// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Copyright (C) 2001 Anton Blanchard <anton@au.ibm.com>, IBM
 *
 * Communication to userspace based on kernel/printk.c
 */

#include <linux/types.h>
#include <linux/errno.h>
#include <linux/sched.h>
#include <linux/kernel.h>
#include <linux/poll.h>
#include <linux/proc_fs.h>
#include <linux/init.h>
#include <linux/vmalloc.h>
#include <linux/spinlock.h>
#include <linux/cpu.h>
#include <linux/workqueue.h>
#include <linux/slab.h>
#include <linux/topology.h>

#include <linux/uaccess.h>
#include <asm/io.h>
#include <asm/rtas.h>
#include <asm/prom.h>
#include <asm/nvram.h>
#include <linux/atomic.h>
#include <asm/machdep.h>
#include <asm/topology.h>


static DEFINE_SPINLOCK(rtasd_log_lock);

static DECLARE_WAIT_QUEUE_HEAD(rtas_log_wait);

static char *rtas_log_buf;
static unsigned long rtas_log_start;
static unsigned long rtas_log_size;

static int surveillance_timeout = -1;

static unsigned int rtas_error_log_max;
static unsigned int rtas_error_log_buffer_max;

/* RTAS service tokens */
static unsigned int event_scan;
static unsigned int rtas_event_scan_rate;

static bool full_rtas_msgs;

/* Stop logging to nvram after first fatal error */
static int logging_enabled; /* Until we initialize everything,
                             * make sure we don't try logging
                             * anything */
static int error_log_cnt;

/*
 * Since we use 32 bit RTAS, the physical address of this must be below
 * 4G or else bad things happen. Allocate this in the kernel data and
 * make it big enough.
 */
static unsigned char logdata[RTAS_ERROR_LOG_MAX];

static char *rtas_type[] = {
	"Unknown", "Retry", "TCE Error", "Internal Device Failure",
	"Timeout", "Data Parity", "Address Parity", "Cache Parity",
	"Address Invalid", "ECC Uncorrected", "ECC Corrupted",
};

static char *rtas_event_type(int type)
{
	if ((type > 0) && (type < 11))
		return rtas_type[type];

	switch (type) {
		case RTAS_TYPE_EPOW:
			return "EPOW";
		case RTAS_TYPE_PLATFORM:
			return "Platform Error";
		case RTAS_TYPE_IO:
			return "I/O Event";
		case RTAS_TYPE_INFO:
			return "Platform Information Event";
		case RTAS_TYPE_DEALLOC:
			return "Resource Deallocation Event";
		case RTAS_TYPE_DUMP:
			return "Dump Notification Event";
		case RTAS_TYPE_PRRN:
			return "Platform Resource Reassignment Event";
		case RTAS_TYPE_HOTPLUG:
			return "Hotplug Event";
	}

	return rtas_type[0];
}

/* To see this info, grep RTAS /var/log/messages and each entry
 * will be collected together with obvious begin/end.
 * There will be a unique identifier on the begin and end lines.
 * This will persist across reboots.
 *
 * format of error logs returned from RTAS:
 * bytes	(size)	: contents
 * --------------------------------------------------------
 * 0-7		(8)	: rtas_error_log
 * 8-47		(40)	: extended info
 * 48-51	(4)	: vendor id
 * 52-1023 (vendor specific) : location code and debug data
 */
static void printk_log_rtas(char *buf, int len)
{

	int i,j,n = 0;
	int perline = 16;
	char buffer[64];
	char * str = "RTAS event";

	if (full_rtas_msgs) {
		printk(RTAS_DEBUG "%d -------- %s begin --------\n",
		       error_log_cnt, str);

		/*
		 * Print perline bytes on each line, each line will start
		 * with RTAS and a changing number, so syslogd will
		 * print lines that are otherwise the same.  Separate every
		 * 4 bytes with a space.
		 */
		for (i = 0; i < len; i++) {
			j = i % perline;
			if (j == 0) {
				memset(buffer, 0, sizeof(buffer));
				n = sprintf(buffer, "RTAS %d:", i/perline);
			}

			if ((i % 4) == 0)
				n += sprintf(buffer+n, " ");

			n += sprintf(buffer+n, "%02x", (unsigned char)buf[i]);

			if (j == (perline-1))
				printk(KERN_DEBUG "%s\n", buffer);
		}
		if ((i % perline) != 0)
			printk(KERN_DEBUG "%s\n", buffer);

		printk(RTAS_DEBUG "%d -------- %s end ----------\n",
		       error_log_cnt, str);
	} else {
		struct rtas_error_log *errlog = (struct rtas_error_log *)buf;

		printk(RTAS_DEBUG "event: %d, Type: %s (%d), Severity: %d\n",
		       error_log_cnt,
		       rtas_event_type(rtas_error_type(errlog)),
		       rtas_error_type(errlog),
		       rtas_error_severity(errlog));
	}
}

static int log_rtas_len(char * buf)
{
	int len;
	struct rtas_error_log *err;
	uint32_t extended_log_length;

	/* rtas fixed header */
	len = 8;
	err = (struct rtas_error_log *)buf;
	extended_log_length = rtas_error_extended_log_length(err);
	if (rtas_error_extended(err) && extended_log_length) {

		/* extended header */
		len += extended_log_length;
	}

	if (rtas_error_log_max == 0)
		rtas_error_log_max = rtas_get_error_log_max();

	if (len > rtas_error_log_max)
		len = rtas_error_log_max;

	return len;
}

/*
 * First write to nvram, if fatal error, that is the only
 * place we log the info.  The error will be picked up
 * on the next reboot by rtasd.  If not fatal, run the
 * method for the type of error.  Currently, only RTAS
 * errors have methods implemented, but in the future
 * there might be a need to store data in nvram before a
 * call to panic().
 *
 * XXX We write to nvram periodically, to indicate error has
 * been written and sync'd, but there is a possibility
 * that if we don't shutdown correctly, a duplicate error
 * record will be created on next reboot.
 */
void pSeries_log_error(char *buf, unsigned int err_type, int fatal)
{
	unsigned long offset;
	unsigned long s;
	int len = 0;

	pr_debug("rtasd: logging event\n");
	if (buf == NULL)
		return;

	spin_lock_irqsave(&rtasd_log_lock, s);

	/* get length and increase count */
	switch (err_type & ERR_TYPE_MASK) {
	case ERR_TYPE_RTAS_LOG:
		len = log_rtas_len(buf);
		if (!(err_type & ERR_FLAG_BOOT))
			error_log_cnt++;
		break;
	case ERR_TYPE_KERNEL_PANIC:
	default:
		WARN_ON_ONCE(!irqs_disabled()); /* @@@ DEBUG @@@ */
		spin_unlock_irqrestore(&rtasd_log_lock, s);
		return;
	}

#ifdef CONFIG_PPC64
	/* Write error to NVRAM */
	if (logging_enabled && !(err_type & ERR_FLAG_BOOT))
		nvram_write_error_log(buf, len, err_type, error_log_cnt);
#endif /* CONFIG_PPC64 */

	/*
	 * rtas errors can occur during boot, and we do want to capture
	 * those somewhere, even if nvram isn't ready (why not?), and even
	 * if rtasd isn't ready. Put them into the boot log, at least.
	 */
	if ((err_type & ERR_TYPE_MASK) == ERR_TYPE_RTAS_LOG)
		printk_log_rtas(buf, len);

	/* Check to see if we need to or have stopped logging */
	if (fatal || !logging_enabled) {
		logging_enabled = 0;
		WARN_ON_ONCE(!irqs_disabled()); /* @@@ DEBUG @@@ */
		spin_unlock_irqrestore(&rtasd_log_lock, s);
		return;
	}

	/* call type specific method for error */
	switch (err_type & ERR_TYPE_MASK) {
	case ERR_TYPE_RTAS_LOG:
		offset = rtas_error_log_buffer_max *
			((rtas_log_start+rtas_log_size) & LOG_NUMBER_MASK);

		/* First copy over sequence number */
		memcpy(&rtas_log_buf[offset], (void *) &error_log_cnt, sizeof(int));

		/* Second copy over error log data */
		offset += sizeof(int);
		memcpy(&rtas_log_buf[offset], buf, len);

		if (rtas_log_size < LOG_NUMBER)
			rtas_log_size += 1;
		else
			rtas_log_start += 1;

		WARN_ON_ONCE(!irqs_disabled()); /* @@@ DEBUG @@@ */
		spin_unlock_irqrestore(&rtasd_log_lock, s);
		wake_up_interruptible(&rtas_log_wait);
		break;
	case ERR_TYPE_KERNEL_PANIC:
	default:
		WARN_ON_ONCE(!irqs_disabled()); /* @@@ DEBUG @@@ */
		spin_unlock_irqrestore(&rtasd_log_lock, s);
		return;
	}
}

static void handle_rtas_event(const struct rtas_error_log *log)
{
	if (!machine_is(pseries))
		return;

	if (rtas_error_type(log) == RTAS_TYPE_PRRN)
		pr_info_ratelimited("Platform resource reassignment ignored.\n");
}

static int rtas_log_open(struct inode * inode, struct file * file)
{
	return 0;
}

static int rtas_log_release(struct inode * inode, struct file * file)
{
	return 0;
}

/* This will check if all events are logged, if they are then, we
 * know that we can safely clear the events in NVRAM.
 * Next we'll sit and wait for something else to log.
 */
static ssize_t rtas_log_read(struct file * file, char __user * buf,
			 size_t count, loff_t *ppos)
{
	int error;
	char *tmp;
	unsigned long s;
	unsigned long offset;

	if (!buf || count < rtas_error_log_buffer_max)
		return -EINVAL;

	count = rtas_error_log_buffer_max;

	if (!access_ok(buf, count))
		return -EFAULT;

	tmp = kmalloc(count, GFP_KERNEL);
	if (!tmp)
		return -ENOMEM;

	spin_lock_irqsave(&rtasd_log_lock, s);

	/* if it's 0, then we know we got the last one (the one in NVRAM) */
	while (rtas_log_size == 0) {
		if (file->f_flags & O_NONBLOCK) {
			spin_unlock_irqrestore(&rtasd_log_lock, s);
			error = -EAGAIN;
			goto out;
		}

		if (!logging_enabled) {
			spin_unlock_irqrestore(&rtasd_log_lock, s);
			error = -ENODATA;
			goto out;
		}
#ifdef CONFIG_PPC64
		nvram_clear_error_log();
#endif /* CONFIG_PPC64 */

		spin_unlock_irqrestore(&rtasd_log_lock, s);
		error = wait_event_interruptible(rtas_log_wait, rtas_log_size);
		if (error)
			goto out;
		spin_lock_irqsave(&rtasd_log_lock, s);
	}

	offset = rtas_error_log_buffer_max * (rtas_log_start & LOG_NUMBER_MASK);
	memcpy(tmp, &rtas_log_buf[offset], count);

	rtas_log_start += 1;
	rtas_log_size -= 1;
	spin_unlock_irqrestore(&rtasd_log_lock, s);

	error = copy_to_user(buf, tmp, count) ? -EFAULT : count;
out:
	kfree(tmp);
	return error;
}

static __poll_t rtas_log_poll(struct file *file, poll_table * wait)
{
	poll_wait(file, &rtas_log_wait, wait);
	if (rtas_log_size)
		return EPOLLIN | EPOLLRDNORM;
	return 0;
}

static const struct proc_ops rtas_log_proc_ops = {
	.proc_read	= rtas_log_read,
	.proc_poll	= rtas_log_poll,
	.proc_open	= rtas_log_open,
	.proc_release	= rtas_log_release,
	.proc_lseek	= noop_llseek,
};

static int enable_surveillance(int timeout)
{
	int error;

	error = rtas_set_indicator(SURVEILLANCE_TOKEN, 0, timeout);

	if (error == 0)
		return 0;

	if (error == -EINVAL) {
		printk(KERN_DEBUG "rtasd: surveillance not supported\n");
		return 0;
	}

	printk(KERN_ERR "rtasd: could not update surveillance\n");
	return -1;
}

static void do_event_scan(void)
{
	int error;
	do {
		memset(logdata, 0, rtas_error_log_max);
		error = rtas_call(event_scan, 4, 1, NULL,
				  RTAS_EVENT_SCAN_ALL_EVENTS, 0,
				  __pa(logdata), rtas_error_log_max);
		if (error == -1) {
			printk(KERN_ERR "event-scan failed\n");
			break;
		}

		if (error == 0) {
			if (rtas_error_type((struct rtas_error_log *)logdata) !=
			    RTAS_TYPE_PRRN)
				pSeries_log_error(logdata, ERR_TYPE_RTAS_LOG,
						  0);
			handle_rtas_event((struct rtas_error_log *)logdata);
		}

	} while(error == 0);
}

static void rtas_event_scan(struct work_struct *w);
static DECLARE_DELAYED_WORK(event_scan_work, rtas_event_scan);

/*
 * Delay should be at least one second since some machines have problems if
 * we call event-scan too quickly.
 */
static unsigned long event_scan_delay = 1*HZ;
static int first_pass = 1;

static void rtas_event_scan(struct work_struct *w)
{
	unsigned int cpu;

	do_event_scan();

	cpus_read_lock();

	/* raw_ OK because just using CPU as starting point. */
	cpu = cpumask_next(raw_smp_processor_id(), cpu_online_mask);
        if (cpu >= nr_cpu_ids) {
		cpu = cpumask_first(cpu_online_mask);

		if (first_pass) {
			first_pass = 0;
			event_scan_delay = 30*HZ/rtas_event_scan_rate;

			if (surveillance_timeout != -1) {
				pr_debug("rtasd: enabling surveillance\n");
				enable_surveillance(surveillance_timeout);
				pr_debug("rtasd: surveillance enabled\n");
			}
		}
	}

	schedule_delayed_work_on(cpu, &event_scan_work,
		__round_jiffies_relative(event_scan_delay, cpu));

	cpus_read_unlock();
}

#ifdef CONFIG_PPC64
static void retrieve_nvram_error_log(void)
{
	unsigned int err_type ;
	int rc ;

	/* See if we have any error stored in NVRAM */
	memset(logdata, 0, rtas_error_log_max);
	rc = nvram_read_error_log(logdata, rtas_error_log_max,
	                          &err_type, &error_log_cnt);
	/* We can use rtas_log_buf now */
	logging_enabled = 1;
	if (!rc) {
		if (err_type != ERR_FLAG_ALREADY_LOGGED) {
			pSeries_log_error(logdata, err_type | ERR_FLAG_BOOT, 0);
		}
	}
}
#else /* CONFIG_PPC64 */
static void retrieve_nvram_error_log(void)
{
}
#endif /* CONFIG_PPC64 */

static void start_event_scan(void)
{
	printk(KERN_DEBUG "RTAS daemon started\n");
	pr_debug("rtasd: will sleep for %d milliseconds\n",
		 (30000 / rtas_event_scan_rate));

	/* Retrieve errors from nvram if any */
	retrieve_nvram_error_log();

	schedule_delayed_work_on(cpumask_first(cpu_online_mask),
				 &event_scan_work, event_scan_delay);
}

/* Cancel the rtas event scan work */
void rtas_cancel_event_scan(void)
{
	cancel_delayed_work_sync(&event_scan_work);
}
EXPORT_SYMBOL_GPL(rtas_cancel_event_scan);

static int __init rtas_event_scan_init(void)
{
	if (!machine_is(pseries) && !machine_is(chrp))
		return 0;

	/* No RTAS */
	event_scan = rtas_token("event-scan");
	if (event_scan == RTAS_UNKNOWN_SERVICE) {
		printk(KERN_INFO "rtasd: No event-scan on system\n");
		return -ENODEV;
	}

	rtas_event_scan_rate = rtas_token("rtas-event-scan-rate");
	if (rtas_event_scan_rate == RTAS_UNKNOWN_SERVICE) {
		printk(KERN_ERR "rtasd: no rtas-event-scan-rate on system\n");
		return -ENODEV;
	}

	if (!rtas_event_scan_rate) {
		/* Broken firmware: take a rate of zero to mean don't scan */
		printk(KERN_DEBUG "rtasd: scan rate is 0, not scanning\n");
		return 0;
	}

	/* Make room for the sequence number */
	rtas_error_log_max = rtas_get_error_log_max();
	rtas_error_log_buffer_max = rtas_error_log_max + sizeof(int);

	rtas_log_buf = vmalloc(array_size(LOG_NUMBER,
					  rtas_error_log_buffer_max));
	if (!rtas_log_buf) {
		printk(KERN_ERR "rtasd: no memory\n");
		return -ENOMEM;
	}

	start_event_scan();

	return 0;
}
arch_initcall(rtas_event_scan_init);

static int __init rtas_init(void)
{
	struct proc_dir_entry *entry;

	if (!machine_is(pseries) && !machine_is(chrp))
		return 0;

	if (!rtas_log_buf)
		return -ENODEV;

	entry = proc_create("powerpc/rtas/error_log", 0400, NULL,
			    &rtas_log_proc_ops);
	if (!entry)
		printk(KERN_ERR "Failed to create error_log proc entry\n");

	return 0;
}
__initcall(rtas_init);

static int __init surveillance_setup(char *str)
{
	int i;

	/* We only do surveillance on pseries */
	if (!machine_is(pseries))
		return 0;

	if (get_option(&str,&i)) {
		if (i >= 0 && i <= 255)
			surveillance_timeout = i;
	}

	return 1;
}
__setup("surveillance=", surveillance_setup);

static int __init rtasmsgs_setup(char *str)
{
	return (kstrtobool(str, &full_rtas_msgs) == 0);
}
__setup("rtasmsgs=", rtasmsgs_setup);