summaryrefslogtreecommitdiff
path: root/drivers/tty/hvc/hvc_xen.c
diff options
context:
space:
mode:
Diffstat (limited to 'drivers/tty/hvc/hvc_xen.c')
-rw-r--r--drivers/tty/hvc/hvc_xen.c345
1 files changed, 230 insertions, 115 deletions
diff --git a/drivers/tty/hvc/hvc_xen.c b/drivers/tty/hvc/hvc_xen.c
index 682210d778bd..388a71afd6ef 100644
--- a/drivers/tty/hvc/hvc_xen.c
+++ b/drivers/tty/hvc/hvc_xen.c
@@ -1,21 +1,8 @@
+// SPDX-License-Identifier: GPL-2.0+
/*
* 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>
@@ -25,6 +12,7 @@
#include <linux/init.h>
#include <linux/types.h>
#include <linux/list.h>
+#include <linux/serial_core.h>
#include <asm/io.h>
#include <asm/xen/hypervisor.h>
@@ -49,10 +37,13 @@ struct xencons_info {
struct xenbus_device *xbdev;
struct xencons_interface *intf;
unsigned int evtchn;
+ XENCONS_RING_IDX out_cons;
+ unsigned int out_cons_same;
struct hvc_struct *hvc;
int irq;
int vtermno;
grant_ref_t gntref;
+ spinlock_t ring_lock;
};
static LIST_HEAD(xenconsoles);
@@ -62,17 +53,22 @@ static DEFINE_SPINLOCK(xencons_lock);
static struct xencons_info *vtermno_to_xencons(int vtermno)
{
- struct xencons_info *entry, *n, *ret = NULL;
+ struct xencons_info *entry, *ret = NULL;
+ unsigned long flags;
- if (list_empty(&xenconsoles))
- return NULL;
+ spin_lock_irqsave(&xencons_lock, flags);
+ if (list_empty(&xenconsoles)) {
+ spin_unlock_irqrestore(&xencons_lock, flags);
+ return NULL;
+ }
- list_for_each_entry_safe(entry, n, &xenconsoles, list) {
+ list_for_each_entry(entry, &xenconsoles, list) {
if (entry->vtermno == vtermno) {
ret = entry;
break;
}
}
+ spin_unlock_irqrestore(&xencons_lock, flags);
return ret;
}
@@ -88,33 +84,42 @@ static inline void notify_daemon(struct xencons_info *cons)
notify_remote_via_evtchn(cons->evtchn);
}
-static int __write_console(struct xencons_info *xencons,
- const char *data, int len)
+static ssize_t __write_console(struct xencons_info *xencons,
+ const u8 *data, size_t len)
{
XENCONS_RING_IDX cons, prod;
struct xencons_interface *intf = xencons->intf;
- int sent = 0;
+ unsigned long flags;
+ size_t sent = 0;
+ spin_lock_irqsave(&xencons->ring_lock, flags);
cons = intf->out_cons;
prod = intf->out_prod;
mb(); /* update queue values before going on */
- BUG_ON((prod - cons) > sizeof(intf->out));
+
+ if ((prod - cons) > sizeof(intf->out)) {
+ spin_unlock_irqrestore(&xencons->ring_lock, flags);
+ pr_err_once("xencons: Illegal ring page indices");
+ return -EINVAL;
+ }
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;
+ spin_unlock_irqrestore(&xencons->ring_lock, flags);
if (sent)
notify_daemon(xencons);
return sent;
}
-static int domU_write_console(uint32_t vtermno, const char *data, int len)
+static ssize_t domU_write_console(uint32_t vtermno, const u8 *data, size_t len)
{
- int ret = len;
struct xencons_info *cons = vtermno_to_xencons(vtermno);
+ size_t ret = len;
+
if (cons == NULL)
return -EINVAL;
@@ -125,8 +130,11 @@ static int domU_write_console(uint32_t vtermno, const char *data, int len)
* kernel is crippled.
*/
while (len) {
- int sent = __write_console(cons, data, len);
-
+ ssize_t sent = __write_console(cons, data, len);
+
+ if (sent < 0)
+ return sent;
+
data += sent;
len -= sent;
@@ -137,20 +145,29 @@ static int domU_write_console(uint32_t vtermno, const char *data, int len)
return ret;
}
-static int domU_read_console(uint32_t vtermno, char *buf, int len)
+static ssize_t domU_read_console(uint32_t vtermno, u8 *buf, size_t len)
{
struct xencons_interface *intf;
XENCONS_RING_IDX cons, prod;
- int recv = 0;
struct xencons_info *xencons = vtermno_to_xencons(vtermno);
+ unsigned int eoiflag = 0;
+ unsigned long flags;
+ size_t recv = 0;
+
if (xencons == NULL)
return -EINVAL;
intf = xencons->intf;
+ spin_lock_irqsave(&xencons->ring_lock, flags);
cons = intf->in_cons;
prod = intf->in_prod;
mb(); /* get pointers before reading ring */
- BUG_ON((prod - cons) > sizeof(intf->in));
+
+ if ((prod - cons) > sizeof(intf->in)) {
+ spin_unlock_irqrestore(&xencons->ring_lock, flags);
+ pr_err_once("xencons: Illegal ring page indices");
+ return -EINVAL;
+ }
while (cons != prod && recv < len)
buf[recv++] = intf->in[MASK_XENCONS_IDX(cons++, intf->in)];
@@ -158,11 +175,34 @@ static int domU_read_console(uint32_t vtermno, char *buf, int len)
mb(); /* read ring before consuming */
intf->in_cons = cons;
- notify_daemon(xencons);
+ /*
+ * When to mark interrupt having been spurious:
+ * - there was no new data to be read, and
+ * - the backend did not consume some output bytes, and
+ * - the previous round with no read data didn't see consumed bytes
+ * (we might have a race with an interrupt being in flight while
+ * updating xencons->out_cons, so account for that by allowing one
+ * round without any visible reason)
+ */
+ if (intf->out_cons != xencons->out_cons) {
+ xencons->out_cons = intf->out_cons;
+ xencons->out_cons_same = 0;
+ }
+ if (!recv && xencons->out_cons_same++ > 1) {
+ eoiflag = XEN_EOI_FLAG_SPURIOUS;
+ }
+ spin_unlock_irqrestore(&xencons->ring_lock, flags);
+
+ if (recv) {
+ notify_daemon(xencons);
+ }
+
+ xen_irq_lateeoi(xencons->irq, eoiflag);
+
return recv;
}
-static struct hv_ops domU_hvc_ops = {
+static const struct hv_ops domU_hvc_ops = {
.get_chars = domU_read_console,
.put_chars = domU_write_console,
.notifier_add = notifier_add_irq,
@@ -170,7 +210,7 @@ static struct hv_ops domU_hvc_ops = {
.notifier_hangup = notifier_hangup_irq,
};
-static int dom0_read_console(uint32_t vtermno, char *buf, int len)
+static ssize_t dom0_read_console(uint32_t vtermno, u8 *buf, size_t len)
{
return HYPERVISOR_console_io(CONSOLEIO_read, len, buf);
}
@@ -179,16 +219,16 @@ static int dom0_read_console(uint32_t vtermno, char *buf, int len)
* 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)
+static ssize_t dom0_write_console(uint32_t vtermno, const u8 *str, size_t len)
{
- int rc = HYPERVISOR_console_io(CONSOLEIO_write, len, (char *)str);
+ int rc = HYPERVISOR_console_io(CONSOLEIO_write, len, (u8 *)str);
if (rc < 0)
- return 0;
+ return rc;
return len;
}
-static struct hv_ops dom0_hvc_ops = {
+static const struct hv_ops dom0_hvc_ops = {
.get_chars = dom0_read_console,
.put_chars = dom0_write_console,
.notifier_add = notifier_add_irq,
@@ -200,7 +240,7 @@ static int xen_hvm_console_init(void)
{
int r;
uint64_t v = 0;
- unsigned long mfn;
+ unsigned long gfn, flags;
struct xencons_info *info;
if (!xen_hvm_domain())
@@ -208,16 +248,17 @@ static int xen_hvm_console_init(void)
info = vtermno_to_xencons(HVC_COOKIE);
if (!info) {
- info = kzalloc(sizeof(struct xencons_info), GFP_KERNEL | __GFP_ZERO);
+ info = kzalloc(sizeof(struct xencons_info), GFP_KERNEL);
if (!info)
return -ENOMEM;
+ spin_lock_init(&info->ring_lock);
} 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
+ * default value is 0. Even though gfn = 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.
*/
@@ -229,15 +270,15 @@ static int xen_hvm_console_init(void)
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);
+ gfn = v;
+ info->intf = memremap(gfn << XEN_PAGE_SHIFT, XEN_PAGE_SIZE, MEMREMAP_WB);
if (info->intf == NULL)
goto err;
info->vtermno = HVC_COOKIE;
- spin_lock(&xencons_lock);
+ spin_lock_irqsave(&xencons_lock, flags);
list_add_tail(&info->list, &xenconsoles);
- spin_unlock(&xencons_lock);
+ spin_unlock_irqrestore(&xencons_lock, flags);
return 0;
err:
@@ -245,9 +286,23 @@ err:
return -ENODEV;
}
+static int xencons_info_pv_init(struct xencons_info *info, int vtermno)
+{
+ spin_lock_init(&info->ring_lock);
+ info->evtchn = xen_start_info->console.domU.evtchn;
+ /* GFN == MFN for PV guest */
+ info->intf = gfn_to_virt(xen_start_info->console.domU.mfn);
+ info->vtermno = vtermno;
+
+ list_add_tail(&info->list, &xenconsoles);
+
+ return 0;
+}
+
static int xen_pv_console_init(void)
{
struct xencons_info *info;
+ unsigned long flags;
if (!xen_pv_domain())
return -ENODEV;
@@ -257,20 +312,16 @@ static int xen_pv_console_init(void)
info = vtermno_to_xencons(HVC_COOKIE);
if (!info) {
- info = kzalloc(sizeof(struct xencons_info), GFP_KERNEL | __GFP_ZERO);
+ 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);
+ spin_lock_irqsave(&xencons_lock, flags);
+ xencons_info_pv_init(info, HVC_COOKIE);
+ spin_unlock_irqrestore(&xencons_lock, flags);
return 0;
}
@@ -278,48 +329,70 @@ static int xen_pv_console_init(void)
static int xen_initial_domain_console_init(void)
{
struct xencons_info *info;
+ unsigned long flags;
if (!xen_initial_domain())
return -ENODEV;
info = vtermno_to_xencons(HVC_COOKIE);
if (!info) {
- info = kzalloc(sizeof(struct xencons_info), GFP_KERNEL | __GFP_ZERO);
+ info = kzalloc(sizeof(struct xencons_info), GFP_KERNEL);
if (!info)
return -ENOMEM;
+ spin_lock_init(&info->ring_lock);
}
- info->irq = bind_virq_to_irq(VIRQ_CONSOLE, 0);
+ info->irq = bind_virq_to_irq(VIRQ_CONSOLE, 0, false);
info->vtermno = HVC_COOKIE;
- spin_lock(&xencons_lock);
+ spin_lock_irqsave(&xencons_lock, flags);
list_add_tail(&info->list, &xenconsoles);
- spin_unlock(&xencons_lock);
+ spin_unlock_irqrestore(&xencons_lock, flags);
return 0;
}
+static void xen_console_update_evtchn(struct xencons_info *info)
+{
+ if (xen_hvm_domain()) {
+ uint64_t v = 0;
+ int err;
+
+ err = hvm_get_parameter(HVM_PARAM_CONSOLE_EVTCHN, &v);
+ if (!err && v)
+ info->evtchn = v;
+ } else
+ info->evtchn = xen_start_info->console.domU.evtchn;
+}
+
void xen_console_resume(void)
{
struct xencons_info *info = vtermno_to_xencons(HVC_COOKIE);
- if (info != NULL && info->irq)
+ if (info != NULL && info->irq) {
+ if (!xen_initial_domain())
+ xen_console_update_evtchn(info);
rebind_evtchn_irq(info->evtchn, info->irq);
+ }
}
+#ifdef CONFIG_HVC_XEN_FRONTEND
static void xencons_disconnect_backend(struct xencons_info *info)
{
- if (info->irq > 0)
- unbind_from_irqhandler(info->irq, NULL);
- info->irq = 0;
+ if (info->hvc != NULL)
+ hvc_remove(info->hvc);
+ info->hvc = NULL;
+ if (info->irq > 0) {
+ evtchn_put(info->evtchn);
+ info->irq = 0;
+ info->evtchn = 0;
+ }
+ /* evtchn_put() will also close it so this is only an error path */
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)
@@ -332,10 +405,12 @@ static void xencons_free(struct xencons_info *info)
static int xen_console_remove(struct xencons_info *info)
{
+ unsigned long flags;
+
xencons_disconnect_backend(info);
- spin_lock(&xencons_lock);
+ spin_lock_irqsave(&xencons_lock, flags);
list_del(&info->list);
- spin_unlock(&xencons_lock);
+ spin_unlock_irqrestore(&xencons_lock, flags);
if (info->xbdev != NULL)
xencons_free(info);
else {
@@ -346,12 +421,9 @@ static int xen_console_remove(struct xencons_info *info)
return 0;
}
-#ifdef CONFIG_HVC_XEN_FRONTEND
-static struct xenbus_driver xencons_driver;
-
-static int xencons_remove(struct xenbus_device *dev)
+static void xencons_remove(struct xenbus_device *dev)
{
- return xen_console_remove(dev_get_drvdata(&dev->dev));
+ xen_console_remove(dev_get_drvdata(&dev->dev));
}
static int xencons_connect_backend(struct xenbus_device *dev,
@@ -360,13 +432,12 @@ static int xencons_connect_backend(struct xenbus_device *dev,
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);
+ irq = bind_evtchn_to_irq_lateeoi(evtchn);
if (irq < 0)
return irq;
info->irq = irq;
@@ -375,10 +446,6 @@ static int xencons_connect_backend(struct xenbus_device *dev,
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;
@@ -387,7 +454,7 @@ static int xencons_connect_backend(struct xenbus_device *dev,
if (ref < 0)
return ref;
gnttab_grant_foreign_access_ref(ref, info->xbdev->otherend_id,
- mfn, 0);
+ virt_to_gfn(info->intf), 0);
again:
ret = xenbus_transaction_start(&xbt);
@@ -402,9 +469,6 @@ static int xencons_connect_backend(struct xenbus_device *dev,
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)
@@ -427,6 +491,7 @@ static int xencons_probe(struct xenbus_device *dev,
{
int ret, devid;
struct xencons_info *info;
+ unsigned long flags;
devid = dev->nodename[strlen(dev->nodename) - 1] - '0';
if (devid == 0)
@@ -435,6 +500,7 @@ static int xencons_probe(struct xenbus_device *dev,
info = kzalloc(sizeof(struct xencons_info), GFP_KERNEL);
if (!info)
return -ENOMEM;
+ spin_lock_init(&info->ring_lock);
dev_set_drvdata(&dev->dev, info);
info->xbdev = dev;
info->vtermno = xenbus_devid_to_vtermno(devid);
@@ -445,9 +511,9 @@ static int xencons_probe(struct xenbus_device *dev,
ret = xencons_connect_backend(dev, info);
if (ret < 0)
goto error;
- spin_lock(&xencons_lock);
+ spin_lock_irqsave(&xencons_lock, flags);
list_add_tail(&info->list, &xenconsoles);
- spin_unlock(&xencons_lock);
+ spin_unlock_irqrestore(&xencons_lock, flags);
return 0;
@@ -465,7 +531,7 @@ 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);
+ memset(info->intf, 0, XEN_PAGE_SIZE);
return xencons_connect_backend(dev, info);
}
@@ -490,11 +556,24 @@ static void xencons_backend_changed(struct xenbus_device *dev,
case XenbusStateClosed:
if (dev->state == XenbusStateClosed)
break;
- /* Missed the backend's CLOSING state -- fallthrough */
- case XenbusStateClosing:
+ fallthrough; /* Missed the backend's CLOSING state */
+ case XenbusStateClosing: {
+ struct xencons_info *info = dev_get_drvdata(&dev->dev);
+
+ /*
+ * Don't tear down the evtchn and grant ref before the other
+ * end has disconnected, but do stop userspace from trying
+ * to use the device before we allow the backend to close.
+ */
+ if (info->hvc) {
+ hvc_remove(info->hvc);
+ info->hvc = NULL;
+ }
+
xenbus_frontend_closed(dev);
break;
}
+ }
}
static const struct xenbus_device_id xencons_ids[] = {
@@ -502,13 +581,15 @@ static const struct xenbus_device_id xencons_ids[] = {
{ "" }
};
-
-static DEFINE_XENBUS_DRIVER(xencons, "xenconsole",
+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,
-);
+ .not_essential = true,
+};
#endif /* CONFIG_HVC_XEN_FRONTEND */
static int __init xen_hvc_init(void)
@@ -524,7 +605,7 @@ static int __init xen_hvc_init(void)
ops = &dom0_hvc_ops;
r = xen_initial_domain_console_init();
if (r < 0)
- return r;
+ goto register_fe;
info = vtermno_to_xencons(HVC_COOKIE);
} else {
ops = &domU_hvc_ops;
@@ -533,10 +614,10 @@ static int __init xen_hvc_init(void)
else
r = xen_pv_console_init();
if (r < 0)
- return r;
+ goto register_fe;
info = vtermno_to_xencons(HVC_COOKIE);
- info->irq = bind_evtchn_to_irq(info->evtchn);
+ info->irq = bind_evtchn_to_irq_lateeoi(info->evtchn);
}
if (info->irq < 0)
info->irq = 0; /* NO_IRQ */
@@ -545,34 +626,26 @@ static int __init xen_hvc_init(void)
info->hvc = hvc_alloc(HVC_COOKIE, info->irq, ops, 256);
if (IS_ERR(info->hvc)) {
+ unsigned long flags;
+
r = PTR_ERR(info->hvc);
- spin_lock(&xencons_lock);
+ spin_lock_irqsave(&xencons_lock, flags);
list_del(&info->list);
- spin_unlock(&xencons_lock);
+ spin_unlock_irqrestore(&xencons_lock, flags);
if (info->irq)
- unbind_from_irqhandler(info->irq, NULL);
+ evtchn_put(info->evtchn);
kfree(info);
return r;
}
r = 0;
+ register_fe:
#ifdef CONFIG_HVC_XEN_FRONTEND
r = xenbus_register_frontend(&xencons_driver);
#endif
return r;
}
-
-static void __exit xen_hvc_fini(void)
-{
- struct xencons_info *entry, *next;
-
- if (list_empty(&xenconsoles))
- return;
-
- list_for_each_entry_safe(entry, next, &xenconsoles, list) {
- xen_console_remove(entry);
- }
-}
+device_initcall(xen_hvc_init);
static int xen_cons_init(void)
{
@@ -598,28 +671,45 @@ static int xen_cons_init(void)
hvc_instantiate(HVC_COOKIE, 0, ops);
return 0;
}
-
-
-module_init(xen_hvc_init);
-module_exit(xen_hvc_fini);
console_initcall(xen_cons_init);
+#ifdef CONFIG_X86
+static void xen_hvm_early_write(uint32_t vtermno, const char *str, int len)
+{
+ if (xen_cpuid_base())
+ outsb(0xe9, str, len);
+}
+#else
+static void xen_hvm_early_write(uint32_t vtermno, const char *str, int len) { }
+#endif
+
#ifdef CONFIG_EARLY_PRINTK
+static int __init xenboot_console_setup(struct console *console, char *string)
+{
+ static struct xencons_info xenboot;
+
+ if (xen_initial_domain() || !xen_pv_domain())
+ return 0;
+
+ return xencons_info_pv_init(&xenboot, 0);
+}
+
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())
+ if (dom0_write_console(0, string, len) >= 0)
return;
- dom0_write_console(0, string, len);
-
- if (xen_initial_domain())
+ if (!xen_pv_domain()) {
+ xen_hvm_early_write(0, string, len);
return;
+ }
- domU_write_console(0, "(early) ", 8);
+ if (domU_write_console(0, "(early) ", 8) < 0)
+ return;
while (off < len && NULL != (pos = strchr(string+off, '\n'))) {
linelen = pos-string+off;
if (off + linelen > len)
@@ -635,13 +725,23 @@ static void xenboot_write_console(struct console *console, const char *string,
struct console xenboot_console = {
.name = "xenboot",
.write = xenboot_write_console,
+ .setup = xenboot_console_setup,
.flags = CON_PRINTBUFFER | CON_BOOT | CON_ANYTIME,
+ .index = -1,
};
#endif /* CONFIG_EARLY_PRINTK */
void xen_raw_console_write(const char *str)
{
- dom0_write_console(0, str, strlen(str));
+ ssize_t len = strlen(str);
+ int rc = 0;
+
+ if (xen_domain()) {
+ rc = dom0_write_console(0, str, len);
+ if (rc != -ENOSYS || !xen_hvm_domain())
+ return;
+ }
+ xen_hvm_early_write(0, str, len);
}
void xen_raw_printk(const char *fmt, ...)
@@ -655,3 +755,18 @@ void xen_raw_printk(const char *fmt, ...)
xen_raw_console_write(buf);
}
+
+static void xenboot_earlycon_write(struct console *console,
+ const char *string,
+ unsigned len)
+{
+ dom0_write_console(0, string, len);
+}
+
+static int __init xenboot_earlycon_setup(struct earlycon_device *device,
+ const char *opt)
+{
+ device->con->write = xenboot_earlycon_write;
+ return 0;
+}
+EARLYCON_DECLARE(xenboot, xenboot_earlycon_setup);
generated by cgit (git 2.34.1) at 2025-12-25 07:19:32 +0000