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1/*
2 * OpenRISC entry.S
3 *
4 * Linux architectural port borrowing liberally from similar works of
5 * others. All original copyrights apply as per the original source
6 * declaration.
7 *
8 * Modifications for the OpenRISC architecture:
9 * Copyright (C) 2003 Matjaz Breskvar <phoenix@bsemi.com>
10 * Copyright (C) 2005 Gyorgy Jeney <nog@bsemi.com>
11 * Copyright (C) 2010-2011 Jonas Bonn <jonas@southpole.se>
12 *
13 * This program is free software; you can redistribute it and/or
14 * modify it under the terms of the GNU General Public License
15 * as published by the Free Software Foundation; either version
16 * 2 of the License, or (at your option) any later version.
17 */
18
19#include <linux/linkage.h>
20
21#include <asm/processor.h>
22#include <asm/unistd.h>
23#include <asm/thread_info.h>
24#include <asm/errno.h>
25#include <asm/spr_defs.h>
26#include <asm/page.h>
27#include <asm/mmu.h>
28#include <asm/pgtable.h>
29#include <asm/asm-offsets.h>
30
31#define DISABLE_INTERRUPTS(t1,t2) \
32 l.mfspr t2,r0,SPR_SR ;\
33 l.movhi t1,hi(~(SPR_SR_IEE|SPR_SR_TEE)) ;\
34 l.ori t1,t1,lo(~(SPR_SR_IEE|SPR_SR_TEE)) ;\
35 l.and t2,t2,t1 ;\
36 l.mtspr r0,t2,SPR_SR
37
38#define ENABLE_INTERRUPTS(t1) \
39 l.mfspr t1,r0,SPR_SR ;\
40 l.ori t1,t1,lo(SPR_SR_IEE|SPR_SR_TEE) ;\
41 l.mtspr r0,t1,SPR_SR
42
43/* =========================================================[ macros ]=== */
44
45/*
46 * We need to disable interrupts at beginning of RESTORE_ALL
47 * since interrupt might come in after we've loaded EPC return address
48 * and overwrite EPC with address somewhere in RESTORE_ALL
49 * which is of course wrong!
50 */
51
52#define RESTORE_ALL \
53 DISABLE_INTERRUPTS(r3,r4) ;\
54 l.lwz r3,PT_PC(r1) ;\
55 l.mtspr r0,r3,SPR_EPCR_BASE ;\
56 l.lwz r3,PT_SR(r1) ;\
57 l.mtspr r0,r3,SPR_ESR_BASE ;\
58 l.lwz r2,PT_GPR2(r1) ;\
59 l.lwz r3,PT_GPR3(r1) ;\
60 l.lwz r4,PT_GPR4(r1) ;\
61 l.lwz r5,PT_GPR5(r1) ;\
62 l.lwz r6,PT_GPR6(r1) ;\
63 l.lwz r7,PT_GPR7(r1) ;\
64 l.lwz r8,PT_GPR8(r1) ;\
65 l.lwz r9,PT_GPR9(r1) ;\
66 l.lwz r10,PT_GPR10(r1) ;\
67 l.lwz r11,PT_GPR11(r1) ;\
68 l.lwz r12,PT_GPR12(r1) ;\
69 l.lwz r13,PT_GPR13(r1) ;\
70 l.lwz r14,PT_GPR14(r1) ;\
71 l.lwz r15,PT_GPR15(r1) ;\
72 l.lwz r16,PT_GPR16(r1) ;\
73 l.lwz r17,PT_GPR17(r1) ;\
74 l.lwz r18,PT_GPR18(r1) ;\
75 l.lwz r19,PT_GPR19(r1) ;\
76 l.lwz r20,PT_GPR20(r1) ;\
77 l.lwz r21,PT_GPR21(r1) ;\
78 l.lwz r22,PT_GPR22(r1) ;\
79 l.lwz r23,PT_GPR23(r1) ;\
80 l.lwz r24,PT_GPR24(r1) ;\
81 l.lwz r25,PT_GPR25(r1) ;\
82 l.lwz r26,PT_GPR26(r1) ;\
83 l.lwz r27,PT_GPR27(r1) ;\
84 l.lwz r28,PT_GPR28(r1) ;\
85 l.lwz r29,PT_GPR29(r1) ;\
86 l.lwz r30,PT_GPR30(r1) ;\
87 l.lwz r31,PT_GPR31(r1) ;\
88 l.lwz r1,PT_SP(r1) ;\
89 l.rfe
90
91
92#define EXCEPTION_ENTRY(handler) \
93 .global handler ;\
94handler: ;\
95 /* r1, EPCR, ESR a already saved */ ;\
96 l.sw PT_GPR2(r1),r2 ;\
97 l.sw PT_GPR3(r1),r3 ;\
98 l.sw PT_ORIG_GPR11(r1),r11 ;\
99 /* r4 already save */ ;\
100 l.sw PT_GPR5(r1),r5 ;\
101 l.sw PT_GPR6(r1),r6 ;\
102 l.sw PT_GPR7(r1),r7 ;\
103 l.sw PT_GPR8(r1),r8 ;\
104 l.sw PT_GPR9(r1),r9 ;\
105 /* r10 already saved */ ;\
106 l.sw PT_GPR11(r1),r11 ;\
107 /* r12 already saved */ ;\
108 l.sw PT_GPR13(r1),r13 ;\
109 l.sw PT_GPR14(r1),r14 ;\
110 l.sw PT_GPR15(r1),r15 ;\
111 l.sw PT_GPR16(r1),r16 ;\
112 l.sw PT_GPR17(r1),r17 ;\
113 l.sw PT_GPR18(r1),r18 ;\
114 l.sw PT_GPR19(r1),r19 ;\
115 l.sw PT_GPR20(r1),r20 ;\
116 l.sw PT_GPR21(r1),r21 ;\
117 l.sw PT_GPR22(r1),r22 ;\
118 l.sw PT_GPR23(r1),r23 ;\
119 l.sw PT_GPR24(r1),r24 ;\
120 l.sw PT_GPR25(r1),r25 ;\
121 l.sw PT_GPR26(r1),r26 ;\
122 l.sw PT_GPR27(r1),r27 ;\
123 l.sw PT_GPR28(r1),r28 ;\
124 l.sw PT_GPR29(r1),r29 ;\
125 /* r30 already save */ ;\
126/* l.sw PT_GPR30(r1),r30*/ ;\
127 l.sw PT_GPR31(r1),r31 ;\
128 l.sw PT_SYSCALLNO(r1),r0
129
130#define UNHANDLED_EXCEPTION(handler,vector) \
131 .global handler ;\
132handler: ;\
133 /* r1, EPCR, ESR already saved */ ;\
134 l.sw PT_GPR2(r1),r2 ;\
135 l.sw PT_GPR3(r1),r3 ;\
136 l.sw PT_ORIG_GPR11(r1),r11 ;\
137 l.sw PT_GPR5(r1),r5 ;\
138 l.sw PT_GPR6(r1),r6 ;\
139 l.sw PT_GPR7(r1),r7 ;\
140 l.sw PT_GPR8(r1),r8 ;\
141 l.sw PT_GPR9(r1),r9 ;\
142 /* r10 already saved */ ;\
143 l.sw PT_GPR11(r1),r11 ;\
144 /* r12 already saved */ ;\
145 l.sw PT_GPR13(r1),r13 ;\
146 l.sw PT_GPR14(r1),r14 ;\
147 l.sw PT_GPR15(r1),r15 ;\
148 l.sw PT_GPR16(r1),r16 ;\
149 l.sw PT_GPR17(r1),r17 ;\
150 l.sw PT_GPR18(r1),r18 ;\
151 l.sw PT_GPR19(r1),r19 ;\
152 l.sw PT_GPR20(r1),r20 ;\
153 l.sw PT_GPR21(r1),r21 ;\
154 l.sw PT_GPR22(r1),r22 ;\
155 l.sw PT_GPR23(r1),r23 ;\
156 l.sw PT_GPR24(r1),r24 ;\
157 l.sw PT_GPR25(r1),r25 ;\
158 l.sw PT_GPR26(r1),r26 ;\
159 l.sw PT_GPR27(r1),r27 ;\
160 l.sw PT_GPR28(r1),r28 ;\
161 l.sw PT_GPR29(r1),r29 ;\
162 /* r31 already saved */ ;\
163 l.sw PT_GPR30(r1),r30 ;\
164/* l.sw PT_GPR31(r1),r31 */ ;\
165 l.sw PT_SYSCALLNO(r1),r0 ;\
166 l.addi r3,r1,0 ;\
167 /* r4 is exception EA */ ;\
168 l.addi r5,r0,vector ;\
169 l.jal unhandled_exception ;\
170 l.nop ;\
171 l.j _ret_from_exception ;\
172 l.nop
173
174/*
175 * NOTE: one should never assume that SPR_EPC, SPR_ESR, SPR_EEAR
176 * contain the same values as when exception we're handling
177 * occured. in fact they never do. if you need them use
178 * values saved on stack (for SPR_EPC, SPR_ESR) or content
179 * of r4 (for SPR_EEAR). for details look at EXCEPTION_HANDLE()
180 * in 'arch/or32/kernel/head.S'
181 */
182
183/* =====================================================[ exceptions] === */
184
185/* ---[ 0x100: RESET exception ]----------------------------------------- */
186
187EXCEPTION_ENTRY(_tng_kernel_start)
188 l.jal _start
189 l.andi r0,r0,0
190
191/* ---[ 0x200: BUS exception ]------------------------------------------- */
192
193EXCEPTION_ENTRY(_bus_fault_handler)
194 /* r4: EA of fault (set by EXCEPTION_HANDLE) */
195 l.jal do_bus_fault
196 l.addi r3,r1,0 /* pt_regs */
197
198 l.j _ret_from_exception
199 l.nop
200
201/* ---[ 0x300: Data Page Fault exception ]------------------------------- */
202
203EXCEPTION_ENTRY(_data_page_fault_handler)
204 /* set up parameters for do_page_fault */
205 l.addi r3,r1,0 // pt_regs
206 /* r4 set be EXCEPTION_HANDLE */ // effective address of fault
207 l.ori r5,r0,0x300 // exception vector
208
209 /*
210 * __PHX__: TODO
211 *
212 * all this can be written much simpler. look at
213 * DTLB miss handler in the CONFIG_GUARD_PROTECTED_CORE part
214 */
215#ifdef CONFIG_OPENRISC_NO_SPR_SR_DSX
216 l.lwz r6,PT_PC(r3) // address of an offending insn
217 l.lwz r6,0(r6) // instruction that caused pf
218
219 l.srli r6,r6,26 // check opcode for jump insn
220 l.sfeqi r6,0 // l.j
221 l.bf 8f
222 l.sfeqi r6,1 // l.jal
223 l.bf 8f
224 l.sfeqi r6,3 // l.bnf
225 l.bf 8f
226 l.sfeqi r6,4 // l.bf
227 l.bf 8f
228 l.sfeqi r6,0x11 // l.jr
229 l.bf 8f
230 l.sfeqi r6,0x12 // l.jalr
231 l.bf 8f
232
233 l.nop
234
235 l.j 9f
236 l.nop
2378:
238
239 l.lwz r6,PT_PC(r3) // address of an offending insn
240 l.addi r6,r6,4
241 l.lwz r6,0(r6) // instruction that caused pf
242 l.srli r6,r6,26 // get opcode
2439:
244
245#else
246
247 l.mfspr r6,r0,SPR_SR // SR
248// l.lwz r6,PT_SR(r3) // ESR
249 l.andi r6,r6,SPR_SR_DSX // check for delay slot exception
250 l.sfeqi r6,0x1 // exception happened in delay slot
251 l.bnf 7f
252 l.lwz r6,PT_PC(r3) // address of an offending insn
253
254 l.addi r6,r6,4 // offending insn is in delay slot
2557:
256 l.lwz r6,0(r6) // instruction that caused pf
257 l.srli r6,r6,26 // check opcode for write access
258#endif
259
260 l.sfgeui r6,0x34 // check opcode for write access
261 l.bnf 1f
262 l.sfleui r6,0x37
263 l.bnf 1f
264 l.ori r6,r0,0x1 // write access
265 l.j 2f
266 l.nop
2671: l.ori r6,r0,0x0 // !write access
2682:
269
270 /* call fault.c handler in or32/mm/fault.c */
271 l.jal do_page_fault
272 l.nop
273 l.j _ret_from_exception
274 l.nop
275
276/* ---[ 0x400: Insn Page Fault exception ]------------------------------- */
277
278EXCEPTION_ENTRY(_insn_page_fault_handler)
279 /* set up parameters for do_page_fault */
280 l.addi r3,r1,0 // pt_regs
281 /* r4 set be EXCEPTION_HANDLE */ // effective address of fault
282 l.ori r5,r0,0x400 // exception vector
283 l.ori r6,r0,0x0 // !write access
284
285 /* call fault.c handler in or32/mm/fault.c */
286 l.jal do_page_fault
287 l.nop
288 l.j _ret_from_exception
289 l.nop
290
291
292/* ---[ 0x500: Timer exception ]----------------------------------------- */
293
294EXCEPTION_ENTRY(_timer_handler)
295 l.jal timer_interrupt
296 l.addi r3,r1,0 /* pt_regs */
297
298 l.j _ret_from_intr
299 l.nop
300
301/* ---[ 0x600: Aligment exception ]-------------------------------------- */
302
303EXCEPTION_ENTRY(_alignment_handler)
304 /* r4: EA of fault (set by EXCEPTION_HANDLE) */
305 l.jal do_unaligned_access
306 l.addi r3,r1,0 /* pt_regs */
307
308 l.j _ret_from_exception
309 l.nop
310
311#if 0
312EXCEPTION_ENTRY(_aligment_handler)
313// l.mfspr r2,r0,SPR_EEAR_BASE /* Load the efective addres */
314 l.addi r2,r4,0
315// l.mfspr r5,r0,SPR_EPCR_BASE /* Load the insn address */
316 l.lwz r5,PT_PC(r1)
317
318 l.lwz r3,0(r5) /* Load insn */
319 l.srli r4,r3,26 /* Shift left to get the insn opcode */
320
321 l.sfeqi r4,0x00 /* Check if the load/store insn is in delay slot */
322 l.bf jmp
323 l.sfeqi r4,0x01
324 l.bf jmp
325 l.sfeqi r4,0x03
326 l.bf jmp
327 l.sfeqi r4,0x04
328 l.bf jmp
329 l.sfeqi r4,0x11
330 l.bf jr
331 l.sfeqi r4,0x12
332 l.bf jr
333 l.nop
334 l.j 1f
335 l.addi r5,r5,4 /* Increment PC to get return insn address */
336
337jmp:
338 l.slli r4,r3,6 /* Get the signed extended jump length */
339 l.srai r4,r4,4
340
341 l.lwz r3,4(r5) /* Load the real load/store insn */
342
343 l.add r5,r5,r4 /* Calculate jump target address */
344
345 l.j 1f
346 l.srli r4,r3,26 /* Shift left to get the insn opcode */
347
348jr:
349 l.slli r4,r3,9 /* Shift to get the reg nb */
350 l.andi r4,r4,0x7c
351
352 l.lwz r3,4(r5) /* Load the real load/store insn */
353
354 l.add r4,r4,r1 /* Load the jump register value from the stack */
355 l.lwz r5,0(r4)
356
357 l.srli r4,r3,26 /* Shift left to get the insn opcode */
358
359
3601:
361// l.mtspr r0,r5,SPR_EPCR_BASE
362 l.sw PT_PC(r1),r5
363
364 l.sfeqi r4,0x26
365 l.bf lhs
366 l.sfeqi r4,0x25
367 l.bf lhz
368 l.sfeqi r4,0x22
369 l.bf lws
370 l.sfeqi r4,0x21
371 l.bf lwz
372 l.sfeqi r4,0x37
373 l.bf sh
374 l.sfeqi r4,0x35
375 l.bf sw
376 l.nop
377
3781: l.j 1b /* I don't know what to do */
379 l.nop
380
381lhs: l.lbs r5,0(r2)
382 l.slli r5,r5,8
383 l.lbz r6,1(r2)
384 l.or r5,r5,r6
385 l.srli r4,r3,19
386 l.andi r4,r4,0x7c
387 l.add r4,r4,r1
388 l.j align_end
389 l.sw 0(r4),r5
390
391lhz: l.lbz r5,0(r2)
392 l.slli r5,r5,8
393 l.lbz r6,1(r2)
394 l.or r5,r5,r6
395 l.srli r4,r3,19
396 l.andi r4,r4,0x7c
397 l.add r4,r4,r1
398 l.j align_end
399 l.sw 0(r4),r5
400
401lws: l.lbs r5,0(r2)
402 l.slli r5,r5,24
403 l.lbz r6,1(r2)
404 l.slli r6,r6,16
405 l.or r5,r5,r6
406 l.lbz r6,2(r2)
407 l.slli r6,r6,8
408 l.or r5,r5,r6
409 l.lbz r6,3(r2)
410 l.or r5,r5,r6
411 l.srli r4,r3,19
412 l.andi r4,r4,0x7c
413 l.add r4,r4,r1
414 l.j align_end
415 l.sw 0(r4),r5
416
417lwz: l.lbz r5,0(r2)
418 l.slli r5,r5,24
419 l.lbz r6,1(r2)
420 l.slli r6,r6,16
421 l.or r5,r5,r6
422 l.lbz r6,2(r2)
423 l.slli r6,r6,8
424 l.or r5,r5,r6
425 l.lbz r6,3(r2)
426 l.or r5,r5,r6
427 l.srli r4,r3,19
428 l.andi r4,r4,0x7c
429 l.add r4,r4,r1
430 l.j align_end
431 l.sw 0(r4),r5
432
433sh:
434 l.srli r4,r3,9
435 l.andi r4,r4,0x7c
436 l.add r4,r4,r1
437 l.lwz r5,0(r4)
438 l.sb 1(r2),r5
439 l.srli r5,r5,8
440 l.j align_end
441 l.sb 0(r2),r5
442
443sw:
444 l.srli r4,r3,9
445 l.andi r4,r4,0x7c
446 l.add r4,r4,r1
447 l.lwz r5,0(r4)
448 l.sb 3(r2),r5
449 l.srli r5,r5,8
450 l.sb 2(r2),r5
451 l.srli r5,r5,8
452 l.sb 1(r2),r5
453 l.srli r5,r5,8
454 l.j align_end
455 l.sb 0(r2),r5
456
457align_end:
458 l.j _ret_from_intr
459 l.nop
460#endif
461
462/* ---[ 0x700: Illegal insn exception ]---------------------------------- */
463
464EXCEPTION_ENTRY(_illegal_instruction_handler)
465 /* r4: EA of fault (set by EXCEPTION_HANDLE) */
466 l.jal do_illegal_instruction
467 l.addi r3,r1,0 /* pt_regs */
468
469 l.j _ret_from_exception
470 l.nop
471
472/* ---[ 0x800: External interrupt exception ]---------------------------- */
473
474EXCEPTION_ENTRY(_external_irq_handler)
475#ifdef CONFIG_OPENRISC_ESR_EXCEPTION_BUG_CHECK
476 l.lwz r4,PT_SR(r1) // were interrupts enabled ?
477 l.andi r4,r4,SPR_SR_IEE
478 l.sfeqi r4,0
479 l.bnf 1f // ext irq enabled, all ok.
480 l.nop
481
482 l.addi r1,r1,-0x8
483 l.movhi r3,hi(42f)
484 l.ori r3,r3,lo(42f)
485 l.sw 0x0(r1),r3
486 l.jal printk
487 l.sw 0x4(r1),r4
488 l.addi r1,r1,0x8
489
490 .section .rodata, "a"
49142:
492 .string "\n\rESR interrupt bug: in _external_irq_handler (ESR %x)\n\r"
493 .align 4
494 .previous
495
496 l.ori r4,r4,SPR_SR_IEE // fix the bug
497// l.sw PT_SR(r1),r4
4981:
499#endif
500 l.addi r3,r1,0
501 l.movhi r8,hi(do_IRQ)
502 l.ori r8,r8,lo(do_IRQ)
503 l.jalr r8
504 l.nop
505 l.j _ret_from_intr
506 l.nop
507
508/* ---[ 0x900: DTLB miss exception ]------------------------------------- */
509
510
511/* ---[ 0xa00: ITLB miss exception ]------------------------------------- */
512
513
514/* ---[ 0xb00: Range exception ]----------------------------------------- */
515
516UNHANDLED_EXCEPTION(_vector_0xb00,0xb00)
517
518/* ---[ 0xc00: Syscall exception ]--------------------------------------- */
519
520/*
521 * Syscalls are a special type of exception in that they are
522 * _explicitly_ invoked by userspace and can therefore be
523 * held to conform to the same ABI as normal functions with
524 * respect to whether registers are preserved across the call
525 * or not.
526 */
527
528/* Upon syscall entry we just save the callee-saved registers
529 * and not the call-clobbered ones.
530 */
531
532_string_syscall_return:
533 .string "syscall return %ld \n\r\0"
534 .align 4
535
536ENTRY(_sys_call_handler)
537 /* syscalls run with interrupts enabled */
538 ENABLE_INTERRUPTS(r29) // enable interrupts, r29 is temp
539
540 /* r1, EPCR, ESR a already saved */
541 l.sw PT_GPR2(r1),r2
542 /* r3-r8 must be saved because syscall restart relies
543 * on us being able to restart the syscall args... technically
544 * they should be clobbered, otherwise
545 */
546 l.sw PT_GPR3(r1),r3
547 /* r4 already saved */
548 /* r4 holds the EEAR address of the fault, load the original r4 */
549 l.lwz r4,PT_GPR4(r1)
550 l.sw PT_GPR5(r1),r5
551 l.sw PT_GPR6(r1),r6
552 l.sw PT_GPR7(r1),r7
553 l.sw PT_GPR8(r1),r8
554 l.sw PT_GPR9(r1),r9
555 /* r10 already saved */
556 l.sw PT_GPR11(r1),r11
557 l.sw PT_ORIG_GPR11(r1),r11
558 /* r12,r13 already saved */
559
560 /* r14-r28 (even) aren't touched by the syscall fast path below
561 * so we don't need to save them. However, the functions that return
562 * to userspace via a call to switch() DO need to save these because
563 * switch() effectively clobbers them... saving these registers for
564 * such functions is handled in their syscall wrappers (see fork, vfork,
565 * and clone, below).
566
567 /* r30 is the only register we clobber in the fast path */
568 /* r30 already saved */
569/* l.sw PT_GPR30(r1),r30 */
570 /* This is used by do_signal to determine whether to check for
571 * syscall restart or not */
572 l.sw PT_SYSCALLNO(r1),r11
573
574_syscall_check_trace_enter:
575 /* If TIF_SYSCALL_TRACE is set, then we want to do syscall tracing */
576 l.lwz r30,TI_FLAGS(r10)
577 l.andi r30,r30,_TIF_SYSCALL_TRACE
578 l.sfne r30,r0
579 l.bf _syscall_trace_enter
580 l.nop
581
582_syscall_check:
583 /* Ensure that the syscall number is reasonable */
584 l.sfgeui r11,__NR_syscalls
585 l.bf _syscall_badsys
586 l.nop
587
588_syscall_call:
589 l.movhi r29,hi(sys_call_table)
590 l.ori r29,r29,lo(sys_call_table)
591 l.slli r11,r11,2
592 l.add r29,r29,r11
593 l.lwz r29,0(r29)
594
595 l.jalr r29
596 l.nop
597
598_syscall_return:
599 /* All syscalls return here... just pay attention to ret_from_fork
600 * which does it in a round-about way.
601 */
602 l.sw PT_GPR11(r1),r11 // save return value
603
604#if 0
605_syscall_debug:
606 l.movhi r3,hi(_string_syscall_return)
607 l.ori r3,r3,lo(_string_syscall_return)
608 l.ori r27,r0,1
609 l.sw -4(r1),r27
610 l.sw -8(r1),r11
611 l.addi r1,r1,-8
612 l.movhi r27,hi(printk)
613 l.ori r27,r27,lo(printk)
614 l.jalr r27
615 l.nop
616 l.addi r1,r1,8
617#endif
618
619_syscall_check_trace_leave:
620 /* r30 is a callee-saved register so this should still hold the
621 * _TIF_SYSCALL_TRACE flag from _syscall_check_trace_enter above...
622 * _syscall_trace_leave expects syscall result to be in pt_regs->r11.
623 */
624 l.sfne r30,r0
625 l.bf _syscall_trace_leave
626 l.nop
627
628/* This is where the exception-return code begins... interrupts need to be
629 * disabled the rest of the way here because we can't afford to miss any
630 * interrupts that set NEED_RESCHED or SIGNALPENDING... really true? */
631
632_syscall_check_work:
633 /* Here we need to disable interrupts */
634 DISABLE_INTERRUPTS(r27,r29)
635 l.lwz r30,TI_FLAGS(r10)
636 l.andi r30,r30,_TIF_WORK_MASK
637 l.sfne r30,r0
638
639 l.bnf _syscall_resume_userspace
640 l.nop
641
642 /* Work pending follows a different return path, so we need to
643 * make sure that all the call-saved registers get into pt_regs
644 * before branching...
645 */
646 l.sw PT_GPR14(r1),r14
647 l.sw PT_GPR16(r1),r16
648 l.sw PT_GPR18(r1),r18
649 l.sw PT_GPR20(r1),r20
650 l.sw PT_GPR22(r1),r22
651 l.sw PT_GPR24(r1),r24
652 l.sw PT_GPR26(r1),r26
653 l.sw PT_GPR28(r1),r28
654
655 /* _work_pending needs to be called with interrupts disabled */
656 l.j _work_pending
657 l.nop
658
659_syscall_resume_userspace:
660// ENABLE_INTERRUPTS(r29)
661
662
663/* This is the hot path for returning to userspace from a syscall. If there's
664 * work to be done and the branch to _work_pending was taken above, then the
665 * return to userspace will be done via the normal exception return path...
666 * that path restores _all_ registers and will overwrite the "clobbered"
667 * registers with whatever garbage is in pt_regs -- that's OK because those
668 * registers are clobbered anyway and because the extra work is insignificant
669 * in the context of the extra work that _work_pending is doing.
670
671/* Once again, syscalls are special and only guarantee to preserve the
672 * same registers as a normal function call */
673
674/* The assumption here is that the registers r14-r28 (even) are untouched and
675 * don't need to be restored... be sure that that's really the case!
676 */
677
678/* This is still too much... we should only be restoring what we actually
679 * clobbered... we should even be using 'scratch' (odd) regs above so that
680 * we don't need to restore anything, hardly...
681 */
682
683 l.lwz r2,PT_GPR2(r1)
684
685 /* Restore args */
686 /* r3-r8 are technically clobbered, but syscall restart needs these
687 * to be restored...
688 */
689 l.lwz r3,PT_GPR3(r1)
690 l.lwz r4,PT_GPR4(r1)
691 l.lwz r5,PT_GPR5(r1)
692 l.lwz r6,PT_GPR6(r1)
693 l.lwz r7,PT_GPR7(r1)
694 l.lwz r8,PT_GPR8(r1)
695
696 l.lwz r9,PT_GPR9(r1)
697 l.lwz r10,PT_GPR10(r1)
698 l.lwz r11,PT_GPR11(r1)
699
700 /* r30 is the only register we clobber in the fast path */
701 l.lwz r30,PT_GPR30(r1)
702
703 /* Here we use r13-r19 (odd) as scratch regs */
704 l.lwz r13,PT_PC(r1)
705 l.lwz r15,PT_SR(r1)
706 l.lwz r1,PT_SP(r1)
707 /* Interrupts need to be disabled for setting EPCR and ESR
708 * so that another interrupt doesn't come in here and clobber
709 * them before we can use them for our l.rfe */
710 DISABLE_INTERRUPTS(r17,r19)
711 l.mtspr r0,r13,SPR_EPCR_BASE
712 l.mtspr r0,r15,SPR_ESR_BASE
713 l.rfe
714
715/* End of hot path!
716 * Keep the below tracing and error handling out of the hot path...
717*/
718
719_syscall_trace_enter:
720 /* Here we pass pt_regs to do_syscall_trace_enter. Make sure
721 * that function is really getting all the info it needs as
722 * pt_regs isn't a complete set of userspace regs, just the
723 * ones relevant to the syscall...
724 *
725 * Note use of delay slot for setting argument.
726 */
727 l.jal do_syscall_trace_enter
728 l.addi r3,r1,0
729
730 /* Restore arguments (not preserved across do_syscall_trace_enter)
731 * so that we can do the syscall for real and return to the syscall
732 * hot path.
733 */
734 l.lwz r11,PT_SYSCALLNO(r1)
735 l.lwz r3,PT_GPR3(r1)
736 l.lwz r4,PT_GPR4(r1)
737 l.lwz r5,PT_GPR5(r1)
738 l.lwz r6,PT_GPR6(r1)
739 l.lwz r7,PT_GPR7(r1)
740
741 l.j _syscall_check
742 l.lwz r8,PT_GPR8(r1)
743
744_syscall_trace_leave:
745 l.jal do_syscall_trace_leave
746 l.addi r3,r1,0
747
748 l.j _syscall_check_work
749 l.nop
750
751_syscall_badsys:
752 /* Here we effectively pretend to have executed an imaginary
753 * syscall that returns -ENOSYS and then return to the regular
754 * syscall hot path.
755 * Note that "return value" is set in the delay slot...
756 */
757 l.j _syscall_return
758 l.addi r11,r0,-ENOSYS
759
760/******* END SYSCALL HANDLING *******/
761
762/* ---[ 0xd00: Trap exception ]------------------------------------------ */
763
764UNHANDLED_EXCEPTION(_vector_0xd00,0xd00)
765
766/* ---[ 0xe00: Trap exception ]------------------------------------------ */
767
768EXCEPTION_ENTRY(_trap_handler)
769 /* r4: EA of fault (set by EXCEPTION_HANDLE) */
770 l.jal do_trap
771 l.addi r3,r1,0 /* pt_regs */
772
773 l.j _ret_from_exception
774 l.nop
775
776/* ---[ 0xf00: Reserved exception ]-------------------------------------- */
777
778UNHANDLED_EXCEPTION(_vector_0xf00,0xf00)
779
780/* ---[ 0x1000: Reserved exception ]------------------------------------- */
781
782UNHANDLED_EXCEPTION(_vector_0x1000,0x1000)
783
784/* ---[ 0x1100: Reserved exception ]------------------------------------- */
785
786UNHANDLED_EXCEPTION(_vector_0x1100,0x1100)
787
788/* ---[ 0x1200: Reserved exception ]------------------------------------- */
789
790UNHANDLED_EXCEPTION(_vector_0x1200,0x1200)
791
792/* ---[ 0x1300: Reserved exception ]------------------------------------- */
793
794UNHANDLED_EXCEPTION(_vector_0x1300,0x1300)
795
796/* ---[ 0x1400: Reserved exception ]------------------------------------- */
797
798UNHANDLED_EXCEPTION(_vector_0x1400,0x1400)
799
800/* ---[ 0x1500: Reserved exception ]------------------------------------- */
801
802UNHANDLED_EXCEPTION(_vector_0x1500,0x1500)
803
804/* ---[ 0x1600: Reserved exception ]------------------------------------- */
805
806UNHANDLED_EXCEPTION(_vector_0x1600,0x1600)
807
808/* ---[ 0x1700: Reserved exception ]------------------------------------- */
809
810UNHANDLED_EXCEPTION(_vector_0x1700,0x1700)
811
812/* ---[ 0x1800: Reserved exception ]------------------------------------- */
813
814UNHANDLED_EXCEPTION(_vector_0x1800,0x1800)
815
816/* ---[ 0x1900: Reserved exception ]------------------------------------- */
817
818UNHANDLED_EXCEPTION(_vector_0x1900,0x1900)
819
820/* ---[ 0x1a00: Reserved exception ]------------------------------------- */
821
822UNHANDLED_EXCEPTION(_vector_0x1a00,0x1a00)
823
824/* ---[ 0x1b00: Reserved exception ]------------------------------------- */
825
826UNHANDLED_EXCEPTION(_vector_0x1b00,0x1b00)
827
828/* ---[ 0x1c00: Reserved exception ]------------------------------------- */
829
830UNHANDLED_EXCEPTION(_vector_0x1c00,0x1c00)
831
832/* ---[ 0x1d00: Reserved exception ]------------------------------------- */
833
834UNHANDLED_EXCEPTION(_vector_0x1d00,0x1d00)
835
836/* ---[ 0x1e00: Reserved exception ]------------------------------------- */
837
838UNHANDLED_EXCEPTION(_vector_0x1e00,0x1e00)
839
840/* ---[ 0x1f00: Reserved exception ]------------------------------------- */
841
842UNHANDLED_EXCEPTION(_vector_0x1f00,0x1f00)
843
844/* ========================================================[ return ] === */
845
846_work_pending:
847 /*
848 * if (current_thread_info->flags & _TIF_NEED_RESCHED)
849 * schedule();
850 */
851 l.lwz r5,TI_FLAGS(r10)
852 l.andi r3,r5,_TIF_NEED_RESCHED
853 l.sfnei r3,0
854 l.bnf _work_notifysig
855 l.nop
856 l.jal schedule
857 l.nop
858 l.j _resume_userspace
859 l.nop
860
861/* Handle pending signals and notify-resume requests.
862 * do_notify_resume must be passed the latest pushed pt_regs, not
863 * necessarily the "userspace" ones. Also, pt_regs->syscallno
864 * must be set so that the syscall restart functionality works.
865 */
866_work_notifysig:
867 l.jal do_notify_resume
868 l.ori r3,r1,0 /* pt_regs */
869
870_resume_userspace:
871 DISABLE_INTERRUPTS(r3,r4)
872 l.lwz r3,TI_FLAGS(r10)
873 l.andi r3,r3,_TIF_WORK_MASK
874 l.sfnei r3,0
875 l.bf _work_pending
876 l.nop
877
878_restore_all:
879 RESTORE_ALL
880 /* This returns to userspace code */
881
882
883ENTRY(_ret_from_intr)
884ENTRY(_ret_from_exception)
885 l.lwz r4,PT_SR(r1)
886 l.andi r3,r4,SPR_SR_SM
887 l.sfeqi r3,0
888 l.bnf _restore_all
889 l.nop
890 l.j _resume_userspace
891 l.nop
892
893ENTRY(ret_from_fork)
894 l.jal schedule_tail
895 l.nop
896
897 /* _syscall_returns expect r11 to contain return value */
898 l.lwz r11,PT_GPR11(r1)
899
900 /* The syscall fast path return expects call-saved registers
901 * r12-r28 to be untouched, so we restore them here as they
902 * will have been effectively clobbered when arriving here
903 * via the call to switch()
904 */
905 l.lwz r12,PT_GPR12(r1)
906 l.lwz r14,PT_GPR14(r1)
907 l.lwz r16,PT_GPR16(r1)
908 l.lwz r18,PT_GPR18(r1)
909 l.lwz r20,PT_GPR20(r1)
910 l.lwz r22,PT_GPR22(r1)
911 l.lwz r24,PT_GPR24(r1)
912 l.lwz r26,PT_GPR26(r1)
913 l.lwz r28,PT_GPR28(r1)
914
915 l.j _syscall_return
916 l.nop
917
918/* Since syscalls don't save call-clobbered registers, the args to
919 * kernel_thread_helper will need to be passed through callee-saved
920 * registers and copied to the parameter registers when the thread
921 * begins running.
922 *
923 * See arch/openrisc/kernel/process.c:
924 * The args are passed as follows:
925 * arg1 (r3) : passed in r20
926 * arg2 (r4) : passed in r22
927 */
928
929ENTRY(_kernel_thread_helper)
930 l.or r3,r20,r0
931 l.or r4,r22,r0
932 l.movhi r31,hi(kernel_thread_helper)
933 l.ori r31,r31,lo(kernel_thread_helper)
934 l.jr r31
935 l.nop
936
937
938/* ========================================================[ switch ] === */
939
940/*
941 * This routine switches between two different tasks. The process
942 * state of one is saved on its kernel stack. Then the state
943 * of the other is restored from its kernel stack. The memory
944 * management hardware is updated to the second process's state.
945 * Finally, we can return to the second process, via the 'return'.
946 *
947 * Note: there are two ways to get to the "going out" portion
948 * of this code; either by coming in via the entry (_switch)
949 * or via "fork" which must set up an environment equivalent
950 * to the "_switch" path. If you change this (or in particular, the
951 * SAVE_REGS macro), you'll have to change the fork code also.
952 */
953
954
955/* _switch MUST never lay on page boundry, cause it runs from
956 * effective addresses and beeing interrupted by iTLB miss would kill it.
957 * dTLB miss seams to never accour in the bad place since data accesses
958 * are from task structures which are always page aligned.
959 *
960 * The problem happens in RESTORE_ALL_NO_R11 where we first set the EPCR
961 * register, then load the previous register values and only at the end call
962 * the l.rfe instruction. If get TLB miss in beetwen the EPCR register gets
963 * garbled and we end up calling l.rfe with the wrong EPCR. (same probably
964 * holds for ESR)
965 *
966 * To avoid this problems it is sufficient to align _switch to
967 * some nice round number smaller than it's size...
968 */
969
970/* ABI rules apply here... we either enter _switch via schedule() or via
971 * an imaginary call to which we shall return at return_from_fork. Either
972 * way, we are a function call and only need to preserve the callee-saved
973 * registers when we return. As such, we don't need to save the registers
974 * on the stack that we won't be returning as they were...
975 */
976
977 .align 0x400
978ENTRY(_switch)
979 /* We don't store SR as _switch only gets called in a context where
980 * the SR will be the same going in and coming out... */
981
982 /* Set up new pt_regs struct for saving task state */
983 l.addi r1,r1,-(INT_FRAME_SIZE)
984
985 /* No need to store r1/PT_SP as it goes into KSP below */
986 l.sw PT_GPR2(r1),r2
987 l.sw PT_GPR9(r1),r9
988 /* This is wrong, r12 shouldn't be here... but GCC is broken for the time being
989 * and expects r12 to be callee-saved... */
990 l.sw PT_GPR12(r1),r12
991 l.sw PT_GPR14(r1),r14
992 l.sw PT_GPR16(r1),r16
993 l.sw PT_GPR18(r1),r18
994 l.sw PT_GPR20(r1),r20
995 l.sw PT_GPR22(r1),r22
996 l.sw PT_GPR24(r1),r24
997 l.sw PT_GPR26(r1),r26
998 l.sw PT_GPR28(r1),r28
999 l.sw PT_GPR30(r1),r30
1000
1001 l.addi r11,r10,0 /* Save old 'current' to 'last' return value*/
1002
1003 /* We use thread_info->ksp for storing the address of the above
1004 * structure so that we can get back to it later... we don't want
1005 * to lose the value of thread_info->ksp, though, so store it as
1006 * pt_regs->sp so that we can easily restore it when we are made
1007 * live again...
1008 */
1009
1010 /* Save the old value of thread_info->ksp as pt_regs->sp */
1011 l.lwz r29,TI_KSP(r10)
1012 l.sw PT_SP(r1),r29
1013
1014 /* Swap kernel stack pointers */
1015 l.sw TI_KSP(r10),r1 /* Save old stack pointer */
1016 l.or r10,r4,r0 /* Set up new current_thread_info */
1017 l.lwz r1,TI_KSP(r10) /* Load new stack pointer */
1018
1019 /* Restore the old value of thread_info->ksp */
1020 l.lwz r29,PT_SP(r1)
1021 l.sw TI_KSP(r10),r29
1022
1023 /* ...and restore the registers, except r11 because the return value
1024 * has already been set above.
1025 */
1026 l.lwz r2,PT_GPR2(r1)
1027 l.lwz r9,PT_GPR9(r1)
1028 /* No need to restore r10 */
1029 /* ...and do not restore r11 */
1030
1031 /* This is wrong, r12 shouldn't be here... but GCC is broken for the time being
1032 * and expects r12 to be callee-saved... */
1033 l.lwz r12,PT_GPR12(r1)
1034 l.lwz r14,PT_GPR14(r1)
1035 l.lwz r16,PT_GPR16(r1)
1036 l.lwz r18,PT_GPR18(r1)
1037 l.lwz r20,PT_GPR20(r1)
1038 l.lwz r22,PT_GPR22(r1)
1039 l.lwz r24,PT_GPR24(r1)
1040 l.lwz r26,PT_GPR26(r1)
1041 l.lwz r28,PT_GPR28(r1)
1042 l.lwz r30,PT_GPR30(r1)
1043
1044 /* Unwind stack to pre-switch state */
1045 l.addi r1,r1,(INT_FRAME_SIZE)
1046
1047 /* Return via the link-register back to where we 'came from', where that can be
1048 * either schedule() or return_from_fork()... */
1049 l.jr r9
1050 l.nop
1051
1052/* ==================================================================== */
1053
1054/* These all use the delay slot for setting the argument register, so the
1055 * jump is always happening after the l.addi instruction.
1056 *
1057 * These are all just wrappers that don't touch the link-register r9, so the
1058 * return from the "real" syscall function will return back to the syscall
1059 * code that did the l.jal that brought us here.
1060 */
1061
1062/* fork requires that we save all the callee-saved registers because they
1063 * are all effectively clobbered by the call to _switch. Here we store
1064 * all the registers that aren't touched by the syscall fast path and thus
1065 * weren't saved there.
1066 */
1067
1068_fork_save_extra_regs_and_call:
1069 l.sw PT_GPR14(r1),r14
1070 l.sw PT_GPR16(r1),r16
1071 l.sw PT_GPR18(r1),r18
1072 l.sw PT_GPR20(r1),r20
1073 l.sw PT_GPR22(r1),r22
1074 l.sw PT_GPR24(r1),r24
1075 l.sw PT_GPR26(r1),r26
1076 l.jr r29
1077 l.sw PT_GPR28(r1),r28
1078
1079ENTRY(sys_clone)
1080 l.movhi r29,hi(_sys_clone)
1081 l.ori r29,r29,lo(_sys_clone)
1082 l.j _fork_save_extra_regs_and_call
1083 l.addi r7,r1,0
1084
1085ENTRY(sys_fork)
1086 l.movhi r29,hi(_sys_fork)
1087 l.ori r29,r29,lo(_sys_fork)
1088 l.j _fork_save_extra_regs_and_call
1089 l.addi r3,r1,0
1090
1091ENTRY(sys_execve)
1092 l.j _sys_execve
1093 l.addi r6,r1,0
1094
1095ENTRY(sys_sigaltstack)
1096 l.j _sys_sigaltstack
1097 l.addi r5,r1,0
1098
1099ENTRY(sys_rt_sigreturn)
1100 l.j _sys_rt_sigreturn
1101 l.addi r3,r1,0
1102
1103/* This is a catch-all syscall for atomic instructions for the OpenRISC 1000.
1104 * The functions takes a variable number of parameters depending on which
1105 * particular flavour of atomic you want... parameter 1 is a flag identifying
1106 * the atomic in question. Currently, this function implements the
1107 * following variants:
1108 *
1109 * XCHG:
1110 * @flag: 1
1111 * @ptr1:
1112 * @ptr2:
1113 * Atomically exchange the values in pointers 1 and 2.
1114 *
1115 */
1116
1117ENTRY(sys_or1k_atomic)
1118 /* FIXME: This ignores r3 and always does an XCHG */
1119 DISABLE_INTERRUPTS(r17,r19)
1120 l.lwz r30,0(r4)
1121 l.lwz r28,0(r5)
1122 l.sw 0(r4),r28
1123 l.sw 0(r5),r30
1124 ENABLE_INTERRUPTS(r17)
1125 l.jr r9
1126 l.or r11,r0,r0
1127
1128/* ============================================================[ EOF ]=== */
1/* SPDX-License-Identifier: GPL-2.0-or-later */
2/*
3 * OpenRISC entry.S
4 *
5 * Linux architectural port borrowing liberally from similar works of
6 * others. All original copyrights apply as per the original source
7 * declaration.
8 *
9 * Modifications for the OpenRISC architecture:
10 * Copyright (C) 2003 Matjaz Breskvar <phoenix@bsemi.com>
11 * Copyright (C) 2005 Gyorgy Jeney <nog@bsemi.com>
12 * Copyright (C) 2010-2011 Jonas Bonn <jonas@southpole.se>
13 */
14
15#include <linux/linkage.h>
16#include <linux/pgtable.h>
17
18#include <asm/processor.h>
19#include <asm/unistd.h>
20#include <asm/thread_info.h>
21#include <asm/errno.h>
22#include <asm/spr_defs.h>
23#include <asm/page.h>
24#include <asm/mmu.h>
25#include <asm/asm-offsets.h>
26
27#define DISABLE_INTERRUPTS(t1,t2) \
28 l.mfspr t2,r0,SPR_SR ;\
29 l.movhi t1,hi(~(SPR_SR_IEE|SPR_SR_TEE)) ;\
30 l.ori t1,t1,lo(~(SPR_SR_IEE|SPR_SR_TEE)) ;\
31 l.and t2,t2,t1 ;\
32 l.mtspr r0,t2,SPR_SR
33
34#define ENABLE_INTERRUPTS(t1) \
35 l.mfspr t1,r0,SPR_SR ;\
36 l.ori t1,t1,lo(SPR_SR_IEE|SPR_SR_TEE) ;\
37 l.mtspr r0,t1,SPR_SR
38
39/* =========================================================[ macros ]=== */
40
41#ifdef CONFIG_TRACE_IRQFLAGS
42/*
43 * Trace irq on/off creating a stack frame.
44 */
45#define TRACE_IRQS_OP(trace_op) \
46 l.sw -8(r1),r2 /* store frame pointer */ ;\
47 l.sw -4(r1),r9 /* store return address */ ;\
48 l.addi r2,r1,0 /* move sp to fp */ ;\
49 l.jal trace_op ;\
50 l.addi r1,r1,-8 ;\
51 l.ori r1,r2,0 /* restore sp */ ;\
52 l.lwz r9,-4(r1) /* restore return address */ ;\
53 l.lwz r2,-8(r1) /* restore fp */ ;\
54/*
55 * Trace irq on/off and save registers we need that would otherwise be
56 * clobbered.
57 */
58#define TRACE_IRQS_SAVE(t1,trace_op) \
59 l.sw -12(r1),t1 /* save extra reg */ ;\
60 l.sw -8(r1),r2 /* store frame pointer */ ;\
61 l.sw -4(r1),r9 /* store return address */ ;\
62 l.addi r2,r1,0 /* move sp to fp */ ;\
63 l.jal trace_op ;\
64 l.addi r1,r1,-12 ;\
65 l.ori r1,r2,0 /* restore sp */ ;\
66 l.lwz r9,-4(r1) /* restore return address */ ;\
67 l.lwz r2,-8(r1) /* restore fp */ ;\
68 l.lwz t1,-12(r1) /* restore extra reg */
69
70#define TRACE_IRQS_OFF TRACE_IRQS_OP(trace_hardirqs_off)
71#define TRACE_IRQS_ON TRACE_IRQS_OP(trace_hardirqs_on)
72#define TRACE_IRQS_ON_SYSCALL \
73 TRACE_IRQS_SAVE(r10,trace_hardirqs_on) ;\
74 l.lwz r3,PT_GPR3(r1) ;\
75 l.lwz r4,PT_GPR4(r1) ;\
76 l.lwz r5,PT_GPR5(r1) ;\
77 l.lwz r6,PT_GPR6(r1) ;\
78 l.lwz r7,PT_GPR7(r1) ;\
79 l.lwz r8,PT_GPR8(r1) ;\
80 l.lwz r11,PT_GPR11(r1)
81#define TRACE_IRQS_OFF_ENTRY \
82 l.lwz r5,PT_SR(r1) ;\
83 l.andi r3,r5,(SPR_SR_IEE|SPR_SR_TEE) ;\
84 l.sfeq r5,r0 /* skip trace if irqs were already off */;\
85 l.bf 1f ;\
86 l.nop ;\
87 TRACE_IRQS_SAVE(r4,trace_hardirqs_off) ;\
881:
89#else
90#define TRACE_IRQS_OFF
91#define TRACE_IRQS_ON
92#define TRACE_IRQS_OFF_ENTRY
93#define TRACE_IRQS_ON_SYSCALL
94#endif
95
96/*
97 * We need to disable interrupts at beginning of RESTORE_ALL
98 * since interrupt might come in after we've loaded EPC return address
99 * and overwrite EPC with address somewhere in RESTORE_ALL
100 * which is of course wrong!
101 */
102
103#define RESTORE_ALL \
104 DISABLE_INTERRUPTS(r3,r4) ;\
105 l.lwz r3,PT_PC(r1) ;\
106 l.mtspr r0,r3,SPR_EPCR_BASE ;\
107 l.lwz r3,PT_SR(r1) ;\
108 l.mtspr r0,r3,SPR_ESR_BASE ;\
109 l.lwz r3,PT_FPCSR(r1) ;\
110 l.mtspr r0,r3,SPR_FPCSR ;\
111 l.lwz r2,PT_GPR2(r1) ;\
112 l.lwz r3,PT_GPR3(r1) ;\
113 l.lwz r4,PT_GPR4(r1) ;\
114 l.lwz r5,PT_GPR5(r1) ;\
115 l.lwz r6,PT_GPR6(r1) ;\
116 l.lwz r7,PT_GPR7(r1) ;\
117 l.lwz r8,PT_GPR8(r1) ;\
118 l.lwz r9,PT_GPR9(r1) ;\
119 l.lwz r10,PT_GPR10(r1) ;\
120 l.lwz r11,PT_GPR11(r1) ;\
121 l.lwz r12,PT_GPR12(r1) ;\
122 l.lwz r13,PT_GPR13(r1) ;\
123 l.lwz r14,PT_GPR14(r1) ;\
124 l.lwz r15,PT_GPR15(r1) ;\
125 l.lwz r16,PT_GPR16(r1) ;\
126 l.lwz r17,PT_GPR17(r1) ;\
127 l.lwz r18,PT_GPR18(r1) ;\
128 l.lwz r19,PT_GPR19(r1) ;\
129 l.lwz r20,PT_GPR20(r1) ;\
130 l.lwz r21,PT_GPR21(r1) ;\
131 l.lwz r22,PT_GPR22(r1) ;\
132 l.lwz r23,PT_GPR23(r1) ;\
133 l.lwz r24,PT_GPR24(r1) ;\
134 l.lwz r25,PT_GPR25(r1) ;\
135 l.lwz r26,PT_GPR26(r1) ;\
136 l.lwz r27,PT_GPR27(r1) ;\
137 l.lwz r28,PT_GPR28(r1) ;\
138 l.lwz r29,PT_GPR29(r1) ;\
139 l.lwz r30,PT_GPR30(r1) ;\
140 l.lwz r31,PT_GPR31(r1) ;\
141 l.lwz r1,PT_SP(r1) ;\
142 l.rfe
143
144
145#define EXCEPTION_ENTRY(handler) \
146 .global handler ;\
147handler: ;\
148 /* r1, EPCR, ESR a already saved */ ;\
149 l.sw PT_GPR2(r1),r2 ;\
150 l.sw PT_GPR3(r1),r3 ;\
151 /* r4 already save */ ;\
152 l.sw PT_GPR5(r1),r5 ;\
153 l.sw PT_GPR6(r1),r6 ;\
154 l.sw PT_GPR7(r1),r7 ;\
155 l.sw PT_GPR8(r1),r8 ;\
156 l.sw PT_GPR9(r1),r9 ;\
157 /* r10 already saved */ ;\
158 l.sw PT_GPR11(r1),r11 ;\
159 /* r12 already saved */ ;\
160 l.sw PT_GPR13(r1),r13 ;\
161 l.sw PT_GPR14(r1),r14 ;\
162 l.sw PT_GPR15(r1),r15 ;\
163 l.sw PT_GPR16(r1),r16 ;\
164 l.sw PT_GPR17(r1),r17 ;\
165 l.sw PT_GPR18(r1),r18 ;\
166 l.sw PT_GPR19(r1),r19 ;\
167 l.sw PT_GPR20(r1),r20 ;\
168 l.sw PT_GPR21(r1),r21 ;\
169 l.sw PT_GPR22(r1),r22 ;\
170 l.sw PT_GPR23(r1),r23 ;\
171 l.sw PT_GPR24(r1),r24 ;\
172 l.sw PT_GPR25(r1),r25 ;\
173 l.sw PT_GPR26(r1),r26 ;\
174 l.sw PT_GPR27(r1),r27 ;\
175 l.sw PT_GPR28(r1),r28 ;\
176 l.sw PT_GPR29(r1),r29 ;\
177 /* r30 already save */ ;\
178 l.sw PT_GPR31(r1),r31 ;\
179 TRACE_IRQS_OFF_ENTRY ;\
180 l.mfspr r30,r0,SPR_FPCSR ;\
181 l.sw PT_FPCSR(r1),r30 ;\
182 /* Store -1 in orig_gpr11 for non-syscall exceptions */ ;\
183 l.addi r30,r0,-1 ;\
184 l.sw PT_ORIG_GPR11(r1),r30
185
186#define UNHANDLED_EXCEPTION(handler,vector) \
187 .global handler ;\
188handler: ;\
189 /* r1, EPCR, ESR already saved */ ;\
190 l.sw PT_GPR2(r1),r2 ;\
191 l.sw PT_GPR3(r1),r3 ;\
192 l.sw PT_GPR5(r1),r5 ;\
193 l.sw PT_GPR6(r1),r6 ;\
194 l.sw PT_GPR7(r1),r7 ;\
195 l.sw PT_GPR8(r1),r8 ;\
196 l.sw PT_GPR9(r1),r9 ;\
197 /* r10 already saved */ ;\
198 l.sw PT_GPR11(r1),r11 ;\
199 /* r12 already saved */ ;\
200 l.sw PT_GPR13(r1),r13 ;\
201 l.sw PT_GPR14(r1),r14 ;\
202 l.sw PT_GPR15(r1),r15 ;\
203 l.sw PT_GPR16(r1),r16 ;\
204 l.sw PT_GPR17(r1),r17 ;\
205 l.sw PT_GPR18(r1),r18 ;\
206 l.sw PT_GPR19(r1),r19 ;\
207 l.sw PT_GPR20(r1),r20 ;\
208 l.sw PT_GPR21(r1),r21 ;\
209 l.sw PT_GPR22(r1),r22 ;\
210 l.sw PT_GPR23(r1),r23 ;\
211 l.sw PT_GPR24(r1),r24 ;\
212 l.sw PT_GPR25(r1),r25 ;\
213 l.sw PT_GPR26(r1),r26 ;\
214 l.sw PT_GPR27(r1),r27 ;\
215 l.sw PT_GPR28(r1),r28 ;\
216 l.sw PT_GPR29(r1),r29 ;\
217 /* r30 already saved */ ;\
218 l.sw PT_GPR31(r1),r31 ;\
219 /* Store -1 in orig_gpr11 for non-syscall exceptions */ ;\
220 l.addi r30,r0,-1 ;\
221 l.sw PT_ORIG_GPR11(r1),r30 ;\
222 l.mfspr r30,r0,SPR_FPCSR ;\
223 l.sw PT_FPCSR(r1),r30 ;\
224 l.addi r3,r1,0 ;\
225 /* r4 is exception EA */ ;\
226 l.addi r5,r0,vector ;\
227 l.jal unhandled_exception ;\
228 l.nop ;\
229 l.j _ret_from_exception ;\
230 l.nop
231
232/* clobbers 'reg' */
233#define CLEAR_LWA_FLAG(reg) \
234 l.movhi reg,hi(lwa_flag) ;\
235 l.ori reg,reg,lo(lwa_flag) ;\
236 l.sw 0(reg),r0
237/*
238 * NOTE: one should never assume that SPR_EPC, SPR_ESR, SPR_EEAR
239 * contain the same values as when exception we're handling
240 * occured. in fact they never do. if you need them use
241 * values saved on stack (for SPR_EPC, SPR_ESR) or content
242 * of r4 (for SPR_EEAR). for details look at EXCEPTION_HANDLE()
243 * in 'arch/openrisc/kernel/head.S'
244 */
245
246/* =====================================================[ exceptions] === */
247
248/* ---[ 0x100: RESET exception ]----------------------------------------- */
249
250EXCEPTION_ENTRY(_tng_kernel_start)
251 l.jal _start
252 l.andi r0,r0,0
253
254/* ---[ 0x200: BUS exception ]------------------------------------------- */
255
256EXCEPTION_ENTRY(_bus_fault_handler)
257 CLEAR_LWA_FLAG(r3)
258 /* r4: EA of fault (set by EXCEPTION_HANDLE) */
259 l.jal do_bus_fault
260 l.addi r3,r1,0 /* pt_regs */
261
262 l.j _ret_from_exception
263 l.nop
264
265/* ---[ 0x300: Data Page Fault exception ]------------------------------- */
266EXCEPTION_ENTRY(_dtlb_miss_page_fault_handler)
267 CLEAR_LWA_FLAG(r3)
268 l.and r5,r5,r0
269 l.j 1f
270 l.nop
271
272EXCEPTION_ENTRY(_data_page_fault_handler)
273 CLEAR_LWA_FLAG(r3)
274 /* set up parameters for do_page_fault */
275 l.ori r5,r0,0x300 // exception vector
2761:
277 l.addi r3,r1,0 // pt_regs
278 /* r4 set be EXCEPTION_HANDLE */ // effective address of fault
279
280#ifdef CONFIG_OPENRISC_NO_SPR_SR_DSX
281 l.lwz r6,PT_PC(r3) // address of an offending insn
282 l.lwz r6,0(r6) // instruction that caused pf
283
284 l.srli r6,r6,26 // check opcode for jump insn
285 l.sfeqi r6,0 // l.j
286 l.bf 8f
287 l.sfeqi r6,1 // l.jal
288 l.bf 8f
289 l.sfeqi r6,3 // l.bnf
290 l.bf 8f
291 l.sfeqi r6,4 // l.bf
292 l.bf 8f
293 l.sfeqi r6,0x11 // l.jr
294 l.bf 8f
295 l.sfeqi r6,0x12 // l.jalr
296 l.bf 8f
297 l.nop
298
299 l.j 9f
300 l.nop
301
3028: // offending insn is in delay slot
303 l.lwz r6,PT_PC(r3) // address of an offending insn
304 l.addi r6,r6,4
305 l.lwz r6,0(r6) // instruction that caused pf
306 l.srli r6,r6,26 // get opcode
3079: // offending instruction opcode loaded in r6
308
309#else
310
311 l.mfspr r6,r0,SPR_SR // SR
312 l.andi r6,r6,SPR_SR_DSX // check for delay slot exception
313 l.sfne r6,r0 // exception happened in delay slot
314 l.bnf 7f
315 l.lwz r6,PT_PC(r3) // address of an offending insn
316
317 l.addi r6,r6,4 // offending insn is in delay slot
3187:
319 l.lwz r6,0(r6) // instruction that caused pf
320 l.srli r6,r6,26 // check opcode for write access
321#endif
322
323 l.sfgeui r6,0x33 // check opcode for write access
324 l.bnf 1f
325 l.sfleui r6,0x37
326 l.bnf 1f
327 l.ori r6,r0,0x1 // write access
328 l.j 2f
329 l.nop
3301: l.ori r6,r0,0x0 // !write access
3312:
332
333 /* call fault.c handler in openrisc/mm/fault.c */
334 l.jal do_page_fault
335 l.nop
336 l.j _ret_from_exception
337 l.nop
338
339/* ---[ 0x400: Insn Page Fault exception ]------------------------------- */
340EXCEPTION_ENTRY(_itlb_miss_page_fault_handler)
341 CLEAR_LWA_FLAG(r3)
342 l.and r5,r5,r0
343 l.j 1f
344 l.nop
345
346EXCEPTION_ENTRY(_insn_page_fault_handler)
347 CLEAR_LWA_FLAG(r3)
348 /* set up parameters for do_page_fault */
349 l.ori r5,r0,0x400 // exception vector
3501:
351 l.addi r3,r1,0 // pt_regs
352 /* r4 set be EXCEPTION_HANDLE */ // effective address of fault
353 l.ori r6,r0,0x0 // !write access
354
355 /* call fault.c handler in openrisc/mm/fault.c */
356 l.jal do_page_fault
357 l.nop
358 l.j _ret_from_exception
359 l.nop
360
361
362/* ---[ 0x500: Timer exception ]----------------------------------------- */
363
364EXCEPTION_ENTRY(_timer_handler)
365 CLEAR_LWA_FLAG(r3)
366 l.jal timer_interrupt
367 l.addi r3,r1,0 /* pt_regs */
368
369 l.j _ret_from_intr
370 l.nop
371
372/* ---[ 0x600: Alignment exception ]-------------------------------------- */
373
374EXCEPTION_ENTRY(_alignment_handler)
375 CLEAR_LWA_FLAG(r3)
376 /* r4: EA of fault (set by EXCEPTION_HANDLE) */
377 l.jal do_unaligned_access
378 l.addi r3,r1,0 /* pt_regs */
379
380 l.j _ret_from_exception
381 l.nop
382
383#if 0
384EXCEPTION_ENTRY(_alignment_handler)
385// l.mfspr r2,r0,SPR_EEAR_BASE /* Load the effective address */
386 l.addi r2,r4,0
387// l.mfspr r5,r0,SPR_EPCR_BASE /* Load the insn address */
388 l.lwz r5,PT_PC(r1)
389
390 l.lwz r3,0(r5) /* Load insn */
391 l.srli r4,r3,26 /* Shift left to get the insn opcode */
392
393 l.sfeqi r4,0x00 /* Check if the load/store insn is in delay slot */
394 l.bf jmp
395 l.sfeqi r4,0x01
396 l.bf jmp
397 l.sfeqi r4,0x03
398 l.bf jmp
399 l.sfeqi r4,0x04
400 l.bf jmp
401 l.sfeqi r4,0x11
402 l.bf jr
403 l.sfeqi r4,0x12
404 l.bf jr
405 l.nop
406 l.j 1f
407 l.addi r5,r5,4 /* Increment PC to get return insn address */
408
409jmp:
410 l.slli r4,r3,6 /* Get the signed extended jump length */
411 l.srai r4,r4,4
412
413 l.lwz r3,4(r5) /* Load the real load/store insn */
414
415 l.add r5,r5,r4 /* Calculate jump target address */
416
417 l.j 1f
418 l.srli r4,r3,26 /* Shift left to get the insn opcode */
419
420jr:
421 l.slli r4,r3,9 /* Shift to get the reg nb */
422 l.andi r4,r4,0x7c
423
424 l.lwz r3,4(r5) /* Load the real load/store insn */
425
426 l.add r4,r4,r1 /* Load the jump register value from the stack */
427 l.lwz r5,0(r4)
428
429 l.srli r4,r3,26 /* Shift left to get the insn opcode */
430
431
4321:
433// l.mtspr r0,r5,SPR_EPCR_BASE
434 l.sw PT_PC(r1),r5
435
436 l.sfeqi r4,0x26
437 l.bf lhs
438 l.sfeqi r4,0x25
439 l.bf lhz
440 l.sfeqi r4,0x22
441 l.bf lws
442 l.sfeqi r4,0x21
443 l.bf lwz
444 l.sfeqi r4,0x37
445 l.bf sh
446 l.sfeqi r4,0x35
447 l.bf sw
448 l.nop
449
4501: l.j 1b /* I don't know what to do */
451 l.nop
452
453lhs: l.lbs r5,0(r2)
454 l.slli r5,r5,8
455 l.lbz r6,1(r2)
456 l.or r5,r5,r6
457 l.srli r4,r3,19
458 l.andi r4,r4,0x7c
459 l.add r4,r4,r1
460 l.j align_end
461 l.sw 0(r4),r5
462
463lhz: l.lbz r5,0(r2)
464 l.slli r5,r5,8
465 l.lbz r6,1(r2)
466 l.or r5,r5,r6
467 l.srli r4,r3,19
468 l.andi r4,r4,0x7c
469 l.add r4,r4,r1
470 l.j align_end
471 l.sw 0(r4),r5
472
473lws: l.lbs r5,0(r2)
474 l.slli r5,r5,24
475 l.lbz r6,1(r2)
476 l.slli r6,r6,16
477 l.or r5,r5,r6
478 l.lbz r6,2(r2)
479 l.slli r6,r6,8
480 l.or r5,r5,r6
481 l.lbz r6,3(r2)
482 l.or r5,r5,r6
483 l.srli r4,r3,19
484 l.andi r4,r4,0x7c
485 l.add r4,r4,r1
486 l.j align_end
487 l.sw 0(r4),r5
488
489lwz: l.lbz r5,0(r2)
490 l.slli r5,r5,24
491 l.lbz r6,1(r2)
492 l.slli r6,r6,16
493 l.or r5,r5,r6
494 l.lbz r6,2(r2)
495 l.slli r6,r6,8
496 l.or r5,r5,r6
497 l.lbz r6,3(r2)
498 l.or r5,r5,r6
499 l.srli r4,r3,19
500 l.andi r4,r4,0x7c
501 l.add r4,r4,r1
502 l.j align_end
503 l.sw 0(r4),r5
504
505sh:
506 l.srli r4,r3,9
507 l.andi r4,r4,0x7c
508 l.add r4,r4,r1
509 l.lwz r5,0(r4)
510 l.sb 1(r2),r5
511 l.srli r5,r5,8
512 l.j align_end
513 l.sb 0(r2),r5
514
515sw:
516 l.srli r4,r3,9
517 l.andi r4,r4,0x7c
518 l.add r4,r4,r1
519 l.lwz r5,0(r4)
520 l.sb 3(r2),r5
521 l.srli r5,r5,8
522 l.sb 2(r2),r5
523 l.srli r5,r5,8
524 l.sb 1(r2),r5
525 l.srli r5,r5,8
526 l.j align_end
527 l.sb 0(r2),r5
528
529align_end:
530 l.j _ret_from_intr
531 l.nop
532#endif
533
534/* ---[ 0x700: Illegal insn exception ]---------------------------------- */
535
536EXCEPTION_ENTRY(_illegal_instruction_handler)
537 /* r4: EA of fault (set by EXCEPTION_HANDLE) */
538 l.jal do_illegal_instruction
539 l.addi r3,r1,0 /* pt_regs */
540
541 l.j _ret_from_exception
542 l.nop
543
544/* ---[ 0x800: External interrupt exception ]---------------------------- */
545
546EXCEPTION_ENTRY(_external_irq_handler)
547#ifdef CONFIG_OPENRISC_ESR_EXCEPTION_BUG_CHECK
548 l.lwz r4,PT_SR(r1) // were interrupts enabled ?
549 l.andi r4,r4,SPR_SR_IEE
550 l.sfeqi r4,0
551 l.bnf 1f // ext irq enabled, all ok.
552 l.nop
553
554#ifdef CONFIG_PRINTK
555 l.addi r1,r1,-0x8
556 l.movhi r3,hi(42f)
557 l.ori r3,r3,lo(42f)
558 l.sw 0x0(r1),r3
559 l.jal _printk
560 l.sw 0x4(r1),r4
561 l.addi r1,r1,0x8
562
563 .section .rodata, "a"
56442:
565 .string "\n\rESR interrupt bug: in _external_irq_handler (ESR %x)\n\r"
566 .align 4
567 .previous
568#endif
569
570 l.ori r4,r4,SPR_SR_IEE // fix the bug
571// l.sw PT_SR(r1),r4
5721:
573#endif
574 CLEAR_LWA_FLAG(r3)
575 l.addi r3,r1,0
576 l.movhi r8,hi(generic_handle_arch_irq)
577 l.ori r8,r8,lo(generic_handle_arch_irq)
578 l.jalr r8
579 l.nop
580 l.j _ret_from_intr
581 l.nop
582
583/* ---[ 0x900: DTLB miss exception ]------------------------------------- */
584
585
586/* ---[ 0xa00: ITLB miss exception ]------------------------------------- */
587
588
589/* ---[ 0xb00: Range exception ]----------------------------------------- */
590
591UNHANDLED_EXCEPTION(_vector_0xb00,0xb00)
592
593/* ---[ 0xc00: Syscall exception ]--------------------------------------- */
594
595/*
596 * Syscalls are a special type of exception in that they are
597 * _explicitly_ invoked by userspace and can therefore be
598 * held to conform to the same ABI as normal functions with
599 * respect to whether registers are preserved across the call
600 * or not.
601 */
602
603/* Upon syscall entry we just save the callee-saved registers
604 * and not the call-clobbered ones.
605 */
606
607_string_syscall_return:
608 .string "syscall r9:0x%08x -> syscall(%ld) return %ld\0"
609 .align 4
610
611ENTRY(_sys_call_handler)
612 /* r1, EPCR, ESR a already saved */
613 l.sw PT_GPR2(r1),r2
614 /* r3-r8 must be saved because syscall restart relies
615 * on us being able to restart the syscall args... technically
616 * they should be clobbered, otherwise
617 */
618 l.sw PT_GPR3(r1),r3
619 /*
620 * r4 already saved
621 * r4 holds the EEAR address of the fault, use it as screatch reg and
622 * then load the original r4
623 */
624 CLEAR_LWA_FLAG(r4)
625 l.lwz r4,PT_GPR4(r1)
626 l.sw PT_GPR5(r1),r5
627 l.sw PT_GPR6(r1),r6
628 l.sw PT_GPR7(r1),r7
629 l.sw PT_GPR8(r1),r8
630 l.sw PT_GPR9(r1),r9
631 /* r10 already saved */
632 l.sw PT_GPR11(r1),r11
633 /* orig_gpr11 must be set for syscalls */
634 l.sw PT_ORIG_GPR11(r1),r11
635 /* r12,r13 already saved */
636
637 /* r14-r28 (even) aren't touched by the syscall fast path below
638 * so we don't need to save them. However, the functions that return
639 * to userspace via a call to switch() DO need to save these because
640 * switch() effectively clobbers them... saving these registers for
641 * such functions is handled in their syscall wrappers (see fork, vfork,
642 * and clone, below).
643
644 /* r30 is the only register we clobber in the fast path */
645 /* r30 already saved */
646/* l.sw PT_GPR30(r1),r30 */
647
648_syscall_check_trace_enter:
649 /* syscalls run with interrupts enabled */
650 TRACE_IRQS_ON_SYSCALL
651 ENABLE_INTERRUPTS(r29) // enable interrupts, r29 is temp
652
653 /* If TIF_SYSCALL_TRACE is set, then we want to do syscall tracing */
654 l.lwz r30,TI_FLAGS(r10)
655 l.andi r30,r30,_TIF_SYSCALL_TRACE
656 l.sfne r30,r0
657 l.bf _syscall_trace_enter
658 l.nop
659
660_syscall_check:
661 /* Ensure that the syscall number is reasonable */
662 l.sfgeui r11,__NR_syscalls
663 l.bf _syscall_badsys
664 l.nop
665
666_syscall_call:
667 l.movhi r29,hi(sys_call_table)
668 l.ori r29,r29,lo(sys_call_table)
669 l.slli r11,r11,2
670 l.add r29,r29,r11
671 l.lwz r29,0(r29)
672
673 l.jalr r29
674 l.nop
675
676_syscall_return:
677 /* All syscalls return here... just pay attention to ret_from_fork
678 * which does it in a round-about way.
679 */
680 l.sw PT_GPR11(r1),r11 // save return value
681
682#if 0
683_syscall_debug:
684 l.movhi r3,hi(_string_syscall_return)
685 l.ori r3,r3,lo(_string_syscall_return)
686 l.ori r27,r0,2
687 l.sw -4(r1),r27
688 l.sw -8(r1),r11
689 l.lwz r29,PT_ORIG_GPR11(r1)
690 l.sw -12(r1),r29
691 l.lwz r29,PT_GPR9(r1)
692 l.sw -16(r1),r29
693 l.movhi r27,hi(_printk)
694 l.ori r27,r27,lo(_printk)
695 l.jalr r27
696 l.addi r1,r1,-16
697 l.addi r1,r1,16
698#endif
699#if 0
700_syscall_show_regs:
701 l.movhi r27,hi(show_registers)
702 l.ori r27,r27,lo(show_registers)
703 l.jalr r27
704 l.or r3,r1,r1
705#endif
706
707_syscall_check_trace_leave:
708 /* r30 is a callee-saved register so this should still hold the
709 * _TIF_SYSCALL_TRACE flag from _syscall_check_trace_enter above...
710 * _syscall_trace_leave expects syscall result to be in pt_regs->r11.
711 */
712 l.sfne r30,r0
713 l.bf _syscall_trace_leave
714 l.nop
715
716/* This is where the exception-return code begins... interrupts need to be
717 * disabled the rest of the way here because we can't afford to miss any
718 * interrupts that set NEED_RESCHED or SIGNALPENDING... really true? */
719
720_syscall_check_work:
721 /* Here we need to disable interrupts */
722 DISABLE_INTERRUPTS(r27,r29)
723 TRACE_IRQS_OFF
724 l.lwz r30,TI_FLAGS(r10)
725 l.andi r30,r30,_TIF_WORK_MASK
726 l.sfne r30,r0
727
728 l.bnf _syscall_resume_userspace
729 l.nop
730
731 /* Work pending follows a different return path, so we need to
732 * make sure that all the call-saved registers get into pt_regs
733 * before branching...
734 */
735 l.sw PT_GPR14(r1),r14
736 l.sw PT_GPR16(r1),r16
737 l.sw PT_GPR18(r1),r18
738 l.sw PT_GPR20(r1),r20
739 l.sw PT_GPR22(r1),r22
740 l.sw PT_GPR24(r1),r24
741 l.sw PT_GPR26(r1),r26
742 l.sw PT_GPR28(r1),r28
743
744 /* _work_pending needs to be called with interrupts disabled */
745 l.j _work_pending
746 l.nop
747
748_syscall_resume_userspace:
749// ENABLE_INTERRUPTS(r29)
750
751
752/* This is the hot path for returning to userspace from a syscall. If there's
753 * work to be done and the branch to _work_pending was taken above, then the
754 * return to userspace will be done via the normal exception return path...
755 * that path restores _all_ registers and will overwrite the "clobbered"
756 * registers with whatever garbage is in pt_regs -- that's OK because those
757 * registers are clobbered anyway and because the extra work is insignificant
758 * in the context of the extra work that _work_pending is doing.
759
760/* Once again, syscalls are special and only guarantee to preserve the
761 * same registers as a normal function call */
762
763/* The assumption here is that the registers r14-r28 (even) are untouched and
764 * don't need to be restored... be sure that that's really the case!
765 */
766
767/* This is still too much... we should only be restoring what we actually
768 * clobbered... we should even be using 'scratch' (odd) regs above so that
769 * we don't need to restore anything, hardly...
770 */
771
772 l.lwz r2,PT_GPR2(r1)
773
774 /* Restore args */
775 /* r3-r8 are technically clobbered, but syscall restart needs these
776 * to be restored...
777 */
778 l.lwz r3,PT_GPR3(r1)
779 l.lwz r4,PT_GPR4(r1)
780 l.lwz r5,PT_GPR5(r1)
781 l.lwz r6,PT_GPR6(r1)
782 l.lwz r7,PT_GPR7(r1)
783 l.lwz r8,PT_GPR8(r1)
784
785 l.lwz r9,PT_GPR9(r1)
786 l.lwz r10,PT_GPR10(r1)
787 l.lwz r11,PT_GPR11(r1)
788
789 /* r30 is the only register we clobber in the fast path */
790 l.lwz r30,PT_GPR30(r1)
791
792 /* Here we use r13-r19 (odd) as scratch regs */
793 l.lwz r13,PT_PC(r1)
794 l.lwz r15,PT_SR(r1)
795 l.lwz r1,PT_SP(r1)
796 /* Interrupts need to be disabled for setting EPCR and ESR
797 * so that another interrupt doesn't come in here and clobber
798 * them before we can use them for our l.rfe */
799 DISABLE_INTERRUPTS(r17,r19)
800 l.mtspr r0,r13,SPR_EPCR_BASE
801 l.mtspr r0,r15,SPR_ESR_BASE
802 l.rfe
803
804/* End of hot path!
805 * Keep the below tracing and error handling out of the hot path...
806*/
807
808_syscall_trace_enter:
809 /* Here we pass pt_regs to do_syscall_trace_enter. Make sure
810 * that function is really getting all the info it needs as
811 * pt_regs isn't a complete set of userspace regs, just the
812 * ones relevant to the syscall...
813 *
814 * Note use of delay slot for setting argument.
815 */
816 l.jal do_syscall_trace_enter
817 l.addi r3,r1,0
818
819 /* Restore arguments (not preserved across do_syscall_trace_enter)
820 * so that we can do the syscall for real and return to the syscall
821 * hot path.
822 */
823 l.lwz r11,PT_GPR11(r1)
824 l.lwz r3,PT_GPR3(r1)
825 l.lwz r4,PT_GPR4(r1)
826 l.lwz r5,PT_GPR5(r1)
827 l.lwz r6,PT_GPR6(r1)
828 l.lwz r7,PT_GPR7(r1)
829
830 l.j _syscall_check
831 l.lwz r8,PT_GPR8(r1)
832
833_syscall_trace_leave:
834 l.jal do_syscall_trace_leave
835 l.addi r3,r1,0
836
837 l.j _syscall_check_work
838 l.nop
839
840_syscall_badsys:
841 /* Here we effectively pretend to have executed an imaginary
842 * syscall that returns -ENOSYS and then return to the regular
843 * syscall hot path.
844 * Note that "return value" is set in the delay slot...
845 */
846 l.j _syscall_return
847 l.addi r11,r0,-ENOSYS
848
849/******* END SYSCALL HANDLING *******/
850
851/* ---[ 0xd00: Floating Point exception ]-------------------------------- */
852
853EXCEPTION_ENTRY(_fpe_trap_handler)
854 CLEAR_LWA_FLAG(r3)
855 /* r4: EA of fault (set by EXCEPTION_HANDLE) */
856 l.jal do_fpe_trap
857 l.addi r3,r1,0 /* pt_regs */
858
859 l.j _ret_from_exception
860 l.nop
861
862/* ---[ 0xe00: Trap exception ]------------------------------------------ */
863
864EXCEPTION_ENTRY(_trap_handler)
865 CLEAR_LWA_FLAG(r3)
866 /* r4: EA of fault (set by EXCEPTION_HANDLE) */
867 l.jal do_trap
868 l.addi r3,r1,0 /* pt_regs */
869
870 l.j _ret_from_exception
871 l.nop
872
873/* ---[ 0xf00: Reserved exception ]-------------------------------------- */
874
875UNHANDLED_EXCEPTION(_vector_0xf00,0xf00)
876
877/* ---[ 0x1000: Reserved exception ]------------------------------------- */
878
879UNHANDLED_EXCEPTION(_vector_0x1000,0x1000)
880
881/* ---[ 0x1100: Reserved exception ]------------------------------------- */
882
883UNHANDLED_EXCEPTION(_vector_0x1100,0x1100)
884
885/* ---[ 0x1200: Reserved exception ]------------------------------------- */
886
887UNHANDLED_EXCEPTION(_vector_0x1200,0x1200)
888
889/* ---[ 0x1300: Reserved exception ]------------------------------------- */
890
891UNHANDLED_EXCEPTION(_vector_0x1300,0x1300)
892
893/* ---[ 0x1400: Reserved exception ]------------------------------------- */
894
895UNHANDLED_EXCEPTION(_vector_0x1400,0x1400)
896
897/* ---[ 0x1500: Reserved exception ]------------------------------------- */
898
899UNHANDLED_EXCEPTION(_vector_0x1500,0x1500)
900
901/* ---[ 0x1600: Reserved exception ]------------------------------------- */
902
903UNHANDLED_EXCEPTION(_vector_0x1600,0x1600)
904
905/* ---[ 0x1700: Reserved exception ]------------------------------------- */
906
907UNHANDLED_EXCEPTION(_vector_0x1700,0x1700)
908
909/* ---[ 0x1800: Reserved exception ]------------------------------------- */
910
911UNHANDLED_EXCEPTION(_vector_0x1800,0x1800)
912
913/* ---[ 0x1900: Reserved exception ]------------------------------------- */
914
915UNHANDLED_EXCEPTION(_vector_0x1900,0x1900)
916
917/* ---[ 0x1a00: Reserved exception ]------------------------------------- */
918
919UNHANDLED_EXCEPTION(_vector_0x1a00,0x1a00)
920
921/* ---[ 0x1b00: Reserved exception ]------------------------------------- */
922
923UNHANDLED_EXCEPTION(_vector_0x1b00,0x1b00)
924
925/* ---[ 0x1c00: Reserved exception ]------------------------------------- */
926
927UNHANDLED_EXCEPTION(_vector_0x1c00,0x1c00)
928
929/* ---[ 0x1d00: Reserved exception ]------------------------------------- */
930
931UNHANDLED_EXCEPTION(_vector_0x1d00,0x1d00)
932
933/* ---[ 0x1e00: Reserved exception ]------------------------------------- */
934
935UNHANDLED_EXCEPTION(_vector_0x1e00,0x1e00)
936
937/* ---[ 0x1f00: Reserved exception ]------------------------------------- */
938
939UNHANDLED_EXCEPTION(_vector_0x1f00,0x1f00)
940
941/* ========================================================[ return ] === */
942
943_resume_userspace:
944 DISABLE_INTERRUPTS(r3,r4)
945 TRACE_IRQS_OFF
946 l.lwz r4,TI_FLAGS(r10)
947 l.andi r13,r4,_TIF_WORK_MASK
948 l.sfeqi r13,0
949 l.bf _restore_all
950 l.nop
951
952_work_pending:
953 l.lwz r5,PT_ORIG_GPR11(r1)
954 l.sfltsi r5,0
955 l.bnf 1f
956 l.nop
957 l.andi r5,r5,0
9581:
959 l.jal do_work_pending
960 l.ori r3,r1,0 /* pt_regs */
961
962 l.sfeqi r11,0
963 l.bf _restore_all
964 l.nop
965 l.sfltsi r11,0
966 l.bnf 1f
967 l.nop
968 l.and r11,r11,r0
969 l.ori r11,r11,__NR_restart_syscall
970 l.j _syscall_check_trace_enter
971 l.nop
9721:
973 l.lwz r11,PT_ORIG_GPR11(r1)
974 /* Restore arg registers */
975 l.lwz r3,PT_GPR3(r1)
976 l.lwz r4,PT_GPR4(r1)
977 l.lwz r5,PT_GPR5(r1)
978 l.lwz r6,PT_GPR6(r1)
979 l.lwz r7,PT_GPR7(r1)
980 l.j _syscall_check_trace_enter
981 l.lwz r8,PT_GPR8(r1)
982
983_restore_all:
984#ifdef CONFIG_TRACE_IRQFLAGS
985 l.lwz r4,PT_SR(r1)
986 l.andi r3,r4,(SPR_SR_IEE|SPR_SR_TEE)
987 l.sfeq r3,r0 /* skip trace if irqs were off */
988 l.bf skip_hardirqs_on
989 l.nop
990 TRACE_IRQS_ON
991skip_hardirqs_on:
992#endif
993 RESTORE_ALL
994 /* This returns to userspace code */
995
996
997ENTRY(_ret_from_intr)
998ENTRY(_ret_from_exception)
999 l.lwz r4,PT_SR(r1)
1000 l.andi r3,r4,SPR_SR_SM
1001 l.sfeqi r3,0
1002 l.bnf _restore_all
1003 l.nop
1004 l.j _resume_userspace
1005 l.nop
1006
1007ENTRY(ret_from_fork)
1008 l.jal schedule_tail
1009 l.nop
1010
1011 /* Check if we are a kernel thread */
1012 l.sfeqi r20,0
1013 l.bf 1f
1014 l.nop
1015
1016 /* ...we are a kernel thread so invoke the requested callback */
1017 l.jalr r20
1018 l.or r3,r22,r0
1019
10201:
1021 /* _syscall_returns expect r11 to contain return value */
1022 l.lwz r11,PT_GPR11(r1)
1023
1024 /* The syscall fast path return expects call-saved registers
1025 * r14-r28 to be untouched, so we restore them here as they
1026 * will have been effectively clobbered when arriving here
1027 * via the call to switch()
1028 */
1029 l.lwz r14,PT_GPR14(r1)
1030 l.lwz r16,PT_GPR16(r1)
1031 l.lwz r18,PT_GPR18(r1)
1032 l.lwz r20,PT_GPR20(r1)
1033 l.lwz r22,PT_GPR22(r1)
1034 l.lwz r24,PT_GPR24(r1)
1035 l.lwz r26,PT_GPR26(r1)
1036 l.lwz r28,PT_GPR28(r1)
1037
1038 l.j _syscall_return
1039 l.nop
1040
1041/* ========================================================[ switch ] === */
1042
1043/*
1044 * This routine switches between two different tasks. The process
1045 * state of one is saved on its kernel stack. Then the state
1046 * of the other is restored from its kernel stack. The memory
1047 * management hardware is updated to the second process's state.
1048 * Finally, we can return to the second process, via the 'return'.
1049 *
1050 * Note: there are two ways to get to the "going out" portion
1051 * of this code; either by coming in via the entry (_switch)
1052 * or via "fork" which must set up an environment equivalent
1053 * to the "_switch" path. If you change this (or in particular, the
1054 * SAVE_REGS macro), you'll have to change the fork code also.
1055 */
1056
1057
1058/* _switch MUST never lay on page boundry, cause it runs from
1059 * effective addresses and beeing interrupted by iTLB miss would kill it.
1060 * dTLB miss seems to never accour in the bad place since data accesses
1061 * are from task structures which are always page aligned.
1062 *
1063 * The problem happens in RESTORE_ALL where we first set the EPCR
1064 * register, then load the previous register values and only at the end call
1065 * the l.rfe instruction. If get TLB miss in beetwen the EPCR register gets
1066 * garbled and we end up calling l.rfe with the wrong EPCR. (same probably
1067 * holds for ESR)
1068 *
1069 * To avoid this problems it is sufficient to align _switch to
1070 * some nice round number smaller than it's size...
1071 */
1072
1073/* ABI rules apply here... we either enter _switch via schedule() or via
1074 * an imaginary call to which we shall return at return_from_fork. Either
1075 * way, we are a function call and only need to preserve the callee-saved
1076 * registers when we return. As such, we don't need to save the registers
1077 * on the stack that we won't be returning as they were...
1078 */
1079
1080 .align 0x400
1081ENTRY(_switch)
1082 /* We don't store SR as _switch only gets called in a context where
1083 * the SR will be the same going in and coming out... */
1084
1085 /* Set up new pt_regs struct for saving task state */
1086 l.addi r1,r1,-(INT_FRAME_SIZE)
1087
1088 /* No need to store r1/PT_SP as it goes into KSP below */
1089 l.sw PT_GPR2(r1),r2
1090 l.sw PT_GPR9(r1),r9
1091
1092 /* Save callee-saved registers to the new pt_regs */
1093 l.sw PT_GPR14(r1),r14
1094 l.sw PT_GPR16(r1),r16
1095 l.sw PT_GPR18(r1),r18
1096 l.sw PT_GPR20(r1),r20
1097 l.sw PT_GPR22(r1),r22
1098 l.sw PT_GPR24(r1),r24
1099 l.sw PT_GPR26(r1),r26
1100 l.sw PT_GPR28(r1),r28
1101 l.sw PT_GPR30(r1),r30
1102
1103 /* Store the old FPU state to new pt_regs */
1104 l.mfspr r29,r0,SPR_FPCSR
1105 l.sw PT_FPCSR(r1),r29
1106
1107 l.addi r11,r10,0 /* Save old 'current' to 'last' return value*/
1108
1109 /* We use thread_info->ksp for storing the address of the above
1110 * structure so that we can get back to it later... we don't want
1111 * to lose the value of thread_info->ksp, though, so store it as
1112 * pt_regs->sp so that we can easily restore it when we are made
1113 * live again...
1114 */
1115
1116 /* Save the old value of thread_info->ksp as pt_regs->sp */
1117 l.lwz r29,TI_KSP(r10)
1118 l.sw PT_SP(r1),r29
1119
1120 /* Swap kernel stack pointers */
1121 l.sw TI_KSP(r10),r1 /* Save old stack pointer */
1122 l.or r10,r4,r0 /* Set up new current_thread_info */
1123 l.lwz r1,TI_KSP(r10) /* Load new stack pointer */
1124
1125 /* Restore the old value of thread_info->ksp */
1126 l.lwz r29,PT_SP(r1)
1127 l.sw TI_KSP(r10),r29
1128
1129 /* Restore the old value of FPCSR */
1130 l.lwz r29,PT_FPCSR(r1)
1131 l.mtspr r0,r29,SPR_FPCSR
1132
1133 /* ...and restore the registers, except r11 because the return value
1134 * has already been set above.
1135 */
1136 l.lwz r2,PT_GPR2(r1)
1137 l.lwz r9,PT_GPR9(r1)
1138 /* No need to restore r10 */
1139 /* ...and do not restore r11 */
1140
1141 /* Restore callee-saved registers */
1142 l.lwz r14,PT_GPR14(r1)
1143 l.lwz r16,PT_GPR16(r1)
1144 l.lwz r18,PT_GPR18(r1)
1145 l.lwz r20,PT_GPR20(r1)
1146 l.lwz r22,PT_GPR22(r1)
1147 l.lwz r24,PT_GPR24(r1)
1148 l.lwz r26,PT_GPR26(r1)
1149 l.lwz r28,PT_GPR28(r1)
1150 l.lwz r30,PT_GPR30(r1)
1151
1152 /* Unwind stack to pre-switch state */
1153 l.addi r1,r1,(INT_FRAME_SIZE)
1154
1155 /* Return via the link-register back to where we 'came from', where
1156 * that may be either schedule(), ret_from_fork(), or
1157 * ret_from_kernel_thread(). If we are returning to a new thread,
1158 * we are expected to have set up the arg to schedule_tail already,
1159 * hence we do so here unconditionally:
1160 */
1161 l.lwz r3,TI_TASK(r3) /* Load 'prev' as schedule_tail arg */
1162 l.jr r9
1163 l.nop
1164
1165/* ==================================================================== */
1166
1167/* These all use the delay slot for setting the argument register, so the
1168 * jump is always happening after the l.addi instruction.
1169 *
1170 * These are all just wrappers that don't touch the link-register r9, so the
1171 * return from the "real" syscall function will return back to the syscall
1172 * code that did the l.jal that brought us here.
1173 */
1174
1175/* fork requires that we save all the callee-saved registers because they
1176 * are all effectively clobbered by the call to _switch. Here we store
1177 * all the registers that aren't touched by the syscall fast path and thus
1178 * weren't saved there.
1179 */
1180
1181_fork_save_extra_regs_and_call:
1182 l.sw PT_GPR14(r1),r14
1183 l.sw PT_GPR16(r1),r16
1184 l.sw PT_GPR18(r1),r18
1185 l.sw PT_GPR20(r1),r20
1186 l.sw PT_GPR22(r1),r22
1187 l.sw PT_GPR24(r1),r24
1188 l.sw PT_GPR26(r1),r26
1189 l.jr r29
1190 l.sw PT_GPR28(r1),r28
1191
1192ENTRY(__sys_clone)
1193 l.movhi r29,hi(sys_clone)
1194 l.j _fork_save_extra_regs_and_call
1195 l.ori r29,r29,lo(sys_clone)
1196
1197ENTRY(__sys_clone3)
1198 l.movhi r29,hi(sys_clone3)
1199 l.j _fork_save_extra_regs_and_call
1200 l.ori r29,r29,lo(sys_clone3)
1201
1202ENTRY(__sys_fork)
1203 l.movhi r29,hi(sys_fork)
1204 l.j _fork_save_extra_regs_and_call
1205 l.ori r29,r29,lo(sys_fork)
1206
1207ENTRY(sys_rt_sigreturn)
1208 l.jal _sys_rt_sigreturn
1209 l.addi r3,r1,0
1210 l.sfne r30,r0
1211 l.bnf _no_syscall_trace
1212 l.nop
1213 l.jal do_syscall_trace_leave
1214 l.addi r3,r1,0
1215_no_syscall_trace:
1216 l.j _resume_userspace
1217 l.nop
1218
1219/* This is a catch-all syscall for atomic instructions for the OpenRISC 1000.
1220 * The functions takes a variable number of parameters depending on which
1221 * particular flavour of atomic you want... parameter 1 is a flag identifying
1222 * the atomic in question. Currently, this function implements the
1223 * following variants:
1224 *
1225 * XCHG:
1226 * @flag: 1
1227 * @ptr1:
1228 * @ptr2:
1229 * Atomically exchange the values in pointers 1 and 2.
1230 *
1231 */
1232
1233ENTRY(sys_or1k_atomic)
1234 /* FIXME: This ignores r3 and always does an XCHG */
1235 DISABLE_INTERRUPTS(r17,r19)
1236 l.lwz r29,0(r4)
1237 l.lwz r27,0(r5)
1238 l.sw 0(r4),r27
1239 l.sw 0(r5),r29
1240 ENABLE_INTERRUPTS(r17)
1241 l.jr r9
1242 l.or r11,r0,r0
1243
1244/* ============================================================[ EOF ]=== */