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 <malloc.h>
18 #include <ns16550.h>
19 #include <asm/cpu.h>
20 #include <asm/io.h>
21 #include <linux/err.h>
22 #include <linux/types.h>
23
24 #ifndef CONFIG_X86
25 /*
26 * Problem areas:
27 * - putc() uses the ns16550 address directly and assumed I/O access. Many
28 * platforms will use memory access
29 * get_codeseg32() is only meaningful on x86
30 */
31 #error "This file needs to be ported for use on architectures"
32 #endif
33
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 struct efi_priv *priv = efi_get_priv();
66
67 if (ch == '\n')
68 putc('\r');
69
70 if (use_uart) {
71 struct ns16550 *com_port = (struct ns16550 *)0x3f8;
72
73 while ((inb((ulong)&com_port->lsr) & UART_LSR_THRE) == 0)
74 ;
75 outb(ch, (ulong)&com_port->thr);
76 } else {
77 efi_putc(priv, ch);
78 }
79 }
80
puts(const char * str)81 void puts(const char *str)
82 {
83 while (*str)
84 putc(*str++);
85 }
86
_debug_uart_putc(int ch)87 static void _debug_uart_putc(int ch)
88 {
89 putc(ch);
90 }
91
92 DEBUG_UART_FUNCS
93
memcpy(void * dest,const void * src,size_t size)94 void *memcpy(void *dest, const void *src, size_t size)
95 {
96 unsigned char *dptr = dest;
97 const unsigned char *ptr = src;
98 const unsigned char *end = src + size;
99
100 while (ptr < end)
101 *dptr++ = *ptr++;
102
103 return dest;
104 }
105
memset(void * inptr,int ch,size_t size)106 void *memset(void *inptr, int ch, size_t size)
107 {
108 char *ptr = inptr;
109 char *end = ptr + size;
110
111 while (ptr < end)
112 *ptr++ = ch;
113
114 return ptr;
115 }
116
jump_to_uboot(ulong cs32,ulong addr,ulong info)117 static void jump_to_uboot(ulong cs32, ulong addr, ulong info)
118 {
119 #ifdef CONFIG_EFI_STUB_32BIT
120 /*
121 * U-Boot requires these parameters in registers, not on the stack.
122 * See _x86boot_start() for this code.
123 */
124 typedef void (*func_t)(int bist, int unused, ulong info)
125 __attribute__((regparm(3)));
126
127 ((func_t)addr)(0, 0, info);
128 #else
129 cpu_call32(cs32, CONFIG_TEXT_BASE, info);
130 #endif
131 }
132
133 #ifdef CONFIG_EFI_STUB_64BIT
get_gdt(struct desctab_info * info)134 static void get_gdt(struct desctab_info *info)
135 {
136 asm volatile ("sgdt %0" : : "m"(*info) : "memory");
137 }
138 #endif
139
read_cr3(void)140 static inline unsigned long read_cr3(void)
141 {
142 unsigned long val;
143
144 asm volatile("mov %%cr3,%0" : "=r" (val) : : "memory");
145 return val;
146 }
147
148 /**
149 * get_codeseg32() - Find the code segment to use for 32-bit code
150 *
151 * U-Boot only works in 32-bit mode at present, so when booting from 64-bit
152 * EFI we must first change to 32-bit mode. To do this we need to find the
153 * correct code segment to use (an entry in the Global Descriptor Table).
154 *
155 * Return: code segment GDT offset, or 0 for 32-bit EFI, -ENOENT if not found
156 */
get_codeseg32(void)157 static int get_codeseg32(void)
158 {
159 int cs32 = 0;
160
161 #ifdef CONFIG_EFI_STUB_64BIT
162 struct desctab_info gdt;
163 uint64_t *ptr;
164 int i;
165
166 get_gdt(&gdt);
167 for (ptr = (uint64_t *)(unsigned long)gdt.addr, i = 0; i < gdt.limit;
168 i += 8, ptr++) {
169 uint64_t desc = *ptr;
170 uint64_t base, limit;
171
172 /*
173 * Check that the target U-Boot jump address is within the
174 * selector and that the selector is of the right type.
175 */
176 base = ((desc >> GDT_BASE_LOW_SHIFT) & GDT_BASE_LOW_MASK) |
177 ((desc >> GDT_BASE_HIGH_SHIFT) & GDT_BASE_HIGH_MASK)
178 << 16;
179 limit = ((desc >> GDT_LIMIT_LOW_SHIFT) & GDT_LIMIT_LOW_MASK) |
180 ((desc >> GDT_LIMIT_HIGH_SHIFT) & GDT_LIMIT_HIGH_MASK)
181 << 16;
182 base <<= 12; /* 4KB granularity */
183 limit <<= 12;
184 if ((desc & GDT_PRESENT) && (desc & GDT_NOTSYS) &&
185 !(desc & GDT_LONG) && (desc & GDT_4KB) &&
186 (desc & GDT_32BIT) && (desc & GDT_CODE) &&
187 CONFIG_TEXT_BASE > base &&
188 CONFIG_TEXT_BASE + CONFIG_SYS_MONITOR_LEN < limit
189 ) {
190 cs32 = i;
191 break;
192 }
193 }
194
195 #ifdef DEBUG
196 puts("\ngdt: ");
197 printhex8(gdt.limit);
198 puts(", addr: ");
199 printhex8(gdt.addr >> 32);
200 printhex8(gdt.addr);
201 for (i = 0; i < gdt.limit; i += 8) {
202 uint32_t *ptr = (uint32_t *)((unsigned long)gdt.addr + i);
203
204 puts("\n");
205 printhex2(i);
206 puts(": ");
207 printhex8(ptr[1]);
208 puts(" ");
209 printhex8(ptr[0]);
210 }
211 puts("\n ");
212 puts("32-bit code segment: ");
213 printhex2(cs32);
214 puts("\n ");
215
216 puts("page_table: ");
217 printhex8(read_cr3());
218 puts("\n ");
219 #endif
220 if (!cs32) {
221 puts("Can't find 32-bit code segment\n");
222 return -ENOENT;
223 }
224 #endif
225
226 return cs32;
227 }
228
229 /**
230 * setup_info_table() - sets up a table containing information from EFI
231 *
232 * We must call exit_boot_services() before jumping out of the stub into U-Boot
233 * proper, so that U-Boot has full control of peripherals, memory, etc.
234 *
235 * Once we do this, we cannot call any boot-services functions so we must find
236 * out everything we need to before doing that.
237 *
238 * Set up a struct efi_info_hdr table which can hold various records (e.g.
239 * struct efi_entry_memmap) with information obtained from EFI.
240 *
241 * @priv: Pointer to our private information which contains the list
242 * @size: Size of the table to allocate
243 * Return: 0 if OK, non-zero on error
244 */
setup_info_table(struct efi_priv * priv,int size)245 static int setup_info_table(struct efi_priv *priv, int size)
246 {
247 struct efi_info_hdr *info;
248 efi_status_t ret;
249
250 /* Get some memory for our info table */
251 priv->info_size = size;
252 info = efi_malloc(priv, priv->info_size, &ret);
253 if (ret) {
254 printhex2(ret);
255 puts(" No memory for info table: ");
256 return ret;
257 }
258
259 memset(info, '\0', sizeof(*info));
260 info->version = EFI_TABLE_VERSION;
261 info->hdr_size = sizeof(*info);
262 priv->info = info;
263 priv->next_hdr = (char *)info + info->hdr_size;
264
265 return 0;
266 }
267
268 /**
269 * add_entry_addr() - Add a new entry to the efi_info list
270 *
271 * This adds an entry, consisting of a tag and two lots of data. This avoids the
272 * caller having to coalesce the data first
273 *
274 * @priv: Pointer to our private information which contains the list
275 * @type: Type of the entry to add
276 * @ptr1: Pointer to first data block to add
277 * @size1: Size of first data block in bytes (can be 0)
278 * @ptr2: Pointer to second data block to add
279 * @size2: Size of second data block in bytes (can be 0)
280 */
add_entry_addr(struct efi_priv * priv,enum efi_entry_t type,void * ptr1,int size1,void * ptr2,int size2)281 static void add_entry_addr(struct efi_priv *priv, enum efi_entry_t type,
282 void *ptr1, int size1, void *ptr2, int size2)
283 {
284 struct efi_entry_hdr *hdr = priv->next_hdr;
285
286 hdr->type = type;
287 hdr->size = size1 + size2;
288 hdr->addr = 0;
289 hdr->link = ALIGN(sizeof(*hdr) + hdr->size, 16);
290 priv->next_hdr += hdr->link;
291 memcpy(hdr + 1, ptr1, size1);
292 memcpy((void *)(hdr + 1) + size1, ptr2, size2);
293 priv->info->total_size = (ulong)priv->next_hdr - (ulong)priv->info;
294 }
295
296 /**
297 * efi_main() - Start an EFI image
298 *
299 * This function is called by our EFI start-up code. It handles running
300 * U-Boot. If it returns, EFI will continue.
301 */
efi_main(efi_handle_t image,struct efi_system_table * sys_table)302 efi_status_t EFIAPI efi_main(efi_handle_t image,
303 struct efi_system_table *sys_table)
304 {
305 struct efi_priv local_priv, *priv = &local_priv;
306 struct efi_boot_services *boot = sys_table->boottime;
307 struct efi_entry_memmap map;
308 struct efi_gop *gop;
309 struct efi_entry_gopmode mode;
310 struct efi_entry_systable table;
311 efi_guid_t efi_gop_guid = EFI_GRAPHICS_OUTPUT_PROTOCOL_GUID;
312 efi_status_t ret;
313 int cs32;
314
315 ret = efi_init(priv, "Payload", image, sys_table);
316 if (ret) {
317 printhex2(ret);
318 puts(" efi_init() failed\n");
319 return ret;
320 }
321 efi_set_priv(priv);
322
323 cs32 = get_codeseg32();
324 if (cs32 < 0)
325 return EFI_UNSUPPORTED;
326
327 ret = efi_store_memory_map(priv);
328 if (ret)
329 return ret;
330
331 ret = setup_info_table(priv, priv->memmap_size + 128);
332 if (ret)
333 return ret;
334
335 ret = boot->locate_protocol(&efi_gop_guid, NULL, (void **)&gop);
336 if (ret) {
337 puts(" GOP unavailable\n");
338 } else {
339 mode.fb_base = gop->mode->fb_base;
340 mode.fb_size = gop->mode->fb_size;
341 mode.info_size = gop->mode->info_size;
342 add_entry_addr(priv, EFIET_GOP_MODE, &mode, sizeof(mode),
343 gop->mode->info,
344 sizeof(struct efi_gop_mode_info));
345 }
346
347 table.sys_table = (ulong)sys_table;
348 add_entry_addr(priv, EFIET_SYS_TABLE, &table, sizeof(table), NULL, 0);
349
350 ret = efi_call_exit_boot_services();
351 if (ret)
352 return ret;
353
354 /* The EFI UART won't work now, switch to a debug one */
355 use_uart = true;
356
357 map.version = priv->memmap_version;
358 map.desc_size = priv->memmap_desc_size;
359 add_entry_addr(priv, EFIET_MEMORY_MAP, &map, sizeof(map),
360 priv->memmap_desc, priv->memmap_size);
361 add_entry_addr(priv, EFIET_END, NULL, 0, 0, 0);
362
363 memcpy((void *)CONFIG_TEXT_BASE, _binary_u_boot_bin_start,
364 (ulong)_binary_u_boot_bin_end -
365 (ulong)_binary_u_boot_bin_start);
366
367 #ifdef DEBUG
368 puts("EFI table at ");
369 printhex8((ulong)priv->info);
370 puts(" size ");
371 printhex8(priv->info->total_size);
372 #endif
373 putc('\n');
374 jump_to_uboot(cs32, CONFIG_TEXT_BASE, (ulong)priv->info);
375
376 return EFI_LOAD_ERROR;
377 }
378