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 struct gcov_info *gcov_info_head; 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 = info->version; 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 info->next = gcov_info_head; 49 gcov_info_head = info; 50 if (gcov_events_enabled) 51 gcov_event(GCOV_ADD, info); 52 mutex_unlock(&gcov_lock); 53 } 54 EXPORT_SYMBOL(__gcov_init); 55 56 /* 57 * These functions may be referenced by gcc-generated profiling code but serve 58 * no function for kernel profiling. 59 */ 60 void __gcov_flush(void) 61 { 62 /* Unused. */ 63 } 64 EXPORT_SYMBOL(__gcov_flush); 65 66 void __gcov_merge_add(gcov_type *counters, unsigned int n_counters) 67 { 68 /* Unused. */ 69 } 70 EXPORT_SYMBOL(__gcov_merge_add); 71 72 void __gcov_merge_single(gcov_type *counters, unsigned int n_counters) 73 { 74 /* Unused. */ 75 } 76 EXPORT_SYMBOL(__gcov_merge_single); 77 78 void __gcov_merge_delta(gcov_type *counters, unsigned int n_counters) 79 { 80 /* Unused. */ 81 } 82 EXPORT_SYMBOL(__gcov_merge_delta); 83 84 /** 85 * gcov_enable_events - enable event reporting through gcov_event() 86 * 87 * Turn on reporting of profiling data load/unload-events through the 88 * gcov_event() callback. Also replay all previous events once. This function 89 * is needed because some events are potentially generated too early for the 90 * callback implementation to handle them initially. 91 */ 92 void gcov_enable_events(void) 93 { 94 struct gcov_info *info; 95 96 mutex_lock(&gcov_lock); 97 gcov_events_enabled = 1; 98 /* Perform event callback for previously registered entries. */ 99 for (info = gcov_info_head; info; info = info->next) 100 gcov_event(GCOV_ADD, info); 101 mutex_unlock(&gcov_lock); 102 } 103 104 #ifdef CONFIG_MODULES 105 static inline int within(void *addr, void *start, unsigned long size) 106 { 107 return ((addr >= start) && (addr < start + size)); 108 } 109 110 /* Update list and generate events when modules are unloaded. */ 111 static int gcov_module_notifier(struct notifier_block *nb, unsigned long event, 112 void *data) 113 { 114 struct module *mod = data; 115 struct gcov_info *info; 116 struct gcov_info *prev; 117 118 if (event != MODULE_STATE_GOING) 119 return NOTIFY_OK; 120 mutex_lock(&gcov_lock); 121 prev = NULL; 122 /* Remove entries located in module from linked list. */ 123 for (info = gcov_info_head; info; info = info->next) { 124 if (within(info, mod->module_core, mod->core_size)) { 125 if (prev) 126 prev->next = info->next; 127 else 128 gcov_info_head = info->next; 129 if (gcov_events_enabled) 130 gcov_event(GCOV_REMOVE, info); 131 } else 132 prev = info; 133 } 134 mutex_unlock(&gcov_lock); 135 136 return NOTIFY_OK; 137 } 138 139 static struct notifier_block gcov_nb = { 140 .notifier_call = gcov_module_notifier, 141 }; 142 143 static int __init gcov_init(void) 144 { 145 return register_module_notifier(&gcov_nb); 146 } 147 device_initcall(gcov_init); 148 #endif /* CONFIG_MODULES */ 149