linux/drivers/s390/crypto/ap_bus.h
Harald Freudenberger 01396a374c s390/zcrypt: revisit ap device remove procedure
Working with the vfio-ap driver let to some revisit of the way
how an ap (queue) device is removed from the driver.
With the current implementation all the cleanup was done before
the driver even got notified about the removal. Now the ap
queue removal is done in 3 steps:
1) A preparation step, all ap messages within the queue
   are flushed and so the driver does 'receive' them.
   Also a new state AP_STATE_REMOVE assigned to the queue
   makes sure there are no new messages queued in.
2) Now the driver's remove function is invoked and the
   driver should do the job of cleaning up it's internal
   administration lists or whatever. After 2) is done
   it is guaranteed, that the driver is not invoked any
   more. On the other hand the driver has to make sure
   that the APQN is not accessed any more after step 2
   is complete.
3) Now the ap bus code does the job of total cleanup of the
   APQN. A reset with zero is triggered and the state of
   the queue goes to AP_STATE_UNBOUND.
   After step 3) is complete, the ap queue has no pending
   messages and the APQN is cleared and so there are no
   requests and replies lingering around in the firmware
   queue for this APQN. Also the interrupts are disabled.

After these remove steps the ap queue device may be assigned
to another driver.

Stress testing this remove/probe procedure showed a problem with the
correct module reference counting. The actual receive of an reply in
the driver is done asynchronous with completions. So with a driver
change on an ap queue the message flush triggers completions but the
threads waiting for the completions may run at a time where the queue
already has the new driver assigned. So the module_put() at receive
time needs to be done on the driver module which queued the ap
message. This change is also part of this patch.

Signed-off-by: Harald Freudenberger <freude@linux.ibm.com>
Reviewed-by: Ingo Franzki <ifranzki@linux.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2019-03-06 09:34:03 +01:00

313 lines
9.8 KiB
C

/* SPDX-License-Identifier: GPL-2.0+ */
/*
* Copyright IBM Corp. 2006, 2012
* Author(s): Cornelia Huck <cornelia.huck@de.ibm.com>
* Martin Schwidefsky <schwidefsky@de.ibm.com>
* Ralph Wuerthner <rwuerthn@de.ibm.com>
* Felix Beck <felix.beck@de.ibm.com>
* Holger Dengler <hd@linux.vnet.ibm.com>
*
* Adjunct processor bus header file.
*/
#ifndef _AP_BUS_H_
#define _AP_BUS_H_
#include <linux/device.h>
#include <linux/types.h>
#include <asm/isc.h>
#include <asm/ap.h>
#define AP_DEVICES 256 /* Number of AP devices. */
#define AP_DOMAINS 256 /* Number of AP domains. */
#define AP_IOCTLS 256 /* Number of ioctls. */
#define AP_RESET_TIMEOUT (HZ*0.7) /* Time in ticks for reset timeouts. */
#define AP_CONFIG_TIME 30 /* Time in seconds between AP bus rescans. */
#define AP_POLL_TIME 1 /* Time in ticks between receive polls. */
extern int ap_domain_index;
extern spinlock_t ap_list_lock;
extern struct list_head ap_card_list;
static inline int ap_test_bit(unsigned int *ptr, unsigned int nr)
{
return (*ptr & (0x80000000u >> nr)) != 0;
}
#define AP_RESPONSE_NORMAL 0x00
#define AP_RESPONSE_Q_NOT_AVAIL 0x01
#define AP_RESPONSE_RESET_IN_PROGRESS 0x02
#define AP_RESPONSE_DECONFIGURED 0x03
#define AP_RESPONSE_CHECKSTOPPED 0x04
#define AP_RESPONSE_BUSY 0x05
#define AP_RESPONSE_INVALID_ADDRESS 0x06
#define AP_RESPONSE_OTHERWISE_CHANGED 0x07
#define AP_RESPONSE_Q_FULL 0x10
#define AP_RESPONSE_NO_PENDING_REPLY 0x10
#define AP_RESPONSE_INDEX_TOO_BIG 0x11
#define AP_RESPONSE_NO_FIRST_PART 0x13
#define AP_RESPONSE_MESSAGE_TOO_BIG 0x15
#define AP_RESPONSE_REQ_FAC_NOT_INST 0x16
/*
* Known device types
*/
#define AP_DEVICE_TYPE_PCICC 3
#define AP_DEVICE_TYPE_PCICA 4
#define AP_DEVICE_TYPE_PCIXCC 5
#define AP_DEVICE_TYPE_CEX2A 6
#define AP_DEVICE_TYPE_CEX2C 7
#define AP_DEVICE_TYPE_CEX3A 8
#define AP_DEVICE_TYPE_CEX3C 9
#define AP_DEVICE_TYPE_CEX4 10
#define AP_DEVICE_TYPE_CEX5 11
#define AP_DEVICE_TYPE_CEX6 12
/*
* Known function facilities
*/
#define AP_FUNC_MEX4K 1
#define AP_FUNC_CRT4K 2
#define AP_FUNC_COPRO 3
#define AP_FUNC_ACCEL 4
#define AP_FUNC_EP11 5
#define AP_FUNC_APXA 6
/*
* AP interrupt states
*/
#define AP_INTR_DISABLED 0 /* AP interrupt disabled */
#define AP_INTR_ENABLED 1 /* AP interrupt enabled */
/*
* AP device states
*/
enum ap_state {
AP_STATE_RESET_START,
AP_STATE_RESET_WAIT,
AP_STATE_SETIRQ_WAIT,
AP_STATE_IDLE,
AP_STATE_WORKING,
AP_STATE_QUEUE_FULL,
AP_STATE_SUSPEND_WAIT,
AP_STATE_REMOVE, /* about to be removed from driver */
AP_STATE_UNBOUND, /* momentary not bound to a driver */
AP_STATE_BORKED, /* broken */
NR_AP_STATES
};
/*
* AP device events
*/
enum ap_event {
AP_EVENT_POLL,
AP_EVENT_TIMEOUT,
NR_AP_EVENTS
};
/*
* AP wait behaviour
*/
enum ap_wait {
AP_WAIT_AGAIN, /* retry immediately */
AP_WAIT_TIMEOUT, /* wait for timeout */
AP_WAIT_INTERRUPT, /* wait for thin interrupt (if available) */
AP_WAIT_NONE, /* no wait */
NR_AP_WAIT
};
struct ap_device;
struct ap_message;
/*
* The ap driver struct includes a flags field which holds some info for
* the ap bus about the driver. Currently only one flag is supported and
* used: The DEFAULT flag marks an ap driver as a default driver which is
* used together with the apmask and aqmask whitelisting of the ap bus.
*/
#define AP_DRIVER_FLAG_DEFAULT 0x0001
struct ap_driver {
struct device_driver driver;
struct ap_device_id *ids;
unsigned int flags;
int (*probe)(struct ap_device *);
void (*remove)(struct ap_device *);
void (*suspend)(struct ap_device *);
void (*resume)(struct ap_device *);
};
#define to_ap_drv(x) container_of((x), struct ap_driver, driver)
int ap_driver_register(struct ap_driver *, struct module *, char *);
void ap_driver_unregister(struct ap_driver *);
struct ap_device {
struct device device;
struct ap_driver *drv; /* Pointer to AP device driver. */
int device_type; /* AP device type. */
};
#define to_ap_dev(x) container_of((x), struct ap_device, device)
struct ap_card {
struct ap_device ap_dev;
struct list_head list; /* Private list of AP cards. */
struct list_head queues; /* List of assoc. AP queues */
void *private; /* ap driver private pointer. */
int raw_hwtype; /* AP raw hardware type. */
unsigned int functions; /* AP device function bitfield. */
int queue_depth; /* AP queue depth.*/
int id; /* AP card number. */
atomic_t total_request_count; /* # requests ever for this AP device.*/
};
#define to_ap_card(x) container_of((x), struct ap_card, ap_dev.device)
struct ap_queue {
struct ap_device ap_dev;
struct list_head list; /* Private list of AP queues. */
struct ap_card *card; /* Ptr to assoc. AP card. */
spinlock_t lock; /* Per device lock. */
void *private; /* ap driver private pointer. */
ap_qid_t qid; /* AP queue id. */
int interrupt; /* indicate if interrupts are enabled */
int queue_count; /* # messages currently on AP queue. */
enum ap_state state; /* State of the AP device. */
int pendingq_count; /* # requests on pendingq list. */
int requestq_count; /* # requests on requestq list. */
int total_request_count; /* # requests ever for this AP device.*/
int request_timeout; /* Request timeout in jiffies. */
struct timer_list timeout; /* Timer for request timeouts. */
struct list_head pendingq; /* List of message sent to AP queue. */
struct list_head requestq; /* List of message yet to be sent. */
struct ap_message *reply; /* Per device reply message. */
};
#define to_ap_queue(x) container_of((x), struct ap_queue, ap_dev.device)
typedef enum ap_wait (ap_func_t)(struct ap_queue *queue);
struct ap_message {
struct list_head list; /* Request queueing. */
unsigned long long psmid; /* Message id. */
void *message; /* Pointer to message buffer. */
size_t length; /* Message length. */
int rc; /* Return code for this message */
void *private; /* ap driver private pointer. */
unsigned int special:1; /* Used for special commands. */
/* receive is called from tasklet context */
void (*receive)(struct ap_queue *, struct ap_message *,
struct ap_message *);
};
/**
* ap_init_message() - Initialize ap_message.
* Initialize a message before using. Otherwise this might result in
* unexpected behaviour.
*/
static inline void ap_init_message(struct ap_message *ap_msg)
{
memset(ap_msg, 0, sizeof(*ap_msg));
}
/**
* ap_release_message() - Release ap_message.
* Releases all memory used internal within the ap_message struct
* Currently this is the message and private field.
*/
static inline void ap_release_message(struct ap_message *ap_msg)
{
kzfree(ap_msg->message);
kzfree(ap_msg->private);
}
#define for_each_ap_card(_ac) \
list_for_each_entry(_ac, &ap_card_list, list)
#define for_each_ap_queue(_aq, _ac) \
list_for_each_entry(_aq, &(_ac)->queues, list)
/*
* Note: don't use ap_send/ap_recv after using ap_queue_message
* for the first time. Otherwise the ap message queue will get
* confused.
*/
int ap_send(ap_qid_t, unsigned long long, void *, size_t);
int ap_recv(ap_qid_t, unsigned long long *, void *, size_t);
enum ap_wait ap_sm_event(struct ap_queue *aq, enum ap_event event);
enum ap_wait ap_sm_event_loop(struct ap_queue *aq, enum ap_event event);
void ap_queue_message(struct ap_queue *aq, struct ap_message *ap_msg);
void ap_cancel_message(struct ap_queue *aq, struct ap_message *ap_msg);
void ap_flush_queue(struct ap_queue *aq);
void *ap_airq_ptr(void);
void ap_wait(enum ap_wait wait);
void ap_request_timeout(struct timer_list *t);
void ap_bus_force_rescan(void);
void ap_queue_init_reply(struct ap_queue *aq, struct ap_message *ap_msg);
struct ap_queue *ap_queue_create(ap_qid_t qid, int device_type);
void ap_queue_prepare_remove(struct ap_queue *aq);
void ap_queue_remove(struct ap_queue *aq);
void ap_queue_suspend(struct ap_device *ap_dev);
void ap_queue_resume(struct ap_device *ap_dev);
void ap_queue_reinit_state(struct ap_queue *aq);
struct ap_card *ap_card_create(int id, int queue_depth, int raw_device_type,
int comp_device_type, unsigned int functions);
struct ap_perms {
unsigned long ioctlm[BITS_TO_LONGS(AP_IOCTLS)];
unsigned long apm[BITS_TO_LONGS(AP_DEVICES)];
unsigned long aqm[BITS_TO_LONGS(AP_DOMAINS)];
};
extern struct ap_perms ap_perms;
extern struct mutex ap_perms_mutex;
/*
* check APQN for owned/reserved by ap bus and default driver(s).
* Checks if this APQN is or will be in use by the ap bus
* and the default set of drivers.
* If yes, returns 1, if not returns 0. On error a negative
* errno value is returned.
*/
int ap_owned_by_def_drv(int card, int queue);
/*
* check 'matrix' of APQNs for owned/reserved by ap bus and
* default driver(s).
* Checks if there is at least one APQN in the given 'matrix'
* marked as owned/reserved by the ap bus and default driver(s).
* If such an APQN is found the return value is 1, otherwise
* 0 is returned. On error a negative errno value is returned.
* The parameter apm is a bitmask which should be declared
* as DECLARE_BITMAP(apm, AP_DEVICES), the aqm parameter is
* similar, should be declared as DECLARE_BITMAP(aqm, AP_DOMAINS).
*/
int ap_apqn_in_matrix_owned_by_def_drv(unsigned long *apm,
unsigned long *aqm);
/*
* ap_parse_mask_str() - helper function to parse a bitmap string
* and clear/set the bits in the bitmap accordingly. The string may be
* given as absolute value, a hex string like 0x1F2E3D4C5B6A" simple
* overwriting the current content of the bitmap. Or as relative string
* like "+1-16,-32,-0x40,+128" where only single bits or ranges of
* bits are cleared or set. Distinction is done based on the very
* first character which may be '+' or '-' for the relative string
* and othewise assume to be an absolute value string. If parsing fails
* a negative errno value is returned. All arguments and bitmaps are
* big endian order.
*/
int ap_parse_mask_str(const char *str,
unsigned long *bitmap, int bits,
struct mutex *lock);
#endif /* _AP_BUS_H_ */