1 /*
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/sched/debug.h>
17 #include <linux/interrupt.h>
18 #include <linux/extable.h>
19 #include <linux/uaccess.h>
20 #include <linux/hugetlb.h>
21
22 #include <asm/traps.h>
23
24 /* Various important other fields */
25 #define bit22set(x) (x & 0x00000200)
26 #define bits23_25set(x) (x & 0x000001c0)
27 #define isGraphicsFlushRead(x) ((x & 0xfc003fdf) == 0x04001a80)
28 /* extended opcode is 0x6a */
29
30 #define BITSSET 0x1c0 /* for identifying LDCW */
31
32
33 int show_unhandled_signals = 1;
34
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 /* fall through */
70
71 case 0x0: /* indexed/memory management */
72 if (bit22set(inst)) {
73 /*
74 * Check for the 'Graphics Flush Read' instruction.
75 * It resembles an FDC instruction, except for bits
76 * 20 and 21. Any combination other than zero will
77 * utilize the block mover functionality on some
78 * older PA-RISC platforms. The case where a block
79 * move is performed from VM to graphics IO space
80 * should be treated as a READ.
81 *
82 * The significance of bits 20,21 in the FDC
83 * instruction is:
84 *
85 * 00 Flush data cache (normal instruction behavior)
86 * 01 Graphics flush write (IO space -> VM)
87 * 10 Graphics flush read (VM -> IO space)
88 * 11 Graphics flush read/write (VM <-> IO space)
89 */
90 if (isGraphicsFlushRead(inst))
91 return VM_READ;
92 return VM_WRITE;
93 } else {
94 /*
95 * Check for LDCWX and LDCWS (semaphore instructions).
96 * If bits 23 through 25 are all 1's it is one of
97 * the above two instructions and is a write.
98 *
99 * Note: With the limited bits we are looking at,
100 * this will also catch PROBEW and PROBEWI. However,
101 * these should never get in here because they don't
102 * generate exceptions of the type:
103 * Data TLB miss fault/data page fault
104 * Data memory protection trap
105 */
106 if (bits23_25set(inst) == BITSSET)
107 return VM_WRITE;
108 }
109 return VM_READ; /* Default */
110 }
111 return VM_READ; /* Default */
112 }
113
114 #undef bit22set
115 #undef bits23_25set
116 #undef isGraphicsFlushRead
117 #undef BITSSET
118
119
120 #if 0
121 /* This is the treewalk to find a vma which is the highest that has
122 * a start < addr. We're using find_vma_prev instead right now, but
123 * we might want to use this at some point in the future. Probably
124 * not, but I want it committed to CVS so I don't lose it :-)
125 */
126 while (tree != vm_avl_empty) {
127 if (tree->vm_start > addr) {
128 tree = tree->vm_avl_left;
129 } else {
130 prev = tree;
131 if (prev->vm_next == NULL)
132 break;
133 if (prev->vm_next->vm_start > addr)
134 break;
135 tree = tree->vm_avl_right;
136 }
137 }
138 #endif
139
140 int fixup_exception(struct pt_regs *regs)
141 {
142 const struct exception_table_entry *fix;
143
144 fix = search_exception_tables(regs->iaoq[0]);
145 if (fix) {
146 /*
147 * Fix up get_user() and put_user().
148 * ASM_EXCEPTIONTABLE_ENTRY_EFAULT() sets the least-significant
149 * bit in the relative address of the fixup routine to indicate
150 * that %r8 should be loaded with -EFAULT to report a userspace
151 * access error.
152 */
153 if (fix->fixup & 1) {
154 regs->gr[8] = -EFAULT;
155
156 /* zero target register for get_user() */
157 if (parisc_acctyp(0, regs->iir) == VM_READ) {
158 int treg = regs->iir & 0x1f;
159 BUG_ON(treg == 0);
160 regs->gr[treg] = 0;
161 }
162 }
163
164 regs->iaoq[0] = (unsigned long)&fix->fixup + fix->fixup;
165 regs->iaoq[0] &= ~3;
166 /*
167 * NOTE: In some cases the faulting instruction
168 * may be in the delay slot of a branch. We
169 * don't want to take the branch, so we don't
170 * increment iaoq[1], instead we set it to be
171 * iaoq[0]+4, and clear the B bit in the PSW
172 */
173 regs->iaoq[1] = regs->iaoq[0] + 4;
174 regs->gr[0] &= ~PSW_B; /* IPSW in gr[0] */
175
176 return 1;
177 }
178
179 return 0;
180 }
181
182 /*
183 * parisc hardware trap list
184 *
185 * Documented in section 3 "Addressing and Access Control" of the
186 * "PA-RISC 1.1 Architecture and Instruction Set Reference Manual"
187 * https://parisc.wiki.kernel.org/index.php/File:Pa11_acd.pdf
188 *
189 * For implementation see handle_interruption() in traps.c
190 */
191 static const char * const trap_description[] = {
192 [1] "High-priority machine check (HPMC)",
193 [2] "Power failure interrupt",
194 [3] "Recovery counter trap",
195 [5] "Low-priority machine check",
196 [6] "Instruction TLB miss fault",
197 [7] "Instruction access rights / protection trap",
198 [8] "Illegal instruction trap",
199 [9] "Break instruction trap",
200 [10] "Privileged operation trap",
201 [11] "Privileged register trap",
202 [12] "Overflow trap",
203 [13] "Conditional trap",
204 [14] "FP Assist Exception trap",
205 [15] "Data TLB miss fault",
206 [16] "Non-access ITLB miss fault",
207 [17] "Non-access DTLB miss fault",
208 [18] "Data memory protection/unaligned access trap",
209 [19] "Data memory break trap",
210 [20] "TLB dirty bit trap",
211 [21] "Page reference trap",
212 [22] "Assist emulation trap",
213 [25] "Taken branch trap",
214 [26] "Data memory access rights trap",
215 [27] "Data memory protection ID trap",
216 [28] "Unaligned data reference trap",
217 };
218
219 const char *trap_name(unsigned long code)
220 {
221 const char *t = NULL;
222
223 if (code < ARRAY_SIZE(trap_description))
224 t = trap_description[code];
225
226 return t ? t : "Unknown trap";
227 }
228
229 /*
230 * Print out info about fatal segfaults, if the show_unhandled_signals
231 * sysctl is set:
232 */
233 static inline void
234 show_signal_msg(struct pt_regs *regs, unsigned long code,
235 unsigned long address, struct task_struct *tsk,
236 struct vm_area_struct *vma)
237 {
238 if (!unhandled_signal(tsk, SIGSEGV))
239 return;
240
241 if (!printk_ratelimit())
242 return;
243
244 pr_warn("\n");
245 pr_warn("do_page_fault() command='%s' type=%lu address=0x%08lx",
246 tsk->comm, code, address);
247 print_vma_addr(KERN_CONT " in ", regs->iaoq[0]);
248
249 pr_cont("\ntrap #%lu: %s%c", code, trap_name(code),
250 vma ? ',':'\n');
251
252 if (vma)
253 pr_cont(" vm_start = 0x%08lx, vm_end = 0x%08lx\n",
254 vma->vm_start, vma->vm_end);
255
256 show_regs(regs);
257 }
258
259 void do_page_fault(struct pt_regs *regs, unsigned long code,
260 unsigned long address)
261 {
262 struct vm_area_struct *vma, *prev_vma;
263 struct task_struct *tsk;
264 struct mm_struct *mm;
265 unsigned long acc_type;
266 vm_fault_t fault = 0;
267 unsigned int flags;
268
269 if (faulthandler_disabled())
270 goto no_context;
271
272 tsk = current;
273 mm = tsk->mm;
274 if (!mm)
275 goto no_context;
276
277 flags = FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE;
278 if (user_mode(regs))
279 flags |= FAULT_FLAG_USER;
280
281 acc_type = parisc_acctyp(code, regs->iir);
282 if (acc_type & VM_WRITE)
283 flags |= FAULT_FLAG_WRITE;
284 retry:
285 down_read(&mm->mmap_sem);
286 vma = find_vma_prev(mm, address, &prev_vma);
287 if (!vma || address < vma->vm_start)
288 goto check_expansion;
289 /*
290 * Ok, we have a good vm_area for this memory access. We still need to
291 * check the access permissions.
292 */
293
294 good_area:
295
296 if ((vma->vm_flags & acc_type) != acc_type)
297 goto bad_area;
298
299 /*
300 * If for any reason at all we couldn't handle the fault, make
301 * sure we exit gracefully rather than endlessly redo the
302 * fault.
303 */
304
305 fault = handle_mm_fault(vma, address, flags);
306
307 if ((fault & VM_FAULT_RETRY) && fatal_signal_pending(current))
308 return;
309
310 if (unlikely(fault & VM_FAULT_ERROR)) {
311 /*
312 * We hit a shared mapping outside of the file, or some
313 * other thing happened to us that made us unable to
314 * handle the page fault gracefully.
315 */
316 if (fault & VM_FAULT_OOM)
317 goto out_of_memory;
318 else if (fault & VM_FAULT_SIGSEGV)
319 goto bad_area;
320 else if (fault & (VM_FAULT_SIGBUS|VM_FAULT_HWPOISON|
321 VM_FAULT_HWPOISON_LARGE))
322 goto bad_area;
323 BUG();
324 }
325 if (flags & FAULT_FLAG_ALLOW_RETRY) {
326 if (fault & VM_FAULT_MAJOR)
327 current->maj_flt++;
328 else
329 current->min_flt++;
330 if (fault & VM_FAULT_RETRY) {
331 flags &= ~FAULT_FLAG_ALLOW_RETRY;
332
333 /*
334 * No need to up_read(&mm->mmap_sem) as we would
335 * have already released it in __lock_page_or_retry
336 * in mm/filemap.c.
337 */
338
339 goto retry;
340 }
341 }
342 up_read(&mm->mmap_sem);
343 return;
344
345 check_expansion:
346 vma = prev_vma;
347 if (vma && (expand_stack(vma, address) == 0))
348 goto good_area;
349
350 /*
351 * Something tried to access memory that isn't in our memory map..
352 */
353 bad_area:
354 up_read(&mm->mmap_sem);
355
356 if (user_mode(regs)) {
357 int signo, si_code;
358
359 switch (code) {
360 case 15: /* Data TLB miss fault/Data page fault */
361 /* send SIGSEGV when outside of vma */
362 if (!vma ||
363 address < vma->vm_start || address >= vma->vm_end) {
364 signo = SIGSEGV;
365 si_code = SEGV_MAPERR;
366 break;
367 }
368
369 /* send SIGSEGV for wrong permissions */
370 if ((vma->vm_flags & acc_type) != acc_type) {
371 signo = SIGSEGV;
372 si_code = SEGV_ACCERR;
373 break;
374 }
375
376 /* probably address is outside of mapped file */
377 /* fall through */
378 case 17: /* NA data TLB miss / page fault */
379 case 18: /* Unaligned access - PCXS only */
380 signo = SIGBUS;
381 si_code = (code == 18) ? BUS_ADRALN : BUS_ADRERR;
382 break;
383 case 16: /* Non-access instruction TLB miss fault */
384 case 26: /* PCXL: Data memory access rights trap */
385 default:
386 signo = SIGSEGV;
387 si_code = (code == 26) ? SEGV_ACCERR : SEGV_MAPERR;
388 break;
389 }
390 #ifdef CONFIG_MEMORY_FAILURE
391 if (fault & (VM_FAULT_HWPOISON|VM_FAULT_HWPOISON_LARGE)) {
392 unsigned int lsb = 0;
393 printk(KERN_ERR
394 "MCE: Killing %s:%d due to hardware memory corruption fault at %08lx\n",
395 tsk->comm, tsk->pid, address);
396 /*
397 * Either small page or large page may be poisoned.
398 * In other words, VM_FAULT_HWPOISON_LARGE and
399 * VM_FAULT_HWPOISON are mutually exclusive.
400 */
401 if (fault & VM_FAULT_HWPOISON_LARGE)
402 lsb = hstate_index_to_shift(VM_FAULT_GET_HINDEX(fault));
403 else if (fault & VM_FAULT_HWPOISON)
404 lsb = PAGE_SHIFT;
405
406 force_sig_mceerr(BUS_MCEERR_AR, (void __user *) address,
407 lsb);
408 return;
409 }
410 #endif
411 show_signal_msg(regs, code, address, tsk, vma);
412
413 force_sig_fault(signo, si_code, (void __user *) address);
414 return;
415 }
416
417 no_context:
418
419 if (!user_mode(regs) && fixup_exception(regs)) {
420 return;
421 }
422
423 parisc_terminate("Bad Address (null pointer deref?)", regs, code, address);
424
425 out_of_memory:
426 up_read(&mm->mmap_sem);
427 if (!user_mode(regs))
428 goto no_context;
429 pagefault_out_of_memory();
430 }