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 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
efi_pa_va_lookup(u64 pa)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
acpi_parse_prmt(union acpi_subtable_headers * header,const unsigned long end)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 = 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
find_guid_info(const guid_t * guid,u8 mode)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
find_prm_module(const guid_t * guid)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
find_prm_handler(const guid_t * guid)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 */
acpi_platformrt_space_handler(u32 function,acpi_physical_address addr,u32 bits,acpi_integer * value,void * handler_context,void * region_context)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 /*
240 * The returned acpi_status will always be AE_OK. Error values will be
241 * saved in the first byte of the PRM message buffer to be used by ASL.
242 */
243 switch (buffer->prm_cmd) {
244 case PRM_CMD_RUN_SERVICE:
245
246 handler = find_prm_handler(&buffer->handler_guid);
247 module = find_prm_module(&buffer->handler_guid);
248 if (!handler || !module)
249 goto invalid_guid;
250
251 ACPI_COPY_NAMESEG(context.signature, "PRMC");
252 context.revision = 0x0;
253 context.reserved = 0x0;
254 context.identifier = handler->guid;
255 context.static_data_buffer = handler->static_data_buffer_addr;
256 context.mmio_ranges = module->mmio_info;
257
258 status = efi_call_virt_pointer(handler, handler_addr,
259 handler->acpi_param_buffer_addr,
260 &context);
261 if (status == EFI_SUCCESS) {
262 buffer->prm_status = PRM_HANDLER_SUCCESS;
263 } else {
264 buffer->prm_status = PRM_HANDLER_ERROR;
265 buffer->efi_status = status;
266 }
267 break;
268
269 case PRM_CMD_START_TRANSACTION:
270
271 module = find_prm_module(&buffer->handler_guid);
272 if (!module)
273 goto invalid_guid;
274
275 if (module->updatable)
276 module->updatable = false;
277 else
278 buffer->prm_status = UPDATE_LOCK_ALREADY_HELD;
279 break;
280
281 case PRM_CMD_END_TRANSACTION:
282
283 module = find_prm_module(&buffer->handler_guid);
284 if (!module)
285 goto invalid_guid;
286
287 if (module->updatable)
288 buffer->prm_status = UPDATE_UNLOCK_WITHOUT_LOCK;
289 else
290 module->updatable = true;
291 break;
292
293 default:
294
295 buffer->prm_status = INVALID_PRM_COMMAND;
296 break;
297 }
298
299 return AE_OK;
300
301 invalid_guid:
302 buffer->prm_status = PRM_HANDLER_GUID_NOT_FOUND;
303 return AE_OK;
304 }
305
init_prmt(void)306 void __init init_prmt(void)
307 {
308 struct acpi_table_header *tbl;
309 acpi_status status;
310 int mc;
311
312 status = acpi_get_table(ACPI_SIG_PRMT, 0, &tbl);
313 if (ACPI_FAILURE(status))
314 return;
315
316 mc = acpi_table_parse_entries(ACPI_SIG_PRMT, sizeof(struct acpi_table_prmt) +
317 sizeof (struct acpi_table_prmt_header),
318 0, acpi_parse_prmt, 0);
319 acpi_put_table(tbl);
320 /*
321 * Return immediately if PRMT table is not present or no PRM module found.
322 */
323 if (mc <= 0)
324 return;
325
326 pr_info("PRM: found %u modules\n", mc);
327
328 status = acpi_install_address_space_handler(ACPI_ROOT_OBJECT,
329 ACPI_ADR_SPACE_PLATFORM_RT,
330 &acpi_platformrt_space_handler,
331 NULL, NULL);
332 if (ACPI_FAILURE(status))
333 pr_alert("PRM: OperationRegion handler could not be installed\n");
334 }
335