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8#include <linux/signal.h>
9#include <linux/sched.h>
10#include <linux/interrupt.h>
11#include <linux/kernel.h>
12#include <linux/errno.h>
13#include <linux/string.h>
14#include <linux/types.h>
15#include <linux/ptrace.h>
16#include <linux/mman.h>
17#include <linux/mm.h>
18#include <linux/smp.h>
19#include <linux/module.h>
20#include <linux/kprobes.h>
21#include <linux/perf_event.h>
22
23#include <asm/branch.h>
24#include <asm/mmu_context.h>
25#include <asm/system.h>
26#include <asm/uaccess.h>
27#include <asm/ptrace.h>
28#include <asm/highmem.h>
29#include <linux/kdebug.h>
30
31
32
33
34
35
36asmlinkage void __kprobes do_page_fault(struct pt_regs *regs, unsigned long write,
37 unsigned long address)
38{
39 struct vm_area_struct * vma = NULL;
40 struct task_struct *tsk = current;
41 struct mm_struct *mm = tsk->mm;
42 const int field = sizeof(unsigned long) * 2;
43 siginfo_t info;
44 int fault;
45
46#if 0
47 printk("Cpu%d[%s:%d:%0*lx:%ld:%0*lx]\n", raw_smp_processor_id(),
48 current->comm, current->pid, field, address, write,
49 field, regs->cp0_epc);
50#endif
51
52#ifdef CONFIG_KPROBES
53
54
55
56
57
58 if (notify_die(DIE_PAGE_FAULT, "page fault", regs, -1,
59 (regs->cp0_cause >> 2) & 0x1f, SIGSEGV) == NOTIFY_STOP)
60 return;
61#endif
62
63 info.si_code = SEGV_MAPERR;
64
65
66
67
68
69
70
71
72
73
74#ifdef CONFIG_64BIT
75# define VMALLOC_FAULT_TARGET no_context
76#else
77# define VMALLOC_FAULT_TARGET vmalloc_fault
78#endif
79
80 if (unlikely(address >= VMALLOC_START && address <= VMALLOC_END))
81 goto VMALLOC_FAULT_TARGET;
82#ifdef MODULE_START
83 if (unlikely(address >= MODULE_START && address < MODULE_END))
84 goto VMALLOC_FAULT_TARGET;
85#endif
86
87
88
89
90
91 if (in_atomic() || !mm)
92 goto bad_area_nosemaphore;
93
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
105
106
107
108good_area:
109 info.si_code = SEGV_ACCERR;
110
111 if (write) {
112 if (!(vma->vm_flags & VM_WRITE))
113 goto bad_area;
114 } else {
115 if (kernel_uses_smartmips_rixi) {
116 if (address == regs->cp0_epc && !(vma->vm_flags & VM_EXEC)) {
117#if 0
118 pr_notice("Cpu%d[%s:%d:%0*lx:%ld:%0*lx] XI violation\n",
119 raw_smp_processor_id(),
120 current->comm, current->pid,
121 field, address, write,
122 field, regs->cp0_epc);
123#endif
124 goto bad_area;
125 }
126 if (!(vma->vm_flags & VM_READ)) {
127#if 0
128 pr_notice("Cpu%d[%s:%d:%0*lx:%ld:%0*lx] RI violation\n",
129 raw_smp_processor_id(),
130 current->comm, current->pid,
131 field, address, write,
132 field, regs->cp0_epc);
133#endif
134 goto bad_area;
135 }
136 } else {
137 if (!(vma->vm_flags & (VM_READ | VM_WRITE | VM_EXEC)))
138 goto bad_area;
139 }
140 }
141
142
143
144
145
146
147 fault = handle_mm_fault(mm, vma, address, write ? FAULT_FLAG_WRITE : 0);
148 perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS, 1, 0, regs, address);
149 if (unlikely(fault & VM_FAULT_ERROR)) {
150 if (fault & VM_FAULT_OOM)
151 goto out_of_memory;
152 else if (fault & VM_FAULT_SIGBUS)
153 goto do_sigbus;
154 BUG();
155 }
156 if (fault & VM_FAULT_MAJOR) {
157 perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MAJ,
158 1, 0, regs, address);
159 tsk->maj_flt++;
160 } else {
161 perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MIN,
162 1, 0, regs, address);
163 tsk->min_flt++;
164 }
165
166 up_read(&mm->mmap_sem);
167 return;
168
169
170
171
172
173bad_area:
174 up_read(&mm->mmap_sem);
175
176bad_area_nosemaphore:
177
178 if (user_mode(regs)) {
179 tsk->thread.cp0_badvaddr = address;
180 tsk->thread.error_code = write;
181#if 0
182 printk("do_page_fault() #2: sending SIGSEGV to %s for "
183 "invalid %s\n%0*lx (epc == %0*lx, ra == %0*lx)\n",
184 tsk->comm,
185 write ? "write access to" : "read access from",
186 field, address,
187 field, (unsigned long) regs->cp0_epc,
188 field, (unsigned long) regs->regs[31]);
189#endif
190 info.si_signo = SIGSEGV;
191 info.si_errno = 0;
192
193 info.si_addr = (void __user *) address;
194 force_sig_info(SIGSEGV, &info, tsk);
195 return;
196 }
197
198no_context:
199
200 if (fixup_exception(regs)) {
201 current->thread.cp0_baduaddr = address;
202 return;
203 }
204
205
206
207
208
209 bust_spinlocks(1);
210
211 printk(KERN_ALERT "CPU %d Unable to handle kernel paging request at "
212 "virtual address %0*lx, epc == %0*lx, ra == %0*lx\n",
213 raw_smp_processor_id(), field, address, field, regs->cp0_epc,
214 field, regs->regs[31]);
215 die("Oops", regs);
216
217out_of_memory:
218
219
220
221
222 up_read(&mm->mmap_sem);
223 pagefault_out_of_memory();
224 return;
225
226do_sigbus:
227 up_read(&mm->mmap_sem);
228
229
230 if (!user_mode(regs))
231 goto no_context;
232 else
233
234
235
236
237#if 0
238 printk("do_page_fault() #3: sending SIGBUS to %s for "
239 "invalid %s\n%0*lx (epc == %0*lx, ra == %0*lx)\n",
240 tsk->comm,
241 write ? "write access to" : "read access from",
242 field, address,
243 field, (unsigned long) regs->cp0_epc,
244 field, (unsigned long) regs->regs[31]);
245#endif
246 tsk->thread.cp0_badvaddr = address;
247 info.si_signo = SIGBUS;
248 info.si_errno = 0;
249 info.si_code = BUS_ADRERR;
250 info.si_addr = (void __user *) address;
251 force_sig_info(SIGBUS, &info, tsk);
252
253 return;
254#ifndef CONFIG_64BIT
255vmalloc_fault:
256 {
257
258
259
260
261
262
263
264 int offset = __pgd_offset(address);
265 pgd_t *pgd, *pgd_k;
266 pud_t *pud, *pud_k;
267 pmd_t *pmd, *pmd_k;
268 pte_t *pte_k;
269
270 pgd = (pgd_t *) pgd_current[raw_smp_processor_id()] + offset;
271 pgd_k = init_mm.pgd + offset;
272
273 if (!pgd_present(*pgd_k))
274 goto no_context;
275 set_pgd(pgd, *pgd_k);
276
277 pud = pud_offset(pgd, address);
278 pud_k = pud_offset(pgd_k, address);
279 if (!pud_present(*pud_k))
280 goto no_context;
281
282 pmd = pmd_offset(pud, address);
283 pmd_k = pmd_offset(pud_k, address);
284 if (!pmd_present(*pmd_k))
285 goto no_context;
286 set_pmd(pmd, *pmd_k);
287
288 pte_k = pte_offset_kernel(pmd_k, address);
289 if (!pte_present(*pte_k))
290 goto no_context;
291 return;
292 }
293#endif
294}
295