[PATCH v5 00/33] DYNDBG: opt-in class'd debug for modules, use in drm.

[PATCH v5 00/33] DYNDBG: opt-in class'd debug for modules, use in drm.

[Jim Cromie]

Hi Jason, Greg, DRM-folk,

heres V5. Diffs vs V4:

  1st 9 have Jason's Ack
  10 is new: simple var cleanup
  11 new struct, to contain future addins. touches kernel/module/

  dyndbg-param callbacks moved to last (of dyndbg patches)
  they're where the uncertainty is,
  and the bulk of the API addition (class keyword is small)

  patches between the move are the guts of the "class foo" feature.
  exposure of feature is only via >control, until sysfs parts added
  
  DRM chunk:
  included here to see how patchwork's merge & test proceeds.
  categories -> classes re-work is unchanged - feels pretty solid.
  nouveau & LEVEL made some progress, still WIP.

  I left out tracefs bits for now.

UNCERTAINTIES / RFC:

1st is my "sharing" technique, across DRM's multi modules.  Its
literally duplicated decls, by each participating module, each adding
static data in its own special section.  I didn't try at all to shrink
or unify this any further.  There might be a perfect place to add a
single decl, but that quest will require a pony.

Sharing by class-names lacks the compiler support that varnames get;
"incomplete" enables will probably happen if one of the declarations
miss-spells one of the classnames.

That said, see the how-to below: stringifying va-args in the macro
would allow direct use of the enum-consts, and cc will insist that
those consts are defined, eliminating part of the un-support.

I could split the _BITS,_NUM handling out from _NAMES (ie split
drm.debug style patch); theres no user-demand for the _NAMES feature
ATM, and theres probably some legit API-bikeshedding to do.

PATCHSET DESCRIPTION

This patchset adds 'typed' "class FOO" support to dynamic-debug, where
'typed' means either DISJOINT_BITS, like drm_dbg(DRM_UT_CORE,..), or
LEVEL_NUM (like nouveau debug-levels).  Use it in DRM modules: core,
helpers, and in drivers i915, amdgpu, nouveau.

If a module is using class'd prdbgs (pr_debug_class, dev_dbg_class, or
adapted drm_dbg_<category>) or similar in its code, it can "opt in" to
allow dyndbg to manipulate those class'd prdebugs, by declaring in a
c-file:

 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");
			// how-to stringify __va_args inside the macro ?

By doing this, a module tells dyndbg that it:

   - is using class-ids [0..N] in prdbg callsites
     ( 0..N == DRM_UT_CORE..DRM_UT_DRMRES )
   - wants to refer to them by class-names [0..N]
   - is mapping those names to those class-ids
   - expects users to enable them via >control or >parameter/knob

Then, a user can enable the prdbgs by their class:

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

And with another 3-line bitmap param decl/init, wrapping the
drm_debug_classes var in a module-param-cb:

   :#> echo 0x1 > /sys/module/drm/parameters/debug

and optionally using classnames:

   :#> echo +DRM_UT_CORE,-DRM_UT_KMS \
	> /sys/module/drm/parameters/debug_cats

DYNAMIC_DEBUG gets:

struct _ddebug gets a new .class_id:5 field, big enough to represent
drm_debug_category (after squeezing).  It defaults to 31 for all
existing prdbgs.  class_id also supports verbose uses.

classmaps (as declared by macro above) are in their own linker
section, are loaded by kernel/module, and handled by add_module,
which attaches classmaps to their module's ddebug table.
     
ddebug_change() handles a class FOO query by validating that FOO is
known by each module in the loop.  The query is skipped unless the
module knows FOO, so no changes are possible w/o a good classname.

Without class FOO in a query/command, only ids=31 can be changed by
that query.  This protects all class'd prdbgs from changes by legacy
class-less user queries.

With this support, the module opt-in approach means that:

   - modules declare classnames they like, meaningful names: DRM_UT_*
     these are numbered [0..N]
   - modules call pr_debug_class(N, "fmt..",...)
     or drm_dbg(CAT, "fmt..",...) - same form.
   - class-id space, while limited:0-30, is private to each module
   - "class FOO" is only way to select a class'd prdbg
   - unrelated modules use 0..N separately, for different purposes.
   - modules "share" classnames by separate decls (uses of macro)
     all drm modules reuse the above declaration.
     then they respond together to a >control

4 CLASS_TYPES are defined; they split behavior on 2 factors:

   1. independent bits vs related:(X<Y) bits [0-N]
   2. input form: number/hex vs CSV-list: [+-]CLASS_NAMES
     
   DD_CLASS_TYPE_DISJOINT_BITS	independent bits, 0x1f input is clearest
   DD_CLASS_TYPE_LEVEL_NUM	(x<y), input is level, not bitvec

   DD_CLASS_TYPE_DISJOINT_NAMES	csv-list of independent +-CLASS_NAMEs
   DD_CLASS_TYPE_LEVEL_NAMES	csv-list of related +-CLASS_NAMEs, only 1 term needed

Splitting up behavior this way is safe, and flexible:

 - no bitmap-vs-level > sysknob ambiguity
   as was case when both were accepted on same knob
 - narrower interfaces
   uint is uint
 - can defer DISJOINT_NAMES handling, but keep the enums.
   it has no users ...
 - can later add 2 more ENUMS allowing both inputs
   in separate LEVEL_NUM & DISJOINT_BITS choices
   then authors choice if they want to accept mixed input
 - can enumerate "wierd" relations if needed
   DISJOINT_BITS|LEVEL_NUM should cover everything I can forsee
   but theres room for DD_CLASS_TYPE_STOCHASTIC (over the garage)

DISJOINT & LEVEL cover the space; 1st is independent, 2nd is related.
The relation could differ from (x<y), but atm I can't think of another
that makes any sensible distinction from (x<y).

Quick review of debug logging:

DRM is biggest use-case: 23 macros, issuing 10 exclusive categories of
messages, from ~5100 callsites, across core (drm, _*helpers), and 3+
drivers (Im working amdgpu, i915, more recently nouveau).  These mostly
flow to drm_debug_enabled(category) for a print/no decision.

nouveau has minimum direct use of the DRM.debug macros, but does use
pr_debug (in VMM iirc), and drm_debug_enabled() in ~50 places via
macros, and another ~50 iirc due to NOUVEAU_DEBUG_MMU=y

What nouveau has most of is log-levels: there are ~800 uses of them;
nvkm_(fatal|error|warn|info|debug|trace|spam), they all flow thru
nvkm_printk_.  Even excluding some levels as "always-on" and not
appropriate for dyndbg's extra resources and complexity, theres ~450
callsites.

A reported smattering of raw/adhoc debug code. all but unknown to me.

Like any debug logging, they're mostly off, and should have close to
0-off-cost.  This is what dyndbg (with/on jump-label) was made for.

Bottom line: in order to unify more potential (drm,etc) use-cases,
dyndbg needs to support both debug classification schemes:
RELATED/LEVEL_NUM and INDEPENDENT/DISJOINT_BITS.

This is rev3. rev2 is here:
https://lore.kernel.org/lkml/20220516225640.3102269-1-jim.cromie@gmail.com/

summary of diffs:

 - rebased on 5.19-rc6 to pick up kernel/module changes
 - tracfs bits now use __vstring, __vstr_assign, from S.Rostedt
 
 - 4 class-map-types - as outlined above
   now supports LEVEL_NUM semantics, WIP nouveau integration.
   v2 became the DISJOINT_BITS use case
   Lots of API-ish surface area here *RFC*

 - class-maps now in section("__dyndbg_classes")
   class FOO queries are available at earlyboot / module-load
   drop (un)?register_classes()

 - test-dynamic-debug module
   tests the 4 CLASS-TYPES
   good place to bikeshed / paintshop the API

 - nouveau - start poking - WIP
   NV_PRINT -> dev_dbg (creates 632 prdbgs, but not class'd)
   LEVEL_NUM classes declared to see how they "fit", unused yet.

Summary:

 - plenty of new stuff here.
 - plenty of new API surface area.
 - exposes CLASSNAMES to user, via control, >symbolic-sysknob

More on LEVEL_NUM:

dyndbg's class scheme is names-based, so even for LEVEL_NUM with
numeric input, there must be a "V0" name; a name with which to turn
off "V1".  And don't do 'pr_dbg_class(0,..)'.

LEVEL_NUM is an overlay on DISJOINT_BITS; the callback reads the input as a
level, and computes and applies the bitmap to enforce it.  Yes it
wastes "V0" bit.  That might matter if an author wanted many separate
verbose-knobs with a few levels each, but that seems fairly unlikely.

More importantly, it means that relative verbosity is not enforced at
the >control input; IOW this is allowed:

   :#> echo class V1 -p > /proc/dynamic_debug/control
   :#> echo class V3 +p > /proc/dynamic_debug/control

2nd line doesn't undo 1st, as it would if changed via sysfs-knob:

   :#> echo 3 > /sys/module/drm/parameters/debug

ISTM this is fine, the "relative" meaning is added at the interface,
where it presents to a user.  Doing otherwise means surgery to
ddebug_change, which seems unnecessary given an option.

CLASS NAMESPACE and DRM

The class namespace is flat and wide, so "V1" is a poor choice, other
than for demonstration (as in test_dynamic_debug module).  If every
module had a "V1", turning them all on would issue lots of unrelated
noise.

Instead, class DRM_UT_CORE has a name with a specific sub-system wide
(ie multi-module) meaning, and can (and should) be responded to by all
cooperating modules.

For DRM, this means 4-5 duplicate uses of DEFINE_DYNDBG_CLASSMAP, from
multiple drivers' "*_{drm,dev,main}.c" files; all of them agreeing on
the classnames, map-type and base.  Though repetitive, and a bit
fiddly when multiple classes share the module's id-space, it is
simple, and consistent with the "static struct foo = {INIT_expr}"
pattern used in the macro.  Im open to simpler ways, initializing an
extern sounded like a maze w/o cheese.

For core, drm_print.c has an additional task; it defines and
initializes the bitmap sysknob that converts bits to a query:

  static struct ddebug_classes_bitmap_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);

then the callback converts bit-toggles on input into something like:

  :#> echo class DRM_UT_KMS +p > control

which enables all drm_dbg_kms() callsites in all modules that declared
that classname as known.

NB: classmaps and classes_bitmap_params are different structs.  this
allows the former to be shared by 2 of latter, each toggling 'p' & 'T'
flags, to control output to syslog or tracelog independently.

NBB: while "V1" isnt a good classname, "EMERG" and and other
KERN-LEVEL names have a legacy.  That said, dyndbg shouldnt be
involved in EMERG actions.

NOUVEAU and multiple LEVEL_NUM knobs ?

One thing nouveau has that I havent yet grokked is 2|3 independent
verbose levels, in {,cli,sub}->debug (see subdev.h).  But Ive coded
them as 2 more macro invocations; using bases 10, 15 to avoid/respect
the 0-9 mapping of DRM.debug categories to those class-ids.

With this, the drm subsystem uses 20/31 of its class-id range, perhaps
63 is better, despite the cumbersome 0x-64bit interface.  Note that
the sysfs-knobs do not expose the base/offset (its an inward-facing
.class_id offset); each sysfs-knob gets its own 0..N bitmap, the base
maps it to the 0..30 subrange allocated (manually, via the base arg to
macro) for this class-map.

anyway, heres how `modprobe nouveau` goes with dynamic_debug.verbose=3

[86512.693954] dyndbg: class[0]: module:nouveau base:15 len:5 ty:1
[86512.693958] dyndbg:  15: 0 NV_SUBDEV_DBG_OFF		# aka V0
[86512.693959] dyndbg:  16: 1 NV_SUBDEV_DBG_INFO
[86512.693960] dyndbg:  17: 2 NV_SUBDEV_DBG_DEBUG
[86512.693960] dyndbg:  18: 3 NV_SUBDEV_DBG_TRACE
[86512.693960] dyndbg:  19: 4 NV_SUBDEV_DBG_SPAM
[86512.693961] dyndbg: class[1]: module:nouveau base:10 len:5 ty:1
[86512.693961] dyndbg:  10: 0 NV_CLI_DBG_OFF
[86512.693962] dyndbg:  11: 1 NV_CLI_DBG_INFO
[86512.693962] dyndbg:  12: 2 NV_CLI_DBG_DEBUG
[86512.693963] dyndbg:  13: 3 NV_CLI_DBG_TRACE
[86512.693963] dyndbg:  14: 4 NV_CLI_DBG_SPAM
[86512.693963] dyndbg: class[2]: module:nouveau base:0 len:10 ty:0
[86512.693964] dyndbg:  0: 0 DRM_UT_CORE
[86512.693964] dyndbg:  1: 1 DRM_UT_DRIVER
[86512.693965] dyndbg:  2: 2 DRM_UT_KMS
[86512.693965] dyndbg:  3: 3 DRM_UT_PRIME
[86512.693965] dyndbg:  4: 4 DRM_UT_ATOMIC
[86512.693966] dyndbg:  5: 5 DRM_UT_VBL
[86512.693966] dyndbg:  6: 6 DRM_UT_STATE
[86512.693966] dyndbg:  7: 7 DRM_UT_LEASE
[86512.693967] dyndbg:  8: 8 DRM_UT_DP
[86512.693967] dyndbg:  9: 9 DRM_UT_DRMRES
[86512.693968] dyndbg: module:nouveau attached 3 classes
[86512.693968] dyndbg: 632 debug prints in module nouveau

They are not yet wired by class; the nv-printks are using dev_dbg for
now, so they can be enabled with standard selections (module, func,
etc).

DYNDBG API

I added __pr_debug_cls to make things testable, I wanted to keep it
private/un-api, because drm already has drm_dbg_<cat>(cat, fmt..), and
that seemed a pretty good model to follow: enums with strong names for
class_id constants, and same names for classes.

   ie: __pr_debug_cls(DRM_UT_KMS, "Whats the Matter with KMS: %s\n", reason);

But now nouveau probably wants/needs it, perhaps others too.

  pr_dbg_cls / dev_dbg_cls ?  class or debug spelled out ? 

MORE TESTING with DRM & TRACEFS

Most dev & testing has been on virtme, with test-dynamic-debug module
doing an api-validation-demonstration.  The test module proves
multiple sysknobs, but cannot prove real multi-module sharing of the
class-name space.  The DRM.debug adaptation must (and does) do that.

Now Im running on real gpu/drm hw; on both an amdgpu desktop, and this
amdgpu+nouveau laptop.  Its stable enough to type on, browse, build
more kernels, etc.

:#> uname -r
5.18.0-f2-00038-g61d300083196
:#> wc /proc/dynamic_debug/control 
11554 95556 1442827 /proc/dynamic_debug/control
:#> lsmod | grep drm
drm_buddy              20480  1 i915
drm_ttm_helper         16384  2 amdgpu,nouveau
ttm                    86016  4 amdgpu,drm_ttm_helper,i915,nouveau
drm_dp_helper         184320  3 amdgpu,i915,nouveau
drm_kms_helper        208896  6 drm_dp_helper,amdgpu,i915,nouveau
drm                   655360  16 gpu_sched,drm_dp_helper,drm_kms_helper,drm_buddy,amdgpu,drm_ttm_helper,i915,ttm,nouveau
cec                    49152  2 drm_dp_helper,i915

I've never turned on DRM.debug in frustration (or curiousity until
recently); I dunno what normal traffic looks like.  So I wrote a
script to toggle each category: on/off for 1 sec, so I could 'more'
thru the output to see the partitioned streams.

Different runs (of '10' sec of active tracing) produce between 330-3500
lines of logging, depending upon mousing/screen activity.  Heres a bit
of a many-window-select run: `wc trace` gives "size" of the category's stream.

:#> trc_classes 
12 /sys/kernel/tracing/trace
doing class DRM_UT_CORE +/- T   1394 13941 141614 /sys/kernel/tracing/trace
doing class DRM_UT_DRIVER +/- T   1396 13959 141816 /sys/kernel/tracing/trace
doing class DRM_UT_KMS +/- T   1482 14521 148246 /sys/kernel/tracing/trace
doing class DRM_UT_PRIME +/- T   1484 14539 148446 /sys/kernel/tracing/trace
doing class DRM_UT_ATOMIC +/- T   2984 31658 396064 /sys/kernel/tracing/trace
doing class DRM_UT_VBL +/- T   3411 37321 449848 /sys/kernel/tracing/trace
doing class DRM_UT_STATE +/- T   3413 37339 450048 /sys/kernel/tracing/trace
doing class DRM_UT_LEASE +/- T   3415 37357 450248 /sys/kernel/tracing/trace
doing class DRM_UT_DP +/- T   3417 37375 450442 /sys/kernel/tracing/trace
doing class DRM_UT_DRMRES +/- T   3419 37393 450644 /sys/kernel/tracing/trace

and some mid-run output from a quiet run, with less repetition.

            bash-96790   [006] ..... 410237.432255: tracing_mark_write: doing class DRM_UT_DRIVER +T
            bash-96790   [006] ..... 410238.610319: tracing_mark_write: doing class DRM_UT_DRIVER -T
            bash-96790   [006] ..... 410239.776285: tracing_mark_write: doing class DRM_UT_KMS +T
     gnome-shell-2101    [003] ..... 410239.923029: drm_debug: [FB:98]
  kworker/u32:10-367584  [010] ..... 410239.924627: drm_debug: Allow idle optimizations (MALL): 0
   kworker/u32:0-364714  [008] ..... 410239.935126: drm_debug: Allow idle optimizations (MALL): 1
     gnome-shell-2101    [003] ..... 410240.527186: drm_debug: [FB:100]
   kworker/u32:0-364714  [008] ..... 410240.528686: drm_debug: Allow idle optimizations (MALL): 0
  kworker/u32:10-367584  [010] ..... 410240.539378: drm_debug: Allow idle optimizations (MALL): 1
            bash-96790   [006] ..... 410240.957921: tracing_mark_write: doing class DRM_UT_KMS -T
            bash-96790   [006] ..... 410242.199120: tracing_mark_write: doing class DRM_UT_PRIME +T
            bash-96790   [006] ..... 410243.301988: tracing_mark_write: doing class DRM_UT_PRIME -T
            bash-96790   [006] ..... 410244.416400: tracing_mark_write: doing class DRM_UT_ATOMIC +T
     gnome-shell-2101    [003] ..... 410244.653372: drm_devdbg: cat:4, (0xffff8f26c173de00:0000:06:00.0)[UNSAFE-MEMORY] Allocated atomic state 000000001f1e6cb6
     gnome-shell-2101    [003] ..... 410244.653381: drm_devdbg: cat:4, (0xffff8f26c173de00:0000:06:00.0)[UNSAFE-MEMORY] Added [PLANE:55:plane-3] 00000000785ae904 state to 000000001f1e6cb6
     gnome-shell-2101    [003] ..... 410244.653384: drm_devdbg: cat:4, (0xffff8f26c173de00:0000:06:00.0)[UNSAFE-MEMORY] Added [CRTC:67:crtc-0] 00000000b06ca618 state to 000000001f1e6cb6
     gnome-shell-2101    [003] ..... 410244.653389: drm_devdbg: cat:4, (0xffff8f26c173de00:0000:06:00.0)[UNSAFE-MEMORY] Set [FB:98] for [PLANE:55:plane-3] state 00000000785ae904
     gnome-shell-2101    [003] ..... 410244.653392: drm_devdbg: cat:4, (0xffff8f26c173de00:0000:06:00.0)[UNSAFE-MEMORY] checking 000000001f1e6cb6
     gnome-shell-2101    [003] ..... 410244.653407: drm_devdbg: cat:4, (0xffff8f26c173de00:0000:06:00.0)[UNSAFE-MEMORY] committing 000000001f1e6cb6 nonblocking
   kworker/u32:0-364714  [010] ..... 410244.653729: drm_debug: amdgpu_crtc id:0 crtc_state_flags: enable:1, active:1, planes_changed:1, mode_changed:0,active_changed:0,connectors_changed:0
   kworker/u32:0-364714  [010] ..... 410244.654642: drm_debug: plane: id=3 dcc_en=0

a few things to note in the trace output:

. the event-name: drm_(debug|devdbg) is not very informative

. drm_devdbg fmt has cat:%d, it could be the classname, but that should
  replace event-name, not supplement it. this pertains to drm_debug too.

. drm_devdbg has lots of (dev-info), that could be optional on a new flag(s)


If anyone wants to repeat the above with the patchset, the .rc file follows:

events_3() {
    local a=$1
    local b=$2
    local c=$3
    echo $a > /sys/kernel/tracing/events/dyndbg/enable
    # avoid drm_vblank*, its noisy
    echo $b > /sys/kernel/tracing/events/drm/drm_debug/enable
    echo $c > /sys/kernel/tracing/events/drm/drm_devdbg/enable
}

flags_class() {
    local flgs=$1;
    local cls=$2;
    echo class $cls $flgs > /proc/dynamic_debug/control
}

# turn on each DRM_UT_* for 1 second each.
# kinda shows relative traffic of each category
# separated into blocks to get flavor of each

drm_classes() {
    local flgs=$1
    [ -z $flgs ] && flgs="p"

    #echo > /sys/kernel/tracing/trace
    #wc /sys/kernel/tracing/trace

    for cls in 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;
    do
	echo -n doing class $cls "  "

	echo doing class $cls +$flgs
	sleep .1
	flags_class +$flgs $cls
	sleep 1
	
	echo doing class $cls -$flgs
	sleep .1
	flags_class -$flgs $cls
	sleep 1
	
	#wc /sys/kernel/tracing/trace
    done
}

# like above but with T flag, and markers, trace/enable
trc_classes() {
    local flgs=$1
    [ -z $flgs ] && flgs="T"

    echo > /sys/kernel/tracing/trace
    wc -l /sys/kernel/tracing/trace

    events_3 1 1 1
    for cls in 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;
    do
	echo -n doing class $cls +/- $flgs "  "

	echo doing class $cls +$flgs > /sys/kernel/tracing/trace_marker
	sleep .1
	flags_class +$flgs $cls
	sleep 1
	
	echo doing class $cls -$flgs > /sys/kernel/tracing/trace_marker
	sleep .1
	flags_class -$flgs $cls
	sleep 1
	
	wc /sys/kernel/tracing/trace

    done
    events_3 0 0 0
}


Jim Cromie (33):

1st, a group of "cleanups"

  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 local vars in ddebug_init
  dyndbg: create and use struct _ddebug_info

class FOO support  

  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

add dyndbg-class-param support

  dyndbg: add drm.debug style (drm/parameters/debug) bitmap support
  dyndbg: test DECLARE_DYNDBG_CLASSMAP, sysfs nodes

drm.debug adaptation

  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-LEVEL_NUM integration: WIP/exploratory.

  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

 .../admin-guide/dynamic-debug-howto.rst       | 246 +++++-----
 MAINTAINERS                                   |   2 +
 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                   |  48 +-
 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/vmlinux.lds.h             |   3 +
 include/drm/drm_print.h                       |  85 +++-
 include/linux/dynamic_debug.h                 | 176 +++++--
 kernel/module/internal.h                      |   4 +-
 kernel/module/main.c                          |  20 +-
 lib/Kconfig.debug                             |  10 +
 lib/Makefile                                  |   1 +
 lib/dynamic_debug.c                           | 450 +++++++++++++++---
 lib/test_dynamic_debug.c                      | 165 +++++++
 23 files changed, 1099 insertions(+), 269 deletions(-)
 create mode 100644 lib/test_dynamic_debug.c

-- 
2.37.1

[PATCH v5 01/33] 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
Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
Acked-by: Jason Baron <jbaron@akamai.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",
-- 
2.37.1

[PATCH v5 02/33] 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
Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
Acked-by: Jason Baron <jbaron@akamai.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");
-- 
2.37.1

[PATCH v5 03/33] dyndbg: show both old and new in change-info

[Jim Cromie]

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

no functional change.

Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
Acked-by: Jason Baron <jbaron@akamai.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);
-- 
2.37.1

[PATCH v5 04/33] 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.

Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
Acked-by: Jason Baron <jbaron@akamai.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);
-- 
2.37.1

[PATCH v5 05/33] 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"

Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
Acked-by: Jason Baron <jbaron@akamai.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];
 }
-- 
2.37.1

[PATCH v5 06/33] 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"

Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
Acked-by: Jason Baron <jbaron@akamai.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;
-- 
2.37.1

[PATCH v5 07/33] 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
Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
Acked-by: Jason Baron <jbaron@akamai.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;
 }
-- 
2.37.1

[PATCH v5 08/33] 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

Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
Acked-by: Jason Baron <jbaron@akamai.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 64379c699903..a14fc4b6a10b 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -7093,6 +7093,8 @@ 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 2e24db4bff19..ca5978e1d18a 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -2529,6 +2529,16 @@ 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 f99bf61f8bbc..9c316df868de 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -82,6 +82,7 @@ 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");
-- 
2.37.1

[PATCH v5 09/33] 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")
Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
Acked-by: Jason Baron <jbaron@akamai.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)
-- 
2.37.1

[PATCH v5 10/33] dyndbg: cleanup local vars in ddebug_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
    this allows '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.
-- 
2.37.1

[PATCH v5 11/33] dyndbg: create and use struct _ddebug_info

[Jim Cromie]

this new struct gathers the linker provided vectors/sections:

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

Use it as follows:

In lib/dynamic_debug.c:

Alter ddebug_add_module() params-list, replacing descriptor-table and
its length with a single _ddebug_info object containing them.  This
future-proofs the function against the looming addition of class-map
info, for either the builtin module set, or the loaded module.

In dynamic_debug_init(): add & initialize an auto struct _ddebug_info
var, and use it like a cursor / multi-part iterator.  Re-initialize
the var's component values before each call to ddebug_add_module().
This gives us the inch-worm walk thru the modules in the built-in
__dyndbgs data section.

In kernel/module/{main.c,internal.h}:

Embed a struct _ddebug_info into struct load_info, replacing the 2 fields it
contains.  Populate its members in find_module_sections.

Also adjust dynamic_debug_setup/remove() to match the change to
ddebug_add_module().

Note: this adds an include dynamic_debug, and might be prone to
include loops, since its also smuggled in by printk.h.  Nothing has
puked in robot-land.

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 ec104c2950c3..ce42b5b8b4da 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 0548151dd933..cfe10356793d 100644
--- a/kernel/module/main.c
+++ b/kernel/module/main.c
@@ -1593,16 +1593,16 @@ 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);
 }
 
@@ -2093,8 +2093,8 @@ 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;
 }
@@ -2783,7 +2783,7 @@ 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);
@@ -2845,7 +2845,7 @@ 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..457ce936191a 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, 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, modname);
 	if (ret)
 		goto out_err;
 
-- 
2.37.1

[PATCH v5 12/33] 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 field: struct _ddebug.class_id:5.

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

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

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

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

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

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

No behavior change.

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

diff --git a/include/linux/dynamic_debug.h b/include/linux/dynamic_debug.h
index 6a2001250da1..b6803f7e818f 100644
--- a/include/linux/dynamic_debug.h
+++ b/include/linux/dynamic_debug.h
@@ -6,6 +6,8 @@
 #include <linux/jump_label.h>
 #endif
 
+#include <linux/build_bug.h>
+
 /*
  * An instance of this structure is created in a special
  * ELF section at every dynamic debug callsite.  At runtime,
@@ -21,6 +23,9 @@ struct _ddebug {
 	const char *filename;
 	const char *format;
 	unsigned int lineno:18;
+#define CLS_BITS 5
+	unsigned int class_id:CLS_BITS;
+#define _DPRINTK_CLASS_DFLT		((1 << CLS_BITS) - 1)
 	/*
 	 * The flags field controls the behaviour at the callsite.
 	 * The bits here are changed dynamically when the user
@@ -88,7 +93,7 @@ void __dynamic_ibdev_dbg(struct _ddebug *descriptor,
 			 const struct ib_device *ibdev,
 			 const char *fmt, ...);
 
-#define DEFINE_DYNAMIC_DEBUG_METADATA(name, fmt)		\
+#define DEFINE_DYNAMIC_DEBUG_METADATA_CLS(name, cls, fmt)	\
 	static struct _ddebug  __aligned(8)			\
 	__section("__dyndbg") name = {				\
 		.modname = KBUILD_MODNAME,			\
@@ -97,8 +102,14 @@ void __dynamic_ibdev_dbg(struct _ddebug *descriptor,
 		.format = (fmt),				\
 		.lineno = __LINE__,				\
 		.flags = _DPRINTK_FLAGS_DEFAULT,		\
+		.class_id = cls,				\
 		_DPRINTK_KEY_INIT				\
-	}
+	};							\
+	BUILD_BUG_ON_MSG(cls > _DPRINTK_CLASS_DFLT,		\
+			 "classid value overflow")
+
+#define DEFINE_DYNAMIC_DEBUG_METADATA(name, fmt)		\
+	DEFINE_DYNAMIC_DEBUG_METADATA_CLS(name, _DPRINTK_CLASS_DFLT, fmt)
 
 #ifdef CONFIG_JUMP_LABEL
 
@@ -129,17 +140,34 @@ void __dynamic_ibdev_dbg(struct _ddebug *descriptor,
 
 #endif /* CONFIG_JUMP_LABEL */
 
-#define __dynamic_func_call(id, fmt, func, ...) do {	\
-	DEFINE_DYNAMIC_DEBUG_METADATA(id, fmt);		\
-	if (DYNAMIC_DEBUG_BRANCH(id))			\
-		func(&id, ##__VA_ARGS__);		\
-} while (0)
-
-#define __dynamic_func_call_no_desc(id, fmt, func, ...) do {	\
-	DEFINE_DYNAMIC_DEBUG_METADATA(id, fmt);			\
+/*
+ * Factory macros: ($prefix)dynamic_func_call($suffix)
+ *
+ * Lower layer (with __ prefix) gets the callsite metadata, and wraps
+ * the func inside a debug-branch/static-key construct.  Upper layer
+ * (with _ prefix) does the UNIQUE_ID once, so that lower can ref the
+ * name/label multiple times, and tie the elements together.
+ * Multiple flavors:
+ * (|_cls):	adds in _DPRINT_CLASS_DFLT as needed
+ * (|_no_desc):	former gets callsite descriptor as 1st arg (for prdbgs)
+ */
+#define __dynamic_func_call_cls(id, cls, fmt, func, ...) do {	\
+	DEFINE_DYNAMIC_DEBUG_METADATA_CLS(id, cls, fmt);	\
 	if (DYNAMIC_DEBUG_BRANCH(id))				\
-		func(__VA_ARGS__);				\
+		func(&id, ##__VA_ARGS__);			\
 } while (0)
+#define __dynamic_func_call(id, fmt, func, ...)				\
+	__dynamic_func_call_cls(id, _DPRINTK_CLASS_DFLT, fmt,		\
+				func, ##__VA_ARGS__)
+
+#define __dynamic_func_call_cls_no_desc(id, cls, fmt, func, ...) do {	\
+	DEFINE_DYNAMIC_DEBUG_METADATA_CLS(id, cls, fmt);		\
+	if (DYNAMIC_DEBUG_BRANCH(id))					\
+		func(__VA_ARGS__);					\
+} while (0)
+#define __dynamic_func_call_no_desc(id, fmt, func, ...)			\
+	__dynamic_func_call_cls_no_desc(id, _DPRINTK_CLASS_DFLT,	\
+					fmt, func, ##__VA_ARGS__)
 
 /*
  * "Factory macro" for generating a call to func, guarded by a
@@ -149,22 +177,33 @@ void __dynamic_ibdev_dbg(struct _ddebug *descriptor,
  * the varargs. Note that fmt is repeated in invocations of this
  * macro.
  */
+#define _dynamic_func_call_cls(cls, fmt, func, ...)			\
+	__dynamic_func_call_cls(__UNIQUE_ID(ddebug), cls, fmt, func, ##__VA_ARGS__)
 #define _dynamic_func_call(fmt, func, ...)				\
-	__dynamic_func_call(__UNIQUE_ID(ddebug), fmt, func, ##__VA_ARGS__)
+	_dynamic_func_call_cls(_DPRINTK_CLASS_DFLT, fmt, func, ##__VA_ARGS__)
+
 /*
  * A variant that does the same, except that the descriptor is not
  * passed as the first argument to the function; it is only called
  * with precisely the macro's varargs.
  */
-#define _dynamic_func_call_no_desc(fmt, func, ...)	\
-	__dynamic_func_call_no_desc(__UNIQUE_ID(ddebug), fmt, func, ##__VA_ARGS__)
+#define _dynamic_func_call_cls_no_desc(cls, fmt, func, ...)		\
+	__dynamic_func_call_cls_no_desc(__UNIQUE_ID(ddebug), cls, fmt,	\
+					func, ##__VA_ARGS__)
+#define _dynamic_func_call_no_desc(fmt, func, ...)			\
+	_dynamic_func_call_cls_no_desc(_DPRINTK_CLASS_DFLT, fmt,	\
+				       func, ##__VA_ARGS__)
+
+#define dynamic_pr_debug_cls(cls, fmt, ...)				\
+	_dynamic_func_call_cls(cls, fmt, __dynamic_pr_debug,		\
+			   pr_fmt(fmt), ##__VA_ARGS__)
 
 #define dynamic_pr_debug(fmt, ...)				\
-	_dynamic_func_call(fmt,	__dynamic_pr_debug,		\
+	_dynamic_func_call(fmt, __dynamic_pr_debug,		\
 			   pr_fmt(fmt), ##__VA_ARGS__)
 
 #define dynamic_dev_dbg(dev, fmt, ...)				\
-	_dynamic_func_call(fmt,__dynamic_dev_dbg, 		\
+	_dynamic_func_call(fmt, __dynamic_dev_dbg, 		\
 			   dev, fmt, ##__VA_ARGS__)
 
 #define dynamic_netdev_dbg(dev, fmt, ...)			\
-- 
2.37.1

[PATCH v5 13/33] 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 b6803f7e818f..cb4696c91901 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>
-- 
2.37.1

[PATCH v5 14/33] dyndbg: add DECLARE_DYNDBG_CLASSMAP macro

[Jim Cromie]

With 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)

   :#> 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_id space, and only known class-names
will be authorized for a manipulation.  Only DRM stuff should know 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 a 'orphan' warning which we
handle in next commit.  The struct attributes are necessary:
__aligned(8) stopped null-ptr derefs (why?), __used is needed by drm
drivers, which declare class-maps, but don't also declare a
sysfs-param, and thus dont ref the classmap; __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 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 by necessity - _NAMES feature is extra.
---
 include/linux/dynamic_debug.h | 56 +++++++++++++++++++++++++++++++++++
 1 file changed, 56 insertions(+)

diff --git a/include/linux/dynamic_debug.h b/include/linux/dynamic_debug.h
index cb4696c91901..71cdc8612257 100644
--- a/include/linux/dynamic_debug.h
+++ b/include/linux/dynamic_debug.h
@@ -56,6 +56,62 @@ 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.  Model user
+	 * would be /sys/module/drm/parameters/debug_categories.
+	 */
+	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;
-- 
2.37.1

[PATCH v5 15/33] 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 71cdc8612257..46ed10682e87 100644
--- a/include/linux/dynamic_debug.h
+++ b/include/linux/dynamic_debug.h
@@ -115,7 +115,9 @@ 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 cfe10356793d..f68f331c867d 100644
--- a/kernel/module/main.c
+++ b/kernel/module/main.c
@@ -2095,6 +2095,8 @@ 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 457ce936191a..0d6cb6b258bd 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
-- 
2.37.1

[PATCH v5 16/33] 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.

Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
---
 lib/dynamic_debug.c | 34 +++++++++++++++++++++++++++++++++-
 1 file changed, 33 insertions(+), 1 deletion(-)

diff --git a/lib/dynamic_debug.c b/lib/dynamic_debug.c
index 0d6cb6b258bd..a3ace5866f1b 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.
@@ -953,6 +979,12 @@ static int __ddebug_add_module(struct _ddebug_info *di, unsigned int base,
 
 	INIT_LIST_HEAD(&dt->link);
 
+	INIT_LIST_HEAD(&dt->link);
+	INIT_LIST_HEAD(&dt->maps);
+
+	if (classes && num_classes)
+		ddebug_attach_module_classes(dt, classes, num_classes);
+
 	mutex_lock(&ddebug_lock);
 	list_add_tail(&dt->link, &ddebug_tables);
 	mutex_unlock(&ddebug_lock);
-- 
2.37.1

[PATCH v5 17/33] 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 a3ace5866f1b..eb410b412f0d 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;
 }
-- 
2.37.1

[PATCH v5 18/33] 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
-- 
2.37.1

[PATCH v5 19/33] 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.
-- 
2.37.1

[PATCH v5 20/33] 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 union of &ulong bits, level; which points to user module's ulong
storing the module's debug-state.  By ref'g the client's bit-state
_var, code coordinates with existing code (like drm_debug_enabled)
which uses it, so existing works unchanged.  Changing 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 standard _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,
and is done by 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.
---
 include/linux/dynamic_debug.h |  20 ++++
 lib/dynamic_debug.c           | 218 +++++++++++++++++++++++++++++++++-
 2 files changed, 234 insertions(+), 4 deletions(-)

diff --git a/include/linux/dynamic_debug.h b/include/linux/dynamic_debug.h
index 46ed10682e87..956614a208a4 100644
--- a/include/linux/dynamic_debug.h
+++ b/include/linux/dynamic_debug.h
@@ -120,6 +120,14 @@ struct _ddebug_info {
 	unsigned int num_classes;
 };
 
+struct ddebug_class_param {
+	union { unsigned long *bits;
+		unsigned long *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);
@@ -279,6 +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),		\
@@ -325,6 +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 eb410b412f0d..c41e22d850e0 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, "%ld\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)
@@ -1037,13 +1249,11 @@ static int __ddebug_add_module(struct _ddebug_info *di, unsigned int base,
 	dt->ddebugs = di->descs;
 	dt->num_ddebugs = di->num_descs;
 
-	INIT_LIST_HEAD(&dt->link);
-
 	INIT_LIST_HEAD(&dt->link);
 	INIT_LIST_HEAD(&dt->maps);
 
-	if (classes && num_classes)
-		ddebug_attach_module_classes(dt, classes, num_classes);
+	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);
-- 
2.37.1

[PATCH v5 21/33] 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);
-- 
2.37.1

[PATCH v5 22/33] 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));
 }
 
 /*
-- 
2.37.1

[PATCH v5 23/33] 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 8890300766a5..183d604559fe 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"
@@ -183,6 +185,18 @@ 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 e7c22c2ca90c..c8a4076aa4ab 100644
--- a/drivers/gpu/drm/display/drm_dp_helper.c
+++ b/drivers/gpu/drm/display/drm_dp_helper.c
@@ -29,6 +29,7 @@
 #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>
@@ -38,6 +39,18 @@
 
 #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 b632825654a9..73e16fc0659f 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 701fbc98afa0..aa4e43b59daa 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, ...
-- 
2.37.1

[PATCH v5 24/33] 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, ...)				\
-- 
2.37.1

[PATCH v5 25/33] 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 f65656df3619..aad2ac5641c1 100644
--- a/drivers/gpu/drm/Kconfig
+++ b/drivers/gpu/drm/Kconfig
@@ -50,6 +50,18 @@ 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_DEBUG_SELFTEST
 	tristate "kselftests for DRM"
 	depends on DRM
diff --git a/drivers/gpu/drm/Makefile b/drivers/gpu/drm/Makefile
index 15fe3163f822..272de137d207 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 */
 
-- 
2.37.1

[PATCH v5 26/33] 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>
 
-- 
2.37.1

[PATCH v5 27/33] 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
-- 
2.37.1

[PATCH v5 28/33] 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
  *
-- 
2.37.1

[PATCH v5 29/33] 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);
 
-- 
2.37.1

[PATCH v5 30/33] 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 */
-- 
2.37.1

[PATCH v5 31/33] 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)
-- 
2.37.1

[PATCH v5 32/33] 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 b2a970aa9bf4..f266cd6b0405 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>
@@ -264,13 +265,16 @@ 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)
-- 
2.37.1

[PATCH v5 33/33] 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);
 }
 
-- 
2.37.1

Re: [PATCH v5 19/33] doc-dyndbg: edit dynamic-debug-howto for brevity, audience

[Bagas Sanjaya]

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On Fri, Aug 05, 2022 at 03:53:41PM -0600, Jim Cromie wrote:
> 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>
> 

The documentation LGTM (no new warnings).

Reviewed-by: Bagas Sanjaya <bagasdotme@gmail.com>

-- 
An old man doll... just what I always wanted! - Clara

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Re: [PATCH v5 00/33] DYNDBG: opt-in class'd debug for modules, use in drm.

[Daniel Vetter]

[Catching up on mails]

Did you see the feedback form Steven from tracing side of things? Does
this version have that taken into account already?

I think once we have that and acks from dyndbg maintainers then I think we
should just land this and polish from there? Maybe some acks from drm
drivrer folks (cros people where once interested), but otherwise I'm a bit
afraid this might be stuck in limbo too much for too long and we just need
to get going :-/
-Daniel


On Fri, Aug 05, 2022 at 03:53:22PM -0600, Jim Cromie wrote:
> Hi Jason, Greg, DRM-folk,
> 
> heres V5. Diffs vs V4:
> 
>   1st 9 have Jason's Ack
>   10 is new: simple var cleanup
>   11 new struct, to contain future addins. touches kernel/module/
> 
>   dyndbg-param callbacks moved to last (of dyndbg patches)
>   they're where the uncertainty is,
>   and the bulk of the API addition (class keyword is small)
> 
>   patches between the move are the guts of the "class foo" feature.
>   exposure of feature is only via >control, until sysfs parts added
>   
>   DRM chunk:
>   included here to see how patchwork's merge & test proceeds.
>   categories -> classes re-work is unchanged - feels pretty solid.
>   nouveau & LEVEL made some progress, still WIP.
> 
>   I left out tracefs bits for now.
> 
> UNCERTAINTIES / RFC:
> 
> 1st is my "sharing" technique, across DRM's multi modules.  Its
> literally duplicated decls, by each participating module, each adding
> static data in its own special section.  I didn't try at all to shrink
> or unify this any further.  There might be a perfect place to add a
> single decl, but that quest will require a pony.
> 
> Sharing by class-names lacks the compiler support that varnames get;
> "incomplete" enables will probably happen if one of the declarations
> miss-spells one of the classnames.
> 
> That said, see the how-to below: stringifying va-args in the macro
> would allow direct use of the enum-consts, and cc will insist that
> those consts are defined, eliminating part of the un-support.
> 
> I could split the _BITS,_NUM handling out from _NAMES (ie split
> drm.debug style patch); theres no user-demand for the _NAMES feature
> ATM, and theres probably some legit API-bikeshedding to do.
> 
> PATCHSET DESCRIPTION
> 
> This patchset adds 'typed' "class FOO" support to dynamic-debug, where
> 'typed' means either DISJOINT_BITS, like drm_dbg(DRM_UT_CORE,..), or
> LEVEL_NUM (like nouveau debug-levels).  Use it in DRM modules: core,
> helpers, and in drivers i915, amdgpu, nouveau.
> 
> If a module is using class'd prdbgs (pr_debug_class, dev_dbg_class, or
> adapted drm_dbg_<category>) or similar in its code, it can "opt in" to
> allow dyndbg to manipulate those class'd prdebugs, by declaring in a
> c-file:
> 
>  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");
> 			// how-to stringify __va_args inside the macro ?
> 
> By doing this, a module tells dyndbg that it:
> 
>    - is using class-ids [0..N] in prdbg callsites
>      ( 0..N == DRM_UT_CORE..DRM_UT_DRMRES )
>    - wants to refer to them by class-names [0..N]
>    - is mapping those names to those class-ids
>    - expects users to enable them via >control or >parameter/knob
> 
> Then, a user can enable the prdbgs by their class:
> 
>    :#> echo class DRM_UT_KMS +p > /proc/dynamic_debug/control
> 
> And with another 3-line bitmap param decl/init, wrapping the
> drm_debug_classes var in a module-param-cb:
> 
>    :#> echo 0x1 > /sys/module/drm/parameters/debug
> 
> and optionally using classnames:
> 
>    :#> echo +DRM_UT_CORE,-DRM_UT_KMS \
> 	> /sys/module/drm/parameters/debug_cats
> 
> DYNAMIC_DEBUG gets:
> 
> struct _ddebug gets a new .class_id:5 field, big enough to represent
> drm_debug_category (after squeezing).  It defaults to 31 for all
> existing prdbgs.  class_id also supports verbose uses.
> 
> classmaps (as declared by macro above) are in their own linker
> section, are loaded by kernel/module, and handled by add_module,
> which attaches classmaps to their module's ddebug table.
>      
> ddebug_change() handles a class FOO query by validating that FOO is
> known by each module in the loop.  The query is skipped unless the
> module knows FOO, so no changes are possible w/o a good classname.
> 
> Without class FOO in a query/command, only ids=31 can be changed by
> that query.  This protects all class'd prdbgs from changes by legacy
> class-less user queries.
> 
> With this support, the module opt-in approach means that:
> 
>    - modules declare classnames they like, meaningful names: DRM_UT_*
>      these are numbered [0..N]
>    - modules call pr_debug_class(N, "fmt..",...)
>      or drm_dbg(CAT, "fmt..",...) - same form.
>    - class-id space, while limited:0-30, is private to each module
>    - "class FOO" is only way to select a class'd prdbg
>    - unrelated modules use 0..N separately, for different purposes.
>    - modules "share" classnames by separate decls (uses of macro)
>      all drm modules reuse the above declaration.
>      then they respond together to a >control
> 
> 4 CLASS_TYPES are defined; they split behavior on 2 factors:
> 
>    1. independent bits vs related:(X<Y) bits [0-N]
>    2. input form: number/hex vs CSV-list: [+-]CLASS_NAMES
>      
>    DD_CLASS_TYPE_DISJOINT_BITS	independent bits, 0x1f input is clearest
>    DD_CLASS_TYPE_LEVEL_NUM	(x<y), input is level, not bitvec
> 
>    DD_CLASS_TYPE_DISJOINT_NAMES	csv-list of independent +-CLASS_NAMEs
>    DD_CLASS_TYPE_LEVEL_NAMES	csv-list of related +-CLASS_NAMEs, only 1 term needed
> 
> Splitting up behavior this way is safe, and flexible:
> 
>  - no bitmap-vs-level > sysknob ambiguity
>    as was case when both were accepted on same knob
>  - narrower interfaces
>    uint is uint
>  - can defer DISJOINT_NAMES handling, but keep the enums.
>    it has no users ...
>  - can later add 2 more ENUMS allowing both inputs
>    in separate LEVEL_NUM & DISJOINT_BITS choices
>    then authors choice if they want to accept mixed input
>  - can enumerate "wierd" relations if needed
>    DISJOINT_BITS|LEVEL_NUM should cover everything I can forsee
>    but theres room for DD_CLASS_TYPE_STOCHASTIC (over the garage)
> 
> DISJOINT & LEVEL cover the space; 1st is independent, 2nd is related.
> The relation could differ from (x<y), but atm I can't think of another
> that makes any sensible distinction from (x<y).
> 
> Quick review of debug logging:
> 
> DRM is biggest use-case: 23 macros, issuing 10 exclusive categories of
> messages, from ~5100 callsites, across core (drm, _*helpers), and 3+
> drivers (Im working amdgpu, i915, more recently nouveau).  These mostly
> flow to drm_debug_enabled(category) for a print/no decision.
> 
> nouveau has minimum direct use of the DRM.debug macros, but does use
> pr_debug (in VMM iirc), and drm_debug_enabled() in ~50 places via
> macros, and another ~50 iirc due to NOUVEAU_DEBUG_MMU=y
> 
> What nouveau has most of is log-levels: there are ~800 uses of them;
> nvkm_(fatal|error|warn|info|debug|trace|spam), they all flow thru
> nvkm_printk_.  Even excluding some levels as "always-on" and not
> appropriate for dyndbg's extra resources and complexity, theres ~450
> callsites.
> 
> A reported smattering of raw/adhoc debug code. all but unknown to me.
> 
> Like any debug logging, they're mostly off, and should have close to
> 0-off-cost.  This is what dyndbg (with/on jump-label) was made for.
> 
> Bottom line: in order to unify more potential (drm,etc) use-cases,
> dyndbg needs to support both debug classification schemes:
> RELATED/LEVEL_NUM and INDEPENDENT/DISJOINT_BITS.
> 
> This is rev3. rev2 is here:
> https://lore.kernel.org/lkml/20220516225640.3102269-1-jim.cromie@gmail.com/
> 
> summary of diffs:
> 
>  - rebased on 5.19-rc6 to pick up kernel/module changes
>  - tracfs bits now use __vstring, __vstr_assign, from S.Rostedt
>  
>  - 4 class-map-types - as outlined above
>    now supports LEVEL_NUM semantics, WIP nouveau integration.
>    v2 became the DISJOINT_BITS use case
>    Lots of API-ish surface area here *RFC*
> 
>  - class-maps now in section("__dyndbg_classes")
>    class FOO queries are available at earlyboot / module-load
>    drop (un)?register_classes()
> 
>  - test-dynamic-debug module
>    tests the 4 CLASS-TYPES
>    good place to bikeshed / paintshop the API
> 
>  - nouveau - start poking - WIP
>    NV_PRINT -> dev_dbg (creates 632 prdbgs, but not class'd)
>    LEVEL_NUM classes declared to see how they "fit", unused yet.
> 
> Summary:
> 
>  - plenty of new stuff here.
>  - plenty of new API surface area.
>  - exposes CLASSNAMES to user, via control, >symbolic-sysknob
> 
> More on LEVEL_NUM:
> 
> dyndbg's class scheme is names-based, so even for LEVEL_NUM with
> numeric input, there must be a "V0" name; a name with which to turn
> off "V1".  And don't do 'pr_dbg_class(0,..)'.
> 
> LEVEL_NUM is an overlay on DISJOINT_BITS; the callback reads the input as a
> level, and computes and applies the bitmap to enforce it.  Yes it
> wastes "V0" bit.  That might matter if an author wanted many separate
> verbose-knobs with a few levels each, but that seems fairly unlikely.
> 
> More importantly, it means that relative verbosity is not enforced at
> the >control input; IOW this is allowed:
> 
>    :#> echo class V1 -p > /proc/dynamic_debug/control
>    :#> echo class V3 +p > /proc/dynamic_debug/control
> 
> 2nd line doesn't undo 1st, as it would if changed via sysfs-knob:
> 
>    :#> echo 3 > /sys/module/drm/parameters/debug
> 
> ISTM this is fine, the "relative" meaning is added at the interface,
> where it presents to a user.  Doing otherwise means surgery to
> ddebug_change, which seems unnecessary given an option.
> 
> CLASS NAMESPACE and DRM
> 
> The class namespace is flat and wide, so "V1" is a poor choice, other
> than for demonstration (as in test_dynamic_debug module).  If every
> module had a "V1", turning them all on would issue lots of unrelated
> noise.
> 
> Instead, class DRM_UT_CORE has a name with a specific sub-system wide
> (ie multi-module) meaning, and can (and should) be responded to by all
> cooperating modules.
> 
> For DRM, this means 4-5 duplicate uses of DEFINE_DYNDBG_CLASSMAP, from
> multiple drivers' "*_{drm,dev,main}.c" files; all of them agreeing on
> the classnames, map-type and base.  Though repetitive, and a bit
> fiddly when multiple classes share the module's id-space, it is
> simple, and consistent with the "static struct foo = {INIT_expr}"
> pattern used in the macro.  Im open to simpler ways, initializing an
> extern sounded like a maze w/o cheese.
> 
> For core, drm_print.c has an additional task; it defines and
> initializes the bitmap sysknob that converts bits to a query:
> 
>   static struct ddebug_classes_bitmap_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);
> 
> then the callback converts bit-toggles on input into something like:
> 
>   :#> echo class DRM_UT_KMS +p > control
> 
> which enables all drm_dbg_kms() callsites in all modules that declared
> that classname as known.
> 
> NB: classmaps and classes_bitmap_params are different structs.  this
> allows the former to be shared by 2 of latter, each toggling 'p' & 'T'
> flags, to control output to syslog or tracelog independently.
> 
> NBB: while "V1" isnt a good classname, "EMERG" and and other
> KERN-LEVEL names have a legacy.  That said, dyndbg shouldnt be
> involved in EMERG actions.
> 
> NOUVEAU and multiple LEVEL_NUM knobs ?
> 
> One thing nouveau has that I havent yet grokked is 2|3 independent
> verbose levels, in {,cli,sub}->debug (see subdev.h).  But Ive coded
> them as 2 more macro invocations; using bases 10, 15 to avoid/respect
> the 0-9 mapping of DRM.debug categories to those class-ids.
> 
> With this, the drm subsystem uses 20/31 of its class-id range, perhaps
> 63 is better, despite the cumbersome 0x-64bit interface.  Note that
> the sysfs-knobs do not expose the base/offset (its an inward-facing
> .class_id offset); each sysfs-knob gets its own 0..N bitmap, the base
> maps it to the 0..30 subrange allocated (manually, via the base arg to
> macro) for this class-map.
> 
> anyway, heres how `modprobe nouveau` goes with dynamic_debug.verbose=3
> 
> [86512.693954] dyndbg: class[0]: module:nouveau base:15 len:5 ty:1
> [86512.693958] dyndbg:  15: 0 NV_SUBDEV_DBG_OFF		# aka V0
> [86512.693959] dyndbg:  16: 1 NV_SUBDEV_DBG_INFO
> [86512.693960] dyndbg:  17: 2 NV_SUBDEV_DBG_DEBUG
> [86512.693960] dyndbg:  18: 3 NV_SUBDEV_DBG_TRACE
> [86512.693960] dyndbg:  19: 4 NV_SUBDEV_DBG_SPAM
> [86512.693961] dyndbg: class[1]: module:nouveau base:10 len:5 ty:1
> [86512.693961] dyndbg:  10: 0 NV_CLI_DBG_OFF
> [86512.693962] dyndbg:  11: 1 NV_CLI_DBG_INFO
> [86512.693962] dyndbg:  12: 2 NV_CLI_DBG_DEBUG
> [86512.693963] dyndbg:  13: 3 NV_CLI_DBG_TRACE
> [86512.693963] dyndbg:  14: 4 NV_CLI_DBG_SPAM
> [86512.693963] dyndbg: class[2]: module:nouveau base:0 len:10 ty:0
> [86512.693964] dyndbg:  0: 0 DRM_UT_CORE
> [86512.693964] dyndbg:  1: 1 DRM_UT_DRIVER
> [86512.693965] dyndbg:  2: 2 DRM_UT_KMS
> [86512.693965] dyndbg:  3: 3 DRM_UT_PRIME
> [86512.693965] dyndbg:  4: 4 DRM_UT_ATOMIC
> [86512.693966] dyndbg:  5: 5 DRM_UT_VBL
> [86512.693966] dyndbg:  6: 6 DRM_UT_STATE
> [86512.693966] dyndbg:  7: 7 DRM_UT_LEASE
> [86512.693967] dyndbg:  8: 8 DRM_UT_DP
> [86512.693967] dyndbg:  9: 9 DRM_UT_DRMRES
> [86512.693968] dyndbg: module:nouveau attached 3 classes
> [86512.693968] dyndbg: 632 debug prints in module nouveau
> 
> They are not yet wired by class; the nv-printks are using dev_dbg for
> now, so they can be enabled with standard selections (module, func,
> etc).
> 
> DYNDBG API
> 
> I added __pr_debug_cls to make things testable, I wanted to keep it
> private/un-api, because drm already has drm_dbg_<cat>(cat, fmt..), and
> that seemed a pretty good model to follow: enums with strong names for
> class_id constants, and same names for classes.
> 
>    ie: __pr_debug_cls(DRM_UT_KMS, "Whats the Matter with KMS: %s\n", reason);
> 
> But now nouveau probably wants/needs it, perhaps others too.
> 
>   pr_dbg_cls / dev_dbg_cls ?  class or debug spelled out ? 
> 
> MORE TESTING with DRM & TRACEFS
> 
> Most dev & testing has been on virtme, with test-dynamic-debug module
> doing an api-validation-demonstration.  The test module proves
> multiple sysknobs, but cannot prove real multi-module sharing of the
> class-name space.  The DRM.debug adaptation must (and does) do that.
> 
> Now Im running on real gpu/drm hw; on both an amdgpu desktop, and this
> amdgpu+nouveau laptop.  Its stable enough to type on, browse, build
> more kernels, etc.
> 
> :#> uname -r
> 5.18.0-f2-00038-g61d300083196
> :#> wc /proc/dynamic_debug/control 
> 11554 95556 1442827 /proc/dynamic_debug/control
> :#> lsmod | grep drm
> drm_buddy              20480  1 i915
> drm_ttm_helper         16384  2 amdgpu,nouveau
> ttm                    86016  4 amdgpu,drm_ttm_helper,i915,nouveau
> drm_dp_helper         184320  3 amdgpu,i915,nouveau
> drm_kms_helper        208896  6 drm_dp_helper,amdgpu,i915,nouveau
> drm                   655360  16 gpu_sched,drm_dp_helper,drm_kms_helper,drm_buddy,amdgpu,drm_ttm_helper,i915,ttm,nouveau
> cec                    49152  2 drm_dp_helper,i915
> 
> I've never turned on DRM.debug in frustration (or curiousity until
> recently); I dunno what normal traffic looks like.  So I wrote a
> script to toggle each category: on/off for 1 sec, so I could 'more'
> thru the output to see the partitioned streams.
> 
> Different runs (of '10' sec of active tracing) produce between 330-3500
> lines of logging, depending upon mousing/screen activity.  Heres a bit
> of a many-window-select run: `wc trace` gives "size" of the category's stream.
> 
> :#> trc_classes 
> 12 /sys/kernel/tracing/trace
> doing class DRM_UT_CORE +/- T   1394 13941 141614 /sys/kernel/tracing/trace
> doing class DRM_UT_DRIVER +/- T   1396 13959 141816 /sys/kernel/tracing/trace
> doing class DRM_UT_KMS +/- T   1482 14521 148246 /sys/kernel/tracing/trace
> doing class DRM_UT_PRIME +/- T   1484 14539 148446 /sys/kernel/tracing/trace
> doing class DRM_UT_ATOMIC +/- T   2984 31658 396064 /sys/kernel/tracing/trace
> doing class DRM_UT_VBL +/- T   3411 37321 449848 /sys/kernel/tracing/trace
> doing class DRM_UT_STATE +/- T   3413 37339 450048 /sys/kernel/tracing/trace
> doing class DRM_UT_LEASE +/- T   3415 37357 450248 /sys/kernel/tracing/trace
> doing class DRM_UT_DP +/- T   3417 37375 450442 /sys/kernel/tracing/trace
> doing class DRM_UT_DRMRES +/- T   3419 37393 450644 /sys/kernel/tracing/trace
> 
> and some mid-run output from a quiet run, with less repetition.
> 
>             bash-96790   [006] ..... 410237.432255: tracing_mark_write: doing class DRM_UT_DRIVER +T
>             bash-96790   [006] ..... 410238.610319: tracing_mark_write: doing class DRM_UT_DRIVER -T
>             bash-96790   [006] ..... 410239.776285: tracing_mark_write: doing class DRM_UT_KMS +T
>      gnome-shell-2101    [003] ..... 410239.923029: drm_debug: [FB:98]
>   kworker/u32:10-367584  [010] ..... 410239.924627: drm_debug: Allow idle optimizations (MALL): 0
>    kworker/u32:0-364714  [008] ..... 410239.935126: drm_debug: Allow idle optimizations (MALL): 1
>      gnome-shell-2101    [003] ..... 410240.527186: drm_debug: [FB:100]
>    kworker/u32:0-364714  [008] ..... 410240.528686: drm_debug: Allow idle optimizations (MALL): 0
>   kworker/u32:10-367584  [010] ..... 410240.539378: drm_debug: Allow idle optimizations (MALL): 1
>             bash-96790   [006] ..... 410240.957921: tracing_mark_write: doing class DRM_UT_KMS -T
>             bash-96790   [006] ..... 410242.199120: tracing_mark_write: doing class DRM_UT_PRIME +T
>             bash-96790   [006] ..... 410243.301988: tracing_mark_write: doing class DRM_UT_PRIME -T
>             bash-96790   [006] ..... 410244.416400: tracing_mark_write: doing class DRM_UT_ATOMIC +T
>      gnome-shell-2101    [003] ..... 410244.653372: drm_devdbg: cat:4, (0xffff8f26c173de00:0000:06:00.0)[UNSAFE-MEMORY] Allocated atomic state 000000001f1e6cb6
>      gnome-shell-2101    [003] ..... 410244.653381: drm_devdbg: cat:4, (0xffff8f26c173de00:0000:06:00.0)[UNSAFE-MEMORY] Added [PLANE:55:plane-3] 00000000785ae904 state to 000000001f1e6cb6
>      gnome-shell-2101    [003] ..... 410244.653384: drm_devdbg: cat:4, (0xffff8f26c173de00:0000:06:00.0)[UNSAFE-MEMORY] Added [CRTC:67:crtc-0] 00000000b06ca618 state to 000000001f1e6cb6
>      gnome-shell-2101    [003] ..... 410244.653389: drm_devdbg: cat:4, (0xffff8f26c173de00:0000:06:00.0)[UNSAFE-MEMORY] Set [FB:98] for [PLANE:55:plane-3] state 00000000785ae904
>      gnome-shell-2101    [003] ..... 410244.653392: drm_devdbg: cat:4, (0xffff8f26c173de00:0000:06:00.0)[UNSAFE-MEMORY] checking 000000001f1e6cb6
>      gnome-shell-2101    [003] ..... 410244.653407: drm_devdbg: cat:4, (0xffff8f26c173de00:0000:06:00.0)[UNSAFE-MEMORY] committing 000000001f1e6cb6 nonblocking
>    kworker/u32:0-364714  [010] ..... 410244.653729: drm_debug: amdgpu_crtc id:0 crtc_state_flags: enable:1, active:1, planes_changed:1, mode_changed:0,active_changed:0,connectors_changed:0
>    kworker/u32:0-364714  [010] ..... 410244.654642: drm_debug: plane: id=3 dcc_en=0
> 
> a few things to note in the trace output:
> 
> . the event-name: drm_(debug|devdbg) is not very informative
> 
> . drm_devdbg fmt has cat:%d, it could be the classname, but that should
>   replace event-name, not supplement it. this pertains to drm_debug too.
> 
> . drm_devdbg has lots of (dev-info), that could be optional on a new flag(s)
> 
> 
> If anyone wants to repeat the above with the patchset, the .rc file follows:
> 
> events_3() {
>     local a=$1
>     local b=$2
>     local c=$3
>     echo $a > /sys/kernel/tracing/events/dyndbg/enable
>     # avoid drm_vblank*, its noisy
>     echo $b > /sys/kernel/tracing/events/drm/drm_debug/enable
>     echo $c > /sys/kernel/tracing/events/drm/drm_devdbg/enable
> }
> 
> flags_class() {
>     local flgs=$1;
>     local cls=$2;
>     echo class $cls $flgs > /proc/dynamic_debug/control
> }
> 
> # turn on each DRM_UT_* for 1 second each.
> # kinda shows relative traffic of each category
> # separated into blocks to get flavor of each
> 
> drm_classes() {
>     local flgs=$1
>     [ -z $flgs ] && flgs="p"
> 
>     #echo > /sys/kernel/tracing/trace
>     #wc /sys/kernel/tracing/trace
> 
>     for cls in 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;
>     do
> 	echo -n doing class $cls "  "
> 
> 	echo doing class $cls +$flgs
> 	sleep .1
> 	flags_class +$flgs $cls
> 	sleep 1
> 	
> 	echo doing class $cls -$flgs
> 	sleep .1
> 	flags_class -$flgs $cls
> 	sleep 1
> 	
> 	#wc /sys/kernel/tracing/trace
>     done
> }
> 
> # like above but with T flag, and markers, trace/enable
> trc_classes() {
>     local flgs=$1
>     [ -z $flgs ] && flgs="T"
> 
>     echo > /sys/kernel/tracing/trace
>     wc -l /sys/kernel/tracing/trace
> 
>     events_3 1 1 1
>     for cls in 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;
>     do
> 	echo -n doing class $cls +/- $flgs "  "
> 
> 	echo doing class $cls +$flgs > /sys/kernel/tracing/trace_marker
> 	sleep .1
> 	flags_class +$flgs $cls
> 	sleep 1
> 	
> 	echo doing class $cls -$flgs > /sys/kernel/tracing/trace_marker
> 	sleep .1
> 	flags_class -$flgs $cls
> 	sleep 1
> 	
> 	wc /sys/kernel/tracing/trace
> 
>     done
>     events_3 0 0 0
> }
> 
> 
> Jim Cromie (33):
> 
> 1st, a group of "cleanups"
> 
>   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 local vars in ddebug_init
>   dyndbg: create and use struct _ddebug_info
> 
> class FOO support  
> 
>   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
> 
> add dyndbg-class-param support
> 
>   dyndbg: add drm.debug style (drm/parameters/debug) bitmap support
>   dyndbg: test DECLARE_DYNDBG_CLASSMAP, sysfs nodes
> 
> drm.debug adaptation
> 
>   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-LEVEL_NUM integration: WIP/exploratory.
> 
>   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
> 
>  .../admin-guide/dynamic-debug-howto.rst       | 246 +++++-----
>  MAINTAINERS                                   |   2 +
>  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                   |  48 +-
>  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/vmlinux.lds.h             |   3 +
>  include/drm/drm_print.h                       |  85 +++-
>  include/linux/dynamic_debug.h                 | 176 +++++--
>  kernel/module/internal.h                      |   4 +-
>  kernel/module/main.c                          |  20 +-
>  lib/Kconfig.debug                             |  10 +
>  lib/Makefile                                  |   1 +
>  lib/dynamic_debug.c                           | 450 +++++++++++++++---
>  lib/test_dynamic_debug.c                      | 165 +++++++
>  23 files changed, 1099 insertions(+), 269 deletions(-)
>  create mode 100644 lib/test_dynamic_debug.c
> 
> -- 
> 2.37.1
> 

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