* [PATCH 01/13] dyndbg: fix static_branch manipulation
2022-02-17 3:48 [PATCH 00/12] use dynamic-debug under drm.debug api Jim Cromie
@ 2022-02-17 3:48 ` Jim Cromie
2022-02-17 3:48 ` [PATCH 02/13] dyndbg: add class_id field and query support Jim Cromie
` (11 subsequent siblings)
12 siblings, 0 replies; 15+ messages in thread
From: Jim Cromie @ 2022-02-17 3:48 UTC (permalink / raw)
To: jbaron, gregkh, linux-kernel, dri-devel, amd-gfx, intel-gvt-dev,
intel-gfx
Cc: daniel.vetter, seanpaul, robdclark, linux, joe, Jim Cromie,
vincent.whitchurch, stable
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,
did not use that result, but used 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 work
properly, 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
CC: stable@vger.kernel.org
Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
---
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",
--
2.35.1
^ permalink raw reply related [flat|nested] 15+ messages in thread* [PATCH 02/13] dyndbg: add class_id field and query support
2022-02-17 3:48 [PATCH 00/12] use dynamic-debug under drm.debug api Jim Cromie
2022-02-17 3:48 ` [PATCH 01/13] dyndbg: fix static_branch manipulation Jim Cromie
@ 2022-02-17 3:48 ` Jim Cromie
2022-02-17 3:48 ` [PATCH 03/13] dyndbg: add DEFINE_DYNAMIC_DEBUG_CLASSBITS macro and callbacks Jim Cromie
` (10 subsequent siblings)
12 siblings, 0 replies; 15+ messages in thread
From: Jim Cromie @ 2022-02-17 3:48 UTC (permalink / raw)
To: jbaron, gregkh, linux-kernel, dri-devel, amd-gfx, intel-gvt-dev,
intel-gfx
Cc: daniel.vetter, seanpaul, robdclark, linux, joe, Jim Cromie
DRM defines/uses 10 enum drm_debug_category's to create exclusive
classes of debug messages. To support this directly in dynamic-debug,
add the following:
- struct _ddebug.class_id:4 - 4 bits is enough
- define _DPRINTK_SITE_UNCLASSED 15 - see below
and the query support:
- struct _ddebug_query.class_id
- ddebug_parse_query - looks for "class" keyword, then calls..
- parse_class - accepts uint: 0-15, sets query.class_id and marker
- vpr_info_dq - displays new field
- ddebug_proc_show - append column with "cls:%d" if !UNCLASSED
With the patch, this command enables current/unclassed callsites:
#> echo drm class 15 +p > /proc/dynamic_debug/control
parse_class() accepts 0 .. _DPRINTK_SITE_UNCLASSED, which allows the
>control interface to explicitly manipulate unclassed callsites.
After parsing keywords, ddebug_parse_query() sets .class_id=15, iff it
wasnt explicitly set. This allows future classed/categorized
callsites to be untouched by legacy (class unaware) queries.
DEFINE_DYNAMIC_DEBUG_METADATA gets _CLS(cls,) suffix and arg, and
initializes the new .class_id=cls field. The old name gets the default.
Then, these _CLS(cls,...) modifications are repeated up through the
stack of *dynamic_func_call* macros that use the METADATA initializer,
so as to actually supply the category into it.
NOTES:
_DPRINTK_SITE_UNCLASSED: this symbol is used to initialize all
existing/unclassed pr-debug callsites. Normally, the default would be
zero, but DRM_UT_CORE "uses" that value, in the sense that 0 is
exposed as a bit position in drm.debug. Using 15 allows identity
mapping from category to class, avoiding fiddly offsets.
CC: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
fixup class-id preset
fix2
---
.../admin-guide/dynamic-debug-howto.rst | 7 +++
include/linux/dynamic_debug.h | 54 ++++++++++++++-----
lib/dynamic_debug.c | 38 +++++++++++--
3 files changed, 83 insertions(+), 16 deletions(-)
diff --git a/Documentation/admin-guide/dynamic-debug-howto.rst b/Documentation/admin-guide/dynamic-debug-howto.rst
index a89cfa083155..8ef8d7dcd140 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 number:0-15
* Provides a debugfs control file: ``<debugfs>/dynamic_debug/control``
which can be read to display the complete list of known debug
@@ -143,6 +144,7 @@ against. Possible keywords are:::
'module' string |
'format' string |
'line' line-range
+ 'class' integer:[0-15]
line-range ::= lineno |
'-'lineno |
@@ -217,6 +219,11 @@ line
line -1605 // the 1605 lines from line 1 to line 1605
line 1600- // all lines from line 1600 to the end of the file
+class
+ This expects a single integer in range: 0-15.
+ 15 is used/reserved for existing/unclassed callsites,
+ and is defaulted in unless specified to >control
+
The flags specification comprises a change operation followed
by one or more flag characters. The change operation is one
of the characters::
diff --git a/include/linux/dynamic_debug.h b/include/linux/dynamic_debug.h
index dce631e678dd..d4b48f3cc6e8 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 4
+ unsigned int class_id:CLS_BITS;
+#define _DPRINTK_SITE_UNCLASSED ((1 << CLS_BITS) - 1)
/*
* The flags field controls the behaviour at the callsite.
* The bits here are changed dynamically when the user
@@ -87,7 +92,7 @@ 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, \
@@ -96,8 +101,14 @@ 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_SITE_UNCLASSED, \
+ "classid value overflow")
+
+#define DEFINE_DYNAMIC_DEBUG_METADATA(name, fmt) \
+ DEFINE_DYNAMIC_DEBUG_METADATA_CLS(name, _DPRINTK_SITE_UNCLASSED, fmt)
#ifdef CONFIG_JUMP_LABEL
@@ -128,18 +139,26 @@ 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__); \
+#define __dynamic_func_call_cls(id, cls, fmt, func, ...) do { \
+ DEFINE_DYNAMIC_DEBUG_METADATA_CLS(id, cls, 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); \
- if (DYNAMIC_DEBUG_BRANCH(id)) \
- func(__VA_ARGS__); \
+#define __dynamic_func_call_no_desc_cls(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(id, fmt, func, ...) \
+ __dynamic_func_call_cls(id, _DPRINTK_SITE_UNCLASSED, \
+ fmt, func, ##__VA_ARGS__)
+
+#define __dynamic_func_call_no_desc(id, fmt, func, ...) \
+ __dynamic_func_call_no_desc_cls(id, _DPRINTK_SITE_UNCLASSED, \
+ fmt, func, ##__VA_ARGS__)
+
/*
* "Factory macro" for generating a call to func, guarded by a
* DYNAMIC_DEBUG_BRANCH. The dynamic debug descriptor will be
@@ -148,15 +167,24 @@ 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_SITE_UNCLASSED, 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_no_desc_cls(fmt, cat, func, ...) \
+ __dynamic_func_call_no_desc_cls(__UNIQUE_ID(ddebug), cat, \
+ fmt, func, ##__VA_ARGS__)
+
+#define _dynamic_func_call_no_desc(fmt, func, ...) \
+ __dynamic_func_call_no_desc_cls(__UNIQUE_ID(ddebug), \
+ _DPRINTK_SITE_UNCLASSED, \
+ fmt, func, ##__VA_ARGS__)
#define dynamic_pr_debug(fmt, ...) \
_dynamic_func_call(fmt, __dynamic_pr_debug, \
diff --git a/lib/dynamic_debug.c b/lib/dynamic_debug.c
index a56c1286ffa4..eb3209a7aef0 100644
--- a/lib/dynamic_debug.c
+++ b/lib/dynamic_debug.c
@@ -55,6 +55,8 @@ struct ddebug_query {
const char *function;
const char *format;
unsigned int first_lineno, last_lineno;
+ unsigned int class_id;
+ unsigned int class_marked:1;
};
struct ddebug_iter {
@@ -134,13 +136,13 @@ 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",
+ v3pr_info("%s: func=\"%s\" file=\"%s\" module=\"%s\" format=\"%.*s\" lineno=%u-%u class=%u\n",
msg,
query->function ?: "",
query->filename ?: "",
query->module ?: "",
fmtlen, query->format ?: "",
- query->first_lineno, query->last_lineno);
+ query->first_lineno, query->last_lineno, query->class_id);
}
/*
@@ -170,6 +172,10 @@ static int ddebug_change(const struct ddebug_query *query,
for (i = 0; i < dt->num_ddebugs; i++) {
struct _ddebug *dp = &dt->ddebugs[i];
+ /* match against the class_id, either given or default */
+ if (query->class_id != dp->class_id)
+ continue;
+
/* match against the source filename */
if (query->filename &&
!match_wildcard(query->filename, dp->filename) &&
@@ -308,6 +314,21 @@ static inline int parse_lineno(const char *str, unsigned int *val)
return 0;
}
+static inline int parse_class(struct ddebug_query *query, const char *str)
+{
+ int rc;
+ unsigned int val;
+
+ rc = kstrtouint(str, 10, &val);
+ if (rc < 0 || val > _DPRINTK_SITE_UNCLASSED) {
+ pr_err("expecting class:[0-%d], not %s\n", _DPRINTK_SITE_UNCLASSED, str);
+ return -EINVAL;
+ }
+ query->class_id = val;
+ query->class_marked = 1;
+ return 0;
+}
+
static int parse_linerange(struct ddebug_query *query, const char *first)
{
char *last = strchr(first, '-');
@@ -421,6 +442,9 @@ 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")) {
+ if (parse_class(query, arg))
+ return -EINVAL;
} else {
pr_err("unknown keyword \"%s\"\n", keyword);
return -EINVAL;
@@ -428,6 +452,10 @@ static int ddebug_parse_query(char *words[], int nwords,
if (rc)
return rc;
}
+ /* post-validate the query, set default */
+ if (!query->class_marked)
+ query->class_id = _DPRINTK_SITE_UNCLASSED;
+
vpr_info_dq(query, "parsed");
return 0;
}
@@ -900,7 +928,11 @@ 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(m, dp->format, "\t\r\n\"");
- seq_puts(m, "\"\n");
+ seq_puts(m, "\"");
+
+ if (dp->class_id != _DPRINTK_SITE_UNCLASSED)
+ seq_printf(m, " cls:%u", dp->class_id);
+ seq_puts(m, "\n");
return 0;
}
--
2.35.1
^ permalink raw reply related [flat|nested] 15+ messages in thread* [PATCH 03/13] dyndbg: add DEFINE_DYNAMIC_DEBUG_CLASSBITS macro and callbacks
2022-02-17 3:48 [PATCH 00/12] use dynamic-debug under drm.debug api Jim Cromie
2022-02-17 3:48 ` [PATCH 01/13] dyndbg: fix static_branch manipulation Jim Cromie
2022-02-17 3:48 ` [PATCH 02/13] dyndbg: add class_id field and query support Jim Cromie
@ 2022-02-17 3:48 ` Jim Cromie
2022-02-17 3:48 ` [PATCH 04/13] dyndbg: drop EXPORTed dynamic_debug_exec_queries Jim Cromie
` (9 subsequent siblings)
12 siblings, 0 replies; 15+ messages in thread
From: Jim Cromie @ 2022-02-17 3:48 UTC (permalink / raw)
To: jbaron, gregkh, linux-kernel, dri-devel, amd-gfx, intel-gvt-dev,
intel-gfx
Cc: daniel.vetter, seanpaul, robdclark, linux, joe, Jim Cromie
DEFINE_DYNAMIC_DEBUG_CLASSBITS(fsname, var, bitmap_desc, classes..)
allows users to create a drm.debug style (bitmap) sysfs interface, to
control sets of pr_debug's according to their .class_id's
This wraps existing "class" keyword and behavior:
echo "module drm -p ; module drm class 0 +p ; module drm class 2 +p" >control
With the macro in use, this is equivalent:
echo 0x05 > /sys/module/drm/parameters/debug
To use:
DEFINE_DYNAMIC_DEBUG_CLASSBITS(debug, __drm_debug, "pmfl",
"drm.debug - bits => categories:",
/* vector of uint:4 symbols, ala enum drm_debug_category, 15 is EOL */
DRM_UT_CORE,
DRM_UT_DRIVER,
DRM_UT_KMS ... );
The 3rd arg is a string with any of the dyndbg.flags [pmflt_]+
Full exposure of the flags here lets the module author:
- fully customize/take-over the decorations of enabled sites.
generally leaving decorations to user is preferred.
- aim the debug-stream:
now printk, later tracefs.
generally toggling both together is silly
iface doesnt care about new flags added later
- declare 2 separate sysfs-knobs, one each for p, T, if desired.
- decorations are per callsite,
shared across sysfs-knobs for any controlled classes
To support the macro, the patch adds:
- int param_set_dyndbg_classbits()
- int param_get_dyndbg_classbits()
- struct kernel_param_ops param_ops_dyndbg_classbits
Following the model of kernel/params.c STANDARD_PARAM_DEFS, these are
non-static and exported.
get/set use an augmented kernel_param; the arg refs a new struct
dyndbg_bitmap_param containing:
A- the vector of classes (drm.debug "categories") being controlled
This in-line vector of constants (uint [0-14]) specifies a sequence of
controlling bits (by position, starting at 0) with the values naming
the class_id's mapped to that bit.
A value of _DPRINTK_SITE_UNCLASSED terminates the vector processing by
param_set_dyndbg_classbits(), and is appended by the macro to insure a
defined termination after max 15 classes are applied.
Technically, the vector is a flex-array, but its size is practically
limited to max 15 in length (repeats are pointless).
B- a pointer to the user module's ulong holding the bits/state.
By accessing client's bit-state, we coordinate with existing code
that still uses drm_debug_enabled(), so they work unchanged.
The change to ulong allows use of BIT() etc.
NOTES:
_DPRINTK_SITE_UNCLASSED = 15, ie 2**CLS_BITS-1, deserves special
mention; it already marks all existing pr-debug callsites, only the
new drm.debug callsites are initialized to other (DRM_UT_*) values.
_DPRINTK_SITE_UNCLASSED is used in param_set_dyndbg_classbits() to
limit the range of bits that are processed to what fits in uint:4.
It also terminates the class-id list passed into the macro, so dont
use it halfway through your list of classes-to-control.
param_set_dyndbg_classbits() compares new vs old bits, and only
updates each class on changes. This maximally preserves the
underlying state, which may have been customized at some point via
`echo $cmd >control`. So if users really want to know that all
prdbgs are set precisely, they must pre-clear then set.
Identity mapping in (A) is encouraged. Your vector should exclude 15,
if used, it terminates the list prematurely; any following bit
mappings will be ignored (it is the default/non category).
The whole (A) vector/list passed to the macro is:
- not strictly needed: 0-N bits are scanned, only N is needed in the
macro interface to do this, not the whole list.
- 0-N list allows juggling the bit->class map
Identity map is preferred.
15 terminates list if used. (macro impl does this)
That said, (A) is self-documenting; the explicit list is greppable,
'DRM_UT_*' provides lots of clues. Further, it could be upgraded,
something like:
_pick_sym_(DRM_UT_CORE, "mumble something useful about CORE debug")
_pick_sym_(a,b) a // gives us what we need here
_pick_help_(a,b) #a " : " b // mod-info fodder
Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
---
include/linux/dynamic_debug.h | 50 +++++++++++++++++++++++
lib/dynamic_debug.c | 77 +++++++++++++++++++++++++++++++++++
2 files changed, 127 insertions(+)
diff --git a/include/linux/dynamic_debug.h b/include/linux/dynamic_debug.h
index d4b48f3cc6e8..e83c4e36ad29 100644
--- a/include/linux/dynamic_debug.h
+++ b/include/linux/dynamic_debug.h
@@ -209,6 +209,10 @@ 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_classbits(const char *instr, const struct kernel_param *kp);
+int param_get_dyndbg_classbits(char *buffer, const struct kernel_param *kp);
+
#else /* !CONFIG_DYNAMIC_DEBUG_CORE */
#include <linux/string.h>
@@ -255,6 +259,52 @@ static inline int dynamic_debug_exec_queries(const char *query, const char *modn
return 0;
}
+struct kernel_param;
+static inline int param_set_dyndbg_classbits(const char *instr, const struct kernel_param *kp)
+{ return 0; }
+static inline int param_get_dyndbg_classbits(char *buffer, const struct kernel_param *kp)
+{ return 0; }
+
#endif /* !CONFIG_DYNAMIC_DEBUG_CORE */
+#define FLAGS_LEN 8
+struct dyndbg_classbits_param {
+ unsigned long *bits; /* ref to shared state */
+ const char flags[FLAGS_LEN]; /* toggle these flags on bit-changes */
+ const int classes[]; /* indexed by bitpos */
+};
+
+#if defined(CONFIG_DYNAMIC_DEBUG) || defined(CONFIG_DYNAMIC_DEBUG_CORE)
+/**
+ * DEFINE_DYNAMIC_DEBUG_CLASSBITS() - bitmap control of classed pr_debugs
+ * @sysname: sysfs-node name
+ * @_var: C-identifier holding bit-vector (Bits 0-14 are usable)
+ * @_flgs: string with dyndbg flags: 'p' and/or 'T', and maybe "fmlt" also.
+ * @desc: string summarizing the controls provided
+ * @classes: vector of callsite.class_id's (uint:4, 15 is reserved)
+ *
+ * This macro implements a DRM.debug API style bitmap, mapping bits
+ * 0-14 to classes of prdbg's, as initialized in their .class_id fields.
+ * @_flgs chooses the debug recipient; p - syslog, T - tracefs, and
+ * can include log decorations; m - module, f - function, l - line_num
+ */
+#define DEFINE_DYNAMIC_DEBUG_CLASSBITS(fsname, _var, _flgs, desc, ...) \
+ MODULE_PARM_DESC(fsname, desc); \
+ static struct dyndbg_classbits_param ddcats_##_var = { \
+ .bits = &(_var), \
+ .flags = _flgs, \
+ .classes = { __VA_ARGS__, _DPRINTK_SITE_UNCLASSED } \
+ }; \
+ module_param_cb(fsname, ¶m_ops_dyndbg_classbits, \
+ &ddcats_##_var, 0644)
+
+extern const struct kernel_param_ops param_ops_dyndbg_classbits;
+
+#else /* no dyndbg configured, throw error on macro use */
+
+#define DEFINE_DYNAMIC_DEBUG_CLASSBITS(fsname, var, bitmap_desc, ...) \
+ BUILD_BUG_ON_MSG(1, "CONFIG_DYNAMIC_DEBUG* needed to use this macro: " #fsname)
+
+#endif
+
#endif
diff --git a/lib/dynamic_debug.c b/lib/dynamic_debug.c
index eb3209a7aef0..262178167358 100644
--- a/lib/dynamic_debug.c
+++ b/lib/dynamic_debug.c
@@ -611,6 +611,83 @@ int dynamic_debug_exec_queries(const char *query, const char *modname)
}
EXPORT_SYMBOL_GPL(dynamic_debug_exec_queries);
+#ifdef CONFIG_MODULES
+#define KP_MOD_NAME kp->mod->name
+#else
+#define KP_MOD_NAME NULL /* wildcard */
+#endif
+#define FMT_QUERY_SIZE 128 /* typically need <40 */
+/**
+ * param_set_dyndbg_classbits - bits => categories >control setter
+ * @instr: string echo>d to sysfs
+ * @kp: kp->arg has state: bits, map
+ *
+ * Enable/disable prdbgs by their "category", as specified in the
+ * DEFINE_DYNAMIC_DEBUG_BITGRPS.classbits argument.
+ *
+ * Returns: 0 or <0 if error.
+ */
+int param_set_dyndbg_classbits(const char *instr, const struct kernel_param *kp)
+{
+ unsigned long inbits;
+ int rc, i, matches = 0, totct = 0;
+ char query[FMT_QUERY_SIZE];
+ const struct dyndbg_classbits_param *dcp = kp->arg;
+
+ if (!dcp) {
+ pr_err("set_dyndbg_classbits: no bits=>queries map\n");
+ return -EINVAL;
+ }
+ rc = kstrtoul(instr, 0, &inbits);
+ if (rc) {
+ pr_err("set_dyndbg_classbits: expecting unsigned int\n");
+ return rc;
+ }
+ vpr_info("set_dyndbg_classbits: new 0x%lx old 0x%lx\n", inbits, *dcp->bits);
+
+ for (i = 0; i < _DPRINTK_SITE_UNCLASSED &&
+ dcp->classes[i] < _DPRINTK_SITE_UNCLASSED; i++) {
+
+ if (test_bit(i, &inbits) == test_bit(i, dcp->bits))
+ continue;
+ snprintf(query, FMT_QUERY_SIZE, "class %d %cT", dcp->classes[i],
+ test_bit(i, &inbits) ? '+' : '-');
+
+ matches = ddebug_exec_queries(query, KP_MOD_NAME);
+
+ v2pr_info("bit-%d: %d matches on class:%u\n", i,
+ matches, dcp->classes[i]);
+ totct += matches;
+ }
+ *dcp->bits = inbits;
+ vpr_info("total matches: %d\n", totct);
+ return 0;
+}
+EXPORT_SYMBOL(param_set_dyndbg_classbits);
+
+/**
+ * param_get_dyndbg_classbits - classbits reader
+ * @buffer: string description of controlled bits -> classes
+ * @kp: kp->arg has state: bits, map
+ *
+ * Reads last written bits, underlying prdbg state may have changed since.
+ * Returns: #chars written or <0 on error
+ */
+int param_get_dyndbg_classbits(char *buffer, const struct kernel_param *kp)
+{
+ const struct dyndbg_classbits_param *p = kp->arg;
+ unsigned long val = *p->bits;
+
+ return scnprintf(buffer, PAGE_SIZE, "0x%lx\n", val);
+}
+EXPORT_SYMBOL(param_get_dyndbg_classbits);
+
+const struct kernel_param_ops param_ops_dyndbg_classbits = {
+ .set = param_set_dyndbg_classbits,
+ .get = param_get_dyndbg_classbits,
+};
+EXPORT_SYMBOL(param_ops_dyndbg_classbits);
+
#define PREFIX_SIZE 64
static int remaining(int wrote)
--
2.35.1
^ permalink raw reply related [flat|nested] 15+ messages in thread* [PATCH 04/13] dyndbg: drop EXPORTed dynamic_debug_exec_queries
2022-02-17 3:48 [PATCH 00/12] use dynamic-debug under drm.debug api Jim Cromie
` (2 preceding siblings ...)
2022-02-17 3:48 ` [PATCH 03/13] dyndbg: add DEFINE_DYNAMIC_DEBUG_CLASSBITS macro and callbacks Jim Cromie
@ 2022-02-17 3:48 ` Jim Cromie
2022-02-17 3:48 ` [PATCH 05/13] dyndbg: improve change-info to have old and new Jim Cromie
` (8 subsequent siblings)
12 siblings, 0 replies; 15+ messages in thread
From: Jim Cromie @ 2022-02-17 3:48 UTC (permalink / raw)
To: jbaron, gregkh, linux-kernel, dri-devel, amd-gfx, intel-gvt-dev,
intel-gfx
Cc: daniel.vetter, seanpaul, robdclark, linux, joe, Jim Cromie
This exported fn is effectively obsoleted by Commit:HEAD~2, so remove it.
The export was added here:
commit a2d375eda771 ("dyndbg: refine export, rename to dynamic_debug_exec_queries()")
commit 4c0d77828d4f ("dyndbg: export ddebug_exec_queries")
Its intent was to allow drm.debug to use the exported function to
implement its drm.debug bitmap api using dynamic_debug.
Instead, HEAD~2 implements the bitmap inside dyndbg, and exposes it in
a macro declarator, and HEAD~1 uses the macro to connect __drm_debug
to the supporting callbacks.
Since there are no other expected users, and any prospects would
likely reuse the bitmap or a straightforward extension of it, we can
drop this function until its really needed.
This also drops the CONFIG_DYNAMIC_DEBUG=N stub-func, and its
pr_warn(), which I avoided in 2012, then added in 2020 :-/
Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
---
include/linux/dynamic_debug.h | 9 ---------
lib/dynamic_debug.c | 29 -----------------------------
2 files changed, 38 deletions(-)
diff --git a/include/linux/dynamic_debug.h b/include/linux/dynamic_debug.h
index e83c4e36ad29..664bb83778d2 100644
--- a/include/linux/dynamic_debug.h
+++ b/include/linux/dynamic_debug.h
@@ -60,9 +60,6 @@ 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);
@@ -253,12 +250,6 @@ 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;
-}
-
struct kernel_param;
static inline int param_set_dyndbg_classbits(const char *instr, const struct kernel_param *kp)
{ return 0; }
diff --git a/lib/dynamic_debug.c b/lib/dynamic_debug.c
index 262178167358..b72632212a65 100644
--- a/lib/dynamic_debug.c
+++ b/lib/dynamic_debug.c
@@ -582,35 +582,6 @@ 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);
-
#ifdef CONFIG_MODULES
#define KP_MOD_NAME kp->mod->name
#else
--
2.35.1
^ permalink raw reply related [flat|nested] 15+ messages in thread* [PATCH 05/13] dyndbg: improve change-info to have old and new
2022-02-17 3:48 [PATCH 00/12] use dynamic-debug under drm.debug api Jim Cromie
` (3 preceding siblings ...)
2022-02-17 3:48 ` [PATCH 04/13] dyndbg: drop EXPORTed dynamic_debug_exec_queries Jim Cromie
@ 2022-02-17 3:48 ` Jim Cromie
2022-02-17 3:48 ` [PATCH 06/13] dyndbg: abstract dyndbg_site_is_printing Jim Cromie
` (7 subsequent siblings)
12 siblings, 0 replies; 15+ messages in thread
From: Jim Cromie @ 2022-02-17 3:48 UTC (permalink / raw)
To: jbaron, gregkh, linux-kernel, dri-devel, amd-gfx, intel-gvt-dev,
intel-gfx
Cc: daniel.vetter, seanpaul, robdclark, linux, joe, Jim Cromie
move site.flag update after the v4pr_info("change") message, and
improve the message to print both old and new flag values.
Heres new form:
dyndbg: changed net/ipv4/tcp.c:2424 [tcp]tcp_recvmsg_locked pT -> _
Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
---
lib/dynamic_debug.c | 11 ++++++-----
1 file changed, 6 insertions(+), 5 deletions(-)
diff --git a/lib/dynamic_debug.c b/lib/dynamic_debug.c
index b72632212a65..77db640396a8 100644
--- a/lib/dynamic_debug.c
+++ b/lib/dynamic_debug.c
@@ -158,7 +158,7 @@ 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);
@@ -223,11 +223,12 @@ 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);
--
2.35.1
^ permalink raw reply related [flat|nested] 15+ messages in thread* [PATCH 06/13] dyndbg: abstract dyndbg_site_is_printing
2022-02-17 3:48 [PATCH 00/12] use dynamic-debug under drm.debug api Jim Cromie
` (4 preceding siblings ...)
2022-02-17 3:48 ` [PATCH 05/13] dyndbg: improve change-info to have old and new Jim Cromie
@ 2022-02-17 3:48 ` Jim Cromie
2022-02-17 3:48 ` [PATCH 07/13] drm_print: condense enum drm_debug_category Jim Cromie
` (6 subsequent siblings)
12 siblings, 0 replies; 15+ messages in thread
From: Jim Cromie @ 2022-02-17 3:48 UTC (permalink / raw)
To: jbaron, gregkh, linux-kernel, dri-devel, amd-gfx, intel-gvt-dev,
intel-gfx
Cc: daniel.vetter, seanpaul, robdclark, linux, joe, Jim Cromie
Hide flags test in a macro.
no functional changes.
Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
---
include/linux/dynamic_debug.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/include/linux/dynamic_debug.h b/include/linux/dynamic_debug.h
index 664bb83778d2..106065244f73 100644
--- a/include/linux/dynamic_debug.h
+++ b/include/linux/dynamic_debug.h
@@ -56,7 +56,7 @@ struct _ddebug {
#endif
} __attribute__((aligned(8)));
-
+#define dyndbg_site_is_printing(desc) (desc->flags & _DPRINTK_FLAGS_PRINT)
#if defined(CONFIG_DYNAMIC_DEBUG_CORE)
--
2.35.1
^ permalink raw reply related [flat|nested] 15+ messages in thread* [PATCH 07/13] drm_print: condense enum drm_debug_category
2022-02-17 3:48 [PATCH 00/12] use dynamic-debug under drm.debug api Jim Cromie
` (5 preceding siblings ...)
2022-02-17 3:48 ` [PATCH 06/13] dyndbg: abstract dyndbg_site_is_printing Jim Cromie
@ 2022-02-17 3:48 ` Jim Cromie
2022-02-17 3:48 ` [PATCH 08/13] drm_print: interpose drm_*dbg with forwarding macros Jim Cromie
` (5 subsequent siblings)
12 siblings, 0 replies; 15+ messages in thread
From: Jim Cromie @ 2022-02-17 3:48 UTC (permalink / raw)
To: jbaron, gregkh, linux-kernel, dri-devel, amd-gfx, intel-gvt-dev,
intel-gfx
Cc: daniel.vetter, seanpaul, robdclark, linux, joe, Jim Cromie
enum drm_debug_category has 10 "classes", explicitly initialized with
0x-bitmasks which could be simplified as BIT(X)s. But lets go
further: use natural enumeration (int, starting at 0), and do the
BIT(cat) in drm_debug_enabled(cat) at runtime.
While this slightly pessimizes the bit-test, the category now fits in
4 bits, allowing it in struct _ddebug.class_id:4. This sets us up to
adapt drm to use dyndbg with JUMP_LABEL, thus avoiding all those
bit-tests anyway.
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));
}
/*
--
2.35.1
^ permalink raw reply related [flat|nested] 15+ messages in thread* [PATCH 08/13] drm_print: interpose drm_*dbg with forwarding macros
2022-02-17 3:48 [PATCH 00/12] use dynamic-debug under drm.debug api Jim Cromie
` (6 preceding siblings ...)
2022-02-17 3:48 ` [PATCH 07/13] drm_print: condense enum drm_debug_category Jim Cromie
@ 2022-02-17 3:48 ` Jim Cromie
2022-02-17 3:48 ` [PATCH 09/13] drm_print: wrap drm_*_dbg in dyndbg jumplabel Jim Cromie
` (4 subsequent siblings)
12 siblings, 0 replies; 15+ messages in thread
From: Jim Cromie @ 2022-02-17 3:48 UTC (permalink / raw)
To: jbaron, gregkh, linux-kernel, dri-devel, amd-gfx, intel-gvt-dev,
intel-gfx
Cc: daniel.vetter, seanpaul, robdclark, linux, joe, Jim Cromie
drm_dev_dbg() & drm_dbg() sit below the categorized layer of the DRM
debug API, and implement most of it. These are good places to insert
dynamic-debug jump-label mechanics, allowing DRM to avoid the runtime
cost of drm_debug_enabled().
Set up for this by changing the func names by adding '__' prefixes,
and define forwarding macros to the new names.
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 f783d4963d4b..e45ba224e57c 100644
--- a/drivers/gpu/drm/drm_print.c
+++ b/drivers/gpu/drm/drm_print.c
@@ -256,8 +256,8 @@ 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;
@@ -278,9 +278,9 @@ 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;
@@ -297,7 +297,7 @@ 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 b3b470440e46..4bed99326631 100644
--- a/include/drm/drm_print.h
+++ b/include/drm/drm_print.h
@@ -334,7 +334,7 @@ __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, ...);
/**
@@ -383,6 +383,9 @@ 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
*
@@ -484,10 +487,12 @@ 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, ...) \
--
2.35.1
^ permalink raw reply related [flat|nested] 15+ messages in thread* [PATCH 09/13] drm_print: wrap drm_*_dbg in dyndbg jumplabel
2022-02-17 3:48 [PATCH 00/12] use dynamic-debug under drm.debug api Jim Cromie
` (7 preceding siblings ...)
2022-02-17 3:48 ` [PATCH 08/13] drm_print: interpose drm_*dbg with forwarding macros Jim Cromie
@ 2022-02-17 3:48 ` Jim Cromie
2022-02-17 3:48 ` [PATCH 10/13] drm_print: refine drm_debug_enabled for dyndbg+jump-label Jim Cromie
` (3 subsequent siblings)
12 siblings, 0 replies; 15+ messages in thread
From: Jim Cromie @ 2022-02-17 3:48 UTC (permalink / raw)
To: jbaron, gregkh, linux-kernel, dri-devel, amd-gfx, intel-gvt-dev,
intel-gfx
Cc: daniel.vetter, seanpaul, robdclark, linux, joe, 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 makes the (~4000) callsites controllable, typically by class:
# 0 is DRM_UT_CORE
#> echo module drm class 0 +p > /proc/dynamic_debug/control
=N: keeps direct forwarding: drm_*_dbg -> __drm_*_dbg()
I added the CONFIG_DRM_USE_DYNAMIC_DEBUG item because of the .data
footprint cost of per-callsite control; 56 bytes/site * ~2k,4k
callsites (for i915, amdgpu), which is significant enough that a user
might not want it. Using CONFIG_DYNAMIC_DEBUG_CORE only eliminates
the builtin portion, leaving only drm modules, but still 200k of
module data is a lot.
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 b1f22e457fd0..ec14a1cd4449 100644
--- a/drivers/gpu/drm/Kconfig
+++ b/drivers/gpu/drm/Kconfig
@@ -63,6 +63,18 @@ 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 301a44dc18e3..24e6410d6c0e 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 4bed99326631..06f0ee06be1f 100644
--- a/include/drm/drm_print.h
+++ b/include/drm/drm_print.h
@@ -383,8 +383,14 @@ 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
@@ -491,7 +497,13 @@ 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 */
--
2.35.1
^ permalink raw reply related [flat|nested] 15+ messages in thread* [PATCH 10/13] drm_print: refine drm_debug_enabled for dyndbg+jump-label
2022-02-17 3:48 [PATCH 00/12] use dynamic-debug under drm.debug api Jim Cromie
` (8 preceding siblings ...)
2022-02-17 3:48 ` [PATCH 09/13] drm_print: wrap drm_*_dbg in dyndbg jumplabel Jim Cromie
@ 2022-02-17 3:48 ` Jim Cromie
2022-02-17 3:48 ` [PATCH 11/13] drm_print: prefer bare printk KERN_DEBUG on generic fn Jim Cromie
` (2 subsequent siblings)
12 siblings, 0 replies; 15+ messages in thread
From: Jim Cromie @ 2022-02-17 3:48 UTC (permalink / raw)
To: jbaron, gregkh, linux-kernel, dri-devel, amd-gfx, intel-gvt-dev,
intel-gfx
Cc: daniel.vetter, seanpaul, robdclark, linux, joe, 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 (free of call/NOOP side
effects). 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, it 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 e45ba224e57c..92e6e18026da 100644
--- a/drivers/gpu/drm/drm_print.c
+++ b/drivers/gpu/drm/drm_print.c
@@ -262,7 +262,7 @@ 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);
@@ -285,7 +285,7 @@ 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 06f0ee06be1f..38ef044d786e 100644
--- a/include/drm/drm_print.h
+++ b/include/drm/drm_print.h
@@ -319,11 +319,39 @@ 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
*
--
2.35.1
^ permalink raw reply related [flat|nested] 15+ messages in thread* [PATCH 11/13] drm_print: prefer bare printk KERN_DEBUG on generic fn
2022-02-17 3:48 [PATCH 00/12] use dynamic-debug under drm.debug api Jim Cromie
` (9 preceding siblings ...)
2022-02-17 3:48 ` [PATCH 10/13] drm_print: refine drm_debug_enabled for dyndbg+jump-label Jim Cromie
@ 2022-02-17 3:48 ` Jim Cromie
2022-02-17 3:48 ` [PATCH 12/13] drm_print: add _ddebug desc to drm_*dbg prototypes Jim Cromie
2022-02-17 3:48 ` [PATCH 13/13] drm_print: use DEFINE_DYNAMIC_DEBUG_CLASSBITS for drm.debug Jim Cromie
12 siblings, 0 replies; 15+ messages in thread
From: Jim Cromie @ 2022-02-17 3:48 UTC (permalink / raw)
To: jbaron, gregkh, linux-kernel, dri-devel, amd-gfx, intel-gvt-dev,
intel-gfx
Cc: daniel.vetter, seanpaul, robdclark, linux, joe, 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.
its hardwired on currently
could accidentally: #> echo -p > /proc/dynamic_debug/control
2- optional "decorations" by dyndbg are unhelpful/misleading
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 /lib/modules/5.16.0-rc4-lm1-00008-ged3eac8ceeea/kernel/drivers/gpu/drm/drm.ko
462515 36532 54592 553639 872a7 /lib/modules/5.16.0-rc4-lm1-00009-g6ce0b88d2539-dirty/kernel/drivers/gpu/drm/drm.ko
NB: this was noticed using _drm_debug_enabled(), added earlier.
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 92e6e18026da..24c57b92dc69 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>
@@ -162,7 +160,8 @@ 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);
--
2.35.1
^ permalink raw reply related [flat|nested] 15+ messages in thread* [PATCH 12/13] drm_print: add _ddebug desc to drm_*dbg prototypes
2022-02-17 3:48 [PATCH 00/12] use dynamic-debug under drm.debug api Jim Cromie
` (10 preceding siblings ...)
2022-02-17 3:48 ` [PATCH 11/13] drm_print: prefer bare printk KERN_DEBUG on generic fn Jim Cromie
@ 2022-02-17 3:48 ` Jim Cromie
2022-02-17 3:48 ` [PATCH 13/13] drm_print: use DEFINE_DYNAMIC_DEBUG_CLASSBITS for drm.debug Jim Cromie
12 siblings, 0 replies; 15+ messages in thread
From: Jim Cromie @ 2022-02-17 3:48 UTC (permalink / raw)
To: jbaron, gregkh, linux-kernel, dri-devel, amd-gfx, intel-gvt-dev,
intel-gfx
Cc: daniel.vetter, seanpaul, robdclark, linux, joe, Jim Cromie
Add a struct _ddebug ptr to drm_dbg() and drm_dev_dbg() protos.
And upgrade the current use of _dynamic_func_call_no_desc(); ie drop
the '_no_desc', since the factory macro's callees (these 2 functions)
are now expecting the arg.
This lets those functions act more like pr_debug(). It also means
that these functions don't just get the decorations from an underlying
implementation. DRM already has standards for logging/messaging;
tossing optional decorations on top may not help.
use that info
provide it to dyndbg [1], which can then
control debug enablement and decoration for all those drm.debug
callsites.
For CONFIG_DRM_USE_DYNAMIC_DEBUG=N, just pass null.
NB: desc->class_id is redundant with category, but !!desc dependent.
Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
---
drivers/gpu/drm/drm_print.c | 23 +++++++++++++----------
include/drm/drm_print.h | 23 ++++++++++++-----------
2 files changed, 25 insertions(+), 21 deletions(-)
diff --git a/drivers/gpu/drm/drm_print.c b/drivers/gpu/drm/drm_print.c
index 24c57b92dc69..c9b2a2ab0d3d 100644
--- a/drivers/gpu/drm/drm_print.c
+++ b/drivers/gpu/drm/drm_print.c
@@ -255,8 +255,8 @@ 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;
@@ -264,22 +264,25 @@ 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;
- if (dev)
- dev_printk(KERN_DEBUG, dev, "[" DRM_NAME ":%ps] %pV",
- __builtin_return_address(0), &vaf);
- else
- printk(KERN_DEBUG "[" DRM_NAME ":%ps] %pV",
- __builtin_return_address(0), &vaf);
-
+ if (dev) {
+ if (dyndbg_site_is_printing(desc))
+ dev_printk(KERN_DEBUG, dev, "[" DRM_NAME ":%ps] %pV",
+ __builtin_return_address(0), &vaf);
+ } else {
+ if (dyndbg_site_is_printing(desc))
+ printk(KERN_DEBUG "[" DRM_NAME ":%ps] %pV",
+ __builtin_return_address(0), &vaf);
+ }
va_end(args);
}
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 38ef044d786e..13d52b60f388 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>
@@ -361,9 +362,9 @@ 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, ...);
+__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.
@@ -413,11 +414,11 @@ 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
/**
@@ -520,17 +521,17 @@ 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 */
--
2.35.1
^ permalink raw reply related [flat|nested] 15+ messages in thread* [PATCH 13/13] drm_print: use DEFINE_DYNAMIC_DEBUG_CLASSBITS for drm.debug
2022-02-17 3:48 [PATCH 00/12] use dynamic-debug under drm.debug api Jim Cromie
` (11 preceding siblings ...)
2022-02-17 3:48 ` [PATCH 12/13] drm_print: add _ddebug desc to drm_*dbg prototypes Jim Cromie
@ 2022-02-17 3:48 ` Jim Cromie
12 siblings, 0 replies; 15+ messages in thread
From: Jim Cromie @ 2022-02-17 3:48 UTC (permalink / raw)
To: jbaron, gregkh, linux-kernel, dri-devel, amd-gfx, intel-gvt-dev,
intel-gfx
Cc: daniel.vetter, seanpaul, robdclark, linux, joe, Jim Cromie
if CONFIG_DRM_USE_DYNAMIC_DEBUG=y, use new macro to create the sysfs
bitmap to control drm.debug callsites.
DEFINE_DYNAMIC_DEBUG_CLASSBITS( debug, __drm_debug, "p",
"drm.debug - control summary",
/* inline vector of _ddebug.class_id's to be controlled, max 14 vals */
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 );
NOTES:
The @_flgs used here is "p", so this bitmap enables input to syslog
only, matching legacy behavior.
Also, no "fmlt" decorator flags are used here; that is discouraged, as
it then toggles those flags along with the "p". This would undo any
customizations a user added once the sysfs-knob is used. Still, there
may be cases/reasons.
_ddebug.class_id is uint:4, values 0-14 are valid. 15 is reserved for
non-classified callsites (regular pr_debugs). Using it terminates the
scan, don't use it halfway through your list.
Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
---
drivers/gpu/drm/drm_print.c | 20 ++++++++++++++++++--
include/drm/drm_print.h | 4 ++--
2 files changed, 20 insertions(+), 4 deletions(-)
diff --git a/drivers/gpu/drm/drm_print.c b/drivers/gpu/drm/drm_print.c
index c9b2a2ab0d3d..d916daa384e5 100644
--- a/drivers/gpu/drm/drm_print.c
+++ b/drivers/gpu/drm/drm_print.c
@@ -38,7 +38,7 @@
* __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"
@@ -50,7 +50,23 @@ 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
+DEFINE_DYNAMIC_DEBUG_CLASSBITS(debug, __drm_debug, "p",
+ "enable drm.debug categories - 1 bit per category",
+ 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);
+#endif
void __drm_puts_coredump(struct drm_printer *p, const char *str)
{
diff --git a/include/drm/drm_print.h b/include/drm/drm_print.h
index 13d52b60f388..419140bf992d 100644
--- a/include/drm/drm_print.h
+++ b/include/drm/drm_print.h
@@ -36,7 +36,7 @@
#include <drm/drm.h>
/* Do *not* use outside of drm_print.[ch]! */
-extern unsigned int __drm_debug;
+extern unsigned long __drm_debug;
/**
* DOC: print
@@ -527,7 +527,7 @@ __printf(1, 2)
void __drm_err(const char *format, ...);
#if !defined(CONFIG_DRM_USE_DYNAMIC_DEBUG)
-#define __drm_dbg(fmt, ...) ___drm_dbg(NULL, fmt, ##__VA_ARGS__)
+#define __drm_dbg(cat, fmt, ...) ___drm_dbg(NULL, cat, fmt, ##__VA_ARGS__)
#else
#define __drm_dbg(cat, fmt, ...) \
_dynamic_func_call_cls(cat, fmt, ___drm_dbg, \
--
2.35.1
^ permalink raw reply related [flat|nested] 15+ messages in thread