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gerrit-public.fairphone.software / kernel / msm-4.9 / refs/tags/FP3-REL-Q-3.A.0107 / . / arch / nios2 / kernel / entry.S
blob: 1e515ccd698e38f4a437b43ee6a97eb8c2aed987 [file] [log] [blame]
Ley Foon Tan82ed08d2014-11-06 15:19:38 +0800[diff] [blame]1/*
2 * linux/arch/nios2/kernel/entry.S
3 *
4 * Copyright (C) 2013-2014 Altera Corporation
5 * Copyright (C) 2009, Wind River Systems Inc
6 *
7 * Implemented by fredrik.markstrom@gmail.com and ivarholmqvist@gmail.com
8 *
9 * Copyright (C) 1999-2002, Greg Ungerer (gerg@snapgear.com)
10 * Copyright (C) 1998 D. Jeff Dionne <jeff@lineo.ca>,
11 * Kenneth Albanowski <kjahds@kjahds.com>,
12 * Copyright (C) 2000 Lineo Inc. (www.lineo.com)
13 * Copyright (C) 2004 Microtronix Datacom Ltd.
14 *
15 * This file is subject to the terms and conditions of the GNU General Public
16 * License. See the file "COPYING" in the main directory of this archive
17 * for more details.
18 *
19 * Linux/m68k support by Hamish Macdonald
20 *
21 * 68060 fixes by Jesper Skov
22 * ColdFire support by Greg Ungerer (gerg@snapgear.com)
23 * 5307 fixes by David W. Miller
24 * linux 2.4 support David McCullough <davidm@snapgear.com>
25 */
26
27#include <linux/sys.h>
28#include <linux/linkage.h>
29#include <asm/asm-offsets.h>
30#include <asm/asm-macros.h>
31#include <asm/thread_info.h>
32#include <asm/errno.h>
33#include <asm/setup.h>
34#include <asm/entry.h>
35#include <asm/unistd.h>
36#include <asm/processor.h>
37
38.macro GET_THREAD_INFO reg
39.if THREAD_SIZE & 0xffff0000
40 andhi \reg, sp, %hi(~(THREAD_SIZE-1))
41.else
42 addi \reg, r0, %lo(~(THREAD_SIZE-1))
43 and \reg, \reg, sp
44.endif
45.endm
46
47.macro kuser_cmpxchg_check
48 /*
49 * Make sure our user space atomic helper is restarted if it was
50 * interrupted in a critical region.
51 * ea-4 = address of interrupted insn (ea must be preserved).
52 * sp = saved regs.
53 * cmpxchg_ldw = first critical insn, cmpxchg_stw = last critical insn.
54 * If ea <= cmpxchg_stw and ea > cmpxchg_ldw then saved EA is set to
55 * cmpxchg_ldw + 4.
56 */
57 /* et = cmpxchg_stw + 4 */
58 movui et, (KUSER_BASE + 4 + (cmpxchg_stw - __kuser_helper_start))
59 bgtu ea, et, 1f
60
61 subi et, et, (cmpxchg_stw - cmpxchg_ldw) /* et = cmpxchg_ldw + 4 */
62 bltu ea, et, 1f
63 stw et, PT_EA(sp) /* fix up EA */
64 mov ea, et
651:
66.endm
67
68.section .rodata
69.align 4
70exception_table:
71 .word unhandled_exception /* 0 - Reset */
72 .word unhandled_exception /* 1 - Processor-only Reset */
73 .word external_interrupt /* 2 - Interrupt */
74 .word handle_trap /* 3 - Trap Instruction */
75
76 .word instruction_trap /* 4 - Unimplemented instruction */
77 .word handle_illegal /* 5 - Illegal instruction */
78 .word handle_unaligned /* 6 - Misaligned data access */
79 .word handle_unaligned /* 7 - Misaligned destination address */
80
81 .word handle_diverror /* 8 - Division error */
82 .word protection_exception_ba /* 9 - Supervisor-only instr. address */
83 .word protection_exception_instr /* 10 - Supervisor only instruction */
84 .word protection_exception_ba /* 11 - Supervisor only data address */
85
86 .word unhandled_exception /* 12 - Double TLB miss (data) */
87 .word protection_exception_pte /* 13 - TLB permission violation (x) */
88 .word protection_exception_pte /* 14 - TLB permission violation (r) */
89 .word protection_exception_pte /* 15 - TLB permission violation (w) */
90
91 .word unhandled_exception /* 16 - MPU region violation */
92
93trap_table:
94 .word handle_system_call /* 0 */
Ley Foon Tanbaa54ab2015-04-16 15:19:01 +0800[diff] [blame]95 .word handle_trap_1 /* 1 */
96 .word handle_trap_2 /* 2 */
97 .word handle_trap_3 /* 3 */
98 .word handle_trap_reserved /* 4 */
99 .word handle_trap_reserved /* 5 */
100 .word handle_trap_reserved /* 6 */
101 .word handle_trap_reserved /* 7 */
102 .word handle_trap_reserved /* 8 */
103 .word handle_trap_reserved /* 9 */
104 .word handle_trap_reserved /* 10 */
105 .word handle_trap_reserved /* 11 */
106 .word handle_trap_reserved /* 12 */
107 .word handle_trap_reserved /* 13 */
108 .word handle_trap_reserved /* 14 */
109 .word handle_trap_reserved /* 15 */
110 .word handle_trap_reserved /* 16 */
111 .word handle_trap_reserved /* 17 */
112 .word handle_trap_reserved /* 18 */
113 .word handle_trap_reserved /* 19 */
114 .word handle_trap_reserved /* 20 */
115 .word handle_trap_reserved /* 21 */
116 .word handle_trap_reserved /* 22 */
117 .word handle_trap_reserved /* 23 */
118 .word handle_trap_reserved /* 24 */
119 .word handle_trap_reserved /* 25 */
120 .word handle_trap_reserved /* 26 */
121 .word handle_trap_reserved /* 27 */
122 .word handle_trap_reserved /* 28 */
123 .word handle_trap_reserved /* 29 */
Ley Foon Tand16d2be2015-02-16 19:26:43 +0800[diff] [blame]124#ifdef CONFIG_KGDB
125 .word handle_kgdb_breakpoint /* 30 KGDB breakpoint */
126#else
127 .word instruction_trap /* 30 */
128#endif
Ley Foon Tan82ed08d2014-11-06 15:19:38 +0800[diff] [blame]129 .word handle_breakpoint /* 31 */
130
131.text
132.set noat
133.set nobreak
134
135ENTRY(inthandler)
136 SAVE_ALL
137
138 kuser_cmpxchg_check
139
140 /* Clear EH bit before we get a new excpetion in the kernel
141 * and after we have saved it to the exception frame. This is done
142 * whether it's trap, tlb-miss or interrupt. If we don't do this
143 * estatus is not updated the next exception.
144 */
145 rdctl r24, status
146 movi r9, %lo(~STATUS_EH)
147 and r24, r24, r9
148 wrctl status, r24
149
150 /* Read cause and vector and branch to the associated handler */
151 mov r4, sp
152 rdctl r5, exception
153 movia r9, exception_table
154 add r24, r9, r5
155 ldw r24, 0(r24)
156 jmp r24
157
158
159/***********************************************************************
160 * Handle traps
161 ***********************************************************************
162 */
163ENTRY(handle_trap)
Ley Foon Tan4a89c302015-04-10 11:10:08 +0800[diff] [blame]164 ldwio r24, -4(ea) /* instruction that caused the exception */
Ley Foon Tan82ed08d2014-11-06 15:19:38 +0800[diff] [blame]165 srli r24, r24, 4
166 andi r24, r24, 0x7c
167 movia r9,trap_table
168 add r24, r24, r9
169 ldw r24, 0(r24)
170 jmp r24
171
172
173/***********************************************************************
174 * Handle system calls
175 ***********************************************************************
176 */
177ENTRY(handle_system_call)
178 /* Enable interrupts */
179 rdctl r10, status
180 ori r10, r10, STATUS_PIE
181 wrctl status, r10
182
183 /* Reload registers destroyed by common code. */
184 ldw r4, PT_R4(sp)
185 ldw r5, PT_R5(sp)
186
187local_restart:
188 /* Check that the requested system call is within limits */
189 movui r1, __NR_syscalls
190 bgeu r2, r1, ret_invsyscall
191 slli r1, r2, 2
192 movhi r11, %hiadj(sys_call_table)
193 add r1, r1, r11
194 ldw r1, %lo(sys_call_table)(r1)
195 beq r1, r0, ret_invsyscall
196
197 /* Check if we are being traced */
198 GET_THREAD_INFO r11
199 ldw r11,TI_FLAGS(r11)
200 BTBNZ r11,r11,TIF_SYSCALL_TRACE,traced_system_call
201
202 /* Execute the system call */
203 callr r1
204
205 /* If the syscall returns a negative result:
206 * Set r7 to 1 to indicate error,
207 * Negate r2 to get a positive error code
208 * If the syscall returns zero or a positive value:
209 * Set r7 to 0.
210 * The sigreturn system calls will skip the code below by
211 * adding to register ra. To avoid destroying registers
212 */
213translate_rc_and_ret:
214 movi r1, 0
215 bge r2, zero, 3f
216 sub r2, zero, r2
217 movi r1, 1
2183:
219 stw r2, PT_R2(sp)
220 stw r1, PT_R7(sp)
221end_translate_rc_and_ret:
222
223ret_from_exception:
224 ldw r1, PT_ESTATUS(sp)
225 /* if so, skip resched, signals */
226 TSTBNZ r1, r1, ESTATUS_EU, Luser_return
227
228restore_all:
229 rdctl r10, status /* disable intrs */
230 andi r10, r10, %lo(~STATUS_PIE)
231 wrctl status, r10
232 RESTORE_ALL
233 eret
234
235 /* If the syscall number was invalid return ENOSYS */
236ret_invsyscall:
237 movi r2, -ENOSYS
238 br translate_rc_and_ret
239
240 /* This implements the same as above, except it calls
241 * do_syscall_trace_enter and do_syscall_trace_exit before and after the
242 * syscall in order for utilities like strace and gdb to work.
243 */
244traced_system_call:
245 SAVE_SWITCH_STACK
246 call do_syscall_trace_enter
247 RESTORE_SWITCH_STACK
248
249 /* Create system call register arguments. The 5th and 6th
250 arguments on stack are already in place at the beginning
251 of pt_regs. */
252 ldw r2, PT_R2(sp)
253 ldw r4, PT_R4(sp)
254 ldw r5, PT_R5(sp)
255 ldw r6, PT_R6(sp)
256 ldw r7, PT_R7(sp)
257
258 /* Fetch the syscall function, we don't need to check the boundaries
259 * since this is already done.
260 */
261 slli r1, r2, 2
262 movhi r11,%hiadj(sys_call_table)
263 add r1, r1, r11
264 ldw r1, %lo(sys_call_table)(r1)
265
266 callr r1
267
268 /* If the syscall returns a negative result:
269 * Set r7 to 1 to indicate error,
270 * Negate r2 to get a positive error code
271 * If the syscall returns zero or a positive value:
272 * Set r7 to 0.
273 * The sigreturn system calls will skip the code below by
274 * adding to register ra. To avoid destroying registers
275 */
276translate_rc_and_ret2:
277 movi r1, 0
278 bge r2, zero, 4f
279 sub r2, zero, r2
280 movi r1, 1
2814:
282 stw r2, PT_R2(sp)
283 stw r1, PT_R7(sp)
284end_translate_rc_and_ret2:
285 SAVE_SWITCH_STACK
286 call do_syscall_trace_exit
287 RESTORE_SWITCH_STACK
288 br ret_from_exception
289
290Luser_return:
291 GET_THREAD_INFO r11 /* get thread_info pointer */
292 ldw r10, TI_FLAGS(r11) /* get thread_info->flags */
293 ANDI32 r11, r10, _TIF_WORK_MASK
294 beq r11, r0, restore_all /* Nothing to do */
295 BTBZ r1, r10, TIF_NEED_RESCHED, Lsignal_return
296
297 /* Reschedule work */
298 call schedule
299 br ret_from_exception
300
301Lsignal_return:
302 ANDI32 r1, r10, _TIF_SIGPENDING | _TIF_NOTIFY_RESUME
303 beq r1, r0, restore_all
304 mov r4, sp /* pt_regs */
305 SAVE_SWITCH_STACK
306 call do_notify_resume
307 beq r2, r0, no_work_pending
308 RESTORE_SWITCH_STACK
309 /* prepare restart syscall here without leaving kernel */
310 ldw r2, PT_R2(sp) /* reload syscall number in r2 */
311 ldw r4, PT_R4(sp) /* reload syscall arguments r4-r9 */
312 ldw r5, PT_R5(sp)
313 ldw r6, PT_R6(sp)
314 ldw r7, PT_R7(sp)
315 ldw r8, PT_R8(sp)
316 ldw r9, PT_R9(sp)
317 br local_restart /* restart syscall */
318
319no_work_pending:
320 RESTORE_SWITCH_STACK
321 br ret_from_exception
322
323/***********************************************************************
324 * Handle external interrupts.
325 ***********************************************************************
326 */
327/*
328 * This is the generic interrupt handler (for all hardware interrupt
329 * sources). It figures out the vector number and calls the appropriate
330 * interrupt service routine directly.
331 */
332external_interrupt:
333 rdctl r12, ipending
334 rdctl r9, ienable
335 and r12, r12, r9
336 /* skip if no interrupt is pending */
337 beq r12, r0, ret_from_interrupt
338
339 movi r24, -1
340 stw r24, PT_ORIG_R2(sp)
341
342 /*
343 * Process an external hardware interrupt.
344 */
345
346 addi ea, ea, -4 /* re-issue the interrupted instruction */
347 stw ea, PT_EA(sp)
3482: movi r4, %lo(-1) /* Start from bit position 0,
349 highest priority */
350 /* This is the IRQ # for handler call */
3511: andi r10, r12, 1 /* Isolate bit we are interested in */
352 srli r12, r12, 1 /* shift count is costly without hardware
353 multiplier */
354 addi r4, r4, 1
355 beq r10, r0, 1b
356 mov r5, sp /* Setup pt_regs pointer for handler call */
357 call do_IRQ
358 rdctl r12, ipending /* check again if irq still pending */
359 rdctl r9, ienable /* Isolate possible interrupts */
360 and r12, r12, r9
361 bne r12, r0, 2b
362 /* br ret_from_interrupt */ /* fall through to ret_from_interrupt */
363
364ENTRY(ret_from_interrupt)
365 ldw r1, PT_ESTATUS(sp) /* check if returning to kernel */
366 TSTBNZ r1, r1, ESTATUS_EU, Luser_return
367
368#ifdef CONFIG_PREEMPT
369 GET_THREAD_INFO r1
370 ldw r4, TI_PREEMPT_COUNT(r1)
371 bne r4, r0, restore_all
Ley Foon Tan82ed08d2014-11-06 15:19:38 +0800[diff] [blame]372 ldw r4, TI_FLAGS(r1) /* ? Need resched set */
373 BTBZ r10, r4, TIF_NEED_RESCHED, restore_all
374 ldw r4, PT_ESTATUS(sp) /* ? Interrupts off */
375 andi r10, r4, ESTATUS_EPIE
376 beq r10, r0, restore_all
Tobias Klauser1b0f4492014-12-31 10:53:11 +0800[diff] [blame]377 call preempt_schedule_irq
Ley Foon Tan82ed08d2014-11-06 15:19:38 +0800[diff] [blame]378#endif
Tobias Klauser1b0f4492014-12-31 10:53:11 +0800[diff] [blame]379 br restore_all
Ley Foon Tan82ed08d2014-11-06 15:19:38 +0800[diff] [blame]380
381/***********************************************************************
382 * A few syscall wrappers
383 ***********************************************************************
384 */
385/*
386 * int clone(unsigned long clone_flags, unsigned long newsp,
387 * int __user * parent_tidptr, int __user * child_tidptr,
388 * int tls_val)
389 */
390ENTRY(sys_clone)
391 SAVE_SWITCH_STACK
392 addi sp, sp, -4
393 stw r7, 0(sp) /* Pass 5th arg thru stack */
394 mov r7, r6 /* 4th arg is 3rd of clone() */
395 mov r6, zero /* 3rd arg always 0 */
396 call do_fork
397 addi sp, sp, 4
398 RESTORE_SWITCH_STACK
399 ret
400
401ENTRY(sys_rt_sigreturn)
402 SAVE_SWITCH_STACK
403 mov r4, sp
404 call do_rt_sigreturn
405 RESTORE_SWITCH_STACK
406 addi ra, ra, (end_translate_rc_and_ret - translate_rc_and_ret)
407 ret
408
409/***********************************************************************
410 * A few other wrappers and stubs
411 ***********************************************************************
412 */
413protection_exception_pte:
414 rdctl r6, pteaddr
415 slli r6, r6, 10
416 call do_page_fault
417 br ret_from_exception
418
419protection_exception_ba:
420 rdctl r6, badaddr
421 call do_page_fault
422 br ret_from_exception
423
424protection_exception_instr:
425 call handle_supervisor_instr
426 br ret_from_exception
427
428handle_breakpoint:
429 call breakpoint_c
430 br ret_from_exception
431
432#ifdef CONFIG_NIOS2_ALIGNMENT_TRAP
433handle_unaligned:
434 SAVE_SWITCH_STACK
435 call handle_unaligned_c
436 RESTORE_SWITCH_STACK
437 br ret_from_exception
438#else
439handle_unaligned:
440 call handle_unaligned_c
441 br ret_from_exception
442#endif
443
444handle_illegal:
445 call handle_illegal_c
446 br ret_from_exception
447
448handle_diverror:
449 call handle_diverror_c
450 br ret_from_exception
451
Ley Foon Tand16d2be2015-02-16 19:26:43 +0800[diff] [blame]452#ifdef CONFIG_KGDB
453handle_kgdb_breakpoint:
454 call kgdb_breakpoint_c
455 br ret_from_exception
456#endif
457
Ley Foon Tanbaa54ab2015-04-16 15:19:01 +0800[diff] [blame]458handle_trap_1:
459 call handle_trap_1_c
460 br ret_from_exception
461
462handle_trap_2:
463 call handle_trap_2_c
464 br ret_from_exception
465
466handle_trap_3:
467handle_trap_reserved:
468 call handle_trap_3_c
469 br ret_from_exception
470
Ley Foon Tan82ed08d2014-11-06 15:19:38 +0800[diff] [blame]471/*
472 * Beware - when entering resume, prev (the current task) is
473 * in r4, next (the new task) is in r5, don't change these
474 * registers.
475 */
476ENTRY(resume)
477
478 rdctl r7, status /* save thread status reg */
479 stw r7, TASK_THREAD + THREAD_KPSR(r4)
480
481 andi r7, r7, %lo(~STATUS_PIE) /* disable interrupts */
482 wrctl status, r7
483
484 SAVE_SWITCH_STACK
485 stw sp, TASK_THREAD + THREAD_KSP(r4)/* save kernel stack pointer */
486 ldw sp, TASK_THREAD + THREAD_KSP(r5)/* restore new thread stack */
487 movia r24, _current_thread /* save thread */
488 GET_THREAD_INFO r1
489 stw r1, 0(r24)
490 RESTORE_SWITCH_STACK
491
492 ldw r7, TASK_THREAD + THREAD_KPSR(r5)/* restore thread status reg */
493 wrctl status, r7
494 ret
495
496ENTRY(ret_from_fork)
497 call schedule_tail
498 br ret_from_exception
499
500ENTRY(ret_from_kernel_thread)
501 call schedule_tail
502 mov r4,r17 /* arg */
503 callr r16 /* function */
504 br ret_from_exception
505
506/*
507 * Kernel user helpers.
508 *
509 * Each segment is 64-byte aligned and will be mapped to the <User space>.
510 * New segments (if ever needed) must be added after the existing ones.
511 * This mechanism should be used only for things that are really small and
512 * justified, and not be abused freely.
513 *
514 */
515
516 /* Filling pads with undefined instructions. */
517.macro kuser_pad sym size
518 .if ((. - \sym) & 3)
519 .rept (4 - (. - \sym) & 3)
520 .byte 0
521 .endr
522 .endif
523 .rept ((\size - (. - \sym)) / 4)
524 .word 0xdeadbeef
525 .endr
526.endm
527
528 .align 6
529 .globl __kuser_helper_start
530__kuser_helper_start:
531
532__kuser_helper_version: /* @ 0x1000 */
533 .word ((__kuser_helper_end - __kuser_helper_start) >> 6)
534
535__kuser_cmpxchg: /* @ 0x1004 */
536 /*
537 * r4 pointer to exchange variable
538 * r5 old value
539 * r6 new value
540 */
541cmpxchg_ldw:
542 ldw r2, 0(r4) /* load current value */
543 sub r2, r2, r5 /* compare with old value */
544 bne r2, zero, cmpxchg_ret
545
546 /* We had a match, store the new value */
547cmpxchg_stw:
548 stw r6, 0(r4)
549cmpxchg_ret:
550 ret
551
552 kuser_pad __kuser_cmpxchg, 64
553
554 .globl __kuser_sigtramp
555__kuser_sigtramp:
556 movi r2, __NR_rt_sigreturn
557 trap
558
559 kuser_pad __kuser_sigtramp, 64
560
561 .globl __kuser_helper_end
562__kuser_helper_end: