2 * Copyright (c) 1995-1996 Gary Thomas <gdt@linuxppc.org>
3 * Initial PowerPC version.
4 * Copyright (c) 1996 Cort Dougan <cort@cs.nmt.edu>
6 * Copyright (c) 1996 Paul Mackerras <paulus@cs.anu.edu.au>
7 * Low-level exception handers, MMU support, and rewrite.
8 * Copyright (c) 1997 Dan Malek <dmalek@jlc.net>
9 * PowerPC 8xx modifications.
10 * Copyright (c) 1998-1999 TiVo, Inc.
11 * PowerPC 403GCX modifications.
12 * Copyright (c) 1999 Grant Erickson <grant@lcse.umn.edu>
13 * PowerPC 403GCX/405GP modifications.
14 * Copyright 2000 MontaVista Software Inc.
15 * PPC405 modifications
16 * PowerPC 403GCX/405GP modifications.
17 * Author: MontaVista Software, Inc.
18 * frank_rowand@mvista.com or source@mvista.com
19 * debbie_chu@mvista.com
22 * Module name: head_4xx.S
25 * Kernel execution entry point code.
27 * This program is free software; you can redistribute it and/or
28 * modify it under the terms of the GNU General Public License
29 * as published by the Free Software Foundation; either version
30 * 2 of the License, or (at your option) any later version.
34 #include <linux/config.h>
35 #include <asm/processor.h>
38 #include <asm/pgtable.h>
39 #include <asm/ibm4xx.h>
40 #include <asm/cputable.h>
41 #include <asm/thread_info.h>
42 #include <asm/ppc_asm.h>
43 #include <asm/offsets.h>
45 /* As with the other PowerPC ports, it is expected that when code
46 * execution begins here, the following registers contain valid, yet
47 * optional, information:
49 * r3 - Board info structure pointer (DRAM, frequency, MAC address, etc.)
50 * r4 - Starting address of the init RAM disk
51 * r5 - Ending address of the init RAM disk
52 * r6 - Start of kernel command line string (e.g. "mem=96m")
53 * r7 - End of kernel command line string
55 * This is all going to change RSN when we add bi_recs....... -- Dan
61 /* Save parameters we are passed.
69 /* We have to turn on the MMU right away so we get cache modes
74 /* We now have the lower 16 Meg mapped into TLB entries, and the caches
79 ori r0,r0,MSR_KERNEL@l
82 ori r0,r0,start_here@l
86 b . /* prevent prefetch past rfi */
89 * This area is used for temporarily saving registers during the
90 * critical exception prolog.
118 * Exception vector entry code. This code runs with address translation
119 * turned off (i.e. using physical addresses). We assume SPRG3 has the
120 * physical address of the current task thread_struct.
121 * Note that we have to have decremented r1 before we write to any fields
122 * of the exception frame, since a critical interrupt could occur at any
123 * time, and it will write to the area immediately below the current r1.
125 #define NORMAL_EXCEPTION_PROLOG \
126 mtspr SPRN_SPRG0,r10; /* save two registers to work with */\
127 mtspr SPRN_SPRG1,r11; \
128 mtspr SPRN_SPRG2,r1; \
129 mfcr r10; /* save CR in r10 for now */\
130 mfspr r11,SPRN_SRR1; /* check whether user or kernel */\
131 andi. r11,r11,MSR_PR; \
133 mfspr r1,SPRG3; /* if from user, start at top of */\
134 lwz r1,THREAD_INFO-THREAD(r1); /* this thread's kernel stack */\
135 addi r1,r1,THREAD_SIZE; \
136 1: subi r1,r1,INT_FRAME_SIZE; /* Allocate an exception frame */\
138 stw r10,_CCR(r11); /* save various registers */\
139 stw r12,GPR12(r11); \
142 stw r10,GPR10(r11); \
144 stw r12,GPR11(r11); \
146 stw r10,_LINK(r11); \
152 rlwinm r9,r9,0,14,12; /* clear MSR_WE (necessary?) */\
154 SAVE_4GPRS(3, r11); \
158 * Exception prolog for critical exceptions. This is a little different
159 * from the normal exception prolog above since a critical exception
160 * can potentially occur at any point during normal exception processing.
161 * Thus we cannot use the same SPRG registers as the normal prolog above.
162 * Instead we use a couple of words of memory at low physical addresses.
163 * This is OK since we don't support SMP on these processors.
165 #define CRITICAL_EXCEPTION_PROLOG \
166 stw r10,crit_r10@l(0); /* save two registers to work with */\
167 stw r11,crit_r11@l(0); \
169 stw r10,crit_sprg0@l(0); \
171 stw r10,crit_sprg1@l(0); \
173 stw r10,crit_sprg4@l(0); \
175 stw r10,crit_sprg5@l(0); \
177 stw r10,crit_sprg6@l(0); \
179 stw r10,crit_sprg7@l(0); \
180 mfspr r10,SPRN_PID; \
181 stw r10,crit_pid@l(0); \
183 stw r10,crit_srr0@l(0); \
185 stw r10,crit_srr1@l(0); \
186 mfcr r10; /* save CR in r10 for now */\
187 mfspr r11,SPRN_SRR3; /* check whether user or kernel */\
188 andi. r11,r11,MSR_PR; \
189 lis r11,critical_stack_top@h; \
190 ori r11,r11,critical_stack_top@l; \
192 /* COMING FROM USER MODE */ \
193 mfspr r11,SPRG3; /* if from user, start at top of */\
194 lwz r11,THREAD_INFO-THREAD(r11); /* this thread's kernel stack */\
195 addi r11,r11,THREAD_SIZE; \
196 1: subi r11,r11,INT_FRAME_SIZE; /* Allocate an exception frame */\
198 stw r10,_CCR(r11); /* save various registers */\
199 stw r12,GPR12(r11); \
202 stw r10,_LINK(r11); \
203 mfspr r12,SPRN_DEAR; /* save DEAR and ESR in the frame */\
204 stw r12,_DEAR(r11); /* since they may have had stuff */\
205 mfspr r9,SPRN_ESR; /* in them at the point where the */\
206 stw r9,_ESR(r11); /* exception was taken */\
212 rlwinm r9,r9,0,14,12; /* clear MSR_WE (necessary?) */\
214 SAVE_4GPRS(3, r11); \
218 * State at this point:
219 * r9 saved in stack frame, now saved SRR3 & ~MSR_WE
220 * r10 saved in crit_r10 and in stack frame, trashed
221 * r11 saved in crit_r11 and in stack frame,
222 * now phys stack/exception frame pointer
223 * r12 saved in stack frame, now saved SRR2
224 * SPRG0,1,4,5,6,7 saved in crit_sprg0,1,4,5,6,7
225 * PID saved in crit_pid
226 * SRR0,1 saved in crit_srr0,1
227 * CR saved in stack frame, CR0.EQ = !SRR3.PR
228 * LR, DEAR, ESR in stack frame
229 * r1 saved in stack frame, now virt stack/excframe pointer
230 * r0, r3-r8 saved in stack frame
236 #define START_EXCEPTION(n, label) \
240 #define EXCEPTION(n, label, hdlr, xfer) \
241 START_EXCEPTION(n, label); \
242 NORMAL_EXCEPTION_PROLOG; \
243 addi r3,r1,STACK_FRAME_OVERHEAD; \
246 #define CRITICAL_EXCEPTION(n, label, hdlr) \
247 START_EXCEPTION(n, label); \
248 CRITICAL_EXCEPTION_PROLOG; \
249 addi r3,r1,STACK_FRAME_OVERHEAD; \
250 EXC_XFER_TEMPLATE(hdlr, n+2, (MSR_KERNEL & ~(MSR_ME|MSR_DE|MSR_CE)), \
251 NOCOPY, crit_transfer_to_handler, \
254 #define EXC_XFER_TEMPLATE(hdlr, trap, msr, copyee, tfer, ret) \
264 #define COPY_EE(d, s) rlwimi d,s,0,16,16
267 #define EXC_XFER_STD(n, hdlr) \
268 EXC_XFER_TEMPLATE(hdlr, n, MSR_KERNEL, NOCOPY, transfer_to_handler_full, \
269 ret_from_except_full)
271 #define EXC_XFER_LITE(n, hdlr) \
272 EXC_XFER_TEMPLATE(hdlr, n+1, MSR_KERNEL, NOCOPY, transfer_to_handler, \
275 #define EXC_XFER_EE(n, hdlr) \
276 EXC_XFER_TEMPLATE(hdlr, n, MSR_KERNEL, COPY_EE, transfer_to_handler_full, \
277 ret_from_except_full)
279 #define EXC_XFER_EE_LITE(n, hdlr) \
280 EXC_XFER_TEMPLATE(hdlr, n+1, MSR_KERNEL, COPY_EE, transfer_to_handler, \
285 * 0x0100 - Critical Interrupt Exception
287 CRITICAL_EXCEPTION(0x0100, CriticalInterrupt, UnknownException)
290 * 0x0200 - Machine Check Exception
292 CRITICAL_EXCEPTION(0x0200, MachineCheck, MachineCheckException)
295 * 0x0300 - Data Storage Exception
296 * This happens for just a few reasons. U0 set (but we don't do that),
297 * or zone protection fault (user violation, write to protected page).
298 * If this is just an update of modified status, we do that quickly
299 * and exit. Otherwise, we call heavywight functions to do the work.
301 START_EXCEPTION(0x0300, DataStorage)
302 mtspr SPRG0, r10 /* Save some working registers */
320 /* First, check if it was a zone fault (which means a user
321 * tried to access a kernel or read-protected page - always
322 * a SEGV). All other faults here must be stores, so no
323 * need to check ESR_DST as well. */
325 andis. r10, r10, ESR_DIZ@h
328 mfspr r10, SPRN_DEAR /* Get faulting address */
330 /* If we are faulting a kernel address, we have to use the
331 * kernel page tables.
333 andis. r11, r10, 0x8000
335 lis r11, swapper_pg_dir@h
336 ori r11, r11, swapper_pg_dir@l
338 mtspr SPRN_PID, r9 /* TLB will have 0 TID */
341 /* Get the PGD for the current thread.
348 rlwimi r11, r10, 12, 20, 29 /* Create L1 (pgdir/pmd) address */
349 lwz r11, 0(r11) /* Get L1 entry */
350 rlwinm. r12, r11, 0, 0, 19 /* Extract L2 (pte) base address */
351 beq 2f /* Bail if no table */
353 rlwimi r12, r10, 22, 20, 29 /* Compute PTE address */
354 lwz r11, 0(r12) /* Get Linux PTE */
356 andi. r9, r11, _PAGE_RW /* Is it writeable? */
357 beq 2f /* Bail if not */
361 ori r11, r11, _PAGE_DIRTY|_PAGE_ACCESSED|_PAGE_HWWRITE
362 stw r11, 0(r12) /* Update Linux page table */
364 /* Most of the Linux PTE is ready to load into the TLB LO.
365 * We set ZSEL, where only the LS-bit determines user access.
366 * We set execute, because we don't have the granularity to
367 * properly set this at the page level (Linux problem).
368 * If shared is set, we cause a zero PID->TID load.
369 * Many of these bits are software only. Bits we don't set
370 * here we (properly should) assume have the appropriate value.
373 andc r11, r11, r12 /* Make sure 20, 21 are zero */
375 /* find the TLB index that caused the fault. It has to be here.
379 tlbwe r11, r9, TLB_DATA /* Load TLB LO */
381 /* Done...restore registers and get out of here.
401 rfi /* Should sync shadow TLBs */
402 b . /* prevent prefetch past rfi */
405 /* The bailout. Restore registers to pre-exception conditions
406 * and call the heavyweights to help us out.
428 * 0x0400 - Instruction Storage Exception
429 * This is caused by a fetch from non-execute or guarded pages.
431 START_EXCEPTION(0x0400, InstructionAccess)
432 NORMAL_EXCEPTION_PROLOG
433 mr r4,r12 /* Pass SRR0 as arg2 */
434 li r5,0 /* Pass zero as arg3 */
435 addi r3,r1,STACK_FRAME_OVERHEAD
436 EXC_XFER_EE_LITE(0x400, do_page_fault)
438 /* 0x0500 - External Interrupt Exception */
439 EXCEPTION(0x0500, HardwareInterrupt, do_IRQ, EXC_XFER_LITE)
441 /* 0x0600 - Alignment Exception */
442 START_EXCEPTION(0x0600, Alignment)
443 NORMAL_EXCEPTION_PROLOG
444 mfspr r4,SPRN_DEAR /* Grab the DEAR and save it */
446 addi r3,r1,STACK_FRAME_OVERHEAD
447 EXC_XFER_EE(0x600, AlignmentException)
449 /* 0x0700 - Program Exception */
450 START_EXCEPTION(0x0700, ProgramCheck)
451 NORMAL_EXCEPTION_PROLOG
452 mfspr r4,SPRN_ESR /* Grab the ESR and save it */
454 addi r3,r1,STACK_FRAME_OVERHEAD
455 EXC_XFER_EE(0x700, ProgramCheckException)
457 EXCEPTION(0x0800, Trap_08, UnknownException, EXC_XFER_EE)
458 EXCEPTION(0x0900, Trap_09, UnknownException, EXC_XFER_EE)
459 EXCEPTION(0x0A00, Trap_0A, UnknownException, EXC_XFER_EE)
460 EXCEPTION(0x0B00, Trap_0B, UnknownException, EXC_XFER_EE)
462 /* 0x0C00 - System Call Exception */
463 START_EXCEPTION(0x0C00, SystemCall)
464 NORMAL_EXCEPTION_PROLOG
465 EXC_XFER_EE_LITE(0xc00, DoSyscall)
467 EXCEPTION(0x0D00, Trap_0D, UnknownException, EXC_XFER_EE)
468 EXCEPTION(0x0E00, Trap_0E, UnknownException, EXC_XFER_EE)
469 EXCEPTION(0x0F00, Trap_0F, UnknownException, EXC_XFER_EE)
471 /* 0x1000 - Programmable Interval Timer (PIT) Exception */
472 START_EXCEPTION(0x1000, Decrementer)
473 NORMAL_EXCEPTION_PROLOG
475 mtspr SPRN_TSR,r0 /* Clear the PIT exception */
476 addi r3,r1,STACK_FRAME_OVERHEAD
477 EXC_XFER_LITE(0x1000, timer_interrupt)
481 * FIT and WDT handlers are not implemented yet.
484 /* 0x1010 - Fixed Interval Timer (FIT) Exception
486 STND_EXCEPTION(0x1010, FITException, UnknownException)
488 /* 0x1020 - Watchdog Timer (WDT) Exception
491 CRITICAL_EXCEPTION(0x1020, WDTException, UnknownException)
494 /* 0x1100 - Data TLB Miss Exception
495 * As the name implies, translation is not in the MMU, so search the
496 * page tables and fix it. The only purpose of this function is to
497 * load TLB entries from the page table if they exist.
499 START_EXCEPTION(0x1100, DTLBMiss)
500 mtspr SPRG0, r10 /* Save some working registers */
517 mfspr r10, SPRN_DEAR /* Get faulting address */
519 /* If we are faulting a kernel address, we have to use the
520 * kernel page tables.
522 andis. r11, r10, 0x8000
524 lis r11, swapper_pg_dir@h
525 ori r11, r11, swapper_pg_dir@l
527 mtspr SPRN_PID, r9 /* TLB will have 0 TID */
530 /* Get the PGD for the current thread.
537 rlwimi r11, r10, 12, 20, 29 /* Create L1 (pgdir/pmd) address */
538 lwz r12, 0(r11) /* Get L1 entry */
539 andi. r9, r12, _PMD_PRESENT /* Check if it points to a PTE page */
540 beq 2f /* Bail if no table */
542 rlwimi r12, r10, 22, 20, 29 /* Compute PTE address */
543 lwz r11, 0(r12) /* Get Linux PTE */
544 andi. r9, r11, _PAGE_PRESENT
547 ori r11, r11, _PAGE_ACCESSED
550 /* Create TLB tag. This is the faulting address plus a static
551 * set of bits. These are size, valid, E, U0.
554 rlwimi r10, r12, 0, 20, 31
558 2: /* Check for possible large-page pmd entry */
559 rlwinm. r9, r12, 2, 22, 24
562 /* Create TLB tag. This is the faulting address, plus a static
563 * set of bits (valid, E, U0) plus the size from the PMD.
566 rlwimi r10, r9, 0, 20, 31
572 /* The bailout. Restore registers to pre-exception conditions
573 * and call the heavyweights to help us out.
594 /* 0x1200 - Instruction TLB Miss Exception
595 * Nearly the same as above, except we get our information from different
596 * registers and bailout to a different point.
598 START_EXCEPTION(0x1200, ITLBMiss)
599 mtspr SPRG0, r10 /* Save some working registers */
616 mfspr r10, SRR0 /* Get faulting address */
618 /* If we are faulting a kernel address, we have to use the
619 * kernel page tables.
621 andis. r11, r10, 0x8000
623 lis r11, swapper_pg_dir@h
624 ori r11, r11, swapper_pg_dir@l
626 mtspr SPRN_PID, r9 /* TLB will have 0 TID */
629 /* Get the PGD for the current thread.
636 rlwimi r11, r10, 12, 20, 29 /* Create L1 (pgdir/pmd) address */
637 lwz r12, 0(r11) /* Get L1 entry */
638 andi. r9, r12, _PMD_PRESENT /* Check if it points to a PTE page */
639 beq 2f /* Bail if no table */
641 rlwimi r12, r10, 22, 20, 29 /* Compute PTE address */
642 lwz r11, 0(r12) /* Get Linux PTE */
643 andi. r9, r11, _PAGE_PRESENT
646 ori r11, r11, _PAGE_ACCESSED
649 /* Create TLB tag. This is the faulting address plus a static
650 * set of bits. These are size, valid, E, U0.
653 rlwimi r10, r12, 0, 20, 31
657 2: /* Check for possible large-page pmd entry */
658 rlwinm. r9, r12, 2, 22, 24
661 /* Create TLB tag. This is the faulting address, plus a static
662 * set of bits (valid, E, U0) plus the size from the PMD.
665 rlwimi r10, r9, 0, 20, 31
671 /* The bailout. Restore registers to pre-exception conditions
672 * and call the heavyweights to help us out.
693 EXCEPTION(0x1300, Trap_13, UnknownException, EXC_XFER_EE)
694 EXCEPTION(0x1400, Trap_14, UnknownException, EXC_XFER_EE)
695 EXCEPTION(0x1500, Trap_15, UnknownException, EXC_XFER_EE)
696 EXCEPTION(0x1600, Trap_16, UnknownException, EXC_XFER_EE)
697 #ifdef CONFIG_IBM405_ERR51
698 /* 405GP errata 51 */
699 START_EXCEPTION(0x1700, Trap_17)
702 EXCEPTION(0x1700, Trap_17, UnknownException, EXC_XFER_EE)
704 EXCEPTION(0x1800, Trap_18, UnknownException, EXC_XFER_EE)
705 EXCEPTION(0x1900, Trap_19, UnknownException, EXC_XFER_EE)
706 EXCEPTION(0x1A00, Trap_1A, UnknownException, EXC_XFER_EE)
707 EXCEPTION(0x1B00, Trap_1B, UnknownException, EXC_XFER_EE)
708 EXCEPTION(0x1C00, Trap_1C, UnknownException, EXC_XFER_EE)
709 EXCEPTION(0x1D00, Trap_1D, UnknownException, EXC_XFER_EE)
710 EXCEPTION(0x1E00, Trap_1E, UnknownException, EXC_XFER_EE)
711 EXCEPTION(0x1F00, Trap_1F, UnknownException, EXC_XFER_EE)
713 /* 0x2000 - Debug Exception
715 START_EXCEPTION(0x2000, DebugTrap)
716 CRITICAL_EXCEPTION_PROLOG
719 * If this is a single step or branch-taken exception in an
720 * exception entry sequence, it was probably meant to apply to
721 * the code where the exception occurred (since exception entry
722 * doesn't turn off DE automatically). We simulate the effect
723 * of turning off DE on entry to an exception handler by turning
724 * off DE in the SRR3 value and clearing the debug status.
726 mfspr r10,SPRN_DBSR /* check single-step/branch taken */
727 andis. r10,r10,(DBSR_IC|DBSR_BT)@h
729 andi. r0,r9,MSR_IR|MSR_PR /* check supervisor + MMU off */
730 beq 2f /* branch if we need to fix it up... */
732 /* continue normal handling for a critical exception... */
733 1: mfspr r4,SPRN_DBSR
734 addi r3,r1,STACK_FRAME_OVERHEAD
735 EXC_XFER_TEMPLATE(DebugException, 0x2002, \
736 (MSR_KERNEL & ~(MSR_ME|MSR_DE|MSR_CE)), \
737 NOCOPY, crit_transfer_to_handler, ret_from_crit_exc)
739 /* here it looks like we got an inappropriate debug exception. */
740 2: rlwinm r9,r9,0,~MSR_DE /* clear DE in the SRR3 value */
741 mtspr SPRN_DBSR,r10 /* clear the IC/BT debug intr status */
742 /* restore state and get out */
751 lwz r10,crit_r10@l(0)
752 lwz r11,crit_r11@l(0)
758 * The other Data TLB exceptions bail out to this point
759 * if they can't resolve the lightweight TLB fault.
762 NORMAL_EXCEPTION_PROLOG
763 mfspr r5,SPRN_ESR /* Grab the ESR, save it, pass arg3 */
765 mfspr r4,SPRN_DEAR /* Grab the DEAR, save it, pass arg2 */
767 addi r3,r1,STACK_FRAME_OVERHEAD
768 EXC_XFER_EE_LITE(0x300, do_page_fault)
770 /* Other PowerPC processors, namely those derived from the 6xx-series
771 * have vectors from 0x2100 through 0x2F00 defined, but marked as reserved.
772 * However, for the 4xx-series processors these are neither defined nor
776 /* Damn, I came up one instruction too many to fit into the
777 * exception space :-). Both the instruction and data TLB
778 * miss get to this point to load the TLB.
779 * r10 - TLB_TAG value
781 * r12, r9 - avilable to use
782 * PID - loaded with proper value when we get here
783 * Upon exit, we reload everything and RFI.
784 * Actually, it will fit now, but oh well.....a common place
790 /* load the next available TLB index.
792 lwz r9, tlb_4xx_index@l(0)
794 andi. r9, r9, (PPC4XX_TLB_SIZE-1)
795 stw r9, tlb_4xx_index@l(0)
799 * Clear out the software-only bits in the PTE to generate the
800 * TLB_DATA value. These are the bottom 2 bits of the RPM, the
801 * top 3 bits of the zone field, and M.
806 tlbwe r11, r9, TLB_DATA /* Load TLB LO */
807 tlbwe r10, r9, TLB_TAG /* Load TLB HI */
809 /* Done...restore registers and get out of here.
829 rfi /* Should sync shadow TLBs */
830 b . /* prevent prefetch past rfi */
832 /* extern void giveup_fpu(struct task_struct *prev)
834 * The PowerPC 4xx family of processors do not have an FPU, so this just
840 /* This is where the main kernel code starts.
846 ori r2,r2,init_task@l
848 /* ptr to phys current thread */
850 addi r4,r4,THREAD /* init task's THREAD */
854 lis r1,init_thread_union@ha
855 addi r1,r1,init_thread_union@l
857 stwu r0,THREAD_SIZE-STACK_FRAME_OVERHEAD(r1)
859 bl early_init /* We have to do this with MMU on */
862 * Decide what sort of machine this is and initialize the MMU.
872 /* Go back to running unmapped so we can load up new values
873 * and change to using our exception vectors.
874 * On the 4xx, all we have to do is invalidate the TLB to clear
875 * the old 16M byte TLB mappings.
880 lis r3,(MSR_KERNEL & ~(MSR_IR|MSR_DR))@h
881 ori r3,r3,(MSR_KERNEL & ~(MSR_IR|MSR_DR))@l
885 b . /* prevent prefetch past rfi */
887 /* Load up the kernel context */
889 sync /* Flush to memory before changing TLB */
891 isync /* Flush shadow TLBs */
893 /* set up the PTE pointers for the Abatron bdiGDB.
895 lis r6, swapper_pg_dir@h
896 ori r6, r6, swapper_pg_dir@l
897 lis r5, abatron_pteptrs@h
898 ori r5, r5, abatron_pteptrs@l
899 stw r5, 0xf0(r0) /* Must match your Abatron config file */
903 /* Now turn on the MMU for real! */
905 ori r4,r4,MSR_KERNEL@l
906 lis r3,start_kernel@h
907 ori r3,r3,start_kernel@l
910 rfi /* enable MMU and jump to start_kernel */
911 b . /* prevent prefetch past rfi */
913 /* Set up the initial MMU state so we can do the first level of
914 * kernel initialization. This maps the first 16 MBytes of memory 1:1
915 * virtual to physical and more importantly sets the cache mode.
918 tlbia /* Invalidate all TLB entries */
921 /* We should still be executing code at physical address 0x0000xxxx
922 * at this point. However, start_here is at virtual address
923 * 0xC000xxxx. So, set up a TLB mapping to cover this once
924 * translation is enabled.
927 lis r3,KERNELBASE@h /* Load the kernel virtual address */
928 ori r3,r3,KERNELBASE@l
929 tophys(r4,r3) /* Load the kernel physical address */
931 iccci r0,r3 /* Invalidate the i-cache before use */
933 /* Load the kernel PID.
939 /* Configure and load two entries into TLB slots 62 and 63.
940 * In case we are pinning TLBs, these are reserved in by the
941 * other TLB functions. If not reserving, then it doesn't
942 * matter where they are loaded.
944 clrrwi r4,r4,10 /* Mask off the real page number */
945 ori r4,r4,(TLB_WR | TLB_EX) /* Set the write and execute bits */
947 clrrwi r3,r3,10 /* Mask off the effective page number */
948 ori r3,r3,(TLB_VALID | TLB_PAGESZ(PAGESZ_16M))
950 li r0,63 /* TLB slot 63 */
952 tlbwe r4,r0,TLB_DATA /* Load the data portion of the entry */
953 tlbwe r3,r0,TLB_TAG /* Load the tag portion of the entry */
955 #if defined(CONFIG_SERIAL_TEXT_DEBUG) && defined(SERIAL_DEBUG_IO_BASE)
957 /* Load a TLB entry for the UART, so that ppc4xx_progress() can use
958 * the UARTs nice and early. We use a 4k real==virtual mapping. */
960 lis r3,SERIAL_DEBUG_IO_BASE@h
961 ori r3,r3,SERIAL_DEBUG_IO_BASE@l
964 ori r4,r4,(TLB_WR|TLB_I|TLB_M|TLB_G)
967 ori r3,r3,(TLB_VALID | TLB_PAGESZ(PAGESZ_4K))
969 li r0,0 /* TLB slot 0 */
972 #endif /* CONFIG_SERIAL_DEBUG_TEXT && SERIAL_DEBUG_IO_BASE */
976 /* Establish the exception vector base
978 lis r4,KERNELBASE@h /* EVPR only uses the high 16-bits */
979 tophys(r0,r4) /* Use the physical address */
986 oris r13,r13,DBCR0_RST_SYSTEM@h
991 #ifdef CONFIG_BDI_SWITCH
992 /* Context switch the PTE pointer for the Abatron BDI2000.
993 * The PGDIR is the second parameter.
1001 isync /* Need an isync to flush shadow */
1002 /* TLBs after changing PID */
1005 /* We put a few things here that have to be page-aligned. This stuff
1006 * goes at the beginning of the data segment, which is page-aligned.
1010 _GLOBAL(empty_zero_page)
1012 _GLOBAL(swapper_pg_dir)
1016 /* Stack for handling critical exceptions from kernel mode */
1018 critical_stack_bottom:
1023 /* This space gets a copy of optional info passed to us by the bootstrap
1024 * which is used to pass parameters into the kernel like root=/dev/sda1, etc.
1029 /* Room for two PTE pointers, usually the kernel and current user pointers
1030 * to their respective root page table.