1 /*
2 * EFI stub implementation that is shared by arm and arm64 architectures.
3 * This should be #included by the EFI stub implementation files.
4 *
5 * Copyright (C) 2013,2014 Linaro Limited
6 * Roy Franz <roy.franz@linaro.org
7 * Copyright (C) 2013 Red Hat, Inc.
8 * Mark Salter <msalter@redhat.com>
9 *
10 * This file is part of the Linux kernel, and is made available under the
11 * terms of the GNU General Public License version 2.
12 *
13 */
14
15 #include <linux/efi.h>
16 #include <linux/sort.h>
17 #include <asm/efi.h>
18
19 #include "efistub.h"
20
efi_secureboot_enabled(efi_system_table_t * sys_table_arg)21 static int efi_secureboot_enabled(efi_system_table_t *sys_table_arg)
22 {
23 static efi_guid_t const var_guid = EFI_GLOBAL_VARIABLE_GUID;
24 static efi_char16_t const var_name[] = {
25 'S', 'e', 'c', 'u', 'r', 'e', 'B', 'o', 'o', 't', 0 };
26
27 efi_get_variable_t *f_getvar = sys_table_arg->runtime->get_variable;
28 unsigned long size = sizeof(u8);
29 efi_status_t status;
30 u8 val;
31
32 status = f_getvar((efi_char16_t *)var_name, (efi_guid_t *)&var_guid,
33 NULL, &size, &val);
34
35 switch (status) {
36 case EFI_SUCCESS:
37 return val;
38 case EFI_NOT_FOUND:
39 return 0;
40 default:
41 return 1;
42 }
43 }
44
efi_open_volume(efi_system_table_t * sys_table_arg,void * __image,void ** __fh)45 efi_status_t efi_open_volume(efi_system_table_t *sys_table_arg,
46 void *__image, void **__fh)
47 {
48 efi_file_io_interface_t *io;
49 efi_loaded_image_t *image = __image;
50 efi_file_handle_t *fh;
51 efi_guid_t fs_proto = EFI_FILE_SYSTEM_GUID;
52 efi_status_t status;
53 void *handle = (void *)(unsigned long)image->device_handle;
54
55 status = sys_table_arg->boottime->handle_protocol(handle,
56 &fs_proto, (void **)&io);
57 if (status != EFI_SUCCESS) {
58 efi_printk(sys_table_arg, "Failed to handle fs_proto\n");
59 return status;
60 }
61
62 status = io->open_volume(io, &fh);
63 if (status != EFI_SUCCESS)
64 efi_printk(sys_table_arg, "Failed to open volume\n");
65
66 *__fh = fh;
67 return status;
68 }
69
efi_file_close(void * handle)70 efi_status_t efi_file_close(void *handle)
71 {
72 efi_file_handle_t *fh = handle;
73
74 return fh->close(handle);
75 }
76
77 efi_status_t
efi_file_read(void * handle,unsigned long * size,void * addr)78 efi_file_read(void *handle, unsigned long *size, void *addr)
79 {
80 efi_file_handle_t *fh = handle;
81
82 return fh->read(handle, size, addr);
83 }
84
85
86 efi_status_t
efi_file_size(efi_system_table_t * sys_table_arg,void * __fh,efi_char16_t * filename_16,void ** handle,u64 * file_sz)87 efi_file_size(efi_system_table_t *sys_table_arg, void *__fh,
88 efi_char16_t *filename_16, void **handle, u64 *file_sz)
89 {
90 efi_file_handle_t *h, *fh = __fh;
91 efi_file_info_t *info;
92 efi_status_t status;
93 efi_guid_t info_guid = EFI_FILE_INFO_ID;
94 unsigned long info_sz;
95
96 status = fh->open(fh, &h, filename_16, EFI_FILE_MODE_READ, (u64)0);
97 if (status != EFI_SUCCESS) {
98 efi_printk(sys_table_arg, "Failed to open file: ");
99 efi_char16_printk(sys_table_arg, filename_16);
100 efi_printk(sys_table_arg, "\n");
101 return status;
102 }
103
104 *handle = h;
105
106 info_sz = 0;
107 status = h->get_info(h, &info_guid, &info_sz, NULL);
108 if (status != EFI_BUFFER_TOO_SMALL) {
109 efi_printk(sys_table_arg, "Failed to get file info size\n");
110 return status;
111 }
112
113 grow:
114 status = sys_table_arg->boottime->allocate_pool(EFI_LOADER_DATA,
115 info_sz, (void **)&info);
116 if (status != EFI_SUCCESS) {
117 efi_printk(sys_table_arg, "Failed to alloc mem for file info\n");
118 return status;
119 }
120
121 status = h->get_info(h, &info_guid, &info_sz,
122 info);
123 if (status == EFI_BUFFER_TOO_SMALL) {
124 sys_table_arg->boottime->free_pool(info);
125 goto grow;
126 }
127
128 *file_sz = info->file_size;
129 sys_table_arg->boottime->free_pool(info);
130
131 if (status != EFI_SUCCESS)
132 efi_printk(sys_table_arg, "Failed to get initrd info\n");
133
134 return status;
135 }
136
137
138
efi_char16_printk(efi_system_table_t * sys_table_arg,efi_char16_t * str)139 void efi_char16_printk(efi_system_table_t *sys_table_arg,
140 efi_char16_t *str)
141 {
142 struct efi_simple_text_output_protocol *out;
143
144 out = (struct efi_simple_text_output_protocol *)sys_table_arg->con_out;
145 out->output_string(out, str);
146 }
147
148
149 /*
150 * This function handles the architcture specific differences between arm and
151 * arm64 regarding where the kernel image must be loaded and any memory that
152 * must be reserved. On failure it is required to free all
153 * all allocations it has made.
154 */
155 efi_status_t handle_kernel_image(efi_system_table_t *sys_table,
156 unsigned long *image_addr,
157 unsigned long *image_size,
158 unsigned long *reserve_addr,
159 unsigned long *reserve_size,
160 unsigned long dram_base,
161 efi_loaded_image_t *image);
162 /*
163 * EFI entry point for the arm/arm64 EFI stubs. This is the entrypoint
164 * that is described in the PE/COFF header. Most of the code is the same
165 * for both archictectures, with the arch-specific code provided in the
166 * handle_kernel_image() function.
167 */
efi_entry(void * handle,efi_system_table_t * sys_table,unsigned long * image_addr)168 unsigned long efi_entry(void *handle, efi_system_table_t *sys_table,
169 unsigned long *image_addr)
170 {
171 efi_loaded_image_t *image;
172 efi_status_t status;
173 unsigned long image_size = 0;
174 unsigned long dram_base;
175 /* addr/point and size pairs for memory management*/
176 unsigned long initrd_addr;
177 u64 initrd_size = 0;
178 unsigned long fdt_addr = 0; /* Original DTB */
179 unsigned long fdt_size = 0;
180 char *cmdline_ptr = NULL;
181 int cmdline_size = 0;
182 unsigned long new_fdt_addr;
183 efi_guid_t loaded_image_proto = LOADED_IMAGE_PROTOCOL_GUID;
184 unsigned long reserve_addr = 0;
185 unsigned long reserve_size = 0;
186
187 /* Check if we were booted by the EFI firmware */
188 if (sys_table->hdr.signature != EFI_SYSTEM_TABLE_SIGNATURE)
189 goto fail;
190
191 pr_efi(sys_table, "Booting Linux Kernel...\n");
192
193 /*
194 * Get a handle to the loaded image protocol. This is used to get
195 * information about the running image, such as size and the command
196 * line.
197 */
198 status = sys_table->boottime->handle_protocol(handle,
199 &loaded_image_proto, (void *)&image);
200 if (status != EFI_SUCCESS) {
201 pr_efi_err(sys_table, "Failed to get loaded image protocol\n");
202 goto fail;
203 }
204
205 dram_base = get_dram_base(sys_table);
206 if (dram_base == EFI_ERROR) {
207 pr_efi_err(sys_table, "Failed to find DRAM base\n");
208 goto fail;
209 }
210
211 /*
212 * Get the command line from EFI, using the LOADED_IMAGE
213 * protocol. We are going to copy the command line into the
214 * device tree, so this can be allocated anywhere.
215 */
216 cmdline_ptr = efi_convert_cmdline(sys_table, image, &cmdline_size);
217 if (!cmdline_ptr) {
218 pr_efi_err(sys_table, "getting command line via LOADED_IMAGE_PROTOCOL\n");
219 goto fail;
220 }
221
222 status = handle_kernel_image(sys_table, image_addr, &image_size,
223 &reserve_addr,
224 &reserve_size,
225 dram_base, image);
226 if (status != EFI_SUCCESS) {
227 pr_efi_err(sys_table, "Failed to relocate kernel\n");
228 goto fail_free_cmdline;
229 }
230
231 if (IS_ENABLED(CONFIG_CMDLINE_EXTEND) ||
232 IS_ENABLED(CONFIG_CMDLINE_FORCE) ||
233 cmdline_size == 0)
234 efi_parse_options(CONFIG_CMDLINE);
235
236 if (!IS_ENABLED(CONFIG_CMDLINE_FORCE) && cmdline_size > 0)
237 efi_parse_options(cmdline_ptr);
238
239 /*
240 * Unauthenticated device tree data is a security hazard, so
241 * ignore 'dtb=' unless UEFI Secure Boot is disabled.
242 */
243 if (efi_secureboot_enabled(sys_table)) {
244 pr_efi(sys_table, "UEFI Secure Boot is enabled.\n");
245 } else {
246 status = handle_cmdline_files(sys_table, image, cmdline_ptr,
247 "dtb=",
248 ~0UL, &fdt_addr, &fdt_size);
249
250 if (status != EFI_SUCCESS) {
251 pr_efi_err(sys_table, "Failed to load device tree!\n");
252 goto fail_free_image;
253 }
254 }
255
256 if (fdt_addr) {
257 pr_efi(sys_table, "Using DTB from command line\n");
258 } else {
259 /* Look for a device tree configuration table entry. */
260 fdt_addr = (uintptr_t)get_fdt(sys_table, &fdt_size);
261 if (fdt_addr)
262 pr_efi(sys_table, "Using DTB from configuration table\n");
263 }
264
265 if (!fdt_addr)
266 pr_efi(sys_table, "Generating empty DTB\n");
267
268 status = handle_cmdline_files(sys_table, image, cmdline_ptr,
269 "initrd=", dram_base + SZ_512M,
270 (unsigned long *)&initrd_addr,
271 (unsigned long *)&initrd_size);
272 if (status != EFI_SUCCESS)
273 pr_efi_err(sys_table, "Failed initrd from command line!\n");
274
275 new_fdt_addr = fdt_addr;
276 status = allocate_new_fdt_and_exit_boot(sys_table, handle,
277 &new_fdt_addr, dram_base + MAX_FDT_OFFSET,
278 initrd_addr, initrd_size, cmdline_ptr,
279 fdt_addr, fdt_size);
280
281 /*
282 * If all went well, we need to return the FDT address to the
283 * calling function so it can be passed to kernel as part of
284 * the kernel boot protocol.
285 */
286 if (status == EFI_SUCCESS)
287 return new_fdt_addr;
288
289 pr_efi_err(sys_table, "Failed to update FDT and exit boot services\n");
290
291 efi_free(sys_table, initrd_size, initrd_addr);
292 efi_free(sys_table, fdt_size, fdt_addr);
293
294 fail_free_image:
295 efi_free(sys_table, image_size, *image_addr);
296 efi_free(sys_table, reserve_size, reserve_addr);
297 fail_free_cmdline:
298 efi_free(sys_table, cmdline_size, (unsigned long)cmdline_ptr);
299 fail:
300 return EFI_ERROR;
301 }
302
303 /*
304 * This is the base address at which to start allocating virtual memory ranges
305 * for UEFI Runtime Services. This is in the low TTBR0 range so that we can use
306 * any allocation we choose, and eliminate the risk of a conflict after kexec.
307 * The value chosen is the largest non-zero power of 2 suitable for this purpose
308 * both on 32-bit and 64-bit ARM CPUs, to maximize the likelihood that it can
309 * be mapped efficiently.
310 */
311 #define EFI_RT_VIRTUAL_BASE 0x40000000
312
cmp_mem_desc(const void * l,const void * r)313 static int cmp_mem_desc(const void *l, const void *r)
314 {
315 const efi_memory_desc_t *left = l, *right = r;
316
317 return (left->phys_addr > right->phys_addr) ? 1 : -1;
318 }
319
320 /*
321 * Returns whether region @left ends exactly where region @right starts,
322 * or false if either argument is NULL.
323 */
regions_are_adjacent(efi_memory_desc_t * left,efi_memory_desc_t * right)324 static bool regions_are_adjacent(efi_memory_desc_t *left,
325 efi_memory_desc_t *right)
326 {
327 u64 left_end;
328
329 if (left == NULL || right == NULL)
330 return false;
331
332 left_end = left->phys_addr + left->num_pages * EFI_PAGE_SIZE;
333
334 return left_end == right->phys_addr;
335 }
336
337 /*
338 * Returns whether region @left and region @right have compatible memory type
339 * mapping attributes, and are both EFI_MEMORY_RUNTIME regions.
340 */
regions_have_compatible_memory_type_attrs(efi_memory_desc_t * left,efi_memory_desc_t * right)341 static bool regions_have_compatible_memory_type_attrs(efi_memory_desc_t *left,
342 efi_memory_desc_t *right)
343 {
344 static const u64 mem_type_mask = EFI_MEMORY_WB | EFI_MEMORY_WT |
345 EFI_MEMORY_WC | EFI_MEMORY_UC |
346 EFI_MEMORY_RUNTIME;
347
348 return ((left->attribute ^ right->attribute) & mem_type_mask) == 0;
349 }
350
351 /*
352 * efi_get_virtmap() - create a virtual mapping for the EFI memory map
353 *
354 * This function populates the virt_addr fields of all memory region descriptors
355 * in @memory_map whose EFI_MEMORY_RUNTIME attribute is set. Those descriptors
356 * are also copied to @runtime_map, and their total count is returned in @count.
357 */
efi_get_virtmap(efi_memory_desc_t * memory_map,unsigned long map_size,unsigned long desc_size,efi_memory_desc_t * runtime_map,int * count)358 void efi_get_virtmap(efi_memory_desc_t *memory_map, unsigned long map_size,
359 unsigned long desc_size, efi_memory_desc_t *runtime_map,
360 int *count)
361 {
362 u64 efi_virt_base = EFI_RT_VIRTUAL_BASE;
363 efi_memory_desc_t *in, *prev = NULL, *out = runtime_map;
364 int l;
365
366 /*
367 * To work around potential issues with the Properties Table feature
368 * introduced in UEFI 2.5, which may split PE/COFF executable images
369 * in memory into several RuntimeServicesCode and RuntimeServicesData
370 * regions, we need to preserve the relative offsets between adjacent
371 * EFI_MEMORY_RUNTIME regions with the same memory type attributes.
372 * The easiest way to find adjacent regions is to sort the memory map
373 * before traversing it.
374 */
375 sort(memory_map, map_size / desc_size, desc_size, cmp_mem_desc, NULL);
376
377 for (l = 0; l < map_size; l += desc_size, prev = in) {
378 u64 paddr, size;
379
380 in = (void *)memory_map + l;
381 if (!(in->attribute & EFI_MEMORY_RUNTIME))
382 continue;
383
384 paddr = in->phys_addr;
385 size = in->num_pages * EFI_PAGE_SIZE;
386
387 /*
388 * Make the mapping compatible with 64k pages: this allows
389 * a 4k page size kernel to kexec a 64k page size kernel and
390 * vice versa.
391 */
392 if (!regions_are_adjacent(prev, in) ||
393 !regions_have_compatible_memory_type_attrs(prev, in)) {
394
395 paddr = round_down(in->phys_addr, SZ_64K);
396 size += in->phys_addr - paddr;
397
398 /*
399 * Avoid wasting memory on PTEs by choosing a virtual
400 * base that is compatible with section mappings if this
401 * region has the appropriate size and physical
402 * alignment. (Sections are 2 MB on 4k granule kernels)
403 */
404 if (IS_ALIGNED(in->phys_addr, SZ_2M) && size >= SZ_2M)
405 efi_virt_base = round_up(efi_virt_base, SZ_2M);
406 else
407 efi_virt_base = round_up(efi_virt_base, SZ_64K);
408 }
409
410 in->virt_addr = efi_virt_base + in->phys_addr - paddr;
411 efi_virt_base += size;
412
413 memcpy(out, in, desc_size);
414 out = (void *)out + desc_size;
415 ++*count;
416 }
417 }
418