3 * Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
4 * Rewritten by Cort Dougan (cort@cs.nmt.edu) for PReP
5 * Copyright (C) 1996 Cort Dougan <cort@cs.nmt.edu>
6 * Low-level exception handlers and MMU support
7 * rewritten by Paul Mackerras.
8 * Copyright (C) 1996 Paul Mackerras.
9 * MPC8xx modifications by Dan Malek
10 * Copyright (C) 1997 Dan Malek (dmalek@jlc.net).
12 * This file contains low-level support and setup for PowerPC 8xx
13 * embedded processors, including trap and interrupt dispatch.
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.
22 #include <linux/init.h>
23 #include <asm/processor.h>
26 #include <asm/cache.h>
27 #include <asm/pgtable.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/ptrace.h>
34 /* Macro to make the code more readable. */
35 #ifdef CONFIG_8xx_CPU6
36 #define SPRN_MI_TWC_ADDR 0x2b80
37 #define SPRN_MI_RPN_ADDR 0x2d80
38 #define SPRN_MD_TWC_ADDR 0x3b80
39 #define SPRN_MD_RPN_ADDR 0x3d80
41 #define MTSPR_CPU6(spr, reg, treg) \
42 li treg, spr##_ADDR; \
47 #define MTSPR_CPU6(spr, reg, treg) \
52 * Value for the bits that have fixed value in RPN entries.
53 * Also used for tagging DAR for DTLBerror.
55 #ifdef CONFIG_PPC_16K_PAGES
56 #define RPN_PATTERN (0x00f0 | MD_SPS16K)
58 #define RPN_PATTERN 0x00f0
66 * This port was done on an MBX board with an 860. Right now I only
67 * support an ELF compressed (zImage) boot from EPPC-Bug because the
68 * code there loads up some registers before calling us:
69 * r3: ptr to board info data
70 * r4: initrd_start or if no initrd then 0
71 * r5: initrd_end - unused if r4 is 0
72 * r6: Start of command line string
73 * r7: End of command line string
75 * I decided to use conditional compilation instead of checking PVR and
76 * adding more processor specific branches around code I don't need.
77 * Since this is an embedded processor, I also appreciate any memory
80 * The MPC8xx does not have any BATs, but it supports large page sizes.
81 * We first initialize the MMU to support 8M byte pages, then load one
82 * entry into each of the instruction and data TLBs to map the first
83 * 8M 1:1. I also mapped an additional I/O space 1:1 so we can get to
84 * the "internal" processor registers before MMU_init is called.
90 mr r31,r3 /* save device tree ptr */
92 /* We have to turn on the MMU right away so we get cache modes
97 /* We now have the lower 8 Meg mapped into TLB entries, and the caches
103 ori r0,r0,MSR_DR|MSR_IR
106 ori r0,r0,start_here@l
109 rfi /* enables MMU */
112 * Exception entry code. This code runs with address translation
113 * turned off, i.e. using physical addresses.
114 * We assume sprg3 has the physical address of the current
115 * task's thread_struct.
117 #define EXCEPTION_PROLOG \
118 EXCEPTION_PROLOG_0; \
120 EXCEPTION_PROLOG_1; \
123 #define EXCEPTION_PROLOG_0 \
124 mtspr SPRN_SPRG_SCRATCH0,r10; \
125 mtspr SPRN_SPRG_SCRATCH1,r11
127 #define EXCEPTION_PROLOG_1 \
128 mfspr r11,SPRN_SRR1; /* check whether user or kernel */ \
129 andi. r11,r11,MSR_PR; \
130 tophys(r11,r1); /* use tophys(r1) if kernel */ \
132 mfspr r11,SPRN_SPRG_THREAD; \
133 lwz r11,THREAD_INFO-THREAD(r11); \
134 addi r11,r11,THREAD_SIZE; \
136 1: subi r11,r11,INT_FRAME_SIZE /* alloc exc. frame */
139 #define EXCEPTION_PROLOG_2 \
141 stw r10,_CCR(r11); /* save registers */ \
142 stw r12,GPR12(r11); \
144 mfspr r10,SPRN_SPRG_SCRATCH0; \
145 stw r10,GPR10(r11); \
146 mfspr r12,SPRN_SPRG_SCRATCH1; \
147 stw r12,GPR11(r11); \
149 stw r10,_LINK(r11); \
150 mfspr r12,SPRN_SRR0; \
151 mfspr r9,SPRN_SRR1; \
154 tovirt(r1,r11); /* set new kernel sp */ \
155 li r10,MSR_KERNEL & ~(MSR_IR|MSR_DR); /* can take exceptions */ \
156 MTMSRD(r10); /* (except for mach check in rtas) */ \
158 SAVE_4GPRS(3, r11); \
162 * Exception exit code.
164 #define EXCEPTION_EPILOG_0 \
165 mfspr r10,SPRN_SPRG_SCRATCH0; \
166 mfspr r11,SPRN_SPRG_SCRATCH1
169 * Note: code which follows this uses cr0.eq (set if from kernel),
170 * r11, r12 (SRR0), and r9 (SRR1).
172 * Note2: once we have set r1 we are in a position to take exceptions
173 * again, and we could thus set MSR:RI at that point.
179 #define EXCEPTION(n, label, hdlr, xfer) \
183 addi r3,r1,STACK_FRAME_OVERHEAD; \
186 #define EXC_XFER_TEMPLATE(n, hdlr, trap, copyee, tfer, ret) \
188 stw r10,_TRAP(r11); \
196 #define COPY_EE(d, s) rlwimi d,s,0,16,16
199 #define EXC_XFER_STD(n, hdlr) \
200 EXC_XFER_TEMPLATE(n, hdlr, n, NOCOPY, transfer_to_handler_full, \
201 ret_from_except_full)
203 #define EXC_XFER_LITE(n, hdlr) \
204 EXC_XFER_TEMPLATE(n, hdlr, n+1, NOCOPY, transfer_to_handler, \
207 #define EXC_XFER_EE(n, hdlr) \
208 EXC_XFER_TEMPLATE(n, hdlr, n, COPY_EE, transfer_to_handler_full, \
209 ret_from_except_full)
211 #define EXC_XFER_EE_LITE(n, hdlr) \
212 EXC_XFER_TEMPLATE(n, hdlr, n+1, COPY_EE, transfer_to_handler, \
216 EXCEPTION(0x100, Reset, unknown_exception, EXC_XFER_STD)
225 mtspr SPRN_DAR,r5 /* Tag DAR, to be used in DTLB Error */
228 addi r3,r1,STACK_FRAME_OVERHEAD
229 EXC_XFER_STD(0x200, machine_check_exception)
231 /* Data access exception.
232 * This is "never generated" by the MPC8xx.
237 /* Instruction access exception.
238 * This is "never generated" by the MPC8xx.
243 /* External interrupt */
244 EXCEPTION(0x500, HardwareInterrupt, do_IRQ, EXC_XFER_LITE)
246 /* Alignment exception */
253 mtspr SPRN_DAR,r5 /* Tag DAR, to be used in DTLB Error */
256 addi r3,r1,STACK_FRAME_OVERHEAD
257 EXC_XFER_EE(0x600, alignment_exception)
259 /* Program check exception */
260 EXCEPTION(0x700, ProgramCheck, program_check_exception, EXC_XFER_STD)
262 /* No FPU on MPC8xx. This exception is not supposed to happen.
264 EXCEPTION(0x800, FPUnavailable, unknown_exception, EXC_XFER_STD)
267 EXCEPTION(0x900, Decrementer, timer_interrupt, EXC_XFER_LITE)
269 EXCEPTION(0xa00, Trap_0a, unknown_exception, EXC_XFER_EE)
270 EXCEPTION(0xb00, Trap_0b, unknown_exception, EXC_XFER_EE)
276 EXC_XFER_EE_LITE(0xc00, DoSyscall)
278 /* Single step - not used on 601 */
279 EXCEPTION(0xd00, SingleStep, single_step_exception, EXC_XFER_STD)
280 EXCEPTION(0xe00, Trap_0e, unknown_exception, EXC_XFER_EE)
281 EXCEPTION(0xf00, Trap_0f, unknown_exception, EXC_XFER_EE)
283 /* On the MPC8xx, this is a software emulation interrupt. It occurs
284 * for all unimplemented and illegal instructions.
286 EXCEPTION(0x1000, SoftEmu, SoftwareEmulation, EXC_XFER_STD)
290 * For the MPC8xx, this is a software tablewalk to load the instruction
291 * TLB. The task switch loads the M_TW register with the pointer to the first
293 * If we discover there is no second level table (value is zero) or if there
294 * is an invalid pte, we load that into the TLB, which causes another fault
295 * into the TLB Error interrupt where we can handle such problems.
296 * We have to use the MD_xxx registers for the tablewalk because the
297 * equivalent MI_xxx registers only perform the attribute functions.
300 #ifdef CONFIG_8xx_CPU15
301 #define INVALIDATE_ADJACENT_PAGES_CPU15(tmp, addr) \
302 addi tmp, addr, PAGE_SIZE; \
304 addi tmp, addr, -PAGE_SIZE; \
307 #define INVALIDATE_ADJACENT_PAGES_CPU15(tmp, addr)
311 #ifdef CONFIG_8xx_CPU6
312 mtspr SPRN_SPRG_SCRATCH2, r3
316 /* If we are faulting a kernel address, we have to use the
317 * kernel page tables.
319 #ifdef CONFIG_MODULES
320 /* Only modules will cause ITLB Misses as we always
321 * pin the first 8MB of kernel memory */
322 mfspr r11, SPRN_SRR0 /* Get effective address of fault */
323 INVALIDATE_ADJACENT_PAGES_CPU15(r10, r11)
325 andis. r11, r11, 0x8000 /* Address >= 0x80000000 */
326 mfspr r11, SPRN_M_TW /* Get level 1 table */
328 lis r11, (swapper_pg_dir-PAGE_OFFSET)@ha
331 mfspr r10, SPRN_SRR0 /* Get effective address of fault */
333 mfspr r10, SPRN_SRR0 /* Get effective address of fault */
334 INVALIDATE_ADJACENT_PAGES_CPU15(r11, r10)
335 mfspr r11, SPRN_M_TW /* Get level 1 table base address */
337 /* Insert level 1 index */
338 rlwimi r11, r10, 32 - ((PAGE_SHIFT - 2) << 1), (PAGE_SHIFT - 2) << 1, 29
339 lwz r11, (swapper_pg_dir-PAGE_OFFSET)@l(r11) /* Get the level 1 entry */
341 /* Load the MI_TWC with the attributes for this "segment." */
342 MTSPR_CPU6(SPRN_MI_TWC, r11, r3) /* Set segment attributes */
343 rlwinm r11, r11,0,0,19 /* Extract page descriptor page address */
344 /* Extract level 2 index */
345 rlwinm r10, r10, 32 - (PAGE_SHIFT - 2), 32 - PAGE_SHIFT, 29
346 lwzx r10, r10, r11 /* Get the pte */
349 rlwinm r11, r10, 32-5, _PAGE_PRESENT
351 rlwimi r10, r11, 0, _PAGE_PRESENT
354 /* The Linux PTE won't go exactly into the MMU TLB.
355 * Software indicator bits 21 and 28 must be clear.
356 * Software indicator bits 24, 25, 26, and 27 must be
357 * set. All other Linux PTE bits control the behavior
360 rlwimi r10, r11, 0, 0x07f8 /* Set 24-27, clear 21-23,28 */
361 MTSPR_CPU6(SPRN_MI_RPN, r10, r3) /* Update TLB entry */
363 /* Restore registers */
364 #ifdef CONFIG_8xx_CPU6
365 mfspr r3, SPRN_SPRG_SCRATCH2
372 #ifdef CONFIG_8xx_CPU6
373 mtspr SPRN_SPRG_SCRATCH2, r3
378 /* If we are faulting a kernel address, we have to use the
379 * kernel page tables.
381 mfspr r11, SPRN_MD_EPN
382 andis. r11, r11, 0x8000
383 mfspr r11, SPRN_M_TW /* Get level 1 table */
385 lis r11, (swapper_pg_dir-PAGE_OFFSET)@ha
388 mfspr r10, SPRN_MD_EPN
390 /* Insert level 1 index */
391 rlwimi r11, r10, 32 - ((PAGE_SHIFT - 2) << 1), (PAGE_SHIFT - 2) << 1, 29
392 lwz r11, (swapper_pg_dir-PAGE_OFFSET)@l(r11) /* Get the level 1 entry */
394 /* We have a pte table, so load fetch the pte from the table.
396 /* Extract level 2 index */
397 rlwinm r10, r10, 32 - (PAGE_SHIFT - 2), 32 - PAGE_SHIFT, 29
398 rlwimi r10, r11, 0, 0, 32 - PAGE_SHIFT - 1 /* Add level 2 base */
399 lwz r10, 0(r10) /* Get the pte */
401 /* Insert the Guarded flag into the TWC from the Linux PTE.
402 * It is bit 27 of both the Linux PTE and the TWC (at least
403 * I got that right :-). It will be better when we can put
404 * this into the Linux pgd/pmd and load it in the operation
407 rlwimi r11, r10, 0, 27, 27
408 /* Insert the WriteThru flag into the TWC from the Linux PTE.
409 * It is bit 25 in the Linux PTE and bit 30 in the TWC
411 rlwimi r11, r10, 32-5, 30, 30
412 MTSPR_CPU6(SPRN_MD_TWC, r11, r3)
414 /* Both _PAGE_ACCESSED and _PAGE_PRESENT has to be set.
415 * We also need to know if the insn is a load/store, so:
416 * Clear _PAGE_PRESENT and load that which will
417 * trap into DTLB Error with store bit set accordinly.
419 /* PRESENT=0x1, ACCESSED=0x20
420 * r11 = ((r10 & PRESENT) & ((r10 & ACCESSED) >> 5));
421 * r10 = (r10 & ~PRESENT) | r11;
424 rlwinm r11, r10, 32-5, _PAGE_PRESENT
426 rlwimi r10, r11, 0, _PAGE_PRESENT
428 /* The Linux PTE won't go exactly into the MMU TLB.
429 * Software indicator bits 22 and 28 must be clear.
430 * Software indicator bits 24, 25, 26, and 27 must be
431 * set. All other Linux PTE bits control the behavior
435 rlwimi r10, r11, 0, 24, 28 /* Set 24-27, clear 28 */
436 MTSPR_CPU6(SPRN_MD_RPN, r10, r3) /* Update TLB entry */
438 /* Restore registers */
439 #ifdef CONFIG_8xx_CPU6
440 mfspr r3, SPRN_SPRG_SCRATCH2
442 mtspr SPRN_DAR, r11 /* Tag DAR */
446 /* This is an instruction TLB error on the MPC8xx. This could be due
447 * to many reasons, such as executing guarded memory or illegal instruction
448 * addresses. There is nothing to do but handle a big time error fault.
458 /* 0x400 is InstructionAccess exception, needed by bad_page_fault() */
459 1: EXC_XFER_LITE(0x400, handle_page_fault)
461 /* This is the data TLB error on the MPC8xx. This could be due to
462 * many reasons, including a dirty update to a pte. We bail out to
463 * a higher level function that can handle it.
471 cmpwi cr0, r11, RPN_PATTERN
472 beq- FixupDAR /* must be a buggy dcbX, icbi insn. */
473 DARFixed:/* Return from dcbx instruction bug workaround */
482 1: li r10,RPN_PATTERN
483 mtspr SPRN_DAR,r10 /* Tag DAR, to be used in DTLB Error */
484 /* 0x300 is DataAccess exception, needed by bad_page_fault() */
485 EXC_XFER_LITE(0x300, handle_page_fault)
487 EXCEPTION(0x1500, Trap_15, unknown_exception, EXC_XFER_EE)
488 EXCEPTION(0x1600, Trap_16, unknown_exception, EXC_XFER_EE)
489 EXCEPTION(0x1700, Trap_17, unknown_exception, EXC_XFER_EE)
490 EXCEPTION(0x1800, Trap_18, unknown_exception, EXC_XFER_EE)
491 EXCEPTION(0x1900, Trap_19, unknown_exception, EXC_XFER_EE)
492 EXCEPTION(0x1a00, Trap_1a, unknown_exception, EXC_XFER_EE)
493 EXCEPTION(0x1b00, Trap_1b, unknown_exception, EXC_XFER_EE)
495 /* On the MPC8xx, these next four traps are used for development
496 * support of breakpoints and such. Someday I will get around to
499 EXCEPTION(0x1c00, Trap_1c, unknown_exception, EXC_XFER_EE)
500 EXCEPTION(0x1d00, Trap_1d, unknown_exception, EXC_XFER_EE)
501 EXCEPTION(0x1e00, Trap_1e, unknown_exception, EXC_XFER_EE)
502 EXCEPTION(0x1f00, Trap_1f, unknown_exception, EXC_XFER_EE)
506 /* This is the procedure to calculate the data EA for buggy dcbx,dcbi instructions
507 * by decoding the registers used by the dcbx instruction and adding them.
508 * DAR is set to the calculated address.
510 /* define if you don't want to use self modifying code */
511 #define NO_SELF_MODIFYING_CODE
512 FixupDAR:/* Entry point for dcbx workaround. */
513 mtspr SPRN_SPRG_SCRATCH2, r10
514 /* fetch instruction from memory. */
516 andis. r11, r10, 0x8000 /* Address >= 0x80000000 */
517 mfspr r11, SPRN_M_TW /* Get level 1 table */
519 lis r11, (swapper_pg_dir-PAGE_OFFSET)@ha
520 /* Insert level 1 index */
521 3: rlwimi r11, r10, 32 - ((PAGE_SHIFT - 2) << 1), (PAGE_SHIFT - 2) << 1, 29
522 lwz r11, (swapper_pg_dir-PAGE_OFFSET)@l(r11) /* Get the level 1 entry */
523 rlwinm r11, r11,0,0,19 /* Extract page descriptor page address */
524 /* Insert level 2 index */
525 rlwimi r11, r10, 32 - (PAGE_SHIFT - 2), 32 - PAGE_SHIFT, 29
526 lwz r11, 0(r11) /* Get the pte */
527 /* concat physical page address(r11) and page offset(r10) */
528 rlwimi r11, r10, 0, 32 - PAGE_SHIFT, 31
530 /* Check if it really is a dcbx instruction. */
531 /* dcbt and dcbtst does not generate DTLB Misses/Errors,
532 * no need to include them here */
533 xoris r10, r11, 0x7c00 /* check if major OP code is 31 */
534 rlwinm r10, r10, 0, 21, 5
535 cmpwi cr0, r10, 2028 /* Is dcbz? */
537 cmpwi cr0, r10, 940 /* Is dcbi? */
539 cmpwi cr0, r10, 108 /* Is dcbst? */
540 beq+ 144f /* Fix up store bit! */
541 cmpwi cr0, r10, 172 /* Is dcbf? */
543 cmpwi cr0, r10, 1964 /* Is icbi? */
545 141: mfspr r10,SPRN_SPRG_SCRATCH2
546 b DARFixed /* Nope, go back to normal TLB processing */
548 144: mfspr r10, SPRN_DSISR
549 rlwinm r10, r10,0,7,5 /* Clear store bit for buggy dcbst insn */
550 mtspr SPRN_DSISR, r10
551 142: /* continue, it was a dcbx, dcbi instruction. */
552 #ifndef NO_SELF_MODIFYING_CODE
553 andis. r10,r11,0x1f /* test if reg RA is r0 */
554 li r10,modified_instr@l
555 dcbtst r0,r10 /* touch for store */
556 rlwinm r11,r11,0,0,20 /* Zero lower 10 bits */
557 oris r11,r11,640 /* Transform instr. to a "add r10,RA,RB" */
559 stw r11,0(r10) /* store add/and instruction */
560 dcbf 0,r10 /* flush new instr. to memory. */
561 icbi 0,r10 /* invalidate instr. cache line */
562 mfspr r11, SPRN_SPRG_SCRATCH1 /* restore r11 */
563 mfspr r10, SPRN_SPRG_SCRATCH0 /* restore r10 */
564 isync /* Wait until new instr is loaded from memory */
566 .space 4 /* this is where the add instr. is stored */
568 subf r10,r0,r10 /* r10=r10-r0, only if reg RA is r0 */
569 143: mtdar r10 /* store faulting EA in DAR */
570 mfspr r10,SPRN_SPRG_SCRATCH2
571 b DARFixed /* Go back to normal TLB handling */
574 mtdar r10 /* save ctr reg in DAR */
575 rlwinm r10, r11, 24, 24, 28 /* offset into jump table for reg RB */
576 addi r10, r10, 150f@l /* add start of table */
577 mtctr r10 /* load ctr with jump address */
578 xor r10, r10, r10 /* sum starts at zero */
579 bctr /* jump into table */
581 add r10, r10, r0 ;b 151f
582 add r10, r10, r1 ;b 151f
583 add r10, r10, r2 ;b 151f
584 add r10, r10, r3 ;b 151f
585 add r10, r10, r4 ;b 151f
586 add r10, r10, r5 ;b 151f
587 add r10, r10, r6 ;b 151f
588 add r10, r10, r7 ;b 151f
589 add r10, r10, r8 ;b 151f
590 add r10, r10, r9 ;b 151f
591 mtctr r11 ;b 154f /* r10 needs special handling */
592 mtctr r11 ;b 153f /* r11 needs special handling */
593 add r10, r10, r12 ;b 151f
594 add r10, r10, r13 ;b 151f
595 add r10, r10, r14 ;b 151f
596 add r10, r10, r15 ;b 151f
597 add r10, r10, r16 ;b 151f
598 add r10, r10, r17 ;b 151f
599 add r10, r10, r18 ;b 151f
600 add r10, r10, r19 ;b 151f
601 add r10, r10, r20 ;b 151f
602 add r10, r10, r21 ;b 151f
603 add r10, r10, r22 ;b 151f
604 add r10, r10, r23 ;b 151f
605 add r10, r10, r24 ;b 151f
606 add r10, r10, r25 ;b 151f
607 add r10, r10, r26 ;b 151f
608 add r10, r10, r27 ;b 151f
609 add r10, r10, r28 ;b 151f
610 add r10, r10, r29 ;b 151f
611 add r10, r10, r30 ;b 151f
614 rlwinm. r11,r11,19,24,28 /* offset into jump table for reg RA */
615 beq 152f /* if reg RA is zero, don't add it */
616 addi r11, r11, 150b@l /* add start of table */
617 mtctr r11 /* load ctr with jump address */
618 rlwinm r11,r11,0,16,10 /* make sure we don't execute this more than once */
619 bctr /* jump into table */
622 mtctr r11 /* restore ctr reg from DAR */
623 mtdar r10 /* save fault EA to DAR */
624 mfspr r10,SPRN_SPRG_SCRATCH2
625 b DARFixed /* Go back to normal TLB handling */
627 /* special handling for r10,r11 since these are modified already */
628 153: mfspr r11, SPRN_SPRG_SCRATCH1 /* load r11 from SPRN_SPRG_SCRATCH1 */
629 add r10, r10, r11 /* add it */
630 mfctr r11 /* restore r11 */
632 154: mfspr r11, SPRN_SPRG_SCRATCH0 /* load r10 from SPRN_SPRG_SCRATCH0 */
633 add r10, r10, r11 /* add it */
634 mfctr r11 /* restore r11 */
639 * This is where the main kernel code starts.
644 ori r2,r2,init_task@l
646 /* ptr to phys current thread */
648 addi r4,r4,THREAD /* init task's THREAD */
649 mtspr SPRN_SPRG_THREAD,r4
652 lis r1,init_thread_union@ha
653 addi r1,r1,init_thread_union@l
655 stwu r0,THREAD_SIZE-STACK_FRAME_OVERHEAD(r1)
657 bl early_init /* We have to do this with MMU on */
660 * Decide what sort of machine this is and initialize the MMU.
668 * Go back to running unmapped so we can load up new values
669 * and change to using our exception vectors.
670 * On the 8xx, all we have to do is invalidate the TLB to clear
671 * the old 8M byte TLB mappings and load the page table base register.
673 /* The right way to do this would be to track it down through
674 * init's THREAD like the context switch code does, but this is
675 * easier......until someone changes init's static structures.
677 lis r6, swapper_pg_dir@ha
679 #ifdef CONFIG_8xx_CPU6
680 lis r4, cpu6_errata_word@h
681 ori r4, r4, cpu6_errata_word@l
690 li r3,MSR_KERNEL & ~(MSR_IR|MSR_DR)
694 /* Load up the kernel context */
696 SYNC /* Force all PTE updates to finish */
697 tlbia /* Clear all TLB entries */
698 sync /* wait for tlbia/tlbie to finish */
699 TLBSYNC /* ... on all CPUs */
701 /* set up the PTE pointers for the Abatron bdiGDB.
704 lis r5, abatron_pteptrs@h
705 ori r5, r5, abatron_pteptrs@l
706 stw r5, 0xf0(r0) /* Must match your Abatron config file */
710 /* Now turn on the MMU for real! */
712 lis r3,start_kernel@h
713 ori r3,r3,start_kernel@l
716 rfi /* enable MMU and jump to start_kernel */
718 /* Set up the initial MMU state so we can do the first level of
719 * kernel initialization. This maps the first 8 MBytes of memory 1:1
720 * virtual to physical. Also, set the cache mode since that is defined
721 * by TLB entries and perform any additional mapping (like of the IMMR).
722 * If configured to pin some TLBs, we pin the first 8 Mbytes of kernel,
723 * 24 Mbytes of data, and the 8M IMMR space. Anything not covered by
724 * these mappings is mapped by page tables.
727 tlbia /* Invalidate all TLB entries */
728 /* Always pin the first 8 MB ITLB to prevent ITLB
729 misses while mucking around with SRR0/SRR1 in asm
734 mtspr SPRN_MI_CTR, r8 /* Set instruction MMU control */
736 #ifdef CONFIG_PIN_TLB
737 lis r10, (MD_RSV4I | MD_RESETVAL)@h
741 lis r10, MD_RESETVAL@h
743 #ifndef CONFIG_8xx_COPYBACK
744 oris r10, r10, MD_WTDEF@h
746 mtspr SPRN_MD_CTR, r10 /* Set data TLB control */
748 /* Now map the lower 8 Meg into the TLBs. For this quick hack,
749 * we can load the instruction and data TLB registers with the
752 lis r8, KERNELBASE@h /* Create vaddr for TLB */
753 ori r8, r8, MI_EVALID /* Mark it valid */
754 mtspr SPRN_MI_EPN, r8
755 mtspr SPRN_MD_EPN, r8
756 li r8, MI_PS8MEG /* Set 8M byte page */
757 ori r8, r8, MI_SVALID /* Make it valid */
758 mtspr SPRN_MI_TWC, r8
759 mtspr SPRN_MD_TWC, r8
760 li r8, MI_BOOTINIT /* Create RPN for address 0 */
761 mtspr SPRN_MI_RPN, r8 /* Store TLB entry */
762 mtspr SPRN_MD_RPN, r8
763 lis r8, MI_Kp@h /* Set the protection mode */
767 /* Map another 8 MByte at the IMMR to get the processor
768 * internal registers (among other things).
770 #ifdef CONFIG_PIN_TLB
771 addi r10, r10, 0x0100
772 mtspr SPRN_MD_CTR, r10
774 mfspr r9, 638 /* Get current IMMR */
775 andis. r9, r9, 0xff80 /* Get 8Mbyte boundary */
777 mr r8, r9 /* Create vaddr for TLB */
778 ori r8, r8, MD_EVALID /* Mark it valid */
779 mtspr SPRN_MD_EPN, r8
780 li r8, MD_PS8MEG /* Set 8M byte page */
781 ori r8, r8, MD_SVALID /* Make it valid */
782 mtspr SPRN_MD_TWC, r8
783 mr r8, r9 /* Create paddr for TLB */
784 ori r8, r8, MI_BOOTINIT|0x2 /* Inhibit cache -- Cort */
785 mtspr SPRN_MD_RPN, r8
787 #ifdef CONFIG_PIN_TLB
788 /* Map two more 8M kernel data pages.
790 addi r10, r10, 0x0100
791 mtspr SPRN_MD_CTR, r10
793 lis r8, KERNELBASE@h /* Create vaddr for TLB */
794 addis r8, r8, 0x0080 /* Add 8M */
795 ori r8, r8, MI_EVALID /* Mark it valid */
796 mtspr SPRN_MD_EPN, r8
797 li r9, MI_PS8MEG /* Set 8M byte page */
798 ori r9, r9, MI_SVALID /* Make it valid */
799 mtspr SPRN_MD_TWC, r9
800 li r11, MI_BOOTINIT /* Create RPN for address 0 */
801 addis r11, r11, 0x0080 /* Add 8M */
802 mtspr SPRN_MD_RPN, r11
804 addi r10, r10, 0x0100
805 mtspr SPRN_MD_CTR, r10
807 addis r8, r8, 0x0080 /* Add 8M */
808 mtspr SPRN_MD_EPN, r8
809 mtspr SPRN_MD_TWC, r9
810 addis r11, r11, 0x0080 /* Add 8M */
811 mtspr SPRN_MD_RPN, r11
814 /* Since the cache is enabled according to the information we
815 * just loaded into the TLB, invalidate and enable the caches here.
816 * We should probably check/set other modes....later.
819 mtspr SPRN_IC_CST, r8
820 mtspr SPRN_DC_CST, r8
822 mtspr SPRN_IC_CST, r8
823 #ifdef CONFIG_8xx_COPYBACK
824 mtspr SPRN_DC_CST, r8
826 /* For a debug option, I left this here to easily enable
827 * the write through cache mode
830 mtspr SPRN_DC_CST, r8
832 mtspr SPRN_DC_CST, r8
838 * Set up to use a given MMU context.
839 * r3 is context number, r4 is PGD pointer.
841 * We place the physical address of the new task page directory loaded
842 * into the MMU base register, and set the ASID compare register with
847 #ifdef CONFIG_BDI_SWITCH
848 /* Context switch the PTE pointer for the Abatron BDI2000.
849 * The PGDIR is passed as second argument.
856 /* Register M_TW will contain base address of level 1 table minus the
857 * lower part of the kernel PGDIR base address, so that all accesses to
858 * level 1 table are done relative to lower part of kernel PGDIR base
861 li r5, (swapper_pg_dir-PAGE_OFFSET)@l
864 #ifdef CONFIG_8xx_CPU6
865 lis r6, cpu6_errata_word@h
866 ori r6, r6, cpu6_errata_word@l
871 mtspr SPRN_M_TW, r4 /* Update pointeur to level 1 table */
872 #ifdef CONFIG_8xx_CPU6
877 mtspr SPRN_M_CASID, r3 /* Update context */
881 #ifdef CONFIG_8xx_CPU6
882 /* It's here because it is unique to the 8xx.
883 * It is important we get called with interrupts disabled. I used to
884 * do that, but it appears that all code that calls this already had
885 * interrupt disabled.
889 lis r7, cpu6_errata_word@h
890 ori r7, r7, cpu6_errata_word@l
894 mtspr 22, r3 /* Update Decrementer */
900 * We put a few things here that have to be page-aligned.
901 * This stuff goes at the beginning of the data segment,
902 * which is page-aligned.
907 .globl empty_zero_page
912 .globl swapper_pg_dir
914 .space PGD_TABLE_SIZE
916 /* Room for two PTE table poiners, usually the kernel and current user
917 * pointer to their respective root page table (pgdir).
922 #ifdef CONFIG_8xx_CPU6
923 .globl cpu6_errata_word