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 /** 83 * gcov_enable_events - enable event reporting through gcov_event() 84 * 85 * Turn on reporting of profiling data load/unload-events through the 86 * gcov_event() callback. Also replay all previous events once. This function 87 * is needed because some events are potentially generated too early for the 88 * callback implementation to handle them initially. 89 */ 90 void gcov_enable_events(void) 91 { 92 struct gcov_info *info = NULL; 93 94 mutex_lock(&gcov_lock); 95 gcov_events_enabled = 1; 96 97 /* Perform event callback for previously registered entries. */ 98 while ((info = gcov_info_next(info))) 99 gcov_event(GCOV_ADD, info); 100 101 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 = NULL; 116 struct gcov_info *prev = NULL; 117 118 if (event != MODULE_STATE_GOING) 119 return NOTIFY_OK; 120 mutex_lock(&gcov_lock); 121 122 /* Remove entries located in module from linked list. */ 123 while ((info = gcov_info_next(info))) { 124 if (within(info, mod->module_core, mod->core_size)) { 125 gcov_info_unlink(prev, info); 126 if (gcov_events_enabled) 127 gcov_event(GCOV_REMOVE, info); 128 } else 129 prev = info; 130 } 131 132 mutex_unlock(&gcov_lock); 133 134 return NOTIFY_OK; 135 } 136 137 static struct notifier_block gcov_nb = { 138 .notifier_call = gcov_module_notifier, 139 }; 140 141 static int __init gcov_init(void) 142 { 143 return register_module_notifier(&gcov_nb); 144 } 145 device_initcall(gcov_init); 146 #endif /* CONFIG_MODULES */ 147