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Using DECLARE_DYNDBG_CLASSMAP, modules can declare up to 31 classnames. By doing so, they authorize dyndbg to manipulate class'd prdbgs (ie: __pr_debug_cls, and soon drm_*dbg), ala:: :#> echo class DRM_UT_KMS +p > /proc/dynamic_debug/control The macro declares and initializes a static struct ddebug_class_map:: - maps approved class-names to class_ids used in module, by array order. forex: DRM_UT_* - class-name vals allow validation of "class FOO" queries using macro is opt-in - enum class_map_type - determines interface, behavior Each module has its own class-type and class_id space, and only known class-names will be authorized for a manipulation. Only DRM modules should know and respont to this: :#> echo class DRM_UT_CORE +p > control # across all modules pr_debugs (with default class_id) are still controllable as before. DECLARE_DYNDBG_CLASSMAP(_var, _maptype, _base, classes...) is:: _var: name of the static struct var. user passes to module_param_cb() if they want a sysfs node. _maptype: this is hard-coded to DD_CLASS_TYPE_DISJOINT_BITS for now. _base: usually 0, it allows splitting 31 classes into subranges, so that multiple classes / sysfs-nodes can share the module's class-id space. classes: list of class_name strings, these are mapped to class-ids starting at _base. This class-names list must have a corresponding ENUM, with SYMBOLS that match the literals, and 1st enum val = _base. enum class_map_type has 4 values, on 2 factors:: - classes are disjoint/independent vs relative/x<y/verbosity. disjoint is basis, verbosity by overlay. - input NUMBERS vs [+-]CLASS_NAMES uints, ideally hex. vs +DRM_UT_CORE,-DRM_UT_KMS DD_CLASS_TYPE_DISJOINT_BITS: classes are separate, one per bit. expecting hex input. built for drm.debug, basis for other types. DD_CLASS_TYPE_DISJOINT_NAMES: input is a CSV of [+-]CLASS_NAMES, classes are independent, like DISJOINT DD_CLASS_TYPE_LEVEL_NUM: input is numeric level, 0-N. 0 implies silence. use printk to break that. relative levels applied on bitmaps. DD_CLASS_TYPE_LEVEL_NAMES: input is a CSV of [+-]CLASS_NAMES, names like: ERR,WARNING,NOTICE,INFO,DEBUG avoiding EMERG,ALERT,CRIT,ERR - no point. NOTES: The macro places the initialized struct ddebug_class_map into the __dyndbg_classes section. That draws an 'orphan' warning which we handle in the next commit. The struct attributes are necessary: __aligned(8) fixed null-ptr derefs, and __used is needed by drm drivers, which declare class-maps, but don't also declare a sysfs-param, and thus dont ref the classmap. The __used insures that the linkage is made, then the class-map is found at load-time. While its possible to handle both NAMES and NUMBERS in the same sys-interface, there is ambiguity to avoid, by disallowing them together. Later, if ambiguities are resolved, 2 new enums can permit both inputs, on verbose & independent types separately, and authors can select the interface style they like. The plan is to implement LEVELS in the callbacks, outside of ddebug_exec_query(), which for simplicity will treat the CLASSES in the map as disjoint. The callbacks can see map-type, and apply ++/-- loops (or bitops) to force the relative meanings across the class-bitmap. RFC: That leaves 2 issues: 1. doing LEVELs in callbacks means that the native >control interface doesn't enforce the LEVELS relationship, so you could confusingly have V3 enabled, but V1 disabled. OTOH, the control iface already allows infinite tweaking of the underlying callsites; sysfs node readback can only tell the user what they previously wrote. 2. All dyndbg >control reduces to a query/command, includes +/-, which is at-root a kernel patching operation with +/- semantics. And the _NAMES handling exposes it to the user, making it API-adjacent. And its not just >control where +/- gets used (which is settled), the new place is with sysfs-nodes exposing _*_NAMES classes, and here its subtly different. _DISJOINT_NAMES: is simple, independent _LEVEL_NAMES: masks-on bits 0 .. N-1, N..max off # turn on L3,L2,L1 others off echo +L3 > /sys/module/test_dynamic_debug/parameters/p_level_names # turn on L2,L1 others off echo -L3 > /sys/module/test_dynamic_debug/parameters/p_level_names IOW, the - changes the threshold-on bitpos by 1. Alternatively, we could treat the +/- as half-duplex, where -L3 turns off L>2 (and ignores L1), and +L2 would turn on L<=2 (and ignore others). Signed-off-by: Jim Cromie <jim.cromie@gmail.com> Link: https://lore.kernel.org/r/20220904214134.408619-15-jim.cromie@gmail.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
327 lines
10 KiB
C
327 lines
10 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef _DYNAMIC_DEBUG_H
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#define _DYNAMIC_DEBUG_H
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#if defined(CONFIG_JUMP_LABEL)
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#include <linux/jump_label.h>
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#endif
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#include <linux/build_bug.h>
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/*
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* An instance of this structure is created in a special
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* ELF section at every dynamic debug callsite. At runtime,
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* the special section is treated as an array of these.
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*/
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struct _ddebug {
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/*
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* These fields are used to drive the user interface
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* for selecting and displaying debug callsites.
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*/
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const char *modname;
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const char *function;
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const char *filename;
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const char *format;
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unsigned int lineno:18;
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#define CLS_BITS 6
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unsigned int class_id:CLS_BITS;
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#define _DPRINTK_CLASS_DFLT ((1 << CLS_BITS) - 1)
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/*
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* The flags field controls the behaviour at the callsite.
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* The bits here are changed dynamically when the user
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* writes commands to <debugfs>/dynamic_debug/control
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*/
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#define _DPRINTK_FLAGS_NONE 0
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#define _DPRINTK_FLAGS_PRINT (1<<0) /* printk() a message using the format */
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#define _DPRINTK_FLAGS_INCL_MODNAME (1<<1)
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#define _DPRINTK_FLAGS_INCL_FUNCNAME (1<<2)
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#define _DPRINTK_FLAGS_INCL_LINENO (1<<3)
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#define _DPRINTK_FLAGS_INCL_TID (1<<4)
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#define _DPRINTK_FLAGS_INCL_ANY \
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(_DPRINTK_FLAGS_INCL_MODNAME | _DPRINTK_FLAGS_INCL_FUNCNAME |\
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_DPRINTK_FLAGS_INCL_LINENO | _DPRINTK_FLAGS_INCL_TID)
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#if defined DEBUG
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#define _DPRINTK_FLAGS_DEFAULT _DPRINTK_FLAGS_PRINT
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#else
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#define _DPRINTK_FLAGS_DEFAULT 0
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#endif
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unsigned int flags:8;
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#ifdef CONFIG_JUMP_LABEL
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union {
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struct static_key_true dd_key_true;
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struct static_key_false dd_key_false;
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} key;
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#endif
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} __attribute__((aligned(8)));
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enum class_map_type {
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DD_CLASS_TYPE_DISJOINT_BITS,
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/**
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* DD_CLASS_TYPE_DISJOINT_BITS: classes are independent, one per bit.
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* expecting hex input. Built for drm.debug, basis for other types.
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*/
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DD_CLASS_TYPE_LEVEL_NUM,
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/**
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* DD_CLASS_TYPE_LEVEL_NUM: input is numeric level, 0-N.
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* N turns on just bits N-1 .. 0, so N=0 turns all bits off.
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*/
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DD_CLASS_TYPE_DISJOINT_NAMES,
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/**
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* DD_CLASS_TYPE_DISJOINT_NAMES: input is a CSV of [+-]CLASS_NAMES,
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* classes are independent, like _DISJOINT_BITS.
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*/
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DD_CLASS_TYPE_LEVEL_NAMES,
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/**
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* DD_CLASS_TYPE_LEVEL_NAMES: input is a CSV of [+-]CLASS_NAMES,
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* intended for names like: INFO,DEBUG,TRACE, with a module prefix
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* avoid EMERG,ALERT,CRIT,ERR,WARNING: they're not debug
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*/
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};
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struct ddebug_class_map {
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struct list_head link;
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struct module *mod;
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const char *mod_name; /* needed for builtins */
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const char **class_names;
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const int length;
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const int base; /* index of 1st .class_id, allows split/shared space */
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enum class_map_type map_type;
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};
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/**
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* DECLARE_DYNDBG_CLASSMAP - declare classnames known by a module
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* @_var: a struct ddebug_class_map, passed to module_param_cb
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* @_type: enum class_map_type, chooses bits/verbose, numeric/symbolic
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* @_base: offset of 1st class-name. splits .class_id space
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* @classes: class-names used to control class'd prdbgs
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*/
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#define DECLARE_DYNDBG_CLASSMAP(_var, _maptype, _base, ...) \
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static const char *_var##_classnames[] = { __VA_ARGS__ }; \
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static struct ddebug_class_map __aligned(8) __used \
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__section("__dyndbg_classes") _var = { \
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.mod = THIS_MODULE, \
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.mod_name = KBUILD_MODNAME, \
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.base = _base, \
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.map_type = _maptype, \
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.length = NUM_TYPE_ARGS(char*, __VA_ARGS__), \
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.class_names = _var##_classnames, \
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}
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#define NUM_TYPE_ARGS(eltype, ...) \
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(sizeof((eltype[]){__VA_ARGS__}) / sizeof(eltype))
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/* encapsulate linker provided built-in (or module) dyndbg data */
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struct _ddebug_info {
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struct _ddebug *descs;
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unsigned int num_descs;
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};
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#if defined(CONFIG_DYNAMIC_DEBUG_CORE)
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int ddebug_add_module(struct _ddebug_info *dyndbg, const char *modname);
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extern int ddebug_remove_module(const char *mod_name);
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extern __printf(2, 3)
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void __dynamic_pr_debug(struct _ddebug *descriptor, const char *fmt, ...);
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extern int ddebug_dyndbg_module_param_cb(char *param, char *val,
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const char *modname);
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struct device;
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extern __printf(3, 4)
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void __dynamic_dev_dbg(struct _ddebug *descriptor, const struct device *dev,
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const char *fmt, ...);
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struct net_device;
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extern __printf(3, 4)
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void __dynamic_netdev_dbg(struct _ddebug *descriptor,
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const struct net_device *dev,
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const char *fmt, ...);
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struct ib_device;
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extern __printf(3, 4)
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void __dynamic_ibdev_dbg(struct _ddebug *descriptor,
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const struct ib_device *ibdev,
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const char *fmt, ...);
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#define DEFINE_DYNAMIC_DEBUG_METADATA_CLS(name, cls, fmt) \
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static struct _ddebug __aligned(8) \
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__section("__dyndbg") name = { \
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.modname = KBUILD_MODNAME, \
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.function = __func__, \
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.filename = __FILE__, \
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.format = (fmt), \
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.lineno = __LINE__, \
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.flags = _DPRINTK_FLAGS_DEFAULT, \
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.class_id = cls, \
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_DPRINTK_KEY_INIT \
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}; \
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BUILD_BUG_ON_MSG(cls > _DPRINTK_CLASS_DFLT, \
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"classid value overflow")
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#define DEFINE_DYNAMIC_DEBUG_METADATA(name, fmt) \
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DEFINE_DYNAMIC_DEBUG_METADATA_CLS(name, _DPRINTK_CLASS_DFLT, fmt)
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#ifdef CONFIG_JUMP_LABEL
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#ifdef DEBUG
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#define _DPRINTK_KEY_INIT .key.dd_key_true = (STATIC_KEY_TRUE_INIT)
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#define DYNAMIC_DEBUG_BRANCH(descriptor) \
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static_branch_likely(&descriptor.key.dd_key_true)
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#else
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#define _DPRINTK_KEY_INIT .key.dd_key_false = (STATIC_KEY_FALSE_INIT)
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#define DYNAMIC_DEBUG_BRANCH(descriptor) \
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static_branch_unlikely(&descriptor.key.dd_key_false)
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#endif
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#else /* !CONFIG_JUMP_LABEL */
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#define _DPRINTK_KEY_INIT
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#ifdef DEBUG
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#define DYNAMIC_DEBUG_BRANCH(descriptor) \
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likely(descriptor.flags & _DPRINTK_FLAGS_PRINT)
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#else
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#define DYNAMIC_DEBUG_BRANCH(descriptor) \
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unlikely(descriptor.flags & _DPRINTK_FLAGS_PRINT)
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#endif
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#endif /* CONFIG_JUMP_LABEL */
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/*
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* Factory macros: ($prefix)dynamic_func_call($suffix)
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*
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* Lower layer (with __ prefix) gets the callsite metadata, and wraps
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* the func inside a debug-branch/static-key construct. Upper layer
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* (with _ prefix) does the UNIQUE_ID once, so that lower can ref the
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* name/label multiple times, and tie the elements together.
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* Multiple flavors:
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* (|_cls): adds in _DPRINT_CLASS_DFLT as needed
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* (|_no_desc): former gets callsite descriptor as 1st arg (for prdbgs)
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*/
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#define __dynamic_func_call_cls(id, cls, fmt, func, ...) do { \
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DEFINE_DYNAMIC_DEBUG_METADATA_CLS(id, cls, fmt); \
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if (DYNAMIC_DEBUG_BRANCH(id)) \
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func(&id, ##__VA_ARGS__); \
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} while (0)
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#define __dynamic_func_call(id, fmt, func, ...) \
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__dynamic_func_call_cls(id, _DPRINTK_CLASS_DFLT, fmt, \
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func, ##__VA_ARGS__)
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#define __dynamic_func_call_cls_no_desc(id, cls, fmt, func, ...) do { \
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DEFINE_DYNAMIC_DEBUG_METADATA_CLS(id, cls, fmt); \
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if (DYNAMIC_DEBUG_BRANCH(id)) \
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func(__VA_ARGS__); \
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} while (0)
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#define __dynamic_func_call_no_desc(id, fmt, func, ...) \
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__dynamic_func_call_cls_no_desc(id, _DPRINTK_CLASS_DFLT, \
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fmt, func, ##__VA_ARGS__)
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/*
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* "Factory macro" for generating a call to func, guarded by a
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* DYNAMIC_DEBUG_BRANCH. The dynamic debug descriptor will be
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* initialized using the fmt argument. The function will be called with
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* the address of the descriptor as first argument, followed by all
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* the varargs. Note that fmt is repeated in invocations of this
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* macro.
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*/
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#define _dynamic_func_call_cls(cls, fmt, func, ...) \
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__dynamic_func_call_cls(__UNIQUE_ID(ddebug), cls, fmt, func, ##__VA_ARGS__)
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#define _dynamic_func_call(fmt, func, ...) \
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_dynamic_func_call_cls(_DPRINTK_CLASS_DFLT, fmt, func, ##__VA_ARGS__)
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/*
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* A variant that does the same, except that the descriptor is not
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* passed as the first argument to the function; it is only called
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* with precisely the macro's varargs.
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*/
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#define _dynamic_func_call_cls_no_desc(cls, fmt, func, ...) \
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__dynamic_func_call_cls_no_desc(__UNIQUE_ID(ddebug), cls, fmt, \
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func, ##__VA_ARGS__)
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#define _dynamic_func_call_no_desc(fmt, func, ...) \
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_dynamic_func_call_cls_no_desc(_DPRINTK_CLASS_DFLT, fmt, \
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func, ##__VA_ARGS__)
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#define dynamic_pr_debug_cls(cls, fmt, ...) \
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_dynamic_func_call_cls(cls, fmt, __dynamic_pr_debug, \
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pr_fmt(fmt), ##__VA_ARGS__)
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#define dynamic_pr_debug(fmt, ...) \
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_dynamic_func_call(fmt, __dynamic_pr_debug, \
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pr_fmt(fmt), ##__VA_ARGS__)
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#define dynamic_dev_dbg(dev, fmt, ...) \
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_dynamic_func_call(fmt, __dynamic_dev_dbg, \
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dev, fmt, ##__VA_ARGS__)
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#define dynamic_netdev_dbg(dev, fmt, ...) \
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_dynamic_func_call(fmt, __dynamic_netdev_dbg, \
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dev, fmt, ##__VA_ARGS__)
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#define dynamic_ibdev_dbg(dev, fmt, ...) \
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_dynamic_func_call(fmt, __dynamic_ibdev_dbg, \
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dev, fmt, ##__VA_ARGS__)
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#define dynamic_hex_dump(prefix_str, prefix_type, rowsize, \
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groupsize, buf, len, ascii) \
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_dynamic_func_call_no_desc(__builtin_constant_p(prefix_str) ? prefix_str : "hexdump", \
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print_hex_dump, \
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KERN_DEBUG, prefix_str, prefix_type, \
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rowsize, groupsize, buf, len, ascii)
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/* for test only, generally expect drm.debug style macro wrappers */
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#define __pr_debug_cls(cls, fmt, ...) do { \
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BUILD_BUG_ON_MSG(!__builtin_constant_p(cls), \
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"expecting constant class int/enum"); \
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dynamic_pr_debug_cls(cls, fmt, ##__VA_ARGS__); \
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} while (0)
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#else /* !CONFIG_DYNAMIC_DEBUG_CORE */
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#include <linux/string.h>
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#include <linux/errno.h>
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#include <linux/printk.h>
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static inline int ddebug_add_module(struct _ddebug_info *dinfo, const char *modname)
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{
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return 0;
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}
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static inline int ddebug_remove_module(const char *mod)
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{
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return 0;
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}
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static inline int ddebug_dyndbg_module_param_cb(char *param, char *val,
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const char *modname)
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{
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if (!strcmp(param, "dyndbg")) {
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/* avoid pr_warn(), which wants pr_fmt() fully defined */
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printk(KERN_WARNING "dyndbg param is supported only in "
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"CONFIG_DYNAMIC_DEBUG builds\n");
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return 0; /* allow and ignore */
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}
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return -EINVAL;
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}
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#define dynamic_pr_debug(fmt, ...) \
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do { if (0) printk(KERN_DEBUG pr_fmt(fmt), ##__VA_ARGS__); } while (0)
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#define dynamic_dev_dbg(dev, fmt, ...) \
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do { if (0) dev_printk(KERN_DEBUG, dev, fmt, ##__VA_ARGS__); } while (0)
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#define dynamic_hex_dump(prefix_str, prefix_type, rowsize, \
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groupsize, buf, len, ascii) \
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do { if (0) \
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print_hex_dump(KERN_DEBUG, prefix_str, prefix_type, \
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rowsize, groupsize, buf, len, ascii); \
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} while (0)
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#endif /* !CONFIG_DYNAMIC_DEBUG_CORE */
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#endif
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