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TOMOYO Linux Cross Reference
Linux/arch/x86/kernel/kexec-bzimage64.c

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  1 /*
  2  * Kexec bzImage loader
  3  *
  4  * Copyright (C) 2014 Red Hat Inc.
  5  * Authors:
  6  *      Vivek Goyal <vgoyal@redhat.com>
  7  *
  8  * This source code is licensed under the GNU General Public License,
  9  * Version 2.  See the file COPYING for more details.
 10  */
 11 
 12 #define pr_fmt(fmt)     "kexec-bzImage64: " fmt
 13 
 14 #include <linux/string.h>
 15 #include <linux/printk.h>
 16 #include <linux/errno.h>
 17 #include <linux/slab.h>
 18 #include <linux/kexec.h>
 19 #include <linux/kernel.h>
 20 #include <linux/mm.h>
 21 #include <linux/efi.h>
 22 #include <linux/verification.h>
 23 
 24 #include <asm/bootparam.h>
 25 #include <asm/setup.h>
 26 #include <asm/crash.h>
 27 #include <asm/efi.h>
 28 #include <asm/e820/api.h>
 29 #include <asm/kexec-bzimage64.h>
 30 
 31 #define MAX_ELFCOREHDR_STR_LEN  30      /* elfcorehdr=0x<64bit-value> */
 32 
 33 /*
 34  * Defines lowest physical address for various segments. Not sure where
 35  * exactly these limits came from. Current bzimage64 loader in kexec-tools
 36  * uses these so I am retaining it. It can be changed over time as we gain
 37  * more insight.
 38  */
 39 #define MIN_PURGATORY_ADDR      0x3000
 40 #define MIN_BOOTPARAM_ADDR      0x3000
 41 #define MIN_KERNEL_LOAD_ADDR    0x100000
 42 #define MIN_INITRD_LOAD_ADDR    0x1000000
 43 
 44 /*
 45  * This is a place holder for all boot loader specific data structure which
 46  * gets allocated in one call but gets freed much later during cleanup
 47  * time. Right now there is only one field but it can grow as need be.
 48  */
 49 struct bzimage64_data {
 50         /*
 51          * Temporary buffer to hold bootparams buffer. This should be
 52          * freed once the bootparam segment has been loaded.
 53          */
 54         void *bootparams_buf;
 55 };
 56 
 57 static int setup_initrd(struct boot_params *params,
 58                 unsigned long initrd_load_addr, unsigned long initrd_len)
 59 {
 60         params->hdr.ramdisk_image = initrd_load_addr & 0xffffffffUL;
 61         params->hdr.ramdisk_size = initrd_len & 0xffffffffUL;
 62 
 63         params->ext_ramdisk_image = initrd_load_addr >> 32;
 64         params->ext_ramdisk_size = initrd_len >> 32;
 65 
 66         return 0;
 67 }
 68 
 69 static int setup_cmdline(struct kimage *image, struct boot_params *params,
 70                          unsigned long bootparams_load_addr,
 71                          unsigned long cmdline_offset, char *cmdline,
 72                          unsigned long cmdline_len)
 73 {
 74         char *cmdline_ptr = ((char *)params) + cmdline_offset;
 75         unsigned long cmdline_ptr_phys, len = 0;
 76         uint32_t cmdline_low_32, cmdline_ext_32;
 77 
 78         if (image->type == KEXEC_TYPE_CRASH) {
 79                 len = sprintf(cmdline_ptr,
 80                         "elfcorehdr=0x%lx ", image->arch.elf_load_addr);
 81         }
 82         memcpy(cmdline_ptr + len, cmdline, cmdline_len);
 83         cmdline_len += len;
 84 
 85         cmdline_ptr[cmdline_len - 1] = '\0';
 86 
 87         pr_debug("Final command line is: %s\n", cmdline_ptr);
 88         cmdline_ptr_phys = bootparams_load_addr + cmdline_offset;
 89         cmdline_low_32 = cmdline_ptr_phys & 0xffffffffUL;
 90         cmdline_ext_32 = cmdline_ptr_phys >> 32;
 91 
 92         params->hdr.cmd_line_ptr = cmdline_low_32;
 93         if (cmdline_ext_32)
 94                 params->ext_cmd_line_ptr = cmdline_ext_32;
 95 
 96         return 0;
 97 }
 98 
 99 static int setup_e820_entries(struct boot_params *params)
100 {
101         unsigned int nr_e820_entries;
102 
103         nr_e820_entries = e820_table_kexec->nr_entries;
104 
105         /* TODO: Pass entries more than E820_MAX_ENTRIES_ZEROPAGE in bootparams setup data */
106         if (nr_e820_entries > E820_MAX_ENTRIES_ZEROPAGE)
107                 nr_e820_entries = E820_MAX_ENTRIES_ZEROPAGE;
108 
109         params->e820_entries = nr_e820_entries;
110         memcpy(&params->e820_table, &e820_table_kexec->entries, nr_e820_entries*sizeof(struct e820_entry));
111 
112         return 0;
113 }
114 
115 #ifdef CONFIG_EFI
116 static int setup_efi_info_memmap(struct boot_params *params,
117                                   unsigned long params_load_addr,
118                                   unsigned int efi_map_offset,
119                                   unsigned int efi_map_sz)
120 {
121         void *efi_map = (void *)params + efi_map_offset;
122         unsigned long efi_map_phys_addr = params_load_addr + efi_map_offset;
123         struct efi_info *ei = &params->efi_info;
124 
125         if (!efi_map_sz)
126                 return 0;
127 
128         efi_runtime_map_copy(efi_map, efi_map_sz);
129 
130         ei->efi_memmap = efi_map_phys_addr & 0xffffffff;
131         ei->efi_memmap_hi = efi_map_phys_addr >> 32;
132         ei->efi_memmap_size = efi_map_sz;
133 
134         return 0;
135 }
136 
137 static int
138 prepare_add_efi_setup_data(struct boot_params *params,
139                        unsigned long params_load_addr,
140                        unsigned int efi_setup_data_offset)
141 {
142         unsigned long setup_data_phys;
143         struct setup_data *sd = (void *)params + efi_setup_data_offset;
144         struct efi_setup_data *esd = (void *)sd + sizeof(struct setup_data);
145 
146         esd->fw_vendor = efi.fw_vendor;
147         esd->runtime = efi.runtime;
148         esd->tables = efi.config_table;
149         esd->smbios = efi.smbios;
150 
151         sd->type = SETUP_EFI;
152         sd->len = sizeof(struct efi_setup_data);
153 
154         /* Add setup data */
155         setup_data_phys = params_load_addr + efi_setup_data_offset;
156         sd->next = params->hdr.setup_data;
157         params->hdr.setup_data = setup_data_phys;
158 
159         return 0;
160 }
161 
162 static int
163 setup_efi_state(struct boot_params *params, unsigned long params_load_addr,
164                 unsigned int efi_map_offset, unsigned int efi_map_sz,
165                 unsigned int efi_setup_data_offset)
166 {
167         struct efi_info *current_ei = &boot_params.efi_info;
168         struct efi_info *ei = &params->efi_info;
169 
170         if (!current_ei->efi_memmap_size)
171                 return 0;
172 
173         /*
174          * If 1:1 mapping is not enabled, second kernel can not setup EFI
175          * and use EFI run time services. User space will have to pass
176          * acpi_rsdp=<addr> on kernel command line to make second kernel boot
177          * without efi.
178          */
179         if (efi_enabled(EFI_OLD_MEMMAP))
180                 return 0;
181 
182         ei->efi_loader_signature = current_ei->efi_loader_signature;
183         ei->efi_systab = current_ei->efi_systab;
184         ei->efi_systab_hi = current_ei->efi_systab_hi;
185 
186         ei->efi_memdesc_version = current_ei->efi_memdesc_version;
187         ei->efi_memdesc_size = efi_get_runtime_map_desc_size();
188 
189         setup_efi_info_memmap(params, params_load_addr, efi_map_offset,
190                               efi_map_sz);
191         prepare_add_efi_setup_data(params, params_load_addr,
192                                    efi_setup_data_offset);
193         return 0;
194 }
195 #endif /* CONFIG_EFI */
196 
197 static int
198 setup_boot_parameters(struct kimage *image, struct boot_params *params,
199                       unsigned long params_load_addr,
200                       unsigned int efi_map_offset, unsigned int efi_map_sz,
201                       unsigned int efi_setup_data_offset)
202 {
203         unsigned int nr_e820_entries;
204         unsigned long long mem_k, start, end;
205         int i, ret = 0;
206 
207         /* Get subarch from existing bootparams */
208         params->hdr.hardware_subarch = boot_params.hdr.hardware_subarch;
209 
210         /* Copying screen_info will do? */
211         memcpy(&params->screen_info, &boot_params.screen_info,
212                                 sizeof(struct screen_info));
213 
214         /* Fill in memsize later */
215         params->screen_info.ext_mem_k = 0;
216         params->alt_mem_k = 0;
217 
218         /* Default APM info */
219         memset(&params->apm_bios_info, 0, sizeof(params->apm_bios_info));
220 
221         /* Default drive info */
222         memset(&params->hd0_info, 0, sizeof(params->hd0_info));
223         memset(&params->hd1_info, 0, sizeof(params->hd1_info));
224 
225         if (image->type == KEXEC_TYPE_CRASH) {
226                 ret = crash_setup_memmap_entries(image, params);
227                 if (ret)
228                         return ret;
229         } else
230                 setup_e820_entries(params);
231 
232         nr_e820_entries = params->e820_entries;
233 
234         for (i = 0; i < nr_e820_entries; i++) {
235                 if (params->e820_table[i].type != E820_TYPE_RAM)
236                         continue;
237                 start = params->e820_table[i].addr;
238                 end = params->e820_table[i].addr + params->e820_table[i].size - 1;
239 
240                 if ((start <= 0x100000) && end > 0x100000) {
241                         mem_k = (end >> 10) - (0x100000 >> 10);
242                         params->screen_info.ext_mem_k = mem_k;
243                         params->alt_mem_k = mem_k;
244                         if (mem_k > 0xfc00)
245                                 params->screen_info.ext_mem_k = 0xfc00; /* 64M*/
246                         if (mem_k > 0xffffffff)
247                                 params->alt_mem_k = 0xffffffff;
248                 }
249         }
250 
251 #ifdef CONFIG_EFI
252         /* Setup EFI state */
253         setup_efi_state(params, params_load_addr, efi_map_offset, efi_map_sz,
254                         efi_setup_data_offset);
255 #endif
256 
257         /* Setup EDD info */
258         memcpy(params->eddbuf, boot_params.eddbuf,
259                                 EDDMAXNR * sizeof(struct edd_info));
260         params->eddbuf_entries = boot_params.eddbuf_entries;
261 
262         memcpy(params->edd_mbr_sig_buffer, boot_params.edd_mbr_sig_buffer,
263                EDD_MBR_SIG_MAX * sizeof(unsigned int));
264 
265         return ret;
266 }
267 
268 static int bzImage64_probe(const char *buf, unsigned long len)
269 {
270         int ret = -ENOEXEC;
271         struct setup_header *header;
272 
273         /* kernel should be at least two sectors long */
274         if (len < 2 * 512) {
275                 pr_err("File is too short to be a bzImage\n");
276                 return ret;
277         }
278 
279         header = (struct setup_header *)(buf + offsetof(struct boot_params, hdr));
280         if (memcmp((char *)&header->header, "HdrS", 4) != 0) {
281                 pr_err("Not a bzImage\n");
282                 return ret;
283         }
284 
285         if (header->boot_flag != 0xAA55) {
286                 pr_err("No x86 boot sector present\n");
287                 return ret;
288         }
289 
290         if (header->version < 0x020C) {
291                 pr_err("Must be at least protocol version 2.12\n");
292                 return ret;
293         }
294 
295         if (!(header->loadflags & LOADED_HIGH)) {
296                 pr_err("zImage not a bzImage\n");
297                 return ret;
298         }
299 
300         if (!(header->xloadflags & XLF_KERNEL_64)) {
301                 pr_err("Not a bzImage64. XLF_KERNEL_64 is not set.\n");
302                 return ret;
303         }
304 
305         if (!(header->xloadflags & XLF_CAN_BE_LOADED_ABOVE_4G)) {
306                 pr_err("XLF_CAN_BE_LOADED_ABOVE_4G is not set.\n");
307                 return ret;
308         }
309 
310         /*
311          * Can't handle 32bit EFI as it does not allow loading kernel
312          * above 4G. This should be handled by 32bit bzImage loader
313          */
314         if (efi_enabled(EFI_RUNTIME_SERVICES) && !efi_enabled(EFI_64BIT)) {
315                 pr_debug("EFI is 32 bit. Can't load kernel above 4G.\n");
316                 return ret;
317         }
318 
319         /* I've got a bzImage */
320         pr_debug("It's a relocatable bzImage64\n");
321         ret = 0;
322 
323         return ret;
324 }
325 
326 static void *bzImage64_load(struct kimage *image, char *kernel,
327                             unsigned long kernel_len, char *initrd,
328                             unsigned long initrd_len, char *cmdline,
329                             unsigned long cmdline_len)
330 {
331 
332         struct setup_header *header;
333         int setup_sects, kern16_size, ret = 0;
334         unsigned long setup_header_size, params_cmdline_sz;
335         struct boot_params *params;
336         unsigned long bootparam_load_addr, kernel_load_addr, initrd_load_addr;
337         unsigned long purgatory_load_addr;
338         struct bzimage64_data *ldata;
339         struct kexec_entry64_regs regs64;
340         void *stack;
341         unsigned int setup_hdr_offset = offsetof(struct boot_params, hdr);
342         unsigned int efi_map_offset, efi_map_sz, efi_setup_data_offset;
343         struct kexec_buf kbuf = { .image = image, .buf_max = ULONG_MAX,
344                                   .top_down = true };
345 
346         header = (struct setup_header *)(kernel + setup_hdr_offset);
347         setup_sects = header->setup_sects;
348         if (setup_sects == 0)
349                 setup_sects = 4;
350 
351         kern16_size = (setup_sects + 1) * 512;
352         if (kernel_len < kern16_size) {
353                 pr_err("bzImage truncated\n");
354                 return ERR_PTR(-ENOEXEC);
355         }
356 
357         if (cmdline_len > header->cmdline_size) {
358                 pr_err("Kernel command line too long\n");
359                 return ERR_PTR(-EINVAL);
360         }
361 
362         /*
363          * In case of crash dump, we will append elfcorehdr=<addr> to
364          * command line. Make sure it does not overflow
365          */
366         if (cmdline_len + MAX_ELFCOREHDR_STR_LEN > header->cmdline_size) {
367                 pr_debug("Appending elfcorehdr=<addr> to command line exceeds maximum allowed length\n");
368                 return ERR_PTR(-EINVAL);
369         }
370 
371         /* Allocate and load backup region */
372         if (image->type == KEXEC_TYPE_CRASH) {
373                 ret = crash_load_segments(image);
374                 if (ret)
375                         return ERR_PTR(ret);
376         }
377 
378         /*
379          * Load purgatory. For 64bit entry point, purgatory  code can be
380          * anywhere.
381          */
382         ret = kexec_load_purgatory(image, MIN_PURGATORY_ADDR, ULONG_MAX, 1,
383                                    &purgatory_load_addr);
384         if (ret) {
385                 pr_err("Loading purgatory failed\n");
386                 return ERR_PTR(ret);
387         }
388 
389         pr_debug("Loaded purgatory at 0x%lx\n", purgatory_load_addr);
390 
391 
392         /*
393          * Load Bootparams and cmdline and space for efi stuff.
394          *
395          * Allocate memory together for multiple data structures so
396          * that they all can go in single area/segment and we don't
397          * have to create separate segment for each. Keeps things
398          * little bit simple
399          */
400         efi_map_sz = efi_get_runtime_map_size();
401         params_cmdline_sz = sizeof(struct boot_params) + cmdline_len +
402                                 MAX_ELFCOREHDR_STR_LEN;
403         params_cmdline_sz = ALIGN(params_cmdline_sz, 16);
404         kbuf.bufsz = params_cmdline_sz + ALIGN(efi_map_sz, 16) +
405                                 sizeof(struct setup_data) +
406                                 sizeof(struct efi_setup_data);
407 
408         params = kzalloc(kbuf.bufsz, GFP_KERNEL);
409         if (!params)
410                 return ERR_PTR(-ENOMEM);
411         efi_map_offset = params_cmdline_sz;
412         efi_setup_data_offset = efi_map_offset + ALIGN(efi_map_sz, 16);
413 
414         /* Copy setup header onto bootparams. Documentation/x86/boot.txt */
415         setup_header_size = 0x0202 + kernel[0x0201] - setup_hdr_offset;
416 
417         /* Is there a limit on setup header size? */
418         memcpy(&params->hdr, (kernel + setup_hdr_offset), setup_header_size);
419 
420         kbuf.buffer = params;
421         kbuf.memsz = kbuf.bufsz;
422         kbuf.buf_align = 16;
423         kbuf.buf_min = MIN_BOOTPARAM_ADDR;
424         ret = kexec_add_buffer(&kbuf);
425         if (ret)
426                 goto out_free_params;
427         bootparam_load_addr = kbuf.mem;
428         pr_debug("Loaded boot_param, command line and misc at 0x%lx bufsz=0x%lx memsz=0x%lx\n",
429                  bootparam_load_addr, kbuf.bufsz, kbuf.bufsz);
430 
431         /* Load kernel */
432         kbuf.buffer = kernel + kern16_size;
433         kbuf.bufsz =  kernel_len - kern16_size;
434         kbuf.memsz = PAGE_ALIGN(header->init_size);
435         kbuf.buf_align = header->kernel_alignment;
436         kbuf.buf_min = MIN_KERNEL_LOAD_ADDR;
437         ret = kexec_add_buffer(&kbuf);
438         if (ret)
439                 goto out_free_params;
440         kernel_load_addr = kbuf.mem;
441 
442         pr_debug("Loaded 64bit kernel at 0x%lx bufsz=0x%lx memsz=0x%lx\n",
443                  kernel_load_addr, kbuf.bufsz, kbuf.memsz);
444 
445         /* Load initrd high */
446         if (initrd) {
447                 kbuf.buffer = initrd;
448                 kbuf.bufsz = kbuf.memsz = initrd_len;
449                 kbuf.buf_align = PAGE_SIZE;
450                 kbuf.buf_min = MIN_INITRD_LOAD_ADDR;
451                 ret = kexec_add_buffer(&kbuf);
452                 if (ret)
453                         goto out_free_params;
454                 initrd_load_addr = kbuf.mem;
455 
456                 pr_debug("Loaded initrd at 0x%lx bufsz=0x%lx memsz=0x%lx\n",
457                                 initrd_load_addr, initrd_len, initrd_len);
458 
459                 setup_initrd(params, initrd_load_addr, initrd_len);
460         }
461 
462         setup_cmdline(image, params, bootparam_load_addr,
463                       sizeof(struct boot_params), cmdline, cmdline_len);
464 
465         /* bootloader info. Do we need a separate ID for kexec kernel loader? */
466         params->hdr.type_of_loader = 0x0D << 4;
467         params->hdr.loadflags = 0;
468 
469         /* Setup purgatory regs for entry */
470         ret = kexec_purgatory_get_set_symbol(image, "entry64_regs", &regs64,
471                                              sizeof(regs64), 1);
472         if (ret)
473                 goto out_free_params;
474 
475         regs64.rbx = 0; /* Bootstrap Processor */
476         regs64.rsi = bootparam_load_addr;
477         regs64.rip = kernel_load_addr + 0x200;
478         stack = kexec_purgatory_get_symbol_addr(image, "stack_end");
479         if (IS_ERR(stack)) {
480                 pr_err("Could not find address of symbol stack_end\n");
481                 ret = -EINVAL;
482                 goto out_free_params;
483         }
484 
485         regs64.rsp = (unsigned long)stack;
486         ret = kexec_purgatory_get_set_symbol(image, "entry64_regs", &regs64,
487                                              sizeof(regs64), 0);
488         if (ret)
489                 goto out_free_params;
490 
491         ret = setup_boot_parameters(image, params, bootparam_load_addr,
492                                     efi_map_offset, efi_map_sz,
493                                     efi_setup_data_offset);
494         if (ret)
495                 goto out_free_params;
496 
497         /* Allocate loader specific data */
498         ldata = kzalloc(sizeof(struct bzimage64_data), GFP_KERNEL);
499         if (!ldata) {
500                 ret = -ENOMEM;
501                 goto out_free_params;
502         }
503 
504         /*
505          * Store pointer to params so that it could be freed after loading
506          * params segment has been loaded and contents have been copied
507          * somewhere else.
508          */
509         ldata->bootparams_buf = params;
510         return ldata;
511 
512 out_free_params:
513         kfree(params);
514         return ERR_PTR(ret);
515 }
516 
517 /* This cleanup function is called after various segments have been loaded */
518 static int bzImage64_cleanup(void *loader_data)
519 {
520         struct bzimage64_data *ldata = loader_data;
521 
522         if (!ldata)
523                 return 0;
524 
525         kfree(ldata->bootparams_buf);
526         ldata->bootparams_buf = NULL;
527 
528         return 0;
529 }
530 
531 #ifdef CONFIG_KEXEC_BZIMAGE_VERIFY_SIG
532 static int bzImage64_verify_sig(const char *kernel, unsigned long kernel_len)
533 {
534         return verify_pefile_signature(kernel, kernel_len,
535                                        NULL,
536                                        VERIFYING_KEXEC_PE_SIGNATURE);
537 }
538 #endif
539 
540 struct kexec_file_ops kexec_bzImage64_ops = {
541         .probe = bzImage64_probe,
542         .load = bzImage64_load,
543         .cleanup = bzImage64_cleanup,
544 #ifdef CONFIG_KEXEC_BZIMAGE_VERIFY_SIG
545         .verify_sig = bzImage64_verify_sig,
546 #endif
547 };
548 

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