counter_common.c   [plain text]

/* * Copyright (c) 2020 Apple Inc. All rights reserved.
 *
 * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
 *
 * This file contains Original Code and/or Modifications of Original Code
 * as defined in and that are subject to the Apple Public Source License
 * Version 2.0 (the 'License'). You may not use this file except in
 * compliance with the License. The rights granted to you under the License
 * may not be used to create, or enable the creation or redistribution of,
 * unlawful or unlicensed copies of an Apple operating system, or to
 * circumvent, violate, or enable the circumvention or violation of, any
 * terms of an Apple operating system software license agreement.
 *
 * Please obtain a copy of the License at
 * http://www.opensource.apple.com/apsl/ and read it before using this file.
 *
 * The Original Code and all software distributed under the License are
 * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
 * Please see the License for the specific language governing rights and
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 */

#include <kern/assert.h>
#include <kern/cpu_data.h>
#include <kern/counter.h>
#include <kern/zalloc.h>
#include <machine/atomic.h>
#include <machine/machine_routines.h>
#include <machine/cpu_number.h>

SECURITY_READ_ONLY_LATE(zone_t) counters_zone;
ZONE_INIT(&counters_zone, "per_cpu_counters", sizeof(uint64_t),
    ZC_PERCPU | ZC_ALIGNMENT_REQUIRED, ZONE_ID_ANY, NULL);

/*
 * Tracks how many static scalable counters are in use since they won't show up
 * in the per_cpu_counters zone stats.
 */
uint64_t num_static_scalable_counters;

/*
 * Mangle the given scalable_counter_t so that it points to the early storage
 * regardless of which CPU # we're boot on.
 * Must be run before we go multi-core.
 */
__startup_func void
scalable_counter_static_boot_mangle(scalable_counter_t *counter)
{
	*counter = __zpcpu_mangle_for_boot(*counter);
}

/*
 * Initializes a static counter in permanent per-cpu memory.
 * Run during startup for each static per-cpu counter
 * Must be run before we go multi-core.
 */
__startup_func void
scalable_counter_static_init(scalable_counter_t *counter)
{
	/*
	 * We pointed the counter to a single global value during early boot.
	 * Grab that value now. We'll store it in our current CPU's value
	 */
	uint64_t current_value = os_atomic_load_wide(zpercpu_get(*counter), relaxed);
	/*
	 * This counter can't be freed so we allocate it out of the permanent zone rather than
	 * our counter zone.
	 */
	*counter = zalloc_percpu_permanent(sizeof(uint64_t), ZALIGN_64);
	os_atomic_store_wide(zpercpu_get(*counter), current_value, relaxed);
	num_static_scalable_counters++;
}

OS_OVERLOADABLE
void
counter_alloc(scalable_counter_t *counter)
{
	*counter = zalloc_percpu(counters_zone, Z_WAITOK | Z_ZERO | Z_NOFAIL);
}

OS_OVERLOADABLE
void
counter_alloc(atomic_counter_t *counter)
{
	os_atomic_store_wide(counter, 0, relaxed);
}

OS_OVERLOADABLE
void
counter_free(scalable_counter_t *counter)
{
	zfree_percpu(counters_zone, *counter);
}

OS_OVERLOADABLE
void
counter_free(atomic_counter_t *counter)
{
	(void)counter;
}

OS_OVERLOADABLE
void
counter_add(atomic_counter_t *counter, uint64_t amount)
{
	os_atomic_add(counter, amount, relaxed);
}

OS_OVERLOADABLE
void
counter_inc(atomic_counter_t *counter)
{
	os_atomic_inc(counter, relaxed);
}

OS_OVERLOADABLE
void
counter_dec(atomic_counter_t *counter)
{
	os_atomic_dec(counter, relaxed);
}

OS_OVERLOADABLE
void
counter_add_preemption_disabled(atomic_counter_t *counter, uint64_t amount)
{
	counter_add(counter, amount);
}

OS_OVERLOADABLE
void
counter_inc_preemption_disabled(atomic_counter_t *counter)
{
	counter_inc(counter);
}

OS_OVERLOADABLE
void
counter_dec_preemption_disabled(atomic_counter_t *counter)
{
	counter_dec(counter);
}

OS_OVERLOADABLE
uint64_t
counter_load(atomic_counter_t *counter)
{
	return os_atomic_load_wide(counter, relaxed);
}

OS_OVERLOADABLE
uint64_t
counter_load(scalable_counter_t *counter)
{
	uint64_t value = 0;
	zpercpu_foreach(it, *counter) {
		value += os_atomic_load_wide(it, relaxed);
	}
	return value;
}