1 /* SPDX-License-Identifier: GPL-2.0-or-later */
3 * Kernel execution entry point code.
5 * Copyright (c) 1995-1996 Gary Thomas <gdt@linuxppc.org>
6 * Initial PowerPC version.
7 * Copyright (c) 1996 Cort Dougan <cort@cs.nmt.edu>
9 * Copyright (c) 1996 Paul Mackerras <paulus@cs.anu.edu.au>
10 * Low-level exception handers, MMU support, and rewrite.
11 * Copyright (c) 1997 Dan Malek <dmalek@jlc.net>
12 * PowerPC 8xx modifications.
13 * Copyright (c) 1998-1999 TiVo, Inc.
14 * PowerPC 403GCX modifications.
15 * Copyright (c) 1999 Grant Erickson <grant@lcse.umn.edu>
16 * PowerPC 403GCX/405GP modifications.
17 * Copyright 2000 MontaVista Software Inc.
18 * PPC405 modifications
19 * PowerPC 403GCX/405GP modifications.
20 * Author: MontaVista Software, Inc.
21 * frank_rowand@mvista.com or source@mvista.com
22 * debbie_chu@mvista.com
23 * Copyright 2002-2005 MontaVista Software, Inc.
24 * PowerPC 44x support, Matt Porter <mporter@kernel.crashing.org>
27 #include <linux/init.h>
28 #include <linux/pgtable.h>
29 #include <asm/processor.h>
32 #include <asm/cputable.h>
33 #include <asm/thread_info.h>
34 #include <asm/ppc_asm.h>
35 #include <asm/asm-offsets.h>
36 #include <asm/ptrace.h>
37 #include <asm/synch.h>
38 #include <asm/export.h>
39 #include <asm/code-patching-asm.h>
40 #include "head_booke.h"
43 /* As with the other PowerPC ports, it is expected that when code
44 * execution begins here, the following registers contain valid, yet
45 * optional, information:
47 * r3 - Board info structure pointer (DRAM, frequency, MAC address, etc.)
48 * r4 - Starting address of the init RAM disk
49 * r5 - Ending address of the init RAM disk
50 * r6 - Start of kernel command line string (e.g. "mem=128")
51 * r7 - End of kernel command line string
58 * Reserve a word at a fixed location to store the address
62 mr r31,r3 /* save device tree ptr */
63 li r24,0 /* CPU number */
65 #ifdef CONFIG_RELOCATABLE
67 * Relocate ourselves to the current runtime address.
68 * This is called only by the Boot CPU.
69 * "relocate" is called with our current runtime virutal
71 * r21 will be loaded with the physical runtime address of _stext
73 bl 0f /* Get our runtime address */
74 0: mflr r21 /* Make it accessible */
75 addis r21,r21,(_stext - 0b)@ha
76 addi r21,r21,(_stext - 0b)@l /* Get our current runtime base */
79 * We have the runtime (virutal) address of our base.
80 * We calculate our shift of offset from a 256M page.
81 * We could map the 256M page we belong to at PAGE_OFFSET and
82 * get going from there.
85 ori r4,r4,KERNELBASE@l
86 rlwinm r6,r21,0,4,31 /* r6 = PHYS_START % 256M */
87 rlwinm r5,r4,0,4,31 /* r5 = KERNELBASE % 256M */
88 subf r3,r5,r6 /* r3 = r6 - r5 */
89 add r3,r4,r3 /* Required Virutal Address */
97 * This is where the main kernel code starts.
102 ori r2,r2,init_task@l
104 /* ptr to current thread */
105 addi r4,r2,THREAD /* init task's THREAD */
106 mtspr SPRN_SPRG_THREAD,r4
109 lis r1,init_thread_union@h
110 ori r1,r1,init_thread_union@l
112 stwu r0,THREAD_SIZE-STACK_FRAME_OVERHEAD(r1)
116 #ifdef CONFIG_RELOCATABLE
118 * Relocatable kernel support based on processing of dynamic
119 * relocation entries.
121 * r25 will contain RPN/ERPN for the start address of memory
122 * r21 will contain the current offset of _stext
124 lis r3,kernstart_addr@ha
125 la r3,kernstart_addr@l(r3)
128 * Compute the kernstart_addr.
129 * kernstart_addr => (r6,r8)
130 * kernstart_addr & ~0xfffffff => (r6,r7)
132 rlwinm r6,r25,0,28,31 /* ERPN. Bits 32-35 of Address */
133 rlwinm r7,r25,0,0,3 /* RPN - assuming 256 MB page size */
134 rlwinm r8,r21,0,4,31 /* r8 = (_stext & 0xfffffff) */
135 or r8,r7,r8 /* Compute the lower 32bit of kernstart_addr */
137 /* Store kernstart_addr */
138 stw r6,0(r3) /* higher 32bit */
139 stw r8,4(r3) /* lower 32bit */
142 * Compute the virt_phys_offset :
143 * virt_phys_offset = stext.run - kernstart_addr
145 * stext.run = (KERNELBASE & ~0xfffffff) + (kernstart_addr & 0xfffffff)
146 * When we relocate, we have :
148 * (kernstart_addr & 0xfffffff) = (stext.run & 0xfffffff)
151 * virt_phys_offset = (KERNELBASE & ~0xfffffff) - (kernstart_addr & ~0xfffffff)
155 /* KERNELBASE&~0xfffffff => (r4,r5) */
156 li r4, 0 /* higer 32bit */
158 rlwinm r5,r5,0,0,3 /* Align to 256M, lower 32bit */
166 /* Store virt_phys_offset */
167 lis r3,virt_phys_offset@ha
168 la r3,virt_phys_offset@l(r3)
173 #elif defined(CONFIG_DYNAMIC_MEMSTART)
175 * Mapping based, page aligned dynamic kernel loading.
177 * r25 will contain RPN/ERPN for the start address of memory
179 * Add the difference between KERNELBASE and PAGE_OFFSET to the
180 * start of physical memory to get kernstart_addr.
182 lis r3,kernstart_addr@ha
183 la r3,kernstart_addr@l(r3)
186 ori r4,r4,KERNELBASE@l
188 ori r5,r5,PAGE_OFFSET@l
191 rlwinm r6,r25,0,28,31 /* ERPN */
192 rlwinm r7,r25,0,0,3 /* RPN - assuming 256 MB page size */
200 * Decide what sort of machine this is and initialize the MMU.
210 /* Setup PTE pointers for the Abatron bdiGDB */
211 lis r6, swapper_pg_dir@h
212 ori r6, r6, swapper_pg_dir@l
213 lis r5, abatron_pteptrs@h
214 ori r5, r5, abatron_pteptrs@l
216 ori r4, r4, KERNELBASE@l
217 stw r5, 0(r4) /* Save abatron_pteptrs at a fixed location */
220 /* Clear the Machine Check Syndrome Register */
225 lis r4,start_kernel@h
226 ori r4,r4,start_kernel@l
228 ori r3,r3,MSR_KERNEL@l
231 rfi /* change context and jump to start_kernel */
234 * Interrupt vector entry code
236 * The Book E MMUs are always on so we don't need to handle
237 * interrupts in real mode as with previous PPC processors. In
238 * this case we handle interrupts in the kernel virtual address
241 * Interrupt vectors are dynamically placed relative to the
242 * interrupt prefix as determined by the address of interrupt_base.
243 * The interrupt vectors offsets are programmed using the labels
244 * for each interrupt vector entry.
246 * Interrupt vectors must be aligned on a 16 byte boundary.
247 * We align on a 32 byte cache line boundary for good measure.
251 /* Critical Input Interrupt */
252 CRITICAL_EXCEPTION(0x0100, CRITICAL, CriticalInput, unknown_exception)
254 /* Machine Check Interrupt */
255 CRITICAL_EXCEPTION(0x0200, MACHINE_CHECK, MachineCheck, \
256 machine_check_exception)
257 MCHECK_EXCEPTION(0x0210, MachineCheckA, machine_check_exception)
259 /* Data Storage Interrupt */
260 DATA_STORAGE_EXCEPTION
262 /* Instruction Storage Interrupt */
263 INSTRUCTION_STORAGE_EXCEPTION
265 /* External Input Interrupt */
266 EXCEPTION(0x0500, BOOKE_INTERRUPT_EXTERNAL, ExternalInput, do_IRQ)
268 /* Alignment Interrupt */
271 /* Program Interrupt */
274 /* Floating Point Unavailable Interrupt */
275 #ifdef CONFIG_PPC_FPU
276 FP_UNAVAILABLE_EXCEPTION
278 EXCEPTION(0x2010, BOOKE_INTERRUPT_FP_UNAVAIL, \
279 FloatingPointUnavailable, unknown_exception)
281 /* System Call Interrupt */
282 START_EXCEPTION(SystemCall)
283 SYSCALL_ENTRY 0xc00 BOOKE_INTERRUPT_SYSCALL
285 /* Auxiliary Processor Unavailable Interrupt */
286 EXCEPTION(0x2020, BOOKE_INTERRUPT_AP_UNAVAIL, \
287 AuxillaryProcessorUnavailable, unknown_exception)
289 /* Decrementer Interrupt */
290 DECREMENTER_EXCEPTION
292 /* Fixed Internal Timer Interrupt */
293 /* TODO: Add FIT support */
294 EXCEPTION(0x1010, BOOKE_INTERRUPT_FIT, FixedIntervalTimer, unknown_exception)
296 /* Watchdog Timer Interrupt */
297 /* TODO: Add watchdog support */
298 #ifdef CONFIG_BOOKE_WDT
299 CRITICAL_EXCEPTION(0x1020, WATCHDOG, WatchdogTimer, WatchdogException)
301 CRITICAL_EXCEPTION(0x1020, WATCHDOG, WatchdogTimer, unknown_exception)
304 /* Data TLB Error Interrupt */
305 START_EXCEPTION(DataTLBError44x)
306 mtspr SPRN_SPRG_WSCRATCH0, r10 /* Save some working registers */
307 mtspr SPRN_SPRG_WSCRATCH1, r11
308 mtspr SPRN_SPRG_WSCRATCH2, r12
309 mtspr SPRN_SPRG_WSCRATCH3, r13
311 mtspr SPRN_SPRG_WSCRATCH4, r11
312 mfspr r10, SPRN_DEAR /* Get faulting address */
314 /* If we are faulting a kernel address, we have to use the
315 * kernel page tables.
317 lis r11, PAGE_OFFSET@h
320 lis r11, swapper_pg_dir@h
321 ori r11, r11, swapper_pg_dir@l
324 rlwinm r12,r12,0,0,23 /* Clear TID */
328 /* Get the PGD for the current thread */
330 mfspr r11,SPRN_SPRG_THREAD
333 /* Load PID into MMUCR TID */
335 mfspr r13,SPRN_PID /* Get PID */
336 rlwimi r12,r13,0,24,31 /* Set TID */
341 /* Mask of required permission bits. Note that while we
342 * do copy ESR:ST to _PAGE_RW position as trying to write
343 * to an RO page is pretty common, we don't do it with
344 * _PAGE_DIRTY. We could do it, but it's a fairly rare
345 * event so I'd rather take the overhead when it happens
346 * rather than adding an instruction here. We should measure
347 * whether the whole thing is worth it in the first place
348 * as we could avoid loading SPRN_ESR completely in the first
351 * TODO: Is it worth doing that mfspr & rlwimi in the first
352 * place or can we save a couple of instructions here ?
355 li r13,_PAGE_PRESENT|_PAGE_ACCESSED
356 rlwimi r13,r12,10,30,30
359 /* Compute pgdir/pmd offset */
360 rlwinm r12, r10, PPC44x_PGD_OFF_SHIFT, PPC44x_PGD_OFF_MASK_BIT, 29
361 lwzx r11, r12, r11 /* Get pgd/pmd entry */
362 rlwinm. r12, r11, 0, 0, 20 /* Extract pt base address */
363 beq 2f /* Bail if no table */
365 /* Compute pte address */
366 rlwimi r12, r10, PPC44x_PTE_ADD_SHIFT, PPC44x_PTE_ADD_MASK_BIT, 28
367 lwz r11, 0(r12) /* Get high word of pte entry */
368 lwz r12, 4(r12) /* Get low word of pte entry */
370 lis r10,tlb_44x_index@ha
372 andc. r13,r13,r12 /* Check permission */
374 /* Load the next available TLB index */
375 lwz r13,tlb_44x_index@l(r10)
377 bne 2f /* Bail if permission mismatch */
379 /* Increment, rollover, and store TLB index */
382 patch_site 0f, patch__tlb_44x_hwater_D
383 /* Compare with watermark (instruction gets patched) */
384 0: cmpwi 0,r13,1 /* reserve entries */
388 /* Store the next available TLB index */
389 stw r13,tlb_44x_index@l(r10)
391 /* Re-load the faulting address */
394 /* Jump to common tlb load */
395 b finish_tlb_load_44x
398 /* The bailout. Restore registers to pre-exception conditions
399 * and call the heavyweights to help us out.
401 mfspr r11, SPRN_SPRG_RSCRATCH4
403 mfspr r13, SPRN_SPRG_RSCRATCH3
404 mfspr r12, SPRN_SPRG_RSCRATCH2
405 mfspr r11, SPRN_SPRG_RSCRATCH1
406 mfspr r10, SPRN_SPRG_RSCRATCH0
409 /* Instruction TLB Error Interrupt */
411 * Nearly the same as above, except we get our
412 * information from different registers and bailout
413 * to a different point.
415 START_EXCEPTION(InstructionTLBError44x)
416 mtspr SPRN_SPRG_WSCRATCH0, r10 /* Save some working registers */
417 mtspr SPRN_SPRG_WSCRATCH1, r11
418 mtspr SPRN_SPRG_WSCRATCH2, r12
419 mtspr SPRN_SPRG_WSCRATCH3, r13
421 mtspr SPRN_SPRG_WSCRATCH4, r11
422 mfspr r10, SPRN_SRR0 /* Get faulting address */
424 /* If we are faulting a kernel address, we have to use the
425 * kernel page tables.
427 lis r11, PAGE_OFFSET@h
430 lis r11, swapper_pg_dir@h
431 ori r11, r11, swapper_pg_dir@l
434 rlwinm r12,r12,0,0,23 /* Clear TID */
438 /* Get the PGD for the current thread */
440 mfspr r11,SPRN_SPRG_THREAD
443 /* Load PID into MMUCR TID */
445 mfspr r13,SPRN_PID /* Get PID */
446 rlwimi r12,r13,0,24,31 /* Set TID */
451 /* Make up the required permissions */
452 li r13,_PAGE_PRESENT | _PAGE_ACCESSED | _PAGE_EXEC
454 /* Compute pgdir/pmd offset */
455 rlwinm r12, r10, PPC44x_PGD_OFF_SHIFT, PPC44x_PGD_OFF_MASK_BIT, 29
456 lwzx r11, r12, r11 /* Get pgd/pmd entry */
457 rlwinm. r12, r11, 0, 0, 20 /* Extract pt base address */
458 beq 2f /* Bail if no table */
460 /* Compute pte address */
461 rlwimi r12, r10, PPC44x_PTE_ADD_SHIFT, PPC44x_PTE_ADD_MASK_BIT, 28
462 lwz r11, 0(r12) /* Get high word of pte entry */
463 lwz r12, 4(r12) /* Get low word of pte entry */
465 lis r10,tlb_44x_index@ha
467 andc. r13,r13,r12 /* Check permission */
469 /* Load the next available TLB index */
470 lwz r13,tlb_44x_index@l(r10)
472 bne 2f /* Bail if permission mismatch */
474 /* Increment, rollover, and store TLB index */
477 patch_site 0f, patch__tlb_44x_hwater_I
478 /* Compare with watermark (instruction gets patched) */
479 0: cmpwi 0,r13,1 /* reserve entries */
483 /* Store the next available TLB index */
484 stw r13,tlb_44x_index@l(r10)
486 /* Re-load the faulting address */
489 /* Jump to common TLB load point */
490 b finish_tlb_load_44x
493 /* The bailout. Restore registers to pre-exception conditions
494 * and call the heavyweights to help us out.
496 mfspr r11, SPRN_SPRG_RSCRATCH4
498 mfspr r13, SPRN_SPRG_RSCRATCH3
499 mfspr r12, SPRN_SPRG_RSCRATCH2
500 mfspr r11, SPRN_SPRG_RSCRATCH1
501 mfspr r10, SPRN_SPRG_RSCRATCH0
505 * Both the instruction and data TLB miss get to this
506 * point to load the TLB.
508 * r11 - PTE high word value
509 * r12 - PTE low word value
511 * MMUCR - loaded with proper value when we get here
512 * Upon exit, we reload everything and RFI.
515 /* Combine RPN & ERPN an write WS 0 */
516 rlwimi r11,r12,0,0,31-PAGE_SHIFT
517 tlbwe r11,r13,PPC44x_TLB_XLAT
520 * Create WS1. This is the faulting address (EPN),
521 * page size, and valid flag.
523 li r11,PPC44x_TLB_VALID | PPC44x_TLBE_SIZE
524 /* Insert valid and page size */
525 rlwimi r10,r11,0,PPC44x_PTE_ADD_MASK_BIT,31
526 tlbwe r10,r13,PPC44x_TLB_PAGEID /* Write PAGEID */
529 li r10,0xf85 /* Mask to apply from PTE */
530 rlwimi r10,r12,29,30,30 /* DIRTY -> SW position */
531 and r11,r12,r10 /* Mask PTE bits to keep */
532 andi. r10,r12,_PAGE_USER /* User page ? */
533 beq 1f /* nope, leave U bits empty */
534 rlwimi r11,r11,3,26,28 /* yes, copy S bits to U */
535 1: tlbwe r11,r13,PPC44x_TLB_ATTRIB /* Write ATTRIB */
537 /* Done...restore registers and get out of here.
539 mfspr r11, SPRN_SPRG_RSCRATCH4
541 mfspr r13, SPRN_SPRG_RSCRATCH3
542 mfspr r12, SPRN_SPRG_RSCRATCH2
543 mfspr r11, SPRN_SPRG_RSCRATCH1
544 mfspr r10, SPRN_SPRG_RSCRATCH0
545 rfi /* Force context change */
547 /* TLB error interrupts for 476
549 #ifdef CONFIG_PPC_47x
550 START_EXCEPTION(DataTLBError47x)
551 mtspr SPRN_SPRG_WSCRATCH0,r10 /* Save some working registers */
552 mtspr SPRN_SPRG_WSCRATCH1,r11
553 mtspr SPRN_SPRG_WSCRATCH2,r12
554 mtspr SPRN_SPRG_WSCRATCH3,r13
556 mtspr SPRN_SPRG_WSCRATCH4,r11
557 mfspr r10,SPRN_DEAR /* Get faulting address */
559 /* If we are faulting a kernel address, we have to use the
560 * kernel page tables.
562 lis r11,PAGE_OFFSET@h
565 lis r11,swapper_pg_dir@h
566 ori r11,r11, swapper_pg_dir@l
567 li r12,0 /* MMUCR = 0 */
570 /* Get the PGD for the current thread and setup MMUCR */
571 3: mfspr r11,SPRN_SPRG3
573 mfspr r12,SPRN_PID /* Get PID */
574 4: mtspr SPRN_MMUCR,r12 /* Set MMUCR */
576 /* Mask of required permission bits. Note that while we
577 * do copy ESR:ST to _PAGE_RW position as trying to write
578 * to an RO page is pretty common, we don't do it with
579 * _PAGE_DIRTY. We could do it, but it's a fairly rare
580 * event so I'd rather take the overhead when it happens
581 * rather than adding an instruction here. We should measure
582 * whether the whole thing is worth it in the first place
583 * as we could avoid loading SPRN_ESR completely in the first
586 * TODO: Is it worth doing that mfspr & rlwimi in the first
587 * place or can we save a couple of instructions here ?
590 li r13,_PAGE_PRESENT|_PAGE_ACCESSED
591 rlwimi r13,r12,10,30,30
594 /* Compute pgdir/pmd offset */
595 rlwinm r12,r10,PPC44x_PGD_OFF_SHIFT,PPC44x_PGD_OFF_MASK_BIT,29
596 lwzx r11,r12,r11 /* Get pgd/pmd entry */
598 /* Word 0 is EPN,V,TS,DSIZ */
599 li r12,PPC47x_TLB0_VALID | PPC47x_TLBE_SIZE
600 rlwimi r10,r12,0,32-PAGE_SHIFT,31 /* Insert valid and page size*/
604 /* XXX can we do better ? Need to make sure tlbwe has established
605 * latch V bit in MMUCR0 before the PTE is loaded further down */
610 rlwinm. r12,r11,0,0,20 /* Extract pt base address */
611 /* Compute pte address */
612 rlwimi r12,r10,PPC44x_PTE_ADD_SHIFT,PPC44x_PTE_ADD_MASK_BIT,28
613 beq 2f /* Bail if no table */
614 lwz r11,0(r12) /* Get high word of pte entry */
616 /* XXX can we do better ? maybe insert a known 0 bit from r11 into the
617 * bottom of r12 to create a data dependency... We can also use r10
618 * as destination nowadays
623 lwz r12,4(r12) /* Get low word of pte entry */
625 andc. r13,r13,r12 /* Check permission */
627 /* Jump to common tlb load */
628 beq finish_tlb_load_47x
630 2: /* The bailout. Restore registers to pre-exception conditions
631 * and call the heavyweights to help us out.
633 mfspr r11,SPRN_SPRG_RSCRATCH4
635 mfspr r13,SPRN_SPRG_RSCRATCH3
636 mfspr r12,SPRN_SPRG_RSCRATCH2
637 mfspr r11,SPRN_SPRG_RSCRATCH1
638 mfspr r10,SPRN_SPRG_RSCRATCH0
641 /* Instruction TLB Error Interrupt */
643 * Nearly the same as above, except we get our
644 * information from different registers and bailout
645 * to a different point.
647 START_EXCEPTION(InstructionTLBError47x)
648 mtspr SPRN_SPRG_WSCRATCH0,r10 /* Save some working registers */
649 mtspr SPRN_SPRG_WSCRATCH1,r11
650 mtspr SPRN_SPRG_WSCRATCH2,r12
651 mtspr SPRN_SPRG_WSCRATCH3,r13
653 mtspr SPRN_SPRG_WSCRATCH4,r11
654 mfspr r10,SPRN_SRR0 /* Get faulting address */
656 /* If we are faulting a kernel address, we have to use the
657 * kernel page tables.
659 lis r11,PAGE_OFFSET@h
662 lis r11,swapper_pg_dir@h
663 ori r11,r11, swapper_pg_dir@l
664 li r12,0 /* MMUCR = 0 */
667 /* Get the PGD for the current thread and setup MMUCR */
668 3: mfspr r11,SPRN_SPRG_THREAD
670 mfspr r12,SPRN_PID /* Get PID */
671 4: mtspr SPRN_MMUCR,r12 /* Set MMUCR */
673 /* Make up the required permissions */
674 li r13,_PAGE_PRESENT | _PAGE_ACCESSED | _PAGE_EXEC
677 /* Compute pgdir/pmd offset */
678 rlwinm r12,r10,PPC44x_PGD_OFF_SHIFT,PPC44x_PGD_OFF_MASK_BIT,29
679 lwzx r11,r12,r11 /* Get pgd/pmd entry */
681 /* Word 0 is EPN,V,TS,DSIZ */
682 li r12,PPC47x_TLB0_VALID | PPC47x_TLBE_SIZE
683 rlwimi r10,r12,0,32-PAGE_SHIFT,31 /* Insert valid and page size*/
687 /* XXX can we do better ? Need to make sure tlbwe has established
688 * latch V bit in MMUCR0 before the PTE is loaded further down */
693 rlwinm. r12,r11,0,0,20 /* Extract pt base address */
694 /* Compute pte address */
695 rlwimi r12,r10,PPC44x_PTE_ADD_SHIFT,PPC44x_PTE_ADD_MASK_BIT,28
696 beq 2f /* Bail if no table */
698 lwz r11,0(r12) /* Get high word of pte entry */
699 /* XXX can we do better ? maybe insert a known 0 bit from r11 into the
700 * bottom of r12 to create a data dependency... We can also use r10
701 * as destination nowadays
706 lwz r12,4(r12) /* Get low word of pte entry */
708 andc. r13,r13,r12 /* Check permission */
710 /* Jump to common TLB load point */
711 beq finish_tlb_load_47x
713 2: /* The bailout. Restore registers to pre-exception conditions
714 * and call the heavyweights to help us out.
716 mfspr r11, SPRN_SPRG_RSCRATCH4
718 mfspr r13, SPRN_SPRG_RSCRATCH3
719 mfspr r12, SPRN_SPRG_RSCRATCH2
720 mfspr r11, SPRN_SPRG_RSCRATCH1
721 mfspr r10, SPRN_SPRG_RSCRATCH0
725 * Both the instruction and data TLB miss get to this
726 * point to load the TLB.
728 * r11 - PTE high word value
729 * r12 - PTE low word value
731 * MMUCR - loaded with proper value when we get here
732 * Upon exit, we reload everything and RFI.
735 /* Combine RPN & ERPN an write WS 1 */
736 rlwimi r11,r12,0,0,31-PAGE_SHIFT
739 /* And make up word 2 */
740 li r10,0xf85 /* Mask to apply from PTE */
741 rlwimi r10,r12,29,30,30 /* DIRTY -> SW position */
742 and r11,r12,r10 /* Mask PTE bits to keep */
743 andi. r10,r12,_PAGE_USER /* User page ? */
744 beq 1f /* nope, leave U bits empty */
745 rlwimi r11,r11,3,26,28 /* yes, copy S bits to U */
748 /* Done...restore registers and get out of here.
750 mfspr r11, SPRN_SPRG_RSCRATCH4
752 mfspr r13, SPRN_SPRG_RSCRATCH3
753 mfspr r12, SPRN_SPRG_RSCRATCH2
754 mfspr r11, SPRN_SPRG_RSCRATCH1
755 mfspr r10, SPRN_SPRG_RSCRATCH0
758 #endif /* CONFIG_PPC_47x */
760 /* Debug Interrupt */
762 * This statement needs to exist at the end of the IVPR
763 * definition just in case you end up taking a debug
764 * exception within another exception.
775 * Adjust the machine check IVOR on 440A cores
777 _GLOBAL(__fixup_440A_mcheck)
778 li r3,MachineCheckA@l
785 #ifdef CONFIG_BDI_SWITCH
786 /* Context switch the PTE pointer for the Abatron BDI2000.
787 * The PGDIR is the second parameter.
789 lis r5, abatron_pteptrs@h
790 ori r5, r5, abatron_pteptrs@l
794 isync /* Force context change */
798 * Init CPU state. This is called at boot time or for secondary CPUs
799 * to setup initial TLB entries, setup IVORs, etc...
802 _GLOBAL(init_cpu_state)
804 #ifdef CONFIG_PPC_47x
805 /* We use the PVR to differentiate 44x cores from 476 */
808 cmplwi cr0,r3,PVR_476FPE@h
810 cmplwi cr0,r3,PVR_476@h
812 cmplwi cr0,r3,PVR_476_ISS@h
814 #endif /* CONFIG_PPC_47x */
817 * In case the firmware didn't do it, we apply some workarounds
818 * that are good for all 440 core variants here
821 rlwinm r3,r3,0,0,27 /* disable icache prefetch */
828 * Set up the initial MMU state for 44x
830 * We are still executing code at the virtual address
831 * mappings set by the firmware for the base of RAM.
833 * We first invalidate all TLB entries but the one
834 * we are running from. We then load the KERNELBASE
835 * mappings so we can begin to use kernel addresses
836 * natively and so the interrupt vector locations are
837 * permanently pinned (necessary since Book E
838 * implementations always have translation enabled).
840 * TODO: Use the known TLB entry we are running from to
841 * determine which physical region we are located
842 * in. This can be used to determine where in RAM
843 * (on a shared CPU system) or PCI memory space
844 * (on a DRAMless system) we are located.
845 * For now, we assume a perfect world which means
846 * we are located at the base of DRAM (physical 0).
850 * Search TLB for entry that we are currently using.
851 * Invalidate all entries but the one we are using.
853 /* Load our current PID->MMUCR TID and MSR IS->MMUCR STS */
854 mfspr r3,SPRN_PID /* Get PID */
855 mfmsr r4 /* Get MSR */
856 andi. r4,r4,MSR_IS@l /* TS=1? */
857 beq wmmucr /* If not, leave STS=0 */
858 oris r3,r3,PPC44x_MMUCR_STS@h /* Set STS=1 */
859 wmmucr: mtspr SPRN_MMUCR,r3 /* Put MMUCR */
862 bl invstr /* Find our address */
863 invstr: mflr r5 /* Make it accessible */
864 tlbsx r23,0,r5 /* Find entry we are in */
865 li r4,0 /* Start at TLB entry 0 */
866 li r3,0 /* Set PAGEID inval value */
867 1: cmpw r23,r4 /* Is this our entry? */
868 beq skpinv /* If so, skip the inval */
869 tlbwe r3,r4,PPC44x_TLB_PAGEID /* If not, inval the entry */
870 skpinv: addi r4,r4,1 /* Increment */
871 cmpwi r4,64 /* Are we done? */
872 bne 1b /* If not, repeat */
873 isync /* If so, context change */
876 * Configure and load pinned entry into TLB slot 63.
878 #ifdef CONFIG_NONSTATIC_KERNEL
880 * In case of a NONSTATIC_KERNEL we reuse the TLB XLAT
881 * entries of the initial mapping set by the boot loader.
882 * The XLAT entry is stored in r25
885 /* Read the XLAT entry for our current mapping */
886 tlbre r25,r23,PPC44x_TLB_XLAT
889 ori r3,r3,KERNELBASE@l
891 /* Use our current RPN entry */
896 ori r3,r3,PAGE_OFFSET@l
898 /* Kernel is at the base of RAM */
899 li r4, 0 /* Load the kernel physical address */
902 /* Load the kernel PID = 0 */
907 /* Initialize MMUCR */
913 clrrwi r3,r3,10 /* Mask off the effective page number */
914 ori r3,r3,PPC44x_TLB_VALID | PPC44x_TLB_256M
917 clrrwi r4,r4,10 /* Mask off the real page number */
918 /* ERPN is 0 for first 4GB page */
921 /* Added guarded bit to protect against speculative loads/stores */
923 ori r5,r5,(PPC44x_TLB_SW | PPC44x_TLB_SR | PPC44x_TLB_SX | PPC44x_TLB_G)
925 li r0,63 /* TLB slot 63 */
927 tlbwe r3,r0,PPC44x_TLB_PAGEID /* Load the pageid fields */
928 tlbwe r4,r0,PPC44x_TLB_XLAT /* Load the translation fields */
929 tlbwe r5,r0,PPC44x_TLB_ATTRIB /* Load the attrib/access fields */
931 /* Force context change */
940 /* If necessary, invalidate original entry we used */
944 tlbwe r6,r23,PPC44x_TLB_PAGEID
948 #ifdef CONFIG_PPC_EARLY_DEBUG_44x
949 /* Add UART mapping for early debug. */
952 lis r3,PPC44x_EARLY_DEBUG_VIRTADDR@h
953 ori r3,r3,PPC44x_TLB_VALID|PPC44x_TLB_TS|PPC44x_TLB_64K
956 lis r4,CONFIG_PPC_EARLY_DEBUG_44x_PHYSLOW@h
957 ori r4,r4,CONFIG_PPC_EARLY_DEBUG_44x_PHYSHIGH
960 li r5,(PPC44x_TLB_SW|PPC44x_TLB_SR|PPC44x_TLB_I|PPC44x_TLB_G)
961 li r0,62 /* TLB slot 0 */
963 tlbwe r3,r0,PPC44x_TLB_PAGEID
964 tlbwe r4,r0,PPC44x_TLB_XLAT
965 tlbwe r5,r0,PPC44x_TLB_ATTRIB
967 /* Force context change */
969 #endif /* CONFIG_PPC_EARLY_DEBUG_44x */
971 /* Establish the interrupt vector offsets */
972 SET_IVOR(0, CriticalInput);
973 SET_IVOR(1, MachineCheck);
974 SET_IVOR(2, DataStorage);
975 SET_IVOR(3, InstructionStorage);
976 SET_IVOR(4, ExternalInput);
977 SET_IVOR(5, Alignment);
978 SET_IVOR(6, Program);
979 SET_IVOR(7, FloatingPointUnavailable);
980 SET_IVOR(8, SystemCall);
981 SET_IVOR(9, AuxillaryProcessorUnavailable);
982 SET_IVOR(10, Decrementer);
983 SET_IVOR(11, FixedIntervalTimer);
984 SET_IVOR(12, WatchdogTimer);
985 SET_IVOR(13, DataTLBError44x);
986 SET_IVOR(14, InstructionTLBError44x);
987 SET_IVOR(15, DebugCrit);
992 #ifdef CONFIG_PPC_47x
996 /* Entry point for secondary 47x processors */
997 _GLOBAL(start_secondary_47x)
998 mr r24,r3 /* CPU number */
1002 /* Now we need to bolt the rest of kernel memory which
1003 * is done in C code. We must be careful because our task
1004 * struct or our stack can (and will probably) be out
1005 * of reach of the initial 256M TLB entry, so we use a
1006 * small temporary stack in .bss for that. This works
1007 * because only one CPU at a time can be in this code
1009 lis r1,temp_boot_stack@h
1010 ori r1,r1,temp_boot_stack@l
1011 addi r1,r1,1024-STACK_FRAME_OVERHEAD
1014 bl mmu_init_secondary
1016 /* Now we can get our task struct and real stack pointer */
1018 /* Get current's stack and current */
1019 lis r2,secondary_current@ha
1020 lwz r2,secondary_current@l(r2)
1021 lwz r1,TASK_STACK(r2)
1023 /* Current stack pointer */
1024 addi r1,r1,THREAD_SIZE-STACK_FRAME_OVERHEAD
1028 /* Kernel stack for exception entry in SPRG3 */
1029 addi r4,r2,THREAD /* init task's THREAD */
1034 #endif /* CONFIG_SMP */
1037 * Set up the initial MMU state for 44x
1039 * We are still executing code at the virtual address
1040 * mappings set by the firmware for the base of RAM.
1044 /* Load our current PID->MMUCR TID and MSR IS->MMUCR STS */
1045 mfspr r3,SPRN_PID /* Get PID */
1046 mfmsr r4 /* Get MSR */
1047 andi. r4,r4,MSR_IS@l /* TS=1? */
1048 beq 1f /* If not, leave STS=0 */
1049 oris r3,r3,PPC47x_MMUCR_STS@h /* Set STS=1 */
1050 1: mtspr SPRN_MMUCR,r3 /* Put MMUCR */
1053 /* Find the entry we are running from */
1065 /* Initialize MMUCR */
1070 clear_all_utlb_entries:
1072 #; Set initial values.
1079 #; Align the loop to speed things up.
1090 bne clear_utlb_entry
1094 bne clear_utlb_entry
1096 #; Restore original entry.
1098 oris r23,r23,0x8000 /* specify the way */
1104 * Configure and load pinned entry into TLB for the kernel core
1107 lis r3,PAGE_OFFSET@h
1108 ori r3,r3,PAGE_OFFSET@l
1110 /* Load the kernel PID = 0 */
1116 clrrwi r3,r3,12 /* Mask off the effective page number */
1117 ori r3,r3,PPC47x_TLB0_VALID | PPC47x_TLB0_256M
1119 /* Word 1 - use r25. RPN is the same as the original entry */
1123 ori r5,r5,PPC47x_TLB2_S_RWX
1125 ori r5,r5,PPC47x_TLB2_M
1128 /* We write to way 0 and bolted 0 */
1135 * Configure SSPCR, ISPCR and USPCR for now to search everything, we can fix
1138 LOAD_REG_IMMEDIATE(r3, 0x9abcdef0)
1141 LOAD_REG_IMMEDIATE(r3, 0x12345670)
1144 /* Force context change */
1153 /* Invalidate original entry we used */
1155 rlwinm r24,r24,0,21,19 /* clear the "valid" bit */
1160 isync /* Clear out the shadow TLB entries */
1162 #ifdef CONFIG_PPC_EARLY_DEBUG_44x
1163 /* Add UART mapping for early debug. */
1166 lis r3,PPC44x_EARLY_DEBUG_VIRTADDR@h
1167 ori r3,r3,PPC47x_TLB0_VALID | PPC47x_TLB0_TS | PPC47x_TLB0_1M
1170 lis r4,CONFIG_PPC_EARLY_DEBUG_44x_PHYSLOW@h
1171 ori r4,r4,CONFIG_PPC_EARLY_DEBUG_44x_PHYSHIGH
1174 li r5,(PPC47x_TLB2_S_RW | PPC47x_TLB2_IMG)
1176 /* Bolted in way 0, bolt slot 5, we -hope- we don't hit the same
1177 * congruence class as the kernel, we need to make sure of it at
1185 /* Force context change */
1187 #endif /* CONFIG_PPC_EARLY_DEBUG_44x */
1189 /* Establish the interrupt vector offsets */
1190 SET_IVOR(0, CriticalInput);
1191 SET_IVOR(1, MachineCheckA);
1192 SET_IVOR(2, DataStorage);
1193 SET_IVOR(3, InstructionStorage);
1194 SET_IVOR(4, ExternalInput);
1195 SET_IVOR(5, Alignment);
1196 SET_IVOR(6, Program);
1197 SET_IVOR(7, FloatingPointUnavailable);
1198 SET_IVOR(8, SystemCall);
1199 SET_IVOR(9, AuxillaryProcessorUnavailable);
1200 SET_IVOR(10, Decrementer);
1201 SET_IVOR(11, FixedIntervalTimer);
1202 SET_IVOR(12, WatchdogTimer);
1203 SET_IVOR(13, DataTLBError47x);
1204 SET_IVOR(14, InstructionTLBError47x);
1205 SET_IVOR(15, DebugCrit);
1207 /* We configure icbi to invalidate 128 bytes at a time since the
1208 * current 32-bit kernel code isn't too happy with icache != dcache
1209 * block size. We also disable the BTAC as this can cause errors
1210 * in some circumstances (see IBM Erratum 47).
1218 #endif /* CONFIG_PPC_47x */
1221 * Here we are back to code that is common between 44x and 47x
1223 * We proceed to further kernel initialization and return to the
1227 /* Establish the interrupt vector base */
1228 lis r4,interrupt_base@h /* IVPR only uses the high 16-bits */
1232 * If the kernel was loaded at a non-zero 256 MB page, we need to
1233 * mask off the most significant 4 bits to get the relative address
1234 * from the start of physical memory
1236 rlwinm r22,r22,0,4,31
1237 addis r22,r22,PAGE_OFFSET@h
1243 * We put a few things here that have to be page-aligned. This stuff
1244 * goes at the beginning of the data segment, which is page-aligned.
1250 .globl empty_zero_page
1253 EXPORT_SYMBOL(empty_zero_page)
1256 * To support >32-bit physical addresses, we use an 8KB pgdir.
1258 .globl swapper_pg_dir
1260 .space PGD_TABLE_SIZE
1263 * Room for two PTE pointers, usually the kernel and current user pointers
1264 * to their respective root page table.
1273 #endif /* CONFIG_SMP */