2 * arch/ppc/kernel/head_44x.S
4 * Kernel execution entry point code.
6 * Copyright (c) 1995-1996 Gary Thomas <gdt@linuxppc.org>
7 * Initial PowerPC version.
8 * Copyright (c) 1996 Cort Dougan <cort@cs.nmt.edu>
10 * Copyright (c) 1996 Paul Mackerras <paulus@cs.anu.edu.au>
11 * Low-level exception handers, MMU support, and rewrite.
12 * Copyright (c) 1997 Dan Malek <dmalek@jlc.net>
13 * PowerPC 8xx modifications.
14 * Copyright (c) 1998-1999 TiVo, Inc.
15 * PowerPC 403GCX modifications.
16 * Copyright (c) 1999 Grant Erickson <grant@lcse.umn.edu>
17 * PowerPC 403GCX/405GP modifications.
18 * Copyright 2000 MontaVista Software Inc.
19 * PPC405 modifications
20 * PowerPC 403GCX/405GP modifications.
21 * Author: MontaVista Software, Inc.
22 * frank_rowand@mvista.com or source@mvista.com
23 * debbie_chu@mvista.com
24 * Copyright 2002-2004 MontaVista Software, Inc.
25 * PowerPC 44x support, Matt Porter <mporter@kernel.crashing.org>
27 * This program is free software; you can redistribute it and/or modify it
28 * under the terms of the GNU General Public License as published by the
29 * Free Software Foundation; either version 2 of the License, or (at your
30 * option) any later version.
33 #include <linux/config.h>
34 #include <asm/processor.h>
37 #include <asm/pgtable.h>
38 #include <asm/ibm4xx.h>
39 #include <asm/ibm44x.h>
40 #include <asm/cputable.h>
41 #include <asm/thread_info.h>
42 #include <asm/ppc_asm.h>
43 #include <asm/offsets.h>
49 #define SET_IVOR(vector_number, vector_label) \
50 li r26,vector_label@l; \
51 mtspr SPRN_IVOR##vector_number,r26; \
54 /* As with the other PowerPC ports, it is expected that when code
55 * execution begins here, the following registers contain valid, yet
56 * optional, information:
58 * r3 - Board info structure pointer (DRAM, frequency, MAC address, etc.)
59 * r4 - Starting address of the init RAM disk
60 * r5 - Ending address of the init RAM disk
61 * r6 - Start of kernel command line string (e.g. "mem=128")
62 * r7 - End of kernel command line string
69 * Reserve a word at a fixed location to store the address
74 * Save parameters we are passed
81 li r24,0 /* CPU number */
84 * Set up the initial MMU state
86 * We are still executing code at the virtual address
87 * mappings set by the firmware for the base of RAM.
89 * We first invalidate all TLB entries but the one
90 * we are running from. We then load the KERNELBASE
91 * mappings so we can begin to use kernel addresses
92 * natively and so the interrupt vector locations are
93 * permanently pinned (necessary since Book E
94 * implementations always have translation enabled).
96 * TODO: Use the known TLB entry we are running from to
97 * determine which physical region we are located
98 * in. This can be used to determine where in RAM
99 * (on a shared CPU system) or PCI memory space
100 * (on a DRAMless system) we are located.
101 * For now, we assume a perfect world which means
102 * we are located at the base of DRAM (physical 0).
106 * Search TLB for entry that we are currently using.
107 * Invalidate all entries but the one we are using.
109 /* Load our current PID->MMUCR TID and MSR IS->MMUCR STS */
110 mfspr r3,SPRN_PID /* Get PID */
111 mfmsr r4 /* Get MSR */
112 andi. r4,r4,MSR_IS@l /* TS=1? */
113 beq wmmucr /* If not, leave STS=0 */
114 oris r3,r3,PPC44x_MMUCR_STS@h /* Set STS=1 */
115 wmmucr: mtspr SPRN_MMUCR,r3 /* Put MMUCR */
118 bl invstr /* Find our address */
119 invstr: mflr r5 /* Make it accessible */
120 tlbsx r23,0,r5 /* Find entry we are in */
121 li r4,0 /* Start at TLB entry 0 */
122 li r3,0 /* Set PAGEID inval value */
123 1: cmpw r23,r4 /* Is this our entry? */
124 beq skpinv /* If so, skip the inval */
125 tlbwe r3,r4,PPC44x_TLB_PAGEID /* If not, inval the entry */
126 skpinv: addi r4,r4,1 /* Increment */
127 cmpwi r4,64 /* Are we done? */
128 bne 1b /* If not, repeat */
129 isync /* If so, context change */
132 * Configure and load pinned entry into TLB slot 63.
135 lis r3,KERNELBASE@h /* Load the kernel virtual address */
136 ori r3,r3,KERNELBASE@l
138 /* Kernel is at the base of RAM */
139 li r4, 0 /* Load the kernel physical address */
141 /* Load the kernel PID = 0 */
146 /* Initialize MMUCR */
152 clrrwi r3,r3,10 /* Mask off the effective page number */
153 ori r3,r3,PPC44x_TLB_VALID | PPC44x_TLB_256M
156 clrrwi r4,r4,10 /* Mask off the real page number */
157 /* ERPN is 0 for first 4GB page */
160 /* Added guarded bit to protect against speculative loads/stores */
162 ori r5,r5,(PPC44x_TLB_SW | PPC44x_TLB_SR | PPC44x_TLB_SX | PPC44x_TLB_G)
164 li r0,63 /* TLB slot 63 */
166 tlbwe r3,r0,PPC44x_TLB_PAGEID /* Load the pageid fields */
167 tlbwe r4,r0,PPC44x_TLB_XLAT /* Load the translation fields */
168 tlbwe r5,r0,PPC44x_TLB_ATTRIB /* Load the attrib/access fields */
170 /* Force context change */
179 /* If necessary, invalidate original entry we used */
183 tlbwe r6,r23,PPC44x_TLB_PAGEID
187 #ifdef CONFIG_SERIAL_TEXT_DEBUG
189 * Add temporary UART mapping for early debug. This
190 * mapping must be identical to that used by the early
191 * bootloader code since the same asm/serial.h parameters
192 * are used for polled operation.
196 ori r3,r3,PPC44x_TLB_VALID | PPC44x_TLB_256M
199 lis r4,0x4000 /* RPN is 0x40000000 */
200 ori r4,r4,0x0001 /* ERPN is 1 for second 4GB page */
204 ori r5,r5,(PPC44x_TLB_SW | PPC44x_TLB_SR | PPC44x_TLB_I | PPC44x_TLB_G)
206 li r0,1 /* TLB slot 1 */
208 tlbwe r3,r0,PPC44x_TLB_PAGEID /* Load the pageid fields */
209 tlbwe r4,r0,PPC44x_TLB_XLAT /* Load the translation fields */
210 tlbwe r5,r0,PPC44x_TLB_ATTRIB /* Load the attrib/access fields */
212 ori r3,r3,PPC44x_TLB_TS /* Translation state 1 */
214 li r0,1 /* TLB slot 1 */
216 tlbwe r3,r0,PPC44x_TLB_PAGEID /* Load the pageid fields */
217 tlbwe r4,r0,PPC44x_TLB_XLAT /* Load the translation fields */
218 tlbwe r5,r0,PPC44x_TLB_ATTRIB /* Load the attrib/access fields */
220 /* Force context change */
222 #endif /* CONFIG_SERIAL_TEXT_DEBUG */
224 /* Establish the interrupt vector offsets */
225 SET_IVOR(0, CriticalInput);
226 SET_IVOR(1, MachineCheck);
227 SET_IVOR(2, DataStorage);
228 SET_IVOR(3, InstructionStorage);
229 SET_IVOR(4, ExternalInput);
230 SET_IVOR(5, Alignment);
231 SET_IVOR(6, Program);
232 SET_IVOR(7, FloatingPointUnavailable);
233 SET_IVOR(8, SystemCall);
234 SET_IVOR(9, AuxillaryProcessorUnavailable);
235 SET_IVOR(10, Decrementer);
236 SET_IVOR(11, FixedIntervalTimer);
237 SET_IVOR(12, WatchdogTimer);
238 SET_IVOR(13, DataTLBError);
239 SET_IVOR(14, InstructionTLBError);
242 /* Establish the interrupt vector base */
243 lis r4,interrupt_base@h /* IVPR only uses the high 16-bits */
247 * This is where the main kernel code starts.
252 ori r2,r2,init_task@l
254 /* ptr to current thread */
255 addi r4,r2,THREAD /* init task's THREAD */
259 lis r1,init_thread_union@h
260 ori r1,r1,init_thread_union@l
262 stwu r0,THREAD_SIZE-STACK_FRAME_OVERHEAD(r1)
267 * Decide what sort of machine this is and initialize the MMU.
277 /* Setup PTE pointers for the Abatron bdiGDB */
278 lis r6, swapper_pg_dir@h
279 ori r6, r6, swapper_pg_dir@l
280 lis r5, abatron_pteptrs@h
281 ori r5, r5, abatron_pteptrs@l
283 ori r4, r4, KERNELBASE@l
284 stw r5, 0(r4) /* Save abatron_pteptrs at a fixed location */
288 lis r4,start_kernel@h
289 ori r4,r4,start_kernel@l
291 ori r3,r3,MSR_KERNEL@l
294 rfi /* change context and jump to start_kernel */
297 * Interrupt vector entry code
299 * The Book E MMUs are always on so we don't need to handle
300 * interrupts in real mode as with previous PPC processors. In
301 * this case we handle interrupts in the kernel virtual address
304 * Interrupt vectors are dynamically placed relative to the
305 * interrupt prefix as determined by the address of interrupt_base.
306 * The interrupt vectors offsets are programmed using the labels
307 * for each interrupt vector entry.
309 * Interrupt vectors must be aligned on a 16 byte boundary.
310 * We align on a 32 byte cache line boundary for good measure.
313 #define NORMAL_EXCEPTION_PROLOG \
314 mtspr SPRN_SPRG0,r10; /* save two registers to work with */\
315 mtspr SPRN_SPRG1,r11; \
316 mtspr SPRN_SPRG4W,r1; \
317 mfcr r10; /* save CR in r10 for now */\
318 mfspr r11,SPRN_SRR1; /* check whether user or kernel */\
319 andi. r11,r11,MSR_PR; \
321 mfspr r1,SPRG3; /* if from user, start at top of */\
322 lwz r1,THREAD_INFO-THREAD(r1); /* this thread's kernel stack */\
323 addi r1,r1,THREAD_SIZE; \
324 1: subi r1,r1,INT_FRAME_SIZE; /* Allocate an exception frame */\
326 stw r10,_CCR(r11); /* save various registers */\
327 stw r12,GPR12(r11); \
330 stw r10,GPR10(r11); \
332 stw r12,GPR11(r11); \
334 stw r10,_LINK(r11); \
340 rlwinm r9,r9,0,14,12; /* clear MSR_WE (necessary?) */\
342 SAVE_4GPRS(3, r11); \
346 * Exception prolog for critical exceptions. This is a little different
347 * from the normal exception prolog above since a critical exception
348 * can potentially occur at any point during normal exception processing.
349 * Thus we cannot use the same SPRG registers as the normal prolog above.
350 * Instead we use a couple of words of memory at low physical addresses.
351 * This is OK since we don't support SMP on these processors. For Book E
352 * processors, we also have a reserved register (SPRG2) that is only used
353 * in critical exceptions so we can free up a GPR to use as the base for
354 * indirect access to the critical exception save area. This is necessary
355 * since the MMU is always on and the save area is offset from KERNELBASE.
357 #define CRITICAL_EXCEPTION_PROLOG \
358 mtspr SPRG2,r8; /* SPRG2 only used in criticals */ \
359 lis r8,crit_save@ha; \
360 stw r10,crit_r10@l(r8); \
361 stw r11,crit_r11@l(r8); \
363 stw r10,crit_sprg0@l(r8); \
365 stw r10,crit_sprg1@l(r8); \
367 stw r10,crit_sprg4@l(r8); \
369 stw r10,crit_sprg5@l(r8); \
371 stw r10,crit_sprg7@l(r8); \
372 mfspr r10,SPRN_PID; \
373 stw r10,crit_pid@l(r8); \
375 stw r10,crit_srr0@l(r8); \
377 stw r10,crit_srr1@l(r8); \
378 mfspr r8,SPRG2; /* SPRG2 only used in criticals */ \
379 mfcr r10; /* save CR in r10 for now */\
380 mfspr r11,SPRN_CSRR1; /* check whether user or kernel */\
381 andi. r11,r11,MSR_PR; \
382 lis r11,critical_stack_top@h; \
383 ori r11,r11,critical_stack_top@l; \
385 /* COMING FROM USER MODE */ \
386 mfspr r11,SPRG3; /* if from user, start at top of */\
387 lwz r11,THREAD_INFO-THREAD(r11); /* this thread's kernel stack */\
388 addi r11,r11,THREAD_SIZE; \
389 1: subi r11,r11,INT_FRAME_SIZE; /* Allocate an exception frame */\
390 stw r10,_CCR(r11); /* save various registers */\
391 stw r12,GPR12(r11); \
394 stw r10,_LINK(r11); \
395 mfspr r12,SPRN_DEAR; /* save DEAR and ESR in the frame */\
396 stw r12,_DEAR(r11); /* since they may have had stuff */\
397 mfspr r9,SPRN_ESR; /* in them at the point where the */\
398 stw r9,_ESR(r11); /* exception was taken */\
404 rlwinm r9,r9,0,14,12; /* clear MSR_WE (necessary?) */\
406 SAVE_4GPRS(3, r11); \
410 * Exception prolog for machine check exceptions. This is similar to
411 * the critical exception prolog, except that machine check exceptions
412 * have their own save area. For Book E processors, we also have a
413 * reserved register (SPRG6) that is only used in machine check exceptions
414 * so we can free up a GPR to use as the base for indirect access to the
415 * machine check exception save area. This is necessary since the MMU
416 * is always on and the save area is offset from KERNELBASE.
418 #define MCHECK_EXCEPTION_PROLOG \
419 mtspr SPRG6W,r8; /* SPRG6 used in machine checks */ \
420 lis r8,mcheck_save@ha; \
421 stw r10,mcheck_r10@l(r8); \
422 stw r11,mcheck_r11@l(r8); \
424 stw r10,mcheck_sprg0@l(r8); \
426 stw r10,mcheck_sprg1@l(r8); \
428 stw r10,mcheck_sprg4@l(r8); \
430 stw r10,mcheck_sprg5@l(r8); \
432 stw r10,mcheck_sprg7@l(r8); \
433 mfspr r10,SPRN_PID; \
434 stw r10,mcheck_pid@l(r8); \
436 stw r10,mcheck_srr0@l(r8); \
438 stw r10,mcheck_srr1@l(r8); \
440 stw r10,mcheck_csrr0@l(r8); \
442 stw r10,mcheck_csrr1@l(r8); \
443 mfspr r8,SPRG6R; /* SPRG6 used in machine checks */ \
444 mfcr r10; /* save CR in r10 for now */\
445 mfspr r11,SPRN_MCSRR1; /* check whether user or kernel */\
446 andi. r11,r11,MSR_PR; \
447 lis r11,mcheck_stack_top@h; \
448 ori r11,r11,mcheck_stack_top@l; \
450 /* COMING FROM USER MODE */ \
451 mfspr r11,SPRG3; /* if from user, start at top of */\
452 lwz r11,THREAD_INFO-THREAD(r11); /* this thread's kernel stack */\
453 addi r11,r11,THREAD_SIZE; \
454 1: subi r11,r11,INT_FRAME_SIZE; /* Allocate an exception frame */\
455 stw r10,_CCR(r11); /* save various registers */\
456 stw r12,GPR12(r11); \
459 stw r10,_LINK(r11); \
460 mfspr r12,SPRN_DEAR; /* save DEAR and ESR in the frame */\
461 stw r12,_DEAR(r11); /* since they may have had stuff */\
462 mfspr r9,SPRN_ESR; /* in them at the point where the */\
463 stw r9,_ESR(r11); /* exception was taken */\
469 rlwinm r9,r9,0,14,12; /* clear MSR_WE (necessary?) */\
471 SAVE_4GPRS(3, r11); \
477 #define START_EXCEPTION(label) \
481 #define FINISH_EXCEPTION(func) \
482 bl transfer_to_handler_full; \
484 .long ret_from_except_full
486 #define EXCEPTION(n, label, hdlr, xfer) \
487 START_EXCEPTION(label); \
488 NORMAL_EXCEPTION_PROLOG; \
489 addi r3,r1,STACK_FRAME_OVERHEAD; \
492 #define CRITICAL_EXCEPTION(n, label, hdlr) \
493 START_EXCEPTION(label); \
494 CRITICAL_EXCEPTION_PROLOG; \
495 addi r3,r1,STACK_FRAME_OVERHEAD; \
496 EXC_XFER_TEMPLATE(hdlr, n+2, (MSR_KERNEL & ~(MSR_ME|MSR_DE|MSR_CE)), \
497 NOCOPY, transfer_to_handler_full, \
498 ret_from_except_full)
500 #define MCHECK_EXCEPTION(n, label, hdlr) \
501 START_EXCEPTION(label); \
502 MCHECK_EXCEPTION_PROLOG; \
504 mtspr SPRN_MCSR,r4; \
507 addi r3,r1,STACK_FRAME_OVERHEAD; \
508 EXC_XFER_TEMPLATE(hdlr, n+2, (MSR_KERNEL & ~(MSR_ME|MSR_DE|MSR_CE)), \
509 NOCOPY, mcheck_transfer_to_handler, \
512 #define EXC_XFER_TEMPLATE(hdlr, trap, msr, copyee, tfer, ret) \
522 #define COPY_EE(d, s) rlwimi d,s,0,16,16
525 #define EXC_XFER_STD(n, hdlr) \
526 EXC_XFER_TEMPLATE(hdlr, n, MSR_KERNEL, NOCOPY, transfer_to_handler_full, \
527 ret_from_except_full)
529 #define EXC_XFER_LITE(n, hdlr) \
530 EXC_XFER_TEMPLATE(hdlr, n+1, MSR_KERNEL, NOCOPY, transfer_to_handler, \
533 #define EXC_XFER_EE(n, hdlr) \
534 EXC_XFER_TEMPLATE(hdlr, n, MSR_KERNEL, COPY_EE, transfer_to_handler_full, \
535 ret_from_except_full)
537 #define EXC_XFER_EE_LITE(n, hdlr) \
538 EXC_XFER_TEMPLATE(hdlr, n+1, MSR_KERNEL, COPY_EE, transfer_to_handler, \
542 /* Critical Input Interrupt */
543 CRITICAL_EXCEPTION(0x0100, CriticalInput, UnknownException)
545 /* Machine Check Interrupt */
547 MCHECK_EXCEPTION(0x0200, MachineCheck, MachineCheckException)
549 CRITICAL_EXCEPTION(0x0200, MachineCheck, MachineCheckException)
552 /* Data Storage Interrupt */
553 START_EXCEPTION(DataStorage)
554 mtspr SPRG0, r10 /* Save some working registers */
562 * Check if it was a store fault, if not then bail
563 * because a user tried to access a kernel or
564 * read-protected page. Otherwise, get the
565 * offending address and handle it.
568 andis. r10, r10, ESR_ST@h
571 mfspr r10, SPRN_DEAR /* Get faulting address */
573 /* If we are faulting a kernel address, we have to use the
574 * kernel page tables.
576 andis. r11, r10, 0x8000
578 lis r11, swapper_pg_dir@h
579 ori r11, r11, swapper_pg_dir@l
582 rlwinm r12,r12,0,0,23 /* Clear TID */
586 /* Get the PGD for the current thread */
591 /* Load PID into MMUCR TID */
592 mfspr r12,SPRN_MMUCR /* Get MMUCR */
593 mfspr r13,SPRN_PID /* Get PID */
594 rlwimi r12,r13,0,24,31 /* Set TID */
599 rlwinm r12, r10, 13, 19, 29 /* Compute pgdir/pmd offset */
600 lwzx r11, r12, r11 /* Get pgd/pmd entry */
601 rlwinm. r12, r11, 0, 0, 20 /* Extract pt base address */
602 beq 2f /* Bail if no table */
604 rlwimi r12, r10, 23, 20, 28 /* Compute pte address */
605 lwz r11, 4(r12) /* Get pte entry */
607 andi. r13, r11, _PAGE_RW /* Is it writeable? */
608 beq 2f /* Bail if not */
612 ori r11, r11, _PAGE_DIRTY|_PAGE_ACCESSED|_PAGE_HWWRITE
613 stw r11, 4(r12) /* Update Linux page table */
615 li r13, PPC44x_TLB_SR@l /* Set SR */
616 rlwimi r13, r11, 29, 29, 29 /* SX = _PAGE_HWEXEC */
617 rlwimi r13, r11, 0, 30, 30 /* SW = _PAGE_RW */
618 rlwimi r13, r11, 29, 28, 28 /* UR = _PAGE_USER */
619 rlwimi r12, r11, 31, 26, 26 /* (_PAGE_USER>>1)->r12 */
620 rlwimi r12, r11, 29, 30, 30 /* (_PAGE_USER>>3)->r12 */
621 and r12, r12, r11 /* HWEXEC/RW & USER */
622 rlwimi r13, r12, 0, 26, 26 /* UX = HWEXEC & USER */
623 rlwimi r13, r12, 3, 27, 27 /* UW = RW & USER */
625 rlwimi r11,r13,0,26,31 /* Insert static perms */
627 rlwinm r11,r11,0,20,15 /* Clear U0-U3 */
629 /* find the TLB index that caused the fault. It has to be here. */
632 tlbwe r11, r10, PPC44x_TLB_ATTRIB /* Write ATTRIB */
634 /* Done...restore registers and get out of here.
643 rfi /* Force context change */
647 * The bailout. Restore registers to pre-exception conditions
648 * and call the heavyweights to help us out.
659 /* Instruction Storage Interrupt */
660 START_EXCEPTION(InstructionStorage)
661 NORMAL_EXCEPTION_PROLOG
662 mr r4,r12 /* Pass SRR0 as arg2 */
663 li r5,0 /* Pass zero as arg3 */
664 EXC_XFER_EE_LITE(0x0400, handle_page_fault)
666 /* External Input Interrupt */
667 EXCEPTION(0x0500, ExternalInput, do_IRQ, EXC_XFER_LITE)
669 /* Alignment Interrupt */
670 START_EXCEPTION(Alignment)
671 NORMAL_EXCEPTION_PROLOG
672 mfspr r4,SPRN_DEAR /* Grab the DEAR and save it */
674 addi r3,r1,STACK_FRAME_OVERHEAD
675 EXC_XFER_EE(0x0600, AlignmentException)
677 /* Program Interrupt */
678 START_EXCEPTION(Program)
679 NORMAL_EXCEPTION_PROLOG
680 mfspr r4,SPRN_ESR /* Grab the ESR and save it */
682 addi r3,r1,STACK_FRAME_OVERHEAD
683 EXC_XFER_EE(0x700, ProgramCheckException)
685 /* Floating Point Unavailable Interrupt */
686 EXCEPTION(0x2010, FloatingPointUnavailable, UnknownException, EXC_XFER_EE)
688 /* System Call Interrupt */
689 START_EXCEPTION(SystemCall)
690 NORMAL_EXCEPTION_PROLOG
691 EXC_XFER_EE_LITE(0x0c00, DoSyscall)
693 /* Auxillary Processor Unavailable Interrupt */
694 EXCEPTION(0x2020, AuxillaryProcessorUnavailable, UnknownException, EXC_XFER_EE)
696 /* Decrementer Interrupt */
697 START_EXCEPTION(Decrementer)
698 NORMAL_EXCEPTION_PROLOG
699 lis r0,TSR_DIS@h /* Setup the DEC interrupt mask */
700 mtspr SPRN_TSR,r0 /* Clear the DEC interrupt */
701 addi r3,r1,STACK_FRAME_OVERHEAD
702 EXC_XFER_LITE(0x1000, timer_interrupt)
704 /* Fixed Internal Timer Interrupt */
705 /* TODO: Add FIT support */
706 EXCEPTION(0x1010, FixedIntervalTimer, UnknownException, EXC_XFER_EE)
708 /* Watchdog Timer Interrupt */
709 /* TODO: Add watchdog support */
710 CRITICAL_EXCEPTION(0x1020, WatchdogTimer, UnknownException)
712 /* Data TLB Error Interrupt */
713 START_EXCEPTION(DataTLBError)
714 mtspr SPRG0, r10 /* Save some working registers */
720 mfspr r10, SPRN_DEAR /* Get faulting address */
722 /* If we are faulting a kernel address, we have to use the
723 * kernel page tables.
725 andis. r11, r10, 0x8000
727 lis r11, swapper_pg_dir@h
728 ori r11, r11, swapper_pg_dir@l
731 rlwinm r12,r12,0,0,23 /* Clear TID */
735 /* Get the PGD for the current thread */
740 /* Load PID into MMUCR TID */
742 mfspr r13,SPRN_PID /* Get PID */
743 rlwimi r12,r13,0,24,31 /* Set TID */
748 rlwinm r12, r10, 13, 19, 29 /* Compute pgdir/pmd offset */
749 lwzx r11, r12, r11 /* Get pgd/pmd entry */
750 rlwinm. r12, r11, 0, 0, 20 /* Extract pt base address */
751 beq 2f /* Bail if no table */
753 rlwimi r12, r10, 23, 20, 28 /* Compute pte address */
754 lwz r11, 4(r12) /* Get pte entry */
755 andi. r13, r11, _PAGE_PRESENT /* Is the page present? */
756 beq 2f /* Bail if not present */
758 ori r11, r11, _PAGE_ACCESSED
761 /* Jump to common tlb load */
765 /* The bailout. Restore registers to pre-exception conditions
766 * and call the heavyweights to help us out.
776 /* Instruction TLB Error Interrupt */
778 * Nearly the same as above, except we get our
779 * information from different registers and bailout
780 * to a different point.
782 START_EXCEPTION(InstructionTLBError)
783 mtspr SPRG0, r10 /* Save some working registers */
789 mfspr r10, SRR0 /* Get faulting address */
791 /* If we are faulting a kernel address, we have to use the
792 * kernel page tables.
794 andis. r11, r10, 0x8000
796 lis r11, swapper_pg_dir@h
797 ori r11, r11, swapper_pg_dir@l
800 rlwinm r12,r12,0,0,23 /* Clear TID */
804 /* Get the PGD for the current thread */
809 /* Load PID into MMUCR TID */
811 mfspr r13,SPRN_PID /* Get PID */
812 rlwimi r12,r13,0,24,31 /* Set TID */
817 rlwinm r12, r10, 13, 19, 29 /* Compute pgdir/pmd offset */
818 lwzx r11, r12, r11 /* Get pgd/pmd entry */
819 rlwinm. r12, r11, 0, 0, 20 /* Extract pt base address */
820 beq 2f /* Bail if no table */
822 rlwimi r12, r10, 23, 20, 28 /* Compute pte address */
823 lwz r11, 4(r12) /* Get pte entry */
824 andi. r13, r11, _PAGE_PRESENT /* Is the page present? */
825 beq 2f /* Bail if not present */
827 ori r11, r11, _PAGE_ACCESSED
830 /* Jump to common TLB load point */
834 /* The bailout. Restore registers to pre-exception conditions
835 * and call the heavyweights to help us out.
845 /* Check for a single step debug exception while in an exception
846 * handler before state has been saved. This is to catch the case
847 * where an instruction that we are trying to single step causes
848 * an exception (eg ITLB/DTLB miss) and thus the first instruction of
849 * the exception handler generates a single step debug exception.
851 * If we get a debug trap on the first instruction of an exception handler,
852 * we reset the MSR_DE in the _exception handler's_ MSR (the debug trap is
853 * a critical exception, so we are using SPRN_CSRR1 to manipulate the MSR).
854 * The exception handler was handling a non-critical interrupt, so it will
855 * save (and later restore) the MSR via SPRN_SRR1, which will still have
856 * the MSR_DE bit set.
858 /* Debug Interrupt */
859 START_EXCEPTION(Debug)
860 CRITICAL_EXCEPTION_PROLOG
863 * If this is a single step or branch-taken exception in an
864 * exception entry sequence, it was probably meant to apply to
865 * the code where the exception occurred (since exception entry
866 * doesn't turn off DE automatically). We simulate the effect
867 * of turning off DE on entry to an exception handler by turning
868 * off DE in the CSRR1 value and clearing the debug status.
870 mfspr r10,SPRN_DBSR /* check single-step/branch taken */
871 andis. r10,r10,(DBSR_IC|DBSR_BT)@h
873 andi. r0,r9,MSR_PR /* check supervisor */
874 beq 2f /* branch if we need to fix it up... */
876 /* continue normal handling for a critical exception... */
877 1: mfspr r4,SPRN_DBSR
878 addi r3,r1,STACK_FRAME_OVERHEAD
879 EXC_XFER_TEMPLATE(DebugException, 0x2002, \
880 (MSR_KERNEL & ~(MSR_ME|MSR_DE|MSR_CE)), \
881 NOCOPY, crit_transfer_to_handler, ret_from_crit_exc)
883 /* here it looks like we got an inappropriate debug exception. */
884 2: rlwinm r9,r9,0,~MSR_DE /* clear DE in the CSRR1 value */
885 mtspr SPRN_DBSR,r10 /* clear the IC/BT debug intr status */
886 /* restore state and get out */
895 mtspr SPRG2,r8; /* SPRG2 only used in criticals */
897 lwz r10,crit_r10@l(r8)
898 lwz r11,crit_r11@l(r8)
908 * Data TLB exceptions will bail out to this point
909 * if they can't resolve the lightweight TLB fault.
912 NORMAL_EXCEPTION_PROLOG
913 mfspr r5,SPRN_ESR /* Grab the ESR, save it, pass arg3 */
915 mfspr r4,SPRN_DEAR /* Grab the DEAR, save it, pass arg2 */
916 EXC_XFER_EE_LITE(0x0300, handle_page_fault)
920 * Both the instruction and data TLB miss get to this
921 * point to load the TLB.
923 * r11 - available to use
924 * r12 - Pointer to the 64-bit PTE
925 * r13 - available to use
926 * MMUCR - loaded with proper value when we get here
927 * Upon exit, we reload everything and RFI.
931 * We set execute, because we don't have the granularity to
932 * properly set this at the page level (Linux problem).
933 * If shared is set, we cause a zero PID->TID load.
934 * Many of these bits are software only. Bits we don't set
935 * here we (properly should) assume have the appropriate value.
938 /* Load the next available TLB index */
939 lis r13, tlb_44x_index@ha
940 lwz r13, tlb_44x_index@l(r13)
941 /* Load the TLB high watermark */
942 lis r11, tlb_44x_hwater@ha
943 lwz r11, tlb_44x_hwater@l(r11)
945 /* Increment, rollover, and store TLB index */
947 cmpw 0, r13, r11 /* reserve entries */
951 /* Store the next available TLB index */
952 lis r11, tlb_44x_index@ha
953 stw r13, tlb_44x_index@l(r11)
955 lwz r11, 0(r12) /* Get MS word of PTE */
956 lwz r12, 4(r12) /* Get LS word of PTE */
957 rlwimi r11, r12, 0, 0 , 19 /* Insert RPN */
958 tlbwe r11, r13, PPC44x_TLB_XLAT /* Write XLAT */
961 * Create PAGEID. This is the faulting address,
962 * page size, and valid flag.
964 li r11, PPC44x_TLB_VALID | PPC44x_TLB_4K
965 rlwimi r10, r11, 0, 20, 31 /* Insert valid and page size */
966 tlbwe r10, r13, PPC44x_TLB_PAGEID /* Write PAGEID */
968 li r10, PPC44x_TLB_SR@l /* Set SR */
969 rlwimi r10, r12, 0, 30, 30 /* Set SW = _PAGE_RW */
970 rlwimi r10, r12, 29, 29, 29 /* SX = _PAGE_HWEXEC */
971 rlwimi r10, r12, 29, 28, 28 /* UR = _PAGE_USER */
972 rlwimi r11, r12, 31, 26, 26 /* (_PAGE_USER>>1)->r12 */
973 and r11, r12, r11 /* HWEXEC & USER */
974 rlwimi r10, r11, 0, 26, 26 /* UX = HWEXEC & USER */
976 rlwimi r12, r10, 0, 26, 31 /* Insert static perms */
977 rlwinm r12, r12, 0, 20, 15 /* Clear U0-U3 */
978 tlbwe r12, r13, PPC44x_TLB_ATTRIB /* Write ATTRIB */
980 /* Done...restore registers and get out of here.
988 rfi /* Force context change */
995 * extern void giveup_altivec(struct task_struct *prev)
997 * The 44x core does not have an AltiVec unit.
999 _GLOBAL(giveup_altivec)
1003 * extern void giveup_fpu(struct task_struct *prev)
1005 * The 44x core does not have an FPU.
1011 * extern void abort(void)
1013 * At present, this routine just applies a system reset.
1016 mfspr r13,SPRN_DBCR0
1017 oris r13,r13,DBCR0_RST_SYSTEM@h
1018 mtspr SPRN_DBCR0,r13
1020 _GLOBAL(set_context)
1022 #ifdef CONFIG_BDI_SWITCH
1023 /* Context switch the PTE pointer for the Abatron BDI2000.
1024 * The PGDIR is the second parameter.
1026 lis r5, abatron_pteptrs@h
1027 ori r5, r5, abatron_pteptrs@l
1031 isync /* Force context change */
1035 * We put a few things here that have to be page-aligned. This stuff
1036 * goes at the beginning of the data segment, which is page-aligned.
1040 _GLOBAL(empty_zero_page)
1044 * To support >32-bit physical addresses, we use an 8KB pgdir.
1046 _GLOBAL(swapper_pg_dir)
1050 /* Stack for handling critical exceptions from kernel mode */
1051 critical_stack_bottom:
1056 /* Stack for handling machine check exceptions from kernel mode */
1057 mcheck_stack_bottom:
1063 * This area is used for temporarily saving registers during the
1064 * critical and machine check exception prologs. It must always
1065 * follow the page aligned allocations, so it starts on a page
1066 * boundary, ensuring that all crit_save areas are in a single
1095 _GLOBAL(mcheck_save)
1101 _GLOBAL(mcheck_sprg0)
1103 _GLOBAL(mcheck_sprg1)
1105 _GLOBAL(mcheck_sprg4)
1107 _GLOBAL(mcheck_sprg5)
1109 _GLOBAL(mcheck_sprg7)
1113 _GLOBAL(mcheck_srr0)
1115 _GLOBAL(mcheck_srr1)
1117 _GLOBAL(mcheck_csrr0)
1119 _GLOBAL(mcheck_csrr1)
1123 * This space gets a copy of optional info passed to us by the bootstrap
1124 * which is used to pass parameters into the kernel like root=/dev/sda1, etc.
1130 * Room for two PTE pointers, usually the kernel and current user pointers
1131 * to their respective root page table.