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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> | |
70ffdb93 | 18 | #include <linux/uaccess.h> |
1da177e4 | 19 | |
1da177e4 LT |
20 | #include <asm/traps.h> |
21 | ||
1da177e4 LT |
22 | /* Various important other fields */ |
23 | #define bit22set(x) (x & 0x00000200) | |
24 | #define bits23_25set(x) (x & 0x000001c0) | |
25 | #define isGraphicsFlushRead(x) ((x & 0xfc003fdf) == 0x04001a80) | |
26 | /* extended opcode is 0x6a */ | |
27 | ||
28 | #define BITSSET 0x1c0 /* for identifying LDCW */ | |
29 | ||
30 | ||
31 | DEFINE_PER_CPU(struct exception_data, exception_data); | |
32 | ||
fef47e2a HD |
33 | int show_unhandled_signals = 1; |
34 | ||
1da177e4 LT |
35 | /* |
36 | * parisc_acctyp(unsigned int inst) -- | |
37 | * Given a PA-RISC memory access instruction, determine if the | |
38 | * the instruction would perform a memory read or memory write | |
39 | * operation. | |
40 | * | |
41 | * This function assumes that the given instruction is a memory access | |
42 | * instruction (i.e. you should really only call it if you know that | |
43 | * the instruction has generated some sort of a memory access fault). | |
44 | * | |
45 | * Returns: | |
46 | * VM_READ if read operation | |
47 | * VM_WRITE if write operation | |
48 | * VM_EXEC if execute operation | |
49 | */ | |
50 | static unsigned long | |
51 | parisc_acctyp(unsigned long code, unsigned int inst) | |
52 | { | |
53 | if (code == 6 || code == 16) | |
54 | return VM_EXEC; | |
55 | ||
56 | switch (inst & 0xf0000000) { | |
57 | case 0x40000000: /* load */ | |
58 | case 0x50000000: /* new load */ | |
59 | return VM_READ; | |
60 | ||
61 | case 0x60000000: /* store */ | |
62 | case 0x70000000: /* new store */ | |
63 | return VM_WRITE; | |
64 | ||
65 | case 0x20000000: /* coproc */ | |
66 | case 0x30000000: /* coproc2 */ | |
67 | if (bit22set(inst)) | |
68 | return VM_WRITE; | |
69 | ||
70 | case 0x0: /* indexed/memory management */ | |
71 | if (bit22set(inst)) { | |
72 | /* | |
73 | * Check for the 'Graphics Flush Read' instruction. | |
74 | * It resembles an FDC instruction, except for bits | |
75 | * 20 and 21. Any combination other than zero will | |
76 | * utilize the block mover functionality on some | |
77 | * older PA-RISC platforms. The case where a block | |
78 | * move is performed from VM to graphics IO space | |
79 | * should be treated as a READ. | |
80 | * | |
81 | * The significance of bits 20,21 in the FDC | |
82 | * instruction is: | |
83 | * | |
84 | * 00 Flush data cache (normal instruction behavior) | |
85 | * 01 Graphics flush write (IO space -> VM) | |
86 | * 10 Graphics flush read (VM -> IO space) | |
87 | * 11 Graphics flush read/write (VM <-> IO space) | |
88 | */ | |
89 | if (isGraphicsFlushRead(inst)) | |
90 | return VM_READ; | |
91 | return VM_WRITE; | |
92 | } else { | |
93 | /* | |
94 | * Check for LDCWX and LDCWS (semaphore instructions). | |
95 | * If bits 23 through 25 are all 1's it is one of | |
96 | * the above two instructions and is a write. | |
97 | * | |
98 | * Note: With the limited bits we are looking at, | |
99 | * this will also catch PROBEW and PROBEWI. However, | |
100 | * these should never get in here because they don't | |
101 | * generate exceptions of the type: | |
102 | * Data TLB miss fault/data page fault | |
103 | * Data memory protection trap | |
104 | */ | |
105 | if (bits23_25set(inst) == BITSSET) | |
106 | return VM_WRITE; | |
107 | } | |
108 | return VM_READ; /* Default */ | |
109 | } | |
110 | return VM_READ; /* Default */ | |
111 | } | |
112 | ||
113 | #undef bit22set | |
114 | #undef bits23_25set | |
115 | #undef isGraphicsFlushRead | |
116 | #undef BITSSET | |
117 | ||
118 | ||
119 | #if 0 | |
120 | /* This is the treewalk to find a vma which is the highest that has | |
121 | * a start < addr. We're using find_vma_prev instead right now, but | |
122 | * we might want to use this at some point in the future. Probably | |
123 | * not, but I want it committed to CVS so I don't lose it :-) | |
124 | */ | |
125 | while (tree != vm_avl_empty) { | |
126 | if (tree->vm_start > addr) { | |
127 | tree = tree->vm_avl_left; | |
128 | } else { | |
129 | prev = tree; | |
130 | if (prev->vm_next == NULL) | |
131 | break; | |
132 | if (prev->vm_next->vm_start > addr) | |
133 | break; | |
134 | tree = tree->vm_avl_right; | |
135 | } | |
136 | } | |
137 | #endif | |
138 | ||
c61c25eb KM |
139 | int fixup_exception(struct pt_regs *regs) |
140 | { | |
141 | const struct exception_table_entry *fix; | |
142 | ||
61dbbaeb HD |
143 | /* If we only stored 32bit addresses in the exception table we can drop |
144 | * out if we faulted on a 64bit address. */ | |
145 | if ((sizeof(regs->iaoq[0]) > sizeof(fix->insn)) | |
146 | && (regs->iaoq[0] >> 32)) | |
147 | return 0; | |
148 | ||
c61c25eb KM |
149 | fix = search_exception_tables(regs->iaoq[0]); |
150 | if (fix) { | |
151 | struct exception_data *d; | |
496252f7 | 152 | d = this_cpu_ptr(&exception_data); |
c61c25eb KM |
153 | d->fault_ip = regs->iaoq[0]; |
154 | d->fault_space = regs->isr; | |
155 | d->fault_addr = regs->ior; | |
156 | ||
157 | regs->iaoq[0] = ((fix->fixup) & ~3); | |
158 | /* | |
159 | * NOTE: In some cases the faulting instruction | |
160 | * may be in the delay slot of a branch. We | |
161 | * don't want to take the branch, so we don't | |
162 | * increment iaoq[1], instead we set it to be | |
163 | * iaoq[0]+4, and clear the B bit in the PSW | |
164 | */ | |
165 | regs->iaoq[1] = regs->iaoq[0] + 4; | |
166 | regs->gr[0] &= ~PSW_B; /* IPSW in gr[0] */ | |
167 | ||
168 | return 1; | |
169 | } | |
170 | ||
171 | return 0; | |
172 | } | |
173 | ||
fef47e2a HD |
174 | /* |
175 | * Print out info about fatal segfaults, if the show_unhandled_signals | |
176 | * sysctl is set: | |
177 | */ | |
178 | static inline void | |
179 | show_signal_msg(struct pt_regs *regs, unsigned long code, | |
180 | unsigned long address, struct task_struct *tsk, | |
181 | struct vm_area_struct *vma) | |
182 | { | |
183 | if (!unhandled_signal(tsk, SIGSEGV)) | |
184 | return; | |
185 | ||
186 | if (!printk_ratelimit()) | |
187 | return; | |
188 | ||
189 | pr_warn("\n"); | |
190 | pr_warn("do_page_fault() command='%s' type=%lu address=0x%08lx", | |
191 | tsk->comm, code, address); | |
192 | print_vma_addr(KERN_CONT " in ", regs->iaoq[0]); | |
193 | if (vma) | |
194 | pr_warn(" vm_start = 0x%08lx, vm_end = 0x%08lx\n", | |
195 | vma->vm_start, vma->vm_end); | |
196 | ||
197 | show_regs(regs); | |
198 | } | |
199 | ||
1da177e4 LT |
200 | void do_page_fault(struct pt_regs *regs, unsigned long code, |
201 | unsigned long address) | |
202 | { | |
203 | struct vm_area_struct *vma, *prev_vma; | |
2d8b22de JDA |
204 | struct task_struct *tsk; |
205 | struct mm_struct *mm; | |
1da177e4 | 206 | unsigned long acc_type; |
83c54070 | 207 | int fault; |
2d8b22de | 208 | unsigned int flags; |
1da177e4 | 209 | |
70ffdb93 | 210 | if (pagefault_disabled()) |
1da177e4 LT |
211 | goto no_context; |
212 | ||
2d8b22de JDA |
213 | tsk = current; |
214 | mm = tsk->mm; | |
215 | if (!mm) | |
216 | goto no_context; | |
217 | ||
218 | flags = FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE; | |
759496ba JW |
219 | if (user_mode(regs)) |
220 | flags |= FAULT_FLAG_USER; | |
0772dac1 FP |
221 | |
222 | acc_type = parisc_acctyp(code, regs->iir); | |
759496ba JW |
223 | if (acc_type & VM_WRITE) |
224 | flags |= FAULT_FLAG_WRITE; | |
38057477 | 225 | retry: |
1da177e4 LT |
226 | down_read(&mm->mmap_sem); |
227 | vma = find_vma_prev(mm, address, &prev_vma); | |
228 | if (!vma || address < vma->vm_start) | |
229 | goto check_expansion; | |
230 | /* | |
231 | * Ok, we have a good vm_area for this memory access. We still need to | |
232 | * check the access permissions. | |
233 | */ | |
234 | ||
235 | good_area: | |
236 | ||
1da177e4 LT |
237 | if ((vma->vm_flags & acc_type) != acc_type) |
238 | goto bad_area; | |
239 | ||
240 | /* | |
241 | * If for any reason at all we couldn't handle the fault, make | |
242 | * sure we exit gracefully rather than endlessly redo the | |
243 | * fault. | |
244 | */ | |
245 | ||
759496ba | 246 | fault = handle_mm_fault(mm, vma, address, flags); |
38057477 KC |
247 | |
248 | if ((fault & VM_FAULT_RETRY) && fatal_signal_pending(current)) | |
249 | return; | |
250 | ||
83c54070 | 251 | if (unlikely(fault & VM_FAULT_ERROR)) { |
1da177e4 | 252 | /* |
67a5a59d | 253 | * We hit a shared mapping outside of the file, or some |
6e346228 LT |
254 | * other thing happened to us that made us unable to |
255 | * handle the page fault gracefully. | |
1da177e4 | 256 | */ |
83c54070 NP |
257 | if (fault & VM_FAULT_OOM) |
258 | goto out_of_memory; | |
33692f27 LT |
259 | else if (fault & VM_FAULT_SIGSEGV) |
260 | goto bad_area; | |
83c54070 NP |
261 | else if (fault & VM_FAULT_SIGBUS) |
262 | goto bad_area; | |
263 | BUG(); | |
1da177e4 | 264 | } |
38057477 KC |
265 | if (flags & FAULT_FLAG_ALLOW_RETRY) { |
266 | if (fault & VM_FAULT_MAJOR) | |
267 | current->maj_flt++; | |
268 | else | |
269 | current->min_flt++; | |
270 | if (fault & VM_FAULT_RETRY) { | |
271 | flags &= ~FAULT_FLAG_ALLOW_RETRY; | |
272 | ||
273 | /* | |
274 | * No need to up_read(&mm->mmap_sem) as we would | |
275 | * have already released it in __lock_page_or_retry | |
276 | * in mm/filemap.c. | |
277 | */ | |
278 | ||
279 | goto retry; | |
280 | } | |
281 | } | |
1da177e4 LT |
282 | up_read(&mm->mmap_sem); |
283 | return; | |
284 | ||
285 | check_expansion: | |
286 | vma = prev_vma; | |
287 | if (vma && (expand_stack(vma, address) == 0)) | |
288 | goto good_area; | |
289 | ||
290 | /* | |
291 | * Something tried to access memory that isn't in our memory map.. | |
292 | */ | |
293 | bad_area: | |
294 | up_read(&mm->mmap_sem); | |
295 | ||
296 | if (user_mode(regs)) { | |
297 | struct siginfo si; | |
298 | ||
fef47e2a HD |
299 | show_signal_msg(regs, code, address, tsk, vma); |
300 | ||
1f2048fd HD |
301 | switch (code) { |
302 | case 15: /* Data TLB miss fault/Data page fault */ | |
49d1cb2b HD |
303 | /* send SIGSEGV when outside of vma */ |
304 | if (!vma || | |
305 | address < vma->vm_start || address > vma->vm_end) { | |
306 | si.si_signo = SIGSEGV; | |
307 | si.si_code = SEGV_MAPERR; | |
308 | break; | |
309 | } | |
310 | ||
311 | /* send SIGSEGV for wrong permissions */ | |
312 | if ((vma->vm_flags & acc_type) != acc_type) { | |
313 | si.si_signo = SIGSEGV; | |
314 | si.si_code = SEGV_ACCERR; | |
315 | break; | |
316 | } | |
317 | ||
318 | /* probably address is outside of mapped file */ | |
319 | /* fall through */ | |
1f2048fd HD |
320 | case 17: /* NA data TLB miss / page fault */ |
321 | case 18: /* Unaligned access - PCXS only */ | |
322 | si.si_signo = SIGBUS; | |
49d1cb2b | 323 | si.si_code = (code == 18) ? BUS_ADRALN : BUS_ADRERR; |
1f2048fd HD |
324 | break; |
325 | case 16: /* Non-access instruction TLB miss fault */ | |
326 | case 26: /* PCXL: Data memory access rights trap */ | |
327 | default: | |
328 | si.si_signo = SIGSEGV; | |
49d1cb2b HD |
329 | si.si_code = (code == 26) ? SEGV_ACCERR : SEGV_MAPERR; |
330 | break; | |
1f2048fd | 331 | } |
1da177e4 | 332 | si.si_errno = 0; |
1da177e4 | 333 | si.si_addr = (void __user *) address; |
1f2048fd | 334 | force_sig_info(si.si_signo, &si, current); |
1da177e4 LT |
335 | return; |
336 | } | |
337 | ||
338 | no_context: | |
339 | ||
c61c25eb KM |
340 | if (!user_mode(regs) && fixup_exception(regs)) { |
341 | return; | |
1da177e4 LT |
342 | } |
343 | ||
344 | parisc_terminate("Bad Address (null pointer deref?)", regs, code, address); | |
345 | ||
346 | out_of_memory: | |
347 | up_read(&mm->mmap_sem); | |
53e30d02 NP |
348 | if (!user_mode(regs)) |
349 | goto no_context; | |
350 | pagefault_out_of_memory(); | |
1da177e4 | 351 | } |