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Merge tag 'nfsd-4.3' of git://linux-nfs.org/~bfields/linux
[mirror_ubuntu-zesty-kernel.git] / arch / arm / kernel / entry-armv.S
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 <linux/init.h>
19
20 #include <asm/assembler.h>
21 #include <asm/memory.h>
22 #include <asm/glue-df.h>
23 #include <asm/glue-pf.h>
24 #include <asm/vfpmacros.h>
25 #ifndef CONFIG_MULTI_IRQ_HANDLER
26 #include <mach/entry-macro.S>
27 #endif
28 #include <asm/thread_notify.h>
29 #include <asm/unwind.h>
30 #include <asm/unistd.h>
31 #include <asm/tls.h>
32 #include <asm/system_info.h>
33
34 #include "entry-header.S"
35 #include <asm/entry-macro-multi.S>
36 #include <asm/probes.h>
37
38 /*
39 * Interrupt handling.
40 */
41 .macro irq_handler
42 #ifdef CONFIG_MULTI_IRQ_HANDLER
43 ldr r1, =handle_arch_irq
44 mov r0, sp
45 badr lr, 9997f
46 ldr pc, [r1]
47 #else
48 arch_irq_handler_default
49 #endif
50 9997:
51 .endm
52
53 .macro pabt_helper
54 @ PABORT handler takes pt_regs in r2, fault address in r4 and psr in r5
55 #ifdef MULTI_PABORT
56 ldr ip, .LCprocfns
57 mov lr, pc
58 ldr pc, [ip, #PROCESSOR_PABT_FUNC]
59 #else
60 bl CPU_PABORT_HANDLER
61 #endif
62 .endm
63
64 .macro dabt_helper
65
66 @
67 @ Call the processor-specific abort handler:
68 @
69 @ r2 - pt_regs
70 @ r4 - aborted context pc
71 @ r5 - aborted context psr
72 @
73 @ The abort handler must return the aborted address in r0, and
74 @ the fault status register in r1. r9 must be preserved.
75 @
76 #ifdef MULTI_DABORT
77 ldr ip, .LCprocfns
78 mov lr, pc
79 ldr pc, [ip, #PROCESSOR_DABT_FUNC]
80 #else
81 bl CPU_DABORT_HANDLER
82 #endif
83 .endm
84
85 #ifdef CONFIG_KPROBES
86 .section .kprobes.text,"ax",%progbits
87 #else
88 .text
89 #endif
90
91 /*
92 * Invalid mode handlers
93 */
94 .macro inv_entry, reason
95 sub sp, sp, #S_FRAME_SIZE
96 ARM( stmib sp, {r1 - lr} )
97 THUMB( stmia sp, {r0 - r12} )
98 THUMB( str sp, [sp, #S_SP] )
99 THUMB( str lr, [sp, #S_LR] )
100 mov r1, #\reason
101 .endm
102
103 __pabt_invalid:
104 inv_entry BAD_PREFETCH
105 b common_invalid
106 ENDPROC(__pabt_invalid)
107
108 __dabt_invalid:
109 inv_entry BAD_DATA
110 b common_invalid
111 ENDPROC(__dabt_invalid)
112
113 __irq_invalid:
114 inv_entry BAD_IRQ
115 b common_invalid
116 ENDPROC(__irq_invalid)
117
118 __und_invalid:
119 inv_entry BAD_UNDEFINSTR
120
121 @
122 @ XXX fall through to common_invalid
123 @
124
125 @
126 @ common_invalid - generic code for failed exception (re-entrant version of handlers)
127 @
128 common_invalid:
129 zero_fp
130
131 ldmia r0, {r4 - r6}
132 add r0, sp, #S_PC @ here for interlock avoidance
133 mov r7, #-1 @ "" "" "" ""
134 str r4, [sp] @ save preserved r0
135 stmia r0, {r5 - r7} @ lr_<exception>,
136 @ cpsr_<exception>, "old_r0"
137
138 mov r0, sp
139 b bad_mode
140 ENDPROC(__und_invalid)
141
142 /*
143 * SVC mode handlers
144 */
145
146 #if defined(CONFIG_AEABI) && (__LINUX_ARM_ARCH__ >= 5)
147 #define SPFIX(code...) code
148 #else
149 #define SPFIX(code...)
150 #endif
151
152 .macro svc_entry, stack_hole=0, trace=1, uaccess=1
153 UNWIND(.fnstart )
154 UNWIND(.save {r0 - pc} )
155 sub sp, sp, #(S_FRAME_SIZE + 8 + \stack_hole - 4)
156 #ifdef CONFIG_THUMB2_KERNEL
157 SPFIX( str r0, [sp] ) @ temporarily saved
158 SPFIX( mov r0, sp )
159 SPFIX( tst r0, #4 ) @ test original stack alignment
160 SPFIX( ldr r0, [sp] ) @ restored
161 #else
162 SPFIX( tst sp, #4 )
163 #endif
164 SPFIX( subeq sp, sp, #4 )
165 stmia sp, {r1 - r12}
166
167 ldmia r0, {r3 - r5}
168 add r7, sp, #S_SP - 4 @ here for interlock avoidance
169 mov r6, #-1 @ "" "" "" ""
170 add r2, sp, #(S_FRAME_SIZE + 8 + \stack_hole - 4)
171 SPFIX( addeq r2, r2, #4 )
172 str r3, [sp, #-4]! @ save the "real" r0 copied
173 @ from the exception stack
174
175 mov r3, lr
176
177 @
178 @ We are now ready to fill in the remaining blanks on the stack:
179 @
180 @ r2 - sp_svc
181 @ r3 - lr_svc
182 @ r4 - lr_<exception>, already fixed up for correct return/restart
183 @ r5 - spsr_<exception>
184 @ r6 - orig_r0 (see pt_regs definition in ptrace.h)
185 @
186 stmia r7, {r2 - r6}
187
188 uaccess_save r0
189 .if \uaccess
190 uaccess_disable r0
191 .endif
192
193 .if \trace
194 #ifdef CONFIG_TRACE_IRQFLAGS
195 bl trace_hardirqs_off
196 #endif
197 .endif
198 .endm
199
200 .align 5
201 __dabt_svc:
202 svc_entry uaccess=0
203 mov r2, sp
204 dabt_helper
205 THUMB( ldr r5, [sp, #S_PSR] ) @ potentially updated CPSR
206 svc_exit r5 @ return from exception
207 UNWIND(.fnend )
208 ENDPROC(__dabt_svc)
209
210 .align 5
211 __irq_svc:
212 svc_entry
213 irq_handler
214
215 #ifdef CONFIG_PREEMPT
216 get_thread_info tsk
217 ldr r8, [tsk, #TI_PREEMPT] @ get preempt count
218 ldr r0, [tsk, #TI_FLAGS] @ get flags
219 teq r8, #0 @ if preempt count != 0
220 movne r0, #0 @ force flags to 0
221 tst r0, #_TIF_NEED_RESCHED
222 blne svc_preempt
223 #endif
224
225 svc_exit r5, irq = 1 @ return from exception
226 UNWIND(.fnend )
227 ENDPROC(__irq_svc)
228
229 .ltorg
230
231 #ifdef CONFIG_PREEMPT
232 svc_preempt:
233 mov r8, lr
234 1: bl preempt_schedule_irq @ irq en/disable is done inside
235 ldr r0, [tsk, #TI_FLAGS] @ get new tasks TI_FLAGS
236 tst r0, #_TIF_NEED_RESCHED
237 reteq r8 @ go again
238 b 1b
239 #endif
240
241 __und_fault:
242 @ Correct the PC such that it is pointing at the instruction
243 @ which caused the fault. If the faulting instruction was ARM
244 @ the PC will be pointing at the next instruction, and have to
245 @ subtract 4. Otherwise, it is Thumb, and the PC will be
246 @ pointing at the second half of the Thumb instruction. We
247 @ have to subtract 2.
248 ldr r2, [r0, #S_PC]
249 sub r2, r2, r1
250 str r2, [r0, #S_PC]
251 b do_undefinstr
252 ENDPROC(__und_fault)
253
254 .align 5
255 __und_svc:
256 #ifdef CONFIG_KPROBES
257 @ If a kprobe is about to simulate a "stmdb sp..." instruction,
258 @ it obviously needs free stack space which then will belong to
259 @ the saved context.
260 svc_entry MAX_STACK_SIZE
261 #else
262 svc_entry
263 #endif
264 @
265 @ call emulation code, which returns using r9 if it has emulated
266 @ the instruction, or the more conventional lr if we are to treat
267 @ this as a real undefined instruction
268 @
269 @ r0 - instruction
270 @
271 #ifndef CONFIG_THUMB2_KERNEL
272 ldr r0, [r4, #-4]
273 #else
274 mov r1, #2
275 ldrh r0, [r4, #-2] @ Thumb instruction at LR - 2
276 cmp r0, #0xe800 @ 32-bit instruction if xx >= 0
277 blo __und_svc_fault
278 ldrh r9, [r4] @ bottom 16 bits
279 add r4, r4, #2
280 str r4, [sp, #S_PC]
281 orr r0, r9, r0, lsl #16
282 #endif
283 badr r9, __und_svc_finish
284 mov r2, r4
285 bl call_fpe
286
287 mov r1, #4 @ PC correction to apply
288 __und_svc_fault:
289 mov r0, sp @ struct pt_regs *regs
290 bl __und_fault
291
292 __und_svc_finish:
293 ldr r5, [sp, #S_PSR] @ Get SVC cpsr
294 svc_exit r5 @ return from exception
295 UNWIND(.fnend )
296 ENDPROC(__und_svc)
297
298 .align 5
299 __pabt_svc:
300 svc_entry
301 mov r2, sp @ regs
302 pabt_helper
303 svc_exit r5 @ return from exception
304 UNWIND(.fnend )
305 ENDPROC(__pabt_svc)
306
307 .align 5
308 __fiq_svc:
309 svc_entry trace=0
310 mov r0, sp @ struct pt_regs *regs
311 bl handle_fiq_as_nmi
312 svc_exit_via_fiq
313 UNWIND(.fnend )
314 ENDPROC(__fiq_svc)
315
316 .align 5
317 .LCcralign:
318 .word cr_alignment
319 #ifdef MULTI_DABORT
320 .LCprocfns:
321 .word processor
322 #endif
323 .LCfp:
324 .word fp_enter
325
326 /*
327 * Abort mode handlers
328 */
329
330 @
331 @ Taking a FIQ in abort mode is similar to taking a FIQ in SVC mode
332 @ and reuses the same macros. However in abort mode we must also
333 @ save/restore lr_abt and spsr_abt to make nested aborts safe.
334 @
335 .align 5
336 __fiq_abt:
337 svc_entry trace=0
338
339 ARM( msr cpsr_c, #ABT_MODE | PSR_I_BIT | PSR_F_BIT )
340 THUMB( mov r0, #ABT_MODE | PSR_I_BIT | PSR_F_BIT )
341 THUMB( msr cpsr_c, r0 )
342 mov r1, lr @ Save lr_abt
343 mrs r2, spsr @ Save spsr_abt, abort is now safe
344 ARM( msr cpsr_c, #SVC_MODE | PSR_I_BIT | PSR_F_BIT )
345 THUMB( mov r0, #SVC_MODE | PSR_I_BIT | PSR_F_BIT )
346 THUMB( msr cpsr_c, r0 )
347 stmfd sp!, {r1 - r2}
348
349 add r0, sp, #8 @ struct pt_regs *regs
350 bl handle_fiq_as_nmi
351
352 ldmfd sp!, {r1 - r2}
353 ARM( msr cpsr_c, #ABT_MODE | PSR_I_BIT | PSR_F_BIT )
354 THUMB( mov r0, #ABT_MODE | PSR_I_BIT | PSR_F_BIT )
355 THUMB( msr cpsr_c, r0 )
356 mov lr, r1 @ Restore lr_abt, abort is unsafe
357 msr spsr_cxsf, r2 @ Restore spsr_abt
358 ARM( msr cpsr_c, #SVC_MODE | PSR_I_BIT | PSR_F_BIT )
359 THUMB( mov r0, #SVC_MODE | PSR_I_BIT | PSR_F_BIT )
360 THUMB( msr cpsr_c, r0 )
361
362 svc_exit_via_fiq
363 UNWIND(.fnend )
364 ENDPROC(__fiq_abt)
365
366 /*
367 * User mode handlers
368 *
369 * EABI note: sp_svc is always 64-bit aligned here, so should S_FRAME_SIZE
370 */
371
372 #if defined(CONFIG_AEABI) && (__LINUX_ARM_ARCH__ >= 5) && (S_FRAME_SIZE & 7)
373 #error "sizeof(struct pt_regs) must be a multiple of 8"
374 #endif
375
376 .macro usr_entry, trace=1, uaccess=1
377 UNWIND(.fnstart )
378 UNWIND(.cantunwind ) @ don't unwind the user space
379 sub sp, sp, #S_FRAME_SIZE
380 ARM( stmib sp, {r1 - r12} )
381 THUMB( stmia sp, {r0 - r12} )
382
383 ATRAP( mrc p15, 0, r7, c1, c0, 0)
384 ATRAP( ldr r8, .LCcralign)
385
386 ldmia r0, {r3 - r5}
387 add r0, sp, #S_PC @ here for interlock avoidance
388 mov r6, #-1 @ "" "" "" ""
389
390 str r3, [sp] @ save the "real" r0 copied
391 @ from the exception stack
392
393 ATRAP( ldr r8, [r8, #0])
394
395 @
396 @ We are now ready to fill in the remaining blanks on the stack:
397 @
398 @ r4 - lr_<exception>, already fixed up for correct return/restart
399 @ r5 - spsr_<exception>
400 @ r6 - orig_r0 (see pt_regs definition in ptrace.h)
401 @
402 @ Also, separately save sp_usr and lr_usr
403 @
404 stmia r0, {r4 - r6}
405 ARM( stmdb r0, {sp, lr}^ )
406 THUMB( store_user_sp_lr r0, r1, S_SP - S_PC )
407
408 .if \uaccess
409 uaccess_disable ip
410 .endif
411
412 @ Enable the alignment trap while in kernel mode
413 ATRAP( teq r8, r7)
414 ATRAP( mcrne p15, 0, r8, c1, c0, 0)
415
416 @
417 @ Clear FP to mark the first stack frame
418 @
419 zero_fp
420
421 .if \trace
422 #ifdef CONFIG_TRACE_IRQFLAGS
423 bl trace_hardirqs_off
424 #endif
425 ct_user_exit save = 0
426 .endif
427 .endm
428
429 .macro kuser_cmpxchg_check
430 #if !defined(CONFIG_CPU_32v6K) && defined(CONFIG_KUSER_HELPERS) && \
431 !defined(CONFIG_NEEDS_SYSCALL_FOR_CMPXCHG)
432 #ifndef CONFIG_MMU
433 #warning "NPTL on non MMU needs fixing"
434 #else
435 @ Make sure our user space atomic helper is restarted
436 @ if it was interrupted in a critical region. Here we
437 @ perform a quick test inline since it should be false
438 @ 99.9999% of the time. The rest is done out of line.
439 cmp r4, #TASK_SIZE
440 blhs kuser_cmpxchg64_fixup
441 #endif
442 #endif
443 .endm
444
445 .align 5
446 __dabt_usr:
447 usr_entry uaccess=0
448 kuser_cmpxchg_check
449 mov r2, sp
450 dabt_helper
451 b ret_from_exception
452 UNWIND(.fnend )
453 ENDPROC(__dabt_usr)
454
455 .align 5
456 __irq_usr:
457 usr_entry
458 kuser_cmpxchg_check
459 irq_handler
460 get_thread_info tsk
461 mov why, #0
462 b ret_to_user_from_irq
463 UNWIND(.fnend )
464 ENDPROC(__irq_usr)
465
466 .ltorg
467
468 .align 5
469 __und_usr:
470 usr_entry uaccess=0
471
472 mov r2, r4
473 mov r3, r5
474
475 @ r2 = regs->ARM_pc, which is either 2 or 4 bytes ahead of the
476 @ faulting instruction depending on Thumb mode.
477 @ r3 = regs->ARM_cpsr
478 @
479 @ The emulation code returns using r9 if it has emulated the
480 @ instruction, or the more conventional lr if we are to treat
481 @ this as a real undefined instruction
482 @
483 badr r9, ret_from_exception
484
485 @ IRQs must be enabled before attempting to read the instruction from
486 @ user space since that could cause a page/translation fault if the
487 @ page table was modified by another CPU.
488 enable_irq
489
490 tst r3, #PSR_T_BIT @ Thumb mode?
491 bne __und_usr_thumb
492 sub r4, r2, #4 @ ARM instr at LR - 4
493 1: ldrt r0, [r4]
494 ARM_BE8(rev r0, r0) @ little endian instruction
495
496 uaccess_disable ip
497
498 @ r0 = 32-bit ARM instruction which caused the exception
499 @ r2 = PC value for the following instruction (:= regs->ARM_pc)
500 @ r4 = PC value for the faulting instruction
501 @ lr = 32-bit undefined instruction function
502 badr lr, __und_usr_fault_32
503 b call_fpe
504
505 __und_usr_thumb:
506 @ Thumb instruction
507 sub r4, r2, #2 @ First half of thumb instr at LR - 2
508 #if CONFIG_ARM_THUMB && __LINUX_ARM_ARCH__ >= 6 && CONFIG_CPU_V7
509 /*
510 * Thumb-2 instruction handling. Note that because pre-v6 and >= v6 platforms
511 * can never be supported in a single kernel, this code is not applicable at
512 * all when __LINUX_ARM_ARCH__ < 6. This allows simplifying assumptions to be
513 * made about .arch directives.
514 */
515 #if __LINUX_ARM_ARCH__ < 7
516 /* If the target CPU may not be Thumb-2-capable, a run-time check is needed: */
517 #define NEED_CPU_ARCHITECTURE
518 ldr r5, .LCcpu_architecture
519 ldr r5, [r5]
520 cmp r5, #CPU_ARCH_ARMv7
521 blo __und_usr_fault_16 @ 16bit undefined instruction
522 /*
523 * The following code won't get run unless the running CPU really is v7, so
524 * coding round the lack of ldrht on older arches is pointless. Temporarily
525 * override the assembler target arch with the minimum required instead:
526 */
527 .arch armv6t2
528 #endif
529 2: ldrht r5, [r4]
530 ARM_BE8(rev16 r5, r5) @ little endian instruction
531 cmp r5, #0xe800 @ 32bit instruction if xx != 0
532 blo __und_usr_fault_16_pan @ 16bit undefined instruction
533 3: ldrht r0, [r2]
534 ARM_BE8(rev16 r0, r0) @ little endian instruction
535 uaccess_disable ip
536 add r2, r2, #2 @ r2 is PC + 2, make it PC + 4
537 str r2, [sp, #S_PC] @ it's a 2x16bit instr, update
538 orr r0, r0, r5, lsl #16
539 badr lr, __und_usr_fault_32
540 @ r0 = the two 16-bit Thumb instructions which caused the exception
541 @ r2 = PC value for the following Thumb instruction (:= regs->ARM_pc)
542 @ r4 = PC value for the first 16-bit Thumb instruction
543 @ lr = 32bit undefined instruction function
544
545 #if __LINUX_ARM_ARCH__ < 7
546 /* If the target arch was overridden, change it back: */
547 #ifdef CONFIG_CPU_32v6K
548 .arch armv6k
549 #else
550 .arch armv6
551 #endif
552 #endif /* __LINUX_ARM_ARCH__ < 7 */
553 #else /* !(CONFIG_ARM_THUMB && __LINUX_ARM_ARCH__ >= 6 && CONFIG_CPU_V7) */
554 b __und_usr_fault_16
555 #endif
556 UNWIND(.fnend)
557 ENDPROC(__und_usr)
558
559 /*
560 * The out of line fixup for the ldrt instructions above.
561 */
562 .pushsection .text.fixup, "ax"
563 .align 2
564 4: str r4, [sp, #S_PC] @ retry current instruction
565 ret r9
566 .popsection
567 .pushsection __ex_table,"a"
568 .long 1b, 4b
569 #if CONFIG_ARM_THUMB && __LINUX_ARM_ARCH__ >= 6 && CONFIG_CPU_V7
570 .long 2b, 4b
571 .long 3b, 4b
572 #endif
573 .popsection
574
575 /*
576 * Check whether the instruction is a co-processor instruction.
577 * If yes, we need to call the relevant co-processor handler.
578 *
579 * Note that we don't do a full check here for the co-processor
580 * instructions; all instructions with bit 27 set are well
581 * defined. The only instructions that should fault are the
582 * co-processor instructions. However, we have to watch out
583 * for the ARM6/ARM7 SWI bug.
584 *
585 * NEON is a special case that has to be handled here. Not all
586 * NEON instructions are co-processor instructions, so we have
587 * to make a special case of checking for them. Plus, there's
588 * five groups of them, so we have a table of mask/opcode pairs
589 * to check against, and if any match then we branch off into the
590 * NEON handler code.
591 *
592 * Emulators may wish to make use of the following registers:
593 * r0 = instruction opcode (32-bit ARM or two 16-bit Thumb)
594 * r2 = PC value to resume execution after successful emulation
595 * r9 = normal "successful" return address
596 * r10 = this threads thread_info structure
597 * lr = unrecognised instruction return address
598 * IRQs enabled, FIQs enabled.
599 */
600 @
601 @ Fall-through from Thumb-2 __und_usr
602 @
603 #ifdef CONFIG_NEON
604 get_thread_info r10 @ get current thread
605 adr r6, .LCneon_thumb_opcodes
606 b 2f
607 #endif
608 call_fpe:
609 get_thread_info r10 @ get current thread
610 #ifdef CONFIG_NEON
611 adr r6, .LCneon_arm_opcodes
612 2: ldr r5, [r6], #4 @ mask value
613 ldr r7, [r6], #4 @ opcode bits matching in mask
614 cmp r5, #0 @ end mask?
615 beq 1f
616 and r8, r0, r5
617 cmp r8, r7 @ NEON instruction?
618 bne 2b
619 mov r7, #1
620 strb r7, [r10, #TI_USED_CP + 10] @ mark CP#10 as used
621 strb r7, [r10, #TI_USED_CP + 11] @ mark CP#11 as used
622 b do_vfp @ let VFP handler handle this
623 1:
624 #endif
625 tst r0, #0x08000000 @ only CDP/CPRT/LDC/STC have bit 27
626 tstne r0, #0x04000000 @ bit 26 set on both ARM and Thumb-2
627 reteq lr
628 and r8, r0, #0x00000f00 @ mask out CP number
629 THUMB( lsr r8, r8, #8 )
630 mov r7, #1
631 add r6, r10, #TI_USED_CP
632 ARM( strb r7, [r6, r8, lsr #8] ) @ set appropriate used_cp[]
633 THUMB( strb r7, [r6, r8] ) @ set appropriate used_cp[]
634 #ifdef CONFIG_IWMMXT
635 @ Test if we need to give access to iWMMXt coprocessors
636 ldr r5, [r10, #TI_FLAGS]
637 rsbs r7, r8, #(1 << 8) @ CP 0 or 1 only
638 movcss r7, r5, lsr #(TIF_USING_IWMMXT + 1)
639 bcs iwmmxt_task_enable
640 #endif
641 ARM( add pc, pc, r8, lsr #6 )
642 THUMB( lsl r8, r8, #2 )
643 THUMB( add pc, r8 )
644 nop
645
646 ret.w lr @ CP#0
647 W(b) do_fpe @ CP#1 (FPE)
648 W(b) do_fpe @ CP#2 (FPE)
649 ret.w lr @ CP#3
650 #ifdef CONFIG_CRUNCH
651 b crunch_task_enable @ CP#4 (MaverickCrunch)
652 b crunch_task_enable @ CP#5 (MaverickCrunch)
653 b crunch_task_enable @ CP#6 (MaverickCrunch)
654 #else
655 ret.w lr @ CP#4
656 ret.w lr @ CP#5
657 ret.w lr @ CP#6
658 #endif
659 ret.w lr @ CP#7
660 ret.w lr @ CP#8
661 ret.w lr @ CP#9
662 #ifdef CONFIG_VFP
663 W(b) do_vfp @ CP#10 (VFP)
664 W(b) do_vfp @ CP#11 (VFP)
665 #else
666 ret.w lr @ CP#10 (VFP)
667 ret.w lr @ CP#11 (VFP)
668 #endif
669 ret.w lr @ CP#12
670 ret.w lr @ CP#13
671 ret.w lr @ CP#14 (Debug)
672 ret.w lr @ CP#15 (Control)
673
674 #ifdef NEED_CPU_ARCHITECTURE
675 .align 2
676 .LCcpu_architecture:
677 .word __cpu_architecture
678 #endif
679
680 #ifdef CONFIG_NEON
681 .align 6
682
683 .LCneon_arm_opcodes:
684 .word 0xfe000000 @ mask
685 .word 0xf2000000 @ opcode
686
687 .word 0xff100000 @ mask
688 .word 0xf4000000 @ opcode
689
690 .word 0x00000000 @ mask
691 .word 0x00000000 @ opcode
692
693 .LCneon_thumb_opcodes:
694 .word 0xef000000 @ mask
695 .word 0xef000000 @ opcode
696
697 .word 0xff100000 @ mask
698 .word 0xf9000000 @ opcode
699
700 .word 0x00000000 @ mask
701 .word 0x00000000 @ opcode
702 #endif
703
704 do_fpe:
705 ldr r4, .LCfp
706 add r10, r10, #TI_FPSTATE @ r10 = workspace
707 ldr pc, [r4] @ Call FP module USR entry point
708
709 /*
710 * The FP module is called with these registers set:
711 * r0 = instruction
712 * r2 = PC+4
713 * r9 = normal "successful" return address
714 * r10 = FP workspace
715 * lr = unrecognised FP instruction return address
716 */
717
718 .pushsection .data
719 ENTRY(fp_enter)
720 .word no_fp
721 .popsection
722
723 ENTRY(no_fp)
724 ret lr
725 ENDPROC(no_fp)
726
727 __und_usr_fault_32:
728 mov r1, #4
729 b 1f
730 __und_usr_fault_16_pan:
731 uaccess_disable ip
732 __und_usr_fault_16:
733 mov r1, #2
734 1: mov r0, sp
735 badr lr, ret_from_exception
736 b __und_fault
737 ENDPROC(__und_usr_fault_32)
738 ENDPROC(__und_usr_fault_16)
739
740 .align 5
741 __pabt_usr:
742 usr_entry
743 mov r2, sp @ regs
744 pabt_helper
745 UNWIND(.fnend )
746 /* fall through */
747 /*
748 * This is the return code to user mode for abort handlers
749 */
750 ENTRY(ret_from_exception)
751 UNWIND(.fnstart )
752 UNWIND(.cantunwind )
753 get_thread_info tsk
754 mov why, #0
755 b ret_to_user
756 UNWIND(.fnend )
757 ENDPROC(__pabt_usr)
758 ENDPROC(ret_from_exception)
759
760 .align 5
761 __fiq_usr:
762 usr_entry trace=0
763 kuser_cmpxchg_check
764 mov r0, sp @ struct pt_regs *regs
765 bl handle_fiq_as_nmi
766 get_thread_info tsk
767 restore_user_regs fast = 0, offset = 0
768 UNWIND(.fnend )
769 ENDPROC(__fiq_usr)
770
771 /*
772 * Register switch for ARMv3 and ARMv4 processors
773 * r0 = previous task_struct, r1 = previous thread_info, r2 = next thread_info
774 * previous and next are guaranteed not to be the same.
775 */
776 ENTRY(__switch_to)
777 UNWIND(.fnstart )
778 UNWIND(.cantunwind )
779 add ip, r1, #TI_CPU_SAVE
780 ARM( stmia ip!, {r4 - sl, fp, sp, lr} ) @ Store most regs on stack
781 THUMB( stmia ip!, {r4 - sl, fp} ) @ Store most regs on stack
782 THUMB( str sp, [ip], #4 )
783 THUMB( str lr, [ip], #4 )
784 ldr r4, [r2, #TI_TP_VALUE]
785 ldr r5, [r2, #TI_TP_VALUE + 4]
786 #ifdef CONFIG_CPU_USE_DOMAINS
787 mrc p15, 0, r6, c3, c0, 0 @ Get domain register
788 str r6, [r1, #TI_CPU_DOMAIN] @ Save old domain register
789 ldr r6, [r2, #TI_CPU_DOMAIN]
790 #endif
791 switch_tls r1, r4, r5, r3, r7
792 #if defined(CONFIG_CC_STACKPROTECTOR) && !defined(CONFIG_SMP)
793 ldr r7, [r2, #TI_TASK]
794 ldr r8, =__stack_chk_guard
795 ldr r7, [r7, #TSK_STACK_CANARY]
796 #endif
797 #ifdef CONFIG_CPU_USE_DOMAINS
798 mcr p15, 0, r6, c3, c0, 0 @ Set domain register
799 #endif
800 mov r5, r0
801 add r4, r2, #TI_CPU_SAVE
802 ldr r0, =thread_notify_head
803 mov r1, #THREAD_NOTIFY_SWITCH
804 bl atomic_notifier_call_chain
805 #if defined(CONFIG_CC_STACKPROTECTOR) && !defined(CONFIG_SMP)
806 str r7, [r8]
807 #endif
808 THUMB( mov ip, r4 )
809 mov r0, r5
810 ARM( ldmia r4, {r4 - sl, fp, sp, pc} ) @ Load all regs saved previously
811 THUMB( ldmia ip!, {r4 - sl, fp} ) @ Load all regs saved previously
812 THUMB( ldr sp, [ip], #4 )
813 THUMB( ldr pc, [ip] )
814 UNWIND(.fnend )
815 ENDPROC(__switch_to)
816
817 __INIT
818
819 /*
820 * User helpers.
821 *
822 * Each segment is 32-byte aligned and will be moved to the top of the high
823 * vector page. New segments (if ever needed) must be added in front of
824 * existing ones. This mechanism should be used only for things that are
825 * really small and justified, and not be abused freely.
826 *
827 * See Documentation/arm/kernel_user_helpers.txt for formal definitions.
828 */
829 THUMB( .arm )
830
831 .macro usr_ret, reg
832 #ifdef CONFIG_ARM_THUMB
833 bx \reg
834 #else
835 ret \reg
836 #endif
837 .endm
838
839 .macro kuser_pad, sym, size
840 .if (. - \sym) & 3
841 .rept 4 - (. - \sym) & 3
842 .byte 0
843 .endr
844 .endif
845 .rept (\size - (. - \sym)) / 4
846 .word 0xe7fddef1
847 .endr
848 .endm
849
850 #ifdef CONFIG_KUSER_HELPERS
851 .align 5
852 .globl __kuser_helper_start
853 __kuser_helper_start:
854
855 /*
856 * Due to the length of some sequences, __kuser_cmpxchg64 spans 2 regular
857 * kuser "slots", therefore 0xffff0f80 is not used as a valid entry point.
858 */
859
860 __kuser_cmpxchg64: @ 0xffff0f60
861
862 #if defined(CONFIG_NEEDS_SYSCALL_FOR_CMPXCHG)
863
864 /*
865 * Poor you. No fast solution possible...
866 * The kernel itself must perform the operation.
867 * A special ghost syscall is used for that (see traps.c).
868 */
869 stmfd sp!, {r7, lr}
870 ldr r7, 1f @ it's 20 bits
871 swi __ARM_NR_cmpxchg64
872 ldmfd sp!, {r7, pc}
873 1: .word __ARM_NR_cmpxchg64
874
875 #elif defined(CONFIG_CPU_32v6K)
876
877 stmfd sp!, {r4, r5, r6, r7}
878 ldrd r4, r5, [r0] @ load old val
879 ldrd r6, r7, [r1] @ load new val
880 smp_dmb arm
881 1: ldrexd r0, r1, [r2] @ load current val
882 eors r3, r0, r4 @ compare with oldval (1)
883 eoreqs r3, r1, r5 @ compare with oldval (2)
884 strexdeq r3, r6, r7, [r2] @ store newval if eq
885 teqeq r3, #1 @ success?
886 beq 1b @ if no then retry
887 smp_dmb arm
888 rsbs r0, r3, #0 @ set returned val and C flag
889 ldmfd sp!, {r4, r5, r6, r7}
890 usr_ret lr
891
892 #elif !defined(CONFIG_SMP)
893
894 #ifdef CONFIG_MMU
895
896 /*
897 * The only thing that can break atomicity in this cmpxchg64
898 * implementation is either an IRQ or a data abort exception
899 * causing another process/thread to be scheduled in the middle of
900 * the critical sequence. The same strategy as for cmpxchg is used.
901 */
902 stmfd sp!, {r4, r5, r6, lr}
903 ldmia r0, {r4, r5} @ load old val
904 ldmia r1, {r6, lr} @ load new val
905 1: ldmia r2, {r0, r1} @ load current val
906 eors r3, r0, r4 @ compare with oldval (1)
907 eoreqs r3, r1, r5 @ compare with oldval (2)
908 2: stmeqia r2, {r6, lr} @ store newval if eq
909 rsbs r0, r3, #0 @ set return val and C flag
910 ldmfd sp!, {r4, r5, r6, pc}
911
912 .text
913 kuser_cmpxchg64_fixup:
914 @ Called from kuser_cmpxchg_fixup.
915 @ r4 = address of interrupted insn (must be preserved).
916 @ sp = saved regs. r7 and r8 are clobbered.
917 @ 1b = first critical insn, 2b = last critical insn.
918 @ If r4 >= 1b and r4 <= 2b then saved pc_usr is set to 1b.
919 mov r7, #0xffff0fff
920 sub r7, r7, #(0xffff0fff - (0xffff0f60 + (1b - __kuser_cmpxchg64)))
921 subs r8, r4, r7
922 rsbcss r8, r8, #(2b - 1b)
923 strcs r7, [sp, #S_PC]
924 #if __LINUX_ARM_ARCH__ < 6
925 bcc kuser_cmpxchg32_fixup
926 #endif
927 ret lr
928 .previous
929
930 #else
931 #warning "NPTL on non MMU needs fixing"
932 mov r0, #-1
933 adds r0, r0, #0
934 usr_ret lr
935 #endif
936
937 #else
938 #error "incoherent kernel configuration"
939 #endif
940
941 kuser_pad __kuser_cmpxchg64, 64
942
943 __kuser_memory_barrier: @ 0xffff0fa0
944 smp_dmb arm
945 usr_ret lr
946
947 kuser_pad __kuser_memory_barrier, 32
948
949 __kuser_cmpxchg: @ 0xffff0fc0
950
951 #if defined(CONFIG_NEEDS_SYSCALL_FOR_CMPXCHG)
952
953 /*
954 * Poor you. No fast solution possible...
955 * The kernel itself must perform the operation.
956 * A special ghost syscall is used for that (see traps.c).
957 */
958 stmfd sp!, {r7, lr}
959 ldr r7, 1f @ it's 20 bits
960 swi __ARM_NR_cmpxchg
961 ldmfd sp!, {r7, pc}
962 1: .word __ARM_NR_cmpxchg
963
964 #elif __LINUX_ARM_ARCH__ < 6
965
966 #ifdef CONFIG_MMU
967
968 /*
969 * The only thing that can break atomicity in this cmpxchg
970 * implementation is either an IRQ or a data abort exception
971 * causing another process/thread to be scheduled in the middle
972 * of the critical sequence. To prevent this, code is added to
973 * the IRQ and data abort exception handlers to set the pc back
974 * to the beginning of the critical section if it is found to be
975 * within that critical section (see kuser_cmpxchg_fixup).
976 */
977 1: ldr r3, [r2] @ load current val
978 subs r3, r3, r0 @ compare with oldval
979 2: streq r1, [r2] @ store newval if eq
980 rsbs r0, r3, #0 @ set return val and C flag
981 usr_ret lr
982
983 .text
984 kuser_cmpxchg32_fixup:
985 @ Called from kuser_cmpxchg_check macro.
986 @ r4 = address of interrupted insn (must be preserved).
987 @ sp = saved regs. r7 and r8 are clobbered.
988 @ 1b = first critical insn, 2b = last critical insn.
989 @ If r4 >= 1b and r4 <= 2b then saved pc_usr is set to 1b.
990 mov r7, #0xffff0fff
991 sub r7, r7, #(0xffff0fff - (0xffff0fc0 + (1b - __kuser_cmpxchg)))
992 subs r8, r4, r7
993 rsbcss r8, r8, #(2b - 1b)
994 strcs r7, [sp, #S_PC]
995 ret lr
996 .previous
997
998 #else
999 #warning "NPTL on non MMU needs fixing"
1000 mov r0, #-1
1001 adds r0, r0, #0
1002 usr_ret lr
1003 #endif
1004
1005 #else
1006
1007 smp_dmb arm
1008 1: ldrex r3, [r2]
1009 subs r3, r3, r0
1010 strexeq r3, r1, [r2]
1011 teqeq r3, #1
1012 beq 1b
1013 rsbs r0, r3, #0
1014 /* beware -- each __kuser slot must be 8 instructions max */
1015 ALT_SMP(b __kuser_memory_barrier)
1016 ALT_UP(usr_ret lr)
1017
1018 #endif
1019
1020 kuser_pad __kuser_cmpxchg, 32
1021
1022 __kuser_get_tls: @ 0xffff0fe0
1023 ldr r0, [pc, #(16 - 8)] @ read TLS, set in kuser_get_tls_init
1024 usr_ret lr
1025 mrc p15, 0, r0, c13, c0, 3 @ 0xffff0fe8 hardware TLS code
1026 kuser_pad __kuser_get_tls, 16
1027 .rep 3
1028 .word 0 @ 0xffff0ff0 software TLS value, then
1029 .endr @ pad up to __kuser_helper_version
1030
1031 __kuser_helper_version: @ 0xffff0ffc
1032 .word ((__kuser_helper_end - __kuser_helper_start) >> 5)
1033
1034 .globl __kuser_helper_end
1035 __kuser_helper_end:
1036
1037 #endif
1038
1039 THUMB( .thumb )
1040
1041 /*
1042 * Vector stubs.
1043 *
1044 * This code is copied to 0xffff1000 so we can use branches in the
1045 * vectors, rather than ldr's. Note that this code must not exceed
1046 * a page size.
1047 *
1048 * Common stub entry macro:
1049 * Enter in IRQ mode, spsr = SVC/USR CPSR, lr = SVC/USR PC
1050 *
1051 * SP points to a minimal amount of processor-private memory, the address
1052 * of which is copied into r0 for the mode specific abort handler.
1053 */
1054 .macro vector_stub, name, mode, correction=0
1055 .align 5
1056
1057 vector_\name:
1058 .if \correction
1059 sub lr, lr, #\correction
1060 .endif
1061
1062 @
1063 @ Save r0, lr_<exception> (parent PC) and spsr_<exception>
1064 @ (parent CPSR)
1065 @
1066 stmia sp, {r0, lr} @ save r0, lr
1067 mrs lr, spsr
1068 str lr, [sp, #8] @ save spsr
1069
1070 @
1071 @ Prepare for SVC32 mode. IRQs remain disabled.
1072 @
1073 mrs r0, cpsr
1074 eor r0, r0, #(\mode ^ SVC_MODE | PSR_ISETSTATE)
1075 msr spsr_cxsf, r0
1076
1077 @
1078 @ the branch table must immediately follow this code
1079 @
1080 and lr, lr, #0x0f
1081 THUMB( adr r0, 1f )
1082 THUMB( ldr lr, [r0, lr, lsl #2] )
1083 mov r0, sp
1084 ARM( ldr lr, [pc, lr, lsl #2] )
1085 movs pc, lr @ branch to handler in SVC mode
1086 ENDPROC(vector_\name)
1087
1088 .align 2
1089 @ handler addresses follow this label
1090 1:
1091 .endm
1092
1093 .section .stubs, "ax", %progbits
1094 __stubs_start:
1095 @ This must be the first word
1096 .word vector_swi
1097
1098 vector_rst:
1099 ARM( swi SYS_ERROR0 )
1100 THUMB( svc #0 )
1101 THUMB( nop )
1102 b vector_und
1103
1104 /*
1105 * Interrupt dispatcher
1106 */
1107 vector_stub irq, IRQ_MODE, 4
1108
1109 .long __irq_usr @ 0 (USR_26 / USR_32)
1110 .long __irq_invalid @ 1 (FIQ_26 / FIQ_32)
1111 .long __irq_invalid @ 2 (IRQ_26 / IRQ_32)
1112 .long __irq_svc @ 3 (SVC_26 / SVC_32)
1113 .long __irq_invalid @ 4
1114 .long __irq_invalid @ 5
1115 .long __irq_invalid @ 6
1116 .long __irq_invalid @ 7
1117 .long __irq_invalid @ 8
1118 .long __irq_invalid @ 9
1119 .long __irq_invalid @ a
1120 .long __irq_invalid @ b
1121 .long __irq_invalid @ c
1122 .long __irq_invalid @ d
1123 .long __irq_invalid @ e
1124 .long __irq_invalid @ f
1125
1126 /*
1127 * Data abort dispatcher
1128 * Enter in ABT mode, spsr = USR CPSR, lr = USR PC
1129 */
1130 vector_stub dabt, ABT_MODE, 8
1131
1132 .long __dabt_usr @ 0 (USR_26 / USR_32)
1133 .long __dabt_invalid @ 1 (FIQ_26 / FIQ_32)
1134 .long __dabt_invalid @ 2 (IRQ_26 / IRQ_32)
1135 .long __dabt_svc @ 3 (SVC_26 / SVC_32)
1136 .long __dabt_invalid @ 4
1137 .long __dabt_invalid @ 5
1138 .long __dabt_invalid @ 6
1139 .long __dabt_invalid @ 7
1140 .long __dabt_invalid @ 8
1141 .long __dabt_invalid @ 9
1142 .long __dabt_invalid @ a
1143 .long __dabt_invalid @ b
1144 .long __dabt_invalid @ c
1145 .long __dabt_invalid @ d
1146 .long __dabt_invalid @ e
1147 .long __dabt_invalid @ f
1148
1149 /*
1150 * Prefetch abort dispatcher
1151 * Enter in ABT mode, spsr = USR CPSR, lr = USR PC
1152 */
1153 vector_stub pabt, ABT_MODE, 4
1154
1155 .long __pabt_usr @ 0 (USR_26 / USR_32)
1156 .long __pabt_invalid @ 1 (FIQ_26 / FIQ_32)
1157 .long __pabt_invalid @ 2 (IRQ_26 / IRQ_32)
1158 .long __pabt_svc @ 3 (SVC_26 / SVC_32)
1159 .long __pabt_invalid @ 4
1160 .long __pabt_invalid @ 5
1161 .long __pabt_invalid @ 6
1162 .long __pabt_invalid @ 7
1163 .long __pabt_invalid @ 8
1164 .long __pabt_invalid @ 9
1165 .long __pabt_invalid @ a
1166 .long __pabt_invalid @ b
1167 .long __pabt_invalid @ c
1168 .long __pabt_invalid @ d
1169 .long __pabt_invalid @ e
1170 .long __pabt_invalid @ f
1171
1172 /*
1173 * Undef instr entry dispatcher
1174 * Enter in UND mode, spsr = SVC/USR CPSR, lr = SVC/USR PC
1175 */
1176 vector_stub und, UND_MODE
1177
1178 .long __und_usr @ 0 (USR_26 / USR_32)
1179 .long __und_invalid @ 1 (FIQ_26 / FIQ_32)
1180 .long __und_invalid @ 2 (IRQ_26 / IRQ_32)
1181 .long __und_svc @ 3 (SVC_26 / SVC_32)
1182 .long __und_invalid @ 4
1183 .long __und_invalid @ 5
1184 .long __und_invalid @ 6
1185 .long __und_invalid @ 7
1186 .long __und_invalid @ 8
1187 .long __und_invalid @ 9
1188 .long __und_invalid @ a
1189 .long __und_invalid @ b
1190 .long __und_invalid @ c
1191 .long __und_invalid @ d
1192 .long __und_invalid @ e
1193 .long __und_invalid @ f
1194
1195 .align 5
1196
1197 /*=============================================================================
1198 * Address exception handler
1199 *-----------------------------------------------------------------------------
1200 * These aren't too critical.
1201 * (they're not supposed to happen, and won't happen in 32-bit data mode).
1202 */
1203
1204 vector_addrexcptn:
1205 b vector_addrexcptn
1206
1207 /*=============================================================================
1208 * FIQ "NMI" handler
1209 *-----------------------------------------------------------------------------
1210 * Handle a FIQ using the SVC stack allowing FIQ act like NMI on x86
1211 * systems.
1212 */
1213 vector_stub fiq, FIQ_MODE, 4
1214
1215 .long __fiq_usr @ 0 (USR_26 / USR_32)
1216 .long __fiq_svc @ 1 (FIQ_26 / FIQ_32)
1217 .long __fiq_svc @ 2 (IRQ_26 / IRQ_32)
1218 .long __fiq_svc @ 3 (SVC_26 / SVC_32)
1219 .long __fiq_svc @ 4
1220 .long __fiq_svc @ 5
1221 .long __fiq_svc @ 6
1222 .long __fiq_abt @ 7
1223 .long __fiq_svc @ 8
1224 .long __fiq_svc @ 9
1225 .long __fiq_svc @ a
1226 .long __fiq_svc @ b
1227 .long __fiq_svc @ c
1228 .long __fiq_svc @ d
1229 .long __fiq_svc @ e
1230 .long __fiq_svc @ f
1231
1232 .globl vector_fiq_offset
1233 .equ vector_fiq_offset, vector_fiq
1234
1235 .section .vectors, "ax", %progbits
1236 __vectors_start:
1237 W(b) vector_rst
1238 W(b) vector_und
1239 W(ldr) pc, __vectors_start + 0x1000
1240 W(b) vector_pabt
1241 W(b) vector_dabt
1242 W(b) vector_addrexcptn
1243 W(b) vector_irq
1244 W(b) vector_fiq
1245
1246 .data
1247
1248 .globl cr_alignment
1249 cr_alignment:
1250 .space 4
1251
1252 #ifdef CONFIG_MULTI_IRQ_HANDLER
1253 .globl handle_arch_irq
1254 handle_arch_irq:
1255 .space 4
1256 #endif
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