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
  25 static 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  */
  37 static 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
  54 static __initdata unsigned long screen_info_table = EFI_INVALID_TABLE_ADDR;
  55 static __initdata unsigned long cpu_state_table = EFI_INVALID_TABLE_ADDR;
  56
  57 static 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
  63 static 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
  87 static 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);
 126 out:
 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  */
 134 static __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
 165 static __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
 209 void __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
 279 static bool efifb_overlaps_pci_range(const struct of_pci_range *range)
 280 {
 281         u64 fb_base = screen_info.lfb_base;
 282
 283         if (screen_info.capabilities & VIDEO_CAPABILITY_64BIT_BASE)
 284                 fb_base |= (u64)(unsigned long)screen_info.ext_lfb_base << 32;
 285
 286         return fb_base >= range->cpu_addr &&
 287                fb_base < (range->cpu_addr + range->size);
 288 }
 289
 290 static struct device_node *find_pci_overlap_node(void)
 291 {
 292         struct device_node *np;
 293
 294         for_each_node_by_type(np, "pci") {
 295                 struct of_pci_range_parser parser;
 296                 struct of_pci_range range;
 297                 int err;
 298
 299                 err = of_pci_range_parser_init(&parser, np);
 300                 if (err) {
 301                         pr_warn("of_pci_range_parser_init() failed: %d\n", err);
 302                         continue;
 303                 }
 304
 305                 for_each_of_pci_range(&parser, &range)
 306                         if (efifb_overlaps_pci_range(&range))
 307                                 return np;
 308         }
 309         return NULL;
 310 }
 311
 312 /*
 313  * If the efifb framebuffer is backed by a PCI graphics controller, we have
 314  * to ensure that this relation is expressed using a device link when
 315  * running in DT mode, or the probe order may be reversed, resulting in a
 316  * resource reservation conflict on the memory window that the efifb
 317  * framebuffer steals from the PCIe host bridge.
 318  */
 319 static int efifb_add_links(struct fwnode_handle *fwnode)
 320 {
 321         struct device_node *sup_np;
 322
 323         sup_np = find_pci_overlap_node();
 324
 325         /*
 326          * If there's no PCI graphics controller backing the efifb, we are
 327          * done here.
 328          */
 329         if (!sup_np)
 330                 return 0;
 331
 332         fwnode_link_add(fwnode, of_fwnode_handle(sup_np));
 333         of_node_put(sup_np);
 334
 335         return 0;
 336 }
 337
 338 static const struct fwnode_operations efifb_fwnode_ops = {
 339         .add_links = efifb_add_links,
 340 };
 341
 342 static struct fwnode_handle efifb_fwnode;
 343
 344 static int __init register_gop_device(void)
 345 {
 346         struct platform_device *pd;
 347         int err;
 348
 349         if (screen_info.orig_video_isVGA != VIDEO_TYPE_EFI)
 350                 return 0;
 351
 352         pd = platform_device_alloc("efi-framebuffer", 0);
 353         if (!pd)
 354                 return -ENOMEM;
 355
 356         if (IS_ENABLED(CONFIG_PCI)) {
 357                 fwnode_init(&efifb_fwnode, &efifb_fwnode_ops);
 358                 pd->dev.fwnode = &efifb_fwnode;
 359         }
 360
 361         err = platform_device_add_data(pd, &screen_info, sizeof(screen_info));
 362         if (err)
 363                 return err;
 364
 365         return platform_device_add(pd);
 366 }
 367 subsys_initcall(register_gop_device);