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 THUMB( ldr r5, [sp, #S_PSR] ) @ potentially updated CPSR 196 svc_exit r5 @ return from exception 197 UNWIND(.fnend ) 198ENDPROC(__dabt_svc) 199 200 .align 5 201__irq_svc: 202 svc_entry 203 irq_handler 204 205#ifdef CONFIG_PREEMPT 206 get_thread_info tsk 207 ldr r8, [tsk, #TI_PREEMPT] @ get preempt count 208 ldr r0, [tsk, #TI_FLAGS] @ get flags 209 teq r8, #0 @ if preempt count != 0 210 movne r0, #0 @ force flags to 0 211 tst r0, #_TIF_NEED_RESCHED 212 blne svc_preempt 213#endif 214 215 svc_exit r5, irq = 1 @ return from exception 216 UNWIND(.fnend ) 217ENDPROC(__irq_svc) 218 219 .ltorg 220 221#ifdef CONFIG_PREEMPT 222svc_preempt: 223 mov r8, lr 2241: bl preempt_schedule_irq @ irq en/disable is done inside 225 ldr r0, [tsk, #TI_FLAGS] @ get new tasks TI_FLAGS 226 tst r0, #_TIF_NEED_RESCHED 227 moveq pc, r8 @ go again 228 b 1b 229#endif 230 231__und_fault: 232 @ Correct the PC such that it is pointing at the instruction 233 @ which caused the fault. If the faulting instruction was ARM 234 @ the PC will be pointing at the next instruction, and have to 235 @ subtract 4. Otherwise, it is Thumb, and the PC will be 236 @ pointing at the second half of the Thumb instruction. We 237 @ have to subtract 2. 238 ldr r2, [r0, #S_PC] 239 sub r2, r2, r1 240 str r2, [r0, #S_PC] 241 b do_undefinstr 242ENDPROC(__und_fault) 243 244 .align 5 245__und_svc: 246#ifdef CONFIG_KPROBES 247 @ If a kprobe is about to simulate a "stmdb sp..." instruction, 248 @ it obviously needs free stack space which then will belong to 249 @ the saved context. 250 svc_entry 64 251#else 252 svc_entry 253#endif 254 @ 255 @ call emulation code, which returns using r9 if it has emulated 256 @ the instruction, or the more conventional lr if we are to treat 257 @ this as a real undefined instruction 258 @ 259 @ r0 - instruction 260 @ 261#ifndef CONFIG_THUMB2_KERNEL 262 ldr r0, [r4, #-4] 263#else 264 mov r1, #2 265 ldrh r0, [r4, #-2] @ Thumb instruction at LR - 2 266 cmp r0, #0xe800 @ 32-bit instruction if xx >= 0 267 blo __und_svc_fault 268 ldrh r9, [r4] @ bottom 16 bits 269 add r4, r4, #2 270 str r4, [sp, #S_PC] 271 orr r0, r9, r0, lsl #16 272#endif 273 adr r9, BSYM(__und_svc_finish) 274 mov r2, r4 275 bl call_fpe 276 277 mov r1, #4 @ PC correction to apply 278__und_svc_fault: 279 mov r0, sp @ struct pt_regs *regs 280 bl __und_fault 281 282__und_svc_finish: 283 ldr r5, [sp, #S_PSR] @ Get SVC cpsr 284 svc_exit r5 @ return from exception 285 UNWIND(.fnend ) 286ENDPROC(__und_svc) 287 288 .align 5 289__pabt_svc: 290 svc_entry 291 mov r2, sp @ regs 292 pabt_helper 293 svc_exit r5 @ return from exception 294 UNWIND(.fnend ) 295ENDPROC(__pabt_svc) 296 297 .align 5 298.LCcralign: 299 .word cr_alignment 300#ifdef MULTI_DABORT 301.LCprocfns: 302 .word processor 303#endif 304.LCfp: 305 .word fp_enter 306 307/* 308 * User mode handlers 309 * 310 * EABI note: sp_svc is always 64-bit aligned here, so should S_FRAME_SIZE 311 */ 312 313#if defined(CONFIG_AEABI) && (__LINUX_ARM_ARCH__ >= 5) && (S_FRAME_SIZE & 7) 314#error "sizeof(struct pt_regs) must be a multiple of 8" 315#endif 316 317 .macro usr_entry 318 UNWIND(.fnstart ) 319 UNWIND(.cantunwind ) @ don't unwind the user space 320 sub sp, sp, #S_FRAME_SIZE 321 ARM( stmib sp, {r1 - r12} ) 322 THUMB( stmia sp, {r0 - r12} ) 323 324 ldmia r0, {r3 - r5} 325 add r0, sp, #S_PC @ here for interlock avoidance 326 mov r6, #-1 @ "" "" "" "" 327 328 str r3, [sp] @ save the "real" r0 copied 329 @ from the exception stack 330 331 @ 332 @ We are now ready to fill in the remaining blanks on the stack: 333 @ 334 @ r4 - lr_<exception>, already fixed up for correct return/restart 335 @ r5 - spsr_<exception> 336 @ r6 - orig_r0 (see pt_regs definition in ptrace.h) 337 @ 338 @ Also, separately save sp_usr and lr_usr 339 @ 340 stmia r0, {r4 - r6} 341 ARM( stmdb r0, {sp, lr}^ ) 342 THUMB( store_user_sp_lr r0, r1, S_SP - S_PC ) 343 344 @ 345 @ Enable the alignment trap while in kernel mode 346 @ 347 alignment_trap r0 348 349 @ 350 @ Clear FP to mark the first stack frame 351 @ 352 zero_fp 353 354#ifdef CONFIG_IRQSOFF_TRACER 355 bl trace_hardirqs_off 356#endif 357 ct_user_exit save = 0 358 .endm 359 360 .macro kuser_cmpxchg_check 361#if !defined(CONFIG_CPU_32v6K) && defined(CONFIG_KUSER_HELPERS) && \ 362 !defined(CONFIG_NEEDS_SYSCALL_FOR_CMPXCHG) 363#ifndef CONFIG_MMU 364#warning "NPTL on non MMU needs fixing" 365#else 366 @ Make sure our user space atomic helper is restarted 367 @ if it was interrupted in a critical region. Here we 368 @ perform a quick test inline since it should be false 369 @ 99.9999% of the time. The rest is done out of line. 370 cmp r4, #TASK_SIZE 371 blhs kuser_cmpxchg64_fixup 372#endif 373#endif 374 .endm 375 376 .align 5 377__dabt_usr: 378 usr_entry 379 kuser_cmpxchg_check 380 mov r2, sp 381 dabt_helper 382 b ret_from_exception 383 UNWIND(.fnend ) 384ENDPROC(__dabt_usr) 385 386 .align 5 387__irq_usr: 388 usr_entry 389 kuser_cmpxchg_check 390 irq_handler 391 get_thread_info tsk 392 mov why, #0 393 b ret_to_user_from_irq 394 UNWIND(.fnend ) 395ENDPROC(__irq_usr) 396 397 .ltorg 398 399 .align 5 400__und_usr: 401 usr_entry 402 403 mov r2, r4 404 mov r3, r5 405 406 @ r2 = regs->ARM_pc, which is either 2 or 4 bytes ahead of the 407 @ faulting instruction depending on Thumb mode. 408 @ r3 = regs->ARM_cpsr 409 @ 410 @ The emulation code returns using r9 if it has emulated the 411 @ instruction, or the more conventional lr if we are to treat 412 @ this as a real undefined instruction 413 @ 414 adr r9, BSYM(ret_from_exception) 415 416 @ IRQs must be enabled before attempting to read the instruction from 417 @ user space since that could cause a page/translation fault if the 418 @ page table was modified by another CPU. 419 enable_irq 420 421 tst r3, #PSR_T_BIT @ Thumb mode? 422 bne __und_usr_thumb 423 sub r4, r2, #4 @ ARM instr at LR - 4 4241: ldrt r0, [r4] 425 ARM_BE8(rev r0, r0) @ little endian instruction 426 427 @ r0 = 32-bit ARM instruction which caused the exception 428 @ r2 = PC value for the following instruction (:= regs->ARM_pc) 429 @ r4 = PC value for the faulting instruction 430 @ lr = 32-bit undefined instruction function 431 adr lr, BSYM(__und_usr_fault_32) 432 b call_fpe 433 434__und_usr_thumb: 435 @ Thumb instruction 436 sub r4, r2, #2 @ First half of thumb instr at LR - 2 437#if CONFIG_ARM_THUMB && __LINUX_ARM_ARCH__ >= 6 && CONFIG_CPU_V7 438/* 439 * Thumb-2 instruction handling. Note that because pre-v6 and >= v6 platforms 440 * can never be supported in a single kernel, this code is not applicable at 441 * all when __LINUX_ARM_ARCH__ < 6. This allows simplifying assumptions to be 442 * made about .arch directives. 443 */ 444#if __LINUX_ARM_ARCH__ < 7 445/* If the target CPU may not be Thumb-2-capable, a run-time check is needed: */ 446#define NEED_CPU_ARCHITECTURE 447 ldr r5, .LCcpu_architecture 448 ldr r5, [r5] 449 cmp r5, #CPU_ARCH_ARMv7 450 blo __und_usr_fault_16 @ 16bit undefined instruction 451/* 452 * The following code won't get run unless the running CPU really is v7, so 453 * coding round the lack of ldrht on older arches is pointless. Temporarily 454 * override the assembler target arch with the minimum required instead: 455 */ 456 .arch armv6t2 457#endif 4582: ldrht r5, [r4] 459ARM_BE8(rev16 r5, r5) @ little endian instruction 460 cmp r5, #0xe800 @ 32bit instruction if xx != 0 461 blo __und_usr_fault_16 @ 16bit undefined instruction 4623: ldrht r0, [r2] 463ARM_BE8(rev16 r0, r0) @ little endian instruction 464 add r2, r2, #2 @ r2 is PC + 2, make it PC + 4 465 str r2, [sp, #S_PC] @ it's a 2x16bit instr, update 466 orr r0, r0, r5, lsl #16 467 adr lr, BSYM(__und_usr_fault_32) 468 @ r0 = the two 16-bit Thumb instructions which caused the exception 469 @ r2 = PC value for the following Thumb instruction (:= regs->ARM_pc) 470 @ r4 = PC value for the first 16-bit Thumb instruction 471 @ lr = 32bit undefined instruction function 472 473#if __LINUX_ARM_ARCH__ < 7 474/* If the target arch was overridden, change it back: */ 475#ifdef CONFIG_CPU_32v6K 476 .arch armv6k 477#else 478 .arch armv6 479#endif 480#endif /* __LINUX_ARM_ARCH__ < 7 */ 481#else /* !(CONFIG_ARM_THUMB && __LINUX_ARM_ARCH__ >= 6 && CONFIG_CPU_V7) */ 482 b __und_usr_fault_16 483#endif 484 UNWIND(.fnend) 485ENDPROC(__und_usr) 486 487/* 488 * The out of line fixup for the ldrt instructions above. 489 */ 490 .pushsection .fixup, "ax" 491 .align 2 4924: str r4, [sp, #S_PC] @ retry current instruction 493 mov pc, r9 494 .popsection 495 .pushsection __ex_table,"a" 496 .long 1b, 4b 497#if CONFIG_ARM_THUMB && __LINUX_ARM_ARCH__ >= 6 && CONFIG_CPU_V7 498 .long 2b, 4b 499 .long 3b, 4b 500#endif 501 .popsection 502 503/* 504 * Check whether the instruction is a co-processor instruction. 505 * If yes, we need to call the relevant co-processor handler. 506 * 507 * Note that we don't do a full check here for the co-processor 508 * instructions; all instructions with bit 27 set are well 509 * defined. The only instructions that should fault are the 510 * co-processor instructions. However, we have to watch out 511 * for the ARM6/ARM7 SWI bug. 512 * 513 * NEON is a special case that has to be handled here. Not all 514 * NEON instructions are co-processor instructions, so we have 515 * to make a special case of checking for them. Plus, there's 516 * five groups of them, so we have a table of mask/opcode pairs 517 * to check against, and if any match then we branch off into the 518 * NEON handler code. 519 * 520 * Emulators may wish to make use of the following registers: 521 * r0 = instruction opcode (32-bit ARM or two 16-bit Thumb) 522 * r2 = PC value to resume execution after successful emulation 523 * r9 = normal "successful" return address 524 * r10 = this threads thread_info structure 525 * lr = unrecognised instruction return address 526 * IRQs enabled, FIQs enabled. 527 */ 528 @ 529 @ Fall-through from Thumb-2 __und_usr 530 @ 531#ifdef CONFIG_NEON 532 get_thread_info r10 @ get current thread 533 adr r6, .LCneon_thumb_opcodes 534 b 2f 535#endif 536call_fpe: 537 get_thread_info r10 @ get current thread 538#ifdef CONFIG_NEON 539 adr r6, .LCneon_arm_opcodes 5402: ldr r5, [r6], #4 @ mask value 541 ldr r7, [r6], #4 @ opcode bits matching in mask 542 cmp r5, #0 @ end mask? 543 beq 1f 544 and r8, r0, r5 545 cmp r8, r7 @ NEON instruction? 546 bne 2b 547 mov r7, #1 548 strb r7, [r10, #TI_USED_CP + 10] @ mark CP#10 as used 549 strb r7, [r10, #TI_USED_CP + 11] @ mark CP#11 as used 550 b do_vfp @ let VFP handler handle this 5511: 552#endif 553 tst r0, #0x08000000 @ only CDP/CPRT/LDC/STC have bit 27 554 tstne r0, #0x04000000 @ bit 26 set on both ARM and Thumb-2 555 moveq pc, lr 556 and r8, r0, #0x00000f00 @ mask out CP number 557 THUMB( lsr r8, r8, #8 ) 558 mov r7, #1 559 add r6, r10, #TI_USED_CP 560 ARM( strb r7, [r6, r8, lsr #8] ) @ set appropriate used_cp[] 561 THUMB( strb r7, [r6, r8] ) @ set appropriate used_cp[] 562#ifdef CONFIG_IWMMXT 563 @ Test if we need to give access to iWMMXt coprocessors 564 ldr r5, [r10, #TI_FLAGS] 565 rsbs r7, r8, #(1 << 8) @ CP 0 or 1 only 566 movcss r7, r5, lsr #(TIF_USING_IWMMXT + 1) 567 bcs iwmmxt_task_enable 568#endif 569 ARM( add pc, pc, r8, lsr #6 ) 570 THUMB( lsl r8, r8, #2 ) 571 THUMB( add pc, r8 ) 572 nop 573 574 movw_pc lr @ CP#0 575 W(b) do_fpe @ CP#1 (FPE) 576 W(b) do_fpe @ CP#2 (FPE) 577 movw_pc lr @ CP#3 578#ifdef CONFIG_CRUNCH 579 b crunch_task_enable @ CP#4 (MaverickCrunch) 580 b crunch_task_enable @ CP#5 (MaverickCrunch) 581 b crunch_task_enable @ CP#6 (MaverickCrunch) 582#else 583 movw_pc lr @ CP#4 584 movw_pc lr @ CP#5 585 movw_pc lr @ CP#6 586#endif 587 movw_pc lr @ CP#7 588 movw_pc lr @ CP#8 589 movw_pc lr @ CP#9 590#ifdef CONFIG_VFP 591 W(b) do_vfp @ CP#10 (VFP) 592 W(b) do_vfp @ CP#11 (VFP) 593#else 594 movw_pc lr @ CP#10 (VFP) 595 movw_pc lr @ CP#11 (VFP) 596#endif 597 movw_pc lr @ CP#12 598 movw_pc lr @ CP#13 599 movw_pc lr @ CP#14 (Debug) 600 movw_pc lr @ CP#15 (Control) 601 602#ifdef NEED_CPU_ARCHITECTURE 603 .align 2 604.LCcpu_architecture: 605 .word __cpu_architecture 606#endif 607 608#ifdef CONFIG_NEON 609 .align 6 610 611.LCneon_arm_opcodes: 612 .word 0xfe000000 @ mask 613 .word 0xf2000000 @ opcode 614 615 .word 0xff100000 @ mask 616 .word 0xf4000000 @ opcode 617 618 .word 0x00000000 @ mask 619 .word 0x00000000 @ opcode 620 621.LCneon_thumb_opcodes: 622 .word 0xef000000 @ mask 623 .word 0xef000000 @ opcode 624 625 .word 0xff100000 @ mask 626 .word 0xf9000000 @ opcode 627 628 .word 0x00000000 @ mask 629 .word 0x00000000 @ opcode 630#endif 631 632do_fpe: 633 ldr r4, .LCfp 634 add r10, r10, #TI_FPSTATE @ r10 = workspace 635 ldr pc, [r4] @ Call FP module USR entry point 636 637/* 638 * The FP module is called with these registers set: 639 * r0 = instruction 640 * r2 = PC+4 641 * r9 = normal "successful" return address 642 * r10 = FP workspace 643 * lr = unrecognised FP instruction return address 644 */ 645 646 .pushsection .data 647ENTRY(fp_enter) 648 .word no_fp 649 .popsection 650 651ENTRY(no_fp) 652 mov pc, lr 653ENDPROC(no_fp) 654 655__und_usr_fault_32: 656 mov r1, #4 657 b 1f 658__und_usr_fault_16: 659 mov r1, #2 6601: mov r0, sp 661 adr lr, BSYM(ret_from_exception) 662 b __und_fault 663ENDPROC(__und_usr_fault_32) 664ENDPROC(__und_usr_fault_16) 665 666 .align 5 667__pabt_usr: 668 usr_entry 669 mov r2, sp @ regs 670 pabt_helper 671 UNWIND(.fnend ) 672 /* fall through */ 673/* 674 * This is the return code to user mode for abort handlers 675 */ 676ENTRY(ret_from_exception) 677 UNWIND(.fnstart ) 678 UNWIND(.cantunwind ) 679 get_thread_info tsk 680 mov why, #0 681 b ret_to_user 682 UNWIND(.fnend ) 683ENDPROC(__pabt_usr) 684ENDPROC(ret_from_exception) 685 686/* 687 * Register switch for ARMv3 and ARMv4 processors 688 * r0 = previous task_struct, r1 = previous thread_info, r2 = next thread_info 689 * previous and next are guaranteed not to be the same. 690 */ 691ENTRY(__switch_to) 692 UNWIND(.fnstart ) 693 UNWIND(.cantunwind ) 694 add ip, r1, #TI_CPU_SAVE 695 ARM( stmia ip!, {r4 - sl, fp, sp, lr} ) @ Store most regs on stack 696 THUMB( stmia ip!, {r4 - sl, fp} ) @ Store most regs on stack 697 THUMB( str sp, [ip], #4 ) 698 THUMB( str lr, [ip], #4 ) 699 ldr r4, [r2, #TI_TP_VALUE] 700 ldr r5, [r2, #TI_TP_VALUE + 4] 701#ifdef CONFIG_CPU_USE_DOMAINS 702 ldr r6, [r2, #TI_CPU_DOMAIN] 703#endif 704 switch_tls r1, r4, r5, r3, r7 705#if defined(CONFIG_CC_STACKPROTECTOR) && !defined(CONFIG_SMP) 706 ldr r7, [r2, #TI_TASK] 707 ldr r8, =__stack_chk_guard 708 ldr r7, [r7, #TSK_STACK_CANARY] 709#endif 710#ifdef CONFIG_CPU_USE_DOMAINS 711 mcr p15, 0, r6, c3, c0, 0 @ Set domain register 712#endif 713 mov r5, r0 714 add r4, r2, #TI_CPU_SAVE 715 ldr r0, =thread_notify_head 716 mov r1, #THREAD_NOTIFY_SWITCH 717 bl atomic_notifier_call_chain 718#if defined(CONFIG_CC_STACKPROTECTOR) && !defined(CONFIG_SMP) 719 str r7, [r8] 720#endif 721 THUMB( mov ip, r4 ) 722 mov r0, r5 723 ARM( ldmia r4, {r4 - sl, fp, sp, pc} ) @ Load all regs saved previously 724 THUMB( ldmia ip!, {r4 - sl, fp} ) @ Load all regs saved previously 725 THUMB( ldr sp, [ip], #4 ) 726 THUMB( ldr pc, [ip] ) 727 UNWIND(.fnend ) 728ENDPROC(__switch_to) 729 730 __INIT 731 732/* 733 * User helpers. 734 * 735 * Each segment is 32-byte aligned and will be moved to the top of the high 736 * vector page. New segments (if ever needed) must be added in front of 737 * existing ones. This mechanism should be used only for things that are 738 * really small and justified, and not be abused freely. 739 * 740 * See Documentation/arm/kernel_user_helpers.txt for formal definitions. 741 */ 742 THUMB( .arm ) 743 744 .macro usr_ret, reg 745#ifdef CONFIG_ARM_THUMB 746 bx \reg 747#else 748 mov pc, \reg 749#endif 750 .endm 751 752 .macro kuser_pad, sym, size 753 .if (. - \sym) & 3 754 .rept 4 - (. - \sym) & 3 755 .byte 0 756 .endr 757 .endif 758 .rept (\size - (. - \sym)) / 4 759 .word 0xe7fddef1 760 .endr 761 .endm 762 763#ifdef CONFIG_KUSER_HELPERS 764 .align 5 765 .globl __kuser_helper_start 766__kuser_helper_start: 767 768/* 769 * Due to the length of some sequences, __kuser_cmpxchg64 spans 2 regular 770 * kuser "slots", therefore 0xffff0f80 is not used as a valid entry point. 771 */ 772 773__kuser_cmpxchg64: @ 0xffff0f60 774 775#if defined(CONFIG_NEEDS_SYSCALL_FOR_CMPXCHG) 776 777 /* 778 * Poor you. No fast solution possible... 779 * The kernel itself must perform the operation. 780 * A special ghost syscall is used for that (see traps.c). 781 */ 782 stmfd sp!, {r7, lr} 783 ldr r7, 1f @ it's 20 bits 784 swi __ARM_NR_cmpxchg64 785 ldmfd sp!, {r7, pc} 7861: .word __ARM_NR_cmpxchg64 787 788#elif defined(CONFIG_CPU_32v6K) 789 790 stmfd sp!, {r4, r5, r6, r7} 791 ldrd r4, r5, [r0] @ load old val 792 ldrd r6, r7, [r1] @ load new val 793 smp_dmb arm 7941: ldrexd r0, r1, [r2] @ load current val 795 eors r3, r0, r4 @ compare with oldval (1) 796 eoreqs r3, r1, r5 @ compare with oldval (2) 797 strexdeq r3, r6, r7, [r2] @ store newval if eq 798 teqeq r3, #1 @ success? 799 beq 1b @ if no then retry 800 smp_dmb arm 801 rsbs r0, r3, #0 @ set returned val and C flag 802 ldmfd sp!, {r4, r5, r6, r7} 803 usr_ret lr 804 805#elif !defined(CONFIG_SMP) 806 807#ifdef CONFIG_MMU 808 809 /* 810 * The only thing that can break atomicity in this cmpxchg64 811 * implementation is either an IRQ or a data abort exception 812 * causing another process/thread to be scheduled in the middle of 813 * the critical sequence. The same strategy as for cmpxchg is used. 814 */ 815 stmfd sp!, {r4, r5, r6, lr} 816 ldmia r0, {r4, r5} @ load old val 817 ldmia r1, {r6, lr} @ load new val 8181: ldmia r2, {r0, r1} @ load current val 819 eors r3, r0, r4 @ compare with oldval (1) 820 eoreqs r3, r1, r5 @ compare with oldval (2) 8212: stmeqia r2, {r6, lr} @ store newval if eq 822 rsbs r0, r3, #0 @ set return val and C flag 823 ldmfd sp!, {r4, r5, r6, pc} 824 825 .text 826kuser_cmpxchg64_fixup: 827 @ Called from kuser_cmpxchg_fixup. 828 @ r4 = address of interrupted insn (must be preserved). 829 @ sp = saved regs. r7 and r8 are clobbered. 830 @ 1b = first critical insn, 2b = last critical insn. 831 @ If r4 >= 1b and r4 <= 2b then saved pc_usr is set to 1b. 832 mov r7, #0xffff0fff 833 sub r7, r7, #(0xffff0fff - (0xffff0f60 + (1b - __kuser_cmpxchg64))) 834 subs r8, r4, r7 835 rsbcss r8, r8, #(2b - 1b) 836 strcs r7, [sp, #S_PC] 837#if __LINUX_ARM_ARCH__ < 6 838 bcc kuser_cmpxchg32_fixup 839#endif 840 mov pc, lr 841 .previous 842 843#else 844#warning "NPTL on non MMU needs fixing" 845 mov r0, #-1 846 adds r0, r0, #0 847 usr_ret lr 848#endif 849 850#else 851#error "incoherent kernel configuration" 852#endif 853 854 kuser_pad __kuser_cmpxchg64, 64 855 856__kuser_memory_barrier: @ 0xffff0fa0 857 smp_dmb arm 858 usr_ret lr 859 860 kuser_pad __kuser_memory_barrier, 32 861 862__kuser_cmpxchg: @ 0xffff0fc0 863 864#if defined(CONFIG_NEEDS_SYSCALL_FOR_CMPXCHG) 865 866 /* 867 * Poor you. No fast solution possible... 868 * The kernel itself must perform the operation. 869 * A special ghost syscall is used for that (see traps.c). 870 */ 871 stmfd sp!, {r7, lr} 872 ldr r7, 1f @ it's 20 bits 873 swi __ARM_NR_cmpxchg 874 ldmfd sp!, {r7, pc} 8751: .word __ARM_NR_cmpxchg 876 877#elif __LINUX_ARM_ARCH__ < 6 878 879#ifdef CONFIG_MMU 880 881 /* 882 * The only thing that can break atomicity in this cmpxchg 883 * implementation is either an IRQ or a data abort exception 884 * causing another process/thread to be scheduled in the middle 885 * of the critical sequence. To prevent this, code is added to 886 * the IRQ and data abort exception handlers to set the pc back 887 * to the beginning of the critical section if it is found to be 888 * within that critical section (see kuser_cmpxchg_fixup). 889 */ 8901: ldr r3, [r2] @ load current val 891 subs r3, r3, r0 @ compare with oldval 8922: streq r1, [r2] @ store newval if eq 893 rsbs r0, r3, #0 @ set return val and C flag 894 usr_ret lr 895 896 .text 897kuser_cmpxchg32_fixup: 898 @ Called from kuser_cmpxchg_check macro. 899 @ r4 = address of interrupted insn (must be preserved). 900 @ sp = saved regs. r7 and r8 are clobbered. 901 @ 1b = first critical insn, 2b = last critical insn. 902 @ If r4 >= 1b and r4 <= 2b then saved pc_usr is set to 1b. 903 mov r7, #0xffff0fff 904 sub r7, r7, #(0xffff0fff - (0xffff0fc0 + (1b - __kuser_cmpxchg))) 905 subs r8, r4, r7 906 rsbcss r8, r8, #(2b - 1b) 907 strcs r7, [sp, #S_PC] 908 mov pc, lr 909 .previous 910 911#else 912#warning "NPTL on non MMU needs fixing" 913 mov r0, #-1 914 adds r0, r0, #0 915 usr_ret lr 916#endif 917 918#else 919 920 smp_dmb arm 9211: ldrex r3, [r2] 922 subs r3, r3, r0 923 strexeq r3, r1, [r2] 924 teqeq r3, #1 925 beq 1b 926 rsbs r0, r3, #0 927 /* beware -- each __kuser slot must be 8 instructions max */ 928 ALT_SMP(b __kuser_memory_barrier) 929 ALT_UP(usr_ret lr) 930 931#endif 932 933 kuser_pad __kuser_cmpxchg, 32 934 935__kuser_get_tls: @ 0xffff0fe0 936 ldr r0, [pc, #(16 - 8)] @ read TLS, set in kuser_get_tls_init 937 usr_ret lr 938 mrc p15, 0, r0, c13, c0, 3 @ 0xffff0fe8 hardware TLS code 939 kuser_pad __kuser_get_tls, 16 940 .rep 3 941 .word 0 @ 0xffff0ff0 software TLS value, then 942 .endr @ pad up to __kuser_helper_version 943 944__kuser_helper_version: @ 0xffff0ffc 945 .word ((__kuser_helper_end - __kuser_helper_start) >> 5) 946 947 .globl __kuser_helper_end 948__kuser_helper_end: 949 950#endif 951 952 THUMB( .thumb ) 953 954/* 955 * Vector stubs. 956 * 957 * This code is copied to 0xffff1000 so we can use branches in the 958 * vectors, rather than ldr's. Note that this code must not exceed 959 * a page size. 960 * 961 * Common stub entry macro: 962 * Enter in IRQ mode, spsr = SVC/USR CPSR, lr = SVC/USR PC 963 * 964 * SP points to a minimal amount of processor-private memory, the address 965 * of which is copied into r0 for the mode specific abort handler. 966 */ 967 .macro vector_stub, name, mode, correction=0 968 .align 5 969 970vector_\name: 971 .if \correction 972 sub lr, lr, #\correction 973 .endif 974 975 @ 976 @ Save r0, lr_<exception> (parent PC) and spsr_<exception> 977 @ (parent CPSR) 978 @ 979 stmia sp, {r0, lr} @ save r0, lr 980 mrs lr, spsr 981 str lr, [sp, #8] @ save spsr 982 983 @ 984 @ Prepare for SVC32 mode. IRQs remain disabled. 985 @ 986 mrs r0, cpsr 987 eor r0, r0, #(\mode ^ SVC_MODE | PSR_ISETSTATE) 988 msr spsr_cxsf, r0 989 990 @ 991 @ the branch table must immediately follow this code 992 @ 993 and lr, lr, #0x0f 994 THUMB( adr r0, 1f ) 995 THUMB( ldr lr, [r0, lr, lsl #2] ) 996 mov r0, sp 997 ARM( ldr lr, [pc, lr, lsl #2] ) 998 movs pc, lr @ branch to handler in SVC mode 999ENDPROC(vector_\name) 1000 1001 .align 2 1002 @ handler addresses follow this label 10031: 1004 .endm 1005 1006 .section .stubs, "ax", %progbits 1007__stubs_start: 1008 @ This must be the first word 1009 .word vector_swi 1010 1011vector_rst: 1012 ARM( swi SYS_ERROR0 ) 1013 THUMB( svc #0 ) 1014 THUMB( nop ) 1015 b vector_und 1016 1017/* 1018 * Interrupt dispatcher 1019 */ 1020 vector_stub irq, IRQ_MODE, 4 1021 1022 .long __irq_usr @ 0 (USR_26 / USR_32) 1023 .long __irq_invalid @ 1 (FIQ_26 / FIQ_32) 1024 .long __irq_invalid @ 2 (IRQ_26 / IRQ_32) 1025 .long __irq_svc @ 3 (SVC_26 / SVC_32) 1026 .long __irq_invalid @ 4 1027 .long __irq_invalid @ 5 1028 .long __irq_invalid @ 6 1029 .long __irq_invalid @ 7 1030 .long __irq_invalid @ 8 1031 .long __irq_invalid @ 9 1032 .long __irq_invalid @ a 1033 .long __irq_invalid @ b 1034 .long __irq_invalid @ c 1035 .long __irq_invalid @ d 1036 .long __irq_invalid @ e 1037 .long __irq_invalid @ f 1038 1039/* 1040 * Data abort dispatcher 1041 * Enter in ABT mode, spsr = USR CPSR, lr = USR PC 1042 */ 1043 vector_stub dabt, ABT_MODE, 8 1044 1045 .long __dabt_usr @ 0 (USR_26 / USR_32) 1046 .long __dabt_invalid @ 1 (FIQ_26 / FIQ_32) 1047 .long __dabt_invalid @ 2 (IRQ_26 / IRQ_32) 1048 .long __dabt_svc @ 3 (SVC_26 / SVC_32) 1049 .long __dabt_invalid @ 4 1050 .long __dabt_invalid @ 5 1051 .long __dabt_invalid @ 6 1052 .long __dabt_invalid @ 7 1053 .long __dabt_invalid @ 8 1054 .long __dabt_invalid @ 9 1055 .long __dabt_invalid @ a 1056 .long __dabt_invalid @ b 1057 .long __dabt_invalid @ c 1058 .long __dabt_invalid @ d 1059 .long __dabt_invalid @ e 1060 .long __dabt_invalid @ f 1061 1062/* 1063 * Prefetch abort dispatcher 1064 * Enter in ABT mode, spsr = USR CPSR, lr = USR PC 1065 */ 1066 vector_stub pabt, ABT_MODE, 4 1067 1068 .long __pabt_usr @ 0 (USR_26 / USR_32) 1069 .long __pabt_invalid @ 1 (FIQ_26 / FIQ_32) 1070 .long __pabt_invalid @ 2 (IRQ_26 / IRQ_32) 1071 .long __pabt_svc @ 3 (SVC_26 / SVC_32) 1072 .long __pabt_invalid @ 4 1073 .long __pabt_invalid @ 5 1074 .long __pabt_invalid @ 6 1075 .long __pabt_invalid @ 7 1076 .long __pabt_invalid @ 8 1077 .long __pabt_invalid @ 9 1078 .long __pabt_invalid @ a 1079 .long __pabt_invalid @ b 1080 .long __pabt_invalid @ c 1081 .long __pabt_invalid @ d 1082 .long __pabt_invalid @ e 1083 .long __pabt_invalid @ f 1084 1085/* 1086 * Undef instr entry dispatcher 1087 * Enter in UND mode, spsr = SVC/USR CPSR, lr = SVC/USR PC 1088 */ 1089 vector_stub und, UND_MODE 1090 1091 .long __und_usr @ 0 (USR_26 / USR_32) 1092 .long __und_invalid @ 1 (FIQ_26 / FIQ_32) 1093 .long __und_invalid @ 2 (IRQ_26 / IRQ_32) 1094 .long __und_svc @ 3 (SVC_26 / SVC_32) 1095 .long __und_invalid @ 4 1096 .long __und_invalid @ 5 1097 .long __und_invalid @ 6 1098 .long __und_invalid @ 7 1099 .long __und_invalid @ 8 1100 .long __und_invalid @ 9 1101 .long __und_invalid @ a 1102 .long __und_invalid @ b 1103 .long __und_invalid @ c 1104 .long __und_invalid @ d 1105 .long __und_invalid @ e 1106 .long __und_invalid @ f 1107 1108 .align 5 1109 1110/*============================================================================= 1111 * Address exception handler 1112 *----------------------------------------------------------------------------- 1113 * These aren't too critical. 1114 * (they're not supposed to happen, and won't happen in 32-bit data mode). 1115 */ 1116 1117vector_addrexcptn: 1118 b vector_addrexcptn 1119 1120/*============================================================================= 1121 * Undefined FIQs 1122 *----------------------------------------------------------------------------- 1123 * Enter in FIQ mode, spsr = ANY CPSR, lr = ANY PC 1124 * MUST PRESERVE SVC SPSR, but need to switch to SVC mode to show our msg. 1125 * Basically to switch modes, we *HAVE* to clobber one register... brain 1126 * damage alert! I don't think that we can execute any code in here in any 1127 * other mode than FIQ... Ok you can switch to another mode, but you can't 1128 * get out of that mode without clobbering one register. 1129 */ 1130vector_fiq: 1131 subs pc, lr, #4 1132 1133 .globl vector_fiq_offset 1134 .equ vector_fiq_offset, vector_fiq 1135 1136 .section .vectors, "ax", %progbits 1137__vectors_start: 1138 W(b) vector_rst 1139 W(b) vector_und 1140 W(ldr) pc, __vectors_start + 0x1000 1141 W(b) vector_pabt 1142 W(b) vector_dabt 1143 W(b) vector_addrexcptn 1144 W(b) vector_irq 1145 W(b) vector_fiq 1146 1147 .data 1148 1149 .globl cr_alignment 1150 .globl cr_no_alignment 1151cr_alignment: 1152 .space 4 1153cr_no_alignment: 1154 .space 4 1155 1156#ifdef CONFIG_MULTI_IRQ_HANDLER 1157 .globl handle_arch_irq 1158handle_arch_irq: 1159 .space 4 1160#endif 1161