[PATCH 0/4] dyndbg: POC use dynamic_debug_exec_queries in DRM

[PATCH 0/4] dyndbg: POC use dynamic_debug_exec_queries in DRM

[Jim Cromie]

This patchset tests/demonstrates using dynamic_debug_exec_queries() to
alter 2 drivers' pr_debugs without a user directly using >control.

For drm.core, I copied drm.debug module parameter model, adding
drm.debug2 as a POC user interface to control 2 pr_debug additions to
drm_printk:drm_dbg,dev_dbg, allowing both category and >control to
work in parallel.  This patch makes no attempt to integrate drm's
category mechanism with the "format=^class" callsite selection; thats
the "theory", but it needs testing.

For i915/gvt, I repeated the pattern.  I focussed on gvt only, because
it had the most compelling use of format strings as pr_debug classes;
~120 pr_debugs in 9 classes.  These are mapped onto bits of the param.

bash-5.0# echo 0x0 > /sys/module/i915/parameters/debug_dyn 
[ 3137.044185] set_dyndbg: result:0x0 from 0x0
[ 3137.044185] 
[ 3137.047370] dyndbg: query 0: "format='^gvt: cmd: ' -p"
[ 3137.050302] dyndbg: entry, buf:'format='^gvt: cmd: ' -p'
[ 3137.053331] dyndbg: start-of-word:0 'format='^gvt: cmd: ' -p'

These patches were the test/use case for-59 fixes:
https://lore.kernel.org/lkml/20200825173339.2082585-1-jim.cromie@gmail.com/


Jim Cromie (4):
  drm-printk: POC caller of dynamic-debug-exec-queries
  drm-printk: call pr_debug() from drm_dev_dbg, __drm_dbg
  i915: add -DDYNAMIC_DEBUG_MODULE to i915/gvt/Makefile
  i915: POC use dynamic_debug_exec_queries to control pr_debugs in gvt

 drivers/gpu/drm/drm_print.c        | 54 ++++++++++++++++++---
 drivers/gpu/drm/i915/gvt/Makefile  |  5 +-
 drivers/gpu/drm/i915/i915_params.c | 76 ++++++++++++++++++++++++++++++
 3 files changed, 127 insertions(+), 8 deletions(-)

-- 
2.26.2

[PATCH 1/4] drm-printk: POC caller of dynamic-debug-exec-queries

[Jim Cromie]

Export of dynamic-debug-exec-queries exists for users like drm.

This commit is a 1st user-test; it adds a 2nd knob, __drm_debug2,
similar in function to __drm_debug.  module_param_cb wires it to a
callback which maps the input value to one of: "module=drm* +/-p".

The include is needed to see the exported function prototype.

Notes:

The define DEBUG at top of drm-printk enables all pr_debug()s,
independent of CONFIG_DYNAMIC_DEBUG_CORE.

drm-printk is an independent print control system using __drm_debug
bits.  The plan is to find the low-level macros in which to insert a
pr_debug call, their eventual callsites will have distinct METADATA,
so will be itemized in control, and individually selectable.

Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
---
 drivers/gpu/drm/drm_print.c | 35 +++++++++++++++++++++++++++++++++++
 1 file changed, 35 insertions(+)

diff --git a/drivers/gpu/drm/drm_print.c b/drivers/gpu/drm/drm_print.c
index 111b932cf2a9..52abaf2ae053 100644
--- a/drivers/gpu/drm/drm_print.c
+++ b/drivers/gpu/drm/drm_print.c
@@ -27,6 +27,7 @@
 
 #include <stdarg.h>
 
+#include <linux/dynamic_debug.h>
 #include <linux/io.h>
 #include <linux/moduleparam.h>
 #include <linux/seq_file.h>
@@ -54,6 +55,40 @@ MODULE_PARM_DESC(debug, "Enable debug output, where each bit enables a debug cat
 "\t\tBit 8 (0x100) will enable DP messages (displayport code)");
 module_param_named(debug, __drm_debug, int, 0600);
 
+/* POC for callback -> ddebug_exec_queries */
+unsigned int __drm_debug2;
+EXPORT_SYMBOL(__drm_debug2);
+
+static int param_set_dyndbg(const char *val, const struct kernel_param *kp)
+{
+	int chgct, result;
+
+	result = kstrtouint(val, 0, (unsigned int *)kp->arg);
+	pr_warn("set_dyndbg: result:%d from %s\n", result, val);
+
+	if (result)
+		chgct = dynamic_debug_exec_queries("module=drm* +p", NULL);
+	else
+		chgct = dynamic_debug_exec_queries("module=drm* -p", NULL);
+
+	pr_warn("change ct:%d\n", chgct);
+	return 0;
+}
+static int param_get_dyndbg(char *buffer, const struct kernel_param *kp)
+{
+	return scnprintf(buffer, PAGE_SIZE, "%u\n",
+			 *((unsigned int *)kp->arg));
+}
+static const struct kernel_param_ops param_ops_dyndbg = {
+	.set = param_set_dyndbg,
+	.get = param_get_dyndbg,
+};
+
+MODULE_PARM_DESC(debug_dyn, "Enable debug output, where each bit enables a debug category.\n"
+		 "\t\tthese wont work yet\n");
+module_param_cb(debug_dyn, &param_ops_dyndbg, &__drm_debug2, 0644);
+
+
 void __drm_puts_coredump(struct drm_printer *p, const char *str)
 {
 	struct drm_print_iterator *iterator = p->arg;
-- 
2.26.2

Re: [PATCH 1/4] drm-printk: POC caller of dynamic-debug-exec-queries

[kernel test robot]

[-- Attachment #1: Type: text/plain, Size: 4919 bytes --]

Hi Jim,

I love your patch! Yet something to improve:

[auto build test ERROR on drm-intel/for-linux-next]
[also build test ERROR on linux/master tegra-drm/drm/tegra/for-next drm-tip/drm-tip linus/master v5.9-rc2 next-20200826]
[cannot apply to drm/drm-next]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch]

url:    https://github.com/0day-ci/linux/commits/Jim-Cromie/dyndbg-POC-use-dynamic_debug_exec_queries-in-DRM/20200827-010409
base:   git://anongit.freedesktop.org/drm-intel for-linux-next
config: microblaze-randconfig-r006-20200826 (attached as .config)
compiler: microblaze-linux-gcc (GCC) 9.3.0
reproduce (this is a W=1 build):
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # save the attached .config to linux build tree
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-9.3.0 make.cross ARCH=microblaze 

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>

All errors (new ones prefixed by >>):

   In file included from drivers/gpu/drm/drm_print.c:30:
   include/linux/dynamic_debug.h: In function 'ddebug_dyndbg_module_param_cb':
>> include/linux/dynamic_debug.h:196:3: error: implicit declaration of function 'printk'; did you mean 'bprintf'? [-Werror=implicit-function-declaration]
     196 |   printk(KERN_WARNING "dyndbg param is supported only in "
         |   ^~~~~~
         |   bprintf
>> include/linux/dynamic_debug.h:196:10: error: 'KERN_WARNING' undeclared (first use in this function)
     196 |   printk(KERN_WARNING "dyndbg param is supported only in "
         |          ^~~~~~~~~~~~
   include/linux/dynamic_debug.h:196:10: note: each undeclared identifier is reported only once for each function it appears in
>> include/linux/dynamic_debug.h:196:22: error: expected ')' before string constant
     196 |   printk(KERN_WARNING "dyndbg param is supported only in "
         |                      ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
         |                      )
   In file included from include/linux/kernel.h:15,
                    from include/asm-generic/bug.h:19,
                    from ./arch/microblaze/include/generated/asm/bug.h:1,
                    from include/linux/bug.h:5,
                    from include/linux/io.h:11,
                    from drivers/gpu/drm/drm_print.c:31:
   include/linux/printk.h: At top level:
>> include/linux/printk.h:171:5: error: conflicting types for 'printk'
     171 | int printk(const char *fmt, ...);
         |     ^~~~~~
   include/linux/printk.h:171:1: note: a parameter list with an ellipsis can't match an empty parameter name list declaration
     171 | int printk(const char *fmt, ...);
         | ^~~
   In file included from drivers/gpu/drm/drm_print.c:30:
   include/linux/dynamic_debug.h:196:3: note: previous implicit declaration of 'printk' was here
     196 |   printk(KERN_WARNING "dyndbg param is supported only in "
         |   ^~~~~~
   drivers/gpu/drm/drm_print.c: In function 'param_set_dyndbg':
>> drivers/gpu/drm/drm_print.c:70:11: error: implicit declaration of function 'dynamic_debug_exec_queries' [-Werror=implicit-function-declaration]
      70 |   chgct = dynamic_debug_exec_queries("module=drm* +p", NULL);
         |           ^~~~~~~~~~~~~~~~~~~~~~~~~~
   cc1: some warnings being treated as errors

# https://github.com/0day-ci/linux/commit/ad959a93dccb8fe5deb5a7da3e22049779571b9b
git remote add linux-review https://github.com/0day-ci/linux
git fetch --no-tags linux-review Jim-Cromie/dyndbg-POC-use-dynamic_debug_exec_queries-in-DRM/20200827-010409
git checkout ad959a93dccb8fe5deb5a7da3e22049779571b9b
vim +196 include/linux/dynamic_debug.h

e9d376f0fa66bd6 Jason Baron 2009-02-05  190  
b48420c1d3019ce Jim Cromie  2012-04-27  191  static inline int ddebug_dyndbg_module_param_cb(char *param, char *val,
b48420c1d3019ce Jim Cromie  2012-04-27  192  						const char *modname)
b48420c1d3019ce Jim Cromie  2012-04-27  193  {
b48420c1d3019ce Jim Cromie  2012-04-27  194  	if (strstr(param, "dyndbg")) {
516cf1be07cf3ab Jim Cromie  2012-05-01  195  		/* avoid pr_warn(), which wants pr_fmt() fully defined */
516cf1be07cf3ab Jim Cromie  2012-05-01 @196  		printk(KERN_WARNING "dyndbg param is supported only in "
b48420c1d3019ce Jim Cromie  2012-04-27  197  			"CONFIG_DYNAMIC_DEBUG builds\n");
b48420c1d3019ce Jim Cromie  2012-04-27  198  		return 0; /* allow and ignore */
b48420c1d3019ce Jim Cromie  2012-04-27  199  	}
b48420c1d3019ce Jim Cromie  2012-04-27  200  	return -EINVAL;
b48420c1d3019ce Jim Cromie  2012-04-27  201  }
b48420c1d3019ce Jim Cromie  2012-04-27  202  

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org

[-- Attachment #2: .config.gz --]
[-- Type: application/gzip, Size: 29002 bytes --]

Re: [PATCH 1/4] drm-printk: POC caller of dynamic-debug-exec-queries

[kernel test robot]

[-- Attachment #1: Type: text/plain, Size: 4130 bytes --]

Hi Jim,

I love your patch! Yet something to improve:

[auto build test ERROR on drm-intel/for-linux-next]
[also build test ERROR on linux/master drm-tip/drm-tip linus/master v5.9-rc2 next-20200826]
[cannot apply to drm/drm-next]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch]

url:    https://github.com/0day-ci/linux/commits/Jim-Cromie/dyndbg-POC-use-dynamic_debug_exec_queries-in-DRM/20200827-010409
base:   git://anongit.freedesktop.org/drm-intel for-linux-next
config: arm64-randconfig-r002-20200826 (attached as .config)
compiler: clang version 12.0.0 (https://github.com/llvm/llvm-project 7cfcecece0e0430937cf529ce74d3a071a4dedc6)
reproduce (this is a W=1 build):
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # install arm64 cross compiling tool for clang build
        # apt-get install binutils-aarch64-linux-gnu
        # save the attached .config to linux build tree
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross ARCH=arm64 

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>

All errors (new ones prefixed by >>):

   In file included from drivers/gpu/drm/drm_print.c:30:
>> include/linux/dynamic_debug.h:196:3: error: implicit declaration of function 'printk' [-Werror,-Wimplicit-function-declaration]
                   printk(KERN_WARNING "dyndbg param is supported only in "
                   ^
>> include/linux/dynamic_debug.h:196:10: error: use of undeclared identifier 'KERN_WARNING'
                   printk(KERN_WARNING "dyndbg param is supported only in "
                          ^
   In file included from drivers/gpu/drm/drm_print.c:31:
   In file included from include/linux/io.h:11:
   In file included from include/linux/bug.h:5:
   In file included from arch/arm64/include/asm/bug.h:26:
   In file included from include/asm-generic/bug.h:19:
   In file included from include/linux/kernel.h:15:
   include/linux/printk.h:171:5: error: conflicting types for 'printk'
   int printk(const char *fmt, ...);
       ^
   include/linux/dynamic_debug.h:196:3: note: previous implicit declaration is here
                   printk(KERN_WARNING "dyndbg param is supported only in "
                   ^
>> drivers/gpu/drm/drm_print.c:70:11: error: implicit declaration of function 'dynamic_debug_exec_queries' [-Werror,-Wimplicit-function-declaration]
                   chgct = dynamic_debug_exec_queries("module=drm* +p", NULL);
                           ^
   4 errors generated.

# https://github.com/0day-ci/linux/commit/ad959a93dccb8fe5deb5a7da3e22049779571b9b
git remote add linux-review https://github.com/0day-ci/linux
git fetch --no-tags linux-review Jim-Cromie/dyndbg-POC-use-dynamic_debug_exec_queries-in-DRM/20200827-010409
git checkout ad959a93dccb8fe5deb5a7da3e22049779571b9b
vim +/printk +196 include/linux/dynamic_debug.h

e9d376f0fa66bd6 Jason Baron 2009-02-05  190  
b48420c1d3019ce Jim Cromie  2012-04-27  191  static inline int ddebug_dyndbg_module_param_cb(char *param, char *val,
b48420c1d3019ce Jim Cromie  2012-04-27  192  						const char *modname)
b48420c1d3019ce Jim Cromie  2012-04-27  193  {
b48420c1d3019ce Jim Cromie  2012-04-27  194  	if (strstr(param, "dyndbg")) {
516cf1be07cf3ab Jim Cromie  2012-05-01  195  		/* avoid pr_warn(), which wants pr_fmt() fully defined */
516cf1be07cf3ab Jim Cromie  2012-05-01 @196  		printk(KERN_WARNING "dyndbg param is supported only in "
b48420c1d3019ce Jim Cromie  2012-04-27  197  			"CONFIG_DYNAMIC_DEBUG builds\n");
b48420c1d3019ce Jim Cromie  2012-04-27  198  		return 0; /* allow and ignore */
b48420c1d3019ce Jim Cromie  2012-04-27  199  	}
b48420c1d3019ce Jim Cromie  2012-04-27  200  	return -EINVAL;
b48420c1d3019ce Jim Cromie  2012-04-27  201  }
b48420c1d3019ce Jim Cromie  2012-04-27  202  

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org

[-- Attachment #2: .config.gz --]
[-- Type: application/gzip, Size: 41381 bytes --]

[PATCH 2/4] drm-printk: call pr_debug() from drm_dev_dbg, __drm_dbg

[Jim Cromie]

Put the pr_debug() after the vaf setup work, so as to use it.  And
move the if-category-disabled-return after both, so the pr_debug()
runs unconditionally.

This lets both debug-printers execute independently, according to
their respective controls, allowing later comparison to each other.

 #> echo module=drm +pmftl > /proc/dynamic_debug/control
yields logging like:

 [1772] drm:drm_dev_dbg:305: i915 0000:00:02.0: [drm:intel_atomic_get_global_obj_state [i915]]
   Cat:16 Added new global object 000000006fa51dd6 state 00000000bbddcf9d to 000000005f6e1bc3
 [1772] drm:drm_dev_dbg:305: i915 0000:00:02.0: [drm:intel_atomic_get_global_obj_state [i915]]
   Cat:16 Added new global object 000000002a5e020a state 000000002b3685ed to 000000005f6e1bc3
 [198] drm:drm_dev_dbg:305: i915 0000:00:02.0: [drm:drm_update_vblank_count [drm]]
   Cat:32 updating vblank count on crtc 0: current=260920, diff=0, hw=192024 hw_last=192024
 [1772] drm:__drm_dbg:331: [drm:drm_atomic_nonblocking_commit [drm]] Cat:16 committing 000000005f6e1bc3 nonblocking
 [1772] drm:__drm_dbg:331: [drm:drm_mode_object_put.part.0 [drm]] Cat:1 OBJ ID: 113 (4)
 [1772] drm:__drm_dbg:331: [drm:drm_ioctl [drm]] Cat:1 comm="gnome-shell" pid=1772, dev=0xe200, auth=1, I915_GEM_CREATE
 [1772] drm:__drm_dbg:331: [drm:drm_ioctl [drm]] Cat:1 comm="gnome-shell" pid=1772, dev=0xe200, auth=1, I915_GEM_SET_DOMAIN
 [1772] drm:__drm_dbg:331: [drm:drm_ioctl [drm]] Cat:1 comm="gnome-shell" pid=1772, dev=0xe200, auth=1, I915_GEM_SET_TILING
 [1772] drm:__drm_dbg:331: [drm:drm_ioctl [drm]] Cat:1 comm="gnome-shell" pid=1772, dev=0xe200, auth=1, I915_GEM_MMAP_OFFSET

Clearly, the mflt flags arent very helpful here, and callsite control
is all or nothing (since theres only 2 callsites handling all the
categories).  We are 1 below the function layer of interest, but
theres room for optimism.

Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
---
 drivers/gpu/drm/drm_print.c | 27 +++++++++++++++++----------
 1 file changed, 17 insertions(+), 10 deletions(-)

diff --git a/drivers/gpu/drm/drm_print.c b/drivers/gpu/drm/drm_print.c
index 52abaf2ae053..fa2bcf4ec475 100644
--- a/drivers/gpu/drm/drm_print.c
+++ b/drivers/gpu/drm/drm_print.c
@@ -27,6 +27,7 @@
 
 #include <stdarg.h>
 
+#define DYNAMIC_DEBUG_MODULE
 #include <linux/dynamic_debug.h>
 #include <linux/io.h>
 #include <linux/moduleparam.h>
@@ -61,17 +62,17 @@ EXPORT_SYMBOL(__drm_debug2);
 
 static int param_set_dyndbg(const char *val, const struct kernel_param *kp)
 {
-	int chgct, result;
+	int chgct, rc, result;
 
-	result = kstrtouint(val, 0, (unsigned int *)kp->arg);
-	pr_warn("set_dyndbg: result:%d from %s\n", result, val);
+	rc = kstrtouint(val, 0, &result);
+	pr_debug("set_dyndbg: rc:%d got:%d from %s\n", rc, result, val);
 
 	if (result)
 		chgct = dynamic_debug_exec_queries("module=drm* +p", NULL);
 	else
 		chgct = dynamic_debug_exec_queries("module=drm* -p", NULL);
 
-	pr_warn("change ct:%d\n", chgct);
+	pr_debug("change ct:%d\n", chgct);
 	return 0;
 }
 static int param_get_dyndbg(char *buffer, const struct kernel_param *kp)
@@ -297,13 +298,16 @@ 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))
-		return;
-
 	va_start(args, format);
 	vaf.fmt = format;
 	vaf.va = &args;
 
+	dev_dbg(dev, "[" DRM_NAME ":%ps] Cat:%d %pV",
+		__builtin_return_address(0), category, &vaf);
+
+	if (!drm_debug_enabled(category))
+		return;
+
 	if (dev)
 		dev_printk(KERN_DEBUG, dev, "[" DRM_NAME ":%ps] %pV",
 			   __builtin_return_address(0), &vaf);
@@ -320,13 +324,16 @@ void __drm_dbg(enum drm_debug_category category, const char *format, ...)
 	struct va_format vaf;
 	va_list args;
 
-	if (!drm_debug_enabled(category))
-		return;
-
 	va_start(args, format);
 	vaf.fmt = format;
 	vaf.va = &args;
 
+	pr_debug("[" DRM_NAME ":%ps] Cat:%d %pV",
+		 __builtin_return_address(0), category, &vaf);
+
+	if (!drm_debug_enabled(category))
+		return;
+
 	printk(KERN_DEBUG "[" DRM_NAME ":%ps] %pV",
 	       __builtin_return_address(0), &vaf);
 
-- 
2.26.2

[PATCH 3/4] i915: add -DDYNAMIC_DEBUG_MODULE to i915/gvt/Makefile

[Jim Cromie]

This addition to cflags enables dyndbg in the gvt component of the
i915 module, on a CONFIG_DYNAMIC_DEBUG_CORE build.

So here are the message classifications that the gvt driver uses.

   cut -d= -f2 | cut -d\  -f2,3 | \
   perl -ne 'chomp $_ && $h{$_}++; END{print "$_\" \tseen $h{$_}\n" for sort keys %h}'

"gvt: cmd:" 	seen 11
"gvt: core:" 	seen 48
"gvt: dpy:" 	seen 4
"gvt: el:" 	seen 21
"gvt: irq:" 	seen 1
"gvt: mm:" 	seen 6
"gvt: mmio:" 	seen 9
"gvt: render:" 	seen 1
"gvt: sched:" 	seen 15

Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
---
 drivers/gpu/drm/i915/gvt/Makefile | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/i915/gvt/Makefile b/drivers/gpu/drm/i915/gvt/Makefile
index ea8324abc784..2c581e910688 100644
--- a/drivers/gpu/drm/i915/gvt/Makefile
+++ b/drivers/gpu/drm/i915/gvt/Makefile
@@ -5,5 +5,6 @@ GVT_SOURCE := gvt.o aperture_gm.o handlers.o vgpu.o trace_points.o firmware.o \
 	execlist.o scheduler.o sched_policy.o mmio_context.o cmd_parser.o debugfs.o \
 	fb_decoder.o dmabuf.o page_track.o
 
-ccflags-y				+= -I $(srctree)/$(src) -I $(srctree)/$(src)/$(GVT_DIR)/
-i915-y					+= $(addprefix $(GVT_DIR)/, $(GVT_SOURCE))
+ccflags-y	+= -I $(srctree)/$(src) -I $(srctree)/$(src)/$(GVT_DIR)/
+ccflags-y	+= -DDYNAMIC_DEBUG_MODULE
+i915-y		+= $(addprefix $(GVT_DIR)/, $(GVT_SOURCE))
-- 
2.26.2

[PATCH 4/4] i915: POC use dynamic_debug_exec_queries to control pr_debugs in gvt

[Jim Cromie]

The gvt component of this driver has ~120 pr_debugs, in 9 "classes".
Add a "knob", like drm.debug, to map bits to these classes.

bash-5.0# echo 0x01 > /sys/module/i915/parameters/debug_dyn
 set_dyndbg: result:0x1 from 0x01
 dyndbg: query 0: "format='^gvt: cmd: ' +p"
 dyndbg: entry, buf:'format='^gvt: cmd: ' +p'
 dyndbg: start-of-word:0 'format='^gvt: cmd: ' +p'
 dyndbg: start-of-word:1 ''^gvt: cmd: ' +p'
 dyndbg: start-of-word:2 '+p'
 dyndbg: split into words: "format" "^gvt: cmd: " "+p"
 dyndbg: op='+'
 dyndbg: flags=0x1
 dyndbg: *flagsp=0x1 *maskp=0xffffffff
 dyndbg: key:'format' arg:'^gvt: cmd: '
 dyndbg: parsed: func="" file="" module="i915" format="^gvt: cmd: " lineno=0-0
 dyndbg: changed drivers/gpu/drm/i915/gvt/cmd_parser.c:3081 [i915]init_cmd_table =p
 dyndbg: changed drivers/gpu/drm/i915/gvt/cmd_parser.c:1376 [i915]gen8_check_mi_display_flip =p
 dyndbg: changed drivers/gpu/drm/i915/gvt/cmd_parser.c:1373 [i915]gen8_check_mi_display_flip =p
 dyndbg: changed drivers/gpu/drm/i915/gvt/cmd_parser.c:745 [i915]parser_exec_state_dump =p
 dyndbg: changed drivers/gpu/drm/i915/gvt/cmd_parser.c:744 [i915]parser_exec_state_dump =p
 dyndbg: changed drivers/gpu/drm/i915/gvt/cmd_parser.c:742 [i915]parser_exec_state_dump =p
 dyndbg: changed drivers/gpu/drm/i915/gvt/cmd_parser.c:733 [i915]parser_exec_state_dump =p
 dyndbg: changed drivers/gpu/drm/i915/gvt/cmd_parser.c:729 [i915]parser_exec_state_dump =p
 dyndbg: changed drivers/gpu/drm/i915/gvt/cmd_parser.c:722 [i915]parser_exec_state_dump =p
 dyndbg: changed drivers/gpu/drm/i915/gvt/cmd_parser.c:716 [i915]parser_exec_state_dump =p
 dyndbg: changed drivers/gpu/drm/i915/gvt/cmd_parser.c:691 [i915]print_opcode =p
 dyndbg: applied: func="" file="" module="i915" format="^gvt: cmd: " lineno=0-0
 dyndbg: processed 1 queries, with 11 matches, 0 errs
 change ct:11 on format='gvt: cmd: '
 change ct:11

Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
---
 drivers/gpu/drm/i915/i915_params.c | 76 ++++++++++++++++++++++++++++++
 1 file changed, 76 insertions(+)

diff --git a/drivers/gpu/drm/i915/i915_params.c b/drivers/gpu/drm/i915/i915_params.c
index 8d8db9ff0a48..4e1f01ab4865 100644
--- a/drivers/gpu/drm/i915/i915_params.c
+++ b/drivers/gpu/drm/i915/i915_params.c
@@ -255,3 +255,79 @@ void i915_params_free(struct i915_params *params)
 	I915_PARAMS_FOR_EACH(FREE);
 #undef FREE
 }
+
+/* POC for callback -> dynamic_debug_exec_queries */
+unsigned long __new_knob;
+EXPORT_SYMBOL(__new_knob);
+
+static char *pr_debug_classes[] = {
+	"gvt: cmd: ",
+	"gvt: core: ",
+	"gvt: dpy: ",
+	"gvt: el: ",
+	"gvt: irq: ",
+	"gvt: mm: ",
+	"gvt: mmio: ",
+	"gvt: render: ",
+	"gvt: sched: "
+};
+#define NUM_CLASSES	ARRAY_SIZE(pr_debug_classes)
+#define OUR_QUERY_SIZE	128 /* we need about 20 */
+
+#include <linux/module.h>
+
+static int param_set_dyndbg(const char *instr, const struct kernel_param *kp)
+{
+	static unsigned long int old_val;
+        unsigned int val;
+	unsigned long int changes, result;
+	int rc, chgct = 0, totct = 0, bitpos;
+	char query[OUR_QUERY_SIZE];
+
+	rc = kstrtouint(instr, 0, &val);
+	if (rc) {
+		pr_err("set_dyndbg: failed\n");
+		return -EINVAL;
+	}
+	result = val;
+	pr_info("set_dyndbg: result:0x%lx from %s\n", result, instr);
+
+	changes = result ^ old_val;
+
+	for_each_set_bit(bitpos, &changes, NUM_CLASSES) {
+
+		sprintf(query, "format='^%s' %cp", pr_debug_classes[bitpos],
+			test_bit(bitpos, &result) ? '+' : '-');
+
+		chgct = dynamic_debug_exec_queries(query, "i915");
+		totct += chgct;
+		pr_info("change ct:%d on format='%s'\n", chgct,
+			pr_debug_classes[bitpos]);
+	}
+	old_val = result;
+	pr_info("change ct:%d\n", totct);
+	return 0;
+}
+static int param_get_dyndbg(char *buffer, const struct kernel_param *kp)
+{
+	return scnprintf(buffer, PAGE_SIZE, "%u\n",
+			 *((unsigned int *)kp->arg));
+}
+static const struct kernel_param_ops param_ops_dyndbg = {
+	.set = param_set_dyndbg,
+	.get = param_get_dyndbg,
+};
+
+MODULE_PARM_DESC(debug_dyn, " enable dynamic-debug by format-string classifications.\n"
+		 "\t\twhich are:"
+		 "\n\t\t gvt: cmd:"
+		 "\n\t\t gvt: core:"
+		 "\n\t\t gvt: dpy:"
+		 "\n\t\t gvt: el:"
+		 "\n\t\t gvt: irq:"
+		 "\n\t\t gvt: mm:"
+		 "\n\t\t gvt: mmio:"
+		 "\n\t\t gvt: render:"
+		 "\n\t\t gvt: sched:" "\n");
+
+module_param_cb(debug_dyn, &param_ops_dyndbg, &__new_knob, 0644);
-- 
2.26.2

Re: [PATCH 4/4] i915: POC use dynamic_debug_exec_queries to control pr_debugs in gvt

[kernel test robot]

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Hi Jim,

I love your patch! Yet something to improve:

[auto build test ERROR on drm-intel/for-linux-next]
[also build test ERROR on linux/master tegra-drm/drm/tegra/for-next drm-tip/drm-tip linus/master v5.9-rc2 next-20200826]
[cannot apply to drm/drm-next]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch]

url:    https://github.com/0day-ci/linux/commits/Jim-Cromie/dyndbg-POC-use-dynamic_debug_exec_queries-in-DRM/20200827-010409
base:   git://anongit.freedesktop.org/drm-intel for-linux-next
config: x86_64-allyesconfig (attached as .config)
compiler: gcc-9 (Debian 9.3.0-15) 9.3.0
reproduce (this is a W=1 build):
        # save the attached .config to linux build tree
        make W=1 ARCH=x86_64 

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>

All errors (new ones prefixed by >>):

   drivers/gpu/drm/i915/i915_params.c: In function 'param_set_dyndbg':
>> drivers/gpu/drm/i915/i915_params.c:307:11: error: implicit declaration of function 'dynamic_debug_exec_queries' [-Werror=implicit-function-declaration]
     307 |   chgct = dynamic_debug_exec_queries(query, "i915");
         |           ^~~~~~~~~~~~~~~~~~~~~~~~~~
   cc1: some warnings being treated as errors

# https://github.com/0day-ci/linux/commit/1b9bcd2cceed427d96bc9bf4eae6619201d645d6
git remote add linux-review https://github.com/0day-ci/linux
git fetch --no-tags linux-review Jim-Cromie/dyndbg-POC-use-dynamic_debug_exec_queries-in-DRM/20200827-010409
git checkout 1b9bcd2cceed427d96bc9bf4eae6619201d645d6
vim +/dynamic_debug_exec_queries +307 drivers/gpu/drm/i915/i915_params.c

   283	
   284	static int param_set_dyndbg(const char *instr, const struct kernel_param *kp)
   285	{
   286		static unsigned long int old_val;
   287	        unsigned int val;
   288		unsigned long int changes, result;
   289		int rc, chgct = 0, totct = 0, bitpos;
   290		char query[OUR_QUERY_SIZE];
   291	
   292		rc = kstrtouint(instr, 0, &val);
   293		if (rc) {
   294			pr_err("set_dyndbg: failed\n");
   295			return -EINVAL;
   296		}
   297		result = val;
   298		pr_info("set_dyndbg: result:0x%lx from %s\n", result, instr);
   299	
   300		changes = result ^ old_val;
   301	
   302		for_each_set_bit(bitpos, &changes, NUM_CLASSES) {
   303	
   304			sprintf(query, "format='^%s' %cp", pr_debug_classes[bitpos],
   305				test_bit(bitpos, &result) ? '+' : '-');
   306	
 > 307			chgct = dynamic_debug_exec_queries(query, "i915");
   308			totct += chgct;
   309			pr_info("change ct:%d on format='%s'\n", chgct,
   310				pr_debug_classes[bitpos]);
   311		}
   312		old_val = result;
   313		pr_info("change ct:%d\n", totct);
   314		return 0;
   315	}
   316	static int param_get_dyndbg(char *buffer, const struct kernel_param *kp)
   317	{
   318		return scnprintf(buffer, PAGE_SIZE, "%u\n",
   319				 *((unsigned int *)kp->arg));
   320	}
   321	static const struct kernel_param_ops param_ops_dyndbg = {
   322		.set = param_set_dyndbg,
   323		.get = param_get_dyndbg,
   324	};
   325	

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org

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