aboutsummaryrefslogtreecommitdiff
path: root/arch/arm64/kernel/efi.c
blob: 61eb1d17586a859a1fcc1d0d0fd653028d736b11 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
/*
 * Extensible Firmware Interface
 *
 * Based on Extensible Firmware Interface Specification version 2.4
 *
 * Copyright (C) 2013, 2014 Linaro Ltd.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 */

#include <linux/atomic.h>
#include <linux/dmi.h>
#include <linux/efi.h>
#include <linux/export.h>
#include <linux/memblock.h>
#include <linux/mm_types.h>
#include <linux/bootmem.h>
#include <linux/of.h>
#include <linux/of_fdt.h>
#include <linux/preempt.h>
#include <linux/rbtree.h>
#include <linux/rwsem.h>
#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/spinlock.h>

#include <asm/cacheflush.h>
#include <asm/efi.h>
#include <asm/tlbflush.h>
#include <asm/mmu_context.h>
#include <asm/mmu.h>
#include <asm/pgtable.h>

struct efi_memory_map memmap;

static u64 efi_system_table;

static pgd_t efi_pgd[PTRS_PER_PGD] __page_aligned_bss;

static struct mm_struct efi_mm = {
	.mm_rb			= RB_ROOT,
	.pgd			= efi_pgd,
	.mm_users		= ATOMIC_INIT(2),
	.mm_count		= ATOMIC_INIT(1),
	.mmap_sem		= __RWSEM_INITIALIZER(efi_mm.mmap_sem),
	.page_table_lock	= __SPIN_LOCK_UNLOCKED(efi_mm.page_table_lock),
	.mmlist			= LIST_HEAD_INIT(efi_mm.mmlist),
	INIT_MM_CONTEXT(efi_mm)
};

static int __init is_normal_ram(efi_memory_desc_t *md)
{
	if (md->attribute & EFI_MEMORY_WB)
		return 1;
	return 0;
}

/*
 * Translate a EFI virtual address into a physical address: this is necessary,
 * as some data members of the EFI system table are virtually remapped after
 * SetVirtualAddressMap() has been called.
 */
static phys_addr_t efi_to_phys(unsigned long addr)
{
	efi_memory_desc_t *md;

	for_each_efi_memory_desc(&memmap, md) {
		if (!(md->attribute & EFI_MEMORY_RUNTIME))
			continue;
		if (md->virt_addr == 0)
			/* no virtual mapping has been installed by the stub */
			break;
		if (md->virt_addr <= addr &&
		    (addr - md->virt_addr) < (md->num_pages << EFI_PAGE_SHIFT))
			return md->phys_addr + addr - md->virt_addr;
	}
	return addr;
}

static int __init uefi_init(void)
{
	efi_char16_t *c16;
	void *config_tables;
	u64 table_size;
	char vendor[100] = "unknown";
	int i, retval;

	efi.systab = early_memremap(efi_system_table,
				    sizeof(efi_system_table_t));
	if (efi.systab == NULL) {
		pr_warn("Unable to map EFI system table.\n");
		return -ENOMEM;
	}

	set_bit(EFI_BOOT, &efi.flags);
	set_bit(EFI_64BIT, &efi.flags);

	/*
	 * Verify the EFI Table
	 */
	if (efi.systab->hdr.signature != EFI_SYSTEM_TABLE_SIGNATURE) {
		pr_err("System table signature incorrect\n");
		retval = -EINVAL;
		goto out;
	}
	if ((efi.systab->hdr.revision >> 16) < 2)
		pr_warn("Warning: EFI system table version %d.%02d, expected 2.00 or greater\n",
			efi.systab->hdr.revision >> 16,
			efi.systab->hdr.revision & 0xffff);

	/* Show what we know for posterity */
	c16 = early_memremap(efi_to_phys(efi.systab->fw_vendor),
			     sizeof(vendor) * sizeof(efi_char16_t));
	if (c16) {
		for (i = 0; i < (int) sizeof(vendor) - 1 && *c16; ++i)
			vendor[i] = c16[i];
		vendor[i] = '\0';
		early_memunmap(c16, sizeof(vendor) * sizeof(efi_char16_t));
	}

	pr_info("EFI v%u.%.02u by %s\n",
		efi.systab->hdr.revision >> 16,
		efi.systab->hdr.revision & 0xffff, vendor);

	table_size = sizeof(efi_config_table_64_t) * efi.systab->nr_tables;
	config_tables = early_memremap(efi_to_phys(efi.systab->tables),
				       table_size);

	retval = efi_config_parse_tables(config_tables, efi.systab->nr_tables,
					 sizeof(efi_config_table_64_t), NULL);

	early_memunmap(config_tables, table_size);
out:
	early_memunmap(efi.systab,  sizeof(efi_system_table_t));
	return retval;
}

/*
 * Return true for RAM regions we want to permanently reserve.
 */
static __init int is_reserve_region(efi_memory_desc_t *md)
{
	switch (md->type) {
	case EFI_LOADER_CODE:
	case EFI_LOADER_DATA:
	case EFI_BOOT_SERVICES_CODE:
	case EFI_BOOT_SERVICES_DATA:
	case EFI_CONVENTIONAL_MEMORY:
	case EFI_PERSISTENT_MEMORY:
		return 0;
	default:
		break;
	}
	return is_normal_ram(md);
}

static __init void reserve_regions(void)
{
	efi_memory_desc_t *md;
	u64 paddr, npages, size;

	if (efi_enabled(EFI_DBG))
		pr_info("Processing EFI memory map:\n");

	for_each_efi_memory_desc(&memmap, md) {
		paddr = md->phys_addr;
		npages = md->num_pages;

		if (efi_enabled(EFI_DBG)) {
			char buf[64];

			pr_info("  0x%012llx-0x%012llx %s",
				paddr, paddr + (npages << EFI_PAGE_SHIFT) - 1,
				efi_md_typeattr_format(buf, sizeof(buf), md));
		}

		memrange_efi_to_native(&paddr, &npages);
		size = npages << PAGE_SHIFT;

		if (is_normal_ram(md))
			early_init_dt_add_memory_arch(paddr, size);

		if (is_reserve_region(md)) {
			memblock_reserve(paddr, size);
			if (efi_enabled(EFI_DBG))
				pr_cont("*");
		}

		if (efi_enabled(EFI_DBG))
			pr_cont("\n");
	}

	set_bit(EFI_MEMMAP, &efi.flags);
}

void __init efi_init(void)
{
	struct efi_fdt_params params;

	/* Grab UEFI information placed in FDT by stub */
	if (!efi_get_fdt_params(&params))
		return;

	efi_system_table = params.system_table;

	memblock_reserve(params.mmap & PAGE_MASK,
			 PAGE_ALIGN(params.mmap_size + (params.mmap & ~PAGE_MASK)));
	memmap.phys_map = params.mmap;
	memmap.map = early_memremap(params.mmap, params.mmap_size);
	memmap.map_end = memmap.map + params.mmap_size;
	memmap.desc_size = params.desc_size;
	memmap.desc_version = params.desc_ver;

	if (uefi_init() < 0)
		return;

	reserve_regions();
	early_memunmap(memmap.map, params.mmap_size);
}

static bool __init efi_virtmap_init(void)
{
	efi_memory_desc_t *md;

	for_each_efi_memory_desc(&memmap, md) {
		u64 paddr, npages, size;
		pgprot_t prot;

		if (!(md->attribute & EFI_MEMORY_RUNTIME))
			continue;
		if (md->virt_addr == 0)
			return false;

		paddr = md->phys_addr;
		npages = md->num_pages;
		memrange_efi_to_native(&paddr, &npages);
		size = npages << PAGE_SHIFT;

		pr_info("  EFI remap 0x%016llx => %p\n",
			md->phys_addr, (void *)md->virt_addr);

		/*
		 * Only regions of type EFI_RUNTIME_SERVICES_CODE need to be
		 * executable, everything else can be mapped with the XN bits
		 * set.
		 */
		if (!is_normal_ram(md))
			prot = __pgprot(PROT_DEVICE_nGnRE);
		else if (md->type == EFI_RUNTIME_SERVICES_CODE ||
			 !PAGE_ALIGNED(md->phys_addr))
			prot = PAGE_KERNEL_EXEC;
		else
			prot = PAGE_KERNEL;

		create_pgd_mapping(&efi_mm, paddr, md->virt_addr, size, prot);
	}
	return true;
}

/*
 * Enable the UEFI Runtime Services if all prerequisites are in place, i.e.,
 * non-early mapping of the UEFI system table and virtual mappings for all
 * EFI_MEMORY_RUNTIME regions.
 */
static int __init arm64_enable_runtime_services(void)
{
	u64 mapsize;

	if (!efi_enabled(EFI_BOOT)) {
		pr_info("EFI services will not be available.\n");
		return -1;
	}

	if (efi_runtime_disabled()) {
		pr_info("EFI runtime services will be disabled.\n");
		return -1;
	}

	pr_info("Remapping and enabling EFI services.\n");

	mapsize = memmap.map_end - memmap.map;
	memmap.map = (__force void *)ioremap_cache(memmap.phys_map,
						   mapsize);
	if (!memmap.map) {
		pr_err("Failed to remap EFI memory map\n");
		return -1;
	}
	memmap.map_end = memmap.map + mapsize;
	efi.memmap = &memmap;

	efi.systab = (__force void *)ioremap_cache(efi_system_table,
						   sizeof(efi_system_table_t));
	if (!efi.systab) {
		pr_err("Failed to remap EFI System Table\n");
		return -1;
	}
	set_bit(EFI_SYSTEM_TABLES, &efi.flags);

	if (!efi_virtmap_init()) {
		pr_err("No UEFI virtual mapping was installed -- runtime services will not be available\n");
		return -1;
	}

	/* Set up runtime services function pointers */
	efi_native_runtime_setup();
	set_bit(EFI_RUNTIME_SERVICES, &efi.flags);

	efi.runtime_version = efi.systab->hdr.revision;

	return 0;
}
early_initcall(arm64_enable_runtime_services);

static int __init arm64_dmi_init(void)
{
	/*
	 * On arm64, DMI depends on UEFI, and dmi_scan_machine() needs to
	 * be called early because dmi_id_init(), which is an arch_initcall
	 * itself, depends on dmi_scan_machine() having been called already.
	 */
	dmi_scan_machine();
	if (dmi_available)
		dmi_set_dump_stack_arch_desc();
	return 0;
}
core_initcall(arm64_dmi_init);

static void efi_set_pgd(struct mm_struct *mm)
{
	if (mm == &init_mm)
		cpu_set_reserved_ttbr0();
	else
		cpu_switch_mm(mm->pgd, mm);

	flush_tlb_all();
	if (icache_is_aivivt())
		__flush_icache_all();
}

void efi_virtmap_load(void)
{
	preempt_disable();
	efi_set_pgd(&efi_mm);
}

void efi_virtmap_unload(void)
{
	efi_set_pgd(current->active_mm);
	preempt_enable();
}

/*
 * UpdateCapsule() depends on the system being shutdown via
 * ResetSystem().
 */
bool efi_poweroff_required(void)
{
	return efi_enabled(EFI_RUNTIME_SERVICES);
}