| blob | b3fb8c9e1ff2d75f15666a9233dee2d1b3ccb6bc |
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 */
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>
32 #include "entry-header.S"
33 #include <asm/entry-macro-multi.S>
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
47 9997:
48 .endm
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
61 .macro dabt_helper
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
82 #ifdef CONFIG_KPROBES
83 .section .kprobes.text,"ax",%progbits
84 #else
85 .text
86 #endif
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
100 __pabt_invalid:
101 inv_entry BAD_PREFETCH
102 b common_invalid
103 ENDPROC(__pabt_invalid)
105 __dabt_invalid:
106 inv_entry BAD_DATA
107 b common_invalid
108 ENDPROC(__dabt_invalid)
110 __irq_invalid:
111 inv_entry BAD_IRQ
112 b common_invalid
113 ENDPROC(__irq_invalid)
115 __und_invalid:
116 inv_entry BAD_UNDEFINSTR
118 @
119 @ XXX fall through to common_invalid
120 @
122 @
123 @ common_invalid - generic code for failed exception (re-entrant version of handlers)
124 @
125 common_invalid:
126 zero_fp
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"
135 mov r0, sp
136 b bad_mode
137 ENDPROC(__und_invalid)
139 /*
140 * SVC mode handlers
141 */
143 #if defined(CONFIG_AEABI) && (__LINUX_ARM_ARCH__ >= 5)
144 #define SPFIX(code...) code
145 #else
146 #define SPFIX(code...)
147 #endif
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}
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
172 mov r3, lr
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}
185 #ifdef CONFIG_TRACE_IRQFLAGS
186 bl trace_hardirqs_off
187 #endif
188 .endm
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 )
198 ENDPROC(__dabt_svc)
200 .align 5
201 __irq_svc:
202 svc_entry
203 irq_handler
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
215 svc_exit r5, irq = 1 @ return from exception
216 UNWIND(.fnend )
217 ENDPROC(__irq_svc)
219 .ltorg
221 #ifdef CONFIG_PREEMPT
222 svc_preempt:
223 mov r8, lr
224 1: 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
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
242 ENDPROC(__und_fault)
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
277 mov r1, #4 @ PC correction to apply
278 __und_svc_fault:
279 mov r0, sp @ struct pt_regs *regs
280 bl __und_fault
282 __und_svc_finish:
283 ldr r5, [sp, #S_PSR] @ Get SVC cpsr
284 svc_exit r5 @ return from exception
285 UNWIND(.fnend )
286 ENDPROC(__und_svc)
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 )
295 ENDPROC(__pabt_svc)
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
307 /*
308 * User mode handlers
309 *
310 * EABI note: sp_svc is always 64-bit aligned here, so should S_FRAME_SIZE
311 */
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
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} )
324 ldmia r0, {r3 - r5}
325 add r0, sp, #S_PC @ here for interlock avoidance
326 mov r6, #-1 @ "" "" "" ""
328 str r3, [sp] @ save the "real" r0 copied
329 @ from the exception stack
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 )
344 @
345 @ Enable the alignment trap while in kernel mode
346 @
347 alignment_trap r0
349 @
350 @ Clear FP to mark the first stack frame
351 @
352 zero_fp
354 #ifdef CONFIG_IRQSOFF_TRACER
355 bl trace_hardirqs_off
356 #endif
357 ct_user_exit save = 0
358 .endm
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
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 )
384 ENDPROC(__dabt_usr)
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 )
395 ENDPROC(__irq_usr)
397 .ltorg
399 .align 5
400 __und_usr:
401 usr_entry
403 mov r2, r4
404 mov r3, r5
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)
416 tst r3, #PSR_T_BIT @ Thumb mode?
417 bne __und_usr_thumb
418 sub r4, r2, #4 @ ARM instr at LR - 4
419 1: ldrt r0, [r4]
420 ARM_BE8(rev r0, r0) @ little endian instruction
422 @ r0 = 32-bit ARM instruction which caused the exception
423 @ r2 = PC value for the following instruction (:= regs->ARM_pc)
424 @ r4 = PC value for the faulting instruction
425 @ lr = 32-bit undefined instruction function
426 adr lr, BSYM(__und_usr_fault_32)
427 b call_fpe
429 __und_usr_thumb:
430 @ Thumb instruction
431 sub r4, r2, #2 @ First half of thumb instr at LR - 2
432 #if CONFIG_ARM_THUMB && __LINUX_ARM_ARCH__ >= 6 && CONFIG_CPU_V7
433 /*
434 * Thumb-2 instruction handling. Note that because pre-v6 and >= v6 platforms
435 * can never be supported in a single kernel, this code is not applicable at
436 * all when __LINUX_ARM_ARCH__ < 6. This allows simplifying assumptions to be
437 * made about .arch directives.
438 */
439 #if __LINUX_ARM_ARCH__ < 7
440 /* If the target CPU may not be Thumb-2-capable, a run-time check is needed: */
441 #define NEED_CPU_ARCHITECTURE
442 ldr r5, .LCcpu_architecture
443 ldr r5, [r5]
444 cmp r5, #CPU_ARCH_ARMv7
445 blo __und_usr_fault_16 @ 16bit undefined instruction
446 /*
447 * The following code won't get run unless the running CPU really is v7, so
448 * coding round the lack of ldrht on older arches is pointless. Temporarily
449 * override the assembler target arch with the minimum required instead:
450 */
451 .arch armv6t2
452 #endif
453 2: ldrht r5, [r4]
454 cmp r5, #0xe800 @ 32bit instruction if xx != 0
455 blo __und_usr_fault_16 @ 16bit undefined instruction
456 3: ldrht r0, [r2]
457 add r2, r2, #2 @ r2 is PC + 2, make it PC + 4
458 str r2, [sp, #S_PC] @ it's a 2x16bit instr, update
459 orr r0, r0, r5, lsl #16
460 adr lr, BSYM(__und_usr_fault_32)
461 @ r0 = the two 16-bit Thumb instructions which caused the exception
462 @ r2 = PC value for the following Thumb instruction (:= regs->ARM_pc)
463 @ r4 = PC value for the first 16-bit Thumb instruction
464 @ lr = 32bit undefined instruction function
466 #if __LINUX_ARM_ARCH__ < 7
467 /* If the target arch was overridden, change it back: */
468 #ifdef CONFIG_CPU_32v6K
469 .arch armv6k
470 #else
471 .arch armv6
472 #endif
473 #endif /* __LINUX_ARM_ARCH__ < 7 */
474 #else /* !(CONFIG_ARM_THUMB && __LINUX_ARM_ARCH__ >= 6 && CONFIG_CPU_V7) */
475 b __und_usr_fault_16
476 #endif
477 UNWIND(.fnend)
478 ENDPROC(__und_usr)
480 /*
481 * The out of line fixup for the ldrt instructions above.
482 */
483 .pushsection .fixup, "ax"
484 .align 2
485 4: mov pc, r9
486 .popsection
487 .pushsection __ex_table,"a"
488 .long 1b, 4b
489 #if CONFIG_ARM_THUMB && __LINUX_ARM_ARCH__ >= 6 && CONFIG_CPU_V7
490 .long 2b, 4b
491 .long 3b, 4b
492 #endif
493 .popsection
495 /*
496 * Check whether the instruction is a co-processor instruction.
497 * If yes, we need to call the relevant co-processor handler.
498 *
499 * Note that we don't do a full check here for the co-processor
500 * instructions; all instructions with bit 27 set are well
501 * defined. The only instructions that should fault are the
502 * co-processor instructions. However, we have to watch out
503 * for the ARM6/ARM7 SWI bug.
504 *
505 * NEON is a special case that has to be handled here. Not all
506 * NEON instructions are co-processor instructions, so we have
507 * to make a special case of checking for them. Plus, there's
508 * five groups of them, so we have a table of mask/opcode pairs
509 * to check against, and if any match then we branch off into the
510 * NEON handler code.
511 *
512 * Emulators may wish to make use of the following registers:
513 * r0 = instruction opcode (32-bit ARM or two 16-bit Thumb)
514 * r2 = PC value to resume execution after successful emulation
515 * r9 = normal "successful" return address
516 * r10 = this threads thread_info structure
517 * lr = unrecognised instruction return address
518 * IRQs disabled, FIQs enabled.
519 */
520 @
521 @ Fall-through from Thumb-2 __und_usr
522 @
523 #ifdef CONFIG_NEON
524 get_thread_info r10 @ get current thread
525 adr r6, .LCneon_thumb_opcodes
526 b 2f
527 #endif
528 call_fpe:
529 get_thread_info r10 @ get current thread
530 #ifdef CONFIG_NEON
531 adr r6, .LCneon_arm_opcodes
532 2: ldr r5, [r6], #4 @ mask value
533 ldr r7, [r6], #4 @ opcode bits matching in mask
534 cmp r5, #0 @ end mask?
535 beq 1f
536 and r8, r0, r5
537 cmp r8, r7 @ NEON instruction?
538 bne 2b
539 mov r7, #1
540 strb r7, [r10, #TI_USED_CP + 10] @ mark CP#10 as used
541 strb r7, [r10, #TI_USED_CP + 11] @ mark CP#11 as used
542 b do_vfp @ let VFP handler handle this
543 1:
544 #endif
545 tst r0, #0x08000000 @ only CDP/CPRT/LDC/STC have bit 27
546 tstne r0, #0x04000000 @ bit 26 set on both ARM and Thumb-2
547 moveq pc, lr
548 and r8, r0, #0x00000f00 @ mask out CP number
549 THUMB( lsr r8, r8, #8 )
550 mov r7, #1
551 add r6, r10, #TI_USED_CP
552 ARM( strb r7, [r6, r8, lsr #8] ) @ set appropriate used_cp[]
553 THUMB( strb r7, [r6, r8] ) @ set appropriate used_cp[]
554 #ifdef CONFIG_IWMMXT
555 @ Test if we need to give access to iWMMXt coprocessors
556 ldr r5, [r10, #TI_FLAGS]
557 rsbs r7, r8, #(1 << 8) @ CP 0 or 1 only
558 movcss r7, r5, lsr #(TIF_USING_IWMMXT + 1)
559 bcs iwmmxt_task_enable
560 #endif
561 ARM( add pc, pc, r8, lsr #6 )
562 THUMB( lsl r8, r8, #2 )
563 THUMB( add pc, r8 )
564 nop
566 movw_pc lr @ CP#0
567 W(b) do_fpe @ CP#1 (FPE)
568 W(b) do_fpe @ CP#2 (FPE)
569 movw_pc lr @ CP#3
570 #ifdef CONFIG_CRUNCH
571 b crunch_task_enable @ CP#4 (MaverickCrunch)
572 b crunch_task_enable @ CP#5 (MaverickCrunch)
573 b crunch_task_enable @ CP#6 (MaverickCrunch)
574 #else
575 movw_pc lr @ CP#4
576 movw_pc lr @ CP#5
577 movw_pc lr @ CP#6
578 #endif
579 movw_pc lr @ CP#7
580 movw_pc lr @ CP#8
581 movw_pc lr @ CP#9
582 #ifdef CONFIG_VFP
583 W(b) do_vfp @ CP#10 (VFP)
584 W(b) do_vfp @ CP#11 (VFP)
585 #else
586 movw_pc lr @ CP#10 (VFP)
587 movw_pc lr @ CP#11 (VFP)
588 #endif
589 movw_pc lr @ CP#12
590 movw_pc lr @ CP#13
591 movw_pc lr @ CP#14 (Debug)
592 movw_pc lr @ CP#15 (Control)
594 #ifdef NEED_CPU_ARCHITECTURE
595 .align 2
596 .LCcpu_architecture:
597 .word __cpu_architecture
598 #endif
600 #ifdef CONFIG_NEON
601 .align 6
603 .LCneon_arm_opcodes:
604 .word 0xfe000000 @ mask
605 .word 0xf2000000 @ opcode
607 .word 0xff100000 @ mask
608 .word 0xf4000000 @ opcode
610 .word 0x00000000 @ mask
611 .word 0x00000000 @ opcode
613 .LCneon_thumb_opcodes:
614 .word 0xef000000 @ mask
615 .word 0xef000000 @ opcode
617 .word 0xff100000 @ mask
618 .word 0xf9000000 @ opcode
620 .word 0x00000000 @ mask
621 .word 0x00000000 @ opcode
622 #endif
624 do_fpe:
625 enable_irq
626 ldr r4, .LCfp
627 add r10, r10, #TI_FPSTATE @ r10 = workspace
628 ldr pc, [r4] @ Call FP module USR entry point
630 /*
631 * The FP module is called with these registers set:
632 * r0 = instruction
633 * r2 = PC+4
634 * r9 = normal "successful" return address
635 * r10 = FP workspace
636 * lr = unrecognised FP instruction return address
637 */
639 .pushsection .data
640 ENTRY(fp_enter)
641 .word no_fp
642 .popsection
644 ENTRY(no_fp)
645 mov pc, lr
646 ENDPROC(no_fp)
648 __und_usr_fault_32:
649 mov r1, #4
650 b 1f
651 __und_usr_fault_16:
652 mov r1, #2
653 1: enable_irq
654 mov r0, sp
655 adr lr, BSYM(ret_from_exception)
656 b __und_fault
657 ENDPROC(__und_usr_fault_32)
658 ENDPROC(__und_usr_fault_16)
660 .align 5
661 __pabt_usr:
662 usr_entry
663 mov r2, sp @ regs
664 pabt_helper
665 UNWIND(.fnend )
666 /* fall through */
667 /*
668 * This is the return code to user mode for abort handlers
669 */
670 ENTRY(ret_from_exception)
671 UNWIND(.fnstart )
672 UNWIND(.cantunwind )
673 get_thread_info tsk
674 mov why, #0
675 b ret_to_user
676 UNWIND(.fnend )
677 ENDPROC(__pabt_usr)
678 ENDPROC(ret_from_exception)
680 /*
681 * Register switch for ARMv3 and ARMv4 processors
682 * r0 = previous task_struct, r1 = previous thread_info, r2 = next thread_info
683 * previous and next are guaranteed not to be the same.
684 */
685 ENTRY(__switch_to)
686 UNWIND(.fnstart )
687 UNWIND(.cantunwind )
688 add ip, r1, #TI_CPU_SAVE
689 ARM( stmia ip!, {r4 - sl, fp, sp, lr} ) @ Store most regs on stack
690 THUMB( stmia ip!, {r4 - sl, fp} ) @ Store most regs on stack
691 THUMB( str sp, [ip], #4 )
692 THUMB( str lr, [ip], #4 )
693 ldr r4, [r2, #TI_TP_VALUE]
694 ldr r5, [r2, #TI_TP_VALUE + 4]
695 #ifdef CONFIG_CPU_USE_DOMAINS
696 ldr r6, [r2, #TI_CPU_DOMAIN]
697 #endif
698 switch_tls r1, r4, r5, r3, r7
699 #if defined(CONFIG_CC_STACKPROTECTOR) && !defined(CONFIG_SMP)
700 ldr r7, [r2, #TI_TASK]
701 ldr r8, =__stack_chk_guard
702 ldr r7, [r7, #TSK_STACK_CANARY]
703 #endif
704 #ifdef CONFIG_CPU_USE_DOMAINS
705 mcr p15, 0, r6, c3, c0, 0 @ Set domain register
706 #endif
707 mov r5, r0
708 add r4, r2, #TI_CPU_SAVE
709 ldr r0, =thread_notify_head
710 mov r1, #THREAD_NOTIFY_SWITCH
711 bl atomic_notifier_call_chain
712 #if defined(CONFIG_CC_STACKPROTECTOR) && !defined(CONFIG_SMP)
713 str r7, [r8]
714 #endif
715 THUMB( mov ip, r4 )
716 mov r0, r5
717 ARM( ldmia r4, {r4 - sl, fp, sp, pc} ) @ Load all regs saved previously
718 THUMB( ldmia ip!, {r4 - sl, fp} ) @ Load all regs saved previously
719 THUMB( ldr sp, [ip], #4 )
720 THUMB( ldr pc, [ip] )
721 UNWIND(.fnend )
722 ENDPROC(__switch_to)
724 __INIT
726 /*
727 * User helpers.
728 *
729 * Each segment is 32-byte aligned and will be moved to the top of the high
730 * vector page. New segments (if ever needed) must be added in front of
731 * existing ones. This mechanism should be used only for things that are
732 * really small and justified, and not be abused freely.
733 *
734 * See Documentation/arm/kernel_user_helpers.txt for formal definitions.
735 */
736 THUMB( .arm )
738 .macro usr_ret, reg
739 #ifdef CONFIG_ARM_THUMB
740 bx \reg
741 #else
742 mov pc, \reg
743 #endif
744 .endm
746 .macro kuser_pad, sym, size
747 .if (. - \sym) & 3
748 .rept 4 - (. - \sym) & 3
749 .byte 0
750 .endr
751 .endif
752 .rept (\size - (. - \sym)) / 4
753 .word 0xe7fddef1
754 .endr
755 .endm
757 #ifdef CONFIG_KUSER_HELPERS
758 .align 5
759 .globl __kuser_helper_start
760 __kuser_helper_start:
762 /*
763 * Due to the length of some sequences, __kuser_cmpxchg64 spans 2 regular
764 * kuser "slots", therefore 0xffff0f80 is not used as a valid entry point.
765 */
767 __kuser_cmpxchg64: @ 0xffff0f60
769 #if defined(CONFIG_NEEDS_SYSCALL_FOR_CMPXCHG)
771 /*
772 * Poor you. No fast solution possible...
773 * The kernel itself must perform the operation.
774 * A special ghost syscall is used for that (see traps.c).
775 */
776 stmfd sp!, {r7, lr}
777 ldr r7, 1f @ it's 20 bits
778 swi __ARM_NR_cmpxchg64
779 ldmfd sp!, {r7, pc}
780 1: .word __ARM_NR_cmpxchg64
782 #elif defined(CONFIG_CPU_32v6K)
784 stmfd sp!, {r4, r5, r6, r7}
785 ldrd r4, r5, [r0] @ load old val
786 ldrd r6, r7, [r1] @ load new val
787 smp_dmb arm
788 1: ldrexd r0, r1, [r2] @ load current val
789 eors r3, r0, r4 @ compare with oldval (1)
790 eoreqs r3, r1, r5 @ compare with oldval (2)
791 strexdeq r3, r6, r7, [r2] @ store newval if eq
792 teqeq r3, #1 @ success?
793 beq 1b @ if no then retry
794 smp_dmb arm
795 rsbs r0, r3, #0 @ set returned val and C flag
796 ldmfd sp!, {r4, r5, r6, r7}
797 usr_ret lr
799 #elif !defined(CONFIG_SMP)
801 #ifdef CONFIG_MMU
803 /*
804 * The only thing that can break atomicity in this cmpxchg64
805 * implementation is either an IRQ or a data abort exception
806 * causing another process/thread to be scheduled in the middle of
807 * the critical sequence. The same strategy as for cmpxchg is used.
808 */
809 stmfd sp!, {r4, r5, r6, lr}
810 ldmia r0, {r4, r5} @ load old val
811 ldmia r1, {r6, lr} @ load new val
812 1: ldmia r2, {r0, r1} @ load current val
813 eors r3, r0, r4 @ compare with oldval (1)
814 eoreqs r3, r1, r5 @ compare with oldval (2)
815 2: stmeqia r2, {r6, lr} @ store newval if eq
816 rsbs r0, r3, #0 @ set return val and C flag
817 ldmfd sp!, {r4, r5, r6, pc}
819 .text
820 kuser_cmpxchg64_fixup:
821 @ Called from kuser_cmpxchg_fixup.
822 @ r4 = address of interrupted insn (must be preserved).
823 @ sp = saved regs. r7 and r8 are clobbered.
824 @ 1b = first critical insn, 2b = last critical insn.
825 @ If r4 >= 1b and r4 <= 2b then saved pc_usr is set to 1b.
826 mov r7, #0xffff0fff
827 sub r7, r7, #(0xffff0fff - (0xffff0f60 + (1b - __kuser_cmpxchg64)))
828 subs r8, r4, r7
829 rsbcss r8, r8, #(2b - 1b)
830 strcs r7, [sp, #S_PC]
831 #if __LINUX_ARM_ARCH__ < 6
832 bcc kuser_cmpxchg32_fixup
833 #endif
834 mov pc, lr
835 .previous
837 #else
838 #warning "NPTL on non MMU needs fixing"
839 mov r0, #-1
840 adds r0, r0, #0
841 usr_ret lr
842 #endif
844 #else
845 #error "incoherent kernel configuration"
846 #endif
848 kuser_pad __kuser_cmpxchg64, 64
850 __kuser_memory_barrier: @ 0xffff0fa0
851 smp_dmb arm
852 usr_ret lr
854 kuser_pad __kuser_memory_barrier, 32
856 __kuser_cmpxchg: @ 0xffff0fc0
858 #if defined(CONFIG_NEEDS_SYSCALL_FOR_CMPXCHG)
860 /*
861 * Poor you. No fast solution possible...
862 * The kernel itself must perform the operation.
863 * A special ghost syscall is used for that (see traps.c).
864 */
865 stmfd sp!, {r7, lr}
866 ldr r7, 1f @ it's 20 bits
867 swi __ARM_NR_cmpxchg
868 ldmfd sp!, {r7, pc}
869 1: .word __ARM_NR_cmpxchg
871 #elif __LINUX_ARM_ARCH__ < 6
873 #ifdef CONFIG_MMU
875 /*
876 * The only thing that can break atomicity in this cmpxchg
877 * implementation is either an IRQ or a data abort exception
878 * causing another process/thread to be scheduled in the middle
879 * of the critical sequence. To prevent this, code is added to
880 * the IRQ and data abort exception handlers to set the pc back
881 * to the beginning of the critical section if it is found to be
882 * within that critical section (see kuser_cmpxchg_fixup).
883 */
884 1: ldr r3, [r2] @ load current val
885 subs r3, r3, r0 @ compare with oldval
886 2: streq r1, [r2] @ store newval if eq
887 rsbs r0, r3, #0 @ set return val and C flag
888 usr_ret lr
890 .text
891 kuser_cmpxchg32_fixup:
892 @ Called from kuser_cmpxchg_check macro.
893 @ r4 = address of interrupted insn (must be preserved).
894 @ sp = saved regs. r7 and r8 are clobbered.
895 @ 1b = first critical insn, 2b = last critical insn.
896 @ If r4 >= 1b and r4 <= 2b then saved pc_usr is set to 1b.
897 mov r7, #0xffff0fff
898 sub r7, r7, #(0xffff0fff - (0xffff0fc0 + (1b - __kuser_cmpxchg)))
899 subs r8, r4, r7
900 rsbcss r8, r8, #(2b - 1b)
901 strcs r7, [sp, #S_PC]
902 mov pc, lr
903 .previous
905 #else
906 #warning "NPTL on non MMU needs fixing"
907 mov r0, #-1
908 adds r0, r0, #0
909 usr_ret lr
910 #endif
912 #else
914 smp_dmb arm
915 1: ldrex r3, [r2]
916 subs r3, r3, r0
917 strexeq r3, r1, [r2]
918 teqeq r3, #1
919 beq 1b
920 rsbs r0, r3, #0
921 /* beware -- each __kuser slot must be 8 instructions max */
922 ALT_SMP(b __kuser_memory_barrier)
923 ALT_UP(usr_ret lr)
925 #endif
927 kuser_pad __kuser_cmpxchg, 32
929 __kuser_get_tls: @ 0xffff0fe0
930 ldr r0, [pc, #(16 - 8)] @ read TLS, set in kuser_get_tls_init
931 usr_ret lr
932 mrc p15, 0, r0, c13, c0, 3 @ 0xffff0fe8 hardware TLS code
933 kuser_pad __kuser_get_tls, 16
934 .rep 3
935 .word 0 @ 0xffff0ff0 software TLS value, then
936 .endr @ pad up to __kuser_helper_version
938 __kuser_helper_version: @ 0xffff0ffc
939 .word ((__kuser_helper_end - __kuser_helper_start) >> 5)
941 .globl __kuser_helper_end
942 __kuser_helper_end:
944 #endif
946 THUMB( .thumb )
948 /*
949 * Vector stubs.
950 *
951 * This code is copied to 0xffff1000 so we can use branches in the
952 * vectors, rather than ldr's. Note that this code must not exceed
953 * a page size.
954 *
955 * Common stub entry macro:
956 * Enter in IRQ mode, spsr = SVC/USR CPSR, lr = SVC/USR PC
957 *
958 * SP points to a minimal amount of processor-private memory, the address
959 * of which is copied into r0 for the mode specific abort handler.
960 */
961 .macro vector_stub, name, mode, correction=0
962 .align 5
964 vector_\name:
965 .if \correction
966 sub lr, lr, #\correction
967 .endif
969 @
970 @ Save r0, lr_<exception> (parent PC) and spsr_<exception>
971 @ (parent CPSR)
972 @
973 stmia sp, {r0, lr} @ save r0, lr
974 mrs lr, spsr
975 str lr, [sp, #8] @ save spsr
977 @
978 @ Prepare for SVC32 mode. IRQs remain disabled.
979 @
980 mrs r0, cpsr
981 eor r0, r0, #(\mode ^ SVC_MODE | PSR_ISETSTATE)
982 msr spsr_cxsf, r0
984 @
985 @ the branch table must immediately follow this code
986 @
987 and lr, lr, #0x0f
988 THUMB( adr r0, 1f )
989 THUMB( ldr lr, [r0, lr, lsl #2] )
990 mov r0, sp
991 ARM( ldr lr, [pc, lr, lsl #2] )
992 movs pc, lr @ branch to handler in SVC mode
993 ENDPROC(vector_\name)
995 .align 2
996 @ handler addresses follow this label
997 1:
998 .endm
1000 .section .stubs, "ax", %progbits
1001 __stubs_start:
1002 @ This must be the first word
1003 .word vector_swi
1005 vector_rst:
1006 ARM( swi SYS_ERROR0 )
1007 THUMB( svc #0 )
1008 THUMB( nop )
1009 b vector_und
1011 /*
1012 * Interrupt dispatcher
1013 */
1014 vector_stub irq, IRQ_MODE, 4
1016 .long __irq_usr @ 0 (USR_26 / USR_32)
1017 .long __irq_invalid @ 1 (FIQ_26 / FIQ_32)
1018 .long __irq_invalid @ 2 (IRQ_26 / IRQ_32)
1019 .long __irq_svc @ 3 (SVC_26 / SVC_32)
1020 .long __irq_invalid @ 4
1021 .long __irq_invalid @ 5
1022 .long __irq_invalid @ 6
1023 .long __irq_invalid @ 7
1024 .long __irq_invalid @ 8
1025 .long __irq_invalid @ 9
1026 .long __irq_invalid @ a
1027 .long __irq_invalid @ b
1028 .long __irq_invalid @ c
1029 .long __irq_invalid @ d
1030 .long __irq_invalid @ e
1031 .long __irq_invalid @ f
1033 /*
1034 * Data abort dispatcher
1035 * Enter in ABT mode, spsr = USR CPSR, lr = USR PC
1036 */
1037 vector_stub dabt, ABT_MODE, 8
1039 .long __dabt_usr @ 0 (USR_26 / USR_32)
1040 .long __dabt_invalid @ 1 (FIQ_26 / FIQ_32)
1041 .long __dabt_invalid @ 2 (IRQ_26 / IRQ_32)
1042 .long __dabt_svc @ 3 (SVC_26 / SVC_32)
1043 .long __dabt_invalid @ 4
1044 .long __dabt_invalid @ 5
1045 .long __dabt_invalid @ 6
1046 .long __dabt_invalid @ 7
1047 .long __dabt_invalid @ 8
1048 .long __dabt_invalid @ 9
1049 .long __dabt_invalid @ a
1050 .long __dabt_invalid @ b
1051 .long __dabt_invalid @ c
1052 .long __dabt_invalid @ d
1053 .long __dabt_invalid @ e
1054 .long __dabt_invalid @ f
1056 /*
1057 * Prefetch abort dispatcher
1058 * Enter in ABT mode, spsr = USR CPSR, lr = USR PC
1059 */
1060 vector_stub pabt, ABT_MODE, 4
1062 .long __pabt_usr @ 0 (USR_26 / USR_32)
1063 .long __pabt_invalid @ 1 (FIQ_26 / FIQ_32)
1064 .long __pabt_invalid @ 2 (IRQ_26 / IRQ_32)
1065 .long __pabt_svc @ 3 (SVC_26 / SVC_32)
1066 .long __pabt_invalid @ 4
1067 .long __pabt_invalid @ 5
1068 .long __pabt_invalid @ 6
1069 .long __pabt_invalid @ 7
1070 .long __pabt_invalid @ 8
1071 .long __pabt_invalid @ 9
1072 .long __pabt_invalid @ a
1073 .long __pabt_invalid @ b
1074 .long __pabt_invalid @ c
1075 .long __pabt_invalid @ d
1076 .long __pabt_invalid @ e
1077 .long __pabt_invalid @ f
1079 /*
1080 * Undef instr entry dispatcher
1081 * Enter in UND mode, spsr = SVC/USR CPSR, lr = SVC/USR PC
1082 */
1083 vector_stub und, UND_MODE
1085 .long __und_usr @ 0 (USR_26 / USR_32)
1086 .long __und_invalid @ 1 (FIQ_26 / FIQ_32)
1087 .long __und_invalid @ 2 (IRQ_26 / IRQ_32)
1088 .long __und_svc @ 3 (SVC_26 / SVC_32)
1089 .long __und_invalid @ 4
1090 .long __und_invalid @ 5
1091 .long __und_invalid @ 6
1092 .long __und_invalid @ 7
1093 .long __und_invalid @ 8
1094 .long __und_invalid @ 9
1095 .long __und_invalid @ a
1096 .long __und_invalid @ b
1097 .long __und_invalid @ c
1098 .long __und_invalid @ d
1099 .long __und_invalid @ e
1100 .long __und_invalid @ f
1102 .align 5
1104 /*=============================================================================
1105 * Address exception handler
1106 *-----------------------------------------------------------------------------
1107 * These aren't too critical.
1108 * (they're not supposed to happen, and won't happen in 32-bit data mode).
1109 */
1111 vector_addrexcptn:
1112 b vector_addrexcptn
1114 /*=============================================================================
1115 * Undefined FIQs
1116 *-----------------------------------------------------------------------------
1117 * Enter in FIQ mode, spsr = ANY CPSR, lr = ANY PC
1118 * MUST PRESERVE SVC SPSR, but need to switch to SVC mode to show our msg.
1119 * Basically to switch modes, we *HAVE* to clobber one register... brain
1120 * damage alert! I don't think that we can execute any code in here in any
1121 * other mode than FIQ... Ok you can switch to another mode, but you can't
1122 * get out of that mode without clobbering one register.
1123 */
1124 vector_fiq:
1125 subs pc, lr, #4
1127 .globl vector_fiq_offset
1128 .equ vector_fiq_offset, vector_fiq
1130 .section .vectors, "ax", %progbits
1131 __vectors_start:
1132 W(b) vector_rst
1133 W(b) vector_und
1134 W(ldr) pc, __vectors_start + 0x1000
1135 W(b) vector_pabt
1136 W(b) vector_dabt
1137 W(b) vector_addrexcptn
1138 W(b) vector_irq
1139 W(b) vector_fiq
1141 .data
1143 .globl cr_alignment
1144 .globl cr_no_alignment
1145 cr_alignment:
1146 .space 4
1147 cr_no_alignment:
1148 .space 4
1150 #ifdef CONFIG_MULTI_IRQ_HANDLER
1151 .globl handle_arch_irq
1152 handle_arch_irq:
1153 .space 4
1154 #endif