linux/drivers/s390/char/con3270.c
Martin Schwidefsky 5712f3301a s390/3270: fix lockdep false positive on view->lock
The spinlock in the raw3270_view structure is used by con3270, tty3270
and fs3270 in different ways. For con3270 the lock can be acquired in
irq context, for tty3270 and fs3270 the highest context is bh.

Lockdep sees the view->lock as a single class and if the 3270 driver
is used for the console the following message is generated:

WARNING: inconsistent lock state
5.1.0-rc3-05157-g5c168033979d #12 Not tainted
--------------------------------
inconsistent {IN-HARDIRQ-W} -> {HARDIRQ-ON-W} usage.
swapper/0/1 [HC0[0]:SC1[1]:HE1:SE0] takes:
(____ptrval____) (&(&view->lock)->rlock){?.-.}, at: tty3270_update+0x7c/0x330

Introduce a lockdep subclass for the view lock to distinguish bh from
irq locks.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2019-04-10 17:46:22 +02:00

650 lines
16 KiB
C

// SPDX-License-Identifier: GPL-2.0
/*
* IBM/3270 Driver - console view.
*
* Author(s):
* Original 3270 Code for 2.4 written by Richard Hitt (UTS Global)
* Rewritten for 2.5 by Martin Schwidefsky <schwidefsky@de.ibm.com>
* Copyright IBM Corp. 2003, 2009
*/
#include <linux/module.h>
#include <linux/console.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/list.h>
#include <linux/types.h>
#include <linux/slab.h>
#include <linux/err.h>
#include <linux/reboot.h>
#include <asm/ccwdev.h>
#include <asm/cio.h>
#include <asm/cpcmd.h>
#include <asm/ebcdic.h>
#include "raw3270.h"
#include "tty3270.h"
#include "ctrlchar.h"
#define CON3270_OUTPUT_BUFFER_SIZE 1024
#define CON3270_STRING_PAGES 4
static struct raw3270_fn con3270_fn;
static bool auto_update = true;
module_param(auto_update, bool, 0);
/*
* Main 3270 console view data structure.
*/
struct con3270 {
struct raw3270_view view;
struct list_head freemem; /* list of free memory for strings. */
/* Output stuff. */
struct list_head lines; /* list of lines. */
struct list_head update; /* list of lines to update. */
int line_nr; /* line number for next update. */
int nr_lines; /* # lines in list. */
int nr_up; /* # lines up in history. */
unsigned long update_flags; /* Update indication bits. */
struct string *cline; /* current output line. */
struct string *status; /* last line of display. */
struct raw3270_request *write; /* single write request. */
struct timer_list timer;
/* Input stuff. */
struct string *input; /* input string for read request. */
struct raw3270_request *read; /* single read request. */
struct raw3270_request *kreset; /* single keyboard reset request. */
struct tasklet_struct readlet; /* tasklet to issue read request. */
};
static struct con3270 *condev;
/* con3270->update_flags. See con3270_update for details. */
#define CON_UPDATE_ERASE 1 /* Use EWRITEA instead of WRITE. */
#define CON_UPDATE_LIST 2 /* Update lines in tty3270->update. */
#define CON_UPDATE_STATUS 4 /* Update status line. */
#define CON_UPDATE_ALL 8 /* Recreate screen. */
static void con3270_update(struct timer_list *);
/*
* Setup timeout for a device. On timeout trigger an update.
*/
static void con3270_set_timer(struct con3270 *cp, int expires)
{
if (expires == 0)
del_timer(&cp->timer);
else
mod_timer(&cp->timer, jiffies + expires);
}
/*
* The status line is the last line of the screen. It shows the string
* "console view" in the lower left corner and "Running"/"More..."/"Holding"
* in the lower right corner of the screen.
*/
static void
con3270_update_status(struct con3270 *cp)
{
char *str;
str = (cp->nr_up != 0) ? "History" : "Running";
memcpy(cp->status->string + 24, str, 7);
codepage_convert(cp->view.ascebc, cp->status->string + 24, 7);
cp->update_flags |= CON_UPDATE_STATUS;
}
static void
con3270_create_status(struct con3270 *cp)
{
static const unsigned char blueprint[] =
{ TO_SBA, 0, 0, TO_SF,TF_LOG,TO_SA,TAT_COLOR, TAC_GREEN,
'c','o','n','s','o','l','e',' ','v','i','e','w',
TO_RA,0,0,0,'R','u','n','n','i','n','g',TO_SF,TF_LOG };
cp->status = alloc_string(&cp->freemem, sizeof(blueprint));
/* Copy blueprint to status line */
memcpy(cp->status->string, blueprint, sizeof(blueprint));
/* Set TO_RA addresses. */
raw3270_buffer_address(cp->view.dev, cp->status->string + 1,
cp->view.cols * (cp->view.rows - 1));
raw3270_buffer_address(cp->view.dev, cp->status->string + 21,
cp->view.cols * cp->view.rows - 8);
/* Convert strings to ebcdic. */
codepage_convert(cp->view.ascebc, cp->status->string + 8, 12);
codepage_convert(cp->view.ascebc, cp->status->string + 24, 7);
}
/*
* Set output offsets to 3270 datastream fragment of a console string.
*/
static void
con3270_update_string(struct con3270 *cp, struct string *s, int nr)
{
if (s->len < 4) {
/* This indicates a bug, but printing a warning would
* cause a deadlock. */
return;
}
if (s->string[s->len - 4] != TO_RA)
return;
raw3270_buffer_address(cp->view.dev, s->string + s->len - 3,
cp->view.cols * (nr + 1));
}
/*
* Rebuild update list to print all lines.
*/
static void
con3270_rebuild_update(struct con3270 *cp)
{
struct string *s, *n;
int nr;
/*
* Throw away update list and create a new one,
* containing all lines that will fit on the screen.
*/
list_for_each_entry_safe(s, n, &cp->update, update)
list_del_init(&s->update);
nr = cp->view.rows - 2 + cp->nr_up;
list_for_each_entry_reverse(s, &cp->lines, list) {
if (nr < cp->view.rows - 1)
list_add(&s->update, &cp->update);
if (--nr < 0)
break;
}
cp->line_nr = 0;
cp->update_flags |= CON_UPDATE_LIST;
}
/*
* Alloc string for size bytes. Free strings from history if necessary.
*/
static struct string *
con3270_alloc_string(struct con3270 *cp, size_t size)
{
struct string *s, *n;
s = alloc_string(&cp->freemem, size);
if (s)
return s;
list_for_each_entry_safe(s, n, &cp->lines, list) {
list_del(&s->list);
if (!list_empty(&s->update))
list_del(&s->update);
cp->nr_lines--;
if (free_string(&cp->freemem, s) >= size)
break;
}
s = alloc_string(&cp->freemem, size);
BUG_ON(!s);
if (cp->nr_up != 0 && cp->nr_up + cp->view.rows > cp->nr_lines) {
cp->nr_up = cp->nr_lines - cp->view.rows + 1;
con3270_rebuild_update(cp);
con3270_update_status(cp);
}
return s;
}
/*
* Write completion callback.
*/
static void
con3270_write_callback(struct raw3270_request *rq, void *data)
{
raw3270_request_reset(rq);
xchg(&((struct con3270 *) rq->view)->write, rq);
}
/*
* Update console display.
*/
static void
con3270_update(struct timer_list *t)
{
struct con3270 *cp = from_timer(cp, t, timer);
struct raw3270_request *wrq;
char wcc, prolog[6];
unsigned long flags;
unsigned long updated;
struct string *s, *n;
int rc;
if (!auto_update && !raw3270_view_active(&cp->view))
return;
if (cp->view.dev)
raw3270_activate_view(&cp->view);
wrq = xchg(&cp->write, 0);
if (!wrq) {
con3270_set_timer(cp, 1);
return;
}
spin_lock_irqsave(&cp->view.lock, flags);
updated = 0;
if (cp->update_flags & CON_UPDATE_ALL) {
con3270_rebuild_update(cp);
con3270_update_status(cp);
cp->update_flags = CON_UPDATE_ERASE | CON_UPDATE_LIST |
CON_UPDATE_STATUS;
}
if (cp->update_flags & CON_UPDATE_ERASE) {
/* Use erase write alternate to initialize display. */
raw3270_request_set_cmd(wrq, TC_EWRITEA);
updated |= CON_UPDATE_ERASE;
} else
raw3270_request_set_cmd(wrq, TC_WRITE);
wcc = TW_NONE;
raw3270_request_add_data(wrq, &wcc, 1);
/*
* Update status line.
*/
if (cp->update_flags & CON_UPDATE_STATUS)
if (raw3270_request_add_data(wrq, cp->status->string,
cp->status->len) == 0)
updated |= CON_UPDATE_STATUS;
if (cp->update_flags & CON_UPDATE_LIST) {
prolog[0] = TO_SBA;
prolog[3] = TO_SA;
prolog[4] = TAT_COLOR;
prolog[5] = TAC_TURQ;
raw3270_buffer_address(cp->view.dev, prolog + 1,
cp->view.cols * cp->line_nr);
raw3270_request_add_data(wrq, prolog, 6);
/* Write strings in the update list to the screen. */
list_for_each_entry_safe(s, n, &cp->update, update) {
if (s != cp->cline)
con3270_update_string(cp, s, cp->line_nr);
if (raw3270_request_add_data(wrq, s->string,
s->len) != 0)
break;
list_del_init(&s->update);
if (s != cp->cline)
cp->line_nr++;
}
if (list_empty(&cp->update))
updated |= CON_UPDATE_LIST;
}
wrq->callback = con3270_write_callback;
rc = raw3270_start(&cp->view, wrq);
if (rc == 0) {
cp->update_flags &= ~updated;
if (cp->update_flags)
con3270_set_timer(cp, 1);
} else {
raw3270_request_reset(wrq);
xchg(&cp->write, wrq);
}
spin_unlock_irqrestore(&cp->view.lock, flags);
}
/*
* Read tasklet.
*/
static void
con3270_read_tasklet(struct raw3270_request *rrq)
{
static char kreset_data = TW_KR;
struct con3270 *cp;
unsigned long flags;
int nr_up, deactivate;
cp = (struct con3270 *) rrq->view;
spin_lock_irqsave(&cp->view.lock, flags);
nr_up = cp->nr_up;
deactivate = 0;
/* Check aid byte. */
switch (cp->input->string[0]) {
case 0x7d: /* enter: jump to bottom. */
nr_up = 0;
break;
case 0xf3: /* PF3: deactivate the console view. */
deactivate = 1;
break;
case 0x6d: /* clear: start from scratch. */
cp->update_flags = CON_UPDATE_ALL;
con3270_set_timer(cp, 1);
break;
case 0xf7: /* PF7: do a page up in the console log. */
nr_up += cp->view.rows - 2;
if (nr_up + cp->view.rows - 1 > cp->nr_lines) {
nr_up = cp->nr_lines - cp->view.rows + 1;
if (nr_up < 0)
nr_up = 0;
}
break;
case 0xf8: /* PF8: do a page down in the console log. */
nr_up -= cp->view.rows - 2;
if (nr_up < 0)
nr_up = 0;
break;
}
if (nr_up != cp->nr_up) {
cp->nr_up = nr_up;
con3270_rebuild_update(cp);
con3270_update_status(cp);
con3270_set_timer(cp, 1);
}
spin_unlock_irqrestore(&cp->view.lock, flags);
/* Start keyboard reset command. */
raw3270_request_reset(cp->kreset);
raw3270_request_set_cmd(cp->kreset, TC_WRITE);
raw3270_request_add_data(cp->kreset, &kreset_data, 1);
raw3270_start(&cp->view, cp->kreset);
if (deactivate)
raw3270_deactivate_view(&cp->view);
raw3270_request_reset(rrq);
xchg(&cp->read, rrq);
raw3270_put_view(&cp->view);
}
/*
* Read request completion callback.
*/
static void
con3270_read_callback(struct raw3270_request *rq, void *data)
{
raw3270_get_view(rq->view);
/* Schedule tasklet to pass input to tty. */
tasklet_schedule(&((struct con3270 *) rq->view)->readlet);
}
/*
* Issue a read request. Called only from interrupt function.
*/
static void
con3270_issue_read(struct con3270 *cp)
{
struct raw3270_request *rrq;
int rc;
rrq = xchg(&cp->read, 0);
if (!rrq)
/* Read already scheduled. */
return;
rrq->callback = con3270_read_callback;
rrq->callback_data = cp;
raw3270_request_set_cmd(rrq, TC_READMOD);
raw3270_request_set_data(rrq, cp->input->string, cp->input->len);
/* Issue the read modified request. */
rc = raw3270_start_irq(&cp->view, rrq);
if (rc)
raw3270_request_reset(rrq);
}
/*
* Switch to the console view.
*/
static int
con3270_activate(struct raw3270_view *view)
{
struct con3270 *cp;
cp = (struct con3270 *) view;
cp->update_flags = CON_UPDATE_ALL;
con3270_set_timer(cp, 1);
return 0;
}
static void
con3270_deactivate(struct raw3270_view *view)
{
struct con3270 *cp;
cp = (struct con3270 *) view;
del_timer(&cp->timer);
}
static void
con3270_irq(struct con3270 *cp, struct raw3270_request *rq, struct irb *irb)
{
/* Handle ATTN. Schedule tasklet to read aid. */
if (irb->scsw.cmd.dstat & DEV_STAT_ATTENTION)
con3270_issue_read(cp);
if (rq) {
if (irb->scsw.cmd.dstat & DEV_STAT_UNIT_CHECK)
rq->rc = -EIO;
else
/* Normal end. Copy residual count. */
rq->rescnt = irb->scsw.cmd.count;
} else if (irb->scsw.cmd.dstat & DEV_STAT_DEV_END) {
/* Interrupt without an outstanding request -> update all */
cp->update_flags = CON_UPDATE_ALL;
con3270_set_timer(cp, 1);
}
}
/* Console view to a 3270 device. */
static struct raw3270_fn con3270_fn = {
.activate = con3270_activate,
.deactivate = con3270_deactivate,
.intv = (void *) con3270_irq
};
static inline void
con3270_cline_add(struct con3270 *cp)
{
if (!list_empty(&cp->cline->list))
/* Already added. */
return;
list_add_tail(&cp->cline->list, &cp->lines);
cp->nr_lines++;
con3270_rebuild_update(cp);
}
static inline void
con3270_cline_insert(struct con3270 *cp, unsigned char c)
{
cp->cline->string[cp->cline->len++] =
cp->view.ascebc[(c < ' ') ? ' ' : c];
if (list_empty(&cp->cline->update)) {
list_add_tail(&cp->cline->update, &cp->update);
cp->update_flags |= CON_UPDATE_LIST;
}
}
static inline void
con3270_cline_end(struct con3270 *cp)
{
struct string *s;
unsigned int size;
/* Copy cline. */
size = (cp->cline->len < cp->view.cols - 5) ?
cp->cline->len + 4 : cp->view.cols;
s = con3270_alloc_string(cp, size);
memcpy(s->string, cp->cline->string, cp->cline->len);
if (cp->cline->len < cp->view.cols - 5) {
s->string[s->len - 4] = TO_RA;
s->string[s->len - 1] = 0;
} else {
while (--size >= cp->cline->len)
s->string[size] = cp->view.ascebc[' '];
}
/* Replace cline with allocated line s and reset cline. */
list_add(&s->list, &cp->cline->list);
list_del_init(&cp->cline->list);
if (!list_empty(&cp->cline->update)) {
list_add(&s->update, &cp->cline->update);
list_del_init(&cp->cline->update);
}
cp->cline->len = 0;
}
/*
* Write a string to the 3270 console
*/
static void
con3270_write(struct console *co, const char *str, unsigned int count)
{
struct con3270 *cp;
unsigned long flags;
unsigned char c;
cp = condev;
spin_lock_irqsave(&cp->view.lock, flags);
while (count-- > 0) {
c = *str++;
if (cp->cline->len == 0)
con3270_cline_add(cp);
if (c != '\n')
con3270_cline_insert(cp, c);
if (c == '\n' || cp->cline->len >= cp->view.cols)
con3270_cline_end(cp);
}
/* Setup timer to output current console buffer after 1/10 second */
cp->nr_up = 0;
if (cp->view.dev && !timer_pending(&cp->timer))
con3270_set_timer(cp, HZ/10);
spin_unlock_irqrestore(&cp->view.lock,flags);
}
static struct tty_driver *
con3270_device(struct console *c, int *index)
{
*index = c->index;
return tty3270_driver;
}
/*
* Wait for end of write request.
*/
static void
con3270_wait_write(struct con3270 *cp)
{
while (!cp->write) {
raw3270_wait_cons_dev(cp->view.dev);
barrier();
}
}
/*
* panic() calls con3270_flush through a panic_notifier
* before the system enters a disabled, endless loop.
*/
static void
con3270_flush(void)
{
struct con3270 *cp;
unsigned long flags;
cp = condev;
if (!cp->view.dev)
return;
raw3270_pm_unfreeze(&cp->view);
raw3270_activate_view(&cp->view);
spin_lock_irqsave(&cp->view.lock, flags);
con3270_wait_write(cp);
cp->nr_up = 0;
con3270_rebuild_update(cp);
con3270_update_status(cp);
while (cp->update_flags != 0) {
spin_unlock_irqrestore(&cp->view.lock, flags);
con3270_update(&cp->timer);
spin_lock_irqsave(&cp->view.lock, flags);
con3270_wait_write(cp);
}
spin_unlock_irqrestore(&cp->view.lock, flags);
}
static int con3270_notify(struct notifier_block *self,
unsigned long event, void *data)
{
con3270_flush();
return NOTIFY_OK;
}
static struct notifier_block on_panic_nb = {
.notifier_call = con3270_notify,
.priority = 0,
};
static struct notifier_block on_reboot_nb = {
.notifier_call = con3270_notify,
.priority = 0,
};
/*
* The console structure for the 3270 console
*/
static struct console con3270 = {
.name = "tty3270",
.write = con3270_write,
.device = con3270_device,
.flags = CON_PRINTBUFFER,
};
/*
* 3270 console initialization code called from console_init().
*/
static int __init
con3270_init(void)
{
struct raw3270 *rp;
void *cbuf;
int i;
/* Check if 3270 is to be the console */
if (!CONSOLE_IS_3270)
return -ENODEV;
/* Set the console mode for VM */
if (MACHINE_IS_VM) {
cpcmd("TERM CONMODE 3270", NULL, 0, NULL);
cpcmd("TERM AUTOCR OFF", NULL, 0, NULL);
}
rp = raw3270_setup_console();
if (IS_ERR(rp))
return PTR_ERR(rp);
condev = kzalloc(sizeof(struct con3270), GFP_KERNEL | GFP_DMA);
if (!condev)
return -ENOMEM;
condev->view.dev = rp;
condev->read = raw3270_request_alloc(0);
condev->read->callback = con3270_read_callback;
condev->read->callback_data = condev;
condev->write = raw3270_request_alloc(CON3270_OUTPUT_BUFFER_SIZE);
condev->kreset = raw3270_request_alloc(1);
INIT_LIST_HEAD(&condev->lines);
INIT_LIST_HEAD(&condev->update);
timer_setup(&condev->timer, con3270_update, 0);
tasklet_init(&condev->readlet,
(void (*)(unsigned long)) con3270_read_tasklet,
(unsigned long) condev->read);
raw3270_add_view(&condev->view, &con3270_fn, 1, RAW3270_VIEW_LOCK_IRQ);
INIT_LIST_HEAD(&condev->freemem);
for (i = 0; i < CON3270_STRING_PAGES; i++) {
cbuf = (void *) get_zeroed_page(GFP_KERNEL | GFP_DMA);
add_string_memory(&condev->freemem, cbuf, PAGE_SIZE);
}
condev->cline = alloc_string(&condev->freemem, condev->view.cols);
condev->cline->len = 0;
con3270_create_status(condev);
condev->input = alloc_string(&condev->freemem, 80);
atomic_notifier_chain_register(&panic_notifier_list, &on_panic_nb);
register_reboot_notifier(&on_reboot_nb);
register_console(&con3270);
return 0;
}
console_initcall(con3270_init);