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4ae46db99c
Currently many console drivers for s390 rely on panic/reboot notifiers to invoke callbacks on these events. The panic() function disables local IRQs, secondary CPUs and preemption, so callbacks invoked on panic are effectively running in atomic context. Happens that most of these console callbacks from s390 doesn't take the proper care with regards to atomic context, like taking spinlocks that might be taken in other function/CPU and hence will cause a lockup situation. The goal for this patch is to improve the notifiers reliability, acting on 4 console drivers, as detailed below: (1) con3215: changed a regular spinlock to the trylock alternative. (2) con3270: also changed a regular spinlock to its trylock counterpart, but here we also have another problem: raw3270_activate_view() takes a different spinlock. So, we worked a helper to validate if this other lock is safe to acquire, and if so, raw3270_activate_view() should be safe. Notice though that there is a functional change here: it's now possible to continue the notifier code [reaching con3270_wait_write() and con3270_rebuild_update()] without executing raw3270_activate_view(). (3) sclp: a global lock is used heavily in the functions called from the notifier, so we added a check here - if the lock is taken already, we just bail-out, preventing the lockup. (4) sclp_vt220: same as (3), a lock validation was added to prevent the potential lockup problem. Besides (1)-(4), we also removed useless void functions, adding the code called from the notifier inside its own body, and changed the priority of such notifiers to execute late, since they are "heavyweight" for the panic environment, so we aim to reduce risks here. Changed return values to NOTIFY_DONE as well, the standard one. Signed-off-by: Guilherme G. Piccoli <gpiccoli@igalia.com> Link: https://lore.kernel.org/r/20220427224924.592546-14-gpiccoli@igalia.com Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
850 lines
22 KiB
C
850 lines
22 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* SCLP VT220 terminal driver.
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*
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* Copyright IBM Corp. 2003, 2009
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*
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* Author(s): Peter Oberparleiter <Peter.Oberparleiter@de.ibm.com>
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*/
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#include <linux/module.h>
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#include <linux/spinlock.h>
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#include <linux/panic_notifier.h>
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#include <linux/list.h>
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#include <linux/wait.h>
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#include <linux/timer.h>
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#include <linux/kernel.h>
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#include <linux/sysrq.h>
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#include <linux/tty.h>
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#include <linux/tty_driver.h>
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#include <linux/tty_flip.h>
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#include <linux/errno.h>
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#include <linux/mm.h>
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#include <linux/major.h>
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#include <linux/console.h>
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#include <linux/kdev_t.h>
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#include <linux/interrupt.h>
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#include <linux/init.h>
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#include <linux/reboot.h>
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#include <linux/slab.h>
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#include <linux/uaccess.h>
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#include "sclp.h"
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#include "ctrlchar.h"
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#define SCLP_VT220_MAJOR TTY_MAJOR
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#define SCLP_VT220_MINOR 65
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#define SCLP_VT220_DRIVER_NAME "sclp_vt220"
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#define SCLP_VT220_DEVICE_NAME "ttysclp"
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#define SCLP_VT220_CONSOLE_NAME "ttysclp"
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#define SCLP_VT220_CONSOLE_INDEX 0 /* console=ttysclp0 */
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/* Representation of a single write request */
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struct sclp_vt220_request {
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struct list_head list;
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struct sclp_req sclp_req;
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int retry_count;
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};
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/* VT220 SCCB */
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struct sclp_vt220_sccb {
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struct sccb_header header;
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struct evbuf_header evbuf;
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};
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#define SCLP_VT220_MAX_CHARS_PER_BUFFER (PAGE_SIZE - \
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sizeof(struct sclp_vt220_request) - \
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sizeof(struct sclp_vt220_sccb))
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/* Structures and data needed to register tty driver */
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static struct tty_driver *sclp_vt220_driver;
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static struct tty_port sclp_vt220_port;
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/* Lock to protect internal data from concurrent access */
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static DEFINE_SPINLOCK(sclp_vt220_lock);
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/* List of empty pages to be used as write request buffers */
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static LIST_HEAD(sclp_vt220_empty);
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/* List of pending requests */
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static LIST_HEAD(sclp_vt220_outqueue);
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/* Flag that output queue is currently running */
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static int sclp_vt220_queue_running;
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/* Timer used for delaying write requests to merge subsequent messages into
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* a single buffer */
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static struct timer_list sclp_vt220_timer;
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/* Pointer to current request buffer which has been partially filled but not
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* yet sent */
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static struct sclp_vt220_request *sclp_vt220_current_request;
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/* Number of characters in current request buffer */
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static int sclp_vt220_buffered_chars;
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/* Counter controlling core driver initialization. */
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static int __initdata sclp_vt220_init_count;
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/* Flag indicating that sclp_vt220_current_request should really
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* have been already queued but wasn't because the SCLP was processing
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* another buffer */
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static int sclp_vt220_flush_later;
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static void sclp_vt220_receiver_fn(struct evbuf_header *evbuf);
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static int __sclp_vt220_emit(struct sclp_vt220_request *request);
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static void sclp_vt220_emit_current(void);
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/* Registration structure for SCLP output event buffers */
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static struct sclp_register sclp_vt220_register = {
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.send_mask = EVTYP_VT220MSG_MASK,
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};
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/* Registration structure for SCLP input event buffers */
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static struct sclp_register sclp_vt220_register_input = {
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.receive_mask = EVTYP_VT220MSG_MASK,
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.receiver_fn = sclp_vt220_receiver_fn,
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};
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/*
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* Put provided request buffer back into queue and check emit pending
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* buffers if necessary.
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*/
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static void
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sclp_vt220_process_queue(struct sclp_vt220_request *request)
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{
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unsigned long flags;
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void *page;
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do {
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/* Put buffer back to list of empty buffers */
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page = request->sclp_req.sccb;
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spin_lock_irqsave(&sclp_vt220_lock, flags);
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/* Move request from outqueue to empty queue */
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list_del(&request->list);
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list_add_tail((struct list_head *) page, &sclp_vt220_empty);
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/* Check if there is a pending buffer on the out queue. */
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request = NULL;
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if (!list_empty(&sclp_vt220_outqueue))
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request = list_entry(sclp_vt220_outqueue.next,
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struct sclp_vt220_request, list);
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if (!request) {
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sclp_vt220_queue_running = 0;
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spin_unlock_irqrestore(&sclp_vt220_lock, flags);
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break;
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}
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spin_unlock_irqrestore(&sclp_vt220_lock, flags);
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} while (__sclp_vt220_emit(request));
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if (request == NULL && sclp_vt220_flush_later)
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sclp_vt220_emit_current();
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tty_port_tty_wakeup(&sclp_vt220_port);
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}
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#define SCLP_BUFFER_MAX_RETRY 1
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/*
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* Callback through which the result of a write request is reported by the
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* SCLP.
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*/
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static void
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sclp_vt220_callback(struct sclp_req *request, void *data)
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{
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struct sclp_vt220_request *vt220_request;
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struct sclp_vt220_sccb *sccb;
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vt220_request = (struct sclp_vt220_request *) data;
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if (request->status == SCLP_REQ_FAILED) {
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sclp_vt220_process_queue(vt220_request);
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return;
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}
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sccb = (struct sclp_vt220_sccb *) vt220_request->sclp_req.sccb;
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/* Check SCLP response code and choose suitable action */
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switch (sccb->header.response_code) {
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case 0x0020 :
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break;
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case 0x05f0: /* Target resource in improper state */
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break;
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case 0x0340: /* Contained SCLP equipment check */
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if (++vt220_request->retry_count > SCLP_BUFFER_MAX_RETRY)
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break;
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/* Remove processed buffers and requeue rest */
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if (sclp_remove_processed((struct sccb_header *) sccb) > 0) {
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/* Not all buffers were processed */
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sccb->header.response_code = 0x0000;
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vt220_request->sclp_req.status = SCLP_REQ_FILLED;
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if (sclp_add_request(request) == 0)
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return;
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}
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break;
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case 0x0040: /* SCLP equipment check */
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if (++vt220_request->retry_count > SCLP_BUFFER_MAX_RETRY)
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break;
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sccb->header.response_code = 0x0000;
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vt220_request->sclp_req.status = SCLP_REQ_FILLED;
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if (sclp_add_request(request) == 0)
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return;
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break;
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default:
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break;
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}
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sclp_vt220_process_queue(vt220_request);
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}
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/*
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* Emit vt220 request buffer to SCLP. Return zero on success, non-zero
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* otherwise.
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*/
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static int
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__sclp_vt220_emit(struct sclp_vt220_request *request)
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{
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request->sclp_req.command = SCLP_CMDW_WRITE_EVENT_DATA;
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request->sclp_req.status = SCLP_REQ_FILLED;
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request->sclp_req.callback = sclp_vt220_callback;
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request->sclp_req.callback_data = (void *) request;
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return sclp_add_request(&request->sclp_req);
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}
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/*
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* Queue and emit current request.
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*/
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static void
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sclp_vt220_emit_current(void)
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{
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unsigned long flags;
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struct sclp_vt220_request *request;
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struct sclp_vt220_sccb *sccb;
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spin_lock_irqsave(&sclp_vt220_lock, flags);
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if (sclp_vt220_current_request) {
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sccb = (struct sclp_vt220_sccb *)
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sclp_vt220_current_request->sclp_req.sccb;
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/* Only emit buffers with content */
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if (sccb->header.length != sizeof(struct sclp_vt220_sccb)) {
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list_add_tail(&sclp_vt220_current_request->list,
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&sclp_vt220_outqueue);
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sclp_vt220_current_request = NULL;
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del_timer(&sclp_vt220_timer);
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}
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sclp_vt220_flush_later = 0;
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}
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if (sclp_vt220_queue_running)
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goto out_unlock;
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if (list_empty(&sclp_vt220_outqueue))
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goto out_unlock;
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request = list_first_entry(&sclp_vt220_outqueue,
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struct sclp_vt220_request, list);
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sclp_vt220_queue_running = 1;
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spin_unlock_irqrestore(&sclp_vt220_lock, flags);
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if (__sclp_vt220_emit(request))
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sclp_vt220_process_queue(request);
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return;
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out_unlock:
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spin_unlock_irqrestore(&sclp_vt220_lock, flags);
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}
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#define SCLP_NORMAL_WRITE 0x00
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/*
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* Helper function to initialize a page with the sclp request structure.
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*/
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static struct sclp_vt220_request *
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sclp_vt220_initialize_page(void *page)
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{
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struct sclp_vt220_request *request;
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struct sclp_vt220_sccb *sccb;
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/* Place request structure at end of page */
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request = ((struct sclp_vt220_request *)
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((addr_t) page + PAGE_SIZE)) - 1;
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request->retry_count = 0;
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request->sclp_req.sccb = page;
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/* SCCB goes at start of page */
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sccb = (struct sclp_vt220_sccb *) page;
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memset((void *) sccb, 0, sizeof(struct sclp_vt220_sccb));
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sccb->header.length = sizeof(struct sclp_vt220_sccb);
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sccb->header.function_code = SCLP_NORMAL_WRITE;
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sccb->header.response_code = 0x0000;
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sccb->evbuf.type = EVTYP_VT220MSG;
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sccb->evbuf.length = sizeof(struct evbuf_header);
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return request;
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}
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static inline unsigned int
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sclp_vt220_space_left(struct sclp_vt220_request *request)
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{
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struct sclp_vt220_sccb *sccb;
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sccb = (struct sclp_vt220_sccb *) request->sclp_req.sccb;
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return PAGE_SIZE - sizeof(struct sclp_vt220_request) -
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sccb->header.length;
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}
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static inline unsigned int
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sclp_vt220_chars_stored(struct sclp_vt220_request *request)
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{
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struct sclp_vt220_sccb *sccb;
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sccb = (struct sclp_vt220_sccb *) request->sclp_req.sccb;
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return sccb->evbuf.length - sizeof(struct evbuf_header);
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}
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/*
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* Add msg to buffer associated with request. Return the number of characters
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* added.
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*/
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static int
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sclp_vt220_add_msg(struct sclp_vt220_request *request,
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const unsigned char *msg, int count, int convertlf)
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{
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struct sclp_vt220_sccb *sccb;
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void *buffer;
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unsigned char c;
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int from;
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int to;
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if (count > sclp_vt220_space_left(request))
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count = sclp_vt220_space_left(request);
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if (count <= 0)
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return 0;
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sccb = (struct sclp_vt220_sccb *) request->sclp_req.sccb;
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buffer = (void *) ((addr_t) sccb + sccb->header.length);
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if (convertlf) {
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/* Perform Linefeed conversion (0x0a -> 0x0a 0x0d)*/
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for (from=0, to=0;
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(from < count) && (to < sclp_vt220_space_left(request));
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from++) {
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/* Retrieve character */
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c = msg[from];
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/* Perform conversion */
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if (c == 0x0a) {
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if (to + 1 < sclp_vt220_space_left(request)) {
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((unsigned char *) buffer)[to++] = c;
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((unsigned char *) buffer)[to++] = 0x0d;
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} else
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break;
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} else
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((unsigned char *) buffer)[to++] = c;
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}
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sccb->header.length += to;
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sccb->evbuf.length += to;
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return from;
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} else {
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memcpy(buffer, (const void *) msg, count);
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sccb->header.length += count;
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sccb->evbuf.length += count;
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return count;
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}
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}
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/*
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* Emit buffer after having waited long enough for more data to arrive.
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*/
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static void
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sclp_vt220_timeout(struct timer_list *unused)
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{
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sclp_vt220_emit_current();
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}
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#define BUFFER_MAX_DELAY HZ/20
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/*
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* Drop oldest console buffer if sclp_con_drop is set
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*/
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static int
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sclp_vt220_drop_buffer(void)
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{
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struct list_head *list;
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struct sclp_vt220_request *request;
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void *page;
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if (!sclp_console_drop)
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return 0;
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list = sclp_vt220_outqueue.next;
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if (sclp_vt220_queue_running)
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/* The first element is in I/O */
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list = list->next;
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if (list == &sclp_vt220_outqueue)
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return 0;
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list_del(list);
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request = list_entry(list, struct sclp_vt220_request, list);
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page = request->sclp_req.sccb;
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list_add_tail((struct list_head *) page, &sclp_vt220_empty);
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return 1;
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}
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/*
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* Internal implementation of the write function. Write COUNT bytes of data
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* from memory at BUF
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* to the SCLP interface. In case that the data does not fit into the current
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* write buffer, emit the current one and allocate a new one. If there are no
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* more empty buffers available, wait until one gets emptied. If DO_SCHEDULE
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* is non-zero, the buffer will be scheduled for emitting after a timeout -
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* otherwise the user has to explicitly call the flush function.
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* A non-zero CONVERTLF parameter indicates that 0x0a characters in the message
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* buffer should be converted to 0x0a 0x0d. After completion, return the number
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* of bytes written.
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*/
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static int
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__sclp_vt220_write(const unsigned char *buf, int count, int do_schedule,
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int convertlf, int may_fail)
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{
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unsigned long flags;
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void *page;
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int written;
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int overall_written;
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if (count <= 0)
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return 0;
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overall_written = 0;
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spin_lock_irqsave(&sclp_vt220_lock, flags);
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do {
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/* Create an sclp output buffer if none exists yet */
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if (sclp_vt220_current_request == NULL) {
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if (list_empty(&sclp_vt220_empty))
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sclp_console_full++;
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while (list_empty(&sclp_vt220_empty)) {
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if (may_fail)
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goto out;
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if (sclp_vt220_drop_buffer())
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break;
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spin_unlock_irqrestore(&sclp_vt220_lock, flags);
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sclp_sync_wait();
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spin_lock_irqsave(&sclp_vt220_lock, flags);
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}
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page = (void *) sclp_vt220_empty.next;
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list_del((struct list_head *) page);
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sclp_vt220_current_request =
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sclp_vt220_initialize_page(page);
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}
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/* Try to write the string to the current request buffer */
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written = sclp_vt220_add_msg(sclp_vt220_current_request,
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buf, count, convertlf);
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overall_written += written;
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if (written == count)
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break;
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/*
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* Not all characters could be written to the current
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* output buffer. Emit the buffer, create a new buffer
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* and then output the rest of the string.
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*/
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spin_unlock_irqrestore(&sclp_vt220_lock, flags);
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sclp_vt220_emit_current();
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spin_lock_irqsave(&sclp_vt220_lock, flags);
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buf += written;
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count -= written;
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} while (count > 0);
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/* Setup timer to output current console buffer after some time */
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if (sclp_vt220_current_request != NULL &&
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!timer_pending(&sclp_vt220_timer) && do_schedule) {
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sclp_vt220_timer.expires = jiffies + BUFFER_MAX_DELAY;
|
|
add_timer(&sclp_vt220_timer);
|
|
}
|
|
out:
|
|
spin_unlock_irqrestore(&sclp_vt220_lock, flags);
|
|
return overall_written;
|
|
}
|
|
|
|
/*
|
|
* This routine is called by the kernel to write a series of
|
|
* characters to the tty device. The characters may come from
|
|
* user space or kernel space. This routine will return the
|
|
* number of characters actually accepted for writing.
|
|
*/
|
|
static int
|
|
sclp_vt220_write(struct tty_struct *tty, const unsigned char *buf, int count)
|
|
{
|
|
return __sclp_vt220_write(buf, count, 1, 0, 1);
|
|
}
|
|
|
|
#define SCLP_VT220_SESSION_ENDED 0x01
|
|
#define SCLP_VT220_SESSION_STARTED 0x80
|
|
#define SCLP_VT220_SESSION_DATA 0x00
|
|
|
|
#ifdef CONFIG_MAGIC_SYSRQ
|
|
|
|
static int sysrq_pressed;
|
|
static struct sysrq_work sysrq;
|
|
|
|
static void sclp_vt220_reset_session(void)
|
|
{
|
|
sysrq_pressed = 0;
|
|
}
|
|
|
|
static void sclp_vt220_handle_input(const char *buffer, unsigned int count)
|
|
{
|
|
int i;
|
|
|
|
for (i = 0; i < count; i++) {
|
|
/* Handle magic sys request */
|
|
if (buffer[i] == ('O' ^ 0100)) { /* CTRL-O */
|
|
/*
|
|
* If pressed again, reset sysrq_pressed
|
|
* and flip CTRL-O character
|
|
*/
|
|
sysrq_pressed = !sysrq_pressed;
|
|
if (sysrq_pressed)
|
|
continue;
|
|
} else if (sysrq_pressed) {
|
|
sysrq.key = buffer[i];
|
|
schedule_sysrq_work(&sysrq);
|
|
sysrq_pressed = 0;
|
|
continue;
|
|
}
|
|
tty_insert_flip_char(&sclp_vt220_port, buffer[i], 0);
|
|
}
|
|
}
|
|
|
|
#else
|
|
|
|
static void sclp_vt220_reset_session(void)
|
|
{
|
|
}
|
|
|
|
static void sclp_vt220_handle_input(const char *buffer, unsigned int count)
|
|
{
|
|
tty_insert_flip_string(&sclp_vt220_port, buffer, count);
|
|
}
|
|
|
|
#endif
|
|
|
|
/*
|
|
* Called by the SCLP to report incoming event buffers.
|
|
*/
|
|
static void
|
|
sclp_vt220_receiver_fn(struct evbuf_header *evbuf)
|
|
{
|
|
char *buffer;
|
|
unsigned int count;
|
|
|
|
buffer = (char *) ((addr_t) evbuf + sizeof(struct evbuf_header));
|
|
count = evbuf->length - sizeof(struct evbuf_header);
|
|
|
|
switch (*buffer) {
|
|
case SCLP_VT220_SESSION_ENDED:
|
|
case SCLP_VT220_SESSION_STARTED:
|
|
sclp_vt220_reset_session();
|
|
break;
|
|
case SCLP_VT220_SESSION_DATA:
|
|
/* Send input to line discipline */
|
|
buffer++;
|
|
count--;
|
|
sclp_vt220_handle_input(buffer, count);
|
|
tty_flip_buffer_push(&sclp_vt220_port);
|
|
break;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* This routine is called when a particular tty device is opened.
|
|
*/
|
|
static int
|
|
sclp_vt220_open(struct tty_struct *tty, struct file *filp)
|
|
{
|
|
if (tty->count == 1) {
|
|
tty_port_tty_set(&sclp_vt220_port, tty);
|
|
if (!tty->winsize.ws_row && !tty->winsize.ws_col) {
|
|
tty->winsize.ws_row = 24;
|
|
tty->winsize.ws_col = 80;
|
|
}
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* This routine is called when a particular tty device is closed.
|
|
*/
|
|
static void
|
|
sclp_vt220_close(struct tty_struct *tty, struct file *filp)
|
|
{
|
|
if (tty->count == 1)
|
|
tty_port_tty_set(&sclp_vt220_port, NULL);
|
|
}
|
|
|
|
/*
|
|
* This routine is called by the kernel to write a single
|
|
* character to the tty device. If the kernel uses this routine,
|
|
* it must call the flush_chars() routine (if defined) when it is
|
|
* done stuffing characters into the driver.
|
|
*/
|
|
static int
|
|
sclp_vt220_put_char(struct tty_struct *tty, unsigned char ch)
|
|
{
|
|
return __sclp_vt220_write(&ch, 1, 0, 0, 1);
|
|
}
|
|
|
|
/*
|
|
* This routine is called by the kernel after it has written a
|
|
* series of characters to the tty device using put_char().
|
|
*/
|
|
static void
|
|
sclp_vt220_flush_chars(struct tty_struct *tty)
|
|
{
|
|
if (!sclp_vt220_queue_running)
|
|
sclp_vt220_emit_current();
|
|
else
|
|
sclp_vt220_flush_later = 1;
|
|
}
|
|
|
|
/*
|
|
* This routine returns the numbers of characters the tty driver
|
|
* will accept for queuing to be written. This number is subject
|
|
* to change as output buffers get emptied, or if the output flow
|
|
* control is acted.
|
|
*/
|
|
static unsigned int
|
|
sclp_vt220_write_room(struct tty_struct *tty)
|
|
{
|
|
unsigned long flags;
|
|
struct list_head *l;
|
|
unsigned int count;
|
|
|
|
spin_lock_irqsave(&sclp_vt220_lock, flags);
|
|
count = 0;
|
|
if (sclp_vt220_current_request != NULL)
|
|
count = sclp_vt220_space_left(sclp_vt220_current_request);
|
|
list_for_each(l, &sclp_vt220_empty)
|
|
count += SCLP_VT220_MAX_CHARS_PER_BUFFER;
|
|
spin_unlock_irqrestore(&sclp_vt220_lock, flags);
|
|
return count;
|
|
}
|
|
|
|
/*
|
|
* Return number of buffered chars.
|
|
*/
|
|
static unsigned int
|
|
sclp_vt220_chars_in_buffer(struct tty_struct *tty)
|
|
{
|
|
unsigned long flags;
|
|
struct list_head *l;
|
|
struct sclp_vt220_request *r;
|
|
unsigned int count = 0;
|
|
|
|
spin_lock_irqsave(&sclp_vt220_lock, flags);
|
|
if (sclp_vt220_current_request != NULL)
|
|
count = sclp_vt220_chars_stored(sclp_vt220_current_request);
|
|
list_for_each(l, &sclp_vt220_outqueue) {
|
|
r = list_entry(l, struct sclp_vt220_request, list);
|
|
count += sclp_vt220_chars_stored(r);
|
|
}
|
|
spin_unlock_irqrestore(&sclp_vt220_lock, flags);
|
|
return count;
|
|
}
|
|
|
|
/*
|
|
* Pass on all buffers to the hardware. Return only when there are no more
|
|
* buffers pending.
|
|
*/
|
|
static void
|
|
sclp_vt220_flush_buffer(struct tty_struct *tty)
|
|
{
|
|
sclp_vt220_emit_current();
|
|
}
|
|
|
|
/* Release allocated pages. */
|
|
static void __init __sclp_vt220_free_pages(void)
|
|
{
|
|
struct list_head *page, *p;
|
|
|
|
list_for_each_safe(page, p, &sclp_vt220_empty) {
|
|
list_del(page);
|
|
free_page((unsigned long) page);
|
|
}
|
|
}
|
|
|
|
/* Release memory and unregister from sclp core. Controlled by init counting -
|
|
* only the last invoker will actually perform these actions. */
|
|
static void __init __sclp_vt220_cleanup(void)
|
|
{
|
|
sclp_vt220_init_count--;
|
|
if (sclp_vt220_init_count != 0)
|
|
return;
|
|
sclp_unregister(&sclp_vt220_register);
|
|
__sclp_vt220_free_pages();
|
|
tty_port_destroy(&sclp_vt220_port);
|
|
}
|
|
|
|
/* Allocate buffer pages and register with sclp core. Controlled by init
|
|
* counting - only the first invoker will actually perform these actions. */
|
|
static int __init __sclp_vt220_init(int num_pages)
|
|
{
|
|
void *page;
|
|
int i;
|
|
int rc;
|
|
|
|
sclp_vt220_init_count++;
|
|
if (sclp_vt220_init_count != 1)
|
|
return 0;
|
|
timer_setup(&sclp_vt220_timer, sclp_vt220_timeout, 0);
|
|
tty_port_init(&sclp_vt220_port);
|
|
sclp_vt220_current_request = NULL;
|
|
sclp_vt220_buffered_chars = 0;
|
|
sclp_vt220_flush_later = 0;
|
|
|
|
/* Allocate pages for output buffering */
|
|
rc = -ENOMEM;
|
|
for (i = 0; i < num_pages; i++) {
|
|
page = (void *) get_zeroed_page(GFP_KERNEL | GFP_DMA);
|
|
if (!page)
|
|
goto out;
|
|
list_add_tail(page, &sclp_vt220_empty);
|
|
}
|
|
rc = sclp_register(&sclp_vt220_register);
|
|
out:
|
|
if (rc) {
|
|
__sclp_vt220_free_pages();
|
|
sclp_vt220_init_count--;
|
|
tty_port_destroy(&sclp_vt220_port);
|
|
}
|
|
return rc;
|
|
}
|
|
|
|
static const struct tty_operations sclp_vt220_ops = {
|
|
.open = sclp_vt220_open,
|
|
.close = sclp_vt220_close,
|
|
.write = sclp_vt220_write,
|
|
.put_char = sclp_vt220_put_char,
|
|
.flush_chars = sclp_vt220_flush_chars,
|
|
.write_room = sclp_vt220_write_room,
|
|
.chars_in_buffer = sclp_vt220_chars_in_buffer,
|
|
.flush_buffer = sclp_vt220_flush_buffer,
|
|
};
|
|
|
|
/*
|
|
* Register driver with SCLP and Linux and initialize internal tty structures.
|
|
*/
|
|
static int __init sclp_vt220_tty_init(void)
|
|
{
|
|
struct tty_driver *driver;
|
|
int rc;
|
|
|
|
/* Note: we're not testing for CONSOLE_IS_SCLP here to preserve
|
|
* symmetry between VM and LPAR systems regarding ttyS1. */
|
|
driver = tty_alloc_driver(1, TTY_DRIVER_REAL_RAW);
|
|
if (IS_ERR(driver))
|
|
return PTR_ERR(driver);
|
|
rc = __sclp_vt220_init(MAX_KMEM_PAGES);
|
|
if (rc)
|
|
goto out_driver;
|
|
|
|
driver->driver_name = SCLP_VT220_DRIVER_NAME;
|
|
driver->name = SCLP_VT220_DEVICE_NAME;
|
|
driver->major = SCLP_VT220_MAJOR;
|
|
driver->minor_start = SCLP_VT220_MINOR;
|
|
driver->type = TTY_DRIVER_TYPE_SYSTEM;
|
|
driver->subtype = SYSTEM_TYPE_TTY;
|
|
driver->init_termios = tty_std_termios;
|
|
tty_set_operations(driver, &sclp_vt220_ops);
|
|
tty_port_link_device(&sclp_vt220_port, driver, 0);
|
|
|
|
rc = tty_register_driver(driver);
|
|
if (rc)
|
|
goto out_init;
|
|
rc = sclp_register(&sclp_vt220_register_input);
|
|
if (rc)
|
|
goto out_reg;
|
|
sclp_vt220_driver = driver;
|
|
return 0;
|
|
|
|
out_reg:
|
|
tty_unregister_driver(driver);
|
|
out_init:
|
|
__sclp_vt220_cleanup();
|
|
out_driver:
|
|
tty_driver_kref_put(driver);
|
|
return rc;
|
|
}
|
|
__initcall(sclp_vt220_tty_init);
|
|
|
|
#ifdef CONFIG_SCLP_VT220_CONSOLE
|
|
|
|
static void
|
|
sclp_vt220_con_write(struct console *con, const char *buf, unsigned int count)
|
|
{
|
|
__sclp_vt220_write((const unsigned char *) buf, count, 1, 1, 0);
|
|
}
|
|
|
|
static struct tty_driver *
|
|
sclp_vt220_con_device(struct console *c, int *index)
|
|
{
|
|
*index = 0;
|
|
return sclp_vt220_driver;
|
|
}
|
|
|
|
/*
|
|
* This panic/reboot notifier runs in atomic context, so
|
|
* locking restrictions apply to prevent potential lockups.
|
|
*/
|
|
static int
|
|
sclp_vt220_notify(struct notifier_block *self,
|
|
unsigned long event, void *data)
|
|
{
|
|
unsigned long flags;
|
|
|
|
if (spin_is_locked(&sclp_vt220_lock))
|
|
return NOTIFY_DONE;
|
|
|
|
sclp_vt220_emit_current();
|
|
|
|
spin_lock_irqsave(&sclp_vt220_lock, flags);
|
|
del_timer(&sclp_vt220_timer);
|
|
while (sclp_vt220_queue_running) {
|
|
spin_unlock_irqrestore(&sclp_vt220_lock, flags);
|
|
sclp_sync_wait();
|
|
spin_lock_irqsave(&sclp_vt220_lock, flags);
|
|
}
|
|
spin_unlock_irqrestore(&sclp_vt220_lock, flags);
|
|
|
|
return NOTIFY_DONE;
|
|
}
|
|
|
|
static struct notifier_block on_panic_nb = {
|
|
.notifier_call = sclp_vt220_notify,
|
|
.priority = INT_MIN + 1, /* run the callback late */
|
|
};
|
|
|
|
static struct notifier_block on_reboot_nb = {
|
|
.notifier_call = sclp_vt220_notify,
|
|
.priority = INT_MIN + 1, /* run the callback late */
|
|
};
|
|
|
|
/* Structure needed to register with printk */
|
|
static struct console sclp_vt220_console =
|
|
{
|
|
.name = SCLP_VT220_CONSOLE_NAME,
|
|
.write = sclp_vt220_con_write,
|
|
.device = sclp_vt220_con_device,
|
|
.flags = CON_PRINTBUFFER,
|
|
.index = SCLP_VT220_CONSOLE_INDEX
|
|
};
|
|
|
|
static int __init
|
|
sclp_vt220_con_init(void)
|
|
{
|
|
int rc;
|
|
|
|
rc = __sclp_vt220_init(sclp_console_pages);
|
|
if (rc)
|
|
return rc;
|
|
/* Attach linux console */
|
|
atomic_notifier_chain_register(&panic_notifier_list, &on_panic_nb);
|
|
register_reboot_notifier(&on_reboot_nb);
|
|
register_console(&sclp_vt220_console);
|
|
return 0;
|
|
}
|
|
|
|
console_initcall(sclp_vt220_con_init);
|
|
#endif /* CONFIG_SCLP_VT220_CONSOLE */
|
|
|