This provides a bootstrap and ongoing emergency console which is
intended to be available from very early during boot and at all times
thereafter, in contrast with alternatives such as UDP-based syslogd,
or logging in via ssh. The protocol is based on a simple shared-memory
ring buffer.
Signed-off-by: Ian Pratt <[email protected]>
Signed-off-by: Christian Limpach <[email protected]>
Signed-off-by: Chris Wright <[email protected]>
---
drivers/char/tty_io.c | 7
drivers/xen/Makefile | 1
drivers/xen/console/Makefile | 2
drivers/xen/console/console.c | 637 +++++++++++++++++++++++++++++++++++++
drivers/xen/console/xencons_ring.c | 141 ++++++++
include/xen/xencons.h | 14
6 files changed, 801 insertions(+), 1 deletion(-)
--- linus-2.6.orig/drivers/char/tty_io.c
+++ linus-2.6/drivers/char/tty_io.c
@@ -132,6 +132,8 @@ LIST_HEAD(tty_drivers); /* linked list
vt.c for deeply disgusting hack reasons */
DEFINE_MUTEX(tty_mutex);
+int console_use_vt = 1;
+
#ifdef CONFIG_UNIX98_PTYS
extern struct tty_driver *ptm_driver; /* Unix98 pty masters; for /dev/ptmx */
extern int pty_limit; /* Config limit on Unix98 ptys */
@@ -2060,7 +2062,7 @@ retry_open:
goto got_driver;
}
#ifdef CONFIG_VT
- if (device == MKDEV(TTY_MAJOR,0)) {
+ if (console_use_vt && (device == MKDEV(TTY_MAJOR,0))) {
extern struct tty_driver *console_driver;
driver = console_driver;
index = fg_console;
@@ -3258,6 +3260,8 @@ static int __init tty_init(void)
#endif
#ifdef CONFIG_VT
+ if (!console_use_vt)
+ goto out_vt;
cdev_init(&vc0_cdev, &console_fops);
if (cdev_add(&vc0_cdev, MKDEV(TTY_MAJOR, 0), 1) ||
register_chrdev_region(MKDEV(TTY_MAJOR, 0), 1, "/dev/vc/0") < 0)
@@ -3266,6 +3270,7 @@ static int __init tty_init(void)
class_device_create(tty_class, NULL, MKDEV(TTY_MAJOR, 0), NULL, "tty0");
vty_init();
+ out_vt:
#endif
return 0;
}
--- linus-2.6.orig/drivers/xen/Makefile
+++ linus-2.6/drivers/xen/Makefile
@@ -1,3 +1,4 @@
obj-y += core/
+obj-y += console/
--- /dev/null
+++ linus-2.6/drivers/xen/console/Makefile
@@ -0,0 +1,2 @@
+
+obj-y := console.o xencons_ring.o
--- /dev/null
+++ linus-2.6/drivers/xen/console/console.c
@@ -0,0 +1,637 @@
+/******************************************************************************
+ * console.c
+ *
+ * Virtual console driver.
+ *
+ * Copyright (c) 2002-2004, K A Fraser.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License version 2
+ * as published by the Free Software Foundation; or, when distributed
+ * separately from the Linux kernel or incorporated into other
+ * software packages, subject to the following license:
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this source file (the "Software"), to deal in the Software without
+ * restriction, including without limitation the rights to use, copy, modify,
+ * merge, publish, distribute, sublicense, and/or sell copies of the Software,
+ * and to permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+ * IN THE SOFTWARE.
+ */
+
+#include <linux/config.h>
+#include <linux/version.h>
+#include <linux/module.h>
+#include <linux/errno.h>
+#include <linux/signal.h>
+#include <linux/sched.h>
+#include <linux/interrupt.h>
+#include <linux/tty.h>
+#include <linux/tty_flip.h>
+#include <linux/serial.h>
+#include <linux/major.h>
+#include <linux/ptrace.h>
+#include <linux/ioport.h>
+#include <linux/mm.h>
+#include <linux/slab.h>
+#include <linux/init.h>
+#include <linux/console.h>
+#include <linux/bootmem.h>
+#include <linux/sysrq.h>
+#include <asm/io.h>
+#include <asm/irq.h>
+#include <asm/uaccess.h>
+#include <xen/interface/xen.h>
+#include <xen/interface/event_channel.h>
+#include <asm/hypervisor.h>
+#include <xen/evtchn.h>
+#include <xen/xencons.h>
+
+MODULE_LICENSE("Dual BSD/GPL");
+
+/*
+ * Modes:
+ * 'xencons=off' [XC_OFF]: Console is disabled.
+ * 'xencons=tty' [XC_TTY]: Console attached to '/dev/tty[0-9]+'.
+ * 'xencons=ttyS' [XC_SERIAL]: Console attached to '/dev/ttyS[0-9]+'.
+ * [XC_DEFAULT]: DOM0 -> XC_SERIAL ; all others -> XC_TTY.
+ *
+ * NB. In mode XC_TTY, we create dummy consoles for tty2-63. This suppresses
+ * warnings from standard distro startup scripts.
+ */
+static enum { XC_OFF, XC_DEFAULT, XC_TTY, XC_SERIAL } xc_mode = XC_DEFAULT;
+static int xc_num = -1;
+
+#ifdef CONFIG_MAGIC_SYSRQ
+static unsigned long sysrq_requested;
+extern int sysrq_enabled;
+#endif
+
+static int __init xencons_setup(char *str)
+{
+ char *q;
+ int n;
+
+ if (!strncmp(str, "ttyS", 4))
+ xc_mode = XC_SERIAL;
+ else if (!strncmp(str, "tty", 3))
+ xc_mode = XC_TTY;
+ else if (!strncmp(str, "off", 3))
+ xc_mode = XC_OFF;
+
+ switch (xc_mode) {
+ case XC_SERIAL:
+ n = simple_strtol(str+4, &q, 10);
+ if (q > (str + 4))
+ xc_num = n;
+ break;
+ case XC_TTY:
+ n = simple_strtol(str+3, &q, 10);
+ if (q > (str + 3))
+ xc_num = n;
+ break;
+ default:
+ break;
+ }
+
+ return 1;
+}
+__setup("xencons=", xencons_setup);
+
+/* The kernel and user-land drivers share a common transmit buffer. */
+static unsigned int wbuf_size = 4096;
+#define WBUF_MASK(_i) ((_i)&(wbuf_size-1))
+static char *wbuf;
+static unsigned int wc, wp; /* write_cons, write_prod */
+
+static int __init xencons_bufsz_setup(char *str)
+{
+ unsigned int goal;
+ goal = simple_strtoul(str, NULL, 0);
+ while (wbuf_size < goal)
+ wbuf_size <<= 1;
+ return 1;
+}
+__setup("xencons_bufsz=", xencons_bufsz_setup);
+
+/* This lock protects accesses to the common transmit buffer. */
+static spinlock_t xencons_lock = SPIN_LOCK_UNLOCKED;
+
+/* Common transmit-kick routine. */
+static void __xencons_tx_flush(void);
+
+static struct tty_driver *xencons_driver;
+
+/******************** Kernel console driver ********************************/
+
+static void kcons_write(
+ struct console *c, const char *s, unsigned int count)
+{
+ int i = 0;
+ unsigned long flags;
+
+ spin_lock_irqsave(&xencons_lock, flags);
+
+ while (i < count) {
+ for (; i < count; i++) {
+ if ((wp - wc) >= (wbuf_size - 1))
+ break;
+ if ((wbuf[WBUF_MASK(wp++)] = s[i]) == '\n')
+ wbuf[WBUF_MASK(wp++)] = '\r';
+ }
+
+ __xencons_tx_flush();
+ }
+
+ spin_unlock_irqrestore(&xencons_lock, flags);
+}
+
+static void kcons_write_dom0(
+ struct console *c, const char *s, unsigned int count)
+{
+ int rc;
+
+ while ((count > 0) &&
+ ((rc = HYPERVISOR_console_io(
+ CONSOLEIO_write, count, (char *)s)) > 0)) {
+ count -= rc;
+ s += rc;
+ }
+}
+
+static struct tty_driver *kcons_device(struct console *c, int *index)
+{
+ *index = 0;
+ return xencons_driver;
+}
+
+static struct console kcons_info = {
+ .device = kcons_device,
+ .flags = CON_PRINTBUFFER,
+ .index = -1,
+};
+
+static int __init xen_console_init(void)
+{
+ if (xen_init() < 0)
+ return 0;
+
+ if (xen_start_info->flags & SIF_INITDOMAIN) {
+ if (xc_mode == XC_DEFAULT)
+ xc_mode = XC_SERIAL;
+ kcons_info.write = kcons_write_dom0;
+ if (xc_mode == XC_SERIAL)
+ kcons_info.flags |= CON_ENABLED;
+ } else {
+ if (xc_mode == XC_DEFAULT)
+ xc_mode = XC_TTY;
+ kcons_info.write = kcons_write;
+ }
+
+ switch (xc_mode) {
+ case XC_SERIAL:
+ strcpy(kcons_info.name, "ttyS");
+ if (xc_num == -1)
+ xc_num = 0;
+ break;
+
+ case XC_TTY:
+ strcpy(kcons_info.name, "tty");
+ if (xc_num == -1)
+ xc_num = 1;
+ break;
+
+ default:
+ return 0;
+ }
+
+ wbuf = alloc_bootmem(wbuf_size);
+
+ register_console(&kcons_info);
+
+ return 0;
+}
+console_initcall(xen_console_init);
+
+/*** Useful function for console debugging -- goes straight to Xen. ***/
+asmlinkage int xprintk(const char *fmt, ...)
+{
+ va_list args;
+ int printk_len;
+ static char printk_buf[1024];
+
+ /* Emit the output into the temporary buffer */
+ va_start(args, fmt);
+ printk_len = vsnprintf(printk_buf, sizeof(printk_buf), fmt, args);
+ va_end(args);
+
+ /* Send the processed output directly to Xen. */
+ kcons_write_dom0(NULL, printk_buf, printk_len);
+
+ return 0;
+}
+
+/*** Forcibly flush console data before dying. ***/
+void xencons_force_flush(void)
+{
+ int sz;
+
+ /* Emergency console is synchronous, so there's nothing to flush. */
+ if (xen_start_info->flags & SIF_INITDOMAIN)
+ return;
+
+ /* Spin until console data is flushed through to the daemon. */
+ 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;
+ }
+}
+
+
+/******************** User-space console driver (/dev/console) ************/
+
+#define DRV(_d) (_d)
+#define TTY_INDEX(_tty) ((_tty)->index)
+
+static struct termios *xencons_termios[MAX_NR_CONSOLES];
+static struct termios *xencons_termios_locked[MAX_NR_CONSOLES];
+static struct tty_struct *xencons_tty;
+static int xencons_priv_irq;
+static char x_char;
+
+void xencons_rx(char *buf, unsigned len, struct pt_regs *regs)
+{
+ int i;
+ unsigned long flags;
+
+ spin_lock_irqsave(&xencons_lock, flags);
+ if (xencons_tty == NULL)
+ goto out;
+
+ for (i = 0; i < len; i++) {
+#ifdef CONFIG_MAGIC_SYSRQ
+ if (sysrq_enabled) {
+ if (buf[i] == '\x0f') { /* ^O */
+ sysrq_requested = jiffies;
+ continue; /* don't print the sysrq key */
+ } else if (sysrq_requested) {
+ unsigned long sysrq_timeout =
+ sysrq_requested + HZ*2;
+ sysrq_requested = 0;
+ if (time_before(jiffies, sysrq_timeout)) {
+ spin_unlock_irqrestore(
+ &xencons_lock, flags);
+ handle_sysrq(
+ buf[i], regs, xencons_tty);
+ spin_lock_irqsave(
+ &xencons_lock, flags);
+ continue;
+ }
+ }
+ }
+#endif
+ tty_insert_flip_char(xencons_tty, buf[i], 0);
+ }
+ tty_flip_buffer_push(xencons_tty);
+
+ out:
+ spin_unlock_irqrestore(&xencons_lock, flags);
+}
+
+static void __xencons_tx_flush(void)
+{
+ int sent, sz, work_done = 0;
+
+ if (x_char) {
+ if (xen_start_info->flags & SIF_INITDOMAIN)
+ kcons_write_dom0(NULL, &x_char, 1);
+ else
+ while (x_char)
+ if (xencons_ring_send(&x_char, 1) == 1)
+ break;
+ x_char = 0;
+ work_done = 1;
+ }
+
+ while (wc != wp) {
+ sz = wp - wc;
+ if (sz > (wbuf_size - WBUF_MASK(wc)))
+ sz = wbuf_size - WBUF_MASK(wc);
+ if (xen_start_info->flags & SIF_INITDOMAIN) {
+ kcons_write_dom0(NULL, &wbuf[WBUF_MASK(wc)], sz);
+ wc += sz;
+ } else {
+ sent = xencons_ring_send(&wbuf[WBUF_MASK(wc)], sz);
+ if (sent == 0)
+ break;
+ wc += sent;
+ }
+ work_done = 1;
+ }
+
+ if (work_done && (xencons_tty != NULL)) {
+ wake_up_interruptible(&xencons_tty->write_wait);
+ if ((xencons_tty->flags & (1 << TTY_DO_WRITE_WAKEUP)) &&
+ (xencons_tty->ldisc.write_wakeup != NULL))
+ (xencons_tty->ldisc.write_wakeup)(xencons_tty);
+ }
+}
+
+void xencons_tx(void)
+{
+ unsigned long flags;
+
+ spin_lock_irqsave(&xencons_lock, flags);
+ __xencons_tx_flush();
+ spin_unlock_irqrestore(&xencons_lock, flags);
+}
+
+/* Privileged receive callback and transmit kicker. */
+static irqreturn_t xencons_priv_interrupt(int irq, void *dev_id,
+ struct pt_regs *regs)
+{
+ static char rbuf[16];
+ int l;
+
+ while ((l = HYPERVISOR_console_io(CONSOLEIO_read, 16, rbuf)) > 0)
+ xencons_rx(rbuf, l, regs);
+
+ xencons_tx();
+
+ return IRQ_HANDLED;
+}
+
+static int xencons_write_room(struct tty_struct *tty)
+{
+ return wbuf_size - (wp - wc);
+}
+
+static int xencons_chars_in_buffer(struct tty_struct *tty)
+{
+ return wp - wc;
+}
+
+static void xencons_send_xchar(struct tty_struct *tty, char ch)
+{
+ unsigned long flags;
+
+ if (TTY_INDEX(tty) != 0)
+ return;
+
+ spin_lock_irqsave(&xencons_lock, flags);
+ x_char = ch;
+ __xencons_tx_flush();
+ spin_unlock_irqrestore(&xencons_lock, flags);
+}
+
+static void xencons_throttle(struct tty_struct *tty)
+{
+ if (TTY_INDEX(tty) != 0)
+ return;
+
+ if (I_IXOFF(tty))
+ xencons_send_xchar(tty, STOP_CHAR(tty));
+}
+
+static void xencons_unthrottle(struct tty_struct *tty)
+{
+ if (TTY_INDEX(tty) != 0)
+ return;
+
+ if (I_IXOFF(tty)) {
+ if (x_char != 0)
+ x_char = 0;
+ else
+ xencons_send_xchar(tty, START_CHAR(tty));
+ }
+}
+
+static void xencons_flush_buffer(struct tty_struct *tty)
+{
+ unsigned long flags;
+
+ if (TTY_INDEX(tty) != 0)
+ return;
+
+ spin_lock_irqsave(&xencons_lock, flags);
+ wc = wp = 0;
+ spin_unlock_irqrestore(&xencons_lock, flags);
+}
+
+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 int xencons_write(
+ struct tty_struct *tty,
+ const unsigned char *buf,
+ int count)
+{
+ int i;
+ unsigned long flags;
+
+ if (TTY_INDEX(tty) != 0)
+ return count;
+
+ spin_lock_irqsave(&xencons_lock, flags);
+
+ for (i = 0; i < count; i++)
+ if (!__xencons_put_char(buf[i]))
+ break;
+
+ if (i != 0)
+ __xencons_tx_flush();
+
+ spin_unlock_irqrestore(&xencons_lock, flags);
+
+ return i;
+}
+
+static void xencons_put_char(struct tty_struct *tty, u_char ch)
+{
+ unsigned long flags;
+
+ if (TTY_INDEX(tty) != 0)
+ return;
+
+ spin_lock_irqsave(&xencons_lock, flags);
+ (void)__xencons_put_char(ch);
+ spin_unlock_irqrestore(&xencons_lock, flags);
+}
+
+static void xencons_flush_chars(struct tty_struct *tty)
+{
+ unsigned long flags;
+
+ if (TTY_INDEX(tty) != 0)
+ return;
+
+ spin_lock_irqsave(&xencons_lock, flags);
+ __xencons_tx_flush();
+ spin_unlock_irqrestore(&xencons_lock, flags);
+}
+
+static void xencons_wait_until_sent(struct tty_struct *tty, int timeout)
+{
+ unsigned long orig_jiffies = jiffies;
+
+ if (TTY_INDEX(tty) != 0)
+ return;
+
+ while (DRV(tty->driver)->chars_in_buffer(tty)) {
+ set_current_state(TASK_INTERRUPTIBLE);
+ schedule_timeout(1);
+ if (signal_pending(current))
+ break;
+ if (timeout && time_after(jiffies, orig_jiffies + timeout))
+ break;
+ }
+
+ set_current_state(TASK_RUNNING);
+}
+
+static int xencons_open(struct tty_struct *tty, struct file *filp)
+{
+ unsigned long flags;
+
+ if (TTY_INDEX(tty) != 0)
+ return 0;
+
+ spin_lock_irqsave(&xencons_lock, flags);
+ tty->driver_data = NULL;
+ if (xencons_tty == NULL)
+ xencons_tty = tty;
+ __xencons_tx_flush();
+ spin_unlock_irqrestore(&xencons_lock, flags);
+
+ return 0;
+}
+
+static void xencons_close(struct tty_struct *tty, struct file *filp)
+{
+ unsigned long flags;
+
+ if (TTY_INDEX(tty) != 0)
+ return;
+
+ if (tty->count == 1) {
+ tty->closing = 1;
+ tty_wait_until_sent(tty, 0);
+ if (DRV(tty->driver)->flush_buffer != NULL)
+ DRV(tty->driver)->flush_buffer(tty);
+ if (tty->ldisc.flush_buffer != NULL)
+ tty->ldisc.flush_buffer(tty);
+ tty->closing = 0;
+ spin_lock_irqsave(&xencons_lock, flags);
+ xencons_tty = NULL;
+ spin_unlock_irqrestore(&xencons_lock, flags);
+ }
+}
+
+static struct tty_operations xencons_ops = {
+ .open = xencons_open,
+ .close = xencons_close,
+ .write = xencons_write,
+ .write_room = xencons_write_room,
+ .put_char = xencons_put_char,
+ .flush_chars = xencons_flush_chars,
+ .chars_in_buffer = xencons_chars_in_buffer,
+ .send_xchar = xencons_send_xchar,
+ .flush_buffer = xencons_flush_buffer,
+ .throttle = xencons_throttle,
+ .unthrottle = xencons_unthrottle,
+ .wait_until_sent = xencons_wait_until_sent,
+};
+
+static int __init xencons_init(void)
+{
+ int rc;
+
+ if (xen_init() < 0)
+ return -ENODEV;
+
+ if (xc_mode == XC_OFF)
+ return 0;
+
+ xencons_ring_init();
+
+ xencons_driver = alloc_tty_driver((xc_mode == XC_SERIAL) ?
+ 1 : MAX_NR_CONSOLES);
+ if (xencons_driver == NULL)
+ return -ENOMEM;
+
+ DRV(xencons_driver)->name = "xencons";
+ DRV(xencons_driver)->major = TTY_MAJOR;
+ DRV(xencons_driver)->type = TTY_DRIVER_TYPE_SERIAL;
+ DRV(xencons_driver)->subtype = SERIAL_TYPE_NORMAL;
+ DRV(xencons_driver)->init_termios = tty_std_termios;
+ DRV(xencons_driver)->flags =
+ TTY_DRIVER_REAL_RAW |
+ TTY_DRIVER_RESET_TERMIOS |
+ TTY_DRIVER_NO_DEVFS;
+ DRV(xencons_driver)->termios = xencons_termios;
+ DRV(xencons_driver)->termios_locked = xencons_termios_locked;
+
+ if (xc_mode == XC_SERIAL) {
+ DRV(xencons_driver)->name = "ttyS";
+ DRV(xencons_driver)->minor_start = 64 + xc_num;
+ DRV(xencons_driver)->name_base = 0 + xc_num;
+ } else {
+ DRV(xencons_driver)->name = "tty";
+ DRV(xencons_driver)->minor_start = xc_num;
+ DRV(xencons_driver)->name_base = xc_num;
+ }
+
+ tty_set_operations(xencons_driver, &xencons_ops);
+
+ if ((rc = tty_register_driver(DRV(xencons_driver))) != 0) {
+ printk("WARNING: Failed to register Xen virtual "
+ "console driver as '%s%d'\n",
+ DRV(xencons_driver)->name,
+ DRV(xencons_driver)->name_base);
+ put_tty_driver(xencons_driver);
+ xencons_driver = NULL;
+ return rc;
+ }
+
+ tty_register_device(xencons_driver, 0, NULL);
+
+ if (xen_start_info->flags & SIF_INITDOMAIN) {
+ xencons_priv_irq = bind_virq_to_irqhandler(
+ VIRQ_CONSOLE,
+ 0,
+ xencons_priv_interrupt,
+ 0,
+ "console",
+ NULL);
+ BUG_ON(xencons_priv_irq < 0);
+ }
+
+ printk("Xen virtual console successfully installed as %s%d\n",
+ DRV(xencons_driver)->name,
+ DRV(xencons_driver)->name_base );
+
+ return 0;
+}
+
+module_init(xencons_init);
--- /dev/null
+++ linus-2.6/drivers/xen/console/xencons_ring.c
@@ -0,0 +1,141 @@
+/*
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License version 2
+ * as published by the Free Software Foundation; or, when distributed
+ * separately from the Linux kernel or incorporated into other
+ * software packages, subject to the following license:
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this source file (the "Software"), to deal in the Software without
+ * restriction, including without limitation the rights to use, copy, modify,
+ * merge, publish, distribute, sublicense, and/or sell copies of the Software,
+ * and to permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+ * IN THE SOFTWARE.
+ */
+
+#include <linux/version.h>
+#include <linux/module.h>
+#include <linux/errno.h>
+#include <linux/signal.h>
+#include <linux/sched.h>
+#include <linux/interrupt.h>
+#include <linux/tty.h>
+#include <linux/tty_flip.h>
+#include <linux/serial.h>
+#include <linux/major.h>
+#include <linux/ptrace.h>
+#include <linux/ioport.h>
+#include <linux/mm.h>
+#include <linux/slab.h>
+
+#include <asm/hypervisor.h>
+#include <xen/evtchn.h>
+#include <xen/xencons.h>
+#include <linux/wait.h>
+#include <linux/interrupt.h>
+#include <linux/sched.h>
+#include <linux/err.h>
+#include <xen/interface/io/console.h>
+
+static int xencons_irq;
+
+static inline struct xencons_interface *xencons_interface(void)
+{
+ return mfn_to_virt(xen_start_info->console_mfn);
+}
+
+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_evtchn);
+}
+
+int xencons_ring_send(const char *data, unsigned len)
+{
+ int sent = 0;
+ struct xencons_interface *intf = xencons_interface();
+ XENCONS_RING_IDX cons, prod;
+
+ cons = intf->out_cons;
+ prod = intf->out_prod;
+ mb();
+ 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();
+ intf->out_prod = prod;
+
+ notify_daemon();
+
+ return sent;
+}
+
+static irqreturn_t handle_input(int irq, void *unused, struct pt_regs *regs)
+{
+ struct xencons_interface *intf = xencons_interface();
+ XENCONS_RING_IDX cons, prod;
+
+ cons = intf->in_cons;
+ prod = intf->in_prod;
+ mb();
+ BUG_ON((prod - cons) > sizeof(intf->in));
+
+ while (cons != prod) {
+ xencons_rx(intf->in+MASK_XENCONS_IDX(cons,intf->in), 1, regs);
+ cons++;
+ }
+
+ mb();
+ intf->in_cons = cons;
+
+ notify_daemon();
+
+ xencons_tx();
+
+ return IRQ_HANDLED;
+}
+
+int xencons_ring_init(void)
+{
+ int err;
+
+ if (xencons_irq)
+ unbind_from_irqhandler(xencons_irq, NULL);
+ xencons_irq = 0;
+
+ if (!xen_start_info->console_evtchn)
+ return 0;
+
+ err = bind_evtchn_to_irqhandler(
+ xen_start_info->console_evtchn,
+ handle_input, 0, "xencons", NULL);
+ if (err <= 0) {
+ printk(KERN_ERR "XEN console request irq failed %i\n", err);
+ return err;
+ }
+
+ xencons_irq = err;
+
+ /* In case we have in-flight data after save/restore... */
+ notify_daemon();
+
+ return 0;
+}
+
+void xencons_resume(void)
+{
+ (void)xencons_ring_init();
+}
--- /dev/null
+++ linus-2.6/include/xen/xencons.h
@@ -0,0 +1,14 @@
+#ifndef __ASM_XENCONS_H__
+#define __ASM_XENCONS_H__
+
+void xencons_force_flush(void);
+void xencons_resume(void);
+
+/* Interrupt work hooks. Receive data, or kick data out. */
+void xencons_rx(char *buf, unsigned len, struct pt_regs *regs);
+void xencons_tx(void);
+
+int xencons_ring_init(void);
+int xencons_ring_send(const char *data, unsigned len);
+
+#endif /* __ASM_XENCONS_H__ */
--
> --- linus-2.6.orig/drivers/char/tty_io.c
> +++ linus-2.6/drivers/char/tty_io.c
> @@ -132,6 +132,8 @@ LIST_HEAD(tty_drivers); /* linked list
> vt.c for deeply disgusting hack reasons */
> DEFINE_MUTEX(tty_mutex);
>
> +int console_use_vt = 1;
> +
Can you explain why this variable is needed? It shouldn't. If you only
register your console as the primary console nothing else should
be printed.
> +/*** Useful function for console debugging -- goes straight to Xen. ***/
> +asmlinkage int xprintk(const char *fmt, ...)
This is called early_printk in the rest of i386. Please use that name too.
-Andi
On Tue, May 09, 2006 at 03:26:10PM +0200, Andi Kleen wrote:
>
> > --- linus-2.6.orig/drivers/char/tty_io.c
> > +++ linus-2.6/drivers/char/tty_io.c
> > @@ -132,6 +132,8 @@ LIST_HEAD(tty_drivers); /* linked list
> > vt.c for deeply disgusting hack reasons */
> > DEFINE_MUTEX(tty_mutex);
> >
> > +int console_use_vt = 1;
> > +
>
> Can you explain why this variable is needed? It shouldn't. If you only
> register your console as the primary console nothing else should
> be printed.
It is needed for having a kernel which can run both as a dom0 and domU
kernel. For dom0, you want to build with CONFIG_VT enabled while for
domU, the CONFIG_VT code doesn't let the xen console be the primary
console unless you specify it on the command line.
I've removed this from the patchqueue since a kernel built from the
patchqueue won't run as a dom0 kernel anyway.
> > +/*** Useful function for console debugging -- goes straight to Xen. ***/
> > +asmlinkage int xprintk(const char *fmt, ...)
>
> This is called early_printk in the rest of i386. Please use that name too.
We have proper early_printk support but it's not part of the patchqueue.
This is more of a debug function where you would rename the kernel/printk
to something else and rename this to printk. I've removed it.
christian
On Tue, 09 May 2006 00:00:29 -0700
Chris Wright <[email protected]> wrote:
> This provides a bootstrap and ongoing emergency console which is
> intended to be available from very early during boot and at all times
> thereafter, in contrast with alternatives such as UDP-based syslogd,
> or logging in via ssh. The protocol is based on a simple shared-memory
> ring buffer.
>
> ...
>
> +/* The kernel and user-land drivers share a common transmit buffer. */
> +static unsigned int wbuf_size = 4096;
> +#define WBUF_MASK(_i) ((_i)&(wbuf_size-1))
> +static char *wbuf;
> +static unsigned int wc, wp; /* write_cons, write_prod */
> +
> +static int __init xencons_bufsz_setup(char *str)
> +{
> + unsigned int goal;
> + goal = simple_strtoul(str, NULL, 0);
> + while (wbuf_size < goal)
> + wbuf_size <<= 1;
roundup_pow_of_two()
> +/* This lock protects accesses to the common transmit buffer. */
> +static spinlock_t xencons_lock = SPIN_LOCK_UNLOCKED;
DEFINE_SPINLOCK() (entire patchset)
> +
> +static void kcons_write(
> + struct console *c, const char *s, unsigned int count)
> +{
> + int i = 0;
> + unsigned long flags;
> +
> + spin_lock_irqsave(&xencons_lock, flags);
> +
> + while (i < count) {
> + for (; i < count; i++) {
> + if ((wp - wc) >= (wbuf_size - 1))
> + break;
> + if ((wbuf[WBUF_MASK(wp++)] = s[i]) == '\n')
> + wbuf[WBUF_MASK(wp++)] = '\r';
> + }
> +
> + __xencons_tx_flush();
> + }
> +
> + spin_unlock_irqrestore(&xencons_lock, flags);
> +}
hm. You have all that elaborate generate-ringbuffer-code-with-C-macros
stuff in the header file patch, yet this code (blessedly) doesn't use it.
> +static void kcons_write_dom0(
> + struct console *c, const char *s, unsigned int count)
> +{
> + int rc;
> +
> + while ((count > 0) &&
> + ((rc = HYPERVISOR_console_io(
> + CONSOLEIO_write, count, (char *)s)) > 0)) {
> + count -= rc;
> + s += rc;
> + }
> +}
must.. not.. mention.. coding.. style..
Andrew Morton wrote:
>>+static void kcons_write_dom0(
>>+ struct console *c, const char *s, unsigned int count)
>>+{
>>+ int rc;
>>+
>>+ while ((count > 0) &&
>>+ ((rc = HYPERVISOR_console_io(
>>+ CONSOLEIO_write, count, (char *)s)) > 0)) {
>>+ count -= rc;
>>+ s += rc;
>>+ }
>>+}
>
>
> must.. not.. mention.. coding.. style..
Someone should write you a script to go through a patch and flag the
most common style mistakes. Have the output formatted to look like
you're replying to the mail, and wire it up to your inbox ;)
--
SUSE Labs, Novell Inc.
Send instant messages to your online friends http://au.messenger.yahoo.com
Nick Piggin <[email protected]> wrote:
>
> Andrew Morton wrote:
>
> >>+static void kcons_write_dom0(
> >>+ struct console *c, const char *s, unsigned int count)
> >>+{
> >>+ int rc;
> >>+
> >>+ while ((count > 0) &&
> >>+ ((rc = HYPERVISOR_console_io(
> >>+ CONSOLEIO_write, count, (char *)s)) > 0)) {
> >>+ count -= rc;
> >>+ s += rc;
> >>+ }
> >>+}
> >
> >
> > must.. not.. mention.. coding.. style..
>
> Someone should write you a script to go through a patch and flag the
> most common style mistakes. Have the output formatted to look like
> you're replying to the mail, and wire it up to your inbox ;)
>
Even better, someone should write a coding style document, so people get it
right from the outset.
Clever, aren't I?
Andrew Morton wrote:
> Nick Piggin <[email protected]> wrote:
>
>>Someone should write you a script to go through a patch and flag the
>>most common style mistakes. Have the output formatted to look like
>>you're replying to the mail, and wire it up to your inbox ;)
>>
>
>
> Even better, someone should write a coding style document, so people get it
> right from the outset.
I thought that was tried several years back -- I noticed you still
do it manually, so I just assumed that the style document scheme
hadn't worked.
>
> Clever, aren't I?
>
Yes... but I don't think it's your cleverness that's the problem ;)
--
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