git.barrelfish.org Git - barrelfish/blob - include/flounder/flounder_support_ump.h

   1 /**
   2  * \file
   3  * \brief Prototypes for use by flounder-generated stubs
   4  */
   5
   6 /*
   7  * Copyright (c) 2010, ETH Zurich.
   8  * All rights reserved.
   9  *
  10  * This file is distributed under the terms in the attached LICENSE file.
  11  * If you do not find this file, copies can be found by writing to:
  12  * ETH Zurich D-INFK, Haldeneggsteig 4, CH-8092 Zurich. Attn: Systems Group.
  13  */
  14
  15 #ifndef __FLOUNDER_SUPPORT_UMP_H
  16 #define __FLOUNDER_SUPPORT_UMP_H
  17
  18 #include <sys/cdefs.h>
  19
  20 #include <barrelfish/ump_chan.h>
  21 #include <flounder/flounder_support_caps.h>
  22 #include <trace/trace.h>
  23
  24 __BEGIN_DECLS
  25
  26 /// Number of bits available for the message type in the header
  27 #define FL_UMP_MSGTYPE_BITS (UMP_HEADER_BITS - UMP_INDEX_BITS)
  28
  29 /// Special message types
  30 enum flounder_ump_msgtype {
  31     FL_UMP_ACK = 0,
  32     FL_UMP_BIND = 1,
  33     FL_UMP_BIND_REPLY = 2,
  34     FL_UMP_CAP_ACK = (1 << FL_UMP_MSGTYPE_BITS) - 1,
  35 };
  36
  37 struct flounder_ump_state {
  38     struct ump_chan chan;
  39
  40     ump_index_t next_id;   ///< Sequence number of next message to be sent
  41     ump_index_t seq_id;    ///< Last sequence number received from remote
  42     ump_index_t ack_id;    ///< Last sequence number acknowledged by remote
  43     ump_index_t last_ack;  ///< Last acknowledgement we sent to remote
  44
  45     struct flounder_cap_state capst; ///< State for indirect cap tx/rx machinery
  46     uint32_t token;        ///< Outgoing message's token
  47 };
  48
  49 void flounder_stub_ump_state_init(struct flounder_ump_state *s, void *binding);
  50
  51 errval_t flounder_stub_ump_send_string(struct flounder_ump_state *s,
  52                                        int msgnum, const char *str,
  53                                        size_t *pos, size_t *len);
  54
  55 errval_t flounder_stub_ump_recv_string(volatile struct ump_message *msg,
  56                                        char *str, size_t *pos, size_t *len,
  57                                        size_t maxsize);
  58
  59 errval_t flounder_stub_ump_send_buf(struct flounder_ump_state *s,
  60                                        int msgnum, const void *buf,
  61                                        size_t len, size_t *pos);
  62
  63 errval_t flounder_stub_ump_recv_buf(volatile struct ump_message *msg,
  64                                     void *buf, size_t *len, size_t *pos,
  65                                     size_t maxsize);
  66
  67
  68 /// Computes (from seq/ack numbers) whether we can currently send on the channel
  69 static inline bool flounder_stub_ump_can_send(struct flounder_ump_state *s) {
  70     bool r = (ump_index_t)(s->next_id - s->ack_id) <= s->chan.max_send_msgs;
  71     return r;
  72 }
  73
  74 #define ENABLE_MESSAGE_PASSING_TRACE 1
  75 /// Prepare a "control" word (header for each UMP message fragment)
  76 static inline void flounder_stub_ump_control_fill(struct flounder_ump_state *s,
  77                                                   struct ump_control *ctrl,
  78                                                   int msgtype)
  79 {
  80 #if ENABLE_MESSAGE_PASSING_TRACE
  81     trace_event_raw((((uint64_t)0xEA)<<56) |
  82                     ((uint64_t)s->chan.sendid << 12) |
  83                     (s->next_id & 0xffff));
  84 #endif // ENABLE_MESSAGE_PASSING_TRACE
  85     assert(s->chan.sendid != 0);
  86     assert(msgtype < (1 << FL_UMP_MSGTYPE_BITS)); // check for overflow
  87     ctrl->header = ((uintptr_t)msgtype << UMP_INDEX_BITS) | (uintptr_t)s->seq_id;
  88     ctrl->token = s->token;
  89     s->last_ack = s->seq_id;
  90     s->next_id++;
  91 }
  92
  93 /// Process a "control" word
  94 static inline int flounder_stub_ump_control_process(struct flounder_ump_state *s,
  95                                                     struct ump_control ctrl)
  96 {
  97 #if ENABLE_MESSAGE_PASSING_TRACE
  98     trace_event_raw( (((uint64_t)0xEB)<<56) |
  99                      ((uint64_t)s->chan.recvid << 12) |
 100                      (s->seq_id & 0xffff));
 101 #endif // ENABLE_MESSAGE_PASSING_TRACE
 102     s->ack_id = ctrl.header & UMP_INDEX_MASK;
 103     s->seq_id++;
 104     return ctrl.header >> UMP_INDEX_BITS;
 105 }
 106
 107 /// Emit memory barrier needed between writing UMP payload and header
 108 static inline void flounder_stub_ump_barrier(void)
 109 {
 110 #if defined(__i386__) || defined(__x86_64__)
 111     /* the x86 memory model ensures ordering of stores, so all we need to do
 112      * is prevent the compiler from reordering the instructions */
 113     __asm volatile ("" : : : "memory");
 114 #else
 115     /* use conservative GCC intrinsic */
 116     __sync_synchronize();
 117 #endif
 118 }
 119
 120 /// Should we send an ACK?
 121 static inline bool flounder_stub_ump_needs_ack(struct flounder_ump_state *s)
 122 {
 123     // send a forced ACK if the channel is full
 124     // FIXME: should probably send it only when "nearly" full
 125     return (ump_index_t)(s->seq_id - s->last_ack) >=
 126         (ump_index_t)(s->chan.max_recv_msgs - 1);
 127 }
 128 /// Send an explicit ACK
 129 static inline void flounder_stub_ump_send_ack(struct flounder_ump_state *s)
 130 {
 131     assert(flounder_stub_ump_can_send(s));
 132     struct ump_control ctrl;
 133     volatile struct ump_message *msg = ump_chan_get_next(&s->chan, &ctrl);
 134     flounder_stub_ump_control_fill(s, &ctrl, FL_UMP_ACK);
 135     msg->header.control = ctrl;
 136 }
 137
 138 /// Send a cap ACK (message that we are ready to receive caps)
 139 static inline void flounder_stub_ump_send_cap_ack(struct flounder_ump_state *s)
 140 {
 141     assert(flounder_stub_ump_can_send(s));
 142     struct ump_control ctrl;
 143     volatile struct ump_message *msg = ump_chan_get_next(&s->chan, &ctrl);
 144     flounder_stub_ump_control_fill(s, &ctrl, FL_UMP_CAP_ACK);
 145     msg->header.control = ctrl;
 146 }
 147
 148 __END_DECLS
 149
 150 #endif // __FLOUNDER_SUPPORT_UMP_H