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 * Copyright (C) 1996, 97, 2000, 2001 by Ralf Baechle 7 * Copyright (C) 2001 MIPS Technologies, Inc. 8 */ 9 #include <linux/kernel.h> 10 #include <linux/sched/signal.h> 11 #include <linux/signal.h> 12 #include <linux/export.h> 13 #include <asm/branch.h> 14 #include <asm/cpu.h> 15 #include <asm/cpu-features.h> 16 #include <asm/fpu.h> 17 #include <asm/fpu_emulator.h> 18 #include <asm/inst.h> 19 #include <asm/mips-r2-to-r6-emul.h> 20 #include <asm/ptrace.h> 21 #include <linux/uaccess.h> 22 23 /* 24 * Calculate and return exception PC in case of branch delay slot 25 * for microMIPS and MIPS16e. It does not clear the ISA mode bit. 26 */ 27 int __isa_exception_epc(struct pt_regs *regs) 28 { 29 unsigned short inst; 30 long epc = regs->cp0_epc; 31 32 /* Calculate exception PC in branch delay slot. */ 33 if (__get_user(inst, (u16 __user *) msk_isa16_mode(epc))) { 34 /* This should never happen because delay slot was checked. */ 35 force_sig(SIGSEGV, current); 36 return epc; 37 } 38 if (cpu_has_mips16) { 39 union mips16e_instruction inst_mips16e; 40 41 inst_mips16e.full = inst; 42 if (inst_mips16e.ri.opcode == MIPS16e_jal_op) 43 epc += 4; 44 else 45 epc += 2; 46 } else if (mm_insn_16bit(inst)) 47 epc += 2; 48 else 49 epc += 4; 50 51 return epc; 52 } 53 54 /* (microMIPS) Convert 16-bit register encoding to 32-bit register encoding. */ 55 static const unsigned int reg16to32map[8] = {16, 17, 2, 3, 4, 5, 6, 7}; 56 57 int __mm_isBranchInstr(struct pt_regs *regs, struct mm_decoded_insn dec_insn, 58 unsigned long *contpc) 59 { 60 union mips_instruction insn = (union mips_instruction)dec_insn.insn; 61 int bc_false = 0; 62 unsigned int fcr31; 63 unsigned int bit; 64 65 if (!cpu_has_mmips) 66 return 0; 67 68 switch (insn.mm_i_format.opcode) { 69 case mm_pool32a_op: 70 if ((insn.mm_i_format.simmediate & MM_POOL32A_MINOR_MASK) == 71 mm_pool32axf_op) { 72 switch (insn.mm_i_format.simmediate >> 73 MM_POOL32A_MINOR_SHIFT) { 74 case mm_jalr_op: 75 case mm_jalrhb_op: 76 case mm_jalrs_op: 77 case mm_jalrshb_op: 78 if (insn.mm_i_format.rt != 0) /* Not mm_jr */ 79 regs->regs[insn.mm_i_format.rt] = 80 regs->cp0_epc + 81 dec_insn.pc_inc + 82 dec_insn.next_pc_inc; 83 *contpc = regs->regs[insn.mm_i_format.rs]; 84 return 1; 85 } 86 } 87 break; 88 case mm_pool32i_op: 89 switch (insn.mm_i_format.rt) { 90 case mm_bltzals_op: 91 case mm_bltzal_op: 92 regs->regs[31] = regs->cp0_epc + 93 dec_insn.pc_inc + 94 dec_insn.next_pc_inc; 95 /* Fall through */ 96 case mm_bltz_op: 97 if ((long)regs->regs[insn.mm_i_format.rs] < 0) 98 *contpc = regs->cp0_epc + 99 dec_insn.pc_inc + 100 (insn.mm_i_format.simmediate << 1); 101 else 102 *contpc = regs->cp0_epc + 103 dec_insn.pc_inc + 104 dec_insn.next_pc_inc; 105 return 1; 106 case mm_bgezals_op: 107 case mm_bgezal_op: 108 regs->regs[31] = regs->cp0_epc + 109 dec_insn.pc_inc + 110 dec_insn.next_pc_inc; 111 /* Fall through */ 112 case mm_bgez_op: 113 if ((long)regs->regs[insn.mm_i_format.rs] >= 0) 114 *contpc = regs->cp0_epc + 115 dec_insn.pc_inc + 116 (insn.mm_i_format.simmediate << 1); 117 else 118 *contpc = regs->cp0_epc + 119 dec_insn.pc_inc + 120 dec_insn.next_pc_inc; 121 return 1; 122 case mm_blez_op: 123 if ((long)regs->regs[insn.mm_i_format.rs] <= 0) 124 *contpc = regs->cp0_epc + 125 dec_insn.pc_inc + 126 (insn.mm_i_format.simmediate << 1); 127 else 128 *contpc = regs->cp0_epc + 129 dec_insn.pc_inc + 130 dec_insn.next_pc_inc; 131 return 1; 132 case mm_bgtz_op: 133 if ((long)regs->regs[insn.mm_i_format.rs] <= 0) 134 *contpc = regs->cp0_epc + 135 dec_insn.pc_inc + 136 (insn.mm_i_format.simmediate << 1); 137 else 138 *contpc = regs->cp0_epc + 139 dec_insn.pc_inc + 140 dec_insn.next_pc_inc; 141 return 1; 142 case mm_bc2f_op: 143 case mm_bc1f_op: 144 bc_false = 1; 145 /* Fall through */ 146 case mm_bc2t_op: 147 case mm_bc1t_op: 148 preempt_disable(); 149 if (is_fpu_owner()) 150 fcr31 = read_32bit_cp1_register(CP1_STATUS); 151 else 152 fcr31 = current->thread.fpu.fcr31; 153 preempt_enable(); 154 155 if (bc_false) 156 fcr31 = ~fcr31; 157 158 bit = (insn.mm_i_format.rs >> 2); 159 bit += (bit != 0); 160 bit += 23; 161 if (fcr31 & (1 << bit)) 162 *contpc = regs->cp0_epc + 163 dec_insn.pc_inc + 164 (insn.mm_i_format.simmediate << 1); 165 else 166 *contpc = regs->cp0_epc + 167 dec_insn.pc_inc + dec_insn.next_pc_inc; 168 return 1; 169 } 170 break; 171 case mm_pool16c_op: 172 switch (insn.mm_i_format.rt) { 173 case mm_jalr16_op: 174 case mm_jalrs16_op: 175 regs->regs[31] = regs->cp0_epc + 176 dec_insn.pc_inc + dec_insn.next_pc_inc; 177 /* Fall through */ 178 case mm_jr16_op: 179 *contpc = regs->regs[insn.mm_i_format.rs]; 180 return 1; 181 } 182 break; 183 case mm_beqz16_op: 184 if ((long)regs->regs[reg16to32map[insn.mm_b1_format.rs]] == 0) 185 *contpc = regs->cp0_epc + 186 dec_insn.pc_inc + 187 (insn.mm_b1_format.simmediate << 1); 188 else 189 *contpc = regs->cp0_epc + 190 dec_insn.pc_inc + dec_insn.next_pc_inc; 191 return 1; 192 case mm_bnez16_op: 193 if ((long)regs->regs[reg16to32map[insn.mm_b1_format.rs]] != 0) 194 *contpc = regs->cp0_epc + 195 dec_insn.pc_inc + 196 (insn.mm_b1_format.simmediate << 1); 197 else 198 *contpc = regs->cp0_epc + 199 dec_insn.pc_inc + dec_insn.next_pc_inc; 200 return 1; 201 case mm_b16_op: 202 *contpc = regs->cp0_epc + dec_insn.pc_inc + 203 (insn.mm_b0_format.simmediate << 1); 204 return 1; 205 case mm_beq32_op: 206 if (regs->regs[insn.mm_i_format.rs] == 207 regs->regs[insn.mm_i_format.rt]) 208 *contpc = regs->cp0_epc + 209 dec_insn.pc_inc + 210 (insn.mm_i_format.simmediate << 1); 211 else 212 *contpc = regs->cp0_epc + 213 dec_insn.pc_inc + 214 dec_insn.next_pc_inc; 215 return 1; 216 case mm_bne32_op: 217 if (regs->regs[insn.mm_i_format.rs] != 218 regs->regs[insn.mm_i_format.rt]) 219 *contpc = regs->cp0_epc + 220 dec_insn.pc_inc + 221 (insn.mm_i_format.simmediate << 1); 222 else 223 *contpc = regs->cp0_epc + 224 dec_insn.pc_inc + dec_insn.next_pc_inc; 225 return 1; 226 case mm_jalx32_op: 227 regs->regs[31] = regs->cp0_epc + 228 dec_insn.pc_inc + dec_insn.next_pc_inc; 229 *contpc = regs->cp0_epc + dec_insn.pc_inc; 230 *contpc >>= 28; 231 *contpc <<= 28; 232 *contpc |= (insn.j_format.target << 2); 233 return 1; 234 case mm_jals32_op: 235 case mm_jal32_op: 236 regs->regs[31] = regs->cp0_epc + 237 dec_insn.pc_inc + dec_insn.next_pc_inc; 238 /* Fall through */ 239 case mm_j32_op: 240 *contpc = regs->cp0_epc + dec_insn.pc_inc; 241 *contpc >>= 27; 242 *contpc <<= 27; 243 *contpc |= (insn.j_format.target << 1); 244 set_isa16_mode(*contpc); 245 return 1; 246 } 247 return 0; 248 } 249 250 /* 251 * Compute return address and emulate branch in microMIPS mode after an 252 * exception only. It does not handle compact branches/jumps and cannot 253 * be used in interrupt context. (Compact branches/jumps do not cause 254 * exceptions.) 255 */ 256 int __microMIPS_compute_return_epc(struct pt_regs *regs) 257 { 258 u16 __user *pc16; 259 u16 halfword; 260 unsigned int word; 261 unsigned long contpc; 262 struct mm_decoded_insn mminsn = { 0 }; 263 264 mminsn.micro_mips_mode = 1; 265 266 /* This load never faults. */ 267 pc16 = (unsigned short __user *)msk_isa16_mode(regs->cp0_epc); 268 __get_user(halfword, pc16); 269 pc16++; 270 contpc = regs->cp0_epc + 2; 271 word = ((unsigned int)halfword << 16); 272 mminsn.pc_inc = 2; 273 274 if (!mm_insn_16bit(halfword)) { 275 __get_user(halfword, pc16); 276 pc16++; 277 contpc = regs->cp0_epc + 4; 278 mminsn.pc_inc = 4; 279 word |= halfword; 280 } 281 mminsn.insn = word; 282 283 if (get_user(halfword, pc16)) 284 goto sigsegv; 285 mminsn.next_pc_inc = 2; 286 word = ((unsigned int)halfword << 16); 287 288 if (!mm_insn_16bit(halfword)) { 289 pc16++; 290 if (get_user(halfword, pc16)) 291 goto sigsegv; 292 mminsn.next_pc_inc = 4; 293 word |= halfword; 294 } 295 mminsn.next_insn = word; 296 297 mm_isBranchInstr(regs, mminsn, &contpc); 298 299 regs->cp0_epc = contpc; 300 301 return 0; 302 303 sigsegv: 304 force_sig(SIGSEGV, current); 305 return -EFAULT; 306 } 307 308 /* 309 * Compute return address and emulate branch in MIPS16e mode after an 310 * exception only. It does not handle compact branches/jumps and cannot 311 * be used in interrupt context. (Compact branches/jumps do not cause 312 * exceptions.) 313 */ 314 int __MIPS16e_compute_return_epc(struct pt_regs *regs) 315 { 316 u16 __user *addr; 317 union mips16e_instruction inst; 318 u16 inst2; 319 u32 fullinst; 320 long epc; 321 322 epc = regs->cp0_epc; 323 324 /* Read the instruction. */ 325 addr = (u16 __user *)msk_isa16_mode(epc); 326 if (__get_user(inst.full, addr)) { 327 force_sig(SIGSEGV, current); 328 return -EFAULT; 329 } 330 331 switch (inst.ri.opcode) { 332 case MIPS16e_extend_op: 333 regs->cp0_epc += 4; 334 return 0; 335 336 /* 337 * JAL and JALX in MIPS16e mode 338 */ 339 case MIPS16e_jal_op: 340 addr += 1; 341 if (__get_user(inst2, addr)) { 342 force_sig(SIGSEGV, current); 343 return -EFAULT; 344 } 345 fullinst = ((unsigned)inst.full << 16) | inst2; 346 regs->regs[31] = epc + 6; 347 epc += 4; 348 epc >>= 28; 349 epc <<= 28; 350 /* 351 * JAL:5 X:1 TARGET[20-16]:5 TARGET[25:21]:5 TARGET[15:0]:16 352 * 353 * ......TARGET[15:0].................TARGET[20:16]........... 354 * ......TARGET[25:21] 355 */ 356 epc |= 357 ((fullinst & 0xffff) << 2) | ((fullinst & 0x3e00000) >> 3) | 358 ((fullinst & 0x1f0000) << 7); 359 if (!inst.jal.x) 360 set_isa16_mode(epc); /* Set ISA mode bit. */ 361 regs->cp0_epc = epc; 362 return 0; 363 364 /* 365 * J(AL)R(C) 366 */ 367 case MIPS16e_rr_op: 368 if (inst.rr.func == MIPS16e_jr_func) { 369 370 if (inst.rr.ra) 371 regs->cp0_epc = regs->regs[31]; 372 else 373 regs->cp0_epc = 374 regs->regs[reg16to32[inst.rr.rx]]; 375 376 if (inst.rr.l) { 377 if (inst.rr.nd) 378 regs->regs[31] = epc + 2; 379 else 380 regs->regs[31] = epc + 4; 381 } 382 return 0; 383 } 384 break; 385 } 386 387 /* 388 * All other cases have no branch delay slot and are 16-bits. 389 * Branches do not cause an exception. 390 */ 391 regs->cp0_epc += 2; 392 393 return 0; 394 } 395 396 /** 397 * __compute_return_epc_for_insn - Computes the return address and do emulate 398 * branch simulation, if required. 399 * 400 * @regs: Pointer to pt_regs 401 * @insn: branch instruction to decode 402 * @returns: -EFAULT on error and forces SIGBUS, and on success 403 * returns 0 or BRANCH_LIKELY_TAKEN as appropriate after 404 * evaluating the branch. 405 * 406 * MIPS R6 Compact branches and forbidden slots: 407 * Compact branches do not throw exceptions because they do 408 * not have delay slots. The forbidden slot instruction ($PC+4) 409 * is only executed if the branch was not taken. Otherwise the 410 * forbidden slot is skipped entirely. This means that the 411 * only possible reason to be here because of a MIPS R6 compact 412 * branch instruction is that the forbidden slot has thrown one. 413 * In that case the branch was not taken, so the EPC can be safely 414 * set to EPC + 8. 415 */ 416 int __compute_return_epc_for_insn(struct pt_regs *regs, 417 union mips_instruction insn) 418 { 419 unsigned int bit, fcr31, dspcontrol, reg; 420 long epc = regs->cp0_epc; 421 int ret = 0; 422 423 switch (insn.i_format.opcode) { 424 /* 425 * jr and jalr are in r_format format. 426 */ 427 case spec_op: 428 switch (insn.r_format.func) { 429 case jalr_op: 430 regs->regs[insn.r_format.rd] = epc + 8; 431 /* Fall through */ 432 case jr_op: 433 if (NO_R6EMU && insn.r_format.func == jr_op) 434 goto sigill_r6; 435 regs->cp0_epc = regs->regs[insn.r_format.rs]; 436 break; 437 } 438 break; 439 440 /* 441 * This group contains: 442 * bltz_op, bgez_op, bltzl_op, bgezl_op, 443 * bltzal_op, bgezal_op, bltzall_op, bgezall_op. 444 */ 445 case bcond_op: 446 switch (insn.i_format.rt) { 447 case bltzl_op: 448 if (NO_R6EMU) 449 goto sigill_r6; 450 case bltz_op: 451 if ((long)regs->regs[insn.i_format.rs] < 0) { 452 epc = epc + 4 + (insn.i_format.simmediate << 2); 453 if (insn.i_format.rt == bltzl_op) 454 ret = BRANCH_LIKELY_TAKEN; 455 } else 456 epc += 8; 457 regs->cp0_epc = epc; 458 break; 459 460 case bgezl_op: 461 if (NO_R6EMU) 462 goto sigill_r6; 463 case bgez_op: 464 if ((long)regs->regs[insn.i_format.rs] >= 0) { 465 epc = epc + 4 + (insn.i_format.simmediate << 2); 466 if (insn.i_format.rt == bgezl_op) 467 ret = BRANCH_LIKELY_TAKEN; 468 } else 469 epc += 8; 470 regs->cp0_epc = epc; 471 break; 472 473 case bltzal_op: 474 case bltzall_op: 475 if (NO_R6EMU && (insn.i_format.rs || 476 insn.i_format.rt == bltzall_op)) { 477 ret = -SIGILL; 478 break; 479 } 480 regs->regs[31] = epc + 8; 481 /* 482 * OK we are here either because we hit a NAL 483 * instruction or because we are emulating an 484 * old bltzal{,l} one. Let's figure out what the 485 * case really is. 486 */ 487 if (!insn.i_format.rs) { 488 /* 489 * NAL or BLTZAL with rs == 0 490 * Doesn't matter if we are R6 or not. The 491 * result is the same 492 */ 493 regs->cp0_epc += 4 + 494 (insn.i_format.simmediate << 2); 495 break; 496 } 497 /* Now do the real thing for non-R6 BLTZAL{,L} */ 498 if ((long)regs->regs[insn.i_format.rs] < 0) { 499 epc = epc + 4 + (insn.i_format.simmediate << 2); 500 if (insn.i_format.rt == bltzall_op) 501 ret = BRANCH_LIKELY_TAKEN; 502 } else 503 epc += 8; 504 regs->cp0_epc = epc; 505 break; 506 507 case bgezal_op: 508 case bgezall_op: 509 if (NO_R6EMU && (insn.i_format.rs || 510 insn.i_format.rt == bgezall_op)) { 511 ret = -SIGILL; 512 break; 513 } 514 regs->regs[31] = epc + 8; 515 /* 516 * OK we are here either because we hit a BAL 517 * instruction or because we are emulating an 518 * old bgezal{,l} one. Let's figure out what the 519 * case really is. 520 */ 521 if (!insn.i_format.rs) { 522 /* 523 * BAL or BGEZAL with rs == 0 524 * Doesn't matter if we are R6 or not. The 525 * result is the same 526 */ 527 regs->cp0_epc += 4 + 528 (insn.i_format.simmediate << 2); 529 break; 530 } 531 /* Now do the real thing for non-R6 BGEZAL{,L} */ 532 if ((long)regs->regs[insn.i_format.rs] >= 0) { 533 epc = epc + 4 + (insn.i_format.simmediate << 2); 534 if (insn.i_format.rt == bgezall_op) 535 ret = BRANCH_LIKELY_TAKEN; 536 } else 537 epc += 8; 538 regs->cp0_epc = epc; 539 break; 540 541 case bposge32_op: 542 if (!cpu_has_dsp) 543 goto sigill_dsp; 544 545 dspcontrol = rddsp(0x01); 546 547 if (dspcontrol >= 32) { 548 epc = epc + 4 + (insn.i_format.simmediate << 2); 549 } else 550 epc += 8; 551 regs->cp0_epc = epc; 552 break; 553 } 554 break; 555 556 /* 557 * These are unconditional and in j_format. 558 */ 559 case jal_op: 560 regs->regs[31] = regs->cp0_epc + 8; 561 case j_op: 562 epc += 4; 563 epc >>= 28; 564 epc <<= 28; 565 epc |= (insn.j_format.target << 2); 566 regs->cp0_epc = epc; 567 if (insn.i_format.opcode == jalx_op) 568 set_isa16_mode(regs->cp0_epc); 569 break; 570 571 /* 572 * These are conditional and in i_format. 573 */ 574 case beql_op: 575 if (NO_R6EMU) 576 goto sigill_r6; 577 case beq_op: 578 if (regs->regs[insn.i_format.rs] == 579 regs->regs[insn.i_format.rt]) { 580 epc = epc + 4 + (insn.i_format.simmediate << 2); 581 if (insn.i_format.opcode == beql_op) 582 ret = BRANCH_LIKELY_TAKEN; 583 } else 584 epc += 8; 585 regs->cp0_epc = epc; 586 break; 587 588 case bnel_op: 589 if (NO_R6EMU) 590 goto sigill_r6; 591 case bne_op: 592 if (regs->regs[insn.i_format.rs] != 593 regs->regs[insn.i_format.rt]) { 594 epc = epc + 4 + (insn.i_format.simmediate << 2); 595 if (insn.i_format.opcode == bnel_op) 596 ret = BRANCH_LIKELY_TAKEN; 597 } else 598 epc += 8; 599 regs->cp0_epc = epc; 600 break; 601 602 case blezl_op: /* not really i_format */ 603 if (!insn.i_format.rt && NO_R6EMU) 604 goto sigill_r6; 605 case blez_op: 606 /* 607 * Compact branches for R6 for the 608 * blez and blezl opcodes. 609 * BLEZ | rs = 0 | rt != 0 == BLEZALC 610 * BLEZ | rs = rt != 0 == BGEZALC 611 * BLEZ | rs != 0 | rt != 0 == BGEUC 612 * BLEZL | rs = 0 | rt != 0 == BLEZC 613 * BLEZL | rs = rt != 0 == BGEZC 614 * BLEZL | rs != 0 | rt != 0 == BGEC 615 * 616 * For real BLEZ{,L}, rt is always 0. 617 */ 618 619 if (cpu_has_mips_r6 && insn.i_format.rt) { 620 if ((insn.i_format.opcode == blez_op) && 621 ((!insn.i_format.rs && insn.i_format.rt) || 622 (insn.i_format.rs == insn.i_format.rt))) 623 regs->regs[31] = epc + 4; 624 regs->cp0_epc += 8; 625 break; 626 } 627 /* rt field assumed to be zero */ 628 if ((long)regs->regs[insn.i_format.rs] <= 0) { 629 epc = epc + 4 + (insn.i_format.simmediate << 2); 630 if (insn.i_format.opcode == blezl_op) 631 ret = BRANCH_LIKELY_TAKEN; 632 } else 633 epc += 8; 634 regs->cp0_epc = epc; 635 break; 636 637 case bgtzl_op: 638 if (!insn.i_format.rt && NO_R6EMU) 639 goto sigill_r6; 640 case bgtz_op: 641 /* 642 * Compact branches for R6 for the 643 * bgtz and bgtzl opcodes. 644 * BGTZ | rs = 0 | rt != 0 == BGTZALC 645 * BGTZ | rs = rt != 0 == BLTZALC 646 * BGTZ | rs != 0 | rt != 0 == BLTUC 647 * BGTZL | rs = 0 | rt != 0 == BGTZC 648 * BGTZL | rs = rt != 0 == BLTZC 649 * BGTZL | rs != 0 | rt != 0 == BLTC 650 * 651 * *ZALC varint for BGTZ &&& rt != 0 652 * For real GTZ{,L}, rt is always 0. 653 */ 654 if (cpu_has_mips_r6 && insn.i_format.rt) { 655 if ((insn.i_format.opcode == blez_op) && 656 ((!insn.i_format.rs && insn.i_format.rt) || 657 (insn.i_format.rs == insn.i_format.rt))) 658 regs->regs[31] = epc + 4; 659 regs->cp0_epc += 8; 660 break; 661 } 662 663 /* rt field assumed to be zero */ 664 if ((long)regs->regs[insn.i_format.rs] > 0) { 665 epc = epc + 4 + (insn.i_format.simmediate << 2); 666 if (insn.i_format.opcode == bgtzl_op) 667 ret = BRANCH_LIKELY_TAKEN; 668 } else 669 epc += 8; 670 regs->cp0_epc = epc; 671 break; 672 673 /* 674 * And now the FPA/cp1 branch instructions. 675 */ 676 case cop1_op: 677 if (cpu_has_mips_r6 && 678 ((insn.i_format.rs == bc1eqz_op) || 679 (insn.i_format.rs == bc1nez_op))) { 680 if (!used_math()) { /* First time FPU user */ 681 ret = init_fpu(); 682 if (ret && NO_R6EMU) { 683 ret = -ret; 684 break; 685 } 686 ret = 0; 687 set_used_math(); 688 } 689 lose_fpu(1); /* Save FPU state for the emulator. */ 690 reg = insn.i_format.rt; 691 bit = get_fpr32(¤t->thread.fpu.fpr[reg], 0) & 0x1; 692 if (insn.i_format.rs == bc1eqz_op) 693 bit = !bit; 694 own_fpu(1); 695 if (bit) 696 epc = epc + 4 + 697 (insn.i_format.simmediate << 2); 698 else 699 epc += 8; 700 regs->cp0_epc = epc; 701 702 break; 703 } else { 704 705 preempt_disable(); 706 if (is_fpu_owner()) 707 fcr31 = read_32bit_cp1_register(CP1_STATUS); 708 else 709 fcr31 = current->thread.fpu.fcr31; 710 preempt_enable(); 711 712 bit = (insn.i_format.rt >> 2); 713 bit += (bit != 0); 714 bit += 23; 715 switch (insn.i_format.rt & 3) { 716 case 0: /* bc1f */ 717 case 2: /* bc1fl */ 718 if (~fcr31 & (1 << bit)) { 719 epc = epc + 4 + 720 (insn.i_format.simmediate << 2); 721 if (insn.i_format.rt == 2) 722 ret = BRANCH_LIKELY_TAKEN; 723 } else 724 epc += 8; 725 regs->cp0_epc = epc; 726 break; 727 728 case 1: /* bc1t */ 729 case 3: /* bc1tl */ 730 if (fcr31 & (1 << bit)) { 731 epc = epc + 4 + 732 (insn.i_format.simmediate << 2); 733 if (insn.i_format.rt == 3) 734 ret = BRANCH_LIKELY_TAKEN; 735 } else 736 epc += 8; 737 regs->cp0_epc = epc; 738 break; 739 } 740 break; 741 } 742 #ifdef CONFIG_CPU_CAVIUM_OCTEON 743 case lwc2_op: /* This is bbit0 on Octeon */ 744 if ((regs->regs[insn.i_format.rs] & (1ull<<insn.i_format.rt)) 745 == 0) 746 epc = epc + 4 + (insn.i_format.simmediate << 2); 747 else 748 epc += 8; 749 regs->cp0_epc = epc; 750 break; 751 case ldc2_op: /* This is bbit032 on Octeon */ 752 if ((regs->regs[insn.i_format.rs] & 753 (1ull<<(insn.i_format.rt+32))) == 0) 754 epc = epc + 4 + (insn.i_format.simmediate << 2); 755 else 756 epc += 8; 757 regs->cp0_epc = epc; 758 break; 759 case swc2_op: /* This is bbit1 on Octeon */ 760 if (regs->regs[insn.i_format.rs] & (1ull<<insn.i_format.rt)) 761 epc = epc + 4 + (insn.i_format.simmediate << 2); 762 else 763 epc += 8; 764 regs->cp0_epc = epc; 765 break; 766 case sdc2_op: /* This is bbit132 on Octeon */ 767 if (regs->regs[insn.i_format.rs] & 768 (1ull<<(insn.i_format.rt+32))) 769 epc = epc + 4 + (insn.i_format.simmediate << 2); 770 else 771 epc += 8; 772 regs->cp0_epc = epc; 773 break; 774 #else 775 case bc6_op: 776 /* Only valid for MIPS R6 */ 777 if (!cpu_has_mips_r6) { 778 ret = -SIGILL; 779 break; 780 } 781 regs->cp0_epc += 8; 782 break; 783 case balc6_op: 784 if (!cpu_has_mips_r6) { 785 ret = -SIGILL; 786 break; 787 } 788 /* Compact branch: BALC */ 789 regs->regs[31] = epc + 4; 790 epc += 4 + (insn.i_format.simmediate << 2); 791 regs->cp0_epc = epc; 792 break; 793 case pop66_op: 794 if (!cpu_has_mips_r6) { 795 ret = -SIGILL; 796 break; 797 } 798 /* Compact branch: BEQZC || JIC */ 799 regs->cp0_epc += 8; 800 break; 801 case pop76_op: 802 if (!cpu_has_mips_r6) { 803 ret = -SIGILL; 804 break; 805 } 806 /* Compact branch: BNEZC || JIALC */ 807 if (insn.i_format.rs) 808 regs->regs[31] = epc + 4; 809 regs->cp0_epc += 8; 810 break; 811 #endif 812 case pop10_op: 813 case pop30_op: 814 /* Only valid for MIPS R6 */ 815 if (!cpu_has_mips_r6) { 816 ret = -SIGILL; 817 break; 818 } 819 /* 820 * Compact branches: 821 * bovc, beqc, beqzalc, bnvc, bnec, bnezlac 822 */ 823 if (insn.i_format.rt && !insn.i_format.rs) 824 regs->regs[31] = epc + 4; 825 regs->cp0_epc += 8; 826 break; 827 } 828 829 return ret; 830 831 sigill_dsp: 832 printk("%s: DSP branch but not DSP ASE - sending SIGBUS.\n", current->comm); 833 force_sig(SIGBUS, current); 834 return -EFAULT; 835 sigill_r6: 836 pr_info("%s: R2 branch but r2-to-r6 emulator is not preset - sending SIGILL.\n", 837 current->comm); 838 force_sig(SIGILL, current); 839 return -EFAULT; 840 } 841 EXPORT_SYMBOL_GPL(__compute_return_epc_for_insn); 842 843 int __compute_return_epc(struct pt_regs *regs) 844 { 845 unsigned int __user *addr; 846 long epc; 847 union mips_instruction insn; 848 849 epc = regs->cp0_epc; 850 if (epc & 3) 851 goto unaligned; 852 853 /* 854 * Read the instruction 855 */ 856 addr = (unsigned int __user *) epc; 857 if (__get_user(insn.word, addr)) { 858 force_sig(SIGSEGV, current); 859 return -EFAULT; 860 } 861 862 return __compute_return_epc_for_insn(regs, insn); 863 864 unaligned: 865 printk("%s: unaligned epc - sending SIGBUS.\n", current->comm); 866 force_sig(SIGBUS, current); 867 return -EFAULT; 868 } 869 870 #if (defined CONFIG_KPROBES) || (defined CONFIG_UPROBES) 871 872 int __insn_is_compact_branch(union mips_instruction insn) 873 { 874 if (!cpu_has_mips_r6) 875 return 0; 876 877 switch (insn.i_format.opcode) { 878 case blezl_op: 879 case bgtzl_op: 880 case blez_op: 881 case bgtz_op: 882 /* 883 * blez[l] and bgtz[l] opcodes with non-zero rt 884 * are MIPS R6 compact branches 885 */ 886 if (insn.i_format.rt) 887 return 1; 888 break; 889 case bc6_op: 890 case balc6_op: 891 case pop10_op: 892 case pop30_op: 893 case pop66_op: 894 case pop76_op: 895 return 1; 896 } 897 898 return 0; 899 } 900 EXPORT_SYMBOL_GPL(__insn_is_compact_branch); 901 902 #endif /* CONFIG_KPROBES || CONFIG_UPROBES */ 903