1/* SPDX-License-Identifier: GPL-2.0-only */ 2/* 3 * linux/arch/arm/kernel/entry-armv.S 4 * 5 * Copyright (C) 1996,1997,1998 Russell King. 6 * ARM700 fix by Matthew Godbolt (linux-user@willothewisp.demon.co.uk) 7 * nommu support by Hyok S. Choi (hyok.choi@samsung.com) 8 * 9 * Low-level vector interface routines 10 * 11 * Note: there is a StrongARM bug in the STMIA rn, {regs}^ instruction 12 * that causes it to save wrong values... Be aware! 13 */ 14 15#include <linux/init.h> 16 17#include <asm/assembler.h> 18#include <asm/page.h> 19#include <asm/glue-df.h> 20#include <asm/glue-pf.h> 21#include <asm/vfpmacros.h> 22#include <asm/thread_notify.h> 23#include <asm/unwind.h> 24#include <asm/unistd.h> 25#include <asm/tls.h> 26#include <asm/system_info.h> 27#include <asm/uaccess-asm.h> 28 29#include "entry-header.S" 30#include <asm/probes.h> 31 32/* 33 * Interrupt handling. 34 */ 35 .macro irq_handler, from_user:req 36 mov r1, sp 37 ldr_this_cpu r2, irq_stack_ptr, r2, r3 38 .if \from_user == 0 39 @ 40 @ If we took the interrupt while running in the kernel, we may already 41 @ be using the IRQ stack, so revert to the original value in that case. 42 @ 43 subs r3, r2, r1 @ SP above bottom of IRQ stack? 44 rsbscs r3, r3, #THREAD_SIZE @ ... and below the top? 45#ifdef CONFIG_VMAP_STACK 46 ldr_va r3, high_memory, cc @ End of the linear region 47 cmpcc r3, r1 @ Stack pointer was below it? 48#endif 49 bcc 0f @ If not, switch to the IRQ stack 50 mov r0, r1 51 bl generic_handle_arch_irq 52 b 1f 530: 54 .endif 55 56 mov_l r0, generic_handle_arch_irq 57 bl call_with_stack 581: 59 .endm 60 61 .macro pabt_helper 62 @ PABORT handler takes pt_regs in r2, fault address in r4 and psr in r5 63#ifdef MULTI_PABORT 64 ldr_va ip, processor, offset=PROCESSOR_PABT_FUNC 65 bl_r ip 66#else 67 bl CPU_PABORT_HANDLER 68#endif 69 .endm 70 71 .macro dabt_helper 72 73 @ 74 @ Call the processor-specific abort handler: 75 @ 76 @ r2 - pt_regs 77 @ r4 - aborted context pc 78 @ r5 - aborted context psr 79 @ 80 @ The abort handler must return the aborted address in r0, and 81 @ the fault status register in r1. r9 must be preserved. 82 @ 83#ifdef MULTI_DABORT 84 ldr_va ip, processor, offset=PROCESSOR_DABT_FUNC 85 bl_r ip 86#else 87 bl CPU_DABORT_HANDLER 88#endif 89 .endm 90 91 .section .entry.text,"ax",%progbits 92 93/* 94 * Invalid mode handlers 95 */ 96 .macro inv_entry, reason 97 sub sp, sp, #PT_REGS_SIZE 98 ARM( stmib sp, {r1 - lr} ) 99 THUMB( stmia sp, {r0 - r12} ) 100 THUMB( str sp, [sp, #S_SP] ) 101 THUMB( str lr, [sp, #S_LR] ) 102 mov r1, #\reason 103 .endm 104 105__pabt_invalid: 106 inv_entry BAD_PREFETCH 107 b common_invalid 108ENDPROC(__pabt_invalid) 109 110__dabt_invalid: 111 inv_entry BAD_DATA 112 b common_invalid 113ENDPROC(__dabt_invalid) 114 115__irq_invalid: 116 inv_entry BAD_IRQ 117 b common_invalid 118ENDPROC(__irq_invalid) 119 120__und_invalid: 121 inv_entry BAD_UNDEFINSTR 122 123 @ 124 @ XXX fall through to common_invalid 125 @ 126 127@ 128@ common_invalid - generic code for failed exception (re-entrant version of handlers) 129@ 130common_invalid: 131 zero_fp 132 133 ldmia r0, {r4 - r6} 134 add r0, sp, #S_PC @ here for interlock avoidance 135 mov r7, #-1 @ "" "" "" "" 136 str r4, [sp] @ save preserved r0 137 stmia r0, {r5 - r7} @ lr_<exception>, 138 @ cpsr_<exception>, "old_r0" 139 140 mov r0, sp 141 b bad_mode 142ENDPROC(__und_invalid) 143 144/* 145 * SVC mode handlers 146 */ 147 148#if defined(CONFIG_AEABI) && (__LINUX_ARM_ARCH__ >= 5) 149#define SPFIX(code...) code 150#else 151#define SPFIX(code...) 152#endif 153 154 .macro svc_entry, stack_hole=0, trace=1, uaccess=1, overflow_check=1 155 UNWIND(.fnstart ) 156 sub sp, sp, #(SVC_REGS_SIZE + \stack_hole) 157 THUMB( add sp, r1 ) @ get SP in a GPR without 158 THUMB( sub r1, sp, r1 ) @ using a temp register 159 160 .if \overflow_check 161 UNWIND(.save {r0 - pc} ) 162 do_overflow_check (SVC_REGS_SIZE + \stack_hole) 163 .endif 164 165#ifdef CONFIG_THUMB2_KERNEL 166 tst r1, #4 @ test stack pointer alignment 167 sub r1, sp, r1 @ restore original R1 168 sub sp, r1 @ restore original SP 169#else 170 SPFIX( tst sp, #4 ) 171#endif 172 SPFIX( subne sp, sp, #4 ) 173 174 ARM( stmib sp, {r1 - r12} ) 175 THUMB( stmia sp, {r0 - r12} ) @ No STMIB in Thumb-2 176 177 ldmia r0, {r3 - r5} 178 add r7, sp, #S_SP @ here for interlock avoidance 179 mov r6, #-1 @ "" "" "" "" 180 add r2, sp, #(SVC_REGS_SIZE + \stack_hole) 181 SPFIX( addne r2, r2, #4 ) 182 str r3, [sp] @ save the "real" r0 copied 183 @ from the exception stack 184 185 mov r3, lr 186 187 @ 188 @ We are now ready to fill in the remaining blanks on the stack: 189 @ 190 @ r2 - sp_svc 191 @ r3 - lr_svc 192 @ r4 - lr_<exception>, already fixed up for correct return/restart 193 @ r5 - spsr_<exception> 194 @ r6 - orig_r0 (see pt_regs definition in ptrace.h) 195 @ 196 stmia r7, {r2 - r6} 197 198 get_thread_info tsk 199 uaccess_entry tsk, r0, r1, r2, \uaccess 200 201 .if \trace 202#ifdef CONFIG_TRACE_IRQFLAGS 203 bl trace_hardirqs_off 204#endif 205 .endif 206 .endm 207 208 .align 5 209__dabt_svc: 210 svc_entry uaccess=0 211 mov r2, sp 212 dabt_helper 213 THUMB( ldr r5, [sp, #S_PSR] ) @ potentially updated CPSR 214 svc_exit r5 @ return from exception 215 UNWIND(.fnend ) 216ENDPROC(__dabt_svc) 217 218 .align 5 219__irq_svc: 220 svc_entry 221 irq_handler from_user=0 222 223#ifdef CONFIG_PREEMPTION 224 ldr r8, [tsk, #TI_PREEMPT] @ get preempt count 225 ldr r0, [tsk, #TI_FLAGS] @ get flags 226 teq r8, #0 @ if preempt count != 0 227 movne r0, #0 @ force flags to 0 228 tst r0, #_TIF_NEED_RESCHED 229 blne svc_preempt 230#endif 231 232 svc_exit r5, irq = 1 @ return from exception 233 UNWIND(.fnend ) 234ENDPROC(__irq_svc) 235 236 .ltorg 237 238#ifdef CONFIG_PREEMPTION 239svc_preempt: 240 mov r8, lr 2411: bl preempt_schedule_irq @ irq en/disable is done inside 242 ldr r0, [tsk, #TI_FLAGS] @ get new tasks TI_FLAGS 243 tst r0, #_TIF_NEED_RESCHED 244 reteq r8 @ go again 245 b 1b 246#endif 247 248__und_fault: 249 @ Correct the PC such that it is pointing at the instruction 250 @ which caused the fault. If the faulting instruction was ARM 251 @ the PC will be pointing at the next instruction, and have to 252 @ subtract 4. Otherwise, it is Thumb, and the PC will be 253 @ pointing at the second half of the Thumb instruction. We 254 @ have to subtract 2. 255 ldr r2, [r0, #S_PC] 256 sub r2, r2, r1 257 str r2, [r0, #S_PC] 258 b do_undefinstr 259ENDPROC(__und_fault) 260 261 .align 5 262__und_svc: 263#ifdef CONFIG_KPROBES 264 @ If a kprobe is about to simulate a "stmdb sp..." instruction, 265 @ it obviously needs free stack space which then will belong to 266 @ the saved context. 267 svc_entry MAX_STACK_SIZE 268#else 269 svc_entry 270#endif 271 272 mov r1, #4 @ PC correction to apply 273 THUMB( tst r5, #PSR_T_BIT ) @ exception taken in Thumb mode? 274 THUMB( movne r1, #2 ) @ if so, fix up PC correction 275 mov r0, sp @ struct pt_regs *regs 276 bl __und_fault 277 278__und_svc_finish: 279 get_thread_info tsk 280 ldr r5, [sp, #S_PSR] @ Get SVC cpsr 281 svc_exit r5 @ return from exception 282 UNWIND(.fnend ) 283ENDPROC(__und_svc) 284 285 .align 5 286__pabt_svc: 287 svc_entry 288 mov r2, sp @ regs 289 pabt_helper 290 svc_exit r5 @ return from exception 291 UNWIND(.fnend ) 292ENDPROC(__pabt_svc) 293 294 .align 5 295__fiq_svc: 296 svc_entry trace=0 297 mov r0, sp @ struct pt_regs *regs 298 bl handle_fiq_as_nmi 299 svc_exit_via_fiq 300 UNWIND(.fnend ) 301ENDPROC(__fiq_svc) 302 303/* 304 * Abort mode handlers 305 */ 306 307@ 308@ Taking a FIQ in abort mode is similar to taking a FIQ in SVC mode 309@ and reuses the same macros. However in abort mode we must also 310@ save/restore lr_abt and spsr_abt to make nested aborts safe. 311@ 312 .align 5 313__fiq_abt: 314 svc_entry trace=0 315 316 ARM( msr cpsr_c, #ABT_MODE | PSR_I_BIT | PSR_F_BIT ) 317 THUMB( mov r0, #ABT_MODE | PSR_I_BIT | PSR_F_BIT ) 318 THUMB( msr cpsr_c, r0 ) 319 mov r1, lr @ Save lr_abt 320 mrs r2, spsr @ Save spsr_abt, abort is now safe 321 ARM( msr cpsr_c, #SVC_MODE | PSR_I_BIT | PSR_F_BIT ) 322 THUMB( mov r0, #SVC_MODE | PSR_I_BIT | PSR_F_BIT ) 323 THUMB( msr cpsr_c, r0 ) 324 stmfd sp!, {r1 - r2} 325 326 add r0, sp, #8 @ struct pt_regs *regs 327 bl handle_fiq_as_nmi 328 329 ldmfd sp!, {r1 - r2} 330 ARM( msr cpsr_c, #ABT_MODE | PSR_I_BIT | PSR_F_BIT ) 331 THUMB( mov r0, #ABT_MODE | PSR_I_BIT | PSR_F_BIT ) 332 THUMB( msr cpsr_c, r0 ) 333 mov lr, r1 @ Restore lr_abt, abort is unsafe 334 msr spsr_cxsf, r2 @ Restore spsr_abt 335 ARM( msr cpsr_c, #SVC_MODE | PSR_I_BIT | PSR_F_BIT ) 336 THUMB( mov r0, #SVC_MODE | PSR_I_BIT | PSR_F_BIT ) 337 THUMB( msr cpsr_c, r0 ) 338 339 svc_exit_via_fiq 340 UNWIND(.fnend ) 341ENDPROC(__fiq_abt) 342 343/* 344 * User mode handlers 345 * 346 * EABI note: sp_svc is always 64-bit aligned here, so should PT_REGS_SIZE 347 */ 348 349#if defined(CONFIG_AEABI) && (__LINUX_ARM_ARCH__ >= 5) && (PT_REGS_SIZE & 7) 350#error "sizeof(struct pt_regs) must be a multiple of 8" 351#endif 352 353 .macro usr_entry, trace=1, uaccess=1 354 UNWIND(.fnstart ) 355 UNWIND(.cantunwind ) @ don't unwind the user space 356 sub sp, sp, #PT_REGS_SIZE 357 ARM( stmib sp, {r1 - r12} ) 358 THUMB( stmia sp, {r0 - r12} ) 359 360 ATRAP( mrc p15, 0, r7, c1, c0, 0) 361 ATRAP( ldr_va r8, cr_alignment) 362 363 ldmia r0, {r3 - r5} 364 add r0, sp, #S_PC @ here for interlock avoidance 365 mov r6, #-1 @ "" "" "" "" 366 367 str r3, [sp] @ save the "real" r0 copied 368 @ from the exception stack 369 370 @ 371 @ We are now ready to fill in the remaining blanks on the stack: 372 @ 373 @ r4 - lr_<exception>, already fixed up for correct return/restart 374 @ r5 - spsr_<exception> 375 @ r6 - orig_r0 (see pt_regs definition in ptrace.h) 376 @ 377 @ Also, separately save sp_usr and lr_usr 378 @ 379 stmia r0, {r4 - r6} 380 ARM( stmdb r0, {sp, lr}^ ) 381 THUMB( store_user_sp_lr r0, r1, S_SP - S_PC ) 382 383 .if \uaccess 384 uaccess_disable ip 385 .endif 386 387 @ Enable the alignment trap while in kernel mode 388 ATRAP( teq r8, r7) 389 ATRAP( mcrne p15, 0, r8, c1, c0, 0) 390 391 reload_current r7, r8 392 393 @ 394 @ Clear FP to mark the first stack frame 395 @ 396 zero_fp 397 398 .if \trace 399#ifdef CONFIG_TRACE_IRQFLAGS 400 bl trace_hardirqs_off 401#endif 402 ct_user_exit save = 0 403 .endif 404 .endm 405 406 .macro kuser_cmpxchg_check 407#if !defined(CONFIG_CPU_32v6K) && defined(CONFIG_KUSER_HELPERS) 408#ifndef CONFIG_MMU 409#warning "NPTL on non MMU needs fixing" 410#else 411 @ Make sure our user space atomic helper is restarted 412 @ if it was interrupted in a critical region. Here we 413 @ perform a quick test inline since it should be false 414 @ 99.9999% of the time. The rest is done out of line. 415 ldr r0, =TASK_SIZE 416 cmp r4, r0 417 blhs kuser_cmpxchg64_fixup 418#endif 419#endif 420 .endm 421 422 .align 5 423__dabt_usr: 424 usr_entry uaccess=0 425 kuser_cmpxchg_check 426 mov r2, sp 427 dabt_helper 428 b ret_from_exception 429 UNWIND(.fnend ) 430ENDPROC(__dabt_usr) 431 432 .align 5 433__irq_usr: 434 usr_entry 435 kuser_cmpxchg_check 436 irq_handler from_user=1 437 get_thread_info tsk 438 mov why, #0 439 b ret_to_user_from_irq 440 UNWIND(.fnend ) 441ENDPROC(__irq_usr) 442 443 .ltorg 444 445 .align 5 446__und_usr: 447 usr_entry uaccess=0 448 449 @ IRQs must be enabled before attempting to read the instruction from 450 @ user space since that could cause a page/translation fault if the 451 @ page table was modified by another CPU. 452 enable_irq 453 454 tst r5, #PSR_T_BIT @ Thumb mode? 455 mov r1, #2 @ set insn size to 2 for Thumb 456 bne 0f @ handle as Thumb undef exception 457#ifdef CONFIG_FPE_NWFPE 458 adr r9, ret_from_exception 459 bl call_fpe @ returns via R9 on success 460#endif 461 mov r1, #4 @ set insn size to 4 for ARM 4620: mov r0, sp 463 uaccess_disable ip 464 bl __und_fault 465 b ret_from_exception 466 UNWIND(.fnend) 467ENDPROC(__und_usr) 468 469 .align 5 470__pabt_usr: 471 usr_entry 472 mov r2, sp @ regs 473 pabt_helper 474 UNWIND(.fnend ) 475 /* fall through */ 476/* 477 * This is the return code to user mode for abort handlers 478 */ 479ENTRY(ret_from_exception) 480 UNWIND(.fnstart ) 481 UNWIND(.cantunwind ) 482 get_thread_info tsk 483 mov why, #0 484 b ret_to_user 485 UNWIND(.fnend ) 486ENDPROC(__pabt_usr) 487ENDPROC(ret_from_exception) 488 489 .align 5 490__fiq_usr: 491 usr_entry trace=0 492 kuser_cmpxchg_check 493 mov r0, sp @ struct pt_regs *regs 494 bl handle_fiq_as_nmi 495 get_thread_info tsk 496 restore_user_regs fast = 0, offset = 0 497 UNWIND(.fnend ) 498ENDPROC(__fiq_usr) 499 500/* 501 * Register switch for ARMv3 and ARMv4 processors 502 * r0 = previous task_struct, r1 = previous thread_info, r2 = next thread_info 503 * previous and next are guaranteed not to be the same. 504 */ 505ENTRY(__switch_to) 506 UNWIND(.fnstart ) 507 UNWIND(.cantunwind ) 508 add ip, r1, #TI_CPU_SAVE 509 ARM( stmia ip!, {r4 - sl, fp, sp, lr} ) @ Store most regs on stack 510 THUMB( stmia ip!, {r4 - sl, fp} ) @ Store most regs on stack 511 THUMB( str sp, [ip], #4 ) 512 THUMB( str lr, [ip], #4 ) 513 ldr r4, [r2, #TI_TP_VALUE] 514 ldr r5, [r2, #TI_TP_VALUE + 4] 515#ifdef CONFIG_CPU_USE_DOMAINS 516 mrc p15, 0, r6, c3, c0, 0 @ Get domain register 517 str r6, [r1, #TI_CPU_DOMAIN] @ Save old domain register 518 ldr r6, [r2, #TI_CPU_DOMAIN] 519#endif 520 switch_tls r1, r4, r5, r3, r7 521#if defined(CONFIG_STACKPROTECTOR) && !defined(CONFIG_SMP) && \ 522 !defined(CONFIG_STACKPROTECTOR_PER_TASK) 523 ldr r8, =__stack_chk_guard 524 .if (TSK_STACK_CANARY > IMM12_MASK) 525 add r9, r2, #TSK_STACK_CANARY & ~IMM12_MASK 526 ldr r9, [r9, #TSK_STACK_CANARY & IMM12_MASK] 527 .else 528 ldr r9, [r2, #TSK_STACK_CANARY & IMM12_MASK] 529 .endif 530#endif 531 mov r7, r2 @ Preserve 'next' 532#ifdef CONFIG_CPU_USE_DOMAINS 533 mcr p15, 0, r6, c3, c0, 0 @ Set domain register 534#endif 535 mov r5, r0 536 add r4, r2, #TI_CPU_SAVE 537 ldr r0, =thread_notify_head 538 mov r1, #THREAD_NOTIFY_SWITCH 539 bl atomic_notifier_call_chain 540#if defined(CONFIG_STACKPROTECTOR) && !defined(CONFIG_SMP) && \ 541 !defined(CONFIG_STACKPROTECTOR_PER_TASK) 542 str r9, [r8] 543#endif 544 mov r0, r5 545#if !defined(CONFIG_THUMB2_KERNEL) && !defined(CONFIG_VMAP_STACK) 546 set_current r7, r8 547 ldmia r4, {r4 - sl, fp, sp, pc} @ Load all regs saved previously 548#else 549 mov r1, r7 550 ldmia r4, {r4 - sl, fp, ip, lr} @ Load all regs saved previously 551#ifdef CONFIG_VMAP_STACK 552 @ 553 @ Do a dummy read from the new stack while running from the old one so 554 @ that we can rely on do_translation_fault() to fix up any stale PMD 555 @ entries covering the vmalloc region. 556 @ 557 ldr r2, [ip] 558#endif 559 560 @ When CONFIG_THREAD_INFO_IN_TASK=n, the update of SP itself is what 561 @ effectuates the task switch, as that is what causes the observable 562 @ values of current and current_thread_info to change. When 563 @ CONFIG_THREAD_INFO_IN_TASK=y, setting current (and therefore 564 @ current_thread_info) is done explicitly, and the update of SP just 565 @ switches us to another stack, with few other side effects. In order 566 @ to prevent this distinction from causing any inconsistencies, let's 567 @ keep the 'set_current' call as close as we can to the update of SP. 568 set_current r1, r2 569 mov sp, ip 570 ret lr 571#endif 572 UNWIND(.fnend ) 573ENDPROC(__switch_to) 574 575#ifdef CONFIG_VMAP_STACK 576 .text 577 .align 2 578__bad_stack: 579 @ 580 @ We've just detected an overflow. We need to load the address of this 581 @ CPU's overflow stack into the stack pointer register. We have only one 582 @ scratch register so let's use a sequence of ADDs including one 583 @ involving the PC, and decorate them with PC-relative group 584 @ relocations. As these are ARM only, switch to ARM mode first. 585 @ 586 @ We enter here with IP clobbered and its value stashed on the mode 587 @ stack. 588 @ 589THUMB( bx pc ) 590THUMB( nop ) 591THUMB( .arm ) 592 ldr_this_cpu_armv6 ip, overflow_stack_ptr 593 594 str sp, [ip, #-4]! @ Preserve original SP value 595 mov sp, ip @ Switch to overflow stack 596 pop {ip} @ Original SP in IP 597 598#if defined(CONFIG_UNWINDER_FRAME_POINTER) && defined(CONFIG_CC_IS_GCC) 599 mov ip, ip @ mov expected by unwinder 600 push {fp, ip, lr, pc} @ GCC flavor frame record 601#else 602 str ip, [sp, #-8]! @ store original SP 603 push {fpreg, lr} @ Clang flavor frame record 604#endif 605UNWIND( ldr ip, [r0, #4] ) @ load exception LR 606UNWIND( str ip, [sp, #12] ) @ store in the frame record 607 ldr ip, [r0, #12] @ reload IP 608 609 @ Store the original GPRs to the new stack. 610 svc_entry uaccess=0, overflow_check=0 611 612UNWIND( .save {sp, pc} ) 613UNWIND( .save {fpreg, lr} ) 614UNWIND( .setfp fpreg, sp ) 615 616 ldr fpreg, [sp, #S_SP] @ Add our frame record 617 @ to the linked list 618#if defined(CONFIG_UNWINDER_FRAME_POINTER) && defined(CONFIG_CC_IS_GCC) 619 ldr r1, [fp, #4] @ reload SP at entry 620 add fp, fp, #12 621#else 622 ldr r1, [fpreg, #8] 623#endif 624 str r1, [sp, #S_SP] @ store in pt_regs 625 626 @ Stash the regs for handle_bad_stack 627 mov r0, sp 628 629 @ Time to die 630 bl handle_bad_stack 631 nop 632UNWIND( .fnend ) 633ENDPROC(__bad_stack) 634#endif 635 636 __INIT 637 638/* 639 * User helpers. 640 * 641 * Each segment is 32-byte aligned and will be moved to the top of the high 642 * vector page. New segments (if ever needed) must be added in front of 643 * existing ones. This mechanism should be used only for things that are 644 * really small and justified, and not be abused freely. 645 * 646 * See Documentation/arch/arm/kernel_user_helpers.rst for formal definitions. 647 */ 648 THUMB( .arm ) 649 650 .macro usr_ret, reg 651#ifdef CONFIG_ARM_THUMB 652 bx \reg 653#else 654 ret \reg 655#endif 656 .endm 657 658 .macro kuser_pad, sym, size 659 .if (. - \sym) & 3 660 .rept 4 - (. - \sym) & 3 661 .byte 0 662 .endr 663 .endif 664 .rept (\size - (. - \sym)) / 4 665 .word 0xe7fddef1 666 .endr 667 .endm 668 669#ifdef CONFIG_KUSER_HELPERS 670 .align 5 671 .globl __kuser_helper_start 672__kuser_helper_start: 673 674/* 675 * Due to the length of some sequences, __kuser_cmpxchg64 spans 2 regular 676 * kuser "slots", therefore 0xffff0f80 is not used as a valid entry point. 677 */ 678 679__kuser_cmpxchg64: @ 0xffff0f60 680 681#if defined(CONFIG_CPU_32v6K) 682 683 stmfd sp!, {r4, r5, r6, r7} 684 ldrd r4, r5, [r0] @ load old val 685 ldrd r6, r7, [r1] @ load new val 686 smp_dmb arm 6871: ldrexd r0, r1, [r2] @ load current val 688 eors r3, r0, r4 @ compare with oldval (1) 689 eorseq r3, r1, r5 @ compare with oldval (2) 690 strexdeq r3, r6, r7, [r2] @ store newval if eq 691 teqeq r3, #1 @ success? 692 beq 1b @ if no then retry 693 smp_dmb arm 694 rsbs r0, r3, #0 @ set returned val and C flag 695 ldmfd sp!, {r4, r5, r6, r7} 696 usr_ret lr 697 698#elif !defined(CONFIG_SMP) 699 700#ifdef CONFIG_MMU 701 702 /* 703 * The only thing that can break atomicity in this cmpxchg64 704 * implementation is either an IRQ or a data abort exception 705 * causing another process/thread to be scheduled in the middle of 706 * the critical sequence. The same strategy as for cmpxchg is used. 707 */ 708 stmfd sp!, {r4, r5, r6, lr} 709 ldmia r0, {r4, r5} @ load old val 710 ldmia r1, {r6, lr} @ load new val 7111: ldmia r2, {r0, r1} @ load current val 712 eors r3, r0, r4 @ compare with oldval (1) 713 eorseq r3, r1, r5 @ compare with oldval (2) 7142: stmiaeq r2, {r6, lr} @ store newval if eq 715 rsbs r0, r3, #0 @ set return val and C flag 716 ldmfd sp!, {r4, r5, r6, pc} 717 718 .text 719kuser_cmpxchg64_fixup: 720 @ Called from kuser_cmpxchg_fixup. 721 @ r4 = address of interrupted insn (must be preserved). 722 @ sp = saved regs. r7 and r8 are clobbered. 723 @ 1b = first critical insn, 2b = last critical insn. 724 @ If r4 >= 1b and r4 <= 2b then saved pc_usr is set to 1b. 725 mov r7, #0xffff0fff 726 sub r7, r7, #(0xffff0fff - (0xffff0f60 + (1b - __kuser_cmpxchg64))) 727 subs r8, r4, r7 728 rsbscs r8, r8, #(2b - 1b) 729 strcs r7, [sp, #S_PC] 730#if __LINUX_ARM_ARCH__ < 6 731 bcc kuser_cmpxchg32_fixup 732#endif 733 ret lr 734 .previous 735 736#else 737#warning "NPTL on non MMU needs fixing" 738 mov r0, #-1 739 adds r0, r0, #0 740 usr_ret lr 741#endif 742 743#else 744#error "incoherent kernel configuration" 745#endif 746 747 kuser_pad __kuser_cmpxchg64, 64 748 749__kuser_memory_barrier: @ 0xffff0fa0 750 smp_dmb arm 751 usr_ret lr 752 753 kuser_pad __kuser_memory_barrier, 32 754 755__kuser_cmpxchg: @ 0xffff0fc0 756 757#if __LINUX_ARM_ARCH__ < 6 758 759#ifdef CONFIG_MMU 760 761 /* 762 * The only thing that can break atomicity in this cmpxchg 763 * implementation is either an IRQ or a data abort exception 764 * causing another process/thread to be scheduled in the middle 765 * of the critical sequence. To prevent this, code is added to 766 * the IRQ and data abort exception handlers to set the pc back 767 * to the beginning of the critical section if it is found to be 768 * within that critical section (see kuser_cmpxchg_fixup). 769 */ 7701: ldr r3, [r2] @ load current val 771 subs r3, r3, r0 @ compare with oldval 7722: streq r1, [r2] @ store newval if eq 773 rsbs r0, r3, #0 @ set return val and C flag 774 usr_ret lr 775 776 .text 777kuser_cmpxchg32_fixup: 778 @ Called from kuser_cmpxchg_check macro. 779 @ r4 = address of interrupted insn (must be preserved). 780 @ sp = saved regs. r7 and r8 are clobbered. 781 @ 1b = first critical insn, 2b = last critical insn. 782 @ If r4 >= 1b and r4 <= 2b then saved pc_usr is set to 1b. 783 mov r7, #0xffff0fff 784 sub r7, r7, #(0xffff0fff - (0xffff0fc0 + (1b - __kuser_cmpxchg))) 785 subs r8, r4, r7 786 rsbscs r8, r8, #(2b - 1b) 787 strcs r7, [sp, #S_PC] 788 ret lr 789 .previous 790 791#else 792#warning "NPTL on non MMU needs fixing" 793 mov r0, #-1 794 adds r0, r0, #0 795 usr_ret lr 796#endif 797 798#else 799 800 smp_dmb arm 8011: ldrex r3, [r2] 802 subs r3, r3, r0 803 strexeq r3, r1, [r2] 804 teqeq r3, #1 805 beq 1b 806 rsbs r0, r3, #0 807 /* beware -- each __kuser slot must be 8 instructions max */ 808 ALT_SMP(b __kuser_memory_barrier) 809 ALT_UP(usr_ret lr) 810 811#endif 812 813 kuser_pad __kuser_cmpxchg, 32 814 815__kuser_get_tls: @ 0xffff0fe0 816 ldr r0, [pc, #(16 - 8)] @ read TLS, set in kuser_get_tls_init 817 usr_ret lr 818 mrc p15, 0, r0, c13, c0, 3 @ 0xffff0fe8 hardware TLS code 819 kuser_pad __kuser_get_tls, 16 820 .rep 3 821 .word 0 @ 0xffff0ff0 software TLS value, then 822 .endr @ pad up to __kuser_helper_version 823 824__kuser_helper_version: @ 0xffff0ffc 825 .word ((__kuser_helper_end - __kuser_helper_start) >> 5) 826 827 .globl __kuser_helper_end 828__kuser_helper_end: 829 830#endif 831 832 THUMB( .thumb ) 833 834/* 835 * Vector stubs. 836 * 837 * This code is copied to 0xffff1000 so we can use branches in the 838 * vectors, rather than ldr's. Note that this code must not exceed 839 * a page size. 840 * 841 * Common stub entry macro: 842 * Enter in IRQ mode, spsr = SVC/USR CPSR, lr = SVC/USR PC 843 * 844 * SP points to a minimal amount of processor-private memory, the address 845 * of which is copied into r0 for the mode specific abort handler. 846 */ 847 .macro vector_stub, name, mode, correction=0 848 .align 5 849#ifdef CONFIG_HARDEN_BRANCH_HISTORY 850vector_bhb_bpiall_\name: 851 mcr p15, 0, r0, c7, c5, 6 @ BPIALL 852 @ isb not needed due to "movs pc, lr" in the vector stub 853 @ which gives a "context synchronisation". 854#endif 855 856vector_\name: 857 .if \correction 858 sub lr, lr, #\correction 859 .endif 860 861 @ Save r0, lr_<exception> (parent PC) 862 stmia sp, {r0, lr} @ save r0, lr 863 864 @ Save spsr_<exception> (parent CPSR) 865.Lvec_\name: 866 mrs lr, spsr 867 str lr, [sp, #8] @ save spsr 868 869 @ 870 @ Prepare for SVC32 mode. IRQs remain disabled. 871 @ 872 mrs r0, cpsr 873 eor r0, r0, #(\mode ^ SVC_MODE | PSR_ISETSTATE) 874 msr spsr_cxsf, r0 875 876 @ 877 @ the branch table must immediately follow this code 878 @ 879 and lr, lr, #0x0f 880 THUMB( adr r0, 1f ) 881 THUMB( ldr lr, [r0, lr, lsl #2] ) 882 mov r0, sp 883 ARM( ldr lr, [pc, lr, lsl #2] ) 884 movs pc, lr @ branch to handler in SVC mode 885ENDPROC(vector_\name) 886 887#ifdef CONFIG_HARDEN_BRANCH_HISTORY 888 .subsection 1 889 .align 5 890vector_bhb_loop8_\name: 891 .if \correction 892 sub lr, lr, #\correction 893 .endif 894 895 @ Save r0, lr_<exception> (parent PC) 896 stmia sp, {r0, lr} 897 898 @ bhb workaround 899 mov r0, #8 9003: W(b) . + 4 901 subs r0, r0, #1 902 bne 3b 903 dsb nsh 904 @ isb not needed due to "movs pc, lr" in the vector stub 905 @ which gives a "context synchronisation". 906 b .Lvec_\name 907ENDPROC(vector_bhb_loop8_\name) 908 .previous 909#endif 910 911 .align 2 912 @ handler addresses follow this label 9131: 914 .endm 915 916 .section .stubs, "ax", %progbits 917 @ These need to remain at the start of the section so that 918 @ they are in range of the 'SWI' entries in the vector tables 919 @ located 4k down. 920.L__vector_swi: 921 .word vector_swi 922#ifdef CONFIG_HARDEN_BRANCH_HISTORY 923.L__vector_bhb_loop8_swi: 924 .word vector_bhb_loop8_swi 925.L__vector_bhb_bpiall_swi: 926 .word vector_bhb_bpiall_swi 927#endif 928 929vector_rst: 930 ARM( swi SYS_ERROR0 ) 931 THUMB( svc #0 ) 932 THUMB( nop ) 933 b vector_und 934 935/* 936 * Interrupt dispatcher 937 */ 938 vector_stub irq, IRQ_MODE, 4 939 940 .long __irq_usr @ 0 (USR_26 / USR_32) 941 .long __irq_invalid @ 1 (FIQ_26 / FIQ_32) 942 .long __irq_invalid @ 2 (IRQ_26 / IRQ_32) 943 .long __irq_svc @ 3 (SVC_26 / SVC_32) 944 .long __irq_invalid @ 4 945 .long __irq_invalid @ 5 946 .long __irq_invalid @ 6 947 .long __irq_invalid @ 7 948 .long __irq_invalid @ 8 949 .long __irq_invalid @ 9 950 .long __irq_invalid @ a 951 .long __irq_invalid @ b 952 .long __irq_invalid @ c 953 .long __irq_invalid @ d 954 .long __irq_invalid @ e 955 .long __irq_invalid @ f 956 957/* 958 * Data abort dispatcher 959 * Enter in ABT mode, spsr = USR CPSR, lr = USR PC 960 */ 961 vector_stub dabt, ABT_MODE, 8 962 963 .long __dabt_usr @ 0 (USR_26 / USR_32) 964 .long __dabt_invalid @ 1 (FIQ_26 / FIQ_32) 965 .long __dabt_invalid @ 2 (IRQ_26 / IRQ_32) 966 .long __dabt_svc @ 3 (SVC_26 / SVC_32) 967 .long __dabt_invalid @ 4 968 .long __dabt_invalid @ 5 969 .long __dabt_invalid @ 6 970 .long __dabt_invalid @ 7 971 .long __dabt_invalid @ 8 972 .long __dabt_invalid @ 9 973 .long __dabt_invalid @ a 974 .long __dabt_invalid @ b 975 .long __dabt_invalid @ c 976 .long __dabt_invalid @ d 977 .long __dabt_invalid @ e 978 .long __dabt_invalid @ f 979 980/* 981 * Prefetch abort dispatcher 982 * Enter in ABT mode, spsr = USR CPSR, lr = USR PC 983 */ 984 vector_stub pabt, ABT_MODE, 4 985 986 .long __pabt_usr @ 0 (USR_26 / USR_32) 987 .long __pabt_invalid @ 1 (FIQ_26 / FIQ_32) 988 .long __pabt_invalid @ 2 (IRQ_26 / IRQ_32) 989 .long __pabt_svc @ 3 (SVC_26 / SVC_32) 990 .long __pabt_invalid @ 4 991 .long __pabt_invalid @ 5 992 .long __pabt_invalid @ 6 993 .long __pabt_invalid @ 7 994 .long __pabt_invalid @ 8 995 .long __pabt_invalid @ 9 996 .long __pabt_invalid @ a 997 .long __pabt_invalid @ b 998 .long __pabt_invalid @ c 999 .long __pabt_invalid @ d 1000 .long __pabt_invalid @ e 1001 .long __pabt_invalid @ f 1002 1003/* 1004 * Undef instr entry dispatcher 1005 * Enter in UND mode, spsr = SVC/USR CPSR, lr = SVC/USR PC 1006 */ 1007 vector_stub und, UND_MODE 1008 1009 .long __und_usr @ 0 (USR_26 / USR_32) 1010 .long __und_invalid @ 1 (FIQ_26 / FIQ_32) 1011 .long __und_invalid @ 2 (IRQ_26 / IRQ_32) 1012 .long __und_svc @ 3 (SVC_26 / SVC_32) 1013 .long __und_invalid @ 4 1014 .long __und_invalid @ 5 1015 .long __und_invalid @ 6 1016 .long __und_invalid @ 7 1017 .long __und_invalid @ 8 1018 .long __und_invalid @ 9 1019 .long __und_invalid @ a 1020 .long __und_invalid @ b 1021 .long __und_invalid @ c 1022 .long __und_invalid @ d 1023 .long __und_invalid @ e 1024 .long __und_invalid @ f 1025 1026 .align 5 1027 1028/*============================================================================= 1029 * Address exception handler 1030 *----------------------------------------------------------------------------- 1031 * These aren't too critical. 1032 * (they're not supposed to happen, and won't happen in 32-bit data mode). 1033 */ 1034 1035vector_addrexcptn: 1036 b vector_addrexcptn 1037 1038/*============================================================================= 1039 * FIQ "NMI" handler 1040 *----------------------------------------------------------------------------- 1041 * Handle a FIQ using the SVC stack allowing FIQ act like NMI on x86 1042 * systems. This must be the last vector stub, so lets place it in its own 1043 * subsection. 1044 */ 1045 .subsection 2 1046 vector_stub fiq, FIQ_MODE, 4 1047 1048 .long __fiq_usr @ 0 (USR_26 / USR_32) 1049 .long __fiq_svc @ 1 (FIQ_26 / FIQ_32) 1050 .long __fiq_svc @ 2 (IRQ_26 / IRQ_32) 1051 .long __fiq_svc @ 3 (SVC_26 / SVC_32) 1052 .long __fiq_svc @ 4 1053 .long __fiq_svc @ 5 1054 .long __fiq_svc @ 6 1055 .long __fiq_abt @ 7 1056 .long __fiq_svc @ 8 1057 .long __fiq_svc @ 9 1058 .long __fiq_svc @ a 1059 .long __fiq_svc @ b 1060 .long __fiq_svc @ c 1061 .long __fiq_svc @ d 1062 .long __fiq_svc @ e 1063 .long __fiq_svc @ f 1064 1065 .globl vector_fiq 1066 1067 .section .vectors, "ax", %progbits 1068 W(b) vector_rst 1069 W(b) vector_und 1070ARM( .reloc ., R_ARM_LDR_PC_G0, .L__vector_swi ) 1071THUMB( .reloc ., R_ARM_THM_PC12, .L__vector_swi ) 1072 W(ldr) pc, . 1073 W(b) vector_pabt 1074 W(b) vector_dabt 1075 W(b) vector_addrexcptn 1076 W(b) vector_irq 1077 W(b) vector_fiq 1078 1079#ifdef CONFIG_HARDEN_BRANCH_HISTORY 1080 .section .vectors.bhb.loop8, "ax", %progbits 1081 W(b) vector_rst 1082 W(b) vector_bhb_loop8_und 1083ARM( .reloc ., R_ARM_LDR_PC_G0, .L__vector_bhb_loop8_swi ) 1084THUMB( .reloc ., R_ARM_THM_PC12, .L__vector_bhb_loop8_swi ) 1085 W(ldr) pc, . 1086 W(b) vector_bhb_loop8_pabt 1087 W(b) vector_bhb_loop8_dabt 1088 W(b) vector_addrexcptn 1089 W(b) vector_bhb_loop8_irq 1090 W(b) vector_bhb_loop8_fiq 1091 1092 .section .vectors.bhb.bpiall, "ax", %progbits 1093 W(b) vector_rst 1094 W(b) vector_bhb_bpiall_und 1095ARM( .reloc ., R_ARM_LDR_PC_G0, .L__vector_bhb_bpiall_swi ) 1096THUMB( .reloc ., R_ARM_THM_PC12, .L__vector_bhb_bpiall_swi ) 1097 W(ldr) pc, . 1098 W(b) vector_bhb_bpiall_pabt 1099 W(b) vector_bhb_bpiall_dabt 1100 W(b) vector_addrexcptn 1101 W(b) vector_bhb_bpiall_irq 1102 W(b) vector_bhb_bpiall_fiq 1103#endif 1104 1105 .data 1106 .align 2 1107 1108 .globl cr_alignment 1109cr_alignment: 1110 .space 4 1111
