freebsd-skq/sys/dev/xen/console/console.c
avg f6def40e18 kern cons: introduce infrastructure for console grabbing by kernel
At the moment grab and ungrab methods of all console drivers are no-ops.

Current intended meaning of the calls is that the kernel takes control of
console input.  In the future the semantics may be extended to mean that
the calling thread takes full ownership of the console (e.g. console
output from other threads could be suspended).

Inspired by:	bde
MFC after:	2 months
2011-12-17 15:08:43 +00:00

444 lines
8.1 KiB
C

#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <sys/param.h>
#include <sys/module.h>
#include <sys/systm.h>
#include <sys/consio.h>
#include <sys/priv.h>
#include <sys/proc.h>
#include <sys/uio.h>
#include <sys/tty.h>
#include <sys/systm.h>
#include <sys/taskqueue.h>
#include <sys/conf.h>
#include <sys/kernel.h>
#include <sys/bus.h>
#include <machine/stdarg.h>
#include <machine/xen/xen-os.h>
#include <xen/hypervisor.h>
#include <xen/xen_intr.h>
#include <sys/cons.h>
#include <sys/kdb.h>
#include <sys/proc.h>
#include <dev/xen/console/xencons_ring.h>
#include <xen/interface/io/console.h>
#include "opt_ddb.h"
#ifdef DDB
#include <ddb/ddb.h>
#endif
static char driver_name[] = "xc";
devclass_t xc_devclass; /* do not make static */
static void xcoutwakeup(struct tty *);
static void xc_timeout(void *);
static void __xencons_tx_flush(void);
static boolean_t xcons_putc(int c);
/* switch console so that shutdown can occur gracefully */
static void xc_shutdown(void *arg, int howto);
static int xc_mute;
static void xcons_force_flush(void);
static void xencons_priv_interrupt(void *);
static cn_probe_t xc_cnprobe;
static cn_init_t xc_cninit;
static cn_term_t xc_cnterm;
static cn_getc_t xc_cngetc;
static cn_putc_t xc_cnputc;
static cn_grab_t xc_cngrab;
static cn_ungrab_t xc_cnungrab;
#define XC_POLLTIME (hz/10)
CONSOLE_DRIVER(xc);
static int xen_console_up;
static boolean_t xc_start_needed;
static struct callout xc_callout;
struct mtx cn_mtx;
#define RBUF_SIZE 1024
#define RBUF_MASK(_i) ((_i)&(RBUF_SIZE-1))
#define WBUF_SIZE 4096
#define WBUF_MASK(_i) ((_i)&(WBUF_SIZE-1))
static char wbuf[WBUF_SIZE];
static char rbuf[RBUF_SIZE];
static int rc, rp;
static unsigned int cnsl_evt_reg;
static unsigned int wc, wp; /* write_cons, write_prod */
#ifdef KDB
static int xc_altbrk;
#endif
#define CDEV_MAJOR 12
#define XCUNIT(x) (dev2unit(x))
#define ISTTYOPEN(tp) ((tp) && ((tp)->t_state & TS_ISOPEN))
#define CN_LOCK_INIT(x, _name) \
mtx_init(&x, _name, NULL, MTX_SPIN|MTX_RECURSE)
#define CN_LOCK(l) \
do { \
if (panicstr == NULL) \
mtx_lock_spin(&(l)); \
} while (0)
#define CN_UNLOCK(l) \
do { \
if (panicstr == NULL) \
mtx_unlock_spin(&(l)); \
} while (0)
#define CN_LOCK_ASSERT(x) mtx_assert(&x, MA_OWNED)
#define CN_LOCK_DESTROY(x) mtx_destroy(&x)
static struct tty *xccons;
static tsw_open_t xcopen;
static tsw_close_t xcclose;
static struct ttydevsw xc_ttydevsw = {
.tsw_flags = TF_NOPREFIX,
.tsw_open = xcopen,
.tsw_close = xcclose,
.tsw_outwakeup = xcoutwakeup,
};
static void
xc_cnprobe(struct consdev *cp)
{
cp->cn_pri = CN_REMOTE;
sprintf(cp->cn_name, "%s0", driver_name);
}
static void
xc_cninit(struct consdev *cp)
{
CN_LOCK_INIT(cn_mtx,"XCONS LOCK");
}
static void
xc_cnterm(struct consdev *cp)
{
}
static void
xc_cngrab(struct consdev *cp)
{
}
static void
xc_cnungrab(struct consdev *cp)
{
}
static int
xc_cngetc(struct consdev *dev)
{
int ret;
if (xencons_has_input())
xencons_handle_input(NULL);
CN_LOCK(cn_mtx);
if ((rp - rc) && !xc_mute) {
/* we need to return only one char */
ret = (int)rbuf[RBUF_MASK(rc)];
rc++;
} else
ret = -1;
CN_UNLOCK(cn_mtx);
return(ret);
}
static void
xc_cnputc_domu(struct consdev *dev, int c)
{
xcons_putc(c);
}
static void
xc_cnputc_dom0(struct consdev *dev, int c)
{
HYPERVISOR_console_io(CONSOLEIO_write, 1, (char *)&c);
}
static void
xc_cnputc(struct consdev *dev, int c)
{
if (xen_start_info->flags & SIF_INITDOMAIN)
xc_cnputc_dom0(dev, c);
else
xc_cnputc_domu(dev, c);
}
extern int db_active;
static boolean_t
xcons_putc(int c)
{
int force_flush = xc_mute ||
#ifdef DDB
db_active ||
#endif
panicstr; /* we're not gonna recover, so force
* flush
*/
if ((wp-wc) < (WBUF_SIZE-1)) {
if ((wbuf[WBUF_MASK(wp++)] = c) == '\n') {
wbuf[WBUF_MASK(wp++)] = '\r';
#ifdef notyet
if (force_flush)
xcons_force_flush();
#endif
}
} else if (force_flush) {
#ifdef notyet
xcons_force_flush();
#endif
}
if (cnsl_evt_reg)
__xencons_tx_flush();
/* inform start path that we're pretty full */
return ((wp - wc) >= WBUF_SIZE - 100) ? TRUE : FALSE;
}
static void
xc_identify(driver_t *driver, device_t parent)
{
device_t child;
child = BUS_ADD_CHILD(parent, 0, driver_name, 0);
device_set_driver(child, driver);
device_set_desc(child, "Xen Console");
}
static int
xc_probe(device_t dev)
{
return (0);
}
static int
xc_attach(device_t dev)
{
int error;
xccons = tty_alloc(&xc_ttydevsw, NULL);
tty_makedev(xccons, NULL, "xc%r", 0);
callout_init(&xc_callout, 0);
xencons_ring_init();
cnsl_evt_reg = 1;
callout_reset(&xc_callout, XC_POLLTIME, xc_timeout, xccons);
if (xen_start_info->flags & SIF_INITDOMAIN) {
error = bind_virq_to_irqhandler(
VIRQ_CONSOLE,
0,
"console",
NULL,
xencons_priv_interrupt, NULL,
INTR_TYPE_TTY, NULL);
KASSERT(error >= 0, ("can't register console interrupt"));
}
/* register handler to flush console on shutdown */
if ((EVENTHANDLER_REGISTER(shutdown_post_sync, xc_shutdown,
NULL, SHUTDOWN_PRI_DEFAULT)) == NULL)
printf("xencons: shutdown event registration failed!\n");
return (0);
}
/*
* return 0 for all console input, force flush all output.
*/
static void
xc_shutdown(void *arg, int howto)
{
xc_mute = 1;
xcons_force_flush();
}
void
xencons_rx(char *buf, unsigned len)
{
int i;
struct tty *tp = xccons;
if (xen_console_up
#ifdef DDB
&& !kdb_active
#endif
) {
tty_lock(tp);
for (i = 0; i < len; i++) {
#ifdef KDB
kdb_alt_break(buf[i], &xc_altbrk);
#endif
ttydisc_rint(tp, buf[i], 0);
}
ttydisc_rint_done(tp);
tty_unlock(tp);
} else {
CN_LOCK(cn_mtx);
for (i = 0; i < len; i++)
rbuf[RBUF_MASK(rp++)] = buf[i];
CN_UNLOCK(cn_mtx);
}
}
static void
__xencons_tx_flush(void)
{
int sz;
CN_LOCK(cn_mtx);
while (wc != wp) {
int sent;
sz = wp - wc;
if (sz > (WBUF_SIZE - WBUF_MASK(wc)))
sz = WBUF_SIZE - WBUF_MASK(wc);
if (xen_start_info->flags & SIF_INITDOMAIN) {
HYPERVISOR_console_io(CONSOLEIO_write, sz, &wbuf[WBUF_MASK(wc)]);
wc += sz;
} else {
sent = xencons_ring_send(&wbuf[WBUF_MASK(wc)], sz);
if (sent == 0)
break;
wc += sent;
}
}
CN_UNLOCK(cn_mtx);
}
void
xencons_tx(void)
{
__xencons_tx_flush();
}
static void
xencons_priv_interrupt(void *arg)
{
static char rbuf[16];
int l;
while ((l = HYPERVISOR_console_io(CONSOLEIO_read, 16, rbuf)) > 0)
xencons_rx(rbuf, l);
xencons_tx();
}
static int
xcopen(struct tty *tp)
{
xen_console_up = 1;
return (0);
}
static void
xcclose(struct tty *tp)
{
xen_console_up = 0;
}
static inline int
__xencons_put_char(int ch)
{
char _ch = (char)ch;
if ((wp - wc) == WBUF_SIZE)
return 0;
wbuf[WBUF_MASK(wp++)] = _ch;
return 1;
}
static void
xcoutwakeup(struct tty *tp)
{
boolean_t cons_full = FALSE;
char c;
while (ttydisc_getc(tp, &c, 1) == 1 && !cons_full)
cons_full = xcons_putc(c);
if (cons_full) {
/* let the timeout kick us in a bit */
xc_start_needed = TRUE;
}
}
static void
xc_timeout(void *v)
{
struct tty *tp;
int c;
tp = (struct tty *)v;
tty_lock(tp);
while ((c = xc_cngetc(NULL)) != -1)
ttydisc_rint(tp, c, 0);
if (xc_start_needed) {
xc_start_needed = FALSE;
xcoutwakeup(tp);
}
tty_unlock(tp);
callout_reset(&xc_callout, XC_POLLTIME, xc_timeout, tp);
}
static device_method_t xc_methods[] = {
DEVMETHOD(device_identify, xc_identify),
DEVMETHOD(device_probe, xc_probe),
DEVMETHOD(device_attach, xc_attach),
{0, 0}
};
static driver_t xc_driver = {
driver_name,
xc_methods,
0,
};
/*** Forcibly flush console data before dying. ***/
void
xcons_force_flush(void)
{
int sz;
if (xen_start_info->flags & SIF_INITDOMAIN)
return;
/* Spin until console data is flushed through to the domain controller. */
while (wc != wp) {
int sent = 0;
if ((sz = wp - wc) == 0)
continue;
sent = xencons_ring_send(&wbuf[WBUF_MASK(wc)], sz);
if (sent > 0)
wc += sent;
}
}
DRIVER_MODULE(xc, nexus, xc_driver, xc_devclass, 0, 0);