xref: /openbmc/linux/arch/x86/power/hibernate_64.c (revision f7c35abe)
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/init.h>
20 #include <asm/proto.h>
21 #include <asm/page.h>
22 #include <asm/pgtable.h>
23 #include <asm/mtrr.h>
24 #include <asm/sections.h>
25 #include <asm/suspend.h>
26 #include <asm/tlbflush.h>
27 
28 /* Defined in hibernate_asm_64.S */
29 extern asmlinkage __visible int restore_image(void);
30 
31 /*
32  * Address to jump to in the last phase of restore in order to get to the image
33  * kernel's text (this value is passed in the image header).
34  */
35 unsigned long restore_jump_address __visible;
36 unsigned long jump_address_phys;
37 
38 /*
39  * Value of the cr3 register from before the hibernation (this value is passed
40  * in the image header).
41  */
42 unsigned long restore_cr3 __visible;
43 
44 unsigned long temp_level4_pgt __visible;
45 
46 unsigned long relocated_restore_code __visible;
47 
48 static int set_up_temporary_text_mapping(pgd_t *pgd)
49 {
50 	pmd_t *pmd;
51 	pud_t *pud;
52 
53 	/*
54 	 * The new mapping only has to cover the page containing the image
55 	 * kernel's entry point (jump_address_phys), because the switch over to
56 	 * it is carried out by relocated code running from a page allocated
57 	 * specifically for this purpose and covered by the identity mapping, so
58 	 * the temporary kernel text mapping is only needed for the final jump.
59 	 * Moreover, in that mapping the virtual address of the image kernel's
60 	 * entry point must be the same as its virtual address in the image
61 	 * kernel (restore_jump_address), so the image kernel's
62 	 * restore_registers() code doesn't find itself in a different area of
63 	 * the virtual address space after switching over to the original page
64 	 * tables used by the image kernel.
65 	 */
66 	pud = (pud_t *)get_safe_page(GFP_ATOMIC);
67 	if (!pud)
68 		return -ENOMEM;
69 
70 	pmd = (pmd_t *)get_safe_page(GFP_ATOMIC);
71 	if (!pmd)
72 		return -ENOMEM;
73 
74 	set_pmd(pmd + pmd_index(restore_jump_address),
75 		__pmd((jump_address_phys & PMD_MASK) | __PAGE_KERNEL_LARGE_EXEC));
76 	set_pud(pud + pud_index(restore_jump_address),
77 		__pud(__pa(pmd) | _KERNPG_TABLE));
78 	set_pgd(pgd + pgd_index(restore_jump_address),
79 		__pgd(__pa(pud) | _KERNPG_TABLE));
80 
81 	return 0;
82 }
83 
84 static void *alloc_pgt_page(void *context)
85 {
86 	return (void *)get_safe_page(GFP_ATOMIC);
87 }
88 
89 static int set_up_temporary_mappings(void)
90 {
91 	struct x86_mapping_info info = {
92 		.alloc_pgt_page	= alloc_pgt_page,
93 		.pmd_flag	= __PAGE_KERNEL_LARGE_EXEC,
94 		.offset		= __PAGE_OFFSET,
95 	};
96 	unsigned long mstart, mend;
97 	pgd_t *pgd;
98 	int result;
99 	int i;
100 
101 	pgd = (pgd_t *)get_safe_page(GFP_ATOMIC);
102 	if (!pgd)
103 		return -ENOMEM;
104 
105 	/* Prepare a temporary mapping for the kernel text */
106 	result = set_up_temporary_text_mapping(pgd);
107 	if (result)
108 		return result;
109 
110 	/* Set up the direct mapping from scratch */
111 	for (i = 0; i < nr_pfn_mapped; i++) {
112 		mstart = pfn_mapped[i].start << PAGE_SHIFT;
113 		mend   = pfn_mapped[i].end << PAGE_SHIFT;
114 
115 		result = kernel_ident_mapping_init(&info, pgd, mstart, mend);
116 		if (result)
117 			return result;
118 	}
119 
120 	temp_level4_pgt = __pa(pgd);
121 	return 0;
122 }
123 
124 static int relocate_restore_code(void)
125 {
126 	pgd_t *pgd;
127 	pud_t *pud;
128 
129 	relocated_restore_code = get_safe_page(GFP_ATOMIC);
130 	if (!relocated_restore_code)
131 		return -ENOMEM;
132 
133 	memcpy((void *)relocated_restore_code, &core_restore_code, PAGE_SIZE);
134 
135 	/* Make the page containing the relocated code executable */
136 	pgd = (pgd_t *)__va(read_cr3()) + pgd_index(relocated_restore_code);
137 	pud = pud_offset(pgd, relocated_restore_code);
138 	if (pud_large(*pud)) {
139 		set_pud(pud, __pud(pud_val(*pud) & ~_PAGE_NX));
140 	} else {
141 		pmd_t *pmd = pmd_offset(pud, relocated_restore_code);
142 
143 		if (pmd_large(*pmd)) {
144 			set_pmd(pmd, __pmd(pmd_val(*pmd) & ~_PAGE_NX));
145 		} else {
146 			pte_t *pte = pte_offset_kernel(pmd, relocated_restore_code);
147 
148 			set_pte(pte, __pte(pte_val(*pte) & ~_PAGE_NX));
149 		}
150 	}
151 	__flush_tlb_all();
152 
153 	return 0;
154 }
155 
156 int swsusp_arch_resume(void)
157 {
158 	int error;
159 
160 	/* We have got enough memory and from now on we cannot recover */
161 	error = set_up_temporary_mappings();
162 	if (error)
163 		return error;
164 
165 	error = relocate_restore_code();
166 	if (error)
167 		return error;
168 
169 	restore_image();
170 	return 0;
171 }
172 
173 /*
174  *	pfn_is_nosave - check if given pfn is in the 'nosave' section
175  */
176 
177 int pfn_is_nosave(unsigned long pfn)
178 {
179 	unsigned long nosave_begin_pfn = __pa_symbol(&__nosave_begin) >> PAGE_SHIFT;
180 	unsigned long nosave_end_pfn = PAGE_ALIGN(__pa_symbol(&__nosave_end)) >> PAGE_SHIFT;
181 	return (pfn >= nosave_begin_pfn) && (pfn < nosave_end_pfn);
182 }
183 
184 #define MD5_DIGEST_SIZE 16
185 
186 struct restore_data_record {
187 	unsigned long jump_address;
188 	unsigned long jump_address_phys;
189 	unsigned long cr3;
190 	unsigned long magic;
191 	u8 e820_digest[MD5_DIGEST_SIZE];
192 };
193 
194 #define RESTORE_MAGIC	0x23456789ABCDEF01UL
195 
196 #if IS_BUILTIN(CONFIG_CRYPTO_MD5)
197 /**
198  * get_e820_md5 - calculate md5 according to given e820 map
199  *
200  * @map: the e820 map to be calculated
201  * @buf: the md5 result to be stored to
202  */
203 static int get_e820_md5(struct e820map *map, void *buf)
204 {
205 	struct scatterlist sg;
206 	struct crypto_ahash *tfm;
207 	int size;
208 	int ret = 0;
209 
210 	tfm = crypto_alloc_ahash("md5", 0, CRYPTO_ALG_ASYNC);
211 	if (IS_ERR(tfm))
212 		return -ENOMEM;
213 
214 	{
215 		AHASH_REQUEST_ON_STACK(req, tfm);
216 		size = offsetof(struct e820map, map)
217 			+ sizeof(struct e820entry) * map->nr_map;
218 		ahash_request_set_tfm(req, tfm);
219 		sg_init_one(&sg, (u8 *)map, size);
220 		ahash_request_set_callback(req, 0, NULL, NULL);
221 		ahash_request_set_crypt(req, &sg, buf, size);
222 
223 		if (crypto_ahash_digest(req))
224 			ret = -EINVAL;
225 		ahash_request_zero(req);
226 	}
227 	crypto_free_ahash(tfm);
228 
229 	return ret;
230 }
231 
232 static void hibernation_e820_save(void *buf)
233 {
234 	get_e820_md5(e820_saved, buf);
235 }
236 
237 static bool hibernation_e820_mismatch(void *buf)
238 {
239 	int ret;
240 	u8 result[MD5_DIGEST_SIZE];
241 
242 	memset(result, 0, MD5_DIGEST_SIZE);
243 	/* If there is no digest in suspend kernel, let it go. */
244 	if (!memcmp(result, buf, MD5_DIGEST_SIZE))
245 		return false;
246 
247 	ret = get_e820_md5(e820_saved, result);
248 	if (ret)
249 		return true;
250 
251 	return memcmp(result, buf, MD5_DIGEST_SIZE) ? true : false;
252 }
253 #else
254 static void hibernation_e820_save(void *buf)
255 {
256 }
257 
258 static bool hibernation_e820_mismatch(void *buf)
259 {
260 	/* If md5 is not builtin for restore kernel, let it go. */
261 	return false;
262 }
263 #endif
264 
265 /**
266  *	arch_hibernation_header_save - populate the architecture specific part
267  *		of a hibernation image header
268  *	@addr: address to save the data at
269  */
270 int arch_hibernation_header_save(void *addr, unsigned int max_size)
271 {
272 	struct restore_data_record *rdr = addr;
273 
274 	if (max_size < sizeof(struct restore_data_record))
275 		return -EOVERFLOW;
276 	rdr->jump_address = (unsigned long)&restore_registers;
277 	rdr->jump_address_phys = __pa_symbol(&restore_registers);
278 	rdr->cr3 = restore_cr3;
279 	rdr->magic = RESTORE_MAGIC;
280 
281 	hibernation_e820_save(rdr->e820_digest);
282 
283 	return 0;
284 }
285 
286 /**
287  *	arch_hibernation_header_restore - read the architecture specific data
288  *		from the hibernation image header
289  *	@addr: address to read the data from
290  */
291 int arch_hibernation_header_restore(void *addr)
292 {
293 	struct restore_data_record *rdr = addr;
294 
295 	restore_jump_address = rdr->jump_address;
296 	jump_address_phys = rdr->jump_address_phys;
297 	restore_cr3 = rdr->cr3;
298 
299 	if (rdr->magic != RESTORE_MAGIC) {
300 		pr_crit("Unrecognized hibernate image header format!\n");
301 		return -EINVAL;
302 	}
303 
304 	if (hibernation_e820_mismatch(rdr->e820_digest)) {
305 		pr_crit("Hibernate inconsistent memory map detected!\n");
306 		return -ENODEV;
307 	}
308 
309 	return 0;
310 }
311