@@ -181,6 +181,10 @@ 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(const char *instr, const struct kernel_param *kp);
+int param_get_dyndbg(char *buffer, const struct kernel_param *kp);
+
#else /* !CONFIG_DYNAMIC_DEBUG_CORE */
#include <linux/string.h>
@@ -227,6 +231,62 @@ static inline int dynamic_debug_exec_queries(const char *query, const char *modn
return 0;
}
+struct kernel_param;
+static inline int param_set_dyndbg(const char *instr, const struct kernel_param *kp)
+{ return 0; }
+static inline int param_get_dyndbg(char *buffer, const struct kernel_param *kp)
+{ return 0; }
+
#endif /* !CONFIG_DYNAMIC_DEBUG_CORE */
+struct dyndbg_bitdesc {
+ /* bitpos is inferred from index in containing array */
+ const char *prefix;
+ const char *help;
+};
+
+struct dyndbg_bitmap_param {
+ unsigned long *bits;
+ struct dyndbg_bitdesc map[];
+};
+
+#if defined(CONFIG_DYNAMIC_DEBUG) || \
+ (defined(CONFIG_DYNAMIC_DEBUG_CORE) && defined(DYNAMIC_DEBUG_MODULE))
+/**
+ * DEFINE_DYNAMIC_DEBUG_CATEGORIES() - bitmap control of categorized prdbgs
+ * @fsname: parameter basename under /sys
+ * @var: C-identifier holding bitmap
+ * @_desc: string summarizing the controls provided
+ * @...: list of struct dyndbg_bitdesc initializations
+ *
+ * Intended for modules with substantial use of "categorized" prdbgs
+ * (those with some systematic prefix in the format string), this lets
+ * modules (using dyndbg) control those prdbg groups according to
+ * their prefixes, and map them to bits 0-N of a sysfs control point.
+ * The @bits... identifies the prefixes to be used by dyndbg to
+ * select and alter those categorized prdbgs, order defines bitpos.
+ */
+#define DEFINE_DYNAMIC_DEBUG_CATEGORIES(fsname, _var, _desc, ...) \
+ MODULE_PARM_DESC(fsname, _desc); \
+ static struct dyndbg_bitmap_param ddcats_##_var = \
+ { .bits = &_var, .map = { __VA_ARGS__, { .prefix = NULL }}}; \
+ module_param_cb(fsname, ¶m_ops_dyndbg, &ddcats_##_var, 0644)
+
+#define _DD_cat_(pfx) { .prefix = pfx, .help = "help for " pfx }
+#define _DD_cat_help_(pfx) "\t " pfx "\t- help for " pfx "\n"
+
+extern const struct kernel_param_ops param_ops_dyndbg;
+
+#elif (defined(CONFIG_DYNAMIC_DEBUG_CORE) && !defined(DYNAMIC_DEBUG_MODULE))
+
+#define DEFINE_DYNAMIC_DEBUG_CATEGORIES(fsname, var, bitmap_desc, ...) \
+ BUILD_BUG_ON_MSG(1, "you need -DDYNAMIC_DEBUG_MODULE in compile")
+
+#else
+#define DEFINE_DYNAMIC_DEBUG_CATEGORIES(fsname, var, bitmap_desc, ...) \
+ BUILD_BUG_ON_MSG(1, "DYNAMIC_DEBUG support required to use this macro: " #var)
+#define _DD_cat_(pfx)
+#define _DD_cat_help_(pfx)
+#endif
+
#endif
@@ -529,7 +529,7 @@ static int ddebug_exec_queries(char *query, const char *modname)
if (!query || !*query || *query == '#')
continue;
- vpr_info("query %d: \"%s\"\n", i, query);
+ vpr_info("query %d: \"%s\" mod:%s\n", i, query, modname ?: "*");
rc = ddebug_exec_query(query, modname);
if (rc < 0) {
@@ -577,6 +577,83 @@ 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 - bits => categories >control setter
+ * @instr: string echo>d to sysfs
+ * @kp: kp->arg has state: bits, map
+ *
+ * Enable/disable prdbgs by their "category", as defined in args to
+ * DEFINE_DYNAMIC_DEBUG_CATEGORIES
+ * Returns: 0 or <0 if error.
+ */
+int param_set_dyndbg(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_bitmap_param *p = kp->arg;
+ const struct dyndbg_bitdesc *map = p->map;
+
+ if (!map) {
+ pr_err("set_dyndbg: no bits=>queries map\n");
+ return -EINVAL;
+ }
+ rc = kstrtoul(instr, 0, &inbits);
+ if (rc) {
+ pr_err("set_dyndbg: failed\n");
+ return rc;
+ }
+ vpr_info("set_dyndbg: new 0x%lx old 0x%lx\n", inbits, *p->bits);
+
+ for (i = 0; map->prefix && i < BITS_PER_LONG; map++, i++) {
+
+ if (test_bit(i, &inbits) == test_bit(i, p->bits))
+ continue;
+ snprintf(query, FMT_QUERY_SIZE, "format '^%s' %cp", map->prefix,
+ test_bit(i, &inbits) ? '+' : '-');
+
+ matches = ddebug_exec_queries(query, KP_MOD_NAME);
+
+ v2pr_info("bit-%d: %d matches on format '^%s'\n", i,
+ matches, map->prefix);
+ totct += matches;
+ }
+ *p->bits = inbits;
+ vpr_info("total matches: %d\n", totct);
+ return 0;
+}
+EXPORT_SYMBOL(param_set_dyndbg);
+
+/**
+ * param_get_dyndbg - bitmap reader
+ * @buffer: receives string rep of bitmap
+ * @kp: kp->arg has state: bits, map
+ *
+ * Reads last written bits, underlying prdbg state may have changed since.
+ * Returns: #chars written
+ */
+int param_get_dyndbg(char *buffer, const struct kernel_param *kp)
+{
+ const struct dyndbg_bitmap_param *p = kp->arg;
+ unsigned long val = *p->bits;
+
+ return scnprintf(buffer, PAGE_SIZE, "0x%lx\n", val);
+}
+EXPORT_SYMBOL(param_get_dyndbg);
+
+const struct kernel_param_ops param_ops_dyndbg = {
+ .set = param_set_dyndbg,
+ .get = param_get_dyndbg,
+};
+/* support DEFINE_DYNAMIC_DEBUG_CATEGORIES users */
+EXPORT_SYMBOL(param_ops_dyndbg);
+
#define PREFIX_SIZE 64
static int remaining(int wrote)
DEFINE_DYNAMIC_DEBUG_CATEGORIES(name, var, bitmap_desc, @bit_descs) allows users to define a drm.debug style (bitmap) sysfs interface, and to specify the desired mapping from bits[0-N] to the format-prefix'd pr_debug()s to be controlled. DEFINE_DYNAMIC_DEBUG_CATEGORIES(debug_gvt, __gvt_debug, "i915/gvt bitmap desc", /** * search-prefixes, passed to dd-exec_queries * defines bits 0-N in order. * leading ^ is tacitly inserted (by callback currently) * trailing space used here excludes subcats. * helper macro needs more work * macro to autogen ++$i, 0x%x$i ? */ _DD_cat_("gvt:cmd: "), _DD_cat_("gvt:core: "), _DD_cat_("gvt:dpy: "), _DD_cat_("gvt:el: "), _DD_cat_("gvt:irq: "), _DD_cat_("gvt:mm: "), _DD_cat_("gvt:mmio: "), _DD_cat_("gvt:render: "), _DD_cat_("gvt:sched: ")); dynamic_debug.c: add 2 new elements: - int param_set_dyndbg() - int param_get_dyndbg() - struct kernel_param_ops param_ops_dyndbg 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: - the map (array, indexed by bitpos) of format-prefix strings, which define the set/category of prdbgs to be changed per each bit. - pointer to the user's ulong holding the bits/state. by sharing state, we coordinate with code that still uses it directly This will allow drm-debug to be converted incrementally, while still using __drm_debug & drm_debug_enabled() in other parts. param_set_dyndbg() compares new vs old bits, and only updates prdbgs on changes. This maximally preserves the underlying state, which may have been customized via later `echo $cmd >control`. So if a user really wants to know that all prdbgs are set precisely, they must pre-clear then set. TLDR: this also doesn't affect the decorator flags "mflt" set per prdbg. dynamic_debug.h: Add DEFINE_DYNAMIC_DEBUG_CATEGORIES() described above, and a stub throwing a BUILD_BUG (RFC) when used without DYNAMIC_DEBUG support. Add structs dyndbg_bitdesc, dyndbg_bitmap_param to support the macro. Note that it also calls MODULE_PARM_DESC for the user, but expects the user to catenate all the bit-descriptions together (as is done in drm.debug), and in the following uses in amdgpu, i915. The intent is to regenerate this output from per-bit help given in VA_ARGS, including a bit_label(); but this can wait. Also externs the struct kernel_param param_ops_dyndbg symbol, as is done in moduleparams.h for all the STANDARD params. USAGE NOTES: Using dyndbg to query on "format ^$prefix" requires that the prefix be present in the compiled-in format string; where run-time prefixing is used, that format would be "%s...", which is not usefully selectable. Using DEFINE_DYNAMIC_DEBUG_CATEGORIES wo support gets a BUILD_BUG. ISTM there is already action at a declarative distance, nobody needs mystery as to why the /sysfs thingy didn't appear. Dyndbg is completely agnostic wrt the categorization scheme used, in order to play well with any prefix convention already in use in the codebase. Ad-hoc categories and sub-categories are implicitly allowed, author discipline and review is expected. Here are some examples: "1","2","3" 2 doesn't imply 1. otherwize, sorta like printk levels "1:","2:","3:" are better, avoiding [1-9]\d+ ambiguity "hi:","mid:","low:" are reasonable, and imply independence "todo:","rfc:","fixme:" might be handy "A:".."Z:" uhm, yeah Hierarchical classes/categories are natural: "drm:<CAT>:" is used in a later commit "drm:<CAT>:<SUB>:" is a natural extension. "drm:atomic:fail:" has been proposed, sounds directly useful NB: in a real sense we abandon enum strictures here, and lose some compiler help, on spelling errs for example. Obviously "drm:" != "DRM:". Some properties of a hierarchical category deserve explication: Trailing spaces matter ! With 1..3-space ("drm: ", "drm:atomic: ", "drm:atomic:fail: "), the ":" doesn't terminate the search-space, the trailing space does. So a "drm:" search spec will match all DRM categories & subcategories, and will not be useful in an interface where all categories are already controlled together. That said, "drm:atomic:" & "drm:atomic: " are different, and both are useful in cases. Ad-Hoc sub-categories: These have a caveat wrt wrapper macros adding prefixes like "drm:atomic: "; the trailing space in the prefix means that drm_dbg_atomic("fail: ...") pastes as "drm:atomic: fail: ", which obviously isn't ideal wrt clear and simple bitmaps. A possible solution is to have a FOO_() version of every FOO() macro which (anti-mnemonically) elides the trailing space, which is normally inserted by a newer FOO(). IE: drm_dbg_atomic_("fail: ..."); // trailing _ means ad-hoc subcat Summarizing: - "drm:kms: " & "drm:kms:" are different - "drm:kms" also different - includes drm:kms2: - "drm:kms:\t" also different - could be troublesome - "drm:kms:*" doesn't work, no wildcard on format atm. Order matters in DEFINE_DYNAMIC_DEBUG_CATEGORIES(... @bit_descs) @bit_descs (array) position determines the bit mapping to the prefix, so to keep a stable map, new categories or 3rd level categories must be added to the end. Since bits are/will-stay applied 0-N, the later bits can countermand the earlier ones, but it's tricky - consider; DD_CATs(... "drm:atomic:", "drm:atomic:fail:" ) // misleading The 1st search-term is misleading, because it includes (modifies) subcategories, but then 2nd overrides it. So don't do that. Signed-off-by: Jim Cromie <jim.cromie@gmail.com> --- v5: . rename to DEFINE_DYNAMIC_DEBUG_CATEGORIES from DEFINE_DYNDBG_BITMAP . in set_dyndbg, replace hardcoded "i915" w kp->mod->name . static inline the stubs . const *str in structs, const array. - Emil . dyndbg: add do-nothing DEFINE_DYNAMIC_DEBUG_CATEGORIES if !DD_CORE . call MOD_PARM_DESC(name, "$desc") for users . simplify callback, remove bit-change detection . config errs reported by <lkp@intel.com> v6: . return rc, bitmap->, snprintf, ws - Andy Shevchenko . s/chgct/matches/ - old varname is misleading . move code off file bottom to a "better" place . change ##fsname to ##var for less generic varname (ie: not "debug") . add KP_MOD_NAME workaround for !CONFIG_MODULES . move forward decl down to where its needed v7: . use kp->arg, dont need kp->data or previous patch-1 - jbaron . use client's ulong for bits, share state . throw BUILD_BUG if DEFINE_DYNAMIC_DEBUG_CATEGORIES used wo support --- include/linux/dynamic_debug.h | 60 ++++++++++++++++++++++++++ lib/dynamic_debug.c | 79 ++++++++++++++++++++++++++++++++++- 2 files changed, 138 insertions(+), 1 deletion(-)