1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * Common EFI (Extensible Firmware Interface) support functions
4 * Based on Extensible Firmware Interface Specification version 1.0
5 *
6 * Copyright (C) 1999 VA Linux Systems
7 * Copyright (C) 1999 Walt Drummond <drummond@valinux.com>
8 * Copyright (C) 1999-2002 Hewlett-Packard Co.
9 * David Mosberger-Tang <davidm@hpl.hp.com>
10 * Stephane Eranian <eranian@hpl.hp.com>
11 * Copyright (C) 2005-2008 Intel Co.
12 * Fenghua Yu <fenghua.yu@intel.com>
13 * Bibo Mao <bibo.mao@intel.com>
14 * Chandramouli Narayanan <mouli@linux.intel.com>
15 * Huang Ying <ying.huang@intel.com>
16 * Copyright (C) 2013 SuSE Labs
17 * Borislav Petkov <bp@suse.de> - runtime services VA mapping
18 *
19 * Copied from efi_32.c to eliminate the duplicated code between EFI
20 * 32/64 support code. --ying 2007-10-26
21 *
22 * All EFI Runtime Services are not implemented yet as EFI only
23 * supports physical mode addressing on SoftSDV. This is to be fixed
24 * in a future version. --drummond 1999-07-20
25 *
26 * Implemented EFI runtime services and virtual mode calls. --davidm
27 *
28 * Goutham Rao: <goutham.rao@intel.com>
29 * Skip non-WB memory and ignore empty memory ranges.
30 */
31
32 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
33
34 #include <linux/kernel.h>
35 #include <linux/init.h>
36 #include <linux/efi.h>
37 #include <linux/efi-bgrt.h>
38 #include <linux/export.h>
39 #include <linux/bootmem.h>
40 #include <linux/slab.h>
41 #include <linux/memblock.h>
42 #include <linux/spinlock.h>
43 #include <linux/uaccess.h>
44 #include <linux/time.h>
45 #include <linux/io.h>
46 #include <linux/reboot.h>
47 #include <linux/bcd.h>
48
49 #include <asm/setup.h>
50 #include <asm/efi.h>
51 #include <asm/e820/api.h>
52 #include <asm/time.h>
53 #include <asm/set_memory.h>
54 #include <asm/tlbflush.h>
55 #include <asm/x86_init.h>
56 #include <asm/uv/uv.h>
57
58 static struct efi efi_phys __initdata;
59 static efi_system_table_t efi_systab __initdata;
60
61 static efi_config_table_type_t arch_tables[] __initdata = {
62 #ifdef CONFIG_X86_UV
63 {UV_SYSTEM_TABLE_GUID, "UVsystab", &efi.uv_systab},
64 #endif
65 {NULL_GUID, NULL, NULL},
66 };
67
68 u64 efi_setup; /* efi setup_data physical address */
69
70 static int add_efi_memmap __initdata;
setup_add_efi_memmap(char * arg)71 static int __init setup_add_efi_memmap(char *arg)
72 {
73 add_efi_memmap = 1;
74 return 0;
75 }
76 early_param("add_efi_memmap", setup_add_efi_memmap);
77
phys_efi_set_virtual_address_map(unsigned long memory_map_size,unsigned long descriptor_size,u32 descriptor_version,efi_memory_desc_t * virtual_map)78 static efi_status_t __init phys_efi_set_virtual_address_map(
79 unsigned long memory_map_size,
80 unsigned long descriptor_size,
81 u32 descriptor_version,
82 efi_memory_desc_t *virtual_map)
83 {
84 efi_status_t status;
85 unsigned long flags;
86 pgd_t *save_pgd;
87
88 save_pgd = efi_call_phys_prolog();
89
90 /* Disable interrupts around EFI calls: */
91 local_irq_save(flags);
92 status = efi_call_phys(efi_phys.set_virtual_address_map,
93 memory_map_size, descriptor_size,
94 descriptor_version, virtual_map);
95 local_irq_restore(flags);
96
97 efi_call_phys_epilog(save_pgd);
98
99 return status;
100 }
101
efi_find_mirror(void)102 void __init efi_find_mirror(void)
103 {
104 efi_memory_desc_t *md;
105 u64 mirror_size = 0, total_size = 0;
106
107 for_each_efi_memory_desc(md) {
108 unsigned long long start = md->phys_addr;
109 unsigned long long size = md->num_pages << EFI_PAGE_SHIFT;
110
111 total_size += size;
112 if (md->attribute & EFI_MEMORY_MORE_RELIABLE) {
113 memblock_mark_mirror(start, size);
114 mirror_size += size;
115 }
116 }
117 if (mirror_size)
118 pr_info("Memory: %lldM/%lldM mirrored memory\n",
119 mirror_size>>20, total_size>>20);
120 }
121
122 /*
123 * Tell the kernel about the EFI memory map. This might include
124 * more than the max 128 entries that can fit in the e820 legacy
125 * (zeropage) memory map.
126 */
127
do_add_efi_memmap(void)128 static void __init do_add_efi_memmap(void)
129 {
130 efi_memory_desc_t *md;
131
132 for_each_efi_memory_desc(md) {
133 unsigned long long start = md->phys_addr;
134 unsigned long long size = md->num_pages << EFI_PAGE_SHIFT;
135 int e820_type;
136
137 switch (md->type) {
138 case EFI_LOADER_CODE:
139 case EFI_LOADER_DATA:
140 case EFI_BOOT_SERVICES_CODE:
141 case EFI_BOOT_SERVICES_DATA:
142 case EFI_CONVENTIONAL_MEMORY:
143 if (md->attribute & EFI_MEMORY_WB)
144 e820_type = E820_TYPE_RAM;
145 else
146 e820_type = E820_TYPE_RESERVED;
147 break;
148 case EFI_ACPI_RECLAIM_MEMORY:
149 e820_type = E820_TYPE_ACPI;
150 break;
151 case EFI_ACPI_MEMORY_NVS:
152 e820_type = E820_TYPE_NVS;
153 break;
154 case EFI_UNUSABLE_MEMORY:
155 e820_type = E820_TYPE_UNUSABLE;
156 break;
157 case EFI_PERSISTENT_MEMORY:
158 e820_type = E820_TYPE_PMEM;
159 break;
160 default:
161 /*
162 * EFI_RESERVED_TYPE EFI_RUNTIME_SERVICES_CODE
163 * EFI_RUNTIME_SERVICES_DATA EFI_MEMORY_MAPPED_IO
164 * EFI_MEMORY_MAPPED_IO_PORT_SPACE EFI_PAL_CODE
165 */
166 e820_type = E820_TYPE_RESERVED;
167 break;
168 }
169 e820__range_add(start, size, e820_type);
170 }
171 e820__update_table(e820_table);
172 }
173
efi_memblock_x86_reserve_range(void)174 int __init efi_memblock_x86_reserve_range(void)
175 {
176 struct efi_info *e = &boot_params.efi_info;
177 struct efi_memory_map_data data;
178 phys_addr_t pmap;
179 int rv;
180
181 if (efi_enabled(EFI_PARAVIRT))
182 return 0;
183
184 #ifdef CONFIG_X86_32
185 /* Can't handle data above 4GB at this time */
186 if (e->efi_memmap_hi) {
187 pr_err("Memory map is above 4GB, disabling EFI.\n");
188 return -EINVAL;
189 }
190 pmap = e->efi_memmap;
191 #else
192 pmap = (e->efi_memmap | ((__u64)e->efi_memmap_hi << 32));
193 #endif
194 data.phys_map = pmap;
195 data.size = e->efi_memmap_size;
196 data.desc_size = e->efi_memdesc_size;
197 data.desc_version = e->efi_memdesc_version;
198
199 rv = efi_memmap_init_early(&data);
200 if (rv)
201 return rv;
202
203 if (add_efi_memmap)
204 do_add_efi_memmap();
205
206 WARN(efi.memmap.desc_version != 1,
207 "Unexpected EFI_MEMORY_DESCRIPTOR version %ld",
208 efi.memmap.desc_version);
209
210 memblock_reserve(pmap, efi.memmap.nr_map * efi.memmap.desc_size);
211
212 return 0;
213 }
214
215 #define OVERFLOW_ADDR_SHIFT (64 - EFI_PAGE_SHIFT)
216 #define OVERFLOW_ADDR_MASK (U64_MAX << OVERFLOW_ADDR_SHIFT)
217 #define U64_HIGH_BIT (~(U64_MAX >> 1))
218
efi_memmap_entry_valid(const efi_memory_desc_t * md,int i)219 static bool __init efi_memmap_entry_valid(const efi_memory_desc_t *md, int i)
220 {
221 u64 end = (md->num_pages << EFI_PAGE_SHIFT) + md->phys_addr - 1;
222 u64 end_hi = 0;
223 char buf[64];
224
225 if (md->num_pages == 0) {
226 end = 0;
227 } else if (md->num_pages > EFI_PAGES_MAX ||
228 EFI_PAGES_MAX - md->num_pages <
229 (md->phys_addr >> EFI_PAGE_SHIFT)) {
230 end_hi = (md->num_pages & OVERFLOW_ADDR_MASK)
231 >> OVERFLOW_ADDR_SHIFT;
232
233 if ((md->phys_addr & U64_HIGH_BIT) && !(end & U64_HIGH_BIT))
234 end_hi += 1;
235 } else {
236 return true;
237 }
238
239 pr_warn_once(FW_BUG "Invalid EFI memory map entries:\n");
240
241 if (end_hi) {
242 pr_warn("mem%02u: %s range=[0x%016llx-0x%llx%016llx] (invalid)\n",
243 i, efi_md_typeattr_format(buf, sizeof(buf), md),
244 md->phys_addr, end_hi, end);
245 } else {
246 pr_warn("mem%02u: %s range=[0x%016llx-0x%016llx] (invalid)\n",
247 i, efi_md_typeattr_format(buf, sizeof(buf), md),
248 md->phys_addr, end);
249 }
250 return false;
251 }
252
efi_clean_memmap(void)253 static void __init efi_clean_memmap(void)
254 {
255 efi_memory_desc_t *out = efi.memmap.map;
256 const efi_memory_desc_t *in = out;
257 const efi_memory_desc_t *end = efi.memmap.map_end;
258 int i, n_removal;
259
260 for (i = n_removal = 0; in < end; i++) {
261 if (efi_memmap_entry_valid(in, i)) {
262 if (out != in)
263 memcpy(out, in, efi.memmap.desc_size);
264 out = (void *)out + efi.memmap.desc_size;
265 } else {
266 n_removal++;
267 }
268 in = (void *)in + efi.memmap.desc_size;
269 }
270
271 if (n_removal > 0) {
272 u64 size = efi.memmap.nr_map - n_removal;
273
274 pr_warn("Removing %d invalid memory map entries.\n", n_removal);
275 efi_memmap_install(efi.memmap.phys_map, size);
276 }
277 }
278
efi_print_memmap(void)279 void __init efi_print_memmap(void)
280 {
281 efi_memory_desc_t *md;
282 int i = 0;
283
284 for_each_efi_memory_desc(md) {
285 char buf[64];
286
287 pr_info("mem%02u: %s range=[0x%016llx-0x%016llx] (%lluMB)\n",
288 i++, efi_md_typeattr_format(buf, sizeof(buf), md),
289 md->phys_addr,
290 md->phys_addr + (md->num_pages << EFI_PAGE_SHIFT) - 1,
291 (md->num_pages >> (20 - EFI_PAGE_SHIFT)));
292 }
293 }
294
efi_systab_init(void * phys)295 static int __init efi_systab_init(void *phys)
296 {
297 if (efi_enabled(EFI_64BIT)) {
298 efi_system_table_64_t *systab64;
299 struct efi_setup_data *data = NULL;
300 u64 tmp = 0;
301
302 if (efi_setup) {
303 data = early_memremap(efi_setup, sizeof(*data));
304 if (!data)
305 return -ENOMEM;
306 }
307 systab64 = early_memremap((unsigned long)phys,
308 sizeof(*systab64));
309 if (systab64 == NULL) {
310 pr_err("Couldn't map the system table!\n");
311 if (data)
312 early_memunmap(data, sizeof(*data));
313 return -ENOMEM;
314 }
315
316 efi_systab.hdr = systab64->hdr;
317 efi_systab.fw_vendor = data ? (unsigned long)data->fw_vendor :
318 systab64->fw_vendor;
319 tmp |= data ? data->fw_vendor : systab64->fw_vendor;
320 efi_systab.fw_revision = systab64->fw_revision;
321 efi_systab.con_in_handle = systab64->con_in_handle;
322 tmp |= systab64->con_in_handle;
323 efi_systab.con_in = systab64->con_in;
324 tmp |= systab64->con_in;
325 efi_systab.con_out_handle = systab64->con_out_handle;
326 tmp |= systab64->con_out_handle;
327 efi_systab.con_out = systab64->con_out;
328 tmp |= systab64->con_out;
329 efi_systab.stderr_handle = systab64->stderr_handle;
330 tmp |= systab64->stderr_handle;
331 efi_systab.stderr = systab64->stderr;
332 tmp |= systab64->stderr;
333 efi_systab.runtime = data ?
334 (void *)(unsigned long)data->runtime :
335 (void *)(unsigned long)systab64->runtime;
336 tmp |= data ? data->runtime : systab64->runtime;
337 efi_systab.boottime = (void *)(unsigned long)systab64->boottime;
338 tmp |= systab64->boottime;
339 efi_systab.nr_tables = systab64->nr_tables;
340 efi_systab.tables = data ? (unsigned long)data->tables :
341 systab64->tables;
342 tmp |= data ? data->tables : systab64->tables;
343
344 early_memunmap(systab64, sizeof(*systab64));
345 if (data)
346 early_memunmap(data, sizeof(*data));
347 #ifdef CONFIG_X86_32
348 if (tmp >> 32) {
349 pr_err("EFI data located above 4GB, disabling EFI.\n");
350 return -EINVAL;
351 }
352 #endif
353 } else {
354 efi_system_table_32_t *systab32;
355
356 systab32 = early_memremap((unsigned long)phys,
357 sizeof(*systab32));
358 if (systab32 == NULL) {
359 pr_err("Couldn't map the system table!\n");
360 return -ENOMEM;
361 }
362
363 efi_systab.hdr = systab32->hdr;
364 efi_systab.fw_vendor = systab32->fw_vendor;
365 efi_systab.fw_revision = systab32->fw_revision;
366 efi_systab.con_in_handle = systab32->con_in_handle;
367 efi_systab.con_in = systab32->con_in;
368 efi_systab.con_out_handle = systab32->con_out_handle;
369 efi_systab.con_out = systab32->con_out;
370 efi_systab.stderr_handle = systab32->stderr_handle;
371 efi_systab.stderr = systab32->stderr;
372 efi_systab.runtime = (void *)(unsigned long)systab32->runtime;
373 efi_systab.boottime = (void *)(unsigned long)systab32->boottime;
374 efi_systab.nr_tables = systab32->nr_tables;
375 efi_systab.tables = systab32->tables;
376
377 early_memunmap(systab32, sizeof(*systab32));
378 }
379
380 efi.systab = &efi_systab;
381
382 /*
383 * Verify the EFI Table
384 */
385 if (efi.systab->hdr.signature != EFI_SYSTEM_TABLE_SIGNATURE) {
386 pr_err("System table signature incorrect!\n");
387 return -EINVAL;
388 }
389 if ((efi.systab->hdr.revision >> 16) == 0)
390 pr_err("Warning: System table version %d.%02d, expected 1.00 or greater!\n",
391 efi.systab->hdr.revision >> 16,
392 efi.systab->hdr.revision & 0xffff);
393
394 return 0;
395 }
396
efi_runtime_init32(void)397 static int __init efi_runtime_init32(void)
398 {
399 efi_runtime_services_32_t *runtime;
400
401 runtime = early_memremap((unsigned long)efi.systab->runtime,
402 sizeof(efi_runtime_services_32_t));
403 if (!runtime) {
404 pr_err("Could not map the runtime service table!\n");
405 return -ENOMEM;
406 }
407
408 /*
409 * We will only need *early* access to the SetVirtualAddressMap
410 * EFI runtime service. All other runtime services will be called
411 * via the virtual mapping.
412 */
413 efi_phys.set_virtual_address_map =
414 (efi_set_virtual_address_map_t *)
415 (unsigned long)runtime->set_virtual_address_map;
416 early_memunmap(runtime, sizeof(efi_runtime_services_32_t));
417
418 return 0;
419 }
420
efi_runtime_init64(void)421 static int __init efi_runtime_init64(void)
422 {
423 efi_runtime_services_64_t *runtime;
424
425 runtime = early_memremap((unsigned long)efi.systab->runtime,
426 sizeof(efi_runtime_services_64_t));
427 if (!runtime) {
428 pr_err("Could not map the runtime service table!\n");
429 return -ENOMEM;
430 }
431
432 /*
433 * We will only need *early* access to the SetVirtualAddressMap
434 * EFI runtime service. All other runtime services will be called
435 * via the virtual mapping.
436 */
437 efi_phys.set_virtual_address_map =
438 (efi_set_virtual_address_map_t *)
439 (unsigned long)runtime->set_virtual_address_map;
440 early_memunmap(runtime, sizeof(efi_runtime_services_64_t));
441
442 return 0;
443 }
444
efi_runtime_init(void)445 static int __init efi_runtime_init(void)
446 {
447 int rv;
448
449 /*
450 * Check out the runtime services table. We need to map
451 * the runtime services table so that we can grab the physical
452 * address of several of the EFI runtime functions, needed to
453 * set the firmware into virtual mode.
454 *
455 * When EFI_PARAVIRT is in force then we could not map runtime
456 * service memory region because we do not have direct access to it.
457 * However, runtime services are available through proxy functions
458 * (e.g. in case of Xen dom0 EFI implementation they call special
459 * hypercall which executes relevant EFI functions) and that is why
460 * they are always enabled.
461 */
462
463 if (!efi_enabled(EFI_PARAVIRT)) {
464 if (efi_enabled(EFI_64BIT))
465 rv = efi_runtime_init64();
466 else
467 rv = efi_runtime_init32();
468
469 if (rv)
470 return rv;
471 }
472
473 set_bit(EFI_RUNTIME_SERVICES, &efi.flags);
474
475 return 0;
476 }
477
efi_init(void)478 void __init efi_init(void)
479 {
480 efi_char16_t *c16;
481 char vendor[100] = "unknown";
482 int i = 0;
483 void *tmp;
484
485 #ifdef CONFIG_X86_32
486 if (boot_params.efi_info.efi_systab_hi ||
487 boot_params.efi_info.efi_memmap_hi) {
488 pr_info("Table located above 4GB, disabling EFI.\n");
489 return;
490 }
491 efi_phys.systab = (efi_system_table_t *)boot_params.efi_info.efi_systab;
492 #else
493 efi_phys.systab = (efi_system_table_t *)
494 (boot_params.efi_info.efi_systab |
495 ((__u64)boot_params.efi_info.efi_systab_hi<<32));
496 #endif
497
498 if (efi_systab_init(efi_phys.systab))
499 return;
500
501 efi.config_table = (unsigned long)efi.systab->tables;
502 efi.fw_vendor = (unsigned long)efi.systab->fw_vendor;
503 efi.runtime = (unsigned long)efi.systab->runtime;
504
505 /*
506 * Show what we know for posterity
507 */
508 c16 = tmp = early_memremap(efi.systab->fw_vendor, 2);
509 if (c16) {
510 for (i = 0; i < sizeof(vendor) - 1 && *c16; ++i)
511 vendor[i] = *c16++;
512 vendor[i] = '\0';
513 } else
514 pr_err("Could not map the firmware vendor!\n");
515 early_memunmap(tmp, 2);
516
517 pr_info("EFI v%u.%.02u by %s\n",
518 efi.systab->hdr.revision >> 16,
519 efi.systab->hdr.revision & 0xffff, vendor);
520
521 if (efi_reuse_config(efi.systab->tables, efi.systab->nr_tables))
522 return;
523
524 if (efi_config_init(arch_tables))
525 return;
526
527 /*
528 * Note: We currently don't support runtime services on an EFI
529 * that doesn't match the kernel 32/64-bit mode.
530 */
531
532 if (!efi_runtime_supported())
533 pr_info("No EFI runtime due to 32/64-bit mismatch with kernel\n");
534 else {
535 if (efi_runtime_disabled() || efi_runtime_init()) {
536 efi_memmap_unmap();
537 return;
538 }
539 }
540
541 efi_clean_memmap();
542
543 if (efi_enabled(EFI_DBG))
544 efi_print_memmap();
545 }
546
efi_set_executable(efi_memory_desc_t * md,bool executable)547 void __init efi_set_executable(efi_memory_desc_t *md, bool executable)
548 {
549 u64 addr, npages;
550
551 addr = md->virt_addr;
552 npages = md->num_pages;
553
554 memrange_efi_to_native(&addr, &npages);
555
556 if (executable)
557 set_memory_x(addr, npages);
558 else
559 set_memory_nx(addr, npages);
560 }
561
runtime_code_page_mkexec(void)562 void __init runtime_code_page_mkexec(void)
563 {
564 efi_memory_desc_t *md;
565
566 /* Make EFI runtime service code area executable */
567 for_each_efi_memory_desc(md) {
568 if (md->type != EFI_RUNTIME_SERVICES_CODE)
569 continue;
570
571 efi_set_executable(md, true);
572 }
573 }
574
efi_memory_uc(u64 addr,unsigned long size)575 void __init efi_memory_uc(u64 addr, unsigned long size)
576 {
577 unsigned long page_shift = 1UL << EFI_PAGE_SHIFT;
578 u64 npages;
579
580 npages = round_up(size, page_shift) / page_shift;
581 memrange_efi_to_native(&addr, &npages);
582 set_memory_uc(addr, npages);
583 }
584
old_map_region(efi_memory_desc_t * md)585 void __init old_map_region(efi_memory_desc_t *md)
586 {
587 u64 start_pfn, end_pfn, end;
588 unsigned long size;
589 void *va;
590
591 start_pfn = PFN_DOWN(md->phys_addr);
592 size = md->num_pages << PAGE_SHIFT;
593 end = md->phys_addr + size;
594 end_pfn = PFN_UP(end);
595
596 if (pfn_range_is_mapped(start_pfn, end_pfn)) {
597 va = __va(md->phys_addr);
598
599 if (!(md->attribute & EFI_MEMORY_WB))
600 efi_memory_uc((u64)(unsigned long)va, size);
601 } else
602 va = efi_ioremap(md->phys_addr, size,
603 md->type, md->attribute);
604
605 md->virt_addr = (u64) (unsigned long) va;
606 if (!va)
607 pr_err("ioremap of 0x%llX failed!\n",
608 (unsigned long long)md->phys_addr);
609 }
610
611 /* Merge contiguous regions of the same type and attribute */
efi_merge_regions(void)612 static void __init efi_merge_regions(void)
613 {
614 efi_memory_desc_t *md, *prev_md = NULL;
615
616 for_each_efi_memory_desc(md) {
617 u64 prev_size;
618
619 if (!prev_md) {
620 prev_md = md;
621 continue;
622 }
623
624 if (prev_md->type != md->type ||
625 prev_md->attribute != md->attribute) {
626 prev_md = md;
627 continue;
628 }
629
630 prev_size = prev_md->num_pages << EFI_PAGE_SHIFT;
631
632 if (md->phys_addr == (prev_md->phys_addr + prev_size)) {
633 prev_md->num_pages += md->num_pages;
634 md->type = EFI_RESERVED_TYPE;
635 md->attribute = 0;
636 continue;
637 }
638 prev_md = md;
639 }
640 }
641
get_systab_virt_addr(efi_memory_desc_t * md)642 static void __init get_systab_virt_addr(efi_memory_desc_t *md)
643 {
644 unsigned long size;
645 u64 end, systab;
646
647 size = md->num_pages << EFI_PAGE_SHIFT;
648 end = md->phys_addr + size;
649 systab = (u64)(unsigned long)efi_phys.systab;
650 if (md->phys_addr <= systab && systab < end) {
651 systab += md->virt_addr - md->phys_addr;
652 efi.systab = (efi_system_table_t *)(unsigned long)systab;
653 }
654 }
655
realloc_pages(void * old_memmap,int old_shift)656 static void *realloc_pages(void *old_memmap, int old_shift)
657 {
658 void *ret;
659
660 ret = (void *)__get_free_pages(GFP_KERNEL, old_shift + 1);
661 if (!ret)
662 goto out;
663
664 /*
665 * A first-time allocation doesn't have anything to copy.
666 */
667 if (!old_memmap)
668 return ret;
669
670 memcpy(ret, old_memmap, PAGE_SIZE << old_shift);
671
672 out:
673 free_pages((unsigned long)old_memmap, old_shift);
674 return ret;
675 }
676
677 /*
678 * Iterate the EFI memory map in reverse order because the regions
679 * will be mapped top-down. The end result is the same as if we had
680 * mapped things forward, but doesn't require us to change the
681 * existing implementation of efi_map_region().
682 */
efi_map_next_entry_reverse(void * entry)683 static inline void *efi_map_next_entry_reverse(void *entry)
684 {
685 /* Initial call */
686 if (!entry)
687 return efi.memmap.map_end - efi.memmap.desc_size;
688
689 entry -= efi.memmap.desc_size;
690 if (entry < efi.memmap.map)
691 return NULL;
692
693 return entry;
694 }
695
696 /*
697 * efi_map_next_entry - Return the next EFI memory map descriptor
698 * @entry: Previous EFI memory map descriptor
699 *
700 * This is a helper function to iterate over the EFI memory map, which
701 * we do in different orders depending on the current configuration.
702 *
703 * To begin traversing the memory map @entry must be %NULL.
704 *
705 * Returns %NULL when we reach the end of the memory map.
706 */
efi_map_next_entry(void * entry)707 static void *efi_map_next_entry(void *entry)
708 {
709 if (!efi_enabled(EFI_OLD_MEMMAP) && efi_enabled(EFI_64BIT)) {
710 /*
711 * Starting in UEFI v2.5 the EFI_PROPERTIES_TABLE
712 * config table feature requires us to map all entries
713 * in the same order as they appear in the EFI memory
714 * map. That is to say, entry N must have a lower
715 * virtual address than entry N+1. This is because the
716 * firmware toolchain leaves relative references in
717 * the code/data sections, which are split and become
718 * separate EFI memory regions. Mapping things
719 * out-of-order leads to the firmware accessing
720 * unmapped addresses.
721 *
722 * Since we need to map things this way whether or not
723 * the kernel actually makes use of
724 * EFI_PROPERTIES_TABLE, let's just switch to this
725 * scheme by default for 64-bit.
726 */
727 return efi_map_next_entry_reverse(entry);
728 }
729
730 /* Initial call */
731 if (!entry)
732 return efi.memmap.map;
733
734 entry += efi.memmap.desc_size;
735 if (entry >= efi.memmap.map_end)
736 return NULL;
737
738 return entry;
739 }
740
should_map_region(efi_memory_desc_t * md)741 static bool should_map_region(efi_memory_desc_t *md)
742 {
743 /*
744 * Runtime regions always require runtime mappings (obviously).
745 */
746 if (md->attribute & EFI_MEMORY_RUNTIME)
747 return true;
748
749 /*
750 * 32-bit EFI doesn't suffer from the bug that requires us to
751 * reserve boot services regions, and mixed mode support
752 * doesn't exist for 32-bit kernels.
753 */
754 if (IS_ENABLED(CONFIG_X86_32))
755 return false;
756
757 /*
758 * Map all of RAM so that we can access arguments in the 1:1
759 * mapping when making EFI runtime calls.
760 */
761 if (IS_ENABLED(CONFIG_EFI_MIXED) && !efi_is_native()) {
762 if (md->type == EFI_CONVENTIONAL_MEMORY ||
763 md->type == EFI_LOADER_DATA ||
764 md->type == EFI_LOADER_CODE)
765 return true;
766 }
767
768 /*
769 * Map boot services regions as a workaround for buggy
770 * firmware that accesses them even when they shouldn't.
771 *
772 * See efi_{reserve,free}_boot_services().
773 */
774 if (md->type == EFI_BOOT_SERVICES_CODE ||
775 md->type == EFI_BOOT_SERVICES_DATA)
776 return true;
777
778 return false;
779 }
780
781 /*
782 * Map the efi memory ranges of the runtime services and update new_mmap with
783 * virtual addresses.
784 */
efi_map_regions(int * count,int * pg_shift)785 static void * __init efi_map_regions(int *count, int *pg_shift)
786 {
787 void *p, *new_memmap = NULL;
788 unsigned long left = 0;
789 unsigned long desc_size;
790 efi_memory_desc_t *md;
791
792 desc_size = efi.memmap.desc_size;
793
794 p = NULL;
795 while ((p = efi_map_next_entry(p))) {
796 md = p;
797
798 if (!should_map_region(md))
799 continue;
800
801 efi_map_region(md);
802 get_systab_virt_addr(md);
803
804 if (left < desc_size) {
805 new_memmap = realloc_pages(new_memmap, *pg_shift);
806 if (!new_memmap)
807 return NULL;
808
809 left += PAGE_SIZE << *pg_shift;
810 (*pg_shift)++;
811 }
812
813 memcpy(new_memmap + (*count * desc_size), md, desc_size);
814
815 left -= desc_size;
816 (*count)++;
817 }
818
819 return new_memmap;
820 }
821
kexec_enter_virtual_mode(void)822 static void __init kexec_enter_virtual_mode(void)
823 {
824 #ifdef CONFIG_KEXEC_CORE
825 efi_memory_desc_t *md;
826 unsigned int num_pages;
827
828 efi.systab = NULL;
829
830 /*
831 * We don't do virtual mode, since we don't do runtime services, on
832 * non-native EFI. With efi=old_map, we don't do runtime services in
833 * kexec kernel because in the initial boot something else might
834 * have been mapped at these virtual addresses.
835 */
836 if (!efi_is_native() || efi_enabled(EFI_OLD_MEMMAP)) {
837 efi_memmap_unmap();
838 clear_bit(EFI_RUNTIME_SERVICES, &efi.flags);
839 return;
840 }
841
842 if (efi_alloc_page_tables()) {
843 pr_err("Failed to allocate EFI page tables\n");
844 clear_bit(EFI_RUNTIME_SERVICES, &efi.flags);
845 return;
846 }
847
848 /*
849 * Map efi regions which were passed via setup_data. The virt_addr is a
850 * fixed addr which was used in first kernel of a kexec boot.
851 */
852 for_each_efi_memory_desc(md) {
853 efi_map_region_fixed(md); /* FIXME: add error handling */
854 get_systab_virt_addr(md);
855 }
856
857 /*
858 * Unregister the early EFI memmap from efi_init() and install
859 * the new EFI memory map.
860 */
861 efi_memmap_unmap();
862
863 if (efi_memmap_init_late(efi.memmap.phys_map,
864 efi.memmap.desc_size * efi.memmap.nr_map)) {
865 pr_err("Failed to remap late EFI memory map\n");
866 clear_bit(EFI_RUNTIME_SERVICES, &efi.flags);
867 return;
868 }
869
870 BUG_ON(!efi.systab);
871
872 num_pages = ALIGN(efi.memmap.nr_map * efi.memmap.desc_size, PAGE_SIZE);
873 num_pages >>= PAGE_SHIFT;
874
875 if (efi_setup_page_tables(efi.memmap.phys_map, num_pages)) {
876 clear_bit(EFI_RUNTIME_SERVICES, &efi.flags);
877 return;
878 }
879
880 efi_sync_low_kernel_mappings();
881
882 /*
883 * Now that EFI is in virtual mode, update the function
884 * pointers in the runtime service table to the new virtual addresses.
885 *
886 * Call EFI services through wrapper functions.
887 */
888 efi.runtime_version = efi_systab.hdr.revision;
889
890 efi_native_runtime_setup();
891
892 efi.set_virtual_address_map = NULL;
893
894 if (efi_enabled(EFI_OLD_MEMMAP) && (__supported_pte_mask & _PAGE_NX))
895 runtime_code_page_mkexec();
896
897 /* clean DUMMY object */
898 efi_delete_dummy_variable();
899 #endif
900 }
901
902 /*
903 * This function will switch the EFI runtime services to virtual mode.
904 * Essentially, we look through the EFI memmap and map every region that
905 * has the runtime attribute bit set in its memory descriptor into the
906 * efi_pgd page table.
907 *
908 * The old method which used to update that memory descriptor with the
909 * virtual address obtained from ioremap() is still supported when the
910 * kernel is booted with efi=old_map on its command line. Same old
911 * method enabled the runtime services to be called without having to
912 * thunk back into physical mode for every invocation.
913 *
914 * The new method does a pagetable switch in a preemption-safe manner
915 * so that we're in a different address space when calling a runtime
916 * function. For function arguments passing we do copy the PUDs of the
917 * kernel page table into efi_pgd prior to each call.
918 *
919 * Specially for kexec boot, efi runtime maps in previous kernel should
920 * be passed in via setup_data. In that case runtime ranges will be mapped
921 * to the same virtual addresses as the first kernel, see
922 * kexec_enter_virtual_mode().
923 */
__efi_enter_virtual_mode(void)924 static void __init __efi_enter_virtual_mode(void)
925 {
926 int count = 0, pg_shift = 0;
927 void *new_memmap = NULL;
928 efi_status_t status;
929 unsigned long pa;
930
931 efi.systab = NULL;
932
933 if (efi_alloc_page_tables()) {
934 pr_err("Failed to allocate EFI page tables\n");
935 clear_bit(EFI_RUNTIME_SERVICES, &efi.flags);
936 return;
937 }
938
939 efi_merge_regions();
940 new_memmap = efi_map_regions(&count, &pg_shift);
941 if (!new_memmap) {
942 pr_err("Error reallocating memory, EFI runtime non-functional!\n");
943 clear_bit(EFI_RUNTIME_SERVICES, &efi.flags);
944 return;
945 }
946
947 pa = __pa(new_memmap);
948
949 /*
950 * Unregister the early EFI memmap from efi_init() and install
951 * the new EFI memory map that we are about to pass to the
952 * firmware via SetVirtualAddressMap().
953 */
954 efi_memmap_unmap();
955
956 if (efi_memmap_init_late(pa, efi.memmap.desc_size * count)) {
957 pr_err("Failed to remap late EFI memory map\n");
958 clear_bit(EFI_RUNTIME_SERVICES, &efi.flags);
959 return;
960 }
961
962 if (efi_enabled(EFI_DBG)) {
963 pr_info("EFI runtime memory map:\n");
964 efi_print_memmap();
965 }
966
967 BUG_ON(!efi.systab);
968
969 if (efi_setup_page_tables(pa, 1 << pg_shift)) {
970 clear_bit(EFI_RUNTIME_SERVICES, &efi.flags);
971 return;
972 }
973
974 efi_sync_low_kernel_mappings();
975
976 if (efi_is_native()) {
977 status = phys_efi_set_virtual_address_map(
978 efi.memmap.desc_size * count,
979 efi.memmap.desc_size,
980 efi.memmap.desc_version,
981 (efi_memory_desc_t *)pa);
982 } else {
983 status = efi_thunk_set_virtual_address_map(
984 efi_phys.set_virtual_address_map,
985 efi.memmap.desc_size * count,
986 efi.memmap.desc_size,
987 efi.memmap.desc_version,
988 (efi_memory_desc_t *)pa);
989 }
990
991 if (status != EFI_SUCCESS) {
992 pr_alert("Unable to switch EFI into virtual mode (status=%lx)!\n",
993 status);
994 panic("EFI call to SetVirtualAddressMap() failed!");
995 }
996
997 /*
998 * Now that EFI is in virtual mode, update the function
999 * pointers in the runtime service table to the new virtual addresses.
1000 *
1001 * Call EFI services through wrapper functions.
1002 */
1003 efi.runtime_version = efi_systab.hdr.revision;
1004
1005 if (efi_is_native())
1006 efi_native_runtime_setup();
1007 else
1008 efi_thunk_runtime_setup();
1009
1010 efi.set_virtual_address_map = NULL;
1011
1012 /*
1013 * Apply more restrictive page table mapping attributes now that
1014 * SVAM() has been called and the firmware has performed all
1015 * necessary relocation fixups for the new virtual addresses.
1016 */
1017 efi_runtime_update_mappings();
1018
1019 /* clean DUMMY object */
1020 efi_delete_dummy_variable();
1021 }
1022
efi_enter_virtual_mode(void)1023 void __init efi_enter_virtual_mode(void)
1024 {
1025 if (efi_enabled(EFI_PARAVIRT))
1026 return;
1027
1028 if (efi_setup)
1029 kexec_enter_virtual_mode();
1030 else
1031 __efi_enter_virtual_mode();
1032
1033 efi_dump_pagetable();
1034 }
1035
arch_parse_efi_cmdline(char * str)1036 static int __init arch_parse_efi_cmdline(char *str)
1037 {
1038 if (!str) {
1039 pr_warn("need at least one option\n");
1040 return -EINVAL;
1041 }
1042
1043 if (parse_option_str(str, "old_map"))
1044 set_bit(EFI_OLD_MEMMAP, &efi.flags);
1045
1046 return 0;
1047 }
1048 early_param("efi", arch_parse_efi_cmdline);
1049
