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 <linux/sched.h> 22 #include "gcov.h" 23 24 static int gcov_events_enabled; 25 static DEFINE_MUTEX(gcov_lock); 26 27 /* 28 * __gcov_init is called by gcc-generated constructor code for each object 29 * file compiled with -fprofile-arcs. 30 */ 31 void __gcov_init(struct gcov_info *info) 32 { 33 static unsigned int gcov_version; 34 35 mutex_lock(&gcov_lock); 36 if (gcov_version == 0) { 37 gcov_version = gcov_info_version(info); 38 /* 39 * Printing gcc's version magic may prove useful for debugging 40 * incompatibility reports. 41 */ 42 pr_info("version magic: 0x%x\n", gcov_version); 43 } 44 /* 45 * Add new profiling data structure to list and inform event 46 * listener. 47 */ 48 gcov_info_link(info); 49 if (gcov_events_enabled) 50 gcov_event(GCOV_ADD, info); 51 mutex_unlock(&gcov_lock); 52 } 53 EXPORT_SYMBOL(__gcov_init); 54 55 /* 56 * These functions may be referenced by gcc-generated profiling code but serve 57 * no function for kernel profiling. 58 */ 59 void __gcov_flush(void) 60 { 61 /* Unused. */ 62 } 63 EXPORT_SYMBOL(__gcov_flush); 64 65 void __gcov_merge_add(gcov_type *counters, unsigned int n_counters) 66 { 67 /* Unused. */ 68 } 69 EXPORT_SYMBOL(__gcov_merge_add); 70 71 void __gcov_merge_single(gcov_type *counters, unsigned int n_counters) 72 { 73 /* Unused. */ 74 } 75 EXPORT_SYMBOL(__gcov_merge_single); 76 77 void __gcov_merge_delta(gcov_type *counters, unsigned int n_counters) 78 { 79 /* Unused. */ 80 } 81 EXPORT_SYMBOL(__gcov_merge_delta); 82 83 void __gcov_merge_ior(gcov_type *counters, unsigned int n_counters) 84 { 85 /* Unused. */ 86 } 87 EXPORT_SYMBOL(__gcov_merge_ior); 88 89 void __gcov_merge_time_profile(gcov_type *counters, unsigned int n_counters) 90 { 91 /* Unused. */ 92 } 93 EXPORT_SYMBOL(__gcov_merge_time_profile); 94 95 void __gcov_merge_icall_topn(gcov_type *counters, unsigned int n_counters) 96 { 97 /* Unused. */ 98 } 99 EXPORT_SYMBOL(__gcov_merge_icall_topn); 100 101 void __gcov_exit(void) 102 { 103 /* Unused. */ 104 } 105 EXPORT_SYMBOL(__gcov_exit); 106 107 /** 108 * gcov_enable_events - enable event reporting through gcov_event() 109 * 110 * Turn on reporting of profiling data load/unload-events through the 111 * gcov_event() callback. Also replay all previous events once. This function 112 * is needed because some events are potentially generated too early for the 113 * callback implementation to handle them initially. 114 */ 115 void gcov_enable_events(void) 116 { 117 struct gcov_info *info = NULL; 118 119 mutex_lock(&gcov_lock); 120 gcov_events_enabled = 1; 121 122 /* Perform event callback for previously registered entries. */ 123 while ((info = gcov_info_next(info))) { 124 gcov_event(GCOV_ADD, info); 125 cond_resched(); 126 } 127 128 mutex_unlock(&gcov_lock); 129 } 130 131 #ifdef CONFIG_MODULES 132 /* Update list and generate events when modules are unloaded. */ 133 static int gcov_module_notifier(struct notifier_block *nb, unsigned long event, 134 void *data) 135 { 136 struct module *mod = data; 137 struct gcov_info *info = NULL; 138 struct gcov_info *prev = NULL; 139 140 if (event != MODULE_STATE_GOING) 141 return NOTIFY_OK; 142 mutex_lock(&gcov_lock); 143 144 /* Remove entries located in module from linked list. */ 145 while ((info = gcov_info_next(info))) { 146 if (within_module((unsigned long)info, mod)) { 147 gcov_info_unlink(prev, info); 148 if (gcov_events_enabled) 149 gcov_event(GCOV_REMOVE, info); 150 } else 151 prev = info; 152 } 153 154 mutex_unlock(&gcov_lock); 155 156 return NOTIFY_OK; 157 } 158 159 static struct notifier_block gcov_nb = { 160 .notifier_call = gcov_module_notifier, 161 }; 162 163 static int __init gcov_init(void) 164 { 165 return register_module_notifier(&gcov_nb); 166 } 167 device_initcall(gcov_init); 168 #endif /* CONFIG_MODULES */ 169