Subversion Repositories HelenOS

Rev

Rev 3094 | Go to most recent revision | Details | Compare with Previous | Last modification | View Log | RSS feed

Rev Author Line No. Line
2464 jermar 1
/*
2
 * Copyright (c) 2007 Pavel Jancik, Michal Kebrt
3
 * All rights reserved.
4
 *
5
 * Redistribution and use in source and binary forms, with or without
6
 * modification, are permitted provided that the following conditions
7
 * are met:
8
 *
9
 * - Redistributions of source code must retain the above copyright
10
 *   notice, this list of conditions and the following disclaimer.
11
 * - Redistributions in binary form must reproduce the above copyright
12
 *   notice, this list of conditions and the following disclaimer in the
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
15
 *   derived from this software without specific prior written permission.
16
 *
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
19
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
20
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
21
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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
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
26
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27
 */
28
 
29
/** @addtogroup arm32mm
30
 * @{
31
 */
32
/** @file
33
 *  @brief Page fault related functions.
34
 */
35
#include <panic.h>
36
#include <arch/exception.h>
37
#include <arch/debug/print.h>
38
#include <arch/mm/page_fault.h>
39
#include <mm/as.h>
40
#include <genarch/mm/page_pt.h>
41
#include <arch.h>
42
#include <interrupt.h>
3094 svoboda 43
#include <print.h>
2464 jermar 44
 
45
/** Returns value stored in fault status register.
46
 *
47
 *  @return Value stored in CP15 fault status register (FSR).
48
 */
49
static inline fault_status_t read_fault_status_register(void)
50
{
51
    fault_status_union_t fsu;
52
 
53
    /* fault status is stored in CP15 register 5 */
54
    asm volatile (
55
        "mrc p15, 0, %0, c5, c0, 0"
56
        : "=r"(fsu.dummy)
57
    );
58
    return fsu.fs;
59
}
60
 
61
/** Returns FAR (fault address register) content.
62
 *
63
 * @return FAR (fault address register) content (address that caused a page
64
 *     fault)
65
 */
66
static inline uintptr_t read_fault_address_register(void)
67
{
68
    uintptr_t ret;
69
 
70
    /* fault adress is stored in CP15 register 6 */
71
    asm volatile (
72
        "mrc p15, 0, %0, c6, c0, 0"
73
        : "=r"(ret)
74
    );
75
    return ret;
76
}
77
 
78
/** Decides whether the instruction is load/store or not.
79
 *
80
 * @param instr Instruction
81
 *
82
 * @return true when instruction is load/store, false otherwise
83
 */
84
static inline bool is_load_store_instruction(instruction_t instr)
85
{
86
    /* load store immediate offset */
87
    if (instr.type == 0x2) {
88
        return true;
89
    }
90
 
91
    /* load store register offset */
92
    if (instr.type == 0x3 && instr.bit4 == 0) {
93
        return true;
94
    }
95
 
96
    /* load store multiple */
97
    if (instr.type == 0x4) {
98
        return true;
99
    }
100
 
101
    /* oprocessor load/store */
102
    if (instr.type == 0x6) {
103
        return true;
104
    }
105
 
106
    return false;
107
}
108
 
109
/** Decides whether the instruction is swap or not.
110
 *
111
 * @param instr Instruction
112
 *
113
 * @return true when instruction is swap, false otherwise
114
 */
115
static inline bool is_swap_instruction(instruction_t instr)
116
{
117
    /* swap, swapb instruction */
118
    if (instr.type == 0x0 &&
119
        (instr.opcode == 0x8 || instr.opcode == 0xa) &&
120
        instr.access == 0x0 && instr.bits567 == 0x4 && instr.bit4 == 1) {
121
        return true;
122
    }
123
 
124
    return false;
125
}
126
 
127
/** Decides whether read or write into memory is requested.
128
 *
129
 * @param instr_addr   Address of instruction which tries to access memory.
130
 * @param badvaddr     Virtual address the instruction tries to access.
131
 *
132
 * @return Type of access into memory, PF_ACCESS_EXEC if no memory access is
133
 *     requested.
134
 */
135
static pf_access_t get_memory_access_type(uint32_t instr_addr,
136
    uintptr_t badvaddr)
137
{
138
    instruction_union_t instr_union;
139
    instr_union.pc = instr_addr;
140
 
141
    instruction_t instr = *(instr_union.instr);
142
 
143
    /* undefined instructions */
144
    if (instr.condition == 0xf) {
145
        panic("page_fault - instruction doesn't access memory "
146
            "(instr_code: %x, badvaddr:%x)", instr, badvaddr);
147
        return PF_ACCESS_EXEC;
148
    }
149
 
150
    /* load store instructions */
151
    if (is_load_store_instruction(instr)) {
152
        if (instr.access == 1) {
153
            return PF_ACCESS_READ;
154
        } else {
155
            return PF_ACCESS_WRITE;
156
        }
157
    }
158
 
159
    /* swap, swpb instruction */
160
    if (is_swap_instruction(instr)) {
161
        return PF_ACCESS_WRITE;
162
    }
163
 
164
    panic("page_fault - instruction doesn't access memory "
165
        "(instr_code: %x, badvaddr:%x)", instr, badvaddr);
166
 
167
    return PF_ACCESS_EXEC;
168
}
169
 
170
/** Handles "data abort" exception (load or store at invalid address).
171
 *
172
 * @param exc_no    Exception number.
173
 * @param istate    CPU state when exception occured.
174
 */
175
void data_abort(int exc_no, istate_t *istate)
176
{
2772 jermar 177
    fault_status_t fsr __attribute__ ((unused)) =
178
        read_fault_status_register();
2464 jermar 179
    uintptr_t badvaddr = read_fault_address_register();
180
 
181
    pf_access_t access = get_memory_access_type(istate->pc, badvaddr);
182
 
183
    int ret = as_page_fault(badvaddr, access, istate);
184
 
185
    if (ret == AS_PF_FAULT) {
186
        print_istate(istate);
187
        dprintf("page fault - pc: %x, va: %x, status: %x(%x), "
188
            "access:%d\n", istate->pc, badvaddr, fsr.status, fsr,
189
            access);
190
 
191
        fault_if_from_uspace(istate, "Page fault: %#x", badvaddr);
192
        panic("page fault\n");
193
    }
194
}
195
 
196
/** Handles "prefetch abort" exception (instruction couldn't be executed).
197
 *
198
 * @param exc_no    Exception number.
199
 * @param istate    CPU state when exception occured.
200
 */
201
void prefetch_abort(int exc_no, istate_t *istate)
202
{
203
    int ret = as_page_fault(istate->pc, PF_ACCESS_EXEC, istate);
204
 
205
    if (ret == AS_PF_FAULT) {
206
        dprintf("prefetch_abort\n");
207
        print_istate(istate);
208
        panic("page fault - prefetch_abort at address: %x\n",
209
            istate->pc);
210
    }
211
}
212
 
213
/** @}
214
 */