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