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 svc_exit r5 @ return from exception 196 UNWIND(.fnend ) 197ENDPROC(__dabt_svc) 198 199 .align 5 200__irq_svc: 201 svc_entry 202 irq_handler 203 204#ifdef CONFIG_PREEMPT 205 get_thread_info tsk 206 ldr r8, [tsk, #TI_PREEMPT] @ get preempt count 207 ldr r0, [tsk, #TI_FLAGS] @ get flags 208 teq r8, #0 @ if preempt count != 0 209 movne r0, #0 @ force flags to 0 210 tst r0, #_TIF_NEED_RESCHED 211 blne svc_preempt 212#endif 213 214 svc_exit r5, irq = 1 @ return from exception 215 UNWIND(.fnend ) 216ENDPROC(__irq_svc) 217 218 .ltorg 219 220#ifdef CONFIG_PREEMPT 221svc_preempt: 222 mov r8, lr 2231: bl preempt_schedule_irq @ irq en/disable is done inside 224 ldr r0, [tsk, #TI_FLAGS] @ get new tasks TI_FLAGS 225 tst r0, #_TIF_NEED_RESCHED 226 moveq pc, r8 @ go again 227 b 1b 228#endif 229 230__und_fault: 231 @ Correct the PC such that it is pointing at the instruction 232 @ which caused the fault. If the faulting instruction was ARM 233 @ the PC will be pointing at the next instruction, and have to 234 @ subtract 4. Otherwise, it is Thumb, and the PC will be 235 @ pointing at the second half of the Thumb instruction. We 236 @ have to subtract 2. 237 ldr r2, [r0, #S_PC] 238 sub r2, r2, r1 239 str r2, [r0, #S_PC] 240 b do_undefinstr 241ENDPROC(__und_fault) 242 243 .align 5 244__und_svc: 245#ifdef CONFIG_KPROBES 246 @ If a kprobe is about to simulate a "stmdb sp..." instruction, 247 @ it obviously needs free stack space which then will belong to 248 @ the saved context. 249 svc_entry 64 250#else 251 svc_entry 252#endif 253 @ 254 @ call emulation code, which returns using r9 if it has emulated 255 @ the instruction, or the more conventional lr if we are to treat 256 @ this as a real undefined instruction 257 @ 258 @ r0 - instruction 259 @ 260#ifndef CONFIG_THUMB2_KERNEL 261 ldr r0, [r4, #-4] 262#else 263 mov r1, #2 264 ldrh r0, [r4, #-2] @ Thumb instruction at LR - 2 265 cmp r0, #0xe800 @ 32-bit instruction if xx >= 0 266 blo __und_svc_fault 267 ldrh r9, [r4] @ bottom 16 bits 268 add r4, r4, #2 269 str r4, [sp, #S_PC] 270 orr r0, r9, r0, lsl #16 271#endif 272 adr r9, BSYM(__und_svc_finish) 273 mov r2, r4 274 bl call_fpe 275 276 mov r1, #4 @ PC correction to apply 277__und_svc_fault: 278 mov r0, sp @ struct pt_regs *regs 279 bl __und_fault 280 281__und_svc_finish: 282 ldr r5, [sp, #S_PSR] @ Get SVC cpsr 283 svc_exit r5 @ return from exception 284 UNWIND(.fnend ) 285ENDPROC(__und_svc) 286 287 .align 5 288__pabt_svc: 289 svc_entry 290 mov r2, sp @ regs 291 pabt_helper 292 svc_exit r5 @ return from exception 293 UNWIND(.fnend ) 294ENDPROC(__pabt_svc) 295 296 .align 5 297.LCcralign: 298 .word cr_alignment 299#ifdef MULTI_DABORT 300.LCprocfns: 301 .word processor 302#endif 303.LCfp: 304 .word fp_enter 305 306/* 307 * User mode handlers 308 * 309 * EABI note: sp_svc is always 64-bit aligned here, so should S_FRAME_SIZE 310 */ 311 312#if defined(CONFIG_AEABI) && (__LINUX_ARM_ARCH__ >= 5) && (S_FRAME_SIZE & 7) 313#error "sizeof(struct pt_regs) must be a multiple of 8" 314#endif 315 316 .macro usr_entry 317 UNWIND(.fnstart ) 318 UNWIND(.cantunwind ) @ don't unwind the user space 319 sub sp, sp, #S_FRAME_SIZE 320 ARM( stmib sp, {r1 - r12} ) 321 THUMB( stmia sp, {r0 - r12} ) 322 323 ldmia r0, {r3 - r5} 324 add r0, sp, #S_PC @ here for interlock avoidance 325 mov r6, #-1 @ "" "" "" "" 326 327 str r3, [sp] @ save the "real" r0 copied 328 @ from the exception stack 329 330 @ 331 @ We are now ready to fill in the remaining blanks on the stack: 332 @ 333 @ r4 - lr_<exception>, already fixed up for correct return/restart 334 @ r5 - spsr_<exception> 335 @ r6 - orig_r0 (see pt_regs definition in ptrace.h) 336 @ 337 @ Also, separately save sp_usr and lr_usr 338 @ 339 stmia r0, {r4 - r6} 340 ARM( stmdb r0, {sp, lr}^ ) 341 THUMB( store_user_sp_lr r0, r1, S_SP - S_PC ) 342 343 @ 344 @ Enable the alignment trap while in kernel mode 345 @ 346 alignment_trap r0 347 348 @ 349 @ Clear FP to mark the first stack frame 350 @ 351 zero_fp 352 353#ifdef CONFIG_IRQSOFF_TRACER 354 bl trace_hardirqs_off 355#endif 356 ct_user_exit save = 0 357 .endm 358 359 .macro kuser_cmpxchg_check 360#if !defined(CONFIG_CPU_32v6K) && !defined(CONFIG_NEEDS_SYSCALL_FOR_CMPXCHG) 361#ifndef CONFIG_MMU 362#warning "NPTL on non MMU needs fixing" 363#else 364 @ Make sure our user space atomic helper is restarted 365 @ if it was interrupted in a critical region. Here we 366 @ perform a quick test inline since it should be false 367 @ 99.9999% of the time. The rest is done out of line. 368 cmp r4, #TASK_SIZE 369 blhs kuser_cmpxchg64_fixup 370#endif 371#endif 372 .endm 373 374 .align 5 375__dabt_usr: 376 usr_entry 377 kuser_cmpxchg_check 378 mov r2, sp 379 dabt_helper 380 b ret_from_exception 381 UNWIND(.fnend ) 382ENDPROC(__dabt_usr) 383 384 .align 5 385__irq_usr: 386 usr_entry 387 kuser_cmpxchg_check 388 irq_handler 389 get_thread_info tsk 390 mov why, #0 391 b ret_to_user_from_irq 392 UNWIND(.fnend ) 393ENDPROC(__irq_usr) 394 395 .ltorg 396 397 .align 5 398__und_usr: 399 usr_entry 400 401 mov r2, r4 402 mov r3, r5 403 404 @ r2 = regs->ARM_pc, which is either 2 or 4 bytes ahead of the 405 @ faulting instruction depending on Thumb mode. 406 @ r3 = regs->ARM_cpsr 407 @ 408 @ The emulation code returns using r9 if it has emulated the 409 @ instruction, or the more conventional lr if we are to treat 410 @ this as a real undefined instruction 411 @ 412 adr r9, BSYM(ret_from_exception) 413 414 tst r3, #PSR_T_BIT @ Thumb mode? 415 bne __und_usr_thumb 416 sub r4, r2, #4 @ ARM instr at LR - 4 4171: ldrt r0, [r4] 418#ifdef CONFIG_CPU_ENDIAN_BE8 419 rev r0, r0 @ little endian instruction 420#endif 421 @ r0 = 32-bit ARM instruction which caused the exception 422 @ r2 = PC value for the following instruction (:= regs->ARM_pc) 423 @ r4 = PC value for the faulting instruction 424 @ lr = 32-bit undefined instruction function 425 adr lr, BSYM(__und_usr_fault_32) 426 b call_fpe 427 428__und_usr_thumb: 429 @ Thumb instruction 430 sub r4, r2, #2 @ First half of thumb instr at LR - 2 431#if CONFIG_ARM_THUMB && __LINUX_ARM_ARCH__ >= 6 && CONFIG_CPU_V7 432/* 433 * Thumb-2 instruction handling. Note that because pre-v6 and >= v6 platforms 434 * can never be supported in a single kernel, this code is not applicable at 435 * all when __LINUX_ARM_ARCH__ < 6. This allows simplifying assumptions to be 436 * made about .arch directives. 437 */ 438#if __LINUX_ARM_ARCH__ < 7 439/* If the target CPU may not be Thumb-2-capable, a run-time check is needed: */ 440#define NEED_CPU_ARCHITECTURE 441 ldr r5, .LCcpu_architecture 442 ldr r5, [r5] 443 cmp r5, #CPU_ARCH_ARMv7 444 blo __und_usr_fault_16 @ 16bit undefined instruction 445/* 446 * The following code won't get run unless the running CPU really is v7, so 447 * coding round the lack of ldrht on older arches is pointless. Temporarily 448 * override the assembler target arch with the minimum required instead: 449 */ 450 .arch armv6t2 451#endif 4522: ldrht r5, [r4] 453 cmp r5, #0xe800 @ 32bit instruction if xx != 0 454 blo __und_usr_fault_16 @ 16bit undefined instruction 4553: ldrht r0, [r2] 456 add r2, r2, #2 @ r2 is PC + 2, make it PC + 4 457 str r2, [sp, #S_PC] @ it's a 2x16bit instr, update 458 orr r0, r0, r5, lsl #16 459 adr lr, BSYM(__und_usr_fault_32) 460 @ r0 = the two 16-bit Thumb instructions which caused the exception 461 @ r2 = PC value for the following Thumb instruction (:= regs->ARM_pc) 462 @ r4 = PC value for the first 16-bit Thumb instruction 463 @ lr = 32bit undefined instruction function 464 465#if __LINUX_ARM_ARCH__ < 7 466/* If the target arch was overridden, change it back: */ 467#ifdef CONFIG_CPU_32v6K 468 .arch armv6k 469#else 470 .arch armv6 471#endif 472#endif /* __LINUX_ARM_ARCH__ < 7 */ 473#else /* !(CONFIG_ARM_THUMB && __LINUX_ARM_ARCH__ >= 6 && CONFIG_CPU_V7) */ 474 b __und_usr_fault_16 475#endif 476 UNWIND(.fnend) 477ENDPROC(__und_usr) 478 479/* 480 * The out of line fixup for the ldrt instructions above. 481 */ 482 .pushsection .fixup, "ax" 483 .align 2 4844: mov pc, r9 485 .popsection 486 .pushsection __ex_table,"a" 487 .long 1b, 4b 488#if CONFIG_ARM_THUMB && __LINUX_ARM_ARCH__ >= 6 && CONFIG_CPU_V7 489 .long 2b, 4b 490 .long 3b, 4b 491#endif 492 .popsection 493 494/* 495 * Check whether the instruction is a co-processor instruction. 496 * If yes, we need to call the relevant co-processor handler. 497 * 498 * Note that we don't do a full check here for the co-processor 499 * instructions; all instructions with bit 27 set are well 500 * defined. The only instructions that should fault are the 501 * co-processor instructions. However, we have to watch out 502 * for the ARM6/ARM7 SWI bug. 503 * 504 * NEON is a special case that has to be handled here. Not all 505 * NEON instructions are co-processor instructions, so we have 506 * to make a special case of checking for them. Plus, there's 507 * five groups of them, so we have a table of mask/opcode pairs 508 * to check against, and if any match then we branch off into the 509 * NEON handler code. 510 * 511 * Emulators may wish to make use of the following registers: 512 * r0 = instruction opcode (32-bit ARM or two 16-bit Thumb) 513 * r2 = PC value to resume execution after successful emulation 514 * r9 = normal "successful" return address 515 * r10 = this threads thread_info structure 516 * lr = unrecognised instruction return address 517 * IRQs disabled, FIQs enabled. 518 */ 519 @ 520 @ Fall-through from Thumb-2 __und_usr 521 @ 522#ifdef CONFIG_NEON 523 get_thread_info r10 @ get current thread 524 adr r6, .LCneon_thumb_opcodes 525 b 2f 526#endif 527call_fpe: 528 get_thread_info r10 @ get current thread 529#ifdef CONFIG_NEON 530 adr r6, .LCneon_arm_opcodes 5312: ldr r5, [r6], #4 @ mask value 532 ldr r7, [r6], #4 @ opcode bits matching in mask 533 cmp r5, #0 @ end mask? 534 beq 1f 535 and r8, r0, r5 536 cmp r8, r7 @ NEON instruction? 537 bne 2b 538 mov r7, #1 539 strb r7, [r10, #TI_USED_CP + 10] @ mark CP#10 as used 540 strb r7, [r10, #TI_USED_CP + 11] @ mark CP#11 as used 541 b do_vfp @ let VFP handler handle this 5421: 543#endif 544 tst r0, #0x08000000 @ only CDP/CPRT/LDC/STC have bit 27 545 tstne r0, #0x04000000 @ bit 26 set on both ARM and Thumb-2 546 moveq pc, lr 547 and r8, r0, #0x00000f00 @ mask out CP number 548 THUMB( lsr r8, r8, #8 ) 549 mov r7, #1 550 add r6, r10, #TI_USED_CP 551 ARM( strb r7, [r6, r8, lsr #8] ) @ set appropriate used_cp[] 552 THUMB( strb r7, [r6, r8] ) @ set appropriate used_cp[] 553#ifdef CONFIG_IWMMXT 554 @ Test if we need to give access to iWMMXt coprocessors 555 ldr r5, [r10, #TI_FLAGS] 556 rsbs r7, r8, #(1 << 8) @ CP 0 or 1 only 557 movcss r7, r5, lsr #(TIF_USING_IWMMXT + 1) 558 bcs iwmmxt_task_enable 559#endif 560 ARM( add pc, pc, r8, lsr #6 ) 561 THUMB( lsl r8, r8, #2 ) 562 THUMB( add pc, r8 ) 563 nop 564 565 movw_pc lr @ CP#0 566 W(b) do_fpe @ CP#1 (FPE) 567 W(b) do_fpe @ CP#2 (FPE) 568 movw_pc lr @ CP#3 569#ifdef CONFIG_CRUNCH 570 b crunch_task_enable @ CP#4 (MaverickCrunch) 571 b crunch_task_enable @ CP#5 (MaverickCrunch) 572 b crunch_task_enable @ CP#6 (MaverickCrunch) 573#else 574 movw_pc lr @ CP#4 575 movw_pc lr @ CP#5 576 movw_pc lr @ CP#6 577#endif 578 movw_pc lr @ CP#7 579 movw_pc lr @ CP#8 580 movw_pc lr @ CP#9 581#ifdef CONFIG_VFP 582 W(b) do_vfp @ CP#10 (VFP) 583 W(b) do_vfp @ CP#11 (VFP) 584#else 585 movw_pc lr @ CP#10 (VFP) 586 movw_pc lr @ CP#11 (VFP) 587#endif 588 movw_pc lr @ CP#12 589 movw_pc lr @ CP#13 590 movw_pc lr @ CP#14 (Debug) 591 movw_pc lr @ CP#15 (Control) 592 593#ifdef NEED_CPU_ARCHITECTURE 594 .align 2 595.LCcpu_architecture: 596 .word __cpu_architecture 597#endif 598 599#ifdef CONFIG_NEON 600 .align 6 601 602.LCneon_arm_opcodes: 603 .word 0xfe000000 @ mask 604 .word 0xf2000000 @ opcode 605 606 .word 0xff100000 @ mask 607 .word 0xf4000000 @ opcode 608 609 .word 0x00000000 @ mask 610 .word 0x00000000 @ opcode 611 612.LCneon_thumb_opcodes: 613 .word 0xef000000 @ mask 614 .word 0xef000000 @ opcode 615 616 .word 0xff100000 @ mask 617 .word 0xf9000000 @ opcode 618 619 .word 0x00000000 @ mask 620 .word 0x00000000 @ opcode 621#endif 622 623do_fpe: 624 enable_irq 625 ldr r4, .LCfp 626 add r10, r10, #TI_FPSTATE @ r10 = workspace 627 ldr pc, [r4] @ Call FP module USR entry point 628 629/* 630 * The FP module is called with these registers set: 631 * r0 = instruction 632 * r2 = PC+4 633 * r9 = normal "successful" return address 634 * r10 = FP workspace 635 * lr = unrecognised FP instruction return address 636 */ 637 638 .pushsection .data 639ENTRY(fp_enter) 640 .word no_fp 641 .popsection 642 643ENTRY(no_fp) 644 mov pc, lr 645ENDPROC(no_fp) 646 647__und_usr_fault_32: 648 mov r1, #4 649 b 1f 650__und_usr_fault_16: 651 mov r1, #2 6521: enable_irq 653 mov r0, sp 654 adr lr, BSYM(ret_from_exception) 655 b __und_fault 656ENDPROC(__und_usr_fault_32) 657ENDPROC(__und_usr_fault_16) 658 659 .align 5 660__pabt_usr: 661 usr_entry 662 mov r2, sp @ regs 663 pabt_helper 664 UNWIND(.fnend ) 665 /* fall through */ 666/* 667 * This is the return code to user mode for abort handlers 668 */ 669ENTRY(ret_from_exception) 670 UNWIND(.fnstart ) 671 UNWIND(.cantunwind ) 672 get_thread_info tsk 673 mov why, #0 674 b ret_to_user 675 UNWIND(.fnend ) 676ENDPROC(__pabt_usr) 677ENDPROC(ret_from_exception) 678 679/* 680 * Register switch for ARMv3 and ARMv4 processors 681 * r0 = previous task_struct, r1 = previous thread_info, r2 = next thread_info 682 * previous and next are guaranteed not to be the same. 683 */ 684ENTRY(__switch_to) 685 UNWIND(.fnstart ) 686 UNWIND(.cantunwind ) 687 add ip, r1, #TI_CPU_SAVE 688 ARM( stmia ip!, {r4 - sl, fp, sp, lr} ) @ Store most regs on stack 689 THUMB( stmia ip!, {r4 - sl, fp} ) @ Store most regs on stack 690 THUMB( str sp, [ip], #4 ) 691 THUMB( str lr, [ip], #4 ) 692 ldr r4, [r2, #TI_TP_VALUE] 693 ldr r5, [r2, #TI_TP_VALUE + 4] 694#ifdef CONFIG_CPU_USE_DOMAINS 695 ldr r6, [r2, #TI_CPU_DOMAIN] 696#endif 697 switch_tls r1, r4, r5, r3, r7 698#if defined(CONFIG_CC_STACKPROTECTOR) && !defined(CONFIG_SMP) 699 ldr r7, [r2, #TI_TASK] 700 ldr r8, =__stack_chk_guard 701 ldr r7, [r7, #TSK_STACK_CANARY] 702#endif 703#ifdef CONFIG_CPU_USE_DOMAINS 704 mcr p15, 0, r6, c3, c0, 0 @ Set domain register 705#endif 706 mov r5, r0 707 add r4, r2, #TI_CPU_SAVE 708 ldr r0, =thread_notify_head 709 mov r1, #THREAD_NOTIFY_SWITCH 710 bl atomic_notifier_call_chain 711#if defined(CONFIG_CC_STACKPROTECTOR) && !defined(CONFIG_SMP) 712 str r7, [r8] 713#endif 714 THUMB( mov ip, r4 ) 715 mov r0, r5 716 ARM( ldmia r4, {r4 - sl, fp, sp, pc} ) @ Load all regs saved previously 717 THUMB( ldmia ip!, {r4 - sl, fp} ) @ Load all regs saved previously 718 THUMB( ldr sp, [ip], #4 ) 719 THUMB( ldr pc, [ip] ) 720 UNWIND(.fnend ) 721ENDPROC(__switch_to) 722 723 __INIT 724 725/* 726 * User helpers. 727 * 728 * Each segment is 32-byte aligned and will be moved to the top of the high 729 * vector page. New segments (if ever needed) must be added in front of 730 * existing ones. This mechanism should be used only for things that are 731 * really small and justified, and not be abused freely. 732 * 733 * See Documentation/arm/kernel_user_helpers.txt for formal definitions. 734 */ 735 THUMB( .arm ) 736 737 .macro usr_ret, reg 738#ifdef CONFIG_ARM_THUMB 739 bx \reg 740#else 741 mov pc, \reg 742#endif 743 .endm 744 745 .align 5 746 .globl __kuser_helper_start 747__kuser_helper_start: 748 749/* 750 * Due to the length of some sequences, __kuser_cmpxchg64 spans 2 regular 751 * kuser "slots", therefore 0xffff0f80 is not used as a valid entry point. 752 */ 753 754__kuser_cmpxchg64: @ 0xffff0f60 755 756#if defined(CONFIG_NEEDS_SYSCALL_FOR_CMPXCHG) 757 758 /* 759 * Poor you. No fast solution possible... 760 * The kernel itself must perform the operation. 761 * A special ghost syscall is used for that (see traps.c). 762 */ 763 stmfd sp!, {r7, lr} 764 ldr r7, 1f @ it's 20 bits 765 swi __ARM_NR_cmpxchg64 766 ldmfd sp!, {r7, pc} 7671: .word __ARM_NR_cmpxchg64 768 769#elif defined(CONFIG_CPU_32v6K) 770 771 stmfd sp!, {r4, r5, r6, r7} 772 ldrd r4, r5, [r0] @ load old val 773 ldrd r6, r7, [r1] @ load new val 774 smp_dmb arm 7751: ldrexd r0, r1, [r2] @ load current val 776 eors r3, r0, r4 @ compare with oldval (1) 777 eoreqs r3, r1, r5 @ compare with oldval (2) 778 strexdeq r3, r6, r7, [r2] @ store newval if eq 779 teqeq r3, #1 @ success? 780 beq 1b @ if no then retry 781 smp_dmb arm 782 rsbs r0, r3, #0 @ set returned val and C flag 783 ldmfd sp!, {r4, r5, r6, r7} 784 usr_ret lr 785 786#elif !defined(CONFIG_SMP) 787 788#ifdef CONFIG_MMU 789 790 /* 791 * The only thing that can break atomicity in this cmpxchg64 792 * implementation is either an IRQ or a data abort exception 793 * causing another process/thread to be scheduled in the middle of 794 * the critical sequence. The same strategy as for cmpxchg is used. 795 */ 796 stmfd sp!, {r4, r5, r6, lr} 797 ldmia r0, {r4, r5} @ load old val 798 ldmia r1, {r6, lr} @ load new val 7991: ldmia r2, {r0, r1} @ load current val 800 eors r3, r0, r4 @ compare with oldval (1) 801 eoreqs r3, r1, r5 @ compare with oldval (2) 8022: stmeqia r2, {r6, lr} @ store newval if eq 803 rsbs r0, r3, #0 @ set return val and C flag 804 ldmfd sp!, {r4, r5, r6, pc} 805 806 .text 807kuser_cmpxchg64_fixup: 808 @ Called from kuser_cmpxchg_fixup. 809 @ r4 = address of interrupted insn (must be preserved). 810 @ sp = saved regs. r7 and r8 are clobbered. 811 @ 1b = first critical insn, 2b = last critical insn. 812 @ If r4 >= 1b and r4 <= 2b then saved pc_usr is set to 1b. 813 mov r7, #0xffff0fff 814 sub r7, r7, #(0xffff0fff - (0xffff0f60 + (1b - __kuser_cmpxchg64))) 815 subs r8, r4, r7 816 rsbcss r8, r8, #(2b - 1b) 817 strcs r7, [sp, #S_PC] 818#if __LINUX_ARM_ARCH__ < 6 819 bcc kuser_cmpxchg32_fixup 820#endif 821 mov pc, lr 822 .previous 823 824#else 825#warning "NPTL on non MMU needs fixing" 826 mov r0, #-1 827 adds r0, r0, #0 828 usr_ret lr 829#endif 830 831#else 832#error "incoherent kernel configuration" 833#endif 834 835 /* pad to next slot */ 836 .rept (16 - (. - __kuser_cmpxchg64)/4) 837 .word 0 838 .endr 839 840 .align 5 841 842__kuser_memory_barrier: @ 0xffff0fa0 843 smp_dmb arm 844 usr_ret lr 845 846 .align 5 847 848__kuser_cmpxchg: @ 0xffff0fc0 849 850#if defined(CONFIG_NEEDS_SYSCALL_FOR_CMPXCHG) 851 852 /* 853 * Poor you. No fast solution possible... 854 * The kernel itself must perform the operation. 855 * A special ghost syscall is used for that (see traps.c). 856 */ 857 stmfd sp!, {r7, lr} 858 ldr r7, 1f @ it's 20 bits 859 swi __ARM_NR_cmpxchg 860 ldmfd sp!, {r7, pc} 8611: .word __ARM_NR_cmpxchg 862 863#elif __LINUX_ARM_ARCH__ < 6 864 865#ifdef CONFIG_MMU 866 867 /* 868 * The only thing that can break atomicity in this cmpxchg 869 * implementation is either an IRQ or a data abort exception 870 * causing another process/thread to be scheduled in the middle 871 * of the critical sequence. To prevent this, code is added to 872 * the IRQ and data abort exception handlers to set the pc back 873 * to the beginning of the critical section if it is found to be 874 * within that critical section (see kuser_cmpxchg_fixup). 875 */ 8761: ldr r3, [r2] @ load current val 877 subs r3, r3, r0 @ compare with oldval 8782: streq r1, [r2] @ store newval if eq 879 rsbs r0, r3, #0 @ set return val and C flag 880 usr_ret lr 881 882 .text 883kuser_cmpxchg32_fixup: 884 @ Called from kuser_cmpxchg_check macro. 885 @ r4 = address of interrupted insn (must be preserved). 886 @ sp = saved regs. r7 and r8 are clobbered. 887 @ 1b = first critical insn, 2b = last critical insn. 888 @ If r4 >= 1b and r4 <= 2b then saved pc_usr is set to 1b. 889 mov r7, #0xffff0fff 890 sub r7, r7, #(0xffff0fff - (0xffff0fc0 + (1b - __kuser_cmpxchg))) 891 subs r8, r4, r7 892 rsbcss r8, r8, #(2b - 1b) 893 strcs r7, [sp, #S_PC] 894 mov pc, lr 895 .previous 896 897#else 898#warning "NPTL on non MMU needs fixing" 899 mov r0, #-1 900 adds r0, r0, #0 901 usr_ret lr 902#endif 903 904#else 905 906 smp_dmb arm 9071: ldrex r3, [r2] 908 subs r3, r3, r0 909 strexeq r3, r1, [r2] 910 teqeq r3, #1 911 beq 1b 912 rsbs r0, r3, #0 913 /* beware -- each __kuser slot must be 8 instructions max */ 914 ALT_SMP(b __kuser_memory_barrier) 915 ALT_UP(usr_ret lr) 916 917#endif 918 919 .align 5 920 921__kuser_get_tls: @ 0xffff0fe0 922 ldr r0, [pc, #(16 - 8)] @ read TLS, set in kuser_get_tls_init 923 usr_ret lr 924 mrc p15, 0, r0, c13, c0, 3 @ 0xffff0fe8 hardware TLS code 925 .rep 4 926 .word 0 @ 0xffff0ff0 software TLS value, then 927 .endr @ pad up to __kuser_helper_version 928 929__kuser_helper_version: @ 0xffff0ffc 930 .word ((__kuser_helper_end - __kuser_helper_start) >> 5) 931 932 .globl __kuser_helper_end 933__kuser_helper_end: 934 935 THUMB( .thumb ) 936 937/* 938 * Vector stubs. 939 * 940 * This code is copied to 0xffff0200 so we can use branches in the 941 * vectors, rather than ldr's. Note that this code must not 942 * exceed 0x300 bytes. 943 * 944 * Common stub entry macro: 945 * Enter in IRQ mode, spsr = SVC/USR CPSR, lr = SVC/USR PC 946 * 947 * SP points to a minimal amount of processor-private memory, the address 948 * of which is copied into r0 for the mode specific abort handler. 949 */ 950 .macro vector_stub, name, mode, correction=0 951 .align 5 952 953vector_\name: 954 .if \correction 955 sub lr, lr, #\correction 956 .endif 957 958 @ 959 @ Save r0, lr_<exception> (parent PC) and spsr_<exception> 960 @ (parent CPSR) 961 @ 962 stmia sp, {r0, lr} @ save r0, lr 963 mrs lr, spsr 964 str lr, [sp, #8] @ save spsr 965 966 @ 967 @ Prepare for SVC32 mode. IRQs remain disabled. 968 @ 969 mrs r0, cpsr 970 eor r0, r0, #(\mode ^ SVC_MODE | PSR_ISETSTATE) 971 msr spsr_cxsf, r0 972 973 @ 974 @ the branch table must immediately follow this code 975 @ 976 and lr, lr, #0x0f 977 THUMB( adr r0, 1f ) 978 THUMB( ldr lr, [r0, lr, lsl #2] ) 979 mov r0, sp 980 ARM( ldr lr, [pc, lr, lsl #2] ) 981 movs pc, lr @ branch to handler in SVC mode 982ENDPROC(vector_\name) 983 984 .align 2 985 @ handler addresses follow this label 9861: 987 .endm 988 989 .globl __stubs_start 990__stubs_start: 991/* 992 * Interrupt dispatcher 993 */ 994 vector_stub irq, IRQ_MODE, 4 995 996 .long __irq_usr @ 0 (USR_26 / USR_32) 997 .long __irq_invalid @ 1 (FIQ_26 / FIQ_32) 998 .long __irq_invalid @ 2 (IRQ_26 / IRQ_32) 999 .long __irq_svc @ 3 (SVC_26 / SVC_32) 1000 .long __irq_invalid @ 4 1001 .long __irq_invalid @ 5 1002 .long __irq_invalid @ 6 1003 .long __irq_invalid @ 7 1004 .long __irq_invalid @ 8 1005 .long __irq_invalid @ 9 1006 .long __irq_invalid @ a 1007 .long __irq_invalid @ b 1008 .long __irq_invalid @ c 1009 .long __irq_invalid @ d 1010 .long __irq_invalid @ e 1011 .long __irq_invalid @ f 1012 1013/* 1014 * Data abort dispatcher 1015 * Enter in ABT mode, spsr = USR CPSR, lr = USR PC 1016 */ 1017 vector_stub dabt, ABT_MODE, 8 1018 1019 .long __dabt_usr @ 0 (USR_26 / USR_32) 1020 .long __dabt_invalid @ 1 (FIQ_26 / FIQ_32) 1021 .long __dabt_invalid @ 2 (IRQ_26 / IRQ_32) 1022 .long __dabt_svc @ 3 (SVC_26 / SVC_32) 1023 .long __dabt_invalid @ 4 1024 .long __dabt_invalid @ 5 1025 .long __dabt_invalid @ 6 1026 .long __dabt_invalid @ 7 1027 .long __dabt_invalid @ 8 1028 .long __dabt_invalid @ 9 1029 .long __dabt_invalid @ a 1030 .long __dabt_invalid @ b 1031 .long __dabt_invalid @ c 1032 .long __dabt_invalid @ d 1033 .long __dabt_invalid @ e 1034 .long __dabt_invalid @ f 1035 1036/* 1037 * Prefetch abort dispatcher 1038 * Enter in ABT mode, spsr = USR CPSR, lr = USR PC 1039 */ 1040 vector_stub pabt, ABT_MODE, 4 1041 1042 .long __pabt_usr @ 0 (USR_26 / USR_32) 1043 .long __pabt_invalid @ 1 (FIQ_26 / FIQ_32) 1044 .long __pabt_invalid @ 2 (IRQ_26 / IRQ_32) 1045 .long __pabt_svc @ 3 (SVC_26 / SVC_32) 1046 .long __pabt_invalid @ 4 1047 .long __pabt_invalid @ 5 1048 .long __pabt_invalid @ 6 1049 .long __pabt_invalid @ 7 1050 .long __pabt_invalid @ 8 1051 .long __pabt_invalid @ 9 1052 .long __pabt_invalid @ a 1053 .long __pabt_invalid @ b 1054 .long __pabt_invalid @ c 1055 .long __pabt_invalid @ d 1056 .long __pabt_invalid @ e 1057 .long __pabt_invalid @ f 1058 1059/* 1060 * Undef instr entry dispatcher 1061 * Enter in UND mode, spsr = SVC/USR CPSR, lr = SVC/USR PC 1062 */ 1063 vector_stub und, UND_MODE 1064 1065 .long __und_usr @ 0 (USR_26 / USR_32) 1066 .long __und_invalid @ 1 (FIQ_26 / FIQ_32) 1067 .long __und_invalid @ 2 (IRQ_26 / IRQ_32) 1068 .long __und_svc @ 3 (SVC_26 / SVC_32) 1069 .long __und_invalid @ 4 1070 .long __und_invalid @ 5 1071 .long __und_invalid @ 6 1072 .long __und_invalid @ 7 1073 .long __und_invalid @ 8 1074 .long __und_invalid @ 9 1075 .long __und_invalid @ a 1076 .long __und_invalid @ b 1077 .long __und_invalid @ c 1078 .long __und_invalid @ d 1079 .long __und_invalid @ e 1080 .long __und_invalid @ f 1081 1082 .align 5 1083 1084/*============================================================================= 1085 * Undefined FIQs 1086 *----------------------------------------------------------------------------- 1087 * Enter in FIQ mode, spsr = ANY CPSR, lr = ANY PC 1088 * MUST PRESERVE SVC SPSR, but need to switch to SVC mode to show our msg. 1089 * Basically to switch modes, we *HAVE* to clobber one register... brain 1090 * damage alert! I don't think that we can execute any code in here in any 1091 * other mode than FIQ... Ok you can switch to another mode, but you can't 1092 * get out of that mode without clobbering one register. 1093 */ 1094vector_fiq: 1095 subs pc, lr, #4 1096 1097/*============================================================================= 1098 * Address exception handler 1099 *----------------------------------------------------------------------------- 1100 * These aren't too critical. 1101 * (they're not supposed to happen, and won't happen in 32-bit data mode). 1102 */ 1103 1104vector_addrexcptn: 1105 b vector_addrexcptn 1106 1107/* 1108 * We group all the following data together to optimise 1109 * for CPUs with separate I & D caches. 1110 */ 1111 .align 5 1112 1113.LCvswi: 1114 .word vector_swi 1115 1116 .globl __stubs_end 1117__stubs_end: 1118 1119 .equ stubs_offset, __vectors_start + 0x200 - __stubs_start 1120 1121 .globl __vectors_start 1122__vectors_start: 1123 ARM( swi SYS_ERROR0 ) 1124 THUMB( svc #0 ) 1125 THUMB( nop ) 1126 W(b) vector_und + stubs_offset 1127 W(ldr) pc, .LCvswi + stubs_offset 1128 W(b) vector_pabt + stubs_offset 1129 W(b) vector_dabt + stubs_offset 1130 W(b) vector_addrexcptn + stubs_offset 1131 W(b) vector_irq + stubs_offset 1132 W(b) vector_fiq + stubs_offset 1133 1134 .globl __vectors_end 1135__vectors_end: 1136 1137 .data 1138 1139 .globl cr_alignment 1140 .globl cr_no_alignment 1141cr_alignment: 1142 .space 4 1143cr_no_alignment: 1144 .space 4 1145 1146#ifdef CONFIG_MULTI_IRQ_HANDLER 1147 .globl handle_arch_irq 1148handle_arch_irq: 1149 .space 4 1150#endif 1151