linux/drivers/char/hvc_xen.c
Jeremy Fitzhardinge 6b9b732d0e xen-console: add save/restore
Add code to:

 1. Deal with the console page being canonicalized.  During save, the
    console's mfn in the start_info structure is canonicalized to a pfn.
    In order to deal with that, we always use a copy of the pfn and
    indirect off that all the time.  However, we fall back to using the
    mfn if the pfn hasn't been initialized yet.

 2. Restore the console event channel, and rebind it to the existing irq.

Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-27 10:11:37 +02:00

211 lines
4.8 KiB
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/init.h>
#include <linux/types.h>
#include <asm/xen/hypervisor.h>
#include <xen/page.h>
#include <xen/events.h>
#include <xen/interface/io/console.h>
#include <xen/hvc-console.h>
#include "hvc_console.h"
#define HVC_COOKIE 0x58656e /* "Xen" in hex */
static struct hvc_struct *hvc;
static int xencons_irq;
/* ------------------------------------------------------------------ */
static unsigned long console_pfn = ~0ul;
static inline struct xencons_interface *xencons_interface(void)
{
if (console_pfn == ~0ul)
return mfn_to_virt(xen_start_info->console.domU.mfn);
else
return __va(console_pfn << PAGE_SHIFT);
}
static inline void notify_daemon(void)
{
/* Use evtchn: this is called early, before irq is set up. */
notify_remote_via_evtchn(xen_start_info->console.domU.evtchn);
}
static int write_console(uint32_t vtermno, const char *data, int len)
{
struct xencons_interface *intf = xencons_interface();
XENCONS_RING_IDX cons, prod;
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;
notify_daemon();
return sent;
}
static int read_console(uint32_t vtermno, char *buf, int len)
{
struct xencons_interface *intf = xencons_interface();
XENCONS_RING_IDX cons, prod;
int recv = 0;
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();
return recv;
}
static struct hv_ops hvc_ops = {
.get_chars = read_console,
.put_chars = write_console,
};
static int __init xen_init(void)
{
struct hvc_struct *hp;
if (!is_running_on_xen() ||
is_initial_xendomain() ||
!xen_start_info->console.domU.evtchn)
return -ENODEV;
xencons_irq = bind_evtchn_to_irq(xen_start_info->console.domU.evtchn);
if (xencons_irq < 0)
xencons_irq = 0; /* NO_IRQ */
hp = hvc_alloc(HVC_COOKIE, xencons_irq, &hvc_ops, 256);
if (IS_ERR(hp))
return PTR_ERR(hp);
hvc = hp;
console_pfn = mfn_to_pfn(xen_start_info->console.domU.mfn);
return 0;
}
void xen_console_resume(void)
{
if (xencons_irq)
rebind_evtchn_irq(xen_start_info->console.domU.evtchn, xencons_irq);
}
static void __exit xen_fini(void)
{
if (hvc)
hvc_remove(hvc);
}
static int xen_cons_init(void)
{
if (!is_running_on_xen())
return 0;
hvc_instantiate(HVC_COOKIE, 0, &hvc_ops);
return 0;
}
module_init(xen_init);
module_exit(xen_fini);
console_initcall(xen_cons_init);
static void raw_console_write(const char *str, int len)
{
while(len > 0) {
int rc = HYPERVISOR_console_io(CONSOLEIO_write, len, (char *)str);
if (rc <= 0)
break;
str += rc;
len -= rc;
}
}
#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;
raw_console_write(string, len);
write_console(0, "(early) ", 8);
while (off < len && NULL != (pos = strchr(string+off, '\n'))) {
linelen = pos-string+off;
if (off + linelen > len)
break;
write_console(0, string+off, linelen);
write_console(0, "\r\n", 2);
off += linelen + 1;
}
if (off < len)
write_console(0, string+off, len-off);
}
struct console xenboot_console = {
.name = "xenboot",
.write = xenboot_write_console,
.flags = CON_PRINTBUFFER | CON_BOOT | CON_ANYTIME,
};
#endif /* CONFIG_EARLY_PRINTK */
void xen_raw_console_write(const char *str)
{
raw_console_write(str, strlen(str));
}
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);
}