1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * Author: Erik Kaneda <erik.kaneda@intel.com> 4 * Copyright 2020 Intel Corporation 5 * 6 * prmt.c 7 * 8 * Each PRM service is an executable that is run in a restricted environment 9 * that is invoked by writing to the PlatformRtMechanism OperationRegion from 10 * AML bytecode. 11 * 12 * init_prmt initializes the Platform Runtime Mechanism (PRM) services by 13 * processing data in the PRMT as well as registering an ACPI OperationRegion 14 * handler for the PlatformRtMechanism subtype. 15 * 16 */ 17 #include <linux/kernel.h> 18 #include <linux/efi.h> 19 #include <linux/acpi.h> 20 #include <linux/prmt.h> 21 #include <asm/efi.h> 22 23 #pragma pack(1) 24 struct prm_mmio_addr_range { 25 u64 phys_addr; 26 u64 virt_addr; 27 u32 length; 28 }; 29 30 struct prm_mmio_info { 31 u64 mmio_count; 32 struct prm_mmio_addr_range addr_ranges[]; 33 }; 34 35 struct prm_buffer { 36 u8 prm_status; 37 u64 efi_status; 38 u8 prm_cmd; 39 guid_t handler_guid; 40 }; 41 42 struct prm_context_buffer { 43 char signature[ACPI_NAMESEG_SIZE]; 44 u16 revision; 45 u16 reserved; 46 guid_t identifier; 47 u64 static_data_buffer; 48 struct prm_mmio_info *mmio_ranges; 49 }; 50 #pragma pack() 51 52 static LIST_HEAD(prm_module_list); 53 54 struct prm_handler_info { 55 guid_t guid; 56 efi_status_t (__efiapi *handler_addr)(u64, void *); 57 u64 static_data_buffer_addr; 58 u64 acpi_param_buffer_addr; 59 60 struct list_head handler_list; 61 }; 62 63 struct prm_module_info { 64 guid_t guid; 65 u16 major_rev; 66 u16 minor_rev; 67 u16 handler_count; 68 struct prm_mmio_info *mmio_info; 69 bool updatable; 70 71 struct list_head module_list; 72 struct prm_handler_info handlers[] __counted_by(handler_count); 73 }; 74 75 static u64 efi_pa_va_lookup(u64 pa) 76 { 77 efi_memory_desc_t *md; 78 u64 pa_offset = pa & ~PAGE_MASK; 79 u64 page = pa & PAGE_MASK; 80 81 for_each_efi_memory_desc(md) { 82 if (md->phys_addr < pa && pa < md->phys_addr + PAGE_SIZE * md->num_pages) 83 return pa_offset + md->virt_addr + page - md->phys_addr; 84 } 85 86 return 0; 87 } 88 89 #define get_first_handler(a) ((struct acpi_prmt_handler_info *) ((char *) (a) + a->handler_info_offset)) 90 #define get_next_handler(a) ((struct acpi_prmt_handler_info *) (sizeof(struct acpi_prmt_handler_info) + (char *) a)) 91 92 static int __init 93 acpi_parse_prmt(union acpi_subtable_headers *header, const unsigned long end) 94 { 95 struct acpi_prmt_module_info *module_info; 96 struct acpi_prmt_handler_info *handler_info; 97 struct prm_handler_info *th; 98 struct prm_module_info *tm; 99 u64 *mmio_count; 100 u64 cur_handler = 0; 101 u32 module_info_size = 0; 102 u64 mmio_range_size = 0; 103 void *temp_mmio; 104 105 module_info = (struct acpi_prmt_module_info *) header; 106 module_info_size = struct_size(tm, handlers, module_info->handler_info_count); 107 tm = kmalloc(module_info_size, GFP_KERNEL); 108 if (!tm) 109 goto parse_prmt_out1; 110 111 guid_copy(&tm->guid, (guid_t *) module_info->module_guid); 112 tm->major_rev = module_info->major_rev; 113 tm->minor_rev = module_info->minor_rev; 114 tm->handler_count = module_info->handler_info_count; 115 tm->updatable = true; 116 117 if (module_info->mmio_list_pointer) { 118 /* 119 * Each module is associated with a list of addr 120 * ranges that it can use during the service 121 */ 122 mmio_count = (u64 *) memremap(module_info->mmio_list_pointer, 8, MEMREMAP_WB); 123 if (!mmio_count) 124 goto parse_prmt_out2; 125 126 mmio_range_size = struct_size(tm->mmio_info, addr_ranges, *mmio_count); 127 tm->mmio_info = kmalloc(mmio_range_size, GFP_KERNEL); 128 if (!tm->mmio_info) 129 goto parse_prmt_out3; 130 131 temp_mmio = memremap(module_info->mmio_list_pointer, mmio_range_size, MEMREMAP_WB); 132 if (!temp_mmio) 133 goto parse_prmt_out4; 134 memmove(tm->mmio_info, temp_mmio, mmio_range_size); 135 } else { 136 tm->mmio_info = kmalloc(sizeof(*tm->mmio_info), GFP_KERNEL); 137 if (!tm->mmio_info) 138 goto parse_prmt_out2; 139 140 tm->mmio_info->mmio_count = 0; 141 } 142 143 INIT_LIST_HEAD(&tm->module_list); 144 list_add(&tm->module_list, &prm_module_list); 145 146 handler_info = get_first_handler(module_info); 147 do { 148 th = &tm->handlers[cur_handler]; 149 150 guid_copy(&th->guid, (guid_t *)handler_info->handler_guid); 151 th->handler_addr = (void *)efi_pa_va_lookup(handler_info->handler_address); 152 th->static_data_buffer_addr = efi_pa_va_lookup(handler_info->static_data_buffer_address); 153 th->acpi_param_buffer_addr = efi_pa_va_lookup(handler_info->acpi_param_buffer_address); 154 } while (++cur_handler < tm->handler_count && (handler_info = get_next_handler(handler_info))); 155 156 return 0; 157 158 parse_prmt_out4: 159 kfree(tm->mmio_info); 160 parse_prmt_out3: 161 memunmap(mmio_count); 162 parse_prmt_out2: 163 kfree(tm); 164 parse_prmt_out1: 165 return -ENOMEM; 166 } 167 168 #define GET_MODULE 0 169 #define GET_HANDLER 1 170 171 static void *find_guid_info(const guid_t *guid, u8 mode) 172 { 173 struct prm_handler_info *cur_handler; 174 struct prm_module_info *cur_module; 175 int i = 0; 176 177 list_for_each_entry(cur_module, &prm_module_list, module_list) { 178 for (i = 0; i < cur_module->handler_count; ++i) { 179 cur_handler = &cur_module->handlers[i]; 180 if (guid_equal(guid, &cur_handler->guid)) { 181 if (mode == GET_MODULE) 182 return (void *)cur_module; 183 else 184 return (void *)cur_handler; 185 } 186 } 187 } 188 189 return NULL; 190 } 191 192 static struct prm_module_info *find_prm_module(const guid_t *guid) 193 { 194 return (struct prm_module_info *)find_guid_info(guid, GET_MODULE); 195 } 196 197 static struct prm_handler_info *find_prm_handler(const guid_t *guid) 198 { 199 return (struct prm_handler_info *) find_guid_info(guid, GET_HANDLER); 200 } 201 202 /* In-coming PRM commands */ 203 204 #define PRM_CMD_RUN_SERVICE 0 205 #define PRM_CMD_START_TRANSACTION 1 206 #define PRM_CMD_END_TRANSACTION 2 207 208 /* statuses that can be passed back to ASL */ 209 210 #define PRM_HANDLER_SUCCESS 0 211 #define PRM_HANDLER_ERROR 1 212 #define INVALID_PRM_COMMAND 2 213 #define PRM_HANDLER_GUID_NOT_FOUND 3 214 #define UPDATE_LOCK_ALREADY_HELD 4 215 #define UPDATE_UNLOCK_WITHOUT_LOCK 5 216 217 /* 218 * This is the PlatformRtMechanism opregion space handler. 219 * @function: indicates the read/write. In fact as the PlatformRtMechanism 220 * message is driven by command, only write is meaningful. 221 * 222 * @addr : not used 223 * @bits : not used. 224 * @value : it is an in/out parameter. It points to the PRM message buffer. 225 * @handler_context: not used 226 */ 227 static acpi_status acpi_platformrt_space_handler(u32 function, 228 acpi_physical_address addr, 229 u32 bits, acpi_integer *value, 230 void *handler_context, 231 void *region_context) 232 { 233 struct prm_buffer *buffer = ACPI_CAST_PTR(struct prm_buffer, value); 234 struct prm_handler_info *handler; 235 struct prm_module_info *module; 236 efi_status_t status; 237 struct prm_context_buffer context; 238 239 if (!efi_enabled(EFI_RUNTIME_SERVICES)) { 240 pr_err_ratelimited("PRM: EFI runtime services no longer available\n"); 241 return AE_NO_HANDLER; 242 } 243 244 /* 245 * The returned acpi_status will always be AE_OK. Error values will be 246 * saved in the first byte of the PRM message buffer to be used by ASL. 247 */ 248 switch (buffer->prm_cmd) { 249 case PRM_CMD_RUN_SERVICE: 250 251 handler = find_prm_handler(&buffer->handler_guid); 252 module = find_prm_module(&buffer->handler_guid); 253 if (!handler || !module) 254 goto invalid_guid; 255 256 ACPI_COPY_NAMESEG(context.signature, "PRMC"); 257 context.revision = 0x0; 258 context.reserved = 0x0; 259 context.identifier = handler->guid; 260 context.static_data_buffer = handler->static_data_buffer_addr; 261 context.mmio_ranges = module->mmio_info; 262 263 status = efi_call_acpi_prm_handler(handler->handler_addr, 264 handler->acpi_param_buffer_addr, 265 &context); 266 if (status == EFI_SUCCESS) { 267 buffer->prm_status = PRM_HANDLER_SUCCESS; 268 } else { 269 buffer->prm_status = PRM_HANDLER_ERROR; 270 buffer->efi_status = status; 271 } 272 break; 273 274 case PRM_CMD_START_TRANSACTION: 275 276 module = find_prm_module(&buffer->handler_guid); 277 if (!module) 278 goto invalid_guid; 279 280 if (module->updatable) 281 module->updatable = false; 282 else 283 buffer->prm_status = UPDATE_LOCK_ALREADY_HELD; 284 break; 285 286 case PRM_CMD_END_TRANSACTION: 287 288 module = find_prm_module(&buffer->handler_guid); 289 if (!module) 290 goto invalid_guid; 291 292 if (module->updatable) 293 buffer->prm_status = UPDATE_UNLOCK_WITHOUT_LOCK; 294 else 295 module->updatable = true; 296 break; 297 298 default: 299 300 buffer->prm_status = INVALID_PRM_COMMAND; 301 break; 302 } 303 304 return AE_OK; 305 306 invalid_guid: 307 buffer->prm_status = PRM_HANDLER_GUID_NOT_FOUND; 308 return AE_OK; 309 } 310 311 void __init init_prmt(void) 312 { 313 struct acpi_table_header *tbl; 314 acpi_status status; 315 int mc; 316 317 status = acpi_get_table(ACPI_SIG_PRMT, 0, &tbl); 318 if (ACPI_FAILURE(status)) 319 return; 320 321 mc = acpi_table_parse_entries(ACPI_SIG_PRMT, sizeof(struct acpi_table_prmt) + 322 sizeof (struct acpi_table_prmt_header), 323 0, acpi_parse_prmt, 0); 324 acpi_put_table(tbl); 325 /* 326 * Return immediately if PRMT table is not present or no PRM module found. 327 */ 328 if (mc <= 0) 329 return; 330 331 pr_info("PRM: found %u modules\n", mc); 332 333 if (!efi_enabled(EFI_RUNTIME_SERVICES)) { 334 pr_err("PRM: EFI runtime services unavailable\n"); 335 return; 336 } 337 338 status = acpi_install_address_space_handler(ACPI_ROOT_OBJECT, 339 ACPI_ADR_SPACE_PLATFORM_RT, 340 &acpi_platformrt_space_handler, 341 NULL, NULL); 342 if (ACPI_FAILURE(status)) 343 pr_alert("PRM: OperationRegion handler could not be installed\n"); 344 } 345