1 #include <linux/init.h> 2 #include <linux/kernel.h> 3 #include <linux/string.h> 4 #include <linux/time.h> 5 #include <linux/types.h> 6 #include <linux/efi.h> 7 #include <linux/slab.h> 8 #include <linux/memblock.h> 9 #include <linux/bootmem.h> 10 #include <linux/acpi.h> 11 #include <linux/dmi.h> 12 #include <asm/efi.h> 13 #include <asm/uv/uv.h> 14 15 #define EFI_MIN_RESERVE 5120 16 17 #define EFI_DUMMY_GUID \ 18 EFI_GUID(0x4424ac57, 0xbe4b, 0x47dd, 0x9e, 0x97, 0xed, 0x50, 0xf0, 0x9f, 0x92, 0xa9) 19 20 static efi_char16_t efi_dummy_name[6] = { 'D', 'U', 'M', 'M', 'Y', 0 }; 21 22 static bool efi_no_storage_paranoia; 23 24 /* 25 * Some firmware implementations refuse to boot if there's insufficient 26 * space in the variable store. The implementation of garbage collection 27 * in some FW versions causes stale (deleted) variables to take up space 28 * longer than intended and space is only freed once the store becomes 29 * almost completely full. 30 * 31 * Enabling this option disables the space checks in 32 * efi_query_variable_store() and forces garbage collection. 33 * 34 * Only enable this option if deleting EFI variables does not free up 35 * space in your variable store, e.g. if despite deleting variables 36 * you're unable to create new ones. 37 */ 38 static int __init setup_storage_paranoia(char *arg) 39 { 40 efi_no_storage_paranoia = true; 41 return 0; 42 } 43 early_param("efi_no_storage_paranoia", setup_storage_paranoia); 44 45 /* 46 * Deleting the dummy variable which kicks off garbage collection 47 */ 48 void efi_delete_dummy_variable(void) 49 { 50 efi.set_variable(efi_dummy_name, &EFI_DUMMY_GUID, 51 EFI_VARIABLE_NON_VOLATILE | 52 EFI_VARIABLE_BOOTSERVICE_ACCESS | 53 EFI_VARIABLE_RUNTIME_ACCESS, 54 0, NULL); 55 } 56 57 /* 58 * Some firmware implementations refuse to boot if there's insufficient space 59 * in the variable store. Ensure that we never use more than a safe limit. 60 * 61 * Return EFI_SUCCESS if it is safe to write 'size' bytes to the variable 62 * store. 63 */ 64 efi_status_t efi_query_variable_store(u32 attributes, unsigned long size) 65 { 66 efi_status_t status; 67 u64 storage_size, remaining_size, max_size; 68 69 if (!(attributes & EFI_VARIABLE_NON_VOLATILE)) 70 return 0; 71 72 status = efi.query_variable_info(attributes, &storage_size, 73 &remaining_size, &max_size); 74 if (status != EFI_SUCCESS) 75 return status; 76 77 /* 78 * We account for that by refusing the write if permitting it would 79 * reduce the available space to under 5KB. This figure was provided by 80 * Samsung, so should be safe. 81 */ 82 if ((remaining_size - size < EFI_MIN_RESERVE) && 83 !efi_no_storage_paranoia) { 84 85 /* 86 * Triggering garbage collection may require that the firmware 87 * generate a real EFI_OUT_OF_RESOURCES error. We can force 88 * that by attempting to use more space than is available. 89 */ 90 unsigned long dummy_size = remaining_size + 1024; 91 void *dummy = kzalloc(dummy_size, GFP_ATOMIC); 92 93 if (!dummy) 94 return EFI_OUT_OF_RESOURCES; 95 96 status = efi.set_variable(efi_dummy_name, &EFI_DUMMY_GUID, 97 EFI_VARIABLE_NON_VOLATILE | 98 EFI_VARIABLE_BOOTSERVICE_ACCESS | 99 EFI_VARIABLE_RUNTIME_ACCESS, 100 dummy_size, dummy); 101 102 if (status == EFI_SUCCESS) { 103 /* 104 * This should have failed, so if it didn't make sure 105 * that we delete it... 106 */ 107 efi_delete_dummy_variable(); 108 } 109 110 kfree(dummy); 111 112 /* 113 * The runtime code may now have triggered a garbage collection 114 * run, so check the variable info again 115 */ 116 status = efi.query_variable_info(attributes, &storage_size, 117 &remaining_size, &max_size); 118 119 if (status != EFI_SUCCESS) 120 return status; 121 122 /* 123 * There still isn't enough room, so return an error 124 */ 125 if (remaining_size - size < EFI_MIN_RESERVE) 126 return EFI_OUT_OF_RESOURCES; 127 } 128 129 return EFI_SUCCESS; 130 } 131 EXPORT_SYMBOL_GPL(efi_query_variable_store); 132 133 /* 134 * The UEFI specification makes it clear that the operating system is free to do 135 * whatever it wants with boot services code after ExitBootServices() has been 136 * called. Ignoring this recommendation a significant bunch of EFI implementations 137 * continue calling into boot services code (SetVirtualAddressMap). In order to 138 * work around such buggy implementations we reserve boot services region during 139 * EFI init and make sure it stays executable. Then, after SetVirtualAddressMap(), it 140 * is discarded. 141 */ 142 void __init efi_reserve_boot_services(void) 143 { 144 void *p; 145 146 for (p = memmap.map; p < memmap.map_end; p += memmap.desc_size) { 147 efi_memory_desc_t *md = p; 148 u64 start = md->phys_addr; 149 u64 size = md->num_pages << EFI_PAGE_SHIFT; 150 151 if (md->type != EFI_BOOT_SERVICES_CODE && 152 md->type != EFI_BOOT_SERVICES_DATA) 153 continue; 154 /* Only reserve where possible: 155 * - Not within any already allocated areas 156 * - Not over any memory area (really needed, if above?) 157 * - Not within any part of the kernel 158 * - Not the bios reserved area 159 */ 160 if ((start + size > __pa_symbol(_text) 161 && start <= __pa_symbol(_end)) || 162 !e820_all_mapped(start, start+size, E820_RAM) || 163 memblock_is_region_reserved(start, size)) { 164 /* Could not reserve, skip it */ 165 md->num_pages = 0; 166 memblock_dbg("Could not reserve boot range [0x%010llx-0x%010llx]\n", 167 start, start+size-1); 168 } else 169 memblock_reserve(start, size); 170 } 171 } 172 173 void __init efi_free_boot_services(void) 174 { 175 void *p; 176 177 for (p = memmap.map; p < memmap.map_end; p += memmap.desc_size) { 178 efi_memory_desc_t *md = p; 179 unsigned long long start = md->phys_addr; 180 unsigned long long size = md->num_pages << EFI_PAGE_SHIFT; 181 182 if (md->type != EFI_BOOT_SERVICES_CODE && 183 md->type != EFI_BOOT_SERVICES_DATA) 184 continue; 185 186 /* Could not reserve boot area */ 187 if (!size) 188 continue; 189 190 free_bootmem_late(start, size); 191 } 192 193 efi_unmap_memmap(); 194 } 195 196 /* 197 * A number of config table entries get remapped to virtual addresses 198 * after entering EFI virtual mode. However, the kexec kernel requires 199 * their physical addresses therefore we pass them via setup_data and 200 * correct those entries to their respective physical addresses here. 201 * 202 * Currently only handles smbios which is necessary for some firmware 203 * implementation. 204 */ 205 int __init efi_reuse_config(u64 tables, int nr_tables) 206 { 207 int i, sz, ret = 0; 208 void *p, *tablep; 209 struct efi_setup_data *data; 210 211 if (!efi_setup) 212 return 0; 213 214 if (!efi_enabled(EFI_64BIT)) 215 return 0; 216 217 data = early_memremap(efi_setup, sizeof(*data)); 218 if (!data) { 219 ret = -ENOMEM; 220 goto out; 221 } 222 223 if (!data->smbios) 224 goto out_memremap; 225 226 sz = sizeof(efi_config_table_64_t); 227 228 p = tablep = early_memremap(tables, nr_tables * sz); 229 if (!p) { 230 pr_err("Could not map Configuration table!\n"); 231 ret = -ENOMEM; 232 goto out_memremap; 233 } 234 235 for (i = 0; i < efi.systab->nr_tables; i++) { 236 efi_guid_t guid; 237 238 guid = ((efi_config_table_64_t *)p)->guid; 239 240 if (!efi_guidcmp(guid, SMBIOS_TABLE_GUID)) 241 ((efi_config_table_64_t *)p)->table = data->smbios; 242 p += sz; 243 } 244 early_memunmap(tablep, nr_tables * sz); 245 246 out_memremap: 247 early_memunmap(data, sizeof(*data)); 248 out: 249 return ret; 250 } 251 252 static const struct dmi_system_id sgi_uv1_dmi[] = { 253 { NULL, "SGI UV1", 254 { DMI_MATCH(DMI_PRODUCT_NAME, "Stoutland Platform"), 255 DMI_MATCH(DMI_PRODUCT_VERSION, "1.0"), 256 DMI_MATCH(DMI_BIOS_VENDOR, "SGI.COM"), 257 } 258 }, 259 { } /* NULL entry stops DMI scanning */ 260 }; 261 262 void __init efi_apply_memmap_quirks(void) 263 { 264 /* 265 * Once setup is done earlier, unmap the EFI memory map on mismatched 266 * firmware/kernel architectures since there is no support for runtime 267 * services. 268 */ 269 if (!efi_runtime_supported()) { 270 pr_info("efi: Setup done, disabling due to 32/64-bit mismatch\n"); 271 efi_unmap_memmap(); 272 } 273 274 /* UV2+ BIOS has a fix for this issue. UV1 still needs the quirk. */ 275 if (dmi_check_system(sgi_uv1_dmi)) 276 set_bit(EFI_OLD_MEMMAP, &efi.flags); 277 } 278 279 /* 280 * For most modern platforms the preferred method of powering off is via 281 * ACPI. However, there are some that are known to require the use of 282 * EFI runtime services and for which ACPI does not work at all. 283 * 284 * Using EFI is a last resort, to be used only if no other option 285 * exists. 286 */ 287 bool efi_reboot_required(void) 288 { 289 if (!acpi_gbl_reduced_hardware) 290 return false; 291 292 efi_reboot_quirk_mode = EFI_RESET_WARM; 293 return true; 294 } 295 296 bool efi_poweroff_required(void) 297 { 298 return !!acpi_gbl_reduced_hardware; 299 } 300