1 /*
2 * Common EFI (Extensible Firmware Interface) support functions
3 * Based on Extensible Firmware Interface Specification version 1.0
4 *
5 * Copyright (C) 1999 VA Linux Systems
6 * Copyright (C) 1999 Walt Drummond <drummond@valinux.com>
7 * Copyright (C) 1999-2002 Hewlett-Packard Co.
8 * David Mosberger-Tang <davidm@hpl.hp.com>
9 * Stephane Eranian <eranian@hpl.hp.com>
10 * Copyright (C) 2005-2008 Intel Co.
11 * Fenghua Yu <fenghua.yu@intel.com>
12 * Bibo Mao <bibo.mao@intel.com>
13 * Chandramouli Narayanan <mouli@linux.intel.com>
14 * Huang Ying <ying.huang@intel.com>
15 * Copyright (C) 2013 SuSE Labs
16 * Borislav Petkov <bp@suse.de> - runtime services VA mapping
17 *
18 * Copied from efi_32.c to eliminate the duplicated code between EFI
19 * 32/64 support code. --ying 2007-10-26
20 *
21 * All EFI Runtime Services are not implemented yet as EFI only
22 * supports physical mode addressing on SoftSDV. This is to be fixed
23 * in a future version. --drummond 1999-07-20
24 *
25 * Implemented EFI runtime services and virtual mode calls. --davidm
26 *
27 * Goutham Rao: <goutham.rao@intel.com>
28 * Skip non-WB memory and ignore empty memory ranges.
29 */
30
31 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
32
33 #include <linux/kernel.h>
34 #include <linux/init.h>
35 #include <linux/efi.h>
36 #include <linux/efi-bgrt.h>
37 #include <linux/export.h>
38 #include <linux/bootmem.h>
39 #include <linux/slab.h>
40 #include <linux/memblock.h>
41 #include <linux/spinlock.h>
42 #include <linux/uaccess.h>
43 #include <linux/time.h>
44 #include <linux/io.h>
45 #include <linux/reboot.h>
46 #include <linux/bcd.h>
47
48 #include <asm/setup.h>
49 #include <asm/efi.h>
50 #include <asm/time.h>
51 #include <asm/cacheflush.h>
52 #include <asm/tlbflush.h>
53 #include <asm/x86_init.h>
54 #include <asm/rtc.h>
55 #include <asm/uv/uv.h>
56
57 #define EFI_DEBUG
58
59 struct efi_memory_map memmap;
60
61 static struct efi efi_phys __initdata;
62 static efi_system_table_t efi_systab __initdata;
63
64 static efi_config_table_type_t arch_tables[] __initdata = {
65 #ifdef CONFIG_X86_UV
66 {UV_SYSTEM_TABLE_GUID, "UVsystab", &efi.uv_systab},
67 #endif
68 {NULL_GUID, NULL, NULL},
69 };
70
71 u64 efi_setup; /* efi setup_data physical address */
72
73 static int add_efi_memmap __initdata;
setup_add_efi_memmap(char * arg)74 static int __init setup_add_efi_memmap(char *arg)
75 {
76 add_efi_memmap = 1;
77 return 0;
78 }
79 early_param("add_efi_memmap", setup_add_efi_memmap);
80
phys_efi_set_virtual_address_map(unsigned long memory_map_size,unsigned long descriptor_size,u32 descriptor_version,efi_memory_desc_t * virtual_map)81 static efi_status_t __init phys_efi_set_virtual_address_map(
82 unsigned long memory_map_size,
83 unsigned long descriptor_size,
84 u32 descriptor_version,
85 efi_memory_desc_t *virtual_map)
86 {
87 efi_status_t status;
88 unsigned long flags;
89 pgd_t *save_pgd;
90
91 save_pgd = efi_call_phys_prolog();
92
93 /* Disable interrupts around EFI calls: */
94 local_irq_save(flags);
95 status = efi_call_phys(efi_phys.set_virtual_address_map,
96 memory_map_size, descriptor_size,
97 descriptor_version, virtual_map);
98 local_irq_restore(flags);
99
100 efi_call_phys_epilog(save_pgd);
101
102 return status;
103 }
104
efi_get_time(struct timespec * now)105 void efi_get_time(struct timespec *now)
106 {
107 efi_status_t status;
108 efi_time_t eft;
109 efi_time_cap_t cap;
110
111 status = efi.get_time(&eft, &cap);
112 if (status != EFI_SUCCESS)
113 pr_err("Oops: efitime: can't read time!\n");
114
115 now->tv_sec = mktime(eft.year, eft.month, eft.day, eft.hour,
116 eft.minute, eft.second);
117 now->tv_nsec = 0;
118 }
119
120 /*
121 * Tell the kernel about the EFI memory map. This might include
122 * more than the max 128 entries that can fit in the e820 legacy
123 * (zeropage) memory map.
124 */
125
do_add_efi_memmap(void)126 static void __init do_add_efi_memmap(void)
127 {
128 void *p;
129
130 for (p = memmap.map; p < memmap.map_end; p += memmap.desc_size) {
131 efi_memory_desc_t *md = p;
132 unsigned long long start = md->phys_addr;
133 unsigned long long size = md->num_pages << EFI_PAGE_SHIFT;
134 int e820_type;
135
136 switch (md->type) {
137 case EFI_LOADER_CODE:
138 case EFI_LOADER_DATA:
139 case EFI_BOOT_SERVICES_CODE:
140 case EFI_BOOT_SERVICES_DATA:
141 case EFI_CONVENTIONAL_MEMORY:
142 if (md->attribute & EFI_MEMORY_WB)
143 e820_type = E820_RAM;
144 else
145 e820_type = E820_RESERVED;
146 break;
147 case EFI_ACPI_RECLAIM_MEMORY:
148 e820_type = E820_ACPI;
149 break;
150 case EFI_ACPI_MEMORY_NVS:
151 e820_type = E820_NVS;
152 break;
153 case EFI_UNUSABLE_MEMORY:
154 e820_type = E820_UNUSABLE;
155 break;
156 default:
157 /*
158 * EFI_RESERVED_TYPE EFI_RUNTIME_SERVICES_CODE
159 * EFI_RUNTIME_SERVICES_DATA EFI_MEMORY_MAPPED_IO
160 * EFI_MEMORY_MAPPED_IO_PORT_SPACE EFI_PAL_CODE
161 */
162 e820_type = E820_RESERVED;
163 break;
164 }
165 e820_add_region(start, size, e820_type);
166 }
167 sanitize_e820_map(e820.map, ARRAY_SIZE(e820.map), &e820.nr_map);
168 }
169
efi_memblock_x86_reserve_range(void)170 int __init efi_memblock_x86_reserve_range(void)
171 {
172 struct efi_info *e = &boot_params.efi_info;
173 unsigned long pmap;
174
175 if (efi_enabled(EFI_PARAVIRT))
176 return 0;
177
178 #ifdef CONFIG_X86_32
179 /* Can't handle data above 4GB at this time */
180 if (e->efi_memmap_hi) {
181 pr_err("Memory map is above 4GB, disabling EFI.\n");
182 return -EINVAL;
183 }
184 pmap = e->efi_memmap;
185 #else
186 pmap = (e->efi_memmap | ((__u64)e->efi_memmap_hi << 32));
187 #endif
188 memmap.phys_map = (void *)pmap;
189 memmap.nr_map = e->efi_memmap_size /
190 e->efi_memdesc_size;
191 memmap.desc_size = e->efi_memdesc_size;
192 memmap.desc_version = e->efi_memdesc_version;
193
194 memblock_reserve(pmap, memmap.nr_map * memmap.desc_size);
195
196 efi.memmap = &memmap;
197
198 return 0;
199 }
200
print_efi_memmap(void)201 static void __init print_efi_memmap(void)
202 {
203 #ifdef EFI_DEBUG
204 efi_memory_desc_t *md;
205 void *p;
206 int i;
207
208 for (p = memmap.map, i = 0;
209 p < memmap.map_end;
210 p += memmap.desc_size, i++) {
211 char buf[64];
212
213 md = p;
214 pr_info("mem%02u: %s range=[0x%016llx-0x%016llx) (%lluMB)\n",
215 i, efi_md_typeattr_format(buf, sizeof(buf), md),
216 md->phys_addr,
217 md->phys_addr + (md->num_pages << EFI_PAGE_SHIFT),
218 (md->num_pages >> (20 - EFI_PAGE_SHIFT)));
219 }
220 #endif /* EFI_DEBUG */
221 }
222
efi_unmap_memmap(void)223 void __init efi_unmap_memmap(void)
224 {
225 clear_bit(EFI_MEMMAP, &efi.flags);
226 if (memmap.map) {
227 early_memunmap(memmap.map, memmap.nr_map * memmap.desc_size);
228 memmap.map = NULL;
229 }
230 }
231
efi_systab_init(void * phys)232 static int __init efi_systab_init(void *phys)
233 {
234 if (efi_enabled(EFI_64BIT)) {
235 efi_system_table_64_t *systab64;
236 struct efi_setup_data *data = NULL;
237 u64 tmp = 0;
238
239 if (efi_setup) {
240 data = early_memremap(efi_setup, sizeof(*data));
241 if (!data)
242 return -ENOMEM;
243 }
244 systab64 = early_memremap((unsigned long)phys,
245 sizeof(*systab64));
246 if (systab64 == NULL) {
247 pr_err("Couldn't map the system table!\n");
248 if (data)
249 early_memunmap(data, sizeof(*data));
250 return -ENOMEM;
251 }
252
253 efi_systab.hdr = systab64->hdr;
254 efi_systab.fw_vendor = data ? (unsigned long)data->fw_vendor :
255 systab64->fw_vendor;
256 tmp |= data ? data->fw_vendor : systab64->fw_vendor;
257 efi_systab.fw_revision = systab64->fw_revision;
258 efi_systab.con_in_handle = systab64->con_in_handle;
259 tmp |= systab64->con_in_handle;
260 efi_systab.con_in = systab64->con_in;
261 tmp |= systab64->con_in;
262 efi_systab.con_out_handle = systab64->con_out_handle;
263 tmp |= systab64->con_out_handle;
264 efi_systab.con_out = systab64->con_out;
265 tmp |= systab64->con_out;
266 efi_systab.stderr_handle = systab64->stderr_handle;
267 tmp |= systab64->stderr_handle;
268 efi_systab.stderr = systab64->stderr;
269 tmp |= systab64->stderr;
270 efi_systab.runtime = data ?
271 (void *)(unsigned long)data->runtime :
272 (void *)(unsigned long)systab64->runtime;
273 tmp |= data ? data->runtime : systab64->runtime;
274 efi_systab.boottime = (void *)(unsigned long)systab64->boottime;
275 tmp |= systab64->boottime;
276 efi_systab.nr_tables = systab64->nr_tables;
277 efi_systab.tables = data ? (unsigned long)data->tables :
278 systab64->tables;
279 tmp |= data ? data->tables : systab64->tables;
280
281 early_memunmap(systab64, sizeof(*systab64));
282 if (data)
283 early_memunmap(data, sizeof(*data));
284 #ifdef CONFIG_X86_32
285 if (tmp >> 32) {
286 pr_err("EFI data located above 4GB, disabling EFI.\n");
287 return -EINVAL;
288 }
289 #endif
290 } else {
291 efi_system_table_32_t *systab32;
292
293 systab32 = early_memremap((unsigned long)phys,
294 sizeof(*systab32));
295 if (systab32 == NULL) {
296 pr_err("Couldn't map the system table!\n");
297 return -ENOMEM;
298 }
299
300 efi_systab.hdr = systab32->hdr;
301 efi_systab.fw_vendor = systab32->fw_vendor;
302 efi_systab.fw_revision = systab32->fw_revision;
303 efi_systab.con_in_handle = systab32->con_in_handle;
304 efi_systab.con_in = systab32->con_in;
305 efi_systab.con_out_handle = systab32->con_out_handle;
306 efi_systab.con_out = systab32->con_out;
307 efi_systab.stderr_handle = systab32->stderr_handle;
308 efi_systab.stderr = systab32->stderr;
309 efi_systab.runtime = (void *)(unsigned long)systab32->runtime;
310 efi_systab.boottime = (void *)(unsigned long)systab32->boottime;
311 efi_systab.nr_tables = systab32->nr_tables;
312 efi_systab.tables = systab32->tables;
313
314 early_memunmap(systab32, sizeof(*systab32));
315 }
316
317 efi.systab = &efi_systab;
318
319 /*
320 * Verify the EFI Table
321 */
322 if (efi.systab->hdr.signature != EFI_SYSTEM_TABLE_SIGNATURE) {
323 pr_err("System table signature incorrect!\n");
324 return -EINVAL;
325 }
326 if ((efi.systab->hdr.revision >> 16) == 0)
327 pr_err("Warning: System table version %d.%02d, expected 1.00 or greater!\n",
328 efi.systab->hdr.revision >> 16,
329 efi.systab->hdr.revision & 0xffff);
330
331 set_bit(EFI_SYSTEM_TABLES, &efi.flags);
332
333 return 0;
334 }
335
efi_runtime_init32(void)336 static int __init efi_runtime_init32(void)
337 {
338 efi_runtime_services_32_t *runtime;
339
340 runtime = early_memremap((unsigned long)efi.systab->runtime,
341 sizeof(efi_runtime_services_32_t));
342 if (!runtime) {
343 pr_err("Could not map the runtime service table!\n");
344 return -ENOMEM;
345 }
346
347 /*
348 * We will only need *early* access to the SetVirtualAddressMap
349 * EFI runtime service. All other runtime services will be called
350 * via the virtual mapping.
351 */
352 efi_phys.set_virtual_address_map =
353 (efi_set_virtual_address_map_t *)
354 (unsigned long)runtime->set_virtual_address_map;
355 early_memunmap(runtime, sizeof(efi_runtime_services_32_t));
356
357 return 0;
358 }
359
efi_runtime_init64(void)360 static int __init efi_runtime_init64(void)
361 {
362 efi_runtime_services_64_t *runtime;
363
364 runtime = early_memremap((unsigned long)efi.systab->runtime,
365 sizeof(efi_runtime_services_64_t));
366 if (!runtime) {
367 pr_err("Could not map the runtime service table!\n");
368 return -ENOMEM;
369 }
370
371 /*
372 * We will only need *early* access to the SetVirtualAddressMap
373 * EFI runtime service. All other runtime services will be called
374 * via the virtual mapping.
375 */
376 efi_phys.set_virtual_address_map =
377 (efi_set_virtual_address_map_t *)
378 (unsigned long)runtime->set_virtual_address_map;
379 early_memunmap(runtime, sizeof(efi_runtime_services_64_t));
380
381 return 0;
382 }
383
efi_runtime_init(void)384 static int __init efi_runtime_init(void)
385 {
386 int rv;
387
388 /*
389 * Check out the runtime services table. We need to map
390 * the runtime services table so that we can grab the physical
391 * address of several of the EFI runtime functions, needed to
392 * set the firmware into virtual mode.
393 *
394 * When EFI_PARAVIRT is in force then we could not map runtime
395 * service memory region because we do not have direct access to it.
396 * However, runtime services are available through proxy functions
397 * (e.g. in case of Xen dom0 EFI implementation they call special
398 * hypercall which executes relevant EFI functions) and that is why
399 * they are always enabled.
400 */
401
402 if (!efi_enabled(EFI_PARAVIRT)) {
403 if (efi_enabled(EFI_64BIT))
404 rv = efi_runtime_init64();
405 else
406 rv = efi_runtime_init32();
407
408 if (rv)
409 return rv;
410 }
411
412 set_bit(EFI_RUNTIME_SERVICES, &efi.flags);
413
414 return 0;
415 }
416
efi_memmap_init(void)417 static int __init efi_memmap_init(void)
418 {
419 if (efi_enabled(EFI_PARAVIRT))
420 return 0;
421
422 /* Map the EFI memory map */
423 memmap.map = early_memremap((unsigned long)memmap.phys_map,
424 memmap.nr_map * memmap.desc_size);
425 if (memmap.map == NULL) {
426 pr_err("Could not map the memory map!\n");
427 return -ENOMEM;
428 }
429 memmap.map_end = memmap.map + (memmap.nr_map * memmap.desc_size);
430
431 if (add_efi_memmap)
432 do_add_efi_memmap();
433
434 set_bit(EFI_MEMMAP, &efi.flags);
435
436 return 0;
437 }
438
efi_init(void)439 void __init efi_init(void)
440 {
441 efi_char16_t *c16;
442 char vendor[100] = "unknown";
443 int i = 0;
444 void *tmp;
445
446 #ifdef CONFIG_X86_32
447 if (boot_params.efi_info.efi_systab_hi ||
448 boot_params.efi_info.efi_memmap_hi) {
449 pr_info("Table located above 4GB, disabling EFI.\n");
450 return;
451 }
452 efi_phys.systab = (efi_system_table_t *)boot_params.efi_info.efi_systab;
453 #else
454 efi_phys.systab = (efi_system_table_t *)
455 (boot_params.efi_info.efi_systab |
456 ((__u64)boot_params.efi_info.efi_systab_hi<<32));
457 #endif
458
459 if (efi_systab_init(efi_phys.systab))
460 return;
461
462 efi.config_table = (unsigned long)efi.systab->tables;
463 efi.fw_vendor = (unsigned long)efi.systab->fw_vendor;
464 efi.runtime = (unsigned long)efi.systab->runtime;
465
466 /*
467 * Show what we know for posterity
468 */
469 c16 = tmp = early_memremap(efi.systab->fw_vendor, 2);
470 if (c16) {
471 for (i = 0; i < sizeof(vendor) - 1 && *c16; ++i)
472 vendor[i] = *c16++;
473 vendor[i] = '\0';
474 } else
475 pr_err("Could not map the firmware vendor!\n");
476 early_memunmap(tmp, 2);
477
478 pr_info("EFI v%u.%.02u by %s\n",
479 efi.systab->hdr.revision >> 16,
480 efi.systab->hdr.revision & 0xffff, vendor);
481
482 if (efi_reuse_config(efi.systab->tables, efi.systab->nr_tables))
483 return;
484
485 if (efi_config_init(arch_tables))
486 return;
487
488 /*
489 * Note: We currently don't support runtime services on an EFI
490 * that doesn't match the kernel 32/64-bit mode.
491 */
492
493 if (!efi_runtime_supported())
494 pr_info("No EFI runtime due to 32/64-bit mismatch with kernel\n");
495 else {
496 if (efi_runtime_disabled() || efi_runtime_init())
497 return;
498 }
499 if (efi_memmap_init())
500 return;
501
502 if (efi_enabled(EFI_DBG))
503 print_efi_memmap();
504 }
505
efi_late_init(void)506 void __init efi_late_init(void)
507 {
508 efi_bgrt_init();
509 }
510
efi_set_executable(efi_memory_desc_t * md,bool executable)511 void __init efi_set_executable(efi_memory_desc_t *md, bool executable)
512 {
513 u64 addr, npages;
514
515 addr = md->virt_addr;
516 npages = md->num_pages;
517
518 memrange_efi_to_native(&addr, &npages);
519
520 if (executable)
521 set_memory_x(addr, npages);
522 else
523 set_memory_nx(addr, npages);
524 }
525
runtime_code_page_mkexec(void)526 void __init runtime_code_page_mkexec(void)
527 {
528 efi_memory_desc_t *md;
529 void *p;
530
531 /* Make EFI runtime service code area executable */
532 for (p = memmap.map; p < memmap.map_end; p += memmap.desc_size) {
533 md = p;
534
535 if (md->type != EFI_RUNTIME_SERVICES_CODE)
536 continue;
537
538 efi_set_executable(md, true);
539 }
540 }
541
efi_memory_uc(u64 addr,unsigned long size)542 void __init efi_memory_uc(u64 addr, unsigned long size)
543 {
544 unsigned long page_shift = 1UL << EFI_PAGE_SHIFT;
545 u64 npages;
546
547 npages = round_up(size, page_shift) / page_shift;
548 memrange_efi_to_native(&addr, &npages);
549 set_memory_uc(addr, npages);
550 }
551
old_map_region(efi_memory_desc_t * md)552 void __init old_map_region(efi_memory_desc_t *md)
553 {
554 u64 start_pfn, end_pfn, end;
555 unsigned long size;
556 void *va;
557
558 start_pfn = PFN_DOWN(md->phys_addr);
559 size = md->num_pages << PAGE_SHIFT;
560 end = md->phys_addr + size;
561 end_pfn = PFN_UP(end);
562
563 if (pfn_range_is_mapped(start_pfn, end_pfn)) {
564 va = __va(md->phys_addr);
565
566 if (!(md->attribute & EFI_MEMORY_WB))
567 efi_memory_uc((u64)(unsigned long)va, size);
568 } else
569 va = efi_ioremap(md->phys_addr, size,
570 md->type, md->attribute);
571
572 md->virt_addr = (u64) (unsigned long) va;
573 if (!va)
574 pr_err("ioremap of 0x%llX failed!\n",
575 (unsigned long long)md->phys_addr);
576 }
577
578 /* Merge contiguous regions of the same type and attribute */
efi_merge_regions(void)579 static void __init efi_merge_regions(void)
580 {
581 void *p;
582 efi_memory_desc_t *md, *prev_md = NULL;
583
584 for (p = memmap.map; p < memmap.map_end; p += memmap.desc_size) {
585 u64 prev_size;
586 md = p;
587
588 if (!prev_md) {
589 prev_md = md;
590 continue;
591 }
592
593 if (prev_md->type != md->type ||
594 prev_md->attribute != md->attribute) {
595 prev_md = md;
596 continue;
597 }
598
599 prev_size = prev_md->num_pages << EFI_PAGE_SHIFT;
600
601 if (md->phys_addr == (prev_md->phys_addr + prev_size)) {
602 prev_md->num_pages += md->num_pages;
603 md->type = EFI_RESERVED_TYPE;
604 md->attribute = 0;
605 continue;
606 }
607 prev_md = md;
608 }
609 }
610
get_systab_virt_addr(efi_memory_desc_t * md)611 static void __init get_systab_virt_addr(efi_memory_desc_t *md)
612 {
613 unsigned long size;
614 u64 end, systab;
615
616 size = md->num_pages << EFI_PAGE_SHIFT;
617 end = md->phys_addr + size;
618 systab = (u64)(unsigned long)efi_phys.systab;
619 if (md->phys_addr <= systab && systab < end) {
620 systab += md->virt_addr - md->phys_addr;
621 efi.systab = (efi_system_table_t *)(unsigned long)systab;
622 }
623 }
624
save_runtime_map(void)625 static void __init save_runtime_map(void)
626 {
627 #ifdef CONFIG_KEXEC
628 efi_memory_desc_t *md;
629 void *tmp, *p, *q = NULL;
630 int count = 0;
631
632 if (efi_enabled(EFI_OLD_MEMMAP))
633 return;
634
635 for (p = memmap.map; p < memmap.map_end; p += memmap.desc_size) {
636 md = p;
637
638 if (!(md->attribute & EFI_MEMORY_RUNTIME) ||
639 (md->type == EFI_BOOT_SERVICES_CODE) ||
640 (md->type == EFI_BOOT_SERVICES_DATA))
641 continue;
642 tmp = krealloc(q, (count + 1) * memmap.desc_size, GFP_KERNEL);
643 if (!tmp)
644 goto out;
645 q = tmp;
646
647 memcpy(q + count * memmap.desc_size, md, memmap.desc_size);
648 count++;
649 }
650
651 efi_runtime_map_setup(q, count, memmap.desc_size);
652 return;
653
654 out:
655 kfree(q);
656 pr_err("Error saving runtime map, efi runtime on kexec non-functional!!\n");
657 #endif
658 }
659
realloc_pages(void * old_memmap,int old_shift)660 static void *realloc_pages(void *old_memmap, int old_shift)
661 {
662 void *ret;
663
664 ret = (void *)__get_free_pages(GFP_KERNEL, old_shift + 1);
665 if (!ret)
666 goto out;
667
668 /*
669 * A first-time allocation doesn't have anything to copy.
670 */
671 if (!old_memmap)
672 return ret;
673
674 memcpy(ret, old_memmap, PAGE_SIZE << old_shift);
675
676 out:
677 free_pages((unsigned long)old_memmap, old_shift);
678 return ret;
679 }
680
681 /*
682 * Iterate the EFI memory map in reverse order because the regions
683 * will be mapped top-down. The end result is the same as if we had
684 * mapped things forward, but doesn't require us to change the
685 * existing implementation of efi_map_region().
686 */
efi_map_next_entry_reverse(void * entry)687 static inline void *efi_map_next_entry_reverse(void *entry)
688 {
689 /* Initial call */
690 if (!entry)
691 return memmap.map_end - memmap.desc_size;
692
693 entry -= memmap.desc_size;
694 if (entry < memmap.map)
695 return NULL;
696
697 return entry;
698 }
699
700 /*
701 * efi_map_next_entry - Return the next EFI memory map descriptor
702 * @entry: Previous EFI memory map descriptor
703 *
704 * This is a helper function to iterate over the EFI memory map, which
705 * we do in different orders depending on the current configuration.
706 *
707 * To begin traversing the memory map @entry must be %NULL.
708 *
709 * Returns %NULL when we reach the end of the memory map.
710 */
efi_map_next_entry(void * entry)711 static void *efi_map_next_entry(void *entry)
712 {
713 if (!efi_enabled(EFI_OLD_MEMMAP) && efi_enabled(EFI_64BIT)) {
714 /*
715 * Starting in UEFI v2.5 the EFI_PROPERTIES_TABLE
716 * config table feature requires us to map all entries
717 * in the same order as they appear in the EFI memory
718 * map. That is to say, entry N must have a lower
719 * virtual address than entry N+1. This is because the
720 * firmware toolchain leaves relative references in
721 * the code/data sections, which are split and become
722 * separate EFI memory regions. Mapping things
723 * out-of-order leads to the firmware accessing
724 * unmapped addresses.
725 *
726 * Since we need to map things this way whether or not
727 * the kernel actually makes use of
728 * EFI_PROPERTIES_TABLE, let's just switch to this
729 * scheme by default for 64-bit.
730 */
731 return efi_map_next_entry_reverse(entry);
732 }
733
734 /* Initial call */
735 if (!entry)
736 return memmap.map;
737
738 entry += memmap.desc_size;
739 if (entry >= memmap.map_end)
740 return NULL;
741
742 return entry;
743 }
744
745 /*
746 * Map the efi memory ranges of the runtime services and update new_mmap with
747 * virtual addresses.
748 */
efi_map_regions(int * count,int * pg_shift)749 static void * __init efi_map_regions(int *count, int *pg_shift)
750 {
751 void *p, *new_memmap = NULL;
752 unsigned long left = 0;
753 efi_memory_desc_t *md;
754
755 p = NULL;
756 while ((p = efi_map_next_entry(p))) {
757 md = p;
758 if (!(md->attribute & EFI_MEMORY_RUNTIME)) {
759 #ifdef CONFIG_X86_64
760 if (md->type != EFI_BOOT_SERVICES_CODE &&
761 md->type != EFI_BOOT_SERVICES_DATA)
762 #endif
763 continue;
764 }
765
766 efi_map_region(md);
767 get_systab_virt_addr(md);
768
769 if (left < memmap.desc_size) {
770 new_memmap = realloc_pages(new_memmap, *pg_shift);
771 if (!new_memmap)
772 return NULL;
773
774 left += PAGE_SIZE << *pg_shift;
775 (*pg_shift)++;
776 }
777
778 memcpy(new_memmap + (*count * memmap.desc_size), md,
779 memmap.desc_size);
780
781 left -= memmap.desc_size;
782 (*count)++;
783 }
784
785 return new_memmap;
786 }
787
kexec_enter_virtual_mode(void)788 static void __init kexec_enter_virtual_mode(void)
789 {
790 #ifdef CONFIG_KEXEC
791 efi_memory_desc_t *md;
792 void *p;
793
794 efi.systab = NULL;
795
796 /*
797 * We don't do virtual mode, since we don't do runtime services, on
798 * non-native EFI
799 */
800 if (!efi_is_native()) {
801 efi_unmap_memmap();
802 clear_bit(EFI_RUNTIME_SERVICES, &efi.flags);
803 return;
804 }
805
806 /*
807 * Map efi regions which were passed via setup_data. The virt_addr is a
808 * fixed addr which was used in first kernel of a kexec boot.
809 */
810 for (p = memmap.map; p < memmap.map_end; p += memmap.desc_size) {
811 md = p;
812 efi_map_region_fixed(md); /* FIXME: add error handling */
813 get_systab_virt_addr(md);
814 }
815
816 save_runtime_map();
817
818 BUG_ON(!efi.systab);
819
820 efi_sync_low_kernel_mappings();
821
822 /*
823 * Now that EFI is in virtual mode, update the function
824 * pointers in the runtime service table to the new virtual addresses.
825 *
826 * Call EFI services through wrapper functions.
827 */
828 efi.runtime_version = efi_systab.hdr.revision;
829
830 efi_native_runtime_setup();
831
832 efi.set_virtual_address_map = NULL;
833
834 if (efi_enabled(EFI_OLD_MEMMAP) && (__supported_pte_mask & _PAGE_NX))
835 runtime_code_page_mkexec();
836
837 /* clean DUMMY object */
838 efi_delete_dummy_variable();
839 #endif
840 }
841
842 /*
843 * This function will switch the EFI runtime services to virtual mode.
844 * Essentially, we look through the EFI memmap and map every region that
845 * has the runtime attribute bit set in its memory descriptor into the
846 * ->trampoline_pgd page table using a top-down VA allocation scheme.
847 *
848 * The old method which used to update that memory descriptor with the
849 * virtual address obtained from ioremap() is still supported when the
850 * kernel is booted with efi=old_map on its command line. Same old
851 * method enabled the runtime services to be called without having to
852 * thunk back into physical mode for every invocation.
853 *
854 * The new method does a pagetable switch in a preemption-safe manner
855 * so that we're in a different address space when calling a runtime
856 * function. For function arguments passing we do copy the PGDs of the
857 * kernel page table into ->trampoline_pgd prior to each call.
858 *
859 * Specially for kexec boot, efi runtime maps in previous kernel should
860 * be passed in via setup_data. In that case runtime ranges will be mapped
861 * to the same virtual addresses as the first kernel, see
862 * kexec_enter_virtual_mode().
863 */
__efi_enter_virtual_mode(void)864 static void __init __efi_enter_virtual_mode(void)
865 {
866 int count = 0, pg_shift = 0;
867 void *new_memmap = NULL;
868 efi_status_t status;
869
870 efi.systab = NULL;
871
872 efi_merge_regions();
873 new_memmap = efi_map_regions(&count, &pg_shift);
874 if (!new_memmap) {
875 pr_err("Error reallocating memory, EFI runtime non-functional!\n");
876 clear_bit(EFI_RUNTIME_SERVICES, &efi.flags);
877 return;
878 }
879
880 save_runtime_map();
881
882 BUG_ON(!efi.systab);
883
884 if (efi_setup_page_tables(__pa(new_memmap), 1 << pg_shift)) {
885 clear_bit(EFI_RUNTIME_SERVICES, &efi.flags);
886 return;
887 }
888
889 efi_sync_low_kernel_mappings();
890 efi_dump_pagetable();
891
892 if (efi_is_native()) {
893 status = phys_efi_set_virtual_address_map(
894 memmap.desc_size * count,
895 memmap.desc_size,
896 memmap.desc_version,
897 (efi_memory_desc_t *)__pa(new_memmap));
898 } else {
899 status = efi_thunk_set_virtual_address_map(
900 efi_phys.set_virtual_address_map,
901 memmap.desc_size * count,
902 memmap.desc_size,
903 memmap.desc_version,
904 (efi_memory_desc_t *)__pa(new_memmap));
905 }
906
907 if (status != EFI_SUCCESS) {
908 pr_alert("Unable to switch EFI into virtual mode (status=%lx)!\n",
909 status);
910 panic("EFI call to SetVirtualAddressMap() failed!");
911 }
912
913 /*
914 * Now that EFI is in virtual mode, update the function
915 * pointers in the runtime service table to the new virtual addresses.
916 *
917 * Call EFI services through wrapper functions.
918 */
919 efi.runtime_version = efi_systab.hdr.revision;
920
921 if (efi_is_native())
922 efi_native_runtime_setup();
923 else
924 efi_thunk_runtime_setup();
925
926 efi.set_virtual_address_map = NULL;
927
928 efi_runtime_mkexec();
929
930 /*
931 * We mapped the descriptor array into the EFI pagetable above but we're
932 * not unmapping it here. Here's why:
933 *
934 * We're copying select PGDs from the kernel page table to the EFI page
935 * table and when we do so and make changes to those PGDs like unmapping
936 * stuff from them, those changes appear in the kernel page table and we
937 * go boom.
938 *
939 * From setup_real_mode():
940 *
941 * ...
942 * trampoline_pgd[0] = init_level4_pgt[pgd_index(__PAGE_OFFSET)].pgd;
943 *
944 * In this particular case, our allocation is in PGD 0 of the EFI page
945 * table but we've copied that PGD from PGD[272] of the EFI page table:
946 *
947 * pgd_index(__PAGE_OFFSET = 0xffff880000000000) = 272
948 *
949 * where the direct memory mapping in kernel space is.
950 *
951 * new_memmap's VA comes from that direct mapping and thus clearing it,
952 * it would get cleared in the kernel page table too.
953 *
954 * efi_cleanup_page_tables(__pa(new_memmap), 1 << pg_shift);
955 */
956 free_pages((unsigned long)new_memmap, pg_shift);
957
958 /* clean DUMMY object */
959 efi_delete_dummy_variable();
960 }
961
efi_enter_virtual_mode(void)962 void __init efi_enter_virtual_mode(void)
963 {
964 if (efi_enabled(EFI_PARAVIRT))
965 return;
966
967 if (efi_setup)
968 kexec_enter_virtual_mode();
969 else
970 __efi_enter_virtual_mode();
971 }
972
973 /*
974 * Convenience functions to obtain memory types and attributes
975 */
efi_mem_type(unsigned long phys_addr)976 u32 efi_mem_type(unsigned long phys_addr)
977 {
978 efi_memory_desc_t *md;
979 void *p;
980
981 if (!efi_enabled(EFI_MEMMAP))
982 return 0;
983
984 for (p = memmap.map; p < memmap.map_end; p += memmap.desc_size) {
985 md = p;
986 if ((md->phys_addr <= phys_addr) &&
987 (phys_addr < (md->phys_addr +
988 (md->num_pages << EFI_PAGE_SHIFT))))
989 return md->type;
990 }
991 return 0;
992 }
993
efi_mem_attributes(unsigned long phys_addr)994 u64 efi_mem_attributes(unsigned long phys_addr)
995 {
996 efi_memory_desc_t *md;
997 void *p;
998
999 if (!efi_enabled(EFI_MEMMAP))
1000 return 0;
1001
1002 for (p = memmap.map; p < memmap.map_end; p += memmap.desc_size) {
1003 md = p;
1004 if ((md->phys_addr <= phys_addr) &&
1005 (phys_addr < (md->phys_addr +
1006 (md->num_pages << EFI_PAGE_SHIFT))))
1007 return md->attribute;
1008 }
1009 return 0;
1010 }
1011
arch_parse_efi_cmdline(char * str)1012 static int __init arch_parse_efi_cmdline(char *str)
1013 {
1014 if (!str) {
1015 pr_warn("need at least one option\n");
1016 return -EINVAL;
1017 }
1018
1019 if (parse_option_str(str, "old_map"))
1020 set_bit(EFI_OLD_MEMMAP, &efi.flags);
1021 if (parse_option_str(str, "debug"))
1022 set_bit(EFI_DBG, &efi.flags);
1023
1024 return 0;
1025 }
1026 early_param("efi", arch_parse_efi_cmdline);
1027