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
126 mtmsrd r24 /* RI on */
128 /* Grab our physical cpu number */
131 /* Tell the master cpu we're here */
132 /* Relocation is off & we are located at an address less */
133 /* than 0x100, so only need to grab low order offset. */
134 std r24,__secondary_hold_acknowledge-_stext(0)
137 /* All secondary cpus wait here until told to start. */
138 100: ld r4,__secondary_hold_spinloop-_stext(0)
142 #if defined(CONFIG_SMP) || defined(CONFIG_KEXEC)
143 ld r4,0(r4) /* deref function descriptor */
151 /* This value is used to mark exception frames on the stack. */
154 .tc ID_72656773_68657265[TC],0x7265677368657265
158 * On server, we include the exception vectors code here as it
159 * relies on absolute addressing which is only possible within
160 * this compilation unit
162 #ifdef CONFIG_PPC_BOOK3S
163 #include "exceptions-64s.S"
168 * On pSeries and most other platforms, secondary processors spin
169 * in the following code.
170 * At entry, r3 = this processor's number (physical cpu id)
172 _GLOBAL(generic_secondary_smp_init)
175 /* turn on 64-bit mode */
178 /* get the TOC pointer (real address) */
181 /* Set up a paca value for this processor. Since we have the
182 * physical cpu id in r24, we need to search the pacas to find
183 * which logical id maps to our physical one.
185 LOAD_REG_ADDR(r13, paca) /* Get base vaddr of paca array */
186 li r5,0 /* logical cpu id */
187 1: lhz r6,PACAHWCPUID(r13) /* Load HW procid from paca */
188 cmpw r6,r24 /* Compare to our id */
190 addi r13,r13,PACA_SIZE /* Loop to next PACA on miss */
195 mr r3,r24 /* not found, copy phys to r3 */
196 b .kexec_wait /* next kernel might do better */
198 2: mtspr SPRN_SPRG_PACA,r13 /* Save vaddr of paca in an SPRG */
199 /* From now on, r24 is expected to be logical cpuid */
202 lbz r23,PACAPROCSTART(r13) /* Test if this processor should */
206 b 3b /* Never go on non-SMP */
209 beq 3b /* Loop until told to go */
211 sync /* order paca.run and cur_cpu_spec */
213 /* See if we need to call a cpu state restore handler */
214 LOAD_REG_ADDR(r23, cur_cpu_spec)
216 ld r23,CPU_SPEC_RESTORE(r23)
223 4: /* Create a temp kernel stack for use before relocation is on. */
224 ld r1,PACAEMERGSP(r13)
225 subi r1,r1,STACK_FRAME_OVERHEAD
232 * Assumes we're mapped EA == RA if the MMU is on.
236 andi. r0,r3,MSR_IR|MSR_DR
244 b . /* prevent speculative execution */
248 * Here is our main kernel entry point. We support currently 2 kind of entries
249 * depending on the value of r5.
251 * r5 != NULL -> OF entry, we go to prom_init, "legacy" parameter content
254 * r5 == NULL -> kexec style entry. r3 is a physical pointer to the
255 * DT block, r4 is a physical pointer to the kernel itself
258 _GLOBAL(__start_initialization_multiplatform)
259 /* Make sure we are running in 64 bits mode */
262 /* Get TOC pointer (current runtime address) */
265 /* find out where we are now */
267 0: mflr r26 /* r26 = runtime addr here */
268 addis r26,r26,(_stext - 0b)@ha
269 addi r26,r26,(_stext - 0b)@l /* current runtime base addr */
272 * Are we booted from a PROM Of-type client-interface ?
276 b .__boot_from_prom /* yes -> prom */
278 /* Save parameters */
282 /* Setup some critical 970 SPRs before switching MMU off */
285 cmpwi r0,0x39 /* 970 */
287 cmpwi r0,0x3c /* 970FX */
289 cmpwi r0,0x44 /* 970MP */
291 cmpwi r0,0x45 /* 970GX */
293 1: bl .__cpu_preinit_ppc970
296 /* Switch off MMU if not already off */
298 b .__after_prom_start
300 _INIT_STATIC(__boot_from_prom)
301 #ifdef CONFIG_PPC_OF_BOOT_TRAMPOLINE
302 /* Save parameters */
310 * Align the stack to 16-byte boundary
311 * Depending on the size and layout of the ELF sections in the initial
312 * boot binary, the stack pointer may be unaligned on PowerMac
316 #ifdef CONFIG_RELOCATABLE
317 /* Relocate code for where we are now */
322 /* Restore parameters */
329 /* Do all of the interaction with OF client interface */
332 #endif /* #CONFIG_PPC_OF_BOOT_TRAMPOLINE */
334 /* We never return. We also hit that trap if trying to boot
335 * from OF while CONFIG_PPC_OF_BOOT_TRAMPOLINE isn't selected */
338 _STATIC(__after_prom_start)
339 #ifdef CONFIG_RELOCATABLE
340 /* process relocations for the final address of the kernel */
341 lis r25,PAGE_OFFSET@highest /* compute virtual base of kernel */
343 #ifdef CONFIG_CRASH_DUMP
344 lwz r7,__run_at_load-_stext(r26)
345 cmplwi cr0,r7,1 /* kdump kernel ? - stay where we are */
354 * We need to run with _stext at physical address PHYSICAL_START.
355 * This will leave some code in the first 256B of
356 * real memory, which are reserved for software use.
358 * Note: This process overwrites the OF exception vectors.
360 li r3,0 /* target addr */
361 mr. r4,r26 /* In some cases the loader may */
362 beq 9f /* have already put us at zero */
363 li r6,0x100 /* Start offset, the first 0x100 */
364 /* bytes were copied earlier. */
366 #ifdef CONFIG_CRASH_DUMP
368 * Check if the kernel has to be running as relocatable kernel based on the
369 * variable __run_at_load, if it is set the kernel is treated as relocatable
370 * kernel, otherwise it will be moved to PHYSICAL_START
372 lwz r7,__run_at_load-_stext(r26)
376 li r5,__end_interrupts - _stext /* just copy interrupts */
380 lis r5,(copy_to_here - _stext)@ha
381 addi r5,r5,(copy_to_here - _stext)@l /* # bytes of memory to copy */
383 bl .copy_and_flush /* copy the first n bytes */
384 /* this includes the code being */
386 addis r8,r3,(4f - _stext)@ha /* Jump to the copy of this code */
387 addi r8,r8,(4f - _stext)@l /* that we just made */
391 p_end: .llong _end - _stext
393 4: /* Now copy the rest of the kernel up to _end */
394 addis r5,r26,(p_end - _stext)@ha
395 ld r5,(p_end - _stext)@l(r5) /* get _end */
396 5: bl .copy_and_flush /* copy the rest */
398 9: b .start_here_multiplatform
401 * Copy routine used to copy the kernel to start at physical address 0
402 * and flush and invalidate the caches as needed.
403 * r3 = dest addr, r4 = source addr, r5 = copy limit, r6 = start offset
404 * on exit, r3, r4, r5 are unchanged, r6 is updated to be >= r5.
406 * Note: this routine *only* clobbers r0, r6 and lr
408 _GLOBAL(copy_and_flush)
411 4: li r0,8 /* Use the smallest common */
412 /* denominator cache line */
413 /* size. This results in */
414 /* extra cache line flushes */
415 /* but operation is correct. */
416 /* Can't get cache line size */
417 /* from NACA as it is being */
420 mtctr r0 /* put # words/line in ctr */
421 3: addi r6,r6,8 /* copy a cache line */
425 dcbst r6,r3 /* write it to memory */
427 icbi r6,r3 /* flush the icache line */
439 #ifdef CONFIG_PPC_PMAC
441 * On PowerMac, secondary processors starts from the reset vector, which
442 * is temporarily turned into a call to one of the functions below.
447 .globl __secondary_start_pmac_0
448 __secondary_start_pmac_0:
449 /* NB the entries for cpus 0, 1, 2 must each occupy 8 bytes. */
459 _GLOBAL(pmac_secondary_start)
460 /* turn on 64-bit mode */
465 rldimi r3,r0,40,23 /* clear bit 23 (rm_ci) */
472 /* get TOC pointer (real address) */
475 /* Copy some CPU settings from CPU 0 */
476 bl .__restore_cpu_ppc970
478 /* pSeries do that early though I don't think we really need it */
481 mtmsrd r3 /* RI on */
483 /* Set up a paca value for this processor. */
484 LOAD_REG_ADDR(r4,paca) /* Get base vaddr of paca array */
485 mulli r13,r24,PACA_SIZE /* Calculate vaddr of right paca */
486 add r13,r13,r4 /* for this processor. */
487 mtspr SPRN_SPRG_PACA,r13 /* Save vaddr of paca in an SPRG*/
489 /* Create a temp kernel stack for use before relocation is on. */
490 ld r1,PACAEMERGSP(r13)
491 subi r1,r1,STACK_FRAME_OVERHEAD
495 #endif /* CONFIG_PPC_PMAC */
498 * This function is called after the master CPU has released the
499 * secondary processors. The execution environment is relocation off.
500 * The paca for this processor has the following fields initialized at
502 * 1. Processor number
503 * 2. Segment table pointer (virtual address)
504 * On entry the following are set:
505 * r1 = stack pointer. vaddr for iSeries, raddr (temp stack) for pSeries
506 * r24 = cpu# (in Linux terms)
507 * r13 = paca virtual address
508 * SPRG_PACA = paca virtual address
510 .globl __secondary_start
512 /* Set thread priority to MEDIUM */
515 /* Do early setup for that CPU (stab, slb, hash table pointer) */
516 bl .early_setup_secondary
518 /* Initialize the kernel stack. Just a repeat for iSeries. */
519 LOAD_REG_ADDR(r3, current_set)
520 sldi r28,r24,3 /* get current_set[cpu#] */
522 addi r1,r1,THREAD_SIZE-STACK_FRAME_OVERHEAD
523 std r1,PACAKSAVE(r13)
525 /* Clear backchain so we get nice backtraces */
529 /* enable MMU and jump to start_secondary */
530 LOAD_REG_ADDR(r3, .start_secondary_prolog)
531 LOAD_REG_IMMEDIATE(r4, MSR_KERNEL)
532 #ifdef CONFIG_PPC_ISERIES
536 stb r8,PACAHARDIRQEN(r13)
537 END_FW_FTR_SECTION_IFSET(FW_FEATURE_ISERIES)
540 stb r7,PACAHARDIRQEN(r13)
541 END_FW_FTR_SECTION_IFCLR(FW_FEATURE_ISERIES)
542 stb r7,PACASOFTIRQEN(r13)
547 b . /* prevent speculative execution */
550 * Running with relocation on at this point. All we want to do is
551 * zero the stack back-chain pointer and get the TOC virtual address
552 * before going into C code.
554 _GLOBAL(start_secondary_prolog)
557 std r3,0(r1) /* Zero the stack frame pointer */
563 * This subroutine clobbers r11 and r12
565 _GLOBAL(enable_64b_mode)
566 mfmsr r11 /* grab the current MSR */
567 li r12,(MSR_SF | MSR_ISF)@highest
575 * This puts the TOC pointer into r2, offset by 0x8000 (as expected
576 * by the toolchain). It computes the correct value for wherever we
577 * are running at the moment, using position-independent code.
579 _GLOBAL(relative_toc)
583 ld r2,(p_toc - 0b)(r9)
588 p_toc: .llong __toc_start + 0x8000 - 0b
591 * This is where the main kernel code starts.
593 _INIT_STATIC(start_here_multiplatform)
594 /* set up the TOC (real address) */
597 /* Clear out the BSS. It may have been done in prom_init,
598 * already but that's irrelevant since prom_init will soon
599 * be detached from the kernel completely. Besides, we need
600 * to clear it now for kexec-style entry.
602 LOAD_REG_ADDR(r11,__bss_stop)
603 LOAD_REG_ADDR(r8,__bss_start)
604 sub r11,r11,r8 /* bss size */
605 addi r11,r11,7 /* round up to an even double word */
606 srdi. r11,r11,3 /* shift right by 3 */
610 mtctr r11 /* zero this many doublewords */
617 mtmsrd r6 /* RI on */
619 #ifdef CONFIG_RELOCATABLE
620 /* Save the physical address we're running at in kernstart_addr */
621 LOAD_REG_ADDR(r4, kernstart_addr)
626 /* The following gets the stack set up with the regs */
627 /* pointing to the real addr of the kernel stack. This is */
628 /* all done to support the C function call below which sets */
629 /* up the htab. This is done because we have relocated the */
630 /* kernel but are still running in real mode. */
632 LOAD_REG_ADDR(r3,init_thread_union)
634 /* set up a stack pointer */
635 addi r1,r3,THREAD_SIZE
637 stdu r0,-STACK_FRAME_OVERHEAD(r1)
639 /* Do very early kernel initializations, including initial hash table,
640 * stab and slb setup before we turn on relocation. */
642 /* Restore parameters passed from prom_init/kexec */
644 bl .early_setup /* also sets r13 and SPRG_PACA */
646 LOAD_REG_ADDR(r3, .start_here_common)
651 b . /* prevent speculative execution */
653 /* This is where all platforms converge execution */
654 _INIT_GLOBAL(start_here_common)
655 /* relocation is on at this point */
656 std r1,PACAKSAVE(r13)
658 /* Load the TOC (virtual address) */
663 /* Load up the kernel context */
666 stb r5,PACASOFTIRQEN(r13) /* Soft Disabled */
667 #ifdef CONFIG_PPC_ISERIES
670 ori r5,r5,MSR_EE /* Hard Enabled on iSeries*/
673 END_FW_FTR_SECTION_IFSET(FW_FEATURE_ISERIES)
675 stb r5,PACAHARDIRQEN(r13) /* Hard Disabled on others */
683 * We put a few things here that have to be page-aligned.
684 * This stuff goes at the beginning of the bss, which is page-aligned.
690 .globl empty_zero_page
694 .globl swapper_pg_dir
696 .space PGD_TABLE_SIZE