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10#include <linux/signal.h>
11#include <linux/interrupt.h>
12#include <linux/sched.h>
13#include <linux/errno.h>
14#include <linux/ptrace.h>
15#include <linux/uaccess.h>
16#include <linux/kdebug.h>
17#include <asm/pgalloc.h>
18#include <asm/mmu.h>
19
20static int handle_vmalloc_fault(unsigned long address)
21{
22
23
24
25
26 pgd_t *pgd, *pgd_k;
27 pud_t *pud, *pud_k;
28 pmd_t *pmd, *pmd_k;
29
30 pgd = pgd_offset_fast(current->active_mm, address);
31 pgd_k = pgd_offset_k(address);
32
33 if (!pgd_present(*pgd_k))
34 goto bad_area;
35
36 pud = pud_offset(pgd, address);
37 pud_k = pud_offset(pgd_k, address);
38 if (!pud_present(*pud_k))
39 goto bad_area;
40
41 pmd = pmd_offset(pud, address);
42 pmd_k = pmd_offset(pud_k, address);
43 if (!pmd_present(*pmd_k))
44 goto bad_area;
45
46 set_pmd(pmd, *pmd_k);
47
48
49 return 0;
50
51bad_area:
52 return 1;
53}
54
55void do_page_fault(unsigned long address, struct pt_regs *regs)
56{
57 struct vm_area_struct *vma = NULL;
58 struct task_struct *tsk = current;
59 struct mm_struct *mm = tsk->mm;
60 siginfo_t info;
61 int fault, ret;
62 int write = regs->ecr_cause & ECR_C_PROTV_STORE;
63 unsigned int flags = FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE;
64
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74 if (address >= VMALLOC_START && address <= VMALLOC_END) {
75 ret = handle_vmalloc_fault(address);
76 if (unlikely(ret))
77 goto bad_area_nosemaphore;
78 else
79 return;
80 }
81
82 info.si_code = SEGV_MAPERR;
83
84
85
86
87
88 if (in_atomic() || !mm)
89 goto no_context;
90
91 if (user_mode(regs))
92 flags |= FAULT_FLAG_USER;
93retry:
94 down_read(&mm->mmap_sem);
95 vma = find_vma(mm, address);
96 if (!vma)
97 goto bad_area;
98 if (vma->vm_start <= address)
99 goto good_area;
100 if (!(vma->vm_flags & VM_GROWSDOWN))
101 goto bad_area;
102 if (expand_stack(vma, address))
103 goto bad_area;
104
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108
109good_area:
110 info.si_code = SEGV_ACCERR;
111
112
113
114 if ((regs->ecr_vec == ECR_V_PROTV) &&
115 (regs->ecr_cause == ECR_C_PROTV_INST_FETCH))
116 goto bad_area;
117
118 if (write) {
119 if (!(vma->vm_flags & VM_WRITE))
120 goto bad_area;
121 flags |= FAULT_FLAG_WRITE;
122 } else {
123 if (!(vma->vm_flags & (VM_READ | VM_EXEC)))
124 goto bad_area;
125 }
126
127
128
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130
131
132 fault = handle_mm_fault(mm, vma, address, flags);
133
134
135 if (unlikely(fatal_signal_pending(current))) {
136 if ((fault & VM_FAULT_ERROR) && !(fault & VM_FAULT_RETRY))
137 up_read(&mm->mmap_sem);
138 if (user_mode(regs))
139 return;
140 }
141
142 if (likely(!(fault & VM_FAULT_ERROR))) {
143 if (flags & FAULT_FLAG_ALLOW_RETRY) {
144
145 if (fault & VM_FAULT_MAJOR)
146 tsk->maj_flt++;
147 else
148 tsk->min_flt++;
149
150 if (fault & VM_FAULT_RETRY) {
151 flags &= ~FAULT_FLAG_ALLOW_RETRY;
152 flags |= FAULT_FLAG_TRIED;
153 goto retry;
154 }
155 }
156
157
158 up_read(&mm->mmap_sem);
159 return;
160 }
161
162
163 if (fault & VM_FAULT_OOM)
164 goto out_of_memory;
165 else if (fault & VM_FAULT_SIGBUS)
166 goto do_sigbus;
167
168
169 BUG();
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174
175bad_area:
176 up_read(&mm->mmap_sem);
177
178bad_area_nosemaphore:
179
180 if (user_mode(regs)) {
181 tsk->thread.fault_address = address;
182 info.si_signo = SIGSEGV;
183 info.si_errno = 0;
184
185 info.si_addr = (void __user *)address;
186 force_sig_info(SIGSEGV, &info, tsk);
187 return;
188 }
189
190no_context:
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198
199 if (fixup_exception(regs))
200 return;
201
202 die("Oops", regs, address);
203
204out_of_memory:
205 up_read(&mm->mmap_sem);
206
207 if (user_mode(regs)) {
208 pagefault_out_of_memory();
209 return;
210 }
211
212 goto no_context;
213
214do_sigbus:
215 up_read(&mm->mmap_sem);
216
217 if (!user_mode(regs))
218 goto no_context;
219
220 tsk->thread.fault_address = address;
221 info.si_signo = SIGBUS;
222 info.si_errno = 0;
223 info.si_code = BUS_ADRERR;
224 info.si_addr = (void __user *)address;
225 force_sig_info(SIGBUS, &info, tsk);
226}
227