forked from Qortal/Brooklyn
You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
1069 lines
25 KiB
1069 lines
25 KiB
// SPDX-License-Identifier: GPL-2.0+ |
|
/* |
|
* Copyright (C) 2001 Anton Blanchard <[email protected]>, IBM |
|
* Copyright (C) 2001 Paul Mackerras <[email protected]>, IBM |
|
* Copyright (C) 2004 Benjamin Herrenschmidt <[email protected]>, IBM Corp. |
|
* Copyright (C) 2004 IBM Corporation |
|
* |
|
* Additional Author(s): |
|
* Ryan S. Arnold <[email protected]> |
|
*/ |
|
|
|
#include <linux/console.h> |
|
#include <linux/cpumask.h> |
|
#include <linux/init.h> |
|
#include <linux/kbd_kern.h> |
|
#include <linux/kernel.h> |
|
#include <linux/kthread.h> |
|
#include <linux/list.h> |
|
#include <linux/major.h> |
|
#include <linux/atomic.h> |
|
#include <linux/sysrq.h> |
|
#include <linux/tty.h> |
|
#include <linux/tty_flip.h> |
|
#include <linux/sched.h> |
|
#include <linux/spinlock.h> |
|
#include <linux/delay.h> |
|
#include <linux/freezer.h> |
|
#include <linux/slab.h> |
|
#include <linux/serial_core.h> |
|
|
|
#include <linux/uaccess.h> |
|
|
|
#include "hvc_console.h" |
|
|
|
#define HVC_MAJOR 229 |
|
#define HVC_MINOR 0 |
|
|
|
/* |
|
* Wait this long per iteration while trying to push buffered data to the |
|
* hypervisor before allowing the tty to complete a close operation. |
|
*/ |
|
#define HVC_CLOSE_WAIT (HZ/100) /* 1/10 of a second */ |
|
|
|
/* |
|
* These sizes are most efficient for vio, because they are the |
|
* native transfer size. We could make them selectable in the |
|
* future to better deal with backends that want other buffer sizes. |
|
*/ |
|
#define N_OUTBUF 16 |
|
#define N_INBUF 16 |
|
|
|
#define __ALIGNED__ __attribute__((__aligned__(sizeof(long)))) |
|
|
|
static struct tty_driver *hvc_driver; |
|
static struct task_struct *hvc_task; |
|
|
|
/* Picks up late kicks after list walk but before schedule() */ |
|
static int hvc_kicked; |
|
|
|
/* hvc_init is triggered from hvc_alloc, i.e. only when actually used */ |
|
static atomic_t hvc_needs_init __read_mostly = ATOMIC_INIT(-1); |
|
|
|
static int hvc_init(void); |
|
|
|
#ifdef CONFIG_MAGIC_SYSRQ |
|
static int sysrq_pressed; |
|
#endif |
|
|
|
/* dynamic list of hvc_struct instances */ |
|
static LIST_HEAD(hvc_structs); |
|
|
|
/* |
|
* Protect the list of hvc_struct instances from inserts and removals during |
|
* list traversal. |
|
*/ |
|
static DEFINE_MUTEX(hvc_structs_mutex); |
|
|
|
/* |
|
* This value is used to assign a tty->index value to a hvc_struct based |
|
* upon order of exposure via hvc_probe(), when we can not match it to |
|
* a console candidate registered with hvc_instantiate(). |
|
*/ |
|
static int last_hvc = -1; |
|
|
|
/* |
|
* 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. |
|
*/ |
|
static struct hvc_struct *hvc_get_by_index(int index) |
|
{ |
|
struct hvc_struct *hp; |
|
unsigned long flags; |
|
|
|
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); |
|
mutex_unlock(&hvc_structs_mutex); |
|
return hp; |
|
} |
|
spin_unlock_irqrestore(&hp->lock, flags); |
|
} |
|
hp = NULL; |
|
mutex_unlock(&hvc_structs_mutex); |
|
|
|
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 |
|
* initialization. Any vty adapter outside this range will not have usable |
|
* console interfaces but can still be used as a tty device. This has to be |
|
* static because kmalloc will not work during early console init. |
|
*/ |
|
static const struct hv_ops *cons_ops[MAX_NR_HVC_CONSOLES]; |
|
static uint32_t vtermnos[MAX_NR_HVC_CONSOLES] = |
|
{[0 ... MAX_NR_HVC_CONSOLES - 1] = -1}; |
|
|
|
/* |
|
* Console APIs, NOT TTY. These APIs are available immediately when |
|
* hvc_console_setup() finds adapters. |
|
*/ |
|
|
|
static void hvc_console_print(struct console *co, const char *b, |
|
unsigned count) |
|
{ |
|
char c[N_OUTBUF] __ALIGNED__; |
|
unsigned i = 0, n = 0; |
|
int r, donecr = 0, index = co->index; |
|
|
|
/* Console access attempt outside of acceptable console range. */ |
|
if (index >= MAX_NR_HVC_CONSOLES) |
|
return; |
|
|
|
/* This console adapter was removed so it is not usable. */ |
|
if (vtermnos[index] == -1) |
|
return; |
|
|
|
while (count > 0 || i > 0) { |
|
if (count > 0 && i < sizeof(c)) { |
|
if (b[n] == '\n' && !donecr) { |
|
c[i++] = '\r'; |
|
donecr = 1; |
|
} else { |
|
c[i++] = b[n++]; |
|
donecr = 0; |
|
--count; |
|
} |
|
} else { |
|
r = cons_ops[index]->put_chars(vtermnos[index], c, i); |
|
if (r <= 0) { |
|
/* throw away characters on error |
|
* but spin in case of -EAGAIN */ |
|
if (r != -EAGAIN) { |
|
i = 0; |
|
} else { |
|
hvc_console_flush(cons_ops[index], |
|
vtermnos[index]); |
|
} |
|
} else if (r > 0) { |
|
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) |
|
{ |
|
if (vtermnos[c->index] == -1) |
|
return NULL; |
|
|
|
*index = c->index; |
|
return hvc_driver; |
|
} |
|
|
|
static int hvc_console_setup(struct console *co, char *options) |
|
{ |
|
if (co->index < 0 || co->index >= MAX_NR_HVC_CONSOLES) |
|
return -ENODEV; |
|
|
|
if (vtermnos[co->index] == -1) |
|
return -ENODEV; |
|
|
|
return 0; |
|
} |
|
|
|
static struct console hvc_console = { |
|
.name = "hvc", |
|
.write = hvc_console_print, |
|
.device = hvc_console_device, |
|
.setup = hvc_console_setup, |
|
.flags = CON_PRINTBUFFER, |
|
.index = -1, |
|
}; |
|
|
|
/* |
|
* Early console initialization. Precedes driver initialization. |
|
* |
|
* (1) we are first, and the user specified another driver |
|
* -- index will remain -1 |
|
* (2) we are first and the user specified no driver |
|
* -- index will be set to 0, then we will fail setup. |
|
* (3) we are first and the user specified our driver |
|
* -- index will be set to user specified driver, and we will fail |
|
* (4) we are after driver, and this initcall will register us |
|
* -- if the user didn't specify a driver then the console will match |
|
* |
|
* Note that for cases 2 and 3, we will match later when the io driver |
|
* calls hvc_instantiate() and call register again. |
|
*/ |
|
static int __init hvc_console_init(void) |
|
{ |
|
register_console(&hvc_console); |
|
return 0; |
|
} |
|
console_initcall(hvc_console_init); |
|
|
|
/* callback when the kboject ref count reaches zero. */ |
|
static void hvc_port_destruct(struct tty_port *port) |
|
{ |
|
struct hvc_struct *hp = container_of(port, struct hvc_struct, port); |
|
unsigned long flags; |
|
|
|
mutex_lock(&hvc_structs_mutex); |
|
|
|
spin_lock_irqsave(&hp->lock, flags); |
|
list_del(&(hp->next)); |
|
spin_unlock_irqrestore(&hp->lock, flags); |
|
|
|
mutex_unlock(&hvc_structs_mutex); |
|
|
|
kfree(hp); |
|
} |
|
|
|
static void hvc_check_console(int index) |
|
{ |
|
/* Already enabled, bail out */ |
|
if (hvc_console.flags & CON_ENABLED) |
|
return; |
|
|
|
/* If this index is what the user requested, then register |
|
* now (setup won't fail at this point). It's ok to just |
|
* call register again if previously .setup failed. |
|
*/ |
|
if (index == hvc_console.index) |
|
register_console(&hvc_console); |
|
} |
|
|
|
/* |
|
* hvc_instantiate() is an early console discovery method which locates |
|
* consoles * prior to the vio subsystem discovering them. Hotplugged |
|
* vty adapters do NOT get an hvc_instantiate() callback since they |
|
* appear after early console init. |
|
*/ |
|
int hvc_instantiate(uint32_t vtermno, int index, const struct hv_ops *ops) |
|
{ |
|
struct hvc_struct *hp; |
|
|
|
if (index < 0 || index >= MAX_NR_HVC_CONSOLES) |
|
return -1; |
|
|
|
if (vtermnos[index] != -1) |
|
return -1; |
|
|
|
/* make sure no tty has been registered in this index */ |
|
hp = hvc_get_by_index(index); |
|
if (hp) { |
|
tty_port_put(&hp->port); |
|
return -1; |
|
} |
|
|
|
vtermnos[index] = vtermno; |
|
cons_ops[index] = ops; |
|
|
|
/* check if we need to re-register the kernel console */ |
|
hvc_check_console(index); |
|
|
|
return 0; |
|
} |
|
EXPORT_SYMBOL_GPL(hvc_instantiate); |
|
|
|
/* Wake the sleeping khvcd */ |
|
void hvc_kick(void) |
|
{ |
|
hvc_kicked = 1; |
|
wake_up_process(hvc_task); |
|
} |
|
EXPORT_SYMBOL_GPL(hvc_kick); |
|
|
|
static void hvc_unthrottle(struct tty_struct *tty) |
|
{ |
|
hvc_kick(); |
|
} |
|
|
|
static int hvc_install(struct tty_driver *driver, struct tty_struct *tty) |
|
{ |
|
struct hvc_struct *hp; |
|
int rc; |
|
|
|
/* Auto increments kref reference if found. */ |
|
hp = hvc_get_by_index(tty->index); |
|
if (!hp) |
|
return -ENODEV; |
|
|
|
tty->driver_data = hp; |
|
|
|
rc = tty_port_install(&hp->port, driver, tty); |
|
if (rc) |
|
tty_port_put(&hp->port); |
|
return rc; |
|
} |
|
|
|
/* |
|
* The TTY interface won't be used until after the vio layer has exposed the vty |
|
* adapter to the kernel. |
|
*/ |
|
static int hvc_open(struct tty_struct *tty, struct file * filp) |
|
{ |
|
struct hvc_struct *hp = tty->driver_data; |
|
unsigned long flags; |
|
int rc = 0; |
|
|
|
spin_lock_irqsave(&hp->port.lock, flags); |
|
/* Check and then increment for fast path open. */ |
|
if (hp->port.count++ > 0) { |
|
spin_unlock_irqrestore(&hp->port.lock, flags); |
|
hvc_kick(); |
|
return 0; |
|
} /* else count == 0 */ |
|
spin_unlock_irqrestore(&hp->port.lock, flags); |
|
|
|
tty_port_tty_set(&hp->port, tty); |
|
|
|
if (hp->ops->notifier_add) |
|
rc = hp->ops->notifier_add(hp, hp->data); |
|
|
|
/* |
|
* If the notifier fails we return an error. The tty layer |
|
* will call hvc_close() after a failed open but we don't want to clean |
|
* up there so we'll clean up here and clear out the previously set |
|
* tty fields and return the kref reference. |
|
*/ |
|
if (rc) { |
|
printk(KERN_ERR "hvc_open: request_irq failed with rc %d.\n", rc); |
|
} else { |
|
/* We are ready... raise DTR/RTS */ |
|
if (C_BAUD(tty)) |
|
if (hp->ops->dtr_rts) |
|
hp->ops->dtr_rts(hp, 1); |
|
tty_port_set_initialized(&hp->port, true); |
|
} |
|
|
|
/* Force wakeup of the polling thread */ |
|
hvc_kick(); |
|
|
|
return rc; |
|
} |
|
|
|
static void hvc_close(struct tty_struct *tty, struct file * filp) |
|
{ |
|
struct hvc_struct *hp = tty->driver_data; |
|
unsigned long flags; |
|
|
|
if (tty_hung_up_p(filp)) |
|
return; |
|
|
|
spin_lock_irqsave(&hp->port.lock, flags); |
|
|
|
if (--hp->port.count == 0) { |
|
spin_unlock_irqrestore(&hp->port.lock, flags); |
|
/* 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); |
|
|
|
if (hp->ops->notifier_del) |
|
hp->ops->notifier_del(hp, hp->data); |
|
|
|
/* cancel pending tty resize work */ |
|
cancel_work_sync(&hp->tty_resize); |
|
|
|
/* |
|
* Chain calls chars_in_buffer() and returns immediately if |
|
* there is no buffered data otherwise sleeps on a wait queue |
|
* 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", |
|
hp->vtermno, hp->port.count); |
|
spin_unlock_irqrestore(&hp->port.lock, flags); |
|
} |
|
} |
|
|
|
static void hvc_cleanup(struct tty_struct *tty) |
|
{ |
|
struct hvc_struct *hp = tty->driver_data; |
|
|
|
tty_port_put(&hp->port); |
|
} |
|
|
|
static void hvc_hangup(struct tty_struct *tty) |
|
{ |
|
struct hvc_struct *hp = tty->driver_data; |
|
unsigned long flags; |
|
|
|
if (!hp) |
|
return; |
|
|
|
/* cancel pending tty resize work */ |
|
cancel_work_sync(&hp->tty_resize); |
|
|
|
spin_lock_irqsave(&hp->port.lock, flags); |
|
|
|
/* |
|
* The N_TTY line discipline has problems such that in a close vs |
|
* open->hangup case this can be called after the final close so prevent |
|
* that from happening for now. |
|
*/ |
|
if (hp->port.count <= 0) { |
|
spin_unlock_irqrestore(&hp->port.lock, flags); |
|
return; |
|
} |
|
|
|
hp->port.count = 0; |
|
spin_unlock_irqrestore(&hp->port.lock, flags); |
|
tty_port_tty_set(&hp->port, NULL); |
|
|
|
hp->n_outbuf = 0; |
|
|
|
if (hp->ops->notifier_hangup) |
|
hp->ops->notifier_hangup(hp, hp->data); |
|
} |
|
|
|
/* |
|
* Push buffered characters whether they were just recently buffered or waiting |
|
* on a blocked hypervisor. Call this function with hp->lock held. |
|
*/ |
|
static int hvc_push(struct hvc_struct *hp) |
|
{ |
|
int n; |
|
|
|
n = hp->ops->put_chars(hp->vtermno, hp->outbuf, hp->n_outbuf); |
|
if (n <= 0) { |
|
if (n == 0 || n == -EAGAIN) { |
|
hp->do_wakeup = 1; |
|
return 0; |
|
} |
|
/* throw away output on error; this happens when |
|
there is no session connected to the vterm. */ |
|
hp->n_outbuf = 0; |
|
} else |
|
hp->n_outbuf -= n; |
|
if (hp->n_outbuf > 0) |
|
memmove(hp->outbuf, hp->outbuf + n, hp->n_outbuf); |
|
else |
|
hp->do_wakeup = 1; |
|
|
|
return n; |
|
} |
|
|
|
static int hvc_write(struct tty_struct *tty, const unsigned char *buf, int count) |
|
{ |
|
struct hvc_struct *hp = tty->driver_data; |
|
unsigned long flags; |
|
int rsize, written = 0; |
|
|
|
/* This write was probably executed during a tty close. */ |
|
if (!hp) |
|
return -EPIPE; |
|
|
|
/* FIXME what's this (unprotected) check for? */ |
|
if (hp->port.count <= 0) |
|
return -EIO; |
|
|
|
while (count > 0) { |
|
int ret = 0; |
|
|
|
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(); |
|
} |
|
} |
|
|
|
/* |
|
* Racy, but harmless, kick thread if there is still pending data. |
|
*/ |
|
if (hp->n_outbuf) |
|
hvc_kick(); |
|
|
|
return written; |
|
} |
|
|
|
/** |
|
* hvc_set_winsz() - Resize the hvc tty terminal window. |
|
* @work: work structure. |
|
* |
|
* The routine shall not be called within an atomic context because it |
|
* might sleep. |
|
* |
|
* Locking: hp->lock |
|
*/ |
|
static void hvc_set_winsz(struct work_struct *work) |
|
{ |
|
struct hvc_struct *hp; |
|
unsigned long hvc_flags; |
|
struct tty_struct *tty; |
|
struct winsize ws; |
|
|
|
hp = container_of(work, struct hvc_struct, tty_resize); |
|
|
|
tty = tty_port_tty_get(&hp->port); |
|
if (!tty) |
|
return; |
|
|
|
spin_lock_irqsave(&hp->lock, hvc_flags); |
|
ws = hp->ws; |
|
spin_unlock_irqrestore(&hp->lock, hvc_flags); |
|
|
|
tty_do_resize(tty, &ws); |
|
tty_kref_put(tty); |
|
} |
|
|
|
/* |
|
* This is actually a contract between the driver and the tty layer outlining |
|
* how much write room the driver can guarantee will be sent OR BUFFERED. This |
|
* driver MUST honor the return value. |
|
*/ |
|
static unsigned int hvc_write_room(struct tty_struct *tty) |
|
{ |
|
struct hvc_struct *hp = tty->driver_data; |
|
|
|
if (!hp) |
|
return 0; |
|
|
|
return hp->outbuf_size - hp->n_outbuf; |
|
} |
|
|
|
static unsigned int hvc_chars_in_buffer(struct tty_struct *tty) |
|
{ |
|
struct hvc_struct *hp = tty->driver_data; |
|
|
|
if (!hp) |
|
return 0; |
|
return hp->n_outbuf; |
|
} |
|
|
|
/* |
|
* timeout will vary between the MIN and MAX values defined here. By default |
|
* and during console activity we will use a default MIN_TIMEOUT of 10. When |
|
* the console is idle, we increase the timeout value on each pass through |
|
* msleep until we reach the max. This may be noticeable as a brief (average |
|
* one second) delay on the console before the console responds to input when |
|
* there has been no input for some time. |
|
*/ |
|
#define MIN_TIMEOUT (10) |
|
#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 |
|
|
|
static int __hvc_poll(struct hvc_struct *hp, bool may_sleep) |
|
{ |
|
struct tty_struct *tty; |
|
int i, n, count, poll_mask = 0; |
|
char buf[N_INBUF] __ALIGNED__; |
|
unsigned long flags; |
|
int read_total = 0; |
|
int written_total = 0; |
|
|
|
spin_lock_irqsave(&hp->lock, flags); |
|
|
|
/* Push pending writes */ |
|
if (hp->n_outbuf > 0) |
|
written_total = hvc_push(hp); |
|
|
|
/* Reschedule us if still some write pending */ |
|
if (hp->n_outbuf > 0) { |
|
poll_mask |= HVC_POLL_WRITE; |
|
/* If hvc_push() was not able to write, sleep a few msecs */ |
|
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) |
|
goto bail; |
|
|
|
/* Now check if we can get data (are we throttled ?) */ |
|
if (tty_throttled(tty)) |
|
goto out; |
|
|
|
/* If we aren't notifier driven and aren't throttled, we always |
|
* request a reschedule |
|
*/ |
|
if (!hp->irq_requested) |
|
poll_mask |= HVC_POLL_READ; |
|
|
|
read_again: |
|
/* Read data if any */ |
|
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; |
|
} |
|
|
|
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; |
|
} |
|
goto out; |
|
} |
|
|
|
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; |
|
continue; |
|
} |
|
} |
|
#endif /* CONFIG_MAGIC_SYSRQ */ |
|
tty_insert_flip_char(&hp->port, buf[i], 0); |
|
} |
|
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; |
|
} |
|
|
|
/* |
|
* 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; |
|
tty_wakeup(tty); |
|
} |
|
bail: |
|
spin_unlock_irqrestore(&hp->lock, flags); |
|
|
|
if (read_total) { |
|
/* Activity is occurring, so reset the polling backoff value to |
|
a minimum for performance. */ |
|
timeout = MIN_TIMEOUT; |
|
|
|
tty_flip_buffer_push(&hp->port); |
|
} |
|
tty_kref_put(tty); |
|
|
|
return poll_mask; |
|
} |
|
|
|
int hvc_poll(struct hvc_struct *hp) |
|
{ |
|
return __hvc_poll(hp, false); |
|
} |
|
EXPORT_SYMBOL_GPL(hvc_poll); |
|
|
|
/** |
|
* __hvc_resize() - Update terminal window size information. |
|
* @hp: HVC console pointer |
|
* @ws: Terminal window size structure |
|
* |
|
* Stores the specified window size information in the hvc structure of @hp. |
|
* The function schedule the tty resize update. |
|
* |
|
* Locking: Locking free; the function MUST be called holding hp->lock |
|
*/ |
|
void __hvc_resize(struct hvc_struct *hp, struct winsize ws) |
|
{ |
|
hp->ws = ws; |
|
schedule_work(&hp->tty_resize); |
|
} |
|
EXPORT_SYMBOL_GPL(__hvc_resize); |
|
|
|
/* |
|
* This kthread is either polling or interrupt driven. This is determined by |
|
* calling hvc_poll() who determines whether a console adapter support |
|
* interrupts. |
|
*/ |
|
static int khvcd(void *unused) |
|
{ |
|
int poll_mask; |
|
struct hvc_struct *hp; |
|
|
|
set_freezable(); |
|
do { |
|
poll_mask = 0; |
|
hvc_kicked = 0; |
|
try_to_freeze(); |
|
wmb(); |
|
if (!cpus_are_in_xmon()) { |
|
mutex_lock(&hvc_structs_mutex); |
|
list_for_each_entry(hp, &hvc_structs, next) { |
|
poll_mask |= __hvc_poll(hp, true); |
|
cond_resched(); |
|
} |
|
mutex_unlock(&hvc_structs_mutex); |
|
} else |
|
poll_mask |= HVC_POLL_READ; |
|
if (hvc_kicked) |
|
continue; |
|
set_current_state(TASK_INTERRUPTIBLE); |
|
if (!hvc_kicked) { |
|
if (poll_mask == 0) |
|
schedule(); |
|
else { |
|
unsigned long j_timeout; |
|
|
|
if (timeout < MAX_TIMEOUT) |
|
timeout += (timeout >> 6) + 1; |
|
|
|
/* |
|
* We don't use msleep_interruptible otherwise |
|
* "kick" will fail to wake us up |
|
*/ |
|
j_timeout = msecs_to_jiffies(timeout) + 1; |
|
schedule_timeout_interruptible(j_timeout); |
|
} |
|
} |
|
__set_current_state(TASK_RUNNING); |
|
} while (!kthread_should_stop()); |
|
|
|
return 0; |
|
} |
|
|
|
static int hvc_tiocmget(struct tty_struct *tty) |
|
{ |
|
struct hvc_struct *hp = tty->driver_data; |
|
|
|
if (!hp || !hp->ops->tiocmget) |
|
return -EINVAL; |
|
return hp->ops->tiocmget(hp); |
|
} |
|
|
|
static int hvc_tiocmset(struct tty_struct *tty, |
|
unsigned int set, unsigned int clear) |
|
{ |
|
struct hvc_struct *hp = tty->driver_data; |
|
|
|
if (!hp || !hp->ops->tiocmset) |
|
return -EINVAL; |
|
return hp->ops->tiocmset(hp, set, clear); |
|
} |
|
|
|
#ifdef CONFIG_CONSOLE_POLL |
|
static int hvc_poll_init(struct tty_driver *driver, int line, char *options) |
|
{ |
|
return 0; |
|
} |
|
|
|
static int hvc_poll_get_char(struct tty_driver *driver, int line) |
|
{ |
|
struct tty_struct *tty = driver->ttys[0]; |
|
struct hvc_struct *hp = tty->driver_data; |
|
int n; |
|
char ch; |
|
|
|
n = hp->ops->get_chars(hp->vtermno, &ch, 1); |
|
|
|
if (n <= 0) |
|
return NO_POLL_CHAR; |
|
|
|
return ch; |
|
} |
|
|
|
static void hvc_poll_put_char(struct tty_driver *driver, int line, char ch) |
|
{ |
|
struct tty_struct *tty = driver->ttys[0]; |
|
struct hvc_struct *hp = tty->driver_data; |
|
int n; |
|
|
|
do { |
|
n = hp->ops->put_chars(hp->vtermno, &ch, 1); |
|
} while (n <= 0); |
|
} |
|
#endif |
|
|
|
static const struct tty_operations hvc_ops = { |
|
.install = hvc_install, |
|
.open = hvc_open, |
|
.close = hvc_close, |
|
.cleanup = hvc_cleanup, |
|
.write = hvc_write, |
|
.hangup = hvc_hangup, |
|
.unthrottle = hvc_unthrottle, |
|
.write_room = hvc_write_room, |
|
.chars_in_buffer = hvc_chars_in_buffer, |
|
.tiocmget = hvc_tiocmget, |
|
.tiocmset = hvc_tiocmset, |
|
#ifdef CONFIG_CONSOLE_POLL |
|
.poll_init = hvc_poll_init, |
|
.poll_get_char = hvc_poll_get_char, |
|
.poll_put_char = hvc_poll_put_char, |
|
#endif |
|
}; |
|
|
|
static const struct tty_port_operations hvc_port_ops = { |
|
.destruct = hvc_port_destruct, |
|
}; |
|
|
|
struct hvc_struct *hvc_alloc(uint32_t vtermno, int data, |
|
const struct hv_ops *ops, |
|
int outbuf_size) |
|
{ |
|
struct hvc_struct *hp; |
|
int i; |
|
|
|
/* We wait until a driver actually comes along */ |
|
if (atomic_inc_not_zero(&hvc_needs_init)) { |
|
int err = hvc_init(); |
|
if (err) |
|
return ERR_PTR(err); |
|
} |
|
|
|
hp = kzalloc(ALIGN(sizeof(*hp), sizeof(long)) + outbuf_size, |
|
GFP_KERNEL); |
|
if (!hp) |
|
return ERR_PTR(-ENOMEM); |
|
|
|
hp->vtermno = vtermno; |
|
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); |
|
mutex_lock(&hvc_structs_mutex); |
|
|
|
/* |
|
* find index to use: |
|
* see if this vterm id matches one registered for console. |
|
*/ |
|
for (i=0; i < MAX_NR_HVC_CONSOLES; i++) |
|
if (vtermnos[i] == hp->vtermno && |
|
cons_ops[i] == hp->ops) |
|
break; |
|
|
|
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; |
|
if (i < MAX_NR_HVC_CONSOLES) { |
|
cons_ops[i] = ops; |
|
vtermnos[i] = vtermno; |
|
} |
|
|
|
list_add_tail(&(hp->next), &hvc_structs); |
|
mutex_unlock(&hvc_structs_mutex); |
|
|
|
/* check if we need to re-register the kernel console */ |
|
hvc_check_console(i); |
|
|
|
return hp; |
|
} |
|
EXPORT_SYMBOL_GPL(hvc_alloc); |
|
|
|
int hvc_remove(struct hvc_struct *hp) |
|
{ |
|
unsigned long flags; |
|
struct tty_struct *tty; |
|
|
|
tty = tty_port_tty_get(&hp->port); |
|
|
|
console_lock(); |
|
spin_lock_irqsave(&hp->lock, flags); |
|
if (hp->index < MAX_NR_HVC_CONSOLES) { |
|
vtermnos[hp->index] = -1; |
|
cons_ops[hp->index] = NULL; |
|
} |
|
|
|
/* Don't whack hp->irq because tty_hangup() will need to free the irq. */ |
|
|
|
spin_unlock_irqrestore(&hp->lock, flags); |
|
console_unlock(); |
|
|
|
/* |
|
* We 'put' the instance that was grabbed when the kref instance |
|
* was initialized using kref_init(). Let the last holder of this |
|
* kref cause it to be removed, which will probably be the tty_vhangup |
|
* below. |
|
*/ |
|
tty_port_put(&hp->port); |
|
|
|
/* |
|
* This function call will auto chain call hvc_hangup. |
|
*/ |
|
if (tty) { |
|
tty_vhangup(tty); |
|
tty_kref_put(tty); |
|
} |
|
return 0; |
|
} |
|
EXPORT_SYMBOL_GPL(hvc_remove); |
|
|
|
/* Driver initialization: called as soon as someone uses hvc_alloc(). */ |
|
static int hvc_init(void) |
|
{ |
|
struct tty_driver *drv; |
|
int err; |
|
|
|
/* We need more than hvc_count adapters due to hotplug additions. */ |
|
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; |
|
} |
|
|
|
drv->driver_name = "hvc"; |
|
drv->name = "hvc"; |
|
drv->major = HVC_MAJOR; |
|
drv->minor_start = HVC_MINOR; |
|
drv->type = TTY_DRIVER_TYPE_SYSTEM; |
|
drv->init_termios = tty_std_termios; |
|
tty_set_operations(drv, &hvc_ops); |
|
|
|
/* Always start the kthread because there can be hotplug vty adapters |
|
* added later. */ |
|
hvc_task = kthread_run(khvcd, NULL, "khvcd"); |
|
if (IS_ERR(hvc_task)) { |
|
printk(KERN_ERR "Couldn't create kthread for console.\n"); |
|
err = PTR_ERR(hvc_task); |
|
goto put_tty; |
|
} |
|
|
|
err = tty_register_driver(drv); |
|
if (err) { |
|
printk(KERN_ERR "Couldn't register hvc console driver\n"); |
|
goto stop_thread; |
|
} |
|
|
|
/* |
|
* Make sure tty is fully registered before allowing it to be |
|
* found by hvc_console_device. |
|
*/ |
|
smp_mb(); |
|
hvc_driver = drv; |
|
return 0; |
|
|
|
stop_thread: |
|
kthread_stop(hvc_task); |
|
hvc_task = NULL; |
|
put_tty: |
|
tty_driver_kref_put(drv); |
|
out: |
|
return err; |
|
}
|
|
|