Add kernel_param_ops and callbacks to implement a bitmap in a sysfs-node. 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.
get/set use an augmented kernel_param; the arg refs a new struct dyndbg_classes_param, initialized by the macro, containing:
BITS: a pointer to the user module's ulong holding the bits/state. By ref'g the client's bit-state, we coordinate with existing code that uses it, so it works unchanged; for example drm_debug_enabled(). The change to ulong allows use of BIT() etc.
FLAGS: dyndbg.flags toggled by bit-changes. Usually just "p".
MAP: a pointer to struct ddebug_known_classes, which maps those class-names to pr_debug.class_ids 0..N.
Using the sys-node, with dynamic_debug.verbose=1:
bash-5.1# echo 1 > /sys/module/drm/parameters/debug [ 29.821298] dyndbg: set_dyndbg_classes: new 0x1 current 0x0 [ 29.822841] dyndbg: query 0: "class DRM_UT_CORE +p" mod:* [ 29.824348] dyndbg: no matches for query [ 29.825428] dyndbg: total matches: 0
Signed-off-by: Jim Cromie jim.cromie@gmail.com --- include/linux/dynamic_debug.h | 17 ++++++++ lib/dynamic_debug.c | 81 +++++++++++++++++++++++++++++++++++ 2 files changed, 98 insertions(+)
diff --git a/include/linux/dynamic_debug.h b/include/linux/dynamic_debug.h index 328722ba2d8e..e9e6d0f503f3 100644 --- a/include/linux/dynamic_debug.h +++ b/include/linux/dynamic_debug.h @@ -85,6 +85,11 @@ struct ddebug_known_classes_map { .classes = { __VA_ARGS__ } \ }
+struct ddebug_classes_bitmap_param { + unsigned long *bits; + char flags[8]; + const struct ddebug_known_classes_map *map; +};
#if defined(CONFIG_DYNAMIC_DEBUG_CORE)
@@ -237,6 +242,10 @@ void __dynamic_ibdev_dbg(struct _ddebug *descriptor, int dynamic_debug_register_classes(struct ddebug_known_classes_map *map); void dynamic_debug_unregister_classes(struct ddebug_known_classes_map *map);
+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); + #else /* !CONFIG_DYNAMIC_DEBUG_CORE */
#include <linux/string.h> @@ -283,6 +292,14 @@ static inline int dynamic_debug_register_classes(const struct ddebug_known_class static inline void dynamic_debug_unregister_classes(struct ddebug_known_classes_map *map) {}
+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 b1aaf8893cdf..b67bf9efec07 100644 --- a/lib/dynamic_debug.c +++ b/lib/dynamic_debug.c @@ -597,6 +597,87 @@ static int ddebug_exec_queries(char *query, const char *modname) return nfound; }
+static int do_callback_changes(const struct ddebug_classes_bitmap_param *dcp, + int bitpos, unsigned long *inbits) +{ +#define QUERY_SIZE 128 + char query[QUERY_SIZE]; + int matches; + + snprintf(query, QUERY_SIZE, "class %s %c%s", dcp->map->classes[bitpos], + test_bit(bitpos, inbits) ? '+' : '-', dcp->flags); + + matches = ddebug_exec_queries(query, NULL); + + v2pr_info("bit-%d: %d matches on class:%s\n", bitpos, + matches, dcp->map->classes[bitpos]); + + return matches; +} + +/** + * param_set_dyndbg_classes - 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 + * arguments to DEFINE_DYNAMIC_DEBUG_CLASSES. + * + * Returns: 0 or <0 if error. + */ +int param_set_dyndbg_classes(const char *instr, const struct kernel_param *kp) +{ + const struct ddebug_classes_bitmap_param *dcp = kp->arg; + unsigned long inbits; + int rc, i, totct = 0; + + if (!dcp || !dcp->map) { + pr_err("set_dyndbg_classes: no bits=>queries map\n"); + return -EINVAL; + } + rc = kstrtoul(instr, 0, &inbits); + if (rc) { + pr_err("set_dyndbg_classes: expecting bits/integer\n"); + return -EINVAL; + } + vpr_info("set_dyndbg_classes: new 0x%lx current 0x%lx\n", inbits, *dcp->bits); + + for (i = 0; i < dcp->map->length; i++) { + + if (test_bit(i, &inbits) == test_bit(i, dcp->bits)) + continue; + + totct += do_callback_changes(dcp, i, &inbits); + } + *dcp->bits = inbits; + vpr_info("total matches: %d\n", 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 bits, underlying prdbg state may have changed since. + * Returns: #chars written or <0 on error + */ +int param_get_dyndbg_classes(char *buffer, const struct kernel_param *kp) +{ + const struct ddebug_classes_bitmap_param *p = kp->arg; + unsigned long val = *p->bits; + + return scnprintf(buffer, PAGE_SIZE, "0x%lx\n", val); +} +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)