path: root/arch/um/kernel/time.c

// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright (C) 2015 Anton Ivanov (aivanov@{brocade.com,kot-begemot.co.uk})
 * Copyright (C) 2015 Thomas Meyer (thomas@m3y3r.de)
 * Copyright (C) 2012-2014 Cisco Systems
 * Copyright (C) 2000 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
 * Copyright (C) 2019 Intel Corporation
 */

#include <linux/clockchips.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/jiffies.h>
#include <linux/mm.h>
#include <linux/sched.h>
#include <linux/spinlock.h>
#include <linux/threads.h>
#include <asm/irq.h>
#include <asm/param.h>
#include <kern_util.h>
#include <os.h>
#include <linux/delay.h>
#include <linux/time-internal.h>
#include <linux/um_timetravel.h>
#include <shared/init.h>

#ifdef CONFIG_UML_TIME_TRAVEL_SUPPORT
#include <linux/sched/clock.h>

enum time_travel_mode time_travel_mode;
EXPORT_SYMBOL_GPL(time_travel_mode);

static bool time_travel_start_set;
static unsigned long long time_travel_start;
static unsigned long long time_travel_time;
static unsigned long long time_travel_shm_offset;
static LIST_HEAD(time_travel_events);
static LIST_HEAD(time_travel_irqs);
static unsigned long long time_travel_timer_interval;
static unsigned long long time_travel_next_event;
static struct time_travel_event time_travel_timer_event;
static int time_travel_ext_fd = -1;
static unsigned int time_travel_ext_waiting;
static bool time_travel_ext_prev_request_valid;
static unsigned long long time_travel_ext_prev_request;
static unsigned long long *time_travel_ext_free_until;
static unsigned long long _time_travel_ext_free_until;
static u16 time_travel_shm_id;
static struct um_timetravel_schedshm *time_travel_shm;
static union um_timetravel_schedshm_client *time_travel_shm_client;

unsigned long tt_extra_sched_jiffies;

notrace unsigned long long sched_clock(void)
{
	return (unsigned long long)(jiffies - INITIAL_JIFFIES +
				    tt_extra_sched_jiffies)
					* (NSEC_PER_SEC / HZ);
}

static void time_travel_set_time(unsigned long long ns)
{
	if (unlikely(ns < time_travel_time))
		panic("time-travel: time goes backwards %lld -> %lld\n",
		      time_travel_time, ns);
	else if (unlikely(ns >= S64_MAX))
		panic("The system was going to sleep forever, aborting");

	time_travel_time = ns;
}

enum time_travel_message_handling {
	TTMH_IDLE,
	TTMH_POLL,
	TTMH_READ,
	TTMH_READ_START_ACK,
};

static u64 bc_message;
int time_travel_should_print_bc_msg;

void _time_travel_print_bc_msg(void)
{
	time_travel_should_print_bc_msg = 0;
	printk(KERN_INFO "time-travel: received broadcast 0x%llx\n", bc_message);
}

static void time_travel_setup_shm(int fd, u16 id)
{
	u32 len;

	time_travel_shm = os_mmap_rw_shared(fd, sizeof(*time_travel_shm));

	if (!time_travel_shm)
		goto out;

	len = time_travel_shm->len;

	if (time_travel_shm->version != UM_TIMETRAVEL_SCHEDSHM_VERSION ||
	    len < struct_size(time_travel_shm, clients, id + 1)) {
		os_unmap_memory(time_travel_shm, sizeof(*time_travel_shm));
		time_travel_shm = NULL;
		goto out;
	}

	time_travel_shm = os_mremap_rw_shared(time_travel_shm,
					      sizeof(*time_travel_shm),
					      len);
	if (!time_travel_shm)
		goto out;

	time_travel_shm_offset = time_travel_shm->current_time;
	time_travel_shm_client = &time_travel_shm->clients[id];
	time_travel_shm_client->capa |= UM_TIMETRAVEL_SCHEDSHM_CAP_TIME_SHARE;
	time_travel_shm_id = id;
	/* always look at that free_until from now on */
	time_travel_ext_free_until = &time_travel_shm->free_until;
out:
	os_close_file(fd);
}

static void time_travel_handle_message(struct um_timetravel_msg *msg,
				       enum time_travel_message_handling mode)
{
	struct um_timetravel_msg resp = {
		.op = UM_TIMETRAVEL_ACK,
	};
	int ret;

	/*
	 * We can't unlock here, but interrupt signals with a timetravel_handler
	 * (see um_request_irq