2 * Hibernate support specific for ARM64
4 * Derived from work on ARM hibernation support by:
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/
13 * Copyright (C) 2006 Rafael J. Wysocki <rjw@sisk.pl>
15 * License terms: GNU General Public License (GPL) version 2
17 #define pr_fmt(x) "hibernate: " x
18 #include <linux/cpu.h>
19 #include <linux/kvm_host.h>
22 #include <linux/sched.h>
23 #include <linux/suspend.h>
24 #include <linux/utsname.h>
25 #include <linux/version.h>
27 #include <asm/barrier.h>
28 #include <asm/cacheflush.h>
29 #include <asm/cputype.h>
30 #include <asm/irqflags.h>
31 #include <asm/kexec.h>
32 #include <asm/memory.h>
33 #include <asm/mmu_context.h>
34 #include <asm/pgalloc.h>
35 #include <asm/pgtable.h>
36 #include <asm/pgtable-hwdef.h>
37 #include <asm/sections.h>
39 #include <asm/smp_plat.h>
40 #include <asm/suspend.h>
41 #include <asm/sysreg.h>
45 * Hibernate core relies on this value being 0 on resume, and marks it
46 * __nosavedata assuming it will keep the resume kernel's '0' value. This
47 * doesn't happen with either KASLR.
49 * defined as "__visible int in_suspend __nosavedata" in
50 * kernel/power/hibernate.c
52 extern int in_suspend;
54 /* Do we need to reset el2? */
55 #define el2_reset_needed() (is_hyp_mode_available() && !is_kernel_in_hyp_mode())
57 /* temporary el2 vectors in the __hibernate_exit_text section. */
58 extern char hibernate_el2_vectors[];
60 /* hyp-stub vectors, used to restore el2 during resume from hibernate. */
61 extern char __hyp_stub_vectors[];
64 * The logical cpu number we should resume on, initialised to a non-cpu
67 static int sleep_cpu = -EINVAL;
70 * Values that may not change over hibernate/resume. We put the build number
71 * and date in here so that we guarantee not to resume with a different
74 struct arch_hibernate_hdr_invariants {
75 char uts_version[__NEW_UTS_LEN + 1];
78 /* These values need to be know across a hibernate/restore. */
79 static struct arch_hibernate_hdr {
80 struct arch_hibernate_hdr_invariants invariants;
82 /* These are needed to find the relocated kernel if built with kaslr */
83 phys_addr_t ttbr1_el1;
84 void (*reenter_kernel)(void);
87 * We need to know where the __hyp_stub_vectors are after restore to
90 phys_addr_t __hyp_stub_vectors;
95 static inline void arch_hdr_invariants(struct arch_hibernate_hdr_invariants *i)
97 memset(i, 0, sizeof(*i));
98 memcpy(i->uts_version, init_utsname()->version, sizeof(i->uts_version));
101 int pfn_is_nosave(unsigned long pfn)
103 unsigned long nosave_begin_pfn = sym_to_pfn(&__nosave_begin);
104 unsigned long nosave_end_pfn = sym_to_pfn(&__nosave_end - 1);
106 return ((pfn >= nosave_begin_pfn) && (pfn <= nosave_end_pfn)) ||
107 crash_is_nosave(pfn);
110 void notrace save_processor_state(void)
112 WARN_ON(num_online_cpus() != 1);
115 void notrace restore_processor_state(void)
119 int arch_hibernation_header_save(void *addr, unsigned int max_size)
121 struct arch_hibernate_hdr *hdr = addr;
123 if (max_size < sizeof(*hdr))
126 arch_hdr_invariants(&hdr->invariants);
127 hdr->ttbr1_el1 = __pa_symbol(swapper_pg_dir);
128 hdr->reenter_kernel = _cpu_resume;
130 /* We can't use __hyp_get_vectors() because kvm may still be loaded */
131 if (el2_reset_needed())
132 hdr->__hyp_stub_vectors = __pa_symbol(__hyp_stub_vectors);
134 hdr->__hyp_stub_vectors = 0;
136 /* Save the mpidr of the cpu we called cpu_suspend() on... */
138 pr_err("Failing to hibernate on an unknown CPU.\n");
141 hdr->sleep_cpu_mpidr = cpu_logical_map(sleep_cpu);
142 pr_info("Hibernating on CPU %d [mpidr:0x%llx]\n", sleep_cpu,
143 hdr->sleep_cpu_mpidr);
147 EXPORT_SYMBOL(arch_hibernation_header_save);
149 int arch_hibernation_header_restore(void *addr)
152 struct arch_hibernate_hdr_invariants invariants;
153 struct arch_hibernate_hdr *hdr = addr;
155 arch_hdr_invariants(&invariants);
156 if (memcmp(&hdr->invariants, &invariants, sizeof(invariants))) {
157 pr_crit("Hibernate image not generated by this kernel!\n");
161 sleep_cpu = get_logical_index(hdr->sleep_cpu_mpidr);
162 pr_info("Hibernated on CPU %d [mpidr:0x%llx]\n", sleep_cpu,
163 hdr->sleep_cpu_mpidr);
165 pr_crit("Hibernated on a CPU not known to this kernel!\n");
169 if (!cpu_online(sleep_cpu)) {
170 pr_info("Hibernated on a CPU that is offline! Bringing CPU up.\n");
171 ret = cpu_up(sleep_cpu);
173 pr_err("Failed to bring hibernate-CPU up!\n");
183 EXPORT_SYMBOL(arch_hibernation_header_restore);
186 * Copies length bytes, starting at src_start into an new page,
187 * perform cache maintentance, then maps it at the specified address low
188 * address as executable.
190 * This is used by hibernate to copy the code it needs to execute when
191 * overwriting the kernel text. This function generates a new set of page
192 * tables, which it loads into ttbr0.
194 * Length is provided as we probably only want 4K of data, even on a 64K
197 static int create_safe_exec_page(void *src_start, size_t length,
198 unsigned long dst_addr,
199 phys_addr_t *phys_dst_addr,
200 void *(*allocator)(gfp_t mask),
208 unsigned long dst = (unsigned long)allocator(mask);
215 memcpy((void *)dst, src_start, length);
216 flush_icache_range(dst, dst + length);
218 pgd = pgd_offset_raw(allocator(mask), dst_addr);
219 if (pgd_none(*pgd)) {
220 pud = allocator(mask);
225 pgd_populate(&init_mm, pgd, pud);
228 pud = pud_offset(pgd, dst_addr);
229 if (pud_none(*pud)) {
230 pmd = allocator(mask);
235 pud_populate(&init_mm, pud, pmd);
238 pmd = pmd_offset(pud, dst_addr);
239 if (pmd_none(*pmd)) {
240 pte = allocator(mask);
245 pmd_populate_kernel(&init_mm, pmd, pte);
248 pte = pte_offset_kernel(pmd, dst_addr);
249 set_pte(pte, pfn_pte(virt_to_pfn(dst), PAGE_KERNEL_EXEC));
252 * Load our new page tables. A strict BBM approach requires that we
253 * ensure that TLBs are free of any entries that may overlap with the
254 * global mappings we are about to install.
256 * For a real hibernate/resume cycle TTBR0 currently points to a zero
257 * page, but TLBs may contain stale ASID-tagged entries (e.g. for EFI
258 * runtime services), while for a userspace-driven test_resume cycle it
259 * points to userspace page tables (and we must point it at a zero page
260 * ourselves). Elsewhere we only (un)install the idmap with preemption
261 * disabled, so T0SZ should be as required regardless.
263 cpu_set_reserved_ttbr0();
264 local_flush_tlb_all();
265 write_sysreg(virt_to_phys(pgd), ttbr0_el1);
268 *phys_dst_addr = virt_to_phys((void *)dst);
274 #define dcache_clean_range(start, end) __flush_dcache_area(start, (end - start))
276 int swsusp_arch_suspend(void)
280 struct sleep_stack_data state;
282 if (cpus_are_stuck_in_kernel()) {
283 pr_err("Can't hibernate: no mechanism to offline secondary CPUs.\n");
287 local_dbg_save(flags);
289 if (__cpu_suspend_enter(&state)) {
290 /* make the crash dump kernel image visible/saveable */
291 crash_prepare_suspend();
293 sleep_cpu = smp_processor_id();
296 /* Clean kernel core startup/idle code to PoC*/
297 dcache_clean_range(__mmuoff_data_start, __mmuoff_data_end);
298 dcache_clean_range(__idmap_text_start, __idmap_text_end);
300 /* Clean kvm setup code to PoC? */
301 if (el2_reset_needed()) {
302 dcache_clean_range(__hyp_idmap_text_start, __hyp_idmap_text_end);
303 dcache_clean_range(__hyp_text_start, __hyp_text_end);
306 /* make the crash dump kernel image protected again */
310 * Tell the hibernation core that we've just restored
316 __cpu_suspend_exit();
319 * Just in case the boot kernel did turn the SSBD
320 * mitigation off behind our back, let's set the state
321 * to what we expect it to be.
323 switch (arm64_get_ssbd_state()) {
324 case ARM64_SSBD_FORCE_ENABLE:
325 case ARM64_SSBD_KERNEL:
326 arm64_set_ssbd_mitigation(true);
330 local_dbg_restore(flags);
335 static void _copy_pte(pte_t *dst_pte, pte_t *src_pte, unsigned long addr)
337 pte_t pte = *src_pte;
339 if (pte_valid(pte)) {
341 * Resume will overwrite areas that may be marked
342 * read only (code, rodata). Clear the RDONLY bit from
343 * the temporary mappings we use during restore.
345 set_pte(dst_pte, pte_mkwrite(pte));
346 } else if (debug_pagealloc_enabled() && !pte_none(pte)) {
348 * debug_pagealloc will removed the PTE_VALID bit if
349 * the page isn't in use by the resume kernel. It may have
350 * been in use by the original kernel, in which case we need
351 * to put it back in our copy to do the restore.
353 * Before marking this entry valid, check the pfn should
356 BUG_ON(!pfn_valid(pte_pfn(pte)));
358 set_pte(dst_pte, pte_mkpresent(pte_mkwrite(pte)));
362 static int copy_pte(pmd_t *dst_pmd, pmd_t *src_pmd, unsigned long start,
367 unsigned long addr = start;
369 dst_pte = (pte_t *)get_safe_page(GFP_ATOMIC);
372 pmd_populate_kernel(&init_mm, dst_pmd, dst_pte);
373 dst_pte = pte_offset_kernel(dst_pmd, start);
375 src_pte = pte_offset_kernel(src_pmd, start);
377 _copy_pte(dst_pte, src_pte, addr);
378 } while (dst_pte++, src_pte++, addr += PAGE_SIZE, addr != end);
383 static int copy_pmd(pud_t *dst_pud, pud_t *src_pud, unsigned long start,
389 unsigned long addr = start;
391 if (pud_none(*dst_pud)) {
392 dst_pmd = (pmd_t *)get_safe_page(GFP_ATOMIC);
395 pud_populate(&init_mm, dst_pud, dst_pmd);
397 dst_pmd = pmd_offset(dst_pud, start);
399 src_pmd = pmd_offset(src_pud, start);
401 next = pmd_addr_end(addr, end);
402 if (pmd_none(*src_pmd))
404 if (pmd_table(*src_pmd)) {
405 if (copy_pte(dst_pmd, src_pmd, addr, next))
409 __pmd(pmd_val(*src_pmd) & ~PMD_SECT_RDONLY));
411 } while (dst_pmd++, src_pmd++, addr = next, addr != end);
416 static int copy_pud(pgd_t *dst_pgd, pgd_t *src_pgd, unsigned long start,
422 unsigned long addr = start;
424 if (pgd_none(*dst_pgd)) {
425 dst_pud = (pud_t *)get_safe_page(GFP_ATOMIC);
428 pgd_populate(&init_mm, dst_pgd, dst_pud);
430 dst_pud = pud_offset(dst_pgd, start);
432 src_pud = pud_offset(src_pgd, start);
434 next = pud_addr_end(addr, end);
435 if (pud_none(*src_pud))
437 if (pud_table(*(src_pud))) {
438 if (copy_pmd(dst_pud, src_pud, addr, next))
442 __pud(pud_val(*src_pud) & ~PMD_SECT_RDONLY));
444 } while (dst_pud++, src_pud++, addr = next, addr != end);
449 static int copy_page_tables(pgd_t *dst_pgd, unsigned long start,
453 unsigned long addr = start;
454 pgd_t *src_pgd = pgd_offset_k(start);
456 dst_pgd = pgd_offset_raw(dst_pgd, start);
458 next = pgd_addr_end(addr, end);
459 if (pgd_none(*src_pgd))
461 if (copy_pud(dst_pgd, src_pgd, addr, next))
463 } while (dst_pgd++, src_pgd++, addr = next, addr != end);
469 * Setup then Resume from the hibernate image using swsusp_arch_suspend_exit().
471 * Memory allocated by get_safe_page() will be dealt with by the hibernate code,
472 * we don't need to free it here.
474 int swsusp_arch_resume(void)
480 phys_addr_t phys_hibernate_exit;
481 void __noreturn (*hibernate_exit)(phys_addr_t, phys_addr_t, void *,
482 void *, phys_addr_t, phys_addr_t);
485 * Restoring the memory image will overwrite the ttbr1 page tables.
486 * Create a second copy of just the linear map, and use this when
489 tmp_pg_dir = (pgd_t *)get_safe_page(GFP_ATOMIC);
491 pr_err("Failed to allocate memory for temporary page tables.\n");
495 rc = copy_page_tables(tmp_pg_dir, PAGE_OFFSET, 0);
500 * We need a zero page that is zero before & after resume in order to
501 * to break before make on the ttbr1 page tables.
503 zero_page = (void *)get_safe_page(GFP_ATOMIC);
505 pr_err("Failed to allocate zero page.\n");
511 * Locate the exit code in the bottom-but-one page, so that *NULL
512 * still has disastrous affects.
514 hibernate_exit = (void *)PAGE_SIZE;
515 exit_size = __hibernate_exit_text_end - __hibernate_exit_text_start;
517 * Copy swsusp_arch_suspend_exit() to a safe page. This will generate
518 * a new set of ttbr0 page tables and load them.
520 rc = create_safe_exec_page(__hibernate_exit_text_start, exit_size,
521 (unsigned long)hibernate_exit,
522 &phys_hibernate_exit,
523 (void *)get_safe_page, GFP_ATOMIC);
525 pr_err("Failed to create safe executable page for hibernate_exit code.\n");
530 * The hibernate exit text contains a set of el2 vectors, that will
531 * be executed at el2 with the mmu off in order to reload hyp-stub.
533 __flush_dcache_area(hibernate_exit, exit_size);
536 * KASLR will cause the el2 vectors to be in a different location in
537 * the resumed kernel. Load hibernate's temporary copy into el2.
539 * We can skip this step if we booted at EL1, or are running with VHE.
541 if (el2_reset_needed()) {
542 phys_addr_t el2_vectors = phys_hibernate_exit; /* base */
543 el2_vectors += hibernate_el2_vectors -
544 __hibernate_exit_text_start; /* offset */
546 __hyp_set_vectors(el2_vectors);
549 hibernate_exit(virt_to_phys(tmp_pg_dir), resume_hdr.ttbr1_el1,
550 resume_hdr.reenter_kernel, restore_pblist,
551 resume_hdr.__hyp_stub_vectors, virt_to_phys(zero_page));
557 int hibernate_resume_nonboot_cpu_disable(void)
560 pr_err("Failing to resume from hibernate on an unknown CPU.\n");
564 return freeze_secondary_cpus(sleep_cpu);