linux/drivers/s390/char/sclp.c
Peter Oberparleiter 25fab9ebac [PATCH] s390: fix sclp memory corruption in tty pages list
When the sclp interface takes very long to serve a request, the sclp core
driver will report a failed request to the sclp tty driver even though the
request is still being processed by the sclp interface.  Eventually the sclp
interface completes the request and updates some fields in the request buffer
which leads to a corrupted tty pages list.  The next time function
sclp_tty_write_room is called, the corrupted list will be traversed, resulting
in an oops.

To avoid this remove the busy retry limit and increase retry intervals.

Signed-off-by: Peter Oberparleiter <peter.oberparleiter@de.ibm.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-02-11 21:41:12 -08:00

912 lines
25 KiB
C

/*
* drivers/s390/char/sclp.c
* core function to access sclp interface
*
* S390 version
* Copyright (C) 1999 IBM Deutschland Entwicklung GmbH, IBM Corporation
* Author(s): Martin Peschke <mpeschke@de.ibm.com>
* Martin Schwidefsky <schwidefsky@de.ibm.com>
*/
#include <linux/module.h>
#include <linux/err.h>
#include <linux/spinlock.h>
#include <linux/interrupt.h>
#include <linux/timer.h>
#include <linux/reboot.h>
#include <linux/jiffies.h>
#include <asm/types.h>
#include <asm/s390_ext.h>
#include "sclp.h"
#define SCLP_HEADER "sclp: "
/* Structure for register_early_external_interrupt. */
static ext_int_info_t ext_int_info_hwc;
/* Lock to protect internal data consistency. */
static DEFINE_SPINLOCK(sclp_lock);
/* Mask of events that we can receive from the sclp interface. */
static sccb_mask_t sclp_receive_mask;
/* Mask of events that we can send to the sclp interface. */
static sccb_mask_t sclp_send_mask;
/* List of registered event listeners and senders. */
static struct list_head sclp_reg_list;
/* List of queued requests. */
static struct list_head sclp_req_queue;
/* Data for read and and init requests. */
static struct sclp_req sclp_read_req;
static struct sclp_req sclp_init_req;
static char sclp_read_sccb[PAGE_SIZE] __attribute__((__aligned__(PAGE_SIZE)));
static char sclp_init_sccb[PAGE_SIZE] __attribute__((__aligned__(PAGE_SIZE)));
/* Timer for request retries. */
static struct timer_list sclp_request_timer;
/* Internal state: is the driver initialized? */
static volatile enum sclp_init_state_t {
sclp_init_state_uninitialized,
sclp_init_state_initializing,
sclp_init_state_initialized
} sclp_init_state = sclp_init_state_uninitialized;
/* Internal state: is a request active at the sclp? */
static volatile enum sclp_running_state_t {
sclp_running_state_idle,
sclp_running_state_running
} sclp_running_state = sclp_running_state_idle;
/* Internal state: is a read request pending? */
static volatile enum sclp_reading_state_t {
sclp_reading_state_idle,
sclp_reading_state_reading
} sclp_reading_state = sclp_reading_state_idle;
/* Internal state: is the driver currently serving requests? */
static volatile enum sclp_activation_state_t {
sclp_activation_state_active,
sclp_activation_state_deactivating,
sclp_activation_state_inactive,
sclp_activation_state_activating
} sclp_activation_state = sclp_activation_state_active;
/* Internal state: is an init mask request pending? */
static volatile enum sclp_mask_state_t {
sclp_mask_state_idle,
sclp_mask_state_initializing
} sclp_mask_state = sclp_mask_state_idle;
/* Maximum retry counts */
#define SCLP_INIT_RETRY 3
#define SCLP_MASK_RETRY 3
/* Timeout intervals in seconds.*/
#define SCLP_BUSY_INTERVAL 10
#define SCLP_RETRY_INTERVAL 15
static void sclp_process_queue(void);
static int sclp_init_mask(int calculate);
static int sclp_init(void);
/* Perform service call. Return 0 on success, non-zero otherwise. */
static int
service_call(sclp_cmdw_t command, void *sccb)
{
int cc;
__asm__ __volatile__(
" .insn rre,0xb2200000,%1,%2\n" /* servc %1,%2 */
" ipm %0\n"
" srl %0,28"
: "=&d" (cc)
: "d" (command), "a" (__pa(sccb))
: "cc", "memory" );
if (cc == 3)
return -EIO;
if (cc == 2)
return -EBUSY;
return 0;
}
/* Request timeout handler. Restart the request queue. If DATA is non-zero,
* force restart of running request. */
static void
sclp_request_timeout(unsigned long data)
{
unsigned long flags;
if (data) {
spin_lock_irqsave(&sclp_lock, flags);
sclp_running_state = sclp_running_state_idle;
spin_unlock_irqrestore(&sclp_lock, flags);
}
sclp_process_queue();
}
/* Set up request retry timer. Called while sclp_lock is locked. */
static inline void
__sclp_set_request_timer(unsigned long time, void (*function)(unsigned long),
unsigned long data)
{
del_timer(&sclp_request_timer);
sclp_request_timer.function = function;
sclp_request_timer.data = data;
sclp_request_timer.expires = jiffies + time;
add_timer(&sclp_request_timer);
}
/* Try to start a request. Return zero if the request was successfully
* started or if it will be started at a later time. Return non-zero otherwise.
* Called while sclp_lock is locked. */
static int
__sclp_start_request(struct sclp_req *req)
{
int rc;
if (sclp_running_state != sclp_running_state_idle)
return 0;
del_timer(&sclp_request_timer);
rc = service_call(req->command, req->sccb);
req->start_count++;
if (rc == 0) {
/* Sucessfully started request */
req->status = SCLP_REQ_RUNNING;
sclp_running_state = sclp_running_state_running;
__sclp_set_request_timer(SCLP_RETRY_INTERVAL * HZ,
sclp_request_timeout, 1);
return 0;
} else if (rc == -EBUSY) {
/* Try again later */
__sclp_set_request_timer(SCLP_BUSY_INTERVAL * HZ,
sclp_request_timeout, 0);
return 0;
}
/* Request failed */
req->status = SCLP_REQ_FAILED;
return rc;
}
/* Try to start queued requests. */
static void
sclp_process_queue(void)
{
struct sclp_req *req;
int rc;
unsigned long flags;
spin_lock_irqsave(&sclp_lock, flags);
if (sclp_running_state != sclp_running_state_idle) {
spin_unlock_irqrestore(&sclp_lock, flags);
return;
}
del_timer(&sclp_request_timer);
while (!list_empty(&sclp_req_queue)) {
req = list_entry(sclp_req_queue.next, struct sclp_req, list);
rc = __sclp_start_request(req);
if (rc == 0)
break;
/* Request failed. */
list_del(&req->list);
if (req->callback) {
spin_unlock_irqrestore(&sclp_lock, flags);
req->callback(req, req->callback_data);
spin_lock_irqsave(&sclp_lock, flags);
}
}
spin_unlock_irqrestore(&sclp_lock, flags);
}
/* Queue a new request. Return zero on success, non-zero otherwise. */
int
sclp_add_request(struct sclp_req *req)
{
unsigned long flags;
int rc;
spin_lock_irqsave(&sclp_lock, flags);
if ((sclp_init_state != sclp_init_state_initialized ||
sclp_activation_state != sclp_activation_state_active) &&
req != &sclp_init_req) {
spin_unlock_irqrestore(&sclp_lock, flags);
return -EIO;
}
req->status = SCLP_REQ_QUEUED;
req->start_count = 0;
list_add_tail(&req->list, &sclp_req_queue);
rc = 0;
/* Start if request is first in list */
if (req->list.prev == &sclp_req_queue) {
rc = __sclp_start_request(req);
if (rc)
list_del(&req->list);
}
spin_unlock_irqrestore(&sclp_lock, flags);
return rc;
}
EXPORT_SYMBOL(sclp_add_request);
/* Dispatch events found in request buffer to registered listeners. Return 0
* if all events were dispatched, non-zero otherwise. */
static int
sclp_dispatch_evbufs(struct sccb_header *sccb)
{
unsigned long flags;
struct evbuf_header *evbuf;
struct list_head *l;
struct sclp_register *reg;
int offset;
int rc;
spin_lock_irqsave(&sclp_lock, flags);
rc = 0;
for (offset = sizeof(struct sccb_header); offset < sccb->length;
offset += evbuf->length) {
/* Search for event handler */
evbuf = (struct evbuf_header *) ((addr_t) sccb + offset);
reg = NULL;
list_for_each(l, &sclp_reg_list) {
reg = list_entry(l, struct sclp_register, list);
if (reg->receive_mask & (1 << (32 - evbuf->type)))
break;
else
reg = NULL;
}
if (reg && reg->receiver_fn) {
spin_unlock_irqrestore(&sclp_lock, flags);
reg->receiver_fn(evbuf);
spin_lock_irqsave(&sclp_lock, flags);
} else if (reg == NULL)
rc = -ENOSYS;
}
spin_unlock_irqrestore(&sclp_lock, flags);
return rc;
}
/* Read event data request callback. */
static void
sclp_read_cb(struct sclp_req *req, void *data)
{
unsigned long flags;
struct sccb_header *sccb;
sccb = (struct sccb_header *) req->sccb;
if (req->status == SCLP_REQ_DONE && (sccb->response_code == 0x20 ||
sccb->response_code == 0x220))
sclp_dispatch_evbufs(sccb);
spin_lock_irqsave(&sclp_lock, flags);
sclp_reading_state = sclp_reading_state_idle;
spin_unlock_irqrestore(&sclp_lock, flags);
}
/* Prepare read event data request. Called while sclp_lock is locked. */
static inline void
__sclp_make_read_req(void)
{
struct sccb_header *sccb;
sccb = (struct sccb_header *) sclp_read_sccb;
clear_page(sccb);
memset(&sclp_read_req, 0, sizeof(struct sclp_req));
sclp_read_req.command = SCLP_CMDW_READDATA;
sclp_read_req.status = SCLP_REQ_QUEUED;
sclp_read_req.start_count = 0;
sclp_read_req.callback = sclp_read_cb;
sclp_read_req.sccb = sccb;
sccb->length = PAGE_SIZE;
sccb->function_code = 0;
sccb->control_mask[2] = 0x80;
}
/* Search request list for request with matching sccb. Return request if found,
* NULL otherwise. Called while sclp_lock is locked. */
static inline struct sclp_req *
__sclp_find_req(u32 sccb)
{
struct list_head *l;
struct sclp_req *req;
list_for_each(l, &sclp_req_queue) {
req = list_entry(l, struct sclp_req, list);
if (sccb == (u32) (addr_t) req->sccb)
return req;
}
return NULL;
}
/* Handler for external interruption. Perform request post-processing.
* Prepare read event data request if necessary. Start processing of next
* request on queue. */
static void
sclp_interrupt_handler(struct pt_regs *regs, __u16 code)
{
struct sclp_req *req;
u32 finished_sccb;
u32 evbuf_pending;
spin_lock(&sclp_lock);
finished_sccb = S390_lowcore.ext_params & 0xfffffff8;
evbuf_pending = S390_lowcore.ext_params & 0x3;
if (finished_sccb) {
req = __sclp_find_req(finished_sccb);
if (req) {
/* Request post-processing */
list_del(&req->list);
req->status = SCLP_REQ_DONE;
if (req->callback) {
spin_unlock(&sclp_lock);
req->callback(req, req->callback_data);
spin_lock(&sclp_lock);
}
}
sclp_running_state = sclp_running_state_idle;
}
if (evbuf_pending && sclp_receive_mask != 0 &&
sclp_reading_state == sclp_reading_state_idle &&
sclp_activation_state == sclp_activation_state_active ) {
sclp_reading_state = sclp_reading_state_reading;
__sclp_make_read_req();
/* Add request to head of queue */
list_add(&sclp_read_req.list, &sclp_req_queue);
}
spin_unlock(&sclp_lock);
sclp_process_queue();
}
/* Return current Time-Of-Day clock. */
static inline u64
sclp_get_clock(void)
{
u64 result;
asm volatile ("STCK 0(%1)" : "=m" (result) : "a" (&(result)) : "cc");
return result;
}
/* Convert interval in jiffies to TOD ticks. */
static inline u64
sclp_tod_from_jiffies(unsigned long jiffies)
{
return (u64) (jiffies / HZ) << 32;
}
/* Wait until a currently running request finished. Note: while this function
* is running, no timers are served on the calling CPU. */
void
sclp_sync_wait(void)
{
unsigned long psw_mask;
unsigned long cr0, cr0_sync;
u64 timeout;
/* We'll be disabling timer interrupts, so we need a custom timeout
* mechanism */
timeout = 0;
if (timer_pending(&sclp_request_timer)) {
/* Get timeout TOD value */
timeout = sclp_get_clock() +
sclp_tod_from_jiffies(sclp_request_timer.expires -
jiffies);
}
/* Prevent bottom half from executing once we force interrupts open */
local_bh_disable();
/* Enable service-signal interruption, disable timer interrupts */
__ctl_store(cr0, 0, 0);
cr0_sync = cr0;
cr0_sync |= 0x00000200;
cr0_sync &= 0xFFFFF3AC;
__ctl_load(cr0_sync, 0, 0);
asm volatile ("STOSM 0(%1),0x01"
: "=m" (psw_mask) : "a" (&psw_mask) : "memory");
/* Loop until driver state indicates finished request */
while (sclp_running_state != sclp_running_state_idle) {
/* Check for expired request timer */
if (timer_pending(&sclp_request_timer) &&
sclp_get_clock() > timeout &&
del_timer(&sclp_request_timer))
sclp_request_timer.function(sclp_request_timer.data);
barrier();
cpu_relax();
}
/* Restore interrupt settings */
asm volatile ("SSM 0(%0)"
: : "a" (&psw_mask) : "memory");
__ctl_load(cr0, 0, 0);
__local_bh_enable();
}
EXPORT_SYMBOL(sclp_sync_wait);
/* Dispatch changes in send and receive mask to registered listeners. */
static inline void
sclp_dispatch_state_change(void)
{
struct list_head *l;
struct sclp_register *reg;
unsigned long flags;
sccb_mask_t receive_mask;
sccb_mask_t send_mask;
do {
spin_lock_irqsave(&sclp_lock, flags);
reg = NULL;
list_for_each(l, &sclp_reg_list) {
reg = list_entry(l, struct sclp_register, list);
receive_mask = reg->receive_mask & sclp_receive_mask;
send_mask = reg->send_mask & sclp_send_mask;
if (reg->sclp_receive_mask != receive_mask ||
reg->sclp_send_mask != send_mask) {
reg->sclp_receive_mask = receive_mask;
reg->sclp_send_mask = send_mask;
break;
} else
reg = NULL;
}
spin_unlock_irqrestore(&sclp_lock, flags);
if (reg && reg->state_change_fn)
reg->state_change_fn(reg);
} while (reg);
}
struct sclp_statechangebuf {
struct evbuf_header header;
u8 validity_sclp_active_facility_mask : 1;
u8 validity_sclp_receive_mask : 1;
u8 validity_sclp_send_mask : 1;
u8 validity_read_data_function_mask : 1;
u16 _zeros : 12;
u16 mask_length;
u64 sclp_active_facility_mask;
sccb_mask_t sclp_receive_mask;
sccb_mask_t sclp_send_mask;
u32 read_data_function_mask;
} __attribute__((packed));
/* State change event callback. Inform listeners of changes. */
static void
sclp_state_change_cb(struct evbuf_header *evbuf)
{
unsigned long flags;
struct sclp_statechangebuf *scbuf;
scbuf = (struct sclp_statechangebuf *) evbuf;
if (scbuf->mask_length != sizeof(sccb_mask_t))
return;
spin_lock_irqsave(&sclp_lock, flags);
if (scbuf->validity_sclp_receive_mask)
sclp_receive_mask = scbuf->sclp_receive_mask;
if (scbuf->validity_sclp_send_mask)
sclp_send_mask = scbuf->sclp_send_mask;
spin_unlock_irqrestore(&sclp_lock, flags);
sclp_dispatch_state_change();
}
static struct sclp_register sclp_state_change_event = {
.receive_mask = EvTyp_StateChange_Mask,
.receiver_fn = sclp_state_change_cb
};
/* Calculate receive and send mask of currently registered listeners.
* Called while sclp_lock is locked. */
static inline void
__sclp_get_mask(sccb_mask_t *receive_mask, sccb_mask_t *send_mask)
{
struct list_head *l;
struct sclp_register *t;
*receive_mask = 0;
*send_mask = 0;
list_for_each(l, &sclp_reg_list) {
t = list_entry(l, struct sclp_register, list);
*receive_mask |= t->receive_mask;
*send_mask |= t->send_mask;
}
}
/* Register event listener. Return 0 on success, non-zero otherwise. */
int
sclp_register(struct sclp_register *reg)
{
unsigned long flags;
sccb_mask_t receive_mask;
sccb_mask_t send_mask;
int rc;
rc = sclp_init();
if (rc)
return rc;
spin_lock_irqsave(&sclp_lock, flags);
/* Check event mask for collisions */
__sclp_get_mask(&receive_mask, &send_mask);
if (reg->receive_mask & receive_mask || reg->send_mask & send_mask) {
spin_unlock_irqrestore(&sclp_lock, flags);
return -EBUSY;
}
/* Trigger initial state change callback */
reg->sclp_receive_mask = 0;
reg->sclp_send_mask = 0;
list_add(&reg->list, &sclp_reg_list);
spin_unlock_irqrestore(&sclp_lock, flags);
rc = sclp_init_mask(1);
if (rc) {
spin_lock_irqsave(&sclp_lock, flags);
list_del(&reg->list);
spin_unlock_irqrestore(&sclp_lock, flags);
}
return rc;
}
EXPORT_SYMBOL(sclp_register);
/* Unregister event listener. */
void
sclp_unregister(struct sclp_register *reg)
{
unsigned long flags;
spin_lock_irqsave(&sclp_lock, flags);
list_del(&reg->list);
spin_unlock_irqrestore(&sclp_lock, flags);
sclp_init_mask(1);
}
EXPORT_SYMBOL(sclp_unregister);
/* Remove event buffers which are marked processed. Return the number of
* remaining event buffers. */
int
sclp_remove_processed(struct sccb_header *sccb)
{
struct evbuf_header *evbuf;
int unprocessed;
u16 remaining;
evbuf = (struct evbuf_header *) (sccb + 1);
unprocessed = 0;
remaining = sccb->length - sizeof(struct sccb_header);
while (remaining > 0) {
remaining -= evbuf->length;
if (evbuf->flags & 0x80) {
sccb->length -= evbuf->length;
memcpy(evbuf, (void *) ((addr_t) evbuf + evbuf->length),
remaining);
} else {
unprocessed++;
evbuf = (struct evbuf_header *)
((addr_t) evbuf + evbuf->length);
}
}
return unprocessed;
}
EXPORT_SYMBOL(sclp_remove_processed);
struct init_sccb {
struct sccb_header header;
u16 _reserved;
u16 mask_length;
sccb_mask_t receive_mask;
sccb_mask_t send_mask;
sccb_mask_t sclp_send_mask;
sccb_mask_t sclp_receive_mask;
} __attribute__((packed));
/* Prepare init mask request. Called while sclp_lock is locked. */
static inline void
__sclp_make_init_req(u32 receive_mask, u32 send_mask)
{
struct init_sccb *sccb;
sccb = (struct init_sccb *) sclp_init_sccb;
clear_page(sccb);
memset(&sclp_init_req, 0, sizeof(struct sclp_req));
sclp_init_req.command = SCLP_CMDW_WRITEMASK;
sclp_init_req.status = SCLP_REQ_FILLED;
sclp_init_req.start_count = 0;
sclp_init_req.callback = NULL;
sclp_init_req.callback_data = NULL;
sclp_init_req.sccb = sccb;
sccb->header.length = sizeof(struct init_sccb);
sccb->mask_length = sizeof(sccb_mask_t);
sccb->receive_mask = receive_mask;
sccb->send_mask = send_mask;
sccb->sclp_receive_mask = 0;
sccb->sclp_send_mask = 0;
}
/* Start init mask request. If calculate is non-zero, calculate the mask as
* requested by registered listeners. Use zero mask otherwise. Return 0 on
* success, non-zero otherwise. */
static int
sclp_init_mask(int calculate)
{
unsigned long flags;
struct init_sccb *sccb = (struct init_sccb *) sclp_init_sccb;
sccb_mask_t receive_mask;
sccb_mask_t send_mask;
int retry;
int rc;
unsigned long wait;
spin_lock_irqsave(&sclp_lock, flags);
/* Check if interface is in appropriate state */
if (sclp_mask_state != sclp_mask_state_idle) {
spin_unlock_irqrestore(&sclp_lock, flags);
return -EBUSY;
}
if (sclp_activation_state == sclp_activation_state_inactive) {
spin_unlock_irqrestore(&sclp_lock, flags);
return -EINVAL;
}
sclp_mask_state = sclp_mask_state_initializing;
/* Determine mask */
if (calculate)
__sclp_get_mask(&receive_mask, &send_mask);
else {
receive_mask = 0;
send_mask = 0;
}
rc = -EIO;
for (retry = 0; retry <= SCLP_MASK_RETRY; retry++) {
/* Prepare request */
__sclp_make_init_req(receive_mask, send_mask);
spin_unlock_irqrestore(&sclp_lock, flags);
if (sclp_add_request(&sclp_init_req)) {
/* Try again later */
wait = jiffies + SCLP_BUSY_INTERVAL * HZ;
while (time_before(jiffies, wait))
sclp_sync_wait();
spin_lock_irqsave(&sclp_lock, flags);
continue;
}
while (sclp_init_req.status != SCLP_REQ_DONE &&
sclp_init_req.status != SCLP_REQ_FAILED)
sclp_sync_wait();
spin_lock_irqsave(&sclp_lock, flags);
if (sclp_init_req.status == SCLP_REQ_DONE &&
sccb->header.response_code == 0x20) {
/* Successful request */
if (calculate) {
sclp_receive_mask = sccb->sclp_receive_mask;
sclp_send_mask = sccb->sclp_send_mask;
} else {
sclp_receive_mask = 0;
sclp_send_mask = 0;
}
spin_unlock_irqrestore(&sclp_lock, flags);
sclp_dispatch_state_change();
spin_lock_irqsave(&sclp_lock, flags);
rc = 0;
break;
}
}
sclp_mask_state = sclp_mask_state_idle;
spin_unlock_irqrestore(&sclp_lock, flags);
return rc;
}
/* Deactivate SCLP interface. On success, new requests will be rejected,
* events will no longer be dispatched. Return 0 on success, non-zero
* otherwise. */
int
sclp_deactivate(void)
{
unsigned long flags;
int rc;
spin_lock_irqsave(&sclp_lock, flags);
/* Deactivate can only be called when active */
if (sclp_activation_state != sclp_activation_state_active) {
spin_unlock_irqrestore(&sclp_lock, flags);
return -EINVAL;
}
sclp_activation_state = sclp_activation_state_deactivating;
spin_unlock_irqrestore(&sclp_lock, flags);
rc = sclp_init_mask(0);
spin_lock_irqsave(&sclp_lock, flags);
if (rc == 0)
sclp_activation_state = sclp_activation_state_inactive;
else
sclp_activation_state = sclp_activation_state_active;
spin_unlock_irqrestore(&sclp_lock, flags);
return rc;
}
EXPORT_SYMBOL(sclp_deactivate);
/* Reactivate SCLP interface after sclp_deactivate. On success, new
* requests will be accepted, events will be dispatched again. Return 0 on
* success, non-zero otherwise. */
int
sclp_reactivate(void)
{
unsigned long flags;
int rc;
spin_lock_irqsave(&sclp_lock, flags);
/* Reactivate can only be called when inactive */
if (sclp_activation_state != sclp_activation_state_inactive) {
spin_unlock_irqrestore(&sclp_lock, flags);
return -EINVAL;
}
sclp_activation_state = sclp_activation_state_activating;
spin_unlock_irqrestore(&sclp_lock, flags);
rc = sclp_init_mask(1);
spin_lock_irqsave(&sclp_lock, flags);
if (rc == 0)
sclp_activation_state = sclp_activation_state_active;
else
sclp_activation_state = sclp_activation_state_inactive;
spin_unlock_irqrestore(&sclp_lock, flags);
return rc;
}
EXPORT_SYMBOL(sclp_reactivate);
/* Handler for external interruption used during initialization. Modify
* request state to done. */
static void
sclp_check_handler(struct pt_regs *regs, __u16 code)
{
u32 finished_sccb;
finished_sccb = S390_lowcore.ext_params & 0xfffffff8;
/* Is this the interrupt we are waiting for? */
if (finished_sccb == 0)
return;
if (finished_sccb != (u32) (addr_t) sclp_init_sccb) {
printk(KERN_WARNING SCLP_HEADER "unsolicited interrupt "
"for buffer at 0x%x\n", finished_sccb);
return;
}
spin_lock(&sclp_lock);
if (sclp_running_state == sclp_running_state_running) {
sclp_init_req.status = SCLP_REQ_DONE;
sclp_running_state = sclp_running_state_idle;
}
spin_unlock(&sclp_lock);
}
/* Initial init mask request timed out. Modify request state to failed. */
static void
sclp_check_timeout(unsigned long data)
{
unsigned long flags;
spin_lock_irqsave(&sclp_lock, flags);
if (sclp_running_state == sclp_running_state_running) {
sclp_init_req.status = SCLP_REQ_FAILED;
sclp_running_state = sclp_running_state_idle;
}
spin_unlock_irqrestore(&sclp_lock, flags);
}
/* Perform a check of the SCLP interface. Return zero if the interface is
* available and there are no pending requests from a previous instance.
* Return non-zero otherwise. */
static int
sclp_check_interface(void)
{
struct init_sccb *sccb;
unsigned long flags;
int retry;
int rc;
spin_lock_irqsave(&sclp_lock, flags);
/* Prepare init mask command */
rc = register_early_external_interrupt(0x2401, sclp_check_handler,
&ext_int_info_hwc);
if (rc) {
spin_unlock_irqrestore(&sclp_lock, flags);
return rc;
}
for (retry = 0; retry <= SCLP_INIT_RETRY; retry++) {
__sclp_make_init_req(0, 0);
sccb = (struct init_sccb *) sclp_init_req.sccb;
rc = service_call(sclp_init_req.command, sccb);
if (rc == -EIO)
break;
sclp_init_req.status = SCLP_REQ_RUNNING;
sclp_running_state = sclp_running_state_running;
__sclp_set_request_timer(SCLP_RETRY_INTERVAL * HZ,
sclp_check_timeout, 0);
spin_unlock_irqrestore(&sclp_lock, flags);
/* Enable service-signal interruption - needs to happen
* with IRQs enabled. */
ctl_set_bit(0, 9);
/* Wait for signal from interrupt or timeout */
sclp_sync_wait();
/* Disable service-signal interruption - needs to happen
* with IRQs enabled. */
ctl_clear_bit(0,9);
spin_lock_irqsave(&sclp_lock, flags);
del_timer(&sclp_request_timer);
if (sclp_init_req.status == SCLP_REQ_DONE &&
sccb->header.response_code == 0x20) {
rc = 0;
break;
} else
rc = -EBUSY;
}
unregister_early_external_interrupt(0x2401, sclp_check_handler,
&ext_int_info_hwc);
spin_unlock_irqrestore(&sclp_lock, flags);
return rc;
}
/* Reboot event handler. Reset send and receive mask to prevent pending SCLP
* events from interfering with rebooted system. */
static int
sclp_reboot_event(struct notifier_block *this, unsigned long event, void *ptr)
{
sclp_deactivate();
return NOTIFY_DONE;
}
static struct notifier_block sclp_reboot_notifier = {
.notifier_call = sclp_reboot_event
};
/* Initialize SCLP driver. Return zero if driver is operational, non-zero
* otherwise. */
static int
sclp_init(void)
{
unsigned long flags;
int rc;
if (!MACHINE_HAS_SCLP)
return -ENODEV;
spin_lock_irqsave(&sclp_lock, flags);
/* Check for previous or running initialization */
if (sclp_init_state != sclp_init_state_uninitialized) {
spin_unlock_irqrestore(&sclp_lock, flags);
return 0;
}
sclp_init_state = sclp_init_state_initializing;
/* Set up variables */
INIT_LIST_HEAD(&sclp_req_queue);
INIT_LIST_HEAD(&sclp_reg_list);
list_add(&sclp_state_change_event.list, &sclp_reg_list);
init_timer(&sclp_request_timer);
/* Check interface */
spin_unlock_irqrestore(&sclp_lock, flags);
rc = sclp_check_interface();
spin_lock_irqsave(&sclp_lock, flags);
if (rc) {
sclp_init_state = sclp_init_state_uninitialized;
spin_unlock_irqrestore(&sclp_lock, flags);
return rc;
}
/* Register reboot handler */
rc = register_reboot_notifier(&sclp_reboot_notifier);
if (rc) {
sclp_init_state = sclp_init_state_uninitialized;
spin_unlock_irqrestore(&sclp_lock, flags);
return rc;
}
/* Register interrupt handler */
rc = register_early_external_interrupt(0x2401, sclp_interrupt_handler,
&ext_int_info_hwc);
if (rc) {
unregister_reboot_notifier(&sclp_reboot_notifier);
sclp_init_state = sclp_init_state_uninitialized;
spin_unlock_irqrestore(&sclp_lock, flags);
return rc;
}
sclp_init_state = sclp_init_state_initialized;
spin_unlock_irqrestore(&sclp_lock, flags);
/* Enable service-signal external interruption - needs to happen with
* IRQs enabled. */
ctl_set_bit(0, 9);
sclp_init_mask(1);
return 0;
}