1 /* 2 * unaligned.c: Unaligned load/store trap handling with special 3 * cases for the kernel to do them more quickly. 4 * 5 * Copyright (C) 1996,2008 David S. Miller (davem@davemloft.net) 6 * Copyright (C) 1996,1997 Jakub Jelinek (jj@sunsite.mff.cuni.cz) 7 */ 8 9 10 #include <linux/jiffies.h> 11 #include <linux/kernel.h> 12 #include <linux/sched.h> 13 #include <linux/mm.h> 14 #include <linux/module.h> 15 #include <asm/asi.h> 16 #include <asm/ptrace.h> 17 #include <asm/pstate.h> 18 #include <asm/processor.h> 19 #include <asm/system.h> 20 #include <asm/uaccess.h> 21 #include <linux/smp.h> 22 #include <linux/bitops.h> 23 #include <asm/fpumacro.h> 24 25 /* #define DEBUG_MNA */ 26 27 enum direction { 28 load, /* ld, ldd, ldh, ldsh */ 29 store, /* st, std, sth, stsh */ 30 both, /* Swap, ldstub, cas, ... */ 31 fpld, 32 fpst, 33 invalid, 34 }; 35 36 #ifdef DEBUG_MNA 37 static char *dirstrings[] = { 38 "load", "store", "both", "fpload", "fpstore", "invalid" 39 }; 40 #endif 41 42 static inline enum direction decode_direction(unsigned int insn) 43 { 44 unsigned long tmp = (insn >> 21) & 1; 45 46 if (!tmp) 47 return load; 48 else { 49 switch ((insn>>19)&0xf) { 50 case 15: /* swap* */ 51 return both; 52 default: 53 return store; 54 } 55 } 56 } 57 58 /* 16 = double-word, 8 = extra-word, 4 = word, 2 = half-word */ 59 static inline int decode_access_size(unsigned int insn) 60 { 61 unsigned int tmp; 62 63 tmp = ((insn >> 19) & 0xf); 64 if (tmp == 11 || tmp == 14) /* ldx/stx */ 65 return 8; 66 tmp &= 3; 67 if (!tmp) 68 return 4; 69 else if (tmp == 3) 70 return 16; /* ldd/std - Although it is actually 8 */ 71 else if (tmp == 2) 72 return 2; 73 else { 74 printk("Impossible unaligned trap. insn=%08x\n", insn); 75 die_if_kernel("Byte sized unaligned access?!?!", current_thread_info()->kregs); 76 77 /* GCC should never warn that control reaches the end 78 * of this function without returning a value because 79 * die_if_kernel() is marked with attribute 'noreturn'. 80 * Alas, some versions do... 81 */ 82 83 return 0; 84 } 85 } 86 87 static inline int decode_asi(unsigned int insn, struct pt_regs *regs) 88 { 89 if (insn & 0x800000) { 90 if (insn & 0x2000) 91 return (unsigned char)(regs->tstate >> 24); /* %asi */ 92 else 93 return (unsigned char)(insn >> 5); /* imm_asi */ 94 } else 95 return ASI_P; 96 } 97 98 /* 0x400000 = signed, 0 = unsigned */ 99 static inline int decode_signedness(unsigned int insn) 100 { 101 return (insn & 0x400000); 102 } 103 104 static inline void maybe_flush_windows(unsigned int rs1, unsigned int rs2, 105 unsigned int rd, int from_kernel) 106 { 107 if (rs2 >= 16 || rs1 >= 16 || rd >= 16) { 108 if (from_kernel != 0) 109 __asm__ __volatile__("flushw"); 110 else 111 flushw_user(); 112 } 113 } 114 115 static inline long sign_extend_imm13(long imm) 116 { 117 return imm << 51 >> 51; 118 } 119 120 static unsigned long fetch_reg(unsigned int reg, struct pt_regs *regs) 121 { 122 unsigned long value; 123 124 if (reg < 16) 125 return (!reg ? 0 : regs->u_regs[reg]); 126 if (regs->tstate & TSTATE_PRIV) { 127 struct reg_window *win; 128 win = (struct reg_window *)(regs->u_regs[UREG_FP] + STACK_BIAS); 129 value = win->locals[reg - 16]; 130 } else if (test_thread_flag(TIF_32BIT)) { 131 struct reg_window32 __user *win32; 132 win32 = (struct reg_window32 __user *)((unsigned long)((u32)regs->u_regs[UREG_FP])); 133 get_user(value, &win32->locals[reg - 16]); 134 } else { 135 struct reg_window __user *win; 136 win = (struct reg_window __user *)(regs->u_regs[UREG_FP] + STACK_BIAS); 137 get_user(value, &win->locals[reg - 16]); 138 } 139 return value; 140 } 141 142 static unsigned long *fetch_reg_addr(unsigned int reg, struct pt_regs *regs) 143 { 144 if (reg < 16) 145 return ®s->u_regs[reg]; 146 if (regs->tstate & TSTATE_PRIV) { 147 struct reg_window *win; 148 win = (struct reg_window *)(regs->u_regs[UREG_FP] + STACK_BIAS); 149 return &win->locals[reg - 16]; 150 } else if (test_thread_flag(TIF_32BIT)) { 151 struct reg_window32 *win32; 152 win32 = (struct reg_window32 *)((unsigned long)((u32)regs->u_regs[UREG_FP])); 153 return (unsigned long *)&win32->locals[reg - 16]; 154 } else { 155 struct reg_window *win; 156 win = (struct reg_window *)(regs->u_regs[UREG_FP] + STACK_BIAS); 157 return &win->locals[reg - 16]; 158 } 159 } 160 161 unsigned long compute_effective_address(struct pt_regs *regs, 162 unsigned int insn, unsigned int rd) 163 { 164 unsigned int rs1 = (insn >> 14) & 0x1f; 165 unsigned int rs2 = insn & 0x1f; 166 int from_kernel = (regs->tstate & TSTATE_PRIV) != 0; 167 168 if (insn & 0x2000) { 169 maybe_flush_windows(rs1, 0, rd, from_kernel); 170 return (fetch_reg(rs1, regs) + sign_extend_imm13(insn)); 171 } else { 172 maybe_flush_windows(rs1, rs2, rd, from_kernel); 173 return (fetch_reg(rs1, regs) + fetch_reg(rs2, regs)); 174 } 175 } 176 177 /* This is just to make gcc think die_if_kernel does return... */ 178 static void __used unaligned_panic(char *str, struct pt_regs *regs) 179 { 180 die_if_kernel(str, regs); 181 } 182 183 extern int do_int_load(unsigned long *dest_reg, int size, 184 unsigned long *saddr, int is_signed, int asi); 185 186 extern int __do_int_store(unsigned long *dst_addr, int size, 187 unsigned long src_val, int asi); 188 189 static inline int do_int_store(int reg_num, int size, unsigned long *dst_addr, 190 struct pt_regs *regs, int asi, int orig_asi) 191 { 192 unsigned long zero = 0; 193 unsigned long *src_val_p = &zero; 194 unsigned long src_val; 195 196 if (size == 16) { 197 size = 8; 198 zero = (((long)(reg_num ? 199 (unsigned)fetch_reg(reg_num, regs) : 0)) << 32) | 200 (unsigned)fetch_reg(reg_num + 1, regs); 201 } else if (reg_num) { 202 src_val_p = fetch_reg_addr(reg_num, regs); 203 } 204 src_val = *src_val_p; 205 if (unlikely(asi != orig_asi)) { 206 switch (size) { 207 case 2: 208 src_val = swab16(src_val); 209 break; 210 case 4: 211 src_val = swab32(src_val); 212 break; 213 case 8: 214 src_val = swab64(src_val); 215 break; 216 case 16: 217 default: 218 BUG(); 219 break; 220 }; 221 } 222 return __do_int_store(dst_addr, size, src_val, asi); 223 } 224 225 static inline void advance(struct pt_regs *regs) 226 { 227 regs->tpc = regs->tnpc; 228 regs->tnpc += 4; 229 if (test_thread_flag(TIF_32BIT)) { 230 regs->tpc &= 0xffffffff; 231 regs->tnpc &= 0xffffffff; 232 } 233 } 234 235 static inline int floating_point_load_or_store_p(unsigned int insn) 236 { 237 return (insn >> 24) & 1; 238 } 239 240 static inline int ok_for_kernel(unsigned int insn) 241 { 242 return !floating_point_load_or_store_p(insn); 243 } 244 245 static void kernel_mna_trap_fault(int fixup_tstate_asi) 246 { 247 struct pt_regs *regs = current_thread_info()->kern_una_regs; 248 unsigned int insn = current_thread_info()->kern_una_insn; 249 const struct exception_table_entry *entry; 250 251 entry = search_exception_tables(regs->tpc); 252 if (!entry) { 253 unsigned long address; 254 255 address = compute_effective_address(regs, insn, 256 ((insn >> 25) & 0x1f)); 257 if (address < PAGE_SIZE) { 258 printk(KERN_ALERT "Unable to handle kernel NULL " 259 "pointer dereference in mna handler"); 260 } else 261 printk(KERN_ALERT "Unable to handle kernel paging " 262 "request in mna handler"); 263 printk(KERN_ALERT " at virtual address %016lx\n",address); 264 printk(KERN_ALERT "current->{active_,}mm->context = %016lx\n", 265 (current->mm ? CTX_HWBITS(current->mm->context) : 266 CTX_HWBITS(current->active_mm->context))); 267 printk(KERN_ALERT "current->{active_,}mm->pgd = %016lx\n", 268 (current->mm ? (unsigned long) current->mm->pgd : 269 (unsigned long) current->active_mm->pgd)); 270 die_if_kernel("Oops", regs); 271 /* Not reached */ 272 } 273 regs->tpc = entry->fixup; 274 regs->tnpc = regs->tpc + 4; 275 276 if (fixup_tstate_asi) { 277 regs->tstate &= ~TSTATE_ASI; 278 regs->tstate |= (ASI_AIUS << 24UL); 279 } 280 } 281 282 static void log_unaligned(struct pt_regs *regs) 283 { 284 static unsigned long count, last_time; 285 286 if (time_after(jiffies, last_time + 5 * HZ)) 287 count = 0; 288 if (count < 5) { 289 last_time = jiffies; 290 count++; 291 printk("Kernel unaligned access at TPC[%lx] %pS\n", 292 regs->tpc, (void *) regs->tpc); 293 } 294 } 295 296 asmlinkage void kernel_unaligned_trap(struct pt_regs *regs, unsigned int insn) 297 { 298 enum direction dir = decode_direction(insn); 299 int size = decode_access_size(insn); 300 int orig_asi, asi; 301 302 current_thread_info()->kern_una_regs = regs; 303 current_thread_info()->kern_una_insn = insn; 304 305 orig_asi = asi = decode_asi(insn, regs); 306 307 /* If this is a {get,put}_user() on an unaligned userspace pointer, 308 * just signal a fault and do not log the event. 309 */ 310 if (asi == ASI_AIUS) { 311 kernel_mna_trap_fault(0); 312 return; 313 } 314 315 log_unaligned(regs); 316 317 if (!ok_for_kernel(insn) || dir == both) { 318 printk("Unsupported unaligned load/store trap for kernel " 319 "at <%016lx>.\n", regs->tpc); 320 unaligned_panic("Kernel does fpu/atomic " 321 "unaligned load/store.", regs); 322 323 kernel_mna_trap_fault(0); 324 } else { 325 unsigned long addr, *reg_addr; 326 int err; 327 328 addr = compute_effective_address(regs, insn, 329 ((insn >> 25) & 0x1f)); 330 #ifdef DEBUG_MNA 331 printk("KMNA: pc=%016lx [dir=%s addr=%016lx size=%d] " 332 "retpc[%016lx]\n", 333 regs->tpc, dirstrings[dir], addr, size, 334 regs->u_regs[UREG_RETPC]); 335 #endif 336 switch (asi) { 337 case ASI_NL: 338 case ASI_AIUPL: 339 case ASI_AIUSL: 340 case ASI_PL: 341 case ASI_SL: 342 case ASI_PNFL: 343 case ASI_SNFL: 344 asi &= ~0x08; 345 break; 346 }; 347 switch (dir) { 348 case load: 349 reg_addr = fetch_reg_addr(((insn>>25)&0x1f), regs); 350 err = do_int_load(reg_addr, size, 351 (unsigned long *) addr, 352 decode_signedness(insn), asi); 353 if (likely(!err) && unlikely(asi != orig_asi)) { 354 unsigned long val_in = *reg_addr; 355 switch (size) { 356 case 2: 357 val_in = swab16(val_in); 358 break; 359 case 4: 360 val_in = swab32(val_in); 361 break; 362 case 8: 363 val_in = swab64(val_in); 364 break; 365 case 16: 366 default: 367 BUG(); 368 break; 369 }; 370 *reg_addr = val_in; 371 } 372 break; 373 374 case store: 375 err = do_int_store(((insn>>25)&0x1f), size, 376 (unsigned long *) addr, regs, 377 asi, orig_asi); 378 break; 379 380 default: 381 panic("Impossible kernel unaligned trap."); 382 /* Not reached... */ 383 } 384 if (unlikely(err)) 385 kernel_mna_trap_fault(1); 386 else 387 advance(regs); 388 } 389 } 390 391 static char popc_helper[] = { 392 0, 1, 1, 2, 1, 2, 2, 3, 393 1, 2, 2, 3, 2, 3, 3, 4, 394 }; 395 396 int handle_popc(u32 insn, struct pt_regs *regs) 397 { 398 u64 value; 399 int ret, i, rd = ((insn >> 25) & 0x1f); 400 int from_kernel = (regs->tstate & TSTATE_PRIV) != 0; 401 402 if (insn & 0x2000) { 403 maybe_flush_windows(0, 0, rd, from_kernel); 404 value = sign_extend_imm13(insn); 405 } else { 406 maybe_flush_windows(0, insn & 0x1f, rd, from_kernel); 407 value = fetch_reg(insn & 0x1f, regs); 408 } 409 for (ret = 0, i = 0; i < 16; i++) { 410 ret += popc_helper[value & 0xf]; 411 value >>= 4; 412 } 413 if (rd < 16) { 414 if (rd) 415 regs->u_regs[rd] = ret; 416 } else { 417 if (test_thread_flag(TIF_32BIT)) { 418 struct reg_window32 __user *win32; 419 win32 = (struct reg_window32 __user *)((unsigned long)((u32)regs->u_regs[UREG_FP])); 420 put_user(ret, &win32->locals[rd - 16]); 421 } else { 422 struct reg_window __user *win; 423 win = (struct reg_window __user *)(regs->u_regs[UREG_FP] + STACK_BIAS); 424 put_user(ret, &win->locals[rd - 16]); 425 } 426 } 427 advance(regs); 428 return 1; 429 } 430 431 extern void do_fpother(struct pt_regs *regs); 432 extern void do_privact(struct pt_regs *regs); 433 extern void spitfire_data_access_exception(struct pt_regs *regs, 434 unsigned long sfsr, 435 unsigned long sfar); 436 extern void sun4v_data_access_exception(struct pt_regs *regs, 437 unsigned long addr, 438 unsigned long type_ctx); 439 440 int handle_ldf_stq(u32 insn, struct pt_regs *regs) 441 { 442 unsigned long addr = compute_effective_address(regs, insn, 0); 443 int freg = ((insn >> 25) & 0x1e) | ((insn >> 20) & 0x20); 444 struct fpustate *f = FPUSTATE; 445 int asi = decode_asi(insn, regs); 446 int flag = (freg < 32) ? FPRS_DL : FPRS_DU; 447 448 save_and_clear_fpu(); 449 current_thread_info()->xfsr[0] &= ~0x1c000; 450 if (freg & 3) { 451 current_thread_info()->xfsr[0] |= (6 << 14) /* invalid_fp_register */; 452 do_fpother(regs); 453 return 0; 454 } 455 if (insn & 0x200000) { 456 /* STQ */ 457 u64 first = 0, second = 0; 458 459 if (current_thread_info()->fpsaved[0] & flag) { 460 first = *(u64 *)&f->regs[freg]; 461 second = *(u64 *)&f->regs[freg+2]; 462 } 463 if (asi < 0x80) { 464 do_privact(regs); 465 return 1; 466 } 467 switch (asi) { 468 case ASI_P: 469 case ASI_S: break; 470 case ASI_PL: 471 case ASI_SL: 472 { 473 /* Need to convert endians */ 474 u64 tmp = __swab64p(&first); 475 476 first = __swab64p(&second); 477 second = tmp; 478 break; 479 } 480 default: 481 if (tlb_type == hypervisor) 482 sun4v_data_access_exception(regs, addr, 0); 483 else 484 spitfire_data_access_exception(regs, 0, addr); 485 return 1; 486 } 487 if (put_user (first >> 32, (u32 __user *)addr) || 488 __put_user ((u32)first, (u32 __user *)(addr + 4)) || 489 __put_user (second >> 32, (u32 __user *)(addr + 8)) || 490 __put_user ((u32)second, (u32 __user *)(addr + 12))) { 491 if (tlb_type == hypervisor) 492 sun4v_data_access_exception(regs, addr, 0); 493 else 494 spitfire_data_access_exception(regs, 0, addr); 495 return 1; 496 } 497 } else { 498 /* LDF, LDDF, LDQF */ 499 u32 data[4] __attribute__ ((aligned(8))); 500 int size, i; 501 int err; 502 503 if (asi < 0x80) { 504 do_privact(regs); 505 return 1; 506 } else if (asi > ASI_SNFL) { 507 if (tlb_type == hypervisor) 508 sun4v_data_access_exception(regs, addr, 0); 509 else 510 spitfire_data_access_exception(regs, 0, addr); 511 return 1; 512 } 513 switch (insn & 0x180000) { 514 case 0x000000: size = 1; break; 515 case 0x100000: size = 4; break; 516 default: size = 2; break; 517 } 518 for (i = 0; i < size; i++) 519 data[i] = 0; 520 521 err = get_user (data[0], (u32 __user *) addr); 522 if (!err) { 523 for (i = 1; i < size; i++) 524 err |= __get_user (data[i], (u32 __user *)(addr + 4*i)); 525 } 526 if (err && !(asi & 0x2 /* NF */)) { 527 if (tlb_type == hypervisor) 528 sun4v_data_access_exception(regs, addr, 0); 529 else 530 spitfire_data_access_exception(regs, 0, addr); 531 return 1; 532 } 533 if (asi & 0x8) /* Little */ { 534 u64 tmp; 535 536 switch (size) { 537 case 1: data[0] = le32_to_cpup(data + 0); break; 538 default:*(u64 *)(data + 0) = le64_to_cpup((u64 *)(data + 0)); 539 break; 540 case 4: tmp = le64_to_cpup((u64 *)(data + 0)); 541 *(u64 *)(data + 0) = le64_to_cpup((u64 *)(data + 2)); 542 *(u64 *)(data + 2) = tmp; 543 break; 544 } 545 } 546 if (!(current_thread_info()->fpsaved[0] & FPRS_FEF)) { 547 current_thread_info()->fpsaved[0] = FPRS_FEF; 548 current_thread_info()->gsr[0] = 0; 549 } 550 if (!(current_thread_info()->fpsaved[0] & flag)) { 551 if (freg < 32) 552 memset(f->regs, 0, 32*sizeof(u32)); 553 else 554 memset(f->regs+32, 0, 32*sizeof(u32)); 555 } 556 memcpy(f->regs + freg, data, size * 4); 557 current_thread_info()->fpsaved[0] |= flag; 558 } 559 advance(regs); 560 return 1; 561 } 562 563 void handle_ld_nf(u32 insn, struct pt_regs *regs) 564 { 565 int rd = ((insn >> 25) & 0x1f); 566 int from_kernel = (regs->tstate & TSTATE_PRIV) != 0; 567 unsigned long *reg; 568 569 maybe_flush_windows(0, 0, rd, from_kernel); 570 reg = fetch_reg_addr(rd, regs); 571 if (from_kernel || rd < 16) { 572 reg[0] = 0; 573 if ((insn & 0x780000) == 0x180000) 574 reg[1] = 0; 575 } else if (test_thread_flag(TIF_32BIT)) { 576 put_user(0, (int __user *) reg); 577 if ((insn & 0x780000) == 0x180000) 578 put_user(0, ((int __user *) reg) + 1); 579 } else { 580 put_user(0, (unsigned long __user *) reg); 581 if ((insn & 0x780000) == 0x180000) 582 put_user(0, (unsigned long __user *) reg + 1); 583 } 584 advance(regs); 585 } 586 587 void handle_lddfmna(struct pt_regs *regs, unsigned long sfar, unsigned long sfsr) 588 { 589 unsigned long pc = regs->tpc; 590 unsigned long tstate = regs->tstate; 591 u32 insn; 592 u64 value; 593 u8 freg; 594 int flag; 595 struct fpustate *f = FPUSTATE; 596 597 if (tstate & TSTATE_PRIV) 598 die_if_kernel("lddfmna from kernel", regs); 599 if (test_thread_flag(TIF_32BIT)) 600 pc = (u32)pc; 601 if (get_user(insn, (u32 __user *) pc) != -EFAULT) { 602 int asi = decode_asi(insn, regs); 603 u32 first, second; 604 int err; 605 606 if ((asi > ASI_SNFL) || 607 (asi < ASI_P)) 608 goto daex; 609 first = second = 0; 610 err = get_user(first, (u32 __user *)sfar); 611 if (!err) 612 err = get_user(second, (u32 __user *)(sfar + 4)); 613 if (err) { 614 if (!(asi & 0x2)) 615 goto daex; 616 first = second = 0; 617 } 618 save_and_clear_fpu(); 619 freg = ((insn >> 25) & 0x1e) | ((insn >> 20) & 0x20); 620 value = (((u64)first) << 32) | second; 621 if (asi & 0x8) /* Little */ 622 value = __swab64p(&value); 623 flag = (freg < 32) ? FPRS_DL : FPRS_DU; 624 if (!(current_thread_info()->fpsaved[0] & FPRS_FEF)) { 625 current_thread_info()->fpsaved[0] = FPRS_FEF; 626 current_thread_info()->gsr[0] = 0; 627 } 628 if (!(current_thread_info()->fpsaved[0] & flag)) { 629 if (freg < 32) 630 memset(f->regs, 0, 32*sizeof(u32)); 631 else 632 memset(f->regs+32, 0, 32*sizeof(u32)); 633 } 634 *(u64 *)(f->regs + freg) = value; 635 current_thread_info()->fpsaved[0] |= flag; 636 } else { 637 daex: 638 if (tlb_type == hypervisor) 639 sun4v_data_access_exception(regs, sfar, sfsr); 640 else 641 spitfire_data_access_exception(regs, sfsr, sfar); 642 return; 643 } 644 advance(regs); 645 return; 646 } 647 648 void handle_stdfmna(struct pt_regs *regs, unsigned long sfar, unsigned long sfsr) 649 { 650 unsigned long pc = regs->tpc; 651 unsigned long tstate = regs->tstate; 652 u32 insn; 653 u64 value; 654 u8 freg; 655 int flag; 656 struct fpustate *f = FPUSTATE; 657 658 if (tstate & TSTATE_PRIV) 659 die_if_kernel("stdfmna from kernel", regs); 660 if (test_thread_flag(TIF_32BIT)) 661 pc = (u32)pc; 662 if (get_user(insn, (u32 __user *) pc) != -EFAULT) { 663 int asi = decode_asi(insn, regs); 664 freg = ((insn >> 25) & 0x1e) | ((insn >> 20) & 0x20); 665 value = 0; 666 flag = (freg < 32) ? FPRS_DL : FPRS_DU; 667 if ((asi > ASI_SNFL) || 668 (asi < ASI_P)) 669 goto daex; 670 save_and_clear_fpu(); 671 if (current_thread_info()->fpsaved[0] & flag) 672 value = *(u64 *)&f->regs[freg]; 673 switch (asi) { 674 case ASI_P: 675 case ASI_S: break; 676 case ASI_PL: 677 case ASI_SL: 678 value = __swab64p(&value); break; 679 default: goto daex; 680 } 681 if (put_user (value >> 32, (u32 __user *) sfar) || 682 __put_user ((u32)value, (u32 __user *)(sfar + 4))) 683 goto daex; 684 } else { 685 daex: 686 if (tlb_type == hypervisor) 687 sun4v_data_access_exception(regs, sfar, sfsr); 688 else 689 spitfire_data_access_exception(regs, sfsr, sfar); 690 return; 691 } 692 advance(regs); 693 return; 694 } 695