xref: /openbmc/linux/arch/powerpc/kernel/misc_64.S (revision 234489ac) 
1/* SPDX-License-Identifier: GPL-2.0-or-later */
2/*
3 * This file contains miscellaneous low-level functions.
4 *    Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
5 *
6 * Largely rewritten by Cort Dougan (cort@cs.nmt.edu)
7 * and Paul Mackerras.
8 * Adapted for iSeries by Mike Corrigan (mikejc@us.ibm.com)
9 * PPC64 updates by Dave Engebretsen (engebret@us.ibm.com)
10 */
11
12#include <linux/linkage.h>
13#include <linux/sys.h>
14#include <asm/unistd.h>
15#include <asm/errno.h>
16#include <asm/processor.h>
17#include <asm/page.h>
18#include <asm/cache.h>
19#include <asm/ppc_asm.h>
20#include <asm/asm-offsets.h>
21#include <asm/cputable.h>
22#include <asm/thread_info.h>
23#include <asm/kexec.h>
24#include <asm/ptrace.h>
25#include <asm/mmu.h>
26#include <asm/export.h>
27#include <asm/feature-fixups.h>
28
29	.text
30
31_GLOBAL(__bswapdi2)
32EXPORT_SYMBOL(__bswapdi2)
33	srdi	r8,r3,32
34	rlwinm	r7,r3,8,0xffffffff
35	rlwimi	r7,r3,24,0,7
36	rlwinm	r9,r8,8,0xffffffff
37	rlwimi	r7,r3,24,16,23
38	rlwimi	r9,r8,24,0,7
39	rlwimi	r9,r8,24,16,23
40	sldi	r7,r7,32
41	or	r3,r7,r9
42	blr
43
44
45#ifdef CONFIG_PPC_EARLY_DEBUG_BOOTX
46_GLOBAL(rmci_on)
47	sync
48	isync
49	li	r3,0x100
50	rldicl	r3,r3,32,0
51	mfspr	r5,SPRN_HID4
52	or	r5,r5,r3
53	sync
54	mtspr	SPRN_HID4,r5
55	isync
56	slbia
57	isync
58	sync
59	blr
60
61_GLOBAL(rmci_off)
62	sync
63	isync
64	li	r3,0x100
65	rldicl	r3,r3,32,0
66	mfspr	r5,SPRN_HID4
67	andc	r5,r5,r3
68	sync
69	mtspr	SPRN_HID4,r5
70	isync
71	slbia
72	isync
73	sync
74	blr
75#endif /* CONFIG_PPC_EARLY_DEBUG_BOOTX */
76
77#if defined(CONFIG_PPC_PMAC) || defined(CONFIG_PPC_MAPLE)
78
79/*
80 * Do an IO access in real mode
81 */
82_GLOBAL(real_readb)
83	mfmsr	r7
84	ori	r0,r7,MSR_DR
85	xori	r0,r0,MSR_DR
86	sync
87	mtmsrd	r0
88	sync
89	isync
90	mfspr	r6,SPRN_HID4
91	rldicl	r5,r6,32,0
92	ori	r5,r5,0x100
93	rldicl	r5,r5,32,0
94	sync
95	mtspr	SPRN_HID4,r5
96	isync
97	slbia
98	isync
99	lbz	r3,0(r3)
100	sync
101	mtspr	SPRN_HID4,r6
102	isync
103	slbia
104	isync
105	mtmsrd	r7
106	sync
107	isync
108	blr
109
110	/*
111 * Do an IO access in real mode
112 */
113_GLOBAL(real_writeb)
114	mfmsr	r7
115	ori	r0,r7,MSR_DR
116	xori	r0,r0,MSR_DR
117	sync
118	mtmsrd	r0
119	sync
120	isync
121	mfspr	r6,SPRN_HID4
122	rldicl	r5,r6,32,0
123	ori	r5,r5,0x100
124	rldicl	r5,r5,32,0
125	sync
126	mtspr	SPRN_HID4,r5
127	isync
128	slbia
129	isync
130	stb	r3,0(r4)
131	sync
132	mtspr	SPRN_HID4,r6
133	isync
134	slbia
135	isync
136	mtmsrd	r7
137	sync
138	isync
139	blr
140#endif /* defined(CONFIG_PPC_PMAC) || defined(CONFIG_PPC_MAPLE) */
141
142#ifdef CONFIG_PPC_PASEMI
143
144_GLOBAL(real_205_readb)
145	mfmsr	r7
146	ori	r0,r7,MSR_DR
147	xori	r0,r0,MSR_DR
148	sync
149	mtmsrd	r0
150	sync
151	isync
152	LBZCIX(R3,R0,R3)
153	isync
154	mtmsrd	r7
155	sync
156	isync
157	blr
158
159_GLOBAL(real_205_writeb)
160	mfmsr	r7
161	ori	r0,r7,MSR_DR
162	xori	r0,r0,MSR_DR
163	sync
164	mtmsrd	r0
165	sync
166	isync
167	STBCIX(R3,R0,R4)
168	isync
169	mtmsrd	r7
170	sync
171	isync
172	blr
173
174#endif /* CONFIG_PPC_PASEMI */
175
176
177#if defined(CONFIG_CPU_FREQ_PMAC64) || defined(CONFIG_CPU_FREQ_MAPLE)
178/*
179 * SCOM access functions for 970 (FX only for now)
180 *
181 * unsigned long scom970_read(unsigned int address);
182 * void scom970_write(unsigned int address, unsigned long value);
183 *
184 * The address passed in is the 24 bits register address. This code
185 * is 970 specific and will not check the status bits, so you should
186 * know what you are doing.
187 */
188_GLOBAL(scom970_read)
189	/* interrupts off */
190	mfmsr	r4
191	ori	r0,r4,MSR_EE
192	xori	r0,r0,MSR_EE
193	mtmsrd	r0,1
194
195	/* rotate 24 bits SCOM address 8 bits left and mask out it's low 8 bits
196	 * (including parity). On current CPUs they must be 0'd,
197	 * and finally or in RW bit
198	 */
199	rlwinm	r3,r3,8,0,15
200	ori	r3,r3,0x8000
201
202	/* do the actual scom read */
203	sync
204	mtspr	SPRN_SCOMC,r3
205	isync
206	mfspr	r3,SPRN_SCOMD
207	isync
208	mfspr	r0,SPRN_SCOMC
209	isync
210
211	/* XXX:	fixup result on some buggy 970's (ouch ! we lost a bit, bah
212	 * that's the best we can do). Not implemented yet as we don't use
213	 * the scom on any of the bogus CPUs yet, but may have to be done
214	 * ultimately
215	 */
216
217	/* restore interrupts */
218	mtmsrd	r4,1
219	blr
220
221
222_GLOBAL(scom970_write)
223	/* interrupts off */
224	mfmsr	r5
225	ori	r0,r5,MSR_EE
226	xori	r0,r0,MSR_EE
227	mtmsrd	r0,1
228
229	/* rotate 24 bits SCOM address 8 bits left and mask out it's low 8 bits
230	 * (including parity). On current CPUs they must be 0'd.
231	 */
232
233	rlwinm	r3,r3,8,0,15
234
235	sync
236	mtspr	SPRN_SCOMD,r4      /* write data */
237	isync
238	mtspr	SPRN_SCOMC,r3      /* write command */
239	isync
240	mfspr	3,SPRN_SCOMC
241	isync
242
243	/* restore interrupts */
244	mtmsrd	r5,1
245	blr
246#endif /* CONFIG_CPU_FREQ_PMAC64 || CONFIG_CPU_FREQ_MAPLE */
247
248/* kexec_wait(phys_cpu)
249 *
250 * wait for the flag to change, indicating this kernel is going away but
251 * the slave code for the next one is at addresses 0 to 100.
252 *
253 * This is used by all slaves, even those that did not find a matching
254 * paca in the secondary startup code.
255 *
256 * Physical (hardware) cpu id should be in r3.
257 */
258_GLOBAL(kexec_wait)
259	bcl	20,31,$+4
2601:	mflr	r5
261	addi	r5,r5,kexec_flag-1b
262
26399:	HMT_LOW
264#ifdef CONFIG_KEXEC_CORE	/* use no memory without kexec */
265	lwz	r4,0(r5)
266	cmpwi	0,r4,0
267	beq	99b
268#ifdef CONFIG_PPC_BOOK3S_64
269	li	r10,0x60
270	mfmsr	r11
271	clrrdi	r11,r11,1	/* Clear MSR_LE */
272	mtsrr0	r10
273	mtsrr1	r11
274	rfid
275#else
276	/* Create TLB entry in book3e_secondary_core_init */
277	li	r4,0
278	ba	0x60
279#endif
280#endif
281
282/* this can be in text because we won't change it until we are
283 * running in real anyways
284 */
285kexec_flag:
286	.long	0
287
288
289#ifdef CONFIG_KEXEC_CORE
290#ifdef CONFIG_PPC_BOOK3E_64
291/*
292 * BOOK3E has no real MMU mode, so we have to setup the initial TLB
293 * for a core to identity map v:0 to p:0.  This current implementation
294 * assumes that 1G is enough for kexec.
295 */
296kexec_create_tlb:
297	/*
298	 * Invalidate all non-IPROT TLB entries to avoid any TLB conflict.
299	 * IPROT TLB entries should be >= PAGE_OFFSET and thus not conflict.
300	 */
301	PPC_TLBILX_ALL(0,R0)
302	sync
303	isync
304
305	mfspr	r10,SPRN_TLB1CFG
306	andi.	r10,r10,TLBnCFG_N_ENTRY	/* Extract # entries */
307	subi	r10,r10,1	/* Last entry: no conflict with kernel text */
308	lis	r9,MAS0_TLBSEL(1)@h
309	rlwimi	r9,r10,16,4,15		/* Setup MAS0 = TLBSEL | ESEL(r9) */
310
311/* Set up a temp identity mapping v:0 to p:0 and return to it. */
312	mtspr	SPRN_MAS0,r9
313
314	lis	r9,(MAS1_VALID|MAS1_IPROT)@h
315	ori	r9,r9,(MAS1_TSIZE(BOOK3E_PAGESZ_1GB))@l
316	mtspr	SPRN_MAS1,r9
317
318	LOAD_REG_IMMEDIATE(r9, 0x0 | MAS2_M_IF_NEEDED)
319	mtspr	SPRN_MAS2,r9
320
321	LOAD_REG_IMMEDIATE(r9, 0x0 | MAS3_SR | MAS3_SW | MAS3_SX)
322	mtspr	SPRN_MAS3,r9
323	li	r9,0
324	mtspr	SPRN_MAS7,r9
325
326	tlbwe
327	isync
328	blr
329#endif
330
331/* kexec_smp_wait(void)
332 *
333 * call with interrupts off
334 * note: this is a terminal routine, it does not save lr
335 *
336 * get phys id from paca
337 * switch to real mode
338 * mark the paca as no longer used
339 * join other cpus in kexec_wait(phys_id)
340 */
341_GLOBAL(kexec_smp_wait)
342	lhz	r3,PACAHWCPUID(r13)
343	bl	real_mode
344
345	li	r4,KEXEC_STATE_REAL_MODE
346	stb	r4,PACAKEXECSTATE(r13)
347
348	b	kexec_wait
349
350/*
351 * switch to real mode (turn mmu off)
352 * we use the early kernel trick that the hardware ignores bits
353 * 0 and 1 (big endian) of the effective address in real mode
354 *
355 * don't overwrite r3 here, it is live for kexec_wait above.
356 */
357SYM_FUNC_START_LOCAL(real_mode)	/* assume normal blr return */
358#ifdef CONFIG_PPC_BOOK3E_64
359	/* Create an identity mapping. */
360	b	kexec_create_tlb
361#else
3621:	li	r9,MSR_RI
363	li	r10,MSR_DR|MSR_IR
364	mflr	r11		/* return address to SRR0 */
365	mfmsr	r12
366	andc	r9,r12,r9
367	andc	r10,r12,r10
368
369	mtmsrd	r9,1
370	mtspr	SPRN_SRR1,r10
371	mtspr	SPRN_SRR0,r11
372	rfid
373#endif
374SYM_FUNC_END(real_mode)
375
376/*
377 * kexec_sequence(newstack, start, image, control, clear_all(),
378	          copy_with_mmu_off)
379 *
380 * does the grungy work with stack switching and real mode switches
381 * also does simple calls to other code
382 */
383
384_GLOBAL(kexec_sequence)
385	mflr	r0
386	std	r0,16(r1)
387
388	/* switch stacks to newstack -- &kexec_stack.stack */
389	stdu	r1,THREAD_SIZE-STACK_FRAME_MIN_SIZE(r3)
390	mr	r1,r3
391
392	li	r0,0
393	std	r0,16(r1)
394
395	/* save regs for local vars on new stack.
396	 * yes, we won't go back, but ...
397	 */
398	std	r31,-8(r1)
399	std	r30,-16(r1)
400	std	r29,-24(r1)
401	std	r28,-32(r1)
402	std	r27,-40(r1)
403	std	r26,-48(r1)
404	std	r25,-56(r1)
405
406	stdu	r1,-STACK_FRAME_MIN_SIZE-64(r1)
407
408	/* save args into preserved regs */
409	mr	r31,r3			/* newstack (both) */
410	mr	r30,r4			/* start (real) */
411	mr	r29,r5			/* image (virt) */
412	mr	r28,r6			/* control, unused */
413	mr	r27,r7			/* clear_all() fn desc */
414	mr	r26,r8			/* copy_with_mmu_off */
415	lhz	r25,PACAHWCPUID(r13)	/* get our phys cpu from paca */
416
417	/* disable interrupts, we are overwriting kernel data next */
418#ifdef CONFIG_PPC_BOOK3E_64
419	wrteei	0
420#else
421	mfmsr	r3
422	rlwinm	r3,r3,0,17,15
423	mtmsrd	r3,1
424#endif
425
426	/* We need to turn the MMU off unless we are in hash mode
427	 * under a hypervisor
428	 */
429	cmpdi	r26,0
430	beq	1f
431	bl	real_mode
4321:
433	/* copy dest pages, flush whole dest image */
434	mr	r3,r29
435	bl	CFUNC(kexec_copy_flush)	/* (image) */
436
437	/* turn off mmu now if not done earlier */
438	cmpdi	r26,0
439	bne	1f
440	bl	real_mode
441
442	/* copy  0x100 bytes starting at start to 0 */
4431:	li	r3,0
444	mr	r4,r30		/* start, aka phys mem offset */
445	li	r5,0x100
446	li	r6,0
447	bl	copy_and_flush	/* (dest, src, copy limit, start offset) */
4481:	/* assume normal blr return */
449
450	/* release other cpus to the new kernel secondary start at 0x60 */
451	mflr	r5
452	li	r6,1
453	stw	r6,kexec_flag-1b(5)
454
455	cmpdi	r27,0
456	beq	1f
457
458	/* clear out hardware hash page table and tlb */
459#ifdef CONFIG_PPC64_ELF_ABI_V1
460	ld	r12,0(r27)		/* deref function descriptor */
461#else
462	mr	r12,r27
463#endif
464	mtctr	r12
465	bctrl				/* mmu_hash_ops.hpte_clear_all(void); */
466
467/*
468 *   kexec image calling is:
469 *      the first 0x100 bytes of the entry point are copied to 0
470 *
471 *      all slaves branch to slave = 0x60 (absolute)
472 *              slave(phys_cpu_id);
473 *
474 *      master goes to start = entry point
475 *              start(phys_cpu_id, start, 0);
476 *
477 *
478 *   a wrapper is needed to call existing kernels, here is an approximate
479 *   description of one method:
480 *
481 * v2: (2.6.10)
482 *   start will be near the boot_block (maybe 0x100 bytes before it?)
483 *   it will have a 0x60, which will b to boot_block, where it will wait
484 *   and 0 will store phys into struct boot-block and load r3 from there,
485 *   copy kernel 0-0x100 and tell slaves to back down to 0x60 again
486 *
487 * v1: (2.6.9)
488 *    boot block will have all cpus scanning device tree to see if they
489 *    are the boot cpu ?????
490 *    other device tree differences (prop sizes, va vs pa, etc)...
491 */
4921:	mr	r3,r25	# my phys cpu
493	mr	r4,r30	# start, aka phys mem offset
494	mtlr	4
495	li	r5,0
496	blr	/* image->start(physid, image->start, 0); */
497#endif /* CONFIG_KEXEC_CORE */
498