diff options
Diffstat (limited to 'drivers/tty/hvc/hvc_console.c')
| -rw-r--r-- | drivers/tty/hvc/hvc_console.c | 326 |
1 files changed, 193 insertions, 133 deletions
diff --git a/drivers/tty/hvc/hvc_console.c b/drivers/tty/hvc/hvc_console.c index a8d399188242..6b58f340f210 100644 --- a/drivers/tty/hvc/hvc_console.c +++ b/drivers/tty/hvc/hvc_console.c @@ -1,3 +1,4 @@ +// SPDX-License-Identifier: GPL-2.0+ /* * Copyright (C) 2001 Anton Blanchard <anton@au.ibm.com>, IBM * Copyright (C) 2001 Paul Mackerras <paulus@au.ibm.com>, IBM @@ -6,20 +7,6 @@ * * Additional Author(s): * Ryan S. Arnold <rsa@us.ibm.com> - * - * 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> @@ -62,7 +49,7 @@ #define N_OUTBUF 16 #define N_INBUF 16 -#define __ALIGNED__ __attribute__((__aligned__(sizeof(long)))) +#define __ALIGNED__ __attribute__((__aligned__(L1_CACHE_BYTES))) static struct tty_driver *hvc_driver; static struct task_struct *hvc_task; @@ -86,7 +73,7 @@ static LIST_HEAD(hvc_structs); * Protect the list of hvc_struct instances from inserts and removals during * list traversal. */ -static DEFINE_SPINLOCK(hvc_structs_lock); +static DEFINE_MUTEX(hvc_structs_mutex); /* * This value is used to assign a tty->index value to a hvc_struct based @@ -96,7 +83,7 @@ static DEFINE_SPINLOCK(hvc_structs_lock); static int last_hvc = -1; /* - * Do not call this function with either the hvc_structs_lock or the hvc_struct + * Do not call this function with either the hvc_structs_mutex or the hvc_struct * lock held. If successful, this function increments the kref reference * count against the target hvc_struct so it should be released when finished. */ @@ -105,24 +92,46 @@ static struct hvc_struct *hvc_get_by_index(int index) struct hvc_struct *hp; unsigned long flags; - spin_lock(&hvc_structs_lock); + mutex_lock(&hvc_structs_mutex); list_for_each_entry(hp, &hvc_structs, next) { spin_lock_irqsave(&hp->lock, flags); if (hp->index == index) { tty_port_get(&hp->port); spin_unlock_irqrestore(&hp->lock, flags); - spin_unlock(&hvc_structs_lock); + mutex_unlock(&hvc_structs_mutex); return hp; } spin_unlock_irqrestore(&hp->lock, flags); } hp = NULL; + mutex_unlock(&hvc_structs_mutex); - spin_unlock(&hvc_structs_lock); return hp; } +static int __hvc_flush(const struct hv_ops *ops, uint32_t vtermno, bool wait) +{ + if (wait) + might_sleep(); + + if (ops->flush) + return ops->flush(vtermno, wait); + return 0; +} + +static int hvc_console_flush(const struct hv_ops *ops, uint32_t vtermno) +{ + return __hvc_flush(ops, vtermno, false); +} + +/* + * Wait for the console to flush before writing more to it. This sleeps. + */ +static int hvc_flush(struct hvc_struct *hp) +{ + return __hvc_flush(hp->ops, hp->vtermno, true); +} /* * Initial console vtermnos for console API usage prior to full console @@ -169,15 +178,20 @@ static void hvc_console_print(struct console *co, const char *b, if (r <= 0) { /* throw away characters on error * but spin in case of -EAGAIN */ - if (r != -EAGAIN) + if (r != -EAGAIN) { i = 0; - } else if (r > 0) { + } else { + hvc_console_flush(cons_ops[index], + vtermnos[index]); + } + } else { i -= r; if (i > 0) memmove(c, c+r, i); } } } + hvc_console_flush(cons_ops[index], vtermnos[index]); } static struct tty_driver *hvc_console_device(struct console *c, int *index) @@ -237,21 +251,21 @@ static void hvc_port_destruct(struct tty_port *port) struct hvc_struct *hp = container_of(port, struct hvc_struct, port); unsigned long flags; - spin_lock(&hvc_structs_lock); + mutex_lock(&hvc_structs_mutex); spin_lock_irqsave(&hp->lock, flags); list_del(&(hp->next)); spin_unlock_irqrestore(&hp->lock, flags); - spin_unlock(&hvc_structs_lock); + mutex_unlock(&hvc_structs_mutex); kfree(hp); } static void hvc_check_console(int index) { - /* Already enabled, bail out */ - if (hvc_console.flags & CON_ENABLED) + /* Already registered, bail out */ + if (console_is_registered(&hvc_console)) return; /* If this index is what the user requested, then register @@ -278,7 +292,7 @@ int hvc_instantiate(uint32_t vtermno, int index, const struct hv_ops *ops) if (vtermnos[index] != -1) return -1; - /* make sure no no tty has been registered in this index */ + /* make sure no tty has been registered in this index */ hp = hvc_get_by_index(index); if (hp) { tty_port_put(&hp->port); @@ -288,10 +302,6 @@ int hvc_instantiate(uint32_t vtermno, int index, const struct hv_ops *ops) vtermnos[index] = vtermno; cons_ops[index] = ops; - /* reserve all indices up to and including this index */ - if (last_hvc < index) - last_hvc = index; - /* check if we need to re-register the kernel console */ hvc_check_console(index); @@ -361,15 +371,14 @@ static int hvc_open(struct tty_struct *tty, struct file * filp) * tty fields and return the kref reference. */ if (rc) { - tty_port_tty_set(&hp->port, NULL); - tty->driver_data = NULL; - tty_port_put(&hp->port); printk(KERN_ERR "hvc_open: request_irq failed with rc %d.\n", rc); - } else + } else { /* We are ready... raise DTR/RTS */ if (C_BAUD(tty)) if (hp->ops->dtr_rts) - hp->ops->dtr_rts(hp, 1); + hp->ops->dtr_rts(hp, true); + tty_port_set_initialized(&hp->port, true); + } /* Force wakeup of the polling thread */ hvc_kick(); @@ -379,22 +388,12 @@ static int hvc_open(struct tty_struct *tty, struct file * filp) static void hvc_close(struct tty_struct *tty, struct file * filp) { - struct hvc_struct *hp; + struct hvc_struct *hp = tty->driver_data; unsigned long flags; if (tty_hung_up_p(filp)) return; - /* - * No driver_data means that this close was issued after a failed - * hvc_open by the tty layer's release_dev() function and we can just - * exit cleanly because the kref reference wasn't made. - */ - if (!tty->driver_data) - return; - - hp = tty->driver_data; - spin_lock_irqsave(&hp->port.lock, flags); if (--hp->port.count == 0) { @@ -402,9 +401,12 @@ static void hvc_close(struct tty_struct *tty, struct file * filp) /* We are done with the tty pointer now. */ tty_port_tty_set(&hp->port, NULL); + if (!tty_port_initialized(&hp->port)) + return; + if (C_HUPCL(tty)) if (hp->ops->dtr_rts) - hp->ops->dtr_rts(hp, 0); + hp->ops->dtr_rts(hp, false); if (hp->ops->notifier_del) hp->ops->notifier_del(hp, hp->data); @@ -418,6 +420,7 @@ static void hvc_close(struct tty_struct *tty, struct file * filp) * waking periodically to check chars_in_buffer(). */ tty_wait_until_sent(tty, HVC_CLOSE_WAIT); + tty_port_set_initialized(&hp->port, false); } else { if (hp->port.count < 0) printk(KERN_ERR "hvc_close %X: oops, count is %d\n", @@ -493,11 +496,11 @@ static int hvc_push(struct hvc_struct *hp) return n; } -static int hvc_write(struct tty_struct *tty, const unsigned char *buf, int count) +static ssize_t hvc_write(struct tty_struct *tty, const u8 *buf, size_t count) { struct hvc_struct *hp = tty->driver_data; unsigned long flags; - int rsize, written = 0; + size_t rsize, written = 0; /* This write was probably executed during a tty close. */ if (!hp) @@ -507,29 +510,43 @@ static int hvc_write(struct tty_struct *tty, const unsigned char *buf, int count if (hp->port.count <= 0) return -EIO; - spin_lock_irqsave(&hp->lock, flags); + while (count > 0) { + int ret = 0; - /* Push pending writes */ - if (hp->n_outbuf > 0) - hvc_push(hp); - - while (count > 0 && (rsize = hp->outbuf_size - hp->n_outbuf) > 0) { - if (rsize > count) - rsize = count; - memcpy(hp->outbuf + hp->n_outbuf, buf, rsize); - count -= rsize; - buf += rsize; - hp->n_outbuf += rsize; - written += rsize; - hvc_push(hp); + spin_lock_irqsave(&hp->lock, flags); + + rsize = hp->outbuf_size - hp->n_outbuf; + + if (rsize) { + if (rsize > count) + rsize = count; + memcpy(hp->outbuf + hp->n_outbuf, buf, rsize); + count -= rsize; + buf += rsize; + hp->n_outbuf += rsize; + written += rsize; + } + + if (hp->n_outbuf > 0) + ret = hvc_push(hp); + + spin_unlock_irqrestore(&hp->lock, flags); + + if (!ret) + break; + + if (count) { + if (hp->n_outbuf > 0) + hvc_flush(hp); + cond_resched(); + } } - spin_unlock_irqrestore(&hp->lock, flags); /* - * Racy, but harmless, kick thread if there is still pending data. + * Kick thread to flush if there's still pending data + * or to wakeup the write queue. */ - if (hp->n_outbuf) - hvc_kick(); + hvc_kick(); return written; } @@ -569,7 +586,7 @@ static void hvc_set_winsz(struct work_struct *work) * how much write room the driver can guarantee will be sent OR BUFFERED. This * driver MUST honor the return value. */ -static int hvc_write_room(struct tty_struct *tty) +static unsigned int hvc_write_room(struct tty_struct *tty) { struct hvc_struct *hp = tty->driver_data; @@ -579,7 +596,7 @@ static int hvc_write_room(struct tty_struct *tty) return hp->outbuf_size - hp->n_outbuf; } -static int hvc_chars_in_buffer(struct tty_struct *tty) +static unsigned int hvc_chars_in_buffer(struct tty_struct *tty) { struct hvc_struct *hp = tty->driver_data; @@ -600,13 +617,22 @@ static int hvc_chars_in_buffer(struct tty_struct *tty) #define MAX_TIMEOUT (2000) static u32 timeout = MIN_TIMEOUT; +/* + * Maximum number of bytes to get from the console driver if hvc_poll is + * called from driver (and can't sleep). Any more than this and we break + * and start polling with khvcd. This value was derived from an OpenBMC + * console with the OPAL driver that results in about 0.25ms interrupts off + * latency. + */ +#define HVC_ATOMIC_READ_MAX 128 + #define HVC_POLL_READ 0x00000001 #define HVC_POLL_WRITE 0x00000002 -int hvc_poll(struct hvc_struct *hp) +static int __hvc_poll(struct hvc_struct *hp, bool may_sleep) { struct tty_struct *tty; - int i, n, poll_mask = 0; + int i, n, count, poll_mask = 0; char buf[N_INBUF] __ALIGNED__; unsigned long flags; int read_total = 0; @@ -625,6 +651,12 @@ int hvc_poll(struct hvc_struct *hp) timeout = (written_total) ? 0 : MIN_TIMEOUT; } + if (may_sleep) { + spin_unlock_irqrestore(&hp->lock, flags); + cond_resched(); + spin_lock_irqsave(&hp->lock, flags); + } + /* No tty attached, just skip */ tty = tty_port_tty_get(&hp->port); if (tty == NULL) @@ -632,7 +664,7 @@ int hvc_poll(struct hvc_struct *hp) /* Now check if we can get data (are we throttled ?) */ if (tty_throttled(tty)) - goto throttled; + goto out; /* If we aren't notifier driven and aren't throttled, we always * request a reschedule @@ -640,57 +672,73 @@ int hvc_poll(struct hvc_struct *hp) if (!hp->irq_requested) poll_mask |= HVC_POLL_READ; + read_again: /* Read data if any */ - for (;;) { - int count = tty_buffer_request_room(&hp->port, N_INBUF); + count = tty_buffer_request_room(&hp->port, N_INBUF); + + /* If flip is full, just reschedule a later read */ + if (count == 0) { + poll_mask |= HVC_POLL_READ; + goto out; + } - /* If flip is full, just reschedule a later read */ - if (count == 0) { + n = hp->ops->get_chars(hp->vtermno, buf, count); + if (n <= 0) { + /* Hangup the tty when disconnected from host */ + if (n == -EPIPE) { + spin_unlock_irqrestore(&hp->lock, flags); + tty_hangup(tty); + spin_lock_irqsave(&hp->lock, flags); + } else if ( n == -EAGAIN ) { + /* + * Some back-ends can only ensure a certain min + * num of bytes read, which may be > 'count'. + * Let the tty clear the flip buff to make room. + */ poll_mask |= HVC_POLL_READ; - break; } + goto out; + } - n = hp->ops->get_chars(hp->vtermno, buf, count); - if (n <= 0) { - /* Hangup the tty when disconnected from host */ - if (n == -EPIPE) { - spin_unlock_irqrestore(&hp->lock, flags); - tty_hangup(tty); - spin_lock_irqsave(&hp->lock, flags); - } else if ( n == -EAGAIN ) { - /* - * Some back-ends can only ensure a certain min - * num of bytes read, which may be > 'count'. - * Let the tty clear the flip buff to make room. - */ - poll_mask |= HVC_POLL_READ; - } - break; - } - for (i = 0; i < n; ++i) { + for (i = 0; i < n; ++i) { #ifdef CONFIG_MAGIC_SYSRQ - if (hp->index == hvc_console.index) { - /* Handle the SysRq Hack */ - /* XXX should support a sequence */ - if (buf[i] == '\x0f') { /* ^O */ - /* if ^O is pressed again, reset - * sysrq_pressed and flip ^O char */ - sysrq_pressed = !sysrq_pressed; - if (sysrq_pressed) - continue; - } else if (sysrq_pressed) { - handle_sysrq(buf[i]); - sysrq_pressed = 0; + if (hp->index == hvc_console.index) { + /* Handle the SysRq Hack */ + /* XXX should support a sequence */ + if (buf[i] == '\x0f') { /* ^O */ + /* if ^O is pressed again, reset + * sysrq_pressed and flip ^O char */ + sysrq_pressed = !sysrq_pressed; + if (sysrq_pressed) continue; - } + } else if (sysrq_pressed) { + handle_sysrq(buf[i]); + sysrq_pressed = 0; + continue; } -#endif /* CONFIG_MAGIC_SYSRQ */ - tty_insert_flip_char(&hp->port, buf[i], 0); } +#endif /* CONFIG_MAGIC_SYSRQ */ + tty_insert_flip_char(&hp->port, buf[i], 0); + } + read_total += n; - read_total += n; + if (may_sleep) { + /* Keep going until the flip is full */ + spin_unlock_irqrestore(&hp->lock, flags); + cond_resched(); + spin_lock_irqsave(&hp->lock, flags); + goto read_again; + } else if (read_total < HVC_ATOMIC_READ_MAX) { + /* Break and defer if it's a large read in atomic */ + goto read_again; } - throttled: + + /* + * Latency break, schedule another poll immediately. + */ + poll_mask |= HVC_POLL_READ; + + out: /* Wakeup write queue if necessary */ if (hp->do_wakeup) { hp->do_wakeup = 0; @@ -710,6 +758,11 @@ int hvc_poll(struct hvc_struct *hp) return poll_mask; } + +int hvc_poll(struct hvc_struct *hp) +{ + return __hvc_poll(hp, false); +} EXPORT_SYMBOL_GPL(hvc_poll); /** @@ -746,11 +799,12 @@ static int khvcd(void *unused) try_to_freeze(); wmb(); if (!cpus_are_in_xmon()) { - spin_lock(&hvc_structs_lock); + mutex_lock(&hvc_structs_mutex); list_for_each_entry(hp, &hvc_structs, next) { - poll_mask |= hvc_poll(hp); + poll_mask |= __hvc_poll(hp, true); + cond_resched(); } - spin_unlock(&hvc_structs_lock); + mutex_unlock(&hvc_structs_mutex); } else poll_mask |= HVC_POLL_READ; if (hvc_kicked) @@ -868,8 +922,7 @@ struct hvc_struct *hvc_alloc(uint32_t vtermno, int data, return ERR_PTR(err); } - hp = kzalloc(ALIGN(sizeof(*hp), sizeof(long)) + outbuf_size, - GFP_KERNEL); + hp = kzalloc(struct_size(hp, outbuf, outbuf_size), GFP_KERNEL); if (!hp) return ERR_PTR(-ENOMEM); @@ -877,14 +930,13 @@ struct hvc_struct *hvc_alloc(uint32_t vtermno, int data, hp->data = data; hp->ops = ops; hp->outbuf_size = outbuf_size; - hp->outbuf = &((char *)hp)[ALIGN(sizeof(*hp), sizeof(long))]; tty_port_init(&hp->port); hp->port.ops = &hvc_port_ops; INIT_WORK(&hp->tty_resize, hvc_set_winsz); spin_lock_init(&hp->lock); - spin_lock(&hvc_structs_lock); + mutex_lock(&hvc_structs_mutex); /* * find index to use: @@ -895,16 +947,25 @@ struct hvc_struct *hvc_alloc(uint32_t vtermno, int data, cons_ops[i] == hp->ops) break; - /* no matching slot, just use a counter */ - if (i >= MAX_NR_HVC_CONSOLES) - i = ++last_hvc; + if (i >= MAX_NR_HVC_CONSOLES) { + + /* find 'empty' slot for console */ + for (i = 0; i < MAX_NR_HVC_CONSOLES && vtermnos[i] != -1; i++) { + } + + /* no matching slot, just use a counter */ + if (i == MAX_NR_HVC_CONSOLES) + i = ++last_hvc + MAX_NR_HVC_CONSOLES; + } hp->index = i; - cons_ops[i] = ops; - vtermnos[i] = vtermno; + if (i < MAX_NR_HVC_CONSOLES) { + cons_ops[i] = ops; + vtermnos[i] = vtermno; + } list_add_tail(&(hp->next), &hvc_structs); - spin_unlock(&hvc_structs_lock); + mutex_unlock(&hvc_structs_mutex); /* check if we need to re-register the kernel console */ hvc_check_console(i); @@ -913,7 +974,7 @@ struct hvc_struct *hvc_alloc(uint32_t vtermno, int data, } EXPORT_SYMBOL_GPL(hvc_alloc); -int hvc_remove(struct hvc_struct *hp) +void hvc_remove(struct hvc_struct *hp) { unsigned long flags; struct tty_struct *tty; @@ -947,7 +1008,6 @@ int hvc_remove(struct hvc_struct *hp) tty_vhangup(tty); tty_kref_put(tty); } - return 0; } EXPORT_SYMBOL_GPL(hvc_remove); @@ -958,9 +1018,10 @@ static int hvc_init(void) int err; /* We need more than hvc_count adapters due to hotplug additions. */ - drv = alloc_tty_driver(HVC_ALLOC_TTY_ADAPTERS); - if (!drv) { - err = -ENOMEM; + drv = tty_alloc_driver(HVC_ALLOC_TTY_ADAPTERS, TTY_DRIVER_REAL_RAW | + TTY_DRIVER_RESET_TERMIOS); + if (IS_ERR(drv)) { + err = PTR_ERR(drv); goto out; } @@ -970,7 +1031,6 @@ static int hvc_init(void) drv->minor_start = HVC_MINOR; drv->type = TTY_DRIVER_TYPE_SYSTEM; drv->init_termios = tty_std_termios; - drv->flags = TTY_DRIVER_REAL_RAW | TTY_DRIVER_RESET_TERMIOS; tty_set_operations(drv, &hvc_ops); /* Always start the kthread because there can be hotplug vty adapters @@ -1000,7 +1060,7 @@ stop_thread: kthread_stop(hvc_task); hvc_task = NULL; put_tty: - put_tty_driver(drv); + tty_driver_kref_put(drv); out: return err; } |