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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Extensible Firmware Interface
4 *
5 * Copyright (C) 2020 Western Digital Corporation or its affiliates.
6 *
7 * Based on Extensible Firmware Interface Specification version 2.4
8 * Adapted from drivers/firmware/efi/arm-runtime.c
9 *
10 */
11
12#include <linux/dmi.h>
13#include <linux/efi.h>
14#include <linux/io.h>
15#include <linux/memblock.h>
16#include <linux/mm_types.h>
17#include <linux/pgalloc.h>
18#include <linux/pgtable.h>
19#include <linux/preempt.h>
20#include <linux/rbtree.h>
21#include <linux/rwsem.h>
22#include <linux/sched.h>
23#include <linux/slab.h>
24#include <linux/spinlock.h>
25
26#include <asm/cacheflush.h>
27#include <asm/efi.h>
28#include <asm/mmu.h>
29
30static bool __init efi_virtmap_init(void)
31{
32 efi_memory_desc_t *md;
33
34 efi_mm.pgd = pgd_alloc(&efi_mm);
35 mm_init_cpumask(&efi_mm);
36 init_new_context(NULL, &efi_mm);
37
38 for_each_efi_memory_desc(md) {
39 if (!(md->attribute & EFI_MEMORY_RUNTIME))
40 continue;
41 if (md->virt_addr == U64_MAX)
42 return false;
43
44 efi_create_mapping(&efi_mm, md);
45 }
46
47 if (efi_memattr_apply_permissions(&efi_mm, efi_set_mapping_permissions))
48 return false;
49
50 return true;
51}
52
53/*
54 * Enable the UEFI Runtime Services if all prerequisites are in place, i.e.,
55 * non-early mapping of the UEFI system table and virtual mappings for all
56 * EFI_MEMORY_RUNTIME regions.
57 */
58static int __init riscv_enable_runtime_services(void)
59{
60 u64 mapsize;
61
62 if (!efi_enabled(EFI_BOOT)) {
63 pr_info("EFI services will not be available.\n");
64 return 0;
65 }
66
67 efi_memmap_unmap();
68
69 mapsize = efi.memmap.desc_size * efi.memmap.nr_map;
70
71 if (efi_memmap_init_late(efi.memmap.phys_map, mapsize)) {
72 pr_err("Failed to remap EFI memory map\n");
73 return 0;
74 }
75
76 if (efi_soft_reserve_enabled()) {
77 efi_memory_desc_t *md;
78
79 for_each_efi_memory_desc(md) {
80 u64 md_size = md->num_pages << EFI_PAGE_SHIFT;
81 struct resource *res;
82
83 if (!(md->attribute & EFI_MEMORY_SP))
84 continue;
85
86 res = kzalloc_obj(*res);
87 if (WARN_ON(!res))
88 break;
89
90 res->start = md->phys_addr;
91 res->end = md->phys_addr + md_size - 1;
92 res->name = "Soft Reserved";
93 res->flags = IORESOURCE_MEM;
94 res->desc = IORES_DESC_SOFT_RESERVED;
95
96 insert_resource(&iomem_resource, res);
97 }
98 }
99
100 if (efi_runtime_disabled()) {
101 pr_info("EFI runtime services will be disabled.\n");
102 return 0;
103 }
104
105 if (efi_enabled(EFI_RUNTIME_SERVICES)) {
106 pr_info("EFI runtime services access via paravirt.\n");
107 return 0;
108 }
109
110 pr_info("Remapping and enabling EFI services.\n");
111
112 if (!efi_virtmap_init()) {
113 pr_err("UEFI virtual mapping missing or invalid -- runtime services will not be available\n");
114 return -ENOMEM;
115 }
116
117 /* Set up runtime services function pointers */
118 efi_native_runtime_setup();
119 set_bit(EFI_RUNTIME_SERVICES, &efi.flags);
120
121 return 0;
122}
123early_initcall(riscv_enable_runtime_services);
124
125static void efi_virtmap_load(void)
126{
127 preempt_disable();
128 switch_mm(current->active_mm, &efi_mm, NULL);
129}
130
131static void efi_virtmap_unload(void)
132{
133 switch_mm(&efi_mm, current->active_mm, NULL);
134 preempt_enable();
135}
136
137void arch_efi_call_virt_setup(void)
138{
139 sync_kernel_mappings(efi_mm.pgd);
140 efi_virtmap_load();
141}
142
143void arch_efi_call_virt_teardown(void)
144{
145 efi_virtmap_unload();
146}
147
148static int __init riscv_dmi_init(void)
149{
150 /*
151 * On riscv, DMI depends on UEFI, and dmi_setup() needs to
152 * be called early because dmi_id_init(), which is an arch_initcall
153 * itself, depends on dmi_scan_machine() having been called already.
154 */
155 dmi_setup();
156
157 return 0;
158}
159core_initcall(riscv_dmi_init);