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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
21bool __nokaslr;
22
23static int efi_secureboot_enabled(efi_system_table_t *sys_table_arg)
24{
25 static efi_guid_t const var_guid = EFI_GLOBAL_VARIABLE_GUID;
26 static efi_char16_t const var_name[] = {
27 'S', 'e', 'c', 'u', 'r', 'e', 'B', 'o', 'o', 't', 0 };
28
29 efi_get_variable_t *f_getvar = sys_table_arg->runtime->get_variable;
30 unsigned long size = sizeof(u8);
31 efi_status_t status;
32 u8 val;
33
34 status = f_getvar((efi_char16_t *)var_name, (efi_guid_t *)&var_guid,
35 NULL, &size, &val);
36
37 switch (status) {
38 case EFI_SUCCESS:
39 return val;
40 case EFI_NOT_FOUND:
41 return 0;
42 default:
43 return 1;
44 }
45}
46
47efi_status_t efi_open_volume(efi_system_table_t *sys_table_arg,
48 void *__image, void **__fh)
49{
50 efi_file_io_interface_t *io;
51 efi_loaded_image_t *image = __image;
52 efi_file_handle_t *fh;
53 efi_guid_t fs_proto = EFI_FILE_SYSTEM_GUID;
54 efi_status_t status;
55 void *handle = (void *)(unsigned long)image->device_handle;
56
57 status = sys_table_arg->boottime->handle_protocol(handle,
58 &fs_proto, (void **)&io);
59 if (status != EFI_SUCCESS) {
60 efi_printk(sys_table_arg, "Failed to handle fs_proto\n");
61 return status;
62 }
63
64 status = io->open_volume(io, &fh);
65 if (status != EFI_SUCCESS)
66 efi_printk(sys_table_arg, "Failed to open volume\n");
67
68 *__fh = fh;
69 return status;
70}
71
72efi_status_t efi_file_close(void *handle)
73{
74 efi_file_handle_t *fh = handle;
75
76 return fh->close(handle);
77}
78
79efi_status_t
80efi_file_read(void *handle, unsigned long *size, void *addr)
81{
82 efi_file_handle_t *fh = handle;
83
84 return fh->read(handle, size, addr);
85}
86
87
88efi_status_t
89efi_file_size(efi_system_table_t *sys_table_arg, void *__fh,
90 efi_char16_t *filename_16, void **handle, u64 *file_sz)
91{
92 efi_file_handle_t *h, *fh = __fh;
93 efi_file_info_t *info;
94 efi_status_t status;
95 efi_guid_t info_guid = EFI_FILE_INFO_ID;
96 unsigned long info_sz;
97
98 status = fh->open(fh, &h, filename_16, EFI_FILE_MODE_READ, (u64)0);
99 if (status != EFI_SUCCESS) {
100 efi_printk(sys_table_arg, "Failed to open file: ");
101 efi_char16_printk(sys_table_arg, filename_16);
102 efi_printk(sys_table_arg, "\n");
103 return status;
104 }
105
106 *handle = h;
107
108 info_sz = 0;
109 status = h->get_info(h, &info_guid, &info_sz, NULL);
110 if (status != EFI_BUFFER_TOO_SMALL) {
111 efi_printk(sys_table_arg, "Failed to get file info size\n");
112 return status;
113 }
114
115grow:
116 status = sys_table_arg->boottime->allocate_pool(EFI_LOADER_DATA,
117 info_sz, (void **)&info);
118 if (status != EFI_SUCCESS) {
119 efi_printk(sys_table_arg, "Failed to alloc mem for file info\n");
120 return status;
121 }
122
123 status = h->get_info(h, &info_guid, &info_sz,
124 info);
125 if (status == EFI_BUFFER_TOO_SMALL) {
126 sys_table_arg->boottime->free_pool(info);
127 goto grow;
128 }
129
130 *file_sz = info->file_size;
131 sys_table_arg->boottime->free_pool(info);
132
133 if (status != EFI_SUCCESS)
134 efi_printk(sys_table_arg, "Failed to get initrd info\n");
135
136 return status;
137}
138
139
140
141void efi_char16_printk(efi_system_table_t *sys_table_arg,
142 efi_char16_t *str)
143{
144 struct efi_simple_text_output_protocol *out;
145
146 out = (struct efi_simple_text_output_protocol *)sys_table_arg->con_out;
147 out->output_string(out, str);
148}
149
150
151/*
152 * This function handles the architcture specific differences between arm and
153 * arm64 regarding where the kernel image must be loaded and any memory that
154 * must be reserved. On failure it is required to free all
155 * all allocations it has made.
156 */
157efi_status_t handle_kernel_image(efi_system_table_t *sys_table,
158 unsigned long *image_addr,
159 unsigned long *image_size,
160 unsigned long *reserve_addr,
161 unsigned long *reserve_size,
162 unsigned long dram_base,
163 efi_loaded_image_t *image);
164/*
165 * EFI entry point for the arm/arm64 EFI stubs. This is the entrypoint
166 * that is described in the PE/COFF header. Most of the code is the same
167 * for both archictectures, with the arch-specific code provided in the
168 * handle_kernel_image() function.
169 */
170unsigned long efi_entry(void *handle, efi_system_table_t *sys_table,
171 unsigned long *image_addr)
172{
173 efi_loaded_image_t *image;
174 efi_status_t status;
175 unsigned long image_size = 0;
176 unsigned long dram_base;
177 /* addr/point and size pairs for memory management*/
178 unsigned long initrd_addr;
179 u64 initrd_size = 0;
180 unsigned long fdt_addr = 0; /* Original DTB */
181 unsigned long fdt_size = 0;
182 char *cmdline_ptr = NULL;
183 int cmdline_size = 0;
184 unsigned long new_fdt_addr;
185 efi_guid_t loaded_image_proto = LOADED_IMAGE_PROTOCOL_GUID;
186 unsigned long reserve_addr = 0;
187 unsigned long reserve_size = 0;
188
189 /* Check if we were booted by the EFI firmware */
190 if (sys_table->hdr.signature != EFI_SYSTEM_TABLE_SIGNATURE)
191 goto fail;
192
193 pr_efi(sys_table, "Booting Linux Kernel...\n");
194
195 status = check_platform_features(sys_table);
196 if (status != EFI_SUCCESS)
197 goto fail;
198
199 /*
200 * Get a handle to the loaded image protocol. This is used to get
201 * information about the running image, such as size and the command
202 * line.
203 */
204 status = sys_table->boottime->handle_protocol(handle,
205 &loaded_image_proto, (void *)&image);
206 if (status != EFI_SUCCESS) {
207 pr_efi_err(sys_table, "Failed to get loaded image protocol\n");
208 goto fail;
209 }
210
211 dram_base = get_dram_base(sys_table);
212 if (dram_base == EFI_ERROR) {
213 pr_efi_err(sys_table, "Failed to find DRAM base\n");
214 goto fail;
215 }
216
217 /*
218 * Get the command line from EFI, using the LOADED_IMAGE
219 * protocol. We are going to copy the command line into the
220 * device tree, so this can be allocated anywhere.
221 */
222 cmdline_ptr = efi_convert_cmdline(sys_table, image, &cmdline_size);
223 if (!cmdline_ptr) {
224 pr_efi_err(sys_table, "getting command line via LOADED_IMAGE_PROTOCOL\n");
225 goto fail;
226 }
227
228 /* check whether 'nokaslr' was passed on the command line */
229 if (IS_ENABLED(CONFIG_RANDOMIZE_BASE)) {
230 static const u8 default_cmdline[] = CONFIG_CMDLINE;
231 const u8 *str, *cmdline = cmdline_ptr;
232
233 if (IS_ENABLED(CONFIG_CMDLINE_FORCE))
234 cmdline = default_cmdline;
235 str = strstr(cmdline, "nokaslr");
236 if (str == cmdline || (str > cmdline && *(str - 1) == ' '))
237 __nokaslr = true;
238 }
239
240 status = handle_kernel_image(sys_table, image_addr, &image_size,
241 &reserve_addr,
242 &reserve_size,
243 dram_base, image);
244 if (status != EFI_SUCCESS) {
245 pr_efi_err(sys_table, "Failed to relocate kernel\n");
246 goto fail_free_cmdline;
247 }
248
249 status = efi_parse_options(cmdline_ptr);
250 if (status != EFI_SUCCESS)
251 pr_efi_err(sys_table, "Failed to parse EFI cmdline options\n");
252
253 /*
254 * Unauthenticated device tree data is a security hazard, so
255 * ignore 'dtb=' unless UEFI Secure Boot is disabled.
256 */
257 if (efi_secureboot_enabled(sys_table)) {
258 pr_efi(sys_table, "UEFI Secure Boot is enabled.\n");
259 } else {
260 status = handle_cmdline_files(sys_table, image, cmdline_ptr,
261 "dtb=",
262 ~0UL, &fdt_addr, &fdt_size);
263
264 if (status != EFI_SUCCESS) {
265 pr_efi_err(sys_table, "Failed to load device tree!\n");
266 goto fail_free_image;
267 }
268 }
269
270 if (fdt_addr) {
271 pr_efi(sys_table, "Using DTB from command line\n");
272 } else {
273 /* Look for a device tree configuration table entry. */
274 fdt_addr = (uintptr_t)get_fdt(sys_table, &fdt_size);
275 if (fdt_addr)
276 pr_efi(sys_table, "Using DTB from configuration table\n");
277 }
278
279 if (!fdt_addr)
280 pr_efi(sys_table, "Generating empty DTB\n");
281
282 status = handle_cmdline_files(sys_table, image, cmdline_ptr,
283 "initrd=", dram_base + SZ_512M,
284 (unsigned long *)&initrd_addr,
285 (unsigned long *)&initrd_size);
286 if (status != EFI_SUCCESS)
287 pr_efi_err(sys_table, "Failed initrd from command line!\n");
288
289 new_fdt_addr = fdt_addr;
290 status = allocate_new_fdt_and_exit_boot(sys_table, handle,
291 &new_fdt_addr, dram_base + MAX_FDT_OFFSET,
292 initrd_addr, initrd_size, cmdline_ptr,
293 fdt_addr, fdt_size);
294
295 /*
296 * If all went well, we need to return the FDT address to the
297 * calling function so it can be passed to kernel as part of
298 * the kernel boot protocol.
299 */
300 if (status == EFI_SUCCESS)
301 return new_fdt_addr;
302
303 pr_efi_err(sys_table, "Failed to update FDT and exit boot services\n");
304
305 efi_free(sys_table, initrd_size, initrd_addr);
306 efi_free(sys_table, fdt_size, fdt_addr);
307
308fail_free_image:
309 efi_free(sys_table, image_size, *image_addr);
310 efi_free(sys_table, reserve_size, reserve_addr);
311fail_free_cmdline:
312 efi_free(sys_table, cmdline_size, (unsigned long)cmdline_ptr);
313fail:
314 return EFI_ERROR;
315}
316
317/*
318 * This is the base address at which to start allocating virtual memory ranges
319 * for UEFI Runtime Services. This is in the low TTBR0 range so that we can use
320 * any allocation we choose, and eliminate the risk of a conflict after kexec.
321 * The value chosen is the largest non-zero power of 2 suitable for this purpose
322 * both on 32-bit and 64-bit ARM CPUs, to maximize the likelihood that it can
323 * be mapped efficiently.
324 * Since 32-bit ARM could potentially execute with a 1G/3G user/kernel split,
325 * map everything below 1 GB.
326 */
327#define EFI_RT_VIRTUAL_BASE SZ_512M
328
329static int cmp_mem_desc(const void *l, const void *r)
330{
331 const efi_memory_desc_t *left = l, *right = r;
332
333 return (left->phys_addr > right->phys_addr) ? 1 : -1;
334}
335
336/*
337 * Returns whether region @left ends exactly where region @right starts,
338 * or false if either argument is NULL.
339 */
340static bool regions_are_adjacent(efi_memory_desc_t *left,
341 efi_memory_desc_t *right)
342{
343 u64 left_end;
344
345 if (left == NULL || right == NULL)
346 return false;
347
348 left_end = left->phys_addr + left->num_pages * EFI_PAGE_SIZE;
349
350 return left_end == right->phys_addr;
351}
352
353/*
354 * Returns whether region @left and region @right have compatible memory type
355 * mapping attributes, and are both EFI_MEMORY_RUNTIME regions.
356 */
357static bool regions_have_compatible_memory_type_attrs(efi_memory_desc_t *left,
358 efi_memory_desc_t *right)
359{
360 static const u64 mem_type_mask = EFI_MEMORY_WB | EFI_MEMORY_WT |
361 EFI_MEMORY_WC | EFI_MEMORY_UC |
362 EFI_MEMORY_RUNTIME;
363
364 return ((left->attribute ^ right->attribute) & mem_type_mask) == 0;
365}
366
367/*
368 * efi_get_virtmap() - create a virtual mapping for the EFI memory map
369 *
370 * This function populates the virt_addr fields of all memory region descriptors
371 * in @memory_map whose EFI_MEMORY_RUNTIME attribute is set. Those descriptors
372 * are also copied to @runtime_map, and their total count is returned in @count.
373 */
374void efi_get_virtmap(efi_memory_desc_t *memory_map, unsigned long map_size,
375 unsigned long desc_size, efi_memory_desc_t *runtime_map,
376 int *count)
377{
378 u64 efi_virt_base = EFI_RT_VIRTUAL_BASE;
379 efi_memory_desc_t *in, *prev = NULL, *out = runtime_map;
380 int l;
381
382 /*
383 * To work around potential issues with the Properties Table feature
384 * introduced in UEFI 2.5, which may split PE/COFF executable images
385 * in memory into several RuntimeServicesCode and RuntimeServicesData
386 * regions, we need to preserve the relative offsets between adjacent
387 * EFI_MEMORY_RUNTIME regions with the same memory type attributes.
388 * The easiest way to find adjacent regions is to sort the memory map
389 * before traversing it.
390 */
391 sort(memory_map, map_size / desc_size, desc_size, cmp_mem_desc, NULL);
392
393 for (l = 0; l < map_size; l += desc_size, prev = in) {
394 u64 paddr, size;
395
396 in = (void *)memory_map + l;
397 if (!(in->attribute & EFI_MEMORY_RUNTIME))
398 continue;
399
400 paddr = in->phys_addr;
401 size = in->num_pages * EFI_PAGE_SIZE;
402
403 /*
404 * Make the mapping compatible with 64k pages: this allows
405 * a 4k page size kernel to kexec a 64k page size kernel and
406 * vice versa.
407 */
408 if (!regions_are_adjacent(prev, in) ||
409 !regions_have_compatible_memory_type_attrs(prev, in)) {
410
411 paddr = round_down(in->phys_addr, SZ_64K);
412 size += in->phys_addr - paddr;
413
414 /*
415 * Avoid wasting memory on PTEs by choosing a virtual
416 * base that is compatible with section mappings if this
417 * region has the appropriate size and physical
418 * alignment. (Sections are 2 MB on 4k granule kernels)
419 */
420 if (IS_ALIGNED(in->phys_addr, SZ_2M) && size >= SZ_2M)
421 efi_virt_base = round_up(efi_virt_base, SZ_2M);
422 else
423 efi_virt_base = round_up(efi_virt_base, SZ_64K);
424 }
425
426 in->virt_addr = efi_virt_base + in->phys_addr - paddr;
427 efi_virt_base += size;
428
429 memcpy(out, in, desc_size);
430 out = (void *)out + desc_size;
431 ++*count;
432 }
433}