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 efi_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
efi_pa_va_lookup(efi_guid_t * guid,u64 pa)75 static u64 efi_pa_va_lookup(efi_guid_t *guid, 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->attribute & EFI_MEMORY_RUNTIME) &&
83 (md->phys_addr < pa && pa < md->phys_addr + PAGE_SIZE * md->num_pages)) {
84 return pa_offset + md->virt_addr + page - md->phys_addr;
85 }
86 }
87
88 return 0;
89 }
90
91 #define get_first_handler(a) ((struct acpi_prmt_handler_info *) ((char *) (a) + a->handler_info_offset))
92 #define get_next_handler(a) ((struct acpi_prmt_handler_info *) (sizeof(struct acpi_prmt_handler_info) + (char *) a))
93
94 static int __init
acpi_parse_prmt(union acpi_subtable_headers * header,const unsigned long end)95 acpi_parse_prmt(union acpi_subtable_headers *header, const unsigned long end)
96 {
97 struct acpi_prmt_module_info *module_info;
98 struct acpi_prmt_handler_info *handler_info;
99 struct prm_handler_info *th;
100 struct prm_module_info *tm;
101 u64 *mmio_count;
102 u64 cur_handler = 0;
103 u32 module_info_size = 0;
104 u64 mmio_range_size = 0;
105 void *temp_mmio;
106
107 module_info = (struct acpi_prmt_module_info *) header;
108 module_info_size = struct_size(tm, handlers, module_info->handler_info_count);
109 tm = kmalloc(module_info_size, GFP_KERNEL);
110 if (!tm)
111 goto parse_prmt_out1;
112
113 guid_copy(&tm->guid, (guid_t *) module_info->module_guid);
114 tm->major_rev = module_info->major_rev;
115 tm->minor_rev = module_info->minor_rev;
116 tm->handler_count = module_info->handler_info_count;
117 tm->updatable = true;
118
119 if (module_info->mmio_list_pointer) {
120 /*
121 * Each module is associated with a list of addr
122 * ranges that it can use during the service
123 */
124 mmio_count = (u64 *) memremap(module_info->mmio_list_pointer, 8, MEMREMAP_WB);
125 if (!mmio_count)
126 goto parse_prmt_out2;
127
128 mmio_range_size = struct_size(tm->mmio_info, addr_ranges, *mmio_count);
129 tm->mmio_info = kmalloc(mmio_range_size, GFP_KERNEL);
130 if (!tm->mmio_info)
131 goto parse_prmt_out3;
132
133 temp_mmio = memremap(module_info->mmio_list_pointer, mmio_range_size, MEMREMAP_WB);
134 if (!temp_mmio)
135 goto parse_prmt_out4;
136 memmove(tm->mmio_info, temp_mmio, mmio_range_size);
137 } else {
138 tm->mmio_info = kmalloc(sizeof(*tm->mmio_info), GFP_KERNEL);
139 if (!tm->mmio_info)
140 goto parse_prmt_out2;
141
142 tm->mmio_info->mmio_count = 0;
143 }
144
145 INIT_LIST_HEAD(&tm->module_list);
146 list_add(&tm->module_list, &prm_module_list);
147
148 handler_info = get_first_handler(module_info);
149 do {
150 th = &tm->handlers[cur_handler];
151
152 guid_copy(&th->guid, (guid_t *)handler_info->handler_guid);
153 th->handler_addr =
154 (void *)efi_pa_va_lookup(&th->guid, handler_info->handler_address);
155 /*
156 * Print a warning message if handler_addr is zero which is not expected to
157 * ever happen.
158 */
159 if (unlikely(!th->handler_addr))
160 pr_warn("Failed to find VA of handler for GUID: %pUL, PA: 0x%llx",
161 &th->guid, handler_info->handler_address);
162
163 th->static_data_buffer_addr =
164 efi_pa_va_lookup(&th->guid, handler_info->static_data_buffer_address);
165 /*
166 * According to the PRM specification, static_data_buffer_address can be zero,
167 * so avoid printing a warning message in that case. Otherwise, if the
168 * return value of efi_pa_va_lookup() is zero, print the message.
169 */
170 if (unlikely(!th->static_data_buffer_addr && handler_info->static_data_buffer_address))
171 pr_warn("Failed to find VA of static data buffer for GUID: %pUL, PA: 0x%llx",
172 &th->guid, handler_info->static_data_buffer_address);
173
174 th->acpi_param_buffer_addr =
175 efi_pa_va_lookup(&th->guid, handler_info->acpi_param_buffer_address);
176
177 /*
178 * According to the PRM specification, acpi_param_buffer_address can be zero,
179 * so avoid printing a warning message in that case. Otherwise, if the
180 * return value of efi_pa_va_lookup() is zero, print the message.
181 */
182 if (unlikely(!th->acpi_param_buffer_addr && handler_info->acpi_param_buffer_address))
183 pr_warn("Failed to find VA of acpi param buffer for GUID: %pUL, PA: 0x%llx",
184 &th->guid, handler_info->acpi_param_buffer_address);
185
186 } while (++cur_handler < tm->handler_count && (handler_info = get_next_handler(handler_info)));
187
188 return 0;
189
190 parse_prmt_out4:
191 kfree(tm->mmio_info);
192 parse_prmt_out3:
193 memunmap(mmio_count);
194 parse_prmt_out2:
195 kfree(tm);
196 parse_prmt_out1:
197 return -ENOMEM;
198 }
199
200 #define GET_MODULE 0
201 #define GET_HANDLER 1
202
find_guid_info(const guid_t * guid,u8 mode)203 static void *find_guid_info(const guid_t *guid, u8 mode)
204 {
205 struct prm_handler_info *cur_handler;
206 struct prm_module_info *cur_module;
207 int i = 0;
208
209 list_for_each_entry(cur_module, &prm_module_list, module_list) {
210 for (i = 0; i < cur_module->handler_count; ++i) {
211 cur_handler = &cur_module->handlers[i];
212 if (guid_equal(guid, &cur_handler->guid)) {
213 if (mode == GET_MODULE)
214 return (void *)cur_module;
215 else
216 return (void *)cur_handler;
217 }
218 }
219 }
220
221 return NULL;
222 }
223
find_prm_module(const guid_t * guid)224 static struct prm_module_info *find_prm_module(const guid_t *guid)
225 {
226 return (struct prm_module_info *)find_guid_info(guid, GET_MODULE);
227 }
228
find_prm_handler(const guid_t * guid)229 static struct prm_handler_info *find_prm_handler(const guid_t *guid)
230 {
231 return (struct prm_handler_info *) find_guid_info(guid, GET_HANDLER);
232 }
233
234 /* In-coming PRM commands */
235
236 #define PRM_CMD_RUN_SERVICE 0
237 #define PRM_CMD_START_TRANSACTION 1
238 #define PRM_CMD_END_TRANSACTION 2
239
240 /* statuses that can be passed back to ASL */
241
242 #define PRM_HANDLER_SUCCESS 0
243 #define PRM_HANDLER_ERROR 1
244 #define INVALID_PRM_COMMAND 2
245 #define PRM_HANDLER_GUID_NOT_FOUND 3
246 #define UPDATE_LOCK_ALREADY_HELD 4
247 #define UPDATE_UNLOCK_WITHOUT_LOCK 5
248
acpi_call_prm_handler(guid_t handler_guid,void * param_buffer)249 int acpi_call_prm_handler(guid_t handler_guid, void *param_buffer)
250 {
251 struct prm_handler_info *handler = find_prm_handler(&handler_guid);
252 struct prm_module_info *module = find_prm_module(&handler_guid);
253 struct prm_context_buffer context;
254 efi_status_t status;
255
256 if (!module || !handler)
257 return -ENODEV;
258
259 memset(&context, 0, sizeof(context));
260 ACPI_COPY_NAMESEG(context.signature, "PRMC");
261 context.identifier = handler->guid;
262 context.static_data_buffer = handler->static_data_buffer_addr;
263 context.mmio_ranges = module->mmio_info;
264
265 status = efi_call_acpi_prm_handler(handler->handler_addr,
266 (u64)param_buffer,
267 &context);
268
269 return efi_status_to_err(status);
270 }
271 EXPORT_SYMBOL_GPL(acpi_call_prm_handler);
272
273 /*
274 * This is the PlatformRtMechanism opregion space handler.
275 * @function: indicates the read/write. In fact as the PlatformRtMechanism
276 * message is driven by command, only write is meaningful.
277 *
278 * @addr : not used
279 * @bits : not used.
280 * @value : it is an in/out parameter. It points to the PRM message buffer.
281 * @handler_context: not used
282 */
acpi_platformrt_space_handler(u32 function,acpi_physical_address addr,u32 bits,acpi_integer * value,void * handler_context,void * region_context)283 static acpi_status acpi_platformrt_space_handler(u32 function,
284 acpi_physical_address addr,
285 u32 bits, acpi_integer *value,
286 void *handler_context,
287 void *region_context)
288 {
289 struct prm_buffer *buffer = ACPI_CAST_PTR(struct prm_buffer, value);
290 struct prm_handler_info *handler;
291 struct prm_module_info *module;
292 efi_status_t status;
293 struct prm_context_buffer context;
294
295 if (!efi_enabled(EFI_RUNTIME_SERVICES)) {
296 pr_err_ratelimited("PRM: EFI runtime services no longer available\n");
297 return AE_NO_HANDLER;
298 }
299
300 /*
301 * The returned acpi_status will always be AE_OK. Error values will be
302 * saved in the first byte of the PRM message buffer to be used by ASL.
303 */
304 switch (buffer->prm_cmd) {
305 case PRM_CMD_RUN_SERVICE:
306
307 handler = find_prm_handler(&buffer->handler_guid);
308 module = find_prm_module(&buffer->handler_guid);
309 if (!handler || !module)
310 goto invalid_guid;
311
312 if (!handler->handler_addr) {
313 buffer->prm_status = PRM_HANDLER_ERROR;
314 return AE_OK;
315 }
316
317 ACPI_COPY_NAMESEG(context.signature, "PRMC");
318 context.revision = 0x0;
319 context.reserved = 0x0;
320 context.identifier = handler->guid;
321 context.static_data_buffer = handler->static_data_buffer_addr;
322 context.mmio_ranges = module->mmio_info;
323
324 status = efi_call_acpi_prm_handler(handler->handler_addr,
325 handler->acpi_param_buffer_addr,
326 &context);
327 if (status == EFI_SUCCESS) {
328 buffer->prm_status = PRM_HANDLER_SUCCESS;
329 } else {
330 buffer->prm_status = PRM_HANDLER_ERROR;
331 buffer->efi_status = status;
332 }
333 break;
334
335 case PRM_CMD_START_TRANSACTION:
336
337 module = find_prm_module(&buffer->handler_guid);
338 if (!module)
339 goto invalid_guid;
340
341 if (module->updatable)
342 module->updatable = false;
343 else
344 buffer->prm_status = UPDATE_LOCK_ALREADY_HELD;
345 break;
346
347 case PRM_CMD_END_TRANSACTION:
348
349 module = find_prm_module(&buffer->handler_guid);
350 if (!module)
351 goto invalid_guid;
352
353 if (module->updatable)
354 buffer->prm_status = UPDATE_UNLOCK_WITHOUT_LOCK;
355 else
356 module->updatable = true;
357 break;
358
359 default:
360
361 buffer->prm_status = INVALID_PRM_COMMAND;
362 break;
363 }
364
365 return AE_OK;
366
367 invalid_guid:
368 buffer->prm_status = PRM_HANDLER_GUID_NOT_FOUND;
369 return AE_OK;
370 }
371
init_prmt(void)372 void __init init_prmt(void)
373 {
374 struct acpi_table_header *tbl;
375 acpi_status status;
376 int mc;
377
378 status = acpi_get_table(ACPI_SIG_PRMT, 0, &tbl);
379 if (ACPI_FAILURE(status))
380 return;
381
382 mc = acpi_table_parse_entries(ACPI_SIG_PRMT, sizeof(struct acpi_table_prmt) +
383 sizeof (struct acpi_table_prmt_header),
384 0, acpi_parse_prmt, 0);
385 acpi_put_table(tbl);
386 /*
387 * Return immediately if PRMT table is not present or no PRM module found.
388 */
389 if (mc <= 0)
390 return;
391
392 pr_info("PRM: found %u modules\n", mc);
393
394 if (!efi_enabled(EFI_RUNTIME_SERVICES)) {
395 pr_err("PRM: EFI runtime services unavailable\n");
396 return;
397 }
398
399 status = acpi_install_address_space_handler(ACPI_ROOT_OBJECT,
400 ACPI_ADR_SPACE_PLATFORM_RT,
401 &acpi_platformrt_space_handler,
402 NULL, NULL);
403 if (ACPI_FAILURE(status))
404 pr_alert("PRM: OperationRegion handler could not be installed\n");
405 }
406