1 // SPDX-License-Identifier: GPL-2.0-only
2 /*:
3 * Hibernate support specific for ARM64
4 *
5 * Derived from work on ARM hibernation support by:
6 *
7 * Ubuntu project, hibernation support for mach-dove
8 * Copyright (C) 2010 Nokia Corporation (Hiroshi Doyu)
9 * Copyright (C) 2010 Texas Instruments, Inc. (Teerth Reddy et al.)
10 * Copyright (C) 2006 Rafael J. Wysocki <rjw@sisk.pl>
11 */
12 #define pr_fmt(x) "hibernate: " x
13 #include <linux/cpu.h>
14 #include <linux/kvm_host.h>
15 #include <linux/pm.h>
16 #include <linux/sched.h>
17 #include <linux/suspend.h>
18 #include <linux/utsname.h>
19
20 #include <asm/barrier.h>
21 #include <asm/cacheflush.h>
22 #include <asm/cputype.h>
23 #include <asm/daifflags.h>
24 #include <asm/irqflags.h>
25 #include <asm/kexec.h>
26 #include <asm/memory.h>
27 #include <asm/mmu_context.h>
28 #include <asm/mte.h>
29 #include <asm/sections.h>
30 #include <asm/smp.h>
31 #include <asm/smp_plat.h>
32 #include <asm/suspend.h>
33 #include <asm/sysreg.h>
34 #include <asm/trans_pgd.h>
35 #include <asm/virt.h>
36
37 /*
38 * Hibernate core relies on this value being 0 on resume, and marks it
39 * __nosavedata assuming it will keep the resume kernel's '' value. This
40 * doesn't happen with either KASLR.
41 *
42 * defined as "__visible int in_suspend __nosavedata" in
43 * kernel/power/hibernate.c
44 */
45 extern int in_suspend;
46
47 /* Do we need to reset el2? */
48 #define el2_reset_needed() (is_hyp_nvhe())
49
50 /* hyp-stub vectors, used to restore el2 during resume from hibernate. */
51 extern char __hyp_stub_vectors[];
52
53 /*
54 * The logical cpu number we should resume on, initialised to a non-cpu
55 * number.
56 */
57 static int sleep_cpu = -EINVAL;
58
59 /*
60 * Values that may not change over hibernate/resume. We put the build number
61 * and date in here so that we guarantee not to resume with a different
62 * kernel.
63 */
64 struct arch_hibernate_hdr_invariants {
65 char uts_version[__NEW_UTS_LEN + 1];
66 };
67
68 /* These values need to be know across a hibernate/restore. */
69 static struct arch_hibernate_hdr {
70 struct arch_hibernate_hdr_invariants invariants;
71
72 /* These are needed to find the relocated kernel if built with kaslr */
73 phys_addr_t ttbr1_el1;
74 void (*reenter_kernel)(void);
75
76 /*
77 * We need to know where the __hyp_stub_vectors are after restore to
78 * re-configure el2.
79 */
80 phys_addr_t __hyp_stub_vectors;
81
82 u64 sleep_cpu_mpidr;
83 } resume_hdr;
84
85 static inline void arch_hdr_invariants(struct arch_hibernate_hdr_invariants *i)
86 {
87 memset(i, 0, sizeof(*i));
88 memcpy(i->uts_version, init_utsname()->version, sizeof(i->uts_version));
89 }
90
91 int pfn_is_nosave(unsigned long pfn)
92 {
93 unsigned long nosave_begin_pfn = sym_to_pfn(&__nosave_begin);
94 unsigned long nosave_end_pfn = sym_to_pfn(&__nosave_end - 1);
95
96 return ((pfn >= nosave_begin_pfn) && (pfn <= nosave_end_pfn)) ||
97 crash_is_nosave(pfn);
98 }
99
100 void notrace save_processor_state(void)
101 {
102 }
103
104 void notrace restore_processor_state(void)
105 {
106 }
107
108 int arch_hibernation_header_save(void *addr, unsigned int max_size)
109 {
110 struct arch_hibernate_hdr *hdr = addr;
111
112 if (max_size < sizeof(*hdr))
113 return -EOVERFLOW;
114
115 arch_hdr_invariants(&hdr->invariants);
116 hdr->ttbr1_el1 = __pa_symbol(swapper_pg_dir);
117 hdr->reenter_kernel = _cpu_resume;
118
119 /* We can't use __hyp_get_vectors() because kvm may still be loaded */
120 if (el2_reset_needed())
121 hdr->__hyp_stub_vectors = __pa_symbol(__hyp_stub_vectors);
122 else
123 hdr->__hyp_stub_vectors = 0;
124
125 /* Save the mpidr of the cpu we called cpu_suspend() on... */
126 if (sleep_cpu < 0) {
127 pr_err("Failing to hibernate on an unknown CPU.\n");
128 return -ENODEV;
129 }
130 hdr->sleep_cpu_mpidr = cpu_logical_map(sleep_cpu);
131 pr_info("Hibernating on CPU %d [mpidr:0x%llx]\n", sleep_cpu,
132 hdr->sleep_cpu_mpidr);
133
134 return 0;
135 }
136 EXPORT_SYMBOL(arch_hibernation_header_save);
137
138 int arch_hibernation_header_restore(void *addr)
139 {
140 int ret;
141 struct arch_hibernate_hdr_invariants invariants;
142 struct arch_hibernate_hdr *hdr = addr;
143
144 arch_hdr_invariants(&invariants);
145 if (memcmp(&hdr->invariants, &invariants, sizeof(invariants))) {
146 pr_crit("Hibernate image not generated by this kernel!\n");
147 return -EINVAL;
148 }
149
150 sleep_cpu = get_logical_index(hdr->sleep_cpu_mpidr);
151 pr_info("Hibernated on CPU %d [mpidr:0x%llx]\n", sleep_cpu,
152 hdr->sleep_cpu_mpidr);
153 if (sleep_cpu < 0) {
154 pr_crit("Hibernated on a CPU not known to this kernel!\n");
155 sleep_cpu = -EINVAL;
156 return -EINVAL;
157 }
158
159 ret = bringup_hibernate_cpu(sleep_cpu);
160 if (ret) {
161 sleep_cpu = -EINVAL;
162 return ret;
163 }
164
165 resume_hdr = *hdr;
166
167 return 0;
168 }
169 EXPORT_SYMBOL(arch_hibernation_header_restore);
170
171 static void *hibernate_page_alloc(void *arg)
172 {
173 return (void *)get_safe_page((__force gfp_t)(unsigned long)arg);
174 }
175
176 /*
177 * Copies length bytes, starting at src_start into an new page,
178 * perform cache maintenance, then maps it at the specified address low
179 * address as executable.
180 *
181 * This is used by hibernate to copy the code it needs to execute when
182 * overwriting the kernel text. This function generates a new set of page
183 * tables, which it loads into ttbr0.
184 *
185 * Length is provided as we probably only want 4K of data, even on a 64K
186 * page system.
187 */
188 static int create_safe_exec_page(void *src_start, size_t length,
189 phys_addr_t *phys_dst_addr)
190 {
191 struct trans_pgd_info trans_info = {
192 .trans_alloc_page = hibernate_page_alloc,
193 .trans_alloc_arg = (__force void *)GFP_ATOMIC,
194 };
195
196 void *page = (void *)get_safe_page(GFP_ATOMIC);
197 phys_addr_t trans_ttbr0;
198 unsigned long t0sz;
199 int rc;
200
201 if (!page)
202 return -ENOMEM;
203
204 memcpy(page, src_start, length);
205 caches_clean_inval_pou((unsigned long)page, (unsigned long)page + length);
206 rc = trans_pgd_idmap_page(&trans_info, &trans_ttbr0, &t0sz, page);
207 if (rc)
208 return rc;
209
210 cpu_install_ttbr0(trans_ttbr0, t0sz);
211 *phys_dst_addr = virt_to_phys(page);
212
213 return 0;
214 }
215
216 #ifdef CONFIG_ARM64_MTE
217
218 static DEFINE_XARRAY(mte_pages);
219
220 static int save_tags(struct page *page, unsigned long pfn)
221 {
222 void *tag_storage, *ret;
223
224 tag_storage = mte_allocate_tag_storage();
225 if (!tag_storage)
226 return -ENOMEM;
227
228 mte_save_page_tags(page_address(page), tag_storage);
229
230 ret = xa_store(&mte_pages, pfn, tag_storage, GFP_KERNEL);
231 if (WARN(xa_is_err(ret), "Failed to store MTE tags")) {
232 mte_free_tag_storage(tag_storage);
233 return xa_err(ret);
234 } else if (WARN(ret, "swsusp: %s: Duplicate entry", __func__)) {
235 mte_free_tag_storage(ret);
236 }
237
238 return 0;
239 }
240
241 static void swsusp_mte_free_storage(void)
242 {
243 XA_STATE(xa_state, &mte_pages, 0);
244 void *tags;
245
246 xa_lock(&mte_pages);
247 xas_for_each(&xa_state, tags, ULONG_MAX) {
248 mte_free_tag_storage(tags);
249 }
250 xa_unlock(&mte_pages);
251
252 xa_destroy(&mte_pages);
253 }
254
255 static int swsusp_mte_save_tags(void)
256 {
257 struct zone *zone;
258 unsigned long pfn, max_zone_pfn;
259 int ret = 0;
260 int n = 0;
261
262 if (!system_supports_mte())
263 return 0;
264
265 for_each_populated_zone(zone) {
266 max_zone_pfn = zone_end_pfn(zone);
267 for (pfn = zone->zone_start_pfn; pfn < max_zone_pfn; pfn++) {
268 struct page *page = pfn_to_online_page(pfn);
269
270 if (!page)
271 continue;
272
273 if (!page_mte_tagged(page))
274 continue;
275
276 ret = save_tags(page, pfn);
277 if (ret) {
278 swsusp_mte_free_storage();
279 goto out;
280 }
281
282 n++;
283 }
284 }
285 pr_info("Saved %d MTE pages\n", n);
286
287 out:
288 return ret;
289 }
290
291 static void swsusp_mte_restore_tags(void)
292 {
293 XA_STATE(xa_state, &mte_pages, 0);
294 int n = 0;
295 void *tags;
296
297 xa_lock(&mte_pages);
298 xas_for_each(&xa_state, tags, ULONG_MAX) {
299 unsigned long pfn = xa_state.xa_index;
300 struct page *page = pfn_to_online_page(pfn);
301
302 mte_restore_page_tags(page_address(page), tags);
303
304 mte_free_tag_storage(tags);
305 n++;
306 }
307 xa_unlock(&mte_pages);
308
309 pr_info("Restored %d MTE pages\n", n);
310
311 xa_destroy(&mte_pages);
312 }
313
314 #else /* CONFIG_ARM64_MTE */
315
316 static int swsusp_mte_save_tags(void)
317 {
318 return 0;
319 }
320
321 static void swsusp_mte_restore_tags(void)
322 {
323 }
324
325 #endif /* CONFIG_ARM64_MTE */
326
327 int swsusp_arch_suspend(void)
328 {
329 int ret = 0;
330 unsigned long flags;
331 struct sleep_stack_data state;
332
333 if (cpus_are_stuck_in_kernel()) {
334 pr_err("Can't hibernate: no mechanism to offline secondary CPUs.\n");
335 return -EBUSY;
336 }
337
338 flags = local_daif_save();
339
340 if (__cpu_suspend_enter(&state)) {
341 /* make the crash dump kernel image visible/saveable */
342 crash_prepare_suspend();
343
344 ret = swsusp_mte_save_tags();
345 if (ret)
346 return ret;
347
348 sleep_cpu = smp_processor_id();
349 ret = swsusp_save();
350 } else {
351 /* Clean kernel core startup/idle code to PoC*/
352 dcache_clean_inval_poc((unsigned long)__mmuoff_data_start,
353 (unsigned long)__mmuoff_data_end);
354 dcache_clean_inval_poc((unsigned long)__idmap_text_start,
355 (unsigned long)__idmap_text_end);
356
357 /* Clean kvm setup code to PoC? */
358 if (el2_reset_needed()) {
359 dcache_clean_inval_poc(
360 (unsigned long)__hyp_idmap_text_start,
361 (unsigned long)__hyp_idmap_text_end);
362 dcache_clean_inval_poc((unsigned long)__hyp_text_start,
363 (unsigned long)__hyp_text_end);
364 }
365
366 swsusp_mte_restore_tags();
367
368 /* make the crash dump kernel image protected again */
369 crash_post_resume();
370
371 /*
372 * Tell the hibernation core that we've just restored
373 * the memory
374 */
375 in_suspend = 0;
376
377 sleep_cpu = -EINVAL;
378 __cpu_suspend_exit();
379
380 /*
381 * Just in case the boot kernel did turn the SSBD
382 * mitigation off behind our back, let's set the state
383 * to what we expect it to be.
384 */
385 spectre_v4_enable_mitigation(NULL);
386 }
387
388 local_daif_restore(flags);
389
390 return ret;
391 }
392
393 /*
394 * Setup then Resume from the hibernate image using swsusp_arch_suspend_exit().
395 *
396 * Memory allocated by get_safe_page() will be dealt with by the hibernate code,
397 * we don't need to free it here.
398 */
399 int swsusp_arch_resume(void)
400 {
401 int rc;
402 void *zero_page;
403 size_t exit_size;
404 pgd_t *tmp_pg_dir;
405 phys_addr_t el2_vectors;
406 void __noreturn (*hibernate_exit)(phys_addr_t, phys_addr_t, void *,
407 void *, phys_addr_t, phys_addr_t);
408 struct trans_pgd_info trans_info = {
409 .trans_alloc_page = hibernate_page_alloc,
410 .trans_alloc_arg = (void *)GFP_ATOMIC,
411 };
412
413 /*
414 * Restoring the memory image will overwrite the ttbr1 page tables.
415 * Create a second copy of just the linear map, and use this when
416 * restoring.
417 */
418 rc = trans_pgd_create_copy(&trans_info, &tmp_pg_dir, PAGE_OFFSET,
419 PAGE_END);
420 if (rc)
421 return rc;
422
423 /*
424 * We need a zero page that is zero before & after resume in order
425 * to break before make on the ttbr1 page tables.
426 */
427 zero_page = (void *)get_safe_page(GFP_ATOMIC);
428 if (!zero_page) {
429 pr_err("Failed to allocate zero page.\n");
430 return -ENOMEM;
431 }
432
433 if (el2_reset_needed()) {
434 rc = trans_pgd_copy_el2_vectors(&trans_info, &el2_vectors);
435 if (rc) {
436 pr_err("Failed to setup el2 vectors\n");
437 return rc;
438 }
439 }
440
441 exit_size = __hibernate_exit_text_end - __hibernate_exit_text_start;
442 /*
443 * Copy swsusp_arch_suspend_exit() to a safe page. This will generate
444 * a new set of ttbr0 page tables and load them.
445 */
446 rc = create_safe_exec_page(__hibernate_exit_text_start, exit_size,
447 (phys_addr_t *)&hibernate_exit);
448 if (rc) {
449 pr_err("Failed to create safe executable page for hibernate_exit code.\n");
450 return rc;
451 }
452
453 /*
454 * KASLR will cause the el2 vectors to be in a different location in
455 * the resumed kernel. Load hibernate's temporary copy into el2.
456 *
457 * We can skip this step if we booted at EL1, or are running with VHE.
458 */
459 if (el2_reset_needed())
460 __hyp_set_vectors(el2_vectors);
461
462 hibernate_exit(virt_to_phys(tmp_pg_dir), resume_hdr.ttbr1_el1,
463 resume_hdr.reenter_kernel, restore_pblist,
464 resume_hdr.__hyp_stub_vectors, virt_to_phys(zero_page));
465
466 return 0;
467 }
468
469 int hibernate_resume_nonboot_cpu_disable(void)
470 {
471 if (sleep_cpu < 0) {
472 pr_err("Failing to resume from hibernate on an unknown CPU.\n");
473 return -ENODEV;
474 }
475
476 return freeze_secondary_cpus(sleep_cpu);
477 }
478
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