diff options
Diffstat (limited to 'drivers/s390/char/sclp.c')
| -rw-r--r-- | drivers/s390/char/sclp.c | 1315 |
1 files changed, 1315 insertions, 0 deletions
diff --git a/drivers/s390/char/sclp.c b/drivers/s390/char/sclp.c new file mode 100644 index 0000000000..8f74db689a --- /dev/null +++ b/drivers/s390/char/sclp.c @@ -0,0 +1,1315 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * core function to access sclp interface + * + * Copyright IBM Corp. 1999, 2009 + * + * Author(s): Martin Peschke <mpeschke@de.ibm.com> + * Martin Schwidefsky <schwidefsky@de.ibm.com> + */ + +#include <linux/kernel_stat.h> +#include <linux/module.h> +#include <linux/err.h> +#include <linux/panic_notifier.h> +#include <linux/spinlock.h> +#include <linux/interrupt.h> +#include <linux/timer.h> +#include <linux/reboot.h> +#include <linux/jiffies.h> +#include <linux/init.h> +#include <linux/platform_device.h> +#include <asm/types.h> +#include <asm/irq.h> +#include <asm/debug.h> + +#include "sclp.h" + +#define SCLP_HEADER "sclp: " + +struct sclp_trace_entry { + char id[4] __nonstring; + u32 a; + u64 b; +}; + +#define SCLP_TRACE_ENTRY_SIZE sizeof(struct sclp_trace_entry) +#define SCLP_TRACE_MAX_SIZE 128 +#define SCLP_TRACE_EVENT_MAX_SIZE 64 + +/* Debug trace area intended for all entries in abbreviated form. */ +DEFINE_STATIC_DEBUG_INFO(sclp_debug, "sclp", 8, 1, SCLP_TRACE_ENTRY_SIZE, + &debug_hex_ascii_view); + +/* Error trace area intended for full entries relating to failed requests. */ +DEFINE_STATIC_DEBUG_INFO(sclp_debug_err, "sclp_err", 4, 1, + SCLP_TRACE_ENTRY_SIZE, &debug_hex_ascii_view); + +/* Lock to protect internal data consistency. */ +static DEFINE_SPINLOCK(sclp_lock); + +/* Mask of events that we can send to the sclp interface. */ +static sccb_mask_t sclp_receive_mask; + +/* Mask of events that we can receive from the sclp interface. */ +static sccb_mask_t sclp_send_mask; + +/* List of registered event listeners and senders. */ +static LIST_HEAD(sclp_reg_list); + +/* List of queued requests. */ +static LIST_HEAD(sclp_req_queue); + +/* Data for read and init requests. */ +static struct sclp_req sclp_read_req; +static struct sclp_req sclp_init_req; +static void *sclp_read_sccb; +static struct init_sccb *sclp_init_sccb; + +/* Number of console pages to allocate, used by sclp_con.c and sclp_vt220.c */ +int sclp_console_pages = SCLP_CONSOLE_PAGES; +/* Flag to indicate if buffer pages are dropped on buffer full condition */ +bool sclp_console_drop = true; +/* Number of times the console dropped buffer pages */ +unsigned long sclp_console_full; + +/* The currently active SCLP command word. */ +static sclp_cmdw_t active_cmd; + +static inline void sclp_trace(int prio, char *id, u32 a, u64 b, bool err) +{ + struct sclp_trace_entry e; + + memset(&e, 0, sizeof(e)); + strncpy(e.id, id, sizeof(e.id)); + e.a = a; + e.b = b; + debug_event(&sclp_debug, prio, &e, sizeof(e)); + if (err) + debug_event(&sclp_debug_err, 0, &e, sizeof(e)); +} + +static inline int no_zeroes_len(void *data, int len) +{ + char *d = data; + + /* Minimize trace area usage by not tracing trailing zeroes. */ + while (len > SCLP_TRACE_ENTRY_SIZE && d[len - 1] == 0) + len--; + + return len; +} + +static inline void sclp_trace_bin(int prio, void *d, int len, int errlen) +{ + debug_event(&sclp_debug, prio, d, no_zeroes_len(d, len)); + if (errlen) + debug_event(&sclp_debug_err, 0, d, no_zeroes_len(d, errlen)); +} + +static inline int abbrev_len(sclp_cmdw_t cmd, struct sccb_header *sccb) +{ + struct evbuf_header *evbuf = (struct evbuf_header *)(sccb + 1); + int len = sccb->length, limit = SCLP_TRACE_MAX_SIZE; + + /* Full SCCB tracing if debug level is set to max. */ + if (sclp_debug.level == DEBUG_MAX_LEVEL) + return len; + + /* Minimal tracing for console writes. */ + if (cmd == SCLP_CMDW_WRITE_EVENT_DATA && + (evbuf->type == EVTYP_MSG || evbuf->type == EVTYP_VT220MSG)) + limit = SCLP_TRACE_ENTRY_SIZE; + + return min(len, limit); +} + +static inline void sclp_trace_sccb(int prio, char *id, u32 a, u64 b, + sclp_cmdw_t cmd, struct sccb_header *sccb, + bool err) +{ + sclp_trace(prio, id, a, b, err); + if (sccb) { + sclp_trace_bin(prio + 1, sccb, abbrev_len(cmd, sccb), + err ? sccb->length : 0); + } +} + +static inline void sclp_trace_evbuf(int prio, char *id, u32 a, u64 b, + struct evbuf_header *evbuf, bool err) +{ + sclp_trace(prio, id, a, b, err); + sclp_trace_bin(prio + 1, evbuf, + min((int)evbuf->length, (int)SCLP_TRACE_EVENT_MAX_SIZE), + err ? evbuf->length : 0); +} + +static inline void sclp_trace_req(int prio, char *id, struct sclp_req *req, + bool err) +{ + struct sccb_header *sccb = req->sccb; + union { + struct { + u16 status; + u16 response; + u16 timeout; + u16 start_count; + }; + u64 b; + } summary; + + summary.status = req->status; + summary.response = sccb ? sccb->response_code : 0; + summary.timeout = (u16)req->queue_timeout; + summary.start_count = (u16)req->start_count; + + sclp_trace(prio, id, __pa(sccb), summary.b, err); +} + +static inline void sclp_trace_register(int prio, char *id, u32 a, u64 b, + struct sclp_register *reg) +{ + struct { + u64 receive; + u64 send; + } d; + + d.receive = reg->receive_mask; + d.send = reg->send_mask; + + sclp_trace(prio, id, a, b, false); + sclp_trace_bin(prio, &d, sizeof(d), 0); +} + +static int __init sclp_setup_console_pages(char *str) +{ + int pages, rc; + + rc = kstrtoint(str, 0, &pages); + if (!rc && pages >= SCLP_CONSOLE_PAGES) + sclp_console_pages = pages; + return 1; +} + +__setup("sclp_con_pages=", sclp_setup_console_pages); + +static int __init sclp_setup_console_drop(char *str) +{ + return kstrtobool(str, &sclp_console_drop) == 0; +} + +__setup("sclp_con_drop=", sclp_setup_console_drop); + +/* Timer for request retries. */ +static struct timer_list sclp_request_timer; + +/* Timer for queued requests. */ +static struct timer_list sclp_queue_timer; + +/* 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_reset_pending +} 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 30 + +static void sclp_request_timeout(bool force_restart); +static void sclp_process_queue(void); +static void __sclp_make_read_req(void); +static int sclp_init_mask(int calculate); +static int sclp_init(void); + +static void +__sclp_queue_read_req(void) +{ + if (sclp_reading_state == sclp_reading_state_idle) { + 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); + } +} + +/* Set up request retry timer. Called while sclp_lock is locked. */ +static inline void +__sclp_set_request_timer(unsigned long time, void (*cb)(struct timer_list *)) +{ + del_timer(&sclp_request_timer); + sclp_request_timer.function = cb; + sclp_request_timer.expires = jiffies + time; + add_timer(&sclp_request_timer); +} + +static void sclp_request_timeout_restart(struct timer_list *unused) +{ + sclp_request_timeout(true); +} + +static void sclp_request_timeout_normal(struct timer_list *unused) +{ + sclp_request_timeout(false); +} + +/* Request timeout handler. Restart the request queue. If force_restart, + * force restart of running request. */ +static void sclp_request_timeout(bool force_restart) +{ + unsigned long flags; + + /* TMO: A timeout occurred (a=force_restart) */ + sclp_trace(2, "TMO", force_restart, 0, true); + + spin_lock_irqsave(&sclp_lock, flags); + if (force_restart) { + if (sclp_running_state == sclp_running_state_running) { + /* Break running state and queue NOP read event request + * to get a defined interface state. */ + __sclp_queue_read_req(); + sclp_running_state = sclp_running_state_idle; + } + } else { + __sclp_set_request_timer(SCLP_BUSY_INTERVAL * HZ, + sclp_request_timeout_normal); + } + spin_unlock_irqrestore(&sclp_lock, flags); + sclp_process_queue(); +} + +/* + * Returns the expire value in jiffies of the next pending request timeout, + * if any. Needs to be called with sclp_lock. + */ +static unsigned long __sclp_req_queue_find_next_timeout(void) +{ + unsigned long expires_next = 0; + struct sclp_req *req; + + list_for_each_entry(req, &sclp_req_queue, list) { + if (!req->queue_expires) + continue; + if (!expires_next || + (time_before(req->queue_expires, expires_next))) + expires_next = req->queue_expires; + } + return expires_next; +} + +/* + * Returns expired request, if any, and removes it from the list. + */ +static struct sclp_req *__sclp_req_queue_remove_expired_req(void) +{ + unsigned long flags, now; + struct sclp_req *req; + + spin_lock_irqsave(&sclp_lock, flags); + now = jiffies; + /* Don't need list_for_each_safe because we break out after list_del */ + list_for_each_entry(req, &sclp_req_queue, list) { + if (!req->queue_expires) + continue; + if (time_before_eq(req->queue_expires, now)) { + if (req->status == SCLP_REQ_QUEUED) { + req->status = SCLP_REQ_QUEUED_TIMEOUT; + list_del(&req->list); + goto out; + } + } + } + req = NULL; +out: + spin_unlock_irqrestore(&sclp_lock, flags); + return req; +} + +/* + * Timeout handler for queued requests. Removes request from list and + * invokes callback. This timer can be set per request in situations where + * waiting too long would be harmful to the system, e.g. during SE reboot. + */ +static void sclp_req_queue_timeout(struct timer_list *unused) +{ + unsigned long flags, expires_next; + struct sclp_req *req; + + do { + req = __sclp_req_queue_remove_expired_req(); + + if (req) { + /* RQTM: Request timed out (a=sccb, b=summary) */ + sclp_trace_req(2, "RQTM", req, true); + } + + if (req && req->callback) + req->callback(req, req->callback_data); + } while (req); + + spin_lock_irqsave(&sclp_lock, flags); + expires_next = __sclp_req_queue_find_next_timeout(); + if (expires_next) + mod_timer(&sclp_queue_timer, expires_next); + spin_unlock_irqrestore(&sclp_lock, flags); +} + +static int sclp_service_call_trace(sclp_cmdw_t command, void *sccb) +{ + static u64 srvc_count; + int rc; + + /* SRV1: Service call about to be issued (a=command, b=sccb address) */ + sclp_trace_sccb(0, "SRV1", command, (u64)sccb, command, sccb, false); + + rc = sclp_service_call(command, sccb); + + /* SRV2: Service call was issued (a=rc, b=SRVC sequence number) */ + sclp_trace(0, "SRV2", -rc, ++srvc_count, rc != 0); + + if (rc == 0) + active_cmd = command; + + return rc; +} + +/* 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 = sclp_service_call_trace(req->command, req->sccb); + req->start_count++; + + if (rc == 0) { + /* Successfully 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_restart); + return 0; + } else if (rc == -EBUSY) { + /* Try again later */ + __sclp_set_request_timer(SCLP_BUSY_INTERVAL * HZ, + sclp_request_timeout_normal); + 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 */ + if (req->start_count > 1) { + /* Cannot abort already submitted request - could still + * be active at the SCLP */ + __sclp_set_request_timer(SCLP_BUSY_INTERVAL * HZ, + sclp_request_timeout_normal); + break; + } + /* Post-processing for aborted request */ + list_del(&req->list); + + /* RQAB: Request aborted (a=sccb, b=summary) */ + sclp_trace_req(2, "RQAB", req, true); + + 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); +} + +static int __sclp_can_add_request(struct sclp_req *req) +{ + if (req == &sclp_init_req) + return 1; + if (sclp_init_state != sclp_init_state_initialized) + return 0; + if (sclp_activation_state != sclp_activation_state_active) + return 0; + return 1; +} + +/* 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_can_add_request(req)) { + spin_unlock_irqrestore(&sclp_lock, flags); + return -EIO; + } + + /* RQAD: Request was added (a=sccb, b=caller) */ + sclp_trace(2, "RQAD", __pa(req->sccb), _RET_IP_, false); + + req->status = SCLP_REQ_QUEUED; + req->start_count = 0; + list_add_tail(&req->list, &sclp_req_queue); + rc = 0; + if (req->queue_timeout) { + req->queue_expires = jiffies + req->queue_timeout * HZ; + if (!timer_pending(&sclp_queue_timer) || + time_after(sclp_queue_timer.expires, req->queue_expires)) + mod_timer(&sclp_queue_timer, req->queue_expires); + } else + req->queue_expires = 0; + /* Start if request is first in list */ + if (sclp_running_state == sclp_running_state_idle && + 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) { + evbuf = (struct evbuf_header *) ((addr_t) sccb + offset); + /* Check for malformed hardware response */ + if (evbuf->length == 0) + break; + /* Search for event handler */ + reg = NULL; + list_for_each(l, &sclp_reg_list) { + reg = list_entry(l, struct sclp_register, list); + if (reg->receive_mask & SCLP_EVTYP_MASK(evbuf->type)) + break; + else + reg = NULL; + } + + /* EVNT: Event callback (b=receiver) */ + sclp_trace_evbuf(2, "EVNT", 0, reg ? (u64)reg->receiver_fn : 0, + evbuf, !reg); + + 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 = -EOPNOTSUPP; + } + 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 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_READ_EVENT_DATA; + 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 == __pa(req->sccb)) + return req; + } + return NULL; +} + +static bool ok_response(u32 sccb_int, sclp_cmdw_t cmd) +{ + struct sccb_header *sccb = (struct sccb_header *)__va(sccb_int); + struct evbuf_header *evbuf; + u16 response; + + if (!sccb) + return true; + + /* Check SCCB response. */ + response = sccb->response_code & 0xff; + if (response != 0x10 && response != 0x20) + return false; + + /* Check event-processed flag on outgoing events. */ + if (cmd == SCLP_CMDW_WRITE_EVENT_DATA) { + evbuf = (struct evbuf_header *)(sccb + 1); + if (!(evbuf->flags & 0x80)) + return false; + } + + return true; +} + +/* 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 ext_code ext_code, + unsigned int param32, unsigned long param64) +{ + struct sclp_req *req; + u32 finished_sccb; + u32 evbuf_pending; + + inc_irq_stat(IRQEXT_SCP); + spin_lock(&sclp_lock); + finished_sccb = param32 & 0xfffffff8; + evbuf_pending = param32 & 0x3; + + /* INT: Interrupt received (a=intparm, b=cmd) */ + sclp_trace_sccb(0, "INT", param32, active_cmd, active_cmd, + (struct sccb_header *)__va(finished_sccb), + !ok_response(finished_sccb, active_cmd)); + + if (finished_sccb) { + del_timer(&sclp_request_timer); + sclp_running_state = sclp_running_state_reset_pending; + req = __sclp_find_req(finished_sccb); + if (req) { + /* Request post-processing */ + list_del(&req->list); + req->status = SCLP_REQ_DONE; + + /* RQOK: Request success (a=sccb, b=summary) */ + sclp_trace_req(2, "RQOK", req, false); + + if (req->callback) { + spin_unlock(&sclp_lock); + req->callback(req, req->callback_data); + spin_lock(&sclp_lock); + } + } else { + /* UNEX: Unexpected SCCB completion (a=sccb address) */ + sclp_trace(0, "UNEX", finished_sccb, 0, true); + } + sclp_running_state = sclp_running_state_idle; + active_cmd = 0; + } + if (evbuf_pending && + sclp_activation_state == sclp_activation_state_active) + __sclp_queue_read_req(); + spin_unlock(&sclp_lock); + sclp_process_queue(); +} + +/* 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 long old_tick; + unsigned long flags; + unsigned long cr0, cr0_sync; + static u64 sync_count; + u64 timeout; + int irq_context; + + /* SYN1: Synchronous wait start (a=runstate, b=sync count) */ + sclp_trace(4, "SYN1", sclp_running_state, ++sync_count, false); + + /* 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 = get_tod_clock_fast() + + sclp_tod_from_jiffies(sclp_request_timer.expires - + jiffies); + } + local_irq_save(flags); + /* Prevent bottom half from executing once we force interrupts open */ + irq_context = in_interrupt(); + if (!irq_context) + local_bh_disable(); + /* Enable service-signal interruption, disable timer interrupts */ + old_tick = local_tick_disable(); + trace_hardirqs_on(); + __ctl_store(cr0, 0, 0); + cr0_sync = cr0 & ~CR0_IRQ_SUBCLASS_MASK; + cr0_sync |= 1UL << (63 - 54); + __ctl_load(cr0_sync, 0, 0); + __arch_local_irq_stosm(0x01); + /* Loop until driver state indicates finished request */ + while (sclp_running_state != sclp_running_state_idle) { + /* Check for expired request timer */ + if (get_tod_clock_fast() > timeout && del_timer(&sclp_request_timer)) + sclp_request_timer.function(&sclp_request_timer); + cpu_relax(); + } + local_irq_disable(); + __ctl_load(cr0, 0, 0); + if (!irq_context) + _local_bh_enable(); + local_tick_enable(old_tick); + local_irq_restore(flags); + + /* SYN2: Synchronous wait end (a=runstate, b=sync_count) */ + sclp_trace(4, "SYN2", sclp_running_state, sync_count, false); +} +EXPORT_SYMBOL(sclp_sync_wait); + +/* Dispatch changes in send and receive mask to registered listeners. */ +static 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->send_mask & sclp_receive_mask; + send_mask = reg->receive_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) { + /* STCG: State-change callback (b=callback) */ + sclp_trace(2, "STCG", 0, (u64)reg->state_change_fn, + false); + + 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; + u8 masks[2 * 1021 + 4]; /* variable length */ + /* + * u8 sclp_receive_mask[mask_length]; + * u8 sclp_send_mask[mask_length]; + * 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; + + BUILD_BUG_ON(sizeof(struct sclp_statechangebuf) > PAGE_SIZE); + + scbuf = (struct sclp_statechangebuf *) evbuf; + spin_lock_irqsave(&sclp_lock, flags); + if (scbuf->validity_sclp_receive_mask) + sclp_receive_mask = sccb_get_recv_mask(scbuf); + if (scbuf->validity_sclp_send_mask) + sclp_send_mask = sccb_get_send_mask(scbuf); + spin_unlock_irqrestore(&sclp_lock, flags); + if (scbuf->validity_sclp_active_facility_mask) + sclp.facilities = scbuf->sclp_active_facility_mask; + 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; + + /* REG: Event listener registered (b=caller) */ + sclp_trace_register(2, "REG", 0, _RET_IP_, reg); + + 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(®->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(®->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; + + /* UREG: Event listener unregistered (b=caller) */ + sclp_trace_register(2, "UREG", 0, _RET_IP_, reg); + + spin_lock_irqsave(&sclp_lock, flags); + list_del(®->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); + +/* Prepare init mask request. Called while sclp_lock is locked. */ +static inline void +__sclp_make_init_req(sccb_mask_t receive_mask, sccb_mask_t send_mask) +{ + struct init_sccb *sccb = sclp_init_sccb; + + clear_page(sccb); + memset(&sclp_init_req, 0, sizeof(struct sclp_req)); + sclp_init_req.command = SCLP_CMDW_WRITE_EVENT_MASK; + 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(*sccb); + if (sclp_mask_compat_mode) + sccb->mask_length = SCLP_MASK_SIZE_COMPAT; + else + sccb->mask_length = sizeof(sccb_mask_t); + sccb_set_recv_mask(sccb, receive_mask); + sccb_set_send_mask(sccb, send_mask); + sccb_set_sclp_recv_mask(sccb, 0); + sccb_set_sclp_send_mask(sccb, 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 = 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_get_sclp_recv_mask(sccb); + sclp_send_mask = sccb_get_sclp_send_mask(sccb); + } 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 ext_code ext_code, + unsigned int param32, unsigned long param64) +{ + u32 finished_sccb; + + inc_irq_stat(IRQEXT_SCP); + finished_sccb = param32 & 0xfffffff8; + /* Is this the interrupt we are waiting for? */ + if (finished_sccb == 0) + return; + if (finished_sccb != __pa(sclp_init_sccb)) + panic("sclp: unsolicited interrupt for buffer at 0x%x\n", + finished_sccb); + 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(struct timer_list *unused) +{ + 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_external_irq(EXT_IRQ_SERVICE_SIG, sclp_check_handler); + 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 = sclp_service_call_trace(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); + spin_unlock_irqrestore(&sclp_lock, flags); + /* Enable service-signal interruption - needs to happen + * with IRQs enabled. */ + irq_subclass_register(IRQ_SUBCLASS_SERVICE_SIGNAL); + /* Wait for signal from interrupt or timeout */ + sclp_sync_wait(); + /* Disable service-signal interruption - needs to happen + * with IRQs enabled. */ + irq_subclass_unregister(IRQ_SUBCLASS_SERVICE_SIGNAL); + spin_lock_irqsave(&sclp_lock, flags); + del_timer(&sclp_request_timer); + rc = -EBUSY; + if (sclp_init_req.status == SCLP_REQ_DONE) { + if (sccb->header.response_code == 0x20) { + rc = 0; + break; + } else if (sccb->header.response_code == 0x74f0) { + if (!sclp_mask_compat_mode) { + sclp_mask_compat_mode = true; + retry = 0; + } + } + } + } + unregister_external_irq(EXT_IRQ_SERVICE_SIG, sclp_check_handler); + 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 +}; + +static ssize_t con_pages_show(struct device_driver *dev, char *buf) +{ + return sysfs_emit(buf, "%i\n", sclp_console_pages); +} + +static DRIVER_ATTR_RO(con_pages); + +static ssize_t con_drop_store(struct device_driver *dev, const char *buf, size_t count) +{ + int rc; + + rc = kstrtobool(buf, &sclp_console_drop); + return rc ?: count; +} + +static ssize_t con_drop_show(struct device_driver *dev, char *buf) +{ + return sysfs_emit(buf, "%i\n", sclp_console_drop); +} + +static DRIVER_ATTR_RW(con_drop); + +static ssize_t con_full_show(struct device_driver *dev, char *buf) +{ + return sysfs_emit(buf, "%lu\n", sclp_console_full); +} + +static DRIVER_ATTR_RO(con_full); + +static struct attribute *sclp_drv_attrs[] = { + &driver_attr_con_pages.attr, + &driver_attr_con_drop.attr, + &driver_attr_con_full.attr, + NULL, +}; +static struct attribute_group sclp_drv_attr_group = { + .attrs = sclp_drv_attrs, +}; +static const struct attribute_group *sclp_drv_attr_groups[] = { + &sclp_drv_attr_group, + NULL, +}; + +static struct platform_driver sclp_pdrv = { + .driver = { + .name = "sclp", + .groups = sclp_drv_attr_groups, + }, +}; + +/* Initialize SCLP driver. Return zero if driver is operational, non-zero + * otherwise. */ +static int +sclp_init(void) +{ + unsigned long flags; + int rc = 0; + + spin_lock_irqsave(&sclp_lock, flags); + /* Check for previous or running initialization */ + if (sclp_init_state != sclp_init_state_uninitialized) + goto fail_unlock; + sclp_init_state = sclp_init_state_initializing; + sclp_read_sccb = (void *) __get_free_page(GFP_ATOMIC | GFP_DMA); + sclp_init_sccb = (void *) __get_free_page(GFP_ATOMIC | GFP_DMA); + BUG_ON(!sclp_read_sccb || !sclp_init_sccb); + /* Set up variables */ + list_add(&sclp_state_change_event.list, &sclp_reg_list); + timer_setup(&sclp_request_timer, NULL, 0); + timer_setup(&sclp_queue_timer, sclp_req_queue_timeout, 0); + /* Check interface */ + spin_unlock_irqrestore(&sclp_lock, flags); + rc = sclp_check_interface(); + spin_lock_irqsave(&sclp_lock, flags); + if (rc) + goto fail_init_state_uninitialized; + /* Register reboot handler */ + rc = register_reboot_notifier(&sclp_reboot_notifier); + if (rc) + goto fail_init_state_uninitialized; + /* Register interrupt handler */ + rc = register_external_irq(EXT_IRQ_SERVICE_SIG, sclp_interrupt_handler); + if (rc) + goto fail_unregister_reboot_notifier; + sclp_init_state = sclp_init_state_initialized; + spin_unlock_irqrestore(&sclp_lock, flags); + /* Enable service-signal external interruption - needs to happen with + * IRQs enabled. */ + irq_subclass_register(IRQ_SUBCLASS_SERVICE_SIGNAL); + sclp_init_mask(1); + return 0; + +fail_unregister_reboot_notifier: + unregister_reboot_notifier(&sclp_reboot_notifier); +fail_init_state_uninitialized: + sclp_init_state = sclp_init_state_uninitialized; + free_page((unsigned long) sclp_read_sccb); + free_page((unsigned long) sclp_init_sccb); +fail_unlock: + spin_unlock_irqrestore(&sclp_lock, flags); + return rc; +} + +static __init int sclp_initcall(void) +{ + int rc; + + rc = platform_driver_register(&sclp_pdrv); + if (rc) + return rc; + + return sclp_init(); +} + +arch_initcall(sclp_initcall); |