xref: /openbmc/linux/arch/powerpc/kernel/head_85xx.S (revision 046b212a) 
1/* SPDX-License-Identifier: GPL-2.0-or-later */
2/*
3 * Kernel execution entry point code.
4 *
5 *    Copyright (c) 1995-1996 Gary Thomas <gdt@linuxppc.org>
6 *	Initial PowerPC version.
7 *    Copyright (c) 1996 Cort Dougan <cort@cs.nmt.edu>
8 *	Rewritten for PReP
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 2002-2004 MontaVista Software, Inc.
24 *	PowerPC 44x support, Matt Porter <mporter@kernel.crashing.org>
25 *    Copyright 2004 Freescale Semiconductor, Inc
26 *	PowerPC e500 modifications, Kumar Gala <galak@kernel.crashing.org>
27 */
28
29#include <linux/init.h>
30#include <linux/threads.h>
31#include <linux/pgtable.h>
32#include <linux/linkage.h>
33
34#include <asm/processor.h>
35#include <asm/page.h>
36#include <asm/mmu.h>
37#include <asm/cputable.h>
38#include <asm/thread_info.h>
39#include <asm/ppc_asm.h>
40#include <asm/asm-offsets.h>
41#include <asm/cache.h>
42#include <asm/ptrace.h>
43#include <asm/feature-fixups.h>
44#include "head_booke.h"
45
46/* As with the other PowerPC ports, it is expected that when code
47 * execution begins here, the following registers contain valid, yet
48 * optional, information:
49 *
50 *   r3 - Board info structure pointer (DRAM, frequency, MAC address, etc.)
51 *   r4 - Starting address of the init RAM disk
52 *   r5 - Ending address of the init RAM disk
53 *   r6 - Start of kernel command line string (e.g. "mem=128")
54 *   r7 - End of kernel command line string
55 *
56 */
57	__HEAD
58_GLOBAL(_stext);
59_GLOBAL(_start);
60	/*
61	 * Reserve a word at a fixed location to store the address
62	 * of abatron_pteptrs
63	 */
64	nop
65
66	/* Translate device tree address to physical, save in r30/r31 */
67	bl	get_phys_addr
68	mr	r30,r3
69	mr	r31,r4
70
71	li	r25,0			/* phys kernel start (low) */
72	li	r24,0			/* CPU number */
73	li	r23,0			/* phys kernel start (high) */
74
75#ifdef CONFIG_RELOCATABLE
76	LOAD_REG_ADDR_PIC(r3, _stext)	/* Get our current runtime base */
77
78	/* Translate _stext address to physical, save in r23/r25 */
79	bl	get_phys_addr
80	mr	r23,r3
81	mr	r25,r4
82
83	bcl	20,31,$+4
840:	mflr	r8
85	addis	r3,r8,(is_second_reloc - 0b)@ha
86	lwz	r19,(is_second_reloc - 0b)@l(r3)
87
88	/* Check if this is the second relocation. */
89	cmpwi	r19,1
90	bne	1f
91
92	/*
93	 * For the second relocation, we already get the real memstart_addr
94	 * from device tree. So we will map PAGE_OFFSET to memstart_addr,
95	 * then the virtual address of start kernel should be:
96	 *          PAGE_OFFSET + (kernstart_addr - memstart_addr)
97	 * Since the offset between kernstart_addr and memstart_addr should
98	 * never be beyond 1G, so we can just use the lower 32bit of them
99	 * for the calculation.
100	 */
101	lis	r3,PAGE_OFFSET@h
102
103	addis	r4,r8,(kernstart_addr - 0b)@ha
104	addi	r4,r4,(kernstart_addr - 0b)@l
105	lwz	r5,4(r4)
106
107	addis	r6,r8,(memstart_addr - 0b)@ha
108	addi	r6,r6,(memstart_addr - 0b)@l
109	lwz	r7,4(r6)
110
111	subf	r5,r7,r5
112	add	r3,r3,r5
113	b	2f
114
1151:
116	/*
117	 * We have the runtime (virtual) address of our base.
118	 * We calculate our shift of offset from a 64M page.
119	 * We could map the 64M page we belong to at PAGE_OFFSET and
120	 * get going from there.
121	 */
122	lis	r4,KERNELBASE@h
123	ori	r4,r4,KERNELBASE@l
124	rlwinm	r6,r25,0,0x3ffffff		/* r6 = PHYS_START % 64M */
125	rlwinm	r5,r4,0,0x3ffffff		/* r5 = KERNELBASE % 64M */
126	subf	r3,r5,r6			/* r3 = r6 - r5 */
127	add	r3,r4,r3			/* Required Virtual Address */
128
1292:	bl	relocate
130
131	/*
132	 * For the second relocation, we already set the right tlb entries
133	 * for the kernel space, so skip the code in 85xx_entry_mapping.S
134	*/
135	cmpwi	r19,1
136	beq	set_ivor
137#endif
138
139/* We try to not make any assumptions about how the boot loader
140 * setup or used the TLBs.  We invalidate all mappings from the
141 * boot loader and load a single entry in TLB1[0] to map the
142 * first 64M of kernel memory.  Any boot info passed from the
143 * bootloader needs to live in this first 64M.
144 *
145 * Requirement on bootloader:
146 *  - The page we're executing in needs to reside in TLB1 and
147 *    have IPROT=1.  If not an invalidate broadcast could
148 *    evict the entry we're currently executing in.
149 *
150 *  r3 = Index of TLB1 were executing in
151 *  r4 = Current MSR[IS]
152 *  r5 = Index of TLB1 temp mapping
153 *
154 * Later in mapin_ram we will correctly map lowmem, and resize TLB1[0]
155 * if needed
156 */
157
158_GLOBAL(__early_start)
159	LOAD_REG_ADDR_PIC(r20, kernstart_virt_addr)
160	lwz     r20,0(r20)
161
162#define ENTRY_MAPPING_BOOT_SETUP
163#include "85xx_entry_mapping.S"
164#undef ENTRY_MAPPING_BOOT_SETUP
165
166set_ivor:
167	/* Establish the interrupt vector offsets */
168	SET_IVOR(0,  CriticalInput);
169	SET_IVOR(1,  MachineCheck);
170	SET_IVOR(2,  DataStorage);
171	SET_IVOR(3,  InstructionStorage);
172	SET_IVOR(4,  ExternalInput);
173	SET_IVOR(5,  Alignment);
174	SET_IVOR(6,  Program);
175	SET_IVOR(7,  FloatingPointUnavailable);
176	SET_IVOR(8,  SystemCall);
177	SET_IVOR(9,  AuxillaryProcessorUnavailable);
178	SET_IVOR(10, Decrementer);
179	SET_IVOR(11, FixedIntervalTimer);
180	SET_IVOR(12, WatchdogTimer);
181	SET_IVOR(13, DataTLBError);
182	SET_IVOR(14, InstructionTLBError);
183	SET_IVOR(15, DebugCrit);
184
185	/* Establish the interrupt vector base */
186	lis	r4,interrupt_base@h	/* IVPR only uses the high 16-bits */
187	mtspr	SPRN_IVPR,r4
188
189	/* Setup the defaults for TLB entries */
190	li	r2,(MAS4_TSIZED(BOOK3E_PAGESZ_4K))@l
191	mtspr	SPRN_MAS4, r2
192
193#if !defined(CONFIG_BDI_SWITCH)
194	/*
195	 * The Abatron BDI JTAG debugger does not tolerate others
196	 * mucking with the debug registers.
197	 */
198	lis	r2,DBCR0_IDM@h
199	mtspr	SPRN_DBCR0,r2
200	isync
201	/* clear any residual debug events */
202	li	r2,-1
203	mtspr	SPRN_DBSR,r2
204#endif
205
206#ifdef CONFIG_SMP
207	/* Check to see if we're the second processor, and jump
208	 * to the secondary_start code if so
209	 */
210	LOAD_REG_ADDR_PIC(r24, boot_cpuid)
211	lwz	r24, 0(r24)
212	cmpwi	r24, -1
213	mfspr   r24,SPRN_PIR
214	bne	__secondary_start
215#endif
216
217	/*
218	 * This is where the main kernel code starts.
219	 */
220
221	/* ptr to current */
222	lis	r2,init_task@h
223	ori	r2,r2,init_task@l
224
225	/* ptr to current thread */
226	addi	r4,r2,THREAD	/* init task's THREAD */
227	mtspr	SPRN_SPRG_THREAD,r4
228
229	/* stack */
230	lis	r1,init_thread_union@h
231	ori	r1,r1,init_thread_union@l
232	li	r0,0
233	stwu	r0,THREAD_SIZE-STACK_FRAME_MIN_SIZE(r1)
234
235#ifdef CONFIG_SMP
236	stw	r24, TASK_CPU(r2)
237#endif
238
239	bl	early_init
240
241#ifdef CONFIG_KASAN
242	bl	kasan_early_init
243#endif
244#ifdef CONFIG_RELOCATABLE
245	mr	r3,r30
246	mr	r4,r31
247#ifdef CONFIG_PHYS_64BIT
248	mr	r5,r23
249	mr	r6,r25
250#else
251	mr	r5,r25
252#endif
253	bl	relocate_init
254#endif
255
256#ifdef CONFIG_DYNAMIC_MEMSTART
257	lis	r3,kernstart_addr@ha
258	la	r3,kernstart_addr@l(r3)
259#ifdef CONFIG_PHYS_64BIT
260	stw	r23,0(r3)
261	stw	r25,4(r3)
262#else
263	stw	r25,0(r3)
264#endif
265#endif
266
267/*
268 * Decide what sort of machine this is and initialize the MMU.
269 */
270	mr	r3,r30
271	mr	r4,r31
272	bl	machine_init
273	bl	MMU_init
274
275	/* Setup PTE pointers for the Abatron bdiGDB */
276	lis	r6, swapper_pg_dir@h
277	ori	r6, r6, swapper_pg_dir@l
278	lis	r5, abatron_pteptrs@h
279	ori	r5, r5, abatron_pteptrs@l
280	lis     r3, kernstart_virt_addr@ha
281	lwz     r4, kernstart_virt_addr@l(r3)
282	stw	r5, 0(r4)	/* Save abatron_pteptrs at a fixed location */
283	stw	r6, 0(r5)
284
285	/* Let's move on */
286	lis	r4,start_kernel@h
287	ori	r4,r4,start_kernel@l
288	lis	r3,MSR_KERNEL@h
289	ori	r3,r3,MSR_KERNEL@l
290	mtspr	SPRN_SRR0,r4
291	mtspr	SPRN_SRR1,r3
292	rfi			/* change context and jump to start_kernel */
293
294/* Macros to hide the PTE size differences
295 *
296 * FIND_PTE -- walks the page tables given EA & pgdir pointer
297 *   r10 -- EA of fault
298 *   r11 -- PGDIR pointer
299 *   r12 -- free
300 *   label 2: is the bailout case
301 *
302 * if we find the pte (fall through):
303 *   r11 is low pte word
304 *   r12 is pointer to the pte
305 *   r10 is the pshift from the PGD, if we're a hugepage
306 */
307#ifdef CONFIG_PTE_64BIT
308#ifdef CONFIG_HUGETLB_PAGE
309#define FIND_PTE	\
310	rlwinm	r12, r10, 13, 19, 29;	/* Compute pgdir/pmd offset */	\
311	lwzx	r11, r12, r11;		/* Get pgd/pmd entry */		\
312	rlwinm.	r12, r11, 0, 0, 20;	/* Extract pt base address */	\
313	blt	1000f;			/* Normal non-huge page */	\
314	beq	2f;			/* Bail if no table */		\
315	oris	r11, r11, PD_HUGE@h;	/* Put back address bit */	\
316	andi.	r10, r11, HUGEPD_SHIFT_MASK@l; /* extract size field */	\
317	xor	r12, r10, r11;		/* drop size bits from pointer */ \
318	b	1001f;							\
3191000:	rlwimi	r12, r10, 23, 20, 28;	/* Compute pte address */	\
320	li	r10, 0;			/* clear r10 */			\
3211001:	lwz	r11, 4(r12);		/* Get pte entry */
322#else
323#define FIND_PTE	\
324	rlwinm	r12, r10, 13, 19, 29;	/* Compute pgdir/pmd offset */	\
325	lwzx	r11, r12, r11;		/* Get pgd/pmd entry */		\
326	rlwinm.	r12, r11, 0, 0, 20;	/* Extract pt base address */	\
327	beq	2f;			/* Bail if no table */		\
328	rlwimi	r12, r10, 23, 20, 28;	/* Compute pte address */	\
329	lwz	r11, 4(r12);		/* Get pte entry */
330#endif /* HUGEPAGE */
331#else /* !PTE_64BIT */
332#define FIND_PTE	\
333	rlwimi	r11, r10, 12, 20, 29;	/* Create L1 (pgdir/pmd) address */	\
334	lwz	r11, 0(r11);		/* Get L1 entry */			\
335	rlwinm.	r12, r11, 0, 0, 19;	/* Extract L2 (pte) base address */	\
336	beq	2f;			/* Bail if no table */			\
337	rlwimi	r12, r10, 22, 20, 29;	/* Compute PTE address */		\
338	lwz	r11, 0(r12);		/* Get Linux PTE */
339#endif
340
341/*
342 * Interrupt vector entry code
343 *
344 * The Book E MMUs are always on so we don't need to handle
345 * interrupts in real mode as with previous PPC processors. In
346 * this case we handle interrupts in the kernel virtual address
347 * space.
348 *
349 * Interrupt vectors are dynamically placed relative to the
350 * interrupt prefix as determined by the address of interrupt_base.
351 * The interrupt vectors offsets are programmed using the labels
352 * for each interrupt vector entry.
353 *
354 * Interrupt vectors must be aligned on a 16 byte boundary.
355 * We align on a 32 byte cache line boundary for good measure.
356 */
357
358interrupt_base:
359	/* Critical Input Interrupt */
360	CRITICAL_EXCEPTION(0x0100, CRITICAL, CriticalInput, unknown_exception)
361
362	/* Machine Check Interrupt */
363	MCHECK_EXCEPTION(0x0200, MachineCheck, machine_check_exception)
364
365	/* Data Storage Interrupt */
366	START_EXCEPTION(DataStorage)
367	NORMAL_EXCEPTION_PROLOG(0x300, DATA_STORAGE)
368	mfspr	r5,SPRN_ESR		/* Grab the ESR, save it */
369	stw	r5,_ESR(r11)
370	mfspr	r4,SPRN_DEAR		/* Grab the DEAR, save it */
371	stw	r4, _DEAR(r11)
372	andis.	r10,r5,(ESR_ILK|ESR_DLK)@h
373	bne	1f
374	prepare_transfer_to_handler
375	bl	do_page_fault
376	b	interrupt_return
3771:
378	prepare_transfer_to_handler
379	bl	CacheLockingException
380	b	interrupt_return
381
382	/* Instruction Storage Interrupt */
383	INSTRUCTION_STORAGE_EXCEPTION
384
385	/* External Input Interrupt */
386	EXCEPTION(0x0500, EXTERNAL, ExternalInput, do_IRQ)
387
388	/* Alignment Interrupt */
389	ALIGNMENT_EXCEPTION
390
391	/* Program Interrupt */
392	PROGRAM_EXCEPTION
393
394	/* Floating Point Unavailable Interrupt */
395#ifdef CONFIG_PPC_FPU
396	FP_UNAVAILABLE_EXCEPTION
397#else
398	EXCEPTION(0x0800, FP_UNAVAIL, FloatingPointUnavailable, unknown_exception)
399#endif
400
401	/* System Call Interrupt */
402	START_EXCEPTION(SystemCall)
403	SYSCALL_ENTRY   0xc00 BOOKE_INTERRUPT_SYSCALL SPRN_SRR1
404
405	/* Auxiliary Processor Unavailable Interrupt */
406	EXCEPTION(0x2900, AP_UNAVAIL, AuxillaryProcessorUnavailable, unknown_exception)
407
408	/* Decrementer Interrupt */
409	DECREMENTER_EXCEPTION
410
411	/* Fixed Internal Timer Interrupt */
412	/* TODO: Add FIT support */
413	EXCEPTION(0x3100, FIT, FixedIntervalTimer, unknown_exception)
414
415	/* Watchdog Timer Interrupt */
416#ifdef CONFIG_BOOKE_WDT
417	CRITICAL_EXCEPTION(0x3200, WATCHDOG, WatchdogTimer, WatchdogException)
418#else
419	CRITICAL_EXCEPTION(0x3200, WATCHDOG, WatchdogTimer, unknown_exception)
420#endif
421
422	/* Data TLB Error Interrupt */
423	START_EXCEPTION(DataTLBError)
424	mtspr	SPRN_SPRG_WSCRATCH0, r10 /* Save some working registers */
425	mfspr	r10, SPRN_SPRG_THREAD
426	stw	r11, THREAD_NORMSAVE(0)(r10)
427#ifdef CONFIG_KVM_BOOKE_HV
428BEGIN_FTR_SECTION
429	mfspr	r11, SPRN_SRR1
430END_FTR_SECTION_IFSET(CPU_FTR_EMB_HV)
431#endif
432	stw	r12, THREAD_NORMSAVE(1)(r10)
433	stw	r13, THREAD_NORMSAVE(2)(r10)
434	mfcr	r13
435	stw	r13, THREAD_NORMSAVE(3)(r10)
436	DO_KVM	BOOKE_INTERRUPT_DTLB_MISS SPRN_SRR1
437START_BTB_FLUSH_SECTION
438	mfspr r11, SPRN_SRR1
439	andi. r10,r11,MSR_PR
440	beq 1f
441	BTB_FLUSH(r10)
4421:
443END_BTB_FLUSH_SECTION
444	mfspr	r10, SPRN_DEAR		/* Get faulting address */
445
446	/* If we are faulting a kernel address, we have to use the
447	 * kernel page tables.
448	 */
449	lis	r11, PAGE_OFFSET@h
450	cmplw	5, r10, r11
451	blt	5, 3f
452	lis	r11, swapper_pg_dir@h
453	ori	r11, r11, swapper_pg_dir@l
454
455	mfspr	r12,SPRN_MAS1		/* Set TID to 0 */
456	rlwinm	r12,r12,0,16,1
457	mtspr	SPRN_MAS1,r12
458
459	b	4f
460
461	/* Get the PGD for the current thread */
4623:
463	mfspr	r11,SPRN_SPRG_THREAD
464	lwz	r11,PGDIR(r11)
465
466#ifdef CONFIG_PPC_KUAP
467	mfspr	r12, SPRN_MAS1
468	rlwinm.	r12,r12,0,0x3fff0000
469	beq	2f			/* KUAP fault */
470#endif
471
4724:
473	/* Mask of required permission bits. Note that while we
474	 * do copy ESR:ST to _PAGE_RW position as trying to write
475	 * to an RO page is pretty common, we don't do it with
476	 * _PAGE_DIRTY. We could do it, but it's a fairly rare
477	 * event so I'd rather take the overhead when it happens
478	 * rather than adding an instruction here. We should measure
479	 * whether the whole thing is worth it in the first place
480	 * as we could avoid loading SPRN_ESR completely in the first
481	 * place...
482	 *
483	 * TODO: Is it worth doing that mfspr & rlwimi in the first
484	 *       place or can we save a couple of instructions here ?
485	 */
486	mfspr	r12,SPRN_ESR
487#ifdef CONFIG_PTE_64BIT
488	li	r13,_PAGE_PRESENT
489	oris	r13,r13,_PAGE_ACCESSED@h
490#else
491	li	r13,_PAGE_PRESENT|_PAGE_ACCESSED
492#endif
493	rlwimi	r13,r12,11,29,29
494
495	FIND_PTE
496	andc.	r13,r13,r11		/* Check permission */
497
498#ifdef CONFIG_PTE_64BIT
499#ifdef CONFIG_SMP
500	subf	r13,r11,r12		/* create false data dep */
501	lwzx	r13,r11,r13		/* Get upper pte bits */
502#else
503	lwz	r13,0(r12)		/* Get upper pte bits */
504#endif
505#endif
506
507	bne	2f			/* Bail if permission/valid mismatch */
508
509	/* Jump to common tlb load */
510	b	finish_tlb_load
5112:
512	/* The bailout.  Restore registers to pre-exception conditions
513	 * and call the heavyweights to help us out.
514	 */
515	mfspr	r10, SPRN_SPRG_THREAD
516	lwz	r11, THREAD_NORMSAVE(3)(r10)
517	mtcr	r11
518	lwz	r13, THREAD_NORMSAVE(2)(r10)
519	lwz	r12, THREAD_NORMSAVE(1)(r10)
520	lwz	r11, THREAD_NORMSAVE(0)(r10)
521	mfspr	r10, SPRN_SPRG_RSCRATCH0
522	b	DataStorage
523
524	/* Instruction TLB Error Interrupt */
525	/*
526	 * Nearly the same as above, except we get our
527	 * information from different registers and bailout
528	 * to a different point.
529	 */
530	START_EXCEPTION(InstructionTLBError)
531	mtspr	SPRN_SPRG_WSCRATCH0, r10 /* Save some working registers */
532	mfspr	r10, SPRN_SPRG_THREAD
533	stw	r11, THREAD_NORMSAVE(0)(r10)
534#ifdef CONFIG_KVM_BOOKE_HV
535BEGIN_FTR_SECTION
536	mfspr	r11, SPRN_SRR1
537END_FTR_SECTION_IFSET(CPU_FTR_EMB_HV)
538#endif
539	stw	r12, THREAD_NORMSAVE(1)(r10)
540	stw	r13, THREAD_NORMSAVE(2)(r10)
541	mfcr	r13
542	stw	r13, THREAD_NORMSAVE(3)(r10)
543	DO_KVM	BOOKE_INTERRUPT_ITLB_MISS SPRN_SRR1
544START_BTB_FLUSH_SECTION
545	mfspr r11, SPRN_SRR1
546	andi. r10,r11,MSR_PR
547	beq 1f
548	BTB_FLUSH(r10)
5491:
550END_BTB_FLUSH_SECTION
551
552	mfspr	r10, SPRN_SRR0		/* Get faulting address */
553
554	/* If we are faulting a kernel address, we have to use the
555	 * kernel page tables.
556	 */
557	lis	r11, PAGE_OFFSET@h
558	cmplw	5, r10, r11
559	blt	5, 3f
560	lis	r11, swapper_pg_dir@h
561	ori	r11, r11, swapper_pg_dir@l
562
563	mfspr	r12,SPRN_MAS1		/* Set TID to 0 */
564	rlwinm	r12,r12,0,16,1
565	mtspr	SPRN_MAS1,r12
566
567	/* Make up the required permissions for kernel code */
568#ifdef CONFIG_PTE_64BIT
569	li	r13,_PAGE_PRESENT | _PAGE_BAP_SX
570	oris	r13,r13,_PAGE_ACCESSED@h
571#else
572	li	r13,_PAGE_PRESENT | _PAGE_ACCESSED | _PAGE_EXEC
573#endif
574	b	4f
575
576	/* Get the PGD for the current thread */
5773:
578	mfspr	r11,SPRN_SPRG_THREAD
579	lwz	r11,PGDIR(r11)
580
581#ifdef CONFIG_PPC_KUAP
582	mfspr	r12, SPRN_MAS1
583	rlwinm.	r12,r12,0,0x3fff0000
584	beq	2f			/* KUAP fault */
585#endif
586
587	/* Make up the required permissions for user code */
588#ifdef CONFIG_PTE_64BIT
589	li	r13,_PAGE_PRESENT | _PAGE_BAP_UX
590	oris	r13,r13,_PAGE_ACCESSED@h
591#else
592	li	r13,_PAGE_PRESENT | _PAGE_ACCESSED | _PAGE_EXEC
593#endif
594
5954:
596	FIND_PTE
597	andc.	r13,r13,r11		/* Check permission */
598
599#ifdef CONFIG_PTE_64BIT
600#ifdef CONFIG_SMP
601	subf	r13,r11,r12		/* create false data dep */
602	lwzx	r13,r11,r13		/* Get upper pte bits */
603#else
604	lwz	r13,0(r12)		/* Get upper pte bits */
605#endif
606#endif
607
608	bne	2f			/* Bail if permission mismatch */
609
610	/* Jump to common TLB load point */
611	b	finish_tlb_load
612
6132:
614	/* The bailout.  Restore registers to pre-exception conditions
615	 * and call the heavyweights to help us out.
616	 */
617	mfspr	r10, SPRN_SPRG_THREAD
618	lwz	r11, THREAD_NORMSAVE(3)(r10)
619	mtcr	r11
620	lwz	r13, THREAD_NORMSAVE(2)(r10)
621	lwz	r12, THREAD_NORMSAVE(1)(r10)
622	lwz	r11, THREAD_NORMSAVE(0)(r10)
623	mfspr	r10, SPRN_SPRG_RSCRATCH0
624	b	InstructionStorage
625
626/* Define SPE handlers for e500v2 */
627#ifdef CONFIG_SPE
628	/* SPE Unavailable */
629	START_EXCEPTION(SPEUnavailable)
630	NORMAL_EXCEPTION_PROLOG(0x2010, SPE_UNAVAIL)
631	beq	1f
632	bl	load_up_spe
633	b	fast_exception_return
6341:	prepare_transfer_to_handler
635	bl	KernelSPE
636	b	interrupt_return
637#elif defined(CONFIG_SPE_POSSIBLE)
638	EXCEPTION(0x2020, SPE_UNAVAIL, SPEUnavailable, unknown_exception)
639#endif /* CONFIG_SPE_POSSIBLE */
640
641	/* SPE Floating Point Data */
642#ifdef CONFIG_SPE
643	START_EXCEPTION(SPEFloatingPointData)
644	NORMAL_EXCEPTION_PROLOG(0x2030, SPE_FP_DATA)
645	prepare_transfer_to_handler
646	bl	SPEFloatingPointException
647	REST_NVGPRS(r1)
648	b	interrupt_return
649
650	/* SPE Floating Point Round */
651	START_EXCEPTION(SPEFloatingPointRound)
652	NORMAL_EXCEPTION_PROLOG(0x2050, SPE_FP_ROUND)
653	prepare_transfer_to_handler
654	bl	SPEFloatingPointRoundException
655	REST_NVGPRS(r1)
656	b	interrupt_return
657#elif defined(CONFIG_SPE_POSSIBLE)
658	EXCEPTION(0x2040, SPE_FP_DATA, SPEFloatingPointData, unknown_exception)
659	EXCEPTION(0x2050, SPE_FP_ROUND, SPEFloatingPointRound, unknown_exception)
660#endif /* CONFIG_SPE_POSSIBLE */
661
662
663	/* Performance Monitor */
664	EXCEPTION(0x2060, PERFORMANCE_MONITOR, PerformanceMonitor, \
665		  performance_monitor_exception)
666
667	EXCEPTION(0x2070, DOORBELL, Doorbell, doorbell_exception)
668
669	CRITICAL_EXCEPTION(0x2080, DOORBELL_CRITICAL, \
670			   CriticalDoorbell, unknown_exception)
671
672	/* Debug Interrupt */
673	DEBUG_DEBUG_EXCEPTION
674	DEBUG_CRIT_EXCEPTION
675
676	GUEST_DOORBELL_EXCEPTION
677
678	CRITICAL_EXCEPTION(0, GUEST_DBELL_CRIT, CriticalGuestDoorbell, \
679			   unknown_exception)
680
681	/* Hypercall */
682	EXCEPTION(0, HV_SYSCALL, Hypercall, unknown_exception)
683
684	/* Embedded Hypervisor Privilege */
685	EXCEPTION(0, HV_PRIV, Ehvpriv, unknown_exception)
686
687interrupt_end:
688
689/*
690 * Local functions
691 */
692
693/*
694 * Both the instruction and data TLB miss get to this
695 * point to load the TLB.
696 *	r10 - tsize encoding (if HUGETLB_PAGE) or available to use
697 *	r11 - TLB (info from Linux PTE)
698 *	r12 - available to use
699 *	r13 - upper bits of PTE (if PTE_64BIT) or available to use
700 *	CR5 - results of addr >= PAGE_OFFSET
701 *	MAS0, MAS1 - loaded with proper value when we get here
702 *	MAS2, MAS3 - will need additional info from Linux PTE
703 *	Upon exit, we reload everything and RFI.
704 */
705finish_tlb_load:
706#ifdef CONFIG_HUGETLB_PAGE
707	cmpwi	6, r10, 0			/* check for huge page */
708	beq	6, finish_tlb_load_cont    	/* !huge */
709
710	/* Alas, we need more scratch registers for hugepages */
711	mfspr	r12, SPRN_SPRG_THREAD
712	stw	r14, THREAD_NORMSAVE(4)(r12)
713	stw	r15, THREAD_NORMSAVE(5)(r12)
714	stw	r16, THREAD_NORMSAVE(6)(r12)
715	stw	r17, THREAD_NORMSAVE(7)(r12)
716
717	/* Get the next_tlbcam_idx percpu var */
718#ifdef CONFIG_SMP
719	lwz	r15, TASK_CPU-THREAD(r12)
720	lis     r14, __per_cpu_offset@h
721	ori     r14, r14, __per_cpu_offset@l
722	rlwinm  r15, r15, 2, 0, 29
723	lwzx    r16, r14, r15
724#else
725	li	r16, 0
726#endif
727	lis     r17, next_tlbcam_idx@h
728	ori	r17, r17, next_tlbcam_idx@l
729	add	r17, r17, r16			/* r17 = *next_tlbcam_idx */
730	lwz     r15, 0(r17)			/* r15 = next_tlbcam_idx */
731
732	lis	r14, MAS0_TLBSEL(1)@h		/* select TLB1 (TLBCAM) */
733	rlwimi	r14, r15, 16, 4, 15		/* next_tlbcam_idx entry */
734	mtspr	SPRN_MAS0, r14
735
736	/* Extract TLB1CFG(NENTRY) */
737	mfspr	r16, SPRN_TLB1CFG
738	andi.	r16, r16, 0xfff
739
740	/* Update next_tlbcam_idx, wrapping when necessary */
741	addi	r15, r15, 1
742	cmpw	r15, r16
743	blt 	100f
744	lis	r14, tlbcam_index@h
745	ori	r14, r14, tlbcam_index@l
746	lwz	r15, 0(r14)
747100:	stw	r15, 0(r17)
748
749	/*
750	 * Calc MAS1_TSIZE from r10 (which has pshift encoded)
751	 * tlb_enc = (pshift - 10).
752	 */
753	subi	r15, r10, 10
754	mfspr	r16, SPRN_MAS1
755	rlwimi	r16, r15, 7, 20, 24
756	mtspr	SPRN_MAS1, r16
757
758	/* copy the pshift for use later */
759	mr	r14, r10
760
761	/* fall through */
762
763#endif /* CONFIG_HUGETLB_PAGE */
764
765	/*
766	 * We set execute, because we don't have the granularity to
767	 * properly set this at the page level (Linux problem).
768	 * Many of these bits are software only.  Bits we don't set
769	 * here we (properly should) assume have the appropriate value.
770	 */
771finish_tlb_load_cont:
772#ifdef CONFIG_PTE_64BIT
773	rlwinm	r12, r11, 32-2, 26, 31	/* Move in perm bits */
774	andi.	r10, r11, _PAGE_DIRTY
775	bne	1f
776	li	r10, MAS3_SW | MAS3_UW
777	andc	r12, r12, r10
7781:	rlwimi	r12, r13, 20, 0, 11	/* grab RPN[32:43] */
779	rlwimi	r12, r11, 20, 12, 19	/* grab RPN[44:51] */
7802:	mtspr	SPRN_MAS3, r12
781BEGIN_MMU_FTR_SECTION
782	srwi	r10, r13, 12		/* grab RPN[12:31] */
783	mtspr	SPRN_MAS7, r10
784END_MMU_FTR_SECTION_IFSET(MMU_FTR_BIG_PHYS)
785#else
786	li	r10, (_PAGE_EXEC | _PAGE_PRESENT)
787	mr	r13, r11
788	rlwimi	r10, r11, 31, 29, 29	/* extract _PAGE_DIRTY into SW */
789	and	r12, r11, r10
790	andi.	r10, r11, _PAGE_USER	/* Test for _PAGE_USER */
791	slwi	r10, r12, 1
792	or	r10, r10, r12
793	rlwinm	r10, r10, 0, ~_PAGE_EXEC	/* Clear SX on user pages */
794	iseleq	r12, r12, r10
795	rlwimi	r13, r12, 0, 20, 31	/* Get RPN from PTE, merge w/ perms */
796	mtspr	SPRN_MAS3, r13
797#endif
798
799	mfspr	r12, SPRN_MAS2
800#ifdef CONFIG_PTE_64BIT
801	rlwimi	r12, r11, 32-19, 27, 31	/* extract WIMGE from pte */
802#else
803	rlwimi	r12, r11, 26, 27, 31	/* extract WIMGE from pte */
804#endif
805#ifdef CONFIG_HUGETLB_PAGE
806	beq	6, 3f			/* don't mask if page isn't huge */
807	li	r13, 1
808	slw	r13, r13, r14
809	subi	r13, r13, 1
810	rlwinm	r13, r13, 0, 0, 19	/* bottom bits used for WIMGE/etc */
811	andc	r12, r12, r13		/* mask off ea bits within the page */
812#endif
8133:	mtspr	SPRN_MAS2, r12
814
815tlb_write_entry:
816	tlbwe
817
818	/* Done...restore registers and get out of here.  */
819	mfspr	r10, SPRN_SPRG_THREAD
820#ifdef CONFIG_HUGETLB_PAGE
821	beq	6, 8f /* skip restore for 4k page faults */
822	lwz	r14, THREAD_NORMSAVE(4)(r10)
823	lwz	r15, THREAD_NORMSAVE(5)(r10)
824	lwz	r16, THREAD_NORMSAVE(6)(r10)
825	lwz	r17, THREAD_NORMSAVE(7)(r10)
826#endif
8278:	lwz	r11, THREAD_NORMSAVE(3)(r10)
828	mtcr	r11
829	lwz	r13, THREAD_NORMSAVE(2)(r10)
830	lwz	r12, THREAD_NORMSAVE(1)(r10)
831	lwz	r11, THREAD_NORMSAVE(0)(r10)
832	mfspr	r10, SPRN_SPRG_RSCRATCH0
833	rfi					/* Force context change */
834
835#ifdef CONFIG_SPE
836/* Note that the SPE support is closely modeled after the AltiVec
837 * support.  Changes to one are likely to be applicable to the
838 * other!  */
839_GLOBAL(load_up_spe)
840/*
841 * Disable SPE for the task which had SPE previously,
842 * and save its SPE registers in its thread_struct.
843 * Enables SPE for use in the kernel on return.
844 * On SMP we know the SPE units are free, since we give it up every
845 * switch.  -- Kumar
846 */
847	mfmsr	r5
848	oris	r5,r5,MSR_SPE@h
849	mtmsr	r5			/* enable use of SPE now */
850	isync
851	/* enable use of SPE after return */
852	oris	r9,r9,MSR_SPE@h
853	mfspr	r5,SPRN_SPRG_THREAD	/* current task's THREAD (phys) */
854	li	r4,1
855	li	r10,THREAD_ACC
856	stw	r4,THREAD_USED_SPE(r5)
857	evlddx	evr4,r10,r5
858	evmra	evr4,evr4
859	REST_32EVRS(0,r10,r5,THREAD_EVR0)
860	blr
861
862/*
863 * SPE unavailable trap from kernel - print a message, but let
864 * the task use SPE in the kernel until it returns to user mode.
865 */
866SYM_FUNC_START_LOCAL(KernelSPE)
867	lwz	r3,_MSR(r1)
868	oris	r3,r3,MSR_SPE@h
869	stw	r3,_MSR(r1)	/* enable use of SPE after return */
870#ifdef CONFIG_PRINTK
871	lis	r3,87f@h
872	ori	r3,r3,87f@l
873	mr	r4,r2		/* current */
874	lwz	r5,_NIP(r1)
875	bl	_printk
876#endif
877	b	interrupt_return
878#ifdef CONFIG_PRINTK
87987:	.string	"SPE used in kernel  (task=%p, pc=%x)  \n"
880#endif
881	.align	4,0
882
883SYM_FUNC_END(KernelSPE)
884#endif /* CONFIG_SPE */
885
886/*
887 * Translate the effec addr in r3 to phys addr. The phys addr will be put
888 * into r3(higher 32bit) and r4(lower 32bit)
889 */
890SYM_FUNC_START_LOCAL(get_phys_addr)
891	mfmsr	r8
892	mfspr	r9,SPRN_PID
893	rlwinm	r9,r9,16,0x3fff0000	/* turn PID into MAS6[SPID] */
894	rlwimi	r9,r8,28,0x00000001	/* turn MSR[DS] into MAS6[SAS] */
895	mtspr	SPRN_MAS6,r9
896
897	tlbsx	0,r3			/* must succeed */
898
899	mfspr	r8,SPRN_MAS1
900	mfspr	r12,SPRN_MAS3
901	rlwinm	r9,r8,25,0x1f		/* r9 = log2(page size) */
902	li	r10,1024
903	slw	r10,r10,r9		/* r10 = page size */
904	addi	r10,r10,-1
905	and	r11,r3,r10		/* r11 = page offset */
906	andc	r4,r12,r10		/* r4 = page base */
907	or	r4,r4,r11		/* r4 = devtree phys addr */
908#ifdef CONFIG_PHYS_64BIT
909	mfspr	r3,SPRN_MAS7
910#endif
911	blr
912SYM_FUNC_END(get_phys_addr)
913
914/*
915 * Global functions
916 */
917
918#ifdef CONFIG_PPC_E500
919#ifndef CONFIG_PPC_E500MC
920/* Adjust or setup IVORs for e500v1/v2 */
921_GLOBAL(__setup_e500_ivors)
922	li	r3,DebugCrit@l
923	mtspr	SPRN_IVOR15,r3
924	li	r3,SPEUnavailable@l
925	mtspr	SPRN_IVOR32,r3
926	li	r3,SPEFloatingPointData@l
927	mtspr	SPRN_IVOR33,r3
928	li	r3,SPEFloatingPointRound@l
929	mtspr	SPRN_IVOR34,r3
930	li	r3,PerformanceMonitor@l
931	mtspr	SPRN_IVOR35,r3
932	sync
933	blr
934#else
935/* Adjust or setup IVORs for e500mc */
936_GLOBAL(__setup_e500mc_ivors)
937	li	r3,DebugDebug@l
938	mtspr	SPRN_IVOR15,r3
939	li	r3,PerformanceMonitor@l
940	mtspr	SPRN_IVOR35,r3
941	li	r3,Doorbell@l
942	mtspr	SPRN_IVOR36,r3
943	li	r3,CriticalDoorbell@l
944	mtspr	SPRN_IVOR37,r3
945	sync
946	blr
947
948/* setup ehv ivors for */
949_GLOBAL(__setup_ehv_ivors)
950	li	r3,GuestDoorbell@l
951	mtspr	SPRN_IVOR38,r3
952	li	r3,CriticalGuestDoorbell@l
953	mtspr	SPRN_IVOR39,r3
954	li	r3,Hypercall@l
955	mtspr	SPRN_IVOR40,r3
956	li	r3,Ehvpriv@l
957	mtspr	SPRN_IVOR41,r3
958	sync
959	blr
960#endif /* CONFIG_PPC_E500MC */
961#endif /* CONFIG_PPC_E500 */
962
963#ifdef CONFIG_SPE
964/*
965 * extern void __giveup_spe(struct task_struct *prev)
966 *
967 */
968_GLOBAL(__giveup_spe)
969	addi	r3,r3,THREAD		/* want THREAD of task */
970	lwz	r5,PT_REGS(r3)
971	cmpi	0,r5,0
972	SAVE_32EVRS(0, r4, r3, THREAD_EVR0)
973	evxor	evr6, evr6, evr6	/* clear out evr6 */
974	evmwumiaa evr6, evr6, evr6	/* evr6 <- ACC = 0 * 0 + ACC */
975	li	r4,THREAD_ACC
976	evstddx	evr6, r4, r3		/* save off accumulator */
977	beq	1f
978	lwz	r4,_MSR-STACK_INT_FRAME_REGS(r5)
979	lis	r3,MSR_SPE@h
980	andc	r4,r4,r3		/* disable SPE for previous task */
981	stw	r4,_MSR-STACK_INT_FRAME_REGS(r5)
9821:
983	blr
984#endif /* CONFIG_SPE */
985
986/*
987 * extern void abort(void)
988 *
989 * At present, this routine just applies a system reset.
990 */
991_GLOBAL(abort)
992	li	r13,0
993	mtspr	SPRN_DBCR0,r13		/* disable all debug events */
994	isync
995	mfmsr	r13
996	ori	r13,r13,MSR_DE@l	/* Enable Debug Events */
997	mtmsr	r13
998	isync
999	mfspr	r13,SPRN_DBCR0
1000	lis	r13,(DBCR0_IDM|DBCR0_RST_CHIP)@h
1001	mtspr	SPRN_DBCR0,r13
1002	isync
1003
1004#ifdef CONFIG_SMP
1005/* When we get here, r24 needs to hold the CPU # */
1006	.globl __secondary_start
1007__secondary_start:
1008	LOAD_REG_ADDR_PIC(r3, tlbcam_index)
1009	lwz	r3,0(r3)
1010	mtctr	r3
1011	li	r26,0		/* r26 safe? */
1012
1013	bl	switch_to_as1
1014	mr	r27,r3		/* tlb entry */
1015	/* Load each CAM entry */
10161:	mr	r3,r26
1017	bl	loadcam_entry
1018	addi	r26,r26,1
1019	bdnz	1b
1020	mr	r3,r27		/* tlb entry */
1021	LOAD_REG_ADDR_PIC(r4, memstart_addr)
1022	lwz	r4,0(r4)
1023	mr	r5,r25		/* phys kernel start */
1024	rlwinm	r5,r5,0,~0x3ffffff	/* aligned 64M */
1025	subf	r4,r5,r4	/* memstart_addr - phys kernel start */
1026	lis	r7,KERNELBASE@h
1027	ori	r7,r7,KERNELBASE@l
1028	cmpw	r20,r7		/* if kernstart_virt_addr != KERNELBASE, randomized */
1029	beq	2f
1030	li	r4,0
10312:	li	r5,0		/* no device tree */
1032	li	r6,0		/* not boot cpu */
1033	bl	restore_to_as0
1034
1035
1036	lis	r3,__secondary_hold_acknowledge@h
1037	ori	r3,r3,__secondary_hold_acknowledge@l
1038	stw	r24,0(r3)
1039
1040	li	r3,0
1041	mr	r4,r24		/* Why? */
1042	bl	call_setup_cpu
1043
1044	/* get current's stack and current */
1045	lis	r2,secondary_current@ha
1046	lwz	r2,secondary_current@l(r2)
1047	lwz	r1,TASK_STACK(r2)
1048
1049	/* stack */
1050	addi	r1,r1,THREAD_SIZE-STACK_FRAME_MIN_SIZE
1051	li	r0,0
1052	stw	r0,0(r1)
1053
1054	/* ptr to current thread */
1055	addi	r4,r2,THREAD	/* address of our thread_struct */
1056	mtspr	SPRN_SPRG_THREAD,r4
1057
1058	/* Setup the defaults for TLB entries */
1059	li	r4,(MAS4_TSIZED(BOOK3E_PAGESZ_4K))@l
1060	mtspr	SPRN_MAS4,r4
1061
1062	/* Jump to start_secondary */
1063	lis	r4,MSR_KERNEL@h
1064	ori	r4,r4,MSR_KERNEL@l
1065	lis	r3,start_secondary@h
1066	ori	r3,r3,start_secondary@l
1067	mtspr	SPRN_SRR0,r3
1068	mtspr	SPRN_SRR1,r4
1069	sync
1070	rfi
1071	sync
1072
1073	.globl __secondary_hold_acknowledge
1074__secondary_hold_acknowledge:
1075	.long	-1
1076#endif
1077
1078/*
1079 * Create a 64M tlb by address and entry
1080 * r3 - entry
1081 * r4 - virtual address
1082 * r5/r6 - physical address
1083 */
1084_GLOBAL(create_kaslr_tlb_entry)
1085	lis     r7,0x1000               /* Set MAS0(TLBSEL) = 1 */
1086	rlwimi  r7,r3,16,4,15           /* Setup MAS0 = TLBSEL | ESEL(r6) */
1087	mtspr   SPRN_MAS0,r7            /* Write MAS0 */
1088
1089	lis     r3,(MAS1_VALID|MAS1_IPROT)@h
1090	ori     r3,r3,(MAS1_TSIZE(BOOK3E_PAGESZ_64M))@l
1091	mtspr   SPRN_MAS1,r3            /* Write MAS1 */
1092
1093	lis     r3,MAS2_EPN_MASK(BOOK3E_PAGESZ_64M)@h
1094	ori     r3,r3,MAS2_EPN_MASK(BOOK3E_PAGESZ_64M)@l
1095	and     r3,r3,r4
1096	ori	r3,r3,MAS2_M_IF_NEEDED@l
1097	mtspr   SPRN_MAS2,r3            /* Write MAS2(EPN) */
1098
1099#ifdef CONFIG_PHYS_64BIT
1100	ori     r8,r6,(MAS3_SW|MAS3_SR|MAS3_SX)
1101	mtspr   SPRN_MAS3,r8            /* Write MAS3(RPN) */
1102	mtspr	SPRN_MAS7,r5
1103#else
1104	ori     r8,r5,(MAS3_SW|MAS3_SR|MAS3_SX)
1105	mtspr   SPRN_MAS3,r8            /* Write MAS3(RPN) */
1106#endif
1107
1108	tlbwe                           /* Write TLB */
1109	isync
1110	sync
1111	blr
1112
1113/*
1114 * Return to the start of the relocated kernel and run again
1115 * r3 - virtual address of fdt
1116 * r4 - entry of the kernel
1117 */
1118_GLOBAL(reloc_kernel_entry)
1119	mfmsr	r7
1120	rlwinm	r7, r7, 0, ~(MSR_IS | MSR_DS)
1121
1122	mtspr	SPRN_SRR0,r4
1123	mtspr	SPRN_SRR1,r7
1124	rfi
1125
1126/*
1127 * Create a tlb entry with the same effective and physical address as
1128 * the tlb entry used by the current running code. But set the TS to 1.
1129 * Then switch to the address space 1. It will return with the r3 set to
1130 * the ESEL of the new created tlb.
1131 */
1132_GLOBAL(switch_to_as1)
1133	mflr	r5
1134
1135	/* Find a entry not used */
1136	mfspr	r3,SPRN_TLB1CFG
1137	andi.	r3,r3,0xfff
1138	mfspr	r4,SPRN_PID
1139	rlwinm	r4,r4,16,0x3fff0000	/* turn PID into MAS6[SPID] */
1140	mtspr	SPRN_MAS6,r4
11411:	lis	r4,0x1000		/* Set MAS0(TLBSEL) = 1 */
1142	addi	r3,r3,-1
1143	rlwimi	r4,r3,16,4,15		/* Setup MAS0 = TLBSEL | ESEL(r3) */
1144	mtspr	SPRN_MAS0,r4
1145	tlbre
1146	mfspr	r4,SPRN_MAS1
1147	andis.	r4,r4,MAS1_VALID@h
1148	bne	1b
1149
1150	/* Get the tlb entry used by the current running code */
1151	bcl	20,31,$+4
11520:	mflr	r4
1153	tlbsx	0,r4
1154
1155	mfspr	r4,SPRN_MAS1
1156	ori	r4,r4,MAS1_TS		/* Set the TS = 1 */
1157	mtspr	SPRN_MAS1,r4
1158
1159	mfspr	r4,SPRN_MAS0
1160	rlwinm	r4,r4,0,~MAS0_ESEL_MASK
1161	rlwimi	r4,r3,16,4,15		/* Setup MAS0 = TLBSEL | ESEL(r3) */
1162	mtspr	SPRN_MAS0,r4
1163	tlbwe
1164	isync
1165	sync
1166
1167	mfmsr	r4
1168	ori	r4,r4,MSR_IS | MSR_DS
1169	mtspr	SPRN_SRR0,r5
1170	mtspr	SPRN_SRR1,r4
1171	sync
1172	rfi
1173
1174/*
1175 * Restore to the address space 0 and also invalidate the tlb entry created
1176 * by switch_to_as1.
1177 * r3 - the tlb entry which should be invalidated
1178 * r4 - __pa(PAGE_OFFSET in AS1) - __pa(PAGE_OFFSET in AS0)
1179 * r5 - device tree virtual address. If r4 is 0, r5 is ignored.
1180 * r6 - boot cpu
1181*/
1182_GLOBAL(restore_to_as0)
1183	mflr	r0
1184
1185	bcl	20,31,$+4
11860:	mflr	r9
1187	addi	r9,r9,1f - 0b
1188
1189	/*
1190	 * We may map the PAGE_OFFSET in AS0 to a different physical address,
1191	 * so we need calculate the right jump and device tree address based
1192	 * on the offset passed by r4.
1193	 */
1194	add	r9,r9,r4
1195	add	r5,r5,r4
1196	add	r0,r0,r4
1197
11982:	mfmsr	r7
1199	li	r8,(MSR_IS | MSR_DS)
1200	andc	r7,r7,r8
1201
1202	mtspr	SPRN_SRR0,r9
1203	mtspr	SPRN_SRR1,r7
1204	sync
1205	rfi
1206
1207	/* Invalidate the temporary tlb entry for AS1 */
12081:	lis	r9,0x1000		/* Set MAS0(TLBSEL) = 1 */
1209	rlwimi	r9,r3,16,4,15		/* Setup MAS0 = TLBSEL | ESEL(r3) */
1210	mtspr	SPRN_MAS0,r9
1211	tlbre
1212	mfspr	r9,SPRN_MAS1
1213	rlwinm	r9,r9,0,2,31		/* Clear MAS1 Valid and IPPROT */
1214	mtspr	SPRN_MAS1,r9
1215	tlbwe
1216	isync
1217
1218	cmpwi	r4,0
1219	cmpwi	cr1,r6,0
1220	cror	eq,4*cr1+eq,eq
1221	bne	3f			/* offset != 0 && is_boot_cpu */
1222	mtlr	r0
1223	blr
1224
1225	/*
1226	 * The PAGE_OFFSET will map to a different physical address,
1227	 * jump to _start to do another relocation again.
1228	*/
12293:	mr	r3,r5
1230	bl	_start
1231