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Linux/arch/x86/power/hibernate_64.c

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  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 

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