1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * FDT related Helper functions used by the EFI stub on multiple
4 * architectures. This should be #included by the EFI stub
5 * implementation files.
6 *
7 * Copyright 2013 Linaro Limited; author Roy Franz
8 */
9
10 #include <linux/efi.h>
11 #include <linux/libfdt.h>
12 #include <asm/efi.h>
13
14 #include "efistub.h"
15
16 #define EFI_DT_ADDR_CELLS_DEFAULT 2
17 #define EFI_DT_SIZE_CELLS_DEFAULT 2
18
fdt_update_cell_size(void * fdt)19 static void fdt_update_cell_size(void *fdt)
20 {
21 int offset;
22
23 offset = fdt_path_offset(fdt, "/");
24 /* Set the #address-cells and #size-cells values for an empty tree */
25
26 fdt_setprop_u32(fdt, offset, "#address-cells", EFI_DT_ADDR_CELLS_DEFAULT);
27 fdt_setprop_u32(fdt, offset, "#size-cells", EFI_DT_SIZE_CELLS_DEFAULT);
28 }
29
update_fdt(void * orig_fdt,unsigned long orig_fdt_size,void * fdt,int new_fdt_size,char * cmdline_ptr,u64 initrd_addr,u64 initrd_size)30 static efi_status_t update_fdt(void *orig_fdt, unsigned long orig_fdt_size,
31 void *fdt, int new_fdt_size, char *cmdline_ptr,
32 u64 initrd_addr, u64 initrd_size)
33 {
34 int node, num_rsv;
35 int status;
36 u32 fdt_val32;
37 u64 fdt_val64;
38
39 /* Do some checks on provided FDT, if it exists: */
40 if (orig_fdt) {
41 if (fdt_check_header(orig_fdt)) {
42 efi_err("Device Tree header not valid!\n");
43 return EFI_LOAD_ERROR;
44 }
45 /*
46 * We don't get the size of the FDT if we get if from a
47 * configuration table:
48 */
49 if (orig_fdt_size && fdt_totalsize(orig_fdt) > orig_fdt_size) {
50 efi_err("Truncated device tree! foo!\n");
51 return EFI_LOAD_ERROR;
52 }
53 }
54
55 if (orig_fdt) {
56 status = fdt_open_into(orig_fdt, fdt, new_fdt_size);
57 } else {
58 status = fdt_create_empty_tree(fdt, new_fdt_size);
59 if (status == 0) {
60 /*
61 * Any failure from the following function is
62 * non-critical:
63 */
64 fdt_update_cell_size(fdt);
65 }
66 }
67
68 if (status != 0)
69 goto fdt_set_fail;
70
71 /*
72 * Delete all memory reserve map entries. When booting via UEFI,
73 * kernel will use the UEFI memory map to find reserved regions.
74 */
75 num_rsv = fdt_num_mem_rsv(fdt);
76 while (num_rsv-- > 0)
77 fdt_del_mem_rsv(fdt, num_rsv);
78
79 node = fdt_subnode_offset(fdt, 0, "chosen");
80 if (node < 0) {
81 node = fdt_add_subnode(fdt, 0, "chosen");
82 if (node < 0) {
83 /* 'node' is an error code when negative: */
84 status = node;
85 goto fdt_set_fail;
86 }
87 }
88
89 if (cmdline_ptr != NULL && strlen(cmdline_ptr) > 0) {
90 status = fdt_setprop(fdt, node, "bootargs", cmdline_ptr,
91 strlen(cmdline_ptr) + 1);
92 if (status)
93 goto fdt_set_fail;
94 }
95
96 /* Set initrd address/end in device tree, if present */
97 if (initrd_size != 0) {
98 u64 initrd_image_end;
99 u64 initrd_image_start = cpu_to_fdt64(initrd_addr);
100
101 status = fdt_setprop_var(fdt, node, "linux,initrd-start", initrd_image_start);
102 if (status)
103 goto fdt_set_fail;
104
105 initrd_image_end = cpu_to_fdt64(initrd_addr + initrd_size);
106 status = fdt_setprop_var(fdt, node, "linux,initrd-end", initrd_image_end);
107 if (status)
108 goto fdt_set_fail;
109 }
110
111 /* Add FDT entries for EFI runtime services in chosen node. */
112 node = fdt_subnode_offset(fdt, 0, "chosen");
113 fdt_val64 = cpu_to_fdt64((u64)(unsigned long)efi_system_table);
114
115 status = fdt_setprop_var(fdt, node, "linux,uefi-system-table", fdt_val64);
116 if (status)
117 goto fdt_set_fail;
118
119 fdt_val64 = U64_MAX; /* placeholder */
120
121 status = fdt_setprop_var(fdt, node, "linux,uefi-mmap-start", fdt_val64);
122 if (status)
123 goto fdt_set_fail;
124
125 fdt_val32 = U32_MAX; /* placeholder */
126
127 status = fdt_setprop_var(fdt, node, "linux,uefi-mmap-size", fdt_val32);
128 if (status)
129 goto fdt_set_fail;
130
131 status = fdt_setprop_var(fdt, node, "linux,uefi-mmap-desc-size", fdt_val32);
132 if (status)
133 goto fdt_set_fail;
134
135 status = fdt_setprop_var(fdt, node, "linux,uefi-mmap-desc-ver", fdt_val32);
136 if (status)
137 goto fdt_set_fail;
138
139 if (IS_ENABLED(CONFIG_RANDOMIZE_BASE) && !efi_nokaslr) {
140 efi_status_t efi_status;
141
142 efi_status = efi_get_random_bytes(sizeof(fdt_val64),
143 (u8 *)&fdt_val64);
144 if (efi_status == EFI_SUCCESS) {
145 status = fdt_setprop_var(fdt, node, "kaslr-seed", fdt_val64);
146 if (status)
147 goto fdt_set_fail;
148 }
149 }
150
151 /* Shrink the FDT back to its minimum size: */
152 fdt_pack(fdt);
153
154 return EFI_SUCCESS;
155
156 fdt_set_fail:
157 if (status == -FDT_ERR_NOSPACE)
158 return EFI_BUFFER_TOO_SMALL;
159
160 return EFI_LOAD_ERROR;
161 }
162
update_fdt_memmap(void * fdt,struct efi_boot_memmap * map)163 static efi_status_t update_fdt_memmap(void *fdt, struct efi_boot_memmap *map)
164 {
165 int node = fdt_path_offset(fdt, "/chosen");
166 u64 fdt_val64;
167 u32 fdt_val32;
168 int err;
169
170 if (node < 0)
171 return EFI_LOAD_ERROR;
172
173 fdt_val64 = cpu_to_fdt64((unsigned long)*map->map);
174
175 err = fdt_setprop_inplace_var(fdt, node, "linux,uefi-mmap-start", fdt_val64);
176 if (err)
177 return EFI_LOAD_ERROR;
178
179 fdt_val32 = cpu_to_fdt32(*map->map_size);
180
181 err = fdt_setprop_inplace_var(fdt, node, "linux,uefi-mmap-size", fdt_val32);
182 if (err)
183 return EFI_LOAD_ERROR;
184
185 fdt_val32 = cpu_to_fdt32(*map->desc_size);
186
187 err = fdt_setprop_inplace_var(fdt, node, "linux,uefi-mmap-desc-size", fdt_val32);
188 if (err)
189 return EFI_LOAD_ERROR;
190
191 fdt_val32 = cpu_to_fdt32(*map->desc_ver);
192
193 err = fdt_setprop_inplace_var(fdt, node, "linux,uefi-mmap-desc-ver", fdt_val32);
194 if (err)
195 return EFI_LOAD_ERROR;
196
197 return EFI_SUCCESS;
198 }
199
200 struct exit_boot_struct {
201 efi_memory_desc_t *runtime_map;
202 int *runtime_entry_count;
203 void *new_fdt_addr;
204 };
205
exit_boot_func(struct efi_boot_memmap * map,void * priv)206 static efi_status_t exit_boot_func(struct efi_boot_memmap *map,
207 void *priv)
208 {
209 struct exit_boot_struct *p = priv;
210 /*
211 * Update the memory map with virtual addresses. The function will also
212 * populate @runtime_map with copies of just the EFI_MEMORY_RUNTIME
213 * entries so that we can pass it straight to SetVirtualAddressMap()
214 */
215 efi_get_virtmap(*map->map, *map->map_size, *map->desc_size,
216 p->runtime_map, p->runtime_entry_count);
217
218 return update_fdt_memmap(p->new_fdt_addr, map);
219 }
220
221 #ifndef MAX_FDT_SIZE
222 # define MAX_FDT_SIZE SZ_2M
223 #endif
224
225 /*
226 * Allocate memory for a new FDT, then add EFI, commandline, and
227 * initrd related fields to the FDT. This routine increases the
228 * FDT allocation size until the allocated memory is large
229 * enough. EFI allocations are in EFI_PAGE_SIZE granules,
230 * which are fixed at 4K bytes, so in most cases the first
231 * allocation should succeed.
232 * EFI boot services are exited at the end of this function.
233 * There must be no allocations between the get_memory_map()
234 * call and the exit_boot_services() call, so the exiting of
235 * boot services is very tightly tied to the creation of the FDT
236 * with the final memory map in it.
237 */
238
allocate_new_fdt_and_exit_boot(void * handle,unsigned long * new_fdt_addr,u64 initrd_addr,u64 initrd_size,char * cmdline_ptr,unsigned long fdt_addr,unsigned long fdt_size)239 efi_status_t allocate_new_fdt_and_exit_boot(void *handle,
240 unsigned long *new_fdt_addr,
241 u64 initrd_addr, u64 initrd_size,
242 char *cmdline_ptr,
243 unsigned long fdt_addr,
244 unsigned long fdt_size)
245 {
246 unsigned long map_size, desc_size, buff_size;
247 u32 desc_ver;
248 unsigned long mmap_key;
249 efi_memory_desc_t *memory_map, *runtime_map;
250 efi_status_t status;
251 int runtime_entry_count;
252 struct efi_boot_memmap map;
253 struct exit_boot_struct priv;
254
255 map.map = &runtime_map;
256 map.map_size = &map_size;
257 map.desc_size = &desc_size;
258 map.desc_ver = &desc_ver;
259 map.key_ptr = &mmap_key;
260 map.buff_size = &buff_size;
261
262 /*
263 * Get a copy of the current memory map that we will use to prepare
264 * the input for SetVirtualAddressMap(). We don't have to worry about
265 * subsequent allocations adding entries, since they could not affect
266 * the number of EFI_MEMORY_RUNTIME regions.
267 */
268 status = efi_get_memory_map(&map);
269 if (status != EFI_SUCCESS) {
270 efi_err("Unable to retrieve UEFI memory map.\n");
271 return status;
272 }
273
274 efi_info("Exiting boot services and installing virtual address map...\n");
275
276 map.map = &memory_map;
277 status = efi_allocate_pages(MAX_FDT_SIZE, new_fdt_addr, ULONG_MAX);
278 if (status != EFI_SUCCESS) {
279 efi_err("Unable to allocate memory for new device tree.\n");
280 goto fail;
281 }
282
283 /*
284 * Now that we have done our final memory allocation (and free)
285 * we can get the memory map key needed for exit_boot_services().
286 */
287 status = efi_get_memory_map(&map);
288 if (status != EFI_SUCCESS)
289 goto fail_free_new_fdt;
290
291 status = update_fdt((void *)fdt_addr, fdt_size,
292 (void *)*new_fdt_addr, MAX_FDT_SIZE, cmdline_ptr,
293 initrd_addr, initrd_size);
294
295 if (status != EFI_SUCCESS) {
296 efi_err("Unable to construct new device tree.\n");
297 goto fail_free_new_fdt;
298 }
299
300 runtime_entry_count = 0;
301 priv.runtime_map = runtime_map;
302 priv.runtime_entry_count = &runtime_entry_count;
303 priv.new_fdt_addr = (void *)*new_fdt_addr;
304
305 status = efi_exit_boot_services(handle, &map, &priv, exit_boot_func);
306
307 if (status == EFI_SUCCESS) {
308 efi_set_virtual_address_map_t *svam;
309
310 if (efi_novamap)
311 return EFI_SUCCESS;
312
313 /* Install the new virtual address map */
314 svam = efi_system_table->runtime->set_virtual_address_map;
315 status = svam(runtime_entry_count * desc_size, desc_size,
316 desc_ver, runtime_map);
317
318 /*
319 * We are beyond the point of no return here, so if the call to
320 * SetVirtualAddressMap() failed, we need to signal that to the
321 * incoming kernel but proceed normally otherwise.
322 */
323 if (status != EFI_SUCCESS) {
324 int l;
325
326 /*
327 * Set the virtual address field of all
328 * EFI_MEMORY_RUNTIME entries to 0. This will signal
329 * the incoming kernel that no virtual translation has
330 * been installed.
331 */
332 for (l = 0; l < map_size; l += desc_size) {
333 efi_memory_desc_t *p = (void *)memory_map + l;
334
335 if (p->attribute & EFI_MEMORY_RUNTIME)
336 p->virt_addr = 0;
337 }
338 }
339 return EFI_SUCCESS;
340 }
341
342 efi_err("Exit boot services failed.\n");
343
344 fail_free_new_fdt:
345 efi_free(MAX_FDT_SIZE, *new_fdt_addr);
346
347 fail:
348 efi_system_table->boottime->free_pool(runtime_map);
349
350 return EFI_LOAD_ERROR;
351 }
352
get_fdt(unsigned long * fdt_size)353 void *get_fdt(unsigned long *fdt_size)
354 {
355 void *fdt;
356
357 fdt = get_efi_config_table(DEVICE_TREE_GUID);
358
359 if (!fdt)
360 return NULL;
361
362 if (fdt_check_header(fdt) != 0) {
363 efi_err("Invalid header detected on UEFI supplied FDT, ignoring ...\n");
364 return NULL;
365 }
366 *fdt_size = fdt_totalsize(fdt);
367 return fdt;
368 }
369