| blob | 1175a8539e6cf4b0d0e623c7cccba5db9329d955 |
1 /*
2 * PowerPC version
3 * Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
4 * Rewritten by Cort Dougan (cort@fsmlabs.com) for PReP
5 * Copyright (C) 1996 Cort Dougan <cort@fsmlabs.com>
6 * Adapted for Power Macintosh by Paul Mackerras.
7 * Low-level exception handlers and MMU support
8 * rewritten by Paul Mackerras.
9 * Copyright (C) 1996 Paul Mackerras.
10 * MPC8xx modifications Copyright (C) 1997 Dan Malek (dmalek@jlc.net).
11 *
12 * This file contains the system call entry code, context switch
13 * code, and exception/interrupt return code for PowerPC.
14 *
15 * This program is free software; you can redistribute it and/or
16 * modify it under the terms of the GNU General Public License
17 * as published by the Free Software Foundation; either version
18 * 2 of the License, or (at your option) any later version.
19 *
20 */
22 #include <linux/errno.h>
23 #include <linux/sys.h>
24 #include <linux/threads.h>
25 #include <asm/reg.h>
26 #include <asm/page.h>
27 #include <asm/mmu.h>
28 #include <asm/cputable.h>
29 #include <asm/thread_info.h>
30 #include <asm/ppc_asm.h>
31 #include <asm/asm-offsets.h>
32 #include <asm/unistd.h>
33 #include <asm/ftrace.h>
35 #undef SHOW_SYSCALLS
36 #undef SHOW_SYSCALLS_TASK
38 /*
39 * MSR_KERNEL is > 0x10000 on 4xx/Book-E since it include MSR_CE.
40 */
41 #if MSR_KERNEL >= 0x10000
42 #define LOAD_MSR_KERNEL(r, x) lis r,(x)@h; ori r,r,(x)@l
43 #else
44 #define LOAD_MSR_KERNEL(r, x) li r,(x)
45 #endif
47 #ifdef CONFIG_BOOKE
48 .globl mcheck_transfer_to_handler
49 mcheck_transfer_to_handler:
50 mfspr r0,SPRN_DSRR0
51 stw r0,_DSRR0(r11)
52 mfspr r0,SPRN_DSRR1
53 stw r0,_DSRR1(r11)
54 /* fall through */
56 .globl debug_transfer_to_handler
57 debug_transfer_to_handler:
58 mfspr r0,SPRN_CSRR0
59 stw r0,_CSRR0(r11)
60 mfspr r0,SPRN_CSRR1
61 stw r0,_CSRR1(r11)
62 /* fall through */
64 .globl crit_transfer_to_handler
65 crit_transfer_to_handler:
66 #ifdef CONFIG_PPC_BOOK3E_MMU
67 mfspr r0,SPRN_MAS0
68 stw r0,MAS0(r11)
69 mfspr r0,SPRN_MAS1
70 stw r0,MAS1(r11)
71 mfspr r0,SPRN_MAS2
72 stw r0,MAS2(r11)
73 mfspr r0,SPRN_MAS3
74 stw r0,MAS3(r11)
75 mfspr r0,SPRN_MAS6
76 stw r0,MAS6(r11)
77 #ifdef CONFIG_PHYS_64BIT
78 mfspr r0,SPRN_MAS7
79 stw r0,MAS7(r11)
80 #endif /* CONFIG_PHYS_64BIT */
81 #endif /* CONFIG_PPC_BOOK3E_MMU */
82 #ifdef CONFIG_44x
83 mfspr r0,SPRN_MMUCR
84 stw r0,MMUCR(r11)
85 #endif
86 mfspr r0,SPRN_SRR0
87 stw r0,_SRR0(r11)
88 mfspr r0,SPRN_SRR1
89 stw r0,_SRR1(r11)
91 mfspr r8,SPRN_SPRG_THREAD
92 lwz r0,KSP_LIMIT(r8)
93 stw r0,SAVED_KSP_LIMIT(r11)
94 rlwimi r0,r1,0,0,(31-THREAD_SHIFT)
95 stw r0,KSP_LIMIT(r8)
96 /* fall through */
97 #endif
99 #ifdef CONFIG_40x
100 .globl crit_transfer_to_handler
101 crit_transfer_to_handler:
102 lwz r0,crit_r10@l(0)
103 stw r0,GPR10(r11)
104 lwz r0,crit_r11@l(0)
105 stw r0,GPR11(r11)
106 mfspr r0,SPRN_SRR0
107 stw r0,crit_srr0@l(0)
108 mfspr r0,SPRN_SRR1
109 stw r0,crit_srr1@l(0)
111 mfspr r8,SPRN_SPRG_THREAD
112 lwz r0,KSP_LIMIT(r8)
113 stw r0,saved_ksp_limit@l(0)
114 rlwimi r0,r1,0,0,(31-THREAD_SHIFT)
115 stw r0,KSP_LIMIT(r8)
116 /* fall through */
117 #endif
119 /*
120 * This code finishes saving the registers to the exception frame
121 * and jumps to the appropriate handler for the exception, turning
122 * on address translation.
123 * Note that we rely on the caller having set cr0.eq iff the exception
124 * occurred in kernel mode (i.e. MSR:PR = 0).
125 */
126 .globl transfer_to_handler_full
127 transfer_to_handler_full:
128 SAVE_NVGPRS(r11)
129 /* fall through */
131 .globl transfer_to_handler
132 transfer_to_handler:
133 stw r2,GPR2(r11)
134 stw r12,_NIP(r11)
135 stw r9,_MSR(r11)
136 andi. r2,r9,MSR_PR
137 mfctr r12
138 mfspr r2,SPRN_XER
139 stw r12,_CTR(r11)
140 stw r2,_XER(r11)
141 mfspr r12,SPRN_SPRG_THREAD
142 addi r2,r12,-THREAD
143 tovirt(r2,r2) /* set r2 to current */
144 beq 2f /* if from user, fix up THREAD.regs */
145 addi r11,r1,STACK_FRAME_OVERHEAD
146 stw r11,PT_REGS(r12)
147 #if defined(CONFIG_40x) || defined(CONFIG_BOOKE)
148 /* Check to see if the dbcr0 register is set up to debug. Use the
149 internal debug mode bit to do this. */
150 lwz r12,THREAD_DBCR0(r12)
151 andis. r12,r12,DBCR0_IDM@h
152 beq+ 3f
153 /* From user and task is ptraced - load up global dbcr0 */
154 li r12,-1 /* clear all pending debug events */
155 mtspr SPRN_DBSR,r12
156 lis r11,global_dbcr0@ha
157 tophys(r11,r11)
158 addi r11,r11,global_dbcr0@l
159 #ifdef CONFIG_SMP
160 rlwinm r9,r1,0,0,(31-THREAD_SHIFT)
161 lwz r9,TI_CPU(r9)
162 slwi r9,r9,3
163 add r11,r11,r9
164 #endif
165 lwz r12,0(r11)
166 mtspr SPRN_DBCR0,r12
167 lwz r12,4(r11)
168 addi r12,r12,-1
169 stw r12,4(r11)
170 #endif
171 b 3f
173 2: /* if from kernel, check interrupted DOZE/NAP mode and
174 * check for stack overflow
175 */
176 lwz r9,KSP_LIMIT(r12)
177 cmplw r1,r9 /* if r1 <= ksp_limit */
178 ble- stack_ovf /* then the kernel stack overflowed */
179 5:
180 #if defined(CONFIG_6xx) || defined(CONFIG_E500)
181 rlwinm r9,r1,0,0,31-THREAD_SHIFT
182 tophys(r9,r9) /* check local flags */
183 lwz r12,TI_LOCAL_FLAGS(r9)
184 mtcrf 0x01,r12
185 bt- 31-TLF_NAPPING,4f
186 bt- 31-TLF_SLEEPING,7f
187 #endif /* CONFIG_6xx || CONFIG_E500 */
188 .globl transfer_to_handler_cont
189 transfer_to_handler_cont:
190 3:
191 mflr r9
192 lwz r11,0(r9) /* virtual address of handler */
193 lwz r9,4(r9) /* where to go when done */
194 #ifdef CONFIG_TRACE_IRQFLAGS
195 lis r12,reenable_mmu@h
196 ori r12,r12,reenable_mmu@l
197 mtspr SPRN_SRR0,r12
198 mtspr SPRN_SRR1,r10
199 SYNC
200 RFI
201 reenable_mmu: /* re-enable mmu so we can */
202 mfmsr r10
203 lwz r12,_MSR(r1)
204 xor r10,r10,r12
205 andi. r10,r10,MSR_EE /* Did EE change? */
206 beq 1f
208 /* Save handler and return address into the 2 unused words
209 * of the STACK_FRAME_OVERHEAD (sneak sneak sneak). Everything
210 * else can be recovered from the pt_regs except r3 which for
211 * normal interrupts has been set to pt_regs and for syscalls
212 * is an argument, so we temporarily use ORIG_GPR3 to save it
213 */
214 stw r9,8(r1)
215 stw r11,12(r1)
216 stw r3,ORIG_GPR3(r1)
217 bl trace_hardirqs_off
218 lwz r0,GPR0(r1)
219 lwz r3,ORIG_GPR3(r1)
220 lwz r4,GPR4(r1)
221 lwz r5,GPR5(r1)
222 lwz r6,GPR6(r1)
223 lwz r7,GPR7(r1)
224 lwz r8,GPR8(r1)
225 lwz r9,8(r1)
226 lwz r11,12(r1)
227 1: mtctr r11
228 mtlr r9
229 bctr /* jump to handler */
230 #else /* CONFIG_TRACE_IRQFLAGS */
231 mtspr SPRN_SRR0,r11
232 mtspr SPRN_SRR1,r10
233 mtlr r9
234 SYNC
235 RFI /* jump to handler, enable MMU */
236 #endif /* CONFIG_TRACE_IRQFLAGS */
238 #if defined (CONFIG_6xx) || defined(CONFIG_E500)
239 4: rlwinm r12,r12,0,~_TLF_NAPPING
240 stw r12,TI_LOCAL_FLAGS(r9)
241 b power_save_ppc32_restore
243 7: rlwinm r12,r12,0,~_TLF_SLEEPING
244 stw r12,TI_LOCAL_FLAGS(r9)
245 lwz r9,_MSR(r11) /* if sleeping, clear MSR.EE */
246 rlwinm r9,r9,0,~MSR_EE
247 lwz r12,_LINK(r11) /* and return to address in LR */
248 b fast_exception_return
249 #endif
251 /*
252 * On kernel stack overflow, load up an initial stack pointer
253 * and call StackOverflow(regs), which should not return.
254 */
255 stack_ovf:
256 /* sometimes we use a statically-allocated stack, which is OK. */
257 lis r12,_end@h
258 ori r12,r12,_end@l
259 cmplw r1,r12
260 ble 5b /* r1 <= &_end is OK */
261 SAVE_NVGPRS(r11)
262 addi r3,r1,STACK_FRAME_OVERHEAD
263 lis r1,init_thread_union@ha
264 addi r1,r1,init_thread_union@l
265 addi r1,r1,THREAD_SIZE-STACK_FRAME_OVERHEAD
266 lis r9,StackOverflow@ha
267 addi r9,r9,StackOverflow@l
268 LOAD_MSR_KERNEL(r10,MSR_KERNEL)
269 FIX_SRR1(r10,r12)
270 mtspr SPRN_SRR0,r9
271 mtspr SPRN_SRR1,r10
272 SYNC
273 RFI
275 /*
276 * Handle a system call.
277 */
278 .stabs "arch/powerpc/kernel/",N_SO,0,0,0f
279 .stabs "entry_32.S",N_SO,0,0,0f
280 0:
282 _GLOBAL(DoSyscall)
283 stw r3,ORIG_GPR3(r1)
284 li r12,0
285 stw r12,RESULT(r1)
286 lwz r11,_CCR(r1) /* Clear SO bit in CR */
287 rlwinm r11,r11,0,4,2
288 stw r11,_CCR(r1)
289 #ifdef SHOW_SYSCALLS
290 bl do_show_syscall
291 #endif /* SHOW_SYSCALLS */
292 #ifdef CONFIG_TRACE_IRQFLAGS
293 /* Return from syscalls can (and generally will) hard enable
294 * interrupts. You aren't supposed to call a syscall with
295 * interrupts disabled in the first place. However, to ensure
296 * that we get it right vs. lockdep if it happens, we force
297 * that hard enable here with appropriate tracing if we see
298 * that we have been called with interrupts off
299 */
300 mfmsr r11
301 andi. r12,r11,MSR_EE
302 bne+ 1f
303 /* We came in with interrupts disabled, we enable them now */
304 bl trace_hardirqs_on
305 mfmsr r11
306 lwz r0,GPR0(r1)
307 lwz r3,GPR3(r1)
308 lwz r4,GPR4(r1)
309 ori r11,r11,MSR_EE
310 lwz r5,GPR5(r1)
311 lwz r6,GPR6(r1)
312 lwz r7,GPR7(r1)
313 lwz r8,GPR8(r1)
314 mtmsr r11
315 1:
316 #endif /* CONFIG_TRACE_IRQFLAGS */
317 rlwinm r10,r1,0,0,(31-THREAD_SHIFT) /* current_thread_info() */
318 lwz r11,TI_FLAGS(r10)
319 andi. r11,r11,_TIF_SYSCALL_T_OR_A
320 bne- syscall_dotrace
321 syscall_dotrace_cont:
322 cmplwi 0,r0,NR_syscalls
323 lis r10,sys_call_table@h
324 ori r10,r10,sys_call_table@l
325 slwi r0,r0,2
326 bge- 66f
327 lwzx r10,r10,r0 /* Fetch system call handler [ptr] */
328 mtlr r10
329 addi r9,r1,STACK_FRAME_OVERHEAD
330 PPC440EP_ERR42
331 blrl /* Call handler */
332 .globl ret_from_syscall
333 ret_from_syscall:
334 #ifdef SHOW_SYSCALLS
335 bl do_show_syscall_exit
336 #endif
337 mr r6,r3
338 rlwinm r12,r1,0,0,(31-THREAD_SHIFT) /* current_thread_info() */
339 /* disable interrupts so current_thread_info()->flags can't change */
340 LOAD_MSR_KERNEL(r10,MSR_KERNEL) /* doesn't include MSR_EE */
341 /* Note: We don't bother telling lockdep about it */
342 SYNC
343 MTMSRD(r10)
344 lwz r9,TI_FLAGS(r12)
345 li r8,-_LAST_ERRNO
346 andi. r0,r9,(_TIF_SYSCALL_T_OR_A|_TIF_SINGLESTEP|_TIF_USER_WORK_MASK|_TIF_PERSYSCALL_MASK)
347 bne- syscall_exit_work
348 cmplw 0,r3,r8
349 blt+ syscall_exit_cont
350 lwz r11,_CCR(r1) /* Load CR */
351 neg r3,r3
352 oris r11,r11,0x1000 /* Set SO bit in CR */
353 stw r11,_CCR(r1)
354 syscall_exit_cont:
355 lwz r8,_MSR(r1)
356 #ifdef CONFIG_TRACE_IRQFLAGS
357 /* If we are going to return from the syscall with interrupts
358 * off, we trace that here. It shouldn't happen though but we
359 * want to catch the bugger if it does right ?
360 */
361 andi. r10,r8,MSR_EE
362 bne+ 1f
363 stw r3,GPR3(r1)
364 bl trace_hardirqs_off
365 lwz r3,GPR3(r1)
366 1:
367 #endif /* CONFIG_TRACE_IRQFLAGS */
368 #if defined(CONFIG_4xx) || defined(CONFIG_BOOKE)
369 /* If the process has its own DBCR0 value, load it up. The internal
370 debug mode bit tells us that dbcr0 should be loaded. */
371 lwz r0,THREAD+THREAD_DBCR0(r2)
372 andis. r10,r0,DBCR0_IDM@h
373 bnel- load_dbcr0
374 #endif
375 #ifdef CONFIG_44x
376 lis r4,icache_44x_need_flush@ha
377 lwz r5,icache_44x_need_flush@l(r4)
378 cmplwi cr0,r5,0
379 bne- 2f
380 1:
381 #endif /* CONFIG_44x */
382 BEGIN_FTR_SECTION
383 lwarx r7,0,r1
384 END_FTR_SECTION_IFSET(CPU_FTR_NEED_PAIRED_STWCX)
385 stwcx. r0,0,r1 /* to clear the reservation */
386 lwz r4,_LINK(r1)
387 lwz r5,_CCR(r1)
388 mtlr r4
389 mtcr r5
390 lwz r7,_NIP(r1)
391 FIX_SRR1(r8, r0)
392 lwz r2,GPR2(r1)
393 lwz r1,GPR1(r1)
394 mtspr SPRN_SRR0,r7
395 mtspr SPRN_SRR1,r8
396 SYNC
397 RFI
398 #ifdef CONFIG_44x
399 2: li r7,0
400 iccci r0,r0
401 stw r7,icache_44x_need_flush@l(r4)
402 b 1b
403 #endif /* CONFIG_44x */
405 66: li r3,-ENOSYS
406 b ret_from_syscall
408 .globl ret_from_fork
409 ret_from_fork:
410 REST_NVGPRS(r1)
411 bl schedule_tail
412 li r3,0
413 b ret_from_syscall
415 /* Traced system call support */
416 syscall_dotrace:
417 SAVE_NVGPRS(r1)
418 li r0,0xc00
419 stw r0,_TRAP(r1)
420 addi r3,r1,STACK_FRAME_OVERHEAD
421 bl do_syscall_trace_enter
422 /*
423 * Restore argument registers possibly just changed.
424 * We use the return value of do_syscall_trace_enter
425 * for call number to look up in the table (r0).
426 */
427 mr r0,r3
428 lwz r3,GPR3(r1)
429 lwz r4,GPR4(r1)
430 lwz r5,GPR5(r1)
431 lwz r6,GPR6(r1)
432 lwz r7,GPR7(r1)
433 lwz r8,GPR8(r1)
434 REST_NVGPRS(r1)
435 b syscall_dotrace_cont
437 syscall_exit_work:
438 andi. r0,r9,_TIF_RESTOREALL
439 beq+ 0f
440 REST_NVGPRS(r1)
441 b 2f
442 0: cmplw 0,r3,r8
443 blt+ 1f
444 andi. r0,r9,_TIF_NOERROR
445 bne- 1f
446 lwz r11,_CCR(r1) /* Load CR */
447 neg r3,r3
448 oris r11,r11,0x1000 /* Set SO bit in CR */
449 stw r11,_CCR(r1)
451 1: stw r6,RESULT(r1) /* Save result */
452 stw r3,GPR3(r1) /* Update return value */
453 2: andi. r0,r9,(_TIF_PERSYSCALL_MASK)
454 beq 4f
456 /* Clear per-syscall TIF flags if any are set. */
458 li r11,_TIF_PERSYSCALL_MASK
459 addi r12,r12,TI_FLAGS
460 3: lwarx r8,0,r12
461 andc r8,r8,r11
462 #ifdef CONFIG_IBM405_ERR77
463 dcbt 0,r12
464 #endif
465 stwcx. r8,0,r12
466 bne- 3b
467 subi r12,r12,TI_FLAGS
469 4: /* Anything which requires enabling interrupts? */
470 andi. r0,r9,(_TIF_SYSCALL_T_OR_A|_TIF_SINGLESTEP)
471 beq ret_from_except
473 /* Re-enable interrupts. There is no need to trace that with
474 * lockdep as we are supposed to have IRQs on at this point
475 */
476 ori r10,r10,MSR_EE
477 SYNC
478 MTMSRD(r10)
480 /* Save NVGPRS if they're not saved already */
481 lwz r4,_TRAP(r1)
482 andi. r4,r4,1
483 beq 5f
484 SAVE_NVGPRS(r1)
485 li r4,0xc00
486 stw r4,_TRAP(r1)
487 5:
488 addi r3,r1,STACK_FRAME_OVERHEAD
489 bl do_syscall_trace_leave
490 b ret_from_except_full
492 #ifdef SHOW_SYSCALLS
493 do_show_syscall:
494 #ifdef SHOW_SYSCALLS_TASK
495 lis r11,show_syscalls_task@ha
496 lwz r11,show_syscalls_task@l(r11)
497 cmp 0,r2,r11
498 bnelr
499 #endif
500 stw r31,GPR31(r1)
501 mflr r31
502 lis r3,7f@ha
503 addi r3,r3,7f@l
504 lwz r4,GPR0(r1)
505 lwz r5,GPR3(r1)
506 lwz r6,GPR4(r1)
507 lwz r7,GPR5(r1)
508 lwz r8,GPR6(r1)
509 lwz r9,GPR7(r1)
510 bl printk
511 lis r3,77f@ha
512 addi r3,r3,77f@l
513 lwz r4,GPR8(r1)
514 mr r5,r2
515 bl printk
516 lwz r0,GPR0(r1)
517 lwz r3,GPR3(r1)
518 lwz r4,GPR4(r1)
519 lwz r5,GPR5(r1)
520 lwz r6,GPR6(r1)
521 lwz r7,GPR7(r1)
522 lwz r8,GPR8(r1)
523 mtlr r31
524 lwz r31,GPR31(r1)
525 blr
527 do_show_syscall_exit:
528 #ifdef SHOW_SYSCALLS_TASK
529 lis r11,show_syscalls_task@ha
530 lwz r11,show_syscalls_task@l(r11)
531 cmp 0,r2,r11
532 bnelr
533 #endif
534 stw r31,GPR31(r1)
535 mflr r31
536 stw r3,RESULT(r1) /* Save result */
537 mr r4,r3
538 lis r3,79f@ha
539 addi r3,r3,79f@l
540 bl printk
541 lwz r3,RESULT(r1)
542 mtlr r31
543 lwz r31,GPR31(r1)
544 blr
546 7: .string "syscall %d(%x, %x, %x, %x, %x, "
547 77: .string "%x), current=%p\n"
548 79: .string " -> %x\n"
549 .align 2,0
551 #ifdef SHOW_SYSCALLS_TASK
552 .data
553 .globl show_syscalls_task
554 show_syscalls_task:
555 .long -1
556 .text
557 #endif
558 #endif /* SHOW_SYSCALLS */
560 /*
561 * The fork/clone functions need to copy the full register set into
562 * the child process. Therefore we need to save all the nonvolatile
563 * registers (r13 - r31) before calling the C code.
564 */
565 .globl ppc_fork
566 ppc_fork:
567 SAVE_NVGPRS(r1)
568 lwz r0,_TRAP(r1)
569 rlwinm r0,r0,0,0,30 /* clear LSB to indicate full */
570 stw r0,_TRAP(r1) /* register set saved */
571 b sys_fork
573 .globl ppc_vfork
574 ppc_vfork:
575 SAVE_NVGPRS(r1)
576 lwz r0,_TRAP(r1)
577 rlwinm r0,r0,0,0,30 /* clear LSB to indicate full */
578 stw r0,_TRAP(r1) /* register set saved */
579 b sys_vfork
581 .globl ppc_clone
582 ppc_clone:
583 SAVE_NVGPRS(r1)
584 lwz r0,_TRAP(r1)
585 rlwinm r0,r0,0,0,30 /* clear LSB to indicate full */
586 stw r0,_TRAP(r1) /* register set saved */
587 b sys_clone
589 .globl ppc_swapcontext
590 ppc_swapcontext:
591 SAVE_NVGPRS(r1)
592 lwz r0,_TRAP(r1)
593 rlwinm r0,r0,0,0,30 /* clear LSB to indicate full */
594 stw r0,_TRAP(r1) /* register set saved */
595 b sys_swapcontext
597 /*
598 * Top-level page fault handling.
599 * This is in assembler because if do_page_fault tells us that
600 * it is a bad kernel page fault, we want to save the non-volatile
601 * registers before calling bad_page_fault.
602 */
603 .globl handle_page_fault
604 handle_page_fault:
605 stw r4,_DAR(r1)
606 addi r3,r1,STACK_FRAME_OVERHEAD
607 bl do_page_fault
608 cmpwi r3,0
609 beq+ ret_from_except
610 SAVE_NVGPRS(r1)
611 lwz r0,_TRAP(r1)
612 clrrwi r0,r0,1
613 stw r0,_TRAP(r1)
614 mr r5,r3
615 addi r3,r1,STACK_FRAME_OVERHEAD
616 lwz r4,_DAR(r1)
617 bl bad_page_fault
618 b ret_from_except_full
620 /*
621 * This routine switches between two different tasks. The process
622 * state of one is saved on its kernel stack. Then the state
623 * of the other is restored from its kernel stack. The memory
624 * management hardware is updated to the second process's state.
625 * Finally, we can return to the second process.
626 * On entry, r3 points to the THREAD for the current task, r4
627 * points to the THREAD for the new task.
628 *
629 * This routine is always called with interrupts disabled.
630 *
631 * Note: there are two ways to get to the "going out" portion
632 * of this code; either by coming in via the entry (_switch)
633 * or via "fork" which must set up an environment equivalent
634 * to the "_switch" path. If you change this , you'll have to
635 * change the fork code also.
636 *
637 * The code which creates the new task context is in 'copy_thread'
638 * in arch/ppc/kernel/process.c
639 */
640 _GLOBAL(_switch)
641 stwu r1,-INT_FRAME_SIZE(r1)
642 mflr r0
643 stw r0,INT_FRAME_SIZE+4(r1)
644 /* r3-r12 are caller saved -- Cort */
645 SAVE_NVGPRS(r1)
646 stw r0,_NIP(r1) /* Return to switch caller */
647 mfmsr r11
648 li r0,MSR_FP /* Disable floating-point */
649 #ifdef CONFIG_ALTIVEC
650 BEGIN_FTR_SECTION
651 oris r0,r0,MSR_VEC@h /* Disable altivec */
652 mfspr r12,SPRN_VRSAVE /* save vrsave register value */
653 stw r12,THREAD+THREAD_VRSAVE(r2)
654 END_FTR_SECTION_IFSET(CPU_FTR_ALTIVEC)
655 #endif /* CONFIG_ALTIVEC */
656 #ifdef CONFIG_SPE
657 BEGIN_FTR_SECTION
658 oris r0,r0,MSR_SPE@h /* Disable SPE */
659 mfspr r12,SPRN_SPEFSCR /* save spefscr register value */
660 stw r12,THREAD+THREAD_SPEFSCR(r2)
661 END_FTR_SECTION_IFSET(CPU_FTR_SPE)
662 #endif /* CONFIG_SPE */
663 and. r0,r0,r11 /* FP or altivec or SPE enabled? */
664 beq+ 1f
665 andc r11,r11,r0
666 MTMSRD(r11)
667 isync
668 1: stw r11,_MSR(r1)
669 mfcr r10
670 stw r10,_CCR(r1)
671 stw r1,KSP(r3) /* Set old stack pointer */
673 #ifdef CONFIG_SMP
674 /* We need a sync somewhere here to make sure that if the
675 * previous task gets rescheduled on another CPU, it sees all
676 * stores it has performed on this one.
677 */
678 sync
679 #endif /* CONFIG_SMP */
681 tophys(r0,r4)
682 CLR_TOP32(r0)
683 mtspr SPRN_SPRG_THREAD,r0 /* Update current THREAD phys addr */
684 lwz r1,KSP(r4) /* Load new stack pointer */
686 /* save the old current 'last' for return value */
687 mr r3,r2
688 addi r2,r4,-THREAD /* Update current */
690 #ifdef CONFIG_ALTIVEC
691 BEGIN_FTR_SECTION
692 lwz r0,THREAD+THREAD_VRSAVE(r2)
693 mtspr SPRN_VRSAVE,r0 /* if G4, restore VRSAVE reg */
694 END_FTR_SECTION_IFSET(CPU_FTR_ALTIVEC)
695 #endif /* CONFIG_ALTIVEC */
696 #ifdef CONFIG_SPE
697 BEGIN_FTR_SECTION
698 lwz r0,THREAD+THREAD_SPEFSCR(r2)
699 mtspr SPRN_SPEFSCR,r0 /* restore SPEFSCR reg */
700 END_FTR_SECTION_IFSET(CPU_FTR_SPE)
701 #endif /* CONFIG_SPE */
703 lwz r0,_CCR(r1)
704 mtcrf 0xFF,r0
705 /* r3-r12 are destroyed -- Cort */
706 REST_NVGPRS(r1)
708 lwz r4,_NIP(r1) /* Return to _switch caller in new task */
709 mtlr r4
710 addi r1,r1,INT_FRAME_SIZE
711 blr
713 .globl fast_exception_return
714 fast_exception_return:
715 #if !(defined(CONFIG_4xx) || defined(CONFIG_BOOKE))
716 andi. r10,r9,MSR_RI /* check for recoverable interrupt */
717 beq 1f /* if not, we've got problems */
718 #endif
720 2: REST_4GPRS(3, r11)
721 lwz r10,_CCR(r11)
722 REST_GPR(1, r11)
723 mtcr r10
724 lwz r10,_LINK(r11)
725 mtlr r10
726 REST_GPR(10, r11)
727 mtspr SPRN_SRR1,r9
728 mtspr SPRN_SRR0,r12
729 REST_GPR(9, r11)
730 REST_GPR(12, r11)
731 lwz r11,GPR11(r11)
732 SYNC
733 RFI
735 #if !(defined(CONFIG_4xx) || defined(CONFIG_BOOKE))
736 /* check if the exception happened in a restartable section */
737 1: lis r3,exc_exit_restart_end@ha
738 addi r3,r3,exc_exit_restart_end@l
739 cmplw r12,r3
740 bge 3f
741 lis r4,exc_exit_restart@ha
742 addi r4,r4,exc_exit_restart@l
743 cmplw r12,r4
744 blt 3f
745 lis r3,fee_restarts@ha
746 tophys(r3,r3)
747 lwz r5,fee_restarts@l(r3)
748 addi r5,r5,1
749 stw r5,fee_restarts@l(r3)
750 mr r12,r4 /* restart at exc_exit_restart */
751 b 2b
753 .section .bss
754 .align 2
755 fee_restarts:
756 .space 4
757 .previous
759 /* aargh, a nonrecoverable interrupt, panic */
760 /* aargh, we don't know which trap this is */
761 /* but the 601 doesn't implement the RI bit, so assume it's OK */
762 3:
763 BEGIN_FTR_SECTION
764 b 2b
765 END_FTR_SECTION_IFSET(CPU_FTR_601)
766 li r10,-1
767 stw r10,_TRAP(r11)
768 addi r3,r1,STACK_FRAME_OVERHEAD
769 lis r10,MSR_KERNEL@h
770 ori r10,r10,MSR_KERNEL@l
771 bl transfer_to_handler_full
772 .long nonrecoverable_exception
773 .long ret_from_except
774 #endif
776 .globl ret_from_except_full
777 ret_from_except_full:
778 REST_NVGPRS(r1)
779 /* fall through */
781 .globl ret_from_except
782 ret_from_except:
783 /* Hard-disable interrupts so that current_thread_info()->flags
784 * can't change between when we test it and when we return
785 * from the interrupt. */
786 /* Note: We don't bother telling lockdep about it */
787 LOAD_MSR_KERNEL(r10,MSR_KERNEL)
788 SYNC /* Some chip revs have problems here... */
789 MTMSRD(r10) /* disable interrupts */
791 lwz r3,_MSR(r1) /* Returning to user mode? */
792 andi. r0,r3,MSR_PR
793 beq resume_kernel
795 user_exc_return: /* r10 contains MSR_KERNEL here */
796 /* Check current_thread_info()->flags */
797 rlwinm r9,r1,0,0,(31-THREAD_SHIFT)
798 lwz r9,TI_FLAGS(r9)
799 andi. r0,r9,_TIF_USER_WORK_MASK
800 bne do_work
802 restore_user:
803 #if defined(CONFIG_4xx) || defined(CONFIG_BOOKE)
804 /* Check whether this process has its own DBCR0 value. The internal
805 debug mode bit tells us that dbcr0 should be loaded. */
806 lwz r0,THREAD+THREAD_DBCR0(r2)
807 andis. r10,r0,DBCR0_IDM@h
808 bnel- load_dbcr0
809 #endif
811 #ifdef CONFIG_PREEMPT
812 b restore
814 /* N.B. the only way to get here is from the beq following ret_from_except. */
815 resume_kernel:
816 /* check current_thread_info->preempt_count */
817 rlwinm r9,r1,0,0,(31-THREAD_SHIFT)
818 lwz r0,TI_PREEMPT(r9)
819 cmpwi 0,r0,0 /* if non-zero, just restore regs and return */
820 bne restore
821 lwz r0,TI_FLAGS(r9)
822 andi. r0,r0,_TIF_NEED_RESCHED
823 beq+ restore
824 andi. r0,r3,MSR_EE /* interrupts off? */
825 beq restore /* don't schedule if so */
826 #ifdef CONFIG_TRACE_IRQFLAGS
827 /* Lockdep thinks irqs are enabled, we need to call
828 * preempt_schedule_irq with IRQs off, so we inform lockdep
829 * now that we -did- turn them off already
830 */
831 bl trace_hardirqs_off
832 #endif
833 1: bl preempt_schedule_irq
834 rlwinm r9,r1,0,0,(31-THREAD_SHIFT)
835 lwz r3,TI_FLAGS(r9)
836 andi. r0,r3,_TIF_NEED_RESCHED
837 bne- 1b
838 #ifdef CONFIG_TRACE_IRQFLAGS
839 /* And now, to properly rebalance the above, we tell lockdep they
840 * are being turned back on, which will happen when we return
841 */
842 bl trace_hardirqs_on
843 #endif
844 #else
845 resume_kernel:
846 #endif /* CONFIG_PREEMPT */
848 /* interrupts are hard-disabled at this point */
849 restore:
850 #ifdef CONFIG_44x
851 lis r4,icache_44x_need_flush@ha
852 lwz r5,icache_44x_need_flush@l(r4)
853 cmplwi cr0,r5,0
854 beq+ 1f
855 li r6,0
856 iccci r0,r0
857 stw r6,icache_44x_need_flush@l(r4)
858 1:
859 #endif /* CONFIG_44x */
861 lwz r9,_MSR(r1)
862 #ifdef CONFIG_TRACE_IRQFLAGS
863 /* Lockdep doesn't know about the fact that IRQs are temporarily turned
864 * off in this assembly code while peeking at TI_FLAGS() and such. However
865 * we need to inform it if the exception turned interrupts off, and we
866 * are about to trun them back on.
867 *
868 * The problem here sadly is that we don't know whether the exceptions was
869 * one that turned interrupts off or not. So we always tell lockdep about
870 * turning them on here when we go back to wherever we came from with EE
871 * on, even if that may meen some redudant calls being tracked. Maybe later
872 * we could encode what the exception did somewhere or test the exception
873 * type in the pt_regs but that sounds overkill
874 */
875 andi. r10,r9,MSR_EE
876 beq 1f
877 bl trace_hardirqs_on
878 lwz r9,_MSR(r1)
879 1:
880 #endif /* CONFIG_TRACE_IRQFLAGS */
882 lwz r0,GPR0(r1)
883 lwz r2,GPR2(r1)
884 REST_4GPRS(3, r1)
885 REST_2GPRS(7, r1)
887 lwz r10,_XER(r1)
888 lwz r11,_CTR(r1)
889 mtspr SPRN_XER,r10
890 mtctr r11
892 PPC405_ERR77(0,r1)
893 BEGIN_FTR_SECTION
894 lwarx r11,0,r1
895 END_FTR_SECTION_IFSET(CPU_FTR_NEED_PAIRED_STWCX)
896 stwcx. r0,0,r1 /* to clear the reservation */
898 #if !(defined(CONFIG_4xx) || defined(CONFIG_BOOKE))
899 andi. r10,r9,MSR_RI /* check if this exception occurred */
900 beql nonrecoverable /* at a bad place (MSR:RI = 0) */
902 lwz r10,_CCR(r1)
903 lwz r11,_LINK(r1)
904 mtcrf 0xFF,r10
905 mtlr r11
907 /*
908 * Once we put values in SRR0 and SRR1, we are in a state
909 * where exceptions are not recoverable, since taking an
910 * exception will trash SRR0 and SRR1. Therefore we clear the
911 * MSR:RI bit to indicate this. If we do take an exception,
912 * we can't return to the point of the exception but we
913 * can restart the exception exit path at the label
914 * exc_exit_restart below. -- paulus
915 */
916 LOAD_MSR_KERNEL(r10,MSR_KERNEL & ~MSR_RI)
917 SYNC
918 MTMSRD(r10) /* clear the RI bit */
919 .globl exc_exit_restart
920 exc_exit_restart:
921 lwz r12,_NIP(r1)
922 FIX_SRR1(r9,r10)
923 mtspr SPRN_SRR0,r12
924 mtspr SPRN_SRR1,r9
925 REST_4GPRS(9, r1)
926 lwz r1,GPR1(r1)
927 .globl exc_exit_restart_end
928 exc_exit_restart_end:
929 SYNC
930 RFI
932 #else /* !(CONFIG_4xx || CONFIG_BOOKE) */
933 /*
934 * This is a bit different on 4xx/Book-E because it doesn't have
935 * the RI bit in the MSR.
936 * The TLB miss handler checks if we have interrupted
937 * the exception exit path and restarts it if so
938 * (well maybe one day it will... :).
939 */
940 lwz r11,_LINK(r1)
941 mtlr r11
942 lwz r10,_CCR(r1)
943 mtcrf 0xff,r10
944 REST_2GPRS(9, r1)
945 .globl exc_exit_restart
946 exc_exit_restart:
947 lwz r11,_NIP(r1)
948 lwz r12,_MSR(r1)
949 exc_exit_start:
950 mtspr SPRN_SRR0,r11
951 mtspr SPRN_SRR1,r12
952 REST_2GPRS(11, r1)
953 lwz r1,GPR1(r1)
954 .globl exc_exit_restart_end
955 exc_exit_restart_end:
956 PPC405_ERR77_SYNC
957 rfi
958 b . /* prevent prefetch past rfi */
960 /*
961 * Returning from a critical interrupt in user mode doesn't need
962 * to be any different from a normal exception. For a critical
963 * interrupt in the kernel, we just return (without checking for
964 * preemption) since the interrupt may have happened at some crucial
965 * place (e.g. inside the TLB miss handler), and because we will be
966 * running with r1 pointing into critical_stack, not the current
967 * process's kernel stack (and therefore current_thread_info() will
968 * give the wrong answer).
969 * We have to restore various SPRs that may have been in use at the
970 * time of the critical interrupt.
971 *
972 */
973 #ifdef CONFIG_40x
974 #define PPC_40x_TURN_OFF_MSR_DR \
975 /* avoid any possible TLB misses here by turning off MSR.DR, we \
976 * assume the instructions here are mapped by a pinned TLB entry */ \
977 li r10,MSR_IR; \
978 mtmsr r10; \
979 isync; \
980 tophys(r1, r1);
981 #else
982 #define PPC_40x_TURN_OFF_MSR_DR
983 #endif
985 #define RET_FROM_EXC_LEVEL(exc_lvl_srr0, exc_lvl_srr1, exc_lvl_rfi) \
986 REST_NVGPRS(r1); \
987 lwz r3,_MSR(r1); \
988 andi. r3,r3,MSR_PR; \
989 LOAD_MSR_KERNEL(r10,MSR_KERNEL); \
990 bne user_exc_return; \
991 lwz r0,GPR0(r1); \
992 lwz r2,GPR2(r1); \
993 REST_4GPRS(3, r1); \
994 REST_2GPRS(7, r1); \
995 lwz r10,_XER(r1); \
996 lwz r11,_CTR(r1); \
997 mtspr SPRN_XER,r10; \
998 mtctr r11; \
999 PPC405_ERR77(0,r1); \
1000 stwcx. r0,0,r1; /* to clear the reservation */ \
1001 lwz r11,_LINK(r1); \
1002 mtlr r11; \
1003 lwz r10,_CCR(r1); \
1004 mtcrf 0xff,r10; \
1005 PPC_40x_TURN_OFF_MSR_DR; \
1006 lwz r9,_DEAR(r1); \
1007 lwz r10,_ESR(r1); \
1008 mtspr SPRN_DEAR,r9; \
1009 mtspr SPRN_ESR,r10; \
1010 lwz r11,_NIP(r1); \
1011 lwz r12,_MSR(r1); \
1012 mtspr exc_lvl_srr0,r11; \
1013 mtspr exc_lvl_srr1,r12; \
1014 lwz r9,GPR9(r1); \
1015 lwz r12,GPR12(r1); \
1016 lwz r10,GPR10(r1); \
1017 lwz r11,GPR11(r1); \
1018 lwz r1,GPR1(r1); \
1019 PPC405_ERR77_SYNC; \
1020 exc_lvl_rfi; \
1021 b .; /* prevent prefetch past exc_lvl_rfi */
1023 #define RESTORE_xSRR(exc_lvl_srr0, exc_lvl_srr1) \
1024 lwz r9,_##exc_lvl_srr0(r1); \
1025 lwz r10,_##exc_lvl_srr1(r1); \
1026 mtspr SPRN_##exc_lvl_srr0,r9; \
1027 mtspr SPRN_##exc_lvl_srr1,r10;
1029 #if defined(CONFIG_PPC_BOOK3E_MMU)
1030 #ifdef CONFIG_PHYS_64BIT
1031 #define RESTORE_MAS7 \
1032 lwz r11,MAS7(r1); \
1033 mtspr SPRN_MAS7,r11;
1034 #else
1035 #define RESTORE_MAS7
1036 #endif /* CONFIG_PHYS_64BIT */
1037 #define RESTORE_MMU_REGS \
1038 lwz r9,MAS0(r1); \
1039 lwz r10,MAS1(r1); \
1040 lwz r11,MAS2(r1); \
1041 mtspr SPRN_MAS0,r9; \
1042 lwz r9,MAS3(r1); \
1043 mtspr SPRN_MAS1,r10; \
1044 lwz r10,MAS6(r1); \
1045 mtspr SPRN_MAS2,r11; \
1046 mtspr SPRN_MAS3,r9; \
1047 mtspr SPRN_MAS6,r10; \
1048 RESTORE_MAS7;
1049 #elif defined(CONFIG_44x)
1050 #define RESTORE_MMU_REGS \
1051 lwz r9,MMUCR(r1); \
1052 mtspr SPRN_MMUCR,r9;
1053 #else
1054 #define RESTORE_MMU_REGS
1055 #endif
1057 #ifdef CONFIG_40x
1058 .globl ret_from_crit_exc
1059 ret_from_crit_exc:
1060 mfspr r9,SPRN_SPRG_THREAD
1061 lis r10,saved_ksp_limit@ha;
1062 lwz r10,saved_ksp_limit@l(r10);
1063 tovirt(r9,r9);
1064 stw r10,KSP_LIMIT(r9)
1065 lis r9,crit_srr0@ha;
1066 lwz r9,crit_srr0@l(r9);
1067 lis r10,crit_srr1@ha;
1068 lwz r10,crit_srr1@l(r10);
1069 mtspr SPRN_SRR0,r9;
1070 mtspr SPRN_SRR1,r10;
1071 RET_FROM_EXC_LEVEL(SPRN_CSRR0, SPRN_CSRR1, PPC_RFCI)
1072 #endif /* CONFIG_40x */
1074 #ifdef CONFIG_BOOKE
1075 .globl ret_from_crit_exc
1076 ret_from_crit_exc:
1077 mfspr r9,SPRN_SPRG_THREAD
1078 lwz r10,SAVED_KSP_LIMIT(r1)
1079 stw r10,KSP_LIMIT(r9)
1080 RESTORE_xSRR(SRR0,SRR1);
1081 RESTORE_MMU_REGS;
1082 RET_FROM_EXC_LEVEL(SPRN_CSRR0, SPRN_CSRR1, PPC_RFCI)
1084 .globl ret_from_debug_exc
1085 ret_from_debug_exc:
1086 mfspr r9,SPRN_SPRG_THREAD
1087 lwz r10,SAVED_KSP_LIMIT(r1)
1088 stw r10,KSP_LIMIT(r9)
1089 lwz r9,THREAD_INFO-THREAD(r9)
1090 rlwinm r10,r1,0,0,(31-THREAD_SHIFT)
1091 lwz r10,TI_PREEMPT(r10)
1092 stw r10,TI_PREEMPT(r9)
1093 RESTORE_xSRR(SRR0,SRR1);
1094 RESTORE_xSRR(CSRR0,CSRR1);
1095 RESTORE_MMU_REGS;
1096 RET_FROM_EXC_LEVEL(SPRN_DSRR0, SPRN_DSRR1, PPC_RFDI)
1098 .globl ret_from_mcheck_exc
1099 ret_from_mcheck_exc:
1100 mfspr r9,SPRN_SPRG_THREAD
1101 lwz r10,SAVED_KSP_LIMIT(r1)
1102 stw r10,KSP_LIMIT(r9)
1103 RESTORE_xSRR(SRR0,SRR1);
1104 RESTORE_xSRR(CSRR0,CSRR1);
1105 RESTORE_xSRR(DSRR0,DSRR1);
1106 RESTORE_MMU_REGS;
1107 RET_FROM_EXC_LEVEL(SPRN_MCSRR0, SPRN_MCSRR1, PPC_RFMCI)
1108 #endif /* CONFIG_BOOKE */
1110 /*
1111 * Load the DBCR0 value for a task that is being ptraced,
1112 * having first saved away the global DBCR0. Note that r0
1113 * has the dbcr0 value to set upon entry to this.
1114 */
1115 load_dbcr0:
1116 mfmsr r10 /* first disable debug exceptions */
1117 rlwinm r10,r10,0,~MSR_DE
1118 mtmsr r10
1119 isync
1120 mfspr r10,SPRN_DBCR0
1121 lis r11,global_dbcr0@ha
1122 addi r11,r11,global_dbcr0@l
1123 #ifdef CONFIG_SMP
1124 rlwinm r9,r1,0,0,(31-THREAD_SHIFT)
1125 lwz r9,TI_CPU(r9)
1126 slwi r9,r9,3
1127 add r11,r11,r9
1128 #endif
1129 stw r10,0(r11)
1130 mtspr SPRN_DBCR0,r0
1131 lwz r10,4(r11)
1132 addi r10,r10,1
1133 stw r10,4(r11)
1134 li r11,-1
1135 mtspr SPRN_DBSR,r11 /* clear all pending debug events */
1136 blr
1138 .section .bss
1139 .align 4
1140 global_dbcr0:
1141 .space 8*NR_CPUS
1142 .previous
1143 #endif /* !(CONFIG_4xx || CONFIG_BOOKE) */
1145 do_work: /* r10 contains MSR_KERNEL here */
1146 andi. r0,r9,_TIF_NEED_RESCHED
1147 beq do_user_signal
1149 do_resched: /* r10 contains MSR_KERNEL here */
1150 /* Note: We don't need to inform lockdep that we are enabling
1151 * interrupts here. As far as it knows, they are already enabled
1152 */
1153 ori r10,r10,MSR_EE
1154 SYNC
1155 MTMSRD(r10) /* hard-enable interrupts */
1156 bl schedule
1157 recheck:
1158 /* Note: And we don't tell it we are disabling them again
1159 * neither. Those disable/enable cycles used to peek at
1160 * TI_FLAGS aren't advertised.
1161 */
1162 LOAD_MSR_KERNEL(r10,MSR_KERNEL)
1163 SYNC
1164 MTMSRD(r10) /* disable interrupts */
1165 rlwinm r9,r1,0,0,(31-THREAD_SHIFT)
1166 lwz r9,TI_FLAGS(r9)
1167 andi. r0,r9,_TIF_NEED_RESCHED
1168 bne- do_resched
1169 andi. r0,r9,_TIF_USER_WORK_MASK
1170 beq restore_user
1171 do_user_signal: /* r10 contains MSR_KERNEL here */
1172 ori r10,r10,MSR_EE
1173 SYNC
1174 MTMSRD(r10) /* hard-enable interrupts */
1175 /* save r13-r31 in the exception frame, if not already done */
1176 lwz r3,_TRAP(r1)
1177 andi. r0,r3,1
1178 beq 2f
1179 SAVE_NVGPRS(r1)
1180 rlwinm r3,r3,0,0,30
1181 stw r3,_TRAP(r1)
1182 2: addi r3,r1,STACK_FRAME_OVERHEAD
1183 mr r4,r9
1184 bl do_signal
1185 REST_NVGPRS(r1)
1186 b recheck
1188 /*
1189 * We come here when we are at the end of handling an exception
1190 * that occurred at a place where taking an exception will lose
1191 * state information, such as the contents of SRR0 and SRR1.
1192 */
1193 nonrecoverable:
1194 lis r10,exc_exit_restart_end@ha
1195 addi r10,r10,exc_exit_restart_end@l
1196 cmplw r12,r10
1197 bge 3f
1198 lis r11,exc_exit_restart@ha
1199 addi r11,r11,exc_exit_restart@l
1200 cmplw r12,r11
1201 blt 3f
1202 lis r10,ee_restarts@ha
1203 lwz r12,ee_restarts@l(r10)
1204 addi r12,r12,1
1205 stw r12,ee_restarts@l(r10)
1206 mr r12,r11 /* restart at exc_exit_restart */
1207 blr
1208 3: /* OK, we can't recover, kill this process */
1209 /* but the 601 doesn't implement the RI bit, so assume it's OK */
1210 BEGIN_FTR_SECTION
1211 blr
1212 END_FTR_SECTION_IFSET(CPU_FTR_601)
1213 lwz r3,_TRAP(r1)
1214 andi. r0,r3,1
1215 beq 4f
1216 SAVE_NVGPRS(r1)
1217 rlwinm r3,r3,0,0,30
1218 stw r3,_TRAP(r1)
1219 4: addi r3,r1,STACK_FRAME_OVERHEAD
1220 bl nonrecoverable_exception
1221 /* shouldn't return */
1222 b 4b
1224 .section .bss
1225 .align 2
1226 ee_restarts:
1227 .space 4
1228 .previous
1230 /*
1231 * PROM code for specific machines follows. Put it
1232 * here so it's easy to add arch-specific sections later.
1233 * -- Cort
1234 */
1235 #ifdef CONFIG_PPC_RTAS
1236 /*
1237 * On CHRP, the Run-Time Abstraction Services (RTAS) have to be
1238 * called with the MMU off.
1239 */
1240 _GLOBAL(enter_rtas)
1241 stwu r1,-INT_FRAME_SIZE(r1)
1242 mflr r0
1243 stw r0,INT_FRAME_SIZE+4(r1)
1244 LOAD_REG_ADDR(r4, rtas)
1245 lis r6,1f@ha /* physical return address for rtas */
1246 addi r6,r6,1f@l
1247 tophys(r6,r6)
1248 tophys(r7,r1)
1249 lwz r8,RTASENTRY(r4)
1250 lwz r4,RTASBASE(r4)
1251 mfmsr r9
1252 stw r9,8(r1)
1253 LOAD_MSR_KERNEL(r0,MSR_KERNEL)
1254 SYNC /* disable interrupts so SRR0/1 */
1255 MTMSRD(r0) /* don't get trashed */
1256 li r9,MSR_KERNEL & ~(MSR_IR|MSR_DR)
1257 mtlr r6
1258 mtspr SPRN_SPRG_RTAS,r7
1259 mtspr SPRN_SRR0,r8
1260 mtspr SPRN_SRR1,r9
1261 RFI
1262 1: tophys(r9,r1)
1263 lwz r8,INT_FRAME_SIZE+4(r9) /* get return address */
1264 lwz r9,8(r9) /* original msr value */
1265 FIX_SRR1(r9,r0)
1266 addi r1,r1,INT_FRAME_SIZE
1267 li r0,0
1268 mtspr SPRN_SPRG_RTAS,r0
1269 mtspr SPRN_SRR0,r8
1270 mtspr SPRN_SRR1,r9
1271 RFI /* return to caller */
1273 .globl machine_check_in_rtas
1274 machine_check_in_rtas:
1275 twi 31,0,0
1276 /* XXX load up BATs and panic */
1278 #endif /* CONFIG_PPC_RTAS */
1280 #ifdef CONFIG_FUNCTION_TRACER
1281 #ifdef CONFIG_DYNAMIC_FTRACE
1282 _GLOBAL(mcount)
1283 _GLOBAL(_mcount)
1284 /*
1285 * It is required that _mcount on PPC32 must preserve the
1286 * link register. But we have r0 to play with. We use r0
1287 * to push the return address back to the caller of mcount
1288 * into the ctr register, restore the link register and
1289 * then jump back using the ctr register.
1290 */
1291 mflr r0
1292 mtctr r0
1293 lwz r0, 4(r1)
1294 mtlr r0
1295 bctr
1297 _GLOBAL(ftrace_caller)
1298 MCOUNT_SAVE_FRAME
1299 /* r3 ends up with link register */
1300 subi r3, r3, MCOUNT_INSN_SIZE
1301 .globl ftrace_call
1302 ftrace_call:
1303 bl ftrace_stub
1304 nop
1305 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
1306 .globl ftrace_graph_call
1307 ftrace_graph_call:
1308 b ftrace_graph_stub
1309 _GLOBAL(ftrace_graph_stub)
1310 #endif
1311 MCOUNT_RESTORE_FRAME
1312 /* old link register ends up in ctr reg */
1313 bctr
1314 #else
1315 _GLOBAL(mcount)
1316 _GLOBAL(_mcount)
1318 MCOUNT_SAVE_FRAME
1320 subi r3, r3, MCOUNT_INSN_SIZE
1321 LOAD_REG_ADDR(r5, ftrace_trace_function)
1322 lwz r5,0(r5)
1324 mtctr r5
1325 bctrl
1326 nop
1328 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
1329 b ftrace_graph_caller
1330 #endif
1331 MCOUNT_RESTORE_FRAME
1332 bctr
1333 #endif
1335 _GLOBAL(ftrace_stub)
1336 blr
1338 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
1339 _GLOBAL(ftrace_graph_caller)
1340 /* load r4 with local address */
1341 lwz r4, 44(r1)
1342 subi r4, r4, MCOUNT_INSN_SIZE
1344 /* get the parent address */
1345 addi r3, r1, 52
1347 bl prepare_ftrace_return
1348 nop
1350 MCOUNT_RESTORE_FRAME
1351 /* old link register ends up in ctr reg */
1352 bctr
1354 _GLOBAL(return_to_handler)
1355 /* need to save return values */
1356 stwu r1, -32(r1)
1357 stw r3, 20(r1)
1358 stw r4, 16(r1)
1359 stw r31, 12(r1)
1360 mr r31, r1
1362 bl ftrace_return_to_handler
1363 nop
1365 /* return value has real return address */
1366 mtlr r3
1368 lwz r3, 20(r1)
1369 lwz r4, 16(r1)
1370 lwz r31,12(r1)
1371 lwz r1, 0(r1)
1373 /* Jump back to real return address */
1374 blr
1375 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
1377 #endif /* CONFIG_MCOUNT */