drivers/firmware/efi/arm-runtime.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Extensible Firmware Interface
   4  *
   5  * Based on Extensible Firmware Interface Specification version 2.4
   6  *
   7  * Copyright (C) 2013, 2014 Linaro Ltd.
   8  */
   9
  10 #include <linux/dmi.h>
  11 #include <linux/efi.h>
  12 #include <linux/io.h>
  13 #include <linux/memblock.h>
  14 #include <linux/mm_types.h>
  15 #include <linux/preempt.h>
  16 #include <linux/rbtree.h>
  17 #include <linux/rwsem.h>
  18 #include <linux/sched.h>
  19 #include <linux/slab.h>
  20 #include <linux/spinlock.h>
  21
  22 #include <asm/cacheflush.h>
  23 #include <asm/efi.h>
  24 #include <asm/mmu.h>
  25 #include <asm/pgalloc.h>
  26 #include <asm/pgtable.h>
  27
  28 extern u64 efi_system_table;
  29
  30 #if defined(CONFIG_PTDUMP_DEBUGFS) && defined(CONFIG_ARM64)
  31 #include <asm/ptdump.h>
  32
  33 static struct ptdump_info efi_ptdump_info = {
  34         .mm             = &efi_mm,
  35         .markers        = (struct addr_marker[]){
  36                 { 0,                            "UEFI runtime start" },
  37                 { DEFAULT_MAP_WINDOW_64,        "UEFI runtime end" },
  38                 { -1,                           NULL }
  39         },
  40         .base_addr      = 0,
  41 };
  42
  43 static int __init ptdump_init(void)
  44 {
  45         if (efi_enabled(EFI_RUNTIME_SERVICES))
  46                 ptdump_debugfs_register(&efi_ptdump_info, "efi_page_tables");
  47
  48         return 0;
  49 }
  50 device_initcall(ptdump_init);
  51
  52 #endif
  53
  54 static bool __init efi_virtmap_init(void)
  55 {
  56         efi_memory_desc_t *md;
  57         bool systab_found;
  58
  59         efi_mm.pgd = pgd_alloc(&efi_mm);
  60         mm_init_cpumask(&efi_mm);
  61         init_new_context(NULL, &efi_mm);
  62
  63         systab_found = false;
  64         for_each_efi_memory_desc(md) {
  65                 phys_addr_t phys = md->phys_addr;
  66                 int ret;
  67
  68                 if (!(md->attribute & EFI_MEMORY_RUNTIME))
  69                         continue;
  70                 if (md->virt_addr == 0)
  71                         return false;
  72
  73                 ret = efi_create_mapping(&efi_mm, md);
  74                 if (ret) {
  75                         pr_warn("  EFI remap %pa: failed to create mapping (%d)\n",
  76                                 &phys, ret);
  77                         return false;
  78                 }
  79                 /*
  80                  * If this entry covers the address of the UEFI system table,
  81                  * calculate and record its virtual address.
  82                  */
  83                 if (efi_system_table >= phys &&
  84                     efi_system_table < phys + (md->num_pages * EFI_PAGE_SIZE)) {
  85                         efi.systab = (void *)(unsigned long)(efi_system_table -
  86                                                              phys + md->virt_addr);
  87                         systab_found = true;
  88                 }
  89         }
  90         if (!systab_found) {
  91                 pr_err("No virtual mapping found for the UEFI System Table\n");
  92                 return false;
  93         }
  94
  95         if (efi_memattr_apply_permissions(&efi_mm, efi_set_mapping_permissions))
  96                 return false;
  97
  98         return true;
  99 }
 100
 101 /*
 102  * Enable the UEFI Runtime Services if all prerequisites are in place, i.e.,
 103  * non-early mapping of the UEFI system table and virtual mappings for all
 104  * EFI_MEMORY_RUNTIME regions.
 105  */
 106 static int __init arm_enable_runtime_services(void)
 107 {
 108         u64 mapsize;
 109
 110         if (!efi_enabled(EFI_BOOT)) {
 111                 pr_info("EFI services will not be available.\n");
 112                 return 0;
 113         }
 114
 115         efi_memmap_unmap();
 116
 117         mapsize = efi.memmap.desc_size * efi.memmap.nr_map;
 118
 119         if (efi_memmap_init_late(efi.memmap.phys_map, mapsize)) {
 120                 pr_err("Failed to remap EFI memory map\n");
 121                 return 0;
 122         }
 123
 124         if (efi_soft_reserve_enabled()) {
 125                 efi_memory_desc_t *md;
 126
 127                 for_each_efi_memory_desc(md) {
 128                         int md_size = md->num_pages << EFI_PAGE_SHIFT;
 129                         struct resource *res;
 130
 131                         if (!(md->attribute & EFI_MEMORY_SP))
 132                                 continue;
 133
 134                         res = kzalloc(sizeof(*res), GFP_KERNEL);
 135                         if (WARN_ON(!res))
 136                                 break;
 137
 138                         res->start      = md->phys_addr;
 139                         res->end        = md->phys_addr + md_size - 1;
 140                         res->name       = "Soft Reserved";
 141                         res->flags      = IORESOURCE_MEM;
 142                         res->desc       = IORES_DESC_SOFT_RESERVED;
 143
 144                         insert_resource(&iomem_resource, res);
 145                 }
 146         }
 147
 148         if (efi_runtime_disabled()) {
 149                 pr_info("EFI runtime services will be disabled.\n");
 150                 return 0;
 151         }
 152
 153         if (efi_enabled(EFI_RUNTIME_SERVICES)) {
 154                 pr_info("EFI runtime services access via paravirt.\n");
 155                 return 0;
 156         }
 157
 158         pr_info("Remapping and enabling EFI services.\n");
 159
 160         if (!efi_virtmap_init()) {
 161                 pr_err("UEFI virtual mapping missing or invalid -- runtime services will not be available\n");
 162                 return -ENOMEM;
 163         }
 164
 165         /* Set up runtime services function pointers */
 166         efi_native_runtime_setup();
 167         set_bit(EFI_RUNTIME_SERVICES, &efi.flags);
 168
 169         return 0;
 170 }
 171 early_initcall(arm_enable_runtime_services);
 172
 173 void efi_virtmap_load(void)
 174 {
 175         preempt_disable();
 176         efi_set_pgd(&efi_mm);
 177 }
 178
 179 void efi_virtmap_unload(void)
 180 {
 181         efi_set_pgd(current->active_mm);
 182         preempt_enable();
 183 }
 184
 185
 186 static int __init arm_dmi_init(void)
 187 {
 188         /*
 189          * On arm64/ARM, DMI depends on UEFI, and dmi_setup() needs to
 190          * be called early because dmi_id_init(), which is an arch_initcall
 191          * itself, depends on dmi_scan_machine() having been called already.
 192          */
 193         dmi_setup();
 194         return 0;
 195 }
 196 core_initcall(arm_dmi_init);