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1 | /* |
1 | /* |
2 | * Copyright (C) 2006 Ondrej Palkovsky |
2 | * Copyright (C) 2006 Ondrej Palkovsky |
3 | * All rights reserved. |
3 | * All rights reserved. |
4 | * |
4 | * |
5 | * Redistribution and use in source and binary forms, with or without |
5 | * Redistribution and use in source and binary forms, with or without |
6 | * modification, are permitted provided that the following conditions |
6 | * modification, are permitted provided that the following conditions |
7 | * are met: |
7 | * are met: |
8 | * |
8 | * |
9 | * - Redistributions of source code must retain the above copyright |
9 | * - Redistributions of source code must retain the above copyright |
10 | * notice, this list of conditions and the following disclaimer. |
10 | * notice, this list of conditions and the following disclaimer. |
11 | * - Redistributions in binary form must reproduce the above copyright |
11 | * - Redistributions in binary form must reproduce the above copyright |
12 | * notice, this list of conditions and the following disclaimer in the |
12 | * notice, this list of conditions and the following disclaimer in the |
13 | * documentation and/or other materials provided with the distribution. |
13 | * documentation and/or other materials provided with the distribution. |
14 | * - The name of the author may not be used to endorse or promote products |
14 | * - The name of the author may not be used to endorse or promote products |
15 | * derived from this software without specific prior written permission. |
15 | * derived from this software without specific prior written permission. |
16 | * |
16 | * |
17 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR |
17 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR |
18 | * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES |
18 | * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES |
19 | * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. |
19 | * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. |
20 | * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, |
20 | * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, |
21 | * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT |
21 | * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT |
22 | * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
22 | * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
23 | * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
23 | * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
24 | * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
24 | * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
25 | * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF |
25 | * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF |
26 | * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
26 | * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
27 | */ |
27 | */ |
28 | 28 | ||
29 | /* IPC resources management |
29 | /* IPC resources management |
30 | * |
30 | * |
31 | * The goal of this source code is to properly manage IPC resources |
31 | * The goal of this source code is to properly manage IPC resources |
32 | * and allow straight and clean clean-up procedure upon task termination. |
32 | * and allow straight and clean clean-up procedure upon task termination. |
33 | * |
33 | * |
34 | * The pattern of usage of the resources is: |
34 | * The pattern of usage of the resources is: |
35 | * - allocate empty phone slot, connect | deallocate slot |
35 | * - allocate empty phone slot, connect | deallocate slot |
36 | * - disconnect connected phone (some messages might be on the fly) |
36 | * - disconnect connected phone (some messages might be on the fly) |
37 | * - find phone in slot and send a message using phone |
37 | * - find phone in slot and send a message using phone |
38 | * - answer message to phone |
38 | * - answer message to phone |
39 | * |
39 | * |
- | 40 | * Locking strategy |
|
- | 41 | * |
|
- | 42 | * - To use a phone, disconnect a phone etc., the phone must be |
|
- | 43 | * first locked and then checked that it is connected |
|
- | 44 | * - To connect an allocated phone it need not be locked (assigning |
|
- | 45 | * pointer is atomic on all platforms) |
|
- | 46 | * |
|
- | 47 | * - To find an empty phone slot, the TASK must be locked |
|
- | 48 | * - To answer a message, the answerbox must be locked |
|
- | 49 | * - The locking of phone and answerbox is done at the ipc_ level. |
|
- | 50 | * It is perfectly correct to pass unconnected phone to these functions |
|
- | 51 | * and proper reply will be generated. |
|
- | 52 | * |
|
- | 53 | * - There may be objection that a race may occur when the syscall finds |
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- | 54 | * an appropriate call and before executing ipc_send, the phone call might |
|
- | 55 | * be disconnected and connected elsewhere. As there is no easy solution, |
|
- | 56 | * the application will be notified by an 'PHONE_DISCONNECTED' message |
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- | 57 | * and the phone will not be allocated before the application notifies |
|
- | 58 | * the kernel subsystem that it does not have any pending calls regarding |
|
- | 59 | * this phone call. |
|
- | 60 | * |
|
- | 61 | * Locking order |
|
- | 62 | * |
|
- | 63 | * There are 2 possibilities |
|
- | 64 | * - first phone, then answerbox |
|
- | 65 | * + Easy locking on calls |
|
- | 66 | * - Very hard traversing list of phones when disconnecting because |
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- | 67 | * the phones may disconnect during traversal of list of connected phones. |
|
- | 68 | * The only possibility is try_lock with restart of list traversal. |
|
- | 69 | * |
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- | 70 | * - first answerbox, then phone(s) |
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- | 71 | * + Easy phone disconnect |
|
- | 72 | * - Multiple checks needed when sending message |
|
- | 73 | * |
|
- | 74 | * Because the answerbox destroyal is much less frequent operation, |
|
- | 75 | * the first method is chosen. |
|
- | 76 | * |
|
- | 77 | * Cleanup strategy |
|
- | 78 | * |
|
- | 79 | * 1) Disconnect all phones. |
|
- | 80 | * * Send message 'PHONE_DISCONNECTED' to the target application |
|
- | 81 | * - Once all phones are disconnected, no further calls can arrive |
|
- | 82 | * |
|
- | 83 | * 2) Answer all messages in 'calls' and 'dispatched_calls' queues with |
|
- | 84 | * appropriate error code. |
|
- | 85 | * |
|
- | 86 | * 3) Wait for all async answers to arrive |
|
- | 87 | * Alternatively - we might try to invalidate all messages by setting some |
|
- | 88 | * flag, that would dispose of the message once it is answered. This |
|
- | 89 | * would need to link all calls in one big list, which we don't currently |
|
- | 90 | * do. |
|
- | 91 | * |
|
40 | * |
92 | * |
41 | */ |
93 | */ |
42 | 94 | ||
43 | #include <synch/spinlock.h> |
95 | #include <synch/spinlock.h> |
44 | #include <ipc/ipc.h> |
96 | #include <ipc/ipc.h> |
45 | #include <arch.h> |
97 | #include <arch.h> |
46 | #include <proc/task.h> |
98 | #include <proc/task.h> |
47 | #include <ipc/ipcrsc.h> |
99 | #include <ipc/ipcrsc.h> |
48 | #include <debug.h> |
100 | #include <debug.h> |
49 | 101 | ||
50 | /** Find call_t * in call table according to callid |
102 | /** Find call_t * in call table according to callid |
51 | * |
103 | * |
52 | * @return NULL on not found, otherwise pointer to call structure |
104 | * @return NULL on not found, otherwise pointer to call structure |
53 | */ |
105 | */ |
54 | call_t * get_call(__native callid) |
106 | call_t * get_call(__native callid) |
55 | { |
107 | { |
56 | /* TODO: Traverse list of dispatched calls and find one */ |
108 | /* TODO: Traverse list of dispatched calls and find one */ |
57 | /* TODO: locking of call, ripping it from dispatched calls etc. */ |
109 | /* TODO: locking of call, ripping it from dispatched calls etc. */ |
58 | return (call_t *) callid; |
110 | return (call_t *) callid; |
59 | } |
111 | } |
60 | 112 | ||
61 | /** Return pointer to phone identified by phoneid or NULL if non-existent */ |
- | |
62 | phone_t * get_phone_and_lock(__native phoneid) |
- | |
63 | { |
- | |
64 | phone_t *phone; |
- | |
65 | - | ||
66 | if (phoneid >= IPC_MAX_PHONES) |
- | |
67 | return NULL; |
- | |
68 | - | ||
69 | phone = &TASK->phones[phoneid]; |
- | |
70 | spinlock_lock(&phone->lock); |
- | |
71 | if (!phone->callee) { |
- | |
72 | spinlock_unlock(&phone->lock); |
- | |
73 | return NULL; |
- | |
74 | } |
- | |
75 | /* TODO... */ |
- | |
76 | spinlock_unlock(&phone->lock); |
- | |
77 | return phone; |
- | |
78 | } |
- | |
79 | - | ||
80 | /** Allocate new phone slot in current TASK structure */ |
113 | /** Allocate new phone slot in current TASK structure */ |
81 | int phone_alloc(void) |
114 | int phone_alloc(void) |
82 | { |
115 | { |
83 | int i; |
116 | int i; |
84 | 117 | ||
85 | spinlock_lock(&TASK->lock); |
118 | spinlock_lock(&TASK->lock); |
86 | 119 | ||
87 | for (i=0; i < IPC_MAX_PHONES; i++) { |
120 | for (i=0; i < IPC_MAX_PHONES; i++) { |
88 | if (!TASK->phones[i].busy) { |
121 | if (!TASK->phones[i].busy) { |
89 | TASK->phones[i].busy = 1; |
122 | TASK->phones[i].busy = 1; |
90 | break; |
123 | break; |
91 | } |
124 | } |
92 | } |
125 | } |
93 | spinlock_unlock(&TASK->lock); |
126 | spinlock_unlock(&TASK->lock); |
94 | 127 | ||
95 | if (i >= IPC_MAX_PHONES) |
128 | if (i >= IPC_MAX_PHONES) |
96 | return -1; |
129 | return -1; |
97 | return i; |
130 | return i; |
98 | } |
131 | } |
99 | 132 | ||
100 | /** Disconnect phone */ |
133 | /** Disconnect phone */ |
101 | void phone_dealloc(int phoneid) |
134 | void phone_dealloc(int phoneid) |
102 | { |
135 | { |
103 | spinlock_lock(&TASK->lock); |
136 | spinlock_lock(&TASK->lock); |
104 | 137 | ||
105 | ASSERT(TASK->phones[phoneid].busy); |
138 | ASSERT(TASK->phones[phoneid].busy); |
106 | 139 | ||
107 | if (TASK->phones[phoneid].callee) |
140 | if (TASK->phones[phoneid].callee) |
108 | ipc_phone_destroy(&TASK->phones[phoneid]); |
141 | ipc_phone_destroy(&TASK->phones[phoneid]); |
109 | 142 | ||
110 | TASK->phones[phoneid].busy = 0; |
143 | TASK->phones[phoneid].busy = 0; |
111 | spinlock_unlock(&TASK->lock); |
144 | spinlock_unlock(&TASK->lock); |
112 | } |
145 | } |
113 | 146 | ||
- | 147 | /** Connect phone to a given answerbox |
|
- | 148 | * |
|
- | 149 | * @param phoneid The slot that will be connected |
|
- | 150 | * |
|
- | 151 | * The procedure _enforces_ that the user first marks the phone |
|
- | 152 | * busy (e.g. via phone_alloc) and then connects the phone, otherwise |
|
- | 153 | * race condition may appear. |
|
- | 154 | */ |
|
114 | void phone_connect(int phoneid, answerbox_t *box) |
155 | void phone_connect(int phoneid, answerbox_t *box) |
115 | { |
156 | { |
116 | phone_t *phone = &TASK->phones[phoneid]; |
157 | phone_t *phone = &TASK->phones[phoneid]; |
117 | 158 | ||
- | 159 | ASSERT(phone->busy); |
|
118 | ipc_phone_connect(phone, box); |
160 | ipc_phone_connect(phone, box); |
119 | } |
161 | } |
120 | 162 |