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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/cpu.h>
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>
29#include <asm/cputype.h>
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>
37#include <asm/smp.h>
38#include <asm/smp_plat.h>
39#include <asm/suspend.h>
40#include <asm/sysreg.h>
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 */
51extern 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
59/* temporary el2 vectors in the __hibernate_exit_text section. */
60extern char hibernate_el2_vectors[];
61
62/* hyp-stub vectors, used to restore el2 during resume from hibernate. */
63extern char __hyp_stub_vectors[];
64
65/*
66 * The logical cpu number we should resume on, initialised to a non-cpu
67 * number.
68 */
69static int sleep_cpu = -EINVAL;
70
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 */
76struct 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. */
81static 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;
93
94 u64 sleep_cpu_mpidr;
95} resume_hdr;
96
97static 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
103int 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
111void notrace save_processor_state(void)
112{
113 WARN_ON(num_online_cpus() != 1);
114}
115
116void notrace restore_processor_state(void)
117{
118}
119
120int 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
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 unknown 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
146 return 0;
147}
148EXPORT_SYMBOL(arch_hibernation_header_save);
149
150int arch_hibernation_header_restore(void *addr)
151{
152 int ret;
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
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
180 resume_hdr = *hdr;
181
182 return 0;
183}
184EXPORT_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 */
198static 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
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();
269
270 *phys_dst_addr = virt_to_phys((void *)dst);
271
272out:
273 return rc;
274}
275
276#define dcache_clean_range(start, end) __flush_dcache_area(start, (end - start))
277
278int swsusp_arch_suspend(void)
279{
280 int ret = 0;
281 unsigned long flags;
282 struct sleep_stack_data state;
283
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
289 local_dbg_save(flags);
290
291 if (__cpu_suspend_enter(&state)) {
292 sleep_cpu = smp_processor_id();
293 ret = swsusp_save();
294 } else {
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);
302
303 /*
304 * Tell the hibernation core that we've just restored
305 * the memory
306 */
307 in_suspend = 0;
308
309 sleep_cpu = -EINVAL;
310 __cpu_suspend_exit();
311 }
312
313 local_dbg_restore(flags);
314
315 return ret;
316}
317
318static 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
345static 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 {
360 _copy_pte(dst_pte, src_pte, addr);
361 } while (dst_pte++, src_pte++, addr += PAGE_SIZE, addr != end);
362
363 return 0;
364}
365
366static 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
399static 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
432static 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 */
457int 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
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
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
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
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
543out:
544 return rc;
545}
546
547int hibernate_resume_nonboot_cpu_disable(void)
548{
549 if (sleep_cpu < 0) {
550 pr_err("Failing to resume from hibernate on an unknown CPU.\n");
551 return -ENODEV;
552 }
553
554 return freeze_secondary_cpus(sleep_cpu);
555}