Commit | Line | Data |
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1da177e4 LT |
1 | /* |
2 | * linux/arch/m68k/mm/fault.c | |
3 | * | |
4 | * Copyright (C) 1995 Hamish Macdonald | |
5 | */ | |
6 | ||
7 | #include <linux/mman.h> | |
8 | #include <linux/mm.h> | |
9 | #include <linux/kernel.h> | |
10 | #include <linux/ptrace.h> | |
11 | #include <linux/interrupt.h> | |
12 | #include <linux/module.h> | |
13 | ||
14 | #include <asm/setup.h> | |
15 | #include <asm/traps.h> | |
16 | #include <asm/system.h> | |
17 | #include <asm/uaccess.h> | |
18 | #include <asm/pgalloc.h> | |
19 | ||
20 | extern void die_if_kernel(char *, struct pt_regs *, long); | |
1da177e4 LT |
21 | |
22 | int send_fault_sig(struct pt_regs *regs) | |
23 | { | |
24 | siginfo_t siginfo = { 0, 0, 0, }; | |
25 | ||
26 | siginfo.si_signo = current->thread.signo; | |
27 | siginfo.si_code = current->thread.code; | |
28 | siginfo.si_addr = (void *)current->thread.faddr; | |
29 | #ifdef DEBUG | |
30 | printk("send_fault_sig: %p,%d,%d\n", siginfo.si_addr, siginfo.si_signo, siginfo.si_code); | |
31 | #endif | |
32 | ||
33 | if (user_mode(regs)) { | |
34 | force_sig_info(siginfo.si_signo, | |
35 | &siginfo, current); | |
36 | } else { | |
dcdf3a29 | 37 | if (handle_kernel_fault(regs)) |
1da177e4 | 38 | return -1; |
1da177e4 LT |
39 | |
40 | //if (siginfo.si_signo == SIGBUS) | |
41 | // force_sig_info(siginfo.si_signo, | |
42 | // &siginfo, current); | |
43 | ||
44 | /* | |
45 | * Oops. The kernel tried to access some bad page. We'll have to | |
46 | * terminate things with extreme prejudice. | |
47 | */ | |
48 | if ((unsigned long)siginfo.si_addr < PAGE_SIZE) | |
49 | printk(KERN_ALERT "Unable to handle kernel NULL pointer dereference"); | |
50 | else | |
51 | printk(KERN_ALERT "Unable to handle kernel access"); | |
52 | printk(" at virtual address %p\n", siginfo.si_addr); | |
53 | die_if_kernel("Oops", regs, 0 /*error_code*/); | |
54 | do_exit(SIGKILL); | |
55 | } | |
56 | ||
57 | return 1; | |
58 | } | |
59 | ||
60 | /* | |
61 | * This routine handles page faults. It determines the problem, and | |
62 | * then passes it off to one of the appropriate routines. | |
63 | * | |
64 | * error_code: | |
65 | * bit 0 == 0 means no page found, 1 means protection fault | |
66 | * bit 1 == 0 means read, 1 means write | |
67 | * | |
68 | * If this routine detects a bad access, it returns 1, otherwise it | |
69 | * returns 0. | |
70 | */ | |
71 | int do_page_fault(struct pt_regs *regs, unsigned long address, | |
72 | unsigned long error_code) | |
73 | { | |
74 | struct mm_struct *mm = current->mm; | |
75 | struct vm_area_struct * vma; | |
76 | int write, fault; | |
77 | ||
78 | #ifdef DEBUG | |
79 | printk ("do page fault:\nregs->sr=%#x, regs->pc=%#lx, address=%#lx, %ld, %p\n", | |
80 | regs->sr, regs->pc, address, error_code, | |
81 | current->mm->pgd); | |
82 | #endif | |
83 | ||
84 | /* | |
85 | * If we're in an interrupt or have no user | |
86 | * context, we must not take the fault.. | |
87 | */ | |
6edaf68a | 88 | if (in_atomic() || !mm) |
1da177e4 LT |
89 | goto no_context; |
90 | ||
91 | down_read(&mm->mmap_sem); | |
92 | ||
93 | vma = find_vma(mm, address); | |
94 | if (!vma) | |
95 | goto map_err; | |
96 | if (vma->vm_flags & VM_IO) | |
97 | goto acc_err; | |
98 | if (vma->vm_start <= address) | |
99 | goto good_area; | |
100 | if (!(vma->vm_flags & VM_GROWSDOWN)) | |
101 | goto map_err; | |
102 | if (user_mode(regs)) { | |
103 | /* Accessing the stack below usp is always a bug. The | |
104 | "+ 256" is there due to some instructions doing | |
105 | pre-decrement on the stack and that doesn't show up | |
106 | until later. */ | |
107 | if (address + 256 < rdusp()) | |
108 | goto map_err; | |
109 | } | |
110 | if (expand_stack(vma, address)) | |
111 | goto map_err; | |
112 | ||
113 | /* | |
114 | * Ok, we have a good vm_area for this memory access, so | |
115 | * we can handle it.. | |
116 | */ | |
117 | good_area: | |
118 | #ifdef DEBUG | |
119 | printk("do_page_fault: good_area\n"); | |
120 | #endif | |
121 | write = 0; | |
122 | switch (error_code & 3) { | |
123 | default: /* 3: write, present */ | |
124 | /* fall through */ | |
125 | case 2: /* write, not present */ | |
126 | if (!(vma->vm_flags & VM_WRITE)) | |
127 | goto acc_err; | |
128 | write++; | |
129 | break; | |
130 | case 1: /* read, present */ | |
131 | goto acc_err; | |
132 | case 0: /* read, not present */ | |
df67b3da | 133 | if (!(vma->vm_flags & (VM_READ | VM_EXEC | VM_WRITE))) |
1da177e4 LT |
134 | goto acc_err; |
135 | } | |
136 | ||
137 | /* | |
138 | * If for any reason at all we couldn't handle the fault, | |
139 | * make sure we exit gracefully rather than endlessly redo | |
140 | * the fault. | |
141 | */ | |
142 | ||
d06063cc | 143 | fault = handle_mm_fault(mm, vma, address, write ? FAULT_FLAG_WRITE : 0); |
1da177e4 LT |
144 | #ifdef DEBUG |
145 | printk("handle_mm_fault returns %d\n",fault); | |
146 | #endif | |
83c54070 NP |
147 | if (unlikely(fault & VM_FAULT_ERROR)) { |
148 | if (fault & VM_FAULT_OOM) | |
149 | goto out_of_memory; | |
150 | else if (fault & VM_FAULT_SIGBUS) | |
151 | goto bus_err; | |
152 | BUG(); | |
1da177e4 | 153 | } |
83c54070 NP |
154 | if (fault & VM_FAULT_MAJOR) |
155 | current->maj_flt++; | |
156 | else | |
157 | current->min_flt++; | |
1da177e4 LT |
158 | |
159 | up_read(&mm->mmap_sem); | |
160 | return 0; | |
161 | ||
162 | /* | |
163 | * We ran out of memory, or some other thing happened to us that made | |
164 | * us unable to handle the page fault gracefully. | |
165 | */ | |
166 | out_of_memory: | |
167 | up_read(&mm->mmap_sem); | |
adbf6e69 NP |
168 | if (!user_mode(regs)) |
169 | goto no_context; | |
170 | pagefault_out_of_memory(); | |
171 | return 0; | |
1da177e4 LT |
172 | |
173 | no_context: | |
174 | current->thread.signo = SIGBUS; | |
175 | current->thread.faddr = address; | |
176 | return send_fault_sig(regs); | |
177 | ||
178 | bus_err: | |
179 | current->thread.signo = SIGBUS; | |
180 | current->thread.code = BUS_ADRERR; | |
181 | current->thread.faddr = address; | |
182 | goto send_sig; | |
183 | ||
184 | map_err: | |
185 | current->thread.signo = SIGSEGV; | |
186 | current->thread.code = SEGV_MAPERR; | |
187 | current->thread.faddr = address; | |
188 | goto send_sig; | |
189 | ||
190 | acc_err: | |
191 | current->thread.signo = SIGSEGV; | |
192 | current->thread.code = SEGV_ACCERR; | |
193 | current->thread.faddr = address; | |
194 | ||
195 | send_sig: | |
196 | up_read(&mm->mmap_sem); | |
197 | return send_fault_sig(regs); | |
198 | } |