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82869ac5 JM |
1 | /*: |
2 | * Hibernate support specific for ARM64 | |
3 | * | |
4 | * Derived from work on ARM hibernation support by: | |
5 | * | |
6 | * Ubuntu project, hibernation support for mach-dove | |
7 | * Copyright (C) 2010 Nokia Corporation (Hiroshi Doyu) | |
8 | * Copyright (C) 2010 Texas Instruments, Inc. (Teerth Reddy et al.) | |
9 | * https://lkml.org/lkml/2010/6/18/4 | |
10 | * https://lists.linux-foundation.org/pipermail/linux-pm/2010-June/027422.html | |
11 | * https://patchwork.kernel.org/patch/96442/ | |
12 | * | |
13 | * Copyright (C) 2006 Rafael J. Wysocki <rjw@sisk.pl> | |
14 | * | |
15 | * License terms: GNU General Public License (GPL) version 2 | |
16 | */ | |
17 | #define pr_fmt(x) "hibernate: " x | |
8ec058fd | 18 | #include <linux/cpu.h> |
82869ac5 JM |
19 | #include <linux/kvm_host.h> |
20 | #include <linux/mm.h> | |
21 | #include <linux/pm.h> | |
22 | #include <linux/sched.h> | |
23 | #include <linux/suspend.h> | |
24 | #include <linux/utsname.h> | |
25 | #include <linux/version.h> | |
26 | ||
27 | #include <asm/barrier.h> | |
28 | #include <asm/cacheflush.h> | |
8ec058fd | 29 | #include <asm/cputype.h> |
82869ac5 JM |
30 | #include <asm/irqflags.h> |
31 | #include <asm/memory.h> | |
32 | #include <asm/mmu_context.h> | |
33 | #include <asm/pgalloc.h> | |
34 | #include <asm/pgtable.h> | |
35 | #include <asm/pgtable-hwdef.h> | |
36 | #include <asm/sections.h> | |
d74b4e4f | 37 | #include <asm/smp.h> |
8ec058fd | 38 | #include <asm/smp_plat.h> |
82869ac5 | 39 | #include <asm/suspend.h> |
0194e760 | 40 | #include <asm/sysreg.h> |
82869ac5 JM |
41 | #include <asm/virt.h> |
42 | ||
43 | /* | |
44 | * Hibernate core relies on this value being 0 on resume, and marks it | |
45 | * __nosavedata assuming it will keep the resume kernel's '0' value. This | |
46 | * doesn't happen with either KASLR. | |
47 | * | |
48 | * defined as "__visible int in_suspend __nosavedata" in | |
49 | * kernel/power/hibernate.c | |
50 | */ | |
51 | extern int in_suspend; | |
52 | ||
53 | /* Find a symbols alias in the linear map */ | |
54 | #define LMADDR(x) phys_to_virt(virt_to_phys(x)) | |
55 | ||
56 | /* Do we need to reset el2? */ | |
57 | #define el2_reset_needed() (is_hyp_mode_available() && !is_kernel_in_hyp_mode()) | |
58 | ||
82869ac5 JM |
59 | /* temporary el2 vectors in the __hibernate_exit_text section. */ |
60 | extern char hibernate_el2_vectors[]; | |
61 | ||
62 | /* hyp-stub vectors, used to restore el2 during resume from hibernate. */ | |
63 | extern char __hyp_stub_vectors[]; | |
64 | ||
8ec058fd JM |
65 | /* |
66 | * The logical cpu number we should resume on, initialised to a non-cpu | |
67 | * number. | |
68 | */ | |
69 | static int sleep_cpu = -EINVAL; | |
70 | ||
82869ac5 JM |
71 | /* |
72 | * Values that may not change over hibernate/resume. We put the build number | |
73 | * and date in here so that we guarantee not to resume with a different | |
74 | * kernel. | |
75 | */ | |
76 | struct arch_hibernate_hdr_invariants { | |
77 | char uts_version[__NEW_UTS_LEN + 1]; | |
78 | }; | |
79 | ||
80 | /* These values need to be know across a hibernate/restore. */ | |
81 | static struct arch_hibernate_hdr { | |
82 | struct arch_hibernate_hdr_invariants invariants; | |
83 | ||
84 | /* These are needed to find the relocated kernel if built with kaslr */ | |
85 | phys_addr_t ttbr1_el1; | |
86 | void (*reenter_kernel)(void); | |
87 | ||
88 | /* | |
89 | * We need to know where the __hyp_stub_vectors are after restore to | |
90 | * re-configure el2. | |
91 | */ | |
92 | phys_addr_t __hyp_stub_vectors; | |
8ec058fd JM |
93 | |
94 | u64 sleep_cpu_mpidr; | |
82869ac5 JM |
95 | } resume_hdr; |
96 | ||
97 | static inline void arch_hdr_invariants(struct arch_hibernate_hdr_invariants *i) | |
98 | { | |
99 | memset(i, 0, sizeof(*i)); | |
100 | memcpy(i->uts_version, init_utsname()->version, sizeof(i->uts_version)); | |
101 | } | |
102 | ||
103 | int pfn_is_nosave(unsigned long pfn) | |
104 | { | |
105 | unsigned long nosave_begin_pfn = virt_to_pfn(&__nosave_begin); | |
106 | unsigned long nosave_end_pfn = virt_to_pfn(&__nosave_end - 1); | |
107 | ||
108 | return (pfn >= nosave_begin_pfn) && (pfn <= nosave_end_pfn); | |
109 | } | |
110 | ||
111 | void notrace save_processor_state(void) | |
112 | { | |
113 | WARN_ON(num_online_cpus() != 1); | |
114 | } | |
115 | ||
116 | void notrace restore_processor_state(void) | |
117 | { | |
118 | } | |
119 | ||
120 | int arch_hibernation_header_save(void *addr, unsigned int max_size) | |
121 | { | |
122 | struct arch_hibernate_hdr *hdr = addr; | |
123 | ||
124 | if (max_size < sizeof(*hdr)) | |
125 | return -EOVERFLOW; | |
126 | ||
127 | arch_hdr_invariants(&hdr->invariants); | |
128 | hdr->ttbr1_el1 = virt_to_phys(swapper_pg_dir); | |
129 | hdr->reenter_kernel = _cpu_resume; | |
130 | ||
131 | /* We can't use __hyp_get_vectors() because kvm may still be loaded */ | |
132 | if (el2_reset_needed()) | |
133 | hdr->__hyp_stub_vectors = virt_to_phys(__hyp_stub_vectors); | |
134 | else | |
135 | hdr->__hyp_stub_vectors = 0; | |
136 | ||
8ec058fd JM |
137 | /* Save the mpidr of the cpu we called cpu_suspend() on... */ |
138 | if (sleep_cpu < 0) { | |
139 | pr_err("Failing to hibernate on an unkown CPU.\n"); | |
140 | return -ENODEV; | |
141 | } | |
142 | hdr->sleep_cpu_mpidr = cpu_logical_map(sleep_cpu); | |
143 | pr_info("Hibernating on CPU %d [mpidr:0x%llx]\n", sleep_cpu, | |
144 | hdr->sleep_cpu_mpidr); | |
145 | ||
82869ac5 JM |
146 | return 0; |
147 | } | |
148 | EXPORT_SYMBOL(arch_hibernation_header_save); | |
149 | ||
150 | int arch_hibernation_header_restore(void *addr) | |
151 | { | |
8ec058fd | 152 | int ret; |
82869ac5 JM |
153 | struct arch_hibernate_hdr_invariants invariants; |
154 | struct arch_hibernate_hdr *hdr = addr; | |
155 | ||
156 | arch_hdr_invariants(&invariants); | |
157 | if (memcmp(&hdr->invariants, &invariants, sizeof(invariants))) { | |
158 | pr_crit("Hibernate image not generated by this kernel!\n"); | |
159 | return -EINVAL; | |
160 | } | |
161 | ||
8ec058fd JM |
162 | sleep_cpu = get_logical_index(hdr->sleep_cpu_mpidr); |
163 | pr_info("Hibernated on CPU %d [mpidr:0x%llx]\n", sleep_cpu, | |
164 | hdr->sleep_cpu_mpidr); | |
165 | if (sleep_cpu < 0) { | |
166 | pr_crit("Hibernated on a CPU not known to this kernel!\n"); | |
167 | sleep_cpu = -EINVAL; | |
168 | return -EINVAL; | |
169 | } | |
170 | if (!cpu_online(sleep_cpu)) { | |
171 | pr_info("Hibernated on a CPU that is offline! Bringing CPU up.\n"); | |
172 | ret = cpu_up(sleep_cpu); | |
173 | if (ret) { | |
174 | pr_err("Failed to bring hibernate-CPU up!\n"); | |
175 | sleep_cpu = -EINVAL; | |
176 | return ret; | |
177 | } | |
178 | } | |
179 | ||
82869ac5 JM |
180 | resume_hdr = *hdr; |
181 | ||
182 | return 0; | |
183 | } | |
184 | EXPORT_SYMBOL(arch_hibernation_header_restore); | |
185 | ||
186 | /* | |
187 | * Copies length bytes, starting at src_start into an new page, | |
188 | * perform cache maintentance, then maps it at the specified address low | |
189 | * address as executable. | |
190 | * | |
191 | * This is used by hibernate to copy the code it needs to execute when | |
192 | * overwriting the kernel text. This function generates a new set of page | |
193 | * tables, which it loads into ttbr0. | |
194 | * | |
195 | * Length is provided as we probably only want 4K of data, even on a 64K | |
196 | * page system. | |
197 | */ | |
198 | static int create_safe_exec_page(void *src_start, size_t length, | |
199 | unsigned long dst_addr, | |
200 | phys_addr_t *phys_dst_addr, | |
201 | void *(*allocator)(gfp_t mask), | |
202 | gfp_t mask) | |
203 | { | |
204 | int rc = 0; | |
205 | pgd_t *pgd; | |
206 | pud_t *pud; | |
207 | pmd_t *pmd; | |
208 | pte_t *pte; | |
209 | unsigned long dst = (unsigned long)allocator(mask); | |
210 | ||
211 | if (!dst) { | |
212 | rc = -ENOMEM; | |
213 | goto out; | |
214 | } | |
215 | ||
216 | memcpy((void *)dst, src_start, length); | |
217 | flush_icache_range(dst, dst + length); | |
218 | ||
219 | pgd = pgd_offset_raw(allocator(mask), dst_addr); | |
220 | if (pgd_none(*pgd)) { | |
221 | pud = allocator(mask); | |
222 | if (!pud) { | |
223 | rc = -ENOMEM; | |
224 | goto out; | |
225 | } | |
226 | pgd_populate(&init_mm, pgd, pud); | |
227 | } | |
228 | ||
229 | pud = pud_offset(pgd, dst_addr); | |
230 | if (pud_none(*pud)) { | |
231 | pmd = allocator(mask); | |
232 | if (!pmd) { | |
233 | rc = -ENOMEM; | |
234 | goto out; | |
235 | } | |
236 | pud_populate(&init_mm, pud, pmd); | |
237 | } | |
238 | ||
239 | pmd = pmd_offset(pud, dst_addr); | |
240 | if (pmd_none(*pmd)) { | |
241 | pte = allocator(mask); | |
242 | if (!pte) { | |
243 | rc = -ENOMEM; | |
244 | goto out; | |
245 | } | |
246 | pmd_populate_kernel(&init_mm, pmd, pte); | |
247 | } | |
248 | ||
249 | pte = pte_offset_kernel(pmd, dst_addr); | |
250 | set_pte(pte, __pte(virt_to_phys((void *)dst) | | |
251 | pgprot_val(PAGE_KERNEL_EXEC))); | |
252 | ||
0194e760 MR |
253 | /* |
254 | * Load our new page tables. A strict BBM approach requires that we | |
255 | * ensure that TLBs are free of any entries that may overlap with the | |
256 | * global mappings we are about to install. | |
257 | * | |
258 | * For a real hibernate/resume cycle TTBR0 currently points to a zero | |
259 | * page, but TLBs may contain stale ASID-tagged entries (e.g. for EFI | |
260 | * runtime services), while for a userspace-driven test_resume cycle it | |
261 | * points to userspace page tables (and we must point it at a zero page | |
262 | * ourselves). Elsewhere we only (un)install the idmap with preemption | |
263 | * disabled, so T0SZ should be as required regardless. | |
264 | */ | |
265 | cpu_set_reserved_ttbr0(); | |
266 | local_flush_tlb_all(); | |
267 | write_sysreg(virt_to_phys(pgd), ttbr0_el1); | |
268 | isb(); | |
82869ac5 JM |
269 | |
270 | *phys_dst_addr = virt_to_phys((void *)dst); | |
271 | ||
272 | out: | |
273 | return rc; | |
274 | } | |
275 | ||
5ebe3a44 | 276 | #define dcache_clean_range(start, end) __flush_dcache_area(start, (end - start)) |
82869ac5 JM |
277 | |
278 | int swsusp_arch_suspend(void) | |
279 | { | |
280 | int ret = 0; | |
281 | unsigned long flags; | |
282 | struct sleep_stack_data state; | |
283 | ||
d74b4e4f JM |
284 | if (cpus_are_stuck_in_kernel()) { |
285 | pr_err("Can't hibernate: no mechanism to offline secondary CPUs.\n"); | |
286 | return -EBUSY; | |
287 | } | |
288 | ||
82869ac5 JM |
289 | local_dbg_save(flags); |
290 | ||
291 | if (__cpu_suspend_enter(&state)) { | |
8ec058fd | 292 | sleep_cpu = smp_processor_id(); |
82869ac5 JM |
293 | ret = swsusp_save(); |
294 | } else { | |
5ebe3a44 JM |
295 | /* Clean kernel core startup/idle code to PoC*/ |
296 | dcache_clean_range(__mmuoff_data_start, __mmuoff_data_end); | |
297 | dcache_clean_range(__idmap_text_start, __idmap_text_end); | |
298 | ||
299 | /* Clean kvm setup code to PoC? */ | |
300 | if (el2_reset_needed()) | |
301 | dcache_clean_range(__hyp_idmap_text_start, __hyp_idmap_text_end); | |
82869ac5 JM |
302 | |
303 | /* | |
304 | * Tell the hibernation core that we've just restored | |
305 | * the memory | |
306 | */ | |
307 | in_suspend = 0; | |
308 | ||
8ec058fd | 309 | sleep_cpu = -EINVAL; |
82869ac5 JM |
310 | __cpu_suspend_exit(); |
311 | } | |
312 | ||
313 | local_dbg_restore(flags); | |
314 | ||
315 | return ret; | |
316 | } | |
317 | ||
5ebe3a44 JM |
318 | static void _copy_pte(pte_t *dst_pte, pte_t *src_pte, unsigned long addr) |
319 | { | |
320 | pte_t pte = *src_pte; | |
321 | ||
322 | if (pte_valid(pte)) { | |
323 | /* | |
324 | * Resume will overwrite areas that may be marked | |
325 | * read only (code, rodata). Clear the RDONLY bit from | |
326 | * the temporary mappings we use during restore. | |
327 | */ | |
328 | set_pte(dst_pte, pte_clear_rdonly(pte)); | |
329 | } else if (debug_pagealloc_enabled() && !pte_none(pte)) { | |
330 | /* | |
331 | * debug_pagealloc will removed the PTE_VALID bit if | |
332 | * the page isn't in use by the resume kernel. It may have | |
333 | * been in use by the original kernel, in which case we need | |
334 | * to put it back in our copy to do the restore. | |
335 | * | |
336 | * Before marking this entry valid, check the pfn should | |
337 | * be mapped. | |
338 | */ | |
339 | BUG_ON(!pfn_valid(pte_pfn(pte))); | |
340 | ||
341 | set_pte(dst_pte, pte_mkpresent(pte_clear_rdonly(pte))); | |
342 | } | |
343 | } | |
344 | ||
82869ac5 JM |
345 | static int copy_pte(pmd_t *dst_pmd, pmd_t *src_pmd, unsigned long start, |
346 | unsigned long end) | |
347 | { | |
348 | pte_t *src_pte; | |
349 | pte_t *dst_pte; | |
350 | unsigned long addr = start; | |
351 | ||
352 | dst_pte = (pte_t *)get_safe_page(GFP_ATOMIC); | |
353 | if (!dst_pte) | |
354 | return -ENOMEM; | |
355 | pmd_populate_kernel(&init_mm, dst_pmd, dst_pte); | |
356 | dst_pte = pte_offset_kernel(dst_pmd, start); | |
357 | ||
358 | src_pte = pte_offset_kernel(src_pmd, start); | |
359 | do { | |
5ebe3a44 | 360 | _copy_pte(dst_pte, src_pte, addr); |
82869ac5 JM |
361 | } while (dst_pte++, src_pte++, addr += PAGE_SIZE, addr != end); |
362 | ||
363 | return 0; | |
364 | } | |
365 | ||
366 | static int copy_pmd(pud_t *dst_pud, pud_t *src_pud, unsigned long start, | |
367 | unsigned long end) | |
368 | { | |
369 | pmd_t *src_pmd; | |
370 | pmd_t *dst_pmd; | |
371 | unsigned long next; | |
372 | unsigned long addr = start; | |
373 | ||
374 | if (pud_none(*dst_pud)) { | |
375 | dst_pmd = (pmd_t *)get_safe_page(GFP_ATOMIC); | |
376 | if (!dst_pmd) | |
377 | return -ENOMEM; | |
378 | pud_populate(&init_mm, dst_pud, dst_pmd); | |
379 | } | |
380 | dst_pmd = pmd_offset(dst_pud, start); | |
381 | ||
382 | src_pmd = pmd_offset(src_pud, start); | |
383 | do { | |
384 | next = pmd_addr_end(addr, end); | |
385 | if (pmd_none(*src_pmd)) | |
386 | continue; | |
387 | if (pmd_table(*src_pmd)) { | |
388 | if (copy_pte(dst_pmd, src_pmd, addr, next)) | |
389 | return -ENOMEM; | |
390 | } else { | |
391 | set_pmd(dst_pmd, | |
392 | __pmd(pmd_val(*src_pmd) & ~PMD_SECT_RDONLY)); | |
393 | } | |
394 | } while (dst_pmd++, src_pmd++, addr = next, addr != end); | |
395 | ||
396 | return 0; | |
397 | } | |
398 | ||
399 | static int copy_pud(pgd_t *dst_pgd, pgd_t *src_pgd, unsigned long start, | |
400 | unsigned long end) | |
401 | { | |
402 | pud_t *dst_pud; | |
403 | pud_t *src_pud; | |
404 | unsigned long next; | |
405 | unsigned long addr = start; | |
406 | ||
407 | if (pgd_none(*dst_pgd)) { | |
408 | dst_pud = (pud_t *)get_safe_page(GFP_ATOMIC); | |
409 | if (!dst_pud) | |
410 | return -ENOMEM; | |
411 | pgd_populate(&init_mm, dst_pgd, dst_pud); | |
412 | } | |
413 | dst_pud = pud_offset(dst_pgd, start); | |
414 | ||
415 | src_pud = pud_offset(src_pgd, start); | |
416 | do { | |
417 | next = pud_addr_end(addr, end); | |
418 | if (pud_none(*src_pud)) | |
419 | continue; | |
420 | if (pud_table(*(src_pud))) { | |
421 | if (copy_pmd(dst_pud, src_pud, addr, next)) | |
422 | return -ENOMEM; | |
423 | } else { | |
424 | set_pud(dst_pud, | |
425 | __pud(pud_val(*src_pud) & ~PMD_SECT_RDONLY)); | |
426 | } | |
427 | } while (dst_pud++, src_pud++, addr = next, addr != end); | |
428 | ||
429 | return 0; | |
430 | } | |
431 | ||
432 | static int copy_page_tables(pgd_t *dst_pgd, unsigned long start, | |
433 | unsigned long end) | |
434 | { | |
435 | unsigned long next; | |
436 | unsigned long addr = start; | |
437 | pgd_t *src_pgd = pgd_offset_k(start); | |
438 | ||
439 | dst_pgd = pgd_offset_raw(dst_pgd, start); | |
440 | do { | |
441 | next = pgd_addr_end(addr, end); | |
442 | if (pgd_none(*src_pgd)) | |
443 | continue; | |
444 | if (copy_pud(dst_pgd, src_pgd, addr, next)) | |
445 | return -ENOMEM; | |
446 | } while (dst_pgd++, src_pgd++, addr = next, addr != end); | |
447 | ||
448 | return 0; | |
449 | } | |
450 | ||
451 | /* | |
452 | * Setup then Resume from the hibernate image using swsusp_arch_suspend_exit(). | |
453 | * | |
454 | * Memory allocated by get_safe_page() will be dealt with by the hibernate code, | |
455 | * we don't need to free it here. | |
456 | */ | |
457 | int swsusp_arch_resume(void) | |
458 | { | |
459 | int rc = 0; | |
460 | void *zero_page; | |
461 | size_t exit_size; | |
462 | pgd_t *tmp_pg_dir; | |
463 | void *lm_restore_pblist; | |
464 | phys_addr_t phys_hibernate_exit; | |
465 | void __noreturn (*hibernate_exit)(phys_addr_t, phys_addr_t, void *, | |
466 | void *, phys_addr_t, phys_addr_t); | |
467 | ||
dfbca61a MR |
468 | /* |
469 | * Restoring the memory image will overwrite the ttbr1 page tables. | |
470 | * Create a second copy of just the linear map, and use this when | |
471 | * restoring. | |
472 | */ | |
473 | tmp_pg_dir = (pgd_t *)get_safe_page(GFP_ATOMIC); | |
474 | if (!tmp_pg_dir) { | |
475 | pr_err("Failed to allocate memory for temporary page tables."); | |
476 | rc = -ENOMEM; | |
477 | goto out; | |
478 | } | |
479 | rc = copy_page_tables(tmp_pg_dir, PAGE_OFFSET, 0); | |
480 | if (rc) | |
481 | goto out; | |
482 | ||
483 | /* | |
484 | * Since we only copied the linear map, we need to find restore_pblist's | |
485 | * linear map address. | |
486 | */ | |
487 | lm_restore_pblist = LMADDR(restore_pblist); | |
488 | ||
489 | /* | |
490 | * We need a zero page that is zero before & after resume in order to | |
491 | * to break before make on the ttbr1 page tables. | |
492 | */ | |
493 | zero_page = (void *)get_safe_page(GFP_ATOMIC); | |
494 | if (!zero_page) { | |
495 | pr_err("Failed to allocate zero page."); | |
496 | rc = -ENOMEM; | |
497 | goto out; | |
498 | } | |
499 | ||
82869ac5 JM |
500 | /* |
501 | * Locate the exit code in the bottom-but-one page, so that *NULL | |
502 | * still has disastrous affects. | |
503 | */ | |
504 | hibernate_exit = (void *)PAGE_SIZE; | |
505 | exit_size = __hibernate_exit_text_end - __hibernate_exit_text_start; | |
506 | /* | |
507 | * Copy swsusp_arch_suspend_exit() to a safe page. This will generate | |
508 | * a new set of ttbr0 page tables and load them. | |
509 | */ | |
510 | rc = create_safe_exec_page(__hibernate_exit_text_start, exit_size, | |
511 | (unsigned long)hibernate_exit, | |
512 | &phys_hibernate_exit, | |
513 | (void *)get_safe_page, GFP_ATOMIC); | |
514 | if (rc) { | |
515 | pr_err("Failed to create safe executable page for hibernate_exit code."); | |
516 | goto out; | |
517 | } | |
518 | ||
519 | /* | |
520 | * The hibernate exit text contains a set of el2 vectors, that will | |
521 | * be executed at el2 with the mmu off in order to reload hyp-stub. | |
522 | */ | |
523 | __flush_dcache_area(hibernate_exit, exit_size); | |
524 | ||
82869ac5 JM |
525 | /* |
526 | * KASLR will cause the el2 vectors to be in a different location in | |
527 | * the resumed kernel. Load hibernate's temporary copy into el2. | |
528 | * | |
529 | * We can skip this step if we booted at EL1, or are running with VHE. | |
530 | */ | |
531 | if (el2_reset_needed()) { | |
532 | phys_addr_t el2_vectors = phys_hibernate_exit; /* base */ | |
533 | el2_vectors += hibernate_el2_vectors - | |
534 | __hibernate_exit_text_start; /* offset */ | |
535 | ||
536 | __hyp_set_vectors(el2_vectors); | |
537 | } | |
538 | ||
82869ac5 JM |
539 | hibernate_exit(virt_to_phys(tmp_pg_dir), resume_hdr.ttbr1_el1, |
540 | resume_hdr.reenter_kernel, lm_restore_pblist, | |
541 | resume_hdr.__hyp_stub_vectors, virt_to_phys(zero_page)); | |
542 | ||
543 | out: | |
544 | return rc; | |
545 | } | |
1fe492ce | 546 | |
8ec058fd JM |
547 | int hibernate_resume_nonboot_cpu_disable(void) |
548 | { | |
549 | if (sleep_cpu < 0) { | |
550 | pr_err("Failing to resume from hibernate on an unkown CPU.\n"); | |
551 | return -ENODEV; | |
552 | } | |
553 | ||
554 | return freeze_secondary_cpus(sleep_cpu); | |
555 | } |