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