freebsd-dev/sys/dev/dcons/dcons_os.c
Ed Schouten bc093719ca Integrate the new MPSAFE TTY layer to the FreeBSD operating system.
The last half year I've been working on a replacement TTY layer for the
FreeBSD kernel. The new TTY layer was designed to improve the following:

- Improved driver model:

  The old TTY layer has a driver model that is not abstract enough to
  make it friendly to use. A good example is the output path, where the
  device drivers directly access the output buffers. This means that an
  in-kernel PPP implementation must always convert network buffers into
  TTY buffers.

  If a PPP implementation would be built on top of the new TTY layer
  (still needs a hooks layer, though), it would allow the PPP
  implementation to directly hand the data to the TTY driver.

- Improved hotplugging:

  With the old TTY layer, it isn't entirely safe to destroy TTY's from
  the system. This implementation has a two-step destructing design,
  where the driver first abandons the TTY. After all threads have left
  the TTY, the TTY layer calls a routine in the driver, which can be
  used to free resources (unit numbers, etc).

  The pts(4) driver also implements this feature, which means
  posix_openpt() will now return PTY's that are created on the fly.

- Improved performance:

  One of the major improvements is the per-TTY mutex, which is expected
  to improve scalability when compared to the old Giant locking.
  Another change is the unbuffered copying to userspace, which is both
  used on TTY device nodes and PTY masters.

Upgrading should be quite straightforward. Unlike previous versions,
existing kernel configuration files do not need to be changed, except
when they reference device drivers that are listed in UPDATING.

Obtained from:		//depot/projects/mpsafetty/...
Approved by:		philip (ex-mentor)
Discussed:		on the lists, at BSDCan, at the DevSummit
Sponsored by:		Snow B.V., the Netherlands
dcons(4) fixed by:	kan
2008-08-20 08:31:58 +00:00

483 lines
10 KiB
C

/*-
* Copyright (C) 2003,2004
* Hidetoshi Shimokawa. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
*
* This product includes software developed by Hidetoshi Shimokawa.
*
* 4. Neither the name of the author nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* $FreeBSD$
*/
#include <sys/param.h>
#include <sys/kdb.h>
#include <gdb/gdb.h>
#include <sys/kernel.h>
#include <sys/module.h>
#include <sys/systm.h>
#include <sys/types.h>
#include <sys/conf.h>
#include <sys/cons.h>
#include <sys/consio.h>
#include <sys/tty.h>
#include <sys/malloc.h>
#include <sys/priv.h>
#include <sys/proc.h>
#include <sys/ucred.h>
#include <machine/bus.h>
#include <dev/dcons/dcons.h>
#include <dev/dcons/dcons_os.h>
#include <ddb/ddb.h>
#include <sys/reboot.h>
#include <sys/sysctl.h>
#include <vm/vm.h>
#include <vm/vm_param.h>
#include <vm/pmap.h>
#include "opt_comconsole.h"
#include "opt_dcons.h"
#include "opt_kdb.h"
#include "opt_gdb.h"
#include "opt_ddb.h"
#ifndef DCONS_POLL_HZ
#define DCONS_POLL_HZ 100
#endif
#ifndef DCONS_BUF_SIZE
#define DCONS_BUF_SIZE (16*1024)
#endif
#ifndef DCONS_FORCE_CONSOLE
#define DCONS_FORCE_CONSOLE 0 /* Mostly for FreeBSD-4/DragonFly */
#endif
#ifndef KLD_MODULE
static char bssbuf[DCONS_BUF_SIZE]; /* buf in bss */
#endif
/* global data */
static struct dcons_global dg;
struct dcons_global *dcons_conf;
static int poll_hz = DCONS_POLL_HZ;
static struct dcons_softc sc[DCONS_NPORT];
SYSCTL_NODE(_kern, OID_AUTO, dcons, CTLFLAG_RD, 0, "Dumb Console");
SYSCTL_INT(_kern_dcons, OID_AUTO, poll_hz, CTLFLAG_RW, &poll_hz, 0,
"dcons polling rate");
static int drv_init = 0;
static struct callout dcons_callout;
struct dcons_buf *dcons_buf; /* for local dconschat */
static void dcons_timeout(void *);
static int dcons_drv_init(int);
static cn_probe_t dcons_cnprobe;
static cn_init_t dcons_cninit;
static cn_term_t dcons_cnterm;
static cn_getc_t dcons_cngetc;
static cn_putc_t dcons_cnputc;
CONSOLE_DRIVER(dcons);
#if defined(GDB)
static gdb_probe_f dcons_dbg_probe;
static gdb_init_f dcons_dbg_init;
static gdb_term_f dcons_dbg_term;
static gdb_getc_f dcons_dbg_getc;
static gdb_putc_f dcons_dbg_putc;
GDB_DBGPORT(dcons, dcons_dbg_probe, dcons_dbg_init, dcons_dbg_term,
dcons_dbg_getc, dcons_dbg_putc);
extern struct gdb_dbgport *gdb_cur;
#endif
static tsw_outwakeup_t dcons_outwakeup;
static struct ttydevsw dcons_ttydevsw = {
.tsw_flags = TF_NOPREFIX,
.tsw_outwakeup = dcons_outwakeup,
};
#if (defined(GDB) || defined(DDB)) && defined(ALT_BREAK_TO_DEBUGGER)
static int
dcons_check_break(struct dcons_softc *dc, int c)
{
int kdb_brk;
if (c < 0)
return (c);
if ((kdb_brk = kdb_alt_break(c, &dc->brk_state)) != 0) {
switch (kdb_brk) {
case KDB_REQ_DEBUGGER:
if ((dc->flags & DC_GDB) != 0) {
#ifdef GDB
if (gdb_cur == &dcons_gdb_dbgport) {
kdb_dbbe_select("gdb");
kdb_enter(KDB_WHY_BREAK,
"Break sequence on dcons gdb port");
}
#endif
} else
kdb_enter(KDB_WHY_BREAK,
"Break sequence on dcons console port");
break;
case KDB_REQ_PANIC:
kdb_panic("Panic sequence on dcons console port");
break;
case KDB_REQ_REBOOT:
kdb_reboot();
break;
}
}
return (c);
}
#else
#define dcons_check_break(dc, c) (c)
#endif
static int
dcons_os_checkc_nopoll(struct dcons_softc *dc)
{
int c;
if (dg.dma_tag != NULL)
bus_dmamap_sync(dg.dma_tag, dg.dma_map, BUS_DMASYNC_POSTREAD);
c = dcons_check_break(dc, dcons_checkc(dc));
if (dg.dma_tag != NULL)
bus_dmamap_sync(dg.dma_tag, dg.dma_map, BUS_DMASYNC_PREREAD);
return (c);
}
static int
dcons_os_checkc(struct dcons_softc *dc)
{
EVENTHANDLER_INVOKE(dcons_poll, 0);
return (dcons_os_checkc_nopoll(dc));
}
static void
dcons_os_putc(struct dcons_softc *dc, int c)
{
if (dg.dma_tag != NULL)
bus_dmamap_sync(dg.dma_tag, dg.dma_map, BUS_DMASYNC_POSTWRITE);
dcons_putc(dc, c);
if (dg.dma_tag != NULL)
bus_dmamap_sync(dg.dma_tag, dg.dma_map, BUS_DMASYNC_PREWRITE);
}
static void
dcons_outwakeup(struct tty *tp)
{
struct dcons_softc *dc;
char ch;
dc = tty_softc(tp);
while (ttydisc_getc(tp, &ch, sizeof ch) != 0)
dcons_os_putc(dc, ch);
}
static void
dcons_timeout(void *v)
{
struct tty *tp;
struct dcons_softc *dc;
int i, c, polltime;
for (i = 0; i < DCONS_NPORT; i ++) {
dc = &sc[i];
tp = dc->tty;
tty_lock(tp);
while ((c = dcons_os_checkc_nopoll(dc)) != -1)
ttydisc_rint(tp, c, 0);
ttydisc_rint_done(tp);
tty_unlock(tp);
}
polltime = hz / poll_hz;
if (polltime < 1)
polltime = 1;
callout_reset(&dcons_callout, polltime, dcons_timeout, tp);
}
static void
dcons_cnprobe(struct consdev *cp)
{
sprintf(cp->cn_name, "dcons");
#if DCONS_FORCE_CONSOLE
cp->cn_pri = CN_REMOTE;
#else
cp->cn_pri = CN_NORMAL;
#endif
}
static void
dcons_cninit(struct consdev *cp)
{
dcons_drv_init(0);
cp->cn_arg = (void *)&sc[DCONS_CON]; /* share port0 with unit0 */
}
static void
dcons_cnterm(struct consdev *cp)
{
}
static int
dcons_cngetc(struct consdev *cp)
{
struct dcons_softc *dc = (struct dcons_softc *)cp->cn_arg;
return (dcons_os_checkc(dc));
}
static void
dcons_cnputc(struct consdev *cp, int c)
{
struct dcons_softc *dc = (struct dcons_softc *)cp->cn_arg;
dcons_os_putc(dc, c);
}
static int
dcons_drv_init(int stage)
{
#if defined(__i386__) || defined(__amd64__)
quad_t addr, size;
#endif
if (drv_init)
return(drv_init);
drv_init = -1;
bzero(&dg, sizeof(dg));
dcons_conf = &dg;
dg.cdev = &dcons_consdev;
dg.buf = NULL;
dg.size = DCONS_BUF_SIZE;
#if defined(__i386__) || defined(__amd64__)
if (getenv_quad("dcons.addr", &addr) > 0 &&
getenv_quad("dcons.size", &size) > 0) {
#ifdef __i386__
vm_paddr_t pa;
/*
* Allow read/write access to dcons buffer.
*/
for (pa = trunc_page(addr); pa < addr + size; pa += PAGE_SIZE)
*vtopte(KERNBASE + pa) |= PG_RW;
invltlb();
#endif
/* XXX P to V */
dg.buf = (struct dcons_buf *)(vm_offset_t)(KERNBASE + addr);
dg.size = size;
if (dcons_load_buffer(dg.buf, dg.size, sc) < 0)
dg.buf = NULL;
}
#endif
if (dg.buf != NULL)
goto ok;
#ifndef KLD_MODULE
if (stage == 0) { /* XXX or cold */
/*
* DCONS_FORCE_CONSOLE == 1 and statically linked.
* called from cninit(). can't use contigmalloc yet .
*/
dg.buf = (struct dcons_buf *) bssbuf;
dcons_init(dg.buf, dg.size, sc);
} else
#endif
{
/*
* DCONS_FORCE_CONSOLE == 0 or kernel module case.
* if the module is loaded after boot,
* bssbuf could be non-continuous.
*/
dg.buf = (struct dcons_buf *) contigmalloc(dg.size,
M_DEVBUF, 0, 0x10000, 0xffffffff, PAGE_SIZE, 0ul);
dcons_init(dg.buf, dg.size, sc);
}
ok:
dcons_buf = dg.buf;
drv_init = 1;
return 0;
}
static int
dcons_attach_port(int port, char *name, int flags)
{
struct dcons_softc *dc;
struct tty *tp;
dc = &sc[port];
tp = tty_alloc(&dcons_ttydevsw, dc, NULL);
dc->flags = flags;
dc->tty = tp;
tty_makedev(tp, NULL, "%s", name);
return(0);
}
static int
dcons_attach(void)
{
int polltime;
dcons_attach_port(DCONS_CON, "dcons", 0);
dcons_attach_port(DCONS_GDB, "dgdb", DC_GDB);
callout_init(&dcons_callout, 0);
polltime = hz / poll_hz;
if (polltime < 1)
polltime = 1;
callout_reset(&dcons_callout, polltime, dcons_timeout, NULL);
return(0);
}
static int
dcons_detach(int port)
{
struct tty *tp;
struct dcons_softc *dc;
dc = &sc[port];
tp = dc->tty;
tty_lock(tp);
tty_rel_gone(tp);
return(0);
}
static int
dcons_modevent(module_t mode, int type, void *data)
{
int err = 0, ret;
switch (type) {
case MOD_LOAD:
ret = dcons_drv_init(1);
dcons_attach();
if (ret == 0) {
dcons_cnprobe(&dcons_consdev);
dcons_cninit(&dcons_consdev);
cnadd(&dcons_consdev);
}
break;
case MOD_UNLOAD:
printf("dcons: unload\n");
callout_stop(&dcons_callout);
cnremove(&dcons_consdev);
dcons_detach(DCONS_CON);
dcons_detach(DCONS_GDB);
dg.buf->magic = 0;
contigfree(dg.buf, DCONS_BUF_SIZE, M_DEVBUF);
break;
case MOD_SHUTDOWN:
#if 0 /* Keep connection after halt */
dg.buf->magic = 0;
#endif
break;
default:
err = EOPNOTSUPP;
break;
}
return(err);
}
#if defined(GDB)
/* Debugger interface */
static int
dcons_os_getc(struct dcons_softc *dc)
{
int c;
while ((c = dcons_os_checkc(dc)) == -1);
return (c & 0xff);
}
static int
dcons_dbg_probe(void)
{
int dcons_gdb;
if (getenv_int("dcons_gdb", &dcons_gdb) == 0)
return (-1);
return (dcons_gdb);
}
static void
dcons_dbg_init(void)
{
}
static void
dcons_dbg_term(void)
{
}
static void
dcons_dbg_putc(int c)
{
struct dcons_softc *dc = &sc[DCONS_GDB];
dcons_os_putc(dc, c);
}
static int
dcons_dbg_getc(void)
{
struct dcons_softc *dc = &sc[DCONS_GDB];
return (dcons_os_getc(dc));
}
#endif
DEV_MODULE(dcons, dcons_modevent, NULL);
MODULE_VERSION(dcons, DCONS_VERSION);