[linux-2.6-block.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 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_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 struct xenbus_driver xencons_driver = {
	.name = "xenconsole",
	.ids = xencons_ids,
	.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	349	#ifdef CONFIG_HVC_XEN_FRONTEND
02e19f9c SS	350	static int xencons_remove(struct xenbus_device *dev)
	351	{
	352	return xen_console_remove(dev_get_drvdata(&dev->dev));
	353	}
b536b4b9	354
02e19f9c SS	355	static int xencons_connect_backend(struct xenbus_device *dev,
	356	struct xencons_info *info)
	357	{
	358	int ret, evtchn, devid, ref, irq;
	359	struct xenbus_transaction xbt;
	360	grant_ref_t gref_head;
	361	unsigned long mfn;
	362
	363	ret = xenbus_alloc_evtchn(dev, &evtchn);
	364	if (ret)
	365	return ret;
	366	info->evtchn = evtchn;
	367	irq = bind_evtchn_to_irq(evtchn);
	368	if (irq < 0)
	369	return irq;
	370	info->irq = irq;
	371	devid = dev->nodename[strlen(dev->nodename) - 1] - '0';
	372	info->hvc = hvc_alloc(xenbus_devid_to_vtermno(devid),
	373	irq, &domU_hvc_ops, 256);
	374	if (IS_ERR(info->hvc))
	375	return PTR_ERR(info->hvc);
	376	if (xen_pv_domain())
	377	mfn = virt_to_mfn(info->intf);
	378	else
	379	mfn = __pa(info->intf) >> PAGE_SHIFT;
	380	ret = gnttab_alloc_grant_references(1, &gref_head);
	381	if (ret < 0)
	382	return ret;
	383	info->gntref = gref_head;
	384	ref = gnttab_claim_grant_reference(&gref_head);
	385	if (ref < 0)
	386	return ref;
	387	gnttab_grant_foreign_access_ref(ref, info->xbdev->otherend_id,
	388	mfn, 0);
	389
	390	again:
	391	ret = xenbus_transaction_start(&xbt);
	392	if (ret) {
	393	xenbus_dev_fatal(dev, ret, "starting transaction");
	394	return ret;
	395	}
	396	ret = xenbus_printf(xbt, dev->nodename, "ring-ref", "%d", ref);
	397	if (ret)
	398	goto error_xenbus;
	399	ret = xenbus_printf(xbt, dev->nodename, "port", "%u",
	400	evtchn);
02e19f9c SS	401	if (ret)
	402	goto error_xenbus;
	403	ret = xenbus_transaction_end(xbt, 0);
	404	if (ret) {
	405	if (ret == -EAGAIN)
	406	goto again;
	407	xenbus_dev_fatal(dev, ret, "completing transaction");
	408	return ret;
	409	}
6b9b732d	410
02e19f9c	411	xenbus_switch_state(dev, XenbusStateInitialised);
b536b4b9	412	return 0;
02e19f9c SS	413
	414	error_xenbus:
	415	xenbus_transaction_end(xbt, 1);
	416	xenbus_dev_fatal(dev, ret, "writing xenstore");
	417	return ret;
b536b4b9 JF	418	}
b536b4b9 JF	419
9671f099	420	static int xencons_probe(struct xenbus_device *dev,
02e19f9c	421	const struct xenbus_device_id *id)
6b9b732d	422	{
02e19f9c SS	423	int ret, devid;
	424	struct xencons_info *info;
	425
	426	devid = dev->nodename[strlen(dev->nodename) - 1] - '0';
	427	if (devid == 0)
	428	return -ENODEV;
	429
201a52be	430	info = kzalloc(sizeof(struct xencons_info), GFP_KERNEL);
02e19f9c	431	if (!info)
201a52be	432	return -ENOMEM;
02e19f9c SS	433	dev_set_drvdata(&dev->dev, info);
	434	info->xbdev = dev;
	435	info->vtermno = xenbus_devid_to_vtermno(devid);
	436	info->intf = (void *)__get_free_page(GFP_KERNEL \| __GFP_ZERO);
	437	if (!info->intf)
	438	goto error_nomem;
	439
	440	ret = xencons_connect_backend(dev, info);
	441	if (ret < 0)
	442	goto error;
	443	spin_lock(&xencons_lock);
	444	list_add_tail(&info->list, &xenconsoles);
	445	spin_unlock(&xencons_lock);
	446
	447	return 0;
	448
	449	error_nomem:
	450	ret = -ENOMEM;
	451	xenbus_dev_fatal(dev, ret, "allocating device memory");
	452	error:
	453	xencons_disconnect_backend(info);
	454	xencons_free(info);
	455	return ret;
	456	}
	457
	458	static int xencons_resume(struct xenbus_device *dev)
	459	{
	460	struct xencons_info *info = dev_get_drvdata(&dev->dev);
	461
	462	xencons_disconnect_backend(info);
	463	memset(info->intf, 0, PAGE_SIZE);
	464	return xencons_connect_backend(dev, info);
6b9b732d JF	465	}
6b9b732d JF	466
02e19f9c SS	467	static void xencons_backend_changed(struct xenbus_device *dev,
	468	enum xenbus_state backend_state)
	469	{
	470	switch (backend_state) {
	471	case XenbusStateReconfiguring:
	472	case XenbusStateReconfigured:
	473	case XenbusStateInitialising:
	474	case XenbusStateInitialised:
	475	case XenbusStateUnknown:
02e19f9c SS	476	break;
	477
	478	case XenbusStateInitWait:
	479	break;
	480
	481	case XenbusStateConnected:
	482	xenbus_switch_state(dev, XenbusStateConnected);
	483	break;
	484
9b6934a3 DV	485	case XenbusStateClosed:
	486	if (dev->state == XenbusStateClosed)
	487	break;
	488	/* Missed the backend's CLOSING state -- fallthrough */
02e19f9c SS	489	case XenbusStateClosing:
	490	xenbus_frontend_closed(dev);
	491	break;
	492	}
	493	}
	494
	495	static const struct xenbus_device_id xencons_ids[] = {
	496	{ "console" },
	497	{ "" }
	498	};
	499
95afae48 DV	500	static struct xenbus_driver xencons_driver = {
	501	.name = "xenconsole",
	502	.ids = xencons_ids,
cf8e019b SS	503	.probe = xencons_probe,
	504	.remove = xencons_remove,
	505	.resume = xencons_resume,
	506	.otherend_changed = xencons_backend_changed,
95afae48	507	};
cf8e019b SS	508	#endif /* CONFIG_HVC_XEN_FRONTEND */
	509
	510	static int __init xen_hvc_init(void)
	511	{
	512	int r;
	513	struct xencons_info *info;
	514	const struct hv_ops *ops;
	515
	516	if (!xen_domain())
	517	return -ENODEV;
	518
	519	if (xen_initial_domain()) {
	520	ops = &dom0_hvc_ops;
	521	r = xen_initial_domain_console_init();
	522	if (r < 0)
	523	return r;
	524	info = vtermno_to_xencons(HVC_COOKIE);
	525	} else {
	526	ops = &domU_hvc_ops;
	527	if (xen_hvm_domain())
	528	r = xen_hvm_console_init();
	529	else
	530	r = xen_pv_console_init();
	531	if (r < 0)
	532	return r;
	533
	534	info = vtermno_to_xencons(HVC_COOKIE);
	535	info->irq = bind_evtchn_to_irq(info->evtchn);
	536	}
	537	if (info->irq < 0)
	538	info->irq = 0; /* NO_IRQ */
	539	else
	540	irq_set_noprobe(info->irq);
	541
	542	info->hvc = hvc_alloc(HVC_COOKIE, info->irq, ops, 256);
	543	if (IS_ERR(info->hvc)) {
	544	r = PTR_ERR(info->hvc);
	545	spin_lock(&xencons_lock);
	546	list_del(&info->list);
	547	spin_unlock(&xencons_lock);
	548	if (info->irq)
	549	unbind_from_irqhandler(info->irq, NULL);
	550	kfree(info);
	551	return r;
	552	}
	553
	554	r = 0;
	555	#ifdef CONFIG_HVC_XEN_FRONTEND
	556	r = xenbus_register_frontend(&xencons_driver);
	557	#endif
	558	return r;
	559	}
4fedd0bf	560	device_initcall(xen_hvc_init);
b536b4b9 JF	561
	562	static int xen_cons_init(void)
	563	{
eb5ef071	564	const struct hv_ops *ops;
4fe7d5a7	565
eb5ef071	566	if (!xen_domain())
b536b4b9 JF	567	return 0;
b536b4b9 JF	568
4fe7d5a7 JF	569	if (xen_initial_domain())
4fe7d5a7 JF	570	ops = &dom0_hvc_ops;
eb5ef071	571	else {
02e19f9c	572	int r;
4fe7d5a7 JF	573	ops = &domU_hvc_ops;
4fe7d5a7 JF	574
02e19f9c SS	575	if (xen_hvm_domain())
02e19f9c SS	576	r = xen_hvm_console_init();
eb5ef071	577	else
02e19f9c SS	578	r = xen_pv_console_init();
	579	if (r < 0)
	580	return r;
eb5ef071 SS	581	}
eb5ef071 SS	582
4fe7d5a7	583	hvc_instantiate(HVC_COOKIE, 0, ops);
b536b4b9 JF	584	return 0;
b536b4b9 JF	585	}
b536b4b9 JF	586	console_initcall(xen_cons_init);
b536b4b9 JF	587
0922abdc	588	#ifdef CONFIG_EARLY_PRINTK
b536b4b9 JF	589	static void xenboot_write_console(struct console console, const char string,
	590	unsigned len)
	591	{
	592	unsigned int linelen, off = 0;
	593	const char *pos;
	594
eb5ef071 SS	595	if (!xen_pv_domain())
	596	return;
	597
4fe7d5a7 JF	598	dom0_write_console(0, string, len);
	599
	600	if (xen_initial_domain())
	601	return;
0922abdc	602
4fe7d5a7	603	domU_write_console(0, "(early) ", 8);
b536b4b9 JF	604	while (off < len && NULL != (pos = strchr(string+off, '\n'))) {
	605	linelen = pos-string+off;
	606	if (off + linelen > len)
	607	break;
4fe7d5a7 JF	608	domU_write_console(0, string+off, linelen);
4fe7d5a7 JF	609	domU_write_console(0, "\r\n", 2);
b536b4b9 JF	610	off += linelen + 1;
	611	}
	612	if (off < len)
4fe7d5a7	613	domU_write_console(0, string+off, len-off);
b536b4b9 JF	614	}
	615
	616	struct console xenboot_console = {
	617	.name = "xenboot",
	618	.write = xenboot_write_console,
0922abdc	619	.flags = CON_PRINTBUFFER \| CON_BOOT \| CON_ANYTIME,
a9fbf4d5	620	.index = -1,
b536b4b9	621	};
0922abdc	622	#endif /* CONFIG_EARLY_PRINTK */
0acf10d8 JF	623
	624	void xen_raw_console_write(const char *str)
	625	{
04b772d2 KRW	626	ssize_t len = strlen(str);
	627	int rc = 0;
	628
	629	if (xen_domain()) {
	630	rc = dom0_write_console(0, str, len);
	631	#ifdef CONFIG_X86
	632	if (rc == -ENOSYS && xen_hvm_domain())
	633	goto outb_print;
	634
	635	} else if (xen_cpuid_base()) {
	636	int i;
	637	outb_print:
	638	for (i = 0; i < len; i++)
	639	outb(str[i], 0xe9);
	640	#endif
	641	}
0acf10d8 JF	642	}
	643
	644	void xen_raw_printk(const char *fmt, ...)
	645	{
	646	static char buf[512];
	647	va_list ap;
	648
	649	va_start(ap, fmt);
	650	vsnprintf(buf, sizeof(buf), fmt, ap);
	651	va_end(ap);
	652
	653	xen_raw_console_write(buf);
	654	}