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
1st, due to a recent commit, this already works:
echo "module drm class 1 +p ; module drm class 3 +p" >control
With the macro, this is basically equivalent:
# this also turns off all other classes. echo 0x05 > /sys/module/drm/parameters/debug
To use:
DEFINE_DYNAMIC_DEBUG_CLASSBITS(debug, __drm_debug, "drm.debug - bits => categories:", /* vector of uint:4 symbols, ala enum drm_debug_category */ DRM_UT_CORE, DRM_UT_DRIVER, DRM_UT_KMS ... );
To support the macro, the patch includes:
- 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
For CONFIG_DRM_USE_DYNDBG=y, enum drm_debug_category is initialized into (struct _ddebug).class_id, so its already available to select on.
B- a pointer to the user module's ulong holding the bits/state.
By sharing bit-state in __drm_debug, we coordinate with existing code that still uses drm_debug_enabled(), so they work unchanged.
NOTES:
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 via later `echo $cmd
control`. So if a user really wants to know that all prdbgs are set
precisely, they must pre-clear then set.
Signed-off-by: Jim Cromie jim.cromie@gmail.com --- include/linux/dynamic_debug.h | 45 ++++++++++++++++++++- lib/dynamic_debug.c | 75 +++++++++++++++++++++++++++++++++++ 2 files changed, 119 insertions(+), 1 deletion(-)
diff --git a/include/linux/dynamic_debug.h b/include/linux/dynamic_debug.h index e9483cd9ac1c..318ac44a0d4a 100644 --- a/include/linux/dynamic_debug.h +++ b/include/linux/dynamic_debug.h @@ -20,7 +20,9 @@ struct _ddebug { const char *function; const char *filename; const char *format; - unsigned int class_id:4; +#define CLS_BITS 4 +#define DD_MAX_CLASSES (1 << CLS_BITS) + unsigned int class_id:CLS_BITS; unsigned int lineno:18; /* * The flags field controls the behaviour at the callsite. @@ -202,6 +204,10 @@ 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> @@ -248,6 +254,43 @@ 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 */
+struct dyndbg_classbits_param { + unsigned long *bits; /* ref to shared state */ + 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 0-15 are usable) + * @desc: string summarizing the controls provided + * @classes: vector of callsite.class_id's (uint:4, 0 is reserved) + * + * This macro implements a DRM.debug API style bitmap, mapping bits + * 0-15 to classes of prdbg's, as initialized in their .class_id fields. + */ +#define DEFINE_DYNAMIC_DEBUG_CLASSBITS(fsname, _var, desc, ...) \ + MODULE_PARM_DESC(fsname, desc); \ + static struct dyndbg_classbits_param ddcats_##_var = { \ + .bits = &(_var), .classes = { __VA_ARGS__, 0 } }; \ + 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|_CORE && -DDYNAMIC_DEBUG_MODULE needed to use this macro: " #fsname #var) + +#endif + #endif diff --git a/lib/dynamic_debug.c b/lib/dynamic_debug.c index 419d4664e724..40ca7973a0f8 100644 --- a/lib/dynamic_debug.c +++ b/lib/dynamic_debug.c @@ -610,6 +610,81 @@ 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 < DD_MAX_CLASSES && dcp->classes[i]; 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)