
snapshot.

whats done here:

In nouveau_drm.c, do DECLARE_DYNDBG_CLASSMAP(LEVEL_NUM type) 2x more,
for cli and subdev, right after the drm DECLARE.  Adjust base for
each, to share the 0..30 classid-space.

These declare class-names: NV_CLI_DBG_* NV_SUBDEV_DBG_* accordingly.
Note: class-name-space is flat and wide, so super-generic names like
INFO should be prefixed; who could predict what a generic V3 does
across all modules.

s should be included

adjusting the base to avoid each other, and the 0-10
already mapped to drm-debug-categorys (just above this addition).

In nvkm/core/debug.h, add enums to match the names, with initial
values to match the bases.

In nvkm/core/subdev.h, alter (recently added) nvkm_drmdbg_() to use
NV_SUBDEV_DBG_* instead of NV_DBG_*.

NB: in both classmaps, Ive left FATAL..WARN out, they're not really
optional the way INFO..SPAM are; dyndbg shouldn't be able to turn them off.

bash-5.1# modprobe nouveau
[  966.107833] dyndbg:   3 debug prints in module wmi
[  966.342188] dyndbg: class[0]: module:nouveau base:15 len:5 ty:1
[  966.342873] dyndbg:  15: 0 NV_SUBDEV_DBG_OFF
[  966.343352] dyndbg:  16: 1 NV_SUBDEV_DBG_INFO
[  966.343912] dyndbg:  17: 2 NV_SUBDEV_DBG_DEBUG
[  966.344443] dyndbg:  18: 3 NV_SUBDEV_DBG_TRACE
[  966.344938] dyndbg:  19: 4 NV_SUBDEV_DBG_SPAM
[  966.345402] dyndbg: class[1]: module:nouveau base:10 len:5 ty:1
[  966.346011] dyndbg:  10: 0 NV_CLI_DBG_OFF
[  966.346477] dyndbg:  11: 1 NV_CLI_DBG_INFO
[  966.346989] dyndbg:  12: 2 NV_CLI_DBG_DEBUG
[  966.347442] dyndbg:  13: 3 NV_CLI_DBG_TRACE
[  966.347875] dyndbg:  14: 4 NV_CLI_DBG_SPAM
[  966.348284] dyndbg: class[2]: module:nouveau base:0 len:10 ty:0
[  966.348888] dyndbg:  0: 0 DRM_UT_CORE
[  966.349310] dyndbg:  1: 1 DRM_UT_DRIVER
[  966.349694] dyndbg:  2: 2 DRM_UT_KMS
[  966.350083] dyndbg:  3: 3 DRM_UT_PRIME
[  966.350482] dyndbg:  4: 4 DRM_UT_ATOMIC
[  966.351016] dyndbg:  5: 5 DRM_UT_VBL
[  966.351475] dyndbg:  6: 6 DRM_UT_STATE
[  966.351899] dyndbg:  7: 7 DRM_UT_LEASE
[  966.352309] dyndbg:  8: 8 DRM_UT_DP
[  966.352678] dyndbg:  9: 9 DRM_UT_DRMRES
[  966.353104] dyndbg: module:nouveau attached 3 classes
[  966.353759] dyndbg: 119 debug prints in module nouveau

NOTE: it was 632 with previous commit, switching NV_DEBUG to use
NV_SUBDEV_DBG_DEBUG instead of NV_DBG_DEBUG may be the cause.

Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
---
 .../gpu/drm/nouveau/include/nvkm/core/debug.h | 16 +++++++++++++
 .../drm/nouveau/include/nvkm/core/subdev.h    | 17 ++++++++++----
 drivers/gpu/drm/nouveau/nouveau_drm.c         |  7 ++++++
 drivers/gpu/drm/nouveau/nvkm/core/subdev.c    | 23 +++++++++++++++++++
 4 files changed, 59 insertions(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/nouveau/include/nvkm/core/debug.h b/drivers/gpu/drm/nouveau/include/nvkm/core/debug.h
index b4a9c7d991ca..6a155a23a3d1 100644
--- a/drivers/gpu/drm/nouveau/include/nvkm/core/debug.h
+++ b/drivers/gpu/drm/nouveau/include/nvkm/core/debug.h
@@ -9,4 +9,20 @@
 #define NV_DBG_TRACE    5
 #define NV_DBG_PARANOIA 6
 #define NV_DBG_SPAM     7
+
+enum nv_cli_dbg_verbose {
+	NV_CLI_DBG_OFF = 10,
+	NV_CLI_DBG_INFO,
+	NV_CLI_DBG_DEBUG,
+	NV_CLI_DBG_TRACE,
+	NV_CLI_DBG_SPAM
+};
+enum nv_subdev_dbg_verbose {
+	NV_SUBDEV_DBG_OFF = 15,
+	NV_SUBDEV_DBG_INFO,
+	NV_SUBDEV_DBG_DEBUG,
+	NV_SUBDEV_DBG_TRACE,
+	NV_SUBDEV_DBG_SPAM
+};
+
 #endif
diff --git a/drivers/gpu/drm/nouveau/include/nvkm/core/subdev.h b/drivers/gpu/drm/nouveau/include/nvkm/core/subdev.h
index 065d07ccea87..ce33c82e5c75 100644
--- a/drivers/gpu/drm/nouveau/include/nvkm/core/subdev.h
+++ b/drivers/gpu/drm/nouveau/include/nvkm/core/subdev.h
@@ -2,6 +2,7 @@
 #ifndef __NVKM_SUBDEV_H__
 #define __NVKM_SUBDEV_H__
 #include <core/device.h>
+#include <core/debug.h>
 
 enum nvkm_subdev_type {
 #define NVKM_LAYOUT_ONCE(t,s,p,...) t,
@@ -18,7 +19,7 @@ struct nvkm_subdev {
 	enum nvkm_subdev_type type;
 	int inst;
 	char name[16];
-	u32 debug;
+	unsigned long debug;
 	struct list_head head;
 
 	void **pself;
@@ -59,9 +60,17 @@ void nvkm_subdev_intr(struct nvkm_subdev *);
 #define nvkm_error(s,f,a...) nvkm_printk((s), ERROR,    err, f, ##a)
 #define nvkm_warn(s,f,a...)  nvkm_printk((s),  WARN, notice, f, ##a)
 #define nvkm_info(s,f,a...)  nvkm_printk((s),  INFO,   info, f, ##a)
-#define nvkm_debug(s,f,a...) nvkm_printk((s), DEBUG,    dbg, f, ##a)
-#define nvkm_trace(s,f,a...) nvkm_printk((s), TRACE,    dbg, f, ##a)
-#define nvkm_spam(s,f,a...)  nvkm_printk((s),  SPAM,    dbg, f, ##a)
+
+#define nvkm_drmdbg__(s,l,p,f,a...) do {				\
+	const struct nvkm_subdev *_subdev = (s);			\
+	if (CONFIG_NOUVEAU_DEBUG >= (l) && _subdev->debug >= (l))	\
+		dev_dbg(_subdev->device->dev, "%s: "f, _subdev->name, ##a); \
+} while(0)
+#define nvkm_drmdbg_(s,l,f,a...) nvkm_drmdbg__((s), NV_SUBDEV_DBG_##l, dbg, f, ##a)
+#define nvkm_debug(s,f,a...) nvkm_drmdbg_((s), DEBUG, f, ##a)
+#define nvkm_trace(s,f,a...) nvkm_drmdbg_((s), TRACE, f, ##a)
+#define nvkm_spam(s,f,a...)  nvkm_drmdbg_((s),  SPAM, f, ##a)
 
 #define nvkm_error_ratelimited(s,f,a...) nvkm_printk((s), ERROR, err_ratelimited, f, ##a)
+
 #endif
diff --git a/drivers/gpu/drm/nouveau/nouveau_drm.c b/drivers/gpu/drm/nouveau/nouveau_drm.c
index fd99ec0f4257..864750451dc8 100644
--- a/drivers/gpu/drm/nouveau/nouveau_drm.c
+++ b/drivers/gpu/drm/nouveau/nouveau_drm.c
@@ -83,6 +83,13 @@ DECLARE_DYNDBG_CLASSMAP(drm_debug_classes, DD_CLASS_TYPE_DISJOINT_BITS, 0,
 			"DRM_UT_DP",
 			"DRM_UT_DRMRES");
 
+DECLARE_DYNDBG_CLASSMAP(nv_cli_debug_verbose, DD_CLASS_TYPE_LEVEL_NUM, 10,
+			"NV_CLI_DBG_OFF",
+			"NV_CLI_DBG_INFO",
+			"NV_CLI_DBG_DEBUG",
+			"NV_CLI_DBG_TRACE",
+			"NV_CLI_DBG_SPAM");
+
 MODULE_PARM_DESC(config, "option string to pass to driver core");
 static char *nouveau_config;
 module_param_named(config, nouveau_config, charp, 0400);
diff --git a/drivers/gpu/drm/nouveau/nvkm/core/subdev.c b/drivers/gpu/drm/nouveau/nvkm/core/subdev.c
index a74b7acb6832..20cd99cce2a4 100644
--- a/drivers/gpu/drm/nouveau/nvkm/core/subdev.c
+++ b/drivers/gpu/drm/nouveau/nvkm/core/subdev.c
@@ -26,6 +26,27 @@
 #include <core/option.h>
 #include <subdev/mc.h>
 
+#include <linux/dynamic_debug.h>
+#include <linux/module.h>
+
+#define DEBUG
+
+DECLARE_DYNDBG_CLASSMAP(nv_subdev_debug_verbose, DD_CLASS_TYPE_LEVEL_NAMES, 15,
+			"NV_SUBDEV_DBG_OFF",
+			"NV_SUBDEV_DBG_INFO",
+			"NV_SUBDEV_DBG_DEBUG",
+			"NV_SUBDEV_DBG_TRACE",
+			"NV_SUBDEV_DBG_SPAM");
+
+static struct ddebug_class_param nv_subdev_verbose = {
+	.bits = NULL, // wants &_subdev->debug
+	.flags = "p",
+	.map = &nv_subdev_debug_verbose,
+};
+module_param_cb(debug_subdev, &param_ops_dyndbg_classes, &nv_subdev_verbose, 0600);
+
+
+
 const char *
 nvkm_subdev_type[NVKM_SUBDEV_NR] = {
 #define NVKM_LAYOUT_ONCE(type,data,ptr,...) [type] = #ptr,
@@ -180,6 +201,8 @@ nvkm_subdev_ctor(const struct nvkm_subdev_func *func, struct nvkm_device *device
 	else
 		strscpy(subdev->name, nvkm_subdev_type[type], sizeof(subdev->name));
 	subdev->debug = nvkm_dbgopt(device->dbgopt, subdev->name);
+	nv_subdev_verbose.bits = &subdev->debug;
+	pr_debug("updated bitmap: %px\n", &nv_subdev_verbose.bits);
 	list_add_tail(&subdev->head, &device->subdev);
 }
 
-- 
2.37.2

[PATCH v6 34/57] dyndbg: add _DPRINTK_FLAGS_ENABLED

[Jim Cromie]

Distinguish the condition: _DPRINTK_FLAGS_ENABLED from the bit:
_DPRINTK_FLAGS_PRINT, and re-define former in terms of latter, in
preparation to add a 2nd bit: _DPRINTK_FLAGS_TRACE

Update JUMP_LABEL code block to check _DPRINTK_FLAGS_ENABLED symbol.
Also add a 'K' to get new symbol _DPRINTK_FLAGS_PRINTK, in order to
break any stale uses.

CC: vincent.whitchurch@axis.com
Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
---
 include/linux/dynamic_debug.h | 10 ++++++----
 lib/dynamic_debug.c           |  8 ++++----
 2 files changed, 10 insertions(+), 8 deletions(-)

diff --git a/include/linux/dynamic_debug.h b/include/linux/dynamic_debug.h
index 41682278d2e8..ecd3379090c4 100644
--- a/include/linux/dynamic_debug.h
+++ b/include/linux/dynamic_debug.h
@@ -32,7 +32,7 @@ struct _ddebug {
 	 * writes commands to <debugfs>/dynamic_debug/control
 	 */
 #define _DPRINTK_FLAGS_NONE	0
-#define _DPRINTK_FLAGS_PRINT	(1<<0) /* printk() a message using the format */
+#define _DPRINTK_FLAGS_PRINTK	(1 << 0) /* printk() a message using the format */
 #define _DPRINTK_FLAGS_INCL_MODNAME	(1<<1)
 #define _DPRINTK_FLAGS_INCL_FUNCNAME	(1<<2)
 #define _DPRINTK_FLAGS_INCL_LINENO	(1<<3)
@@ -42,8 +42,10 @@ struct _ddebug {
 	(_DPRINTK_FLAGS_INCL_MODNAME | _DPRINTK_FLAGS_INCL_FUNCNAME |\
 	 _DPRINTK_FLAGS_INCL_LINENO  | _DPRINTK_FLAGS_INCL_TID)
 
+#define _DPRINTK_FLAGS_ENABLED		_DPRINTK_FLAGS_PRINTK
+
 #if defined DEBUG
-#define _DPRINTK_FLAGS_DEFAULT _DPRINTK_FLAGS_PRINT
+#define _DPRINTK_FLAGS_DEFAULT _DPRINTK_FLAGS_PRINTK
 #else
 #define _DPRINTK_FLAGS_DEFAULT 0
 #endif
@@ -198,10 +200,10 @@ void __dynamic_ibdev_dbg(struct _ddebug *descriptor,
 
 #ifdef DEBUG
 #define DYNAMIC_DEBUG_BRANCH(descriptor) \
-	likely(descriptor.flags & _DPRINTK_FLAGS_PRINT)
+	likely(descriptor.flags & _DPRINTK_FLAGS_ENABLED)
 #else
 #define DYNAMIC_DEBUG_BRANCH(descriptor) \
-	unlikely(descriptor.flags & _DPRINTK_FLAGS_PRINT)
+	unlikely(descriptor.flags & _DPRINTK_FLAGS_ENABLED)
 #endif
 
 #endif /* CONFIG_JUMP_LABEL */
diff --git a/lib/dynamic_debug.c b/lib/dynamic_debug.c
index 009f2ead09c1..1e9d0124a0e9 100644
--- a/lib/dynamic_debug.c
+++ b/lib/dynamic_debug.c
@@ -89,7 +89,7 @@ static inline const char *trim_prefix(const char *path)
 }
 
 static struct { unsigned flag:8; char opt_char; } opt_array[] = {
-	{ _DPRINTK_FLAGS_PRINT, 'p' },
+	{ _DPRINTK_FLAGS_PRINTK, 'p' },
 	{ _DPRINTK_FLAGS_INCL_MODNAME, 'm' },
 	{ _DPRINTK_FLAGS_INCL_FUNCNAME, 'f' },
 	{ _DPRINTK_FLAGS_INCL_LINENO, 'l' },
@@ -246,10 +246,10 @@ static int ddebug_change(const struct ddebug_query *query,
 			if (newflags == dp->flags)
 				continue;
 #ifdef CONFIG_JUMP_LABEL
-			if (dp->flags & _DPRINTK_FLAGS_PRINT) {
-				if (!(newflags & _DPRINTK_FLAGS_PRINT))
+			if (dp->flags & _DPRINTK_FLAGS_ENABLED) {
+				if (!(newflags & _DPRINTK_FLAGS_ENABLED))
 					static_branch_disable(&dp->key.dd_key_true);
-			} else if (newflags & _DPRINTK_FLAGS_PRINT) {
+			} else if (newflags & _DPRINTK_FLAGS_ENABLED) {
 				static_branch_enable(&dp->key.dd_key_true);
 			}
 #endif
-- 
2.37.2

[PATCH v6 35/57] dyndbg: add _DPRINTK_FLAGS_TRACE

[Jim Cromie]

add new flag, and OR it into _DPRINTK_FLAGS_ENABLED definition

CC: vincent.whitchurch@axis.com
Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
---
 include/linux/dynamic_debug.h | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/include/linux/dynamic_debug.h b/include/linux/dynamic_debug.h
index ecd3379090c4..04f49df308a7 100644
--- a/include/linux/dynamic_debug.h
+++ b/include/linux/dynamic_debug.h
@@ -42,7 +42,9 @@ struct _ddebug {
 	(_DPRINTK_FLAGS_INCL_MODNAME | _DPRINTK_FLAGS_INCL_FUNCNAME |\
 	 _DPRINTK_FLAGS_INCL_LINENO  | _DPRINTK_FLAGS_INCL_TID)
 
-#define _DPRINTK_FLAGS_ENABLED		_DPRINTK_FLAGS_PRINTK
+#define _DPRINTK_FLAGS_TRACE		(1 << 5)
+#define _DPRINTK_FLAGS_ENABLED		(_DPRINTK_FLAGS_PRINTK | \
+					 _DPRINTK_FLAGS_TRACE)
 
 #if defined DEBUG
 #define _DPRINTK_FLAGS_DEFAULT _DPRINTK_FLAGS_PRINTK
-- 
2.37.2

[PATCH v6 36/57] dyndbg: add write-events-to-tracefs code

[Jim Cromie]

adds: ddebug_trace()
 uses trace_console() temporarily to issue printk:console event
 uses internal-ish __ftrace_trace_stack code:
      4-context buffer stack, barriers per Steve Rostedt

call it from new funcs:
  ddebug_printk() - print to both syslog/tracefs
  ddebug_dev_printk() - dev-print to both syslog/tracefs

These handle both _DPRINTK_FLAGS_PRINTK and _DPRINTK_FLAGS_TRACE
cases, allowing to vsnprintf the message once and use it for both,
skipping past the KERN_DEBUG character for tracing.

Finally, adjust the callers: __ddebug_{pr_debug,{,net,ib}dev_dbg},
replacing printk and dev_printk with the new funcs above.

The _DPRINTK_FLAGS_TRACE flag character is 'T', so the following finds
all callsites enabled for tracing:

  grep -P =p?T /proc/dynamic_debug/control

This patch,~1,~2 are basically copies of:
  https://lore.kernel.org/lkml/20200825153338.17061-1-vincent.whitchurch@axis.com/

with a few differences:

- s/dynamic_/ddebug_/ on Vincent's additions
- __printf attrs on the _printk funcs
- reuses trace_console() event, not adding a new "printk:dyndbg" event.
  next patch replaces this with 2 new events

CC: vincent.whitchurch@axis.com
Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
---
 .../admin-guide/dynamic-debug-howto.rst       |   5 +-
 lib/dynamic_debug.c                           | 156 +++++++++++++++---
 2 files changed, 133 insertions(+), 28 deletions(-)

diff --git a/Documentation/admin-guide/dynamic-debug-howto.rst b/Documentation/admin-guide/dynamic-debug-howto.rst
index faa22f77847a..45b6e5697c89 100644
--- a/Documentation/admin-guide/dynamic-debug-howto.rst
+++ b/Documentation/admin-guide/dynamic-debug-howto.rst
@@ -209,8 +209,9 @@ of the characters::
 
 The flags are::
 
-  p    enables the pr_debug() callsite.
-  _    enables no flags.
+  p    callsite prints to syslog
+  T    callsite issues a dyndbg:* trace-event
+  _    enables no flags
 
   Decorator flags add to the message-prefix, in order:
   t    Include thread ID, or <intr>
diff --git a/lib/dynamic_debug.c b/lib/dynamic_debug.c
index 1e9d0124a0e9..3c6c18f13889 100644
--- a/lib/dynamic_debug.c
+++ b/lib/dynamic_debug.c
@@ -36,6 +36,7 @@
 #include <linux/sched.h>
 #include <linux/device.h>
 #include <linux/netdevice.h>
+#include <trace/events/printk.h>
 
 #include <rdma/ib_verbs.h>
 
@@ -90,6 +91,7 @@ static inline const char *trim_prefix(const char *path)
 
 static struct { unsigned flag:8; char opt_char; } opt_array[] = {
 	{ _DPRINTK_FLAGS_PRINTK, 'p' },
+	{ _DPRINTK_FLAGS_TRACE, 'T' },
 	{ _DPRINTK_FLAGS_INCL_MODNAME, 'm' },
 	{ _DPRINTK_FLAGS_INCL_FUNCNAME, 'f' },
 	{ _DPRINTK_FLAGS_INCL_LINENO, 'l' },
@@ -854,6 +856,98 @@ static inline char *dynamic_emit_prefix(struct _ddebug *desc, char *buf)
 	return buf;
 }
 
+/*
+ * This code is heavily based on __ftrace_trace_stack().
+ *
+ * Allow 4 levels of nesting: normal, softirq, irq, NMI.
+ */
+#define DYNAMIC_TRACE_NESTING	4
+
+struct ddebug_trace_buf {
+	char buf[256];
+};
+
+struct ddebug_trace_bufs {
+	struct ddebug_trace_buf bufs[DYNAMIC_TRACE_NESTING];
+};
+
+static DEFINE_PER_CPU(struct ddebug_trace_bufs, ddebug_trace_bufs);
+static DEFINE_PER_CPU(int, ddebug_trace_reserve);
+
+static void ddebug_trace(const char *fmt, va_list args)
+{
+	struct ddebug_trace_buf *buf;
+	int bufidx;
+	int len;
+
+	preempt_disable_notrace();
+
+	bufidx = __this_cpu_inc_return(ddebug_trace_reserve) - 1;
+
+	if (WARN_ON_ONCE(bufidx > DYNAMIC_TRACE_NESTING))
+		goto out;
+
+	/* For the same reasons as in __ftrace_trace_stack(). */
+	barrier();
+
+	buf = this_cpu_ptr(ddebug_trace_bufs.bufs) + bufidx;
+
+	len = vscnprintf(buf->buf, sizeof(buf->buf), fmt, args);
+	trace_console(buf->buf, len);
+
+out:
+	/* As above. */
+	barrier();
+	__this_cpu_dec(ddebug_trace_reserve);
+	preempt_enable_notrace();
+}
+
+__printf(2, 3)
+static void ddebug_printk(unsigned int flags, const char *fmt, ...)
+{
+	if (flags & _DPRINTK_FLAGS_TRACE) {
+		va_list args;
+
+		va_start(args, fmt);
+		/*
+		 * All callers include the KERN_DEBUG prefix to keep the
+		 * vprintk case simple; strip it out for tracing.
+		 */
+		ddebug_trace(fmt + strlen(KERN_DEBUG), args);
+		va_end(args);
+	}
+
+	if (flags & _DPRINTK_FLAGS_PRINTK) {
+		va_list args;
+
+		va_start(args, fmt);
+		vprintk(fmt, args);
+		va_end(args);
+	}
+}
+
+__printf(3, 4)
+static void ddebug_dev_printk(unsigned int flags, const struct device *dev,
+			      const char *fmt, ...)
+{
+
+	if (flags & _DPRINTK_FLAGS_TRACE) {
+		va_list args;
+
+		va_start(args, fmt);
+		ddebug_trace(fmt, args);
+		va_end(args);
+	}
+
+	if (flags & _DPRINTK_FLAGS_PRINTK) {
+		va_list args;
+
+		va_start(args, fmt);
+		dev_vprintk_emit(LOGLEVEL_DEBUG, dev, fmt, args);
+		va_end(args);
+	}
+}
+
 void __dynamic_pr_debug(struct _ddebug *descriptor, const char *fmt, ...)
 {
 	va_list args;
@@ -868,16 +962,18 @@ void __dynamic_pr_debug(struct _ddebug *descriptor, const char *fmt, ...)
 	vaf.fmt = fmt;
 	vaf.va = &args;
 
-	printk(KERN_DEBUG "%s%pV", dynamic_emit_prefix(descriptor, buf), &vaf);
+	ddebug_printk(descriptor->flags, KERN_DEBUG "%s%pV",
+		      dynamic_emit_prefix(descriptor, buf), &vaf);
 
 	va_end(args);
 }
 EXPORT_SYMBOL(__dynamic_pr_debug);
 
 void __dynamic_dev_dbg(struct _ddebug *descriptor,
-		      const struct device *dev, const char *fmt, ...)
+		       const struct device *dev, const char *fmt, ...)
 {
 	struct va_format vaf;
+	unsigned int flags;
 	va_list args;
 
 	BUG_ON(!descriptor);
@@ -887,16 +983,18 @@ void __dynamic_dev_dbg(struct _ddebug *descriptor,
 
 	vaf.fmt = fmt;
 	vaf.va = &args;
+	flags = descriptor->flags;
 
 	if (!dev) {
-		printk(KERN_DEBUG "(NULL device *): %pV", &vaf);
+		ddebug_printk(flags, KERN_DEBUG "(NULL device *): %pV",
+			      &vaf);
 	} else {
 		char buf[PREFIX_SIZE] = "";
 
-		dev_printk_emit(LOGLEVEL_DEBUG, dev, "%s%s %s: %pV",
-				dynamic_emit_prefix(descriptor, buf),
-				dev_driver_string(dev), dev_name(dev),
-				&vaf);
+		ddebug_dev_printk(flags, dev, "%s%s %s: %pV",
+				  dynamic_emit_prefix(descriptor, buf),
+				  dev_driver_string(dev), dev_name(dev),
+				  &vaf);
 	}
 
 	va_end(args);
@@ -909,6 +1007,7 @@ void __dynamic_netdev_dbg(struct _ddebug *descriptor,
 			  const struct net_device *dev, const char *fmt, ...)
 {
 	struct va_format vaf;
+	unsigned int flags;
 	va_list args;
 
 	BUG_ON(!descriptor);
@@ -918,22 +1017,24 @@ void __dynamic_netdev_dbg(struct _ddebug *descriptor,
 
 	vaf.fmt = fmt;
 	vaf.va = &args;
+	flags = descriptor->flags;
 
 	if (dev && dev->dev.parent) {
 		char buf[PREFIX_SIZE] = "";
 
-		dev_printk_emit(LOGLEVEL_DEBUG, dev->dev.parent,
-				"%s%s %s %s%s: %pV",
-				dynamic_emit_prefix(descriptor, buf),
-				dev_driver_string(dev->dev.parent),
-				dev_name(dev->dev.parent),
-				netdev_name(dev), netdev_reg_state(dev),
-				&vaf);
+		ddebug_dev_printk(flags, dev->dev.parent,
+				   "%s%s %s %s%s: %pV",
+				   dynamic_emit_prefix(descriptor, buf),
+				   dev_driver_string(dev->dev.parent),
+				   dev_name(dev->dev.parent),
+				   netdev_name(dev), netdev_reg_state(dev),
+				   &vaf);
 	} else if (dev) {
-		printk(KERN_DEBUG "%s%s: %pV", netdev_name(dev),
-		       netdev_reg_state(dev), &vaf);
+		ddebug_printk(flags, KERN_DEBUG "%s%s: %pV",
+			       netdev_name(dev), netdev_reg_state(dev), &vaf);
 	} else {
-		printk(KERN_DEBUG "(NULL net_device): %pV", &vaf);
+		ddebug_printk(flags, KERN_DEBUG "(NULL net_device): %pV",
+			       &vaf);
 	}
 
 	va_end(args);
@@ -949,26 +1050,29 @@ void __dynamic_ibdev_dbg(struct _ddebug *descriptor,
 {
 	struct va_format vaf;
 	va_list args;
+	unsigned int flags;
 
 	va_start(args, fmt);
 
 	vaf.fmt = fmt;
 	vaf.va = &args;
+	flags = descriptor->flags;
 
 	if (ibdev && ibdev->dev.parent) {
 		char buf[PREFIX_SIZE] = "";
 
-		dev_printk_emit(LOGLEVEL_DEBUG, ibdev->dev.parent,
-				"%s%s %s %s: %pV",
-				dynamic_emit_prefix(descriptor, buf),
-				dev_driver_string(ibdev->dev.parent),
-				dev_name(ibdev->dev.parent),
-				dev_name(&ibdev->dev),
-				&vaf);
+		ddebug_dev_printk(flags, ibdev->dev.parent,
+				  "%s%s %s %s: %pV",
+				  dynamic_emit_prefix(descriptor, buf),
+				  dev_driver_string(ibdev->dev.parent),
+				  dev_name(ibdev->dev.parent),
+				  dev_name(&ibdev->dev),
+				  &vaf);
 	} else if (ibdev) {
-		printk(KERN_DEBUG "%s: %pV", dev_name(&ibdev->dev), &vaf);
+		ddebug_printk(flags, KERN_DEBUG "%s: %pV",
+			      dev_name(&ibdev->dev), &vaf);
 	} else {
-		printk(KERN_DEBUG "(NULL ib_device): %pV", &vaf);
+		ddebug_printk(flags, KERN_DEBUG "(NULL ip_device): %pV", &vaf);
 	}
 
 	va_end(args);
-- 
2.37.2

[PATCH v6 37/57] dyndbg: add 2 trace-events: drm_debug, drm_devdbg

[Jim Cromie]

Recently added ddebug_trace() issues a single printk:console event.
Replace that event with 2 new ones, defined in a new header:
include/trace/events/dyndbg.h

- dyndbg:prdbg  - from trace_prdbg()  - if !dev
- dyndbg:devdbg - from trace_devdbg() - if !!dev

This links the legacy pr_debug API to tracefs, so pr_debug() and
dev_dbg() calls can add more debug context into the trace-logs, and
then at users option, less into syslog.

The new events allow enabling by event-type in tracefs, and dyndbg
allows individual enablement of prdbg callsites (via +T flag).

Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
---
 drivers/gpu/drm/drm_print.c | 25 ++++++++++++-----
 include/trace/events/drm.h  | 54 +++++++++++++++++++++++++++++++++++++
 2 files changed, 72 insertions(+), 7 deletions(-)
 create mode 100644 include/trace/events/drm.h

diff --git a/drivers/gpu/drm/drm_print.c b/drivers/gpu/drm/drm_print.c
index 5b93c11895bb..c50edbf443d3 100644
--- a/drivers/gpu/drm/drm_print.c
+++ b/drivers/gpu/drm/drm_print.c
@@ -35,6 +35,9 @@
 #include <drm/drm_drv.h>
 #include <drm/drm_print.h>
 
+#define CREATE_TRACE_POINTS
+#include <trace/events/drm.h>
+
 /*
  * __drm_debug: Enable debug output.
  * Bitmask of DRM_UT_x. See include/drm/drm_print.h for details.
@@ -293,13 +296,19 @@ void __drm_dev_dbg(struct _ddebug *desc, const struct device *dev,
 	vaf.fmt = format;
 	vaf.va = &args;
 
-	if (dev)
-		dev_printk(KERN_DEBUG, dev, "[" DRM_NAME ":%ps] %pV",
-			   __builtin_return_address(0), &vaf);
-	else
-		printk(KERN_DEBUG "[" DRM_NAME ":%ps] %pV",
-		       __builtin_return_address(0), &vaf);
-
+	if (dev) {
+		if (desc->flags & _DPRINTK_FLAGS_PRINTK)
+			dev_printk(KERN_DEBUG, dev, "[" DRM_NAME ":%ps] %pV",
+				   __builtin_return_address(0), &vaf);
+		if (desc->flags & _DPRINTK_FLAGS_TRACE)
+			trace_drm_devdbg(dev, category, &vaf);
+	} else {
+		if (desc->flags & _DPRINTK_FLAGS_PRINTK)
+			printk(KERN_DEBUG "[" DRM_NAME ":%ps] %pV",
+			       __builtin_return_address(0), &vaf);
+		if (desc->flags & _DPRINTK_FLAGS_TRACE)
+			trace_drm_debug(category, &vaf);
+	}
 	va_end(args);
 }
 EXPORT_SYMBOL(__drm_dev_dbg);
@@ -319,6 +328,8 @@ void ___drm_dbg(struct _ddebug *desc, enum drm_debug_category category, const ch
 	printk(KERN_DEBUG "[" DRM_NAME ":%ps] %pV",
 	       __builtin_return_address(0), &vaf);
 
+	trace_drm_debug(category, &vaf);
+
 	va_end(args);
 }
 EXPORT_SYMBOL(___drm_dbg);
diff --git a/include/trace/events/drm.h b/include/trace/events/drm.h
new file mode 100644
index 000000000000..589fa1e1f2c2
--- /dev/null
+++ b/include/trace/events/drm.h
@@ -0,0 +1,54 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#undef TRACE_SYSTEM
+#define TRACE_SYSTEM drm
+
+#if !defined(_TRACE_DRM_H) || defined(TRACE_HEADER_MULTI_READ)
+#define _TRACE_DRM_H
+
+#include <linux/tracepoint.h>
+
+/* drm_debug() was called, pass its args */
+TRACE_EVENT(drm_debug,
+	    TP_PROTO(int drm_debug_category, struct va_format *vaf),
+
+	    TP_ARGS(drm_debug_category, vaf),
+
+	    TP_STRUCT__entry(
+		    __field(int, drm_debug_category)
+		    __vstring(msg, vaf->fmt, vaf->va)
+		    ),
+
+	    TP_fast_assign(
+		    __entry->drm_debug_category = drm_debug_category;
+		    __assign_vstr(msg, vaf->fmt, vaf->va);
+		    ),
+
+	    TP_printk("%s", __get_str(msg))
+);
+
+/* drm_devdbg() was called, pass its args, preserving order */
+TRACE_EVENT(drm_devdbg,
+	    TP_PROTO(const struct device *dev, int drm_debug_category, struct va_format *vaf),
+
+	    TP_ARGS(dev, drm_debug_category, vaf),
+
+	    TP_STRUCT__entry(
+		    __field(const struct device*, dev)
+		    __field(int, drm_debug_category)
+		    __vstring(msg, vaf->fmt, vaf->va)
+		    ),
+
+	    TP_fast_assign(
+		    __entry->drm_debug_category = drm_debug_category;
+		    __entry->dev = dev;
+		    __assign_vstr(msg, vaf->fmt, vaf->va);
+		    ),
+
+	    TP_printk("cat:%d, %s %s", __entry->drm_debug_category,
+		      dev_name(__entry->dev), __get_str(msg))
+);
+
+#endif /* _TRACE_DRM_H */
+
+/* This part must be outside protection */
+#include <trace/define_trace.h>
-- 
2.37.2

[PATCH v6 38/57] dyndbg: add 2 more trace-events: pr_debug, dev_dbg

[Jim Cromie]

ddebug_trace() currently issues a single printk:console event.
Replace that, adding include/trace/events/dyndbg.h, which defines 2
new events:

- dyndbg:prdbg  - from trace_prdbg()  - if !dev
- dyndbg:devdbg - from trace_devdbg() - if !!dev

This links the legacy pr_debug API to tracefs, via dyndbg, allowing
pr_debug()s etc to add just a little more user-context to the
trace-logs, and then at users option, less syslog.

The 2 new trace_*() calls accept their caller's args respectively,
keeping the available info w/o alteration; we can't improve on
transparency.  The args:

 1- struct _ddebug *descriptor, giving tracefs all of dyndbg's info.
 2- struct device *dev, used by trace_devdbg(), if !!dev

The trace_*() calls need the descriptor arg, the callchain prototypes
above them are extended to provide it.

The existing category param in this callchain is partially redundant;
when descriptor is available, it has the class_id.

dev_dbg(desc, dev...), if dev is true, issues a trace_devdbg(),
otherwise trace_prdbg().  This way we dont consume buffer space
storing nulls.  Otherwise the events are equivalent.

Also add include/trace/events/drm.h, to create 2 events for use in
drm_dbg() and drm_devdbg(), and call them.  This recapitulates the
changes described above, connecting 3-10K drm.debug callsites to
tracefs.

Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
---
 include/trace/events/dyndbg.h | 74 +++++++++++++++++++++++++++++++++++
 lib/dynamic_debug.c           | 73 +++++++++++++++++-----------------
 2 files changed, 111 insertions(+), 36 deletions(-)
 create mode 100644 include/trace/events/dyndbg.h

diff --git a/include/trace/events/dyndbg.h b/include/trace/events/dyndbg.h
new file mode 100644
index 000000000000..e19fcb56566c
--- /dev/null
+++ b/include/trace/events/dyndbg.h
@@ -0,0 +1,74 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#undef TRACE_SYSTEM
+#define TRACE_SYSTEM dyndbg
+
+#if !defined(_TRACE_DYNDBG_H) || defined(TRACE_HEADER_MULTI_READ)
+#define _TRACE_DYNDBG_H
+
+#include <linux/tracepoint.h>
+
+/* capture pr_debug() callsite descriptor and message */
+TRACE_EVENT(prdbg,
+	    TP_PROTO(const struct _ddebug *desc, const char *text, size_t len),
+
+	    TP_ARGS(desc, text, len),
+
+	    TP_STRUCT__entry(
+		    __field(const struct _ddebug *, desc)
+		    __dynamic_array(char, msg, len + 1)
+		    ),
+
+	    TP_fast_assign(
+		    __entry->desc = desc;
+		    /*
+		     * Each trace entry is printed in a new line.
+		     * If the msg finishes with '\n', cut it off
+		     * to avoid blank lines in the trace.
+		     */
+		    if (len > 0 && (text[len - 1] == '\n'))
+			    len -= 1;
+
+		    memcpy(__get_str(msg), text, len);
+		    __get_str(msg)[len] = 0;
+		    ),
+
+	    TP_printk("%s.%s %s", __entry->desc->modname,
+		      __entry->desc->function, __get_str(msg))
+);
+
+/* capture dev_dbg() callsite descriptor, device, and message */
+TRACE_EVENT(devdbg,
+	    TP_PROTO(const struct _ddebug *desc, const struct device *dev,
+		     const char *text, size_t len),
+
+	    TP_ARGS(desc, dev, text, len),
+
+	    TP_STRUCT__entry(
+		    __field(const struct _ddebug *, desc)
+		    __field(const struct device *, dev)
+		    __dynamic_array(char, msg, len + 1)
+		    ),
+
+	    TP_fast_assign(
+		    __entry->desc = desc;
+		    __entry->dev = (struct device *) dev;
+		    /*
+		     * Each trace entry is printed in a new line.
+		     * If the msg finishes with '\n', cut it off
+		     * to avoid blank lines in the trace.
+		     */
+		    if (len > 0 && (text[len - 1] == '\n'))
+			    len -= 1;
+
+		    memcpy(__get_str(msg), text, len);
+		    __get_str(msg)[len] = 0;
+		    ),
+
+	    TP_printk("%s.%s %s", __entry->desc->modname,
+		      __entry->desc->function, __get_str(msg))
+);
+
+#endif /* _TRACE_DYNDBG_H */
+
+/* This part must be outside protection */
+#include <trace/define_trace.h>
diff --git a/lib/dynamic_debug.c b/lib/dynamic_debug.c
index 3c6c18f13889..0870e939f255 100644
--- a/lib/dynamic_debug.c
+++ b/lib/dynamic_debug.c
@@ -36,7 +36,9 @@
 #include <linux/sched.h>
 #include <linux/device.h>
 #include <linux/netdevice.h>
-#include <trace/events/printk.h>
+
+#define CREATE_TRACE_POINTS
+#include <trace/events/dyndbg.h>
 
 #include <rdma/ib_verbs.h>
 
@@ -874,7 +876,9 @@ struct ddebug_trace_bufs {
 static DEFINE_PER_CPU(struct ddebug_trace_bufs, ddebug_trace_bufs);
 static DEFINE_PER_CPU(int, ddebug_trace_reserve);
 
-static void ddebug_trace(const char *fmt, va_list args)
+__printf(3, 0)
+static void ddebug_trace(struct _ddebug *desc, const struct device *dev,
+			 const char *fmt, va_list args)
 {
 	struct ddebug_trace_buf *buf;
 	int bufidx;
@@ -893,7 +897,11 @@ static void ddebug_trace(const char *fmt, va_list args)
 	buf = this_cpu_ptr(ddebug_trace_bufs.bufs) + bufidx;
 
 	len = vscnprintf(buf->buf, sizeof(buf->buf), fmt, args);
-	trace_console(buf->buf, len);
+
+	if (!dev)
+		trace_prdbg(desc, buf->buf, len);
+	else
+		trace_devdbg(desc, dev, buf->buf, len);
 
 out:
 	/* As above. */
@@ -903,9 +911,9 @@ static void ddebug_trace(const char *fmt, va_list args)
 }
 
 __printf(2, 3)
-static void ddebug_printk(unsigned int flags, const char *fmt, ...)
+static void ddebug_printk(struct _ddebug *desc, const char *fmt, ...)
 {
-	if (flags & _DPRINTK_FLAGS_TRACE) {
+	if (desc->flags & _DPRINTK_FLAGS_TRACE) {
 		va_list args;
 
 		va_start(args, fmt);
@@ -913,11 +921,11 @@ static void ddebug_printk(unsigned int flags, const char *fmt, ...)
 		 * All callers include the KERN_DEBUG prefix to keep the
 		 * vprintk case simple; strip it out for tracing.
 		 */
-		ddebug_trace(fmt + strlen(KERN_DEBUG), args);
+		ddebug_trace(desc, NULL, fmt + strlen(KERN_DEBUG), args);
 		va_end(args);
 	}
 
-	if (flags & _DPRINTK_FLAGS_PRINTK) {
+	if (desc->flags & _DPRINTK_FLAGS_PRINTK) {
 		va_list args;
 
 		va_start(args, fmt);
@@ -927,19 +935,19 @@ static void ddebug_printk(unsigned int flags, const char *fmt, ...)
 }
 
 __printf(3, 4)
-static void ddebug_dev_printk(unsigned int flags, const struct device *dev,
+static void ddebug_dev_printk(struct _ddebug *desc, const struct device *dev,
 			      const char *fmt, ...)
 {
 
-	if (flags & _DPRINTK_FLAGS_TRACE) {
+	if (desc->flags & _DPRINTK_FLAGS_TRACE) {
 		va_list args;
 
 		va_start(args, fmt);
-		ddebug_trace(fmt, args);
+		ddebug_trace(desc, dev, fmt, args);
 		va_end(args);
 	}
 
-	if (flags & _DPRINTK_FLAGS_PRINTK) {
+	if (desc->flags & _DPRINTK_FLAGS_PRINTK) {
 		va_list args;
 
 		va_start(args, fmt);
@@ -962,7 +970,7 @@ void __dynamic_pr_debug(struct _ddebug *descriptor, const char *fmt, ...)
 	vaf.fmt = fmt;
 	vaf.va = &args;
 
-	ddebug_printk(descriptor->flags, KERN_DEBUG "%s%pV",
+	ddebug_printk(descriptor, KERN_DEBUG "%s%pV",
 		      dynamic_emit_prefix(descriptor, buf), &vaf);
 
 	va_end(args);
@@ -973,7 +981,6 @@ void __dynamic_dev_dbg(struct _ddebug *descriptor,
 		       const struct device *dev, const char *fmt, ...)
 {
 	struct va_format vaf;
-	unsigned int flags;
 	va_list args;
 
 	BUG_ON(!descriptor);
@@ -983,15 +990,14 @@ void __dynamic_dev_dbg(struct _ddebug *descriptor,
 
 	vaf.fmt = fmt;
 	vaf.va = &args;
-	flags = descriptor->flags;
 
 	if (!dev) {
-		ddebug_printk(flags, KERN_DEBUG "(NULL device *): %pV",
-			      &vaf);
+		ddebug_printk(descriptor, KERN_DEBUG "(NULL device *): %pV",
+			       &vaf);
 	} else {
 		char buf[PREFIX_SIZE] = "";
 
-		ddebug_dev_printk(flags, dev, "%s%s %s: %pV",
+		ddebug_dev_printk(descriptor, dev, "%s%s %s: %pV",
 				  dynamic_emit_prefix(descriptor, buf),
 				  dev_driver_string(dev), dev_name(dev),
 				  &vaf);
@@ -1007,7 +1013,6 @@ void __dynamic_netdev_dbg(struct _ddebug *descriptor,
 			  const struct net_device *dev, const char *fmt, ...)
 {
 	struct va_format vaf;
-	unsigned int flags;
 	va_list args;
 
 	BUG_ON(!descriptor);
@@ -1017,24 +1022,22 @@ void __dynamic_netdev_dbg(struct _ddebug *descriptor,
 
 	vaf.fmt = fmt;
 	vaf.va = &args;
-	flags = descriptor->flags;
 
 	if (dev && dev->dev.parent) {
 		char buf[PREFIX_SIZE] = "";
 
-		ddebug_dev_printk(flags, dev->dev.parent,
-				   "%s%s %s %s%s: %pV",
-				   dynamic_emit_prefix(descriptor, buf),
-				   dev_driver_string(dev->dev.parent),
-				   dev_name(dev->dev.parent),
-				   netdev_name(dev), netdev_reg_state(dev),
-				   &vaf);
+		ddebug_dev_printk(descriptor, dev->dev.parent,
+				  "%s%s %s %s%s: %pV",
+				  dynamic_emit_prefix(descriptor, buf),
+				  dev_driver_string(dev->dev.parent),
+				  dev_name(dev->dev.parent),
+				  netdev_name(dev), netdev_reg_state(dev),
+				  &vaf);
 	} else if (dev) {
-		ddebug_printk(flags, KERN_DEBUG "%s%s: %pV",
-			       netdev_name(dev), netdev_reg_state(dev), &vaf);
+		ddebug_dev_printk(descriptor, &dev->dev, KERN_DEBUG "%s%s: %pV",
+				  netdev_name(dev), netdev_reg_state(dev), &vaf);
 	} else {
-		ddebug_printk(flags, KERN_DEBUG "(NULL net_device): %pV",
-			       &vaf);
+		ddebug_printk(descriptor, KERN_DEBUG "(NULL net_device): %pV", &vaf);
 	}
 
 	va_end(args);
@@ -1050,18 +1053,16 @@ void __dynamic_ibdev_dbg(struct _ddebug *descriptor,
 {
 	struct va_format vaf;
 	va_list args;
-	unsigned int flags;
 
 	va_start(args, fmt);
 
 	vaf.fmt = fmt;
 	vaf.va = &args;
-	flags = descriptor->flags;
 
 	if (ibdev && ibdev->dev.parent) {
 		char buf[PREFIX_SIZE] = "";
 
-		ddebug_dev_printk(flags, ibdev->dev.parent,
+		ddebug_dev_printk(descriptor, ibdev->dev.parent,
 				  "%s%s %s %s: %pV",
 				  dynamic_emit_prefix(descriptor, buf),
 				  dev_driver_string(ibdev->dev.parent),
@@ -1069,10 +1070,10 @@ void __dynamic_ibdev_dbg(struct _ddebug *descriptor,
 				  dev_name(&ibdev->dev),
 				  &vaf);
 	} else if (ibdev) {
-		ddebug_printk(flags, KERN_DEBUG "%s: %pV",
-			      dev_name(&ibdev->dev), &vaf);
+		ddebug_dev_printk(descriptor, &ibdev->dev, KERN_DEBUG "%s: %pV",
+				  dev_name(&ibdev->dev), &vaf);
 	} else {
-		ddebug_printk(flags, KERN_DEBUG "(NULL ip_device): %pV", &vaf);
+		ddebug_printk(descriptor, KERN_DEBUG "(NULL ip_device): %pV", &vaf);
 	}
 
 	va_end(args);
-- 
2.37.2

[PATCH v6 39/57] dyndbg/drm: POC add tracebits sysfs-knob

[Jim Cromie]

clone DRM.debug interface to DRM.tracebits: ie map bits to
drm-debug-categories, except this interface enables messages to
tracefs, not to syslog.

1- we reuse the class-map added previously.
   this reflects the single source of both syslog/trace events

2- add a 2nd struct ddebug_classes_bitmap_param
   refs 1, reusing it.
   flags = "T", to enable trace-events on this callsite.

3- module_param_cb([2]) - does the sysfs part

Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
---
 drivers/gpu/drm/drm_print.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/drivers/gpu/drm/drm_print.c b/drivers/gpu/drm/drm_print.c
index c50edbf443d3..75d0cecd7e86 100644
--- a/drivers/gpu/drm/drm_print.c
+++ b/drivers/gpu/drm/drm_print.c
@@ -45,6 +45,9 @@
 unsigned long __drm_debug;
 EXPORT_SYMBOL(__drm_debug);
 
+unsigned long __drm_trace;
+EXPORT_SYMBOL(__drm_trace);
+
 MODULE_PARM_DESC(debug, "Enable debug output, where each bit enables a debug category.\n"
 "\t\tBit 0 (0x01)  will enable CORE messages (drm core code)\n"
 "\t\tBit 1 (0x02)  will enable DRIVER messages (drm controller code)\n"
@@ -77,6 +80,13 @@ static struct ddebug_class_param drm_debug_bitmap = {
 	.map = &drm_debug_classes,
 };
 module_param_cb(debug, &param_ops_dyndbg_classes, &drm_debug_bitmap, 0600);
+
+static struct ddebug_class_param drm_trace_bitmap = {
+	.bits = &__drm_trace,
+	.flags = "T",
+	.map = &drm_debug_classes,
+};
+module_param_cb(tracecats, &param_ops_dyndbg_classes, &drm_trace_bitmap, 0600);
 #endif
 
 void __drm_puts_coredump(struct drm_printer *p, const char *str)
-- 
2.37.2

[PATCH v6 40/57] dyndbg: abstraction macros for modname, function, filename fields

[Jim Cromie]

The .data table built of struct _ddebug[]s has about 40% repetition in
the "decorator" fields: modname, function, filename.  The real fix is
to "normalize the db", but 1st we need a layer of accessor macros,
giving us just one field deref to alter later.

So:
 define 3 field-abstraction macros: desc_{modname,function,filename}(desc).
 replace all raw field refs in lib/dynamic_debug.c with them.

The macros protect against NULL pointer derefs, substituting "_na_"
otherwise.  This provides a generic guard, opening options to drop the
contents of __dyndbg_sites[] opportunistically, and trim kernel/module
data.  DRM, which could use only .class_id to control drm.debug, could
drop them.

The 3 macros use a common foundation: _ddebug_map_site(), which will
adapt to follow the coming table-split.

Also change field names; adding '_' prefix to insure that bare
field-refs are found and fixed.  Most field uses get the macros,
except for dynamic_debug_init(), which will need to follow the
rearrangements.

NOTE: macros are private, not currently for general use.

trace/events/dyndbg.h was a candidate to use these macros, for which I
included the header. On rethink, these macros are wrong abstraction
for tracing; better to expose a dynamic_prefix_emit(1) flavor, and use
it in TP_printk to "decorate" enabled trace-logs like it does for
sys-logs.

So this patch removes the raw field-refs rather than use the macros.
I left the include to mark the intention to use privatish interfaces,
see if it draws objections or compile errs.

[1] fills caller provided char-buffer, perhaps not ideal for tracefs.
A fixed max-size-possible per-callsite (or globally) is practical, but
the struct _ddebug_site * val is probably best; it refs a prdbg's
site-rec of a builtin or loadable module, which is unique over the
pertinent lifetime, and has all the info.

WAG,TLDR: "decorating" could be defered until `cat trace`, modulo
loadable sites[] data being needed to render after module is unloaded.

no functional changes.

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

TP-print-dont-use-desc-foo
---
 include/linux/dynamic_debug.h | 12 ++++++------
 include/trace/events/dyndbg.h |  7 +++----
 lib/dynamic_debug.c           | 37 ++++++++++++++++++++++-------------
 3 files changed, 32 insertions(+), 24 deletions(-)

diff --git a/include/linux/dynamic_debug.h b/include/linux/dynamic_debug.h
index 04f49df308a7..e04f5b0a31e2 100644
--- a/include/linux/dynamic_debug.h
+++ b/include/linux/dynamic_debug.h
@@ -18,9 +18,9 @@ struct _ddebug {
 	 * These fields are used to drive the user interface
 	 * for selecting and displaying debug callsites.
 	 */
-	const char *modname;
-	const char *function;
-	const char *filename;
+	const char *_modname;
+	const char *_function;
+	const char *_filename;
 	const char *format;
 	unsigned int lineno:18;
 #define CLS_BITS 6
@@ -166,9 +166,9 @@ void __dynamic_ibdev_dbg(struct _ddebug *descriptor,
 #define DEFINE_DYNAMIC_DEBUG_METADATA_CLS(name, cls, fmt)	\
 	static struct _ddebug  __aligned(8)			\
 	__section("__dyndbg") name = {				\
-		.modname = KBUILD_MODNAME,			\
-		.function = __func__,				\
-		.filename = __FILE__,				\
+		._modname = KBUILD_MODNAME,			\
+		._function = __func__,				\
+		._filename = __FILE__,				\
 		.format = (fmt),				\
 		.lineno = __LINE__,				\
 		.flags = _DPRINTK_FLAGS_DEFAULT,		\
diff --git a/include/trace/events/dyndbg.h b/include/trace/events/dyndbg.h
index e19fcb56566c..2997289c0e3f 100644
--- a/include/trace/events/dyndbg.h
+++ b/include/trace/events/dyndbg.h
@@ -6,6 +6,7 @@
 #define _TRACE_DYNDBG_H
 
 #include <linux/tracepoint.h>
+#include <linux/dynamic_debug.h>
 
 /* capture pr_debug() callsite descriptor and message */
 TRACE_EVENT(prdbg,
@@ -32,8 +33,7 @@ TRACE_EVENT(prdbg,
 		    __get_str(msg)[len] = 0;
 		    ),
 
-	    TP_printk("%s.%s %s", __entry->desc->modname,
-		      __entry->desc->function, __get_str(msg))
+	    TP_printk("%s", __get_str(msg))
 );
 
 /* capture dev_dbg() callsite descriptor, device, and message */
@@ -64,8 +64,7 @@ TRACE_EVENT(devdbg,
 		    __get_str(msg)[len] = 0;
 		    ),
 
-	    TP_printk("%s.%s %s", __entry->desc->modname,
-		      __entry->desc->function, __get_str(msg))
+	    TP_printk("%s", __get_str(msg))
 );
 
 #endif /* _TRACE_DYNDBG_H */
diff --git a/lib/dynamic_debug.c b/lib/dynamic_debug.c
index 0870e939f255..5a22708679a7 100644
--- a/lib/dynamic_debug.c
+++ b/lib/dynamic_debug.c
@@ -167,6 +167,15 @@ static struct ddebug_class_map *ddebug_find_valid_class(struct ddebug_table cons
 	return NULL;
 }
 
+static inline struct _ddebug_site * _ddebug_map_site(const struct _ddebug *desc)
+{
+	return desc->site;
+}
+#define _desc_field(desc, _fld)	(desc ? (_ddebug_map_site(desc)->_fld) : "_na_")
+#define desc_modname(desc)	_desc_field(desc, _modname)
+#define desc_function(desc)	_desc_field(desc, _function)
+#define desc_filename(desc)	_desc_field(desc, _filename)
+
 #define __outvar /* filled by callee */
 /*
  * Search the tables for _ddebug's which match the given `query' and
@@ -212,16 +221,16 @@ static int ddebug_change(const struct ddebug_query *query,
 
 			/* match against the source filename */
 			if (query->filename &&
-			    !match_wildcard(query->filename, dp->filename) &&
+			    !match_wildcard(query->filename, desc_filename(dp)) &&
 			    !match_wildcard(query->filename,
-					   kbasename(dp->filename)) &&
+					    kbasename(desc_filename(dp))) &&
 			    !match_wildcard(query->filename,
-					   trim_prefix(dp->filename)))
+					    trim_prefix(desc_filename(dp))))
 				continue;
 
 			/* match against the function */
 			if (query->function &&
-			    !match_wildcard(query->function, dp->function))
+			    !match_wildcard(query->function, desc_function(dp)))
 				continue;
 
 			/* match against the format */
@@ -257,9 +266,9 @@ static int ddebug_change(const struct ddebug_query *query,
 				static_branch_enable(&dp->key.dd_key_true);
 			}
 #endif
-			v4pr_info("changed %s:%d [%s]%s %s => %s\n",
-				  trim_prefix(dp->filename), dp->lineno,
-				  dt->mod_name, dp->function,
+			v4pr_info("changed %s:%d [%s]%s %s to %s\n",
+				  trim_prefix(desc_filename(dp)), dp->lineno,
+				  dt->mod_name, desc_function(dp),
 				  ddebug_describe_flags(dp->flags, &fbuf),
 				  ddebug_describe_flags(newflags, &nbuf));
 			dp->flags = newflags;
@@ -836,10 +845,10 @@ static char *__dynamic_emit_prefix(const struct _ddebug *desc, char *buf)
 	pos_after_tid = pos;
 	if (desc->flags & _DPRINTK_FLAGS_INCL_MODNAME)
 		pos += snprintf(buf + pos, remaining(pos), "%s:",
-				desc->modname);
+				desc_modname(desc));
 	if (desc->flags & _DPRINTK_FLAGS_INCL_FUNCNAME)
 		pos += snprintf(buf + pos, remaining(pos), "%s:",
-				desc->function);
+				desc_function(desc));
 	if (desc->flags & _DPRINTK_FLAGS_INCL_LINENO)
 		pos += snprintf(buf + pos, remaining(pos), "%d:",
 				desc->lineno);
@@ -1241,8 +1250,8 @@ static int ddebug_proc_show(struct seq_file *m, void *p)
 	}
 
 	seq_printf(m, "%s:%u [%s]%s =%s \"",
-		   trim_prefix(dp->filename), dp->lineno,
-		   iter->table->mod_name, dp->function,
+		   trim_prefix(desc_filename(dp)), dp->lineno,
+		   iter->table->mod_name, desc_function(dp),
 		   ddebug_describe_flags(dp->flags, &flags));
 	seq_escape_str(m, dp->format, ESCAPE_SPACE, "\t\r\n\"");
 	seq_puts(m, "\"");
@@ -1504,12 +1513,12 @@ static int __init dynamic_debug_init(void)
 	}
 
 	iter = iter_mod_start = __start___dyndbg;
-	modname = iter->modname;
+	modname = iter->_modname;
 	i = mod_sites = mod_ct = 0;
 
 	for (; iter < __stop___dyndbg; iter++, i++, mod_sites++) {
 
-		if (strcmp(modname, iter->modname)) {
+		if (strcmp(modname, iter->_modname)) {
 			mod_ct++;
 			di.num_descs = mod_sites;
 			di.descs = iter_mod_start;
@@ -1518,7 +1527,7 @@ static int __init dynamic_debug_init(void)
 				goto out_err;
 
 			mod_sites = 0;
-			modname = iter->modname;
+			modname = iter->_modname;
 			iter_mod_start = iter;
 		}
 	}
-- 
2.37.2

[PATCH v6 41/57] dyndbg: split repeating columns to new struct _ddebug_site

[Jim Cromie]

Struct _ddebug has 3 RO-data fields: _module, _file, _function, which
have significant repetition in the builtins: 4222 unique records /
8920 callsites on a recent laptop build.  Thats just 47% unique, on
24/56 of the unitary record.

The quick path to excising this redundancy is:
 1- split the table in 2, link 1st to 2nd	(done here)
 2- de-duplicate the 2nd table.			(soon)

So split struct _ddebug, move the 3 fields to a new struct
_ddebug_site, and add a pointer from _ddebug to _debug_sites.  The
lineno field stays in _ddebug, so all _sites in a fn are identical.

The new ptr from _ddebug -> _ddebug_site increases memory footprint,
until step 2 is completed, at which point:

  old = 56	  * 8920
  new = (56-24+8) * 8920 + 24 * 4222
IE:
  DB<2> p 56 * 8920
499520
  DB<3> p 40*8920 + 24 * 4222
458128

Thats 41392 saved, or ~8.3%

Further, the site pointer is just temporary scaffolding:

 - descriptors are in a vector.
 - new desc._idx field (from spare bits) can get us to 0.
   set during _init, not by linker
 - add a header record in front of vector (.gnu.linkonce.dyndbg*)
   point it up to struct dyndbg_info
 - dyndbg_info has .sites
 - same desc._idx gets us sites[._idx]
 - new desc._map field, gives sites[._map]
   this allows de-duplication and packing.

Once that is done, the savings increases:

  DB<7> p  (56 * 8920) - (((56-24) *8920) + 24*4222)
  112752 saved, or 22%

STEP 1:

dynamic_debug.h:

This cuts struct _ddebug in half, renames the top-half to
_ddebug_site, keeps __align(8) for both halves.  Adds a forward decl
for a unified comment for both halves, and added _ddebug.site field to
point at a site record.

Rework DEFINE_DYNAMIC_DEBUG_METADATA_CLS macro to declare & initialize
the 2 static/private struct vars together, and link them together.  It
places each struct into its own section, so the linker packs 2
parallel arrays, and links them like a ladder.

struct _ddebug_info is extended to track _ddebug_site[] just like it
does for _ddebug[] and _ddebug_classes[].

The accessor macros desc_{module,filename,function} follow the
field-moves with added '->site->' references, and return "_nope_" or
"_na_" if the desc or site are null.  This makes those ptrs nullable,
and their referents recoverable (nothing tries to use this yet).
NB: the "_na_" is undone temporarily later, for dev shortcut.

Also add const to lineno field.  It is set by compiler.

In struct ddebug_table, add struct _ddebug_site *sites, to treat new
vector just like the module's _ddebug[]s (its __dyndbg section, for
loadable mods).  While we don't need it now, we will need it to
de-scaffold (drop the _ddebug.site).

dynamic_debug.c:

extern declarations of the section start/end symbols named and
initialized in vmlinux.lds.h

dynamic_debug_init():

Initialize global builtin_state from initialized cursor var.  Trying
to do so statically gave:
   "error: initializer element is not computable at load time"

Check (num-descs == num-sites), and quit early otherwise.  This is an
important precondition, w/o it, we cannot really continue confidently.

I inadvertently created the situation by having __used on 1/2 of the
_ddebug{,_site} pair created by DECLARE_DYNAMIC_DEBUG_METADATA; this
created ~70/ extra site records.  This "worked", but was unnerving
until I tracked it down.

Add site iterator & site_mod_start marker, recapping iter/_mod_start.

Inside the main loop, validate (site == iter->site).  This is the
full/proper precondition for the expected section contents and
inter-linkage; the (num-descs == num-sites) check is just a quick
necessary-but-not-sufficient version of this.

NOTE: this check could be a BUG_ON, esp as any mismatch should have
been caught by the quick-check.  ATM it is just a pr_err; Id prefer to
see errors rather than crashes.

Demotes iter->site by replacing iter->site->_module by site->_module.
This is a small step towards dropping it entirely.

vmlinux.lds.h:

add __dyndbg_sites section and start/end symbols, with the same
align(8) and KEEP as used in the __dyndbg section.

kernel/module/main.c:load_info():

Initialize _ddebug_info.sites with new section address.

Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
---
 include/asm-generic/vmlinux.lds.h |  3 +++
 include/linux/dynamic_debug.h     | 37 +++++++++++++++++++++---------
 kernel/module/main.c              |  2 ++
 lib/dynamic_debug.c               | 38 +++++++++++++++++++++++--------
 4 files changed, 60 insertions(+), 20 deletions(-)

diff --git a/include/asm-generic/vmlinux.lds.h b/include/asm-generic/vmlinux.lds.h
index 9b8bd5504ad9..1e7ee65e8591 100644
--- a/include/asm-generic/vmlinux.lds.h
+++ b/include/asm-generic/vmlinux.lds.h
@@ -351,6 +351,9 @@
 	__start___dyndbg = .;						\
 	KEEP(*(__dyndbg))						\
 	__stop___dyndbg = .;						\
+	__start___dyndbg_sites = .;					\
+	KEEP(*(__dyndbg_sites))						\
+	__stop___dyndbg_sites = .;					\
 	LIKELY_PROFILE()		       				\
 	BRANCH_PROFILE()						\
 	TRACE_PRINTKS()							\
diff --git a/include/linux/dynamic_debug.h b/include/linux/dynamic_debug.h
index e04f5b0a31e2..dcc0e8cc2ef0 100644
--- a/include/linux/dynamic_debug.h
+++ b/include/linux/dynamic_debug.h
@@ -9,20 +9,28 @@
 #include <linux/build_bug.h>
 
 /*
- * An instance of this structure is created in a special
- * ELF section at every dynamic debug callsite.  At runtime,
- * the special section is treated as an array of these.
+ * A pair of these structs are created in 2 special ELF sections
+ * (__dyndbg, __dyndbg_sites) for every dynamic debug callsite.
+ * At runtime, the sections are treated as arrays.
  */
-struct _ddebug {
+struct _ddebug;
+struct _ddebug_site {
 	/*
-	 * These fields are used to drive the user interface
-	 * for selecting and displaying debug callsites.
+	 * These fields (and lineno) are used to:
+	 * - decorate log messages per _ddebug.flags
+	 * - select callsites for modification via >control
+	 * - display callsites & settings in `cat control`
 	 */
 	const char *_modname;
 	const char *_function;
 	const char *_filename;
+} __aligned(8);
+
+struct _ddebug {
+	struct _ddebug_site *site;
+	/* format is always needed, lineno shares word with flags */
 	const char *format;
-	unsigned int lineno:18;
+	const unsigned lineno:18;
 #define CLS_BITS 6
 	unsigned int class_id:CLS_BITS;
 #define _DPRINTK_CLASS_DFLT		((1 << CLS_BITS) - 1)
@@ -58,7 +66,7 @@ struct _ddebug {
 		struct static_key_false dd_key_false;
 	} key;
 #endif
-} __attribute__((aligned(8)));
+} __aligned(8);
 
 enum class_map_type {
 	DD_CLASS_TYPE_DISJOINT_BITS,
@@ -118,8 +126,10 @@ struct ddebug_class_map {
 /* encapsulate linker provided built-in (or module) dyndbg data */
 struct _ddebug_info {
 	struct _ddebug *descs;
+	struct _ddebug_site *sites;
 	struct ddebug_class_map *classes;
 	unsigned int num_descs;
+	unsigned int num_sites;
 	unsigned int num_classes;
 };
 
@@ -137,6 +147,7 @@ struct ddebug_class_param {
 int ddebug_add_module(struct _ddebug_info *dyndbg, const char *modname);
 
 extern int ddebug_remove_module(const char *mod_name);
+
 extern __printf(2, 3)
 void __dynamic_pr_debug(struct _ddebug *descriptor, const char *fmt, ...);
 
@@ -164,11 +175,15 @@ void __dynamic_ibdev_dbg(struct _ddebug *descriptor,
 			 const char *fmt, ...);
 
 #define DEFINE_DYNAMIC_DEBUG_METADATA_CLS(name, cls, fmt)	\
-	static struct _ddebug  __aligned(8)			\
-	__section("__dyndbg") name = {				\
+	static struct _ddebug_site  __aligned(8)		\
+	__section("__dyndbg_sites") name##_site = {		\
 		._modname = KBUILD_MODNAME,			\
-		._function = __func__,				\
 		._filename = __FILE__,				\
+		._function = __func__,				\
+	};							\
+	static struct _ddebug  __aligned(8)			\
+	__section("__dyndbg") name = {				\
+		.site = &name##_site,				\
 		.format = (fmt),				\
 		.lineno = __LINE__,				\
 		.flags = _DPRINTK_FLAGS_DEFAULT,		\
diff --git a/kernel/module/main.c b/kernel/module/main.c
index 6aa6153aa6e0..5a80f18f8e4a 100644
--- a/kernel/module/main.c
+++ b/kernel/module/main.c
@@ -2113,6 +2113,8 @@ static int find_module_sections(struct module *mod, struct load_info *info)
 
 	info->dyndbg.descs = section_objs(info, "__dyndbg",
 					sizeof(*info->dyndbg.descs), &info->dyndbg.num_descs);
+	info->dyndbg.sites = section_objs(info, "__dyndbg_sites",
+					sizeof(*info->dyndbg.sites), &info->dyndbg.num_sites);
 	info->dyndbg.classes = section_objs(info, "__dyndbg_classes",
 					sizeof(*info->dyndbg.classes), &info->dyndbg.num_classes);
 
diff --git a/lib/dynamic_debug.c b/lib/dynamic_debug.c
index 5a22708679a7..f1f354efed5a 100644
--- a/lib/dynamic_debug.c
+++ b/lib/dynamic_debug.c
@@ -44,6 +44,8 @@
 
 extern struct _ddebug __start___dyndbg[];
 extern struct _ddebug __stop___dyndbg[];
+extern struct _ddebug_site __start___dyndbg_sites[];
+extern struct _ddebug_site __stop___dyndbg_sites[];
 extern struct ddebug_class_map __start___dyndbg_classes[];
 extern struct ddebug_class_map __stop___dyndbg_classes[];
 
@@ -52,6 +54,7 @@ struct ddebug_table {
 	const char *mod_name;
 	unsigned int num_ddebugs;
 	struct _ddebug *ddebugs;
+	struct _ddebug_site *sites;
 };
 
 struct ddebug_query {
@@ -1487,20 +1490,27 @@ static int __init dynamic_debug_init_control(void)
 
 	return 0;
 }
+fs_initcall(dynamic_debug_init_control);
+
+static struct _ddebug_info builtin_state;
 
 static int __init dynamic_debug_init(void)
 {
 	struct _ddebug *iter, *iter_mod_start;
+	struct _ddebug_site *site, *site_mod_start;
 	int ret, i, mod_sites, mod_ct;
 	const char *modname;
 	char *cmdline;
 
 	struct _ddebug_info di = {
 		.descs = __start___dyndbg,
+		.sites = __start___dyndbg_sites,
 		.classes = __start___dyndbg_classes,
-		.num_descs = __stop___dyndbg - __start___dyndbg,
-		.num_classes = __stop___dyndbg_classes - __start___dyndbg_classes,
+		.num_descs	= __stop___dyndbg		- __start___dyndbg,
+		.num_sites	= __stop___dyndbg_sites		- __start___dyndbg_sites,
+		.num_classes	= __stop___dyndbg_classes	- __start___dyndbg_classes,
 	};
+	builtin_state = di;
 
 	if (&__start___dyndbg == &__stop___dyndbg) {
 		if (IS_ENABLED(CONFIG_DYNAMIC_DEBUG)) {
@@ -1511,28 +1521,40 @@ static int __init dynamic_debug_init(void)
 		ddebug_init_success = 1;
 		return 0;
 	}
-
+	if (di.num_descs != di.num_sites) {
+		/* cant happen, unless site section has __used, desc does not */
+		pr_err("unequal vectors: descs/sites %d/%d\n", di.num_descs, di.num_sites);
+		return 1;
+	}
 	iter = iter_mod_start = __start___dyndbg;
-	modname = iter->_modname;
+	site = site_mod_start = __start___dyndbg_sites;
+	modname = iter->site->_modname;
 	i = mod_sites = mod_ct = 0;
 
-	for (; iter < __stop___dyndbg; iter++, i++, mod_sites++) {
+	for (; iter < __stop___dyndbg; iter++, site++, i++, mod_sites++) {
+
+		if (site != iter->site)
+			/* XXX: also cant happen, but lets see how it plays */
+			pr_err("linkage problem: site != iter->site\n");
 
-		if (strcmp(modname, iter->_modname)) {
+		if (strcmp(modname, site->_modname)) {
 			mod_ct++;
 			di.num_descs = mod_sites;
 			di.descs = iter_mod_start;
+			di.sites = site_mod_start;
 			ret = __ddebug_add_module(&di, i - mod_sites, modname);
 			if (ret)
 				goto out_err;
 
 			mod_sites = 0;
-			modname = iter->_modname;
+			modname = site->_modname;
 			iter_mod_start = iter;
+			site_mod_start = site;
 		}
 	}
 	di.num_descs = mod_sites;
 	di.descs = iter_mod_start;
+	di.sites = site_mod_start;
 	ret = __ddebug_add_module(&di, i - mod_sites, modname);
 	if (ret)
 		goto out_err;
@@ -1566,5 +1588,3 @@ static int __init dynamic_debug_init(void)
 /* Allow early initialization for boot messages via boot param */
 early_initcall(dynamic_debug_init);
 
-/* Debugfs setup must be done later */
-fs_initcall(dynamic_debug_init_control);
-- 
2.37.2

[PATCH v6 42/57] dyndbg: shrink lineno field by 2 bits

[Jim Cromie]

struct _ddebug.lineno int:18 is bigger than we need:

  git ls-files | grep -P '\.c$' | xargs wc -l | sort -n | tail -n20
  ...
   22553 drivers/scsi/lpfc/lpfc_sli.c
   28593 drivers/net/wireless/broadcom/brcm80211/brcmsmac/phy/phy_n.c
   46300 drivers/net/wireless/realtek/rtw88/rtw8822c_table.c
   48725 drivers/net/wireless/realtek/rtw89/rtw8852a_table.c
 1386670 total
 ...

All but one of the biggest of these are just .data tables, and have no
code, so would never need a pr_debug().  drivers/scsi/lpfc/lpfc_sli.c,
at ~22k lines, would be encodable with 15 bits, but lets just shrink
to 16 bits for now.

RFC: Is this tantamout to a "don't write files with >64kloc" policy ?

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

diff --git a/include/linux/dynamic_debug.h b/include/linux/dynamic_debug.h
index dcc0e8cc2ef0..c05148dab367 100644
--- a/include/linux/dynamic_debug.h
+++ b/include/linux/dynamic_debug.h
@@ -30,7 +30,7 @@ struct _ddebug {
 	struct _ddebug_site *site;
 	/* format is always needed, lineno shares word with flags */
 	const char *format;
-	const unsigned lineno:18;
+	const unsigned lineno:16;
 #define CLS_BITS 6
 	unsigned int class_id:CLS_BITS;
 #define _DPRINTK_CLASS_DFLT		((1 << CLS_BITS) - 1)
-- 
2.37.2

[PATCH v6 43/57] dyndbg: add _index,_map to struct _ddebug

[Jim Cromie]

We now have 2 vectors of data: (__dyndbg, __dyndbg_sites), known to be
equal-length, with _ddebug.site connecting them, like rungs on a
ladder.  In order to drop _ddebug.site, we need to replace the
absolute ptr with a cheap relative-address computation:

   struct _ddebug_site *site = _ddebug_map_site(desc);

1st step: (done here)

add ._index, ._map fields, and initialize them in __debug_add_module()
to N (and = each other), where N is each element's position in the
builtins (or loaded-module).  Then _ddebug_map_site(desc) can compute
&descs[0], and then use container_of() to go up 1 struct.

RFC: Next steps: (outlined here, not done):

1. UPLINK:

Define 2 new header structs, with _uplink fields, pointing at _ddebug_info:

struct _ddebug_site_hdr {
       union {
       	     struct _ddebug_info _uplink*;
	     struct _ddebug_site __;  // sizeof this
	};
};

struct _ddebug_hdr {
       union {
       	     struct _ddebug_info _uplink*;
	     struct _ddebug __;  // sizeof this
	};
};

the union forces the allocation to be the bigger of the 2, with the
expectation that the pointer will always fit.

2. Reserve a record in front of the __dyndbg* sections.

can be done in {module,vmlinux}.lds.h, something like:

SECTIONS {
__dyndbg_sites : ALIGN(8) { *(.gnu.linkonce.dyndbg_site) *(__dyndbg_sites) }
__dyndbg       : ALIGN(8) { *(.gnu.linkonce.dyndbg)      *(__dyndbg) }
}
KEEP( *(.gnu.linkonce.__dyndbg_site) *(__dyndbg_sites))

3. specialize DYNAMIC_DEBUG_METADATA_CLS as DYNAMIC_DEBUG_TABLE.

This special macro version creates header records, and puts them into
.gnu.linkonce section.  Unusually (uniquely?), it is tacitly invoked
by dynamic_debug.h on behalf of all printk.h includers.  This can
result in multiple "declarations" in the same scope, so macro uses
__weak and/or __unused to suppress linkage & errors.

This created mumble-RELATIVE linkage errors in a few parts of the
kernel, I worked around this by just suppressing the declaration if
cflags includes -DDYNDBG_NO_TABLE.

The up-link is init'd in 2 cases:

The file static struct _ddebug_info builtins is initialized by
dynamic_debug_init(), with the 3 ELF sections addresses+lengths
composing the builtin dyndbg-state.  It will be able to also
initialize the header.UPLINK fields, as long as the storage space is
available.  Then rel_map() can rely upon it to provide the &site ref
for a callsite's desc*, if it is enabled.

Then at runtime (assuming initialization is correct):

 - use _index to get &descs[0]
 - container-of gets .UPLINK to &dyndbg_info
 - info->sites[_index]	- replaces .sites
 - info->sites[_map]	- allows de-duplicated vector position. M<N

But thats all talk; this patch just adds and initializes the index and
map fields.

._index:14 allows ~16k entries, more than enough for ~3k built-in
callsites, or ~4k in amdgpu (with dyn-drm-trc commitset).  It is
initialized in __ddebug_add_module(), a new refactorization.

ddebug_add_module() is called from kernel/module.c, that interface is
preserved.  It just passes 0 to inner fn when loading modules.

Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
---
 include/linux/dynamic_debug.h | 3 +++
 lib/dynamic_debug.c           | 8 ++++++++
 2 files changed, 11 insertions(+)

diff --git a/include/linux/dynamic_debug.h b/include/linux/dynamic_debug.h
index c05148dab367..268e903b7c4e 100644
--- a/include/linux/dynamic_debug.h
+++ b/include/linux/dynamic_debug.h
@@ -31,6 +31,8 @@ struct _ddebug {
 	/* format is always needed, lineno shares word with flags */
 	const char *format;
 	const unsigned lineno:16;
+	unsigned _index:14;
+	unsigned _map:14;
 #define CLS_BITS 6
 	unsigned int class_id:CLS_BITS;
 #define _DPRINTK_CLASS_DFLT		((1 << CLS_BITS) - 1)
@@ -60,6 +62,7 @@ struct _ddebug {
 #define _DPRINTK_FLAGS_DEFAULT 0
 #endif
 	unsigned int flags:8;
+
 #ifdef CONFIG_JUMP_LABEL
 	union {
 		struct static_key_true dd_key_true;
diff --git a/lib/dynamic_debug.c b/lib/dynamic_debug.c
index f1f354efed5a..506a7e2e59d6 100644
--- a/lib/dynamic_debug.c
+++ b/lib/dynamic_debug.c
@@ -1344,6 +1344,7 @@ static int __ddebug_add_module(struct _ddebug_info *di, unsigned int base,
 			       const char *modname)
 {
 	struct ddebug_table *dt;
+	int i;
 
 	v3pr_info("add-module: %s.%d sites\n", modname, di->num_descs);
 	if (!di->num_descs) {
@@ -1364,6 +1365,7 @@ static int __ddebug_add_module(struct _ddebug_info *di, unsigned int base,
 	 */
 	dt->mod_name = modname;
 	dt->ddebugs = di->descs;
+	dt->sites = di->sites;
 	dt->num_ddebugs = di->num_descs;
 
 	INIT_LIST_HEAD(&dt->link);
@@ -1372,6 +1374,12 @@ static int __ddebug_add_module(struct _ddebug_info *di, unsigned int base,
 	if (di->classes && di->num_classes)
 		ddebug_attach_module_classes(dt, di->classes, di->num_classes);
 
+	for (i = 0; i < di->num_descs; i++) {
+		di->descs[i]._index = base + i;
+		v3pr_info(" %d %d %s.%s.%d\n", i, base, modname,
+			  di->descs[i].site->_function, di->descs[i].lineno);
+	}
+
 	mutex_lock(&ddebug_lock);
 	list_add_tail(&dt->link, &ddebug_tables);
 	mutex_unlock(&ddebug_lock);
-- 
2.37.2

[PATCH v6 44/57] dyndbg: extend __ddebug_add_module proto to allow packing sites

[Jim Cromie]

In order to actually reclaim useful blocks of memory, we need to
repack the vector of redundant site recs, not just detect the
duplicates.  To allow this, extend __ddebug_add_module()s prototype by
adding:

   struct _ddebug_site *packed_sites - address of empty "stack"
   unsigned int *packed_base - index of Top-of-Stack

This allows dynamic_debug_init() to tell __ddebug_add_module() where
to push the unique site recs it finds while de-duplicating, and to
communicate the new TOS back for the next iteration.

Since we know we are shrinking data, we can overwrite _ddebug_sites[],
for both builtins, and loadable modules, via ddebug_add_module().

For ddebug_add_module(), which is called from kernel/module/main, the
2 args: reuse the module.sites vector, with a 0 offset.  This will
allow de-duplication of the local vector.

No de-duplication is done yet, so no use of the stack.

Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
---
 lib/dynamic_debug.c | 15 ++++++++++-----
 1 file changed, 10 insertions(+), 5 deletions(-)

diff --git a/lib/dynamic_debug.c b/lib/dynamic_debug.c
index 506a7e2e59d6..1b57e43e9c31 100644
--- a/lib/dynamic_debug.c
+++ b/lib/dynamic_debug.c
@@ -1341,7 +1341,8 @@ static void ddebug_attach_module_classes(struct ddebug_table *dt,
  * and add it to the global list.
  */
 static int __ddebug_add_module(struct _ddebug_info *di, unsigned int base,
-			       const char *modname)
+			       const char *modname, struct _ddebug_site *packed_sites,
+			       unsigned int *packed_base)
 {
 	struct ddebug_table *dt;
 	int i;
@@ -1390,7 +1391,8 @@ static int __ddebug_add_module(struct _ddebug_info *di, unsigned int base,
 
 int ddebug_add_module(struct _ddebug_info *di, const char *modname)
 {
-	return __ddebug_add_module(di, 0, modname);
+	unsigned int packed_base = 0;
+	return __ddebug_add_module(di, 0, modname, di->sites, &packed_base);
 }
 
 /* helper for ddebug_dyndbg_(boot|module)_param_cb */
@@ -1506,7 +1508,7 @@ static int __init dynamic_debug_init(void)
 {
 	struct _ddebug *iter, *iter_mod_start;
 	struct _ddebug_site *site, *site_mod_start;
-	int ret, i, mod_sites, mod_ct;
+	int ret, i, mod_sites, mod_ct, site_base;
 	const char *modname;
 	char *cmdline;
 
@@ -1550,7 +1552,8 @@ static int __init dynamic_debug_init(void)
 			di.num_descs = mod_sites;
 			di.descs = iter_mod_start;
 			di.sites = site_mod_start;
-			ret = __ddebug_add_module(&di, i - mod_sites, modname);
+			ret = __ddebug_add_module(&di, i - mod_sites, modname,
+						  __start___dyndbg_sites, &site_base);
 			if (ret)
 				goto out_err;
 
@@ -1563,11 +1566,13 @@ static int __init dynamic_debug_init(void)
 	di.num_descs = mod_sites;
 	di.descs = iter_mod_start;
 	di.sites = site_mod_start;
-	ret = __ddebug_add_module(&di, i - mod_sites, modname);
+	ret = __ddebug_add_module(&di, i - mod_sites, modname,
+				  __start___dyndbg_sites, &site_base);
 	if (ret)
 		goto out_err;
 
 	ddebug_init_success = 1;
+
 	vpr_info("%d prdebugs in %d modules, %d KiB in ddebug tables, %d kiB in __dyndbg section\n",
 		 i, mod_ct, (int)((mod_ct * sizeof(struct ddebug_table)) >> 10),
 		 (int)((i * sizeof(struct _ddebug)) >> 10));
-- 
2.37.2

[PATCH v6 45/57] dyndbg: de-duplicate sites

[Jim Cromie]

In __ddebug_add_module(), detect repeated site records (by function
name changes), and push changes onto the stack/vector passed in
from dynamic_debug_init().

For ddebug_add_module(), this transparently de-duplicates the local
sites vector (passed in recently added stack-base, and offset 0).

Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
---
 lib/dynamic_debug.c | 20 ++++++++++++++------
 1 file changed, 14 insertions(+), 6 deletions(-)

diff --git a/lib/dynamic_debug.c b/lib/dynamic_debug.c
index 1b57e43e9c31..41c23ec979f4 100644
--- a/lib/dynamic_debug.c
+++ b/lib/dynamic_debug.c
@@ -1347,7 +1347,7 @@ static int __ddebug_add_module(struct _ddebug_info *di, unsigned int base,
 	struct ddebug_table *dt;
 	int i;
 
-	v3pr_info("add-module: %s.%d sites\n", modname, di->num_descs);
+	v3pr_info("add-module: %s.%d sites, start: %d\n", modname, di->num_descs, base);
 	if (!di->num_descs) {
 		v3pr_info(" skip %s\n", modname);
 		return 0;
@@ -1376,11 +1376,19 @@ static int __ddebug_add_module(struct _ddebug_info *di, unsigned int base,
 		ddebug_attach_module_classes(dt, di->classes, di->num_classes);
 
 	for (i = 0; i < di->num_descs; i++) {
-		di->descs[i]._index = base + i;
-		v3pr_info(" %d %d %s.%s.%d\n", i, base, modname,
-			  di->descs[i].site->_function, di->descs[i].lineno);
-	}
 
+		if (di->descs[i].site->_function != packed_sites[(*packed_base)]._function)
+			memcpy((void *) &packed_sites[++(*packed_base)],
+			       (void *) di->descs[i].site, sizeof(struct _ddebug_site));
+		else
+			di->descs[i].site = &packed_sites[(*packed_base)];
+
+		di->descs[i]._index = i + base;
+		di->descs[i]._map = *packed_base;
+
+		v3pr_info(" %d %d %s.%s.%d - %d\n", i, *packed_base, modname,
+			  di->descs[i].site->_function, di->descs[i].lineno, *packed_base);
+	}
 	mutex_lock(&ddebug_lock);
 	list_add_tail(&dt->link, &ddebug_tables);
 	mutex_unlock(&ddebug_lock);
@@ -1539,7 +1547,7 @@ static int __init dynamic_debug_init(void)
 	iter = iter_mod_start = __start___dyndbg;
 	site = site_mod_start = __start___dyndbg_sites;
 	modname = iter->site->_modname;
-	i = mod_sites = mod_ct = 0;
+	i = mod_sites = mod_ct = site_base = 0;
 
 	for (; iter < __stop___dyndbg; iter++, site++, i++, mod_sites++) {
 
-- 
2.37.2

[PATCH v6 46/57] dyndbg: drop site-> in add-module, more needed

[Jim Cromie]

---
 lib/dynamic_debug.c | 15 ++++++++-------
 1 file changed, 8 insertions(+), 7 deletions(-)

diff --git a/lib/dynamic_debug.c b/lib/dynamic_debug.c
index 41c23ec979f4..059212df68f9 100644
--- a/lib/dynamic_debug.c
+++ b/lib/dynamic_debug.c
@@ -1347,7 +1347,7 @@ static int __ddebug_add_module(struct _ddebug_info *di, unsigned int base,
 	struct ddebug_table *dt;
 	int i;
 
-	v3pr_info("add-module: %s.%d sites, start: %d\n", modname, di->num_descs, base);
+	v3pr_info("add-module: %s %d/%d sites, start: %d\n", modname, di->num_descs, di->num_sites, base);
 	if (!di->num_descs) {
 		v3pr_info(" skip %s\n", modname);
 		return 0;
@@ -1375,19 +1375,20 @@ static int __ddebug_add_module(struct _ddebug_info *di, unsigned int base,
 	if (di->classes && di->num_classes)
 		ddebug_attach_module_classes(dt, di->classes, di->num_classes);
 
+	//BUG_ON(di->num_descs != di->num_sites);
+
 	for (i = 0; i < di->num_descs; i++) {
 
-		if (di->descs[i].site->_function != packed_sites[(*packed_base)]._function)
+		if (di->sites[i]._function != packed_sites[(*packed_base)]._function)
+
 			memcpy((void *) &packed_sites[++(*packed_base)],
-			       (void *) di->descs[i].site, sizeof(struct _ddebug_site));
-		else
-			di->descs[i].site = &packed_sites[(*packed_base)];
+			       (void *) &di->sites[i], sizeof(struct _ddebug_site));
 
 		di->descs[i]._index = i + base;
 		di->descs[i]._map = *packed_base;
 
-		v3pr_info(" %d %d %s.%s.%d - %d\n", i, *packed_base, modname,
-			  di->descs[i].site->_function, di->descs[i].lineno, *packed_base);
+		v3pr_info(" %d %d %s.%s.%d\n", i, *packed_base, modname,
+			  packed_sites[*packed_base]._function, di->descs[i].lineno);
 	}
 	mutex_lock(&ddebug_lock);
 	list_add_tail(&dt->link, &ddebug_tables);
-- 
2.37.2

[PATCH v6 47/57] dyndbg: demote iter->site in _init

[Jim Cromie]

---
 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 059212df68f9..65b0a1025ddf 100644
--- a/lib/dynamic_debug.c
+++ b/lib/dynamic_debug.c
@@ -1547,7 +1547,7 @@ static int __init dynamic_debug_init(void)
 	}
 	iter = iter_mod_start = __start___dyndbg;
 	site = site_mod_start = __start___dyndbg_sites;
-	modname = iter->site->_modname;
+	modname = site->_modname;
 	i = mod_sites = mod_ct = site_base = 0;
 
 	for (; iter < __stop___dyndbg; iter++, site++, i++, mod_sites++) {
-- 
2.37.2

[PATCH v6 48/57] dyndbg: add .gnu.linkonce slot in vmlinux.lds.h KEEPs

[Jim Cromie]

Add linker symbols and KEEPs for .gnu.linkonce.dyndbg and
.gnu.linkonce.dyndbg_sites sections, placing them in front of their
respective dyndbg and dyndbg_sites sections.

This placement gives us a known relative offset (ie -1) from the start
of the vector to the header, letting us use container_of to get it.
The _index added previously allows determining &descs[0] from any
desc[N].

The .gnu.linkonce. collapses possible multiple declarations into a
single allocation, with a single address.

todo: will need similar for modules.lds.h

Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
---
 include/asm-generic/vmlinux.lds.h | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/include/asm-generic/vmlinux.lds.h b/include/asm-generic/vmlinux.lds.h
index 1e7ee65e8591..20fdea9efd78 100644
--- a/include/asm-generic/vmlinux.lds.h
+++ b/include/asm-generic/vmlinux.lds.h
@@ -348,9 +348,13 @@
 	__start___dyndbg_classes = .;					\
 	KEEP(*(__dyndbg_classes))					\
 	__stop___dyndbg_classes = .;					\
+	__dyndbg_header = .;						\
+	KEEP(*(.gnu.linkonce.dyndbg))					\
 	__start___dyndbg = .;						\
 	KEEP(*(__dyndbg))						\
 	__stop___dyndbg = .;						\
+	__dyndbg_site_header = .;					\
+	KEEP(*(.gnu.linkonce.dyndbg_sites))				\
 	__start___dyndbg_sites = .;					\
 	KEEP(*(__dyndbg_sites))						\
 	__stop___dyndbg_sites = .;					\
-- 
2.37.2

[PATCH v6 49/57] dyndbg: add structs _ddebug_hdr, _ddebug_site_hdr

[Jim Cromie]

Add new structs _ddebug_hdr and _ddebug_site_hdr, latter for symmetry.

The job of the struct _ddebug_hdr is to:

Contain an _uplink member, which points up to the _ddebug_info
record that keeps builtin and module's dyndbg state.  That record is
init'd (by dynamic_debug_init for builtins, or find_module_sections
for loadables).

Be declared in .gnu.linkonce.dyndbg section, which places it just
before the __dyndbg section; a fixed relative offset.

This allows _ddebug_map_site(desc) to cheaply compute
&descs[desc._index], &descs[0], then container_of() to get the header
and its ._uplink, to the _ddebug_info, which gives access to
->sites[desc->_map].

Structurally, the header has a single unnamed union (which exposes its
field names upward) containing an embedded struct _ddebug{,_site}
(this forces the size to be compatible with the array/section its
destined for), shared with our new struct _ddebug_info * _uplink
member, which is also inside an unnamed struct, to allow adding other
fields later to use the remaining space.

In dynamic_debug.c: ref the linker symbols for the headers, print them
to confirm expected linkages; things look proper.  Add a header ref to
struct _ddebug_info, to facilitate the validity checks.

Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
---
 include/linux/dynamic_debug.h | 23 ++++++++++++++++++++++-
 lib/dynamic_debug.c           |  9 +++++++++
 2 files changed, 31 insertions(+), 1 deletion(-)

diff --git a/include/linux/dynamic_debug.h b/include/linux/dynamic_debug.h
index 268e903b7c4e..f23608c38a79 100644
--- a/include/linux/dynamic_debug.h
+++ b/include/linux/dynamic_debug.h
@@ -126,8 +126,29 @@ struct ddebug_class_map {
 #define NUM_TYPE_ARGS(eltype, ...)				\
         (sizeof((eltype[]){__VA_ARGS__}) / sizeof(eltype))
 
-/* encapsulate linker provided built-in (or module) dyndbg data */
+/* define header record, linker inserts it at descs[0] */
+struct _ddebug_hdr {
+	union {
+		struct _ddebug __;  /* force sizeof this */
+		struct {
+			struct _ddebug_info * _uplink;
+			/* space available */
+		};
+	};
+};
+/* here for symmetry, extra storage */
+struct _ddebug_site_hdr {
+	union {
+		struct _ddebug_site __;  /* force sizeof this */
+		struct {
+			struct _ddebug_info  * _uplink;
+		};
+	};
+};
+
+/* encapsulate linker provided built-in (or module) dyndbg vectors */
 struct _ddebug_info {
+	struct _ddebug_hdr *hdr;
 	struct _ddebug *descs;
 	struct _ddebug_site *sites;
 	struct ddebug_class_map *classes;
diff --git a/lib/dynamic_debug.c b/lib/dynamic_debug.c
index 65b0a1025ddf..91fe7fb5dda9 100644
--- a/lib/dynamic_debug.c
+++ b/lib/dynamic_debug.c
@@ -49,6 +49,9 @@ extern struct _ddebug_site __stop___dyndbg_sites[];
 extern struct ddebug_class_map __start___dyndbg_classes[];
 extern struct ddebug_class_map __stop___dyndbg_classes[];
 
+extern struct _ddebug_hdr __dyndbg_header[];
+extern struct _ddebug_site_hdr __dyndbg_site_header[];
+
 struct ddebug_table {
 	struct list_head link, maps;
 	const char *mod_name;
@@ -1522,6 +1525,7 @@ static int __init dynamic_debug_init(void)
 	char *cmdline;
 
 	struct _ddebug_info di = {
+		.hdr = __dyndbg_header,
 		.descs = __start___dyndbg,
 		.sites = __start___dyndbg_sites,
 		.classes = __start___dyndbg_classes,
@@ -1545,6 +1549,11 @@ static int __init dynamic_debug_init(void)
 		pr_err("unequal vectors: descs/sites %d/%d\n", di.num_descs, di.num_sites);
 		return 1;
 	}
+
+	/* these 2 print the same, until _TABLE is added */
+	v2pr_info("%px %px \n", __dyndbg_header, __dyndbg_site_header);
+	v2pr_info("%px %px \n", di.descs, di.sites);
+
 	iter = iter_mod_start = __start___dyndbg;
 	site = site_mod_start = __start___dyndbg_sites;
 	modname = site->_modname;
-- 
2.37.2

[PATCH v6 50/57] dyndbg: count unique callsites

[Jim Cromie]

Count de-duplicated callsites.  Since the _ddebug_site excludes
lineno, all callsites in a function are identical, and this
effectively counts functions in the module with callsites.

Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
---
 lib/dynamic_debug.c | 11 +++++------
 1 file changed, 5 insertions(+), 6 deletions(-)

diff --git a/lib/dynamic_debug.c b/lib/dynamic_debug.c
index 91fe7fb5dda9..891d70d7fed4 100644
--- a/lib/dynamic_debug.c
+++ b/lib/dynamic_debug.c
@@ -1348,7 +1348,7 @@ static int __ddebug_add_module(struct _ddebug_info *di, unsigned int base,
 			       unsigned int *packed_base)
 {
 	struct ddebug_table *dt;
-	int i;
+	int i, num_funcs = 0;
 
 	v3pr_info("add-module: %s %d/%d sites, start: %d\n", modname, di->num_descs, di->num_sites, base);
 	if (!di->num_descs) {
@@ -1381,12 +1381,11 @@ static int __ddebug_add_module(struct _ddebug_info *di, unsigned int base,
 	//BUG_ON(di->num_descs != di->num_sites);
 
 	for (i = 0; i < di->num_descs; i++) {
-
-		if (di->sites[i]._function != packed_sites[(*packed_base)]._function)
-
+		if (di->sites[i]._function != packed_sites[(*packed_base)]._function) {
+			num_funcs++;
 			memcpy((void *) &packed_sites[++(*packed_base)],
 			       (void *) &di->sites[i], sizeof(struct _ddebug_site));
-
+		}
 		di->descs[i]._index = i + base;
 		di->descs[i]._map = *packed_base;
 
@@ -1397,7 +1396,7 @@ static int __ddebug_add_module(struct _ddebug_info *di, unsigned int base,
 	list_add_tail(&dt->link, &ddebug_tables);
 	mutex_unlock(&ddebug_lock);
 
-	vpr_info("%3u debug prints in module %s\n", di->num_descs, modname);
+	vpr_info("%3u debug prints in %d functions, in module %s\n", di->num_descs, num_funcs, modname);
 	return 0;
 }
 
-- 
2.37.2

[PATCH v6 51/57] dyndbg: prevent build bugs via -DNO_DYNAMIC_DEBUG_TABLE

[Jim Cromie]

The next patch adds DEFINE_DYNAMIC_DEBUG_TABLE(), which broke several
subtrees, including efi, vdso, and some of arch/*/boot/compressed,
with various relocation errors, iirc.

Avoid those problems by adding a define to suppress the "transparent"
DEFINE_DYNAMIC_DEBUG_TABLE() invocation.  I found the x86 problems
myself, lkp@intel.com found arm & sparc problems, and may yet find
others.

Reported-by: <lkp@intel.com> # on [jimc:lkp-test/dyndbg-diet] recently
Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
---
 arch/arm/boot/compressed/Makefile     | 2 ++
 arch/sparc/vdso/Makefile              | 2 ++
 arch/x86/boot/compressed/Makefile     | 1 +
 arch/x86/entry/vdso/Makefile          | 3 +++
 arch/x86/purgatory/Makefile           | 1 +
 drivers/firmware/efi/libstub/Makefile | 3 ++-
 6 files changed, 11 insertions(+), 1 deletion(-)

diff --git a/arch/arm/boot/compressed/Makefile b/arch/arm/boot/compressed/Makefile
index 41bcbb460fac..f2d7a3b62727 100644
--- a/arch/arm/boot/compressed/Makefile
+++ b/arch/arm/boot/compressed/Makefile
@@ -81,6 +81,8 @@ compress-$(CONFIG_KERNEL_LZMA) = lzma_with_size
 compress-$(CONFIG_KERNEL_XZ)   = xzkern_with_size
 compress-$(CONFIG_KERNEL_LZ4)  = lz4_with_size
 
+KBUILD_CFLAGS += -DNO_DYNAMIC_DEBUG_TABLE
+
 libfdt_objs := fdt_rw.o fdt_ro.o fdt_wip.o fdt.o
 
 ifeq ($(CONFIG_ARM_ATAG_DTB_COMPAT),y)
diff --git a/arch/sparc/vdso/Makefile b/arch/sparc/vdso/Makefile
index 77d7b9032158..58ed4d64c978 100644
--- a/arch/sparc/vdso/Makefile
+++ b/arch/sparc/vdso/Makefile
@@ -30,6 +30,8 @@ obj-y += $(vdso_img_objs)
 targets += $(vdso_img_cfiles)
 targets += $(vdso_img_sodbg) $(vdso_img-y:%=vdso%.so)
 
+KBUILD_CFLAGS += -DNO_DYNAMIC_DEBUG_TABLE
+
 CPPFLAGS_vdso.lds += -P -C
 
 VDSO_LDFLAGS_vdso.lds = -m elf64_sparc -soname linux-vdso.so.1 --no-undefined \
diff --git a/arch/x86/boot/compressed/Makefile b/arch/x86/boot/compressed/Makefile
index 35ce1a64068b..b76bbf9fc504 100644
--- a/arch/x86/boot/compressed/Makefile
+++ b/arch/x86/boot/compressed/Makefile
@@ -36,6 +36,7 @@ KBUILD_CFLAGS := -m$(BITS) -O2 $(CLANG_FLAGS)
 KBUILD_CFLAGS += -fno-strict-aliasing -fPIE
 KBUILD_CFLAGS += -Wundef
 KBUILD_CFLAGS += -DDISABLE_BRANCH_PROFILING
+KBUILD_CFLAGS += -DNO_DYNAMIC_DEBUG_TABLE
 cflags-$(CONFIG_X86_32) := -march=i386
 cflags-$(CONFIG_X86_64) := -mcmodel=small -mno-red-zone
 KBUILD_CFLAGS += $(cflags-y)
diff --git a/arch/x86/entry/vdso/Makefile b/arch/x86/entry/vdso/Makefile
index 12f6c4d714cd..3182728f9f4d 100644
--- a/arch/x86/entry/vdso/Makefile
+++ b/arch/x86/entry/vdso/Makefile
@@ -29,6 +29,9 @@ vobjs32-y := vdso32/note.o vdso32/system_call.o vdso32/sigreturn.o
 vobjs32-y += vdso32/vclock_gettime.o
 vobjs-$(CONFIG_X86_SGX)	+= vsgx.o
 
+# avoid a x86_64_RELATIVE error
+KBUILD_CFLAGS += -DNO_DYNAMIC_DEBUG_TABLE
+
 # files to link into kernel
 obj-y				+= vma.o extable.o
 KASAN_SANITIZE_vma.o		:= y
diff --git a/arch/x86/purgatory/Makefile b/arch/x86/purgatory/Makefile
index 31c634a22818..8d264836ae64 100644
--- a/arch/x86/purgatory/Makefile
+++ b/arch/x86/purgatory/Makefile
@@ -35,6 +35,7 @@ PURGATORY_CFLAGS_REMOVE := -mcmodel=kernel
 PURGATORY_CFLAGS := -mcmodel=large -ffreestanding -fno-zero-initialized-in-bss -g0
 PURGATORY_CFLAGS += $(DISABLE_STACKLEAK_PLUGIN) -DDISABLE_BRANCH_PROFILING
 PURGATORY_CFLAGS += -fno-stack-protector
+PURGATORY_CFLAGS += -DNO_DYNAMIC_DEBUG_TABLE
 
 # Default KBUILD_CFLAGS can have -pg option set when FTRACE is enabled. That
 # in turn leaves some undefined symbols like __fentry__ in purgatory and not
diff --git a/drivers/firmware/efi/libstub/Makefile b/drivers/firmware/efi/libstub/Makefile
index 3ef67431f05e..2b7e34555c5a 100644
--- a/drivers/firmware/efi/libstub/Makefile
+++ b/drivers/firmware/efi/libstub/Makefile
@@ -14,7 +14,8 @@ cflags-$(CONFIG_X86)		+= -m$(BITS) -D__KERNEL__ \
 				   $(call cc-disable-warning, address-of-packed-member) \
 				   $(call cc-disable-warning, gnu) \
 				   -fno-asynchronous-unwind-tables \
-				   $(CLANG_FLAGS)
+				   $(CLANG_FLAGS) \
+				   -DNO_DYNAMIC_DEBUG_TABLE
 
 # arm64 uses the full KBUILD_CFLAGS so it's necessary to explicitly
 # disable the stackleak plugin
-- 
2.37.2

[PATCH v6 52/57] dyndbg: add DEFINE_DYNAMIC_DEBUG_TABLE, use it tacitly RFC

[Jim Cromie]

This defines a new macro (tbd: tweak name) which is a special version
of DEFINE_DYNAMIC_DEBUG_METADATA_CLS().  Unlike that macro, which
declares callsites in pairs of desc/site recs.

This macro declares a pair of header records, which the linker script
then places once (.gnu.linkonce.) into the front of the respective
sections.  For builtins, the .linkonce gives us a single header
preceding all ~3-5k callsites.

It uses __unused, __weak, .gnu.linkonce to avoid trouble with multiple
inclusions, and should not consume space when not linked to by a
callsite in a loadable module.

Atypically, this macro is also tacitly invoked in the header, which is
indirectly included by printk.h.  This means 2 things: it mostly
insures that source files will declare it at least once, and that
multiple decls resolve to the identical storage address.

I did this with the expectation that I could let the linker compute
the offset and initialize ._index accordingly, but that resulted in
some "linker cant compute" error.  Ive initialized it in
__ddebug_add_module() instead.

Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
---
 include/linux/dynamic_debug.h | 34 ++++++++++++++++++++++++++++++++++
 1 file changed, 34 insertions(+)

diff --git a/include/linux/dynamic_debug.h b/include/linux/dynamic_debug.h
index f23608c38a79..23d3d2882882 100644
--- a/include/linux/dynamic_debug.h
+++ b/include/linux/dynamic_debug.h
@@ -220,6 +220,32 @@ void __dynamic_ibdev_dbg(struct _ddebug *descriptor,
 #define DEFINE_DYNAMIC_DEBUG_METADATA(name, fmt)		\
 	DEFINE_DYNAMIC_DEBUG_METADATA_CLS(name, _DPRINTK_CLASS_DFLT, fmt)
 
+/*
+ * DEFINE_DYNAMIC_DEBUG_TABLE(): This is a special version of
+ * DEFINE_DYNAMIC_DEBUG_METADATA().  It creates a single pair of
+ * header records, which the linker scripts place in front of their
+ * respective sections.
+ *
+ * To allow for a robust runtime test in dynamic_debug_init(), the
+ * pair of records is hardwired into a self-reference loop which can
+ * be validated before the field is altered to support _ddebug_map_site()
+ */
+#define DEFINE_DYNAMIC_DEBUG_TABLE()					\
+	/* forward decl, allowing loopback pointer */			\
+	struct _ddebug_hdr __used __aligned(8)				\
+		__section(".gnu.linkonce.dyndbg")			\
+		_LINKONCE_dyndbg_header;				\
+	struct _ddebug_site_hdr __used __aligned(8)			\
+		__section(".gnu.linkonce.dyndbg_site")			\
+		_LINKONCE_dyndbg_site_header = {			\
+		._uplink = (void *) &_LINKONCE_dyndbg_header		\
+	};								\
+	struct _ddebug_hdr __used __aligned(8)				\
+		__section(".gnu.linkonce.dyndbg")			\
+		_LINKONCE_dyndbg_header = {				\
+		._uplink = (void *) &_LINKONCE_dyndbg_site_header	\
+	}
+
 #ifdef CONFIG_JUMP_LABEL
 
 #ifdef DEBUG
@@ -390,4 +416,12 @@ static inline int param_get_dyndbg_classes(char *buffer, const struct kernel_par
 
 extern const struct kernel_param_ops param_ops_dyndbg_classes;
 
+#if ((defined(CONFIG_DYNAMIC_DEBUG) ||					\
+      (defined(CONFIG_DYNAMIC_DEBUG_CORE) && defined(DYNAMIC_DEBUG_MODULE))) \
+     && defined(KBUILD_MODNAME) && !defined(NO_DYNAMIC_DEBUG_TABLE))
+
+/* transparently invoked, except when -DNO_DYNAMIC_DEBUG_TABLE */
+DEFINE_DYNAMIC_DEBUG_TABLE();
+#endif
+
 #endif
-- 
2.37.2

[PATCH v6 53/57] dyndbg: add/use is_dyndbg_header then set _uplink

[Jim Cromie]

Add static int is_dyndbg_header(d), which verifies that the arg is
initialized as expected; that it points to the _ddebug_hdr &
_ddebug_site_hdr records initialized by DYNAMIC_DEBUG_TABLE().

That init macro sets the _uplink fields in the 2 records to point at
each other.  This is an impossible situation for the regular callsite
record pairs built by *_METADATA_CLS(), so it provides a robust
verification that linkage happened as we require/depend upon.

In dynamic_debug_init(), is_dyndbg_header() validates the header, and
sets _uplink to builtin_state.

Thereafter, ddebug_map_site() can use it, and we can drop the
_ddebug.site member, and shrink the DATA footprint.
---
 include/linux/dynamic_debug.h |  1 +
 lib/dynamic_debug.c           | 38 +++++++++++++++++++++++++++++++++--
 2 files changed, 37 insertions(+), 2 deletions(-)

diff --git a/include/linux/dynamic_debug.h b/include/linux/dynamic_debug.h
index 23d3d2882882..ed3e1e1c08eb 100644
--- a/include/linux/dynamic_debug.h
+++ b/include/linux/dynamic_debug.h
@@ -149,6 +149,7 @@ struct _ddebug_site_hdr {
 /* encapsulate linker provided built-in (or module) dyndbg vectors */
 struct _ddebug_info {
 	struct _ddebug_hdr *hdr;
+	struct _ddebug_site_hdr *site_hdr;
 	struct _ddebug *descs;
 	struct _ddebug_site *sites;
 	struct ddebug_class_map *classes;
diff --git a/lib/dynamic_debug.c b/lib/dynamic_debug.c
index 891d70d7fed4..0a68fbfd8432 100644
--- a/lib/dynamic_debug.c
+++ b/lib/dynamic_debug.c
@@ -1339,6 +1339,25 @@ static void ddebug_attach_module_classes(struct ddebug_table *dt,
 		vpr_info("module:%s attached %d classes\n", dt->mod_name, ct);
 }
 
+/*
+ * detect the hardwired loopback initialized into the header pairs'
+ * _uplink member.  In dynamic_debug_init(), it verifies the presence
+ * of the header, before setting its _uplink to either &builtin_state
+ * or the module's embedded _ddebug_info.  __ddebug_add_module() will
+ * also use it..
+ */
+static int is_dyndbg_header(struct _ddebug_hdr *hdr)
+{
+	struct _ddebug_site_hdr *sp;
+
+	if (!hdr || !hdr->_uplink)
+		return 0;
+
+	sp = (struct _ddebug_site_hdr *) ((struct _ddebug_hdr *)hdr)->_uplink;
+	return hdr == (struct _ddebug_hdr *)
+		((struct _ddebug_site_hdr *)sp)->_uplink;
+}
+
 /*
  * Allocate a new ddebug_table for the given module
  * and add it to the global list.
@@ -1351,6 +1370,15 @@ static int __ddebug_add_module(struct _ddebug_info *di, unsigned int base,
 	int i, num_funcs = 0;
 
 	v3pr_info("add-module: %s %d/%d sites, start: %d\n", modname, di->num_descs, di->num_sites, base);
+
+	if (is_dyndbg_header((struct _ddebug_hdr *)&di->descs[0])) {
+		pr_info("module header\n");
+		di->hdr = (struct _ddebug_hdr *) di->descs;
+		di->descs++;
+		di->sites++;
+		di->num_descs--;
+		di->num_sites--;
+	}
 	if (!di->num_descs) {
 		v3pr_info(" skip %s\n", modname);
 		return 0;
@@ -1525,6 +1553,7 @@ static int __init dynamic_debug_init(void)
 
 	struct _ddebug_info di = {
 		.hdr = __dyndbg_header,
+		.site_hdr = __dyndbg_site_header,
 		.descs = __start___dyndbg,
 		.sites = __start___dyndbg_sites,
 		.classes = __start___dyndbg_classes,
@@ -1548,11 +1577,16 @@ static int __init dynamic_debug_init(void)
 		pr_err("unequal vectors: descs/sites %d/%d\n", di.num_descs, di.num_sites);
 		return 1;
 	}
-
 	/* these 2 print the same, until _TABLE is added */
-	v2pr_info("%px %px \n", __dyndbg_header, __dyndbg_site_header);
+	v2pr_info("%px %px \n", di.hdr, __dyndbg_site_header);
 	v2pr_info("%px %px \n", di.descs, di.sites);
 
+	if (is_dyndbg_header(di.hdr)) {
+		di.hdr->_uplink = &builtin_state;
+	} else {
+		pr_err("missing header records: cannot continue!\n");
+		return 1;
+	}
 	iter = iter_mod_start = __start___dyndbg;
 	site = site_mod_start = __start___dyndbg_sites;
 	modname = site->_modname;
-- 
2.37.2

[PATCH v6 54/57] dyndbg: add .gnu.linkonce. & __dyndbg* sections in module.lds.h

[Jim Cromie]

For a long time now, loadable modules have tacitly linked the __dyndbg
section into the .ko, as is observable in dmesg by enabling module.c's
pr_debugs and loading a module.  Recently, __dyndbg_sites was added,
following the original model.

But now, we need to explicitly name those (__dyndbg, __dyndbg_sites)
sections in order to place new .gnu.linkonce.dyndbg* sections in front
of them.

This gives us the properties we need for _ddebug_map_site() to drop
the _ddebug.site pointer:

   fixed offset from &__dyndbg[N] to &__dyndbg[0]
   container_of gets &header
   header has ptr to __dyndbg_sites[]
   __dyndbg_sites[_map] gives de-duplicated site recs

NOTE

HEAD~1 took headers off front of descs,sites and saved them into
_ddebug_info, this puts the gnu.linkonce.* records into those vectors.

Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
---
 include/asm-generic/module.lds.h | 12 +++++++++++-
 1 file changed, 11 insertions(+), 1 deletion(-)

diff --git a/include/asm-generic/module.lds.h b/include/asm-generic/module.lds.h
index f210d5c1b78b..328c48dfc88c 100644
--- a/include/asm-generic/module.lds.h
+++ b/include/asm-generic/module.lds.h
@@ -4,7 +4,17 @@
 
 /*
  * <asm/module.lds.h> can specify arch-specific sections for linking modules.
- * Empty for the asm-generic header.
+ *
+ * For loadable modules with CONFIG_DYNAMIC_DEBUG, we need to keep the
+ * 2 __dyndbg* ELF sections, which are loaded by module.c
+ *
+ * Pack the 2 __dyndbg* input sections with their respective
+ * .gnu.linkonce. header records into 2 output sections, with those
+ * header records in the 0th element.
  */
+SECTIONS {
+__dyndbg_sites	: ALIGN(8) { *(.gnu.linkonce.dyndbg_site) *(__dyndbg_sites) }
+__dyndbg	: ALIGN(8) { *(.gnu.linkonce.dyndbg)	  *(__dyndbg) }
+}
 
 #endif /* __ASM_GENERIC_MODULE_LDS_H */
-- 
2.37.2

[PATCH v6 55/57] dyndbg: dynamic_debug_sites_reclaim() using free_reserved_page() WAG

[Jim Cromie]

STATUS:

broken with some over-free, punt and comment out late_initcall

Implement dymamic_debug_sites_reclaim(as a late_initcall) to free the
tail~47% of the builtin __dyndbg_sites[] vector back to the buddy
allocator.  Code is copied from mm/init.c:free_initmem(), wo the
poisoning.  Comments cargo culted wo grokking.

v3pr_info:

 dyndbg: freeing range: ffffea00000c5500-ffffea00000c5700, ffffffff83154668-ffffffff8315c480
 dyndbg:      ie range: ffffea00000c5500-ffffea00000c5700, ffffffff83154000-ffffffff8315c000
 dyndbg: freeing page: ffffea00000c5540, ffffffff83155000
 dyndbg: freeing page: ffffea00000c5580, ffffffff83156000
 dyndbg: freeing page: ffffea00000c55c0, ffffffff83157000
 dyndbg: freeing page: ffffea00000c5600, ffffffff83158000
 dyndbg: freeing page: ffffea00000c5640, ffffffff83159000
 dyndbg: freeing page: ffffea00000c5680, ffffffff8315a000
 dyndbg: freeing page: ffffea00000c56c0, ffffffff8315b000

Presuming those are 4k pages, 28kb is reclaimed, which is reasonably
consistent with the numbers below; 1532/2761 compresson of 64KiB.

I have fixed one edge-case over-free, which gave me a coredump on
```cat control```, there may be (one) other.

 dyndbg: 2762 prdebugs in 235 modules, 11 KiB in ddebug tables, 86 KiB \
 in __dyndbg section, 64 KiB in __dyndbg_sites section

CC: david@redhat.com	# free_reserved_page() tip
Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
---
 lib/dynamic_debug.c | 45 ++++++++++++++++++++++++++++++++++++++++++---
 1 file changed, 42 insertions(+), 3 deletions(-)

diff --git a/lib/dynamic_debug.c b/lib/dynamic_debug.c
index 0a68fbfd8432..194367bc13fb 100644
--- a/lib/dynamic_debug.c
+++ b/lib/dynamic_debug.c
@@ -1542,6 +1542,7 @@ static int __init dynamic_debug_init_control(void)
 fs_initcall(dynamic_debug_init_control);
 
 static struct _ddebug_info builtin_state;
+static __initdata struct _ddebug_site *last_site;
 
 static int __init dynamic_debug_init(void)
 {
@@ -1622,11 +1623,12 @@ static int __init dynamic_debug_init(void)
 	if (ret)
 		goto out_err;
 
+	last_site = &__start___dyndbg_sites[site_base];
 	ddebug_init_success = 1;
 
-	vpr_info("%d prdebugs in %d modules, %d KiB in ddebug tables, %d kiB in __dyndbg section\n",
-		 i, mod_ct, (int)((mod_ct * sizeof(struct ddebug_table)) >> 10),
-		 (int)((i * sizeof(struct _ddebug)) >> 10));
+	vpr_info("%d prdebugs in %d functions, %d modules, %d KiB in ddebug tables, %d,%d kiB in __dyndbg,_sites sections\n",
+		 i, site_base, mod_ct, (int)((mod_ct * sizeof(struct ddebug_table)) >> 10),
+		 (int)((i * sizeof(struct _ddebug)) >> 10), (int)((site_base * sizeof(struct _ddebug_site)) >> 10));
 
 	if (di.num_classes)
 		v2pr_info("  %d builtin ddebug class-maps\n", di.num_classes);
@@ -1652,3 +1654,40 @@ static int __init dynamic_debug_init(void)
 /* Allow early initialization for boot messages via boot param */
 early_initcall(dynamic_debug_init);
 
+static int __init dynamic_debug_sites_reclaim(void)
+{
+	unsigned long addr, end, start;
+	/*
+	 * from mm/init.c:free_initmem (void) wo poisoning
+	 * The init section is aligned to 8k in vmlinux.lds.
+	 * Page align for >8k pagesizes.
+	 */
+	start = (unsigned long)__start___dyndbg_sites;
+	end = (unsigned long)__stop___dyndbg_sites;
+	addr = (unsigned long)last_site;
+
+	vpr_info("full    range: %px-%px, %lx-%lx\n",
+		 virt_to_page(start), virt_to_page(end), start, end);
+
+	vpr_info("freeing range: %px-%px, %lx-%lx\n",
+		 virt_to_page(addr), virt_to_page(end), addr, end);
+
+	addr &= PAGE_MASK;
+	addr += PAGE_SIZE;
+	end &= PAGE_MASK;
+	end += PAGE_SIZE;
+
+	vpr_info("ie      range: %px-%px, %lx-%lx\n",
+		 virt_to_page(addr), virt_to_page(end), addr, end);
+
+	if (verbose < 2) {
+		vpr_info(" skipping reclaim cuz its broken by `cat control`\n");
+		return 0;
+	}
+	for (; addr < end; addr += PAGE_SIZE) {
+		vpr_info("freeing page: %px, %lx\n", virt_to_page(addr), addr);
+		free_reserved_page(virt_to_page(addr));
+	}
+	return 0;
+}
+//late_initcall(dynamic_debug_sites_reclaim);
-- 
2.37.2

[PATCH v6 56/57] dyndbg: work ddebug_map_site

[Jim Cromie]

attempt container-of, broken, missing use of uplink... took that out.

ptr computations are naive, and wrong.

Deeper prob is lack of _ddebug_vec, with header and descs in same struct.
maybe.

builtin_state looks right in debugger
---
 lib/dynamic_debug.c | 21 +++++++++++++++++++--
 1 file changed, 19 insertions(+), 2 deletions(-)

diff --git a/lib/dynamic_debug.c b/lib/dynamic_debug.c
index 194367bc13fb..11fea1f818a7 100644
--- a/lib/dynamic_debug.c
+++ b/lib/dynamic_debug.c
@@ -173,8 +173,25 @@ static struct ddebug_class_map *ddebug_find_valid_class(struct ddebug_table cons
 	return NULL;
 }
 
-static inline struct _ddebug_site * _ddebug_map_site(const struct _ddebug *desc)
+/*
+ * mapping from desc to site is multi-step:
+ * - _index back to &descs[0]
+ * - container-of to get header struct above
+ * - ._uplink field, pointing to _ddebug_info (for builtins, loadables)
+ * - di->sites[desc->_map]
+ */
+static struct _ddebug_site * _ddebug_map_site(const struct _ddebug *desc)
 {
+	struct _ddebug_info *di;
+	struct _ddebug const *d0 = desc - desc->_index * sizeof(struct _ddebug);
+
+	di = (struct _ddebug_info *) d0;
+
+	v3pr_info("map_site idx:%d map:%d %s.%s  di:%px site:%px ds:%px\n",
+		  desc->_index, desc->_map,
+		  desc->site->_modname, desc->site->_function,
+		  di, desc->site, &di->sites[desc->_map]);
+
 	return desc->site;
 }
 #define _desc_field(desc, _fld)	(desc ? (_ddebug_map_site(desc)->_fld) : "_na_")
@@ -866,7 +883,7 @@ static char *__dynamic_emit_prefix(const struct _ddebug *desc, char *buf)
 	return buf;
 }
 
-static inline char *dynamic_emit_prefix(struct _ddebug *desc, char *buf)
+char *dynamic_emit_prefix(struct _ddebug *desc, char *buf)
 {
 	if (unlikely(desc->flags & _DPRINTK_FLAGS_INCL_ANY))
 		return __dynamic_emit_prefix(desc, buf);
-- 
2.37.2

[PATCH v6 57/57] dyndbg: fiddle with readback value on LEVEL_NAMES types

[Jim Cromie]

my test scripts were writing one val, reading back val+1

  echo L3 > p_level_names
  cat p_level_names
  L4

fix this w a -1 offset.

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

diff --git a/lib/dynamic_debug.c b/lib/dynamic_debug.c
index 11fea1f818a7..7d458601a61b 100644
--- a/lib/dynamic_debug.c
+++ b/lib/dynamic_debug.c
@@ -830,6 +830,8 @@ int param_get_dyndbg_classes(char *buffer, const struct kernel_param *kp)
 		return scnprintf(buffer, PAGE_SIZE, "0x%lx\n", *dcp->bits);
 
 	case DD_CLASS_TYPE_LEVEL_NAMES:
+		return scnprintf(buffer, PAGE_SIZE, "%d\n", *dcp->lvl - 1);
+
 	case DD_CLASS_TYPE_LEVEL_NUM:
 		return scnprintf(buffer, PAGE_SIZE, "%d\n", *dcp->lvl);
 	default:
-- 
2.37.2

Re: [PATCH v6 22/57] drm_print: condense enum drm_debug_category

[Daniel Vetter]

On Sun, Sep 04, 2022 at 03:40:59PM -0600, Jim Cromie wrote:
> enum drm_debug_category has 10 categories, but is initialized with
> bitmasks which require 10 bits of underlying storage.  By using
> natural enumeration, and moving the BIT(cat) into drm_debug_enabled(),
> the enum fits in 4 bits, allowing the category to be represented
> directly in pr_debug callsites, via the ddebug.class_id field.
> 
> While this slightly pessimizes the bit-test in drm_debug_enabled(),
> using dyndbg with JUMP_LABEL will avoid the function entirely.
> 
> NOTE: this change forecloses the possibility of doing:
> 
>   drm_dbg(DRM_UT_CORE|DRM_UT_KMS, "weird 2-cat experiment")
> 
> but thats already strongly implied by the use of the enum itself; its
> not a normal enum if it can be 2 values simultaneously.
> 
> Signed-off-by: Jim Cromie <jim.cromie@gmail.com>

Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>

I guess this would also be a good patch to apply already, so we reduce the
patch set size somewhat?
-Daniel

> ---
>  include/drm/drm_print.h | 22 +++++++++++-----------
>  1 file changed, 11 insertions(+), 11 deletions(-)
> 
> diff --git a/include/drm/drm_print.h b/include/drm/drm_print.h
> index 22fabdeed297..b3b470440e46 100644
> --- a/include/drm/drm_print.h
> +++ b/include/drm/drm_print.h
> @@ -279,49 +279,49 @@ enum drm_debug_category {
>  	 * @DRM_UT_CORE: Used in the generic drm code: drm_ioctl.c, drm_mm.c,
>  	 * drm_memory.c, ...
>  	 */
> -	DRM_UT_CORE		= 0x01,
> +	DRM_UT_CORE,
>  	/**
>  	 * @DRM_UT_DRIVER: Used in the vendor specific part of the driver: i915,
>  	 * radeon, ... macro.
>  	 */
> -	DRM_UT_DRIVER		= 0x02,
> +	DRM_UT_DRIVER,
>  	/**
>  	 * @DRM_UT_KMS: Used in the modesetting code.
>  	 */
> -	DRM_UT_KMS		= 0x04,
> +	DRM_UT_KMS,
>  	/**
>  	 * @DRM_UT_PRIME: Used in the prime code.
>  	 */
> -	DRM_UT_PRIME		= 0x08,
> +	DRM_UT_PRIME,
>  	/**
>  	 * @DRM_UT_ATOMIC: Used in the atomic code.
>  	 */
> -	DRM_UT_ATOMIC		= 0x10,
> +	DRM_UT_ATOMIC,
>  	/**
>  	 * @DRM_UT_VBL: Used for verbose debug message in the vblank code.
>  	 */
> -	DRM_UT_VBL		= 0x20,
> +	DRM_UT_VBL,
>  	/**
>  	 * @DRM_UT_STATE: Used for verbose atomic state debugging.
>  	 */
> -	DRM_UT_STATE		= 0x40,
> +	DRM_UT_STATE,
>  	/**
>  	 * @DRM_UT_LEASE: Used in the lease code.
>  	 */
> -	DRM_UT_LEASE		= 0x80,
> +	DRM_UT_LEASE,
>  	/**
>  	 * @DRM_UT_DP: Used in the DP code.
>  	 */
> -	DRM_UT_DP		= 0x100,
> +	DRM_UT_DP,
>  	/**
>  	 * @DRM_UT_DRMRES: Used in the drm managed resources code.
>  	 */
> -	DRM_UT_DRMRES		= 0x200,
> +	DRM_UT_DRMRES
>  };
>  
>  static inline bool drm_debug_enabled(enum drm_debug_category category)
>  {
> -	return unlikely(__drm_debug & category);
> +	return unlikely(__drm_debug & BIT(category));
>  }
>  
>  /*
> -- 
> 2.37.2
> 

-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch

Re: [PATCH v6 23/57] drm: POC drm on dyndbg - use in core, 2 helpers, 3 drivers.

[Daniel Vetter]

On Sun, Sep 04, 2022 at 03:41:00PM -0600, Jim Cromie wrote:
> Use DECLARE_DYNDBG_CLASSMAP across DRM:
> 
>  - in .c files, since macro defines/initializes a record
> 
>  - in drivers, $mod_{drv,drm,param}.c
>    ie where param setup is done, since a classmap is param related
> 
>  - in drm/drm_print.c
>    since existing __drm_debug param is defined there,
>    and we ifdef it, and provide an elaborated alternative.
> 
>  - in drm_*_helper modules:
>    dp/drm_dp - 1st item in makefile target
>    drivers/gpu/drm/drm_crtc_helper.c - random pick iirc.
> 
> Since these modules all use identical CLASSMAP declarations (ie: names
> and .class_id's) they will all respond together to "class DRM_UT_*"
> query-commands:
> 
>   :#> echo class DRM_UT_KMS +p > /proc/dynamic_debug/control
> 
> NOTES:
> 
> This changes __drm_debug from int to ulong, so BIT() is usable on it.
> 
> DRM's enum drm_debug_category values need to sync with the index of
> their respective class-names here.  Then .class_id == category, and
> dyndbg's class FOO mechanisms will enable drm_dbg(DRM_UT_KMS, ...).
> 
> Though DRM needs consistent categories across all modules, thats not
> generally needed; modules X and Y could define FOO differently (ie a
> different NAME => class_id mapping), changes are made according to
> each module's private class-map.
> 
> No callsites are actually selected by this patch, since none are
> class'd yet.
> 
> Signed-off-by: Jim Cromie <jim.cromie@gmail.com>

So maybe I should just try, but what happens if a drm module doesn't have
these classbits declared? You simply have to use the raw number instead?

> ---
>  drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c | 14 +++++++++++++
>  drivers/gpu/drm/display/drm_dp_helper.c | 13 ++++++++++++
>  drivers/gpu/drm/drm_crtc_helper.c       | 13 ++++++++++++
>  drivers/gpu/drm/drm_print.c             | 27 +++++++++++++++++++++++--
>  drivers/gpu/drm/i915/i915_params.c      | 12 +++++++++++
>  drivers/gpu/drm/nouveau/nouveau_drm.c   | 13 ++++++++++++
>  include/drm/drm_print.h                 |  3 ++-
>  7 files changed, 92 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c
> index de7144b06e93..97e184f44a52 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c
> @@ -38,6 +38,8 @@
>  #include <linux/mmu_notifier.h>
>  #include <linux/suspend.h>
>  #include <linux/cc_platform.h>
> +#include <linux/fb.h>
> +#include <linux/dynamic_debug.h>
>  
>  #include "amdgpu.h"
>  #include "amdgpu_irq.h"
> @@ -185,6 +187,18 @@ int amdgpu_vcnfw_log;
>  
>  static void amdgpu_drv_delayed_reset_work_handler(struct work_struct *work);
>  
> +DECLARE_DYNDBG_CLASSMAP(drm_debug_classes, DD_CLASS_TYPE_DISJOINT_BITS, 0,

Iirc we've talked about maybe some kbuild trickery so that any module
under drivers/gpu/drm gets these by default. I don't think we need to have
this for the first cut, but a macro to avoid the copypaste mistakes would
be really good here.

> +			"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");
> +
>  struct amdgpu_mgpu_info mgpu_info = {
>  	.mutex = __MUTEX_INITIALIZER(mgpu_info.mutex),
>  	.delayed_reset_work = __DELAYED_WORK_INITIALIZER(
> diff --git a/drivers/gpu/drm/display/drm_dp_helper.c b/drivers/gpu/drm/display/drm_dp_helper.c
> index 92990a3d577a..cbb9c4d6d8f2 100644
> --- a/drivers/gpu/drm/display/drm_dp_helper.c
> +++ b/drivers/gpu/drm/display/drm_dp_helper.c
> @@ -30,6 +30,7 @@
>  #include <linux/sched.h>
>  #include <linux/seq_file.h>
>  #include <linux/string_helpers.h>
> +#include <linux/dynamic_debug.h>
>  
>  #include <drm/display/drm_dp_helper.h>
>  #include <drm/display/drm_dp_mst_helper.h>
> @@ -40,6 +41,18 @@
>  
>  #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");
> +
>  struct dp_aux_backlight {
>  	struct backlight_device *base;
>  	struct drm_dp_aux *aux;
> diff --git a/drivers/gpu/drm/drm_crtc_helper.c b/drivers/gpu/drm/drm_crtc_helper.c
> index 457448cc60f7..7d86020b5244 100644
> --- a/drivers/gpu/drm/drm_crtc_helper.c
> +++ b/drivers/gpu/drm/drm_crtc_helper.c
> @@ -32,6 +32,7 @@
>  #include <linux/export.h>
>  #include <linux/kernel.h>
>  #include <linux/moduleparam.h>
> +#include <linux/dynamic_debug.h>
>  
>  #include <drm/drm_atomic.h>
>  #include <drm/drm_atomic_helper.h>
> @@ -50,6 +51,18 @@
>  
>  #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");
> +
>  /**
>   * DOC: overview
>   *
> diff --git a/drivers/gpu/drm/drm_print.c b/drivers/gpu/drm/drm_print.c
> index f783d4963d4b..ec32df35a3e3 100644
> --- a/drivers/gpu/drm/drm_print.c
> +++ b/drivers/gpu/drm/drm_print.c
> @@ -40,7 +40,7 @@
>   * __drm_debug: Enable debug output.
>   * Bitmask of DRM_UT_x. See include/drm/drm_print.h for details.
>   */
> -unsigned int __drm_debug;
> +unsigned long __drm_debug;
>  EXPORT_SYMBOL(__drm_debug);
>  
>  MODULE_PARM_DESC(debug, "Enable debug output, where each bit enables a debug category.\n"
> @@ -52,7 +52,30 @@ MODULE_PARM_DESC(debug, "Enable debug output, where each bit enables a debug cat
>  "\t\tBit 5 (0x20)  will enable VBL messages (vblank code)\n"
>  "\t\tBit 7 (0x80)  will enable LEASE messages (leasing code)\n"
>  "\t\tBit 8 (0x100) will enable DP messages (displayport code)");
> -module_param_named(debug, __drm_debug, int, 0600);
> +
> +#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");
> +
> +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);
> +#endif
>  
>  void __drm_puts_coredump(struct drm_printer *p, const char *str)
>  {
> diff --git a/drivers/gpu/drm/i915/i915_params.c b/drivers/gpu/drm/i915/i915_params.c
> index 6fc475a5db61..d1e4d528cb17 100644
> --- a/drivers/gpu/drm/i915/i915_params.c
> +++ b/drivers/gpu/drm/i915/i915_params.c
> @@ -29,6 +29,18 @@
>  #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");
> +
>  #define i915_param_named(name, T, perm, desc) \
>  	module_param_named(name, i915_modparams.name, T, perm); \
>  	MODULE_PARM_DESC(name, desc)
> diff --git a/drivers/gpu/drm/nouveau/nouveau_drm.c b/drivers/gpu/drm/nouveau/nouveau_drm.c
> index 561309d447e0..fd99ec0f4257 100644
> --- a/drivers/gpu/drm/nouveau/nouveau_drm.c
> +++ b/drivers/gpu/drm/nouveau/nouveau_drm.c
> @@ -28,6 +28,7 @@
>  #include <linux/pm_runtime.h>
>  #include <linux/vga_switcheroo.h>
>  #include <linux/mmu_notifier.h>
> +#include <linux/dynamic_debug.h>
>  
>  #include <drm/drm_aperture.h>
>  #include <drm/drm_crtc_helper.h>
> @@ -70,6 +71,18 @@
>  #include "nouveau_svm.h"
>  #include "nouveau_dmem.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");
> +
>  MODULE_PARM_DESC(config, "option string to pass to driver core");
>  static char *nouveau_config;
>  module_param_named(config, nouveau_config, charp, 0400);
> diff --git a/include/drm/drm_print.h b/include/drm/drm_print.h
> index b3b470440e46..668273e36c2c 100644
> --- a/include/drm/drm_print.h
> +++ b/include/drm/drm_print.h
> @@ -35,7 +35,7 @@
>  #include <drm/drm.h>
>  
>  /* Do *not* use outside of drm_print.[ch]! */
> -extern unsigned int __drm_debug;
> +extern unsigned long __drm_debug;
>  
>  /**
>   * DOC: print
> @@ -275,6 +275,7 @@ static inline struct drm_printer drm_err_printer(const char *prefix)
>   *
>   */
>  enum drm_debug_category {
> +	/* These names must match those in DYNAMIC_DEBUG_CLASSBITS */

I'd just put this into the kerneldoc, then you can also link to the
DRM_PRINT_DECLARE_DEBUG_CLASSBITS macro or whatever you'll call the thing
so drivers don't have to copypaste it all.
-Daniel

>  	/**
>  	 * @DRM_UT_CORE: Used in the generic drm code: drm_ioctl.c, drm_mm.c,
>  	 * drm_memory.c, ...
> -- 
> 2.37.2
> 

-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch

Re: [PATCH v6 28/57] drm_print: refine drm_debug_enabled for jump-label

[Daniel Vetter]

On Sun, Sep 04, 2022 at 03:41:05PM -0600, Jim Cromie wrote:
> In order to use dynamic-debug's jump-label optimization in drm-debug,
> its clarifying to refine drm_debug_enabled into 3 uses:
> 
> 1.   drm_debug_enabled - legacy, public
> 2. __drm_debug_enabled - optimized for dyndbg jump-label enablement.
> 3.  _drm_debug_enabled - pr_debug instrumented, observable
> 
> 1. The legacy version always checks the bits.
> 
> 2. is privileged, for use by __drm_dbg(), __drm_dev_dbg(), which do an
> early return unless the category is enabled.  For dyndbg builds, debug
> callsites are selectively "pre-enabled", so __drm_debug_enabled()
> short-circuits to true there.  Remaining callers of 1 may be able to
> use 2, case by case.
> 
> 3. is 1st wrapped in a macro, with a pr_debug, which reports each
> usage in /proc/dynamic_debug/control, making it observable in the
> logs.  The macro lets the pr_debug see the real caller, not an inline
> function.
> 
> When plugged into 1, 3 identified ~10 remaining callers of the
> function, leading to the follow-on cleanup patch, and would allow
> activating the pr_debugs, estimating the callrate, and the potential
> savings by using the wrapper macro.  It is unused ATM, but it fills
> out the picture.
> 
> Signed-off-by: Jim Cromie <jim.cromie@gmail.com>

So instead of having 3 here as a "you need to hack it in to see what
should be converted" I have a bit a different idea: Could we make the
public version also a dyndbg callsite (like the printing wrappers), but
instead of a dynamic call we'd have a dynamically fixed value we get out?
I think that would take care of everything you have here as an open.

Otherwise I'd just drop 3 for the series we're going to merge.
-Daniel

> ---
>  drivers/gpu/drm/drm_print.c |  4 ++--
>  include/drm/drm_print.h     | 28 ++++++++++++++++++++++++++++
>  2 files changed, 30 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/gpu/drm/drm_print.c b/drivers/gpu/drm/drm_print.c
> index 29a29949ad0b..cb203d63b286 100644
> --- a/drivers/gpu/drm/drm_print.c
> +++ b/drivers/gpu/drm/drm_print.c
> @@ -285,7 +285,7 @@ void __drm_dev_dbg(const struct device *dev, enum drm_debug_category category,
>  	struct va_format vaf;
>  	va_list args;
>  
> -	if (!drm_debug_enabled(category))
> +	if (!__drm_debug_enabled(category))
>  		return;
>  
>  	va_start(args, format);
> @@ -308,7 +308,7 @@ void ___drm_dbg(enum drm_debug_category category, const char *format, ...)
>  	struct va_format vaf;
>  	va_list args;
>  
> -	if (!drm_debug_enabled(category))
> +	if (!__drm_debug_enabled(category))
>  		return;
>  
>  	va_start(args, format);
> diff --git a/include/drm/drm_print.h b/include/drm/drm_print.h
> index dfdd81c3287c..7631b5fb669e 100644
> --- a/include/drm/drm_print.h
> +++ b/include/drm/drm_print.h
> @@ -321,11 +321,39 @@ enum drm_debug_category {
>  	DRM_UT_DRMRES
>  };
>  
> +/*
> + * 3 name flavors of drm_debug_enabled:
> + *   drm_debug_enabled - public/legacy, always checks bits
> + *  _drm_debug_enabled - instrumented to observe call-rates, est overheads.
> + * __drm_debug_enabled - privileged - knows jump-label state, can short-circuit
> + */
>  static inline bool drm_debug_enabled(enum drm_debug_category category)
>  {
>  	return unlikely(__drm_debug & BIT(category));
>  }
>  
> +/*
> + * Wrap fn in macro, so that the pr_debug sees the actual caller, not
> + * the inline fn.  Using this name creates a callsite entry / control
> + * point in /proc/dynamic_debug/control.
> + */
> +#define _drm_debug_enabled(category)				\
> +	({							\
> +		pr_debug("todo: maybe avoid via dyndbg\n");     \
> +		drm_debug_enabled(category);			\
> +	})
> +
> +#if defined(CONFIG_DRM_USE_DYNAMIC_DEBUG)
> +/*
> + * dyndbg is wrapping the drm.debug API, so as to avoid the runtime
> + * bit-test overheads of drm_debug_enabled() in those api calls.
> + * In this case, executed callsites are known enabled, so true.
> + */
> +#define __drm_debug_enabled(category)	true
> +#else
> +#define __drm_debug_enabled(category)	drm_debug_enabled(category)
> +#endif
> +
>  /*
>   * struct device based logging
>   *
> -- 
> 2.37.2
> 

-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch

Re: [PATCH v6 39/57] dyndbg/drm: POC add tracebits sysfs-knob

[Daniel Vetter]

On Sun, Sep 04, 2022 at 03:41:16PM -0600, Jim Cromie wrote:
> clone DRM.debug interface to DRM.tracebits: ie map bits to
> drm-debug-categories, except this interface enables messages to
> tracefs, not to syslog.
> 
> 1- we reuse the class-map added previously.
>    this reflects the single source of both syslog/trace events
> 
> 2- add a 2nd struct ddebug_classes_bitmap_param
>    refs 1, reusing it.
>    flags = "T", to enable trace-events on this callsite.
> 
> 3- module_param_cb([2]) - does the sysfs part
> 
> Signed-off-by: Jim Cromie <jim.cromie@gmail.com>

All the drm patches (excluding nouveau) I haven't commented on:

Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>

I think nouveau I'll leave up to nouveau folks.
-Daniel



> ---
>  drivers/gpu/drm/drm_print.c | 10 ++++++++++
>  1 file changed, 10 insertions(+)
> 
> diff --git a/drivers/gpu/drm/drm_print.c b/drivers/gpu/drm/drm_print.c
> index c50edbf443d3..75d0cecd7e86 100644
> --- a/drivers/gpu/drm/drm_print.c
> +++ b/drivers/gpu/drm/drm_print.c
> @@ -45,6 +45,9 @@
>  unsigned long __drm_debug;
>  EXPORT_SYMBOL(__drm_debug);
>  
> +unsigned long __drm_trace;
> +EXPORT_SYMBOL(__drm_trace);
> +
>  MODULE_PARM_DESC(debug, "Enable debug output, where each bit enables a debug category.\n"
>  "\t\tBit 0 (0x01)  will enable CORE messages (drm core code)\n"
>  "\t\tBit 1 (0x02)  will enable DRIVER messages (drm controller code)\n"
> @@ -77,6 +80,13 @@ static struct ddebug_class_param drm_debug_bitmap = {
>  	.map = &drm_debug_classes,
>  };
>  module_param_cb(debug, &param_ops_dyndbg_classes, &drm_debug_bitmap, 0600);
> +
> +static struct ddebug_class_param drm_trace_bitmap = {
> +	.bits = &__drm_trace,
> +	.flags = "T",
> +	.map = &drm_debug_classes,
> +};
> +module_param_cb(tracecats, &param_ops_dyndbg_classes, &drm_trace_bitmap, 0600);
>  #endif
>  
>  void __drm_puts_coredump(struct drm_printer *p, const char *str)
> -- 
> 2.37.2
> 

-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch

Re: [PATCH v6 10/57] dyndbg: cleanup auto vars in dynamic_debug_init

[Jason Baron]

On 9/4/22 17:40, Jim Cromie wrote:
> rework var-names for clarity, regularity
> rename variables
>   - n to mod_sites - it counts sites-per-module
>   - entries to i - display only
>   - iter_start to iter_mod_start - marks start of each module's subrange
>   - modct to mod_ct - stylistic
> 
> new iterator var:
>   - site - cursor parallel to iter
>     1st step towards 'demotion' of iter->site, for removal later
> 
> treat vars as iters:
>   - drop init at top
>     init just above for-loop, in a textual block
> 
> Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
> ---
>  lib/dynamic_debug.c | 33 +++++++++++++++++----------------
>  1 file changed, 17 insertions(+), 16 deletions(-)
> 
> diff --git a/lib/dynamic_debug.c b/lib/dynamic_debug.c
> index e96dc216463b..2e8ebef3bd0d 100644
> --- a/lib/dynamic_debug.c
> +++ b/lib/dynamic_debug.c
> @@ -1059,11 +1059,10 @@ static int __init dynamic_debug_init_control(void)
>  
>  static int __init dynamic_debug_init(void)
>  {
> -	struct _ddebug *iter, *iter_start;
> -	const char *modname = NULL;
> +	struct _ddebug *iter, *iter_mod_start;
> +	int ret, i, mod_sites, mod_ct;
> +	const char *modname;
>  	char *cmdline;
> -	int ret = 0;
> -	int n = 0, entries = 0, modct = 0;
>  
>  	if (&__start___dyndbg == &__stop___dyndbg) {
>  		if (IS_ENABLED(CONFIG_DYNAMIC_DEBUG)) {
> @@ -1074,30 +1073,32 @@ static int __init dynamic_debug_init(void)
>  		ddebug_init_success = 1;
>  		return 0;
>  	}
> -	iter = __start___dyndbg;
> +
> +	iter = iter_mod_start = __start___dyndbg;
>  	modname = iter->modname;
> -	iter_start = iter;
> -	for (; iter < __stop___dyndbg; iter++) {
> -		entries++;
> +	i = mod_sites = mod_ct = 0;
> +
> +	for (; iter < __stop___dyndbg; iter++, i++, mod_sites++) {
> +

Just a small nit here - not sure why there's an extra blank line here?
But either way:

Acked-by: Jason Baron <jbaron@akamai.com>


>  		if (strcmp(modname, iter->modname)) {
> -			modct++;
> -			ret = ddebug_add_module(iter_start, n, modname);
> +			mod_ct++;
> +			ret = ddebug_add_module(iter_mod_start, mod_sites, modname);
>  			if (ret)
>  				goto out_err;
> -			n = 0;
> +
> +			mod_sites = 0;
>  			modname = iter->modname;
> -			iter_start = iter;
> +			iter_mod_start = iter;
>  		}
> -		n++;
>  	}
> -	ret = ddebug_add_module(iter_start, n, modname);
> +	ret = ddebug_add_module(iter_mod_start, mod_sites, modname);
>  	if (ret)
>  		goto out_err;
>  
>  	ddebug_init_success = 1;
>  	vpr_info("%d prdebugs in %d modules, %d KiB in ddebug tables, %d kiB in __dyndbg section\n",
> -		 entries, modct, (int)((modct * sizeof(struct ddebug_table)) >> 10),
> -		 (int)((entries * sizeof(struct _ddebug)) >> 10));
> +		 i, mod_ct, (int)((mod_ct * sizeof(struct ddebug_table)) >> 10),
> +		 (int)((i * sizeof(struct _ddebug)) >> 10));
>  
>  	/* now that ddebug tables are loaded, process all boot args
>  	 * again to find and activate queries given in dyndbg params.

Re: [PATCH v6 21/57] dyndbg: test DECLARE_DYNDBG_CLASSMAP, sysfs nodes

[Greg KH]

On Sun, Sep 04, 2022 at 03:40:58PM -0600, Jim Cromie wrote:
> Demonstrate use of DECLARE_DYNDBG_CLASSMAP macro, and expose them as
> sysfs-nodes for testing.

Wait, why sysfs?

sysfs isn't for testing, why not use debugfs?


> 
> For each of the 4 class-map-types:
> 
>   - declare a class-map of that type,
>   - declare the enum corresponding to those class-names
>   - share _base across 0..30 range
>   - add a __pr_debug_cls() call for each class-name
>   - declare 2 sysnodes for each class-map
>     for 'p' flag, and future 'T' flag
> 
> These declarations create the following sysfs parameter interface:
> 
>   :#> pwd
>   /sys/module/test_dynamic_debug/parameters
>   :#> ls
>   T_disjoint_bits  T_disjoint_names  T_level_names  T_level_num  do_prints
>   p_disjoint_bits  p_disjoint_names  p_level_names  p_level_num

What is in these files?

For sysfs stuff, you need Documentation/ABI entries so that you can't
abuse sysfs.  With debugfs, you can do anything you want :)

thanks,

greg k-h

Re: [PATCH v6 21/57] dyndbg: test DECLARE_DYNDBG_CLASSMAP, sysfs nodes

[Greg KH]

On Wed, Sep 07, 2022 at 04:54:00PM +0200, Greg KH wrote:
> On Sun, Sep 04, 2022 at 03:40:58PM -0600, Jim Cromie wrote:
> > Demonstrate use of DECLARE_DYNDBG_CLASSMAP macro, and expose them as
> > sysfs-nodes for testing.
> 
> Wait, why sysfs?
> 
> sysfs isn't for testing, why not use debugfs?
> 
> 
> > 
> > For each of the 4 class-map-types:
> > 
> >   - declare a class-map of that type,
> >   - declare the enum corresponding to those class-names
> >   - share _base across 0..30 range
> >   - add a __pr_debug_cls() call for each class-name
> >   - declare 2 sysnodes for each class-map
> >     for 'p' flag, and future 'T' flag
> > 
> > These declarations create the following sysfs parameter interface:
> > 
> >   :#> pwd
> >   /sys/module/test_dynamic_debug/parameters
> >   :#> ls
> >   T_disjoint_bits  T_disjoint_names  T_level_names  T_level_num  do_prints
> >   p_disjoint_bits  p_disjoint_names  p_level_names  p_level_num
> 
> What is in these files?
> 
> For sysfs stuff, you need Documentation/ABI entries so that you can't
> abuse sysfs.  With debugfs, you can do anything you want :)

Ah, it's just module parameter abuse, not a "normal" sysfs file at all :)

Nevermind, sorry for the noise...

greg k-h

Re: [PATCH v6 00/57] DYNDBG: opt-in class'd debug for modules, use in drm.

[Greg KH]

On Sun, Sep 04, 2022 at 03:40:37PM -0600, Jim Cromie wrote:
> hi Greg, Jason, DRM-folk, Steven,
> 
> If Im not too late for linux-next in this cycle, heres V6.  Diffs are minor:
> 
>  - rebased onto e47eb90a0a9a (tag: next-20220901, linux-next/master)
>    gets past Kconfig conflict, same for drm-tip.
>  - uint debug_level, not ulong.  to fit nouveau.
>  - -1 on param-read-back, to match prev write val.
>  - added back tracefs parts, missing from -V5
>    updated for tracing/events: Add __vstring() and __assign_vstr() helper macros
>    no decorations-lite in TP_printk, do it right later.
>  - commit-msg tweaks
> 
> Theres also new RFC stuff with the potential to reduce the size of the
> __dyndbgs section by 20%.  Not ready for prime time, or linux-next,
> but I hope compelling.
> 
> FEATURE DESCRIPTION
> 
> dyndbg provides DECLARE_DYNAMIC_DEBUG_CLASSMAP() which allows module
> authors to declare "good" class-names, of 4 types.
> 
>   DYNAMIC_DEBUG_CLASSMAP(drm_debug_classes,
>   			DD_CLASS_TYPE_DISJOINT_BITS, offset,
>                         "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");
> 
> That usage authorizes dyndbg to set class'd pr_debugs accordingly:
> 
>   echo class DRM_UT_CORE +p > /proc/dynamic_debug/control
>   echo class DRM_UT_KMS  +p > /proc/dynamic_debug/control
> 
> Because the DRM modules declare the same classes, they each authorize
> dyndbg with the same classnames, which allows dyndbg to effect changes
> to its selected class'd prdbgs.
> 
> Opting in by using the macro effectively privatizes the limited
> 63-classes available per module; only modules which share classnames
> must coordinate their use of the common range, and they can
> independently use the remaining id-space.
> 
> Other dyndbg filtering pertains too, so single sites can be selected.
> 
> 
> 4 DD_CLASS_TYPE_*_*s determine 2 behaviors:
> 
>   DISJOINT	bits are independent, like drm.debug categories
>   LEVELs	3>2, turns on level-2, like nouveau debug-levels
>   NUM/BITS	numeric input, bitmap if disjoint, else 0-32.
>   NAMES		accept proper names, like DRM_UT_CORE
> 
> Dyndbg provides param-callbacks which enforce those behaviors:
> 
>   # DISJOINT_BITS
>   echo 0x03 > /sys/module/drm/parameters/debug
> 
>   # LEVEL_NUM
>   echo 3 > /sys/module/drm/nouveau/debug-mumble*
> 
>   # DISJOINT_NAMES
>   echo +DRM_UT_CORE,+DRM_UT_KMS,-DRM_UT_DRIVER > /sys/module/drm/parameters/debug_categories
> 
>   # LEVEL_NAMES
>   echo NV_TRACE > /sys/module/nouveau/parameters/debug-mumble*
> 
> That design choice is allowed cuz verbosity is always attached to a
> (user visible) interface, and theres no reason not to put the
> implementation there (in the callback).  It also considerably
> simplifies things; ddebug_change can treat class_id's as disjoint,
> period.
> 

I've applied the first 21 patches in this series to my
driver-core-testing branch, and if 0-day doesn't blow up on it, I'll
move it to my -next branch tomorrow and it will get a wider testing
range in the linux-next releases.

Feel free to rebase the rest of the series on top of my tree and
resubmit after addressing Daniel's comments.

thanks,

greg k-h

Re: [PATCH v6 17/57] dyndbg: validate class FOO by checking with module

[Jason Baron]

On 9/4/22 17:40, Jim Cromie wrote:
> Add module-to-class validation:
> 
>   #> echo class DRM_UT_KMS +p > /proc/dynamic_debug/control
> 
> If a query has "class FOO", then ddebug_find_valid_class(), called
> from ddebug_change(), requires that FOO is known to module X,
> otherwize the query is skipped entirely for X.  This protects each
> module's class-space, other than the default:31.
> 
> The authors' choice of FOO is highly selective, giving isolation
> and/or coordinated sharing of FOOs.  For example, only DRM modules
> should know and respond to DRM_UT_KMS.
> 
> So this, combined with module's opt-in declaration of known classes,
> effectively privatizes the .class_id space for each module (or
> coordinated set of modules).
> 
> Notes:
> 
> For all "class FOO" queries, ddebug_find_valid_class() is called, it
> returns the map matching the query, and sets valid_class via an
> *outvar).
> 
> If no "class FOO" is supplied, valid_class = _CLASS_DFLT.  This
> insures that legacy queries do not trample on new class'd callsites,
> as they get added.


Hi Jim,

I'm wondering about the case where we have a callsite which is marked
as 'class foo', but the query string is done by say module and file, so:

# echo "module bar file foo.c +p" > /proc/dynamic_debug_control

With the proposed code, I think this ends up not enabling anything right?
Because valid class is set to _DPRINTK_CLASS_DFLT and then:
'dp->class_id != valid_class' is true?

This seems confusing to me as a user as this doesn't work like the
other queries....so maybe we should only do the
'dp->class_id != valid_class' check *if* query->class_string is set,
see below.



> 
> Also add a new column to control-file output, displaying non-default
> class-name (when found) or the "unknown _id:", if it has not been
> (correctly) declared with one of the declarator macros.
> 
> Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
> ---
>  lib/dynamic_debug.c | 76 ++++++++++++++++++++++++++++++++++++++++-----
>  1 file changed, 68 insertions(+), 8 deletions(-)
> 
> diff --git a/lib/dynamic_debug.c b/lib/dynamic_debug.c
> index b71efd0b491d..db96ded78c3f 100644
> --- a/lib/dynamic_debug.c
> +++ b/lib/dynamic_debug.c
> @@ -56,6 +56,7 @@ struct ddebug_query {
>  	const char *module;
>  	const char *function;
>  	const char *format;
> +	const char *class_string;
>  	unsigned int first_lineno, last_lineno;
>  };
>  
> @@ -136,15 +137,33 @@ static void vpr_info_dq(const struct ddebug_query *query, const char *msg)
>  			fmtlen--;
>  	}
>  
> -	v3pr_info("%s: func=\"%s\" file=\"%s\" module=\"%s\" format=\"%.*s\" lineno=%u-%u\n",
> -		 msg,
> -		 query->function ?: "",
> -		 query->filename ?: "",
> -		 query->module ?: "",
> -		 fmtlen, query->format ?: "",
> -		 query->first_lineno, query->last_lineno);
> +	v3pr_info("%s: func=\"%s\" file=\"%s\" module=\"%s\" format=\"%.*s\" lineno=%u-%u class=%s\n",
> +		  msg,
> +		  query->function ?: "",
> +		  query->filename ?: "",
> +		  query->module ?: "",
> +		  fmtlen, query->format ?: "",
> +		  query->first_lineno, query->last_lineno, query->class_string);
>  }
>  
> +static struct ddebug_class_map *ddebug_find_valid_class(struct ddebug_table const *dt,
> +							  const char *class_string, int *class_id)
> +{
> +	struct ddebug_class_map *map;
> +	int idx;
> +
> +	list_for_each_entry(map, &dt->maps, link) {
> +		idx = match_string(map->class_names, map->length, class_string);
> +		if (idx >= 0) {
> +			*class_id = idx + map->base;
> +			return map;
> +		}
> +	}
> +	*class_id = -ENOENT;
> +	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
> @@ -159,6 +178,8 @@ static int ddebug_change(const struct ddebug_query *query,
>  	unsigned int newflags;
>  	unsigned int nfound = 0;
>  	struct flagsbuf fbuf, nbuf;
> +	struct ddebug_class_map *map = NULL;
> +	int __outvar valid_class;
>  
>  	/* search for matching ddebugs */
>  	mutex_lock(&ddebug_lock);
> @@ -169,9 +190,22 @@ static int ddebug_change(const struct ddebug_query *query,
>  		    !match_wildcard(query->module, dt->mod_name))
>  			continue;
>  
> +		if (query->class_string) {
> +			map = ddebug_find_valid_class(dt, query->class_string, &valid_class);
> +			if (!map)
> +				continue;

So remove the else here.

> +		} else {
> +			/* constrain query, do not touch class'd callsites */
> +			valid_class = _DPRINTK_CLASS_DFLT;
> +		}
> +
>  		for (i = 0; i < dt->num_ddebugs; i++) {
>  			struct _ddebug *dp = &dt->ddebugs[i];
>  
> +			/* match site against query-class */
> +			if (dp->class_id != valid_class)

And then make this: if (query->class_string && (dp->class_id != valid_class))

thoughts?


> +				continue;
> +>  			/* match against the source filename */
>  			if (query->filename &&
>  			    !match_wildcard(query->filename, dp->filename) &&
> @@ -420,6 +454,8 @@ static int ddebug_parse_query(char *words[], int nwords,
>  		} else if (!strcmp(keyword, "line")) {
>  			if (parse_linerange(query, arg))
>  				return -EINVAL;
> +		} else if (!strcmp(keyword, "class")) {
> +			rc = check_set(&query->class_string, arg, "class");
>  		} else {
>  			pr_err("unknown keyword \"%s\"\n", keyword);
>  			return -EINVAL;
> @@ -854,6 +890,20 @@ static void *ddebug_proc_next(struct seq_file *m, void *p, loff_t *pos)
>  	return dp;
>  }
>  
> +#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)
> +{
> +	struct ddebug_class_map *map;
> +
> +	list_for_each_entry(map, &iter->table->maps, link)
> +		if (class_in_range(dp->class_id, map))
> +			return map->class_names[dp->class_id - map->base];
> +
> +	return NULL;
> +}
> +
>  /*
>   * Seq_ops show method.  Called several times within a read()
>   * call from userspace, with ddebug_lock held.  Formats the
> @@ -865,6 +915,7 @@ static int ddebug_proc_show(struct seq_file *m, void *p)
>  	struct ddebug_iter *iter = m->private;
>  	struct _ddebug *dp = p;
>  	struct flagsbuf flags;
> +	char const *class;
>  
>  	if (p == SEQ_START_TOKEN) {
>  		seq_puts(m,
> @@ -877,7 +928,16 @@ static int ddebug_proc_show(struct seq_file *m, void *p)
>  		   iter->table->mod_name, dp->function,
>  		   ddebug_describe_flags(dp->flags, &flags));
>  	seq_escape_str(m, dp->format, ESCAPE_SPACE, "\t\r\n\"");
> -	seq_puts(m, "\"\n");
> +	seq_puts(m, "\"");
> +
> +	if (dp->class_id != _DPRINTK_CLASS_DFLT) {
> +		class = ddebug_class_name(iter, dp);
> +		if (class)
> +			seq_printf(m, " class:%s", class);
> +		else
> +			seq_printf(m, " class unknown, _id:%d", dp->class_id);
> +	}
> +	seq_puts(m, "\n");
>  
>  	return 0;
>  }

Re: [PATCH v6 23/57] drm: POC drm on dyndbg - use in core, 2 helpers, 3 drivers.

[jim.cromie]

On Wed, Sep 7, 2022 at 12:13 AM Daniel Vetter <daniel@ffwll.ch> wrote:
>
> On Sun, Sep 04, 2022 at 03:41:00PM -0600, Jim Cromie wrote:
> > Use DECLARE_DYNDBG_CLASSMAP across DRM:
> >
> >  - in .c files, since macro defines/initializes a record
> >
> >  - in drivers, $mod_{drv,drm,param}.c
> >    ie where param setup is done, since a classmap is param related
> >
> >  - in drm/drm_print.c
> >    since existing __drm_debug param is defined there,
> >    and we ifdef it, and provide an elaborated alternative.
> >
> >  - in drm_*_helper modules:
> >    dp/drm_dp - 1st item in makefile target
> >    drivers/gpu/drm/drm_crtc_helper.c - random pick iirc.
> >
> > Since these modules all use identical CLASSMAP declarations (ie: names
> > and .class_id's) they will all respond together to "class DRM_UT_*"
> > query-commands:
> >
> >   :#> echo class DRM_UT_KMS +p > /proc/dynamic_debug/control
> >
> > NOTES:
> >
> > This changes __drm_debug from int to ulong, so BIT() is usable on it.
> >
> > DRM's enum drm_debug_category values need to sync with the index of
> > their respective class-names here.  Then .class_id == category, and
> > dyndbg's class FOO mechanisms will enable drm_dbg(DRM_UT_KMS, ...).
> >
> > Though DRM needs consistent categories across all modules, thats not
> > generally needed; modules X and Y could define FOO differently (ie a
> > different NAME => class_id mapping), changes are made according to
> > each module's private class-map.
> >
> > No callsites are actually selected by this patch, since none are
> > class'd yet.
> >
> > Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
>
> So maybe I should just try, but what happens if a drm module doesn't have
> these classbits declared? You simply have to use the raw number instead?

without the classnames declared via macro,
dyndbg has no names by which to validate the query.
raw class numbers are not usable into >control.
This is what privatizes the module's class-id space.

If the macro is missing, the drm_dbg()s ( after conversion to reside
atop dyndbg)
will do this in `cat control`
                        seq_printf(m, " class unknown, _id:%d", dp->class_id);



>
> > ---
> >  drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c | 14 +++++++++++++
> >  drivers/gpu/drm/display/drm_dp_helper.c | 13 ++++++++++++
> >  drivers/gpu/drm/drm_crtc_helper.c       | 13 ++++++++++++
> >  drivers/gpu/drm/drm_print.c             | 27 +++++++++++++++++++++++--
> >  drivers/gpu/drm/i915/i915_params.c      | 12 +++++++++++
> >  drivers/gpu/drm/nouveau/nouveau_drm.c   | 13 ++++++++++++
> >  include/drm/drm_print.h                 |  3 ++-
> >  7 files changed, 92 insertions(+), 3 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c
> > index de7144b06e93..97e184f44a52 100644
> > --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c
> > +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c
> > @@ -38,6 +38,8 @@
> >  #include <linux/mmu_notifier.h>
> >  #include <linux/suspend.h>
> >  #include <linux/cc_platform.h>
> > +#include <linux/fb.h>
> > +#include <linux/dynamic_debug.h>
> >
> >  #include "amdgpu.h"
> >  #include "amdgpu_irq.h"
> > @@ -185,6 +187,18 @@ int amdgpu_vcnfw_log;
> >
> >  static void amdgpu_drv_delayed_reset_work_handler(struct work_struct *work);
> >
> > +DECLARE_DYNDBG_CLASSMAP(drm_debug_classes, DD_CLASS_TYPE_DISJOINT_BITS, 0,
>
> Iirc we've talked about maybe some kbuild trickery so that any module
> under drivers/gpu/drm gets these by default. I don't think we need to have
> this for the first cut, but a macro to avoid the copypaste mistakes would
> be really good here.

It *may be* that theres a perfect place to declare it once, for everyone.
For me thats exploratory, error prone.
Proving that the sub-optimal worked seemed a good place to stop.

that said, theres a macro in test-dynamic-debug that is a candidate
for wider availability - it needs a better name

#define DD_SYS_WRAP(_model, _flags)                                     \
        static unsigned long bits_##_model;                             \
        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)

Re: [PATCH v6 17/57] dyndbg: validate class FOO by checking with module

[jim.cromie]

On Wed, Sep 7, 2022 at 12:19 PM Jason Baron <jbaron@akamai.com> wrote:
>
>
>
> On 9/4/22 17:40, Jim Cromie wrote:
> > Add module-to-class validation:
> >
> >   #> echo class DRM_UT_KMS +p > /proc/dynamic_debug/control
> >
> > If a query has "class FOO", then ddebug_find_valid_class(), called
> > from ddebug_change(), requires that FOO is known to module X,
> > otherwize the query is skipped entirely for X.  This protects each
> > module's class-space, other than the default:31.
> >
> > The authors' choice of FOO is highly selective, giving isolation
> > and/or coordinated sharing of FOOs.  For example, only DRM modules
> > should know and respond to DRM_UT_KMS.
> >
> > So this, combined with module's opt-in declaration of known classes,
> > effectively privatizes the .class_id space for each module (or
> > coordinated set of modules).
> >
> > Notes:
> >
> > For all "class FOO" queries, ddebug_find_valid_class() is called, it
> > returns the map matching the query, and sets valid_class via an
> > *outvar).
> >
> > If no "class FOO" is supplied, valid_class = _CLASS_DFLT.  This
> > insures that legacy queries do not trample on new class'd callsites,
> > as they get added.
>
>
> Hi Jim,
>
> I'm wondering about the case where we have a callsite which is marked
> as 'class foo', but the query string is done by say module and file, so:
>
> # echo "module bar file foo.c +p" > /proc/dynamic_debug_control
>
> With the proposed code, I think this ends up not enabling anything right?

correct - the only way to enable :    pr_debug_cls(CL_FOO, " ...")
is
   echo class CL_FOO +p > control

1st, existing dyndbg query uses, whether ad-hoc or scripted,
were not written in anticipation of new / classified subsystems.

2nd, new class users dont want to sit in coach. no damn legroom.

3rd, consider DRM, which already has drm.debug
ie:  /sys/module/drm/parameters/debug
and prefers it, at least by inertia.
protecting these new class'd callsites (3-5k of them)
from casual (unintended) manipulations of the kernel-wide
dyndbg state seems prudent, and a usability win.

Not everyone will use module bar, requiring "class foo"
guarantees that changes are intentional.



> Because valid class is set to _DPRINTK_CLASS_DFLT and then:
> 'dp->class_id != valid_class' is true?
>
> This seems confusing to me as a user as this doesn't work like the
> other queries....so maybe we should only do the
> 'dp->class_id != valid_class' check *if* query->class_string is set,
> see below.
>

Could you clarify whether you think this is a logic error
or a frame-of-reference difference as elaborated above ?

ISTM theres a place for a well-worded paragraph in doc
about the class distinction, perhaps a whole for-authors section.



>
>
> >
> > Also add a new column to control-file output, displaying non-default
> > class-name (when found) or the "unknown _id:", if it has not been
> > (correctly) declared with one of the declarator macros.
> >
> > Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
> > ---
> >  lib/dynamic_debug.c | 76 ++++++++++++++++++++++++++++++++++++++++-----
> >  1 file changed, 68 insertions(+), 8 deletions(-)
> >
> > diff --git a/lib/dynamic_debug.c b/lib/dynamic_debug.c
> > index b71efd0b491d..db96ded78c3f 100644
> > --- a/lib/dynamic_debug.c
> > +++ b/lib/dynamic_debug.c
> > @@ -56,6 +56,7 @@ struct ddebug_query {
> >       const char *module;
> >       const char *function;
> >       const char *format;
> > +     const char *class_string;
> >       unsigned int first_lineno, last_lineno;
> >  };
> >
> > @@ -136,15 +137,33 @@ static void vpr_info_dq(const struct ddebug_query *query, const char *msg)
> >                       fmtlen--;
> >       }
> >
> > -     v3pr_info("%s: func=\"%s\" file=\"%s\" module=\"%s\" format=\"%.*s\" lineno=%u-%u\n",
> > -              msg,
> > -              query->function ?: "",
> > -              query->filename ?: "",
> > -              query->module ?: "",
> > -              fmtlen, query->format ?: "",
> > -              query->first_lineno, query->last_lineno);
> > +     v3pr_info("%s: func=\"%s\" file=\"%s\" module=\"%s\" format=\"%.*s\" lineno=%u-%u class=%s\n",
> > +               msg,
> > +               query->function ?: "",
> > +               query->filename ?: "",
> > +               query->module ?: "",
> > +               fmtlen, query->format ?: "",
> > +               query->first_lineno, query->last_lineno, query->class_string);
> >  }
> >
> > +static struct ddebug_class_map *ddebug_find_valid_class(struct ddebug_table const *dt,
> > +                                                       const char *class_string, int *class_id)
> > +{
> > +     struct ddebug_class_map *map;
> > +     int idx;
> > +
> > +     list_for_each_entry(map, &dt->maps, link) {
> > +             idx = match_string(map->class_names, map->length, class_string);
> > +             if (idx >= 0) {
> > +                     *class_id = idx + map->base;
> > +                     return map;
> > +             }
> > +     }
> > +     *class_id = -ENOENT;
> > +     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
> > @@ -159,6 +178,8 @@ static int ddebug_change(const struct ddebug_query *query,
> >       unsigned int newflags;
> >       unsigned int nfound = 0;
> >       struct flagsbuf fbuf, nbuf;
> > +     struct ddebug_class_map *map = NULL;
> > +     int __outvar valid_class;
> >
> >       /* search for matching ddebugs */
> >       mutex_lock(&ddebug_lock);
> > @@ -169,9 +190,22 @@ static int ddebug_change(const struct ddebug_query *query,
> >                   !match_wildcard(query->module, dt->mod_name))
> >                       continue;
> >
> > +             if (query->class_string) {
> > +                     map = ddebug_find_valid_class(dt, query->class_string, &valid_class);
> > +                     if (!map)
> > +                             continue;
>
> So remove the else here.
>
> > +             } else {
> > +                     /* constrain query, do not touch class'd callsites */
> > +                     valid_class = _DPRINTK_CLASS_DFLT;
> > +             }
> > +
> >               for (i = 0; i < dt->num_ddebugs; i++) {
> >                       struct _ddebug *dp = &dt->ddebugs[i];
> >
> > +                     /* match site against query-class */
> > +                     if (dp->class_id != valid_class)
>
> And then make this: if (query->class_string && (dp->class_id != valid_class))
>
> thoughts?
>
>
> > +                             continue;
> > +>                    /* match against the source filename */
> >                       if (query->filename &&
> >                           !match_wildcard(query->filename, dp->filename) &&
> > @@ -420,6 +454,8 @@ static int ddebug_parse_query(char *words[], int nwords,
> >               } else if (!strcmp(keyword, "line")) {
> >                       if (parse_linerange(query, arg))
> >                               return -EINVAL;
> > +             } else if (!strcmp(keyword, "class")) {
> > +                     rc = check_set(&query->class_string, arg, "class");
> >               } else {
> >                       pr_err("unknown keyword \"%s\"\n", keyword);
> >                       return -EINVAL;
> > @@ -854,6 +890,20 @@ static void *ddebug_proc_next(struct seq_file *m, void *p, loff_t *pos)
> >       return dp;
> >  }
> >
> > +#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)
> > +{
> > +     struct ddebug_class_map *map;
> > +
> > +     list_for_each_entry(map, &iter->table->maps, link)
> > +             if (class_in_range(dp->class_id, map))
> > +                     return map->class_names[dp->class_id - map->base];
> > +
> > +     return NULL;
> > +}
> > +
> >  /*
> >   * Seq_ops show method.  Called several times within a read()
> >   * call from userspace, with ddebug_lock held.  Formats the
> > @@ -865,6 +915,7 @@ static int ddebug_proc_show(struct seq_file *m, void *p)
> >       struct ddebug_iter *iter = m->private;
> >       struct _ddebug *dp = p;
> >       struct flagsbuf flags;
> > +     char const *class;
> >
> >       if (p == SEQ_START_TOKEN) {
> >               seq_puts(m,
> > @@ -877,7 +928,16 @@ static int ddebug_proc_show(struct seq_file *m, void *p)
> >                  iter->table->mod_name, dp->function,
> >                  ddebug_describe_flags(dp->flags, &flags));
> >       seq_escape_str(m, dp->format, ESCAPE_SPACE, "\t\r\n\"");
> > -     seq_puts(m, "\"\n");
> > +     seq_puts(m, "\"");
> > +
> > +     if (dp->class_id != _DPRINTK_CLASS_DFLT) {
> > +             class = ddebug_class_name(iter, dp);
> > +             if (class)
> > +                     seq_printf(m, " class:%s", class);
> > +             else
> > +                     seq_printf(m, " class unknown, _id:%d", dp->class_id);
> > +     }
> > +     seq_puts(m, "\n");
> >
> >       return 0;
> >  }

Re: [PATCH v6 28/57] drm_print: refine drm_debug_enabled for jump-label

[jim.cromie]

On Wed, Sep 7, 2022 at 12:40 AM Daniel Vetter <daniel@ffwll.ch> wrote:
>
> On Sun, Sep 04, 2022 at 03:41:05PM -0600, Jim Cromie wrote:
> > In order to use dynamic-debug's jump-label optimization in drm-debug,
> > its clarifying to refine drm_debug_enabled into 3 uses:
> >
> > 1.   drm_debug_enabled - legacy, public
> > 2. __drm_debug_enabled - optimized for dyndbg jump-label enablement.
> > 3.  _drm_debug_enabled - pr_debug instrumented, observable
> >
> > 1. The legacy version always checks the bits.
> >
> > 2. is privileged, for use by __drm_dbg(), __drm_dev_dbg(), which do an
> > early return unless the category is enabled.  For dyndbg builds, debug
> > callsites are selectively "pre-enabled", so __drm_debug_enabled()
> > short-circuits to true there.  Remaining callers of 1 may be able to
> > use 2, case by case.
> >
> > 3. is 1st wrapped in a macro, with a pr_debug, which reports each
> > usage in /proc/dynamic_debug/control, making it observable in the
> > logs.  The macro lets the pr_debug see the real caller, not an inline
> > function.
> >
> > When plugged into 1, 3 identified ~10 remaining callers of the
> > function, leading to the follow-on cleanup patch, and would allow
> > activating the pr_debugs, estimating the callrate, and the potential
> > savings by using the wrapper macro.  It is unused ATM, but it fills
> > out the picture.
> >
> > Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
>
> So instead of having 3 here as a "you need to hack it in to see what
> should be converted" I have a bit a different idea: Could we make the
> public version also a dyndbg callsite (like the printing wrappers), but
> instead of a dynamic call we'd have a dynamically fixed value we get out?
> I think that would take care of everything you have here as an open.
>
> Otherwise I'd just drop 3 for the series we're going to merge.
> -Daniel
>

OK - So here it is in use again,  with  modules drm amdgpu i915 loaded + deps

:#> grep todo /proc/dynamic_debug/control
drivers/gpu/drm/drm_edid_load.c:178 [drm]edid_load =_ "todo: maybe
avoid via dyndbg\n"
drivers/gpu/drm/drm_vblank.c:410 [drm]drm_crtc_accurate_vblank_count
=_ "todo: maybe avoid via dyndbg\n"
drivers/gpu/drm/drm_vblank.c:787
[drm]drm_crtc_vblank_helper_get_vblank_timestamp_internal =_ "todo:
maybe avoid via dyndbg\n"
drivers/gpu/drm/drm_vblank.c:1491 [drm]drm_vblank_restore =_ "todo:
maybe avoid via dyndbg\n"
drivers/gpu/drm/drm_vblank.c:1433 [drm]drm_vblank_enable =_ "todo:
maybe avoid via dyndbg\n"
drivers/gpu/drm/drm_plane.c:2168 [drm]drm_mode_setplane =_ "todo:
maybe avoid via dyndbg\n"
drivers/gpu/drm/display/drm_dp_mst_topology.c:1359
[drm_display_helper]drm_dp_mst_wait_tx_reply =_ "todo: maybe avoid via
dyndbg\n"
drivers/gpu/drm/display/drm_dp_mst_topology.c:2864
[drm_display_helper]process_single_tx_qlock =_ "todo: maybe avoid via
dyndbg\n"
drivers/gpu/drm/display/drm_dp_mst_topology.c:2909
[drm_display_helper]drm_dp_queue_down_tx =_ "todo: maybe avoid via
dyndbg\n"
drivers/gpu/drm/display/drm_dp_mst_topology.c:1686
[drm_display_helper]drm_dp_mst_update_slots =_ "todo: maybe avoid via
dyndbg\n"
drivers/gpu/drm/i915/display/intel_dp.c:1111
[i915]intel_dp_print_rates =_ "todo: maybe avoid via dyndbg\n"
drivers/gpu/drm/i915/display/intel_backlight.c:5434
[i915]cnp_enable_backlight =_ "todo: maybe avoid via dyndbg\n"
drivers/gpu/drm/i915/display/intel_backlight.c:5459
[i915]intel_backlight_device_register =_ "todo: maybe avoid via
dyndbg\n"
drivers/gpu/drm/i915/display/intel_opregion.c:43
[i915]intel_opregion_notify_encoder =_ "todo: maybe avoid via
dyndbg\n"
drivers/gpu/drm/i915/display/intel_opregion.c:53
[i915]asle_set_backlight =_ "todo: maybe avoid via dyndbg\n"
drivers/gpu/drm/i915/display/intel_bios.c:1088
[i915]intel_bios_is_dsi_present =_ "todo: maybe avoid via dyndbg\n"
drivers/gpu/drm/i915/display/intel_display_debugfs.c:6153
[i915]i915_drrs_ctl_set =_ "todo: maybe avoid via dyndbg\n"
drivers/gpu/drm/i915/intel_pcode.c:26 [i915]snb_pcode_read =_ "todo:
maybe avoid via dyndbg\n"
drivers/gpu/drm/i915/i915_getparam.c:785 [i915]i915_getparam_ioctl =_
"todo: maybe avoid via dyndbg\n"
drivers/gpu/drm/amd/amdgpu/vcn_v2_5.c:282
[amdgpu]vcn_v2_5_process_interrupt =_ "todo: maybe avoid via dyndbg\n"
drivers/gpu/drm/amd/amdgpu/vcn_v2_0.c:433
[amdgpu]vcn_v2_0_process_interrupt =_ "todo: maybe avoid via dyndbg\n"

w/o actually looking, the vblank debug could be called frequently.
I'll build on my amdgpu box to run on real hardware.

And Im inclined to restore the instrumented version (with the "todo:")
care to suggest a better message than "maybe avoid" ?

Re: [PATCH v6 17/57] dyndbg: validate class FOO by checking with module

[Jason Baron]

On 9/9/22 16:44, jim.cromie@gmail.com wrote:
> On Wed, Sep 7, 2022 at 12:19 PM Jason Baron <jbaron@akamai.com> wrote:
>>
>>
>>
>> On 9/4/22 17:40, Jim Cromie wrote:
>>> Add module-to-class validation:
>>>
>>>   #> echo class DRM_UT_KMS +p > /proc/dynamic_debug/control
>>>
>>> If a query has "class FOO", then ddebug_find_valid_class(), called
>>> from ddebug_change(), requires that FOO is known to module X,
>>> otherwize the query is skipped entirely for X.  This protects each
>>> module's class-space, other than the default:31.
>>>
>>> The authors' choice of FOO is highly selective, giving isolation
>>> and/or coordinated sharing of FOOs.  For example, only DRM modules
>>> should know and respond to DRM_UT_KMS.
>>>
>>> So this, combined with module's opt-in declaration of known classes,
>>> effectively privatizes the .class_id space for each module (or
>>> coordinated set of modules).
>>>
>>> Notes:
>>>
>>> For all "class FOO" queries, ddebug_find_valid_class() is called, it
>>> returns the map matching the query, and sets valid_class via an
>>> *outvar).
>>>
>>> If no "class FOO" is supplied, valid_class = _CLASS_DFLT.  This
>>> insures that legacy queries do not trample on new class'd callsites,
>>> as they get added.
>>
>>
>> Hi Jim,
>>
>> I'm wondering about the case where we have a callsite which is marked
>> as 'class foo', but the query string is done by say module and file, so:
>>
>> # echo "module bar file foo.c +p" > /proc/dynamic_debug_control
>>
>> With the proposed code, I think this ends up not enabling anything right?
> 
> correct - the only way to enable :    pr_debug_cls(CL_FOO, " ...")
> is
>    echo class CL_FOO +p > control
> 
> 1st, existing dyndbg query uses, whether ad-hoc or scripted,
> were not written in anticipation of new / classified subsystems.
> 
> 2nd, new class users dont want to sit in coach. no damn legroom.
> 
> 3rd, consider DRM, which already has drm.debug
> ie:  /sys/module/drm/parameters/debug
> and prefers it, at least by inertia.
> protecting these new class'd callsites (3-5k of them)
> from casual (unintended) manipulations of the kernel-wide
> dyndbg state seems prudent, and a usability win.
> 
> Not everyone will use module bar, requiring "class foo"
> guarantees that changes are intentional.
> 

I sort of get that your trying to protect these from unintended toggling,
but I would say it's that's not really new with these statements,
prr_debug() come and go before and I'm not aware of this is an issue.
And in any case, a query can be modified.

I think what bugs me is now query stuff works differently. Previously,
all the query strings - 'module', 'file', 'line', 'format', were
used as additional selectors, but now we have this new one 'class'
that works differently as it's requited for pr_debug_cls() statements.

> 
> 
>> Because valid class is set to _DPRINTK_CLASS_DFLT and then:
>> 'dp->class_id != valid_class' is true?
>>
>> This seems confusing to me as a user as this doesn't work like the
>> other queries....so maybe we should only do the
>> 'dp->class_id != valid_class' check *if* query->class_string is set,
>> see below.
>>
> 
> Could you clarify whether you think this is a logic error
> or a frame-of-reference difference as elaborated above ?

'frame-of-reference' I'm questioning the how 'class' works as mentioned
above not the implementation.

Thanks,

-Jason

> 
> ISTM theres a place for a well-worded paragraph in doc
> about the class distinction, perhaps a whole for-authors section.
> 
> 
> 
>>
>>
>>>
>>> Also add a new column to control-file output, displaying non-default
>>> class-name (when found) or the "unknown _id:", if it has not been
>>> (correctly) declared with one of the declarator macros.
>>>
>>> Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
>>> ---
>>>  lib/dynamic_debug.c | 76 ++++++++++++++++++++++++++++++++++++++++-----
>>>  1 file changed, 68 insertions(+), 8 deletions(-)
>>>
>>> diff --git a/lib/dynamic_debug.c b/lib/dynamic_debug.c
>>> index b71efd0b491d..db96ded78c3f 100644
>>> --- a/lib/dynamic_debug.c
>>> +++ b/lib/dynamic_debug.c
>>> @@ -56,6 +56,7 @@ struct ddebug_query {
>>>       const char *module;
>>>       const char *function;
>>>       const char *format;
>>> +     const char *class_string;
>>>       unsigned int first_lineno, last_lineno;
>>>  };
>>>
>>> @@ -136,15 +137,33 @@ static void vpr_info_dq(const struct ddebug_query *query, const char *msg)
>>>                       fmtlen--;
>>>       }
>>>
>>> -     v3pr_info("%s: func=\"%s\" file=\"%s\" module=\"%s\" format=\"%.*s\" lineno=%u-%u\n",
>>> -              msg,
>>> -              query->function ?: "",
>>> -              query->filename ?: "",
>>> -              query->module ?: "",
>>> -              fmtlen, query->format ?: "",
>>> -              query->first_lineno, query->last_lineno);
>>> +     v3pr_info("%s: func=\"%s\" file=\"%s\" module=\"%s\" format=\"%.*s\" lineno=%u-%u class=%s\n",
>>> +               msg,
>>> +               query->function ?: "",
>>> +               query->filename ?: "",
>>> +               query->module ?: "",
>>> +               fmtlen, query->format ?: "",
>>> +               query->first_lineno, query->last_lineno, query->class_string);
>>>  }
>>>
>>> +static struct ddebug_class_map *ddebug_find_valid_class(struct ddebug_table const *dt,
>>> +                                                       const char *class_string, int *class_id)
>>> +{
>>> +     struct ddebug_class_map *map;
>>> +     int idx;
>>> +
>>> +     list_for_each_entry(map, &dt->maps, link) {
>>> +             idx = match_string(map->class_names, map->length, class_string);
>>> +             if (idx >= 0) {
>>> +                     *class_id = idx + map->base;
>>> +                     return map;
>>> +             }
>>> +     }
>>> +     *class_id = -ENOENT;
>>> +     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
>>> @@ -159,6 +178,8 @@ static int ddebug_change(const struct ddebug_query *query,
>>>       unsigned int newflags;
>>>       unsigned int nfound = 0;
>>>       struct flagsbuf fbuf, nbuf;
>>> +     struct ddebug_class_map *map = NULL;
>>> +     int __outvar valid_class;
>>>
>>>       /* search for matching ddebugs */
>>>       mutex_lock(&ddebug_lock);
>>> @@ -169,9 +190,22 @@ static int ddebug_change(const struct ddebug_query *query,
>>>                   !match_wildcard(query->module, dt->mod_name))
>>>                       continue;
>>>
>>> +             if (query->class_string) {
>>> +                     map = ddebug_find_valid_class(dt, query->class_string, &valid_class);
>>> +                     if (!map)
>>> +                             continue;
>>
>> So remove the else here.
>>
>>> +             } else {
>>> +                     /* constrain query, do not touch class'd callsites */
>>> +                     valid_class = _DPRINTK_CLASS_DFLT;
>>> +             }
>>> +
>>>               for (i = 0; i < dt->num_ddebugs; i++) {
>>>                       struct _ddebug *dp = &dt->ddebugs[i];
>>>
>>> +                     /* match site against query-class */
>>> +                     if (dp->class_id != valid_class)
>>
>> And then make this: if (query->class_string && (dp->class_id != valid_class))
>>
>> thoughts?
>>
>>
>>> +                             continue;
>>> +>                    /* match against the source filename */
>>>                       if (query->filename &&
>>>                           !match_wildcard(query->filename, dp->filename) &&
>>> @@ -420,6 +454,8 @@ static int ddebug_parse_query(char *words[], int nwords,
>>>               } else if (!strcmp(keyword, "line")) {
>>>                       if (parse_linerange(query, arg))
>>>                               return -EINVAL;
>>> +             } else if (!strcmp(keyword, "class")) {
>>> +                     rc = check_set(&query->class_string, arg, "class");
>>>               } else {
>>>                       pr_err("unknown keyword \"%s\"\n", keyword);
>>>                       return -EINVAL;
>>> @@ -854,6 +890,20 @@ static void *ddebug_proc_next(struct seq_file *m, void *p, loff_t *pos)
>>>       return dp;
>>>  }
>>>
>>> +#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)
>>> +{
>>> +     struct ddebug_class_map *map;
>>> +
>>> +     list_for_each_entry(map, &iter->table->maps, link)
>>> +             if (class_in_range(dp->class_id, map))
>>> +                     return map->class_names[dp->class_id - map->base];
>>> +
>>> +     return NULL;
>>> +}
>>> +
>>>  /*
>>>   * Seq_ops show method.  Called several times within a read()
>>>   * call from userspace, with ddebug_lock held.  Formats the
>>> @@ -865,6 +915,7 @@ static int ddebug_proc_show(struct seq_file *m, void *p)
>>>       struct ddebug_iter *iter = m->private;
>>>       struct _ddebug *dp = p;
>>>       struct flagsbuf flags;
>>> +     char const *class;
>>>
>>>       if (p == SEQ_START_TOKEN) {
>>>               seq_puts(m,
>>> @@ -877,7 +928,16 @@ static int ddebug_proc_show(struct seq_file *m, void *p)
>>>                  iter->table->mod_name, dp->function,
>>>                  ddebug_describe_flags(dp->flags, &flags));
>>>       seq_escape_str(m, dp->format, ESCAPE_SPACE, "\t\r\n\"");
>>> -     seq_puts(m, "\"\n");
>>> +     seq_puts(m, "\"");
>>> +
>>> +     if (dp->class_id != _DPRINTK_CLASS_DFLT) {
>>> +             class = ddebug_class_name(iter, dp);
>>> +             if (class)
>>> +                     seq_printf(m, " class:%s", class);
>>> +             else
>>> +                     seq_printf(m, " class unknown, _id:%d", dp->class_id);
>>> +     }
>>> +     seq_puts(m, "\n");
>>>
>>>       return 0;
>>>  }

Re: [PATCH v6 17/57] dyndbg: validate class FOO by checking with module

[jim.cromie]

On Mon, Sep 12, 2022 at 2:17 PM Jason Baron <jbaron@akamai.com> wrote:
>
>
>
> On 9/9/22 16:44, jim.cromie@gmail.com wrote:
> > On Wed, Sep 7, 2022 at 12:19 PM Jason Baron <jbaron@akamai.com> wrote:
> >>
> >>
> >>
> >> On 9/4/22 17:40, Jim Cromie wrote:
> >>> Add module-to-class validation:
> >>>
> >>>   #> echo class DRM_UT_KMS +p > /proc/dynamic_debug/control
> >>>
> >>> If a query has "class FOO", then ddebug_find_valid_class(), called
> >>> from ddebug_change(), requires that FOO is known to module X,
> >>> otherwize the query is skipped entirely for X.  This protects each
> >>> module's class-space, other than the default:31.
> >>>
> >>> The authors' choice of FOO is highly selective, giving isolation
> >>> and/or coordinated sharing of FOOs.  For example, only DRM modules
> >>> should know and respond to DRM_UT_KMS.
> >>>
> >>> So this, combined with module's opt-in declaration of known classes,
> >>> effectively privatizes the .class_id space for each module (or
> >>> coordinated set of modules).
> >>>
> >>> Notes:
> >>>
> >>> For all "class FOO" queries, ddebug_find_valid_class() is called, it
> >>> returns the map matching the query, and sets valid_class via an
> >>> *outvar).
> >>>
> >>> If no "class FOO" is supplied, valid_class = _CLASS_DFLT.  This
> >>> insures that legacy queries do not trample on new class'd callsites,
> >>> as they get added.
> >>
> >>
> >> Hi Jim,
> >>
> >> I'm wondering about the case where we have a callsite which is marked
> >> as 'class foo', but the query string is done by say module and file, so:
> >>
> >> # echo "module bar file foo.c +p" > /proc/dynamic_debug_control
> >>
> >> With the proposed code, I think this ends up not enabling anything right?
> >
> > correct - the only way to enable :    pr_debug_cls(CL_FOO, " ...")
> > is
> >    echo class CL_FOO +p > control
> >
> > 1st, existing dyndbg query uses, whether ad-hoc or scripted,
> > were not written in anticipation of new / classified subsystems.
> >
> > 2nd, new class users dont want to sit in coach. no damn legroom.
> >
> > 3rd, consider DRM, which already has drm.debug
> > ie:  /sys/module/drm/parameters/debug
> > and prefers it, at least by inertia.
> > protecting these new class'd callsites (3-5k of them)
> > from casual (unintended) manipulations of the kernel-wide
> > dyndbg state seems prudent, and a usability win.
> >
> > Not everyone will use module bar, requiring "class foo"
> > guarantees that changes are intentional.
> >
>
> I sort of get that your trying to protect these from unintended toggling,
> but I would say it's that's not really new with these statements,

Whats new here is the customer - a whole new subsystem.
theyre accustomed to a single point of control,
/sys/module/drm/parameters/debug,
and dont particularly value the infinite variety of combos under the hood.
Theyre here for (Im selling them on) the JUMP_LABEL.

Isolation from unintended manipulations under the hood
(which is afterall a global kernel state) seems like a good guarantee.

IOW class isolation from non-class, and from other INDEPENDENT classes.
Only LEVEL types have any interdependence, and only with the other level
classnames in the declared group.

Ultimately, whats the client want ?
I know my banker handles other folks money too,
but I can reasonably expect isolation from their businesses.

> prr_debug() come and go before and I'm not aware of this is an issue.
> And in any case, a query can be modified.

but youre requiring they be modified, so as not to scribble all over DRM_*,
which wasnt there when they fiddled.

> I think what bugs me is now query stuff works differently. Previously,
> all the query strings - 'module', 'file', 'line', 'format', were
> used as additional selectors, but now we have this new one 'class'
> that works differently as it's requited for pr_debug_cls() statements.
>

theres a "when-in-rome" argument here, if DRM is Rome.

> >
> >
> >> Because valid class is set to _DPRINTK_CLASS_DFLT and then:
> >> 'dp->class_id != valid_class' is true?
> >>
> >> This seems confusing to me as a user as this doesn't work like the
> >> other queries....so maybe we should only do the
> >> 'dp->class_id != valid_class' check *if* query->class_string is set,
> >> see below.
> >>
> >
> > Could you clarify whether you think this is a logic error
> > or a frame-of-reference difference as elaborated above ?
>
> 'frame-of-reference' I'm questioning the how 'class' works as mentioned
> above not the implementation.
>
> Thanks,
>
> -Jason
>
> >
> > ISTM theres a place for a well-worded paragraph in doc
> > about the class distinction, perhaps a whole for-authors section.
> >
> >
> >
> >>
> >>
> >>>
> >>> Also add a new column to control-file output, displaying non-default
> >>> class-name (when found) or the "unknown _id:", if it has not been
> >>> (correctly) declared with one of the declarator macros.
> >>>
> >>> Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
> >>> ---
> >>>  lib/dynamic_debug.c | 76 ++++++++++++++++++++++++++++++++++++++++-----
> >>>  1 file changed, 68 insertions(+), 8 deletions(-)
> >>>
> >>> diff --git a/lib/dynamic_debug.c b/lib/dynamic_debug.c
> >>> index b71efd0b491d..db96ded78c3f 100644
> >>> --- a/lib/dynamic_debug.c
> >>> +++ b/lib/dynamic_debug.c
> >>> @@ -56,6 +56,7 @@ struct ddebug_query {
> >>>       const char *module;
> >>>       const char *function;
> >>>       const char *format;
> >>> +     const char *class_string;
> >>>       unsigned int first_lineno, last_lineno;
> >>>  };
> >>>
> >>> @@ -136,15 +137,33 @@ static void vpr_info_dq(const struct ddebug_query *query, const char *msg)
> >>>                       fmtlen--;
> >>>       }
> >>>
> >>> -     v3pr_info("%s: func=\"%s\" file=\"%s\" module=\"%s\" format=\"%.*s\" lineno=%u-%u\n",
> >>> -              msg,
> >>> -              query->function ?: "",
> >>> -              query->filename ?: "",
> >>> -              query->module ?: "",
> >>> -              fmtlen, query->format ?: "",
> >>> -              query->first_lineno, query->last_lineno);
> >>> +     v3pr_info("%s: func=\"%s\" file=\"%s\" module=\"%s\" format=\"%.*s\" lineno=%u-%u class=%s\n",
> >>> +               msg,
> >>> +               query->function ?: "",
> >>> +               query->filename ?: "",
> >>> +               query->module ?: "",
> >>> +               fmtlen, query->format ?: "",
> >>> +               query->first_lineno, query->last_lineno, query->class_string);
> >>>  }
> >>>
> >>> +static struct ddebug_class_map *ddebug_find_valid_class(struct ddebug_table const *dt,
> >>> +                                                       const char *class_string, int *class_id)
> >>> +{
> >>> +     struct ddebug_class_map *map;
> >>> +     int idx;
> >>> +
> >>> +     list_for_each_entry(map, &dt->maps, link) {
> >>> +             idx = match_string(map->class_names, map->length, class_string);
> >>> +             if (idx >= 0) {
> >>> +                     *class_id = idx + map->base;
> >>> +                     return map;
> >>> +             }
> >>> +     }
> >>> +     *class_id = -ENOENT;
> >>> +     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
> >>> @@ -159,6 +178,8 @@ static int ddebug_change(const struct ddebug_query *query,
> >>>       unsigned int newflags;
> >>>       unsigned int nfound = 0;
> >>>       struct flagsbuf fbuf, nbuf;
> >>> +     struct ddebug_class_map *map = NULL;
> >>> +     int __outvar valid_class;
> >>>
> >>>       /* search for matching ddebugs */
> >>>       mutex_lock(&ddebug_lock);
> >>> @@ -169,9 +190,22 @@ static int ddebug_change(const struct ddebug_query *query,
> >>>                   !match_wildcard(query->module, dt->mod_name))
> >>>                       continue;
> >>>
> >>> +             if (query->class_string) {
> >>> +                     map = ddebug_find_valid_class(dt, query->class_string, &valid_class);
> >>> +                     if (!map)
> >>> +                             continue;
> >>
> >> So remove the else here.
> >>
> >>> +             } else {
> >>> +                     /* constrain query, do not touch class'd callsites */
> >>> +                     valid_class = _DPRINTK_CLASS_DFLT;
> >>> +             }
> >>> +
> >>>               for (i = 0; i < dt->num_ddebugs; i++) {
> >>>                       struct _ddebug *dp = &dt->ddebugs[i];
> >>>
> >>> +                     /* match site against query-class */
> >>> +                     if (dp->class_id != valid_class)
> >>
> >> And then make this: if (query->class_string && (dp->class_id != valid_class))
> >>
> >> thoughts?
> >>
> >>
> >>> +                             continue;
> >>> +>                    /* match against the source filename */
> >>>                       if (query->filename &&
> >>>                           !match_wildcard(query->filename, dp->filename) &&
> >>> @@ -420,6 +454,8 @@ static int ddebug_parse_query(char *words[], int nwords,
> >>>               } else if (!strcmp(keyword, "line")) {
> >>>                       if (parse_linerange(query, arg))
> >>>                               return -EINVAL;
> >>> +             } else if (!strcmp(keyword, "class")) {
> >>> +                     rc = check_set(&query->class_string, arg, "class");
> >>>               } else {
> >>>                       pr_err("unknown keyword \"%s\"\n", keyword);
> >>>                       return -EINVAL;
> >>> @@ -854,6 +890,20 @@ static void *ddebug_proc_next(struct seq_file *m, void *p, loff_t *pos)
> >>>       return dp;
> >>>  }
> >>>
> >>> +#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)
> >>> +{
> >>> +     struct ddebug_class_map *map;
> >>> +
> >>> +     list_for_each_entry(map, &iter->table->maps, link)
> >>> +             if (class_in_range(dp->class_id, map))
> >>> +                     return map->class_names[dp->class_id - map->base];
> >>> +
> >>> +     return NULL;
> >>> +}
> >>> +
> >>>  /*
> >>>   * Seq_ops show method.  Called several times within a read()
> >>>   * call from userspace, with ddebug_lock held.  Formats the
> >>> @@ -865,6 +915,7 @@ static int ddebug_proc_show(struct seq_file *m, void *p)
> >>>       struct ddebug_iter *iter = m->private;
> >>>       struct _ddebug *dp = p;
> >>>       struct flagsbuf flags;
> >>> +     char const *class;
> >>>
> >>>       if (p == SEQ_START_TOKEN) {
> >>>               seq_puts(m,
> >>> @@ -877,7 +928,16 @@ static int ddebug_proc_show(struct seq_file *m, void *p)
> >>>                  iter->table->mod_name, dp->function,
> >>>                  ddebug_describe_flags(dp->flags, &flags));
> >>>       seq_escape_str(m, dp->format, ESCAPE_SPACE, "\t\r\n\"");
> >>> -     seq_puts(m, "\"\n");
> >>> +     seq_puts(m, "\"");
> >>> +
> >>> +     if (dp->class_id != _DPRINTK_CLASS_DFLT) {
> >>> +             class = ddebug_class_name(iter, dp);
> >>> +             if (class)
> >>> +                     seq_printf(m, " class:%s", class);
> >>> +             else
> >>> +                     seq_printf(m, " class unknown, _id:%d", dp->class_id);
> >>> +     }
> >>> +     seq_puts(m, "\n");
> >>>
> >>>       return 0;
> >>>  }

Re: [PATCH v6 32/57] nouveau: adapt NV_DEBUG, NV_ATOMIC to use DRM.debug

[Timur Tabi]

On Sun, Sep 4, 2022 at 4:48 PM Jim Cromie <jim.cromie@gmail.com> wrote:
>
> These 2 macros used drm_debug_enabled() on DRM_UT_{DRIVER,ATOMIC}
> respectively, replace those with drm_dbg_##cat invocations.
>
> this results in new class'd prdbg callsites:
>
> :#> grep nouveau /proc/dynamic_debug/control | grep class | wc
>     116    1130   15584
> :#> grep nouveau /proc/dynamic_debug/control | grep class | grep DRIVER | wc
>      74     704    9709
> :#> grep nouveau /proc/dynamic_debug/control | grep class | grep ATOMIC | wc
>      31     307    4237
> :#> grep nouveau /proc/dynamic_debug/control | grep class | grep KMS | wc
>      11     119    1638
>
> the KMS entries are due to existing uses of drm_dbg_kms().
>
> Signed-off-by: Jim Cromie <jim.cromie@gmail.com>

Has this patch set been forgotten?  It was posted six months ago and
there's no sign that it was picked up.

The changes to drm_debug_enabled have impacted NV_DEBUG and NV_ATOMIC
and something needs to be fixed.  I posted a simpler patch a few weeks
ago, but maybe Jim's is better.

Re: [PATCH v6 32/57] nouveau: adapt NV_DEBUG, NV_ATOMIC to use DRM.debug

[jim.cromie]

On Mon, Mar 6, 2023 at 11:50 AM Timur Tabi <timur@kernel.org> wrote:
>
> On Sun, Sep 4, 2022 at 4:48 PM Jim Cromie <jim.cromie@gmail.com> wrote:
> >
> > These 2 macros used drm_debug_enabled() on DRM_UT_{DRIVER,ATOMIC}
> > respectively, replace those with drm_dbg_##cat invocations.
> >
> > this results in new class'd prdbg callsites:
> >
> > :#> grep nouveau /proc/dynamic_debug/control | grep class | wc
> >     116    1130   15584
> > :#> grep nouveau /proc/dynamic_debug/control | grep class | grep DRIVER | wc
> >      74     704    9709
> > :#> grep nouveau /proc/dynamic_debug/control | grep class | grep ATOMIC | wc
> >      31     307    4237
> > :#> grep nouveau /proc/dynamic_debug/control | grep class | grep KMS | wc
> >      11     119    1638
> >
> > the KMS entries are due to existing uses of drm_dbg_kms().
> >
> > Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
>
> Has this patch set been forgotten?  It was posted six months ago and
> there's no sign that it was picked up.

Not forgotten, but chicken-egg problems with initializing prdbgs/drm-dbgs
in drm.ko & dependent drivers pushed it down in priority.
I have a fix for them, which needs Jasons "lets use notifier-chain" patches,
which is now in Luis' modules-next.

After that fix lands, I can revisit this one.

> The changes to drm_debug_enabled have impacted NV_DEBUG and NV_ATOMIC
> and something needs to be fixed.  I posted a simpler patch a few weeks
> ago, but maybe Jim's is better.

I couldnt find it on lore, can you post a link ?

But I do recall something about chatty logs, caused by

#define drm_debug_enabled_instrumented(category)                        \
        ({                                                              \
                pr_debug("todo: is this frequent enough to optimize ?\n"); \
                drm_debug_enabled_raw(category);                        \
        })

If thats the case, it does seem to be frequent enough to silence.

Before you do so, could you turn on the "mfl" flags,
and count occurrences of each callsite ?

echo module nouveau +mfl > /proc/dynamic_debug/control

the numbers and duration of enablement would inform any optimization,
including those available in the subject patchset.

thanks,
Jim