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8#include <linux/sched/signal.h>
9#include <linux/kernel.h>
10#include <linux/mm.h>
11#include <linux/extable.h>
12#include <linux/interrupt.h>
13#include <linux/kprobes.h>
14#include <linux/kdebug.h>
15#include <linux/prefetch.h>
16#include <linux/uaccess.h>
17
18#include <asm/pgtable.h>
19#include <asm/processor.h>
20#include <asm/exception.h>
21
22extern int die(char *, struct pt_regs *, long);
23
24#ifdef CONFIG_KPROBES
25static inline int notify_page_fault(struct pt_regs *regs, int trap)
26{
27 int ret = 0;
28
29 if (!user_mode(regs)) {
30
31 preempt_disable();
32 if (kprobe_running() && kprobe_fault_handler(regs, trap))
33 ret = 1;
34 preempt_enable();
35 }
36
37 return ret;
38}
39#else
40static inline int notify_page_fault(struct pt_regs *regs, int trap)
41{
42 return 0;
43}
44#endif
45
46
47
48
49
50static int
51mapped_kernel_page_is_present (unsigned long address)
52{
53 pgd_t *pgd;
54 pud_t *pud;
55 pmd_t *pmd;
56 pte_t *ptep, pte;
57
58 pgd = pgd_offset_k(address);
59 if (pgd_none(*pgd) || pgd_bad(*pgd))
60 return 0;
61
62 pud = pud_offset(pgd, address);
63 if (pud_none(*pud) || pud_bad(*pud))
64 return 0;
65
66 pmd = pmd_offset(pud, address);
67 if (pmd_none(*pmd) || pmd_bad(*pmd))
68 return 0;
69
70 ptep = pte_offset_kernel(pmd, address);
71 if (!ptep)
72 return 0;
73
74 pte = *ptep;
75 return pte_present(pte);
76}
77
78# define VM_READ_BIT 0
79# define VM_WRITE_BIT 1
80# define VM_EXEC_BIT 2
81
82void __kprobes
83ia64_do_page_fault (unsigned long address, unsigned long isr, struct pt_regs *regs)
84{
85 int signal = SIGSEGV, code = SEGV_MAPERR;
86 struct vm_area_struct *vma, *prev_vma;
87 struct mm_struct *mm = current->mm;
88 unsigned long mask;
89 vm_fault_t fault;
90 unsigned int flags = FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE;
91
92 mask = ((((isr >> IA64_ISR_X_BIT) & 1UL) << VM_EXEC_BIT)
93 | (((isr >> IA64_ISR_W_BIT) & 1UL) << VM_WRITE_BIT));
94
95
96 prefetchw(&mm->mmap_sem);
97
98
99
100
101 if (faulthandler_disabled() || !mm)
102 goto no_context;
103
104#ifdef CONFIG_VIRTUAL_MEM_MAP
105
106
107
108
109
110
111
112 if ((REGION_NUMBER(address) == 5) && !user_mode(regs))
113 goto bad_area_no_up;
114#endif
115
116
117
118
119 if (notify_page_fault(regs, TRAP_BRKPT))
120 return;
121
122 if (user_mode(regs))
123 flags |= FAULT_FLAG_USER;
124 if (mask & VM_WRITE)
125 flags |= FAULT_FLAG_WRITE;
126retry:
127 down_read(&mm->mmap_sem);
128
129 vma = find_vma_prev(mm, address, &prev_vma);
130 if (!vma && !prev_vma )
131 goto bad_area;
132
133
134
135
136
137
138
139
140 if (( !vma && prev_vma ) || (address < vma->vm_start) )
141 goto check_expansion;
142
143 good_area:
144 code = SEGV_ACCERR;
145
146
147
148# if (((1 << VM_READ_BIT) != VM_READ || (1 << VM_WRITE_BIT) != VM_WRITE) \
149 || (1 << VM_EXEC_BIT) != VM_EXEC)
150# error File is out of sync with <linux/mm.h>. Please update.
151# endif
152
153 if (((isr >> IA64_ISR_R_BIT) & 1UL) && (!(vma->vm_flags & (VM_READ | VM_WRITE))))
154 goto bad_area;
155
156 if ((vma->vm_flags & mask) != mask)
157 goto bad_area;
158
159
160
161
162
163
164 fault = handle_mm_fault(vma, address, flags);
165
166 if ((fault & VM_FAULT_RETRY) && fatal_signal_pending(current))
167 return;
168
169 if (unlikely(fault & VM_FAULT_ERROR)) {
170
171
172
173
174
175 if (fault & VM_FAULT_OOM) {
176 goto out_of_memory;
177 } else if (fault & VM_FAULT_SIGSEGV) {
178 goto bad_area;
179 } else if (fault & VM_FAULT_SIGBUS) {
180 signal = SIGBUS;
181 goto bad_area;
182 }
183 BUG();
184 }
185
186 if (flags & FAULT_FLAG_ALLOW_RETRY) {
187 if (fault & VM_FAULT_MAJOR)
188 current->maj_flt++;
189 else
190 current->min_flt++;
191 if (fault & VM_FAULT_RETRY) {
192 flags &= ~FAULT_FLAG_ALLOW_RETRY;
193 flags |= FAULT_FLAG_TRIED;
194
195
196
197
198
199
200 goto retry;
201 }
202 }
203
204 up_read(&mm->mmap_sem);
205 return;
206
207 check_expansion:
208 if (!(prev_vma && (prev_vma->vm_flags & VM_GROWSUP) && (address == prev_vma->vm_end))) {
209 if (!vma)
210 goto bad_area;
211 if (!(vma->vm_flags & VM_GROWSDOWN))
212 goto bad_area;
213 if (REGION_NUMBER(address) != REGION_NUMBER(vma->vm_start)
214 || REGION_OFFSET(address) >= RGN_MAP_LIMIT)
215 goto bad_area;
216 if (expand_stack(vma, address))
217 goto bad_area;
218 } else {
219 vma = prev_vma;
220 if (REGION_NUMBER(address) != REGION_NUMBER(vma->vm_start)
221 || REGION_OFFSET(address) >= RGN_MAP_LIMIT)
222 goto bad_area;
223
224
225
226
227 if (address > vma->vm_end + PAGE_SIZE - sizeof(long))
228 goto bad_area;
229 if (expand_upwards(vma, address))
230 goto bad_area;
231 }
232 goto good_area;
233
234 bad_area:
235 up_read(&mm->mmap_sem);
236#ifdef CONFIG_VIRTUAL_MEM_MAP
237 bad_area_no_up:
238#endif
239 if ((isr & IA64_ISR_SP)
240 || ((isr & IA64_ISR_NA) && (isr & IA64_ISR_CODE_MASK) == IA64_ISR_CODE_LFETCH))
241 {
242
243
244
245
246
247 ia64_psr(regs)->ed = 1;
248 return;
249 }
250 if (user_mode(regs)) {
251 force_sig_fault(signal, code, (void __user *) address,
252 0, __ISR_VALID, isr, current);
253 return;
254 }
255
256 no_context:
257 if ((isr & IA64_ISR_SP)
258 || ((isr & IA64_ISR_NA) && (isr & IA64_ISR_CODE_MASK) == IA64_ISR_CODE_LFETCH))
259 {
260
261
262
263
264
265 ia64_psr(regs)->ed = 1;
266 return;
267 }
268
269
270
271
272
273
274
275
276 if (REGION_NUMBER(address) == 5 && mapped_kernel_page_is_present(address))
277 return;
278
279 if (ia64_done_with_exception(regs))
280 return;
281
282
283
284
285
286 bust_spinlocks(1);
287
288 if (address < PAGE_SIZE)
289 printk(KERN_ALERT "Unable to handle kernel NULL pointer dereference (address %016lx)\n", address);
290 else
291 printk(KERN_ALERT "Unable to handle kernel paging request at "
292 "virtual address %016lx\n", address);
293 if (die("Oops", regs, isr))
294 regs = NULL;
295 bust_spinlocks(0);
296 if (regs)
297 do_exit(SIGKILL);
298 return;
299
300 out_of_memory:
301 up_read(&mm->mmap_sem);
302 if (!user_mode(regs))
303 goto no_context;
304 pagefault_out_of_memory();
305}
306