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.
12 * Adapted for 64bit PowerPC by Dave Engebretsen, Peter Bergner, and
13 * Mike Corrigan {engebret|bergner|mikejc}@us.ibm.com
15 * This file contains the entry point for the 64-bit kernel along
16 * with some early initialization code common to all 64-bit powerpc
19 * This program is free software; you can redistribute it and/or
20 * modify it under the terms of the GNU General Public License
21 * as published by the Free Software Foundation; either version
22 * 2 of the License, or (at your option) any later version.
25 #include <linux/threads.h>
29 #include <asm/ppc_asm.h>
30 #include <asm/asm-offsets.h>
32 #include <asm/cputable.h>
33 #include <asm/setup.h>
34 #include <asm/hvcall.h>
35 #include <asm/iseries/lpar_map.h>
36 #include <asm/thread_info.h>
37 #include <asm/firmware.h>
38 #include <asm/page_64.h>
39 #include <asm/irqflags.h>
41 /* The physical memory is layed out such that the secondary processor
42 * spin code sits at 0x0000...0x00ff. On server, the vectors follow
43 * using the layout described in exceptions-64s.S
47 * Entering into this code we make the following assumptions:
49 * For pSeries or server processors:
50 * 1. The MMU is off & open firmware is running in real mode.
51 * 2. The kernel is entered at __start
54 * 1. The MMU is on (as it always is for iSeries)
55 * 2. The kernel is entered at system_reset_iSeries
57 * For Book3E processors:
58 * 1. The MMU is on running in AS0 in a state defined in ePAPR
59 * 2. The kernel is entered at __start
66 /* NOP this out unconditionally */
68 b .__start_initialization_multiplatform
71 /* Catch branch to 0 in real mode */
74 /* Secondary processors spin on this value until it becomes nonzero.
75 * When it does it contains the real address of the descriptor
76 * of the function that the cpu should jump to to continue
79 .globl __secondary_hold_spinloop
80 __secondary_hold_spinloop:
83 /* Secondary processors write this value with their cpu # */
84 /* after they enter the spin loop immediately below. */
85 .globl __secondary_hold_acknowledge
86 __secondary_hold_acknowledge:
89 #ifdef CONFIG_PPC_ISERIES
91 * At offset 0x20, there is a pointer to iSeries LPAR data.
92 * This is required by the hypervisor
95 .llong hvReleaseData-KERNELBASE
96 #endif /* CONFIG_PPC_ISERIES */
98 #ifdef CONFIG_CRASH_DUMP
99 /* This flag is set to 1 by a loader if the kernel should run
100 * at the loaded address instead of the linked address. This
101 * is used by kexec-tools to keep the the kdump kernel in the
102 * crash_kernel region. The loader is responsible for
103 * observing the alignment requirement.
105 /* Do not move this variable as kexec-tools knows about it. */
109 .long 0x72756e30 /* "run0" -- relocate to 0 by default */
114 * The following code is used to hold secondary processors
115 * in a spin loop after they have entered the kernel, but
116 * before the bulk of the kernel has been relocated. This code
117 * is relocated to physical address 0x60 before prom_init is run.
118 * All of it must fit below the first exception vector at 0x100.
119 * Use .globl here not _GLOBAL because we want __secondary_hold
120 * to be the actual text address, not a descriptor.
122 .globl __secondary_hold
124 #ifndef CONFIG_PPC_BOOK3E
127 mtmsrd r24 /* RI on */
129 /* Grab our physical cpu number */
132 /* Tell the master cpu we're here */
133 /* Relocation is off & we are located at an address less */
134 /* than 0x100, so only need to grab low order offset. */
135 std r24,__secondary_hold_acknowledge-_stext(0)
138 /* All secondary cpus wait here until told to start. */
139 100: ld r4,__secondary_hold_spinloop-_stext(0)
143 #if defined(CONFIG_SMP) || defined(CONFIG_KEXEC)
144 ld r4,0(r4) /* deref function descriptor */
153 /* This value is used to mark exception frames on the stack. */
156 .tc ID_72656773_68657265[TC],0x7265677368657265
160 * On server, we include the exception vectors code here as it
161 * relies on absolute addressing which is only possible within
162 * this compilation unit
164 #ifdef CONFIG_PPC_BOOK3S
165 #include "exceptions-64s.S"
168 _GLOBAL(generic_secondary_thread_init)
171 /* turn on 64-bit mode */
174 /* get a valid TOC pointer, wherever we're mapped at */
177 #ifdef CONFIG_PPC_BOOK3E
178 /* Book3E initialization */
180 bl .book3e_secondary_thread_init
182 b generic_secondary_common_init
185 * On pSeries and most other platforms, secondary processors spin
186 * in the following code.
187 * At entry, r3 = this processor's number (physical cpu id)
189 * On Book3E, r4 = 1 to indicate that the initial TLB entry for
190 * this core already exists (setup via some other mechanism such
191 * as SCOM before entry).
193 _GLOBAL(generic_secondary_smp_init)
197 /* turn on 64-bit mode */
200 /* get a valid TOC pointer, wherever we're mapped at */
203 #ifdef CONFIG_PPC_BOOK3E
204 /* Book3E initialization */
207 bl .book3e_secondary_core_init
210 generic_secondary_common_init:
211 /* Set up a paca value for this processor. Since we have the
212 * physical cpu id in r24, we need to search the pacas to find
213 * which logical id maps to our physical one.
215 LOAD_REG_ADDR(r13, paca) /* Get base vaddr of paca array */
216 li r5,0 /* logical cpu id */
217 1: lhz r6,PACAHWCPUID(r13) /* Load HW procid from paca */
218 cmpw r6,r24 /* Compare to our id */
220 addi r13,r13,PACA_SIZE /* Loop to next PACA on miss */
225 mr r3,r24 /* not found, copy phys to r3 */
226 b .kexec_wait /* next kernel might do better */
228 2: mtspr SPRN_SPRG_PACA,r13 /* Save vaddr of paca in an SPRG */
229 #ifdef CONFIG_PPC_BOOK3E
230 addi r12,r13,PACA_EXTLB /* and TLB exc frame in another */
231 mtspr SPRN_SPRG_TLB_EXFRAME,r12
234 /* From now on, r24 is expected to be logical cpuid */
237 lbz r23,PACAPROCSTART(r13) /* Test if this processor should */
241 b 3b /* Never go on non-SMP */
244 beq 3b /* Loop until told to go */
246 sync /* order paca.run and cur_cpu_spec */
248 /* See if we need to call a cpu state restore handler */
249 LOAD_REG_ADDR(r23, cur_cpu_spec)
251 ld r23,CPU_SPEC_RESTORE(r23)
258 4: /* Create a temp kernel stack for use before relocation is on. */
259 ld r1,PACAEMERGSP(r13)
260 subi r1,r1,STACK_FRAME_OVERHEAD
267 * Assumes we're mapped EA == RA if the MMU is on.
269 #ifdef CONFIG_PPC_BOOK3S
272 andi. r0,r3,MSR_IR|MSR_DR
280 b . /* prevent speculative execution */
285 * Here is our main kernel entry point. We support currently 2 kind of entries
286 * depending on the value of r5.
288 * r5 != NULL -> OF entry, we go to prom_init, "legacy" parameter content
291 * r5 == NULL -> kexec style entry. r3 is a physical pointer to the
292 * DT block, r4 is a physical pointer to the kernel itself
295 _GLOBAL(__start_initialization_multiplatform)
296 /* Make sure we are running in 64 bits mode */
299 /* Get TOC pointer (current runtime address) */
302 /* find out where we are now */
304 0: mflr r26 /* r26 = runtime addr here */
305 addis r26,r26,(_stext - 0b)@ha
306 addi r26,r26,(_stext - 0b)@l /* current runtime base addr */
309 * Are we booted from a PROM Of-type client-interface ?
313 b .__boot_from_prom /* yes -> prom */
315 /* Save parameters */
319 #ifdef CONFIG_PPC_BOOK3E
320 bl .start_initialization_book3e
321 b .__after_prom_start
323 /* Setup some critical 970 SPRs before switching MMU off */
326 cmpwi r0,0x39 /* 970 */
328 cmpwi r0,0x3c /* 970FX */
330 cmpwi r0,0x44 /* 970MP */
332 cmpwi r0,0x45 /* 970GX */
334 1: bl .__cpu_preinit_ppc970
337 /* Switch off MMU if not already off */
339 b .__after_prom_start
340 #endif /* CONFIG_PPC_BOOK3E */
342 _INIT_STATIC(__boot_from_prom)
343 #ifdef CONFIG_PPC_OF_BOOT_TRAMPOLINE
344 /* Save parameters */
352 * Align the stack to 16-byte boundary
353 * Depending on the size and layout of the ELF sections in the initial
354 * boot binary, the stack pointer may be unaligned on PowerMac
358 #ifdef CONFIG_RELOCATABLE
359 /* Relocate code for where we are now */
364 /* Restore parameters */
371 /* Do all of the interaction with OF client interface */
374 #endif /* #CONFIG_PPC_OF_BOOT_TRAMPOLINE */
376 /* We never return. We also hit that trap if trying to boot
377 * from OF while CONFIG_PPC_OF_BOOT_TRAMPOLINE isn't selected */
380 _STATIC(__after_prom_start)
381 #ifdef CONFIG_RELOCATABLE
382 /* process relocations for the final address of the kernel */
383 lis r25,PAGE_OFFSET@highest /* compute virtual base of kernel */
385 #ifdef CONFIG_CRASH_DUMP
386 lwz r7,__run_at_load-_stext(r26)
387 cmplwi cr0,r7,1 /* kdump kernel ? - stay where we are */
396 * We need to run with _stext at physical address PHYSICAL_START.
397 * This will leave some code in the first 256B of
398 * real memory, which are reserved for software use.
400 * Note: This process overwrites the OF exception vectors.
402 li r3,0 /* target addr */
403 #ifdef CONFIG_PPC_BOOK3E
404 tovirt(r3,r3) /* on booke, we already run at PAGE_OFFSET */
406 mr. r4,r26 /* In some cases the loader may */
407 beq 9f /* have already put us at zero */
408 li r6,0x100 /* Start offset, the first 0x100 */
409 /* bytes were copied earlier. */
410 #ifdef CONFIG_PPC_BOOK3E
411 tovirt(r6,r6) /* on booke, we already run at PAGE_OFFSET */
414 #ifdef CONFIG_CRASH_DUMP
416 * Check if the kernel has to be running as relocatable kernel based on the
417 * variable __run_at_load, if it is set the kernel is treated as relocatable
418 * kernel, otherwise it will be moved to PHYSICAL_START
420 lwz r7,__run_at_load-_stext(r26)
424 li r5,__end_interrupts - _stext /* just copy interrupts */
428 lis r5,(copy_to_here - _stext)@ha
429 addi r5,r5,(copy_to_here - _stext)@l /* # bytes of memory to copy */
431 bl .copy_and_flush /* copy the first n bytes */
432 /* this includes the code being */
434 addis r8,r3,(4f - _stext)@ha /* Jump to the copy of this code */
435 addi r8,r8,(4f - _stext)@l /* that we just made */
439 p_end: .llong _end - _stext
441 4: /* Now copy the rest of the kernel up to _end */
442 addis r5,r26,(p_end - _stext)@ha
443 ld r5,(p_end - _stext)@l(r5) /* get _end */
444 5: bl .copy_and_flush /* copy the rest */
446 9: b .start_here_multiplatform
449 * Copy routine used to copy the kernel to start at physical address 0
450 * and flush and invalidate the caches as needed.
451 * r3 = dest addr, r4 = source addr, r5 = copy limit, r6 = start offset
452 * on exit, r3, r4, r5 are unchanged, r6 is updated to be >= r5.
454 * Note: this routine *only* clobbers r0, r6 and lr
456 _GLOBAL(copy_and_flush)
459 4: li r0,8 /* Use the smallest common */
460 /* denominator cache line */
461 /* size. This results in */
462 /* extra cache line flushes */
463 /* but operation is correct. */
464 /* Can't get cache line size */
465 /* from NACA as it is being */
468 mtctr r0 /* put # words/line in ctr */
469 3: addi r6,r6,8 /* copy a cache line */
473 dcbst r6,r3 /* write it to memory */
475 icbi r6,r3 /* flush the icache line */
487 #ifdef CONFIG_PPC_PMAC
489 * On PowerMac, secondary processors starts from the reset vector, which
490 * is temporarily turned into a call to one of the functions below.
495 .globl __secondary_start_pmac_0
496 __secondary_start_pmac_0:
497 /* NB the entries for cpus 0, 1, 2 must each occupy 8 bytes. */
507 _GLOBAL(pmac_secondary_start)
508 /* turn on 64-bit mode */
513 rldimi r3,r0,40,23 /* clear bit 23 (rm_ci) */
520 /* get TOC pointer (real address) */
523 /* Copy some CPU settings from CPU 0 */
524 bl .__restore_cpu_ppc970
526 /* pSeries do that early though I don't think we really need it */
529 mtmsrd r3 /* RI on */
531 /* Set up a paca value for this processor. */
532 LOAD_REG_ADDR(r4,paca) /* Get base vaddr of paca array */
533 mulli r13,r24,PACA_SIZE /* Calculate vaddr of right paca */
534 add r13,r13,r4 /* for this processor. */
535 mtspr SPRN_SPRG_PACA,r13 /* Save vaddr of paca in an SPRG*/
537 /* Create a temp kernel stack for use before relocation is on. */
538 ld r1,PACAEMERGSP(r13)
539 subi r1,r1,STACK_FRAME_OVERHEAD
543 #endif /* CONFIG_PPC_PMAC */
546 * This function is called after the master CPU has released the
547 * secondary processors. The execution environment is relocation off.
548 * The paca for this processor has the following fields initialized at
550 * 1. Processor number
551 * 2. Segment table pointer (virtual address)
552 * On entry the following are set:
553 * r1 = stack pointer. vaddr for iSeries, raddr (temp stack) for pSeries
554 * r24 = cpu# (in Linux terms)
555 * r13 = paca virtual address
556 * SPRG_PACA = paca virtual address
561 .globl __secondary_start
563 /* Set thread priority to MEDIUM */
566 /* Do early setup for that CPU (stab, slb, hash table pointer) */
567 bl .early_setup_secondary
569 /* Initialize the kernel stack. Just a repeat for iSeries. */
570 LOAD_REG_ADDR(r3, current_set)
571 sldi r28,r24,3 /* get current_set[cpu#] */
573 addi r1,r1,THREAD_SIZE-STACK_FRAME_OVERHEAD
574 std r1,PACAKSAVE(r13)
576 /* Clear backchain so we get nice backtraces */
580 /* enable MMU and jump to start_secondary */
581 LOAD_REG_ADDR(r3, .start_secondary_prolog)
582 LOAD_REG_IMMEDIATE(r4, MSR_KERNEL)
583 #ifdef CONFIG_PPC_ISERIES
587 stb r8,PACAHARDIRQEN(r13)
588 END_FW_FTR_SECTION_IFSET(FW_FEATURE_ISERIES)
591 stb r7,PACAHARDIRQEN(r13)
592 END_FW_FTR_SECTION_IFCLR(FW_FEATURE_ISERIES)
593 stb r7,PACASOFTIRQEN(r13)
598 b . /* prevent speculative execution */
601 * Running with relocation on at this point. All we want to do is
602 * zero the stack back-chain pointer and get the TOC virtual address
603 * before going into C code.
605 _GLOBAL(start_secondary_prolog)
608 std r3,0(r1) /* Zero the stack frame pointer */
614 * This subroutine clobbers r11 and r12
616 _GLOBAL(enable_64b_mode)
617 mfmsr r11 /* grab the current MSR */
618 #ifdef CONFIG_PPC_BOOK3E
619 oris r11,r11,0x8000 /* CM bit set, we'll set ICM later */
621 #else /* CONFIG_PPC_BOOK3E */
622 li r12,(MSR_SF | MSR_ISF)@highest
631 * This puts the TOC pointer into r2, offset by 0x8000 (as expected
632 * by the toolchain). It computes the correct value for wherever we
633 * are running at the moment, using position-independent code.
635 _GLOBAL(relative_toc)
639 ld r2,(p_toc - 0b)(r9)
644 p_toc: .llong __toc_start + 0x8000 - 0b
647 * This is where the main kernel code starts.
649 _INIT_STATIC(start_here_multiplatform)
650 /* set up the TOC (real address) */
653 /* Clear out the BSS. It may have been done in prom_init,
654 * already but that's irrelevant since prom_init will soon
655 * be detached from the kernel completely. Besides, we need
656 * to clear it now for kexec-style entry.
658 LOAD_REG_ADDR(r11,__bss_stop)
659 LOAD_REG_ADDR(r8,__bss_start)
660 sub r11,r11,r8 /* bss size */
661 addi r11,r11,7 /* round up to an even double word */
662 srdi. r11,r11,3 /* shift right by 3 */
666 mtctr r11 /* zero this many doublewords */
671 #ifndef CONFIG_PPC_BOOK3E
674 mtmsrd r6 /* RI on */
677 #ifdef CONFIG_RELOCATABLE
678 /* Save the physical address we're running at in kernstart_addr */
679 LOAD_REG_ADDR(r4, kernstart_addr)
684 /* The following gets the stack set up with the regs */
685 /* pointing to the real addr of the kernel stack. This is */
686 /* all done to support the C function call below which sets */
687 /* up the htab. This is done because we have relocated the */
688 /* kernel but are still running in real mode. */
690 LOAD_REG_ADDR(r3,init_thread_union)
692 /* set up a stack pointer */
693 addi r1,r3,THREAD_SIZE
695 stdu r0,-STACK_FRAME_OVERHEAD(r1)
697 /* Do very early kernel initializations, including initial hash table,
698 * stab and slb setup before we turn on relocation. */
700 /* Restore parameters passed from prom_init/kexec */
702 bl .early_setup /* also sets r13 and SPRG_PACA */
704 LOAD_REG_ADDR(r3, .start_here_common)
709 b . /* prevent speculative execution */
711 /* This is where all platforms converge execution */
712 _INIT_GLOBAL(start_here_common)
713 /* relocation is on at this point */
714 std r1,PACAKSAVE(r13)
716 /* Load the TOC (virtual address) */
721 /* Load up the kernel context */
724 stb r5,PACASOFTIRQEN(r13) /* Soft Disabled */
725 #ifdef CONFIG_PPC_ISERIES
728 ori r5,r5,MSR_EE /* Hard Enabled on iSeries*/
731 END_FW_FTR_SECTION_IFSET(FW_FEATURE_ISERIES)
733 stb r5,PACAHARDIRQEN(r13) /* Hard Disabled on others */
741 * We put a few things here that have to be page-aligned.
742 * This stuff goes at the beginning of the bss, which is page-aligned.
748 .globl empty_zero_page
752 .globl swapper_pg_dir
754 .space PGD_TABLE_SIZE