3 * Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
5 * Rewritten by Cort Dougan (cort@cs.nmt.edu) for PReP
6 * Copyright (C) 1996 Cort Dougan <cort@cs.nmt.edu>
7 * Adapted for Power Macintosh by Paul Mackerras.
8 * Low-level exception handlers and MMU support
9 * rewritten by Paul Mackerras.
10 * Copyright (C) 1996 Paul Mackerras.
11 * MPC8xx modifications Copyright (C) 1997 Dan Malek (dmalek@jlc.net).
12 * Amiga/APUS changes by Jesper Skov (jskov@cygnus.co.uk).
14 * This file contains the low-level support and setup for the
15 * PowerPC platform, including trap and interrupt dispatch.
16 * (The PPC 8xx embedded CPUs use head_8xx.S instead.)
18 * This program is free software; you can redistribute it and/or
19 * modify it under the terms of the GNU General Public License
20 * as published by the Free Software Foundation; either version
21 * 2 of the License, or (at your option) any later version.
25 #include <linux/config.h>
29 #include <asm/pgtable.h>
30 #include <asm/cputable.h>
31 #include <asm/cache.h>
32 #include <asm/thread_info.h>
33 #include <asm/ppc_asm.h>
34 #include <asm/asm-offsets.h>
37 #include <asm/amigappc.h>
40 /* 601 only have IBAT; cr0.eq is set on 601 when using this macro */
41 #define LOAD_BAT(n, reg, RA, RB) \
42 /* see the comment for clear_bats() -- Cort */ \
44 mtspr SPRN_IBAT##n##U,RA; \
45 mtspr SPRN_DBAT##n##U,RA; \
46 lwz RA,(n*16)+0(reg); \
47 lwz RB,(n*16)+4(reg); \
48 mtspr SPRN_IBAT##n##U,RA; \
49 mtspr SPRN_IBAT##n##L,RB; \
51 lwz RA,(n*16)+8(reg); \
52 lwz RB,(n*16)+12(reg); \
53 mtspr SPRN_DBAT##n##U,RA; \
54 mtspr SPRN_DBAT##n##L,RB; \
58 .stabs "arch/powerpc/kernel/",N_SO,0,0,0f
59 .stabs "head_32.S",N_SO,0,0,0f
65 * _start is defined this way because the XCOFF loader in the OpenFirmware
66 * on the powermac expects the entry point to be a procedure descriptor.
72 * These are here for legacy reasons, the kernel used to
73 * need to look like a coff function entry for the pmac
74 * but we're always started by some kind of bootloader now.
77 nop /* used by __secondary_hold on prep (mtx) and chrp smp */
78 nop /* used by __secondary_hold on prep (mtx) and chrp smp */
82 * Enter here with the kernel text, data and bss loaded starting at
83 * 0, running with virtual == physical mapping.
84 * r5 points to the prom entry point (the client interface handler
85 * address). Address translation is turned on, with the prom
86 * managing the hash table. Interrupts are disabled. The stack
87 * pointer (r1) points to just below the end of the half-meg region
88 * from 0x380000 - 0x400000, which is mapped in already.
90 * If we are booted from MacOS via BootX, we enter with the kernel
91 * image loaded somewhere, and the following values in registers:
92 * r3: 'BooX' (0x426f6f58)
93 * r4: virtual address of boot_infos_t
98 * r4: physical address of memory base
99 * Linux/m68k style BootInfo structure at &_end.
102 * This is jumped to on prep systems right after the kernel is relocated
103 * to its proper place in memory by the boot loader. The expected layout
105 * r3: ptr to residual data
106 * r4: initrd_start or if no initrd then 0
107 * r5: initrd_end - unused if r4 is 0
108 * r6: Start of command line string
109 * r7: End of command line string
111 * This just gets a minimal mmu environment setup so we can call
112 * start_here() to do the real work.
119 * We have to do any OF calls before we map ourselves to KERNELBASE,
120 * because OF may have I/O devices mapped into that area
121 * (particularly on CHRP).
128 1: mr r31,r3 /* save parameters */
133 * early_init() does the early machine identification and does
134 * the necessary low-level setup and clears the BSS
135 * -- Cort <cort@fsmlabs.com>
140 /* On APUS the __va/__pa constants need to be set to the correct
141 * values before continuing.
145 #endif /* CONFIG_APUS */
147 /* Switch MMU off, clear BATs and flush TLB. At this point, r3 contains
148 * the physical address we are running at, returned by early_init()
158 * Call setup_cpu for CPU 0 and initialize 6xx Idle
162 bl call_setup_cpu /* Call setup_cpu for this CPU */
166 #endif /* CONFIG_6xx */
171 * We need to run with _start at physical address 0.
172 * On CHRP, we are loaded at 0x10000 since OF on CHRP uses
173 * the exception vectors at 0 (and therefore this copy
174 * overwrites OF's exception vectors with our own).
175 * The MMU is off at this point.
179 addis r4,r3,KERNELBASE@h /* current address of _start */
180 cmpwi 0,r4,0 /* are we already running at 0? */
182 #endif /* CONFIG_APUS */
184 * we now have the 1st 16M of ram mapped with the bats.
185 * prep needs the mmu to be turned on here, but pmac already has it on.
186 * this shouldn't bother the pmac since it just gets turned on again
187 * as we jump to our code at KERNELBASE. -- Cort
188 * Actually no, pmac doesn't have it on any more. BootX enters with MMU
189 * off, and in other cases, we now turn it off before changing BATs above.
193 ori r0,r0,MSR_DR|MSR_IR
196 ori r0,r0,start_here@l
199 RFI /* enables MMU */
202 * We need __secondary_hold as a place to hold the other cpus on
203 * an SMP machine, even when we are running a UP kernel.
205 . = 0xc0 /* for prep bootloader */
206 li r3,1 /* MTX only has 1 cpu */
207 .globl __secondary_hold
209 /* tell the master we're here */
210 stw r3,__secondary_hold_acknowledge@l(0)
213 /* wait until we're told to start */
216 /* our cpu # was at addr 0 - go */
217 mr r24,r3 /* cpu # */
221 #endif /* CONFIG_SMP */
223 .globl __secondary_hold_spinloop
224 __secondary_hold_spinloop:
226 .globl __secondary_hold_acknowledge
227 __secondary_hold_acknowledge:
231 * Exception entry code. This code runs with address translation
232 * turned off, i.e. using physical addresses.
233 * We assume sprg3 has the physical address of the current
234 * task's thread_struct.
236 #define EXCEPTION_PROLOG \
237 mtspr SPRN_SPRG0,r10; \
238 mtspr SPRN_SPRG1,r11; \
240 EXCEPTION_PROLOG_1; \
243 #define EXCEPTION_PROLOG_1 \
244 mfspr r11,SPRN_SRR1; /* check whether user or kernel */ \
245 andi. r11,r11,MSR_PR; \
246 tophys(r11,r1); /* use tophys(r1) if kernel */ \
248 mfspr r11,SPRN_SPRG3; \
249 lwz r11,THREAD_INFO-THREAD(r11); \
250 addi r11,r11,THREAD_SIZE; \
252 1: subi r11,r11,INT_FRAME_SIZE /* alloc exc. frame */
255 #define EXCEPTION_PROLOG_2 \
257 stw r10,_CCR(r11); /* save registers */ \
258 stw r12,GPR12(r11); \
260 mfspr r10,SPRN_SPRG0; \
261 stw r10,GPR10(r11); \
262 mfspr r12,SPRN_SPRG1; \
263 stw r12,GPR11(r11); \
265 stw r10,_LINK(r11); \
266 mfspr r12,SPRN_SRR0; \
267 mfspr r9,SPRN_SRR1; \
270 tovirt(r1,r11); /* set new kernel sp */ \
271 li r10,MSR_KERNEL & ~(MSR_IR|MSR_DR); /* can take exceptions */ \
272 MTMSRD(r10); /* (except for mach check in rtas) */ \
274 SAVE_4GPRS(3, r11); \
278 * Note: code which follows this uses cr0.eq (set if from kernel),
279 * r11, r12 (SRR0), and r9 (SRR1).
281 * Note2: once we have set r1 we are in a position to take exceptions
282 * again, and we could thus set MSR:RI at that point.
288 #define EXCEPTION(n, label, hdlr, xfer) \
292 addi r3,r1,STACK_FRAME_OVERHEAD; \
295 #define EXC_XFER_TEMPLATE(n, hdlr, trap, copyee, tfer, ret) \
297 stw r10,_TRAP(r11); \
305 #define COPY_EE(d, s) rlwimi d,s,0,16,16
308 #define EXC_XFER_STD(n, hdlr) \
309 EXC_XFER_TEMPLATE(n, hdlr, n, NOCOPY, transfer_to_handler_full, \
310 ret_from_except_full)
312 #define EXC_XFER_LITE(n, hdlr) \
313 EXC_XFER_TEMPLATE(n, hdlr, n+1, NOCOPY, transfer_to_handler, \
316 #define EXC_XFER_EE(n, hdlr) \
317 EXC_XFER_TEMPLATE(n, hdlr, n, COPY_EE, transfer_to_handler_full, \
318 ret_from_except_full)
320 #define EXC_XFER_EE_LITE(n, hdlr) \
321 EXC_XFER_TEMPLATE(n, hdlr, n+1, COPY_EE, transfer_to_handler, \
325 /* core99 pmac starts the seconary here by changing the vector, and
326 putting it back to what it was (unknown_exception) when done. */
327 #if defined(CONFIG_GEMINI) && defined(CONFIG_SMP)
329 b __secondary_start_gemini
331 EXCEPTION(0x100, Reset, unknown_exception, EXC_XFER_STD)
336 * On CHRP, this is complicated by the fact that we could get a
337 * machine check inside RTAS, and we have no guarantee that certain
338 * critical registers will have the values we expect. The set of
339 * registers that might have bad values includes all the GPRs
340 * and all the BATs. We indicate that we are in RTAS by putting
341 * a non-zero value, the address of the exception frame to use,
342 * in SPRG2. The machine check handler checks SPRG2 and uses its
343 * value if it is non-zero. If we ever needed to free up SPRG2,
344 * we could use a field in the thread_info or thread_struct instead.
345 * (Other exception handlers assume that r1 is a valid kernel stack
346 * pointer when we take an exception from supervisor mode.)
353 #ifdef CONFIG_PPC_CHRP
357 #endif /* CONFIG_PPC_CHRP */
359 7: EXCEPTION_PROLOG_2
360 addi r3,r1,STACK_FRAME_OVERHEAD
361 #ifdef CONFIG_PPC_CHRP
366 EXC_XFER_STD(0x200, machine_check_exception)
367 #ifdef CONFIG_PPC_CHRP
368 1: b machine_check_in_rtas
371 /* Data access exception. */
376 andis. r0,r10,0xa470 /* weird error? */
377 bne 1f /* if not, try to put a PTE */
378 mfspr r4,SPRN_DAR /* into the hash table */
379 rlwinm r3,r10,32-15,21,21 /* DSISR_STORE -> _PAGE_RW */
381 1: stw r10,_DSISR(r11)
384 EXC_XFER_EE_LITE(0x300, handle_page_fault)
387 /* Instruction access exception. */
391 andis. r0,r9,0x4000 /* no pte found? */
392 beq 1f /* if so, try to put a PTE */
393 li r3,0 /* into the hash table */
394 mr r4,r12 /* SRR0 is fault address */
398 EXC_XFER_EE_LITE(0x400, handle_page_fault)
400 /* External interrupt */
401 EXCEPTION(0x500, HardwareInterrupt, do_IRQ, EXC_XFER_LITE)
403 /* Alignment exception */
411 addi r3,r1,STACK_FRAME_OVERHEAD
412 EXC_XFER_EE(0x600, alignment_exception)
414 /* Program check exception */
415 EXCEPTION(0x700, ProgramCheck, program_check_exception, EXC_XFER_STD)
417 /* Floating-point unavailable */
421 bne load_up_fpu /* if from user, just load it up */
422 addi r3,r1,STACK_FRAME_OVERHEAD
423 EXC_XFER_EE_LITE(0x800, kernel_fp_unavailable_exception)
426 EXCEPTION(0x900, Decrementer, timer_interrupt, EXC_XFER_LITE)
428 EXCEPTION(0xa00, Trap_0a, unknown_exception, EXC_XFER_EE)
429 EXCEPTION(0xb00, Trap_0b, unknown_exception, EXC_XFER_EE)
435 EXC_XFER_EE_LITE(0xc00, DoSyscall)
437 /* Single step - not used on 601 */
438 EXCEPTION(0xd00, SingleStep, single_step_exception, EXC_XFER_STD)
439 EXCEPTION(0xe00, Trap_0e, unknown_exception, EXC_XFER_EE)
442 * The Altivec unavailable trap is at 0x0f20. Foo.
443 * We effectively remap it to 0x3000.
444 * We include an altivec unavailable exception vector even if
445 * not configured for Altivec, so that you can't panic a
446 * non-altivec kernel running on a machine with altivec just
447 * by executing an altivec instruction.
457 addi r3,r1,STACK_FRAME_OVERHEAD
458 EXC_XFER_EE(0xf00, unknown_exception)
461 * Handle TLB miss for instruction on 603/603e.
462 * Note: we get an alternate set of r0 - r3 to use automatically.
468 * r1: linux style pte ( later becomes ppc hardware pte )
469 * r2: ptr to linux-style pte
473 /* Get PTE (linux-style) and check access */
475 lis r1,KERNELBASE@h /* check if kernel address */
478 li r1,_PAGE_USER|_PAGE_PRESENT /* low addresses tested as user */
481 lis r2,swapper_pg_dir@ha /* if kernel address, use */
482 addi r2,r2,swapper_pg_dir@l /* kernel page table */
483 mfspr r1,SPRN_SRR1 /* and MSR_PR bit from SRR1 */
484 rlwinm r1,r1,32-12,29,29 /* shift MSR_PR to _PAGE_USER posn */
486 rlwimi r2,r3,12,20,29 /* insert top 10 bits of address */
487 lwz r2,0(r2) /* get pmd entry */
488 rlwinm. r2,r2,0,0,19 /* extract address of pte page */
489 beq- InstructionAddressInvalid /* return if no mapping */
490 rlwimi r2,r3,22,20,29 /* insert next 10 bits of address */
491 lwz r3,0(r2) /* get linux-style pte */
492 andc. r1,r1,r3 /* check access & ~permission */
493 bne- InstructionAddressInvalid /* return if access not permitted */
494 ori r3,r3,_PAGE_ACCESSED /* set _PAGE_ACCESSED in pte */
496 * NOTE! We are assuming this is not an SMP system, otherwise
497 * we would need to update the pte atomically with lwarx/stwcx.
499 stw r3,0(r2) /* update PTE (accessed bit) */
500 /* Convert linux-style PTE to low word of PPC-style PTE */
501 rlwinm r1,r3,32-10,31,31 /* _PAGE_RW -> PP lsb */
502 rlwinm r2,r3,32-7,31,31 /* _PAGE_DIRTY -> PP lsb */
503 and r1,r1,r2 /* writable if _RW and _DIRTY */
504 rlwimi r3,r3,32-1,30,30 /* _PAGE_USER -> PP msb */
505 rlwimi r3,r3,32-1,31,31 /* _PAGE_USER -> PP lsb */
506 ori r1,r1,0xe14 /* clear out reserved bits and M */
507 andc r1,r3,r1 /* PP = user? (rw&dirty? 2: 3): 0 */
511 mfspr r3,SPRN_SRR1 /* Need to restore CR0 */
514 InstructionAddressInvalid:
516 rlwinm r1,r3,9,6,6 /* Get load/store bit */
519 mtspr SPRN_DSISR,r1 /* (shouldn't be needed) */
520 mtctr r0 /* Restore CTR */
521 andi. r2,r3,0xFFFF /* Clear upper bits of SRR1 */
524 mfspr r1,SPRN_IMISS /* Get failing address */
525 rlwinm. r2,r2,0,31,31 /* Check for little endian access */
526 rlwimi r2,r2,1,30,30 /* change 1 -> 3 */
528 mtspr SPRN_DAR,r1 /* Set fault address */
529 mfmsr r0 /* Restore "normal" registers */
530 xoris r0,r0,MSR_TGPR>>16
531 mtcrf 0x80,r3 /* Restore CR0 */
536 * Handle TLB miss for DATA Load operation on 603/603e
542 * r1: linux style pte ( later becomes ppc hardware pte )
543 * r2: ptr to linux-style pte
547 /* Get PTE (linux-style) and check access */
549 lis r1,KERNELBASE@h /* check if kernel address */
552 li r1,_PAGE_USER|_PAGE_PRESENT /* low addresses tested as user */
555 lis r2,swapper_pg_dir@ha /* if kernel address, use */
556 addi r2,r2,swapper_pg_dir@l /* kernel page table */
557 mfspr r1,SPRN_SRR1 /* and MSR_PR bit from SRR1 */
558 rlwinm r1,r1,32-12,29,29 /* shift MSR_PR to _PAGE_USER posn */
560 rlwimi r2,r3,12,20,29 /* insert top 10 bits of address */
561 lwz r2,0(r2) /* get pmd entry */
562 rlwinm. r2,r2,0,0,19 /* extract address of pte page */
563 beq- DataAddressInvalid /* return if no mapping */
564 rlwimi r2,r3,22,20,29 /* insert next 10 bits of address */
565 lwz r3,0(r2) /* get linux-style pte */
566 andc. r1,r1,r3 /* check access & ~permission */
567 bne- DataAddressInvalid /* return if access not permitted */
568 ori r3,r3,_PAGE_ACCESSED /* set _PAGE_ACCESSED in pte */
570 * NOTE! We are assuming this is not an SMP system, otherwise
571 * we would need to update the pte atomically with lwarx/stwcx.
573 stw r3,0(r2) /* update PTE (accessed bit) */
574 /* Convert linux-style PTE to low word of PPC-style PTE */
575 rlwinm r1,r3,32-10,31,31 /* _PAGE_RW -> PP lsb */
576 rlwinm r2,r3,32-7,31,31 /* _PAGE_DIRTY -> PP lsb */
577 and r1,r1,r2 /* writable if _RW and _DIRTY */
578 rlwimi r3,r3,32-1,30,30 /* _PAGE_USER -> PP msb */
579 rlwimi r3,r3,32-1,31,31 /* _PAGE_USER -> PP lsb */
580 ori r1,r1,0xe14 /* clear out reserved bits and M */
581 andc r1,r3,r1 /* PP = user? (rw&dirty? 2: 3): 0 */
585 mfspr r3,SPRN_SRR1 /* Need to restore CR0 */
590 rlwinm r1,r3,9,6,6 /* Get load/store bit */
593 mtctr r0 /* Restore CTR */
594 andi. r2,r3,0xFFFF /* Clear upper bits of SRR1 */
596 mfspr r1,SPRN_DMISS /* Get failing address */
597 rlwinm. r2,r2,0,31,31 /* Check for little endian access */
598 beq 20f /* Jump if big endian */
600 20: mtspr SPRN_DAR,r1 /* Set fault address */
601 mfmsr r0 /* Restore "normal" registers */
602 xoris r0,r0,MSR_TGPR>>16
603 mtcrf 0x80,r3 /* Restore CR0 */
608 * Handle TLB miss for DATA Store on 603/603e
614 * r1: linux style pte ( later becomes ppc hardware pte )
615 * r2: ptr to linux-style pte
619 /* Get PTE (linux-style) and check access */
621 lis r1,KERNELBASE@h /* check if kernel address */
624 li r1,_PAGE_RW|_PAGE_USER|_PAGE_PRESENT /* access flags */
627 lis r2,swapper_pg_dir@ha /* if kernel address, use */
628 addi r2,r2,swapper_pg_dir@l /* kernel page table */
629 mfspr r1,SPRN_SRR1 /* and MSR_PR bit from SRR1 */
630 rlwinm r1,r1,32-12,29,29 /* shift MSR_PR to _PAGE_USER posn */
632 rlwimi r2,r3,12,20,29 /* insert top 10 bits of address */
633 lwz r2,0(r2) /* get pmd entry */
634 rlwinm. r2,r2,0,0,19 /* extract address of pte page */
635 beq- DataAddressInvalid /* return if no mapping */
636 rlwimi r2,r3,22,20,29 /* insert next 10 bits of address */
637 lwz r3,0(r2) /* get linux-style pte */
638 andc. r1,r1,r3 /* check access & ~permission */
639 bne- DataAddressInvalid /* return if access not permitted */
640 ori r3,r3,_PAGE_ACCESSED|_PAGE_DIRTY
642 * NOTE! We are assuming this is not an SMP system, otherwise
643 * we would need to update the pte atomically with lwarx/stwcx.
645 stw r3,0(r2) /* update PTE (accessed/dirty bits) */
646 /* Convert linux-style PTE to low word of PPC-style PTE */
647 rlwimi r3,r3,32-1,30,30 /* _PAGE_USER -> PP msb */
648 li r1,0xe15 /* clear out reserved bits and M */
649 andc r1,r3,r1 /* PP = user? 2: 0 */
653 mfspr r3,SPRN_SRR1 /* Need to restore CR0 */
657 #ifndef CONFIG_ALTIVEC
658 #define altivec_assist_exception unknown_exception
661 EXCEPTION(0x1300, Trap_13, instruction_breakpoint_exception, EXC_XFER_EE)
662 EXCEPTION(0x1400, SMI, SMIException, EXC_XFER_EE)
663 EXCEPTION(0x1500, Trap_15, unknown_exception, EXC_XFER_EE)
664 EXCEPTION(0x1600, Trap_16, altivec_assist_exception, EXC_XFER_EE)
665 EXCEPTION(0x1700, Trap_17, TAUException, EXC_XFER_STD)
666 EXCEPTION(0x1800, Trap_18, unknown_exception, EXC_XFER_EE)
667 EXCEPTION(0x1900, Trap_19, unknown_exception, EXC_XFER_EE)
668 EXCEPTION(0x1a00, Trap_1a, unknown_exception, EXC_XFER_EE)
669 EXCEPTION(0x1b00, Trap_1b, unknown_exception, EXC_XFER_EE)
670 EXCEPTION(0x1c00, Trap_1c, unknown_exception, EXC_XFER_EE)
671 EXCEPTION(0x1d00, Trap_1d, unknown_exception, EXC_XFER_EE)
672 EXCEPTION(0x1e00, Trap_1e, unknown_exception, EXC_XFER_EE)
673 EXCEPTION(0x1f00, Trap_1f, unknown_exception, EXC_XFER_EE)
674 EXCEPTION(0x2000, RunMode, RunModeException, EXC_XFER_EE)
675 EXCEPTION(0x2100, Trap_21, unknown_exception, EXC_XFER_EE)
676 EXCEPTION(0x2200, Trap_22, unknown_exception, EXC_XFER_EE)
677 EXCEPTION(0x2300, Trap_23, unknown_exception, EXC_XFER_EE)
678 EXCEPTION(0x2400, Trap_24, unknown_exception, EXC_XFER_EE)
679 EXCEPTION(0x2500, Trap_25, unknown_exception, EXC_XFER_EE)
680 EXCEPTION(0x2600, Trap_26, unknown_exception, EXC_XFER_EE)
681 EXCEPTION(0x2700, Trap_27, unknown_exception, EXC_XFER_EE)
682 EXCEPTION(0x2800, Trap_28, unknown_exception, EXC_XFER_EE)
683 EXCEPTION(0x2900, Trap_29, unknown_exception, EXC_XFER_EE)
684 EXCEPTION(0x2a00, Trap_2a, unknown_exception, EXC_XFER_EE)
685 EXCEPTION(0x2b00, Trap_2b, unknown_exception, EXC_XFER_EE)
686 EXCEPTION(0x2c00, Trap_2c, unknown_exception, EXC_XFER_EE)
687 EXCEPTION(0x2d00, Trap_2d, unknown_exception, EXC_XFER_EE)
688 EXCEPTION(0x2e00, Trap_2e, unknown_exception, EXC_XFER_EE)
689 EXCEPTION(0x2f00, MOLTrampoline, unknown_exception, EXC_XFER_EE_LITE)
691 .globl mol_trampoline
692 .set mol_trampoline, i0x2f00
698 #ifdef CONFIG_ALTIVEC
699 bne load_up_altivec /* if from user, just load it up */
700 #endif /* CONFIG_ALTIVEC */
701 EXC_XFER_EE_LITE(0xf20, altivec_unavailable_exception)
703 #ifdef CONFIG_ALTIVEC
704 /* Note that the AltiVec support is closely modeled after the FP
705 * support. Changes to one are likely to be applicable to the
709 * Disable AltiVec for the task which had AltiVec previously,
710 * and save its AltiVec registers in its thread_struct.
711 * Enables AltiVec for use in the kernel on return.
712 * On SMP we know the AltiVec units are free, since we give it up every
717 MTMSRD(r5) /* enable use of AltiVec now */
720 * For SMP, we don't do lazy AltiVec switching because it just gets too
721 * horrendously complex, especially when a task switches from one CPU
722 * to another. Instead we call giveup_altivec in switch_to.
726 addis r3,r6,last_task_used_altivec@ha
727 lwz r4,last_task_used_altivec@l(r3)
731 addi r4,r4,THREAD /* want THREAD of last_task_used_altivec */
738 lwz r4,_MSR-STACK_FRAME_OVERHEAD(r5)
740 andc r4,r4,r10 /* disable altivec for previous task */
741 stw r4,_MSR-STACK_FRAME_OVERHEAD(r5)
743 #endif /* CONFIG_SMP */
744 /* enable use of AltiVec after return */
746 mfspr r5,SPRN_SPRG3 /* current task's THREAD (phys) */
749 stw r4,THREAD_USED_VR(r5)
756 stw r4,last_task_used_altivec@l(r3)
757 #endif /* CONFIG_SMP */
758 /* restore registers and return */
759 /* we haven't used ctr or xer or lr */
760 b fast_exception_return
763 * AltiVec unavailable trap from kernel - print a message, but let
764 * the task use AltiVec in the kernel until it returns to user mode.
769 stw r3,_MSR(r1) /* enable use of AltiVec after return */
772 mr r4,r2 /* current */
776 87: .string "AltiVec used in kernel (task=%p, pc=%x) \n"
780 * giveup_altivec(tsk)
781 * Disable AltiVec for the task given as the argument,
782 * and save the AltiVec registers in its thread_struct.
783 * Enables AltiVec for use in the kernel on return.
786 .globl giveup_altivec
791 MTMSRD(r5) /* enable use of AltiVec now */
794 beqlr- /* if no previous owner, done */
795 addi r3,r3,THREAD /* want THREAD of task */
798 SAVE_32VRS(0, r4, r3)
803 lwz r4,_MSR-STACK_FRAME_OVERHEAD(r5)
805 andc r4,r4,r3 /* disable AltiVec for previous task */
806 stw r4,_MSR-STACK_FRAME_OVERHEAD(r5)
810 lis r4,last_task_used_altivec@ha
811 stw r5,last_task_used_altivec@l(r4)
812 #endif /* CONFIG_SMP */
814 #endif /* CONFIG_ALTIVEC */
817 * This code is jumped to from the startup code to copy
818 * the kernel image to physical address 0.
821 addis r9,r26,klimit@ha /* fetch klimit */
823 addis r25,r25,-KERNELBASE@h
824 li r3,0 /* Destination base address */
825 li r6,0 /* Destination offset */
826 li r5,0x4000 /* # bytes of memory to copy */
827 bl copy_and_flush /* copy the first 0x4000 bytes */
828 addi r0,r3,4f@l /* jump to the address of 4f */
829 mtctr r0 /* in copy and do the rest. */
830 bctr /* jump to the copy */
832 bl copy_and_flush /* copy the rest */
836 * Copy routine used to copy the kernel to start at physical address 0
837 * and flush and invalidate the caches as needed.
838 * r3 = dest addr, r4 = source addr, r5 = copy limit, r6 = start offset
839 * on exit, r3, r4, r5 are unchanged, r6 is updated to be >= r5.
841 _GLOBAL(copy_and_flush)
844 4: li r0,L1_CACHE_BYTES/4
846 3: addi r6,r6,4 /* copy a cache line */
850 dcbst r6,r3 /* write it to memory */
852 icbi r6,r3 /* flush the icache line */
855 sync /* additional sync needed on g4 */
863 * On APUS the physical base address of the kernel is not known at compile
864 * time, which means the __pa/__va constants used are incorrect. In the
865 * __init section is recorded the virtual addresses of instructions using
866 * these constants, so all that has to be done is fix these before
867 * continuing the kernel boot.
869 * r4 = The physical address of the kernel base.
873 addis r10,r10,-KERNELBASE@h /* virt_to_phys constant */
874 neg r11,r10 /* phys_to_virt constant */
876 lis r12,__vtop_table_begin@h
877 ori r12,r12,__vtop_table_begin@l
878 add r12,r12,r10 /* table begin phys address */
879 lis r13,__vtop_table_end@h
880 ori r13,r13,__vtop_table_end@l
881 add r13,r13,r10 /* table end phys address */
884 1: lwzu r14,4(r12) /* virt address of instruction */
885 add r14,r14,r10 /* phys address of instruction */
886 lwz r15,0(r14) /* instruction, now insert top */
887 rlwimi r15,r10,16,16,31 /* half of vp const in low half */
888 stw r15,0(r14) /* of instruction and restore. */
889 dcbst r0,r14 /* write it to memory */
891 icbi r0,r14 /* flush the icache line */
894 sync /* additional sync needed on g4 */
898 * Map the memory where the exception handlers will
899 * be copied to when hash constants have been patched.
901 #ifdef CONFIG_APUS_FAST_EXCEPT
906 ori r8,r8,0x2 /* 128KB, supervisor */
910 lis r12,__ptov_table_begin@h
911 ori r12,r12,__ptov_table_begin@l
912 add r12,r12,r10 /* table begin phys address */
913 lis r13,__ptov_table_end@h
914 ori r13,r13,__ptov_table_end@l
915 add r13,r13,r10 /* table end phys address */
918 1: lwzu r14,4(r12) /* virt address of instruction */
919 add r14,r14,r10 /* phys address of instruction */
920 lwz r15,0(r14) /* instruction, now insert top */
921 rlwimi r15,r11,16,16,31 /* half of pv const in low half*/
922 stw r15,0(r14) /* of instruction and restore. */
923 dcbst r0,r14 /* write it to memory */
925 icbi r0,r14 /* flush the icache line */
929 sync /* additional sync needed on g4 */
930 isync /* No speculative loading until now */
933 /***********************************************************************
934 * Please note that on APUS the exception handlers are located at the
935 * physical address 0xfff0000. For this reason, the exception handlers
936 * cannot use relative branches to access the code below.
937 ***********************************************************************/
938 #endif /* CONFIG_APUS */
942 .globl __secondary_start_gemini
943 __secondary_start_gemini:
952 #endif /* CONFIG_GEMINI */
954 .globl __secondary_start_pmac_0
955 __secondary_start_pmac_0:
956 /* NB the entries for cpus 0, 1, 2 must each occupy 8 bytes. */
965 /* on powersurge, we come in here with IR=0 and DR=1, and DBAT 0
966 set to map the 0xf0000000 - 0xffffffff region */
968 rlwinm r0,r0,0,28,26 /* clear DR (0x10) */
973 .globl __secondary_start
975 /* Copy some CPU settings from CPU 0 */
976 bl __restore_cpu_setup
980 bl call_setup_cpu /* Call setup_cpu for this CPU */
984 #endif /* CONFIG_6xx */
986 /* get current_thread_info and current */
987 lis r1,secondary_ti@ha
989 lwz r1,secondary_ti@l(r1)
994 addi r1,r1,THREAD_SIZE-STACK_FRAME_OVERHEAD
999 /* load up the MMU */
1002 /* ptr to phys current thread */
1004 addi r4,r4,THREAD /* phys address of our thread_struct */
1008 mtspr SPRN_SPRG2,r3 /* 0 => not in RTAS */
1010 /* enable MMU and jump to start_secondary */
1013 lis r3,start_secondary@h
1014 ori r3,r3,start_secondary@l
1019 #endif /* CONFIG_SMP */
1022 * Those generic dummy functions are kept for CPUs not
1023 * included in CONFIG_6xx
1025 #if !defined(CONFIG_6xx)
1026 _GLOBAL(__save_cpu_setup)
1028 _GLOBAL(__restore_cpu_setup)
1030 #endif /* !defined(CONFIG_6xx) */
1034 * Load stuff into the MMU. Intended to be called with
1038 sync /* Force all PTE updates to finish */
1040 tlbia /* Clear all TLB entries */
1041 sync /* wait for tlbia/tlbie to finish */
1042 TLBSYNC /* ... on all CPUs */
1043 /* Load the SDR1 register (hash table base & size) */
1048 li r0,16 /* load up segment register values */
1049 mtctr r0 /* for context 0 */
1050 lis r3,0x2000 /* Ku = 1, VSID = 0 */
1053 addi r3,r3,0x111 /* increment VSID */
1054 addis r4,r4,0x1000 /* address of next segment */
1057 /* Load the BAT registers with the values set up by MMU_init.
1058 MMU_init takes care of whether we're on a 601 or not. */
1065 LOAD_BAT(0,r3,r4,r5)
1066 LOAD_BAT(1,r3,r4,r5)
1067 LOAD_BAT(2,r3,r4,r5)
1068 LOAD_BAT(3,r3,r4,r5)
1073 * This is where the main kernel code starts.
1076 /* ptr to current */
1078 ori r2,r2,init_task@l
1079 /* Set up for using our exception vectors */
1080 /* ptr to phys current thread */
1082 addi r4,r4,THREAD /* init task's THREAD */
1086 mtspr SPRN_SPRG2,r3 /* 0 => not in RTAS */
1089 lis r1,init_thread_union@ha
1090 addi r1,r1,init_thread_union@l
1092 stwu r0,THREAD_SIZE-STACK_FRAME_OVERHEAD(r1)
1094 * Do early platform-specific initialization,
1095 * and set up the MMU.
1103 /* Copy exception code to exception vector base on APUS. */
1105 #ifdef CONFIG_APUS_FAST_EXCEPT
1106 lis r3,0xfff0 /* Copy to 0xfff00000 */
1108 lis r3,0 /* Copy to 0x00000000 */
1110 li r5,0x4000 /* # bytes of memory to copy */
1112 bl copy_and_flush /* copy the first 0x4000 bytes */
1113 #endif /* CONFIG_APUS */
1116 * Go back to running unmapped so we can load up new values
1117 * for SDR1 (hash table pointer) and the segment registers
1118 * and change to using our exception vectors.
1123 li r3,MSR_KERNEL & ~(MSR_IR|MSR_DR)
1129 /* Load up the kernel context */
1132 #ifdef CONFIG_BDI_SWITCH
1133 /* Add helper information for the Abatron bdiGDB debugger.
1134 * We do this here because we know the mmu is disabled, and
1135 * will be enabled for real in just a few instructions.
1137 lis r5, abatron_pteptrs@h
1138 ori r5, r5, abatron_pteptrs@l
1139 stw r5, 0xf0(r0) /* This much match your Abatron config */
1140 lis r6, swapper_pg_dir@h
1141 ori r6, r6, swapper_pg_dir@l
1144 #endif /* CONFIG_BDI_SWITCH */
1146 /* Now turn on the MMU for real! */
1149 lis r3,start_kernel@h
1150 ori r3,r3,start_kernel@l
1157 * Set up the segment registers for a new context.
1159 _GLOBAL(set_context)
1160 mulli r3,r3,897 /* multiply context by skew factor */
1161 rlwinm r3,r3,4,8,27 /* VSID = (context & 0xfffff) << 4 */
1162 addis r3,r3,0x6000 /* Set Ks, Ku bits */
1163 li r0,NUM_USER_SEGMENTS
1166 #ifdef CONFIG_BDI_SWITCH
1167 /* Context switch the PTE pointer for the Abatron BDI2000.
1168 * The PGDIR is passed as second argument.
1170 lis r5, KERNELBASE@h
1178 addi r3,r3,0x111 /* next VSID */
1179 rlwinm r3,r3,0,8,3 /* clear out any overflow from VSID field */
1180 addis r4,r4,0x1000 /* address of next segment */
1187 * An undocumented "feature" of 604e requires that the v bit
1188 * be cleared before changing BAT values.
1190 * Also, newer IBM firmware does not clear bat3 and 4 so
1191 * this makes sure it's done.
1197 rlwinm r9,r9,16,16,31 /* r9 = 1 for 601, 4 for 604 */
1201 mtspr SPRN_DBAT0U,r10
1202 mtspr SPRN_DBAT0L,r10
1203 mtspr SPRN_DBAT1U,r10
1204 mtspr SPRN_DBAT1L,r10
1205 mtspr SPRN_DBAT2U,r10
1206 mtspr SPRN_DBAT2L,r10
1207 mtspr SPRN_DBAT3U,r10
1208 mtspr SPRN_DBAT3L,r10
1210 mtspr SPRN_IBAT0U,r10
1211 mtspr SPRN_IBAT0L,r10
1212 mtspr SPRN_IBAT1U,r10
1213 mtspr SPRN_IBAT1L,r10
1214 mtspr SPRN_IBAT2U,r10
1215 mtspr SPRN_IBAT2L,r10
1216 mtspr SPRN_IBAT3U,r10
1217 mtspr SPRN_IBAT3L,r10
1219 /* Here's a tweak: at this point, CPU setup have
1220 * not been called yet, so HIGH_BAT_EN may not be
1221 * set in HID0 for the 745x processors. However, it
1222 * seems that doesn't affect our ability to actually
1223 * write to these SPRs.
1225 mtspr SPRN_DBAT4U,r10
1226 mtspr SPRN_DBAT4L,r10
1227 mtspr SPRN_DBAT5U,r10
1228 mtspr SPRN_DBAT5L,r10
1229 mtspr SPRN_DBAT6U,r10
1230 mtspr SPRN_DBAT6L,r10
1231 mtspr SPRN_DBAT7U,r10
1232 mtspr SPRN_DBAT7L,r10
1233 mtspr SPRN_IBAT4U,r10
1234 mtspr SPRN_IBAT4L,r10
1235 mtspr SPRN_IBAT5U,r10
1236 mtspr SPRN_IBAT5L,r10
1237 mtspr SPRN_IBAT6U,r10
1238 mtspr SPRN_IBAT6L,r10
1239 mtspr SPRN_IBAT7U,r10
1240 mtspr SPRN_IBAT7L,r10
1241 END_FTR_SECTION_IFSET(CPU_FTR_HAS_HIGH_BATS)
1246 1: addic. r10, r10, -0x1000
1253 addi r4, r3, __after_mmu_off - _start
1255 andi. r0,r3,MSR_DR|MSR_IR /* MMU enabled? */
1264 * Use the first pair of BAT registers to map the 1st 16MB
1265 * of RAM to KERNELBASE. From this point on we can't safely
1269 lis r11,KERNELBASE@h
1271 rlwinm r9,r9,16,16,31 /* r9 = 1 for 601, 4 for 604 */
1274 ori r11,r11,4 /* set up BAT registers for 601 */
1275 li r8,0x7f /* valid, block length = 8MB */
1276 oris r9,r11,0x800000@h /* set up BAT reg for 2nd 8M */
1277 oris r10,r8,0x800000@h /* set up BAT reg for 2nd 8M */
1278 mtspr SPRN_IBAT0U,r11 /* N.B. 601 has valid bit in */
1279 mtspr SPRN_IBAT0L,r8 /* lower BAT register */
1280 mtspr SPRN_IBAT1U,r9
1281 mtspr SPRN_IBAT1L,r10
1287 ori r8,r8,0x12 /* R/W access, M=1 */
1289 ori r8,r8,2 /* R/W access */
1290 #endif /* CONFIG_SMP */
1292 ori r11,r11,BL_8M<<2|0x2 /* set up 8MB BAT registers for 604 */
1294 ori r11,r11,BL_256M<<2|0x2 /* set up BAT registers for 604 */
1295 #endif /* CONFIG_APUS */
1297 mtspr SPRN_DBAT0L,r8 /* N.B. 6xx (not 601) have valid */
1298 mtspr SPRN_DBAT0U,r11 /* bit in upper BAT register */
1299 mtspr SPRN_IBAT0L,r8
1300 mtspr SPRN_IBAT0U,r11
1306 /* Jump into the system reset for the rom.
1307 * We first disable the MMU, and then jump to the ROM reset address.
1309 * r3 is the board info structure, r4 is the location for starting.
1310 * I use this for building a small kernel that can load other kernels,
1311 * rather than trying to write or rely on a rom monitor that can tftp load.
1316 rlwinm r0,r0,0,17,15 /* clear MSR_EE in r0 */
1320 mfspr r11, SPRN_HID0
1322 ori r10,r10,HID0_ICE|HID0_DCE
1324 mtspr SPRN_HID0, r11
1326 li r5, MSR_ME|MSR_RI
1328 addis r6,r6,-KERNELBASE@h
1342 * We put a few things here that have to be page-aligned.
1343 * This stuff goes at the beginning of the data segment,
1344 * which is page-aligned.
1349 .globl empty_zero_page
1353 .globl swapper_pg_dir
1358 * This space gets a copy of optional info passed to us by the bootstrap
1359 * Used to pass parameters into the kernel like root=/dev/sda1, etc.
1365 .globl intercept_table
1367 .long 0, 0, i0x200, i0x300, i0x400, 0, i0x600, i0x700
1368 .long i0x800, 0, 0, 0, 0, i0xd00, 0, 0
1369 .long 0, 0, 0, i0x1300, 0, 0, 0, 0
1370 .long 0, 0, 0, 0, 0, 0, 0, 0
1371 .long 0, 0, 0, 0, 0, 0, 0, 0
1372 .long 0, 0, 0, 0, 0, 0, 0, 0
1374 /* Room for two PTE pointers, usually the kernel and current user pointers
1375 * to their respective root page table.