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 bcl 20,31,$+4 /* 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_MIN_SIZE(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 */
337 #ifdef CONFIG_PPC_KUAP
339 beq 2f /* KUAP Fault */
345 /* Mask of required permission bits. Note that while we
346 * do copy ESR:ST to _PAGE_RW position as trying to write
347 * to an RO page is pretty common, we don't do it with
348 * _PAGE_DIRTY. We could do it, but it's a fairly rare
349 * event so I'd rather take the overhead when it happens
350 * rather than adding an instruction here. We should measure
351 * whether the whole thing is worth it in the first place
352 * as we could avoid loading SPRN_ESR completely in the first
355 * TODO: Is it worth doing that mfspr & rlwimi in the first
356 * place or can we save a couple of instructions here ?
359 li r13,_PAGE_PRESENT|_PAGE_ACCESSED
360 rlwimi r13,r12,10,30,30
363 /* Compute pgdir/pmd offset */
364 rlwinm r12, r10, PPC44x_PGD_OFF_SHIFT, PPC44x_PGD_OFF_MASK_BIT, 29
365 lwzx r11, r12, r11 /* Get pgd/pmd entry */
366 rlwinm. r12, r11, 0, 0, 20 /* Extract pt base address */
367 beq 2f /* Bail if no table */
369 /* Compute pte address */
370 rlwimi r12, r10, PPC44x_PTE_ADD_SHIFT, PPC44x_PTE_ADD_MASK_BIT, 28
371 lwz r11, 0(r12) /* Get high word of pte entry */
372 lwz r12, 4(r12) /* Get low word of pte entry */
374 lis r10,tlb_44x_index@ha
376 andc. r13,r13,r12 /* Check permission */
378 /* Load the next available TLB index */
379 lwz r13,tlb_44x_index@l(r10)
381 bne 2f /* Bail if permission mismatch */
383 /* Increment, rollover, and store TLB index */
386 patch_site 0f, patch__tlb_44x_hwater_D
387 /* Compare with watermark (instruction gets patched) */
388 0: cmpwi 0,r13,1 /* reserve entries */
392 /* Store the next available TLB index */
393 stw r13,tlb_44x_index@l(r10)
395 /* Re-load the faulting address */
398 /* Jump to common tlb load */
399 b finish_tlb_load_44x
402 /* The bailout. Restore registers to pre-exception conditions
403 * and call the heavyweights to help us out.
405 mfspr r11, SPRN_SPRG_RSCRATCH4
407 mfspr r13, SPRN_SPRG_RSCRATCH3
408 mfspr r12, SPRN_SPRG_RSCRATCH2
409 mfspr r11, SPRN_SPRG_RSCRATCH1
410 mfspr r10, SPRN_SPRG_RSCRATCH0
413 /* Instruction TLB Error Interrupt */
415 * Nearly the same as above, except we get our
416 * information from different registers and bailout
417 * to a different point.
419 START_EXCEPTION(InstructionTLBError44x)
420 mtspr SPRN_SPRG_WSCRATCH0, r10 /* Save some working registers */
421 mtspr SPRN_SPRG_WSCRATCH1, r11
422 mtspr SPRN_SPRG_WSCRATCH2, r12
423 mtspr SPRN_SPRG_WSCRATCH3, r13
425 mtspr SPRN_SPRG_WSCRATCH4, r11
426 mfspr r10, SPRN_SRR0 /* Get faulting address */
428 /* If we are faulting a kernel address, we have to use the
429 * kernel page tables.
431 lis r11, PAGE_OFFSET@h
434 lis r11, swapper_pg_dir@h
435 ori r11, r11, swapper_pg_dir@l
438 rlwinm r12,r12,0,0,23 /* Clear TID */
442 /* Get the PGD for the current thread */
444 mfspr r11,SPRN_SPRG_THREAD
447 /* Load PID into MMUCR TID */
449 mfspr r13,SPRN_PID /* Get PID */
450 rlwimi r12,r13,0,24,31 /* Set TID */
451 #ifdef CONFIG_PPC_KUAP
453 beq 2f /* KUAP Fault */
459 /* Make up the required permissions */
460 li r13,_PAGE_PRESENT | _PAGE_ACCESSED | _PAGE_EXEC
462 /* Compute pgdir/pmd offset */
463 rlwinm r12, r10, PPC44x_PGD_OFF_SHIFT, PPC44x_PGD_OFF_MASK_BIT, 29
464 lwzx r11, r12, r11 /* Get pgd/pmd entry */
465 rlwinm. r12, r11, 0, 0, 20 /* Extract pt base address */
466 beq 2f /* Bail if no table */
468 /* Compute pte address */
469 rlwimi r12, r10, PPC44x_PTE_ADD_SHIFT, PPC44x_PTE_ADD_MASK_BIT, 28
470 lwz r11, 0(r12) /* Get high word of pte entry */
471 lwz r12, 4(r12) /* Get low word of pte entry */
473 lis r10,tlb_44x_index@ha
475 andc. r13,r13,r12 /* Check permission */
477 /* Load the next available TLB index */
478 lwz r13,tlb_44x_index@l(r10)
480 bne 2f /* Bail if permission mismatch */
482 /* Increment, rollover, and store TLB index */
485 patch_site 0f, patch__tlb_44x_hwater_I
486 /* Compare with watermark (instruction gets patched) */
487 0: cmpwi 0,r13,1 /* reserve entries */
491 /* Store the next available TLB index */
492 stw r13,tlb_44x_index@l(r10)
494 /* Re-load the faulting address */
497 /* Jump to common TLB load point */
498 b finish_tlb_load_44x
501 /* The bailout. Restore registers to pre-exception conditions
502 * and call the heavyweights to help us out.
504 mfspr r11, SPRN_SPRG_RSCRATCH4
506 mfspr r13, SPRN_SPRG_RSCRATCH3
507 mfspr r12, SPRN_SPRG_RSCRATCH2
508 mfspr r11, SPRN_SPRG_RSCRATCH1
509 mfspr r10, SPRN_SPRG_RSCRATCH0
513 * Both the instruction and data TLB miss get to this
514 * point to load the TLB.
516 * r11 - PTE high word value
517 * r12 - PTE low word value
519 * MMUCR - loaded with proper value when we get here
520 * Upon exit, we reload everything and RFI.
523 /* Combine RPN & ERPN an write WS 0 */
524 rlwimi r11,r12,0,0,31-PAGE_SHIFT
525 tlbwe r11,r13,PPC44x_TLB_XLAT
528 * Create WS1. This is the faulting address (EPN),
529 * page size, and valid flag.
531 li r11,PPC44x_TLB_VALID | PPC44x_TLBE_SIZE
532 /* Insert valid and page size */
533 rlwimi r10,r11,0,PPC44x_PTE_ADD_MASK_BIT,31
534 tlbwe r10,r13,PPC44x_TLB_PAGEID /* Write PAGEID */
537 li r10,0xf85 /* Mask to apply from PTE */
538 rlwimi r10,r12,29,30,30 /* DIRTY -> SW position */
539 and r11,r12,r10 /* Mask PTE bits to keep */
540 andi. r10,r12,_PAGE_USER /* User page ? */
541 beq 1f /* nope, leave U bits empty */
542 rlwimi r11,r11,3,26,28 /* yes, copy S bits to U */
543 rlwinm r11,r11,0,~PPC44x_TLB_SX /* Clear SX if User page */
544 1: tlbwe r11,r13,PPC44x_TLB_ATTRIB /* Write ATTRIB */
546 /* Done...restore registers and get out of here.
548 mfspr r11, SPRN_SPRG_RSCRATCH4
550 mfspr r13, SPRN_SPRG_RSCRATCH3
551 mfspr r12, SPRN_SPRG_RSCRATCH2
552 mfspr r11, SPRN_SPRG_RSCRATCH1
553 mfspr r10, SPRN_SPRG_RSCRATCH0
554 rfi /* Force context change */
556 /* TLB error interrupts for 476
558 #ifdef CONFIG_PPC_47x
559 START_EXCEPTION(DataTLBError47x)
560 mtspr SPRN_SPRG_WSCRATCH0,r10 /* Save some working registers */
561 mtspr SPRN_SPRG_WSCRATCH1,r11
562 mtspr SPRN_SPRG_WSCRATCH2,r12
563 mtspr SPRN_SPRG_WSCRATCH3,r13
565 mtspr SPRN_SPRG_WSCRATCH4,r11
566 mfspr r10,SPRN_DEAR /* Get faulting address */
568 /* If we are faulting a kernel address, we have to use the
569 * kernel page tables.
571 lis r11,PAGE_OFFSET@h
574 lis r11,swapper_pg_dir@h
575 ori r11,r11, swapper_pg_dir@l
576 li r12,0 /* MMUCR = 0 */
579 /* Get the PGD for the current thread and setup MMUCR */
580 3: mfspr r11,SPRN_SPRG3
582 mfspr r12,SPRN_PID /* Get PID */
583 #ifdef CONFIG_PPC_KUAP
585 beq 2f /* KUAP Fault */
587 4: mtspr SPRN_MMUCR,r12 /* Set MMUCR */
589 /* Mask of required permission bits. Note that while we
590 * do copy ESR:ST to _PAGE_RW position as trying to write
591 * to an RO page is pretty common, we don't do it with
592 * _PAGE_DIRTY. We could do it, but it's a fairly rare
593 * event so I'd rather take the overhead when it happens
594 * rather than adding an instruction here. We should measure
595 * whether the whole thing is worth it in the first place
596 * as we could avoid loading SPRN_ESR completely in the first
599 * TODO: Is it worth doing that mfspr & rlwimi in the first
600 * place or can we save a couple of instructions here ?
603 li r13,_PAGE_PRESENT|_PAGE_ACCESSED
604 rlwimi r13,r12,10,30,30
607 /* Compute pgdir/pmd offset */
608 rlwinm r12,r10,PPC44x_PGD_OFF_SHIFT,PPC44x_PGD_OFF_MASK_BIT,29
609 lwzx r11,r12,r11 /* Get pgd/pmd entry */
611 /* Word 0 is EPN,V,TS,DSIZ */
612 li r12,PPC47x_TLB0_VALID | PPC47x_TLBE_SIZE
613 rlwimi r10,r12,0,32-PAGE_SHIFT,31 /* Insert valid and page size*/
617 /* XXX can we do better ? Need to make sure tlbwe has established
618 * latch V bit in MMUCR0 before the PTE is loaded further down */
623 rlwinm. r12,r11,0,0,20 /* Extract pt base address */
624 /* Compute pte address */
625 rlwimi r12,r10,PPC44x_PTE_ADD_SHIFT,PPC44x_PTE_ADD_MASK_BIT,28
626 beq 2f /* Bail if no table */
627 lwz r11,0(r12) /* Get high word of pte entry */
629 /* XXX can we do better ? maybe insert a known 0 bit from r11 into the
630 * bottom of r12 to create a data dependency... We can also use r10
631 * as destination nowadays
636 lwz r12,4(r12) /* Get low word of pte entry */
638 andc. r13,r13,r12 /* Check permission */
640 /* Jump to common tlb load */
641 beq finish_tlb_load_47x
643 2: /* The bailout. Restore registers to pre-exception conditions
644 * and call the heavyweights to help us out.
646 mfspr r11,SPRN_SPRG_RSCRATCH4
648 mfspr r13,SPRN_SPRG_RSCRATCH3
649 mfspr r12,SPRN_SPRG_RSCRATCH2
650 mfspr r11,SPRN_SPRG_RSCRATCH1
651 mfspr r10,SPRN_SPRG_RSCRATCH0
654 /* Instruction TLB Error Interrupt */
656 * Nearly the same as above, except we get our
657 * information from different registers and bailout
658 * to a different point.
660 START_EXCEPTION(InstructionTLBError47x)
661 mtspr SPRN_SPRG_WSCRATCH0,r10 /* Save some working registers */
662 mtspr SPRN_SPRG_WSCRATCH1,r11
663 mtspr SPRN_SPRG_WSCRATCH2,r12
664 mtspr SPRN_SPRG_WSCRATCH3,r13
666 mtspr SPRN_SPRG_WSCRATCH4,r11
667 mfspr r10,SPRN_SRR0 /* Get faulting address */
669 /* If we are faulting a kernel address, we have to use the
670 * kernel page tables.
672 lis r11,PAGE_OFFSET@h
675 lis r11,swapper_pg_dir@h
676 ori r11,r11, swapper_pg_dir@l
677 li r12,0 /* MMUCR = 0 */
680 /* Get the PGD for the current thread and setup MMUCR */
681 3: mfspr r11,SPRN_SPRG_THREAD
683 mfspr r12,SPRN_PID /* Get PID */
684 #ifdef CONFIG_PPC_KUAP
686 beq 2f /* KUAP Fault */
688 4: mtspr SPRN_MMUCR,r12 /* Set MMUCR */
690 /* Make up the required permissions */
691 li r13,_PAGE_PRESENT | _PAGE_ACCESSED | _PAGE_EXEC
694 /* Compute pgdir/pmd offset */
695 rlwinm r12,r10,PPC44x_PGD_OFF_SHIFT,PPC44x_PGD_OFF_MASK_BIT,29
696 lwzx r11,r12,r11 /* Get pgd/pmd entry */
698 /* Word 0 is EPN,V,TS,DSIZ */
699 li r12,PPC47x_TLB0_VALID | PPC47x_TLBE_SIZE
700 rlwimi r10,r12,0,32-PAGE_SHIFT,31 /* Insert valid and page size*/
704 /* XXX can we do better ? Need to make sure tlbwe has established
705 * latch V bit in MMUCR0 before the PTE is loaded further down */
710 rlwinm. r12,r11,0,0,20 /* Extract pt base address */
711 /* Compute pte address */
712 rlwimi r12,r10,PPC44x_PTE_ADD_SHIFT,PPC44x_PTE_ADD_MASK_BIT,28
713 beq 2f /* Bail if no table */
715 lwz r11,0(r12) /* Get high word of pte entry */
716 /* XXX can we do better ? maybe insert a known 0 bit from r11 into the
717 * bottom of r12 to create a data dependency... We can also use r10
718 * as destination nowadays
723 lwz r12,4(r12) /* Get low word of pte entry */
725 andc. r13,r13,r12 /* Check permission */
727 /* Jump to common TLB load point */
728 beq finish_tlb_load_47x
730 2: /* The bailout. Restore registers to pre-exception conditions
731 * and call the heavyweights to help us out.
733 mfspr r11, SPRN_SPRG_RSCRATCH4
735 mfspr r13, SPRN_SPRG_RSCRATCH3
736 mfspr r12, SPRN_SPRG_RSCRATCH2
737 mfspr r11, SPRN_SPRG_RSCRATCH1
738 mfspr r10, SPRN_SPRG_RSCRATCH0
742 * Both the instruction and data TLB miss get to this
743 * point to load the TLB.
745 * r11 - PTE high word value
746 * r12 - PTE low word value
748 * MMUCR - loaded with proper value when we get here
749 * Upon exit, we reload everything and RFI.
752 /* Combine RPN & ERPN an write WS 1 */
753 rlwimi r11,r12,0,0,31-PAGE_SHIFT
756 /* And make up word 2 */
757 li r10,0xf85 /* Mask to apply from PTE */
758 rlwimi r10,r12,29,30,30 /* DIRTY -> SW position */
759 and r11,r12,r10 /* Mask PTE bits to keep */
760 andi. r10,r12,_PAGE_USER /* User page ? */
761 beq 1f /* nope, leave U bits empty */
762 rlwimi r11,r11,3,26,28 /* yes, copy S bits to U */
763 rlwinm r11,r11,0,~PPC47x_TLB2_SX /* Clear SX if User page */
766 /* Done...restore registers and get out of here.
768 mfspr r11, SPRN_SPRG_RSCRATCH4
770 mfspr r13, SPRN_SPRG_RSCRATCH3
771 mfspr r12, SPRN_SPRG_RSCRATCH2
772 mfspr r11, SPRN_SPRG_RSCRATCH1
773 mfspr r10, SPRN_SPRG_RSCRATCH0
776 #endif /* CONFIG_PPC_47x */
778 /* Debug Interrupt */
780 * This statement needs to exist at the end of the IVPR
781 * definition just in case you end up taking a debug
782 * exception within another exception.
793 * Adjust the machine check IVOR on 440A cores
795 _GLOBAL(__fixup_440A_mcheck)
796 li r3,MachineCheckA@l
802 * Init CPU state. This is called at boot time or for secondary CPUs
803 * to setup initial TLB entries, setup IVORs, etc...
806 _GLOBAL(init_cpu_state)
808 #ifdef CONFIG_PPC_47x
809 /* We use the PVR to differentiate 44x cores from 476 */
812 cmplwi cr0,r3,PVR_476FPE@h
814 cmplwi cr0,r3,PVR_476@h
816 cmplwi cr0,r3,PVR_476_ISS@h
818 #endif /* CONFIG_PPC_47x */
821 * In case the firmware didn't do it, we apply some workarounds
822 * that are good for all 440 core variants here
825 rlwinm r3,r3,0,0,27 /* disable icache prefetch */
832 * Set up the initial MMU state for 44x
834 * We are still executing code at the virtual address
835 * mappings set by the firmware for the base of RAM.
837 * We first invalidate all TLB entries but the one
838 * we are running from. We then load the KERNELBASE
839 * mappings so we can begin to use kernel addresses
840 * natively and so the interrupt vector locations are
841 * permanently pinned (necessary since Book E
842 * implementations always have translation enabled).
844 * TODO: Use the known TLB entry we are running from to
845 * determine which physical region we are located
846 * in. This can be used to determine where in RAM
847 * (on a shared CPU system) or PCI memory space
848 * (on a DRAMless system) we are located.
849 * For now, we assume a perfect world which means
850 * we are located at the base of DRAM (physical 0).
854 * Search TLB for entry that we are currently using.
855 * Invalidate all entries but the one we are using.
857 /* Load our current PID->MMUCR TID and MSR IS->MMUCR STS */
858 mfspr r3,SPRN_PID /* Get PID */
859 mfmsr r4 /* Get MSR */
860 andi. r4,r4,MSR_IS@l /* TS=1? */
861 beq wmmucr /* If not, leave STS=0 */
862 oris r3,r3,PPC44x_MMUCR_STS@h /* Set STS=1 */
863 wmmucr: mtspr SPRN_MMUCR,r3 /* Put MMUCR */
866 bcl 20,31,$+4 /* Find our address */
867 invstr: mflr r5 /* Make it accessible */
868 tlbsx r23,0,r5 /* Find entry we are in */
869 li r4,0 /* Start at TLB entry 0 */
870 li r3,0 /* Set PAGEID inval value */
871 1: cmpw r23,r4 /* Is this our entry? */
872 beq skpinv /* If so, skip the inval */
873 tlbwe r3,r4,PPC44x_TLB_PAGEID /* If not, inval the entry */
874 skpinv: addi r4,r4,1 /* Increment */
875 cmpwi r4,64 /* Are we done? */
876 bne 1b /* If not, repeat */
877 isync /* If so, context change */
880 * Configure and load pinned entry into TLB slot 63.
882 #ifdef CONFIG_NONSTATIC_KERNEL
884 * In case of a NONSTATIC_KERNEL we reuse the TLB XLAT
885 * entries of the initial mapping set by the boot loader.
886 * The XLAT entry is stored in r25
889 /* Read the XLAT entry for our current mapping */
890 tlbre r25,r23,PPC44x_TLB_XLAT
893 ori r3,r3,KERNELBASE@l
895 /* Use our current RPN entry */
900 ori r3,r3,PAGE_OFFSET@l
902 /* Kernel is at the base of RAM */
903 li r4, 0 /* Load the kernel physical address */
906 /* Load the kernel PID = 0 */
911 /* Initialize MMUCR */
917 clrrwi r3,r3,10 /* Mask off the effective page number */
918 ori r3,r3,PPC44x_TLB_VALID | PPC44x_TLB_256M
921 clrrwi r4,r4,10 /* Mask off the real page number */
922 /* ERPN is 0 for first 4GB page */
925 /* Added guarded bit to protect against speculative loads/stores */
927 ori r5,r5,(PPC44x_TLB_SW | PPC44x_TLB_SR | PPC44x_TLB_SX | PPC44x_TLB_G)
929 li r0,63 /* TLB slot 63 */
931 tlbwe r3,r0,PPC44x_TLB_PAGEID /* Load the pageid fields */
932 tlbwe r4,r0,PPC44x_TLB_XLAT /* Load the translation fields */
933 tlbwe r5,r0,PPC44x_TLB_ATTRIB /* Load the attrib/access fields */
935 /* Force context change */
944 /* If necessary, invalidate original entry we used */
948 tlbwe r6,r23,PPC44x_TLB_PAGEID
952 #ifdef CONFIG_PPC_EARLY_DEBUG_44x
953 /* Add UART mapping for early debug. */
956 lis r3,PPC44x_EARLY_DEBUG_VIRTADDR@h
957 ori r3,r3,PPC44x_TLB_VALID|PPC44x_TLB_TS|PPC44x_TLB_64K
960 lis r4,CONFIG_PPC_EARLY_DEBUG_44x_PHYSLOW@h
961 ori r4,r4,CONFIG_PPC_EARLY_DEBUG_44x_PHYSHIGH
964 li r5,(PPC44x_TLB_SW|PPC44x_TLB_SR|PPC44x_TLB_I|PPC44x_TLB_G)
965 li r0,62 /* TLB slot 0 */
967 tlbwe r3,r0,PPC44x_TLB_PAGEID
968 tlbwe r4,r0,PPC44x_TLB_XLAT
969 tlbwe r5,r0,PPC44x_TLB_ATTRIB
971 /* Force context change */
973 #endif /* CONFIG_PPC_EARLY_DEBUG_44x */
975 /* Establish the interrupt vector offsets */
976 SET_IVOR(0, CriticalInput);
977 SET_IVOR(1, MachineCheck);
978 SET_IVOR(2, DataStorage);
979 SET_IVOR(3, InstructionStorage);
980 SET_IVOR(4, ExternalInput);
981 SET_IVOR(5, Alignment);
982 SET_IVOR(6, Program);
983 SET_IVOR(7, FloatingPointUnavailable);
984 SET_IVOR(8, SystemCall);
985 SET_IVOR(9, AuxillaryProcessorUnavailable);
986 SET_IVOR(10, Decrementer);
987 SET_IVOR(11, FixedIntervalTimer);
988 SET_IVOR(12, WatchdogTimer);
989 SET_IVOR(13, DataTLBError44x);
990 SET_IVOR(14, InstructionTLBError44x);
991 SET_IVOR(15, DebugCrit);
996 #ifdef CONFIG_PPC_47x
1000 /* Entry point for secondary 47x processors */
1001 _GLOBAL(start_secondary_47x)
1002 mr r24,r3 /* CPU number */
1006 /* Now we need to bolt the rest of kernel memory which
1007 * is done in C code. We must be careful because our task
1008 * struct or our stack can (and will probably) be out
1009 * of reach of the initial 256M TLB entry, so we use a
1010 * small temporary stack in .bss for that. This works
1011 * because only one CPU at a time can be in this code
1013 lis r1,temp_boot_stack@h
1014 ori r1,r1,temp_boot_stack@l
1015 addi r1,r1,1024-STACK_FRAME_MIN_SIZE
1018 bl mmu_init_secondary
1020 /* Now we can get our task struct and real stack pointer */
1022 /* Get current's stack and current */
1023 lis r2,secondary_current@ha
1024 lwz r2,secondary_current@l(r2)
1025 lwz r1,TASK_STACK(r2)
1027 /* Current stack pointer */
1028 addi r1,r1,THREAD_SIZE-STACK_FRAME_MIN_SIZE
1032 /* Kernel stack for exception entry in SPRG3 */
1033 addi r4,r2,THREAD /* init task's THREAD */
1038 #endif /* CONFIG_SMP */
1041 * Set up the initial MMU state for 44x
1043 * We are still executing code at the virtual address
1044 * mappings set by the firmware for the base of RAM.
1048 /* Load our current PID->MMUCR TID and MSR IS->MMUCR STS */
1049 mfspr r3,SPRN_PID /* Get PID */
1050 mfmsr r4 /* Get MSR */
1051 andi. r4,r4,MSR_IS@l /* TS=1? */
1052 beq 1f /* If not, leave STS=0 */
1053 oris r3,r3,PPC47x_MMUCR_STS@h /* Set STS=1 */
1054 1: mtspr SPRN_MMUCR,r3 /* Put MMUCR */
1057 /* Find the entry we are running from */
1069 /* Initialize MMUCR */
1074 clear_all_utlb_entries:
1076 #; Set initial values.
1083 #; Align the loop to speed things up.
1094 bne clear_utlb_entry
1098 bne clear_utlb_entry
1100 #; Restore original entry.
1102 oris r23,r23,0x8000 /* specify the way */
1108 * Configure and load pinned entry into TLB for the kernel core
1111 lis r3,PAGE_OFFSET@h
1112 ori r3,r3,PAGE_OFFSET@l
1114 /* Load the kernel PID = 0 */
1120 clrrwi r3,r3,12 /* Mask off the effective page number */
1121 ori r3,r3,PPC47x_TLB0_VALID | PPC47x_TLB0_256M
1123 /* Word 1 - use r25. RPN is the same as the original entry */
1127 ori r5,r5,PPC47x_TLB2_S_RWX
1129 ori r5,r5,PPC47x_TLB2_M
1132 /* We write to way 0 and bolted 0 */
1139 * Configure SSPCR, ISPCR and USPCR for now to search everything, we can fix
1142 LOAD_REG_IMMEDIATE(r3, 0x9abcdef0)
1145 LOAD_REG_IMMEDIATE(r3, 0x12345670)
1148 /* Force context change */
1157 /* Invalidate original entry we used */
1159 rlwinm r24,r24,0,21,19 /* clear the "valid" bit */
1164 isync /* Clear out the shadow TLB entries */
1166 #ifdef CONFIG_PPC_EARLY_DEBUG_44x
1167 /* Add UART mapping for early debug. */
1170 lis r3,PPC44x_EARLY_DEBUG_VIRTADDR@h
1171 ori r3,r3,PPC47x_TLB0_VALID | PPC47x_TLB0_TS | PPC47x_TLB0_1M
1174 lis r4,CONFIG_PPC_EARLY_DEBUG_44x_PHYSLOW@h
1175 ori r4,r4,CONFIG_PPC_EARLY_DEBUG_44x_PHYSHIGH
1178 li r5,(PPC47x_TLB2_S_RW | PPC47x_TLB2_IMG)
1180 /* Bolted in way 0, bolt slot 5, we -hope- we don't hit the same
1181 * congruence class as the kernel, we need to make sure of it at
1189 /* Force context change */
1191 #endif /* CONFIG_PPC_EARLY_DEBUG_44x */
1193 /* Establish the interrupt vector offsets */
1194 SET_IVOR(0, CriticalInput);
1195 SET_IVOR(1, MachineCheckA);
1196 SET_IVOR(2, DataStorage);
1197 SET_IVOR(3, InstructionStorage);
1198 SET_IVOR(4, ExternalInput);
1199 SET_IVOR(5, Alignment);
1200 SET_IVOR(6, Program);
1201 SET_IVOR(7, FloatingPointUnavailable);
1202 SET_IVOR(8, SystemCall);
1203 SET_IVOR(9, AuxillaryProcessorUnavailable);
1204 SET_IVOR(10, Decrementer);
1205 SET_IVOR(11, FixedIntervalTimer);
1206 SET_IVOR(12, WatchdogTimer);
1207 SET_IVOR(13, DataTLBError47x);
1208 SET_IVOR(14, InstructionTLBError47x);
1209 SET_IVOR(15, DebugCrit);
1211 /* We configure icbi to invalidate 128 bytes at a time since the
1212 * current 32-bit kernel code isn't too happy with icache != dcache
1213 * block size. We also disable the BTAC as this can cause errors
1214 * in some circumstances (see IBM Erratum 47).
1222 #endif /* CONFIG_PPC_47x */
1225 * Here we are back to code that is common between 44x and 47x
1227 * We proceed to further kernel initialization and return to the
1231 /* Establish the interrupt vector base */
1232 lis r4,interrupt_base@h /* IVPR only uses the high 16-bits */
1236 * If the kernel was loaded at a non-zero 256 MB page, we need to
1237 * mask off the most significant 4 bits to get the relative address
1238 * from the start of physical memory
1240 rlwinm r22,r22,0,4,31
1241 addis r22,r22,PAGE_OFFSET@h
1251 #endif /* CONFIG_SMP */