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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 | |
18 | #include <linux/kvm_host.h> | |
19 | #include <linux/mm.h> | |
20 | #include <linux/pm.h> | |
21 | #include <linux/sched.h> | |
22 | #include <linux/suspend.h> | |
23 | #include <linux/utsname.h> | |
24 | #include <linux/version.h> | |
25 | ||
26 | #include <asm/barrier.h> | |
27 | #include <asm/cacheflush.h> | |
28 | #include <asm/irqflags.h> | |
29 | #include <asm/memory.h> | |
30 | #include <asm/mmu_context.h> | |
31 | #include <asm/pgalloc.h> | |
32 | #include <asm/pgtable.h> | |
33 | #include <asm/pgtable-hwdef.h> | |
34 | #include <asm/sections.h> | |
35 | #include <asm/suspend.h> | |
36 | #include <asm/virt.h> | |
37 | ||
38 | /* | |
39 | * Hibernate core relies on this value being 0 on resume, and marks it | |
40 | * __nosavedata assuming it will keep the resume kernel's '0' value. This | |
41 | * doesn't happen with either KASLR. | |
42 | * | |
43 | * defined as "__visible int in_suspend __nosavedata" in | |
44 | * kernel/power/hibernate.c | |
45 | */ | |
46 | extern int in_suspend; | |
47 | ||
48 | /* Find a symbols alias in the linear map */ | |
49 | #define LMADDR(x) phys_to_virt(virt_to_phys(x)) | |
50 | ||
51 | /* Do we need to reset el2? */ | |
52 | #define el2_reset_needed() (is_hyp_mode_available() && !is_kernel_in_hyp_mode()) | |
53 | ||
54 | /* | |
55 | * Start/end of the hibernate exit code, this must be copied to a 'safe' | |
56 | * location in memory, and executed from there. | |
57 | */ | |
58 | extern char __hibernate_exit_text_start[], __hibernate_exit_text_end[]; | |
59 | ||
60 | /* temporary el2 vectors in the __hibernate_exit_text section. */ | |
61 | extern char hibernate_el2_vectors[]; | |
62 | ||
63 | /* hyp-stub vectors, used to restore el2 during resume from hibernate. */ | |
64 | extern char __hyp_stub_vectors[]; | |
65 | ||
66 | /* | |
67 | * Values that may not change over hibernate/resume. We put the build number | |
68 | * and date in here so that we guarantee not to resume with a different | |
69 | * kernel. | |
70 | */ | |
71 | struct arch_hibernate_hdr_invariants { | |
72 | char uts_version[__NEW_UTS_LEN + 1]; | |
73 | }; | |
74 | ||
75 | /* These values need to be know across a hibernate/restore. */ | |
76 | static struct arch_hibernate_hdr { | |
77 | struct arch_hibernate_hdr_invariants invariants; | |
78 | ||
79 | /* These are needed to find the relocated kernel if built with kaslr */ | |
80 | phys_addr_t ttbr1_el1; | |
81 | void (*reenter_kernel)(void); | |
82 | ||
83 | /* | |
84 | * We need to know where the __hyp_stub_vectors are after restore to | |
85 | * re-configure el2. | |
86 | */ | |
87 | phys_addr_t __hyp_stub_vectors; | |
88 | } resume_hdr; | |
89 | ||
90 | static inline void arch_hdr_invariants(struct arch_hibernate_hdr_invariants *i) | |
91 | { | |
92 | memset(i, 0, sizeof(*i)); | |
93 | memcpy(i->uts_version, init_utsname()->version, sizeof(i->uts_version)); | |
94 | } | |
95 | ||
96 | int pfn_is_nosave(unsigned long pfn) | |
97 | { | |
98 | unsigned long nosave_begin_pfn = virt_to_pfn(&__nosave_begin); | |
99 | unsigned long nosave_end_pfn = virt_to_pfn(&__nosave_end - 1); | |
100 | ||
101 | return (pfn >= nosave_begin_pfn) && (pfn <= nosave_end_pfn); | |
102 | } | |
103 | ||
104 | void notrace save_processor_state(void) | |
105 | { | |
106 | WARN_ON(num_online_cpus() != 1); | |
107 | } | |
108 | ||
109 | void notrace restore_processor_state(void) | |
110 | { | |
111 | } | |
112 | ||
113 | int arch_hibernation_header_save(void *addr, unsigned int max_size) | |
114 | { | |
115 | struct arch_hibernate_hdr *hdr = addr; | |
116 | ||
117 | if (max_size < sizeof(*hdr)) | |
118 | return -EOVERFLOW; | |
119 | ||
120 | arch_hdr_invariants(&hdr->invariants); | |
121 | hdr->ttbr1_el1 = virt_to_phys(swapper_pg_dir); | |
122 | hdr->reenter_kernel = _cpu_resume; | |
123 | ||
124 | /* We can't use __hyp_get_vectors() because kvm may still be loaded */ | |
125 | if (el2_reset_needed()) | |
126 | hdr->__hyp_stub_vectors = virt_to_phys(__hyp_stub_vectors); | |
127 | else | |
128 | hdr->__hyp_stub_vectors = 0; | |
129 | ||
130 | return 0; | |
131 | } | |
132 | EXPORT_SYMBOL(arch_hibernation_header_save); | |
133 | ||
134 | int arch_hibernation_header_restore(void *addr) | |
135 | { | |
136 | struct arch_hibernate_hdr_invariants invariants; | |
137 | struct arch_hibernate_hdr *hdr = addr; | |
138 | ||
139 | arch_hdr_invariants(&invariants); | |
140 | if (memcmp(&hdr->invariants, &invariants, sizeof(invariants))) { | |
141 | pr_crit("Hibernate image not generated by this kernel!\n"); | |
142 | return -EINVAL; | |
143 | } | |
144 | ||
145 | resume_hdr = *hdr; | |
146 | ||
147 | return 0; | |
148 | } | |
149 | EXPORT_SYMBOL(arch_hibernation_header_restore); | |
150 | ||
151 | /* | |
152 | * Copies length bytes, starting at src_start into an new page, | |
153 | * perform cache maintentance, then maps it at the specified address low | |
154 | * address as executable. | |
155 | * | |
156 | * This is used by hibernate to copy the code it needs to execute when | |
157 | * overwriting the kernel text. This function generates a new set of page | |
158 | * tables, which it loads into ttbr0. | |
159 | * | |
160 | * Length is provided as we probably only want 4K of data, even on a 64K | |
161 | * page system. | |
162 | */ | |
163 | static int create_safe_exec_page(void *src_start, size_t length, | |
164 | unsigned long dst_addr, | |
165 | phys_addr_t *phys_dst_addr, | |
166 | void *(*allocator)(gfp_t mask), | |
167 | gfp_t mask) | |
168 | { | |
169 | int rc = 0; | |
170 | pgd_t *pgd; | |
171 | pud_t *pud; | |
172 | pmd_t *pmd; | |
173 | pte_t *pte; | |
174 | unsigned long dst = (unsigned long)allocator(mask); | |
175 | ||
176 | if (!dst) { | |
177 | rc = -ENOMEM; | |
178 | goto out; | |
179 | } | |
180 | ||
181 | memcpy((void *)dst, src_start, length); | |
182 | flush_icache_range(dst, dst + length); | |
183 | ||
184 | pgd = pgd_offset_raw(allocator(mask), dst_addr); | |
185 | if (pgd_none(*pgd)) { | |
186 | pud = allocator(mask); | |
187 | if (!pud) { | |
188 | rc = -ENOMEM; | |
189 | goto out; | |
190 | } | |
191 | pgd_populate(&init_mm, pgd, pud); | |
192 | } | |
193 | ||
194 | pud = pud_offset(pgd, dst_addr); | |
195 | if (pud_none(*pud)) { | |
196 | pmd = allocator(mask); | |
197 | if (!pmd) { | |
198 | rc = -ENOMEM; | |
199 | goto out; | |
200 | } | |
201 | pud_populate(&init_mm, pud, pmd); | |
202 | } | |
203 | ||
204 | pmd = pmd_offset(pud, dst_addr); | |
205 | if (pmd_none(*pmd)) { | |
206 | pte = allocator(mask); | |
207 | if (!pte) { | |
208 | rc = -ENOMEM; | |
209 | goto out; | |
210 | } | |
211 | pmd_populate_kernel(&init_mm, pmd, pte); | |
212 | } | |
213 | ||
214 | pte = pte_offset_kernel(pmd, dst_addr); | |
215 | set_pte(pte, __pte(virt_to_phys((void *)dst) | | |
216 | pgprot_val(PAGE_KERNEL_EXEC))); | |
217 | ||
218 | /* Load our new page tables */ | |
219 | asm volatile("msr ttbr0_el1, %0;" | |
220 | "isb;" | |
221 | "tlbi vmalle1is;" | |
222 | "dsb ish;" | |
223 | "isb" : : "r"(virt_to_phys(pgd))); | |
224 | ||
225 | *phys_dst_addr = virt_to_phys((void *)dst); | |
226 | ||
227 | out: | |
228 | return rc; | |
229 | } | |
230 | ||
231 | ||
232 | int swsusp_arch_suspend(void) | |
233 | { | |
234 | int ret = 0; | |
235 | unsigned long flags; | |
236 | struct sleep_stack_data state; | |
237 | ||
238 | local_dbg_save(flags); | |
239 | ||
240 | if (__cpu_suspend_enter(&state)) { | |
241 | ret = swsusp_save(); | |
242 | } else { | |
243 | /* Clean kernel to PoC for secondary core startup */ | |
244 | __flush_dcache_area(LMADDR(KERNEL_START), KERNEL_END - KERNEL_START); | |
245 | ||
246 | /* | |
247 | * Tell the hibernation core that we've just restored | |
248 | * the memory | |
249 | */ | |
250 | in_suspend = 0; | |
251 | ||
252 | __cpu_suspend_exit(); | |
253 | } | |
254 | ||
255 | local_dbg_restore(flags); | |
256 | ||
257 | return ret; | |
258 | } | |
259 | ||
260 | static int copy_pte(pmd_t *dst_pmd, pmd_t *src_pmd, unsigned long start, | |
261 | unsigned long end) | |
262 | { | |
263 | pte_t *src_pte; | |
264 | pte_t *dst_pte; | |
265 | unsigned long addr = start; | |
266 | ||
267 | dst_pte = (pte_t *)get_safe_page(GFP_ATOMIC); | |
268 | if (!dst_pte) | |
269 | return -ENOMEM; | |
270 | pmd_populate_kernel(&init_mm, dst_pmd, dst_pte); | |
271 | dst_pte = pte_offset_kernel(dst_pmd, start); | |
272 | ||
273 | src_pte = pte_offset_kernel(src_pmd, start); | |
274 | do { | |
275 | if (!pte_none(*src_pte)) | |
276 | /* | |
277 | * Resume will overwrite areas that may be marked | |
278 | * read only (code, rodata). Clear the RDONLY bit from | |
279 | * the temporary mappings we use during restore. | |
280 | */ | |
281 | set_pte(dst_pte, __pte(pte_val(*src_pte) & ~PTE_RDONLY)); | |
282 | } while (dst_pte++, src_pte++, addr += PAGE_SIZE, addr != end); | |
283 | ||
284 | return 0; | |
285 | } | |
286 | ||
287 | static int copy_pmd(pud_t *dst_pud, pud_t *src_pud, unsigned long start, | |
288 | unsigned long end) | |
289 | { | |
290 | pmd_t *src_pmd; | |
291 | pmd_t *dst_pmd; | |
292 | unsigned long next; | |
293 | unsigned long addr = start; | |
294 | ||
295 | if (pud_none(*dst_pud)) { | |
296 | dst_pmd = (pmd_t *)get_safe_page(GFP_ATOMIC); | |
297 | if (!dst_pmd) | |
298 | return -ENOMEM; | |
299 | pud_populate(&init_mm, dst_pud, dst_pmd); | |
300 | } | |
301 | dst_pmd = pmd_offset(dst_pud, start); | |
302 | ||
303 | src_pmd = pmd_offset(src_pud, start); | |
304 | do { | |
305 | next = pmd_addr_end(addr, end); | |
306 | if (pmd_none(*src_pmd)) | |
307 | continue; | |
308 | if (pmd_table(*src_pmd)) { | |
309 | if (copy_pte(dst_pmd, src_pmd, addr, next)) | |
310 | return -ENOMEM; | |
311 | } else { | |
312 | set_pmd(dst_pmd, | |
313 | __pmd(pmd_val(*src_pmd) & ~PMD_SECT_RDONLY)); | |
314 | } | |
315 | } while (dst_pmd++, src_pmd++, addr = next, addr != end); | |
316 | ||
317 | return 0; | |
318 | } | |
319 | ||
320 | static int copy_pud(pgd_t *dst_pgd, pgd_t *src_pgd, unsigned long start, | |
321 | unsigned long end) | |
322 | { | |
323 | pud_t *dst_pud; | |
324 | pud_t *src_pud; | |
325 | unsigned long next; | |
326 | unsigned long addr = start; | |
327 | ||
328 | if (pgd_none(*dst_pgd)) { | |
329 | dst_pud = (pud_t *)get_safe_page(GFP_ATOMIC); | |
330 | if (!dst_pud) | |
331 | return -ENOMEM; | |
332 | pgd_populate(&init_mm, dst_pgd, dst_pud); | |
333 | } | |
334 | dst_pud = pud_offset(dst_pgd, start); | |
335 | ||
336 | src_pud = pud_offset(src_pgd, start); | |
337 | do { | |
338 | next = pud_addr_end(addr, end); | |
339 | if (pud_none(*src_pud)) | |
340 | continue; | |
341 | if (pud_table(*(src_pud))) { | |
342 | if (copy_pmd(dst_pud, src_pud, addr, next)) | |
343 | return -ENOMEM; | |
344 | } else { | |
345 | set_pud(dst_pud, | |
346 | __pud(pud_val(*src_pud) & ~PMD_SECT_RDONLY)); | |
347 | } | |
348 | } while (dst_pud++, src_pud++, addr = next, addr != end); | |
349 | ||
350 | return 0; | |
351 | } | |
352 | ||
353 | static int copy_page_tables(pgd_t *dst_pgd, unsigned long start, | |
354 | unsigned long end) | |
355 | { | |
356 | unsigned long next; | |
357 | unsigned long addr = start; | |
358 | pgd_t *src_pgd = pgd_offset_k(start); | |
359 | ||
360 | dst_pgd = pgd_offset_raw(dst_pgd, start); | |
361 | do { | |
362 | next = pgd_addr_end(addr, end); | |
363 | if (pgd_none(*src_pgd)) | |
364 | continue; | |
365 | if (copy_pud(dst_pgd, src_pgd, addr, next)) | |
366 | return -ENOMEM; | |
367 | } while (dst_pgd++, src_pgd++, addr = next, addr != end); | |
368 | ||
369 | return 0; | |
370 | } | |
371 | ||
372 | /* | |
373 | * Setup then Resume from the hibernate image using swsusp_arch_suspend_exit(). | |
374 | * | |
375 | * Memory allocated by get_safe_page() will be dealt with by the hibernate code, | |
376 | * we don't need to free it here. | |
377 | */ | |
378 | int swsusp_arch_resume(void) | |
379 | { | |
380 | int rc = 0; | |
381 | void *zero_page; | |
382 | size_t exit_size; | |
383 | pgd_t *tmp_pg_dir; | |
384 | void *lm_restore_pblist; | |
385 | phys_addr_t phys_hibernate_exit; | |
386 | void __noreturn (*hibernate_exit)(phys_addr_t, phys_addr_t, void *, | |
387 | void *, phys_addr_t, phys_addr_t); | |
388 | ||
389 | /* | |
390 | * Locate the exit code in the bottom-but-one page, so that *NULL | |
391 | * still has disastrous affects. | |
392 | */ | |
393 | hibernate_exit = (void *)PAGE_SIZE; | |
394 | exit_size = __hibernate_exit_text_end - __hibernate_exit_text_start; | |
395 | /* | |
396 | * Copy swsusp_arch_suspend_exit() to a safe page. This will generate | |
397 | * a new set of ttbr0 page tables and load them. | |
398 | */ | |
399 | rc = create_safe_exec_page(__hibernate_exit_text_start, exit_size, | |
400 | (unsigned long)hibernate_exit, | |
401 | &phys_hibernate_exit, | |
402 | (void *)get_safe_page, GFP_ATOMIC); | |
403 | if (rc) { | |
404 | pr_err("Failed to create safe executable page for hibernate_exit code."); | |
405 | goto out; | |
406 | } | |
407 | ||
408 | /* | |
409 | * The hibernate exit text contains a set of el2 vectors, that will | |
410 | * be executed at el2 with the mmu off in order to reload hyp-stub. | |
411 | */ | |
412 | __flush_dcache_area(hibernate_exit, exit_size); | |
413 | ||
414 | /* | |
415 | * Restoring the memory image will overwrite the ttbr1 page tables. | |
416 | * Create a second copy of just the linear map, and use this when | |
417 | * restoring. | |
418 | */ | |
419 | tmp_pg_dir = (pgd_t *)get_safe_page(GFP_ATOMIC); | |
420 | if (!tmp_pg_dir) { | |
421 | pr_err("Failed to allocate memory for temporary page tables."); | |
422 | rc = -ENOMEM; | |
423 | goto out; | |
424 | } | |
425 | rc = copy_page_tables(tmp_pg_dir, PAGE_OFFSET, 0); | |
426 | if (rc) | |
427 | goto out; | |
428 | ||
429 | /* | |
430 | * Since we only copied the linear map, we need to find restore_pblist's | |
431 | * linear map address. | |
432 | */ | |
433 | lm_restore_pblist = LMADDR(restore_pblist); | |
434 | ||
435 | /* | |
436 | * KASLR will cause the el2 vectors to be in a different location in | |
437 | * the resumed kernel. Load hibernate's temporary copy into el2. | |
438 | * | |
439 | * We can skip this step if we booted at EL1, or are running with VHE. | |
440 | */ | |
441 | if (el2_reset_needed()) { | |
442 | phys_addr_t el2_vectors = phys_hibernate_exit; /* base */ | |
443 | el2_vectors += hibernate_el2_vectors - | |
444 | __hibernate_exit_text_start; /* offset */ | |
445 | ||
446 | __hyp_set_vectors(el2_vectors); | |
447 | } | |
448 | ||
449 | /* | |
450 | * We need a zero page that is zero before & after resume in order to | |
451 | * to break before make on the ttbr1 page tables. | |
452 | */ | |
453 | zero_page = (void *)get_safe_page(GFP_ATOMIC); | |
454 | ||
455 | hibernate_exit(virt_to_phys(tmp_pg_dir), resume_hdr.ttbr1_el1, | |
456 | resume_hdr.reenter_kernel, lm_restore_pblist, | |
457 | resume_hdr.__hyp_stub_vectors, virt_to_phys(zero_page)); | |
458 | ||
459 | out: | |
460 | return rc; | |
461 | } |