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1/*
2 * linux/arch/arm/kernel/entry-armv.S
3 *
4 * Copyright (C) 1996,1997,1998 Russell King.
5 * ARM700 fix by Matthew Godbolt (linux-user@willothewisp.demon.co.uk)
6 * nommu support by Hyok S. Choi (hyok.choi@samsung.com)
7 *
8 * This program is free software; you can redistribute it and/or modify
9 * it under the terms of the GNU General Public License version 2 as
10 * published by the Free Software Foundation.
11 *
12 * Low-level vector interface routines
13 *
14 * Note: there is a StrongARM bug in the STMIA rn, {regs}^ instruction
15 * that causes it to save wrong values... Be aware!
16 */
17
18#include <asm/assembler.h>
19#include <asm/memory.h>
20#include <asm/glue-df.h>
21#include <asm/glue-pf.h>
22#include <asm/vfpmacros.h>
23#ifndef CONFIG_MULTI_IRQ_HANDLER
24#include <mach/entry-macro.S>
25#endif
26#include <asm/thread_notify.h>
27#include <asm/unwind.h>
28#include <asm/unistd.h>
29#include <asm/tls.h>
30#include <asm/system_info.h>
31
32#include "entry-header.S"
33#include <asm/entry-macro-multi.S>
34
35/*
36 * Interrupt handling.
37 */
38 .macro irq_handler
39#ifdef CONFIG_MULTI_IRQ_HANDLER
40 ldr r1, =handle_arch_irq
41 mov r0, sp
42 adr lr, BSYM(9997f)
43 ldr pc, [r1]
44#else
45 arch_irq_handler_default
46#endif
479997:
48 .endm
49
50 .macro pabt_helper
51 @ PABORT handler takes pt_regs in r2, fault address in r4 and psr in r5
52#ifdef MULTI_PABORT
53 ldr ip, .LCprocfns
54 mov lr, pc
55 ldr pc, [ip, #PROCESSOR_PABT_FUNC]
56#else
57 bl CPU_PABORT_HANDLER
58#endif
59 .endm
60
61 .macro dabt_helper
62
63 @
64 @ Call the processor-specific abort handler:
65 @
66 @ r2 - pt_regs
67 @ r4 - aborted context pc
68 @ r5 - aborted context psr
69 @
70 @ The abort handler must return the aborted address in r0, and
71 @ the fault status register in r1. r9 must be preserved.
72 @
73#ifdef MULTI_DABORT
74 ldr ip, .LCprocfns
75 mov lr, pc
76 ldr pc, [ip, #PROCESSOR_DABT_FUNC]
77#else
78 bl CPU_DABORT_HANDLER
79#endif
80 .endm
81
82#ifdef CONFIG_KPROBES
83 .section .kprobes.text,"ax",%progbits
84#else
85 .text
86#endif
87
88/*
89 * Invalid mode handlers
90 */
91 .macro inv_entry, reason
92 sub sp, sp, #S_FRAME_SIZE
93 ARM( stmib sp, {r1 - lr} )
94 THUMB( stmia sp, {r0 - r12} )
95 THUMB( str sp, [sp, #S_SP] )
96 THUMB( str lr, [sp, #S_LR] )
97 mov r1, #\reason
98 .endm
99
100__pabt_invalid:
101 inv_entry BAD_PREFETCH
102 b common_invalid
103ENDPROC(__pabt_invalid)
104
105__dabt_invalid:
106 inv_entry BAD_DATA
107 b common_invalid
108ENDPROC(__dabt_invalid)
109
110__irq_invalid:
111 inv_entry BAD_IRQ
112 b common_invalid
113ENDPROC(__irq_invalid)
114
115__und_invalid:
116 inv_entry BAD_UNDEFINSTR
117
118 @
119 @ XXX fall through to common_invalid
120 @
121
122@
123@ common_invalid - generic code for failed exception (re-entrant version of handlers)
124@
125common_invalid:
126 zero_fp
127
128 ldmia r0, {r4 - r6}
129 add r0, sp, #S_PC @ here for interlock avoidance
130 mov r7, #-1 @ "" "" "" ""
131 str r4, [sp] @ save preserved r0
132 stmia r0, {r5 - r7} @ lr_<exception>,
133 @ cpsr_<exception>, "old_r0"
134
135 mov r0, sp
136 b bad_mode
137ENDPROC(__und_invalid)
138
139/*
140 * SVC mode handlers
141 */
142
143#if defined(CONFIG_AEABI) && (__LINUX_ARM_ARCH__ >= 5)
144#define SPFIX(code...) code
145#else
146#define SPFIX(code...)
147#endif
148
149 .macro svc_entry, stack_hole=0
150 UNWIND(.fnstart )
151 UNWIND(.save {r0 - pc} )
152 sub sp, sp, #(S_FRAME_SIZE + \stack_hole - 4)
153#ifdef CONFIG_THUMB2_KERNEL
154 SPFIX( str r0, [sp] ) @ temporarily saved
155 SPFIX( mov r0, sp )
156 SPFIX( tst r0, #4 ) @ test original stack alignment
157 SPFIX( ldr r0, [sp] ) @ restored
158#else
159 SPFIX( tst sp, #4 )
160#endif
161 SPFIX( subeq sp, sp, #4 )
162 stmia sp, {r1 - r12}
163
164 ldmia r0, {r3 - r5}
165 add r7, sp, #S_SP - 4 @ here for interlock avoidance
166 mov r6, #-1 @ "" "" "" ""
167 add r2, sp, #(S_FRAME_SIZE + \stack_hole - 4)
168 SPFIX( addeq r2, r2, #4 )
169 str r3, [sp, #-4]! @ save the "real" r0 copied
170 @ from the exception stack
171
172 mov r3, lr
173
174 @
175 @ We are now ready to fill in the remaining blanks on the stack:
176 @
177 @ r2 - sp_svc
178 @ r3 - lr_svc
179 @ r4 - lr_<exception>, already fixed up for correct return/restart
180 @ r5 - spsr_<exception>
181 @ r6 - orig_r0 (see pt_regs definition in ptrace.h)
182 @
183 stmia r7, {r2 - r6}
184
185#ifdef CONFIG_TRACE_IRQFLAGS
186 bl trace_hardirqs_off
187#endif
188 .endm
189
190 .align 5
191__dabt_svc:
192 svc_entry
193 mov r2, sp
194 dabt_helper
195 THUMB( ldr r5, [sp, #S_PSR] ) @ potentially updated CPSR
196 svc_exit r5 @ return from exception
197 UNWIND(.fnend )
198ENDPROC(__dabt_svc)
199
200 .align 5
201__irq_svc:
202 svc_entry
203 irq_handler
204
205#ifdef CONFIG_PREEMPT
206 get_thread_info tsk
207 ldr r8, [tsk, #TI_PREEMPT] @ get preempt count
208 ldr r0, [tsk, #TI_FLAGS] @ get flags
209 teq r8, #0 @ if preempt count != 0
210 movne r0, #0 @ force flags to 0
211 tst r0, #_TIF_NEED_RESCHED
212 blne svc_preempt
213#endif
214
215 svc_exit r5, irq = 1 @ return from exception
216 UNWIND(.fnend )
217ENDPROC(__irq_svc)
218
219 .ltorg
220
221#ifdef CONFIG_PREEMPT
222svc_preempt:
223 mov r8, lr
2241: bl preempt_schedule_irq @ irq en/disable is done inside
225 ldr r0, [tsk, #TI_FLAGS] @ get new tasks TI_FLAGS
226 tst r0, #_TIF_NEED_RESCHED
227 moveq pc, r8 @ go again
228 b 1b
229#endif
230
231__und_fault:
232 @ Correct the PC such that it is pointing at the instruction
233 @ which caused the fault. If the faulting instruction was ARM
234 @ the PC will be pointing at the next instruction, and have to
235 @ subtract 4. Otherwise, it is Thumb, and the PC will be
236 @ pointing at the second half of the Thumb instruction. We
237 @ have to subtract 2.
238 ldr r2, [r0, #S_PC]
239 sub r2, r2, r1
240 str r2, [r0, #S_PC]
241 b do_undefinstr
242ENDPROC(__und_fault)
243
244 .align 5
245__und_svc:
246#ifdef CONFIG_KPROBES
247 @ If a kprobe is about to simulate a "stmdb sp..." instruction,
248 @ it obviously needs free stack space which then will belong to
249 @ the saved context.
250 svc_entry 64
251#else
252 svc_entry
253#endif
254 @
255 @ call emulation code, which returns using r9 if it has emulated
256 @ the instruction, or the more conventional lr if we are to treat
257 @ this as a real undefined instruction
258 @
259 @ r0 - instruction
260 @
261#ifndef CONFIG_THUMB2_KERNEL
262 ldr r0, [r4, #-4]
263#else
264 mov r1, #2
265 ldrh r0, [r4, #-2] @ Thumb instruction at LR - 2
266 cmp r0, #0xe800 @ 32-bit instruction if xx >= 0
267 blo __und_svc_fault
268 ldrh r9, [r4] @ bottom 16 bits
269 add r4, r4, #2
270 str r4, [sp, #S_PC]
271 orr r0, r9, r0, lsl #16
272#endif
273 adr r9, BSYM(__und_svc_finish)
274 mov r2, r4
275 bl call_fpe
276
277 mov r1, #4 @ PC correction to apply
278__und_svc_fault:
279 mov r0, sp @ struct pt_regs *regs
280 bl __und_fault
281
282__und_svc_finish:
283 ldr r5, [sp, #S_PSR] @ Get SVC cpsr
284 svc_exit r5 @ return from exception
285 UNWIND(.fnend )
286ENDPROC(__und_svc)
287
288 .align 5
289__pabt_svc:
290 svc_entry
291 mov r2, sp @ regs
292 pabt_helper
293 svc_exit r5 @ return from exception
294 UNWIND(.fnend )
295ENDPROC(__pabt_svc)
296
297 .align 5
298.LCcralign:
299 .word cr_alignment
300#ifdef MULTI_DABORT
301.LCprocfns:
302 .word processor
303#endif
304.LCfp:
305 .word fp_enter
306
307/*
308 * User mode handlers
309 *
310 * EABI note: sp_svc is always 64-bit aligned here, so should S_FRAME_SIZE
311 */
312
313#if defined(CONFIG_AEABI) && (__LINUX_ARM_ARCH__ >= 5) && (S_FRAME_SIZE & 7)
314#error "sizeof(struct pt_regs) must be a multiple of 8"
315#endif
316
317 .macro usr_entry
318 UNWIND(.fnstart )
319 UNWIND(.cantunwind ) @ don't unwind the user space
320 sub sp, sp, #S_FRAME_SIZE
321 ARM( stmib sp, {r1 - r12} )
322 THUMB( stmia sp, {r0 - r12} )
323
324 ldmia r0, {r3 - r5}
325 add r0, sp, #S_PC @ here for interlock avoidance
326 mov r6, #-1 @ "" "" "" ""
327
328 str r3, [sp] @ save the "real" r0 copied
329 @ from the exception stack
330
331 @
332 @ We are now ready to fill in the remaining blanks on the stack:
333 @
334 @ r4 - lr_<exception>, already fixed up for correct return/restart
335 @ r5 - spsr_<exception>
336 @ r6 - orig_r0 (see pt_regs definition in ptrace.h)
337 @
338 @ Also, separately save sp_usr and lr_usr
339 @
340 stmia r0, {r4 - r6}
341 ARM( stmdb r0, {sp, lr}^ )
342 THUMB( store_user_sp_lr r0, r1, S_SP - S_PC )
343
344 @
345 @ Enable the alignment trap while in kernel mode
346 @
347 alignment_trap r0
348
349 @
350 @ Clear FP to mark the first stack frame
351 @
352 zero_fp
353
354#ifdef CONFIG_IRQSOFF_TRACER
355 bl trace_hardirqs_off
356#endif
357 ct_user_exit save = 0
358 .endm
359
360 .macro kuser_cmpxchg_check
361#if !defined(CONFIG_CPU_32v6K) && defined(CONFIG_KUSER_HELPERS) && \
362 !defined(CONFIG_NEEDS_SYSCALL_FOR_CMPXCHG)
363#ifndef CONFIG_MMU
364#warning "NPTL on non MMU needs fixing"
365#else
366 @ Make sure our user space atomic helper is restarted
367 @ if it was interrupted in a critical region. Here we
368 @ perform a quick test inline since it should be false
369 @ 99.9999% of the time. The rest is done out of line.
370 cmp r4, #TASK_SIZE
371 blhs kuser_cmpxchg64_fixup
372#endif
373#endif
374 .endm
375
376 .align 5
377__dabt_usr:
378 usr_entry
379 kuser_cmpxchg_check
380 mov r2, sp
381 dabt_helper
382 b ret_from_exception
383 UNWIND(.fnend )
384ENDPROC(__dabt_usr)
385
386 .align 5
387__irq_usr:
388 usr_entry
389 kuser_cmpxchg_check
390 irq_handler
391 get_thread_info tsk
392 mov why, #0
393 b ret_to_user_from_irq
394 UNWIND(.fnend )
395ENDPROC(__irq_usr)
396
397 .ltorg
398
399 .align 5
400__und_usr:
401 usr_entry
402
403 mov r2, r4
404 mov r3, r5
405
406 @ r2 = regs->ARM_pc, which is either 2 or 4 bytes ahead of the
407 @ faulting instruction depending on Thumb mode.
408 @ r3 = regs->ARM_cpsr
409 @
410 @ The emulation code returns using r9 if it has emulated the
411 @ instruction, or the more conventional lr if we are to treat
412 @ this as a real undefined instruction
413 @
414 adr r9, BSYM(ret_from_exception)
415
416 tst r3, #PSR_T_BIT @ Thumb mode?
417 bne __und_usr_thumb
418 sub r4, r2, #4 @ ARM instr at LR - 4
4191: ldrt r0, [r4]
420 ARM_BE8(rev r0, r0) @ little endian instruction
421
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
428
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
4532: ldrht r5, [r4]
454ARM_BE8(rev16 r5, r5) @ little endian instruction
455 cmp r5, #0xe800 @ 32bit instruction if xx != 0
456 blo __und_usr_fault_16 @ 16bit undefined instruction
4573: ldrht r0, [r2]
458ARM_BE8(rev16 r0, r0) @ little endian instruction
459 add r2, r2, #2 @ r2 is PC + 2, make it PC + 4
460 str r2, [sp, #S_PC] @ it's a 2x16bit instr, update
461 orr r0, r0, r5, lsl #16
462 adr lr, BSYM(__und_usr_fault_32)
463 @ r0 = the two 16-bit Thumb instructions which caused the exception
464 @ r2 = PC value for the following Thumb instruction (:= regs->ARM_pc)
465 @ r4 = PC value for the first 16-bit Thumb instruction
466 @ lr = 32bit undefined instruction function
467
468#if __LINUX_ARM_ARCH__ < 7
469/* If the target arch was overridden, change it back: */
470#ifdef CONFIG_CPU_32v6K
471 .arch armv6k
472#else
473 .arch armv6
474#endif
475#endif /* __LINUX_ARM_ARCH__ < 7 */
476#else /* !(CONFIG_ARM_THUMB && __LINUX_ARM_ARCH__ >= 6 && CONFIG_CPU_V7) */
477 b __und_usr_fault_16
478#endif
479 UNWIND(.fnend)
480ENDPROC(__und_usr)
481
482/*
483 * The out of line fixup for the ldrt instructions above.
484 */
485 .pushsection .fixup, "ax"
486 .align 2
4874: mov pc, r9
488 .popsection
489 .pushsection __ex_table,"a"
490 .long 1b, 4b
491#if CONFIG_ARM_THUMB && __LINUX_ARM_ARCH__ >= 6 && CONFIG_CPU_V7
492 .long 2b, 4b
493 .long 3b, 4b
494#endif
495 .popsection
496
497/*
498 * Check whether the instruction is a co-processor instruction.
499 * If yes, we need to call the relevant co-processor handler.
500 *
501 * Note that we don't do a full check here for the co-processor
502 * instructions; all instructions with bit 27 set are well
503 * defined. The only instructions that should fault are the
504 * co-processor instructions. However, we have to watch out
505 * for the ARM6/ARM7 SWI bug.
506 *
507 * NEON is a special case that has to be handled here. Not all
508 * NEON instructions are co-processor instructions, so we have
509 * to make a special case of checking for them. Plus, there's
510 * five groups of them, so we have a table of mask/opcode pairs
511 * to check against, and if any match then we branch off into the
512 * NEON handler code.
513 *
514 * Emulators may wish to make use of the following registers:
515 * r0 = instruction opcode (32-bit ARM or two 16-bit Thumb)
516 * r2 = PC value to resume execution after successful emulation
517 * r9 = normal "successful" return address
518 * r10 = this threads thread_info structure
519 * lr = unrecognised instruction return address
520 * IRQs disabled, FIQs enabled.
521 */
522 @
523 @ Fall-through from Thumb-2 __und_usr
524 @
525#ifdef CONFIG_NEON
526 get_thread_info r10 @ get current thread
527 adr r6, .LCneon_thumb_opcodes
528 b 2f
529#endif
530call_fpe:
531 get_thread_info r10 @ get current thread
532#ifdef CONFIG_NEON
533 adr r6, .LCneon_arm_opcodes
5342: ldr r5, [r6], #4 @ mask value
535 ldr r7, [r6], #4 @ opcode bits matching in mask
536 cmp r5, #0 @ end mask?
537 beq 1f
538 and r8, r0, r5
539 cmp r8, r7 @ NEON instruction?
540 bne 2b
541 mov r7, #1
542 strb r7, [r10, #TI_USED_CP + 10] @ mark CP#10 as used
543 strb r7, [r10, #TI_USED_CP + 11] @ mark CP#11 as used
544 b do_vfp @ let VFP handler handle this
5451:
546#endif
547 tst r0, #0x08000000 @ only CDP/CPRT/LDC/STC have bit 27
548 tstne r0, #0x04000000 @ bit 26 set on both ARM and Thumb-2
549 moveq pc, lr
550 and r8, r0, #0x00000f00 @ mask out CP number
551 THUMB( lsr r8, r8, #8 )
552 mov r7, #1
553 add r6, r10, #TI_USED_CP
554 ARM( strb r7, [r6, r8, lsr #8] ) @ set appropriate used_cp[]
555 THUMB( strb r7, [r6, r8] ) @ set appropriate used_cp[]
556#ifdef CONFIG_IWMMXT
557 @ Test if we need to give access to iWMMXt coprocessors
558 ldr r5, [r10, #TI_FLAGS]
559 rsbs r7, r8, #(1 << 8) @ CP 0 or 1 only
560 movcss r7, r5, lsr #(TIF_USING_IWMMXT + 1)
561 bcs iwmmxt_task_enable
562#endif
563 ARM( add pc, pc, r8, lsr #6 )
564 THUMB( lsl r8, r8, #2 )
565 THUMB( add pc, r8 )
566 nop
567
568 movw_pc lr @ CP#0
569 W(b) do_fpe @ CP#1 (FPE)
570 W(b) do_fpe @ CP#2 (FPE)
571 movw_pc lr @ CP#3
572#ifdef CONFIG_CRUNCH
573 b crunch_task_enable @ CP#4 (MaverickCrunch)
574 b crunch_task_enable @ CP#5 (MaverickCrunch)
575 b crunch_task_enable @ CP#6 (MaverickCrunch)
576#else
577 movw_pc lr @ CP#4
578 movw_pc lr @ CP#5
579 movw_pc lr @ CP#6
580#endif
581 movw_pc lr @ CP#7
582 movw_pc lr @ CP#8
583 movw_pc lr @ CP#9
584#ifdef CONFIG_VFP
585 W(b) do_vfp @ CP#10 (VFP)
586 W(b) do_vfp @ CP#11 (VFP)
587#else
588 movw_pc lr @ CP#10 (VFP)
589 movw_pc lr @ CP#11 (VFP)
590#endif
591 movw_pc lr @ CP#12
592 movw_pc lr @ CP#13
593 movw_pc lr @ CP#14 (Debug)
594 movw_pc lr @ CP#15 (Control)
595
596#ifdef NEED_CPU_ARCHITECTURE
597 .align 2
598.LCcpu_architecture:
599 .word __cpu_architecture
600#endif
601
602#ifdef CONFIG_NEON
603 .align 6
604
605.LCneon_arm_opcodes:
606 .word 0xfe000000 @ mask
607 .word 0xf2000000 @ opcode
608
609 .word 0xff100000 @ mask
610 .word 0xf4000000 @ opcode
611
612 .word 0x00000000 @ mask
613 .word 0x00000000 @ opcode
614
615.LCneon_thumb_opcodes:
616 .word 0xef000000 @ mask
617 .word 0xef000000 @ opcode
618
619 .word 0xff100000 @ mask
620 .word 0xf9000000 @ opcode
621
622 .word 0x00000000 @ mask
623 .word 0x00000000 @ opcode
624#endif
625
626do_fpe:
627 enable_irq
628 ldr r4, .LCfp
629 add r10, r10, #TI_FPSTATE @ r10 = workspace
630 ldr pc, [r4] @ Call FP module USR entry point
631
632/*
633 * The FP module is called with these registers set:
634 * r0 = instruction
635 * r2 = PC+4
636 * r9 = normal "successful" return address
637 * r10 = FP workspace
638 * lr = unrecognised FP instruction return address
639 */
640
641 .pushsection .data
642ENTRY(fp_enter)
643 .word no_fp
644 .popsection
645
646ENTRY(no_fp)
647 mov pc, lr
648ENDPROC(no_fp)
649
650__und_usr_fault_32:
651 mov r1, #4
652 b 1f
653__und_usr_fault_16:
654 mov r1, #2
6551: enable_irq
656 mov r0, sp
657 adr lr, BSYM(ret_from_exception)
658 b __und_fault
659ENDPROC(__und_usr_fault_32)
660ENDPROC(__und_usr_fault_16)
661
662 .align 5
663__pabt_usr:
664 usr_entry
665 mov r2, sp @ regs
666 pabt_helper
667 UNWIND(.fnend )
668 /* fall through */
669/*
670 * This is the return code to user mode for abort handlers
671 */
672ENTRY(ret_from_exception)
673 UNWIND(.fnstart )
674 UNWIND(.cantunwind )
675 get_thread_info tsk
676 mov why, #0
677 b ret_to_user
678 UNWIND(.fnend )
679ENDPROC(__pabt_usr)
680ENDPROC(ret_from_exception)
681
682/*
683 * Register switch for ARMv3 and ARMv4 processors
684 * r0 = previous task_struct, r1 = previous thread_info, r2 = next thread_info
685 * previous and next are guaranteed not to be the same.
686 */
687ENTRY(__switch_to)
688 UNWIND(.fnstart )
689 UNWIND(.cantunwind )
690 add ip, r1, #TI_CPU_SAVE
691 ARM( stmia ip!, {r4 - sl, fp, sp, lr} ) @ Store most regs on stack
692 THUMB( stmia ip!, {r4 - sl, fp} ) @ Store most regs on stack
693 THUMB( str sp, [ip], #4 )
694 THUMB( str lr, [ip], #4 )
695 ldr r4, [r2, #TI_TP_VALUE]
696 ldr r5, [r2, #TI_TP_VALUE + 4]
697#ifdef CONFIG_CPU_USE_DOMAINS
698 ldr r6, [r2, #TI_CPU_DOMAIN]
699#endif
700 switch_tls r1, r4, r5, r3, r7
701#if defined(CONFIG_CC_STACKPROTECTOR) && !defined(CONFIG_SMP)
702 ldr r7, [r2, #TI_TASK]
703 ldr r8, =__stack_chk_guard
704 ldr r7, [r7, #TSK_STACK_CANARY]
705#endif
706#ifdef CONFIG_CPU_USE_DOMAINS
707 mcr p15, 0, r6, c3, c0, 0 @ Set domain register
708#endif
709 mov r5, r0
710 add r4, r2, #TI_CPU_SAVE
711 ldr r0, =thread_notify_head
712 mov r1, #THREAD_NOTIFY_SWITCH
713 bl atomic_notifier_call_chain
714#if defined(CONFIG_CC_STACKPROTECTOR) && !defined(CONFIG_SMP)
715 str r7, [r8]
716#endif
717 THUMB( mov ip, r4 )
718 mov r0, r5
719 ARM( ldmia r4, {r4 - sl, fp, sp, pc} ) @ Load all regs saved previously
720 THUMB( ldmia ip!, {r4 - sl, fp} ) @ Load all regs saved previously
721 THUMB( ldr sp, [ip], #4 )
722 THUMB( ldr pc, [ip] )
723 UNWIND(.fnend )
724ENDPROC(__switch_to)
725
726 __INIT
727
728/*
729 * User helpers.
730 *
731 * Each segment is 32-byte aligned and will be moved to the top of the high
732 * vector page. New segments (if ever needed) must be added in front of
733 * existing ones. This mechanism should be used only for things that are
734 * really small and justified, and not be abused freely.
735 *
736 * See Documentation/arm/kernel_user_helpers.txt for formal definitions.
737 */
738 THUMB( .arm )
739
740 .macro usr_ret, reg
741#ifdef CONFIG_ARM_THUMB
742 bx \reg
743#else
744 mov pc, \reg
745#endif
746 .endm
747
748 .macro kuser_pad, sym, size
749 .if (. - \sym) & 3
750 .rept 4 - (. - \sym) & 3
751 .byte 0
752 .endr
753 .endif
754 .rept (\size - (. - \sym)) / 4
755 .word 0xe7fddef1
756 .endr
757 .endm
758
759#ifdef CONFIG_KUSER_HELPERS
760 .align 5
761 .globl __kuser_helper_start
762__kuser_helper_start:
763
764/*
765 * Due to the length of some sequences, __kuser_cmpxchg64 spans 2 regular
766 * kuser "slots", therefore 0xffff0f80 is not used as a valid entry point.
767 */
768
769__kuser_cmpxchg64: @ 0xffff0f60
770
771#if defined(CONFIG_NEEDS_SYSCALL_FOR_CMPXCHG)
772
773 /*
774 * Poor you. No fast solution possible...
775 * The kernel itself must perform the operation.
776 * A special ghost syscall is used for that (see traps.c).
777 */
778 stmfd sp!, {r7, lr}
779 ldr r7, 1f @ it's 20 bits
780 swi __ARM_NR_cmpxchg64
781 ldmfd sp!, {r7, pc}
7821: .word __ARM_NR_cmpxchg64
783
784#elif defined(CONFIG_CPU_32v6K)
785
786 stmfd sp!, {r4, r5, r6, r7}
787 ldrd r4, r5, [r0] @ load old val
788 ldrd r6, r7, [r1] @ load new val
789 smp_dmb arm
7901: ldrexd r0, r1, [r2] @ load current val
791 eors r3, r0, r4 @ compare with oldval (1)
792 eoreqs r3, r1, r5 @ compare with oldval (2)
793 strexdeq r3, r6, r7, [r2] @ store newval if eq
794 teqeq r3, #1 @ success?
795 beq 1b @ if no then retry
796 smp_dmb arm
797 rsbs r0, r3, #0 @ set returned val and C flag
798 ldmfd sp!, {r4, r5, r6, r7}
799 usr_ret lr
800
801#elif !defined(CONFIG_SMP)
802
803#ifdef CONFIG_MMU
804
805 /*
806 * The only thing that can break atomicity in this cmpxchg64
807 * implementation is either an IRQ or a data abort exception
808 * causing another process/thread to be scheduled in the middle of
809 * the critical sequence. The same strategy as for cmpxchg is used.
810 */
811 stmfd sp!, {r4, r5, r6, lr}
812 ldmia r0, {r4, r5} @ load old val
813 ldmia r1, {r6, lr} @ load new val
8141: ldmia r2, {r0, r1} @ load current val
815 eors r3, r0, r4 @ compare with oldval (1)
816 eoreqs r3, r1, r5 @ compare with oldval (2)
8172: stmeqia r2, {r6, lr} @ store newval if eq
818 rsbs r0, r3, #0 @ set return val and C flag
819 ldmfd sp!, {r4, r5, r6, pc}
820
821 .text
822kuser_cmpxchg64_fixup:
823 @ Called from kuser_cmpxchg_fixup.
824 @ r4 = address of interrupted insn (must be preserved).
825 @ sp = saved regs. r7 and r8 are clobbered.
826 @ 1b = first critical insn, 2b = last critical insn.
827 @ If r4 >= 1b and r4 <= 2b then saved pc_usr is set to 1b.
828 mov r7, #0xffff0fff
829 sub r7, r7, #(0xffff0fff - (0xffff0f60 + (1b - __kuser_cmpxchg64)))
830 subs r8, r4, r7
831 rsbcss r8, r8, #(2b - 1b)
832 strcs r7, [sp, #S_PC]
833#if __LINUX_ARM_ARCH__ < 6
834 bcc kuser_cmpxchg32_fixup
835#endif
836 mov pc, lr
837 .previous
838
839#else
840#warning "NPTL on non MMU needs fixing"
841 mov r0, #-1
842 adds r0, r0, #0
843 usr_ret lr
844#endif
845
846#else
847#error "incoherent kernel configuration"
848#endif
849
850 kuser_pad __kuser_cmpxchg64, 64
851
852__kuser_memory_barrier: @ 0xffff0fa0
853 smp_dmb arm
854 usr_ret lr
855
856 kuser_pad __kuser_memory_barrier, 32
857
858__kuser_cmpxchg: @ 0xffff0fc0
859
860#if defined(CONFIG_NEEDS_SYSCALL_FOR_CMPXCHG)
861
862 /*
863 * Poor you. No fast solution possible...
864 * The kernel itself must perform the operation.
865 * A special ghost syscall is used for that (see traps.c).
866 */
867 stmfd sp!, {r7, lr}
868 ldr r7, 1f @ it's 20 bits
869 swi __ARM_NR_cmpxchg
870 ldmfd sp!, {r7, pc}
8711: .word __ARM_NR_cmpxchg
872
873#elif __LINUX_ARM_ARCH__ < 6
874
875#ifdef CONFIG_MMU
876
877 /*
878 * The only thing that can break atomicity in this cmpxchg
879 * implementation is either an IRQ or a data abort exception
880 * causing another process/thread to be scheduled in the middle
881 * of the critical sequence. To prevent this, code is added to
882 * the IRQ and data abort exception handlers to set the pc back
883 * to the beginning of the critical section if it is found to be
884 * within that critical section (see kuser_cmpxchg_fixup).
885 */
8861: ldr r3, [r2] @ load current val
887 subs r3, r3, r0 @ compare with oldval
8882: streq r1, [r2] @ store newval if eq
889 rsbs r0, r3, #0 @ set return val and C flag
890 usr_ret lr
891
892 .text
893kuser_cmpxchg32_fixup:
894 @ Called from kuser_cmpxchg_check macro.
895 @ r4 = address of interrupted insn (must be preserved).
896 @ sp = saved regs. r7 and r8 are clobbered.
897 @ 1b = first critical insn, 2b = last critical insn.
898 @ If r4 >= 1b and r4 <= 2b then saved pc_usr is set to 1b.
899 mov r7, #0xffff0fff
900 sub r7, r7, #(0xffff0fff - (0xffff0fc0 + (1b - __kuser_cmpxchg)))
901 subs r8, r4, r7
902 rsbcss r8, r8, #(2b - 1b)
903 strcs r7, [sp, #S_PC]
904 mov pc, lr
905 .previous
906
907#else
908#warning "NPTL on non MMU needs fixing"
909 mov r0, #-1
910 adds r0, r0, #0
911 usr_ret lr
912#endif
913
914#else
915
916 smp_dmb arm
9171: ldrex r3, [r2]
918 subs r3, r3, r0
919 strexeq r3, r1, [r2]
920 teqeq r3, #1
921 beq 1b
922 rsbs r0, r3, #0
923 /* beware -- each __kuser slot must be 8 instructions max */
924 ALT_SMP(b __kuser_memory_barrier)
925 ALT_UP(usr_ret lr)
926
927#endif
928
929 kuser_pad __kuser_cmpxchg, 32
930
931__kuser_get_tls: @ 0xffff0fe0
932 ldr r0, [pc, #(16 - 8)] @ read TLS, set in kuser_get_tls_init
933 usr_ret lr
934 mrc p15, 0, r0, c13, c0, 3 @ 0xffff0fe8 hardware TLS code
935 kuser_pad __kuser_get_tls, 16
936 .rep 3
937 .word 0 @ 0xffff0ff0 software TLS value, then
938 .endr @ pad up to __kuser_helper_version
939
940__kuser_helper_version: @ 0xffff0ffc
941 .word ((__kuser_helper_end - __kuser_helper_start) >> 5)
942
943 .globl __kuser_helper_end
944__kuser_helper_end:
945
946#endif
947
948 THUMB( .thumb )
949
950/*
951 * Vector stubs.
952 *
953 * This code is copied to 0xffff1000 so we can use branches in the
954 * vectors, rather than ldr's. Note that this code must not exceed
955 * a page size.
956 *
957 * Common stub entry macro:
958 * Enter in IRQ mode, spsr = SVC/USR CPSR, lr = SVC/USR PC
959 *
960 * SP points to a minimal amount of processor-private memory, the address
961 * of which is copied into r0 for the mode specific abort handler.
962 */
963 .macro vector_stub, name, mode, correction=0
964 .align 5
965
966vector_\name:
967 .if \correction
968 sub lr, lr, #\correction
969 .endif
970
971 @
972 @ Save r0, lr_<exception> (parent PC) and spsr_<exception>
973 @ (parent CPSR)
974 @
975 stmia sp, {r0, lr} @ save r0, lr
976 mrs lr, spsr
977 str lr, [sp, #8] @ save spsr
978
979 @
980 @ Prepare for SVC32 mode. IRQs remain disabled.
981 @
982 mrs r0, cpsr
983 eor r0, r0, #(\mode ^ SVC_MODE | PSR_ISETSTATE)
984 msr spsr_cxsf, r0
985
986 @
987 @ the branch table must immediately follow this code
988 @
989 and lr, lr, #0x0f
990 THUMB( adr r0, 1f )
991 THUMB( ldr lr, [r0, lr, lsl #2] )
992 mov r0, sp
993 ARM( ldr lr, [pc, lr, lsl #2] )
994 movs pc, lr @ branch to handler in SVC mode
995ENDPROC(vector_\name)
996
997 .align 2
998 @ handler addresses follow this label
9991:
1000 .endm
1001
1002 .section .stubs, "ax", %progbits
1003__stubs_start:
1004 @ This must be the first word
1005 .word vector_swi
1006
1007vector_rst:
1008 ARM( swi SYS_ERROR0 )
1009 THUMB( svc #0 )
1010 THUMB( nop )
1011 b vector_und
1012
1013/*
1014 * Interrupt dispatcher
1015 */
1016 vector_stub irq, IRQ_MODE, 4
1017
1018 .long __irq_usr @ 0 (USR_26 / USR_32)
1019 .long __irq_invalid @ 1 (FIQ_26 / FIQ_32)
1020 .long __irq_invalid @ 2 (IRQ_26 / IRQ_32)
1021 .long __irq_svc @ 3 (SVC_26 / SVC_32)
1022 .long __irq_invalid @ 4
1023 .long __irq_invalid @ 5
1024 .long __irq_invalid @ 6
1025 .long __irq_invalid @ 7
1026 .long __irq_invalid @ 8
1027 .long __irq_invalid @ 9
1028 .long __irq_invalid @ a
1029 .long __irq_invalid @ b
1030 .long __irq_invalid @ c
1031 .long __irq_invalid @ d
1032 .long __irq_invalid @ e
1033 .long __irq_invalid @ f
1034
1035/*
1036 * Data abort dispatcher
1037 * Enter in ABT mode, spsr = USR CPSR, lr = USR PC
1038 */
1039 vector_stub dabt, ABT_MODE, 8
1040
1041 .long __dabt_usr @ 0 (USR_26 / USR_32)
1042 .long __dabt_invalid @ 1 (FIQ_26 / FIQ_32)
1043 .long __dabt_invalid @ 2 (IRQ_26 / IRQ_32)
1044 .long __dabt_svc @ 3 (SVC_26 / SVC_32)
1045 .long __dabt_invalid @ 4
1046 .long __dabt_invalid @ 5
1047 .long __dabt_invalid @ 6
1048 .long __dabt_invalid @ 7
1049 .long __dabt_invalid @ 8
1050 .long __dabt_invalid @ 9
1051 .long __dabt_invalid @ a
1052 .long __dabt_invalid @ b
1053 .long __dabt_invalid @ c
1054 .long __dabt_invalid @ d
1055 .long __dabt_invalid @ e
1056 .long __dabt_invalid @ f
1057
1058/*
1059 * Prefetch abort dispatcher
1060 * Enter in ABT mode, spsr = USR CPSR, lr = USR PC
1061 */
1062 vector_stub pabt, ABT_MODE, 4
1063
1064 .long __pabt_usr @ 0 (USR_26 / USR_32)
1065 .long __pabt_invalid @ 1 (FIQ_26 / FIQ_32)
1066 .long __pabt_invalid @ 2 (IRQ_26 / IRQ_32)
1067 .long __pabt_svc @ 3 (SVC_26 / SVC_32)
1068 .long __pabt_invalid @ 4
1069 .long __pabt_invalid @ 5
1070 .long __pabt_invalid @ 6
1071 .long __pabt_invalid @ 7
1072 .long __pabt_invalid @ 8
1073 .long __pabt_invalid @ 9
1074 .long __pabt_invalid @ a
1075 .long __pabt_invalid @ b
1076 .long __pabt_invalid @ c
1077 .long __pabt_invalid @ d
1078 .long __pabt_invalid @ e
1079 .long __pabt_invalid @ f
1080
1081/*
1082 * Undef instr entry dispatcher
1083 * Enter in UND mode, spsr = SVC/USR CPSR, lr = SVC/USR PC
1084 */
1085 vector_stub und, UND_MODE
1086
1087 .long __und_usr @ 0 (USR_26 / USR_32)
1088 .long __und_invalid @ 1 (FIQ_26 / FIQ_32)
1089 .long __und_invalid @ 2 (IRQ_26 / IRQ_32)
1090 .long __und_svc @ 3 (SVC_26 / SVC_32)
1091 .long __und_invalid @ 4
1092 .long __und_invalid @ 5
1093 .long __und_invalid @ 6
1094 .long __und_invalid @ 7
1095 .long __und_invalid @ 8
1096 .long __und_invalid @ 9
1097 .long __und_invalid @ a
1098 .long __und_invalid @ b
1099 .long __und_invalid @ c
1100 .long __und_invalid @ d
1101 .long __und_invalid @ e
1102 .long __und_invalid @ f
1103
1104 .align 5
1105
1106/*=============================================================================
1107 * Address exception handler
1108 *-----------------------------------------------------------------------------
1109 * These aren't too critical.
1110 * (they're not supposed to happen, and won't happen in 32-bit data mode).
1111 */
1112
1113vector_addrexcptn:
1114 b vector_addrexcptn
1115
1116/*=============================================================================
1117 * Undefined FIQs
1118 *-----------------------------------------------------------------------------
1119 * Enter in FIQ mode, spsr = ANY CPSR, lr = ANY PC
1120 * MUST PRESERVE SVC SPSR, but need to switch to SVC mode to show our msg.
1121 * Basically to switch modes, we *HAVE* to clobber one register... brain
1122 * damage alert! I don't think that we can execute any code in here in any
1123 * other mode than FIQ... Ok you can switch to another mode, but you can't
1124 * get out of that mode without clobbering one register.
1125 */
1126vector_fiq:
1127 subs pc, lr, #4
1128
1129 .globl vector_fiq_offset
1130 .equ vector_fiq_offset, vector_fiq
1131
1132 .section .vectors, "ax", %progbits
1133__vectors_start:
1134 W(b) vector_rst
1135 W(b) vector_und
1136 W(ldr) pc, __vectors_start + 0x1000
1137 W(b) vector_pabt
1138 W(b) vector_dabt
1139 W(b) vector_addrexcptn
1140 W(b) vector_irq
1141 W(b) vector_fiq
1142
1143 .data
1144
1145 .globl cr_alignment
1146 .globl cr_no_alignment
1147cr_alignment:
1148 .space 4
1149cr_no_alignment:
1150 .space 4
1151
1152#ifdef CONFIG_MULTI_IRQ_HANDLER
1153 .globl handle_arch_irq
1154handle_arch_irq:
1155 .space 4
1156#endif
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
509997:
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, #PT_REGS_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
106ENDPROC(__pabt_invalid)
107
108__dabt_invalid:
109 inv_entry BAD_DATA
110 b common_invalid
111ENDPROC(__dabt_invalid)
112
113__irq_invalid:
114 inv_entry BAD_IRQ
115 b common_invalid
116ENDPROC(__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@
128common_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
140ENDPROC(__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, #(SVC_REGS_SIZE + \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, #(SVC_REGS_SIZE + \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 get_thread_info tsk
189 ldr r0, [tsk, #TI_ADDR_LIMIT]
190 mov r1, #TASK_SIZE
191 str r1, [tsk, #TI_ADDR_LIMIT]
192 str r0, [sp, #SVC_ADDR_LIMIT]
193
194 uaccess_save r0
195 .if \uaccess
196 uaccess_disable r0
197 .endif
198
199 .if \trace
200#ifdef CONFIG_TRACE_IRQFLAGS
201 bl trace_hardirqs_off
202#endif
203 .endif
204 .endm
205
206 .align 5
207__dabt_svc:
208 svc_entry uaccess=0
209 mov r2, sp
210 dabt_helper
211 THUMB( ldr r5, [sp, #S_PSR] ) @ potentially updated CPSR
212 svc_exit r5 @ return from exception
213 UNWIND(.fnend )
214ENDPROC(__dabt_svc)
215
216 .align 5
217__irq_svc:
218 svc_entry
219 irq_handler
220
221#ifdef CONFIG_PREEMPT
222 ldr r8, [tsk, #TI_PREEMPT] @ get preempt count
223 ldr r0, [tsk, #TI_FLAGS] @ get flags
224 teq r8, #0 @ if preempt count != 0
225 movne r0, #0 @ force flags to 0
226 tst r0, #_TIF_NEED_RESCHED
227 blne svc_preempt
228#endif
229
230 svc_exit r5, irq = 1 @ return from exception
231 UNWIND(.fnend )
232ENDPROC(__irq_svc)
233
234 .ltorg
235
236#ifdef CONFIG_PREEMPT
237svc_preempt:
238 mov r8, lr
2391: bl preempt_schedule_irq @ irq en/disable is done inside
240 ldr r0, [tsk, #TI_FLAGS] @ get new tasks TI_FLAGS
241 tst r0, #_TIF_NEED_RESCHED
242 reteq r8 @ go again
243 b 1b
244#endif
245
246__und_fault:
247 @ Correct the PC such that it is pointing at the instruction
248 @ which caused the fault. If the faulting instruction was ARM
249 @ the PC will be pointing at the next instruction, and have to
250 @ subtract 4. Otherwise, it is Thumb, and the PC will be
251 @ pointing at the second half of the Thumb instruction. We
252 @ have to subtract 2.
253 ldr r2, [r0, #S_PC]
254 sub r2, r2, r1
255 str r2, [r0, #S_PC]
256 b do_undefinstr
257ENDPROC(__und_fault)
258
259 .align 5
260__und_svc:
261#ifdef CONFIG_KPROBES
262 @ If a kprobe is about to simulate a "stmdb sp..." instruction,
263 @ it obviously needs free stack space which then will belong to
264 @ the saved context.
265 svc_entry MAX_STACK_SIZE
266#else
267 svc_entry
268#endif
269 @
270 @ call emulation code, which returns using r9 if it has emulated
271 @ the instruction, or the more conventional lr if we are to treat
272 @ this as a real undefined instruction
273 @
274 @ r0 - instruction
275 @
276#ifndef CONFIG_THUMB2_KERNEL
277 ldr r0, [r4, #-4]
278#else
279 mov r1, #2
280 ldrh r0, [r4, #-2] @ Thumb instruction at LR - 2
281 cmp r0, #0xe800 @ 32-bit instruction if xx >= 0
282 blo __und_svc_fault
283 ldrh r9, [r4] @ bottom 16 bits
284 add r4, r4, #2
285 str r4, [sp, #S_PC]
286 orr r0, r9, r0, lsl #16
287#endif
288 badr r9, __und_svc_finish
289 mov r2, r4
290 bl call_fpe
291
292 mov r1, #4 @ PC correction to apply
293__und_svc_fault:
294 mov r0, sp @ struct pt_regs *regs
295 bl __und_fault
296
297__und_svc_finish:
298 get_thread_info tsk
299 ldr r5, [sp, #S_PSR] @ Get SVC cpsr
300 svc_exit r5 @ return from exception
301 UNWIND(.fnend )
302ENDPROC(__und_svc)
303
304 .align 5
305__pabt_svc:
306 svc_entry
307 mov r2, sp @ regs
308 pabt_helper
309 svc_exit r5 @ return from exception
310 UNWIND(.fnend )
311ENDPROC(__pabt_svc)
312
313 .align 5
314__fiq_svc:
315 svc_entry trace=0
316 mov r0, sp @ struct pt_regs *regs
317 bl handle_fiq_as_nmi
318 svc_exit_via_fiq
319 UNWIND(.fnend )
320ENDPROC(__fiq_svc)
321
322 .align 5
323.LCcralign:
324 .word cr_alignment
325#ifdef MULTI_DABORT
326.LCprocfns:
327 .word processor
328#endif
329.LCfp:
330 .word fp_enter
331
332/*
333 * Abort mode handlers
334 */
335
336@
337@ Taking a FIQ in abort mode is similar to taking a FIQ in SVC mode
338@ and reuses the same macros. However in abort mode we must also
339@ save/restore lr_abt and spsr_abt to make nested aborts safe.
340@
341 .align 5
342__fiq_abt:
343 svc_entry trace=0
344
345 ARM( msr cpsr_c, #ABT_MODE | PSR_I_BIT | PSR_F_BIT )
346 THUMB( mov r0, #ABT_MODE | PSR_I_BIT | PSR_F_BIT )
347 THUMB( msr cpsr_c, r0 )
348 mov r1, lr @ Save lr_abt
349 mrs r2, spsr @ Save spsr_abt, abort is now safe
350 ARM( msr cpsr_c, #SVC_MODE | PSR_I_BIT | PSR_F_BIT )
351 THUMB( mov r0, #SVC_MODE | PSR_I_BIT | PSR_F_BIT )
352 THUMB( msr cpsr_c, r0 )
353 stmfd sp!, {r1 - r2}
354
355 add r0, sp, #8 @ struct pt_regs *regs
356 bl handle_fiq_as_nmi
357
358 ldmfd sp!, {r1 - r2}
359 ARM( msr cpsr_c, #ABT_MODE | PSR_I_BIT | PSR_F_BIT )
360 THUMB( mov r0, #ABT_MODE | PSR_I_BIT | PSR_F_BIT )
361 THUMB( msr cpsr_c, r0 )
362 mov lr, r1 @ Restore lr_abt, abort is unsafe
363 msr spsr_cxsf, r2 @ Restore spsr_abt
364 ARM( msr cpsr_c, #SVC_MODE | PSR_I_BIT | PSR_F_BIT )
365 THUMB( mov r0, #SVC_MODE | PSR_I_BIT | PSR_F_BIT )
366 THUMB( msr cpsr_c, r0 )
367
368 svc_exit_via_fiq
369 UNWIND(.fnend )
370ENDPROC(__fiq_abt)
371
372/*
373 * User mode handlers
374 *
375 * EABI note: sp_svc is always 64-bit aligned here, so should PT_REGS_SIZE
376 */
377
378#if defined(CONFIG_AEABI) && (__LINUX_ARM_ARCH__ >= 5) && (PT_REGS_SIZE & 7)
379#error "sizeof(struct pt_regs) must be a multiple of 8"
380#endif
381
382 .macro usr_entry, trace=1, uaccess=1
383 UNWIND(.fnstart )
384 UNWIND(.cantunwind ) @ don't unwind the user space
385 sub sp, sp, #PT_REGS_SIZE
386 ARM( stmib sp, {r1 - r12} )
387 THUMB( stmia sp, {r0 - r12} )
388
389 ATRAP( mrc p15, 0, r7, c1, c0, 0)
390 ATRAP( ldr r8, .LCcralign)
391
392 ldmia r0, {r3 - r5}
393 add r0, sp, #S_PC @ here for interlock avoidance
394 mov r6, #-1 @ "" "" "" ""
395
396 str r3, [sp] @ save the "real" r0 copied
397 @ from the exception stack
398
399 ATRAP( ldr r8, [r8, #0])
400
401 @
402 @ We are now ready to fill in the remaining blanks on the stack:
403 @
404 @ r4 - lr_<exception>, already fixed up for correct return/restart
405 @ r5 - spsr_<exception>
406 @ r6 - orig_r0 (see pt_regs definition in ptrace.h)
407 @
408 @ Also, separately save sp_usr and lr_usr
409 @
410 stmia r0, {r4 - r6}
411 ARM( stmdb r0, {sp, lr}^ )
412 THUMB( store_user_sp_lr r0, r1, S_SP - S_PC )
413
414 .if \uaccess
415 uaccess_disable ip
416 .endif
417
418 @ Enable the alignment trap while in kernel mode
419 ATRAP( teq r8, r7)
420 ATRAP( mcrne p15, 0, r8, c1, c0, 0)
421
422 @
423 @ Clear FP to mark the first stack frame
424 @
425 zero_fp
426
427 .if \trace
428#ifdef CONFIG_TRACE_IRQFLAGS
429 bl trace_hardirqs_off
430#endif
431 ct_user_exit save = 0
432 .endif
433 .endm
434
435 .macro kuser_cmpxchg_check
436#if !defined(CONFIG_CPU_32v6K) && defined(CONFIG_KUSER_HELPERS)
437#ifndef CONFIG_MMU
438#warning "NPTL on non MMU needs fixing"
439#else
440 @ Make sure our user space atomic helper is restarted
441 @ if it was interrupted in a critical region. Here we
442 @ perform a quick test inline since it should be false
443 @ 99.9999% of the time. The rest is done out of line.
444 cmp r4, #TASK_SIZE
445 blhs kuser_cmpxchg64_fixup
446#endif
447#endif
448 .endm
449
450 .align 5
451__dabt_usr:
452 usr_entry uaccess=0
453 kuser_cmpxchg_check
454 mov r2, sp
455 dabt_helper
456 b ret_from_exception
457 UNWIND(.fnend )
458ENDPROC(__dabt_usr)
459
460 .align 5
461__irq_usr:
462 usr_entry
463 kuser_cmpxchg_check
464 irq_handler
465 get_thread_info tsk
466 mov why, #0
467 b ret_to_user_from_irq
468 UNWIND(.fnend )
469ENDPROC(__irq_usr)
470
471 .ltorg
472
473 .align 5
474__und_usr:
475 usr_entry uaccess=0
476
477 mov r2, r4
478 mov r3, r5
479
480 @ r2 = regs->ARM_pc, which is either 2 or 4 bytes ahead of the
481 @ faulting instruction depending on Thumb mode.
482 @ r3 = regs->ARM_cpsr
483 @
484 @ The emulation code returns using r9 if it has emulated the
485 @ instruction, or the more conventional lr if we are to treat
486 @ this as a real undefined instruction
487 @
488 badr r9, ret_from_exception
489
490 @ IRQs must be enabled before attempting to read the instruction from
491 @ user space since that could cause a page/translation fault if the
492 @ page table was modified by another CPU.
493 enable_irq
494
495 tst r3, #PSR_T_BIT @ Thumb mode?
496 bne __und_usr_thumb
497 sub r4, r2, #4 @ ARM instr at LR - 4
4981: ldrt r0, [r4]
499 ARM_BE8(rev r0, r0) @ little endian instruction
500
501 uaccess_disable ip
502
503 @ r0 = 32-bit ARM instruction which caused the exception
504 @ r2 = PC value for the following instruction (:= regs->ARM_pc)
505 @ r4 = PC value for the faulting instruction
506 @ lr = 32-bit undefined instruction function
507 badr lr, __und_usr_fault_32
508 b call_fpe
509
510__und_usr_thumb:
511 @ Thumb instruction
512 sub r4, r2, #2 @ First half of thumb instr at LR - 2
513#if CONFIG_ARM_THUMB && __LINUX_ARM_ARCH__ >= 6 && CONFIG_CPU_V7
514/*
515 * Thumb-2 instruction handling. Note that because pre-v6 and >= v6 platforms
516 * can never be supported in a single kernel, this code is not applicable at
517 * all when __LINUX_ARM_ARCH__ < 6. This allows simplifying assumptions to be
518 * made about .arch directives.
519 */
520#if __LINUX_ARM_ARCH__ < 7
521/* If the target CPU may not be Thumb-2-capable, a run-time check is needed: */
522#define NEED_CPU_ARCHITECTURE
523 ldr r5, .LCcpu_architecture
524 ldr r5, [r5]
525 cmp r5, #CPU_ARCH_ARMv7
526 blo __und_usr_fault_16 @ 16bit undefined instruction
527/*
528 * The following code won't get run unless the running CPU really is v7, so
529 * coding round the lack of ldrht on older arches is pointless. Temporarily
530 * override the assembler target arch with the minimum required instead:
531 */
532 .arch armv6t2
533#endif
5342: ldrht r5, [r4]
535ARM_BE8(rev16 r5, r5) @ little endian instruction
536 cmp r5, #0xe800 @ 32bit instruction if xx != 0
537 blo __und_usr_fault_16_pan @ 16bit undefined instruction
5383: ldrht r0, [r2]
539ARM_BE8(rev16 r0, r0) @ little endian instruction
540 uaccess_disable ip
541 add r2, r2, #2 @ r2 is PC + 2, make it PC + 4
542 str r2, [sp, #S_PC] @ it's a 2x16bit instr, update
543 orr r0, r0, r5, lsl #16
544 badr lr, __und_usr_fault_32
545 @ r0 = the two 16-bit Thumb instructions which caused the exception
546 @ r2 = PC value for the following Thumb instruction (:= regs->ARM_pc)
547 @ r4 = PC value for the first 16-bit Thumb instruction
548 @ lr = 32bit undefined instruction function
549
550#if __LINUX_ARM_ARCH__ < 7
551/* If the target arch was overridden, change it back: */
552#ifdef CONFIG_CPU_32v6K
553 .arch armv6k
554#else
555 .arch armv6
556#endif
557#endif /* __LINUX_ARM_ARCH__ < 7 */
558#else /* !(CONFIG_ARM_THUMB && __LINUX_ARM_ARCH__ >= 6 && CONFIG_CPU_V7) */
559 b __und_usr_fault_16
560#endif
561 UNWIND(.fnend)
562ENDPROC(__und_usr)
563
564/*
565 * The out of line fixup for the ldrt instructions above.
566 */
567 .pushsection .text.fixup, "ax"
568 .align 2
5694: str r4, [sp, #S_PC] @ retry current instruction
570 ret r9
571 .popsection
572 .pushsection __ex_table,"a"
573 .long 1b, 4b
574#if CONFIG_ARM_THUMB && __LINUX_ARM_ARCH__ >= 6 && CONFIG_CPU_V7
575 .long 2b, 4b
576 .long 3b, 4b
577#endif
578 .popsection
579
580/*
581 * Check whether the instruction is a co-processor instruction.
582 * If yes, we need to call the relevant co-processor handler.
583 *
584 * Note that we don't do a full check here for the co-processor
585 * instructions; all instructions with bit 27 set are well
586 * defined. The only instructions that should fault are the
587 * co-processor instructions. However, we have to watch out
588 * for the ARM6/ARM7 SWI bug.
589 *
590 * NEON is a special case that has to be handled here. Not all
591 * NEON instructions are co-processor instructions, so we have
592 * to make a special case of checking for them. Plus, there's
593 * five groups of them, so we have a table of mask/opcode pairs
594 * to check against, and if any match then we branch off into the
595 * NEON handler code.
596 *
597 * Emulators may wish to make use of the following registers:
598 * r0 = instruction opcode (32-bit ARM or two 16-bit Thumb)
599 * r2 = PC value to resume execution after successful emulation
600 * r9 = normal "successful" return address
601 * r10 = this threads thread_info structure
602 * lr = unrecognised instruction return address
603 * IRQs enabled, FIQs enabled.
604 */
605 @
606 @ Fall-through from Thumb-2 __und_usr
607 @
608#ifdef CONFIG_NEON
609 get_thread_info r10 @ get current thread
610 adr r6, .LCneon_thumb_opcodes
611 b 2f
612#endif
613call_fpe:
614 get_thread_info r10 @ get current thread
615#ifdef CONFIG_NEON
616 adr r6, .LCneon_arm_opcodes
6172: ldr r5, [r6], #4 @ mask value
618 ldr r7, [r6], #4 @ opcode bits matching in mask
619 cmp r5, #0 @ end mask?
620 beq 1f
621 and r8, r0, r5
622 cmp r8, r7 @ NEON instruction?
623 bne 2b
624 mov r7, #1
625 strb r7, [r10, #TI_USED_CP + 10] @ mark CP#10 as used
626 strb r7, [r10, #TI_USED_CP + 11] @ mark CP#11 as used
627 b do_vfp @ let VFP handler handle this
6281:
629#endif
630 tst r0, #0x08000000 @ only CDP/CPRT/LDC/STC have bit 27
631 tstne r0, #0x04000000 @ bit 26 set on both ARM and Thumb-2
632 reteq lr
633 and r8, r0, #0x00000f00 @ mask out CP number
634 THUMB( lsr r8, r8, #8 )
635 mov r7, #1
636 add r6, r10, #TI_USED_CP
637 ARM( strb r7, [r6, r8, lsr #8] ) @ set appropriate used_cp[]
638 THUMB( strb r7, [r6, r8] ) @ set appropriate used_cp[]
639#ifdef CONFIG_IWMMXT
640 @ Test if we need to give access to iWMMXt coprocessors
641 ldr r5, [r10, #TI_FLAGS]
642 rsbs r7, r8, #(1 << 8) @ CP 0 or 1 only
643 movcss r7, r5, lsr #(TIF_USING_IWMMXT + 1)
644 bcs iwmmxt_task_enable
645#endif
646 ARM( add pc, pc, r8, lsr #6 )
647 THUMB( lsl r8, r8, #2 )
648 THUMB( add pc, r8 )
649 nop
650
651 ret.w lr @ CP#0
652 W(b) do_fpe @ CP#1 (FPE)
653 W(b) do_fpe @ CP#2 (FPE)
654 ret.w lr @ CP#3
655#ifdef CONFIG_CRUNCH
656 b crunch_task_enable @ CP#4 (MaverickCrunch)
657 b crunch_task_enable @ CP#5 (MaverickCrunch)
658 b crunch_task_enable @ CP#6 (MaverickCrunch)
659#else
660 ret.w lr @ CP#4
661 ret.w lr @ CP#5
662 ret.w lr @ CP#6
663#endif
664 ret.w lr @ CP#7
665 ret.w lr @ CP#8
666 ret.w lr @ CP#9
667#ifdef CONFIG_VFP
668 W(b) do_vfp @ CP#10 (VFP)
669 W(b) do_vfp @ CP#11 (VFP)
670#else
671 ret.w lr @ CP#10 (VFP)
672 ret.w lr @ CP#11 (VFP)
673#endif
674 ret.w lr @ CP#12
675 ret.w lr @ CP#13
676 ret.w lr @ CP#14 (Debug)
677 ret.w lr @ CP#15 (Control)
678
679#ifdef NEED_CPU_ARCHITECTURE
680 .align 2
681.LCcpu_architecture:
682 .word __cpu_architecture
683#endif
684
685#ifdef CONFIG_NEON
686 .align 6
687
688.LCneon_arm_opcodes:
689 .word 0xfe000000 @ mask
690 .word 0xf2000000 @ opcode
691
692 .word 0xff100000 @ mask
693 .word 0xf4000000 @ opcode
694
695 .word 0x00000000 @ mask
696 .word 0x00000000 @ opcode
697
698.LCneon_thumb_opcodes:
699 .word 0xef000000 @ mask
700 .word 0xef000000 @ opcode
701
702 .word 0xff100000 @ mask
703 .word 0xf9000000 @ opcode
704
705 .word 0x00000000 @ mask
706 .word 0x00000000 @ opcode
707#endif
708
709do_fpe:
710 ldr r4, .LCfp
711 add r10, r10, #TI_FPSTATE @ r10 = workspace
712 ldr pc, [r4] @ Call FP module USR entry point
713
714/*
715 * The FP module is called with these registers set:
716 * r0 = instruction
717 * r2 = PC+4
718 * r9 = normal "successful" return address
719 * r10 = FP workspace
720 * lr = unrecognised FP instruction return address
721 */
722
723 .pushsection .data
724ENTRY(fp_enter)
725 .word no_fp
726 .popsection
727
728ENTRY(no_fp)
729 ret lr
730ENDPROC(no_fp)
731
732__und_usr_fault_32:
733 mov r1, #4
734 b 1f
735__und_usr_fault_16_pan:
736 uaccess_disable ip
737__und_usr_fault_16:
738 mov r1, #2
7391: mov r0, sp
740 badr lr, ret_from_exception
741 b __und_fault
742ENDPROC(__und_usr_fault_32)
743ENDPROC(__und_usr_fault_16)
744
745 .align 5
746__pabt_usr:
747 usr_entry
748 mov r2, sp @ regs
749 pabt_helper
750 UNWIND(.fnend )
751 /* fall through */
752/*
753 * This is the return code to user mode for abort handlers
754 */
755ENTRY(ret_from_exception)
756 UNWIND(.fnstart )
757 UNWIND(.cantunwind )
758 get_thread_info tsk
759 mov why, #0
760 b ret_to_user
761 UNWIND(.fnend )
762ENDPROC(__pabt_usr)
763ENDPROC(ret_from_exception)
764
765 .align 5
766__fiq_usr:
767 usr_entry trace=0
768 kuser_cmpxchg_check
769 mov r0, sp @ struct pt_regs *regs
770 bl handle_fiq_as_nmi
771 get_thread_info tsk
772 restore_user_regs fast = 0, offset = 0
773 UNWIND(.fnend )
774ENDPROC(__fiq_usr)
775
776/*
777 * Register switch for ARMv3 and ARMv4 processors
778 * r0 = previous task_struct, r1 = previous thread_info, r2 = next thread_info
779 * previous and next are guaranteed not to be the same.
780 */
781ENTRY(__switch_to)
782 UNWIND(.fnstart )
783 UNWIND(.cantunwind )
784 add ip, r1, #TI_CPU_SAVE
785 ARM( stmia ip!, {r4 - sl, fp, sp, lr} ) @ Store most regs on stack
786 THUMB( stmia ip!, {r4 - sl, fp} ) @ Store most regs on stack
787 THUMB( str sp, [ip], #4 )
788 THUMB( str lr, [ip], #4 )
789 ldr r4, [r2, #TI_TP_VALUE]
790 ldr r5, [r2, #TI_TP_VALUE + 4]
791#ifdef CONFIG_CPU_USE_DOMAINS
792 mrc p15, 0, r6, c3, c0, 0 @ Get domain register
793 str r6, [r1, #TI_CPU_DOMAIN] @ Save old domain register
794 ldr r6, [r2, #TI_CPU_DOMAIN]
795#endif
796 switch_tls r1, r4, r5, r3, r7
797#if defined(CONFIG_CC_STACKPROTECTOR) && !defined(CONFIG_SMP)
798 ldr r7, [r2, #TI_TASK]
799 ldr r8, =__stack_chk_guard
800 ldr r7, [r7, #TSK_STACK_CANARY]
801#endif
802#ifdef CONFIG_CPU_USE_DOMAINS
803 mcr p15, 0, r6, c3, c0, 0 @ Set domain register
804#endif
805 mov r5, r0
806 add r4, r2, #TI_CPU_SAVE
807 ldr r0, =thread_notify_head
808 mov r1, #THREAD_NOTIFY_SWITCH
809 bl atomic_notifier_call_chain
810#if defined(CONFIG_CC_STACKPROTECTOR) && !defined(CONFIG_SMP)
811 str r7, [r8]
812#endif
813 THUMB( mov ip, r4 )
814 mov r0, r5
815 ARM( ldmia r4, {r4 - sl, fp, sp, pc} ) @ Load all regs saved previously
816 THUMB( ldmia ip!, {r4 - sl, fp} ) @ Load all regs saved previously
817 THUMB( ldr sp, [ip], #4 )
818 THUMB( ldr pc, [ip] )
819 UNWIND(.fnend )
820ENDPROC(__switch_to)
821
822 __INIT
823
824/*
825 * User helpers.
826 *
827 * Each segment is 32-byte aligned and will be moved to the top of the high
828 * vector page. New segments (if ever needed) must be added in front of
829 * existing ones. This mechanism should be used only for things that are
830 * really small and justified, and not be abused freely.
831 *
832 * See Documentation/arm/kernel_user_helpers.txt for formal definitions.
833 */
834 THUMB( .arm )
835
836 .macro usr_ret, reg
837#ifdef CONFIG_ARM_THUMB
838 bx \reg
839#else
840 ret \reg
841#endif
842 .endm
843
844 .macro kuser_pad, sym, size
845 .if (. - \sym) & 3
846 .rept 4 - (. - \sym) & 3
847 .byte 0
848 .endr
849 .endif
850 .rept (\size - (. - \sym)) / 4
851 .word 0xe7fddef1
852 .endr
853 .endm
854
855#ifdef CONFIG_KUSER_HELPERS
856 .align 5
857 .globl __kuser_helper_start
858__kuser_helper_start:
859
860/*
861 * Due to the length of some sequences, __kuser_cmpxchg64 spans 2 regular
862 * kuser "slots", therefore 0xffff0f80 is not used as a valid entry point.
863 */
864
865__kuser_cmpxchg64: @ 0xffff0f60
866
867#if defined(CONFIG_CPU_32v6K)
868
869 stmfd sp!, {r4, r5, r6, r7}
870 ldrd r4, r5, [r0] @ load old val
871 ldrd r6, r7, [r1] @ load new val
872 smp_dmb arm
8731: ldrexd r0, r1, [r2] @ load current val
874 eors r3, r0, r4 @ compare with oldval (1)
875 eoreqs r3, r1, r5 @ compare with oldval (2)
876 strexdeq r3, r6, r7, [r2] @ store newval if eq
877 teqeq r3, #1 @ success?
878 beq 1b @ if no then retry
879 smp_dmb arm
880 rsbs r0, r3, #0 @ set returned val and C flag
881 ldmfd sp!, {r4, r5, r6, r7}
882 usr_ret lr
883
884#elif !defined(CONFIG_SMP)
885
886#ifdef CONFIG_MMU
887
888 /*
889 * The only thing that can break atomicity in this cmpxchg64
890 * implementation is either an IRQ or a data abort exception
891 * causing another process/thread to be scheduled in the middle of
892 * the critical sequence. The same strategy as for cmpxchg is used.
893 */
894 stmfd sp!, {r4, r5, r6, lr}
895 ldmia r0, {r4, r5} @ load old val
896 ldmia r1, {r6, lr} @ load new val
8971: ldmia r2, {r0, r1} @ load current val
898 eors r3, r0, r4 @ compare with oldval (1)
899 eoreqs r3, r1, r5 @ compare with oldval (2)
9002: stmeqia r2, {r6, lr} @ store newval if eq
901 rsbs r0, r3, #0 @ set return val and C flag
902 ldmfd sp!, {r4, r5, r6, pc}
903
904 .text
905kuser_cmpxchg64_fixup:
906 @ Called from kuser_cmpxchg_fixup.
907 @ r4 = address of interrupted insn (must be preserved).
908 @ sp = saved regs. r7 and r8 are clobbered.
909 @ 1b = first critical insn, 2b = last critical insn.
910 @ If r4 >= 1b and r4 <= 2b then saved pc_usr is set to 1b.
911 mov r7, #0xffff0fff
912 sub r7, r7, #(0xffff0fff - (0xffff0f60 + (1b - __kuser_cmpxchg64)))
913 subs r8, r4, r7
914 rsbcss r8, r8, #(2b - 1b)
915 strcs r7, [sp, #S_PC]
916#if __LINUX_ARM_ARCH__ < 6
917 bcc kuser_cmpxchg32_fixup
918#endif
919 ret lr
920 .previous
921
922#else
923#warning "NPTL on non MMU needs fixing"
924 mov r0, #-1
925 adds r0, r0, #0
926 usr_ret lr
927#endif
928
929#else
930#error "incoherent kernel configuration"
931#endif
932
933 kuser_pad __kuser_cmpxchg64, 64
934
935__kuser_memory_barrier: @ 0xffff0fa0
936 smp_dmb arm
937 usr_ret lr
938
939 kuser_pad __kuser_memory_barrier, 32
940
941__kuser_cmpxchg: @ 0xffff0fc0
942
943#if __LINUX_ARM_ARCH__ < 6
944
945#ifdef CONFIG_MMU
946
947 /*
948 * The only thing that can break atomicity in this cmpxchg
949 * implementation is either an IRQ or a data abort exception
950 * causing another process/thread to be scheduled in the middle
951 * of the critical sequence. To prevent this, code is added to
952 * the IRQ and data abort exception handlers to set the pc back
953 * to the beginning of the critical section if it is found to be
954 * within that critical section (see kuser_cmpxchg_fixup).
955 */
9561: ldr r3, [r2] @ load current val
957 subs r3, r3, r0 @ compare with oldval
9582: streq r1, [r2] @ store newval if eq
959 rsbs r0, r3, #0 @ set return val and C flag
960 usr_ret lr
961
962 .text
963kuser_cmpxchg32_fixup:
964 @ Called from kuser_cmpxchg_check macro.
965 @ r4 = address of interrupted insn (must be preserved).
966 @ sp = saved regs. r7 and r8 are clobbered.
967 @ 1b = first critical insn, 2b = last critical insn.
968 @ If r4 >= 1b and r4 <= 2b then saved pc_usr is set to 1b.
969 mov r7, #0xffff0fff
970 sub r7, r7, #(0xffff0fff - (0xffff0fc0 + (1b - __kuser_cmpxchg)))
971 subs r8, r4, r7
972 rsbcss r8, r8, #(2b - 1b)
973 strcs r7, [sp, #S_PC]
974 ret lr
975 .previous
976
977#else
978#warning "NPTL on non MMU needs fixing"
979 mov r0, #-1
980 adds r0, r0, #0
981 usr_ret lr
982#endif
983
984#else
985
986 smp_dmb arm
9871: ldrex r3, [r2]
988 subs r3, r3, r0
989 strexeq r3, r1, [r2]
990 teqeq r3, #1
991 beq 1b
992 rsbs r0, r3, #0
993 /* beware -- each __kuser slot must be 8 instructions max */
994 ALT_SMP(b __kuser_memory_barrier)
995 ALT_UP(usr_ret lr)
996
997#endif
998
999 kuser_pad __kuser_cmpxchg, 32
1000
1001__kuser_get_tls: @ 0xffff0fe0
1002 ldr r0, [pc, #(16 - 8)] @ read TLS, set in kuser_get_tls_init
1003 usr_ret lr
1004 mrc p15, 0, r0, c13, c0, 3 @ 0xffff0fe8 hardware TLS code
1005 kuser_pad __kuser_get_tls, 16
1006 .rep 3
1007 .word 0 @ 0xffff0ff0 software TLS value, then
1008 .endr @ pad up to __kuser_helper_version
1009
1010__kuser_helper_version: @ 0xffff0ffc
1011 .word ((__kuser_helper_end - __kuser_helper_start) >> 5)
1012
1013 .globl __kuser_helper_end
1014__kuser_helper_end:
1015
1016#endif
1017
1018 THUMB( .thumb )
1019
1020/*
1021 * Vector stubs.
1022 *
1023 * This code is copied to 0xffff1000 so we can use branches in the
1024 * vectors, rather than ldr's. Note that this code must not exceed
1025 * a page size.
1026 *
1027 * Common stub entry macro:
1028 * Enter in IRQ mode, spsr = SVC/USR CPSR, lr = SVC/USR PC
1029 *
1030 * SP points to a minimal amount of processor-private memory, the address
1031 * of which is copied into r0 for the mode specific abort handler.
1032 */
1033 .macro vector_stub, name, mode, correction=0
1034 .align 5
1035
1036vector_\name:
1037 .if \correction
1038 sub lr, lr, #\correction
1039 .endif
1040
1041 @
1042 @ Save r0, lr_<exception> (parent PC) and spsr_<exception>
1043 @ (parent CPSR)
1044 @
1045 stmia sp, {r0, lr} @ save r0, lr
1046 mrs lr, spsr
1047 str lr, [sp, #8] @ save spsr
1048
1049 @
1050 @ Prepare for SVC32 mode. IRQs remain disabled.
1051 @
1052 mrs r0, cpsr
1053 eor r0, r0, #(\mode ^ SVC_MODE | PSR_ISETSTATE)
1054 msr spsr_cxsf, r0
1055
1056 @
1057 @ the branch table must immediately follow this code
1058 @
1059 and lr, lr, #0x0f
1060 THUMB( adr r0, 1f )
1061 THUMB( ldr lr, [r0, lr, lsl #2] )
1062 mov r0, sp
1063 ARM( ldr lr, [pc, lr, lsl #2] )
1064 movs pc, lr @ branch to handler in SVC mode
1065ENDPROC(vector_\name)
1066
1067 .align 2
1068 @ handler addresses follow this label
10691:
1070 .endm
1071
1072 .section .stubs, "ax", %progbits
1073 @ This must be the first word
1074 .word vector_swi
1075
1076vector_rst:
1077 ARM( swi SYS_ERROR0 )
1078 THUMB( svc #0 )
1079 THUMB( nop )
1080 b vector_und
1081
1082/*
1083 * Interrupt dispatcher
1084 */
1085 vector_stub irq, IRQ_MODE, 4
1086
1087 .long __irq_usr @ 0 (USR_26 / USR_32)
1088 .long __irq_invalid @ 1 (FIQ_26 / FIQ_32)
1089 .long __irq_invalid @ 2 (IRQ_26 / IRQ_32)
1090 .long __irq_svc @ 3 (SVC_26 / SVC_32)
1091 .long __irq_invalid @ 4
1092 .long __irq_invalid @ 5
1093 .long __irq_invalid @ 6
1094 .long __irq_invalid @ 7
1095 .long __irq_invalid @ 8
1096 .long __irq_invalid @ 9
1097 .long __irq_invalid @ a
1098 .long __irq_invalid @ b
1099 .long __irq_invalid @ c
1100 .long __irq_invalid @ d
1101 .long __irq_invalid @ e
1102 .long __irq_invalid @ f
1103
1104/*
1105 * Data abort dispatcher
1106 * Enter in ABT mode, spsr = USR CPSR, lr = USR PC
1107 */
1108 vector_stub dabt, ABT_MODE, 8
1109
1110 .long __dabt_usr @ 0 (USR_26 / USR_32)
1111 .long __dabt_invalid @ 1 (FIQ_26 / FIQ_32)
1112 .long __dabt_invalid @ 2 (IRQ_26 / IRQ_32)
1113 .long __dabt_svc @ 3 (SVC_26 / SVC_32)
1114 .long __dabt_invalid @ 4
1115 .long __dabt_invalid @ 5
1116 .long __dabt_invalid @ 6
1117 .long __dabt_invalid @ 7
1118 .long __dabt_invalid @ 8
1119 .long __dabt_invalid @ 9
1120 .long __dabt_invalid @ a
1121 .long __dabt_invalid @ b
1122 .long __dabt_invalid @ c
1123 .long __dabt_invalid @ d
1124 .long __dabt_invalid @ e
1125 .long __dabt_invalid @ f
1126
1127/*
1128 * Prefetch abort dispatcher
1129 * Enter in ABT mode, spsr = USR CPSR, lr = USR PC
1130 */
1131 vector_stub pabt, ABT_MODE, 4
1132
1133 .long __pabt_usr @ 0 (USR_26 / USR_32)
1134 .long __pabt_invalid @ 1 (FIQ_26 / FIQ_32)
1135 .long __pabt_invalid @ 2 (IRQ_26 / IRQ_32)
1136 .long __pabt_svc @ 3 (SVC_26 / SVC_32)
1137 .long __pabt_invalid @ 4
1138 .long __pabt_invalid @ 5
1139 .long __pabt_invalid @ 6
1140 .long __pabt_invalid @ 7
1141 .long __pabt_invalid @ 8
1142 .long __pabt_invalid @ 9
1143 .long __pabt_invalid @ a
1144 .long __pabt_invalid @ b
1145 .long __pabt_invalid @ c
1146 .long __pabt_invalid @ d
1147 .long __pabt_invalid @ e
1148 .long __pabt_invalid @ f
1149
1150/*
1151 * Undef instr entry dispatcher
1152 * Enter in UND mode, spsr = SVC/USR CPSR, lr = SVC/USR PC
1153 */
1154 vector_stub und, UND_MODE
1155
1156 .long __und_usr @ 0 (USR_26 / USR_32)
1157 .long __und_invalid @ 1 (FIQ_26 / FIQ_32)
1158 .long __und_invalid @ 2 (IRQ_26 / IRQ_32)
1159 .long __und_svc @ 3 (SVC_26 / SVC_32)
1160 .long __und_invalid @ 4
1161 .long __und_invalid @ 5
1162 .long __und_invalid @ 6
1163 .long __und_invalid @ 7
1164 .long __und_invalid @ 8
1165 .long __und_invalid @ 9
1166 .long __und_invalid @ a
1167 .long __und_invalid @ b
1168 .long __und_invalid @ c
1169 .long __und_invalid @ d
1170 .long __und_invalid @ e
1171 .long __und_invalid @ f
1172
1173 .align 5
1174
1175/*=============================================================================
1176 * Address exception handler
1177 *-----------------------------------------------------------------------------
1178 * These aren't too critical.
1179 * (they're not supposed to happen, and won't happen in 32-bit data mode).
1180 */
1181
1182vector_addrexcptn:
1183 b vector_addrexcptn
1184
1185/*=============================================================================
1186 * FIQ "NMI" handler
1187 *-----------------------------------------------------------------------------
1188 * Handle a FIQ using the SVC stack allowing FIQ act like NMI on x86
1189 * systems.
1190 */
1191 vector_stub fiq, FIQ_MODE, 4
1192
1193 .long __fiq_usr @ 0 (USR_26 / USR_32)
1194 .long __fiq_svc @ 1 (FIQ_26 / FIQ_32)
1195 .long __fiq_svc @ 2 (IRQ_26 / IRQ_32)
1196 .long __fiq_svc @ 3 (SVC_26 / SVC_32)
1197 .long __fiq_svc @ 4
1198 .long __fiq_svc @ 5
1199 .long __fiq_svc @ 6
1200 .long __fiq_abt @ 7
1201 .long __fiq_svc @ 8
1202 .long __fiq_svc @ 9
1203 .long __fiq_svc @ a
1204 .long __fiq_svc @ b
1205 .long __fiq_svc @ c
1206 .long __fiq_svc @ d
1207 .long __fiq_svc @ e
1208 .long __fiq_svc @ f
1209
1210 .globl vector_fiq
1211
1212 .section .vectors, "ax", %progbits
1213.L__vectors_start:
1214 W(b) vector_rst
1215 W(b) vector_und
1216 W(ldr) pc, .L__vectors_start + 0x1000
1217 W(b) vector_pabt
1218 W(b) vector_dabt
1219 W(b) vector_addrexcptn
1220 W(b) vector_irq
1221 W(b) vector_fiq
1222
1223 .data
1224
1225 .globl cr_alignment
1226cr_alignment:
1227 .space 4
1228
1229#ifdef CONFIG_MULTI_IRQ_HANDLER
1230 .globl handle_arch_irq
1231handle_arch_irq:
1232 .space 4
1233#endif