summaryrefslogtreecommitdiffstats
path: root/arch/arm64/mm/proc.S
blob: b9ecbbae1e1abca1bdadfdc33f30c56bbb0074cd (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
/* SPDX-License-Identifier: GPL-2.0-only */
/*
 * Based on arch/arm/mm/proc.S
 *
 * Copyright (C) 2001 Deep Blue Solutions Ltd.
 * Copyright (C) 2012 ARM Ltd.
 * Author: Catalin Marinas <catalin.marinas@arm.com>
 */

#include <linux/init.h>
#include <linux/linkage.h>
#include <linux/pgtable.h>
#include <linux/cfi_types.h>
#include <asm/assembler.h>
#include <asm/asm-offsets.h>
#include <asm/asm_pointer_auth.h>
#include <asm/hwcap.h>
#include <asm/kernel-pgtable.h>
#include <asm/pgtable-hwdef.h>
#include <asm/cpufeature.h>
#include <asm/alternative.h>
#include <asm/smp.h>
#include <asm/sysreg.h>

#ifdef CONFIG_ARM64_64K_PAGES
#define TCR_TG_FLAGS	TCR_TG0_64K | TCR_TG1_64K
#elif defined(CONFIG_ARM64_16K_PAGES)
#define TCR_TG_FLAGS	TCR_TG0_16K | TCR_TG1_16K
#else /* CONFIG_ARM64_4K_PAGES */
#define TCR_TG_FLAGS	TCR_TG0_4K | TCR_TG1_4K
#endif

#ifdef CONFIG_RANDOMIZE_BASE
#define TCR_KASLR_FLAGS	TCR_NFD1
#else
#define TCR_KASLR_FLAGS	0
#endif

#define TCR_SMP_FLAGS	TCR_SHARED

/* PTWs cacheable, inner/outer WBWA */
#define TCR_CACHE_FLAGS	TCR_IRGN_WBWA | TCR_ORGN_WBWA

#ifdef CONFIG_KASAN_SW_TAGS
#define TCR_KASAN_SW_FLAGS TCR_TBI1 | TCR_TBID1
#else
#define TCR_KASAN_SW_FLAGS 0
#endif

#ifdef CONFIG_KASAN_HW_TAGS
#define TCR_MTE_FLAGS TCR_TCMA1 | TCR_TBI1 | TCR_TBID1
#elif defined(CONFIG_ARM64_MTE)
/*
 * The mte_zero_clear_page_tags() implementation uses DC GZVA, which relies on
 * TBI being enabled at EL1.
 */
#define TCR_MTE_FLAGS TCR_TBI1 | TCR_TBID1
#else
#define TCR_MTE_FLAGS 0
#endif

/*
 * Default MAIR_EL1. MT_NORMAL_TAGGED is initially mapped as Normal memory and
 * changed during mte_cpu_setup to Normal Tagged if the system supports MTE.
 */
#define MAIR_EL1_SET							\
	(MAIR_ATTRIDX(MAIR_ATTR_DEVICE_nGnRnE, MT_DEVICE_nGnRnE) |	\
	 MAIR_ATTRIDX(MAIR_ATTR_DEVICE_nGnRE, MT_DEVICE_nGnRE) |	\
	 MAIR_ATTRIDX(MAIR_ATTR_NORMAL_NC, MT_NORMAL_NC) |		\
	 MAIR_ATTRIDX(MAIR_ATTR_NORMAL, MT_NORMAL) |			\
	 MAIR_ATTRIDX(MAIR_ATTR_NORMAL, MT_NORMAL_TAGGED))

#ifdef CONFIG_CPU_PM
/**
 * cpu_do_suspend - save CPU registers context
 *
 * x0: virtual address of context pointer
 *
 * This must be kept in sync with struct cpu_suspend_ctx in <asm/suspend.h>.
 */
SYM_FUNC_START(cpu_do_suspend)
	mrs	x2, tpidr_el0
	mrs	x3, tpidrro_el0
	mrs	x4, contextidr_el1
	mrs	x5, osdlr_el1
	mrs	x6, cpacr_el1
	mrs	x7, tcr_el1
	mrs	x8, vbar_el1
	mrs	x9, mdscr_el1
	mrs	x10, oslsr_el1
	mrs	x11, sctlr_el1
	get_this_cpu_offset x12
	mrs	x13, sp_el0
	stp	x2, x3, [x0]
	stp	x4, x5, [x0, #16]
	stp	x6, x7, [x0, #32]
	stp	x8, x9, [x0, #48]
	stp	x10, x11, [x0, #64]
	stp	x12, x13, [x0, #80]
	/*
	 * Save x18 as it may be used as a platform register, e.g. by shadow
	 * call stack.
	 */
	str	x18, [x0, #96]
	ret
SYM_FUNC_END(cpu_do_suspend)

/**
 * cpu_do_resume - restore CPU register context
 *
 * x0: Address of context pointer
 */
	.pushsection ".idmap.text", "awx"
SYM_FUNC_START(cpu_do_resume)
	ldp	x2, x3, [x0]
	ldp	x4, x5, [x0, #16]
	ldp	x6, x8, [x0, #32]
	ldp	x9, x10, [x0, #48]
	ldp	x11, x12, [x0, #64]
	ldp	x13, x14, [x0, #80]
	/*
	 * Restore x18, as it may be used as a platform register, and clear
	 * the buffer to minimize the risk of exposure when used for shadow
	 * call stack.
	 */
	ldr	x18, [x0, #96]
	str	xzr, [x0, #96]
	msr	tpidr_el0, x2
	msr	tpidrro_el0, x3
	msr	contextidr_el1, x4
	msr	cpacr_el1, x6

	/* Don't change t0sz here, mask those bits when restoring */
	mrs	x7, tcr_el1
	bfi	x8, x7, TCR_T0SZ_OFFSET, TCR_TxSZ_WIDTH

	msr	tcr_el1, x8
	msr	vbar_el1, x9

	/*
	 * __cpu_setup() cleared MDSCR_EL1.MDE and friends, before unmasking
	 * debug exceptions. By restoring MDSCR_EL1 here, we may take a debug
	 * exception. Mask them until local_daif_restore() in cpu_suspend()
	 * resets them.
	 */
	disable_daif
	msr	mdscr_el1, x10

	msr	sctlr_el1, x12
	set_this_cpu_offset x13
	msr	sp_el0, x14
	/*
	 * Restore oslsr_el1 by writing oslar_el1
	 */
	msr	osdlr_el1, x5
	ubfx	x11, x11, #1, #1
	msr	oslar_el1, x11
	reset_pmuserenr_el0 x0			// Disable PMU access from EL0
	reset_amuserenr_el0 x0			// Disable AMU access from EL0

alternative_if ARM64_HAS_RAS_EXTN
	msr_s	SYS_DISR_EL1, xzr
alternative_else_nop_endif

	ptrauth_keys_install_kernel_nosync x14, x1, x2, x3
	isb
	ret
SYM_FUNC_END(cpu_do_resume)
	.popsection
#endif

	.pushsection ".idmap.text", "awx"

.macro	__idmap_cpu_set_reserved_ttbr1, tmp1, tmp2
	adrp	\tmp1, reserved_pg_dir
	phys_to_ttbr \tmp2, \tmp1
	offset_ttbr1 \tmp2, \tmp1
	msr	ttbr1_el1, \tmp2
	isb
	tlbi	vmalle1
	dsb	nsh
	isb
.endm

/*
 * void idmap_cpu_replace_ttbr1(phys_addr_t ttbr1)
 *
 * This is the low-level counterpart to cpu_replace_ttbr1, and should not be
 * called by anything else. It can only be executed from a TTBR0 mapping.
 */
SYM_TYPED_FUNC_START(idmap_cpu_replace_ttbr1)
	save_and_disable_daif flags=x2

	__idmap_cpu_set_reserved_ttbr1 x1, x3

	offset_ttbr1 x0, x3
	msr	ttbr1_el1, x0
	isb

	restore_daif x2

	ret
SYM_FUNC_END(idmap_cpu_replace_ttbr1)
	.popsection

#ifdef CONFIG_UNMAP_KERNEL_AT_EL0

#define KPTI_NG_PTE_FLAGS	(PTE_ATTRINDX(MT_NORMAL) | SWAPPER_PTE_FLAGS)

	.pushsection ".idmap.text", "awx"

	.macro	kpti_mk_tbl_ng, type, num_entries
	add	end_\type\()p, cur_\type\()p, #\num_entries * 8
.Ldo_\type:
	ldr	\type, [cur_\type\()p]		// Load the entry
	tbz	\type, #0, .Lnext_\type		// Skip invalid and
	tbnz	\type, #11, .Lnext_\type	// non-global entries
	orr	\type, \type, #PTE_NG		// Same bit for blocks and pages
	str	\type, [cur_\type\()p]		// Update the entry
	.ifnc	\type, pte
	tbnz	\type, #1, .Lderef_\type
	.endif
.Lnext_\type:
	add	cur_\type\()p, cur_\type\()p, #8
	cmp	cur_\type\()p, end_\type\()p
	b.ne	.Ldo_\type
	.endm

	/*
	 * Dereference the current table entry and map it into the temporary
	 * fixmap slot associated with the current level.
	 */
	.macro	kpti_map_pgtbl, type, level
	str	xzr, [temp_pte, #8 * (\level + 1)]	// break before make
	dsb	nshst
	add	pte, temp_pte, #PAGE_SIZE * (\level + 1)
	lsr	pte, pte, #12
	tlbi	vaae1, pte
	dsb	nsh
	isb

	phys_to_pte pte, cur_\type\()p
	add	cur_\type\()p, temp_pte, #PAGE_SIZE * (\level + 1)
	orr	pte, pte, pte_flags
	str	pte, [temp_pte, #8 * (\level + 1)]
	dsb	nshst
	.endm

/*
 * void __kpti_install_ng_mappings(int cpu, int num_secondaries, phys_addr_t temp_pgd,
 *				   unsigned long temp_pte_va)
 *
 * Called exactly once from stop_machine context by each CPU found during boot.
 */
	.pushsection	".data", "aw", %progbits
SYM_DATA(__idmap_kpti_flag, .long 1)
	.popsection

SYM_TYPED_FUNC_START(idmap_kpti_install_ng_mappings)
	cpu		.req	w0
	temp_pte	.req	x0
	num_cpus	.req	w1
	pte_flags	.req	x1
	temp_pgd_phys	.req	x2
	swapper_ttb	.req	x3
	flag_ptr	.req	x4
	cur_pgdp	.req	x5
	end_pgdp	.req	x6
	pgd		.req	x7
	cur_pudp	.req	x8
	end_pudp	.req	x9
	cur_pmdp	.req	x11
	end_pmdp	.req	x12
	cur_ptep	.req	x14
	end_ptep	.req	x15
	pte		.req	x16
	valid		.req	x17

	mov	x5, x3				// preserve temp_pte arg
	mrs	swapper_ttb, ttbr1_el1
	adr_l	flag_ptr, __idmap_kpti_flag

	cbnz	cpu, __idmap_kpti_secondary

	/* We're the boot CPU. Wait for the others to catch up */
	sevl
1:	wfe
	ldaxr	w17, [flag_ptr]
	eor	w17, w17, num_cpus
	cbnz	w17, 1b

	/* Switch to the temporary page tables on this CPU only */
	__idmap_cpu_set_reserved_ttbr1 x8, x9
	offset_ttbr1 temp_pgd_phys, x8
	msr	ttbr1_el1, temp_pgd_phys
	isb

	mov	temp_pte, x5
	mov	pte_flags, #KPTI_NG_PTE_FLAGS

	/* Everybody is enjoying the idmap, so we can rewrite swapper. */
	/* PGD */
	adrp		cur_pgdp, swapper_pg_dir
	kpti_map_pgtbl	pgd, 0
	kpti_mk_tbl_ng	pgd, PTRS_PER_PGD

	/* Ensure all the updated entries are visible to secondary CPUs */
	dsb	ishst

	/* We're done: fire up swapper_pg_dir again */
	__idmap_cpu_set_reserved_ttbr1 x8, x9
	msr	ttbr1_el1, swapper_ttb
	isb

	/* Set the flag to zero to indicate that we're all done */
	str	wzr, [flag_ptr]
	ret

.Lderef_pgd:
	/* PUD */
	.if		CONFIG_PGTABLE_LEVELS > 3
	pud		.req	x10
	pte_to_phys	cur_pudp, pgd
	kpti_map_pgtbl	pud, 1
	kpti_mk_tbl_ng	pud, PTRS_PER_PUD
	b		.Lnext_pgd
	.else		/* CONFIG_PGTABLE_LEVELS <= 3 */
	pud		.req	pgd
	.set		.Lnext_pud, .Lnext_pgd
	.endif

.Lderef_pud:
	/* PMD */
	.if		CONFIG_PGTABLE_LEVELS > 2
	pmd		.req	x13
	pte_to_phys	cur_pmdp, pud
	kpti_map_pgtbl	pmd, 2
	kpti_mk_tbl_ng	pmd, PTRS_PER_PMD
	b		.Lnext_pud
	.else		/* CONFIG_PGTABLE_LEVELS <= 2 */
	pmd		.req	pgd
	.set		.Lnext_pmd, .Lnext_pgd
	.endif

.Lderef_pmd:
	/* PTE */
	pte_to_phys	cur_ptep, pmd
	kpti_map_pgtbl	pte, 3
	kpti_mk_tbl_ng	pte, PTRS_PER_PTE
	b		.Lnext_pmd

	.unreq	cpu
	.unreq	temp_pte
	.unreq	num_cpus
	.unreq	pte_flags
	.unreq	temp_pgd_phys
	.unreq	cur_pgdp
	.unreq	end_pgdp
	.unreq	pgd
	.unreq	cur_pudp
	.unreq	end_pudp
	.unreq	pud
	.unreq	cur_pmdp
	.unreq	end_pmdp
	.unreq	pmd
	.unreq	cur_ptep
	.unreq	end_ptep
	.unreq	pte
	.unreq	valid

	/* Secondary CPUs end up here */
__idmap_kpti_secondary:
	/* Uninstall swapper before surgery begins */
	__idmap_cpu_set_reserved_ttbr1 x16, x17

	/* Increment the flag to let the boot CPU we're ready */
1:	ldxr	w16, [flag_ptr]
	add	w16, w16, #1
	stxr	w17, w16, [flag_ptr]
	cbnz	w17, 1b

	/* Wait for the boot CPU to finish messing around with swapper */
	sevl
1:	wfe
	ldxr	w16, [flag_ptr]
	cbnz	w16, 1b

	/* All done, act like nothing happened */
	msr	ttbr1_el1, swapper_ttb
	isb
	ret

	.unreq	swapper_ttb
	.unreq	flag_ptr
SYM_FUNC_END(idmap_kpti_install_ng_mappings)
	.popsection
#endif

/*
 *	__cpu_setup
 *
 *	Initialise the processor for turning the MMU on.
 *
 * Input:
 *	x0 - actual number of VA bits (ignored unless VA_BITS > 48)
 * Output:
 *	Return in x0 the value of the SCTLR_EL1 register.
 */
	.pushsection ".idmap.text", "awx"
SYM_FUNC_START(__cpu_setup)
	tlbi	vmalle1				// Invalidate local TLB
	dsb	nsh

	mov	x1, #3 << 20
	msr	cpacr_el1, x1			// Enable FP/ASIMD
	mov	x1, #1 << 12			// Reset mdscr_el1 and disable
	msr	mdscr_el1, x1			// access to the DCC from EL0
	isb					// Unmask debug exceptions now,
	enable_dbg				// since this is per-cpu
	reset_pmuserenr_el0 x1			// Disable PMU access from EL0
	reset_amuserenr_el0 x1			// Disable AMU access from EL0

	/*
	 * Default values for VMSA control registers. These will be adjusted
	 * below depending on detected CPU features.
	 */
	mair	.req	x17
	tcr	.req	x16
	mov_q	mair, MAIR_EL1_SET
	mov_q	tcr, TCR_TxSZ(VA_BITS) | TCR_CACHE_FLAGS | TCR_SMP_FLAGS | \
			TCR_TG_FLAGS | TCR_KASLR_FLAGS | TCR_ASID16 | \
			TCR_TBI0 | TCR_A1 | TCR_KASAN_SW_FLAGS | TCR_MTE_FLAGS

	tcr_clear_errata_bits tcr, x9, x5

#ifdef CONFIG_ARM64_VA_BITS_52
	sub		x9, xzr, x0
	add		x9, x9, #64
	tcr_set_t1sz	tcr, x9
#else
	idmap_get_t0sz	x9
#endif
	tcr_set_t0sz	tcr, x9

	/*
	 * Set the IPS bits in TCR_EL1.
	 */
	tcr_compute_pa_size tcr, #TCR_IPS_SHIFT, x5, x6
#ifdef CONFIG_ARM64_HW_AFDBM
	/*
	 * Enable hardware update of the Access Flags bit.
	 * Hardware dirty bit management is enabled later,
	 * via capabilities.
	 */
	mrs	x9, ID_AA64MMFR1_EL1
	and	x9, x9, #0xf
	cbz	x9, 1f
	orr	tcr, tcr, #TCR_HA		// hardware Access flag update
1:
#endif	/* CONFIG_ARM64_HW_AFDBM */
	msr	mair_el1, mair
	msr	tcr_el1, tcr
	/*
	 * Prepare SCTLR
	 */
	mov_q	x0, INIT_SCTLR_EL1_MMU_ON
	ret					// return to head.S

	.unreq	mair
	.unreq	tcr
SYM_FUNC_END(__cpu_setup)