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base.c
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base.c
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/*
* This code maintains a list of active profiling data structures.
*
* Copyright IBM Corp. 2009
* Author(s): Peter Oberparleiter <[email protected]>
*
* Uses gcc-internal data definitions.
* Based on the gcov-kernel patch by:
* Hubertus Franke <[email protected]>
* Nigel Hinds <[email protected]>
* Rajan Ravindran <[email protected]>
* Peter Oberparleiter <[email protected]>
* Paul Larson
*/
#define pr_fmt(fmt) "gcov: " fmt
#include <linux/init.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include "gcov.h"
static struct gcov_info *gcov_info_head;
static int gcov_events_enabled;
static DEFINE_MUTEX(gcov_lock);
/*
* __gcov_init is called by gcc-generated constructor code for each object
* file compiled with -fprofile-arcs.
*/
void __gcov_init(struct gcov_info *info)
{
static unsigned int gcov_version;
mutex_lock(&gcov_lock);
if (gcov_version == 0) {
gcov_version = info->version;
/*
* Printing gcc's version magic may prove useful for debugging
* incompatibility reports.
*/
pr_info("version magic: 0x%x\n", gcov_version);
}
/*
* Add new profiling data structure to list and inform event
* listener.
*/
info->next = gcov_info_head;
gcov_info_head = info;
if (gcov_events_enabled)
gcov_event(GCOV_ADD, info);
mutex_unlock(&gcov_lock);
}
EXPORT_SYMBOL(__gcov_init);
/*
* These functions may be referenced by gcc-generated profiling code but serve
* no function for kernel profiling.
*/
void __gcov_flush(void)
{
/* Unused. */
}
EXPORT_SYMBOL(__gcov_flush);
void __gcov_merge_add(gcov_type *counters, unsigned int n_counters)
{
/* Unused. */
}
EXPORT_SYMBOL(__gcov_merge_add);
void __gcov_merge_single(gcov_type *counters, unsigned int n_counters)
{
/* Unused. */
}
EXPORT_SYMBOL(__gcov_merge_single);
void __gcov_merge_delta(gcov_type *counters, unsigned int n_counters)
{
/* Unused. */
}
EXPORT_SYMBOL(__gcov_merge_delta);
/**
* gcov_enable_events - enable event reporting through gcov_event()
*
* Turn on reporting of profiling data load/unload-events through the
* gcov_event() callback. Also replay all previous events once. This function
* is needed because some events are potentially generated too early for the
* callback implementation to handle them initially.
*/
void gcov_enable_events(void)
{
struct gcov_info *info;
mutex_lock(&gcov_lock);
gcov_events_enabled = 1;
/* Perform event callback for previously registered entries. */
for (info = gcov_info_head; info; info = info->next)
gcov_event(GCOV_ADD, info);
mutex_unlock(&gcov_lock);
}
#ifdef CONFIG_MODULES
static inline int within(void *addr, void *start, unsigned long size)
{
return ((addr >= start) && (addr < start + size));
}
/* Update list and generate events when modules are unloaded. */
static int gcov_module_notifier(struct notifier_block *nb, unsigned long event,
void *data)
{
struct module *mod = data;
struct gcov_info *info;
struct gcov_info *prev;
if (event != MODULE_STATE_GOING)
return NOTIFY_OK;
mutex_lock(&gcov_lock);
prev = NULL;
/* Remove entries located in module from linked list. */
for (info = gcov_info_head; info; info = info->next) {
if (within(info, mod->module_core, mod->core_size)) {
if (prev)
prev->next = info->next;
else
gcov_info_head = info->next;
if (gcov_events_enabled)
gcov_event(GCOV_REMOVE, info);
} else
prev = info;
}
mutex_unlock(&gcov_lock);
return NOTIFY_OK;
}
static struct notifier_block gcov_nb = {
.notifier_call = gcov_module_notifier,
};
static int __init gcov_init(void)
{
return register_module_notifier(&gcov_nb);
}
device_initcall(gcov_init);
#endif /* CONFIG_MODULES */