1 /* 2 * This code maintains a list of active profiling data structures. 3 * 4 * Copyright IBM Corp. 2009 5 * Author(s): Peter Oberparleiter <oberpar@linux.vnet.ibm.com> 6 * 7 * Uses gcc-internal data definitions. 8 * Based on the gcov-kernel patch by: 9 * Hubertus Franke <frankeh@us.ibm.com> 10 * Nigel Hinds <nhinds@us.ibm.com> 11 * Rajan Ravindran <rajancr@us.ibm.com> 12 * Peter Oberparleiter <oberpar@linux.vnet.ibm.com> 13 * Paul Larson 14 */ 15 16 #define pr_fmt(fmt) "gcov: " fmt 17 18 #include <linux/init.h> 19 #include <linux/module.h> 20 #include <linux/mutex.h> 21 #include "gcov.h" 22 23 static int gcov_events_enabled; 24 static DEFINE_MUTEX(gcov_lock); 25 26 /* 27 * __gcov_init is called by gcc-generated constructor code for each object 28 * file compiled with -fprofile-arcs. 29 */ 30 void __gcov_init(struct gcov_info *info) 31 { 32 static unsigned int gcov_version; 33 34 mutex_lock(&gcov_lock); 35 if (gcov_version == 0) { 36 gcov_version = gcov_info_version(info); 37 /* 38 * Printing gcc's version magic may prove useful for debugging 39 * incompatibility reports. 40 */ 41 pr_info("version magic: 0x%x\n", gcov_version); 42 } 43 /* 44 * Add new profiling data structure to list and inform event 45 * listener. 46 */ 47 gcov_info_link(info); 48 if (gcov_events_enabled) 49 gcov_event(GCOV_ADD, info); 50 mutex_unlock(&gcov_lock); 51 } 52 EXPORT_SYMBOL(__gcov_init); 53 54 /* 55 * These functions may be referenced by gcc-generated profiling code but serve 56 * no function for kernel profiling. 57 */ 58 void __gcov_flush(void) 59 { 60 /* Unused. */ 61 } 62 EXPORT_SYMBOL(__gcov_flush); 63 64 void __gcov_merge_add(gcov_type *counters, unsigned int n_counters) 65 { 66 /* Unused. */ 67 } 68 EXPORT_SYMBOL(__gcov_merge_add); 69 70 void __gcov_merge_single(gcov_type *counters, unsigned int n_counters) 71 { 72 /* Unused. */ 73 } 74 EXPORT_SYMBOL(__gcov_merge_single); 75 76 void __gcov_merge_delta(gcov_type *counters, unsigned int n_counters) 77 { 78 /* Unused. */ 79 } 80 EXPORT_SYMBOL(__gcov_merge_delta); 81 82 void __gcov_merge_ior(gcov_type *counters, unsigned int n_counters) 83 { 84 /* Unused. */ 85 } 86 EXPORT_SYMBOL(__gcov_merge_ior); 87 88 /** 89 * gcov_enable_events - enable event reporting through gcov_event() 90 * 91 * Turn on reporting of profiling data load/unload-events through the 92 * gcov_event() callback. Also replay all previous events once. This function 93 * is needed because some events are potentially generated too early for the 94 * callback implementation to handle them initially. 95 */ 96 void gcov_enable_events(void) 97 { 98 struct gcov_info *info = NULL; 99 100 mutex_lock(&gcov_lock); 101 gcov_events_enabled = 1; 102 103 /* Perform event callback for previously registered entries. */ 104 while ((info = gcov_info_next(info))) 105 gcov_event(GCOV_ADD, info); 106 107 mutex_unlock(&gcov_lock); 108 } 109 110 #ifdef CONFIG_MODULES 111 static inline int within(void *addr, void *start, unsigned long size) 112 { 113 return ((addr >= start) && (addr < start + size)); 114 } 115 116 /* Update list and generate events when modules are unloaded. */ 117 static int gcov_module_notifier(struct notifier_block *nb, unsigned long event, 118 void *data) 119 { 120 struct module *mod = data; 121 struct gcov_info *info = NULL; 122 struct gcov_info *prev = NULL; 123 124 if (event != MODULE_STATE_GOING) 125 return NOTIFY_OK; 126 mutex_lock(&gcov_lock); 127 128 /* Remove entries located in module from linked list. */ 129 while ((info = gcov_info_next(info))) { 130 if (within(info, mod->module_core, mod->core_size)) { 131 gcov_info_unlink(prev, info); 132 if (gcov_events_enabled) 133 gcov_event(GCOV_REMOVE, info); 134 } else 135 prev = info; 136 } 137 138 mutex_unlock(&gcov_lock); 139 140 return NOTIFY_OK; 141 } 142 143 static struct notifier_block gcov_nb = { 144 .notifier_call = gcov_module_notifier, 145 }; 146 147 static int __init gcov_init(void) 148 { 149 return register_module_notifier(&gcov_nb); 150 } 151 device_initcall(gcov_init); 152 #endif /* CONFIG_MODULES */ 153