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 #include <linux/pgtable.h>
  22
  23 #include <asm/cacheflush.h>
  24 #include <asm/efi.h>
  25 #include <asm/mmu.h>
  26 #include <asm/pgalloc.h>
  27
  28 #if defined(CONFIG_PTDUMP_DEBUGFS) && defined(CONFIG_ARM64)
  29 #include <asm/ptdump.h>
  30
  31 static struct ptdump_info efi_ptdump_info = {
  32         .mm             = &efi_mm,
  33         .markers        = (struct addr_marker[]){
  34                 { 0,                            "UEFI runtime start" },
  35                 { DEFAULT_MAP_WINDOW_64,        "UEFI runtime end" },
  36                 { -1,                           NULL }
  37         },
  38         .base_addr      = 0,
  39 };
  40
  41 static int __init ptdump_init(void)
  42 {
  43         if (efi_enabled(EFI_RUNTIME_SERVICES))
  44                 ptdump_debugfs_register(&efi_ptdump_info, "efi_page_tables");
  45
  46         return 0;
  47 }
  48 device_initcall(ptdump_init);
  49
  50 #endif
  51
  52 static bool __init efi_virtmap_init(void)
  53 {
  54         efi_memory_desc_t *md;
  55
  56         efi_mm.pgd = pgd_alloc(&efi_mm);
  57         mm_init_cpumask(&efi_mm);
  58         init_new_context(NULL, &efi_mm);
  59
  60         for_each_efi_memory_desc(md) {
  61                 phys_addr_t phys = md->phys_addr;
  62                 int ret;
  63
  64                 if (!(md->attribute & EFI_MEMORY_RUNTIME))
  65                         continue;
  66                 if (md->virt_addr == 0)
  67                         return false;
  68
  69                 ret = efi_create_mapping(&efi_mm, md);
  70                 if (ret) {
  71                         pr_warn("  EFI remap %pa: failed to create mapping (%d)\n",
  72                                 &phys, ret);
  73                         return false;
  74                 }
  75         }
  76
  77         if (efi_memattr_apply_permissions(&efi_mm, efi_set_mapping_permissions))
  78                 return false;
  79
  80         return true;
  81 }
  82
  83 /*
  84  * Enable the UEFI Runtime Services if all prerequisites are in place, i.e.,
  85  * non-early mapping of the UEFI system table and virtual mappings for all
  86  * EFI_MEMORY_RUNTIME regions.
  87  */
  88 static int __init arm_enable_runtime_services(void)
  89 {
  90         u64 mapsize;
  91
  92         if (!efi_enabled(EFI_BOOT)) {
  93                 pr_info("EFI services will not be available.\n");
  94                 return 0;
  95         }
  96
  97         efi_memmap_unmap();
  98
  99         mapsize = efi.memmap.desc_size * efi.memmap.nr_map;
 100
 101         if (efi_memmap_init_late(efi.memmap.phys_map, mapsize)) {
 102                 pr_err("Failed to remap EFI memory map\n");
 103                 return 0;
 104         }
 105
 106         if (efi_soft_reserve_enabled()) {
 107                 efi_memory_desc_t *md;
 108
 109                 for_each_efi_memory_desc(md) {
 110                         int md_size = md->num_pages << EFI_PAGE_SHIFT;
 111                         struct resource *res;
 112
 113                         if (!(md->attribute & EFI_MEMORY_SP))
 114                                 continue;
 115
 116                         res = kzalloc(sizeof(*res), GFP_KERNEL);
 117                         if (WARN_ON(!res))
 118                                 break;
 119
 120                         res->start      = md->phys_addr;
 121                         res->end        = md->phys_addr + md_size - 1;
 122                         res->name       = "Soft Reserved";
 123                         res->flags      = IORESOURCE_MEM;
 124                         res->desc       = IORES_DESC_SOFT_RESERVED;
 125
 126                         insert_resource(&iomem_resource, res);
 127                 }
 128         }
 129
 130         if (efi_runtime_disabled()) {
 131                 pr_info("EFI runtime services will be disabled.\n");
 132                 return 0;
 133         }
 134
 135         if (efi_enabled(EFI_RUNTIME_SERVICES)) {
 136                 pr_info("EFI runtime services access via paravirt.\n");
 137                 return 0;
 138         }
 139
 140         pr_info("Remapping and enabling EFI services.\n");
 141
 142         if (!efi_virtmap_init()) {
 143                 pr_err("UEFI virtual mapping missing or invalid -- runtime services will not be available\n");
 144                 return -ENOMEM;
 145         }
 146
 147         /* Set up runtime services function pointers */
 148         efi_native_runtime_setup();
 149         set_bit(EFI_RUNTIME_SERVICES, &efi.flags);
 150
 151         return 0;
 152 }
 153 early_initcall(arm_enable_runtime_services);
 154
 155 void efi_virtmap_load(void)
 156 {
 157         preempt_disable();
 158         efi_set_pgd(&efi_mm);
 159 }
 160
 161 void efi_virtmap_unload(void)
 162 {
 163         efi_set_pgd(current->active_mm);
 164         preempt_enable();
 165 }
 166
 167
 168 static int __init arm_dmi_init(void)
 169 {
 170         /*
 171          * On arm64/ARM, DMI depends on UEFI, and dmi_setup() needs to
 172          * be called early because dmi_id_init(), which is an arch_initcall
 173          * itself, depends on dmi_scan_machine() having been called already.
 174          */
 175         dmi_setup();
 176         return 0;
 177 }
 178 core_initcall(arm_dmi_init);