sys/sys/msgport.h

   1 /*
   2  * SYS/MSGPORT.H
   3  *
   4  *      Implements LWKT messages and ports.
   5  */
   6
   7 #ifndef _SYS_MSGPORT_H_
   8 #define _SYS_MSGPORT_H_
   9
  10 #ifndef _SYS_QUEUE_H_
  11 #include <sys/queue.h>          /* TAILQ_* macros */
  12 #endif
  13 #ifndef _SYS_STDINT_H_
  14 #include <sys/stdint.h>
  15 #endif
  16 #ifndef _SYS_SPINLOCK_H_
  17 #include <sys/spinlock.h>
  18 #endif
  19
  20 #ifdef _KERNEL
  21
  22 #ifndef _SYS_MALLOC_H_
  23 #include <sys/malloc.h>
  24 #endif
  25
  26 #endif
  27
  28 struct lwkt_msg;
  29 struct lwkt_port;
  30 struct lwkt_serialize;
  31 struct thread;
  32
  33 typedef struct lwkt_msg         *lwkt_msg_t;
  34 typedef struct lwkt_port        *lwkt_port_t;
  35
  36 typedef TAILQ_HEAD(lwkt_msg_queue, lwkt_msg) lwkt_msg_queue;
  37
  38 /*
  39  * The standard message and port structure for communications between
  40  * threads.  See kern/lwkt_msgport.c for documentation on how messages and
  41  * ports work.
  42  *
  43  * A message may only be manipulated by whomever currently owns it,
  44  * which generally means the originating port if the message has
  45  * not been sent yet or has been replied, and the target port if the message
  46  * has been sent and/or is undergoing processing.
  47  *
  48  * NOTE! 64-bit-align this structure.
  49  */
  50 typedef struct lwkt_msg {
  51     TAILQ_ENTRY(lwkt_msg) ms_node;      /* link node */
  52     lwkt_port_t ms_target_port;         /* current target or relay port */
  53     lwkt_port_t ms_reply_port;          /* async replies returned here */
  54     void        (*ms_abortfn)(struct lwkt_msg *);
  55     int         ms_flags;               /* message flags */
  56     int         ms_error;               /* positive error code or 0 */
  57     union {
  58         void    *ms_resultp;            /* misc pointer data or result */
  59         int     ms_result;              /* standard 'int'eger result */
  60         long    ms_lresult;             /* long result */
  61         int     ms_fds[2];              /* two int bit results */
  62         __int32_t ms_result32;          /* 32 bit result */
  63         __int64_t ms_result64;          /* 64 bit result */
  64         __off_t ms_offset;              /* off_t result */
  65     } u;
  66     void        (*ms_receiptfn)(struct lwkt_msg *, lwkt_port_t);
  67 } lwkt_msg;
  68
  69 /*
  70  * Message state flags are manipulated by the current owner only.
  71  *
  72  * DONE         Indicates completion of the reply.  This flag is also set
  73  *              for unsent messages.
  74  *
  75  * REPLY        Indicates message is being replied but may or may not
  76  *              have been queued or returned yet.  This bit is left set
  77  *              when a message is retrieved from a reply port so the caller
  78  *              can distinguish between requests and replies.
  79  *
  80  * QUEUED       Indicates message is queued on reply or target port, or
  81  *              some other port.
  82  *
  83  * SYNC         Indicates that the originator is blocked directly on the
  84  *              message and that the message should be signaled on
  85  *              completion instead of queued.
  86  *
  87  * INTRANSIT    Indicates that the message state is indeterminant (e.g.
  88  *              being passed through an IPI).
  89  *
  90  * ABORTABLE    Static flag indicates that ms_abortfn is valid.
  91  *
  92  * High 16 bits are available to message handlers.
  93  */
  94 #define MSGF_DONE       0x0001          /* message is complete */
  95 #define MSGF_REPLY      0x0002          /* asynch message has been returned */
  96 #define MSGF_QUEUED     0x0004          /* message has been queued sanitychk */
  97 #define MSGF_SYNC       0x0008          /* synchronous message operation */
  98 #define MSGF_INTRANSIT  0x0010          /* in-transit (IPI) */
  99 #define MSGF_WAITING    0x0020          /* MSGF_SYNC being waited upon */
 100 #define MSGF_DROPABLE   0x0040          /* message supports drop */
 101 #define MSGF_ABORTABLE  0x0080          /* message supports abort */
 102 #define MSGF_PRIORITY   0x0100          /* priority message */
 103 #define MSGF_RECEIPT    0x0200          /* need receipt after put done */
 104
 105 #define MSGF_USER0      0x00010000
 106 #define MSGF_USER1      0x00020000
 107 #define MSGF_USER2      0x00040000
 108 #define MSGF_USER3      0x00080000
 109
 110 #define MSG_CMD_CDEV    0x00010000
 111 #define MSG_CMD_VFS     0x00020000
 112 #define MSG_CMD_SYSCALL 0x00030000
 113 #define MSG_SUBCMD_MASK 0x0000FFFF
 114
 115 #ifdef _KERNEL
 116 MALLOC_DECLARE(M_LWKTMSG);
 117 #endif
 118
 119 /*
 120  * Notes on port processing requirements:
 121  *
 122  * mp_putport():
 123  *      - may return synchronous error code (error != EASYNC) directly and
 124  *        does not need to check or set MSGF_DONE if so, or set ms_target_port
 125  *      - for asynch procesing should clear MSGF_DONE and set ms_target_port
 126  *        to port prior to initiation of the command.
 127  *
 128  * mp_waitmsg():
 129  *      - wait for a particular message to be returned.
 130  *
 131  * mp_waitport():
 132  *      - wait for a new message on the specified port.
 133  *
 134  * mp_replyport():
 135  *      - reply a message (executed on the originating port to return a
 136  *        message to it).  This can be rather involved if abort is to be
 137  *        supported, see lwkt_default_replyport().  Generally speaking
 138  *        one sets MSGF_DONE and MSGF_REPLY.  If MSGF_SYNC is set the message
 139  *        is not queued to the port and the reply code wakes up the waiter
 140  *        directly.
 141  *
 142  * mp_dropmsg():
 143  *      - drop a specific message from the specified port.  Currently only
 144  *        threads' embedded ports (thread ports or spin ports) support this
 145  *        function and must be used in the port's owner thread.
 146  *        (returns 0 on success, ENOENT on error).
 147  *
 148  * The use of mpu_td and mp_u.spin is specific to the port callback function
 149  * set.  Default ports are tied to specific threads and use cpu locality
 150  * of reference and mpu_td (and not mp_u.spin at all).  Descriptor ports
 151  * assume access via descriptors, signal interruption, etc.  Such ports use
 152  * mp_u.spin (and not mpu_td at all) and may be accessed by multiple threads.
 153  *
 154  * Threads' embedded ports always have mpu_td back pointing to themselves.
 155  */
 156 typedef struct lwkt_port {
 157     lwkt_msg_queue      mp_msgq;
 158     lwkt_msg_queue      mp_msgq_prio;
 159     int                 mp_flags;
 160     int                 mp_cpuid;
 161     union {
 162         struct spinlock spin;
 163         struct lwkt_serialize *serialize;
 164         void            *data;
 165     } mp_u;
 166     struct thread       *mpu_td;
 167     void *              (*mp_getport)(lwkt_port_t);
 168     int                 (*mp_putport)(lwkt_port_t, lwkt_msg_t);
 169     int                 (*mp_waitmsg)(lwkt_msg_t, int flags);
 170     void *              (*mp_waitport)(lwkt_port_t, int flags);
 171     void                (*mp_replyport)(lwkt_port_t, lwkt_msg_t);
 172     int                 (*mp_dropmsg)(lwkt_port_t, lwkt_msg_t);
 173     int                 (*mp_putport_oncpu)(lwkt_port_t, lwkt_msg_t);
 174 } lwkt_port;
 175
 176 #ifdef _KERNEL
 177
 178 #define mpu_spin        mp_u.spin
 179 #define mpu_serialize   mp_u.serialize
 180 #define mpu_data        mp_u.data
 181
 182 /*
 183  * Port state flags.
 184  *
 185  * WAITING      The owner of the port is descheduled waiting for a message
 186  *              to be replied.  In case this a spin port there can actually
 187  *              be more than one thread waiting on the port.
 188  */
 189 #define MSGPORTF_WAITING        0x0001
 190
 191 /*
 192  * These functions are good for userland as well as the kernel.  The
 193  * messaging function support for userland is provided by the kernel's
 194  * kern/lwkt_msgport.c.  The port functions are provided by userland.
 195  */
 196
 197 void lwkt_initport_thread(lwkt_port_t, struct thread *);
 198 void lwkt_initport_spin(lwkt_port_t, struct thread *, boolean_t);
 199 void lwkt_initport_serialize(lwkt_port_t, struct lwkt_serialize *);
 200 void lwkt_initport_panic(lwkt_port_t);
 201 void lwkt_initport_replyonly_null(lwkt_port_t);
 202 void lwkt_initport_replyonly(lwkt_port_t,
 203                                 void (*rportfn)(lwkt_port_t, lwkt_msg_t));
 204 void lwkt_initport_putonly(lwkt_port_t,
 205                                 int (*pportfn)(lwkt_port_t, lwkt_msg_t));
 206
 207 void lwkt_sendmsg(lwkt_port_t, lwkt_msg_t);
 208 void lwkt_sendmsg_oncpu(lwkt_port_t, lwkt_msg_t);
 209 void lwkt_sendmsg_prepare(lwkt_port_t, lwkt_msg_t);
 210 void lwkt_sendmsg_start(lwkt_port_t, lwkt_msg_t);
 211 int lwkt_domsg(lwkt_port_t, lwkt_msg_t, int);
 212 int lwkt_forwardmsg(lwkt_port_t, lwkt_msg_t);
 213 void lwkt_abortmsg(lwkt_msg_t);
 214
 215 #endif /* _KERNEL */
 216
 217 #endif