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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)
24struct prm_mmio_addr_range {
25 u64 phys_addr;
26 u64 virt_addr;
27 u32 length;
28};
29
30struct prm_mmio_info {
31 u64 mmio_count;
32 struct prm_mmio_addr_range addr_ranges[];
33};
34
35struct prm_buffer {
36 u8 prm_status;
37 u64 efi_status;
38 u8 prm_cmd;
39 guid_t handler_guid;
40};
41
42struct 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
52static LIST_HEAD(prm_module_list);
53
54struct 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
63struct 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
75static 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
94static int __init
95acpi_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_obj(*tm->mmio_info);
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
154 /*
155 * Print an error message if handler_address is NULL, the parse of VA also
156 * can be skipped.
157 */
158 if (unlikely(!handler_info->handler_address)) {
159 pr_info("Skipping handler with NULL address for GUID: %pUL",
160 (guid_t *)handler_info->handler_guid);
161 continue;
162 }
163
164 th->handler_addr =
165 (void *)efi_pa_va_lookup(&th->guid, handler_info->handler_address);
166 /*
167 * Print a warning message and skip the parse of VA if handler_addr is zero
168 * which is not expected to ever happen.
169 */
170 if (unlikely(!th->handler_addr)) {
171 pr_warn("Failed to find VA of handler for GUID: %pUL, PA: 0x%llx",
172 &th->guid, handler_info->handler_address);
173 continue;
174 }
175
176 th->static_data_buffer_addr =
177 efi_pa_va_lookup(&th->guid, handler_info->static_data_buffer_address);
178 /*
179 * According to the PRM specification, static_data_buffer_address can be zero,
180 * so avoid printing a warning message in that case. Otherwise, if the
181 * return value of efi_pa_va_lookup() is zero, print the message.
182 */
183 if (unlikely(!th->static_data_buffer_addr && handler_info->static_data_buffer_address))
184 pr_warn("Failed to find VA of static data buffer for GUID: %pUL, PA: 0x%llx",
185 &th->guid, handler_info->static_data_buffer_address);
186
187 th->acpi_param_buffer_addr =
188 efi_pa_va_lookup(&th->guid, handler_info->acpi_param_buffer_address);
189
190 /*
191 * According to the PRM specification, acpi_param_buffer_address can be zero,
192 * so avoid printing a warning message in that case. Otherwise, if the
193 * return value of efi_pa_va_lookup() is zero, print the message.
194 */
195 if (unlikely(!th->acpi_param_buffer_addr && handler_info->acpi_param_buffer_address))
196 pr_warn("Failed to find VA of acpi param buffer for GUID: %pUL, PA: 0x%llx",
197 &th->guid, handler_info->acpi_param_buffer_address);
198
199 } while (++cur_handler < tm->handler_count && (handler_info = get_next_handler(handler_info)));
200
201 return 0;
202
203parse_prmt_out4:
204 kfree(tm->mmio_info);
205parse_prmt_out3:
206 memunmap(mmio_count);
207parse_prmt_out2:
208 kfree(tm);
209parse_prmt_out1:
210 return -ENOMEM;
211}
212
213#define GET_MODULE 0
214#define GET_HANDLER 1
215
216static void *find_guid_info(const guid_t *guid, u8 mode)
217{
218 struct prm_handler_info *cur_handler;
219 struct prm_module_info *cur_module;
220 int i = 0;
221
222 list_for_each_entry(cur_module, &prm_module_list, module_list) {
223 for (i = 0; i < cur_module->handler_count; ++i) {
224 cur_handler = &cur_module->handlers[i];
225 if (guid_equal(guid, &cur_handler->guid)) {
226 if (mode == GET_MODULE)
227 return (void *)cur_module;
228 else
229 return (void *)cur_handler;
230 }
231 }
232 }
233
234 return NULL;
235}
236
237static struct prm_module_info *find_prm_module(const guid_t *guid)
238{
239 return (struct prm_module_info *)find_guid_info(guid, GET_MODULE);
240}
241
242static struct prm_handler_info *find_prm_handler(const guid_t *guid)
243{
244 return (struct prm_handler_info *) find_guid_info(guid, GET_HANDLER);
245}
246
247bool acpi_prm_handler_available(const guid_t *guid)
248{
249 return find_prm_handler(guid) && find_prm_module(guid);
250}
251EXPORT_SYMBOL_GPL(acpi_prm_handler_available);
252
253/* In-coming PRM commands */
254
255#define PRM_CMD_RUN_SERVICE 0
256#define PRM_CMD_START_TRANSACTION 1
257#define PRM_CMD_END_TRANSACTION 2
258
259/* statuses that can be passed back to ASL */
260
261#define PRM_HANDLER_SUCCESS 0
262#define PRM_HANDLER_ERROR 1
263#define INVALID_PRM_COMMAND 2
264#define PRM_HANDLER_GUID_NOT_FOUND 3
265#define UPDATE_LOCK_ALREADY_HELD 4
266#define UPDATE_UNLOCK_WITHOUT_LOCK 5
267
268int acpi_call_prm_handler(guid_t handler_guid, void *param_buffer)
269{
270 struct prm_handler_info *handler = find_prm_handler(&handler_guid);
271 struct prm_module_info *module = find_prm_module(&handler_guid);
272 struct prm_context_buffer context;
273 efi_status_t status;
274
275 if (!module || !handler)
276 return -ENODEV;
277
278 memset(&context, 0, sizeof(context));
279 ACPI_COPY_NAMESEG(context.signature, "PRMC");
280 context.identifier = handler->guid;
281 context.static_data_buffer = handler->static_data_buffer_addr;
282 context.mmio_ranges = module->mmio_info;
283
284 status = efi_call_acpi_prm_handler(handler->handler_addr,
285 (u64)param_buffer,
286 &context);
287
288 return efi_status_to_err(status);
289}
290EXPORT_SYMBOL_GPL(acpi_call_prm_handler);
291
292/*
293 * This is the PlatformRtMechanism opregion space handler.
294 * @function: indicates the read/write. In fact as the PlatformRtMechanism
295 * message is driven by command, only write is meaningful.
296 *
297 * @addr : not used
298 * @bits : not used.
299 * @value : it is an in/out parameter. It points to the PRM message buffer.
300 * @handler_context: not used
301 */
302static acpi_status acpi_platformrt_space_handler(u32 function,
303 acpi_physical_address addr,
304 u32 bits, acpi_integer *value,
305 void *handler_context,
306 void *region_context)
307{
308 struct prm_buffer *buffer = ACPI_CAST_PTR(struct prm_buffer, value);
309 struct prm_handler_info *handler;
310 struct prm_module_info *module;
311 efi_status_t status;
312 struct prm_context_buffer context;
313
314 if (!efi_enabled(EFI_RUNTIME_SERVICES)) {
315 pr_err_ratelimited("PRM: EFI runtime services no longer available\n");
316 return AE_NO_HANDLER;
317 }
318
319 /*
320 * The returned acpi_status will always be AE_OK. Error values will be
321 * saved in the first byte of the PRM message buffer to be used by ASL.
322 */
323 switch (buffer->prm_cmd) {
324 case PRM_CMD_RUN_SERVICE:
325
326 handler = find_prm_handler(&buffer->handler_guid);
327 module = find_prm_module(&buffer->handler_guid);
328 if (!handler || !module)
329 goto invalid_guid;
330
331 if (!handler->handler_addr) {
332 buffer->prm_status = PRM_HANDLER_ERROR;
333 return AE_OK;
334 }
335
336 ACPI_COPY_NAMESEG(context.signature, "PRMC");
337 context.revision = 0x0;
338 context.reserved = 0x0;
339 context.identifier = handler->guid;
340 context.static_data_buffer = handler->static_data_buffer_addr;
341 context.mmio_ranges = module->mmio_info;
342
343 status = efi_call_acpi_prm_handler(handler->handler_addr,
344 handler->acpi_param_buffer_addr,
345 &context);
346 if (status == EFI_SUCCESS) {
347 buffer->prm_status = PRM_HANDLER_SUCCESS;
348 } else {
349 buffer->prm_status = PRM_HANDLER_ERROR;
350 buffer->efi_status = status;
351 }
352 break;
353
354 case PRM_CMD_START_TRANSACTION:
355
356 module = find_prm_module(&buffer->handler_guid);
357 if (!module)
358 goto invalid_guid;
359
360 if (module->updatable)
361 module->updatable = false;
362 else
363 buffer->prm_status = UPDATE_LOCK_ALREADY_HELD;
364 break;
365
366 case PRM_CMD_END_TRANSACTION:
367
368 module = find_prm_module(&buffer->handler_guid);
369 if (!module)
370 goto invalid_guid;
371
372 if (module->updatable)
373 buffer->prm_status = UPDATE_UNLOCK_WITHOUT_LOCK;
374 else
375 module->updatable = true;
376 break;
377
378 default:
379
380 buffer->prm_status = INVALID_PRM_COMMAND;
381 break;
382 }
383
384 return AE_OK;
385
386invalid_guid:
387 buffer->prm_status = PRM_HANDLER_GUID_NOT_FOUND;
388 return AE_OK;
389}
390
391void __init init_prmt(void)
392{
393 struct acpi_table_header *tbl;
394 acpi_status status;
395 int mc;
396
397 status = acpi_get_table(ACPI_SIG_PRMT, 0, &tbl);
398 if (ACPI_FAILURE(status))
399 return;
400
401 mc = acpi_table_parse_entries(ACPI_SIG_PRMT, sizeof(struct acpi_table_prmt) +
402 sizeof (struct acpi_table_prmt_header),
403 0, acpi_parse_prmt, 0);
404 acpi_put_table(tbl);
405 /*
406 * Return immediately if PRMT table is not present or no PRM module found.
407 */
408 if (mc <= 0)
409 return;
410
411 pr_info("PRM: found %u modules\n", mc);
412
413 if (!efi_enabled(EFI_RUNTIME_SERVICES)) {
414 pr_err("PRM: EFI runtime services unavailable\n");
415 return;
416 }
417
418 status = acpi_install_address_space_handler(ACPI_ROOT_OBJECT,
419 ACPI_ADR_SPACE_PLATFORM_RT,
420 &acpi_platformrt_space_handler,
421 NULL, NULL);
422 if (ACPI_FAILURE(status))
423 pr_alert("PRM: OperationRegion handler could not be installed\n");
424}