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/kvm_host.h>
21 #include <linux/sched.h>
22 #include <linux/suspend.h>
23 #include <linux/utsname.h>
24 #include <linux/version.h>
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>
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.
43 * defined as "__visible int in_suspend __nosavedata" in
44 * kernel/power/hibernate.c
46 extern int in_suspend;
48 /* Find a symbols alias in the linear map */
49 #define LMADDR(x) phys_to_virt(virt_to_phys(x))
51 /* Do we need to reset el2? */
52 #define el2_reset_needed() (is_hyp_mode_available() && !is_kernel_in_hyp_mode())
55 * Start/end of the hibernate exit code, this must be copied to a 'safe'
56 * location in memory, and executed from there.
58 extern char __hibernate_exit_text_start[], __hibernate_exit_text_end[];
60 /* temporary el2 vectors in the __hibernate_exit_text section. */
61 extern char hibernate_el2_vectors[];
63 /* hyp-stub vectors, used to restore el2 during resume from hibernate. */
64 extern char __hyp_stub_vectors[];
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
71 struct arch_hibernate_hdr_invariants {
72 char uts_version[__NEW_UTS_LEN + 1];
75 /* These values need to be know across a hibernate/restore. */
76 static struct arch_hibernate_hdr {
77 struct arch_hibernate_hdr_invariants invariants;
79 /* These are needed to find the relocated kernel if built with kaslr */
80 phys_addr_t ttbr1_el1;
81 void (*reenter_kernel)(void);
84 * We need to know where the __hyp_stub_vectors are after restore to
87 phys_addr_t __hyp_stub_vectors;
90 static inline void arch_hdr_invariants(struct arch_hibernate_hdr_invariants *i)
92 memset(i, 0, sizeof(*i));
93 memcpy(i->uts_version, init_utsname()->version, sizeof(i->uts_version));
96 int pfn_is_nosave(unsigned long pfn)
98 unsigned long nosave_begin_pfn = virt_to_pfn(&__nosave_begin);
99 unsigned long nosave_end_pfn = virt_to_pfn(&__nosave_end - 1);
101 return (pfn >= nosave_begin_pfn) && (pfn <= nosave_end_pfn);
104 void notrace save_processor_state(void)
106 WARN_ON(num_online_cpus() != 1);
109 void notrace restore_processor_state(void)
113 int arch_hibernation_header_save(void *addr, unsigned int max_size)
115 struct arch_hibernate_hdr *hdr = addr;
117 if (max_size < sizeof(*hdr))
120 arch_hdr_invariants(&hdr->invariants);
121 hdr->ttbr1_el1 = virt_to_phys(swapper_pg_dir);
122 hdr->reenter_kernel = _cpu_resume;
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);
128 hdr->__hyp_stub_vectors = 0;
132 EXPORT_SYMBOL(arch_hibernation_header_save);
134 int arch_hibernation_header_restore(void *addr)
136 struct arch_hibernate_hdr_invariants invariants;
137 struct arch_hibernate_hdr *hdr = addr;
139 arch_hdr_invariants(&invariants);
140 if (memcmp(&hdr->invariants, &invariants, sizeof(invariants))) {
141 pr_crit("Hibernate image not generated by this kernel!\n");
149 EXPORT_SYMBOL(arch_hibernation_header_restore);
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.
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.
160 * Length is provided as we probably only want 4K of data, even on a 64K
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),
174 unsigned long dst = (unsigned long)allocator(mask);
181 memcpy((void *)dst, src_start, length);
182 flush_icache_range(dst, dst + length);
184 pgd = pgd_offset_raw(allocator(mask), dst_addr);
185 if (pgd_none(*pgd)) {
186 pud = allocator(mask);
191 pgd_populate(&init_mm, pgd, pud);
194 pud = pud_offset(pgd, dst_addr);
195 if (pud_none(*pud)) {
196 pmd = allocator(mask);
201 pud_populate(&init_mm, pud, pmd);
204 pmd = pmd_offset(pud, dst_addr);
205 if (pmd_none(*pmd)) {
206 pte = allocator(mask);
211 pmd_populate_kernel(&init_mm, pmd, pte);
214 pte = pte_offset_kernel(pmd, dst_addr);
215 set_pte(pte, __pte(virt_to_phys((void *)dst) |
216 pgprot_val(PAGE_KERNEL_EXEC)));
218 /* Load our new page tables */
219 asm volatile("msr ttbr0_el1, %0;"
223 "isb" : : "r"(virt_to_phys(pgd)));
225 *phys_dst_addr = virt_to_phys((void *)dst);
232 int swsusp_arch_suspend(void)
236 struct sleep_stack_data state;
238 local_dbg_save(flags);
240 if (__cpu_suspend_enter(&state)) {
243 /* Clean kernel to PoC for secondary core startup */
244 __flush_dcache_area(LMADDR(KERNEL_START), KERNEL_END - KERNEL_START);
247 * Tell the hibernation core that we've just restored
252 __cpu_suspend_exit();
255 local_dbg_restore(flags);
260 static int copy_pte(pmd_t *dst_pmd, pmd_t *src_pmd, unsigned long start,
265 unsigned long addr = start;
267 dst_pte = (pte_t *)get_safe_page(GFP_ATOMIC);
270 pmd_populate_kernel(&init_mm, dst_pmd, dst_pte);
271 dst_pte = pte_offset_kernel(dst_pmd, start);
273 src_pte = pte_offset_kernel(src_pmd, start);
275 if (!pte_none(*src_pte))
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.
281 set_pte(dst_pte, __pte(pte_val(*src_pte) & ~PTE_RDONLY));
282 } while (dst_pte++, src_pte++, addr += PAGE_SIZE, addr != end);
287 static int copy_pmd(pud_t *dst_pud, pud_t *src_pud, unsigned long start,
293 unsigned long addr = start;
295 if (pud_none(*dst_pud)) {
296 dst_pmd = (pmd_t *)get_safe_page(GFP_ATOMIC);
299 pud_populate(&init_mm, dst_pud, dst_pmd);
301 dst_pmd = pmd_offset(dst_pud, start);
303 src_pmd = pmd_offset(src_pud, start);
305 next = pmd_addr_end(addr, end);
306 if (pmd_none(*src_pmd))
308 if (pmd_table(*src_pmd)) {
309 if (copy_pte(dst_pmd, src_pmd, addr, next))
313 __pmd(pmd_val(*src_pmd) & ~PMD_SECT_RDONLY));
315 } while (dst_pmd++, src_pmd++, addr = next, addr != end);
320 static int copy_pud(pgd_t *dst_pgd, pgd_t *src_pgd, unsigned long start,
326 unsigned long addr = start;
328 if (pgd_none(*dst_pgd)) {
329 dst_pud = (pud_t *)get_safe_page(GFP_ATOMIC);
332 pgd_populate(&init_mm, dst_pgd, dst_pud);
334 dst_pud = pud_offset(dst_pgd, start);
336 src_pud = pud_offset(src_pgd, start);
338 next = pud_addr_end(addr, end);
339 if (pud_none(*src_pud))
341 if (pud_table(*(src_pud))) {
342 if (copy_pmd(dst_pud, src_pud, addr, next))
346 __pud(pud_val(*src_pud) & ~PMD_SECT_RDONLY));
348 } while (dst_pud++, src_pud++, addr = next, addr != end);
353 static int copy_page_tables(pgd_t *dst_pgd, unsigned long start,
357 unsigned long addr = start;
358 pgd_t *src_pgd = pgd_offset_k(start);
360 dst_pgd = pgd_offset_raw(dst_pgd, start);
362 next = pgd_addr_end(addr, end);
363 if (pgd_none(*src_pgd))
365 if (copy_pud(dst_pgd, src_pgd, addr, next))
367 } while (dst_pgd++, src_pgd++, addr = next, addr != end);
373 * Setup then Resume from the hibernate image using swsusp_arch_suspend_exit().
375 * Memory allocated by get_safe_page() will be dealt with by the hibernate code,
376 * we don't need to free it here.
378 int swsusp_arch_resume(void)
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);
390 * Locate the exit code in the bottom-but-one page, so that *NULL
391 * still has disastrous affects.
393 hibernate_exit = (void *)PAGE_SIZE;
394 exit_size = __hibernate_exit_text_end - __hibernate_exit_text_start;
396 * Copy swsusp_arch_suspend_exit() to a safe page. This will generate
397 * a new set of ttbr0 page tables and load them.
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);
404 pr_err("Failed to create safe executable page for hibernate_exit code.");
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.
412 __flush_dcache_area(hibernate_exit, exit_size);
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
419 tmp_pg_dir = (pgd_t *)get_safe_page(GFP_ATOMIC);
421 pr_err("Failed to allocate memory for temporary page tables.");
425 rc = copy_page_tables(tmp_pg_dir, PAGE_OFFSET, 0);
430 * Since we only copied the linear map, we need to find restore_pblist's
431 * linear map address.
433 lm_restore_pblist = LMADDR(restore_pblist);
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.
439 * We can skip this step if we booted at EL1, or are running with VHE.
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 */
446 __hyp_set_vectors(el2_vectors);
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.
453 zero_page = (void *)get_safe_page(GFP_ATOMIC);
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));