[deliverable/linux.git] / drivers / tty / hvc / hvc_xen.c

/*
 * xen console driver interface to hvc_console.c
 *
 * (c) 2007 Gerd Hoffmann <kraxel@suse.de>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
 */

#include <linux/console.h>
#include <linux/delay.h>
#include <linux/err.h>
#include <linux/irq.h>
#include <linux/init.h>
#include <linux/types.h>
#include <linux/list.h>

#include <asm/io.h>
#include <asm/xen/hypervisor.h>

#include <xen/xen.h>
#include <xen/interface/xen.h>
#include <xen/hvm.h>
#include <xen/grant_table.h>
#include <xen/page.h>
#include <xen/events.h>
#include <xen/interface/io/console.h>
#include <xen/interface/sched.h>
#include <xen/hvc-console.h>
#include <xen/xenbus.h>

#include "hvc_console.h"

#define HVC_COOKIE   0x58656e /* "Xen" in hex */

struct xencons_info {
	struct list_head list;
	struct xenbus_device *xbdev;
	struct xencons_interface *intf;
	unsigned int evtchn;
	struct hvc_struct *hvc;
	int irq;
	int vtermno;
	grant_ref_t gntref;
};

static LIST_HEAD(xenconsoles);
static DEFINE_SPINLOCK(xencons_lock);

/* ------------------------------------------------------------------ */

static struct xencons_info *vtermno_to_xencons(int vtermno)
{
	struct xencons_info *entry, *n, *ret = NULL;

	if (list_empty(&xenconsoles))
			return NULL;

	list_for_each_entry_safe(entry, n, &xenconsoles, list) {
		if (entry->vtermno == vtermno) {
			ret  = entry;
			break;
		}
	}

	return ret;
}

static inline int xenbus_devid_to_vtermno(int devid)
{
	return devid + HVC_COOKIE;
}

static inline void notify_daemon(struct xencons_info *cons)
{
	/* Use evtchn: this is called early, before irq is set up. */
	notify_remote_via_evtchn(cons->evtchn);
}

static int __write_console(struct xencons_info *xencons,
		const char *data, int len)
{
	XENCONS_RING_IDX cons, prod;
	struct xencons_interface *intf = xencons->intf;
	int sent = 0;

	cons = intf->out_cons;
	prod = intf->out_prod;
	mb();			/* update queue values before going on */
	BUG_ON((prod - cons) > sizeof(intf->out));

	while ((sent < len) && ((prod - cons) < sizeof(intf->out)))
		intf->out[MASK_XENCONS_IDX(prod++, intf->out)] = data[sent++];

	wmb();			/* write ring before updating pointer */
	intf->out_prod = prod;

	if (sent)
		notify_daemon(xencons);
	return sent;
}

static int domU_write_console(uint32_t vtermno, const char *data, int len)
{
	int ret = len;
	struct xencons_info *cons = vtermno_to_xencons(vtermno);
	if (cons == NULL)
		return -EINVAL;

	/*
	 * Make sure the whole buffer is emitted, polling if
	 * necessary.  We don't ever want to rely on the hvc daemon
	 * because the most interesting console output is when the
	 * kernel is crippled.
	 */
	while (len) {
		int sent = __write_console(cons, data, len);
		
		data += sent;
		len -= sent;

		if (unlikely(len))
			HYPERVISOR_sched_op(SCHEDOP_yield, NULL);
	}

	return ret;
}

static int domU_read_console(uint32_t vtermno, char *buf, int len)
{
	struct xencons_interface *intf;
	XENCONS_RING_IDX cons, prod;
	int recv = 0;
	struct xencons_info *xencons = vtermno_to_xencons(vtermno);
	if (xencons == NULL)
		return -EINVAL;
	intf = xencons->intf;

	cons = intf->in_cons;
	prod = intf->in_prod;
	mb();			/* get pointers before reading ring */
	BUG_ON((prod - cons) > sizeof(intf->in));

	while (cons != prod && recv < len)
		buf[recv++] = intf->in[MASK_XENCONS_IDX(cons++, intf->in)];

	mb();			/* read ring before consuming */
	intf->in_cons = cons;

	notify_daemon(xencons);
	return recv;
}

static struct hv_ops domU_hvc_ops = {
	.get_chars = domU_read_console,
	.put_chars = domU_write_console,
	.notifier_add = notifier_add_irq,
	.notifier_del = notifier_del_irq,
	.notifier_hangup = notifier_hangup_irq,
};

static int dom0_read_console(uint32_t vtermno, char *buf, int len)
{
	return HYPERVISOR_console_io(CONSOLEIO_read, len, buf);
}

/*
 * Either for a dom0 to write to the system console, or a domU with a
 * debug version of Xen
 */
static int dom0_write_console(uint32_t vtermno, const char *str, int len)
{
	int rc = HYPERVISOR_console_io(CONSOLEIO_write, len, (char *)str);
	if (rc < 0)
		return rc;

	return len;
}

static struct hv_ops dom0_hvc_ops = {
	.get_chars = dom0_read_console,
	.put_chars = dom0_write_console,
	.notifier_add = notifier_add_irq,
	.notifier_del = notifier_del_irq,
	.notifier_hangup = notifier_hangup_irq,
};

static int xen_hvm_console_init(void)
{
	int r;
	uint64_t v = 0;
	unsigned long mfn;
	struct xencons_info *info;

	if (!xen_hvm_domain())
		return -ENODEV;

	info = vtermno_to_xencons(HVC_COOKIE);
	if (!info) {
		info = kzalloc(sizeof(struct xencons_info), GFP_KERNEL);
		if (!info)
			return -ENOMEM;
	} else if (info->intf != NULL) {
		/* already configured */
		return 0;
	}
	/*
	 * If the toolstack (or the hypervisor) hasn't set these values, the
	 * default value is 0. Even though mfn = 0 and evtchn = 0 are
	 * theoretically correct values, in practice they never are and they
	 * mean that a legacy toolstack hasn't initialized the pv console correctly.
	 */
	r = hvm_get_parameter(HVM_PARAM_CONSOLE_EVTCHN, &v);
	if (r < 0 || v == 0)
		goto err;
	info->evtchn = v;
	v = 0;
	r = hvm_get_parameter(HVM_PARAM_CONSOLE_PFN, &v);
	if (r < 0 || v == 0)
		goto err;
	mfn = v;
	info->intf = xen_remap(mfn << PAGE_SHIFT, PAGE_SIZE);
	if (info->intf == NULL)
		goto err;
	info->vtermno = HVC_COOKIE;

	spin_lock(&xencons_lock);
	list_add_tail(&info->list, &xenconsoles);
	spin_unlock(&xencons_lock);

	return 0;
err:
	kfree(info);
	return -ENODEV;
}

static int xen_pv_console_init(void)
{
	struct xencons_info *info;

	if (!xen_pv_domain())
		return -ENODEV;

	if (!xen_start_info->console.domU.evtchn)
		return -ENODEV;

	info = vtermno_to_xencons(HVC_COOKIE);
	if (!info) {
		info = kzalloc(sizeof(struct xencons_info), GFP_KERNEL);
		if (!info)
			return -ENOMEM;
	} else if (info->intf != NULL) {
		/* already configured */
		return 0;
	}
	info->evtchn = xen_start_info->console.domU.evtchn;
	info->intf = mfn_to_virt(xen_start_info->console.domU.mfn);
	info->vtermno = HVC_COOKIE;

	spin_lock(&xencons_lock);
	list_add_tail(&info->list, &xenconsoles);
	spin_unlock(&xencons_lock);

	return 0;
}

static int xen_initial_domain_console_init(void)
{
	struct xencons_info *info;

	if (!xen_initial_domain())
		return -ENODEV;

	info = vtermno_to_xencons(HVC_COOKIE);
	if (!info) {
		info = kzalloc(sizeof(struct xencons_info), GFP_KERNEL);
		if (!info)
			return -ENOMEM;
	}

	info->irq = bind_virq_to_irq(VIRQ_CONSOLE, 0);
	info->vtermno = HVC_COOKIE;

	spin_lock(&xencons_lock);
	list_add_tail(&info->list, &xenconsoles);
	spin_unlock(&xencons_lock);

	return 0;
}

void xen_console_resume(void)
{
	struct xencons_info *info = vtermno_to_xencons(HVC_COOKIE);
	if (info != NULL && info->irq)
		rebind_evtchn_irq(info->evtchn, info->irq);
}

static void xencons_disconnect_backend(struct xencons_info *info)
{
	if (info->irq > 0)
		unbind_from_irqhandler(info->irq, NULL);
	info->irq = 0;
	if (info->evtchn > 0)
		xenbus_free_evtchn(info->xbdev, info->evtchn);
	info->evtchn = 0;
	if (info->gntref > 0)
		gnttab_free_grant_references(info->gntref);
	info->gntref = 0;
	if (info->hvc != NULL)
		hvc_remove(info->hvc);
	info->hvc = NULL;
}

static void xencons_free(struct xencons_info *info)
{
	free_page((unsigned long)info->intf);
	info->intf = NULL;
	info->vtermno = 0;
	kfree(info);
}

static int xen_console_remove(struct xencons_info *info)
{
	xencons_disconnect_backend(info);
	spin_lock(&xencons_lock);
	list_del(&info->list);
	spin_unlock(&xencons_lock);
	if (info->xbdev != NULL)
		xencons_free(info);
	else {
		if (xen_hvm_domain())
			iounmap(info->intf);
		kfree(info);
	}
	return 0;
}

#ifdef CONFIG_HVC_XEN_FRONTEND
static struct xenbus_driver xencons_driver;

static int xencons_remove(struct xenbus_device *dev)
{
	return xen_console_remove(dev_get_drvdata(&dev->dev));
}

static int xencons_connect_backend(struct xenbus_device *dev,
				  struct xencons_info *info)
{
	int ret, evtchn, devid, ref, irq;
	struct xenbus_transaction xbt;
	grant_ref_t gref_head;
	unsigned long mfn;

	ret = xenbus_alloc_evtchn(dev, &evtchn);
	if (ret)
		return ret;
	info->evtchn = evtchn;
	irq = bind_evtchn_to_irq(evtchn);
	if (irq < 0)
		return irq;
	info->irq = irq;
	devid = dev->nodename[strlen(dev->nodename) - 1] - '0';
	info->hvc = hvc_alloc(xenbus_devid_to_vtermno(devid),
			irq, &domU_hvc_ops, 256);
	if (IS_ERR(info->hvc))
		return PTR_ERR(info->hvc);
	if (xen_pv_domain())
		mfn = virt_to_mfn(info->intf);
	else
		mfn = __pa(info->intf) >> PAGE_SHIFT;
	ret = gnttab_alloc_grant_references(1, &gref_head);
	if (ret < 0)
		return ret;
	info->gntref = gref_head;
	ref = gnttab_claim_grant_reference(&gref_head);
	if (ref < 0)
		return ref;
	gnttab_grant_foreign_access_ref(ref, info->xbdev->otherend_id,
			mfn, 0);

 again:
	ret = xenbus_transaction_start(&xbt);
	if (ret) {
		xenbus_dev_fatal(dev, ret, "starting transaction");
		return ret;
	}
	ret = xenbus_printf(xbt, dev->nodename, "ring-ref", "%d", ref);
	if (ret)
		goto error_xenbus;
	ret = xenbus_printf(xbt, dev->nodename, "port", "%u",
			    evtchn);
	if (ret)
		goto error_xenbus;
	ret = xenbus_printf(xbt, dev->nodename, "type", "ioemu");
	if (ret)
		goto error_xenbus;
	ret = xenbus_transaction_end(xbt, 0);
	if (ret) {
		if (ret == -EAGAIN)
			goto again;
		xenbus_dev_fatal(dev, ret, "completing transaction");
		return ret;
	}

	xenbus_switch_state(dev, XenbusStateInitialised);
	return 0;

 error_xenbus:
	xenbus_transaction_end(xbt, 1);
	xenbus_dev_fatal(dev, ret, "writing xenstore");
	return ret;
}

static int xencons_probe(struct xenbus_device *dev,
				  const struct xenbus_device_id *id)
{
	int ret, devid;
	struct xencons_info *info;

	devid = dev->nodename[strlen(dev->nodename) - 1] - '0';
	if (devid == 0)
		return -ENODEV;

	info = kzalloc(sizeof(struct xencons_info), GFP_KERNEL);
	if (!info)
		return -ENOMEM;
	dev_set_drvdata(&dev->dev, info);
	info->xbdev = dev;
	info->vtermno = xenbus_devid_to_vtermno(devid);
	info->intf = (void *)__get_free_page(GFP_KERNEL | __GFP_ZERO);
	if (!info->intf)
		goto error_nomem;

	ret = xencons_connect_backend(dev, info);
	if (ret < 0)
		goto error;
	spin_lock(&xencons_lock);
	list_add_tail(&info->list, &xenconsoles);
	spin_unlock(&xencons_lock);

	return 0;

 error_nomem:
	ret = -ENOMEM;
	xenbus_dev_fatal(dev, ret, "allocating device memory");
 error:
	xencons_disconnect_backend(info);
	xencons_free(info);
	return ret;
}

static int xencons_resume(struct xenbus_device *dev)
{
	struct xencons_info *info = dev_get_drvdata(&dev->dev);

	xencons_disconnect_backend(info);
	memset(info->intf, 0, PAGE_SIZE);
	return xencons_connect_backend(dev, info);
}

static void xencons_backend_changed(struct xenbus_device *dev,
				   enum xenbus_state backend_state)
{
	switch (backend_state) {
	case XenbusStateReconfiguring:
	case XenbusStateReconfigured:
	case XenbusStateInitialising:
	case XenbusStateInitialised:
	case XenbusStateUnknown:
		break;

	case XenbusStateInitWait:
		break;

	case XenbusStateConnected:
		xenbus_switch_state(dev, XenbusStateConnected);
		break;

	case XenbusStateClosed:
		if (dev->state == XenbusStateClosed)
			break;
		/* Missed the backend's CLOSING state -- fallthrough */
	case XenbusStateClosing:
		xenbus_frontend_closed(dev);
		break;
	}
}

static const struct xenbus_device_id xencons_ids[] = {
	{ "console" },
	{ "" }
};


static DEFINE_XENBUS_DRIVER(xencons, "xenconsole",
	.probe = xencons_probe,
	.remove = xencons_remove,
	.resume = xencons_resume,
	.otherend_changed = xencons_backend_changed,
);
#endif /* CONFIG_HVC_XEN_FRONTEND */

static int __init xen_hvc_init(void)
{
	int r;
	struct xencons_info *info;
	const struct hv_ops *ops;

	if (!xen_domain())
		return -ENODEV;

	if (xen_initial_domain()) {
		ops = &dom0_hvc_ops;
		r = xen_initial_domain_console_init();
		if (r < 0)
			return r;
		info = vtermno_to_xencons(HVC_COOKIE);
	} else {
		ops = &domU_hvc_ops;
		if (xen_hvm_domain())
			r = xen_hvm_console_init();
		else
			r = xen_pv_console_init();
		if (r < 0)
			return r;

		info = vtermno_to_xencons(HVC_COOKIE);
		info->irq = bind_evtchn_to_irq(info->evtchn);
	}
	if (info->irq < 0)
		info->irq = 0; /* NO_IRQ */
	else
		irq_set_noprobe(info->irq);

	info->hvc = hvc_alloc(HVC_COOKIE, info->irq, ops, 256);
	if (IS_ERR(info->hvc)) {
		r = PTR_ERR(info->hvc);
		spin_lock(&xencons_lock);
		list_del(&info->list);
		spin_unlock(&xencons_lock);
		if (info->irq)
			unbind_from_irqhandler(info->irq, NULL);
		kfree(info);
		return r;
	}

	r = 0;
#ifdef CONFIG_HVC_XEN_FRONTEND
	r = xenbus_register_frontend(&xencons_driver);
#endif
	return r;
}
device_initcall(xen_hvc_init);

static int xen_cons_init(void)
{
	const struct hv_ops *ops;

	if (!xen_domain())
		return 0;

	if (xen_initial_domain())
		ops = &dom0_hvc_ops;
	else {
		int r;
		ops = &domU_hvc_ops;

		if (xen_hvm_domain())
			r = xen_hvm_console_init();
		else
			r = xen_pv_console_init();
		if (r < 0)
			return r;
	}

	hvc_instantiate(HVC_COOKIE, 0, ops);
	return 0;
}
console_initcall(xen_cons_init);

#ifdef CONFIG_EARLY_PRINTK
static void xenboot_write_console(struct console *console, const char *string,
				  unsigned len)
{
	unsigned int linelen, off = 0;
	const char *pos;

	if (!xen_pv_domain())
		return;

	dom0_write_console(0, string, len);

	if (xen_initial_domain())
		return;

	domU_write_console(0, "(early) ", 8);
	while (off < len && NULL != (pos = strchr(string+off, '\n'))) {
		linelen = pos-string+off;
		if (off + linelen > len)
			break;
		domU_write_console(0, string+off, linelen);
		domU_write_console(0, "\r\n", 2);
		off += linelen + 1;
	}
	if (off < len)
		domU_write_console(0, string+off, len-off);
}

struct console xenboot_console = {
	.name		= "xenboot",
	.write		= xenboot_write_console,
	.flags		= CON_PRINTBUFFER | CON_BOOT | CON_ANYTIME,
	.index		= -1,
};
#endif	/* CONFIG_EARLY_PRINTK */

void xen_raw_console_write(const char *str)
{
	ssize_t len = strlen(str);
	int rc = 0;

	if (xen_domain()) {
		rc = dom0_write_console(0, str, len);
#ifdef CONFIG_X86
		if (rc == -ENOSYS && xen_hvm_domain())
			goto outb_print;

	} else if (xen_cpuid_base()) {
		int i;
outb_print:
		for (i = 0; i < len; i++)
			outb(str[i], 0xe9);
#endif
	}
}

void xen_raw_printk(const char *fmt, ...)
{
	static char buf[512];
	va_list ap;

	va_start(ap, fmt);
	vsnprintf(buf, sizeof(buf), fmt, ap);
	va_end(ap);

	xen_raw_console_write(buf);
}
Commit	Line	Data
b536b4b9 JF	1	/*
	2	* xen console driver interface to hvc_console.c
	3	*
	4	* (c) 2007 Gerd Hoffmann <kraxel@suse.de>
	5	*
	6	* This program is free software; you can redistribute it and/or modify
	7	* it under the terms of the GNU General Public License as published by
	8	* the Free Software Foundation; either version 2 of the License, or
	9	* (at your option) any later version.
	10	*
	11	* This program is distributed in the hope that it will be useful,
	12	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	13	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	14	* GNU General Public License for more details.
	15	*
	16	* You should have received a copy of the GNU General Public License
	17	* along with this program; if not, write to the Free Software
	18	* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
	19	*/
	20
	21	#include <linux/console.h>
	22	#include <linux/delay.h>
	23	#include <linux/err.h>
4d9310e3	24	#include <linux/irq.h>
b536b4b9 JF	25	#include <linux/init.h>
b536b4b9 JF	26	#include <linux/types.h>
02e19f9c	27	#include <linux/list.h>
b536b4b9	28
eb5ef071	29	#include <asm/io.h>
b536b4b9	30	#include <asm/xen/hypervisor.h>
1ccbf534 JF	31
1ccbf534 JF	32	#include <xen/xen.h>
eb5ef071 SS	33	#include <xen/interface/xen.h>
eb5ef071 SS	34	#include <xen/hvm.h>
02e19f9c	35	#include <xen/grant_table.h>
b536b4b9 JF	36	#include <xen/page.h>
	37	#include <xen/events.h>
	38	#include <xen/interface/io/console.h>
4d9310e3	39	#include <xen/interface/sched.h>
b536b4b9	40	#include <xen/hvc-console.h>
02e19f9c	41	#include <xen/xenbus.h>
b536b4b9 JF	42
	43	#include "hvc_console.h"
	44
	45	#define HVC_COOKIE 0x58656e /* "Xen" in hex */
	46
02e19f9c SS	47	struct xencons_info {
	48	struct list_head list;
	49	struct xenbus_device *xbdev;
	50	struct xencons_interface *intf;
	51	unsigned int evtchn;
	52	struct hvc_struct *hvc;
	53	int irq;
	54	int vtermno;
	55	grant_ref_t gntref;
	56	};
	57
	58	static LIST_HEAD(xenconsoles);
	59	static DEFINE_SPINLOCK(xencons_lock);
b536b4b9 JF	60
	61	/* ------------------------------------------------------------------ */
	62
02e19f9c SS	63	static struct xencons_info *vtermno_to_xencons(int vtermno)
	64	{
	65	struct xencons_info entry, n, *ret = NULL;
	66
	67	if (list_empty(&xenconsoles))
	68	return NULL;
	69
	70	list_for_each_entry_safe(entry, n, &xenconsoles, list) {
	71	if (entry->vtermno == vtermno) {
	72	ret = entry;
	73	break;
	74	}
	75	}
6b9b732d	76
02e19f9c SS	77	return ret;
	78	}
	79
	80	static inline int xenbus_devid_to_vtermno(int devid)
b536b4b9	81	{
02e19f9c	82	return devid + HVC_COOKIE;
b536b4b9 JF	83	}
b536b4b9 JF	84
02e19f9c	85	static inline void notify_daemon(struct xencons_info *cons)
b536b4b9 JF	86	{
b536b4b9 JF	87	/* Use evtchn: this is called early, before irq is set up. */
02e19f9c	88	notify_remote_via_evtchn(cons->evtchn);
b536b4b9 JF	89	}
b536b4b9 JF	90
02e19f9c SS	91	static int __write_console(struct xencons_info *xencons,
02e19f9c SS	92	const char *data, int len)
b536b4b9	93	{
b536b4b9	94	XENCONS_RING_IDX cons, prod;
02e19f9c	95	struct xencons_interface *intf = xencons->intf;
b536b4b9 JF	96	int sent = 0;
	97
	98	cons = intf->out_cons;
	99	prod = intf->out_prod;
	100	mb(); /* update queue values before going on */
	101	BUG_ON((prod - cons) > sizeof(intf->out));
	102
	103	while ((sent < len) && ((prod - cons) < sizeof(intf->out)))
	104	intf->out[MASK_XENCONS_IDX(prod++, intf->out)] = data[sent++];
	105
	106	wmb(); /* write ring before updating pointer */
	107	intf->out_prod = prod;
	108
403a85ff	109	if (sent)
02e19f9c	110	notify_daemon(xencons);
b536b4b9 JF	111	return sent;
	112	}
	113
4fe7d5a7	114	static int domU_write_console(uint32_t vtermno, const char *data, int len)
7825cf10 JF	115	{
7825cf10 JF	116	int ret = len;
02e19f9c SS	117	struct xencons_info *cons = vtermno_to_xencons(vtermno);
	118	if (cons == NULL)
	119	return -EINVAL;
7825cf10 JF	120
	121	/*
	122	* Make sure the whole buffer is emitted, polling if
	123	* necessary. We don't ever want to rely on the hvc daemon
	124	* because the most interesting console output is when the
	125	* kernel is crippled.
	126	*/
	127	while (len) {
02e19f9c	128	int sent = __write_console(cons, data, len);
7825cf10 JF	129
	130	data += sent;
	131	len -= sent;
	132
	133	if (unlikely(len))
	134	HYPERVISOR_sched_op(SCHEDOP_yield, NULL);
	135	}
	136
	137	return ret;
	138	}
	139
4fe7d5a7	140	static int domU_read_console(uint32_t vtermno, char *buf, int len)
b536b4b9	141	{
02e19f9c	142	struct xencons_interface *intf;
b536b4b9 JF	143	XENCONS_RING_IDX cons, prod;
b536b4b9 JF	144	int recv = 0;
02e19f9c SS	145	struct xencons_info *xencons = vtermno_to_xencons(vtermno);
	146	if (xencons == NULL)
	147	return -EINVAL;
	148	intf = xencons->intf;
b536b4b9 JF	149
	150	cons = intf->in_cons;
	151	prod = intf->in_prod;
	152	mb(); /* get pointers before reading ring */
	153	BUG_ON((prod - cons) > sizeof(intf->in));
	154
	155	while (cons != prod && recv < len)
	156	buf[recv++] = intf->in[MASK_XENCONS_IDX(cons++, intf->in)];
	157
	158	mb(); /* read ring before consuming */
	159	intf->in_cons = cons;
	160
02e19f9c	161	notify_daemon(xencons);
b536b4b9 JF	162	return recv;
	163	}
	164
4fe7d5a7 JF	165	static struct hv_ops domU_hvc_ops = {
	166	.get_chars = domU_read_console,
	167	.put_chars = domU_write_console,
611e097d CB	168	.notifier_add = notifier_add_irq,
611e097d CB	169	.notifier_del = notifier_del_irq,
fc362e2e	170	.notifier_hangup = notifier_hangup_irq,
b536b4b9 JF	171	};
b536b4b9 JF	172
4fe7d5a7 JF	173	static int dom0_read_console(uint32_t vtermno, char *buf, int len)
	174	{
	175	return HYPERVISOR_console_io(CONSOLEIO_read, len, buf);
	176	}
	177
	178	/*
	179	* Either for a dom0 to write to the system console, or a domU with a
	180	* debug version of Xen
	181	*/
	182	static int dom0_write_console(uint32_t vtermno, const char *str, int len)
	183	{
	184	int rc = HYPERVISOR_console_io(CONSOLEIO_write, len, (char *)str);
	185	if (rc < 0)
04b772d2	186	return rc;
4fe7d5a7 JF	187
	188	return len;
	189	}
	190
	191	static struct hv_ops dom0_hvc_ops = {
	192	.get_chars = dom0_read_console,
	193	.put_chars = dom0_write_console,
	194	.notifier_add = notifier_add_irq,
	195	.notifier_del = notifier_del_irq,
	196	.notifier_hangup = notifier_hangup_irq,
	197	};
	198
eb5ef071 SS	199	static int xen_hvm_console_init(void)
	200	{
	201	int r;
	202	uint64_t v = 0;
	203	unsigned long mfn;
02e19f9c	204	struct xencons_info *info;
eb5ef071 SS	205
	206	if (!xen_hvm_domain())
	207	return -ENODEV;
	208
02e19f9c SS	209	info = vtermno_to_xencons(HVC_COOKIE);
02e19f9c SS	210	if (!info) {
2d1d3f3a	211	info = kzalloc(sizeof(struct xencons_info), GFP_KERNEL);
02e19f9c SS	212	if (!info)
02e19f9c SS	213	return -ENOMEM;
37a80bf5 KRW	214	} else if (info->intf != NULL) {
37a80bf5 KRW	215	/* already configured */
02e19f9c	216	return 0;
37a80bf5	217	}
5842f576 KRW	218	/*
	219	* If the toolstack (or the hypervisor) hasn't set these values, the
	220	* default value is 0. Even though mfn = 0 and evtchn = 0 are
	221	* theoretically correct values, in practice they never are and they
	222	* mean that a legacy toolstack hasn't initialized the pv console correctly.
	223	*/
eb5ef071	224	r = hvm_get_parameter(HVM_PARAM_CONSOLE_EVTCHN, &v);
5842f576	225	if (r < 0 \|\| v == 0)
2e5ad6b9	226	goto err;
02e19f9c	227	info->evtchn = v;
a32c88b9 KRW	228	v = 0;
a32c88b9 KRW	229	r = hvm_get_parameter(HVM_PARAM_CONSOLE_PFN, &v);
5842f576	230	if (r < 0 \|\| v == 0)
2e5ad6b9	231	goto err;
eb5ef071	232	mfn = v;
3216dceb	233	info->intf = xen_remap(mfn << PAGE_SHIFT, PAGE_SIZE);
2e5ad6b9 KRW	234	if (info->intf == NULL)
2e5ad6b9 KRW	235	goto err;
02e19f9c SS	236	info->vtermno = HVC_COOKIE;
	237
	238	spin_lock(&xencons_lock);
	239	list_add_tail(&info->list, &xenconsoles);
	240	spin_unlock(&xencons_lock);
	241
	242	return 0;
2e5ad6b9 KRW	243	err:
	244	kfree(info);
	245	return -ENODEV;
02e19f9c SS	246	}
	247
	248	static int xen_pv_console_init(void)
	249	{
	250	struct xencons_info *info;
	251
	252	if (!xen_pv_domain())
	253	return -ENODEV;
	254
	255	if (!xen_start_info->console.domU.evtchn)
	256	return -ENODEV;
	257
	258	info = vtermno_to_xencons(HVC_COOKIE);
	259	if (!info) {
2d1d3f3a	260	info = kzalloc(sizeof(struct xencons_info), GFP_KERNEL);
02e19f9c SS	261	if (!info)
02e19f9c SS	262	return -ENOMEM;
37a80bf5 KRW	263	} else if (info->intf != NULL) {
37a80bf5 KRW	264	/* already configured */
02e19f9c	265	return 0;
37a80bf5	266	}
02e19f9c SS	267	info->evtchn = xen_start_info->console.domU.evtchn;
	268	info->intf = mfn_to_virt(xen_start_info->console.domU.mfn);
	269	info->vtermno = HVC_COOKIE;
	270
	271	spin_lock(&xencons_lock);
	272	list_add_tail(&info->list, &xenconsoles);
	273	spin_unlock(&xencons_lock);
	274
	275	return 0;
	276	}
	277
	278	static int xen_initial_domain_console_init(void)
	279	{
	280	struct xencons_info *info;
	281
	282	if (!xen_initial_domain())
	283	return -ENODEV;
	284
	285	info = vtermno_to_xencons(HVC_COOKIE);
	286	if (!info) {
2d1d3f3a	287	info = kzalloc(sizeof(struct xencons_info), GFP_KERNEL);
02e19f9c SS	288	if (!info)
	289	return -ENOMEM;
	290	}
	291
	292	info->irq = bind_virq_to_irq(VIRQ_CONSOLE, 0);
	293	info->vtermno = HVC_COOKIE;
	294
	295	spin_lock(&xencons_lock);
	296	list_add_tail(&info->list, &xenconsoles);
	297	spin_unlock(&xencons_lock);
eb5ef071 SS	298
	299	return 0;
	300	}
	301
02e19f9c SS	302	void xen_console_resume(void)
	303	{
	304	struct xencons_info *info = vtermno_to_xencons(HVC_COOKIE);
	305	if (info != NULL && info->irq)
	306	rebind_evtchn_irq(info->evtchn, info->irq);
	307	}
	308
	309	static void xencons_disconnect_backend(struct xencons_info *info)
	310	{
	311	if (info->irq > 0)
	312	unbind_from_irqhandler(info->irq, NULL);
	313	info->irq = 0;
	314	if (info->evtchn > 0)
	315	xenbus_free_evtchn(info->xbdev, info->evtchn);
	316	info->evtchn = 0;
	317	if (info->gntref > 0)
	318	gnttab_free_grant_references(info->gntref);
	319	info->gntref = 0;
	320	if (info->hvc != NULL)
	321	hvc_remove(info->hvc);
	322	info->hvc = NULL;
	323	}
	324
	325	static void xencons_free(struct xencons_info *info)
	326	{
	327	free_page((unsigned long)info->intf);
	328	info->intf = NULL;
	329	info->vtermno = 0;
	330	kfree(info);
	331	}
	332
	333	static int xen_console_remove(struct xencons_info *info)
	334	{
	335	xencons_disconnect_backend(info);
	336	spin_lock(&xencons_lock);
	337	list_del(&info->list);
	338	spin_unlock(&xencons_lock);
	339	if (info->xbdev != NULL)
	340	xencons_free(info);
	341	else {
	342	if (xen_hvm_domain())
	343	iounmap(info->intf);
	344	kfree(info);
4fe7d5a7	345	}
02e19f9c SS	346	return 0;
02e19f9c SS	347	}
6b9b732d	348
cf8e019b SS	349	#ifdef CONFIG_HVC_XEN_FRONTEND
	350	static struct xenbus_driver xencons_driver;
	351
02e19f9c SS	352	static int xencons_remove(struct xenbus_device *dev)
	353	{
	354	return xen_console_remove(dev_get_drvdata(&dev->dev));
	355	}
b536b4b9	356
02e19f9c SS	357	static int xencons_connect_backend(struct xenbus_device *dev,
	358	struct xencons_info *info)
	359	{
	360	int ret, evtchn, devid, ref, irq;
	361	struct xenbus_transaction xbt;
	362	grant_ref_t gref_head;
	363	unsigned long mfn;
	364
	365	ret = xenbus_alloc_evtchn(dev, &evtchn);
	366	if (ret)
	367	return ret;
	368	info->evtchn = evtchn;
	369	irq = bind_evtchn_to_irq(evtchn);
	370	if (irq < 0)
	371	return irq;
	372	info->irq = irq;
	373	devid = dev->nodename[strlen(dev->nodename) - 1] - '0';
	374	info->hvc = hvc_alloc(xenbus_devid_to_vtermno(devid),
	375	irq, &domU_hvc_ops, 256);
	376	if (IS_ERR(info->hvc))
	377	return PTR_ERR(info->hvc);
	378	if (xen_pv_domain())
	379	mfn = virt_to_mfn(info->intf);
	380	else
	381	mfn = __pa(info->intf) >> PAGE_SHIFT;
	382	ret = gnttab_alloc_grant_references(1, &gref_head);
	383	if (ret < 0)
	384	return ret;
	385	info->gntref = gref_head;
	386	ref = gnttab_claim_grant_reference(&gref_head);
	387	if (ref < 0)
	388	return ref;
	389	gnttab_grant_foreign_access_ref(ref, info->xbdev->otherend_id,
	390	mfn, 0);
	391
	392	again:
	393	ret = xenbus_transaction_start(&xbt);
	394	if (ret) {
	395	xenbus_dev_fatal(dev, ret, "starting transaction");
	396	return ret;
	397	}
	398	ret = xenbus_printf(xbt, dev->nodename, "ring-ref", "%d", ref);
	399	if (ret)
	400	goto error_xenbus;
	401	ret = xenbus_printf(xbt, dev->nodename, "port", "%u",
	402	evtchn);
	403	if (ret)
	404	goto error_xenbus;
	405	ret = xenbus_printf(xbt, dev->nodename, "type", "ioemu");
	406	if (ret)
	407	goto error_xenbus;
	408	ret = xenbus_transaction_end(xbt, 0);
	409	if (ret) {
	410	if (ret == -EAGAIN)
	411	goto again;
	412	xenbus_dev_fatal(dev, ret, "completing transaction");
	413	return ret;
	414	}
6b9b732d	415
02e19f9c	416	xenbus_switch_state(dev, XenbusStateInitialised);
b536b4b9	417	return 0;
02e19f9c SS	418
	419	error_xenbus:
	420	xenbus_transaction_end(xbt, 1);
	421	xenbus_dev_fatal(dev, ret, "writing xenstore");
	422	return ret;
b536b4b9 JF	423	}
b536b4b9 JF	424
9671f099	425	static int xencons_probe(struct xenbus_device *dev,
02e19f9c	426	const struct xenbus_device_id *id)
6b9b732d	427	{
02e19f9c SS	428	int ret, devid;
	429	struct xencons_info *info;
	430
	431	devid = dev->nodename[strlen(dev->nodename) - 1] - '0';
	432	if (devid == 0)
	433	return -ENODEV;
	434
201a52be	435	info = kzalloc(sizeof(struct xencons_info), GFP_KERNEL);
02e19f9c	436	if (!info)
201a52be	437	return -ENOMEM;
02e19f9c SS	438	dev_set_drvdata(&dev->dev, info);
	439	info->xbdev = dev;
	440	info->vtermno = xenbus_devid_to_vtermno(devid);
	441	info->intf = (void *)__get_free_page(GFP_KERNEL \| __GFP_ZERO);
	442	if (!info->intf)
	443	goto error_nomem;
	444
	445	ret = xencons_connect_backend(dev, info);
	446	if (ret < 0)
	447	goto error;
	448	spin_lock(&xencons_lock);
	449	list_add_tail(&info->list, &xenconsoles);
	450	spin_unlock(&xencons_lock);
	451
	452	return 0;
	453
	454	error_nomem:
	455	ret = -ENOMEM;
	456	xenbus_dev_fatal(dev, ret, "allocating device memory");
	457	error:
	458	xencons_disconnect_backend(info);
	459	xencons_free(info);
	460	return ret;
	461	}
	462
	463	static int xencons_resume(struct xenbus_device *dev)
	464	{
	465	struct xencons_info *info = dev_get_drvdata(&dev->dev);
	466
	467	xencons_disconnect_backend(info);
	468	memset(info->intf, 0, PAGE_SIZE);
	469	return xencons_connect_backend(dev, info);
6b9b732d JF	470	}
6b9b732d JF	471
02e19f9c SS	472	static void xencons_backend_changed(struct xenbus_device *dev,
	473	enum xenbus_state backend_state)
	474	{
	475	switch (backend_state) {
	476	case XenbusStateReconfiguring:
	477	case XenbusStateReconfigured:
	478	case XenbusStateInitialising:
	479	case XenbusStateInitialised:
	480	case XenbusStateUnknown:
02e19f9c SS	481	break;
	482
	483	case XenbusStateInitWait:
	484	break;
	485
	486	case XenbusStateConnected:
	487	xenbus_switch_state(dev, XenbusStateConnected);
	488	break;
	489
9b6934a3 DV	490	case XenbusStateClosed:
	491	if (dev->state == XenbusStateClosed)
	492	break;
	493	/* Missed the backend's CLOSING state -- fallthrough */
02e19f9c SS	494	case XenbusStateClosing:
	495	xenbus_frontend_closed(dev);
	496	break;
	497	}
	498	}
	499
	500	static const struct xenbus_device_id xencons_ids[] = {
	501	{ "console" },
	502	{ "" }
	503	};
	504
	505
cf8e019b SS	506	static DEFINE_XENBUS_DRIVER(xencons, "xenconsole",
	507	.probe = xencons_probe,
	508	.remove = xencons_remove,
	509	.resume = xencons_resume,
	510	.otherend_changed = xencons_backend_changed,
	511	);
	512	#endif /* CONFIG_HVC_XEN_FRONTEND */
	513
	514	static int __init xen_hvc_init(void)
	515	{
	516	int r;
	517	struct xencons_info *info;
	518	const struct hv_ops *ops;
	519
	520	if (!xen_domain())
	521	return -ENODEV;
	522
	523	if (xen_initial_domain()) {
	524	ops = &dom0_hvc_ops;
	525	r = xen_initial_domain_console_init();
	526	if (r < 0)
	527	return r;
	528	info = vtermno_to_xencons(HVC_COOKIE);
	529	} else {
	530	ops = &domU_hvc_ops;
	531	if (xen_hvm_domain())
	532	r = xen_hvm_console_init();
	533	else
	534	r = xen_pv_console_init();
	535	if (r < 0)
	536	return r;
	537
	538	info = vtermno_to_xencons(HVC_COOKIE);
	539	info->irq = bind_evtchn_to_irq(info->evtchn);
	540	}
	541	if (info->irq < 0)
	542	info->irq = 0; /* NO_IRQ */
	543	else
	544	irq_set_noprobe(info->irq);
	545
	546	info->hvc = hvc_alloc(HVC_COOKIE, info->irq, ops, 256);
	547	if (IS_ERR(info->hvc)) {
	548	r = PTR_ERR(info->hvc);
	549	spin_lock(&xencons_lock);
	550	list_del(&info->list);
	551	spin_unlock(&xencons_lock);
	552	if (info->irq)
	553	unbind_from_irqhandler(info->irq, NULL);
	554	kfree(info);
	555	return r;
	556	}
	557
	558	r = 0;
	559	#ifdef CONFIG_HVC_XEN_FRONTEND
	560	r = xenbus_register_frontend(&xencons_driver);
	561	#endif
	562	return r;
	563	}
4fedd0bf	564	device_initcall(xen_hvc_init);
b536b4b9 JF	565
	566	static int xen_cons_init(void)
	567	{
eb5ef071	568	const struct hv_ops *ops;
4fe7d5a7	569
eb5ef071	570	if (!xen_domain())
b536b4b9 JF	571	return 0;
b536b4b9 JF	572
4fe7d5a7 JF	573	if (xen_initial_domain())
4fe7d5a7 JF	574	ops = &dom0_hvc_ops;
eb5ef071	575	else {
02e19f9c	576	int r;
4fe7d5a7 JF	577	ops = &domU_hvc_ops;
4fe7d5a7 JF	578
02e19f9c SS	579	if (xen_hvm_domain())
02e19f9c SS	580	r = xen_hvm_console_init();
eb5ef071	581	else
02e19f9c SS	582	r = xen_pv_console_init();
	583	if (r < 0)
	584	return r;
eb5ef071 SS	585	}
eb5ef071 SS	586
4fe7d5a7	587	hvc_instantiate(HVC_COOKIE, 0, ops);
b536b4b9 JF	588	return 0;
b536b4b9 JF	589	}
b536b4b9 JF	590	console_initcall(xen_cons_init);
b536b4b9 JF	591
0922abdc	592	#ifdef CONFIG_EARLY_PRINTK
b536b4b9 JF	593	static void xenboot_write_console(struct console console, const char string,
	594	unsigned len)
	595	{
	596	unsigned int linelen, off = 0;
	597	const char *pos;
	598
eb5ef071 SS	599	if (!xen_pv_domain())
	600	return;
	601
4fe7d5a7 JF	602	dom0_write_console(0, string, len);
	603
	604	if (xen_initial_domain())
	605	return;
0922abdc	606
4fe7d5a7	607	domU_write_console(0, "(early) ", 8);
b536b4b9 JF	608	while (off < len && NULL != (pos = strchr(string+off, '\n'))) {
	609	linelen = pos-string+off;
	610	if (off + linelen > len)
	611	break;
4fe7d5a7 JF	612	domU_write_console(0, string+off, linelen);
4fe7d5a7 JF	613	domU_write_console(0, "\r\n", 2);
b536b4b9 JF	614	off += linelen + 1;
	615	}
	616	if (off < len)
4fe7d5a7	617	domU_write_console(0, string+off, len-off);
b536b4b9 JF	618	}
	619
	620	struct console xenboot_console = {
	621	.name = "xenboot",
	622	.write = xenboot_write_console,
0922abdc	623	.flags = CON_PRINTBUFFER \| CON_BOOT \| CON_ANYTIME,
a9fbf4d5	624	.index = -1,
b536b4b9	625	};
0922abdc	626	#endif /* CONFIG_EARLY_PRINTK */
0acf10d8 JF	627
	628	void xen_raw_console_write(const char *str)
	629	{
04b772d2 KRW	630	ssize_t len = strlen(str);
	631	int rc = 0;
	632
	633	if (xen_domain()) {
	634	rc = dom0_write_console(0, str, len);
	635	#ifdef CONFIG_X86
	636	if (rc == -ENOSYS && xen_hvm_domain())
	637	goto outb_print;
	638
	639	} else if (xen_cpuid_base()) {
	640	int i;
	641	outb_print:
	642	for (i = 0; i < len; i++)
	643	outb(str[i], 0xe9);
	644	#endif
	645	}
0acf10d8 JF	646	}
	647
	648	void xen_raw_printk(const char *fmt, ...)
	649	{
	650	static char buf[512];
	651	va_list ap;
	652
	653	va_start(ap, fmt);
	654	vsnprintf(buf, sizeof(buf), fmt, ap);
	655	va_end(ap);
	656
	657	xen_raw_console_write(buf);
	658	}