xref: /linux/arch/x86/power/hibernate_64.c (revision bab2c80e5a6c855657482eac9e97f5f3eedb509a)
1 /*
2  * Hibernation support for x86-64
3  *
4  * Distribute under GPLv2
5  *
6  * Copyright (c) 2007 Rafael J. Wysocki <rjw@sisk.pl>
7  * Copyright (c) 2002 Pavel Machek <pavel@ucw.cz>
8  * Copyright (c) 2001 Patrick Mochel <mochel@osdl.org>
9  */
10 
11 #include <linux/gfp.h>
12 #include <linux/smp.h>
13 #include <linux/suspend.h>
14 #include <linux/scatterlist.h>
15 #include <linux/kdebug.h>
16 
17 #include <crypto/hash.h>
18 
19 #include <asm/e820/api.h>
20 #include <asm/init.h>
21 #include <asm/proto.h>
22 #include <asm/page.h>
23 #include <asm/pgtable.h>
24 #include <asm/mtrr.h>
25 #include <asm/sections.h>
26 #include <asm/suspend.h>
27 #include <asm/tlbflush.h>
28 
29 /* Defined in hibernate_asm_64.S */
30 extern asmlinkage __visible int restore_image(void);
31 
32 /*
33  * Address to jump to in the last phase of restore in order to get to the image
34  * kernel's text (this value is passed in the image header).
35  */
36 unsigned long restore_jump_address __visible;
37 unsigned long jump_address_phys;
38 
39 /*
40  * Value of the cr3 register from before the hibernation (this value is passed
41  * in the image header).
42  */
43 unsigned long restore_cr3 __visible;
44 
45 unsigned long temp_level4_pgt __visible;
46 
47 unsigned long relocated_restore_code __visible;
48 
49 static int set_up_temporary_text_mapping(pgd_t *pgd)
50 {
51 	pmd_t *pmd;
52 	pud_t *pud;
53 	p4d_t *p4d = NULL;
54 	pgprot_t pgtable_prot = __pgprot(_KERNPG_TABLE);
55 	pgprot_t pmd_text_prot = __pgprot(__PAGE_KERNEL_LARGE_EXEC);
56 
57 	/* Filter out unsupported __PAGE_KERNEL* bits: */
58 	pgprot_val(pmd_text_prot) &= __default_kernel_pte_mask;
59 	pgprot_val(pgtable_prot)  &= __default_kernel_pte_mask;
60 
61 	/*
62 	 * The new mapping only has to cover the page containing the image
63 	 * kernel's entry point (jump_address_phys), because the switch over to
64 	 * it is carried out by relocated code running from a page allocated
65 	 * specifically for this purpose and covered by the identity mapping, so
66 	 * the temporary kernel text mapping is only needed for the final jump.
67 	 * Moreover, in that mapping the virtual address of the image kernel's
68 	 * entry point must be the same as its virtual address in the image
69 	 * kernel (restore_jump_address), so the image kernel's
70 	 * restore_registers() code doesn't find itself in a different area of
71 	 * the virtual address space after switching over to the original page
72 	 * tables used by the image kernel.
73 	 */
74 
75 	if (pgtable_l5_enabled()) {
76 		p4d = (p4d_t *)get_safe_page(GFP_ATOMIC);
77 		if (!p4d)
78 			return -ENOMEM;
79 	}
80 
81 	pud = (pud_t *)get_safe_page(GFP_ATOMIC);
82 	if (!pud)
83 		return -ENOMEM;
84 
85 	pmd = (pmd_t *)get_safe_page(GFP_ATOMIC);
86 	if (!pmd)
87 		return -ENOMEM;
88 
89 	set_pmd(pmd + pmd_index(restore_jump_address),
90 		__pmd((jump_address_phys & PMD_MASK) | pgprot_val(pmd_text_prot)));
91 	set_pud(pud + pud_index(restore_jump_address),
92 		__pud(__pa(pmd) | pgprot_val(pgtable_prot)));
93 	if (p4d) {
94 		p4d_t new_p4d = __p4d(__pa(pud) | pgprot_val(pgtable_prot));
95 		pgd_t new_pgd = __pgd(__pa(p4d) | pgprot_val(pgtable_prot));
96 
97 		set_p4d(p4d + p4d_index(restore_jump_address), new_p4d);
98 		set_pgd(pgd + pgd_index(restore_jump_address), new_pgd);
99 	} else {
100 		/* No p4d for 4-level paging: point the pgd to the pud page table */
101 		pgd_t new_pgd = __pgd(__pa(pud) | pgprot_val(pgtable_prot));
102 		set_pgd(pgd + pgd_index(restore_jump_address), new_pgd);
103 	}
104 
105 	return 0;
106 }
107 
108 static void *alloc_pgt_page(void *context)
109 {
110 	return (void *)get_safe_page(GFP_ATOMIC);
111 }
112 
113 static int set_up_temporary_mappings(void)
114 {
115 	struct x86_mapping_info info = {
116 		.alloc_pgt_page	= alloc_pgt_page,
117 		.page_flag	= __PAGE_KERNEL_LARGE_EXEC,
118 		.offset		= __PAGE_OFFSET,
119 	};
120 	unsigned long mstart, mend;
121 	pgd_t *pgd;
122 	int result;
123 	int i;
124 
125 	pgd = (pgd_t *)get_safe_page(GFP_ATOMIC);
126 	if (!pgd)
127 		return -ENOMEM;
128 
129 	/* Prepare a temporary mapping for the kernel text */
130 	result = set_up_temporary_text_mapping(pgd);
131 	if (result)
132 		return result;
133 
134 	/* Set up the direct mapping from scratch */
135 	for (i = 0; i < nr_pfn_mapped; i++) {
136 		mstart = pfn_mapped[i].start << PAGE_SHIFT;
137 		mend   = pfn_mapped[i].end << PAGE_SHIFT;
138 
139 		result = kernel_ident_mapping_init(&info, pgd, mstart, mend);
140 		if (result)
141 			return result;
142 	}
143 
144 	temp_level4_pgt = __pa(pgd);
145 	return 0;
146 }
147 
148 static int relocate_restore_code(void)
149 {
150 	pgd_t *pgd;
151 	p4d_t *p4d;
152 	pud_t *pud;
153 	pmd_t *pmd;
154 	pte_t *pte;
155 
156 	relocated_restore_code = get_safe_page(GFP_ATOMIC);
157 	if (!relocated_restore_code)
158 		return -ENOMEM;
159 
160 	memcpy((void *)relocated_restore_code, core_restore_code, PAGE_SIZE);
161 
162 	/* Make the page containing the relocated code executable */
163 	pgd = (pgd_t *)__va(read_cr3_pa()) +
164 		pgd_index(relocated_restore_code);
165 	p4d = p4d_offset(pgd, relocated_restore_code);
166 	if (p4d_large(*p4d)) {
167 		set_p4d(p4d, __p4d(p4d_val(*p4d) & ~_PAGE_NX));
168 		goto out;
169 	}
170 	pud = pud_offset(p4d, relocated_restore_code);
171 	if (pud_large(*pud)) {
172 		set_pud(pud, __pud(pud_val(*pud) & ~_PAGE_NX));
173 		goto out;
174 	}
175 	pmd = pmd_offset(pud, relocated_restore_code);
176 	if (pmd_large(*pmd)) {
177 		set_pmd(pmd, __pmd(pmd_val(*pmd) & ~_PAGE_NX));
178 		goto out;
179 	}
180 	pte = pte_offset_kernel(pmd, relocated_restore_code);
181 	set_pte(pte, __pte(pte_val(*pte) & ~_PAGE_NX));
182 out:
183 	__flush_tlb_all();
184 	return 0;
185 }
186 
187 asmlinkage int swsusp_arch_resume(void)
188 {
189 	int error;
190 
191 	/* We have got enough memory and from now on we cannot recover */
192 	error = set_up_temporary_mappings();
193 	if (error)
194 		return error;
195 
196 	error = relocate_restore_code();
197 	if (error)
198 		return error;
199 
200 	restore_image();
201 	return 0;
202 }
203 
204 /*
205  *	pfn_is_nosave - check if given pfn is in the 'nosave' section
206  */
207 
208 int pfn_is_nosave(unsigned long pfn)
209 {
210 	unsigned long nosave_begin_pfn = __pa_symbol(&__nosave_begin) >> PAGE_SHIFT;
211 	unsigned long nosave_end_pfn = PAGE_ALIGN(__pa_symbol(&__nosave_end)) >> PAGE_SHIFT;
212 	return (pfn >= nosave_begin_pfn) && (pfn < nosave_end_pfn);
213 }
214 
215 #define MD5_DIGEST_SIZE 16
216 
217 struct restore_data_record {
218 	unsigned long jump_address;
219 	unsigned long jump_address_phys;
220 	unsigned long cr3;
221 	unsigned long magic;
222 	u8 e820_digest[MD5_DIGEST_SIZE];
223 };
224 
225 #define RESTORE_MAGIC	0x23456789ABCDEF01UL
226 
227 #if IS_BUILTIN(CONFIG_CRYPTO_MD5)
228 /**
229  * get_e820_md5 - calculate md5 according to given e820 table
230  *
231  * @table: the e820 table to be calculated
232  * @buf: the md5 result to be stored to
233  */
234 static int get_e820_md5(struct e820_table *table, void *buf)
235 {
236 	struct scatterlist sg;
237 	struct crypto_ahash *tfm;
238 	int size;
239 	int ret = 0;
240 
241 	tfm = crypto_alloc_ahash("md5", 0, CRYPTO_ALG_ASYNC);
242 	if (IS_ERR(tfm))
243 		return -ENOMEM;
244 
245 	{
246 		AHASH_REQUEST_ON_STACK(req, tfm);
247 		size = offsetof(struct e820_table, entries) + sizeof(struct e820_entry) * table->nr_entries;
248 		ahash_request_set_tfm(req, tfm);
249 		sg_init_one(&sg, (u8 *)table, size);
250 		ahash_request_set_callback(req, 0, NULL, NULL);
251 		ahash_request_set_crypt(req, &sg, buf, size);
252 
253 		if (crypto_ahash_digest(req))
254 			ret = -EINVAL;
255 		ahash_request_zero(req);
256 	}
257 	crypto_free_ahash(tfm);
258 
259 	return ret;
260 }
261 
262 static void hibernation_e820_save(void *buf)
263 {
264 	get_e820_md5(e820_table_firmware, buf);
265 }
266 
267 static bool hibernation_e820_mismatch(void *buf)
268 {
269 	int ret;
270 	u8 result[MD5_DIGEST_SIZE];
271 
272 	memset(result, 0, MD5_DIGEST_SIZE);
273 	/* If there is no digest in suspend kernel, let it go. */
274 	if (!memcmp(result, buf, MD5_DIGEST_SIZE))
275 		return false;
276 
277 	ret = get_e820_md5(e820_table_firmware, result);
278 	if (ret)
279 		return true;
280 
281 	return memcmp(result, buf, MD5_DIGEST_SIZE) ? true : false;
282 }
283 #else
284 static void hibernation_e820_save(void *buf)
285 {
286 }
287 
288 static bool hibernation_e820_mismatch(void *buf)
289 {
290 	/* If md5 is not builtin for restore kernel, let it go. */
291 	return false;
292 }
293 #endif
294 
295 /**
296  *	arch_hibernation_header_save - populate the architecture specific part
297  *		of a hibernation image header
298  *	@addr: address to save the data at
299  */
300 int arch_hibernation_header_save(void *addr, unsigned int max_size)
301 {
302 	struct restore_data_record *rdr = addr;
303 
304 	if (max_size < sizeof(struct restore_data_record))
305 		return -EOVERFLOW;
306 	rdr->jump_address = (unsigned long)restore_registers;
307 	rdr->jump_address_phys = __pa_symbol(restore_registers);
308 
309 	/*
310 	 * The restore code fixes up CR3 and CR4 in the following sequence:
311 	 *
312 	 * [in hibernation asm]
313 	 * 1. CR3 <= temporary page tables
314 	 * 2. CR4 <= mmu_cr4_features (from the kernel that restores us)
315 	 * 3. CR3 <= rdr->cr3
316 	 * 4. CR4 <= mmu_cr4_features (from us, i.e. the image kernel)
317 	 * [in restore_processor_state()]
318 	 * 5. CR4 <= saved CR4
319 	 * 6. CR3 <= saved CR3
320 	 *
321 	 * Our mmu_cr4_features has CR4.PCIDE=0, and toggling
322 	 * CR4.PCIDE while CR3's PCID bits are nonzero is illegal, so
323 	 * rdr->cr3 needs to point to valid page tables but must not
324 	 * have any of the PCID bits set.
325 	 */
326 	rdr->cr3 = restore_cr3 & ~CR3_PCID_MASK;
327 
328 	rdr->magic = RESTORE_MAGIC;
329 
330 	hibernation_e820_save(rdr->e820_digest);
331 
332 	return 0;
333 }
334 
335 /**
336  *	arch_hibernation_header_restore - read the architecture specific data
337  *		from the hibernation image header
338  *	@addr: address to read the data from
339  */
340 int arch_hibernation_header_restore(void *addr)
341 {
342 	struct restore_data_record *rdr = addr;
343 
344 	restore_jump_address = rdr->jump_address;
345 	jump_address_phys = rdr->jump_address_phys;
346 	restore_cr3 = rdr->cr3;
347 
348 	if (rdr->magic != RESTORE_MAGIC) {
349 		pr_crit("Unrecognized hibernate image header format!\n");
350 		return -EINVAL;
351 	}
352 
353 	if (hibernation_e820_mismatch(rdr->e820_digest)) {
354 		pr_crit("Hibernate inconsistent memory map detected!\n");
355 		return -ENODEV;
356 	}
357 
358 	return 0;
359 }
360