1/* SPDX-License-Identifier: GPL-2.0-or-later */ 2/* 3 * OpenRISC entry.S 4 * 5 * Linux architectural port borrowing liberally from similar works of 6 * others. All original copyrights apply as per the original source 7 * declaration. 8 * 9 * Modifications for the OpenRISC architecture: 10 * Copyright (C) 2003 Matjaz Breskvar <phoenix@bsemi.com> 11 * Copyright (C) 2005 Gyorgy Jeney <nog@bsemi.com> 12 * Copyright (C) 2010-2011 Jonas Bonn <jonas@southpole.se> 13 */ 14 15#include <linux/linkage.h> 16#include <linux/pgtable.h> 17 18#include <asm/processor.h> 19#include <asm/unistd.h> 20#include <asm/thread_info.h> 21#include <asm/errno.h> 22#include <asm/spr_defs.h> 23#include <asm/page.h> 24#include <asm/mmu.h> 25#include <asm/asm-offsets.h> 26 27#define DISABLE_INTERRUPTS(t1,t2) \ 28 l.mfspr t2,r0,SPR_SR ;\ 29 l.movhi t1,hi(~(SPR_SR_IEE|SPR_SR_TEE)) ;\ 30 l.ori t1,t1,lo(~(SPR_SR_IEE|SPR_SR_TEE)) ;\ 31 l.and t2,t2,t1 ;\ 32 l.mtspr r0,t2,SPR_SR 33 34#define ENABLE_INTERRUPTS(t1) \ 35 l.mfspr t1,r0,SPR_SR ;\ 36 l.ori t1,t1,lo(SPR_SR_IEE|SPR_SR_TEE) ;\ 37 l.mtspr r0,t1,SPR_SR 38 39/* =========================================================[ macros ]=== */ 40 41#ifdef CONFIG_TRACE_IRQFLAGS 42/* 43 * Trace irq on/off creating a stack frame. 44 */ 45#define TRACE_IRQS_OP(trace_op) \ 46 l.sw -8(r1),r2 /* store frame pointer */ ;\ 47 l.sw -4(r1),r9 /* store return address */ ;\ 48 l.addi r2,r1,0 /* move sp to fp */ ;\ 49 l.jal trace_op ;\ 50 l.addi r1,r1,-8 ;\ 51 l.ori r1,r2,0 /* restore sp */ ;\ 52 l.lwz r9,-4(r1) /* restore return address */ ;\ 53 l.lwz r2,-8(r1) /* restore fp */ ;\ 54/* 55 * Trace irq on/off and save registers we need that would otherwise be 56 * clobbered. 57 */ 58#define TRACE_IRQS_SAVE(t1,trace_op) \ 59 l.sw -12(r1),t1 /* save extra reg */ ;\ 60 l.sw -8(r1),r2 /* store frame pointer */ ;\ 61 l.sw -4(r1),r9 /* store return address */ ;\ 62 l.addi r2,r1,0 /* move sp to fp */ ;\ 63 l.jal trace_op ;\ 64 l.addi r1,r1,-12 ;\ 65 l.ori r1,r2,0 /* restore sp */ ;\ 66 l.lwz r9,-4(r1) /* restore return address */ ;\ 67 l.lwz r2,-8(r1) /* restore fp */ ;\ 68 l.lwz t1,-12(r1) /* restore extra reg */ 69 70#define TRACE_IRQS_OFF TRACE_IRQS_OP(trace_hardirqs_off) 71#define TRACE_IRQS_ON TRACE_IRQS_OP(trace_hardirqs_on) 72#define TRACE_IRQS_ON_SYSCALL \ 73 TRACE_IRQS_SAVE(r10,trace_hardirqs_on) ;\ 74 l.lwz r3,PT_GPR3(r1) ;\ 75 l.lwz r4,PT_GPR4(r1) ;\ 76 l.lwz r5,PT_GPR5(r1) ;\ 77 l.lwz r6,PT_GPR6(r1) ;\ 78 l.lwz r7,PT_GPR7(r1) ;\ 79 l.lwz r8,PT_GPR8(r1) ;\ 80 l.lwz r11,PT_GPR11(r1) 81#define TRACE_IRQS_OFF_ENTRY \ 82 l.lwz r5,PT_SR(r1) ;\ 83 l.andi r3,r5,(SPR_SR_IEE|SPR_SR_TEE) ;\ 84 l.sfeq r5,r0 /* skip trace if irqs were already off */;\ 85 l.bf 1f ;\ 86 l.nop ;\ 87 TRACE_IRQS_SAVE(r4,trace_hardirqs_off) ;\ 881: 89#else 90#define TRACE_IRQS_OFF 91#define TRACE_IRQS_ON 92#define TRACE_IRQS_OFF_ENTRY 93#define TRACE_IRQS_ON_SYSCALL 94#endif 95 96/* 97 * We need to disable interrupts at beginning of RESTORE_ALL 98 * since interrupt might come in after we've loaded EPC return address 99 * and overwrite EPC with address somewhere in RESTORE_ALL 100 * which is of course wrong! 101 */ 102 103#define RESTORE_ALL \ 104 DISABLE_INTERRUPTS(r3,r4) ;\ 105 l.lwz r3,PT_PC(r1) ;\ 106 l.mtspr r0,r3,SPR_EPCR_BASE ;\ 107 l.lwz r3,PT_SR(r1) ;\ 108 l.mtspr r0,r3,SPR_ESR_BASE ;\ 109 l.lwz r2,PT_GPR2(r1) ;\ 110 l.lwz r3,PT_GPR3(r1) ;\ 111 l.lwz r4,PT_GPR4(r1) ;\ 112 l.lwz r5,PT_GPR5(r1) ;\ 113 l.lwz r6,PT_GPR6(r1) ;\ 114 l.lwz r7,PT_GPR7(r1) ;\ 115 l.lwz r8,PT_GPR8(r1) ;\ 116 l.lwz r9,PT_GPR9(r1) ;\ 117 l.lwz r10,PT_GPR10(r1) ;\ 118 l.lwz r11,PT_GPR11(r1) ;\ 119 l.lwz r12,PT_GPR12(r1) ;\ 120 l.lwz r13,PT_GPR13(r1) ;\ 121 l.lwz r14,PT_GPR14(r1) ;\ 122 l.lwz r15,PT_GPR15(r1) ;\ 123 l.lwz r16,PT_GPR16(r1) ;\ 124 l.lwz r17,PT_GPR17(r1) ;\ 125 l.lwz r18,PT_GPR18(r1) ;\ 126 l.lwz r19,PT_GPR19(r1) ;\ 127 l.lwz r20,PT_GPR20(r1) ;\ 128 l.lwz r21,PT_GPR21(r1) ;\ 129 l.lwz r22,PT_GPR22(r1) ;\ 130 l.lwz r23,PT_GPR23(r1) ;\ 131 l.lwz r24,PT_GPR24(r1) ;\ 132 l.lwz r25,PT_GPR25(r1) ;\ 133 l.lwz r26,PT_GPR26(r1) ;\ 134 l.lwz r27,PT_GPR27(r1) ;\ 135 l.lwz r28,PT_GPR28(r1) ;\ 136 l.lwz r29,PT_GPR29(r1) ;\ 137 l.lwz r30,PT_GPR30(r1) ;\ 138 l.lwz r31,PT_GPR31(r1) ;\ 139 l.lwz r1,PT_SP(r1) ;\ 140 l.rfe 141 142 143#define EXCEPTION_ENTRY(handler) \ 144 .global handler ;\ 145handler: ;\ 146 /* r1, EPCR, ESR a already saved */ ;\ 147 l.sw PT_GPR2(r1),r2 ;\ 148 l.sw PT_GPR3(r1),r3 ;\ 149 /* r4 already save */ ;\ 150 l.sw PT_GPR5(r1),r5 ;\ 151 l.sw PT_GPR6(r1),r6 ;\ 152 l.sw PT_GPR7(r1),r7 ;\ 153 l.sw PT_GPR8(r1),r8 ;\ 154 l.sw PT_GPR9(r1),r9 ;\ 155 /* r10 already saved */ ;\ 156 l.sw PT_GPR11(r1),r11 ;\ 157 /* r12 already saved */ ;\ 158 l.sw PT_GPR13(r1),r13 ;\ 159 l.sw PT_GPR14(r1),r14 ;\ 160 l.sw PT_GPR15(r1),r15 ;\ 161 l.sw PT_GPR16(r1),r16 ;\ 162 l.sw PT_GPR17(r1),r17 ;\ 163 l.sw PT_GPR18(r1),r18 ;\ 164 l.sw PT_GPR19(r1),r19 ;\ 165 l.sw PT_GPR20(r1),r20 ;\ 166 l.sw PT_GPR21(r1),r21 ;\ 167 l.sw PT_GPR22(r1),r22 ;\ 168 l.sw PT_GPR23(r1),r23 ;\ 169 l.sw PT_GPR24(r1),r24 ;\ 170 l.sw PT_GPR25(r1),r25 ;\ 171 l.sw PT_GPR26(r1),r26 ;\ 172 l.sw PT_GPR27(r1),r27 ;\ 173 l.sw PT_GPR28(r1),r28 ;\ 174 l.sw PT_GPR29(r1),r29 ;\ 175 /* r30 already save */ ;\ 176 l.sw PT_GPR31(r1),r31 ;\ 177 TRACE_IRQS_OFF_ENTRY ;\ 178 /* Store -1 in orig_gpr11 for non-syscall exceptions */ ;\ 179 l.addi r30,r0,-1 ;\ 180 l.sw PT_ORIG_GPR11(r1),r30 181 182#define UNHANDLED_EXCEPTION(handler,vector) \ 183 .global handler ;\ 184handler: ;\ 185 /* r1, EPCR, ESR already saved */ ;\ 186 l.sw PT_GPR2(r1),r2 ;\ 187 l.sw PT_GPR3(r1),r3 ;\ 188 l.sw PT_GPR5(r1),r5 ;\ 189 l.sw PT_GPR6(r1),r6 ;\ 190 l.sw PT_GPR7(r1),r7 ;\ 191 l.sw PT_GPR8(r1),r8 ;\ 192 l.sw PT_GPR9(r1),r9 ;\ 193 /* r10 already saved */ ;\ 194 l.sw PT_GPR11(r1),r11 ;\ 195 /* r12 already saved */ ;\ 196 l.sw PT_GPR13(r1),r13 ;\ 197 l.sw PT_GPR14(r1),r14 ;\ 198 l.sw PT_GPR15(r1),r15 ;\ 199 l.sw PT_GPR16(r1),r16 ;\ 200 l.sw PT_GPR17(r1),r17 ;\ 201 l.sw PT_GPR18(r1),r18 ;\ 202 l.sw PT_GPR19(r1),r19 ;\ 203 l.sw PT_GPR20(r1),r20 ;\ 204 l.sw PT_GPR21(r1),r21 ;\ 205 l.sw PT_GPR22(r1),r22 ;\ 206 l.sw PT_GPR23(r1),r23 ;\ 207 l.sw PT_GPR24(r1),r24 ;\ 208 l.sw PT_GPR25(r1),r25 ;\ 209 l.sw PT_GPR26(r1),r26 ;\ 210 l.sw PT_GPR27(r1),r27 ;\ 211 l.sw PT_GPR28(r1),r28 ;\ 212 l.sw PT_GPR29(r1),r29 ;\ 213 /* r30 already saved */ ;\ 214 l.sw PT_GPR31(r1),r31 ;\ 215 /* Store -1 in orig_gpr11 for non-syscall exceptions */ ;\ 216 l.addi r30,r0,-1 ;\ 217 l.sw PT_ORIG_GPR11(r1),r30 ;\ 218 l.addi r3,r1,0 ;\ 219 /* r4 is exception EA */ ;\ 220 l.addi r5,r0,vector ;\ 221 l.jal unhandled_exception ;\ 222 l.nop ;\ 223 l.j _ret_from_exception ;\ 224 l.nop 225 226/* clobbers 'reg' */ 227#define CLEAR_LWA_FLAG(reg) \ 228 l.movhi reg,hi(lwa_flag) ;\ 229 l.ori reg,reg,lo(lwa_flag) ;\ 230 l.sw 0(reg),r0 231/* 232 * NOTE: one should never assume that SPR_EPC, SPR_ESR, SPR_EEAR 233 * contain the same values as when exception we're handling 234 * occured. in fact they never do. if you need them use 235 * values saved on stack (for SPR_EPC, SPR_ESR) or content 236 * of r4 (for SPR_EEAR). for details look at EXCEPTION_HANDLE() 237 * in 'arch/openrisc/kernel/head.S' 238 */ 239 240/* =====================================================[ exceptions] === */ 241 242/* ---[ 0x100: RESET exception ]----------------------------------------- */ 243 244EXCEPTION_ENTRY(_tng_kernel_start) 245 l.jal _start 246 l.andi r0,r0,0 247 248/* ---[ 0x200: BUS exception ]------------------------------------------- */ 249 250EXCEPTION_ENTRY(_bus_fault_handler) 251 CLEAR_LWA_FLAG(r3) 252 /* r4: EA of fault (set by EXCEPTION_HANDLE) */ 253 l.jal do_bus_fault 254 l.addi r3,r1,0 /* pt_regs */ 255 256 l.j _ret_from_exception 257 l.nop 258 259/* ---[ 0x300: Data Page Fault exception ]------------------------------- */ 260EXCEPTION_ENTRY(_dtlb_miss_page_fault_handler) 261 CLEAR_LWA_FLAG(r3) 262 l.and r5,r5,r0 263 l.j 1f 264 l.nop 265 266EXCEPTION_ENTRY(_data_page_fault_handler) 267 CLEAR_LWA_FLAG(r3) 268 /* set up parameters for do_page_fault */ 269 l.ori r5,r0,0x300 // exception vector 2701: 271 l.addi r3,r1,0 // pt_regs 272 /* r4 set be EXCEPTION_HANDLE */ // effective address of fault 273 274#ifdef CONFIG_OPENRISC_NO_SPR_SR_DSX 275 l.lwz r6,PT_PC(r3) // address of an offending insn 276 l.lwz r6,0(r6) // instruction that caused pf 277 278 l.srli r6,r6,26 // check opcode for jump insn 279 l.sfeqi r6,0 // l.j 280 l.bf 8f 281 l.sfeqi r6,1 // l.jal 282 l.bf 8f 283 l.sfeqi r6,3 // l.bnf 284 l.bf 8f 285 l.sfeqi r6,4 // l.bf 286 l.bf 8f 287 l.sfeqi r6,0x11 // l.jr 288 l.bf 8f 289 l.sfeqi r6,0x12 // l.jalr 290 l.bf 8f 291 l.nop 292 293 l.j 9f 294 l.nop 295 2968: // offending insn is in delay slot 297 l.lwz r6,PT_PC(r3) // address of an offending insn 298 l.addi r6,r6,4 299 l.lwz r6,0(r6) // instruction that caused pf 300 l.srli r6,r6,26 // get opcode 3019: // offending instruction opcode loaded in r6 302 303#else 304 305 l.mfspr r6,r0,SPR_SR // SR 306 l.andi r6,r6,SPR_SR_DSX // check for delay slot exception 307 l.sfne r6,r0 // exception happened in delay slot 308 l.bnf 7f 309 l.lwz r6,PT_PC(r3) // address of an offending insn 310 311 l.addi r6,r6,4 // offending insn is in delay slot 3127: 313 l.lwz r6,0(r6) // instruction that caused pf 314 l.srli r6,r6,26 // check opcode for write access 315#endif 316 317 l.sfgeui r6,0x33 // check opcode for write access 318 l.bnf 1f 319 l.sfleui r6,0x37 320 l.bnf 1f 321 l.ori r6,r0,0x1 // write access 322 l.j 2f 323 l.nop 3241: l.ori r6,r0,0x0 // !write access 3252: 326 327 /* call fault.c handler in openrisc/mm/fault.c */ 328 l.jal do_page_fault 329 l.nop 330 l.j _ret_from_exception 331 l.nop 332 333/* ---[ 0x400: Insn Page Fault exception ]------------------------------- */ 334EXCEPTION_ENTRY(_itlb_miss_page_fault_handler) 335 CLEAR_LWA_FLAG(r3) 336 l.and r5,r5,r0 337 l.j 1f 338 l.nop 339 340EXCEPTION_ENTRY(_insn_page_fault_handler) 341 CLEAR_LWA_FLAG(r3) 342 /* set up parameters for do_page_fault */ 343 l.ori r5,r0,0x400 // exception vector 3441: 345 l.addi r3,r1,0 // pt_regs 346 /* r4 set be EXCEPTION_HANDLE */ // effective address of fault 347 l.ori r6,r0,0x0 // !write access 348 349 /* call fault.c handler in openrisc/mm/fault.c */ 350 l.jal do_page_fault 351 l.nop 352 l.j _ret_from_exception 353 l.nop 354 355 356/* ---[ 0x500: Timer exception ]----------------------------------------- */ 357 358EXCEPTION_ENTRY(_timer_handler) 359 CLEAR_LWA_FLAG(r3) 360 l.jal timer_interrupt 361 l.addi r3,r1,0 /* pt_regs */ 362 363 l.j _ret_from_intr 364 l.nop 365 366/* ---[ 0x600: Alignment exception ]-------------------------------------- */ 367 368EXCEPTION_ENTRY(_alignment_handler) 369 CLEAR_LWA_FLAG(r3) 370 /* r4: EA of fault (set by EXCEPTION_HANDLE) */ 371 l.jal do_unaligned_access 372 l.addi r3,r1,0 /* pt_regs */ 373 374 l.j _ret_from_exception 375 l.nop 376 377#if 0 378EXCEPTION_ENTRY(_alignment_handler) 379// l.mfspr r2,r0,SPR_EEAR_BASE /* Load the effective address */ 380 l.addi r2,r4,0 381// l.mfspr r5,r0,SPR_EPCR_BASE /* Load the insn address */ 382 l.lwz r5,PT_PC(r1) 383 384 l.lwz r3,0(r5) /* Load insn */ 385 l.srli r4,r3,26 /* Shift left to get the insn opcode */ 386 387 l.sfeqi r4,0x00 /* Check if the load/store insn is in delay slot */ 388 l.bf jmp 389 l.sfeqi r4,0x01 390 l.bf jmp 391 l.sfeqi r4,0x03 392 l.bf jmp 393 l.sfeqi r4,0x04 394 l.bf jmp 395 l.sfeqi r4,0x11 396 l.bf jr 397 l.sfeqi r4,0x12 398 l.bf jr 399 l.nop 400 l.j 1f 401 l.addi r5,r5,4 /* Increment PC to get return insn address */ 402 403jmp: 404 l.slli r4,r3,6 /* Get the signed extended jump length */ 405 l.srai r4,r4,4 406 407 l.lwz r3,4(r5) /* Load the real load/store insn */ 408 409 l.add r5,r5,r4 /* Calculate jump target address */ 410 411 l.j 1f 412 l.srli r4,r3,26 /* Shift left to get the insn opcode */ 413 414jr: 415 l.slli r4,r3,9 /* Shift to get the reg nb */ 416 l.andi r4,r4,0x7c 417 418 l.lwz r3,4(r5) /* Load the real load/store insn */ 419 420 l.add r4,r4,r1 /* Load the jump register value from the stack */ 421 l.lwz r5,0(r4) 422 423 l.srli r4,r3,26 /* Shift left to get the insn opcode */ 424 425 4261: 427// l.mtspr r0,r5,SPR_EPCR_BASE 428 l.sw PT_PC(r1),r5 429 430 l.sfeqi r4,0x26 431 l.bf lhs 432 l.sfeqi r4,0x25 433 l.bf lhz 434 l.sfeqi r4,0x22 435 l.bf lws 436 l.sfeqi r4,0x21 437 l.bf lwz 438 l.sfeqi r4,0x37 439 l.bf sh 440 l.sfeqi r4,0x35 441 l.bf sw 442 l.nop 443 4441: l.j 1b /* I don't know what to do */ 445 l.nop 446 447lhs: l.lbs r5,0(r2) 448 l.slli r5,r5,8 449 l.lbz r6,1(r2) 450 l.or r5,r5,r6 451 l.srli r4,r3,19 452 l.andi r4,r4,0x7c 453 l.add r4,r4,r1 454 l.j align_end 455 l.sw 0(r4),r5 456 457lhz: l.lbz r5,0(r2) 458 l.slli r5,r5,8 459 l.lbz r6,1(r2) 460 l.or r5,r5,r6 461 l.srli r4,r3,19 462 l.andi r4,r4,0x7c 463 l.add r4,r4,r1 464 l.j align_end 465 l.sw 0(r4),r5 466 467lws: l.lbs r5,0(r2) 468 l.slli r5,r5,24 469 l.lbz r6,1(r2) 470 l.slli r6,r6,16 471 l.or r5,r5,r6 472 l.lbz r6,2(r2) 473 l.slli r6,r6,8 474 l.or r5,r5,r6 475 l.lbz r6,3(r2) 476 l.or r5,r5,r6 477 l.srli r4,r3,19 478 l.andi r4,r4,0x7c 479 l.add r4,r4,r1 480 l.j align_end 481 l.sw 0(r4),r5 482 483lwz: l.lbz r5,0(r2) 484 l.slli r5,r5,24 485 l.lbz r6,1(r2) 486 l.slli r6,r6,16 487 l.or r5,r5,r6 488 l.lbz r6,2(r2) 489 l.slli r6,r6,8 490 l.or r5,r5,r6 491 l.lbz r6,3(r2) 492 l.or r5,r5,r6 493 l.srli r4,r3,19 494 l.andi r4,r4,0x7c 495 l.add r4,r4,r1 496 l.j align_end 497 l.sw 0(r4),r5 498 499sh: 500 l.srli r4,r3,9 501 l.andi r4,r4,0x7c 502 l.add r4,r4,r1 503 l.lwz r5,0(r4) 504 l.sb 1(r2),r5 505 l.srli r5,r5,8 506 l.j align_end 507 l.sb 0(r2),r5 508 509sw: 510 l.srli r4,r3,9 511 l.andi r4,r4,0x7c 512 l.add r4,r4,r1 513 l.lwz r5,0(r4) 514 l.sb 3(r2),r5 515 l.srli r5,r5,8 516 l.sb 2(r2),r5 517 l.srli r5,r5,8 518 l.sb 1(r2),r5 519 l.srli r5,r5,8 520 l.j align_end 521 l.sb 0(r2),r5 522 523align_end: 524 l.j _ret_from_intr 525 l.nop 526#endif 527 528/* ---[ 0x700: Illegal insn exception ]---------------------------------- */ 529 530EXCEPTION_ENTRY(_illegal_instruction_handler) 531 /* r4: EA of fault (set by EXCEPTION_HANDLE) */ 532 l.jal do_illegal_instruction 533 l.addi r3,r1,0 /* pt_regs */ 534 535 l.j _ret_from_exception 536 l.nop 537 538/* ---[ 0x800: External interrupt exception ]---------------------------- */ 539 540EXCEPTION_ENTRY(_external_irq_handler) 541#ifdef CONFIG_OPENRISC_ESR_EXCEPTION_BUG_CHECK 542 l.lwz r4,PT_SR(r1) // were interrupts enabled ? 543 l.andi r4,r4,SPR_SR_IEE 544 l.sfeqi r4,0 545 l.bnf 1f // ext irq enabled, all ok. 546 l.nop 547 548#ifdef CONFIG_PRINTK 549 l.addi r1,r1,-0x8 550 l.movhi r3,hi(42f) 551 l.ori r3,r3,lo(42f) 552 l.sw 0x0(r1),r3 553 l.jal _printk 554 l.sw 0x4(r1),r4 555 l.addi r1,r1,0x8 556 557 .section .rodata, "a" 55842: 559 .string "\n\rESR interrupt bug: in _external_irq_handler (ESR %x)\n\r" 560 .align 4 561 .previous 562#endif 563 564 l.ori r4,r4,SPR_SR_IEE // fix the bug 565// l.sw PT_SR(r1),r4 5661: 567#endif 568 CLEAR_LWA_FLAG(r3) 569 l.addi r3,r1,0 570 l.movhi r8,hi(generic_handle_arch_irq) 571 l.ori r8,r8,lo(generic_handle_arch_irq) 572 l.jalr r8 573 l.nop 574 l.j _ret_from_intr 575 l.nop 576 577/* ---[ 0x900: DTLB miss exception ]------------------------------------- */ 578 579 580/* ---[ 0xa00: ITLB miss exception ]------------------------------------- */ 581 582 583/* ---[ 0xb00: Range exception ]----------------------------------------- */ 584 585UNHANDLED_EXCEPTION(_vector_0xb00,0xb00) 586 587/* ---[ 0xc00: Syscall exception ]--------------------------------------- */ 588 589/* 590 * Syscalls are a special type of exception in that they are 591 * _explicitly_ invoked by userspace and can therefore be 592 * held to conform to the same ABI as normal functions with 593 * respect to whether registers are preserved across the call 594 * or not. 595 */ 596 597/* Upon syscall entry we just save the callee-saved registers 598 * and not the call-clobbered ones. 599 */ 600 601_string_syscall_return: 602 .string "syscall r9:0x%08x -> syscall(%ld) return %ld\0" 603 .align 4 604 605ENTRY(_sys_call_handler) 606 /* r1, EPCR, ESR a already saved */ 607 l.sw PT_GPR2(r1),r2 608 /* r3-r8 must be saved because syscall restart relies 609 * on us being able to restart the syscall args... technically 610 * they should be clobbered, otherwise 611 */ 612 l.sw PT_GPR3(r1),r3 613 /* 614 * r4 already saved 615 * r4 holds the EEAR address of the fault, use it as screatch reg and 616 * then load the original r4 617 */ 618 CLEAR_LWA_FLAG(r4) 619 l.lwz r4,PT_GPR4(r1) 620 l.sw PT_GPR5(r1),r5 621 l.sw PT_GPR6(r1),r6 622 l.sw PT_GPR7(r1),r7 623 l.sw PT_GPR8(r1),r8 624 l.sw PT_GPR9(r1),r9 625 /* r10 already saved */ 626 l.sw PT_GPR11(r1),r11 627 /* orig_gpr11 must be set for syscalls */ 628 l.sw PT_ORIG_GPR11(r1),r11 629 /* r12,r13 already saved */ 630 631 /* r14-r28 (even) aren't touched by the syscall fast path below 632 * so we don't need to save them. However, the functions that return 633 * to userspace via a call to switch() DO need to save these because 634 * switch() effectively clobbers them... saving these registers for 635 * such functions is handled in their syscall wrappers (see fork, vfork, 636 * and clone, below). 637 638 /* r30 is the only register we clobber in the fast path */ 639 /* r30 already saved */ 640/* l.sw PT_GPR30(r1),r30 */ 641 642_syscall_check_trace_enter: 643 /* syscalls run with interrupts enabled */ 644 TRACE_IRQS_ON_SYSCALL 645 ENABLE_INTERRUPTS(r29) // enable interrupts, r29 is temp 646 647 /* If TIF_SYSCALL_TRACE is set, then we want to do syscall tracing */ 648 l.lwz r30,TI_FLAGS(r10) 649 l.andi r30,r30,_TIF_SYSCALL_TRACE 650 l.sfne r30,r0 651 l.bf _syscall_trace_enter 652 l.nop 653 654_syscall_check: 655 /* Ensure that the syscall number is reasonable */ 656 l.sfgeui r11,__NR_syscalls 657 l.bf _syscall_badsys 658 l.nop 659 660_syscall_call: 661 l.movhi r29,hi(sys_call_table) 662 l.ori r29,r29,lo(sys_call_table) 663 l.slli r11,r11,2 664 l.add r29,r29,r11 665 l.lwz r29,0(r29) 666 667 l.jalr r29 668 l.nop 669 670_syscall_return: 671 /* All syscalls return here... just pay attention to ret_from_fork 672 * which does it in a round-about way. 673 */ 674 l.sw PT_GPR11(r1),r11 // save return value 675 676#if 0 677_syscall_debug: 678 l.movhi r3,hi(_string_syscall_return) 679 l.ori r3,r3,lo(_string_syscall_return) 680 l.ori r27,r0,2 681 l.sw -4(r1),r27 682 l.sw -8(r1),r11 683 l.lwz r29,PT_ORIG_GPR11(r1) 684 l.sw -12(r1),r29 685 l.lwz r29,PT_GPR9(r1) 686 l.sw -16(r1),r29 687 l.movhi r27,hi(_printk) 688 l.ori r27,r27,lo(_printk) 689 l.jalr r27 690 l.addi r1,r1,-16 691 l.addi r1,r1,16 692#endif 693#if 0 694_syscall_show_regs: 695 l.movhi r27,hi(show_registers) 696 l.ori r27,r27,lo(show_registers) 697 l.jalr r27 698 l.or r3,r1,r1 699#endif 700 701_syscall_check_trace_leave: 702 /* r30 is a callee-saved register so this should still hold the 703 * _TIF_SYSCALL_TRACE flag from _syscall_check_trace_enter above... 704 * _syscall_trace_leave expects syscall result to be in pt_regs->r11. 705 */ 706 l.sfne r30,r0 707 l.bf _syscall_trace_leave 708 l.nop 709 710/* This is where the exception-return code begins... interrupts need to be 711 * disabled the rest of the way here because we can't afford to miss any 712 * interrupts that set NEED_RESCHED or SIGNALPENDING... really true? */ 713 714_syscall_check_work: 715 /* Here we need to disable interrupts */ 716 DISABLE_INTERRUPTS(r27,r29) 717 TRACE_IRQS_OFF 718 l.lwz r30,TI_FLAGS(r10) 719 l.andi r30,r30,_TIF_WORK_MASK 720 l.sfne r30,r0 721 722 l.bnf _syscall_resume_userspace 723 l.nop 724 725 /* Work pending follows a different return path, so we need to 726 * make sure that all the call-saved registers get into pt_regs 727 * before branching... 728 */ 729 l.sw PT_GPR14(r1),r14 730 l.sw PT_GPR16(r1),r16 731 l.sw PT_GPR18(r1),r18 732 l.sw PT_GPR20(r1),r20 733 l.sw PT_GPR22(r1),r22 734 l.sw PT_GPR24(r1),r24 735 l.sw PT_GPR26(r1),r26 736 l.sw PT_GPR28(r1),r28 737 738 /* _work_pending needs to be called with interrupts disabled */ 739 l.j _work_pending 740 l.nop 741 742_syscall_resume_userspace: 743// ENABLE_INTERRUPTS(r29) 744 745 746/* This is the hot path for returning to userspace from a syscall. If there's 747 * work to be done and the branch to _work_pending was taken above, then the 748 * return to userspace will be done via the normal exception return path... 749 * that path restores _all_ registers and will overwrite the "clobbered" 750 * registers with whatever garbage is in pt_regs -- that's OK because those 751 * registers are clobbered anyway and because the extra work is insignificant 752 * in the context of the extra work that _work_pending is doing. 753 754/* Once again, syscalls are special and only guarantee to preserve the 755 * same registers as a normal function call */ 756 757/* The assumption here is that the registers r14-r28 (even) are untouched and 758 * don't need to be restored... be sure that that's really the case! 759 */ 760 761/* This is still too much... we should only be restoring what we actually 762 * clobbered... we should even be using 'scratch' (odd) regs above so that 763 * we don't need to restore anything, hardly... 764 */ 765 766 l.lwz r2,PT_GPR2(r1) 767 768 /* Restore args */ 769 /* r3-r8 are technically clobbered, but syscall restart needs these 770 * to be restored... 771 */ 772 l.lwz r3,PT_GPR3(r1) 773 l.lwz r4,PT_GPR4(r1) 774 l.lwz r5,PT_GPR5(r1) 775 l.lwz r6,PT_GPR6(r1) 776 l.lwz r7,PT_GPR7(r1) 777 l.lwz r8,PT_GPR8(r1) 778 779 l.lwz r9,PT_GPR9(r1) 780 l.lwz r10,PT_GPR10(r1) 781 l.lwz r11,PT_GPR11(r1) 782 783 /* r30 is the only register we clobber in the fast path */ 784 l.lwz r30,PT_GPR30(r1) 785 786 /* Here we use r13-r19 (odd) as scratch regs */ 787 l.lwz r13,PT_PC(r1) 788 l.lwz r15,PT_SR(r1) 789 l.lwz r1,PT_SP(r1) 790 /* Interrupts need to be disabled for setting EPCR and ESR 791 * so that another interrupt doesn't come in here and clobber 792 * them before we can use them for our l.rfe */ 793 DISABLE_INTERRUPTS(r17,r19) 794 l.mtspr r0,r13,SPR_EPCR_BASE 795 l.mtspr r0,r15,SPR_ESR_BASE 796 l.rfe 797 798/* End of hot path! 799 * Keep the below tracing and error handling out of the hot path... 800*/ 801 802_syscall_trace_enter: 803 /* Here we pass pt_regs to do_syscall_trace_enter. Make sure 804 * that function is really getting all the info it needs as 805 * pt_regs isn't a complete set of userspace regs, just the 806 * ones relevant to the syscall... 807 * 808 * Note use of delay slot for setting argument. 809 */ 810 l.jal do_syscall_trace_enter 811 l.addi r3,r1,0 812 813 /* Restore arguments (not preserved across do_syscall_trace_enter) 814 * so that we can do the syscall for real and return to the syscall 815 * hot path. 816 */ 817 l.lwz r11,PT_GPR11(r1) 818 l.lwz r3,PT_GPR3(r1) 819 l.lwz r4,PT_GPR4(r1) 820 l.lwz r5,PT_GPR5(r1) 821 l.lwz r6,PT_GPR6(r1) 822 l.lwz r7,PT_GPR7(r1) 823 824 l.j _syscall_check 825 l.lwz r8,PT_GPR8(r1) 826 827_syscall_trace_leave: 828 l.jal do_syscall_trace_leave 829 l.addi r3,r1,0 830 831 l.j _syscall_check_work 832 l.nop 833 834_syscall_badsys: 835 /* Here we effectively pretend to have executed an imaginary 836 * syscall that returns -ENOSYS and then return to the regular 837 * syscall hot path. 838 * Note that "return value" is set in the delay slot... 839 */ 840 l.j _syscall_return 841 l.addi r11,r0,-ENOSYS 842 843/******* END SYSCALL HANDLING *******/ 844 845/* ---[ 0xd00: Floating Point exception ]-------------------------------- */ 846 847EXCEPTION_ENTRY(_fpe_trap_handler) 848 CLEAR_LWA_FLAG(r3) 849 850 /* r4: EA of fault (set by EXCEPTION_HANDLE) */ 851 l.jal do_fpe_trap 852 l.addi r3,r1,0 /* pt_regs */ 853 854 l.j _ret_from_exception 855 l.nop 856 857/* ---[ 0xe00: Trap exception ]------------------------------------------ */ 858 859EXCEPTION_ENTRY(_trap_handler) 860 CLEAR_LWA_FLAG(r3) 861 /* r4: EA of fault (set by EXCEPTION_HANDLE) */ 862 l.jal do_trap 863 l.addi r3,r1,0 /* pt_regs */ 864 865 l.j _ret_from_exception 866 l.nop 867 868/* ---[ 0xf00: Reserved exception ]-------------------------------------- */ 869 870UNHANDLED_EXCEPTION(_vector_0xf00,0xf00) 871 872/* ---[ 0x1000: Reserved exception ]------------------------------------- */ 873 874UNHANDLED_EXCEPTION(_vector_0x1000,0x1000) 875 876/* ---[ 0x1100: Reserved exception ]------------------------------------- */ 877 878UNHANDLED_EXCEPTION(_vector_0x1100,0x1100) 879 880/* ---[ 0x1200: Reserved exception ]------------------------------------- */ 881 882UNHANDLED_EXCEPTION(_vector_0x1200,0x1200) 883 884/* ---[ 0x1300: Reserved exception ]------------------------------------- */ 885 886UNHANDLED_EXCEPTION(_vector_0x1300,0x1300) 887 888/* ---[ 0x1400: Reserved exception ]------------------------------------- */ 889 890UNHANDLED_EXCEPTION(_vector_0x1400,0x1400) 891 892/* ---[ 0x1500: Reserved exception ]------------------------------------- */ 893 894UNHANDLED_EXCEPTION(_vector_0x1500,0x1500) 895 896/* ---[ 0x1600: Reserved exception ]------------------------------------- */ 897 898UNHANDLED_EXCEPTION(_vector_0x1600,0x1600) 899 900/* ---[ 0x1700: Reserved exception ]------------------------------------- */ 901 902UNHANDLED_EXCEPTION(_vector_0x1700,0x1700) 903 904/* ---[ 0x1800: Reserved exception ]------------------------------------- */ 905 906UNHANDLED_EXCEPTION(_vector_0x1800,0x1800) 907 908/* ---[ 0x1900: Reserved exception ]------------------------------------- */ 909 910UNHANDLED_EXCEPTION(_vector_0x1900,0x1900) 911 912/* ---[ 0x1a00: Reserved exception ]------------------------------------- */ 913 914UNHANDLED_EXCEPTION(_vector_0x1a00,0x1a00) 915 916/* ---[ 0x1b00: Reserved exception ]------------------------------------- */ 917 918UNHANDLED_EXCEPTION(_vector_0x1b00,0x1b00) 919 920/* ---[ 0x1c00: Reserved exception ]------------------------------------- */ 921 922UNHANDLED_EXCEPTION(_vector_0x1c00,0x1c00) 923 924/* ---[ 0x1d00: Reserved exception ]------------------------------------- */ 925 926UNHANDLED_EXCEPTION(_vector_0x1d00,0x1d00) 927 928/* ---[ 0x1e00: Reserved exception ]------------------------------------- */ 929 930UNHANDLED_EXCEPTION(_vector_0x1e00,0x1e00) 931 932/* ---[ 0x1f00: Reserved exception ]------------------------------------- */ 933 934UNHANDLED_EXCEPTION(_vector_0x1f00,0x1f00) 935 936/* ========================================================[ return ] === */ 937 938_resume_userspace: 939 DISABLE_INTERRUPTS(r3,r4) 940 TRACE_IRQS_OFF 941 l.lwz r4,TI_FLAGS(r10) 942 l.andi r13,r4,_TIF_WORK_MASK 943 l.sfeqi r13,0 944 l.bf _restore_all 945 l.nop 946 947_work_pending: 948 l.lwz r5,PT_ORIG_GPR11(r1) 949 l.sfltsi r5,0 950 l.bnf 1f 951 l.nop 952 l.andi r5,r5,0 9531: 954 l.jal do_work_pending 955 l.ori r3,r1,0 /* pt_regs */ 956 957 l.sfeqi r11,0 958 l.bf _restore_all 959 l.nop 960 l.sfltsi r11,0 961 l.bnf 1f 962 l.nop 963 l.and r11,r11,r0 964 l.ori r11,r11,__NR_restart_syscall 965 l.j _syscall_check_trace_enter 966 l.nop 9671: 968 l.lwz r11,PT_ORIG_GPR11(r1) 969 /* Restore arg registers */ 970 l.lwz r3,PT_GPR3(r1) 971 l.lwz r4,PT_GPR4(r1) 972 l.lwz r5,PT_GPR5(r1) 973 l.lwz r6,PT_GPR6(r1) 974 l.lwz r7,PT_GPR7(r1) 975 l.j _syscall_check_trace_enter 976 l.lwz r8,PT_GPR8(r1) 977 978_restore_all: 979#ifdef CONFIG_TRACE_IRQFLAGS 980 l.lwz r4,PT_SR(r1) 981 l.andi r3,r4,(SPR_SR_IEE|SPR_SR_TEE) 982 l.sfeq r3,r0 /* skip trace if irqs were off */ 983 l.bf skip_hardirqs_on 984 l.nop 985 TRACE_IRQS_ON 986skip_hardirqs_on: 987#endif 988 RESTORE_ALL 989 /* This returns to userspace code */ 990 991 992ENTRY(_ret_from_intr) 993ENTRY(_ret_from_exception) 994 l.lwz r4,PT_SR(r1) 995 l.andi r3,r4,SPR_SR_SM 996 l.sfeqi r3,0 997 l.bnf _restore_all 998 l.nop 999 l.j _resume_userspace 1000 l.nop 1001 1002ENTRY(ret_from_fork) 1003 l.jal schedule_tail 1004 l.nop 1005 1006 /* Check if we are a kernel thread */ 1007 l.sfeqi r20,0 1008 l.bf 1f 1009 l.nop 1010 1011 /* ...we are a kernel thread so invoke the requested callback */ 1012 l.jalr r20 1013 l.or r3,r22,r0 1014 10151: 1016 /* _syscall_returns expect r11 to contain return value */ 1017 l.lwz r11,PT_GPR11(r1) 1018 1019 /* The syscall fast path return expects call-saved registers 1020 * r14-r28 to be untouched, so we restore them here as they 1021 * will have been effectively clobbered when arriving here 1022 * via the call to switch() 1023 */ 1024 l.lwz r14,PT_GPR14(r1) 1025 l.lwz r16,PT_GPR16(r1) 1026 l.lwz r18,PT_GPR18(r1) 1027 l.lwz r20,PT_GPR20(r1) 1028 l.lwz r22,PT_GPR22(r1) 1029 l.lwz r24,PT_GPR24(r1) 1030 l.lwz r26,PT_GPR26(r1) 1031 l.lwz r28,PT_GPR28(r1) 1032 1033 l.j _syscall_return 1034 l.nop 1035 1036/* ========================================================[ switch ] === */ 1037 1038/* 1039 * This routine switches between two different tasks. The process 1040 * state of one is saved on its kernel stack. Then the state 1041 * of the other is restored from its kernel stack. The memory 1042 * management hardware is updated to the second process's state. 1043 * Finally, we can return to the second process, via the 'return'. 1044 * 1045 * Note: there are two ways to get to the "going out" portion 1046 * of this code; either by coming in via the entry (_switch) 1047 * or via "fork" which must set up an environment equivalent 1048 * to the "_switch" path. If you change this (or in particular, the 1049 * SAVE_REGS macro), you'll have to change the fork code also. 1050 */ 1051 1052 1053/* _switch MUST never lay on page boundry, cause it runs from 1054 * effective addresses and beeing interrupted by iTLB miss would kill it. 1055 * dTLB miss seems to never accour in the bad place since data accesses 1056 * are from task structures which are always page aligned. 1057 * 1058 * The problem happens in RESTORE_ALL where we first set the EPCR 1059 * register, then load the previous register values and only at the end call 1060 * the l.rfe instruction. If get TLB miss in beetwen the EPCR register gets 1061 * garbled and we end up calling l.rfe with the wrong EPCR. (same probably 1062 * holds for ESR) 1063 * 1064 * To avoid this problems it is sufficient to align _switch to 1065 * some nice round number smaller than it's size... 1066 */ 1067 1068/* ABI rules apply here... we either enter _switch via schedule() or via 1069 * an imaginary call to which we shall return at return_from_fork. Either 1070 * way, we are a function call and only need to preserve the callee-saved 1071 * registers when we return. As such, we don't need to save the registers 1072 * on the stack that we won't be returning as they were... 1073 */ 1074 1075 .align 0x400 1076ENTRY(_switch) 1077 /* We don't store SR as _switch only gets called in a context where 1078 * the SR will be the same going in and coming out... */ 1079 1080 /* Set up new pt_regs struct for saving task state */ 1081 l.addi r1,r1,-(INT_FRAME_SIZE) 1082 1083 /* No need to store r1/PT_SP as it goes into KSP below */ 1084 l.sw PT_GPR2(r1),r2 1085 l.sw PT_GPR9(r1),r9 1086 1087 /* Save callee-saved registers to the new pt_regs */ 1088 l.sw PT_GPR14(r1),r14 1089 l.sw PT_GPR16(r1),r16 1090 l.sw PT_GPR18(r1),r18 1091 l.sw PT_GPR20(r1),r20 1092 l.sw PT_GPR22(r1),r22 1093 l.sw PT_GPR24(r1),r24 1094 l.sw PT_GPR26(r1),r26 1095 l.sw PT_GPR28(r1),r28 1096 l.sw PT_GPR30(r1),r30 1097 1098 l.addi r11,r10,0 /* Save old 'current' to 'last' return value*/ 1099 1100 /* We use thread_info->ksp for storing the address of the above 1101 * structure so that we can get back to it later... we don't want 1102 * to lose the value of thread_info->ksp, though, so store it as 1103 * pt_regs->sp so that we can easily restore it when we are made 1104 * live again... 1105 */ 1106 1107 /* Save the old value of thread_info->ksp as pt_regs->sp */ 1108 l.lwz r29,TI_KSP(r10) 1109 l.sw PT_SP(r1),r29 1110 1111 /* Swap kernel stack pointers */ 1112 l.sw TI_KSP(r10),r1 /* Save old stack pointer */ 1113 l.or r10,r4,r0 /* Set up new current_thread_info */ 1114 l.lwz r1,TI_KSP(r10) /* Load new stack pointer */ 1115 1116 /* Restore the old value of thread_info->ksp */ 1117 l.lwz r29,PT_SP(r1) 1118 l.sw TI_KSP(r10),r29 1119 1120 /* ...and restore the registers, except r11 because the return value 1121 * has already been set above. 1122 */ 1123 l.lwz r2,PT_GPR2(r1) 1124 l.lwz r9,PT_GPR9(r1) 1125 /* No need to restore r10 */ 1126 /* ...and do not restore r11 */ 1127 1128 /* Restore callee-saved registers */ 1129 l.lwz r14,PT_GPR14(r1) 1130 l.lwz r16,PT_GPR16(r1) 1131 l.lwz r18,PT_GPR18(r1) 1132 l.lwz r20,PT_GPR20(r1) 1133 l.lwz r22,PT_GPR22(r1) 1134 l.lwz r24,PT_GPR24(r1) 1135 l.lwz r26,PT_GPR26(r1) 1136 l.lwz r28,PT_GPR28(r1) 1137 l.lwz r30,PT_GPR30(r1) 1138 1139 /* Unwind stack to pre-switch state */ 1140 l.addi r1,r1,(INT_FRAME_SIZE) 1141 1142 /* Return via the link-register back to where we 'came from', where 1143 * that may be either schedule(), ret_from_fork(), or 1144 * ret_from_kernel_thread(). If we are returning to a new thread, 1145 * we are expected to have set up the arg to schedule_tail already, 1146 * hence we do so here unconditionally: 1147 */ 1148 l.lwz r3,TI_TASK(r3) /* Load 'prev' as schedule_tail arg */ 1149 l.jr r9 1150 l.nop 1151 1152/* ==================================================================== */ 1153 1154/* These all use the delay slot for setting the argument register, so the 1155 * jump is always happening after the l.addi instruction. 1156 * 1157 * These are all just wrappers that don't touch the link-register r9, so the 1158 * return from the "real" syscall function will return back to the syscall 1159 * code that did the l.jal that brought us here. 1160 */ 1161 1162/* fork requires that we save all the callee-saved registers because they 1163 * are all effectively clobbered by the call to _switch. Here we store 1164 * all the registers that aren't touched by the syscall fast path and thus 1165 * weren't saved there. 1166 */ 1167 1168_fork_save_extra_regs_and_call: 1169 l.sw PT_GPR14(r1),r14 1170 l.sw PT_GPR16(r1),r16 1171 l.sw PT_GPR18(r1),r18 1172 l.sw PT_GPR20(r1),r20 1173 l.sw PT_GPR22(r1),r22 1174 l.sw PT_GPR24(r1),r24 1175 l.sw PT_GPR26(r1),r26 1176 l.jr r29 1177 l.sw PT_GPR28(r1),r28 1178 1179ENTRY(__sys_clone) 1180 l.movhi r29,hi(sys_clone) 1181 l.j _fork_save_extra_regs_and_call 1182 l.ori r29,r29,lo(sys_clone) 1183 1184ENTRY(__sys_clone3) 1185 l.movhi r29,hi(sys_clone3) 1186 l.j _fork_save_extra_regs_and_call 1187 l.ori r29,r29,lo(sys_clone3) 1188 1189ENTRY(__sys_fork) 1190 l.movhi r29,hi(sys_fork) 1191 l.j _fork_save_extra_regs_and_call 1192 l.ori r29,r29,lo(sys_fork) 1193 1194ENTRY(sys_rt_sigreturn) 1195 l.jal _sys_rt_sigreturn 1196 l.addi r3,r1,0 1197 l.sfne r30,r0 1198 l.bnf _no_syscall_trace 1199 l.nop 1200 l.jal do_syscall_trace_leave 1201 l.addi r3,r1,0 1202_no_syscall_trace: 1203 l.j _resume_userspace 1204 l.nop 1205 1206/* This is a catch-all syscall for atomic instructions for the OpenRISC 1000. 1207 * The functions takes a variable number of parameters depending on which 1208 * particular flavour of atomic you want... parameter 1 is a flag identifying 1209 * the atomic in question. Currently, this function implements the 1210 * following variants: 1211 * 1212 * XCHG: 1213 * @flag: 1 1214 * @ptr1: 1215 * @ptr2: 1216 * Atomically exchange the values in pointers 1 and 2. 1217 * 1218 */ 1219 1220ENTRY(sys_or1k_atomic) 1221 /* FIXME: This ignores r3 and always does an XCHG */ 1222 DISABLE_INTERRUPTS(r17,r19) 1223 l.lwz r29,0(r4) 1224 l.lwz r27,0(r5) 1225 l.sw 0(r4),r27 1226 l.sw 0(r5),r29 1227 ENABLE_INTERRUPTS(r17) 1228 l.jr r9 1229 l.or r11,r0,r0 1230 1231/* ============================================================[ EOF ]=== */ 1232