xref: /freebsd/sys/arm64/arm64/locore.S (revision 1fb62fb074788ca4713551be09d6569966a3abee)
1/*-
2 * Copyright (c) 2012-2014 Andrew Turner
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 *    notice, this list of conditions and the following disclaimer in the
12 *    documentation and/or other materials provided with the distribution.
13 *
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24 * SUCH DAMAGE.
25 *
26 * $FreeBSD$
27 */
28
29#include "assym.s"
30#include "opt_kstack_pages.h"
31#include <sys/syscall.h>
32#include <machine/asm.h>
33#include <machine/armreg.h>
34#include <machine/hypervisor.h>
35#include <machine/param.h>
36#include <machine/pte.h>
37#include <machine/vmparam.h>
38
39#define	VIRT_BITS	48
40#define	DMAP_TABLES	((DMAP_MAX_ADDRESS - DMAP_MIN_ADDRESS) >> L0_SHIFT)
41
42	.globl	kernbase
43	.set	kernbase, KERNBASE
44
45#define	DEVICE_MEM	0
46#define	NORMAL_UNCACHED	1
47#define	NORMAL_MEM	2
48
49/*
50 * We assume:
51 *  MMU      on with an identity map, or off
52 *  D-Cache: off
53 *  I-Cache: on or off
54 *  We are loaded at a 2MiB aligned address
55 */
56
57	.text
58	.globl _start
59_start:
60	/* Drop to EL1 */
61	bl	drop_to_el1
62
63	/*
64	 * Disable the MMU. We may have entered the kernel with it on and
65	 * will need to update the tables later. If this has been set up
66	 * with anything other than a VA == PA map then this will fail,
67	 * but in this case the code to find where we are running from
68	 * would have also failed.
69	 */
70	dsb	sy
71	mrs	x2, sctlr_el1
72	bic	x2, x2, SCTLR_M
73	msr	sctlr_el1, x2
74	isb
75
76	/* Set the context id */
77	msr	contextidr_el1, xzr
78
79	/* Get the virt -> phys offset */
80	bl	get_virt_delta
81
82	/*
83	 * At this point:
84	 * x29 = PA - VA
85	 * x28 = Our physical load address
86	 */
87
88	/* Create the page tables */
89	bl	create_pagetables
90
91	/*
92	 * At this point:
93	 * x27 = TTBR0 table
94	 * x26 = Kernel L1 table
95	 * x24 = TTBR1 table
96	 */
97
98	/* Enable the mmu */
99	bl	start_mmu
100
101	/* Jump to the virtual address space */
102	ldr	x15, .Lvirtdone
103	br	x15
104
105virtdone:
106	/* Set up the stack */
107	adr	x25, initstack_end
108	mov	sp, x25
109	sub	sp, sp, #PCB_SIZE
110
111	/* Zero the BSS */
112	ldr	x15, .Lbss
113	ldr	x14, .Lend
1141:
115	str	xzr, [x15], #8
116	cmp	x15, x14
117	b.lo	1b
118
119	/* Backup the module pointer */
120	mov	x1, x0
121
122	/* Make the page table base a virtual address */
123	sub	x26, x26, x29
124	sub	x24, x24, x29
125
126	sub	sp, sp, #(64 * 4)
127	mov	x0, sp
128
129	/* Degate the delda so it is VA -> PA */
130	neg	x29, x29
131
132	str	x1,  [x0]	/* modulep */
133	str	x26, [x0, 8]	/* kern_l1pt */
134	str	x29, [x0, 16]	/* kern_delta */
135	str	x25, [x0, 24]	/* kern_stack */
136	str	x24, [x0, 32]	/* kern_l0pt */
137
138	/* trace back starts here */
139	mov	fp, #0
140	/* Branch to C code */
141	bl	initarm
142	bl	mi_startup
143
144	/* We should not get here */
145	brk	0
146
147	.align 3
148.Lvirtdone:
149	.quad	virtdone
150.Lbss:
151	.quad	__bss_start
152.Lend:
153	.quad	_end
154
155#ifdef SMP
156/*
157 * mpentry(unsigned long)
158 *
159 * Called by a core when it is being brought online.
160 * The data in x0 is passed straight to init_secondary.
161 */
162ENTRY(mpentry)
163	/* Disable interrupts */
164	msr	daifset, #2
165
166	/* Drop to EL1 */
167	bl	drop_to_el1
168
169	/* Set the context id */
170	msr	contextidr_el1, x1
171
172	/* Load the kernel page table */
173	adr	x24, pagetable_l0_ttbr1
174	/* Load the identity page table */
175	adr	x27, pagetable_l0_ttbr0
176
177	/* Enable the mmu */
178	bl	start_mmu
179
180	/* Jump to the virtual address space */
181	ldr	x15, =mp_virtdone
182	br	x15
183
184mp_virtdone:
185	ldr	x4, =secondary_stacks
186	mov	x5, #(PAGE_SIZE * KSTACK_PAGES)
187	mul	x5, x0, x5
188	add	sp, x4, x5
189
190	b	init_secondary
191END(mpentry)
192#endif
193
194/*
195 * If we are started in EL2, configure the required hypervisor
196 * registers and drop to EL1.
197 */
198drop_to_el1:
199	mrs	x1, CurrentEL
200	lsr	x1, x1, #2
201	cmp	x1, #0x2
202	b.eq	1f
203	ret
2041:
205	/* Configure the Hypervisor */
206	mov	x2, #(HCR_RW)
207	msr	hcr_el2, x2
208
209	/* Load the Virtualization Process ID Register */
210	mrs	x2, midr_el1
211	msr	vpidr_el2, x2
212
213	/* Load the Virtualization Multiprocess ID Register */
214	mrs	x2, mpidr_el1
215	msr	vmpidr_el2, x2
216
217	/* Set the bits that need to be 1 in sctlr_el1 */
218	ldr	x2, .Lsctlr_res1
219	msr	sctlr_el1, x2
220
221	/* Don't trap to EL2 for exceptions */
222	mov	x2, #CPTR_RES1
223	msr	cptr_el2, x2
224
225	/* Don't trap to EL2 for CP15 traps */
226	msr	hstr_el2, xzr
227
228	/* Enable access to the physical timers at EL1 */
229	mrs	x2, cnthctl_el2
230	orr	x2, x2, #(CNTHCTL_EL1PCTEN | CNTHCTL_EL1PCEN)
231	msr	cnthctl_el2, x2
232
233	/* Set the counter offset to a known value */
234	msr	cntvoff_el2, xzr
235
236	/* Hypervisor trap functions */
237	adr	x2, hyp_vectors
238	msr	vbar_el2, x2
239
240	mov	x2, #(PSR_F | PSR_I | PSR_A | PSR_D | PSR_M_EL1h)
241	msr	spsr_el2, x2
242
243	/* Configure GICv3 CPU interface */
244	mrs	x2, id_aa64pfr0_el1
245	/* Extract GIC bits from the register */
246	ubfx	x2, x2, #ID_AA64PFR0_GIC_SHIFT, #ID_AA64PFR0_GIC_BITS
247	/* GIC[3:0] == 0001 - GIC CPU interface via special regs. supported */
248	cmp	x2, #(ID_AA64PFR0_GIC_CPUIF_EN >> ID_AA64PFR0_GIC_SHIFT)
249	b.ne	2f
250
251	mrs	x2, icc_sre_el2
252	orr	x2, x2, #ICC_SRE_EL2_EN	/* Enable access from insecure EL1 */
253	orr	x2, x2, #ICC_SRE_EL2_SRE	/* Enable system registers */
254	msr	icc_sre_el2, x2
2552:
256
257	/* Set the address to return to our return address */
258	msr	elr_el2, x30
259	isb
260
261	eret
262
263	.align 3
264.Lsctlr_res1:
265	.quad SCTLR_RES1
266
267#define	VECT_EMPTY	\
268	.align 7;	\
269	1:	b	1b
270
271	.align 11
272hyp_vectors:
273	VECT_EMPTY	/* Synchronous EL2t */
274	VECT_EMPTY	/* IRQ EL2t */
275	VECT_EMPTY	/* FIQ EL2t */
276	VECT_EMPTY	/* Error EL2t */
277
278	VECT_EMPTY	/* Synchronous EL2h */
279	VECT_EMPTY	/* IRQ EL2h */
280	VECT_EMPTY	/* FIQ EL2h */
281	VECT_EMPTY	/* Error EL2h */
282
283	VECT_EMPTY	/* Synchronous 64-bit EL1 */
284	VECT_EMPTY	/* IRQ 64-bit EL1 */
285	VECT_EMPTY	/* FIQ 64-bit EL1 */
286	VECT_EMPTY	/* Error 64-bit EL1 */
287
288	VECT_EMPTY	/* Synchronous 32-bit EL1 */
289	VECT_EMPTY	/* IRQ 32-bit EL1 */
290	VECT_EMPTY	/* FIQ 32-bit EL1 */
291	VECT_EMPTY	/* Error 32-bit EL1 */
292
293/*
294 * Get the delta between the physical address we were loaded to and the
295 * virtual address we expect to run from. This is used when building the
296 * initial page table.
297 */
298get_virt_delta:
299	/* Load the physical address of virt_map */
300	adr	x29, virt_map
301	/* Load the virtual address of virt_map stored in virt_map */
302	ldr	x28, [x29]
303	/* Find PA - VA as PA' = VA' - VA + PA = VA' + (PA - VA) = VA' + x29 */
304	sub	x29, x29, x28
305	/* Find the load address for the kernel */
306	mov	x28, #(KERNBASE)
307	add	x28, x28, x29
308	ret
309
310	.align 3
311virt_map:
312	.quad	virt_map
313
314/*
315 * This builds the page tables containing the identity map, and the kernel
316 * virtual map.
317 *
318 * It relys on:
319 *  We were loaded to an address that is on a 2MiB boundary
320 *  All the memory must not cross a 1GiB boundaty
321 *  x28 contains the physical address we were loaded from
322 *
323 * TODO: This is out of date.
324 *  There are at least 5 pages before that address for the page tables
325 *   The pages used are:
326 *    - The Kernel L2 table
327 *    - The Kernel L1 table
328 *    - The Kernel L0 table             (TTBR1)
329 *    - The identity (PA = VA) L1 table
330 *    - The identity (PA = VA) L0 table (TTBR0)
331 *    - The DMAP L1 tables
332 */
333create_pagetables:
334	/* Save the Link register */
335	mov	x5, x30
336
337	/* Clean the page table */
338	adr	x6, pagetable
339	mov	x26, x6
340	adr	x27, pagetable_end
3411:
342	stp	xzr, xzr, [x6], #16
343	stp	xzr, xzr, [x6], #16
344	stp	xzr, xzr, [x6], #16
345	stp	xzr, xzr, [x6], #16
346	cmp	x6, x27
347	b.lo	1b
348
349	/*
350	 * Build the TTBR1 maps.
351	 */
352
353	/* Find the size of the kernel */
354	mov	x6, #(KERNBASE)
355	ldr	x7, .Lend
356	/* Find the end - begin */
357	sub	x8, x7, x6
358	/* Get the number of l2 pages to allocate, rounded down */
359	lsr	x10, x8, #(L2_SHIFT)
360	/* Add 8 MiB for any rounding above and the module data */
361	add	x10, x10, #4
362
363	/* Create the kernel space L2 table */
364	mov	x6, x26
365	mov	x7, #NORMAL_MEM
366	mov	x8, #(KERNBASE & L2_BLOCK_MASK)
367	mov	x9, x28
368	bl	build_l2_block_pagetable
369
370	/* Move to the l1 table */
371	add	x26, x26, #PAGE_SIZE
372
373	/* Link the l1 -> l2 table */
374	mov	x9, x6
375	mov	x6, x26
376	bl	link_l1_pagetable
377
378	/* Move to the l0 table */
379	add	x24, x26, #PAGE_SIZE
380
381	/* Link the l0 -> l1 table */
382	mov	x9, x6
383	mov	x6, x24
384	mov	x10, #1
385	bl	link_l0_pagetable
386
387	/* Link the DMAP tables */
388	ldr	x8, =DMAP_MIN_ADDRESS
389	adr	x9, pagetable_dmap;
390	mov	x10, #DMAP_TABLES
391	bl	link_l0_pagetable
392
393	/*
394	 * Build the TTBR0 maps.
395	 */
396	add	x27, x24, #PAGE_SIZE
397
398	mov	x6, x27		/* The initial page table */
399#if defined(SOCDEV_PA) && defined(SOCDEV_VA)
400	/* Create a table for the UART */
401	mov	x7, #DEVICE_MEM
402	mov	x8, #(SOCDEV_VA)	/* VA start */
403	mov	x9, #(SOCDEV_PA)	/* PA start */
404	mov	x10, #1
405	bl	build_l1_block_pagetable
406#endif
407
408	/* Create the VA = PA map */
409	mov	x7, #NORMAL_UNCACHED /* Uncached as it's only needed early on */
410	mov	x9, x27
411	mov	x8, x9		/* VA start (== PA start) */
412	mov	x10, #1
413	bl	build_l1_block_pagetable
414
415	/* Move to the l0 table */
416	add	x27, x27, #PAGE_SIZE
417
418	/* Link the l0 -> l1 table */
419	mov	x9, x6
420	mov	x6, x27
421	mov	x10, #1
422	bl	link_l0_pagetable
423
424	/* Restore the Link register */
425	mov	x30, x5
426	ret
427
428/*
429 * Builds an L0 -> L1 table descriptor
430 *
431 * This is a link for a 512GiB block of memory with up to 1GiB regions mapped
432 * within it by build_l1_block_pagetable.
433 *
434 *  x6  = L0 table
435 *  x8  = Virtual Address
436 *  x9  = L1 PA (trashed)
437 *  x10 = Entry count
438 *  x11, x12 and x13 are trashed
439 */
440link_l0_pagetable:
441	/*
442	 * Link an L0 -> L1 table entry.
443	 */
444	/* Find the table index */
445	lsr	x11, x8, #L0_SHIFT
446	and	x11, x11, #L0_ADDR_MASK
447
448	/* Build the L0 block entry */
449	mov	x12, #L0_TABLE
450
451	/* Only use the output address bits */
452	lsr	x9, x9, #PAGE_SHIFT
4531:	orr	x13, x12, x9, lsl #PAGE_SHIFT
454
455	/* Store the entry */
456	str	x13, [x6, x11, lsl #3]
457
458	sub	x10, x10, #1
459	add	x11, x11, #1
460	add	x9, x9, #1
461	cbnz	x10, 1b
462
463	ret
464
465/*
466 * Builds an L1 -> L2 table descriptor
467 *
468 * This is a link for a 1GiB block of memory with up to 2MiB regions mapped
469 * within it by build_l2_block_pagetable.
470 *
471 *  x6  = L1 table
472 *  x8  = Virtual Address
473 *  x9  = L2 PA (trashed)
474 *  x11, x12 and x13 are trashed
475 */
476link_l1_pagetable:
477	/*
478	 * Link an L1 -> L2 table entry.
479	 */
480	/* Find the table index */
481	lsr	x11, x8, #L1_SHIFT
482	and	x11, x11, #Ln_ADDR_MASK
483
484	/* Build the L1 block entry */
485	mov	x12, #L1_TABLE
486
487	/* Only use the output address bits */
488	lsr	x9, x9, #PAGE_SHIFT
489	orr	x13, x12, x9, lsl #PAGE_SHIFT
490
491	/* Store the entry */
492	str	x13, [x6, x11, lsl #3]
493
494	ret
495
496/*
497 * Builds count 1 GiB page table entry
498 *  x6  = L1 table
499 *  x7  = Type (0 = Device, 1 = Normal)
500 *  x8  = VA start
501 *  x9  = PA start (trashed)
502 *  x10 = Entry count
503 *  x11, x12 and x13 are trashed
504 */
505build_l1_block_pagetable:
506	/*
507	 * Build the L1 table entry.
508	 */
509	/* Find the table index */
510	lsr	x11, x8, #L1_SHIFT
511	and	x11, x11, #Ln_ADDR_MASK
512
513	/* Build the L1 block entry */
514	lsl	x12, x7, #2
515	orr	x12, x12, #L1_BLOCK
516	orr	x12, x12, #(ATTR_AF)
517#ifdef SMP
518	orr	x12, x12, ATTR_SH(ATTR_SH_IS)
519#endif
520
521	/* Only use the output address bits */
522	lsr	x9, x9, #L1_SHIFT
523
524	/* Set the physical address for this virtual address */
5251:	orr	x13, x12, x9, lsl #L1_SHIFT
526
527	/* Store the entry */
528	str	x13, [x6, x11, lsl #3]
529
530	sub	x10, x10, #1
531	add	x11, x11, #1
532	add	x9, x9, #1
533	cbnz	x10, 1b
534
535	ret
536
537/*
538 * Builds count 2 MiB page table entry
539 *  x6  = L2 table
540 *  x7  = Type (0 = Device, 1 = Normal)
541 *  x8  = VA start
542 *  x9  = PA start (trashed)
543 *  x10 = Entry count
544 *  x11, x12 and x13 are trashed
545 */
546build_l2_block_pagetable:
547	/*
548	 * Build the L2 table entry.
549	 */
550	/* Find the table index */
551	lsr	x11, x8, #L2_SHIFT
552	and	x11, x11, #Ln_ADDR_MASK
553
554	/* Build the L2 block entry */
555	lsl	x12, x7, #2
556	orr	x12, x12, #L2_BLOCK
557	orr	x12, x12, #(ATTR_AF)
558#ifdef SMP
559	orr	x12, x12, ATTR_SH(ATTR_SH_IS)
560#endif
561
562	/* Only use the output address bits */
563	lsr	x9, x9, #L2_SHIFT
564
565	/* Set the physical address for this virtual address */
5661:	orr	x13, x12, x9, lsl #L2_SHIFT
567
568	/* Store the entry */
569	str	x13, [x6, x11, lsl #3]
570
571	sub	x10, x10, #1
572	add	x11, x11, #1
573	add	x9, x9, #1
574	cbnz	x10, 1b
575
576	ret
577
578start_mmu:
579	dsb	sy
580
581	/* Load the exception vectors */
582	ldr	x2, =exception_vectors
583	msr	vbar_el1, x2
584
585	/* Load ttbr0 and ttbr1 */
586	msr	ttbr0_el1, x27
587	msr	ttbr1_el1, x24
588	isb
589
590	/* Clear the Monitor Debug System control register */
591	msr	mdscr_el1, xzr
592
593	/* Invalidate the TLB */
594	tlbi	vmalle1is
595
596	ldr	x2, mair
597	msr	mair_el1, x2
598
599	/*
600	 * Setup TCR according to PARange bits from ID_AA64MMFR0_EL1.
601	 */
602	ldr	x2, tcr
603	mrs	x3, id_aa64mmfr0_el1
604	bfi	x2, x3, #32, #3
605	msr	tcr_el1, x2
606
607	/* Setup SCTLR */
608	ldr	x2, sctlr_set
609	ldr	x3, sctlr_clear
610	mrs	x1, sctlr_el1
611	bic	x1, x1, x3	/* Clear the required bits */
612	orr	x1, x1, x2	/* Set the required bits */
613	msr	sctlr_el1, x1
614	isb
615
616	ret
617
618	.align 3
619mair:
620	.quad	MAIR_ATTR(MAIR_DEVICE_nGnRnE, 0) |	\
621		MAIR_ATTR(MAIR_NORMAL_NC, 1) |		\
622		MAIR_ATTR(MAIR_NORMAL_WB, 2) |		\
623		MAIR_ATTR(MAIR_NORMAL_WT, 3)
624tcr:
625	.quad (TCR_TxSZ(64 - VIRT_BITS) | TCR_ASID_16 | TCR_TG1_4K | \
626	    TCR_CACHE_ATTRS | TCR_SMP_ATTRS)
627sctlr_set:
628	/* Bits to set */
629	.quad (SCTLR_UCI | SCTLR_nTWE | SCTLR_nTWI | SCTLR_UCT | SCTLR_DZE | \
630	    SCTLR_I | SCTLR_SED | SCTLR_SA0 | SCTLR_SA | SCTLR_C | SCTLR_M)
631sctlr_clear:
632	/* Bits to clear */
633	.quad (SCTLR_EE | SCTLR_EOE | SCTLR_WXN | SCTLR_UMA | SCTLR_ITD | \
634	    SCTLR_THEE | SCTLR_CP15BEN | SCTLR_A)
635
636	.globl abort
637abort:
638	b abort
639
640	//.section .init_pagetable
641	.align 12 /* 4KiB aligned */
642	/*
643	 * 3 initial tables (in the following order):
644	 *           L2 for kernel (High addresses)
645	 *           L1 for kernel
646	 *           L1 for user   (Low addresses)
647	 */
648pagetable:
649	.space	PAGE_SIZE
650pagetable_l1_ttbr1:
651	.space	PAGE_SIZE
652pagetable_l0_ttbr1:
653	.space	PAGE_SIZE
654pagetable_l1_ttbr0:
655	.space	PAGE_SIZE
656pagetable_l0_ttbr0:
657	.space	PAGE_SIZE
658
659	.globl pagetable_dmap
660pagetable_dmap:
661	.space	PAGE_SIZE * DMAP_TABLES
662pagetable_end:
663
664el2_pagetable:
665	.space	PAGE_SIZE
666
667	.globl init_pt_va
668init_pt_va:
669	.quad pagetable		/* XXX: Keep page tables VA */
670
671	.align	4
672initstack:
673	.space	(PAGE_SIZE * KSTACK_PAGES)
674initstack_end:
675
676
677ENTRY(sigcode)
678	mov	x0, sp
679	add	x0, x0, #SF_UC
680
6811:
682	mov	x8, #SYS_sigreturn
683	svc	0
684
685	/* sigreturn failed, exit */
686	mov	x8, #SYS_exit
687	svc	0
688
689	b	1b
690END(sigcode)
691	/* This may be copied to the stack, keep it 16-byte aligned */
692	.align	3
693esigcode:
694
695	.data
696	.align	3
697	.global	szsigcode
698szsigcode:
699	.quad	esigcode - sigcode
700