xref: /openbmc/linux/arch/powerpc/kexec/relocate_32.S (revision 65844828) 
1/* SPDX-License-Identifier: GPL-2.0-or-later */
2/*
3 * This file contains kexec low-level functions.
4 *
5 * Copyright (C) 2002-2003 Eric Biederman  <ebiederm@xmission.com>
6 * GameCube/ppc32 port Copyright (C) 2004 Albert Herranz
7 * PPC44x port. Copyright (C) 2011,  IBM Corporation
8 * 		Author: Suzuki Poulose <suzuki@in.ibm.com>
9 */
10
11#include <asm/reg.h>
12#include <asm/page.h>
13#include <asm/mmu.h>
14#include <asm/ppc_asm.h>
15#include <asm/kexec.h>
16
17	.text
18
19	/*
20	 * Must be relocatable PIC code callable as a C function.
21	 */
22	.globl relocate_new_kernel
23relocate_new_kernel:
24	/* r3 = page_list   */
25	/* r4 = reboot_code_buffer */
26	/* r5 = start_address      */
27
28#ifdef CONFIG_PPC_85xx
29
30	mr	r29, r3
31	mr	r30, r4
32	mr	r31, r5
33
34#define ENTRY_MAPPING_KEXEC_SETUP
35#include <kernel/85xx_entry_mapping.S>
36#undef ENTRY_MAPPING_KEXEC_SETUP
37
38	mr      r3, r29
39	mr      r4, r30
40	mr      r5, r31
41
42	li	r0, 0
43#elif defined(CONFIG_44x)
44
45	/* Save our parameters */
46	mr	r29, r3
47	mr	r30, r4
48	mr	r31, r5
49
50#ifdef CONFIG_PPC_47x
51	/* Check for 47x cores */
52	mfspr	r3,SPRN_PVR
53	srwi	r3,r3,16
54	cmplwi	cr0,r3,PVR_476FPE@h
55	beq	setup_map_47x
56	cmplwi	cr0,r3,PVR_476@h
57	beq	setup_map_47x
58	cmplwi	cr0,r3,PVR_476_ISS@h
59	beq	setup_map_47x
60#endif /* CONFIG_PPC_47x */
61
62/*
63 * Code for setting up 1:1 mapping for PPC440x for KEXEC
64 *
65 * We cannot switch off the MMU on PPC44x.
66 * So we:
67 * 1) Invalidate all the mappings except the one we are running from.
68 * 2) Create a tmp mapping for our code in the other address space(TS) and
69 *    jump to it. Invalidate the entry we started in.
70 * 3) Create a 1:1 mapping for 0-2GiB in chunks of 256M in original TS.
71 * 4) Jump to the 1:1 mapping in original TS.
72 * 5) Invalidate the tmp mapping.
73 *
74 * - Based on the kexec support code for FSL BookE
75 *
76 */
77
78	/*
79	 * Load the PID with kernel PID (0).
80	 * Also load our MSR_IS and TID to MMUCR for TLB search.
81	 */
82	li	r3, 0
83	mtspr	SPRN_PID, r3
84	mfmsr	r4
85	andi.	r4,r4,MSR_IS@l
86	beq	wmmucr
87	oris	r3,r3,PPC44x_MMUCR_STS@h
88wmmucr:
89	mtspr	SPRN_MMUCR,r3
90	sync
91
92	/*
93	 * Invalidate all the TLB entries except the current entry
94	 * where we are running from
95	 */
96	bcl	20,31,$+4			/* Find our address */
970:	mflr	r5				/* Make it accessible */
98	tlbsx	r23,0,r5			/* Find entry we are in */
99	li	r4,0				/* Start at TLB entry 0 */
100	li	r3,0				/* Set PAGEID inval value */
1011:	cmpw	r23,r4				/* Is this our entry? */
102	beq	skip				/* If so, skip the inval */
103	tlbwe	r3,r4,PPC44x_TLB_PAGEID		/* If not, inval the entry */
104skip:
105	addi	r4,r4,1				/* Increment */
106	cmpwi	r4,64				/* Are we done?	*/
107	bne	1b				/* If not, repeat */
108	isync
109
110	/* Create a temp mapping and jump to it */
111	andi.	r6, r23, 1		/* Find the index to use */
112	addi	r24, r6, 1		/* r24 will contain 1 or 2 */
113
114	mfmsr	r9			/* get the MSR */
115	rlwinm	r5, r9, 27, 31, 31	/* Extract the MSR[IS] */
116	xori	r7, r5, 1		/* Use the other address space */
117
118	/* Read the current mapping entries */
119	tlbre	r3, r23, PPC44x_TLB_PAGEID
120	tlbre	r4, r23, PPC44x_TLB_XLAT
121	tlbre	r5, r23, PPC44x_TLB_ATTRIB
122
123	/* Save our current XLAT entry */
124	mr	r25, r4
125
126	/* Extract the TLB PageSize */
127	li	r10, 1 			/* r10 will hold PageSize */
128	rlwinm	r11, r3, 0, 24, 27	/* bits 24-27 */
129
130	/* XXX: As of now we use 256M, 4K pages */
131	cmpwi	r11, PPC44x_TLB_256M
132	bne	tlb_4k
133	rotlwi	r10, r10, 28		/* r10 = 256M */
134	b	write_out
135tlb_4k:
136	cmpwi	r11, PPC44x_TLB_4K
137	bne	default
138	rotlwi	r10, r10, 12		/* r10 = 4K */
139	b	write_out
140default:
141	rotlwi	r10, r10, 10		/* r10 = 1K */
142
143write_out:
144	/*
145	 * Write out the tmp 1:1 mapping for this code in other address space
146	 * Fixup  EPN = RPN , TS=other address space
147	 */
148	insrwi	r3, r7, 1, 23		/* Bit 23 is TS for PAGEID field */
149
150	/* Write out the tmp mapping entries */
151	tlbwe	r3, r24, PPC44x_TLB_PAGEID
152	tlbwe	r4, r24, PPC44x_TLB_XLAT
153	tlbwe	r5, r24, PPC44x_TLB_ATTRIB
154
155	subi	r11, r10, 1		/* PageOffset Mask = PageSize - 1 */
156	not	r10, r11		/* Mask for PageNum */
157
158	/* Switch to other address space in MSR */
159	insrwi	r9, r7, 1, 26		/* Set MSR[IS] = r7 */
160
161	bcl	20,31,$+4
1621:	mflr	r8
163	addi	r8, r8, (2f-1b)		/* Find the target offset */
164
165	/* Jump to the tmp mapping */
166	mtspr	SPRN_SRR0, r8
167	mtspr	SPRN_SRR1, r9
168	rfi
169
1702:
171	/* Invalidate the entry we were executing from */
172	li	r3, 0
173	tlbwe	r3, r23, PPC44x_TLB_PAGEID
174
175	/* attribute fields. rwx for SUPERVISOR mode */
176	li	r5, 0
177	ori	r5, r5, (PPC44x_TLB_SW | PPC44x_TLB_SR | PPC44x_TLB_SX | PPC44x_TLB_G)
178
179	/* Create 1:1 mapping in 256M pages */
180	xori	r7, r7, 1			/* Revert back to Original TS */
181
182	li	r8, 0				/* PageNumber */
183	li	r6, 3				/* TLB Index, start at 3  */
184
185next_tlb:
186	rotlwi	r3, r8, 28			/* Create EPN (bits 0-3) */
187	mr	r4, r3				/* RPN = EPN  */
188	ori	r3, r3, (PPC44x_TLB_VALID | PPC44x_TLB_256M) /* SIZE = 256M, Valid */
189	insrwi	r3, r7, 1, 23			/* Set TS from r7 */
190
191	tlbwe	r3, r6, PPC44x_TLB_PAGEID	/* PageID field : EPN, V, SIZE */
192	tlbwe	r4, r6, PPC44x_TLB_XLAT		/* Address translation : RPN   */
193	tlbwe	r5, r6, PPC44x_TLB_ATTRIB	/* Attributes */
194
195	addi	r8, r8, 1			/* Increment PN */
196	addi	r6, r6, 1			/* Increment TLB Index */
197	cmpwi	r8, 8				/* Are we done ? */
198	bne	next_tlb
199	isync
200
201	/* Jump to the new mapping 1:1 */
202	li	r9,0
203	insrwi	r9, r7, 1, 26			/* Set MSR[IS] = r7 */
204
205	bcl	20,31,$+4
2061:	mflr	r8
207	and	r8, r8, r11			/* Get our offset within page */
208	addi	r8, r8, (2f-1b)
209
210	and	r5, r25, r10			/* Get our target PageNum */
211	or	r8, r8, r5			/* Target jump address */
212
213	mtspr	SPRN_SRR0, r8
214	mtspr	SPRN_SRR1, r9
215	rfi
2162:
217	/* Invalidate the tmp entry we used */
218	li	r3, 0
219	tlbwe	r3, r24, PPC44x_TLB_PAGEID
220	sync
221	b	ppc44x_map_done
222
223#ifdef CONFIG_PPC_47x
224
225	/* 1:1 mapping for 47x */
226
227setup_map_47x:
228
229	/*
230	 * Load the kernel pid (0) to PID and also to MMUCR[TID].
231	 * Also set the MSR IS->MMUCR STS
232	 */
233	li	r3, 0
234	mtspr	SPRN_PID, r3			/* Set PID */
235	mfmsr	r4				/* Get MSR */
236	andi.	r4, r4, MSR_IS@l		/* TS=1? */
237	beq	1f				/* If not, leave STS=0 */
238	oris	r3, r3, PPC47x_MMUCR_STS@h	/* Set STS=1 */
2391:	mtspr	SPRN_MMUCR, r3			/* Put MMUCR */
240	sync
241
242	/* Find the entry we are running from */
243	bcl	20,31,$+4
2442:	mflr	r23
245	tlbsx	r23, 0, r23
246	tlbre	r24, r23, 0			/* TLB Word 0 */
247	tlbre	r25, r23, 1			/* TLB Word 1 */
248	tlbre	r26, r23, 2			/* TLB Word 2 */
249
250
251	/*
252	 * Invalidates all the tlb entries by writing to 256 RPNs(r4)
253	 * of 4k page size in all  4 ways (0-3 in r3).
254	 * This would invalidate the entire UTLB including the one we are
255	 * running from. However the shadow TLB entries would help us
256	 * to continue the execution, until we flush them (rfi/isync).
257	 */
258	addis	r3, 0, 0x8000			/* specify the way */
259	addi	r4, 0, 0			/* TLB Word0 = (EPN=0, VALID = 0) */
260	addi	r5, 0, 0
261	b	clear_utlb_entry
262
263	/* Align the loop to speed things up. from head_44x.S */
264	.align	6
265
266clear_utlb_entry:
267
268	tlbwe	r4, r3, 0
269	tlbwe	r5, r3, 1
270	tlbwe	r5, r3, 2
271	addis	r3, r3, 0x2000			/* Increment the way */
272	cmpwi	r3, 0
273	bne	clear_utlb_entry
274	addis	r3, 0, 0x8000
275	addis	r4, r4, 0x100			/* Increment the EPN */
276	cmpwi	r4, 0
277	bne	clear_utlb_entry
278
279	/* Create the entries in the other address space */
280	mfmsr	r5
281	rlwinm	r7, r5, 27, 31, 31		/* Get the TS (Bit 26) from MSR */
282	xori	r7, r7, 1			/* r7 = !TS */
283
284	insrwi	r24, r7, 1, 21			/* Change the TS in the saved TLB word 0 */
285
286	/*
287	 * write out the TLB entries for the tmp mapping
288	 * Use way '0' so that we could easily invalidate it later.
289	 */
290	lis	r3, 0x8000			/* Way '0' */
291
292	tlbwe	r24, r3, 0
293	tlbwe	r25, r3, 1
294	tlbwe	r26, r3, 2
295
296	/* Update the msr to the new TS */
297	insrwi	r5, r7, 1, 26
298
299	bcl	20,31,$+4
3001:	mflr	r6
301	addi	r6, r6, (2f-1b)
302
303	mtspr	SPRN_SRR0, r6
304	mtspr	SPRN_SRR1, r5
305	rfi
306
307	/*
308	 * Now we are in the tmp address space.
309	 * Create a 1:1 mapping for 0-2GiB in the original TS.
310	 */
3112:
312	li	r3, 0
313	li	r4, 0				/* TLB Word 0 */
314	li	r5, 0				/* TLB Word 1 */
315	li	r6, 0
316	ori	r6, r6, PPC47x_TLB2_S_RWX	/* TLB word 2 */
317
318	li	r8, 0				/* PageIndex */
319
320	xori	r7, r7, 1			/* revert back to original TS */
321
322write_utlb:
323	rotlwi	r5, r8, 28			/* RPN = PageIndex * 256M */
324						/* ERPN = 0 as we don't use memory above 2G */
325
326	mr	r4, r5				/* EPN = RPN */
327	ori	r4, r4, (PPC47x_TLB0_VALID | PPC47x_TLB0_256M)
328	insrwi	r4, r7, 1, 21			/* Insert the TS to Word 0 */
329
330	tlbwe	r4, r3, 0			/* Write out the entries */
331	tlbwe	r5, r3, 1
332	tlbwe	r6, r3, 2
333	addi	r8, r8, 1
334	cmpwi	r8, 8				/* Have we completed ? */
335	bne	write_utlb
336
337	/* make sure we complete the TLB write up */
338	isync
339
340	/*
341	 * Prepare to jump to the 1:1 mapping.
342	 * 1) Extract page size of the tmp mapping
343	 *    DSIZ = TLB_Word0[22:27]
344	 * 2) Calculate the physical address of the address
345	 *    to jump to.
346	 */
347	rlwinm	r10, r24, 0, 22, 27
348
349	cmpwi	r10, PPC47x_TLB0_4K
350	bne	0f
351	li	r10, 0x1000			/* r10 = 4k */
352	bl	1f
353
3540:
355	/* Defaults to 256M */
356	lis	r10, 0x1000
357
358	bcl	20,31,$+4
3591:	mflr	r4
360	addi	r4, r4, (2f-1b)			/* virtual address  of 2f */
361
362	subi	r11, r10, 1			/* offsetmask = Pagesize - 1 */
363	not	r10, r11			/* Pagemask = ~(offsetmask) */
364
365	and	r5, r25, r10			/* Physical page */
366	and	r6, r4, r11			/* offset within the current page */
367
368	or	r5, r5, r6			/* Physical address for 2f */
369
370	/* Switch the TS in MSR to the original one */
371	mfmsr	r8
372	insrwi	r8, r7, 1, 26
373
374	mtspr	SPRN_SRR1, r8
375	mtspr	SPRN_SRR0, r5
376	rfi
377
3782:
379	/* Invalidate the tmp mapping */
380	lis	r3, 0x8000			/* Way '0' */
381
382	clrrwi	r24, r24, 12			/* Clear the valid bit */
383	tlbwe	r24, r3, 0
384	tlbwe	r25, r3, 1
385	tlbwe	r26, r3, 2
386
387	/* Make sure we complete the TLB write and flush the shadow TLB */
388	isync
389
390#endif
391
392ppc44x_map_done:
393
394
395	/* Restore the parameters */
396	mr	r3, r29
397	mr	r4, r30
398	mr	r5, r31
399
400	li	r0, 0
401#else
402	li	r0, 0
403
404	/*
405	 * Set Machine Status Register to a known status,
406	 * switch the MMU off and jump to 1: in a single step.
407	 */
408
409	mr	r8, r0
410	ori     r8, r8, MSR_RI|MSR_ME
411	mtspr	SPRN_SRR1, r8
412	addi	r8, r4, 1f - relocate_new_kernel
413	mtspr	SPRN_SRR0, r8
414	sync
415	rfi
416
4171:
418#endif
419	/* from this point address translation is turned off */
420	/* and interrupts are disabled */
421
422	/* set a new stack at the bottom of our page... */
423	/* (not really needed now) */
424	addi	r1, r4, KEXEC_CONTROL_PAGE_SIZE - 8 /* for LR Save+Back Chain */
425	stw	r0, 0(r1)
426
427	/* Do the copies */
428	li	r6, 0 /* checksum */
429	mr	r0, r3
430	b	1f
431
4320:	/* top, read another word for the indirection page */
433	lwzu	r0, 4(r3)
434
4351:
436	/* is it a destination page? (r8) */
437	rlwinm.	r7, r0, 0, 31, 31 /* IND_DESTINATION (1<<0) */
438	beq	2f
439
440	rlwinm	r8, r0, 0, 0, 19 /* clear kexec flags, page align */
441	b	0b
442
4432:	/* is it an indirection page? (r3) */
444	rlwinm.	r7, r0, 0, 30, 30 /* IND_INDIRECTION (1<<1) */
445	beq	2f
446
447	rlwinm	r3, r0, 0, 0, 19 /* clear kexec flags, page align */
448	subi	r3, r3, 4
449	b	0b
450
4512:	/* are we done? */
452	rlwinm.	r7, r0, 0, 29, 29 /* IND_DONE (1<<2) */
453	beq	2f
454	b	3f
455
4562:	/* is it a source page? (r9) */
457	rlwinm.	r7, r0, 0, 28, 28 /* IND_SOURCE (1<<3) */
458	beq	0b
459
460	rlwinm	r9, r0, 0, 0, 19 /* clear kexec flags, page align */
461
462	li	r7, PAGE_SIZE / 4
463	mtctr   r7
464	subi    r9, r9, 4
465	subi    r8, r8, 4
4669:
467	lwzu    r0, 4(r9)  /* do the copy */
468	xor	r6, r6, r0
469	stwu    r0, 4(r8)
470	dcbst	0, r8
471	sync
472	icbi	0, r8
473	bdnz    9b
474
475	addi    r9, r9, 4
476	addi    r8, r8, 4
477	b	0b
478
4793:
480
481	/* To be certain of avoiding problems with self-modifying code
482	 * execute a serializing instruction here.
483	 */
484	isync
485	sync
486
487	mfspr	r3, SPRN_PIR /* current core we are running on */
488	mr	r4, r5 /* load physical address of chunk called */
489
490	/* jump to the entry point, usually the setup routine */
491	mtlr	r5
492	blrl
493
4941:	b	1b
495
496relocate_new_kernel_end:
497
498	.globl relocate_new_kernel_size
499relocate_new_kernel_size:
500	.long relocate_new_kernel_end - relocate_new_kernel
501