1/* 2 * linux/arch/arm/kernel/entry-armv.S 3 * 4 * Copyright (C) 1996,1997,1998 Russell King. 5 * ARM700 fix by Matthew Godbolt (linux-user@willothewisp.demon.co.uk) 6 * nommu support by Hyok S. Choi (hyok.choi@samsung.com) 7 * 8 * This program is free software; you can redistribute it and/or modify 9 * it under the terms of the GNU General Public License version 2 as 10 * published by the Free Software Foundation. 11 * 12 * Low-level vector interface routines 13 * 14 * Note: there is a StrongARM bug in the STMIA rn, {regs}^ instruction 15 * that causes it to save wrong values... Be aware! 16 */ 17 18#include <asm/assembler.h> 19#include <asm/memory.h> 20#include <asm/glue-df.h> 21#include <asm/glue-pf.h> 22#include <asm/vfpmacros.h> 23#ifndef CONFIG_MULTI_IRQ_HANDLER 24#include <mach/entry-macro.S> 25#endif 26#include <asm/thread_notify.h> 27#include <asm/unwind.h> 28#include <asm/unistd.h> 29#include <asm/tls.h> 30#include <asm/system_info.h> 31 32#include "entry-header.S" 33#include <asm/entry-macro-multi.S> 34 35/* 36 * Interrupt handling. 37 */ 38 .macro irq_handler 39#ifdef CONFIG_MULTI_IRQ_HANDLER 40 ldr r1, =handle_arch_irq 41 mov r0, sp 42 adr lr, BSYM(9997f) 43 ldr pc, [r1] 44#else 45 arch_irq_handler_default 46#endif 479997: 48 .endm 49 50 .macro pabt_helper 51 @ PABORT handler takes pt_regs in r2, fault address in r4 and psr in r5 52#ifdef MULTI_PABORT 53 ldr ip, .LCprocfns 54 mov lr, pc 55 ldr pc, [ip, #PROCESSOR_PABT_FUNC] 56#else 57 bl CPU_PABORT_HANDLER 58#endif 59 .endm 60 61 .macro dabt_helper 62 63 @ 64 @ Call the processor-specific abort handler: 65 @ 66 @ r2 - pt_regs 67 @ r4 - aborted context pc 68 @ r5 - aborted context psr 69 @ 70 @ The abort handler must return the aborted address in r0, and 71 @ the fault status register in r1. r9 must be preserved. 72 @ 73#ifdef MULTI_DABORT 74 ldr ip, .LCprocfns 75 mov lr, pc 76 ldr pc, [ip, #PROCESSOR_DABT_FUNC] 77#else 78 bl CPU_DABORT_HANDLER 79#endif 80 .endm 81 82#ifdef CONFIG_KPROBES 83 .section .kprobes.text,"ax",%progbits 84#else 85 .text 86#endif 87 88/* 89 * Invalid mode handlers 90 */ 91 .macro inv_entry, reason 92 sub sp, sp, #S_FRAME_SIZE 93 ARM( stmib sp, {r1 - lr} ) 94 THUMB( stmia sp, {r0 - r12} ) 95 THUMB( str sp, [sp, #S_SP] ) 96 THUMB( str lr, [sp, #S_LR] ) 97 mov r1, #\reason 98 .endm 99 100__pabt_invalid: 101 inv_entry BAD_PREFETCH 102 b common_invalid 103ENDPROC(__pabt_invalid) 104 105__dabt_invalid: 106 inv_entry BAD_DATA 107 b common_invalid 108ENDPROC(__dabt_invalid) 109 110__irq_invalid: 111 inv_entry BAD_IRQ 112 b common_invalid 113ENDPROC(__irq_invalid) 114 115__und_invalid: 116 inv_entry BAD_UNDEFINSTR 117 118 @ 119 @ XXX fall through to common_invalid 120 @ 121 122@ 123@ common_invalid - generic code for failed exception (re-entrant version of handlers) 124@ 125common_invalid: 126 zero_fp 127 128 ldmia r0, {r4 - r6} 129 add r0, sp, #S_PC @ here for interlock avoidance 130 mov r7, #-1 @ "" "" "" "" 131 str r4, [sp] @ save preserved r0 132 stmia r0, {r5 - r7} @ lr_<exception>, 133 @ cpsr_<exception>, "old_r0" 134 135 mov r0, sp 136 b bad_mode 137ENDPROC(__und_invalid) 138 139/* 140 * SVC mode handlers 141 */ 142 143#if defined(CONFIG_AEABI) && (__LINUX_ARM_ARCH__ >= 5) 144#define SPFIX(code...) code 145#else 146#define SPFIX(code...) 147#endif 148 149 .macro svc_entry, stack_hole=0 150 UNWIND(.fnstart ) 151 UNWIND(.save {r0 - pc} ) 152 sub sp, sp, #(S_FRAME_SIZE + \stack_hole - 4) 153#ifdef CONFIG_THUMB2_KERNEL 154 SPFIX( str r0, [sp] ) @ temporarily saved 155 SPFIX( mov r0, sp ) 156 SPFIX( tst r0, #4 ) @ test original stack alignment 157 SPFIX( ldr r0, [sp] ) @ restored 158#else 159 SPFIX( tst sp, #4 ) 160#endif 161 SPFIX( subeq sp, sp, #4 ) 162 stmia sp, {r1 - r12} 163 164 ldmia r0, {r3 - r5} 165 add r7, sp, #S_SP - 4 @ here for interlock avoidance 166 mov r6, #-1 @ "" "" "" "" 167 add r2, sp, #(S_FRAME_SIZE + \stack_hole - 4) 168 SPFIX( addeq r2, r2, #4 ) 169 str r3, [sp, #-4]! @ save the "real" r0 copied 170 @ from the exception stack 171 172 mov r3, lr 173 174 @ 175 @ We are now ready to fill in the remaining blanks on the stack: 176 @ 177 @ r2 - sp_svc 178 @ r3 - lr_svc 179 @ r4 - lr_<exception>, already fixed up for correct return/restart 180 @ r5 - spsr_<exception> 181 @ r6 - orig_r0 (see pt_regs definition in ptrace.h) 182 @ 183 stmia r7, {r2 - r6} 184 185#ifdef CONFIG_TRACE_IRQFLAGS 186 bl trace_hardirqs_off 187#endif 188 .endm 189 190 .align 5 191__dabt_svc: 192 svc_entry 193 mov r2, sp 194 dabt_helper 195 196 @ 197 @ IRQs off again before pulling preserved data off the stack 198 @ 199 disable_irq_notrace 200 201#ifdef CONFIG_TRACE_IRQFLAGS 202 tst r5, #PSR_I_BIT 203 bleq trace_hardirqs_on 204 tst r5, #PSR_I_BIT 205 blne trace_hardirqs_off 206#endif 207 svc_exit r5 @ return from exception 208 UNWIND(.fnend ) 209ENDPROC(__dabt_svc) 210 211 .align 5 212__irq_svc: 213 svc_entry 214 irq_handler 215 216#ifdef CONFIG_PREEMPT 217 get_thread_info tsk 218 ldr r8, [tsk, #TI_PREEMPT] @ get preempt count 219 ldr r0, [tsk, #TI_FLAGS] @ get flags 220 teq r8, #0 @ if preempt count != 0 221 movne r0, #0 @ force flags to 0 222 tst r0, #_TIF_NEED_RESCHED 223 blne svc_preempt 224#endif 225 226#ifdef CONFIG_TRACE_IRQFLAGS 227 @ The parent context IRQs must have been enabled to get here in 228 @ the first place, so there's no point checking the PSR I bit. 229 bl trace_hardirqs_on 230#endif 231 svc_exit r5 @ return from exception 232 UNWIND(.fnend ) 233ENDPROC(__irq_svc) 234 235 .ltorg 236 237#ifdef CONFIG_PREEMPT 238svc_preempt: 239 mov r8, lr 2401: bl preempt_schedule_irq @ irq en/disable is done inside 241 ldr r0, [tsk, #TI_FLAGS] @ get new tasks TI_FLAGS 242 tst r0, #_TIF_NEED_RESCHED 243 moveq pc, r8 @ go again 244 b 1b 245#endif 246 247__und_fault: 248 @ Correct the PC such that it is pointing at the instruction 249 @ which caused the fault. If the faulting instruction was ARM 250 @ the PC will be pointing at the next instruction, and have to 251 @ subtract 4. Otherwise, it is Thumb, and the PC will be 252 @ pointing at the second half of the Thumb instruction. We 253 @ have to subtract 2. 254 ldr r2, [r0, #S_PC] 255 sub r2, r2, r1 256 str r2, [r0, #S_PC] 257 b do_undefinstr 258ENDPROC(__und_fault) 259 260 .align 5 261__und_svc: 262#ifdef CONFIG_KPROBES 263 @ If a kprobe is about to simulate a "stmdb sp..." instruction, 264 @ it obviously needs free stack space which then will belong to 265 @ the saved context. 266 svc_entry 64 267#else 268 svc_entry 269#endif 270 @ 271 @ call emulation code, which returns using r9 if it has emulated 272 @ the instruction, or the more conventional lr if we are to treat 273 @ this as a real undefined instruction 274 @ 275 @ r0 - instruction 276 @ 277#ifndef CONFIG_THUMB2_KERNEL 278 ldr r0, [r4, #-4] 279#else 280 mov r1, #2 281 ldrh r0, [r4, #-2] @ Thumb instruction at LR - 2 282 cmp r0, #0xe800 @ 32-bit instruction if xx >= 0 283 blo __und_svc_fault 284 ldrh r9, [r4] @ bottom 16 bits 285 add r4, r4, #2 286 str r4, [sp, #S_PC] 287 orr r0, r9, r0, lsl #16 288#endif 289 adr r9, BSYM(__und_svc_finish) 290 mov r2, r4 291 bl call_fpe 292 293 mov r1, #4 @ PC correction to apply 294__und_svc_fault: 295 mov r0, sp @ struct pt_regs *regs 296 bl __und_fault 297 298 @ 299 @ IRQs off again before pulling preserved data off the stack 300 @ 301__und_svc_finish: 302 disable_irq_notrace 303 304 @ 305 @ restore SPSR and restart the instruction 306 @ 307 ldr r5, [sp, #S_PSR] @ Get SVC cpsr 308#ifdef CONFIG_TRACE_IRQFLAGS 309 tst r5, #PSR_I_BIT 310 bleq trace_hardirqs_on 311 tst r5, #PSR_I_BIT 312 blne trace_hardirqs_off 313#endif 314 svc_exit r5 @ return from exception 315 UNWIND(.fnend ) 316ENDPROC(__und_svc) 317 318 .align 5 319__pabt_svc: 320 svc_entry 321 mov r2, sp @ regs 322 pabt_helper 323 324 @ 325 @ IRQs off again before pulling preserved data off the stack 326 @ 327 disable_irq_notrace 328 329#ifdef CONFIG_TRACE_IRQFLAGS 330 tst r5, #PSR_I_BIT 331 bleq trace_hardirqs_on 332 tst r5, #PSR_I_BIT 333 blne trace_hardirqs_off 334#endif 335 svc_exit r5 @ return from exception 336 UNWIND(.fnend ) 337ENDPROC(__pabt_svc) 338 339 .align 5 340.LCcralign: 341 .word cr_alignment 342#ifdef MULTI_DABORT 343.LCprocfns: 344 .word processor 345#endif 346.LCfp: 347 .word fp_enter 348 349/* 350 * User mode handlers 351 * 352 * EABI note: sp_svc is always 64-bit aligned here, so should S_FRAME_SIZE 353 */ 354 355#if defined(CONFIG_AEABI) && (__LINUX_ARM_ARCH__ >= 5) && (S_FRAME_SIZE & 7) 356#error "sizeof(struct pt_regs) must be a multiple of 8" 357#endif 358 359 .macro usr_entry 360 UNWIND(.fnstart ) 361 UNWIND(.cantunwind ) @ don't unwind the user space 362 sub sp, sp, #S_FRAME_SIZE 363 ARM( stmib sp, {r1 - r12} ) 364 THUMB( stmia sp, {r0 - r12} ) 365 366 ldmia r0, {r3 - r5} 367 add r0, sp, #S_PC @ here for interlock avoidance 368 mov r6, #-1 @ "" "" "" "" 369 370 str r3, [sp] @ save the "real" r0 copied 371 @ from the exception stack 372 373 @ 374 @ We are now ready to fill in the remaining blanks on the stack: 375 @ 376 @ r4 - lr_<exception>, already fixed up for correct return/restart 377 @ r5 - spsr_<exception> 378 @ r6 - orig_r0 (see pt_regs definition in ptrace.h) 379 @ 380 @ Also, separately save sp_usr and lr_usr 381 @ 382 stmia r0, {r4 - r6} 383 ARM( stmdb r0, {sp, lr}^ ) 384 THUMB( store_user_sp_lr r0, r1, S_SP - S_PC ) 385 386 @ 387 @ Enable the alignment trap while in kernel mode 388 @ 389 alignment_trap r0 390 391 @ 392 @ Clear FP to mark the first stack frame 393 @ 394 zero_fp 395 396#ifdef CONFIG_IRQSOFF_TRACER 397 bl trace_hardirqs_off 398#endif 399 .endm 400 401 .macro kuser_cmpxchg_check 402#if !defined(CONFIG_CPU_32v6K) && !defined(CONFIG_NEEDS_SYSCALL_FOR_CMPXCHG) 403#ifndef CONFIG_MMU 404#warning "NPTL on non MMU needs fixing" 405#else 406 @ Make sure our user space atomic helper is restarted 407 @ if it was interrupted in a critical region. Here we 408 @ perform a quick test inline since it should be false 409 @ 99.9999% of the time. The rest is done out of line. 410 cmp r4, #TASK_SIZE 411 blhs kuser_cmpxchg64_fixup 412#endif 413#endif 414 .endm 415 416 .align 5 417__dabt_usr: 418 usr_entry 419 kuser_cmpxchg_check 420 mov r2, sp 421 dabt_helper 422 b ret_from_exception 423 UNWIND(.fnend ) 424ENDPROC(__dabt_usr) 425 426 .align 5 427__irq_usr: 428 usr_entry 429 kuser_cmpxchg_check 430 irq_handler 431 get_thread_info tsk 432 mov why, #0 433 b ret_to_user_from_irq 434 UNWIND(.fnend ) 435ENDPROC(__irq_usr) 436 437 .ltorg 438 439 .align 5 440__und_usr: 441 usr_entry 442 443 mov r2, r4 444 mov r3, r5 445 446 @ r2 = regs->ARM_pc, which is either 2 or 4 bytes ahead of the 447 @ faulting instruction depending on Thumb mode. 448 @ r3 = regs->ARM_cpsr 449 @ 450 @ The emulation code returns using r9 if it has emulated the 451 @ instruction, or the more conventional lr if we are to treat 452 @ this as a real undefined instruction 453 @ 454 adr r9, BSYM(ret_from_exception) 455 456 tst r3, #PSR_T_BIT @ Thumb mode? 457 bne __und_usr_thumb 458 sub r4, r2, #4 @ ARM instr at LR - 4 4591: ldrt r0, [r4] 460#ifdef CONFIG_CPU_ENDIAN_BE8 461 rev r0, r0 @ little endian instruction 462#endif 463 @ r0 = 32-bit ARM instruction which caused the exception 464 @ r2 = PC value for the following instruction (:= regs->ARM_pc) 465 @ r4 = PC value for the faulting instruction 466 @ lr = 32-bit undefined instruction function 467 adr lr, BSYM(__und_usr_fault_32) 468 b call_fpe 469 470__und_usr_thumb: 471 @ Thumb instruction 472 sub r4, r2, #2 @ First half of thumb instr at LR - 2 473#if CONFIG_ARM_THUMB && __LINUX_ARM_ARCH__ >= 6 && CONFIG_CPU_V7 474/* 475 * Thumb-2 instruction handling. Note that because pre-v6 and >= v6 platforms 476 * can never be supported in a single kernel, this code is not applicable at 477 * all when __LINUX_ARM_ARCH__ < 6. This allows simplifying assumptions to be 478 * made about .arch directives. 479 */ 480#if __LINUX_ARM_ARCH__ < 7 481/* If the target CPU may not be Thumb-2-capable, a run-time check is needed: */ 482#define NEED_CPU_ARCHITECTURE 483 ldr r5, .LCcpu_architecture 484 ldr r5, [r5] 485 cmp r5, #CPU_ARCH_ARMv7 486 blo __und_usr_fault_16 @ 16bit undefined instruction 487/* 488 * The following code won't get run unless the running CPU really is v7, so 489 * coding round the lack of ldrht on older arches is pointless. Temporarily 490 * override the assembler target arch with the minimum required instead: 491 */ 492 .arch armv6t2 493#endif 4942: ldrht r5, [r4] 495 cmp r5, #0xe800 @ 32bit instruction if xx != 0 496 blo __und_usr_fault_16 @ 16bit undefined instruction 4973: ldrht r0, [r2] 498 add r2, r2, #2 @ r2 is PC + 2, make it PC + 4 499 str r2, [sp, #S_PC] @ it's a 2x16bit instr, update 500 orr r0, r0, r5, lsl #16 501 adr lr, BSYM(__und_usr_fault_32) 502 @ r0 = the two 16-bit Thumb instructions which caused the exception 503 @ r2 = PC value for the following Thumb instruction (:= regs->ARM_pc) 504 @ r4 = PC value for the first 16-bit Thumb instruction 505 @ lr = 32bit undefined instruction function 506 507#if __LINUX_ARM_ARCH__ < 7 508/* If the target arch was overridden, change it back: */ 509#ifdef CONFIG_CPU_32v6K 510 .arch armv6k 511#else 512 .arch armv6 513#endif 514#endif /* __LINUX_ARM_ARCH__ < 7 */ 515#else /* !(CONFIG_ARM_THUMB && __LINUX_ARM_ARCH__ >= 6 && CONFIG_CPU_V7) */ 516 b __und_usr_fault_16 517#endif 518 UNWIND(.fnend) 519ENDPROC(__und_usr) 520 521/* 522 * The out of line fixup for the ldrt instructions above. 523 */ 524 .pushsection .fixup, "ax" 5254: mov pc, r9 526 .popsection 527 .pushsection __ex_table,"a" 528 .long 1b, 4b 529#if CONFIG_ARM_THUMB && __LINUX_ARM_ARCH__ >= 6 && CONFIG_CPU_V7 530 .long 2b, 4b 531 .long 3b, 4b 532#endif 533 .popsection 534 535/* 536 * Check whether the instruction is a co-processor instruction. 537 * If yes, we need to call the relevant co-processor handler. 538 * 539 * Note that we don't do a full check here for the co-processor 540 * instructions; all instructions with bit 27 set are well 541 * defined. The only instructions that should fault are the 542 * co-processor instructions. However, we have to watch out 543 * for the ARM6/ARM7 SWI bug. 544 * 545 * NEON is a special case that has to be handled here. Not all 546 * NEON instructions are co-processor instructions, so we have 547 * to make a special case of checking for them. Plus, there's 548 * five groups of them, so we have a table of mask/opcode pairs 549 * to check against, and if any match then we branch off into the 550 * NEON handler code. 551 * 552 * Emulators may wish to make use of the following registers: 553 * r0 = instruction opcode (32-bit ARM or two 16-bit Thumb) 554 * r2 = PC value to resume execution after successful emulation 555 * r9 = normal "successful" return address 556 * r10 = this threads thread_info structure 557 * lr = unrecognised instruction return address 558 * IRQs disabled, FIQs enabled. 559 */ 560 @ 561 @ Fall-through from Thumb-2 __und_usr 562 @ 563#ifdef CONFIG_NEON 564 adr r6, .LCneon_thumb_opcodes 565 b 2f 566#endif 567call_fpe: 568#ifdef CONFIG_NEON 569 adr r6, .LCneon_arm_opcodes 5702: 571 ldr r7, [r6], #4 @ mask value 572 cmp r7, #0 @ end mask? 573 beq 1f 574 and r8, r0, r7 575 ldr r7, [r6], #4 @ opcode bits matching in mask 576 cmp r8, r7 @ NEON instruction? 577 bne 2b 578 get_thread_info r10 579 mov r7, #1 580 strb r7, [r10, #TI_USED_CP + 10] @ mark CP#10 as used 581 strb r7, [r10, #TI_USED_CP + 11] @ mark CP#11 as used 582 b do_vfp @ let VFP handler handle this 5831: 584#endif 585 tst r0, #0x08000000 @ only CDP/CPRT/LDC/STC have bit 27 586 tstne r0, #0x04000000 @ bit 26 set on both ARM and Thumb-2 587#if defined(CONFIG_CPU_ARM610) || defined(CONFIG_CPU_ARM710) 588 and r8, r0, #0x0f000000 @ mask out op-code bits 589 teqne r8, #0x0f000000 @ SWI (ARM6/7 bug)? 590#endif 591 moveq pc, lr 592 get_thread_info r10 @ get current thread 593 and r8, r0, #0x00000f00 @ mask out CP number 594 THUMB( lsr r8, r8, #8 ) 595 mov r7, #1 596 add r6, r10, #TI_USED_CP 597 ARM( strb r7, [r6, r8, lsr #8] ) @ set appropriate used_cp[] 598 THUMB( strb r7, [r6, r8] ) @ set appropriate used_cp[] 599#ifdef CONFIG_IWMMXT 600 @ Test if we need to give access to iWMMXt coprocessors 601 ldr r5, [r10, #TI_FLAGS] 602 rsbs r7, r8, #(1 << 8) @ CP 0 or 1 only 603 movcss r7, r5, lsr #(TIF_USING_IWMMXT + 1) 604 bcs iwmmxt_task_enable 605#endif 606 ARM( add pc, pc, r8, lsr #6 ) 607 THUMB( lsl r8, r8, #2 ) 608 THUMB( add pc, r8 ) 609 nop 610 611 movw_pc lr @ CP#0 612 W(b) do_fpe @ CP#1 (FPE) 613 W(b) do_fpe @ CP#2 (FPE) 614 movw_pc lr @ CP#3 615#ifdef CONFIG_CRUNCH 616 b crunch_task_enable @ CP#4 (MaverickCrunch) 617 b crunch_task_enable @ CP#5 (MaverickCrunch) 618 b crunch_task_enable @ CP#6 (MaverickCrunch) 619#else 620 movw_pc lr @ CP#4 621 movw_pc lr @ CP#5 622 movw_pc lr @ CP#6 623#endif 624 movw_pc lr @ CP#7 625 movw_pc lr @ CP#8 626 movw_pc lr @ CP#9 627#ifdef CONFIG_VFP 628 W(b) do_vfp @ CP#10 (VFP) 629 W(b) do_vfp @ CP#11 (VFP) 630#else 631 movw_pc lr @ CP#10 (VFP) 632 movw_pc lr @ CP#11 (VFP) 633#endif 634 movw_pc lr @ CP#12 635 movw_pc lr @ CP#13 636 movw_pc lr @ CP#14 (Debug) 637 movw_pc lr @ CP#15 (Control) 638 639#ifdef NEED_CPU_ARCHITECTURE 640 .align 2 641.LCcpu_architecture: 642 .word __cpu_architecture 643#endif 644 645#ifdef CONFIG_NEON 646 .align 6 647 648.LCneon_arm_opcodes: 649 .word 0xfe000000 @ mask 650 .word 0xf2000000 @ opcode 651 652 .word 0xff100000 @ mask 653 .word 0xf4000000 @ opcode 654 655 .word 0x00000000 @ mask 656 .word 0x00000000 @ opcode 657 658.LCneon_thumb_opcodes: 659 .word 0xef000000 @ mask 660 .word 0xef000000 @ opcode 661 662 .word 0xff100000 @ mask 663 .word 0xf9000000 @ opcode 664 665 .word 0x00000000 @ mask 666 .word 0x00000000 @ opcode 667#endif 668 669do_fpe: 670 enable_irq 671 ldr r4, .LCfp 672 add r10, r10, #TI_FPSTATE @ r10 = workspace 673 ldr pc, [r4] @ Call FP module USR entry point 674 675/* 676 * The FP module is called with these registers set: 677 * r0 = instruction 678 * r2 = PC+4 679 * r9 = normal "successful" return address 680 * r10 = FP workspace 681 * lr = unrecognised FP instruction return address 682 */ 683 684 .pushsection .data 685ENTRY(fp_enter) 686 .word no_fp 687 .popsection 688 689ENTRY(no_fp) 690 mov pc, lr 691ENDPROC(no_fp) 692 693__und_usr_fault_32: 694 mov r1, #4 695 b 1f 696__und_usr_fault_16: 697 mov r1, #2 6981: enable_irq 699 mov r0, sp 700 adr lr, BSYM(ret_from_exception) 701 b __und_fault 702ENDPROC(__und_usr_fault_32) 703ENDPROC(__und_usr_fault_16) 704 705 .align 5 706__pabt_usr: 707 usr_entry 708 mov r2, sp @ regs 709 pabt_helper 710 UNWIND(.fnend ) 711 /* fall through */ 712/* 713 * This is the return code to user mode for abort handlers 714 */ 715ENTRY(ret_from_exception) 716 UNWIND(.fnstart ) 717 UNWIND(.cantunwind ) 718 get_thread_info tsk 719 mov why, #0 720 b ret_to_user 721 UNWIND(.fnend ) 722ENDPROC(__pabt_usr) 723ENDPROC(ret_from_exception) 724 725/* 726 * Register switch for ARMv3 and ARMv4 processors 727 * r0 = previous task_struct, r1 = previous thread_info, r2 = next thread_info 728 * previous and next are guaranteed not to be the same. 729 */ 730ENTRY(__switch_to) 731 UNWIND(.fnstart ) 732 UNWIND(.cantunwind ) 733 add ip, r1, #TI_CPU_SAVE 734 ldr r3, [r2, #TI_TP_VALUE] 735 ARM( stmia ip!, {r4 - sl, fp, sp, lr} ) @ Store most regs on stack 736 THUMB( stmia ip!, {r4 - sl, fp} ) @ Store most regs on stack 737 THUMB( str sp, [ip], #4 ) 738 THUMB( str lr, [ip], #4 ) 739#ifdef CONFIG_CPU_USE_DOMAINS 740 ldr r6, [r2, #TI_CPU_DOMAIN] 741#endif 742 set_tls r3, r4, r5 743#if defined(CONFIG_CC_STACKPROTECTOR) && !defined(CONFIG_SMP) 744 ldr r7, [r2, #TI_TASK] 745 ldr r8, =__stack_chk_guard 746 ldr r7, [r7, #TSK_STACK_CANARY] 747#endif 748#ifdef CONFIG_CPU_USE_DOMAINS 749 mcr p15, 0, r6, c3, c0, 0 @ Set domain register 750#endif 751 mov r5, r0 752 add r4, r2, #TI_CPU_SAVE 753 ldr r0, =thread_notify_head 754 mov r1, #THREAD_NOTIFY_SWITCH 755 bl atomic_notifier_call_chain 756#if defined(CONFIG_CC_STACKPROTECTOR) && !defined(CONFIG_SMP) 757 str r7, [r8] 758#endif 759 THUMB( mov ip, r4 ) 760#ifdef CONFIG_QEMU_TRACE 761/* 762 mcr p15, 0, r0, c15, c0, 0 @ signal context switch 763*/ 764#endif 765 mov r0, r5 766 ARM( ldmia r4, {r4 - sl, fp, sp, pc} ) @ Load all regs saved previously 767 THUMB( ldmia ip!, {r4 - sl, fp} ) @ Load all regs saved previously 768 THUMB( ldr sp, [ip], #4 ) 769 THUMB( ldr pc, [ip] ) 770 UNWIND(.fnend ) 771ENDPROC(__switch_to) 772 773 __INIT 774 775/* 776 * User helpers. 777 * 778 * Each segment is 32-byte aligned and will be moved to the top of the high 779 * vector page. New segments (if ever needed) must be added in front of 780 * existing ones. This mechanism should be used only for things that are 781 * really small and justified, and not be abused freely. 782 * 783 * See Documentation/arm/kernel_user_helpers.txt for formal definitions. 784 */ 785 THUMB( .arm ) 786 787 .macro usr_ret, reg 788#ifdef CONFIG_ARM_THUMB 789 bx \reg 790#else 791 mov pc, \reg 792#endif 793 .endm 794 795 .macro kuser_pad, sym, size 796 .if (. - \sym) & 3 797 .rept 4 - (. - \sym) & 3 798 .byte 0 799 .endr 800 .endif 801 .rept (\size - (. - \sym)) / 4 802 .word 0xe7fddef1 803 .endr 804 .endm 805 806#ifdef CONFIG_KUSER_HELPERS 807 .align 5 808 .globl __kuser_helper_start 809__kuser_helper_start: 810 811/* 812 * Due to the length of some sequences, __kuser_cmpxchg64 spans 2 regular 813 * kuser "slots", therefore 0xffff0f80 is not used as a valid entry point. 814 */ 815 816__kuser_cmpxchg64: @ 0xffff0f60 817 818#if defined(CONFIG_NEEDS_SYSCALL_FOR_CMPXCHG) 819 820 /* 821 * Poor you. No fast solution possible... 822 * The kernel itself must perform the operation. 823 * A special ghost syscall is used for that (see traps.c). 824 */ 825 stmfd sp!, {r7, lr} 826 ldr r7, 1f @ it's 20 bits 827 swi __ARM_NR_cmpxchg64 828 ldmfd sp!, {r7, pc} 8291: .word __ARM_NR_cmpxchg64 830 831#elif defined(CONFIG_CPU_32v6K) 832 833 stmfd sp!, {r4, r5, r6, r7} 834 ldrd r4, r5, [r0] @ load old val 835 ldrd r6, r7, [r1] @ load new val 836 smp_dmb arm 8371: ldrexd r0, r1, [r2] @ load current val 838 eors r3, r0, r4 @ compare with oldval (1) 839 eoreqs r3, r1, r5 @ compare with oldval (2) 840 strexdeq r3, r6, r7, [r2] @ store newval if eq 841 teqeq r3, #1 @ success? 842 beq 1b @ if no then retry 843 smp_dmb arm 844 rsbs r0, r3, #0 @ set returned val and C flag 845 ldmfd sp!, {r4, r5, r6, r7} 846 usr_ret lr 847 848#elif !defined(CONFIG_SMP) 849 850#ifdef CONFIG_MMU 851 852 /* 853 * The only thing that can break atomicity in this cmpxchg64 854 * implementation is either an IRQ or a data abort exception 855 * causing another process/thread to be scheduled in the middle of 856 * the critical sequence. The same strategy as for cmpxchg is used. 857 */ 858 stmfd sp!, {r4, r5, r6, lr} 859 ldmia r0, {r4, r5} @ load old val 860 ldmia r1, {r6, lr} @ load new val 8611: ldmia r2, {r0, r1} @ load current val 862 eors r3, r0, r4 @ compare with oldval (1) 863 eoreqs r3, r1, r5 @ compare with oldval (2) 8642: stmeqia r2, {r6, lr} @ store newval if eq 865 rsbs r0, r3, #0 @ set return val and C flag 866 ldmfd sp!, {r4, r5, r6, pc} 867 868 .text 869kuser_cmpxchg64_fixup: 870 @ Called from kuser_cmpxchg_fixup. 871 @ r4 = address of interrupted insn (must be preserved). 872 @ sp = saved regs. r7 and r8 are clobbered. 873 @ 1b = first critical insn, 2b = last critical insn. 874 @ If r4 >= 1b and r4 <= 2b then saved pc_usr is set to 1b. 875 mov r7, #0xffff0fff 876 sub r7, r7, #(0xffff0fff - (0xffff0f60 + (1b - __kuser_cmpxchg64))) 877 subs r8, r4, r7 878 rsbcss r8, r8, #(2b - 1b) 879 strcs r7, [sp, #S_PC] 880#if __LINUX_ARM_ARCH__ < 6 881 bcc kuser_cmpxchg32_fixup 882#endif 883 mov pc, lr 884 .previous 885 886#else 887#warning "NPTL on non MMU needs fixing" 888 mov r0, #-1 889 adds r0, r0, #0 890 usr_ret lr 891#endif 892 893#else 894#error "incoherent kernel configuration" 895#endif 896 897 kuser_pad __kuser_cmpxchg64, 64 898 899__kuser_memory_barrier: @ 0xffff0fa0 900 smp_dmb arm 901 usr_ret lr 902 903 kuser_pad __kuser_memory_barrier, 32 904 905__kuser_cmpxchg: @ 0xffff0fc0 906 907#if defined(CONFIG_NEEDS_SYSCALL_FOR_CMPXCHG) 908 909 /* 910 * Poor you. No fast solution possible... 911 * The kernel itself must perform the operation. 912 * A special ghost syscall is used for that (see traps.c). 913 */ 914 stmfd sp!, {r7, lr} 915 ldr r7, 1f @ it's 20 bits 916 swi __ARM_NR_cmpxchg 917 ldmfd sp!, {r7, pc} 9181: .word __ARM_NR_cmpxchg 919 920#elif __LINUX_ARM_ARCH__ < 6 921 922#ifdef CONFIG_MMU 923 924 /* 925 * The only thing that can break atomicity in this cmpxchg 926 * implementation is either an IRQ or a data abort exception 927 * causing another process/thread to be scheduled in the middle 928 * of the critical sequence. To prevent this, code is added to 929 * the IRQ and data abort exception handlers to set the pc back 930 * to the beginning of the critical section if it is found to be 931 * within that critical section (see kuser_cmpxchg_fixup). 932 */ 9331: ldr r3, [r2] @ load current val 934 subs r3, r3, r0 @ compare with oldval 9352: streq r1, [r2] @ store newval if eq 936 rsbs r0, r3, #0 @ set return val and C flag 937 usr_ret lr 938 939 .text 940kuser_cmpxchg32_fixup: 941 @ Called from kuser_cmpxchg_check macro. 942 @ r4 = address of interrupted insn (must be preserved). 943 @ sp = saved regs. r7 and r8 are clobbered. 944 @ 1b = first critical insn, 2b = last critical insn. 945 @ If r4 >= 1b and r4 <= 2b then saved pc_usr is set to 1b. 946 mov r7, #0xffff0fff 947 sub r7, r7, #(0xffff0fff - (0xffff0fc0 + (1b - __kuser_cmpxchg))) 948 subs r8, r4, r7 949 rsbcss r8, r8, #(2b - 1b) 950 strcs r7, [sp, #S_PC] 951 mov pc, lr 952 .previous 953 954#else 955#warning "NPTL on non MMU needs fixing" 956 mov r0, #-1 957 adds r0, r0, #0 958 usr_ret lr 959#endif 960 961#else 962 963 smp_dmb arm 9641: ldrex r3, [r2] 965 subs r3, r3, r0 966 strexeq r3, r1, [r2] 967 teqeq r3, #1 968 beq 1b 969 rsbs r0, r3, #0 970 /* beware -- each __kuser slot must be 8 instructions max */ 971 ALT_SMP(b __kuser_memory_barrier) 972 ALT_UP(usr_ret lr) 973 974#endif 975 976 kuser_pad __kuser_cmpxchg, 32 977 978__kuser_get_tls: @ 0xffff0fe0 979 ldr r0, [pc, #(16 - 8)] @ read TLS, set in kuser_get_tls_init 980 usr_ret lr 981 mrc p15, 0, r0, c13, c0, 3 @ 0xffff0fe8 hardware TLS code 982 kuser_pad __kuser_get_tls, 16 983 .rep 3 984 .word 0 @ 0xffff0ff0 software TLS value, then 985 .endr @ pad up to __kuser_helper_version 986 987__kuser_helper_version: @ 0xffff0ffc 988 .word ((__kuser_helper_end - __kuser_helper_start) >> 5) 989 990 .globl __kuser_helper_end 991__kuser_helper_end: 992 993#endif 994 995 THUMB( .thumb ) 996 997/* 998 * Vector stubs. 999 * 1000 * This code is copied to 0xffff1000 so we can use branches in the 1001 * vectors, rather than ldr's. Note that this code must not exceed 1002 * a page size. 1003 * 1004 * Common stub entry macro: 1005 * Enter in IRQ mode, spsr = SVC/USR CPSR, lr = SVC/USR PC 1006 * 1007 * SP points to a minimal amount of processor-private memory, the address 1008 * of which is copied into r0 for the mode specific abort handler. 1009 */ 1010 .macro vector_stub, name, mode, correction=0 1011 .align 5 1012 1013vector_\name: 1014 .if \correction 1015 sub lr, lr, #\correction 1016 .endif 1017 1018 @ 1019 @ Save r0, lr_<exception> (parent PC) and spsr_<exception> 1020 @ (parent CPSR) 1021 @ 1022 stmia sp, {r0, lr} @ save r0, lr 1023 mrs lr, spsr 1024 str lr, [sp, #8] @ save spsr 1025 1026 @ 1027 @ Prepare for SVC32 mode. IRQs remain disabled. 1028 @ 1029 mrs r0, cpsr 1030 eor r0, r0, #(\mode ^ SVC_MODE | PSR_ISETSTATE) 1031 msr spsr_cxsf, r0 1032 1033 @ 1034 @ the branch table must immediately follow this code 1035 @ 1036 and lr, lr, #0x0f 1037 THUMB( adr r0, 1f ) 1038 THUMB( ldr lr, [r0, lr, lsl #2] ) 1039 mov r0, sp 1040 ARM( ldr lr, [pc, lr, lsl #2] ) 1041 movs pc, lr @ branch to handler in SVC mode 1042ENDPROC(vector_\name) 1043 1044 .align 2 1045 @ handler addresses follow this label 10461: 1047 .endm 1048 1049 .section .stubs, "ax", %progbits 1050__stubs_start: 1051 @ This must be the first word 1052 .word vector_swi 1053 1054vector_rst: 1055 ARM( swi SYS_ERROR0 ) 1056 THUMB( svc #0 ) 1057 THUMB( nop ) 1058 b vector_und 1059 1060/* 1061 * Interrupt dispatcher 1062 */ 1063 vector_stub irq, IRQ_MODE, 4 1064 1065 .long __irq_usr @ 0 (USR_26 / USR_32) 1066 .long __irq_invalid @ 1 (FIQ_26 / FIQ_32) 1067 .long __irq_invalid @ 2 (IRQ_26 / IRQ_32) 1068 .long __irq_svc @ 3 (SVC_26 / SVC_32) 1069 .long __irq_invalid @ 4 1070 .long __irq_invalid @ 5 1071 .long __irq_invalid @ 6 1072 .long __irq_invalid @ 7 1073 .long __irq_invalid @ 8 1074 .long __irq_invalid @ 9 1075 .long __irq_invalid @ a 1076 .long __irq_invalid @ b 1077 .long __irq_invalid @ c 1078 .long __irq_invalid @ d 1079 .long __irq_invalid @ e 1080 .long __irq_invalid @ f 1081 1082/* 1083 * Data abort dispatcher 1084 * Enter in ABT mode, spsr = USR CPSR, lr = USR PC 1085 */ 1086 vector_stub dabt, ABT_MODE, 8 1087 1088 .long __dabt_usr @ 0 (USR_26 / USR_32) 1089 .long __dabt_invalid @ 1 (FIQ_26 / FIQ_32) 1090 .long __dabt_invalid @ 2 (IRQ_26 / IRQ_32) 1091 .long __dabt_svc @ 3 (SVC_26 / SVC_32) 1092 .long __dabt_invalid @ 4 1093 .long __dabt_invalid @ 5 1094 .long __dabt_invalid @ 6 1095 .long __dabt_invalid @ 7 1096 .long __dabt_invalid @ 8 1097 .long __dabt_invalid @ 9 1098 .long __dabt_invalid @ a 1099 .long __dabt_invalid @ b 1100 .long __dabt_invalid @ c 1101 .long __dabt_invalid @ d 1102 .long __dabt_invalid @ e 1103 .long __dabt_invalid @ f 1104 1105/* 1106 * Prefetch abort dispatcher 1107 * Enter in ABT mode, spsr = USR CPSR, lr = USR PC 1108 */ 1109 vector_stub pabt, ABT_MODE, 4 1110 1111 .long __pabt_usr @ 0 (USR_26 / USR_32) 1112 .long __pabt_invalid @ 1 (FIQ_26 / FIQ_32) 1113 .long __pabt_invalid @ 2 (IRQ_26 / IRQ_32) 1114 .long __pabt_svc @ 3 (SVC_26 / SVC_32) 1115 .long __pabt_invalid @ 4 1116 .long __pabt_invalid @ 5 1117 .long __pabt_invalid @ 6 1118 .long __pabt_invalid @ 7 1119 .long __pabt_invalid @ 8 1120 .long __pabt_invalid @ 9 1121 .long __pabt_invalid @ a 1122 .long __pabt_invalid @ b 1123 .long __pabt_invalid @ c 1124 .long __pabt_invalid @ d 1125 .long __pabt_invalid @ e 1126 .long __pabt_invalid @ f 1127 1128/* 1129 * Undef instr entry dispatcher 1130 * Enter in UND mode, spsr = SVC/USR CPSR, lr = SVC/USR PC 1131 */ 1132 vector_stub und, UND_MODE 1133 1134 .long __und_usr @ 0 (USR_26 / USR_32) 1135 .long __und_invalid @ 1 (FIQ_26 / FIQ_32) 1136 .long __und_invalid @ 2 (IRQ_26 / IRQ_32) 1137 .long __und_svc @ 3 (SVC_26 / SVC_32) 1138 .long __und_invalid @ 4 1139 .long __und_invalid @ 5 1140 .long __und_invalid @ 6 1141 .long __und_invalid @ 7 1142 .long __und_invalid @ 8 1143 .long __und_invalid @ 9 1144 .long __und_invalid @ a 1145 .long __und_invalid @ b 1146 .long __und_invalid @ c 1147 .long __und_invalid @ d 1148 .long __und_invalid @ e 1149 .long __und_invalid @ f 1150 1151 .align 5 1152 1153/*============================================================================= 1154 * Address exception handler 1155 *----------------------------------------------------------------------------- 1156 * These aren't too critical. 1157 * (they're not supposed to happen, and won't happen in 32-bit data mode). 1158 */ 1159 1160vector_addrexcptn: 1161 b vector_addrexcptn 1162 1163/*============================================================================= 1164 * Undefined FIQs 1165 *----------------------------------------------------------------------------- 1166 * Enter in FIQ mode, spsr = ANY CPSR, lr = ANY PC 1167 * MUST PRESERVE SVC SPSR, but need to switch to SVC mode to show our msg. 1168 * Basically to switch modes, we *HAVE* to clobber one register... brain 1169 * damage alert! I don't think that we can execute any code in here in any 1170 * other mode than FIQ... Ok you can switch to another mode, but you can't 1171 * get out of that mode without clobbering one register. 1172 */ 1173vector_fiq: 1174 subs pc, lr, #4 1175 1176 .globl vector_fiq_offset 1177 .equ vector_fiq_offset, vector_fiq 1178 1179 .section .vectors, "ax", %progbits 1180__vectors_start: 1181 W(b) vector_rst 1182 W(b) vector_und 1183 W(ldr) pc, __vectors_start + 0x1000 1184 W(b) vector_pabt 1185 W(b) vector_dabt 1186 W(b) vector_addrexcptn 1187 W(b) vector_irq 1188 W(b) vector_fiq 1189 1190 .data 1191 1192 .globl cr_alignment 1193 .globl cr_no_alignment 1194cr_alignment: 1195 .space 4 1196cr_no_alignment: 1197 .space 4 1198 1199#ifdef CONFIG_MULTI_IRQ_HANDLER 1200 .globl handle_arch_irq 1201handle_arch_irq: 1202 .space 4 1203#endif 1204