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)
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 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(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
92static int __init
93acpi_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(size: module_info_size, GFP_KERNEL);
108 if (!tm)
109 goto parse_prmt_out1;
110
111 guid_copy(dst: &tm->guid, src: (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(offset: module_info->mmio_list_pointer, size: 8, flags: 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(size: mmio_range_size, GFP_KERNEL);
128 if (!tm->mmio_info)
129 goto parse_prmt_out3;
130
131 temp_mmio = memremap(offset: module_info->mmio_list_pointer, size: mmio_range_size, flags: 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(size: 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(list: &tm->module_list);
144 list_add(new: &tm->module_list, head: &prm_module_list);
145
146 handler_info = get_first_handler(module_info);
147 do {
148 th = &tm->handlers[cur_handler];
149
150 guid_copy(dst: &th->guid, src: (guid_t *)handler_info->handler_guid);
151 th->handler_addr = (void *)efi_pa_va_lookup(pa: handler_info->handler_address);
152 th->static_data_buffer_addr = efi_pa_va_lookup(pa: handler_info->static_data_buffer_address);
153 th->acpi_param_buffer_addr = efi_pa_va_lookup(pa: 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
158parse_prmt_out4:
159 kfree(objp: tm->mmio_info);
160parse_prmt_out3:
161 memunmap(addr: mmio_count);
162parse_prmt_out2:
163 kfree(objp: tm);
164parse_prmt_out1:
165 return -ENOMEM;
166}
167
168#define GET_MODULE 0
169#define GET_HANDLER 1
170
171static 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(u1: guid, u2: &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
192static 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
197static 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 */
227static 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(guid: &buffer->handler_guid);
252 module = find_prm_module(guid: &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_addr: handler->handler_addr,
264 param_buffer_addr: handler->acpi_param_buffer_addr,
265 context: &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(guid: &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(guid: &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
306invalid_guid:
307 buffer->prm_status = PRM_HANDLER_GUID_NOT_FOUND;
308 return AE_OK;
309}
310
311void __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, instance: 0, out_table: &tbl);
318 if (ACPI_FAILURE(status))
319 return;
320
321 mc = acpi_table_parse_entries(ACPI_SIG_PRMT, table_size: sizeof(struct acpi_table_prmt) +
322 sizeof (struct acpi_table_prmt_header),
323 entry_id: 0, handler: acpi_parse_prmt, max_entries: 0);
324 acpi_put_table(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 handler: &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

source code of linux/drivers/acpi/prmt.c