1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * Author: Erik Kaneda <[email protected]> 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 u64 handler_addr; 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[]; 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 = 0; 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); 108 109 guid_copy(&tm->guid, (guid_t *) module_info->module_guid); 110 tm->major_rev = module_info->major_rev; 111 tm->minor_rev = module_info->minor_rev; 112 tm->handler_count = module_info->handler_info_count; 113 tm->updatable = true; 114 115 if (module_info->mmio_list_pointer) { 116 /* 117 * Each module is associated with a list of addr 118 * ranges that it can use during the service 119 */ 120 mmio_count = *(u64 *) memremap(module_info->mmio_list_pointer, 8, MEMREMAP_WB); 121 mmio_range_size = struct_size(tm->mmio_info, addr_ranges, mmio_count); 122 tm->mmio_info = kmalloc(mmio_range_size, GFP_KERNEL); 123 temp_mmio = memremap(module_info->mmio_list_pointer, mmio_range_size, MEMREMAP_WB); 124 memmove(tm->mmio_info, temp_mmio, mmio_range_size); 125 } else { 126 mmio_range_size = struct_size(tm->mmio_info, addr_ranges, mmio_count); 127 tm->mmio_info = kmalloc(mmio_range_size, GFP_KERNEL); 128 tm->mmio_info->mmio_count = 0; 129 } 130 131 INIT_LIST_HEAD(&tm->module_list); 132 list_add(&tm->module_list, &prm_module_list); 133 134 handler_info = get_first_handler(module_info); 135 do { 136 th = &tm->handlers[cur_handler]; 137 138 guid_copy(&th->guid, (guid_t *)handler_info->handler_guid); 139 th->handler_addr = efi_pa_va_lookup(handler_info->handler_address); 140 th->static_data_buffer_addr = efi_pa_va_lookup(handler_info->static_data_buffer_address); 141 th->acpi_param_buffer_addr = efi_pa_va_lookup(handler_info->acpi_param_buffer_address); 142 } while (++cur_handler < tm->handler_count && (handler_info = get_next_handler(handler_info))); 143 144 return 0; 145 } 146 147 #define GET_MODULE 0 148 #define GET_HANDLER 1 149 150 static void *find_guid_info(const guid_t *guid, u8 mode) 151 { 152 struct prm_handler_info *cur_handler; 153 struct prm_module_info *cur_module; 154 int i = 0; 155 156 list_for_each_entry(cur_module, &prm_module_list, module_list) { 157 for (i = 0; i < cur_module->handler_count; ++i) { 158 cur_handler = &cur_module->handlers[i]; 159 if (guid_equal(guid, &cur_handler->guid)) { 160 if (mode == GET_MODULE) 161 return (void *)cur_module; 162 else 163 return (void *)cur_handler; 164 } 165 } 166 } 167 168 return NULL; 169 } 170 171 static struct prm_module_info *find_prm_module(const guid_t *guid) 172 { 173 return (struct prm_module_info *)find_guid_info(guid, GET_MODULE); 174 } 175 176 static struct prm_handler_info *find_prm_handler(const guid_t *guid) 177 { 178 return (struct prm_handler_info *) find_guid_info(guid, GET_HANDLER); 179 } 180 181 /* In-coming PRM commands */ 182 183 #define PRM_CMD_RUN_SERVICE 0 184 #define PRM_CMD_START_TRANSACTION 1 185 #define PRM_CMD_END_TRANSACTION 2 186 187 /* statuses that can be passed back to ASL */ 188 189 #define PRM_HANDLER_SUCCESS 0 190 #define PRM_HANDLER_ERROR 1 191 #define INVALID_PRM_COMMAND 2 192 #define PRM_HANDLER_GUID_NOT_FOUND 3 193 #define UPDATE_LOCK_ALREADY_HELD 4 194 #define UPDATE_UNLOCK_WITHOUT_LOCK 5 195 196 /* 197 * This is the PlatformRtMechanism opregion space handler. 198 * @function: indicates the read/write. In fact as the PlatformRtMechanism 199 * message is driven by command, only write is meaningful. 200 * 201 * @addr : not used 202 * @bits : not used. 203 * @value : it is an in/out parameter. It points to the PRM message buffer. 204 * @handler_context: not used 205 */ 206 static acpi_status acpi_platformrt_space_handler(u32 function, 207 acpi_physical_address addr, 208 u32 bits, acpi_integer *value, 209 void *handler_context, 210 void *region_context) 211 { 212 struct prm_buffer *buffer = ACPI_CAST_PTR(struct prm_buffer, value); 213 struct prm_handler_info *handler; 214 struct prm_module_info *module; 215 efi_status_t status; 216 struct prm_context_buffer context; 217 218 /* 219 * The returned acpi_status will always be AE_OK. Error values will be 220 * saved in the first byte of the PRM message buffer to be used by ASL. 221 */ 222 switch (buffer->prm_cmd) { 223 case PRM_CMD_RUN_SERVICE: 224 225 handler = find_prm_handler(&buffer->handler_guid); 226 module = find_prm_module(&buffer->handler_guid); 227 if (!handler || !module) 228 goto invalid_guid; 229 230 ACPI_COPY_NAMESEG(context.signature, "PRMC"); 231 context.revision = 0x0; 232 context.reserved = 0x0; 233 context.identifier = handler->guid; 234 context.static_data_buffer = handler->static_data_buffer_addr; 235 context.mmio_ranges = module->mmio_info; 236 237 status = efi_call_virt_pointer(handler, handler_addr, 238 handler->acpi_param_buffer_addr, 239 &context); 240 if (status == EFI_SUCCESS) { 241 buffer->prm_status = PRM_HANDLER_SUCCESS; 242 } else { 243 buffer->prm_status = PRM_HANDLER_ERROR; 244 buffer->efi_status = status; 245 } 246 break; 247 248 case PRM_CMD_START_TRANSACTION: 249 250 module = find_prm_module(&buffer->handler_guid); 251 if (!module) 252 goto invalid_guid; 253 254 if (module->updatable) 255 module->updatable = false; 256 else 257 buffer->prm_status = UPDATE_LOCK_ALREADY_HELD; 258 break; 259 260 case PRM_CMD_END_TRANSACTION: 261 262 module = find_prm_module(&buffer->handler_guid); 263 if (!module) 264 goto invalid_guid; 265 266 if (module->updatable) 267 buffer->prm_status = UPDATE_UNLOCK_WITHOUT_LOCK; 268 else 269 module->updatable = true; 270 break; 271 272 default: 273 274 buffer->prm_status = INVALID_PRM_COMMAND; 275 break; 276 } 277 278 return AE_OK; 279 280 invalid_guid: 281 buffer->prm_status = PRM_HANDLER_GUID_NOT_FOUND; 282 return AE_OK; 283 } 284 285 void __init init_prmt(void) 286 { 287 struct acpi_table_header *tbl; 288 acpi_status status; 289 int mc; 290 291 status = acpi_get_table(ACPI_SIG_PRMT, 0, &tbl); 292 if (ACPI_FAILURE(status)) 293 return; 294 295 mc = acpi_table_parse_entries(ACPI_SIG_PRMT, sizeof(struct acpi_table_prmt) + 296 sizeof (struct acpi_table_prmt_header), 297 0, acpi_parse_prmt, 0); 298 acpi_put_table(tbl); 299 /* 300 * Return immediately if PRMT table is not present or no PRM module found. 301 */ 302 if (mc <= 0) 303 return; 304 305 pr_info("PRM: found %u modules\n", mc); 306 307 status = acpi_install_address_space_handler(ACPI_ROOT_OBJECT, 308 ACPI_ADR_SPACE_PLATFORM_RT, 309 &acpi_platformrt_space_handler, 310 NULL, NULL); 311 if (ACPI_FAILURE(status)) 312 pr_alert("PRM: OperationRegion handler could not be installed\n"); 313 } 314