xref: /openbmc/linux/arch/arm64/mm/proc.S (revision f2d8e15b) 
1/* SPDX-License-Identifier: GPL-2.0-only */
2/*
3 * Based on arch/arm/mm/proc.S
4 *
5 * Copyright (C) 2001 Deep Blue Solutions Ltd.
6 * Copyright (C) 2012 ARM Ltd.
7 * Author: Catalin Marinas <catalin.marinas@arm.com>
8 */
9
10#include <linux/init.h>
11#include <linux/linkage.h>
12#include <linux/pgtable.h>
13#include <asm/assembler.h>
14#include <asm/asm-offsets.h>
15#include <asm/asm_pointer_auth.h>
16#include <asm/hwcap.h>
17#include <asm/kernel-pgtable.h>
18#include <asm/pgtable-hwdef.h>
19#include <asm/cpufeature.h>
20#include <asm/alternative.h>
21#include <asm/smp.h>
22#include <asm/sysreg.h>
23
24#ifdef CONFIG_ARM64_64K_PAGES
25#define TCR_TG_FLAGS	TCR_TG0_64K | TCR_TG1_64K
26#elif defined(CONFIG_ARM64_16K_PAGES)
27#define TCR_TG_FLAGS	TCR_TG0_16K | TCR_TG1_16K
28#else /* CONFIG_ARM64_4K_PAGES */
29#define TCR_TG_FLAGS	TCR_TG0_4K | TCR_TG1_4K
30#endif
31
32#ifdef CONFIG_RANDOMIZE_BASE
33#define TCR_KASLR_FLAGS	TCR_NFD1
34#else
35#define TCR_KASLR_FLAGS	0
36#endif
37
38#define TCR_SMP_FLAGS	TCR_SHARED
39
40/* PTWs cacheable, inner/outer WBWA */
41#define TCR_CACHE_FLAGS	TCR_IRGN_WBWA | TCR_ORGN_WBWA
42
43#ifdef CONFIG_KASAN_SW_TAGS
44#define TCR_KASAN_SW_FLAGS TCR_TBI1 | TCR_TBID1
45#else
46#define TCR_KASAN_SW_FLAGS 0
47#endif
48
49#ifdef CONFIG_KASAN_HW_TAGS
50#define TCR_MTE_FLAGS TCR_TCMA1 | TCR_TBI1 | TCR_TBID1
51#else
52/*
53 * The mte_zero_clear_page_tags() implementation uses DC GZVA, which relies on
54 * TBI being enabled at EL1.
55 */
56#define TCR_MTE_FLAGS TCR_TBI1 | TCR_TBID1
57#endif
58
59/*
60 * Default MAIR_EL1. MT_NORMAL_TAGGED is initially mapped as Normal memory and
61 * changed during __cpu_setup to Normal Tagged if the system supports MTE.
62 */
63#define MAIR_EL1_SET							\
64	(MAIR_ATTRIDX(MAIR_ATTR_DEVICE_nGnRnE, MT_DEVICE_nGnRnE) |	\
65	 MAIR_ATTRIDX(MAIR_ATTR_DEVICE_nGnRE, MT_DEVICE_nGnRE) |	\
66	 MAIR_ATTRIDX(MAIR_ATTR_NORMAL_NC, MT_NORMAL_NC) |		\
67	 MAIR_ATTRIDX(MAIR_ATTR_NORMAL, MT_NORMAL) |			\
68	 MAIR_ATTRIDX(MAIR_ATTR_NORMAL, MT_NORMAL_TAGGED))
69
70#ifdef CONFIG_CPU_PM
71/**
72 * cpu_do_suspend - save CPU registers context
73 *
74 * x0: virtual address of context pointer
75 *
76 * This must be kept in sync with struct cpu_suspend_ctx in <asm/suspend.h>.
77 */
78SYM_FUNC_START(cpu_do_suspend)
79	mrs	x2, tpidr_el0
80	mrs	x3, tpidrro_el0
81	mrs	x4, contextidr_el1
82	mrs	x5, osdlr_el1
83	mrs	x6, cpacr_el1
84	mrs	x7, tcr_el1
85	mrs	x8, vbar_el1
86	mrs	x9, mdscr_el1
87	mrs	x10, oslsr_el1
88	mrs	x11, sctlr_el1
89	get_this_cpu_offset x12
90	mrs	x13, sp_el0
91	stp	x2, x3, [x0]
92	stp	x4, x5, [x0, #16]
93	stp	x6, x7, [x0, #32]
94	stp	x8, x9, [x0, #48]
95	stp	x10, x11, [x0, #64]
96	stp	x12, x13, [x0, #80]
97	/*
98	 * Save x18 as it may be used as a platform register, e.g. by shadow
99	 * call stack.
100	 */
101	str	x18, [x0, #96]
102	ret
103SYM_FUNC_END(cpu_do_suspend)
104
105/**
106 * cpu_do_resume - restore CPU register context
107 *
108 * x0: Address of context pointer
109 */
110	.pushsection ".idmap.text", "awx"
111SYM_FUNC_START(cpu_do_resume)
112	ldp	x2, x3, [x0]
113	ldp	x4, x5, [x0, #16]
114	ldp	x6, x8, [x0, #32]
115	ldp	x9, x10, [x0, #48]
116	ldp	x11, x12, [x0, #64]
117	ldp	x13, x14, [x0, #80]
118	/*
119	 * Restore x18, as it may be used as a platform register, and clear
120	 * the buffer to minimize the risk of exposure when used for shadow
121	 * call stack.
122	 */
123	ldr	x18, [x0, #96]
124	str	xzr, [x0, #96]
125	msr	tpidr_el0, x2
126	msr	tpidrro_el0, x3
127	msr	contextidr_el1, x4
128	msr	cpacr_el1, x6
129
130	/* Don't change t0sz here, mask those bits when restoring */
131	mrs	x7, tcr_el1
132	bfi	x8, x7, TCR_T0SZ_OFFSET, TCR_TxSZ_WIDTH
133
134	msr	tcr_el1, x8
135	msr	vbar_el1, x9
136
137	/*
138	 * __cpu_setup() cleared MDSCR_EL1.MDE and friends, before unmasking
139	 * debug exceptions. By restoring MDSCR_EL1 here, we may take a debug
140	 * exception. Mask them until local_daif_restore() in cpu_suspend()
141	 * resets them.
142	 */
143	disable_daif
144	msr	mdscr_el1, x10
145
146	msr	sctlr_el1, x12
147	set_this_cpu_offset x13
148	msr	sp_el0, x14
149	/*
150	 * Restore oslsr_el1 by writing oslar_el1
151	 */
152	msr	osdlr_el1, x5
153	ubfx	x11, x11, #1, #1
154	msr	oslar_el1, x11
155	reset_pmuserenr_el0 x0			// Disable PMU access from EL0
156	reset_amuserenr_el0 x0			// Disable AMU access from EL0
157
158alternative_if ARM64_HAS_RAS_EXTN
159	msr_s	SYS_DISR_EL1, xzr
160alternative_else_nop_endif
161
162	ptrauth_keys_install_kernel_nosync x14, x1, x2, x3
163	isb
164	ret
165SYM_FUNC_END(cpu_do_resume)
166	.popsection
167#endif
168
169	.pushsection ".idmap.text", "awx"
170
171.macro	__idmap_cpu_set_reserved_ttbr1, tmp1, tmp2
172	adrp	\tmp1, reserved_pg_dir
173	phys_to_ttbr \tmp2, \tmp1
174	offset_ttbr1 \tmp2, \tmp1
175	msr	ttbr1_el1, \tmp2
176	isb
177	tlbi	vmalle1
178	dsb	nsh
179	isb
180.endm
181
182/*
183 * void idmap_cpu_replace_ttbr1(phys_addr_t ttbr1)
184 *
185 * This is the low-level counterpart to cpu_replace_ttbr1, and should not be
186 * called by anything else. It can only be executed from a TTBR0 mapping.
187 */
188SYM_FUNC_START(idmap_cpu_replace_ttbr1)
189	save_and_disable_daif flags=x2
190
191	__idmap_cpu_set_reserved_ttbr1 x1, x3
192
193	offset_ttbr1 x0, x3
194	msr	ttbr1_el1, x0
195	isb
196
197	restore_daif x2
198
199	ret
200SYM_FUNC_END(idmap_cpu_replace_ttbr1)
201	.popsection
202
203#ifdef CONFIG_UNMAP_KERNEL_AT_EL0
204
205#define KPTI_NG_PTE_FLAGS	(PTE_ATTRINDX(MT_NORMAL) | SWAPPER_PTE_FLAGS)
206
207	.pushsection ".idmap.text", "awx"
208
209	.macro	kpti_mk_tbl_ng, type, num_entries
210	add	end_\type\()p, cur_\type\()p, #\num_entries * 8
211.Ldo_\type:
212	ldr	\type, [cur_\type\()p]		// Load the entry
213	tbz	\type, #0, .Lnext_\type		// Skip invalid and
214	tbnz	\type, #11, .Lnext_\type	// non-global entries
215	orr	\type, \type, #PTE_NG		// Same bit for blocks and pages
216	str	\type, [cur_\type\()p]		// Update the entry
217	.ifnc	\type, pte
218	tbnz	\type, #1, .Lderef_\type
219	.endif
220.Lnext_\type:
221	add	cur_\type\()p, cur_\type\()p, #8
222	cmp	cur_\type\()p, end_\type\()p
223	b.ne	.Ldo_\type
224	.endm
225
226	/*
227	 * Dereference the current table entry and map it into the temporary
228	 * fixmap slot associated with the current level.
229	 */
230	.macro	kpti_map_pgtbl, type, level
231	str	xzr, [temp_pte, #8 * (\level + 1)]	// break before make
232	dsb	nshst
233	add	pte, temp_pte, #PAGE_SIZE * (\level + 1)
234	lsr	pte, pte, #12
235	tlbi	vaae1, pte
236	dsb	nsh
237	isb
238
239	phys_to_pte pte, cur_\type\()p
240	add	cur_\type\()p, temp_pte, #PAGE_SIZE * (\level + 1)
241	orr	pte, pte, pte_flags
242	str	pte, [temp_pte, #8 * (\level + 1)]
243	dsb	nshst
244	.endm
245
246/*
247 * void __kpti_install_ng_mappings(int cpu, int num_secondaries, phys_addr_t temp_pgd,
248 *				   unsigned long temp_pte_va)
249 *
250 * Called exactly once from stop_machine context by each CPU found during boot.
251 */
252	.pushsection	".data", "aw", %progbits
253SYM_DATA(__idmap_kpti_flag, .long 1)
254	.popsection
255
256SYM_FUNC_START(idmap_kpti_install_ng_mappings)
257	cpu		.req	w0
258	temp_pte	.req	x0
259	num_cpus	.req	w1
260	pte_flags	.req	x1
261	temp_pgd_phys	.req	x2
262	swapper_ttb	.req	x3
263	flag_ptr	.req	x4
264	cur_pgdp	.req	x5
265	end_pgdp	.req	x6
266	pgd		.req	x7
267	cur_pudp	.req	x8
268	end_pudp	.req	x9
269	cur_pmdp	.req	x11
270	end_pmdp	.req	x12
271	cur_ptep	.req	x14
272	end_ptep	.req	x15
273	pte		.req	x16
274	valid		.req	x17
275
276	mov	x5, x3				// preserve temp_pte arg
277	mrs	swapper_ttb, ttbr1_el1
278	adr_l	flag_ptr, __idmap_kpti_flag
279
280	cbnz	cpu, __idmap_kpti_secondary
281
282	/* We're the boot CPU. Wait for the others to catch up */
283	sevl
2841:	wfe
285	ldaxr	w17, [flag_ptr]
286	eor	w17, w17, num_cpus
287	cbnz	w17, 1b
288
289	/* Switch to the temporary page tables on this CPU only */
290	__idmap_cpu_set_reserved_ttbr1 x8, x9
291	offset_ttbr1 temp_pgd_phys, x8
292	msr	ttbr1_el1, temp_pgd_phys
293	isb
294
295	mov	temp_pte, x5
296	mov	pte_flags, #KPTI_NG_PTE_FLAGS
297
298	/* Everybody is enjoying the idmap, so we can rewrite swapper. */
299	/* PGD */
300	adrp		cur_pgdp, swapper_pg_dir
301	kpti_map_pgtbl	pgd, 0
302	kpti_mk_tbl_ng	pgd, PTRS_PER_PGD
303
304	/* Ensure all the updated entries are visible to secondary CPUs */
305	dsb	ishst
306
307	/* We're done: fire up swapper_pg_dir again */
308	__idmap_cpu_set_reserved_ttbr1 x8, x9
309	msr	ttbr1_el1, swapper_ttb
310	isb
311
312	/* Set the flag to zero to indicate that we're all done */
313	str	wzr, [flag_ptr]
314	ret
315
316.Lderef_pgd:
317	/* PUD */
318	.if		CONFIG_PGTABLE_LEVELS > 3
319	pud		.req	x10
320	pte_to_phys	cur_pudp, pgd
321	kpti_map_pgtbl	pud, 1
322	kpti_mk_tbl_ng	pud, PTRS_PER_PUD
323	b		.Lnext_pgd
324	.else		/* CONFIG_PGTABLE_LEVELS <= 3 */
325	pud		.req	pgd
326	.set		.Lnext_pud, .Lnext_pgd
327	.endif
328
329.Lderef_pud:
330	/* PMD */
331	.if		CONFIG_PGTABLE_LEVELS > 2
332	pmd		.req	x13
333	pte_to_phys	cur_pmdp, pud
334	kpti_map_pgtbl	pmd, 2
335	kpti_mk_tbl_ng	pmd, PTRS_PER_PMD
336	b		.Lnext_pud
337	.else		/* CONFIG_PGTABLE_LEVELS <= 2 */
338	pmd		.req	pgd
339	.set		.Lnext_pmd, .Lnext_pgd
340	.endif
341
342.Lderef_pmd:
343	/* PTE */
344	pte_to_phys	cur_ptep, pmd
345	kpti_map_pgtbl	pte, 3
346	kpti_mk_tbl_ng	pte, PTRS_PER_PTE
347	b		.Lnext_pmd
348
349	.unreq	cpu
350	.unreq	temp_pte
351	.unreq	num_cpus
352	.unreq	pte_flags
353	.unreq	temp_pgd_phys
354	.unreq	cur_pgdp
355	.unreq	end_pgdp
356	.unreq	pgd
357	.unreq	cur_pudp
358	.unreq	end_pudp
359	.unreq	pud
360	.unreq	cur_pmdp
361	.unreq	end_pmdp
362	.unreq	pmd
363	.unreq	cur_ptep
364	.unreq	end_ptep
365	.unreq	pte
366	.unreq	valid
367
368	/* Secondary CPUs end up here */
369__idmap_kpti_secondary:
370	/* Uninstall swapper before surgery begins */
371	__idmap_cpu_set_reserved_ttbr1 x16, x17
372
373	/* Increment the flag to let the boot CPU we're ready */
3741:	ldxr	w16, [flag_ptr]
375	add	w16, w16, #1
376	stxr	w17, w16, [flag_ptr]
377	cbnz	w17, 1b
378
379	/* Wait for the boot CPU to finish messing around with swapper */
380	sevl
3811:	wfe
382	ldxr	w16, [flag_ptr]
383	cbnz	w16, 1b
384
385	/* All done, act like nothing happened */
386	msr	ttbr1_el1, swapper_ttb
387	isb
388	ret
389
390	.unreq	swapper_ttb
391	.unreq	flag_ptr
392SYM_FUNC_END(idmap_kpti_install_ng_mappings)
393	.popsection
394#endif
395
396/*
397 *	__cpu_setup
398 *
399 *	Initialise the processor for turning the MMU on.
400 *
401 * Input:
402 *	x0 - actual number of VA bits (ignored unless VA_BITS > 48)
403 * Output:
404 *	Return in x0 the value of the SCTLR_EL1 register.
405 */
406	.pushsection ".idmap.text", "awx"
407SYM_FUNC_START(__cpu_setup)
408	tlbi	vmalle1				// Invalidate local TLB
409	dsb	nsh
410
411	mov	x1, #3 << 20
412	msr	cpacr_el1, x1			// Enable FP/ASIMD
413	mov	x1, #1 << 12			// Reset mdscr_el1 and disable
414	msr	mdscr_el1, x1			// access to the DCC from EL0
415	isb					// Unmask debug exceptions now,
416	enable_dbg				// since this is per-cpu
417	reset_pmuserenr_el0 x1			// Disable PMU access from EL0
418	reset_amuserenr_el0 x1			// Disable AMU access from EL0
419
420	/*
421	 * Default values for VMSA control registers. These will be adjusted
422	 * below depending on detected CPU features.
423	 */
424	mair	.req	x17
425	tcr	.req	x16
426	mov_q	mair, MAIR_EL1_SET
427	mov_q	tcr, TCR_TxSZ(VA_BITS) | TCR_CACHE_FLAGS | TCR_SMP_FLAGS | \
428			TCR_TG_FLAGS | TCR_KASLR_FLAGS | TCR_ASID16 | \
429			TCR_TBI0 | TCR_A1 | TCR_KASAN_SW_FLAGS
430
431#ifdef CONFIG_ARM64_MTE
432	/*
433	 * Update MAIR_EL1, GCR_EL1 and TFSR*_EL1 if MTE is supported
434	 * (ID_AA64PFR1_EL1[11:8] > 1).
435	 */
436	mrs	x10, ID_AA64PFR1_EL1
437	ubfx	x10, x10, #ID_AA64PFR1_MTE_SHIFT, #4
438	cmp	x10, #ID_AA64PFR1_MTE
439	b.lt	1f
440
441	/* Normal Tagged memory type at the corresponding MAIR index */
442	mov	x10, #MAIR_ATTR_NORMAL_TAGGED
443	bfi	mair, x10, #(8 *  MT_NORMAL_TAGGED), #8
444
445	mov	x10, #KERNEL_GCR_EL1
446	msr_s	SYS_GCR_EL1, x10
447
448	/*
449	 * If GCR_EL1.RRND=1 is implemented the same way as RRND=0, then
450	 * RGSR_EL1.SEED must be non-zero for IRG to produce
451	 * pseudorandom numbers. As RGSR_EL1 is UNKNOWN out of reset, we
452	 * must initialize it.
453	 */
454	mrs	x10, CNTVCT_EL0
455	ands	x10, x10, #SYS_RGSR_EL1_SEED_MASK
456	csinc	x10, x10, xzr, ne
457	lsl	x10, x10, #SYS_RGSR_EL1_SEED_SHIFT
458	msr_s	SYS_RGSR_EL1, x10
459
460	/* clear any pending tag check faults in TFSR*_EL1 */
461	msr_s	SYS_TFSR_EL1, xzr
462	msr_s	SYS_TFSRE0_EL1, xzr
463
464	/* set the TCR_EL1 bits */
465	mov_q	x10, TCR_MTE_FLAGS
466	orr	tcr, tcr, x10
4671:
468#endif
469	tcr_clear_errata_bits tcr, x9, x5
470
471#ifdef CONFIG_ARM64_VA_BITS_52
472	sub		x9, xzr, x0
473	add		x9, x9, #64
474	tcr_set_t1sz	tcr, x9
475#else
476	idmap_get_t0sz	x9
477#endif
478	tcr_set_t0sz	tcr, x9
479
480	/*
481	 * Set the IPS bits in TCR_EL1.
482	 */
483	tcr_compute_pa_size tcr, #TCR_IPS_SHIFT, x5, x6
484#ifdef CONFIG_ARM64_HW_AFDBM
485	/*
486	 * Enable hardware update of the Access Flags bit.
487	 * Hardware dirty bit management is enabled later,
488	 * via capabilities.
489	 */
490	mrs	x9, ID_AA64MMFR1_EL1
491	and	x9, x9, #0xf
492	cbz	x9, 1f
493	orr	tcr, tcr, #TCR_HA		// hardware Access flag update
4941:
495#endif	/* CONFIG_ARM64_HW_AFDBM */
496	msr	mair_el1, mair
497	msr	tcr_el1, tcr
498	/*
499	 * Prepare SCTLR
500	 */
501	mov_q	x0, INIT_SCTLR_EL1_MMU_ON
502	ret					// return to head.S
503
504	.unreq	mair
505	.unreq	tcr
506SYM_FUNC_END(__cpu_setup)
507