linuxdebug/kernel/gcov/base.c

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2024-07-16 15:50:57 +02:00
// SPDX-License-Identifier: GPL-2.0
/*
* This code maintains a list of active profiling data structures.
*
* Copyright IBM Corp. 2009
* Author(s): Peter Oberparleiter <oberpar@linux.vnet.ibm.com>
*
* Uses gcc-internal data definitions.
* Based on the gcov-kernel patch by:
* Hubertus Franke <frankeh@us.ibm.com>
* Nigel Hinds <nhinds@us.ibm.com>
* Rajan Ravindran <rajancr@us.ibm.com>
* Peter Oberparleiter <oberpar@linux.vnet.ibm.com>
* Paul Larson
*/
#define pr_fmt(fmt) "gcov: " fmt
#include <linux/init.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/sched.h>
#include "gcov.h"
int gcov_events_enabled;
DEFINE_MUTEX(gcov_lock);
/**
* 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 = NULL;
mutex_lock(&gcov_lock);
gcov_events_enabled = 1;
/* Perform event callback for previously registered entries. */
while ((info = gcov_info_next(info))) {
gcov_event(GCOV_ADD, info);
cond_resched();
}
mutex_unlock(&gcov_lock);
}
/**
* store_gcov_u32 - store 32 bit number in gcov format to buffer
* @buffer: target buffer or NULL
* @off: offset into the buffer
* @v: value to be stored
*
* Number format defined by gcc: numbers are recorded in the 32 bit
* unsigned binary form of the endianness of the machine generating the
* file. Returns the number of bytes stored. If @buffer is %NULL, doesn't
* store anything.
*/
size_t store_gcov_u32(void *buffer, size_t off, u32 v)
{
u32 *data;
if (buffer) {
data = buffer + off;
*data = v;
}
return sizeof(*data);
}
/**
* store_gcov_u64 - store 64 bit number in gcov format to buffer
* @buffer: target buffer or NULL
* @off: offset into the buffer
* @v: value to be stored
*
* Number format defined by gcc: numbers are recorded in the 32 bit
* unsigned binary form of the endianness of the machine generating the
* file. 64 bit numbers are stored as two 32 bit numbers, the low part
* first. Returns the number of bytes stored. If @buffer is %NULL, doesn't store
* anything.
*/
size_t store_gcov_u64(void *buffer, size_t off, u64 v)
{
u32 *data;
if (buffer) {
data = buffer + off;
data[0] = (v & 0xffffffffUL);
data[1] = (v >> 32);
}
return sizeof(*data) * 2;
}
#ifdef CONFIG_MODULES
/* 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 = NULL;
struct gcov_info *prev = NULL;
if (event != MODULE_STATE_GOING)
return NOTIFY_OK;
mutex_lock(&gcov_lock);
/* Remove entries located in module from linked list. */
while ((info = gcov_info_next(info))) {
if (gcov_info_within_module(info, mod)) {
gcov_info_unlink(prev, info);
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 */