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Commit | Line | Data |
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071327ec | 1 | /* |
1da177e4 LT |
2 | * This file is subject to the terms and conditions of the GNU General Public |
3 | * License. See the file "COPYING" in the main directory of this archive | |
4 | * for more details. | |
5 | * | |
6 | * | |
7 | * Copyright (C) 1995, 1996, 1997, 1998 by Ralf Baechle | |
8 | * Copyright 1999 SuSE GmbH (Philipp Rumpf, prumpf@tux.org) | |
9 | * Copyright 1999 Hewlett Packard Co. | |
10 | * | |
11 | */ | |
12 | ||
13 | #include <linux/mm.h> | |
14 | #include <linux/ptrace.h> | |
15 | #include <linux/sched.h> | |
16 | #include <linux/interrupt.h> | |
17 | #include <linux/module.h> | |
18 | ||
19 | #include <asm/uaccess.h> | |
20 | #include <asm/traps.h> | |
21 | ||
22 | #define PRINT_USER_FAULTS /* (turn this on if you want user faults to be */ | |
23 | /* dumped to the console via printk) */ | |
24 | ||
25 | ||
1da177e4 LT |
26 | /* Various important other fields */ |
27 | #define bit22set(x) (x & 0x00000200) | |
28 | #define bits23_25set(x) (x & 0x000001c0) | |
29 | #define isGraphicsFlushRead(x) ((x & 0xfc003fdf) == 0x04001a80) | |
30 | /* extended opcode is 0x6a */ | |
31 | ||
32 | #define BITSSET 0x1c0 /* for identifying LDCW */ | |
33 | ||
34 | ||
35 | DEFINE_PER_CPU(struct exception_data, exception_data); | |
36 | ||
37 | /* | |
38 | * parisc_acctyp(unsigned int inst) -- | |
39 | * Given a PA-RISC memory access instruction, determine if the | |
40 | * the instruction would perform a memory read or memory write | |
41 | * operation. | |
42 | * | |
43 | * This function assumes that the given instruction is a memory access | |
44 | * instruction (i.e. you should really only call it if you know that | |
45 | * the instruction has generated some sort of a memory access fault). | |
46 | * | |
47 | * Returns: | |
48 | * VM_READ if read operation | |
49 | * VM_WRITE if write operation | |
50 | * VM_EXEC if execute operation | |
51 | */ | |
52 | static unsigned long | |
53 | parisc_acctyp(unsigned long code, unsigned int inst) | |
54 | { | |
55 | if (code == 6 || code == 16) | |
56 | return VM_EXEC; | |
57 | ||
58 | switch (inst & 0xf0000000) { | |
59 | case 0x40000000: /* load */ | |
60 | case 0x50000000: /* new load */ | |
61 | return VM_READ; | |
62 | ||
63 | case 0x60000000: /* store */ | |
64 | case 0x70000000: /* new store */ | |
65 | return VM_WRITE; | |
66 | ||
67 | case 0x20000000: /* coproc */ | |
68 | case 0x30000000: /* coproc2 */ | |
69 | if (bit22set(inst)) | |
70 | return VM_WRITE; | |
71 | ||
72 | case 0x0: /* indexed/memory management */ | |
73 | if (bit22set(inst)) { | |
74 | /* | |
75 | * Check for the 'Graphics Flush Read' instruction. | |
76 | * It resembles an FDC instruction, except for bits | |
77 | * 20 and 21. Any combination other than zero will | |
78 | * utilize the block mover functionality on some | |
79 | * older PA-RISC platforms. The case where a block | |
80 | * move is performed from VM to graphics IO space | |
81 | * should be treated as a READ. | |
82 | * | |
83 | * The significance of bits 20,21 in the FDC | |
84 | * instruction is: | |
85 | * | |
86 | * 00 Flush data cache (normal instruction behavior) | |
87 | * 01 Graphics flush write (IO space -> VM) | |
88 | * 10 Graphics flush read (VM -> IO space) | |
89 | * 11 Graphics flush read/write (VM <-> IO space) | |
90 | */ | |
91 | if (isGraphicsFlushRead(inst)) | |
92 | return VM_READ; | |
93 | return VM_WRITE; | |
94 | } else { | |
95 | /* | |
96 | * Check for LDCWX and LDCWS (semaphore instructions). | |
97 | * If bits 23 through 25 are all 1's it is one of | |
98 | * the above two instructions and is a write. | |
99 | * | |
100 | * Note: With the limited bits we are looking at, | |
101 | * this will also catch PROBEW and PROBEWI. However, | |
102 | * these should never get in here because they don't | |
103 | * generate exceptions of the type: | |
104 | * Data TLB miss fault/data page fault | |
105 | * Data memory protection trap | |
106 | */ | |
107 | if (bits23_25set(inst) == BITSSET) | |
108 | return VM_WRITE; | |
109 | } | |
110 | return VM_READ; /* Default */ | |
111 | } | |
112 | return VM_READ; /* Default */ | |
113 | } | |
114 | ||
115 | #undef bit22set | |
116 | #undef bits23_25set | |
117 | #undef isGraphicsFlushRead | |
118 | #undef BITSSET | |
119 | ||
120 | ||
121 | #if 0 | |
122 | /* This is the treewalk to find a vma which is the highest that has | |
123 | * a start < addr. We're using find_vma_prev instead right now, but | |
124 | * we might want to use this at some point in the future. Probably | |
125 | * not, but I want it committed to CVS so I don't lose it :-) | |
126 | */ | |
127 | while (tree != vm_avl_empty) { | |
128 | if (tree->vm_start > addr) { | |
129 | tree = tree->vm_avl_left; | |
130 | } else { | |
131 | prev = tree; | |
132 | if (prev->vm_next == NULL) | |
133 | break; | |
134 | if (prev->vm_next->vm_start > addr) | |
135 | break; | |
136 | tree = tree->vm_avl_right; | |
137 | } | |
138 | } | |
139 | #endif | |
140 | ||
c61c25eb KM |
141 | int fixup_exception(struct pt_regs *regs) |
142 | { | |
143 | const struct exception_table_entry *fix; | |
144 | ||
61dbbaeb HD |
145 | /* If we only stored 32bit addresses in the exception table we can drop |
146 | * out if we faulted on a 64bit address. */ | |
147 | if ((sizeof(regs->iaoq[0]) > sizeof(fix->insn)) | |
148 | && (regs->iaoq[0] >> 32)) | |
149 | return 0; | |
150 | ||
c61c25eb KM |
151 | fix = search_exception_tables(regs->iaoq[0]); |
152 | if (fix) { | |
153 | struct exception_data *d; | |
154 | d = &__get_cpu_var(exception_data); | |
155 | d->fault_ip = regs->iaoq[0]; | |
156 | d->fault_space = regs->isr; | |
157 | d->fault_addr = regs->ior; | |
158 | ||
159 | regs->iaoq[0] = ((fix->fixup) & ~3); | |
160 | /* | |
161 | * NOTE: In some cases the faulting instruction | |
162 | * may be in the delay slot of a branch. We | |
163 | * don't want to take the branch, so we don't | |
164 | * increment iaoq[1], instead we set it to be | |
165 | * iaoq[0]+4, and clear the B bit in the PSW | |
166 | */ | |
167 | regs->iaoq[1] = regs->iaoq[0] + 4; | |
168 | regs->gr[0] &= ~PSW_B; /* IPSW in gr[0] */ | |
169 | ||
170 | return 1; | |
171 | } | |
172 | ||
173 | return 0; | |
174 | } | |
175 | ||
1da177e4 LT |
176 | void do_page_fault(struct pt_regs *regs, unsigned long code, |
177 | unsigned long address) | |
178 | { | |
179 | struct vm_area_struct *vma, *prev_vma; | |
2d8b22de JDA |
180 | struct task_struct *tsk; |
181 | struct mm_struct *mm; | |
1da177e4 | 182 | unsigned long acc_type; |
83c54070 | 183 | int fault; |
2d8b22de | 184 | unsigned int flags; |
1da177e4 | 185 | |
2d8b22de | 186 | if (in_atomic()) |
1da177e4 LT |
187 | goto no_context; |
188 | ||
2d8b22de JDA |
189 | tsk = current; |
190 | mm = tsk->mm; | |
191 | if (!mm) | |
192 | goto no_context; | |
193 | ||
194 | flags = FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE; | |
759496ba JW |
195 | if (user_mode(regs)) |
196 | flags |= FAULT_FLAG_USER; | |
0772dac1 FP |
197 | |
198 | acc_type = parisc_acctyp(code, regs->iir); | |
759496ba JW |
199 | if (acc_type & VM_WRITE) |
200 | flags |= FAULT_FLAG_WRITE; | |
38057477 | 201 | retry: |
1da177e4 LT |
202 | down_read(&mm->mmap_sem); |
203 | vma = find_vma_prev(mm, address, &prev_vma); | |
204 | if (!vma || address < vma->vm_start) | |
205 | goto check_expansion; | |
206 | /* | |
207 | * Ok, we have a good vm_area for this memory access. We still need to | |
208 | * check the access permissions. | |
209 | */ | |
210 | ||
211 | good_area: | |
212 | ||
1da177e4 LT |
213 | if ((vma->vm_flags & acc_type) != acc_type) |
214 | goto bad_area; | |
215 | ||
216 | /* | |
217 | * If for any reason at all we couldn't handle the fault, make | |
218 | * sure we exit gracefully rather than endlessly redo the | |
219 | * fault. | |
220 | */ | |
221 | ||
759496ba | 222 | fault = handle_mm_fault(mm, vma, address, flags); |
38057477 KC |
223 | |
224 | if ((fault & VM_FAULT_RETRY) && fatal_signal_pending(current)) | |
225 | return; | |
226 | ||
83c54070 | 227 | if (unlikely(fault & VM_FAULT_ERROR)) { |
1da177e4 | 228 | /* |
67a5a59d | 229 | * We hit a shared mapping outside of the file, or some |
6e346228 LT |
230 | * other thing happened to us that made us unable to |
231 | * handle the page fault gracefully. | |
1da177e4 | 232 | */ |
83c54070 NP |
233 | if (fault & VM_FAULT_OOM) |
234 | goto out_of_memory; | |
235 | else if (fault & VM_FAULT_SIGBUS) | |
236 | goto bad_area; | |
237 | BUG(); | |
1da177e4 | 238 | } |
38057477 KC |
239 | if (flags & FAULT_FLAG_ALLOW_RETRY) { |
240 | if (fault & VM_FAULT_MAJOR) | |
241 | current->maj_flt++; | |
242 | else | |
243 | current->min_flt++; | |
244 | if (fault & VM_FAULT_RETRY) { | |
245 | flags &= ~FAULT_FLAG_ALLOW_RETRY; | |
246 | ||
247 | /* | |
248 | * No need to up_read(&mm->mmap_sem) as we would | |
249 | * have already released it in __lock_page_or_retry | |
250 | * in mm/filemap.c. | |
251 | */ | |
252 | ||
253 | goto retry; | |
254 | } | |
255 | } | |
1da177e4 LT |
256 | up_read(&mm->mmap_sem); |
257 | return; | |
258 | ||
259 | check_expansion: | |
260 | vma = prev_vma; | |
261 | if (vma && (expand_stack(vma, address) == 0)) | |
262 | goto good_area; | |
263 | ||
264 | /* | |
265 | * Something tried to access memory that isn't in our memory map.. | |
266 | */ | |
267 | bad_area: | |
268 | up_read(&mm->mmap_sem); | |
269 | ||
270 | if (user_mode(regs)) { | |
271 | struct siginfo si; | |
272 | ||
273 | #ifdef PRINT_USER_FAULTS | |
274 | printk(KERN_DEBUG "\n"); | |
275 | printk(KERN_DEBUG "do_page_fault() pid=%d command='%s' type=%lu address=0x%08lx\n", | |
19c5870c | 276 | task_pid_nr(tsk), tsk->comm, code, address); |
1da177e4 LT |
277 | if (vma) { |
278 | printk(KERN_DEBUG "vm_start = 0x%08lx, vm_end = 0x%08lx\n", | |
279 | vma->vm_start, vma->vm_end); | |
280 | } | |
281 | show_regs(regs); | |
282 | #endif | |
283 | /* FIXME: actually we need to get the signo and code correct */ | |
284 | si.si_signo = SIGSEGV; | |
285 | si.si_errno = 0; | |
286 | si.si_code = SEGV_MAPERR; | |
287 | si.si_addr = (void __user *) address; | |
288 | force_sig_info(SIGSEGV, &si, current); | |
289 | return; | |
290 | } | |
291 | ||
292 | no_context: | |
293 | ||
c61c25eb KM |
294 | if (!user_mode(regs) && fixup_exception(regs)) { |
295 | return; | |
1da177e4 LT |
296 | } |
297 | ||
298 | parisc_terminate("Bad Address (null pointer deref?)", regs, code, address); | |
299 | ||
300 | out_of_memory: | |
301 | up_read(&mm->mmap_sem); | |
53e30d02 NP |
302 | if (!user_mode(regs)) |
303 | goto no_context; | |
304 | pagefault_out_of_memory(); | |
1da177e4 | 305 | } |