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#include <linux/perf_event.h> 22 23#include <asm/traps.h> 24 25/* Various important other fields */ 26#define bit22set(x) (x & 0x00000200) 27#define bits23_25set(x) (x & 0x000001c0) 28#define isGraphicsFlushRead(x) ((x & 0xfc003fdf) == 0x04001a80) 29 /* extended opcode is 0x6a */ 30 31#define BITSSET 0x1c0 /* for identifying LDCW */ 32 33 34int show_unhandled_signals = 1; 35 36/* 37 * parisc_acctyp(unsigned int inst) -- 38 * Given a PA-RISC memory access instruction, determine if the 39 * the instruction would perform a memory read or memory write 40 * operation. 41 * 42 * This function assumes that the given instruction is a memory access 43 * instruction (i.e. you should really only call it if you know that 44 * the instruction has generated some sort of a memory access fault). 45 * 46 * Returns: 47 * VM_READ if read operation 48 * VM_WRITE if write operation 49 * VM_EXEC if execute operation 50 */ 51static unsigned long 52parisc_acctyp(unsigned long code, unsigned int inst) 53{ 54 if (code == 6 || code == 16) 55 return VM_EXEC; 56 57 switch (inst & 0xf0000000) { 58 case 0x40000000: /* load */ 59 case 0x50000000: /* new load */ 60 return VM_READ; 61 62 case 0x60000000: /* store */ 63 case 0x70000000: /* new store */ 64 return VM_WRITE; 65 66 case 0x20000000: /* coproc */ 67 case 0x30000000: /* coproc2 */ 68 if (bit22set(inst)) 69 return VM_WRITE; 70 fallthrough; 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 141int fixup_exception(struct pt_regs *regs) 142{ 143 const struct exception_table_entry *fix; 144 145 fix = search_exception_tables(regs->iaoq[0]); 146 if (fix) { 147 /* 148 * Fix up get_user() and put_user(). 149 * ASM_EXCEPTIONTABLE_ENTRY_EFAULT() sets the least-significant 150 * bit in the relative address of the fixup routine to indicate 151 * that %r8 should be loaded with -EFAULT to report a userspace 152 * access error. 153 */ 154 if (fix->fixup & 1) { 155 regs->gr[8] = -EFAULT; 156 157 /* zero target register for get_user() */ 158 if (parisc_acctyp(0, regs->iir) == VM_READ) { 159 int treg = regs->iir & 0x1f; 160 BUG_ON(treg == 0); 161 regs->gr[treg] = 0; 162 } 163 } 164 165 regs->iaoq[0] = (unsigned long)&fix->fixup + fix->fixup; 166 regs->iaoq[0] &= ~3; 167 /* 168 * NOTE: In some cases the faulting instruction 169 * may be in the delay slot of a branch. We 170 * don't want to take the branch, so we don't 171 * increment iaoq[1], instead we set it to be 172 * iaoq[0]+4, and clear the B bit in the PSW 173 */ 174 regs->iaoq[1] = regs->iaoq[0] + 4; 175 regs->gr[0] &= ~PSW_B; /* IPSW in gr[0] */ 176 177 return 1; 178 } 179 180 return 0; 181} 182 183/* 184 * parisc hardware trap list 185 * 186 * Documented in section 3 "Addressing and Access Control" of the 187 * "PA-RISC 1.1 Architecture and Instruction Set Reference Manual" 188 * https://parisc.wiki.kernel.org/index.php/File:Pa11_acd.pdf 189 * 190 * For implementation see handle_interruption() in traps.c 191 */ 192static const char * const trap_description[] = { 193 [1] "High-priority machine check (HPMC)", 194 [2] "Power failure interrupt", 195 [3] "Recovery counter trap", 196 [5] "Low-priority machine check", 197 [6] "Instruction TLB miss fault", 198 [7] "Instruction access rights / protection trap", 199 [8] "Illegal instruction trap", 200 [9] "Break instruction trap", 201 [10] "Privileged operation trap", 202 [11] "Privileged register trap", 203 [12] "Overflow trap", 204 [13] "Conditional trap", 205 [14] "FP Assist Exception trap", 206 [15] "Data TLB miss fault", 207 [16] "Non-access ITLB miss fault", 208 [17] "Non-access DTLB miss fault", 209 [18] "Data memory protection/unaligned access trap", 210 [19] "Data memory break trap", 211 [20] "TLB dirty bit trap", 212 [21] "Page reference trap", 213 [22] "Assist emulation trap", 214 [25] "Taken branch trap", 215 [26] "Data memory access rights trap", 216 [27] "Data memory protection ID trap", 217 [28] "Unaligned data reference trap", 218}; 219 220const char *trap_name(unsigned long code) 221{ 222 const char *t = NULL; 223 224 if (code < ARRAY_SIZE(trap_description)) 225 t = trap_description[code]; 226 227 return t ? t : "Unknown trap"; 228} 229 230/* 231 * Print out info about fatal segfaults, if the show_unhandled_signals 232 * sysctl is set: 233 */ 234static inline void 235show_signal_msg(struct pt_regs *regs, unsigned long code, 236 unsigned long address, struct task_struct *tsk, 237 struct vm_area_struct *vma) 238{ 239 if (!unhandled_signal(tsk, SIGSEGV)) 240 return; 241 242 if (!printk_ratelimit()) 243 return; 244 245 pr_warn("\n"); 246 pr_warn("do_page_fault() command='%s' type=%lu address=0x%08lx", 247 tsk->comm, code, address); 248 print_vma_addr(KERN_CONT " in ", regs->iaoq[0]); 249 250 pr_cont("\ntrap #%lu: %s%c", code, trap_name(code), 251 vma ? ',':'\n'); 252 253 if (vma) 254 pr_cont(" vm_start = 0x%08lx, vm_end = 0x%08lx\n", 255 vma->vm_start, vma->vm_end); 256 257 show_regs(regs); 258} 259 260void do_page_fault(struct pt_regs *regs, unsigned long code, 261 unsigned long address) 262{ 263 struct vm_area_struct *vma, *prev_vma; 264 struct task_struct *tsk; 265 struct mm_struct *mm; 266 unsigned long acc_type; 267 vm_fault_t fault = 0; 268 unsigned int flags; 269 270 if (faulthandler_disabled()) 271 goto no_context; 272 273 tsk = current; 274 mm = tsk->mm; 275 if (!mm) 276 goto no_context; 277 278 flags = FAULT_FLAG_DEFAULT; 279 if (user_mode(regs)) 280 flags |= FAULT_FLAG_USER; 281 282 acc_type = parisc_acctyp(code, regs->iir); 283 if (acc_type & VM_WRITE) 284 flags |= FAULT_FLAG_WRITE; 285 perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS, 1, regs, address); 286retry: 287 mmap_read_lock(mm); 288 vma = find_vma_prev(mm, address, &prev_vma); 289 if (!vma || address < vma->vm_start) 290 goto check_expansion; 291/* 292 * Ok, we have a good vm_area for this memory access. We still need to 293 * check the access permissions. 294 */ 295 296good_area: 297 298 if ((vma->vm_flags & acc_type) != acc_type) 299 goto bad_area; 300 301 /* 302 * If for any reason at all we couldn't handle the fault, make 303 * sure we exit gracefully rather than endlessly redo the 304 * fault. 305 */ 306 307 fault = handle_mm_fault(vma, address, flags, regs); 308 309 if (fault_signal_pending(fault, regs)) 310 return; 311 312 if (unlikely(fault & VM_FAULT_ERROR)) { 313 /* 314 * We hit a shared mapping outside of the file, or some 315 * other thing happened to us that made us unable to 316 * handle the page fault gracefully. 317 */ 318 if (fault & VM_FAULT_OOM) 319 goto out_of_memory; 320 else if (fault & VM_FAULT_SIGSEGV) 321 goto bad_area; 322 else if (fault & (VM_FAULT_SIGBUS|VM_FAULT_HWPOISON| 323 VM_FAULT_HWPOISON_LARGE)) 324 goto bad_area; 325 BUG(); 326 } 327 if (flags & FAULT_FLAG_ALLOW_RETRY) { 328 if (fault & VM_FAULT_RETRY) { 329 /* 330 * No need to mmap_read_unlock(mm) as we would 331 * have already released it in __lock_page_or_retry 332 * in mm/filemap.c. 333 */ 334 flags |= FAULT_FLAG_TRIED; 335 goto retry; 336 } 337 } 338 mmap_read_unlock(mm); 339 return; 340 341check_expansion: 342 vma = prev_vma; 343 if (vma && (expand_stack(vma, address) == 0)) 344 goto good_area; 345 346/* 347 * Something tried to access memory that isn't in our memory map.. 348 */ 349bad_area: 350 mmap_read_unlock(mm); 351 352 if (user_mode(regs)) { 353 int signo, si_code; 354 355 switch (code) { 356 case 15: /* Data TLB miss fault/Data page fault */ 357 /* send SIGSEGV when outside of vma */ 358 if (!vma || 359 address < vma->vm_start || address >= vma->vm_end) { 360 signo = SIGSEGV; 361 si_code = SEGV_MAPERR; 362 break; 363 } 364 365 /* send SIGSEGV for wrong permissions */ 366 if ((vma->vm_flags & acc_type) != acc_type) { 367 signo = SIGSEGV; 368 si_code = SEGV_ACCERR; 369 break; 370 } 371 372 /* probably address is outside of mapped file */ 373 fallthrough; 374 case 17: /* NA data TLB miss / page fault */ 375 case 18: /* Unaligned access - PCXS only */ 376 signo = SIGBUS; 377 si_code = (code == 18) ? BUS_ADRALN : BUS_ADRERR; 378 break; 379 case 16: /* Non-access instruction TLB miss fault */ 380 case 26: /* PCXL: Data memory access rights trap */ 381 default: 382 signo = SIGSEGV; 383 si_code = (code == 26) ? SEGV_ACCERR : SEGV_MAPERR; 384 break; 385 } 386#ifdef CONFIG_MEMORY_FAILURE 387 if (fault & (VM_FAULT_HWPOISON|VM_FAULT_HWPOISON_LARGE)) { 388 unsigned int lsb = 0; 389 printk(KERN_ERR 390 "MCE: Killing %s:%d due to hardware memory corruption fault at %08lx\n", 391 tsk->comm, tsk->pid, address); 392 /* 393 * Either small page or large page may be poisoned. 394 * In other words, VM_FAULT_HWPOISON_LARGE and 395 * VM_FAULT_HWPOISON are mutually exclusive. 396 */ 397 if (fault & VM_FAULT_HWPOISON_LARGE) 398 lsb = hstate_index_to_shift(VM_FAULT_GET_HINDEX(fault)); 399 else if (fault & VM_FAULT_HWPOISON) 400 lsb = PAGE_SHIFT; 401 402 force_sig_mceerr(BUS_MCEERR_AR, (void __user *) address, 403 lsb); 404 return; 405 } 406#endif 407 show_signal_msg(regs, code, address, tsk, vma); 408 409 force_sig_fault(signo, si_code, (void __user *) address); 410 return; 411 } 412 413no_context: 414 415 if (!user_mode(regs) && fixup_exception(regs)) { 416 return; 417 } 418 419 parisc_terminate("Bad Address (null pointer deref?)", regs, code, address); 420 421 out_of_memory: 422 mmap_read_unlock(mm); 423 if (!user_mode(regs)) 424 goto no_context; 425 pagefault_out_of_memory(); 426} 427 428/* Handle non-access data TLB miss faults. 429 * 430 * For probe instructions, accesses to userspace are considered allowed 431 * if they lie in a valid VMA and the access type matches. We are not 432 * allowed to handle MM faults here so there may be situations where an 433 * actual access would fail even though a probe was successful. 434 */ 435int 436handle_nadtlb_fault(struct pt_regs *regs) 437{ 438 unsigned long insn = regs->iir; 439 int breg, treg, xreg, val = 0; 440 struct vm_area_struct *vma, *prev_vma; 441 struct task_struct *tsk; 442 struct mm_struct *mm; 443 unsigned long address; 444 unsigned long acc_type; 445 446 switch (insn & 0x380) { 447 case 0x280: 448 /* FDC instruction */ 449 fallthrough; 450 case 0x380: 451 /* PDC and FIC instructions */ 452 if (printk_ratelimit()) { 453 pr_warn("BUG: nullifying cache flush/purge instruction\n"); 454 show_regs(regs); 455 } 456 if (insn & 0x20) { 457 /* Base modification */ 458 breg = (insn >> 21) & 0x1f; 459 xreg = (insn >> 16) & 0x1f; 460 if (breg && xreg) 461 regs->gr[breg] += regs->gr[xreg]; 462 } 463 regs->gr[0] |= PSW_N; 464 return 1; 465 466 case 0x180: 467 /* PROBE instruction */ 468 treg = insn & 0x1f; 469 if (regs->isr) { 470 tsk = current; 471 mm = tsk->mm; 472 if (mm) { 473 /* Search for VMA */ 474 address = regs->ior; 475 mmap_read_lock(mm); 476 vma = find_vma_prev(mm, address, &prev_vma); 477 mmap_read_unlock(mm); 478 479 /* 480 * Check if access to the VMA is okay. 481 * We don't allow for stack expansion. 482 */ 483 acc_type = (insn & 0x40) ? VM_WRITE : VM_READ; 484 if (vma 485 && address >= vma->vm_start 486 && (vma->vm_flags & acc_type) == acc_type) 487 val = 1; 488 } 489 } 490 if (treg) 491 regs->gr[treg] = val; 492 regs->gr[0] |= PSW_N; 493 return 1; 494 495 case 0x300: 496 /* LPA instruction */ 497 if (insn & 0x20) { 498 /* Base modification */ 499 breg = (insn >> 21) & 0x1f; 500 xreg = (insn >> 16) & 0x1f; 501 if (breg && xreg) 502 regs->gr[breg] += regs->gr[xreg]; 503 } 504 treg = insn & 0x1f; 505 if (treg) 506 regs->gr[treg] = 0; 507 regs->gr[0] |= PSW_N; 508 return 1; 509 510 default: 511 break; 512 } 513 514 return 0; 515} 516