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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
19static 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
30static efi_status_t update_fdt(void *orig_fdt, unsigned long orig_fdt_size,
31 void *fdt, int new_fdt_size, char *cmdline_ptr)
32{
33 int node, num_rsv;
34 int status;
35 u32 fdt_val32;
36 u64 fdt_val64;
37
38 /* Do some checks on provided FDT, if it exists: */
39 if (orig_fdt) {
40 if (fdt_check_header(orig_fdt)) {
41 efi_err("Device Tree header not valid!\n");
42 return EFI_LOAD_ERROR;
43 }
44 /*
45 * We don't get the size of the FDT if we get if from a
46 * configuration table:
47 */
48 if (orig_fdt_size && fdt_totalsize(orig_fdt) > orig_fdt_size) {
49 efi_err("Truncated device tree! foo!\n");
50 return EFI_LOAD_ERROR;
51 }
52 }
53
54 if (orig_fdt) {
55 status = fdt_open_into(orig_fdt, fdt, new_fdt_size);
56 } else {
57 status = fdt_create_empty_tree(fdt, new_fdt_size);
58 if (status == 0) {
59 /*
60 * Any failure from the following function is
61 * non-critical:
62 */
63 fdt_update_cell_size(fdt);
64 }
65 }
66
67 if (status != 0)
68 goto fdt_set_fail;
69
70 /*
71 * Delete all memory reserve map entries. When booting via UEFI,
72 * kernel will use the UEFI memory map to find reserved regions.
73 */
74 num_rsv = fdt_num_mem_rsv(fdt);
75 while (num_rsv-- > 0)
76 fdt_del_mem_rsv(fdt, num_rsv);
77
78 node = fdt_subnode_offset(fdt, 0, "chosen");
79 if (node < 0) {
80 node = fdt_add_subnode(fdt, 0, "chosen");
81 if (node < 0) {
82 /* 'node' is an error code when negative: */
83 status = node;
84 goto fdt_set_fail;
85 }
86 }
87
88 if (cmdline_ptr != NULL && strlen(cmdline_ptr) > 0) {
89 status = fdt_setprop(fdt, node, "bootargs", cmdline_ptr,
90 strlen(cmdline_ptr) + 1);
91 if (status)
92 goto fdt_set_fail;
93 }
94
95 /* Add FDT entries for EFI runtime services in chosen node. */
96 node = fdt_subnode_offset(fdt, 0, "chosen");
97 fdt_val64 = cpu_to_fdt64((u64)(unsigned long)efi_system_table);
98
99 status = fdt_setprop_var(fdt, node, "linux,uefi-system-table", fdt_val64);
100 if (status)
101 goto fdt_set_fail;
102
103 fdt_val64 = U64_MAX; /* placeholder */
104
105 status = fdt_setprop_var(fdt, node, "linux,uefi-mmap-start", fdt_val64);
106 if (status)
107 goto fdt_set_fail;
108
109 fdt_val32 = U32_MAX; /* placeholder */
110
111 status = fdt_setprop_var(fdt, node, "linux,uefi-mmap-size", fdt_val32);
112 if (status)
113 goto fdt_set_fail;
114
115 status = fdt_setprop_var(fdt, node, "linux,uefi-mmap-desc-size", fdt_val32);
116 if (status)
117 goto fdt_set_fail;
118
119 status = fdt_setprop_var(fdt, node, "linux,uefi-mmap-desc-ver", fdt_val32);
120 if (status)
121 goto fdt_set_fail;
122
123 if (IS_ENABLED(CONFIG_RANDOMIZE_BASE) && !efi_nokaslr) {
124 efi_status_t efi_status;
125
126 efi_status = efi_get_random_bytes(sizeof(fdt_val64),
127 (u8 *)&fdt_val64);
128 if (efi_status == EFI_SUCCESS) {
129 status = fdt_setprop_var(fdt, node, "kaslr-seed", fdt_val64);
130 if (status)
131 goto fdt_set_fail;
132 }
133 }
134
135 /* Shrink the FDT back to its minimum size: */
136 fdt_pack(fdt);
137
138 return EFI_SUCCESS;
139
140fdt_set_fail:
141 if (status == -FDT_ERR_NOSPACE)
142 return EFI_BUFFER_TOO_SMALL;
143
144 return EFI_LOAD_ERROR;
145}
146
147static efi_status_t update_fdt_memmap(void *fdt, struct efi_boot_memmap *map)
148{
149 int node = fdt_path_offset(fdt, "/chosen");
150 u64 fdt_val64;
151 u32 fdt_val32;
152 int err;
153
154 if (node < 0)
155 return EFI_LOAD_ERROR;
156
157 fdt_val64 = cpu_to_fdt64((unsigned long)map->map);
158
159 err = fdt_setprop_inplace_var(fdt, node, "linux,uefi-mmap-start", fdt_val64);
160 if (err)
161 return EFI_LOAD_ERROR;
162
163 fdt_val32 = cpu_to_fdt32(map->map_size);
164
165 err = fdt_setprop_inplace_var(fdt, node, "linux,uefi-mmap-size", fdt_val32);
166 if (err)
167 return EFI_LOAD_ERROR;
168
169 fdt_val32 = cpu_to_fdt32(map->desc_size);
170
171 err = fdt_setprop_inplace_var(fdt, node, "linux,uefi-mmap-desc-size", fdt_val32);
172 if (err)
173 return EFI_LOAD_ERROR;
174
175 fdt_val32 = cpu_to_fdt32(map->desc_ver);
176
177 err = fdt_setprop_inplace_var(fdt, node, "linux,uefi-mmap-desc-ver", fdt_val32);
178 if (err)
179 return EFI_LOAD_ERROR;
180
181 return EFI_SUCCESS;
182}
183
184struct exit_boot_struct {
185 struct efi_boot_memmap *boot_memmap;
186 efi_memory_desc_t *runtime_map;
187 int runtime_entry_count;
188 void *new_fdt_addr;
189};
190
191static efi_status_t exit_boot_func(struct efi_boot_memmap *map, void *priv)
192{
193 struct exit_boot_struct *p = priv;
194
195 p->boot_memmap = map;
196
197 /*
198 * Update the memory map with virtual addresses. The function will also
199 * populate @runtime_map with copies of just the EFI_MEMORY_RUNTIME
200 * entries so that we can pass it straight to SetVirtualAddressMap()
201 */
202 efi_get_virtmap(map->map, map->map_size, map->desc_size,
203 p->runtime_map, &p->runtime_entry_count);
204
205 return update_fdt_memmap(p->new_fdt_addr, map);
206}
207
208#ifndef MAX_FDT_SIZE
209# define MAX_FDT_SIZE SZ_2M
210#endif
211
212/*
213 * Allocate memory for a new FDT, then add EFI and commandline related fields
214 * to the FDT. This routine increases the FDT allocation size until the
215 * allocated memory is large enough. EFI allocations are in EFI_PAGE_SIZE
216 * granules, which are fixed at 4K bytes, so in most cases the first allocation
217 * should succeed. EFI boot services are exited at the end of this function.
218 * There must be no allocations between the get_memory_map() call and the
219 * exit_boot_services() call, so the exiting of boot services is very tightly
220 * tied to the creation of the FDT with the final memory map in it.
221 */
222static
223efi_status_t allocate_new_fdt_and_exit_boot(void *handle,
224 efi_loaded_image_t *image,
225 unsigned long *new_fdt_addr,
226 char *cmdline_ptr)
227{
228 unsigned long desc_size;
229 u32 desc_ver;
230 efi_status_t status;
231 struct exit_boot_struct priv;
232 unsigned long fdt_addr = 0;
233 unsigned long fdt_size = 0;
234
235 if (!efi_novamap) {
236 status = efi_alloc_virtmap(&priv.runtime_map, &desc_size,
237 &desc_ver);
238 if (status != EFI_SUCCESS) {
239 efi_err("Unable to retrieve UEFI memory map.\n");
240 return status;
241 }
242 }
243
244 /*
245 * Unauthenticated device tree data is a security hazard, so ignore
246 * 'dtb=' unless UEFI Secure Boot is disabled. We assume that secure
247 * boot is enabled if we can't determine its state.
248 */
249 if (!IS_ENABLED(CONFIG_EFI_ARMSTUB_DTB_LOADER) ||
250 efi_get_secureboot() != efi_secureboot_mode_disabled) {
251 if (strstr(cmdline_ptr, "dtb="))
252 efi_err("Ignoring DTB from command line.\n");
253 } else {
254 status = efi_load_dtb(image, &fdt_addr, &fdt_size);
255
256 if (status != EFI_SUCCESS && status != EFI_NOT_READY) {
257 efi_err("Failed to load device tree!\n");
258 goto fail;
259 }
260 }
261
262 if (fdt_addr) {
263 efi_info("Using DTB from command line\n");
264 } else {
265 /* Look for a device tree configuration table entry. */
266 fdt_addr = (uintptr_t)get_fdt(&fdt_size);
267 if (fdt_addr)
268 efi_info("Using DTB from configuration table\n");
269 }
270
271 if (!fdt_addr)
272 efi_info("Generating empty DTB\n");
273
274 efi_info("Exiting boot services...\n");
275
276 status = efi_allocate_pages(MAX_FDT_SIZE, new_fdt_addr, ULONG_MAX);
277 if (status != EFI_SUCCESS) {
278 efi_err("Unable to allocate memory for new device tree.\n");
279 goto fail;
280 }
281
282 status = update_fdt((void *)fdt_addr, fdt_size,
283 (void *)*new_fdt_addr, MAX_FDT_SIZE, cmdline_ptr);
284
285 if (status != EFI_SUCCESS) {
286 efi_err("Unable to construct new device tree.\n");
287 goto fail_free_new_fdt;
288 }
289
290 priv.new_fdt_addr = (void *)*new_fdt_addr;
291
292 status = efi_exit_boot_services(handle, &priv, exit_boot_func);
293
294 if (status == EFI_SUCCESS) {
295 efi_set_virtual_address_map_t *svam;
296
297 if (efi_novamap)
298 return EFI_SUCCESS;
299
300 /* Install the new virtual address map */
301 svam = efi_system_table->runtime->set_virtual_address_map;
302 status = svam(priv.runtime_entry_count * desc_size, desc_size,
303 desc_ver, priv.runtime_map);
304
305 /*
306 * We are beyond the point of no return here, so if the call to
307 * SetVirtualAddressMap() failed, we need to signal that to the
308 * incoming kernel but proceed normally otherwise.
309 */
310 if (status != EFI_SUCCESS) {
311 efi_memory_desc_t *p;
312 int l;
313
314 /*
315 * Set the virtual address field of all
316 * EFI_MEMORY_RUNTIME entries to U64_MAX. This will
317 * signal the incoming kernel that no virtual
318 * translation has been installed.
319 */
320 for (l = 0; l < priv.boot_memmap->map_size;
321 l += priv.boot_memmap->desc_size) {
322 p = (void *)priv.boot_memmap->map + l;
323
324 if (p->attribute & EFI_MEMORY_RUNTIME)
325 p->virt_addr = U64_MAX;
326 }
327 }
328 return EFI_SUCCESS;
329 }
330
331 efi_err("Exit boot services failed.\n");
332
333fail_free_new_fdt:
334 efi_free(MAX_FDT_SIZE, *new_fdt_addr);
335
336fail:
337 efi_free(fdt_size, fdt_addr);
338 if (!efi_novamap)
339 efi_bs_call(free_pool, priv.runtime_map);
340
341 return EFI_LOAD_ERROR;
342}
343
344efi_status_t efi_boot_kernel(void *handle, efi_loaded_image_t *image,
345 unsigned long kernel_addr, char *cmdline_ptr)
346{
347 unsigned long fdt_addr;
348 efi_status_t status;
349
350 status = allocate_new_fdt_and_exit_boot(handle, image, &fdt_addr,
351 cmdline_ptr);
352 if (status != EFI_SUCCESS) {
353 efi_err("Failed to update FDT and exit boot services\n");
354 return status;
355 }
356
357 if (IS_ENABLED(CONFIG_ARM))
358 efi_handle_post_ebs_state();
359
360 efi_enter_kernel(kernel_addr, fdt_addr, fdt_totalsize((void *)fdt_addr));
361 /* not reached */
362}
363
364void *get_fdt(unsigned long *fdt_size)
365{
366 void *fdt;
367
368 fdt = get_efi_config_table(DEVICE_TREE_GUID);
369
370 if (!fdt)
371 return NULL;
372
373 if (fdt_check_header(fdt) != 0) {
374 efi_err("Invalid header detected on UEFI supplied FDT, ignoring ...\n");
375 return NULL;
376 }
377 *fdt_size = fdt_totalsize(fdt);
378 return fdt;
379}