LXR linux/drivers/firmware/efi/efi-init.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 - 2015 Linaro Ltd.
   8 */
   9
  10#define pr_fmt(fmt)     "efi: " fmt
  11
  12#include <linux/efi.h>
  13#include <linux/fwnode.h>
  14#include <linux/init.h>
  15#include <linux/memblock.h>
  16#include <linux/mm_types.h>
  17#include <linux/of.h>
  18#include <linux/of_address.h>
  19#include <linux/of_fdt.h>
  20#include <linux/platform_device.h>
  21#include <linux/screen_info.h>
  22
  23#include <asm/efi.h>
  24
  25static int __init is_memory(efi_memory_desc_t *md)
  26{
  27        if (md->attribute & (EFI_MEMORY_WB|EFI_MEMORY_WT|EFI_MEMORY_WC))
  28                return 1;
  29        return 0;
  30}
  31
  32/*
  33 * Translate a EFI virtual address into a physical address: this is necessary,
  34 * as some data members of the EFI system table are virtually remapped after
  35 * SetVirtualAddressMap() has been called.
  36 */
  37static phys_addr_t __init efi_to_phys(unsigned long addr)
  38{
  39        efi_memory_desc_t *md;
  40
  41        for_each_efi_memory_desc(md) {
  42                if (!(md->attribute & EFI_MEMORY_RUNTIME))
  43                        continue;
  44                if (md->virt_addr == 0)
  45                        /* no virtual mapping has been installed by the stub */
  46                        break;
  47                if (md->virt_addr <= addr &&
  48                    (addr - md->virt_addr) < (md->num_pages << EFI_PAGE_SHIFT))
  49                        return md->phys_addr + addr - md->virt_addr;
  50        }
  51        return addr;
  52}
  53
  54static __initdata unsigned long screen_info_table = EFI_INVALID_TABLE_ADDR;
  55static __initdata unsigned long cpu_state_table = EFI_INVALID_TABLE_ADDR;
  56
  57static const efi_config_table_type_t arch_tables[] __initconst = {
  58        {LINUX_EFI_ARM_SCREEN_INFO_TABLE_GUID, &screen_info_table},
  59        {LINUX_EFI_ARM_CPU_STATE_TABLE_GUID, &cpu_state_table},
  60        {}
  61};
  62
  63static void __init init_screen_info(void)
  64{
  65        struct screen_info *si;
  66
  67        if (IS_ENABLED(CONFIG_ARM) &&
  68            screen_info_table != EFI_INVALID_TABLE_ADDR) {
  69                si = early_memremap_ro(screen_info_table, sizeof(*si));
  70                if (!si) {
  71                        pr_err("Could not map screen_info config table\n");
  72                        return;
  73                }
  74                screen_info = *si;
  75                early_memunmap(si, sizeof(*si));
  76
  77                /* dummycon on ARM needs non-zero values for columns/lines */
  78                screen_info.orig_video_cols = 80;
  79                screen_info.orig_video_lines = 25;
  80        }
  81
  82        if (screen_info.orig_video_isVGA == VIDEO_TYPE_EFI &&
  83            memblock_is_map_memory(screen_info.lfb_base))
  84                memblock_mark_nomap(screen_info.lfb_base, screen_info.lfb_size);
  85}
  86
  87static int __init uefi_init(u64 efi_system_table)
  88{
  89        efi_config_table_t *config_tables;
  90        efi_system_table_t *systab;
  91        size_t table_size;
  92        int retval;
  93
  94        systab = early_memremap_ro(efi_system_table, sizeof(efi_system_table_t));
  95        if (systab == NULL) {
  96                pr_warn("Unable to map EFI system table.\n");
  97                return -ENOMEM;
  98        }
  99
 100        set_bit(EFI_BOOT, &efi.flags);
 101        if (IS_ENABLED(CONFIG_64BIT))
 102                set_bit(EFI_64BIT, &efi.flags);
 103
 104        retval = efi_systab_check_header(&systab->hdr, 2);
 105        if (retval)
 106                goto out;
 107
 108        efi.runtime = systab->runtime;
 109        efi.runtime_version = systab->hdr.revision;
 110
 111        efi_systab_report_header(&systab->hdr, efi_to_phys(systab->fw_vendor));
 112
 113        table_size = sizeof(efi_config_table_t) * systab->nr_tables;
 114        config_tables = early_memremap_ro(efi_to_phys(systab->tables),
 115                                          table_size);
 116        if (config_tables == NULL) {
 117                pr_warn("Unable to map EFI config table array.\n");
 118                retval = -ENOMEM;
 119                goto out;
 120        }
 121        retval = efi_config_parse_tables(config_tables, systab->nr_tables,
 122                                         IS_ENABLED(CONFIG_ARM) ? arch_tables
 123                                                                : NULL);
 124
 125        early_memunmap(config_tables, table_size);
 126out:
 127        early_memunmap(systab, sizeof(efi_system_table_t));
 128        return retval;
 129}
 130
 131/*
 132 * Return true for regions that can be used as System RAM.
 133 */
 134static __init int is_usable_memory(efi_memory_desc_t *md)
 135{
 136        switch (md->type) {
 137        case EFI_LOADER_CODE:
 138        case EFI_LOADER_DATA:
 139        case EFI_ACPI_RECLAIM_MEMORY:
 140        case EFI_BOOT_SERVICES_CODE:
 141        case EFI_BOOT_SERVICES_DATA:
 142        case EFI_CONVENTIONAL_MEMORY:
 143        case EFI_PERSISTENT_MEMORY:
 144                /*
 145                 * Special purpose memory is 'soft reserved', which means it
 146                 * is set aside initially, but can be hotplugged back in or
 147                 * be assigned to the dax driver after boot.
 148                 */
 149                if (efi_soft_reserve_enabled() &&
 150                    (md->attribute & EFI_MEMORY_SP))
 151                        return false;
 152
 153                /*
 154                 * According to the spec, these regions are no longer reserved
 155                 * after calling ExitBootServices(). However, we can only use
 156                 * them as System RAM if they can be mapped writeback cacheable.
 157                 */
 158                return (md->attribute & EFI_MEMORY_WB);
 159        default:
 160                break;
 161        }
 162        return false;
 163}
 164
 165static __init void reserve_regions(void)
 166{
 167        efi_memory_desc_t *md;
 168        u64 paddr, npages, size;
 169
 170        if (efi_enabled(EFI_DBG))
 171                pr_info("Processing EFI memory map:\n");
 172
 173        /*
 174         * Discard memblocks discovered so far: if there are any at this
 175         * point, they originate from memory nodes in the DT, and UEFI
 176         * uses its own memory map instead.
 177         */
 178        memblock_dump_all();
 179        memblock_remove(0, PHYS_ADDR_MAX);
 180
 181        for_each_efi_memory_desc(md) {
 182                paddr = md->phys_addr;
 183                npages = md->num_pages;
 184
 185                if (efi_enabled(EFI_DBG)) {
 186                        char buf[64];
 187
 188                        pr_info("  0x%012llx-0x%012llx %s\n",
 189                                paddr, paddr + (npages << EFI_PAGE_SHIFT) - 1,
 190                                efi_md_typeattr_format(buf, sizeof(buf), md));
 191                }
 192
 193                memrange_efi_to_native(&paddr, &npages);
 194                size = npages << PAGE_SHIFT;
 195
 196                if (is_memory(md)) {
 197                        early_init_dt_add_memory_arch(paddr, size);
 198
 199                        if (!is_usable_memory(md))
 200                                memblock_mark_nomap(paddr, size);
 201
 202                        /* keep ACPI reclaim memory intact for kexec etc. */
 203                        if (md->type == EFI_ACPI_RECLAIM_MEMORY)
 204                                memblock_reserve(paddr, size);
 205                }
 206        }
 207}
 208
 209void __init efi_init(void)
 210{
 211        struct efi_memory_map_data data;
 212        u64 efi_system_table;
 213
 214        /* Grab UEFI information placed in FDT by stub */
 215        efi_system_table = efi_get_fdt_params(&data);
 216        if (!efi_system_table)
 217                return;
 218
 219        if (efi_memmap_init_early(&data) < 0) {
 220                /*
 221                * If we are booting via UEFI, the UEFI memory map is the only
 222                * description of memory we have, so there is little point in
 223                * proceeding if we cannot access it.
 224                */
 225                panic("Unable to map EFI memory map.\n");
 226        }
 227
 228        WARN(efi.memmap.desc_version != 1,
 229             "Unexpected EFI_MEMORY_DESCRIPTOR version %ld",
 230              efi.memmap.desc_version);
 231
 232        if (uefi_init(efi_system_table) < 0) {
 233                efi_memmap_unmap();
 234                return;
 235        }
 236
 237        reserve_regions();
 238        efi_esrt_init();
 239        efi_mokvar_table_init();
 240
 241        memblock_reserve(data.phys_map & PAGE_MASK,
 242                         PAGE_ALIGN(data.size + (data.phys_map & ~PAGE_MASK)));
 243
 244        init_screen_info();
 245
 246#ifdef CONFIG_ARM
 247        /* ARM does not permit early mappings to persist across paging_init() */
 248        efi_memmap_unmap();
 249
 250        if (cpu_state_table != EFI_INVALID_TABLE_ADDR) {
 251                struct efi_arm_entry_state *state;
 252                bool dump_state = true;
 253
 254                state = early_memremap_ro(cpu_state_table,
 255                                          sizeof(struct efi_arm_entry_state));
 256                if (state == NULL) {
 257                        pr_warn("Unable to map CPU entry state table.\n");
 258                        return;
 259                }
 260
 261                if ((state->sctlr_before_ebs & 1) == 0)
 262                        pr_warn(FW_BUG "EFI stub was entered with MMU and Dcache disabled, please fix your firmware!\n");
 263                else if ((state->sctlr_after_ebs & 1) == 0)
 264                        pr_warn(FW_BUG "ExitBootServices() returned with MMU and Dcache disabled, please fix your firmware!\n");
 265                else
 266                        dump_state = false;
 267
 268                if (dump_state || efi_enabled(EFI_DBG)) {
 269                        pr_info("CPSR at EFI stub entry        : 0x%08x\n", state->cpsr_before_ebs);
 270                        pr_info("SCTLR at EFI stub entry       : 0x%08x\n", state->sctlr_before_ebs);
 271                        pr_info("CPSR after ExitBootServices() : 0x%08x\n", state->cpsr_after_ebs);
 272                        pr_info("SCTLR after ExitBootServices(): 0x%08x\n", state->sctlr_after_ebs);
 273                }
 274                early_memunmap(state, sizeof(struct efi_arm_entry_state));
 275        }
 276#endif
 277}
 278