xref: /openbmc/linux/arch/arm64/mm/proc.S (revision 413d6ed3) 
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/pgtable-hwdef.h>
18#include <asm/cpufeature.h>
19#include <asm/alternative.h>
20#include <asm/smp.h>
21#include <asm/sysreg.h>
22
23#ifdef CONFIG_ARM64_64K_PAGES
24#define TCR_TG_FLAGS	TCR_TG0_64K | TCR_TG1_64K
25#elif defined(CONFIG_ARM64_16K_PAGES)
26#define TCR_TG_FLAGS	TCR_TG0_16K | TCR_TG1_16K
27#else /* CONFIG_ARM64_4K_PAGES */
28#define TCR_TG_FLAGS	TCR_TG0_4K | TCR_TG1_4K
29#endif
30
31#ifdef CONFIG_RANDOMIZE_BASE
32#define TCR_KASLR_FLAGS	TCR_NFD1
33#else
34#define TCR_KASLR_FLAGS	0
35#endif
36
37#define TCR_SMP_FLAGS	TCR_SHARED
38
39/* PTWs cacheable, inner/outer WBWA */
40#define TCR_CACHE_FLAGS	TCR_IRGN_WBWA | TCR_ORGN_WBWA
41
42#ifdef CONFIG_KASAN_SW_TAGS
43#define TCR_KASAN_SW_FLAGS TCR_TBI1 | TCR_TBID1
44#else
45#define TCR_KASAN_SW_FLAGS 0
46#endif
47
48#ifdef CONFIG_KASAN_HW_TAGS
49#define TCR_KASAN_HW_FLAGS SYS_TCR_EL1_TCMA1 | TCR_TBI1 | TCR_TBID1
50#else
51#define TCR_KASAN_HW_FLAGS 0
52#endif
53
54/*
55 * Default MAIR_EL1. MT_NORMAL_TAGGED is initially mapped as Normal memory and
56 * changed during __cpu_setup to Normal Tagged if the system supports MTE.
57 */
58#define MAIR_EL1_SET							\
59	(MAIR_ATTRIDX(MAIR_ATTR_DEVICE_nGnRnE, MT_DEVICE_nGnRnE) |	\
60	 MAIR_ATTRIDX(MAIR_ATTR_DEVICE_nGnRE, MT_DEVICE_nGnRE) |	\
61	 MAIR_ATTRIDX(MAIR_ATTR_DEVICE_GRE, MT_DEVICE_GRE) |		\
62	 MAIR_ATTRIDX(MAIR_ATTR_NORMAL_NC, MT_NORMAL_NC) |		\
63	 MAIR_ATTRIDX(MAIR_ATTR_NORMAL, MT_NORMAL) |			\
64	 MAIR_ATTRIDX(MAIR_ATTR_NORMAL_WT, MT_NORMAL_WT) |		\
65	 MAIR_ATTRIDX(MAIR_ATTR_NORMAL, MT_NORMAL_TAGGED))
66
67#ifdef CONFIG_CPU_PM
68/**
69 * cpu_do_suspend - save CPU registers context
70 *
71 * x0: virtual address of context pointer
72 *
73 * This must be kept in sync with struct cpu_suspend_ctx in <asm/suspend.h>.
74 */
75SYM_FUNC_START(cpu_do_suspend)
76	mrs	x2, tpidr_el0
77	mrs	x3, tpidrro_el0
78	mrs	x4, contextidr_el1
79	mrs	x5, osdlr_el1
80	mrs	x6, cpacr_el1
81	mrs	x7, tcr_el1
82	mrs	x8, vbar_el1
83	mrs	x9, mdscr_el1
84	mrs	x10, oslsr_el1
85	mrs	x11, sctlr_el1
86alternative_if_not ARM64_HAS_VIRT_HOST_EXTN
87	mrs	x12, tpidr_el1
88alternative_else
89	mrs	x12, tpidr_el2
90alternative_endif
91	mrs	x13, sp_el0
92	stp	x2, x3, [x0]
93	stp	x4, x5, [x0, #16]
94	stp	x6, x7, [x0, #32]
95	stp	x8, x9, [x0, #48]
96	stp	x10, x11, [x0, #64]
97	stp	x12, x13, [x0, #80]
98	/*
99	 * Save x18 as it may be used as a platform register, e.g. by shadow
100	 * call stack.
101	 */
102	str	x18, [x0, #96]
103	ret
104SYM_FUNC_END(cpu_do_suspend)
105
106/**
107 * cpu_do_resume - restore CPU register context
108 *
109 * x0: Address of context pointer
110 */
111	.pushsection ".idmap.text", "awx"
112SYM_FUNC_START(cpu_do_resume)
113	ldp	x2, x3, [x0]
114	ldp	x4, x5, [x0, #16]
115	ldp	x6, x8, [x0, #32]
116	ldp	x9, x10, [x0, #48]
117	ldp	x11, x12, [x0, #64]
118	ldp	x13, x14, [x0, #80]
119	/*
120	 * Restore x18, as it may be used as a platform register, and clear
121	 * the buffer to minimize the risk of exposure when used for shadow
122	 * call stack.
123	 */
124	ldr	x18, [x0, #96]
125	str	xzr, [x0, #96]
126	msr	tpidr_el0, x2
127	msr	tpidrro_el0, x3
128	msr	contextidr_el1, x4
129	msr	cpacr_el1, x6
130
131	/* Don't change t0sz here, mask those bits when restoring */
132	mrs	x7, tcr_el1
133	bfi	x8, x7, TCR_T0SZ_OFFSET, TCR_TxSZ_WIDTH
134
135	msr	tcr_el1, x8
136	msr	vbar_el1, x9
137
138	/*
139	 * __cpu_setup() cleared MDSCR_EL1.MDE and friends, before unmasking
140	 * debug exceptions. By restoring MDSCR_EL1 here, we may take a debug
141	 * exception. Mask them until local_daif_restore() in cpu_suspend()
142	 * resets them.
143	 */
144	disable_daif
145	msr	mdscr_el1, x10
146
147	msr	sctlr_el1, x12
148alternative_if_not ARM64_HAS_VIRT_HOST_EXTN
149	msr	tpidr_el1, x13
150alternative_else
151	msr	tpidr_el2, x13
152alternative_endif
153	msr	sp_el0, x14
154	/*
155	 * Restore oslsr_el1 by writing oslar_el1
156	 */
157	msr	osdlr_el1, x5
158	ubfx	x11, x11, #1, #1
159	msr	oslar_el1, x11
160	reset_pmuserenr_el0 x0			// Disable PMU access from EL0
161	reset_amuserenr_el0 x0			// Disable AMU access from EL0
162
163alternative_if ARM64_HAS_RAS_EXTN
164	msr_s	SYS_DISR_EL1, xzr
165alternative_else_nop_endif
166
167	ptrauth_keys_install_kernel_nosync x14, x1, x2, x3
168	isb
169	ret
170SYM_FUNC_END(cpu_do_resume)
171	.popsection
172#endif
173
174	.pushsection ".idmap.text", "awx"
175
176.macro	__idmap_cpu_set_reserved_ttbr1, tmp1, tmp2
177	adrp	\tmp1, reserved_pg_dir
178	phys_to_ttbr \tmp2, \tmp1
179	offset_ttbr1 \tmp2, \tmp1
180	msr	ttbr1_el1, \tmp2
181	isb
182	tlbi	vmalle1
183	dsb	nsh
184	isb
185.endm
186
187/*
188 * void idmap_cpu_replace_ttbr1(phys_addr_t ttbr1)
189 *
190 * This is the low-level counterpart to cpu_replace_ttbr1, and should not be
191 * called by anything else. It can only be executed from a TTBR0 mapping.
192 */
193SYM_FUNC_START(idmap_cpu_replace_ttbr1)
194	save_and_disable_daif flags=x2
195
196	__idmap_cpu_set_reserved_ttbr1 x1, x3
197
198	offset_ttbr1 x0, x3
199	msr	ttbr1_el1, x0
200	isb
201
202	restore_daif x2
203
204	ret
205SYM_FUNC_END(idmap_cpu_replace_ttbr1)
206	.popsection
207
208#ifdef CONFIG_UNMAP_KERNEL_AT_EL0
209	.pushsection ".idmap.text", "awx"
210
211	.macro	__idmap_kpti_get_pgtable_ent, type
212	dc	cvac, cur_\()\type\()p		// Ensure any existing dirty
213	dmb	sy				// lines are written back before
214	ldr	\type, [cur_\()\type\()p]	// loading the entry
215	tbz	\type, #0, skip_\()\type	// Skip invalid and
216	tbnz	\type, #11, skip_\()\type	// non-global entries
217	.endm
218
219	.macro __idmap_kpti_put_pgtable_ent_ng, type
220	orr	\type, \type, #PTE_NG		// Same bit for blocks and pages
221	str	\type, [cur_\()\type\()p]	// Update the entry and ensure
222	dmb	sy				// that it is visible to all
223	dc	civac, cur_\()\type\()p		// CPUs.
224	.endm
225
226/*
227 * void __kpti_install_ng_mappings(int cpu, int num_cpus, phys_addr_t swapper)
228 *
229 * Called exactly once from stop_machine context by each CPU found during boot.
230 */
231__idmap_kpti_flag:
232	.long	1
233SYM_FUNC_START(idmap_kpti_install_ng_mappings)
234	cpu		.req	w0
235	num_cpus	.req	w1
236	swapper_pa	.req	x2
237	swapper_ttb	.req	x3
238	flag_ptr	.req	x4
239	cur_pgdp	.req	x5
240	end_pgdp	.req	x6
241	pgd		.req	x7
242	cur_pudp	.req	x8
243	end_pudp	.req	x9
244	pud		.req	x10
245	cur_pmdp	.req	x11
246	end_pmdp	.req	x12
247	pmd		.req	x13
248	cur_ptep	.req	x14
249	end_ptep	.req	x15
250	pte		.req	x16
251
252	mrs	swapper_ttb, ttbr1_el1
253	restore_ttbr1	swapper_ttb
254	adr	flag_ptr, __idmap_kpti_flag
255
256	cbnz	cpu, __idmap_kpti_secondary
257
258	/* We're the boot CPU. Wait for the others to catch up */
259	sevl
2601:	wfe
261	ldaxr	w17, [flag_ptr]
262	eor	w17, w17, num_cpus
263	cbnz	w17, 1b
264
265	/* We need to walk swapper, so turn off the MMU. */
266	pre_disable_mmu_workaround
267	mrs	x17, sctlr_el1
268	bic	x17, x17, #SCTLR_ELx_M
269	msr	sctlr_el1, x17
270	isb
271
272	/* Everybody is enjoying the idmap, so we can rewrite swapper. */
273	/* PGD */
274	mov	cur_pgdp, swapper_pa
275	add	end_pgdp, cur_pgdp, #(PTRS_PER_PGD * 8)
276do_pgd:	__idmap_kpti_get_pgtable_ent	pgd
277	tbnz	pgd, #1, walk_puds
278next_pgd:
279	__idmap_kpti_put_pgtable_ent_ng	pgd
280skip_pgd:
281	add	cur_pgdp, cur_pgdp, #8
282	cmp	cur_pgdp, end_pgdp
283	b.ne	do_pgd
284
285	/* Publish the updated tables and nuke all the TLBs */
286	dsb	sy
287	tlbi	vmalle1is
288	dsb	ish
289	isb
290
291	/* We're done: fire up the MMU again */
292	mrs	x17, sctlr_el1
293	orr	x17, x17, #SCTLR_ELx_M
294	set_sctlr_el1	x17
295
296	/* Set the flag to zero to indicate that we're all done */
297	str	wzr, [flag_ptr]
298	ret
299
300	/* PUD */
301walk_puds:
302	.if CONFIG_PGTABLE_LEVELS > 3
303	pte_to_phys	cur_pudp, pgd
304	add	end_pudp, cur_pudp, #(PTRS_PER_PUD * 8)
305do_pud:	__idmap_kpti_get_pgtable_ent	pud
306	tbnz	pud, #1, walk_pmds
307next_pud:
308	__idmap_kpti_put_pgtable_ent_ng	pud
309skip_pud:
310	add	cur_pudp, cur_pudp, 8
311	cmp	cur_pudp, end_pudp
312	b.ne	do_pud
313	b	next_pgd
314	.else /* CONFIG_PGTABLE_LEVELS <= 3 */
315	mov	pud, pgd
316	b	walk_pmds
317next_pud:
318	b	next_pgd
319	.endif
320
321	/* PMD */
322walk_pmds:
323	.if CONFIG_PGTABLE_LEVELS > 2
324	pte_to_phys	cur_pmdp, pud
325	add	end_pmdp, cur_pmdp, #(PTRS_PER_PMD * 8)
326do_pmd:	__idmap_kpti_get_pgtable_ent	pmd
327	tbnz	pmd, #1, walk_ptes
328next_pmd:
329	__idmap_kpti_put_pgtable_ent_ng	pmd
330skip_pmd:
331	add	cur_pmdp, cur_pmdp, #8
332	cmp	cur_pmdp, end_pmdp
333	b.ne	do_pmd
334	b	next_pud
335	.else /* CONFIG_PGTABLE_LEVELS <= 2 */
336	mov	pmd, pud
337	b	walk_ptes
338next_pmd:
339	b	next_pud
340	.endif
341
342	/* PTE */
343walk_ptes:
344	pte_to_phys	cur_ptep, pmd
345	add	end_ptep, cur_ptep, #(PTRS_PER_PTE * 8)
346do_pte:	__idmap_kpti_get_pgtable_ent	pte
347	__idmap_kpti_put_pgtable_ent_ng	pte
348skip_pte:
349	add	cur_ptep, cur_ptep, #8
350	cmp	cur_ptep, end_ptep
351	b.ne	do_pte
352	b	next_pmd
353
354	.unreq	cpu
355	.unreq	num_cpus
356	.unreq	swapper_pa
357	.unreq	cur_pgdp
358	.unreq	end_pgdp
359	.unreq	pgd
360	.unreq	cur_pudp
361	.unreq	end_pudp
362	.unreq	pud
363	.unreq	cur_pmdp
364	.unreq	end_pmdp
365	.unreq	pmd
366	.unreq	cur_ptep
367	.unreq	end_ptep
368	.unreq	pte
369
370	/* Secondary CPUs end up here */
371__idmap_kpti_secondary:
372	/* Uninstall swapper before surgery begins */
373	__idmap_cpu_set_reserved_ttbr1 x16, x17
374
375	/* Increment the flag to let the boot CPU we're ready */
3761:	ldxr	w16, [flag_ptr]
377	add	w16, w16, #1
378	stxr	w17, w16, [flag_ptr]
379	cbnz	w17, 1b
380
381	/* Wait for the boot CPU to finish messing around with swapper */
382	sevl
3831:	wfe
384	ldxr	w16, [flag_ptr]
385	cbnz	w16, 1b
386
387	/* All done, act like nothing happened */
388	offset_ttbr1 swapper_ttb, x16
389	msr	ttbr1_el1, swapper_ttb
390	isb
391	ret
392
393	.unreq	swapper_ttb
394	.unreq	flag_ptr
395SYM_FUNC_END(idmap_kpti_install_ng_mappings)
396	.popsection
397#endif
398
399/*
400 *	__cpu_setup
401 *
402 *	Initialise the processor for turning the MMU on.
403 *
404 * Output:
405 *	Return in x0 the value of the SCTLR_EL1 register.
406 */
407	.pushsection ".idmap.text", "awx"
408SYM_FUNC_START(__cpu_setup)
409	tlbi	vmalle1				// Invalidate local TLB
410	dsb	nsh
411
412	mov	x1, #3 << 20
413	msr	cpacr_el1, x1			// Enable FP/ASIMD
414	mov	x1, #1 << 12			// Reset mdscr_el1 and disable
415	msr	mdscr_el1, x1			// access to the DCC from EL0
416	isb					// Unmask debug exceptions now,
417	enable_dbg				// since this is per-cpu
418	reset_pmuserenr_el0 x1			// Disable PMU access from EL0
419	reset_amuserenr_el0 x1			// Disable AMU access from EL0
420
421	/*
422	 * Default values for VMSA control registers. These will be adjusted
423	 * below depending on detected CPU features.
424	 */
425	mair	.req	x17
426	tcr	.req	x16
427	mov_q	mair, MAIR_EL1_SET
428	mov_q	tcr, TCR_TxSZ(VA_BITS) | TCR_CACHE_FLAGS | TCR_SMP_FLAGS | \
429			TCR_TG_FLAGS | TCR_KASLR_FLAGS | TCR_ASID16 | \
430			TCR_TBI0 | TCR_A1 | TCR_KASAN_SW_FLAGS
431
432#ifdef CONFIG_ARM64_MTE
433	/*
434	 * Update MAIR_EL1, GCR_EL1 and TFSR*_EL1 if MTE is supported
435	 * (ID_AA64PFR1_EL1[11:8] > 1).
436	 */
437	mrs	x10, ID_AA64PFR1_EL1
438	ubfx	x10, x10, #ID_AA64PFR1_MTE_SHIFT, #4
439	cmp	x10, #ID_AA64PFR1_MTE
440	b.lt	1f
441
442	/* Normal Tagged memory type at the corresponding MAIR index */
443	mov	x10, #MAIR_ATTR_NORMAL_TAGGED
444	bfi	mair, x10, #(8 *  MT_NORMAL_TAGGED), #8
445
446	/* initialize GCR_EL1: all non-zero tags excluded by default */
447	mov	x10, #(SYS_GCR_EL1_RRND | SYS_GCR_EL1_EXCL_MASK)
448	msr_s	SYS_GCR_EL1, x10
449
450	/*
451	 * If GCR_EL1.RRND=1 is implemented the same way as RRND=0, then
452	 * RGSR_EL1.SEED must be non-zero for IRG to produce
453	 * pseudorandom numbers. As RGSR_EL1 is UNKNOWN out of reset, we
454	 * must initialize it.
455	 */
456	mrs	x10, CNTVCT_EL0
457	ands	x10, x10, #SYS_RGSR_EL1_SEED_MASK
458	csinc	x10, x10, xzr, ne
459	lsl	x10, x10, #SYS_RGSR_EL1_SEED_SHIFT
460	msr_s	SYS_RGSR_EL1, x10
461
462	/* clear any pending tag check faults in TFSR*_EL1 */
463	msr_s	SYS_TFSR_EL1, xzr
464	msr_s	SYS_TFSRE0_EL1, xzr
465
466	/* set the TCR_EL1 bits */
467	mov_q	x10, TCR_KASAN_HW_FLAGS
468	orr	tcr, tcr, x10
4691:
470#endif
471	tcr_clear_errata_bits tcr, x9, x5
472
473#ifdef CONFIG_ARM64_VA_BITS_52
474	ldr_l		x9, vabits_actual
475	sub		x9, xzr, x9
476	add		x9, x9, #64
477	tcr_set_t1sz	tcr, x9
478#else
479	ldr_l		x9, idmap_t0sz
480#endif
481	tcr_set_t0sz	tcr, x9
482
483	/*
484	 * Set the IPS bits in TCR_EL1.
485	 */
486	tcr_compute_pa_size tcr, #TCR_IPS_SHIFT, x5, x6
487#ifdef CONFIG_ARM64_HW_AFDBM
488	/*
489	 * Enable hardware update of the Access Flags bit.
490	 * Hardware dirty bit management is enabled later,
491	 * via capabilities.
492	 */
493	mrs	x9, ID_AA64MMFR1_EL1
494	and	x9, x9, #0xf
495	cbz	x9, 1f
496	orr	tcr, tcr, #TCR_HA		// hardware Access flag update
4971:
498#endif	/* CONFIG_ARM64_HW_AFDBM */
499	msr	mair_el1, mair
500	msr	tcr_el1, tcr
501	/*
502	 * Prepare SCTLR
503	 */
504	mov_q	x0, INIT_SCTLR_EL1_MMU_ON
505	ret					// return to head.S
506
507	.unreq	mair
508	.unreq	tcr
509SYM_FUNC_END(__cpu_setup)
510