// SPDX-License-Identifier: GPL-2.0+
|
/*
|
* xen console driver interface to hvc_console.c
|
*
|
* (c) 2007 Gerd Hoffmann <kraxel@suse.de>
|
*/
|
|
#include <linux/console.h>
|
#include <linux/delay.h>
|
#include <linux/err.h>
|
#include <linux/irq.h>
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#include <linux/init.h>
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#include <linux/types.h>
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#include <linux/list.h>
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#include <linux/serial_core.h>
|
|
#include <asm/io.h>
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#include <asm/xen/hypervisor.h>
|
|
#include <xen/xen.h>
|
#include <xen/interface/xen.h>
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#include <xen/hvm.h>
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#include <xen/grant_table.h>
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#include <xen/page.h>
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#include <xen/events.h>
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#include <xen/interface/io/console.h>
|
#include <xen/interface/sched.h>
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#include <xen/hvc-console.h>
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#include <xen/xenbus.h>
|
|
#include "hvc_console.h"
|
|
#define HVC_COOKIE 0x58656e /* "Xen" in hex */
|
|
struct xencons_info {
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struct list_head list;
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struct xenbus_device *xbdev;
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struct xencons_interface *intf;
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unsigned int evtchn;
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XENCONS_RING_IDX out_cons;
|
unsigned int out_cons_same;
|
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;
|
}
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|
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 */
|
|
if ((prod - cons) > sizeof(intf->out)) {
|
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 */
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intf->out_prod = prod;
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if (sent)
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notify_daemon(xencons);
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return sent;
|
}
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|
static int domU_write_console(uint32_t vtermno, const char *data, int len)
|
{
|
int ret = len;
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struct xencons_info *cons = vtermno_to_xencons(vtermno);
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if (cons == NULL)
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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) {
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int sent = __write_console(cons, data, len);
|
|
if (sent < 0)
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return sent;
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|
data += sent;
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len -= sent;
|
|
if (unlikely(len))
|
HYPERVISOR_sched_op(SCHEDOP_yield, NULL);
|
}
|
|
return ret;
|
}
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|
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);
|
unsigned int eoiflag = 0;
|
|
if (xencons == NULL)
|
return -EINVAL;
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intf = xencons->intf;
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|
cons = intf->in_cons;
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prod = intf->in_prod;
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mb(); /* get pointers before reading ring */
|
|
if ((prod - cons) > sizeof(intf->in)) {
|
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)];
|
|
mb(); /* read ring before consuming */
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intf->in_cons = cons;
|
|
/*
|
* 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;
|
}
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if (recv) {
|
notify_daemon(xencons);
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} else if (xencons->out_cons_same++ > 1) {
|
eoiflag = XEN_EOI_FLAG_SPURIOUS;
|
}
|
|
xen_irq_lateeoi(xencons->irq, eoiflag);
|
|
return recv;
|
}
|
|
static const 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,
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.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 const 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 gfn;
|
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 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.
|
*/
|
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;
|
gfn = v;
|
info->intf = xen_remap(gfn << XEN_PAGE_SHIFT, XEN_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 xencons_info_pv_init(struct xencons_info *info, int vtermno)
|
{
|
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;
|
|
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;
|
}
|
spin_lock(&xencons_lock);
|
xencons_info_pv_init(info, HVC_COOKIE);
|
spin_unlock(&xencons_lock);
|
|
return 0;
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}
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|
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, false);
|
info->vtermno = HVC_COOKIE;
|
|
spin_lock(&xencons_lock);
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list_add_tail(&info->list, &xenconsoles);
|
spin_unlock(&xencons_lock);
|
|
return 0;
|
}
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|
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 (!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->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;
|
}
|
|
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;
|
|
ret = xenbus_alloc_evtchn(dev, &evtchn);
|
if (ret)
|
return ret;
|
info->evtchn = evtchn;
|
irq = bind_interdomain_evtchn_to_irq_lateeoi(dev->otherend_id, 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);
|
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,
|
virt_to_gfn(info->intf), 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, XEN_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;
|
fallthrough; /* Missed the backend's CLOSING state */
|
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_lateeoi(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_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())
|
return 0;
|
if (!xen_pv_domain())
|
return -ENODEV;
|
|
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()) {
|
xen_hvm_early_write(0, string, len);
|
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,
|
.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)
|
{
|
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, ...)
|
{
|
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);
|
}
|
|
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);
|
