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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
52
53static LIST_HEAD(prm_module_list);
54
55struct prm_handler_info {
56 guid_t guid;
57 u64 handler_addr;
58 u64 static_data_buffer_addr;
59 u64 acpi_param_buffer_addr;
60
61 struct list_head handler_list;
62};
63
64struct prm_module_info {
65 guid_t guid;
66 u16 major_rev;
67 u16 minor_rev;
68 u16 handler_count;
69 struct prm_mmio_info *mmio_info;
70 bool updatable;
71
72 struct list_head module_list;
73 struct prm_handler_info handlers[];
74};
75
76
77static u64 efi_pa_va_lookup(u64 pa)
78{
79 efi_memory_desc_t *md;
80 u64 pa_offset = pa & ~PAGE_MASK;
81 u64 page = pa & PAGE_MASK;
82
83 for_each_efi_memory_desc(md) {
84 if (md->phys_addr < pa && pa < md->phys_addr + PAGE_SIZE * md->num_pages)
85 return pa_offset + md->virt_addr + page - md->phys_addr;
86 }
87
88 return 0;
89}
90
91
92#define get_first_handler(a) ((struct acpi_prmt_handler_info *) ((char *) (a) + a->handler_info_offset))
93#define get_next_handler(a) ((struct acpi_prmt_handler_info *) (sizeof(struct acpi_prmt_handler_info) + (char *) a))
94
95static int __init
96acpi_parse_prmt(union acpi_subtable_headers *header, const unsigned long end)
97{
98 struct acpi_prmt_module_info *module_info;
99 struct acpi_prmt_handler_info *handler_info;
100 struct prm_handler_info *th;
101 struct prm_module_info *tm;
102 u64 mmio_count = 0;
103 u64 cur_handler = 0;
104 u32 module_info_size = 0;
105 u64 mmio_range_size = 0;
106 void *temp_mmio;
107
108 module_info = (struct acpi_prmt_module_info *) header;
109 module_info_size = struct_size(tm, handlers, module_info->handler_info_count);
110 tm = kmalloc(module_info_size, GFP_KERNEL);
111
112 guid_copy(&tm->guid, (guid_t *) module_info->module_guid);
113 tm->major_rev = module_info->major_rev;
114 tm->minor_rev = module_info->minor_rev;
115 tm->handler_count = module_info->handler_info_count;
116 tm->updatable = true;
117
118 if (module_info->mmio_list_pointer) {
119 /*
120 * Each module is associated with a list of addr
121 * ranges that it can use during the service
122 */
123 mmio_count = *(u64 *) memremap(module_info->mmio_list_pointer, 8, MEMREMAP_WB);
124 mmio_range_size = struct_size(tm->mmio_info, addr_ranges, mmio_count);
125 tm->mmio_info = kmalloc(mmio_range_size, GFP_KERNEL);
126 temp_mmio = memremap(module_info->mmio_list_pointer, mmio_range_size, MEMREMAP_WB);
127 memmove(tm->mmio_info, temp_mmio, mmio_range_size);
128 } else {
129 mmio_range_size = struct_size(tm->mmio_info, addr_ranges, mmio_count);
130 tm->mmio_info = kmalloc(mmio_range_size, GFP_KERNEL);
131 tm->mmio_info->mmio_count = 0;
132 }
133
134 INIT_LIST_HEAD(&tm->module_list);
135 list_add(&tm->module_list, &prm_module_list);
136
137 handler_info = get_first_handler(module_info);
138 do {
139 th = &tm->handlers[cur_handler];
140
141 guid_copy(&th->guid, (guid_t *)handler_info->handler_guid);
142 th->handler_addr = efi_pa_va_lookup(handler_info->handler_address);
143 th->static_data_buffer_addr = efi_pa_va_lookup(handler_info->static_data_buffer_address);
144 th->acpi_param_buffer_addr = efi_pa_va_lookup(handler_info->acpi_param_buffer_address);
145 } while (++cur_handler < tm->handler_count && (handler_info = get_next_handler(handler_info)));
146
147 return 0;
148}
149
150#define GET_MODULE 0
151#define GET_HANDLER 1
152
153static void *find_guid_info(const guid_t *guid, u8 mode)
154{
155 struct prm_handler_info *cur_handler;
156 struct prm_module_info *cur_module;
157 int i = 0;
158
159 list_for_each_entry(cur_module, &prm_module_list, module_list) {
160 for (i = 0; i < cur_module->handler_count; ++i) {
161 cur_handler = &cur_module->handlers[i];
162 if (guid_equal(guid, &cur_handler->guid)) {
163 if (mode == GET_MODULE)
164 return (void *)cur_module;
165 else
166 return (void *)cur_handler;
167 }
168 }
169 }
170
171 return NULL;
172}
173
174
175static struct prm_module_info *find_prm_module(const guid_t *guid)
176{
177 return (struct prm_module_info *)find_guid_info(guid, GET_MODULE);
178}
179
180static struct prm_handler_info *find_prm_handler(const guid_t *guid)
181{
182 return (struct prm_handler_info *) find_guid_info(guid, GET_HANDLER);
183}
184
185/* In-coming PRM commands */
186
187#define PRM_CMD_RUN_SERVICE 0
188#define PRM_CMD_START_TRANSACTION 1
189#define PRM_CMD_END_TRANSACTION 2
190
191/* statuses that can be passed back to ASL */
192
193#define PRM_HANDLER_SUCCESS 0
194#define PRM_HANDLER_ERROR 1
195#define INVALID_PRM_COMMAND 2
196#define PRM_HANDLER_GUID_NOT_FOUND 3
197#define UPDATE_LOCK_ALREADY_HELD 4
198#define UPDATE_UNLOCK_WITHOUT_LOCK 5
199
200/*
201 * This is the PlatformRtMechanism opregion space handler.
202 * @function: indicates the read/write. In fact as the PlatformRtMechanism
203 * message is driven by command, only write is meaningful.
204 *
205 * @addr : not used
206 * @bits : not used.
207 * @value : it is an in/out parameter. It points to the PRM message buffer.
208 * @handler_context: not used
209 */
210static acpi_status acpi_platformrt_space_handler(u32 function,
211 acpi_physical_address addr,
212 u32 bits, acpi_integer *value,
213 void *handler_context,
214 void *region_context)
215{
216 struct prm_buffer *buffer = ACPI_CAST_PTR(struct prm_buffer, value);
217 struct prm_handler_info *handler;
218 struct prm_module_info *module;
219 efi_status_t status;
220 struct prm_context_buffer context;
221
222 /*
223 * The returned acpi_status will always be AE_OK. Error values will be
224 * saved in the first byte of the PRM message buffer to be used by ASL.
225 */
226 switch (buffer->prm_cmd) {
227 case PRM_CMD_RUN_SERVICE:
228
229 handler = find_prm_handler(&buffer->handler_guid);
230 module = find_prm_module(&buffer->handler_guid);
231 if (!handler || !module)
232 goto invalid_guid;
233
234 ACPI_COPY_NAMESEG(context.signature, "PRMC");
235 context.revision = 0x0;
236 context.reserved = 0x0;
237 context.identifier = handler->guid;
238 context.static_data_buffer = handler->static_data_buffer_addr;
239 context.mmio_ranges = module->mmio_info;
240
241 status = efi_call_virt_pointer(handler, handler_addr,
242 handler->acpi_param_buffer_addr,
243 &context);
244 if (status == EFI_SUCCESS) {
245 buffer->prm_status = PRM_HANDLER_SUCCESS;
246 } else {
247 buffer->prm_status = PRM_HANDLER_ERROR;
248 buffer->efi_status = status;
249 }
250 break;
251
252 case PRM_CMD_START_TRANSACTION:
253
254 module = find_prm_module(&buffer->handler_guid);
255 if (!module)
256 goto invalid_guid;
257
258 if (module->updatable)
259 module->updatable = false;
260 else
261 buffer->prm_status = UPDATE_LOCK_ALREADY_HELD;
262 break;
263
264 case PRM_CMD_END_TRANSACTION:
265
266 module = find_prm_module(&buffer->handler_guid);
267 if (!module)
268 goto invalid_guid;
269
270 if (module->updatable)
271 buffer->prm_status = UPDATE_UNLOCK_WITHOUT_LOCK;
272 else
273 module->updatable = true;
274 break;
275
276 default:
277
278 buffer->prm_status = INVALID_PRM_COMMAND;
279 break;
280 }
281
282 return AE_OK;
283
284invalid_guid:
285 buffer->prm_status = PRM_HANDLER_GUID_NOT_FOUND;
286 return AE_OK;
287}
288
289void __init init_prmt(void)
290{
291 struct acpi_table_header *tbl;
292 acpi_status status;
293 int mc;
294
295 status = acpi_get_table(ACPI_SIG_PRMT, 0, &tbl);
296 if (ACPI_FAILURE(status))
297 return;
298
299 mc = acpi_table_parse_entries(ACPI_SIG_PRMT, sizeof(struct acpi_table_prmt) +
300 sizeof (struct acpi_table_prmt_header),
301 0, acpi_parse_prmt, 0);
302 acpi_put_table(tbl);
303 /*
304 * Return immediately if PRMT table is not present or no PRM module found.
305 */
306 if (mc <= 0)
307 return;
308
309 pr_info("PRM: found %u modules\n", mc);
310
311 status = acpi_install_address_space_handler(ACPI_ROOT_OBJECT,
312 ACPI_ADR_SPACE_PLATFORM_RT,
313 &acpi_platformrt_space_handler,
314 NULL, NULL);
315 if (ACPI_FAILURE(status))
316 pr_alert("PRM: OperationRegion handler could not be installed\n");
317}