1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3 * Copyright (c) 2015 Google, Inc
4 *
5 * EFI information obtained here:
6 * http://wiki.phoenix.com/wiki/index.php/EFI_BOOT_SERVICES
7 *
8 * Loads a payload (U-Boot) within the EFI environment. This is built as an
9 * EFI application. It can be built either in 32-bit or 64-bit mode.
10 */
11
12 #include <common.h>
13 #include <debug_uart.h>
14 #include <efi.h>
15 #include <efi_api.h>
16 #include <errno.h>
17 #include <ns16550.h>
18 #include <asm/cpu.h>
19 #include <asm/io.h>
20 #include <linux/err.h>
21 #include <linux/types.h>
22
23 #ifndef CONFIG_X86
24 /*
25 * Problem areas:
26 * - putc() uses the ns16550 address directly and assumed I/O access. Many
27 * platforms will use memory access
28 * get_codeseg32() is only meaningful on x86
29 */
30 #error "This file needs to be ported for use on architectures"
31 #endif
32
33 static struct efi_priv *global_priv;
34 static bool use_uart;
35
36 struct __packed desctab_info {
37 uint16_t limit;
38 uint64_t addr;
39 uint16_t pad;
40 };
41
42 /*
43 * EFI uses Unicode and we don't. The easiest way to get a sensible output
44 * function is to use the U-Boot debug UART. We use EFI's console output
45 * function where available, and assume the built-in UART after that. We rely
46 * on EFI to set up the UART for us and just bring in the functions here.
47 * This last bit is a bit icky, but it's only for debugging anyway. We could
48 * build in ns16550.c with some effort, but this is a payload loader after
49 * all.
50 *
51 * Note: We avoid using printf() so we don't need to bring in lib/vsprintf.c.
52 * That would require some refactoring since we already build this for U-Boot.
53 * Building an EFI shared library version would have to be a separate stem.
54 * That might push us to using the SPL framework to build this stub. However
55 * that would involve a round of EFI-specific changes in SPL. Worth
56 * considering if we start needing more U-Boot functionality. Note that we
57 * could then move get_codeseg32() to arch/x86/cpu/cpu.c.
58 */
_debug_uart_init(void)59 void _debug_uart_init(void)
60 {
61 }
62
putc(const char ch)63 void putc(const char ch)
64 {
65 if (ch == '\n')
66 putc('\r');
67
68 if (use_uart) {
69 NS16550_t com_port = (NS16550_t)0x3f8;
70
71 while ((inb((ulong)&com_port->lsr) & UART_LSR_THRE) == 0)
72 ;
73 outb(ch, (ulong)&com_port->thr);
74 } else {
75 efi_putc(global_priv, ch);
76 }
77 }
78
puts(const char * str)79 void puts(const char *str)
80 {
81 while (*str)
82 putc(*str++);
83 }
84
_debug_uart_putc(int ch)85 static void _debug_uart_putc(int ch)
86 {
87 putc(ch);
88 }
89
90 DEBUG_UART_FUNCS
91
memcpy(void * dest,const void * src,size_t size)92 void *memcpy(void *dest, const void *src, size_t size)
93 {
94 unsigned char *dptr = dest;
95 const unsigned char *ptr = src;
96 const unsigned char *end = src + size;
97
98 while (ptr < end)
99 *dptr++ = *ptr++;
100
101 return dest;
102 }
103
memset(void * inptr,int ch,size_t size)104 void *memset(void *inptr, int ch, size_t size)
105 {
106 char *ptr = inptr;
107 char *end = ptr + size;
108
109 while (ptr < end)
110 *ptr++ = ch;
111
112 return ptr;
113 }
114
jump_to_uboot(ulong cs32,ulong addr,ulong info)115 static void jump_to_uboot(ulong cs32, ulong addr, ulong info)
116 {
117 #ifdef CONFIG_EFI_STUB_32BIT
118 /*
119 * U-Boot requires these parameters in registers, not on the stack.
120 * See _x86boot_start() for this code.
121 */
122 typedef void (*func_t)(int bist, int unused, ulong info)
123 __attribute__((regparm(3)));
124
125 ((func_t)addr)(0, 0, info);
126 #else
127 cpu_call32(cs32, CONFIG_SYS_TEXT_BASE, info);
128 #endif
129 }
130
131 #ifdef CONFIG_EFI_STUB_64BIT
get_gdt(struct desctab_info * info)132 static void get_gdt(struct desctab_info *info)
133 {
134 asm volatile ("sgdt %0" : : "m"(*info) : "memory");
135 }
136 #endif
137
read_cr3(void)138 static inline unsigned long read_cr3(void)
139 {
140 unsigned long val;
141
142 asm volatile("mov %%cr3,%0" : "=r" (val) : : "memory");
143 return val;
144 }
145
146 /**
147 * get_codeseg32() - Find the code segment to use for 32-bit code
148 *
149 * U-Boot only works in 32-bit mode at present, so when booting from 64-bit
150 * EFI we must first change to 32-bit mode. To do this we need to find the
151 * correct code segment to use (an entry in the Global Descriptor Table).
152 *
153 * @return code segment GDT offset, or 0 for 32-bit EFI, -ENOENT if not found
154 */
get_codeseg32(void)155 static int get_codeseg32(void)
156 {
157 int cs32 = 0;
158
159 #ifdef CONFIG_EFI_STUB_64BIT
160 struct desctab_info gdt;
161 uint64_t *ptr;
162 int i;
163
164 get_gdt(&gdt);
165 for (ptr = (uint64_t *)(unsigned long)gdt.addr, i = 0; i < gdt.limit;
166 i += 8, ptr++) {
167 uint64_t desc = *ptr;
168 uint64_t base, limit;
169
170 /*
171 * Check that the target U-Boot jump address is within the
172 * selector and that the selector is of the right type.
173 */
174 base = ((desc >> GDT_BASE_LOW_SHIFT) & GDT_BASE_LOW_MASK) |
175 ((desc >> GDT_BASE_HIGH_SHIFT) & GDT_BASE_HIGH_MASK)
176 << 16;
177 limit = ((desc >> GDT_LIMIT_LOW_SHIFT) & GDT_LIMIT_LOW_MASK) |
178 ((desc >> GDT_LIMIT_HIGH_SHIFT) & GDT_LIMIT_HIGH_MASK)
179 << 16;
180 base <<= 12; /* 4KB granularity */
181 limit <<= 12;
182 if ((desc & GDT_PRESENT) && (desc & GDT_NOTSYS) &&
183 !(desc & GDT_LONG) && (desc & GDT_4KB) &&
184 (desc & GDT_32BIT) && (desc & GDT_CODE) &&
185 CONFIG_SYS_TEXT_BASE > base &&
186 CONFIG_SYS_TEXT_BASE + CONFIG_SYS_MONITOR_LEN < limit
187 ) {
188 cs32 = i;
189 break;
190 }
191 }
192
193 #ifdef DEBUG
194 puts("\ngdt: ");
195 printhex8(gdt.limit);
196 puts(", addr: ");
197 printhex8(gdt.addr >> 32);
198 printhex8(gdt.addr);
199 for (i = 0; i < gdt.limit; i += 8) {
200 uint32_t *ptr = (uint32_t *)((unsigned long)gdt.addr + i);
201
202 puts("\n");
203 printhex2(i);
204 puts(": ");
205 printhex8(ptr[1]);
206 puts(" ");
207 printhex8(ptr[0]);
208 }
209 puts("\n ");
210 puts("32-bit code segment: ");
211 printhex2(cs32);
212 puts("\n ");
213
214 puts("page_table: ");
215 printhex8(read_cr3());
216 puts("\n ");
217 #endif
218 if (!cs32) {
219 puts("Can't find 32-bit code segment\n");
220 return -ENOENT;
221 }
222 #endif
223
224 return cs32;
225 }
226
setup_info_table(struct efi_priv * priv,int size)227 static int setup_info_table(struct efi_priv *priv, int size)
228 {
229 struct efi_info_hdr *info;
230 efi_status_t ret;
231
232 /* Get some memory for our info table */
233 priv->info_size = size;
234 info = efi_malloc(priv, priv->info_size, &ret);
235 if (ret) {
236 printhex2(ret);
237 puts(" No memory for info table: ");
238 return ret;
239 }
240
241 memset(info, '\0', sizeof(*info));
242 info->version = EFI_TABLE_VERSION;
243 info->hdr_size = sizeof(*info);
244 priv->info = info;
245 priv->next_hdr = (char *)info + info->hdr_size;
246
247 return 0;
248 }
249
add_entry_addr(struct efi_priv * priv,enum efi_entry_t type,void * ptr1,int size1,void * ptr2,int size2)250 static void add_entry_addr(struct efi_priv *priv, enum efi_entry_t type,
251 void *ptr1, int size1, void *ptr2, int size2)
252 {
253 struct efi_entry_hdr *hdr = priv->next_hdr;
254
255 hdr->type = type;
256 hdr->size = size1 + size2;
257 hdr->addr = 0;
258 hdr->link = ALIGN(sizeof(*hdr) + hdr->size, 16);
259 priv->next_hdr += hdr->link;
260 memcpy(hdr + 1, ptr1, size1);
261 memcpy((void *)(hdr + 1) + size1, ptr2, size2);
262 priv->info->total_size = (ulong)priv->next_hdr - (ulong)priv->info;
263 }
264
265 /**
266 * efi_main() - Start an EFI image
267 *
268 * This function is called by our EFI start-up code. It handles running
269 * U-Boot. If it returns, EFI will continue.
270 */
efi_main(efi_handle_t image,struct efi_system_table * sys_table)271 efi_status_t EFIAPI efi_main(efi_handle_t image,
272 struct efi_system_table *sys_table)
273 {
274 struct efi_priv local_priv, *priv = &local_priv;
275 struct efi_boot_services *boot = sys_table->boottime;
276 struct efi_mem_desc *desc;
277 struct efi_entry_memmap map;
278 struct efi_gop *gop;
279 struct efi_entry_gopmode mode;
280 struct efi_entry_systable table;
281 efi_guid_t efi_gop_guid = EFI_GOP_GUID;
282 efi_uintn_t key, desc_size, size;
283 efi_status_t ret;
284 u32 version;
285 int cs32;
286
287 ret = efi_init(priv, "Payload", image, sys_table);
288 if (ret) {
289 printhex2(ret);
290 puts(" efi_init() failed\n");
291 return ret;
292 }
293 global_priv = priv;
294
295 cs32 = get_codeseg32();
296 if (cs32 < 0)
297 return EFI_UNSUPPORTED;
298
299 /* Get the memory map so we can switch off EFI */
300 size = 0;
301 ret = boot->get_memory_map(&size, NULL, &key, &desc_size, &version);
302 if (ret != EFI_BUFFER_TOO_SMALL) {
303 printhex2(EFI_BITS_PER_LONG);
304 putc(' ');
305 printhex2(ret);
306 puts(" No memory map\n");
307 return ret;
308 }
309 size += 1024; /* Since doing a malloc() may change the memory map! */
310 desc = efi_malloc(priv, size, &ret);
311 if (!desc) {
312 printhex2(ret);
313 puts(" No memory for memory descriptor\n");
314 return ret;
315 }
316 ret = setup_info_table(priv, size + 128);
317 if (ret)
318 return ret;
319
320 ret = boot->locate_protocol(&efi_gop_guid, NULL, (void **)&gop);
321 if (ret) {
322 puts(" GOP unavailable\n");
323 } else {
324 mode.fb_base = gop->mode->fb_base;
325 mode.fb_size = gop->mode->fb_size;
326 mode.info_size = gop->mode->info_size;
327 add_entry_addr(priv, EFIET_GOP_MODE, &mode, sizeof(mode),
328 gop->mode->info,
329 sizeof(struct efi_gop_mode_info));
330 }
331
332 ret = boot->get_memory_map(&size, desc, &key, &desc_size, &version);
333 if (ret) {
334 printhex2(ret);
335 puts(" Can't get memory map\n");
336 return ret;
337 }
338
339 table.sys_table = (ulong)sys_table;
340 add_entry_addr(priv, EFIET_SYS_TABLE, &table, sizeof(table), NULL, 0);
341
342 ret = boot->exit_boot_services(image, key);
343 if (ret) {
344 /*
345 * Unfortunately it happens that we cannot exit boot services
346 * the first time. But the second time it work. I don't know
347 * why but this seems to be a repeatable problem. To get
348 * around it, just try again.
349 */
350 printhex2(ret);
351 puts(" Can't exit boot services\n");
352 size = sizeof(desc);
353 ret = boot->get_memory_map(&size, desc, &key, &desc_size,
354 &version);
355 if (ret) {
356 printhex2(ret);
357 puts(" Can't get memory map\n");
358 return ret;
359 }
360 ret = boot->exit_boot_services(image, key);
361 if (ret) {
362 printhex2(ret);
363 puts(" Can't exit boot services 2\n");
364 return ret;
365 }
366 }
367
368 /* The EFI UART won't work now, switch to a debug one */
369 use_uart = true;
370
371 map.version = version;
372 map.desc_size = desc_size;
373 add_entry_addr(priv, EFIET_MEMORY_MAP, &map, sizeof(map), desc, size);
374 add_entry_addr(priv, EFIET_END, NULL, 0, 0, 0);
375
376 memcpy((void *)CONFIG_SYS_TEXT_BASE, _binary_u_boot_bin_start,
377 (ulong)_binary_u_boot_bin_end -
378 (ulong)_binary_u_boot_bin_start);
379
380 #ifdef DEBUG
381 puts("EFI table at ");
382 printhex8((ulong)priv->info);
383 puts(" size ");
384 printhex8(priv->info->total_size);
385 #endif
386 putc('\n');
387 jump_to_uboot(cs32, CONFIG_SYS_TEXT_BASE, (ulong)priv->info);
388
389 return EFI_LOAD_ERROR;
390 }
391