1/*
2 * Copyright (c) 2013-2019 Huawei Technologies Co., Ltd. All rights reserved.
3 * Copyright (c) 2020-2021 Huawei Device Co., Ltd. All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without modification,
6 * are permitted provided that the following conditions are met:
7 *
8 * 1. Redistributions of source code must retain the above copyright notice, this list of
9 *    conditions and the following disclaimer.
10 *
11 * 2. Redistributions in binary form must reproduce the above copyright notice, this list
12 *    of conditions and the following disclaimer in the documentation and/or other materials
13 *    provided with the distribution.
14 *
15 * 3. Neither the name of the copyright holder nor the names of its contributors may be used
16 *    to endorse or promote products derived from this software without specific prior written
17 *    permission.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
20 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
21 * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
22 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR
23 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
24 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
25 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
26 * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
27 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
28 * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
29 * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
30 */
31
32#include "los_exchook.h"
33#include "los_context.h"
34
35#ifndef LOSCFG_BASE_EXC_HOOK_LIMIT
36#define LOSCFG_BASE_EXC_HOOK_LIMIT  16
37#endif
38
39struct Node {
40    ExcHookFn excHookFn;
41    struct Node *next;
42};
43
44STATIC struct Node g_excNodes[LOSCFG_BASE_EXC_HOOK_LIMIT];
45STATIC struct Node *g_excHeads[EXC_TYPE_END + 1]; /* EXC_TYPE_END is used for the free list. */
46
47STATIC VOID DoExcHookInRegOrder(EXC_TYPE excType, struct Node *node)
48{
49    if (node != NULL) {
50        DoExcHookInRegOrder(excType, node->next);
51        node->excHookFn(excType);
52    }
53}
54
55STATIC VOID DoExcHook(EXC_TYPE excType)
56{
57    UINT32 intSave;
58    if (excType >= EXC_TYPE_END) {
59        return;
60    }
61    intSave = LOS_IntLock();
62    DoExcHookInRegOrder(excType, g_excHeads[excType]);
63    LOS_IntRestore(intSave);
64}
65
66STATIC struct Node *GetFreeNode(VOID)
67{
68    struct Node *node = NULL;
69    int i;
70    if (g_excHeads[EXC_TYPE_END] == NULL) {
71        if (g_excNodes[0].excHookFn != NULL) {
72            /* no free node now */
73            return NULL;
74        } else {
75            /* Initialize the free list */
76            for (i = 0; i < LOSCFG_BASE_EXC_HOOK_LIMIT; ++i) {
77                g_excNodes[i].next = g_excHeads[EXC_TYPE_END];
78                g_excHeads[EXC_TYPE_END] = &g_excNodes[i];
79            }
80            OsExcHookRegister(DoExcHook);
81        }
82    }
83
84    node = g_excHeads[EXC_TYPE_END];
85    g_excHeads[EXC_TYPE_END] = node->next;
86    return node;
87}
88
89UINT32 LOS_RegExcHook(EXC_TYPE excType, ExcHookFn excHookFn)
90{
91    UINT32 intSave;
92    struct Node *node = NULL;
93    if (excType >= EXC_TYPE_END || excHookFn == NULL) {
94        return LOS_ERRNO_SYS_PTR_NULL;
95    }
96
97    intSave = LOS_IntLock();
98    node = GetFreeNode();
99    if (node == NULL) {
100        LOS_IntRestore(intSave);
101        return LOS_ERRNO_SYS_HOOK_IS_FULL;
102    }
103
104    node->excHookFn = excHookFn;
105    node->next = g_excHeads[excType];
106    g_excHeads[excType] = node;
107    LOS_IntRestore(intSave);
108    return LOS_OK;
109}
110
111UINT32 LOS_UnRegExcHook(EXC_TYPE excType, ExcHookFn excHookFn)
112{
113    UINT32 intSave;
114    struct Node *node = NULL;
115    struct Node *preNode = NULL;
116    if (excType >= EXC_TYPE_END || excHookFn == NULL) {
117        return LOS_ERRNO_SYS_PTR_NULL;
118    }
119
120    intSave = LOS_IntLock();
121    for (node = g_excHeads[excType]; node != NULL; node = node->next) {
122        if (node->excHookFn == excHookFn) {
123            if (preNode) {
124                preNode->next = node->next;
125            } else {
126                g_excHeads[excType] = node->next;
127            }
128            node->excHookFn = NULL;
129            node->next = g_excHeads[EXC_TYPE_END];
130            g_excHeads[EXC_TYPE_END] = node;
131        }
132        preNode = node;
133    }
134    LOS_IntRestore(intSave);
135    return LOS_OK;
136}
137