2 * Copyright (c) 2015 Google, Inc
4 * SPDX-License-Identifier: GPL-2.0+
6 * EFI information obtained here:
7 * http://wiki.phoenix.com/wiki/index.php/EFI_BOOT_SERVICES
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.
14 #include <debug_uart.h>
21 #include <linux/err.h>
22 #include <linux/types.h>
24 DECLARE_GLOBAL_DATA_PTR;
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
33 #error "This file needs to be ported for use on architectures"
36 static struct efi_priv *global_priv;
39 struct __packed desctab_info {
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
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.
62 void _debug_uart_init(void)
66 void putc(const char ch)
72 NS16550_t com_port = (NS16550_t)0x3f8;
74 while ((inb((ulong)&com_port->lsr) & UART_LSR_THRE) == 0)
76 outb(ch, (ulong)&com_port->thr);
78 efi_putc(global_priv, ch);
82 void puts(const char *str)
88 static void _debug_uart_putc(int ch)
95 void *memcpy(void *dest, const void *src, size_t size)
97 unsigned char *dptr = dest;
98 const unsigned char *ptr = src;
99 const unsigned char *end = src + size;
107 void *memset(void *inptr, int ch, size_t size)
110 char *end = ptr + size;
118 static void jump_to_uboot(ulong cs32, ulong addr, ulong info)
120 #ifdef CONFIG_EFI_STUB_32BIT
122 * U-Boot requires these parameters in registers, not on the stack.
123 * See _x86boot_start() for this code.
125 typedef void (*func_t)(int bist, int unused, ulong info)
126 __attribute__((regparm(3)));
128 ((func_t)addr)(0, 0, info);
130 cpu_call32(cs32, CONFIG_SYS_TEXT_BASE, info);
134 #ifdef CONFIG_EFI_STUB_64BIT
135 static void get_gdt(struct desctab_info *info)
137 asm volatile ("sgdt %0" : : "m"(*info) : "memory");
141 static inline unsigned long read_cr3(void)
145 asm volatile("mov %%cr3,%0" : "=r" (val) : : "memory");
150 * get_codeseg32() - Find the code segment to use for 32-bit code
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).
156 * @return code segment GDT offset, or 0 for 32-bit EFI, -ENOENT if not found
158 static int get_codeseg32(void)
162 #ifdef CONFIG_EFI_STUB_64BIT
163 struct desctab_info gdt;
168 for (ptr = (uint64_t *)(unsigned long)gdt.addr, i = 0; i < gdt.limit;
170 uint64_t desc = *ptr;
171 uint64_t base, limit;
174 * Check that the target U-Boot jump address is within the
175 * selector and that the selector is of the right type.
177 base = ((desc >> GDT_BASE_LOW_SHIFT) & GDT_BASE_LOW_MASK) |
178 ((desc >> GDT_BASE_HIGH_SHIFT) & GDT_BASE_HIGH_MASK)
180 limit = ((desc >> GDT_LIMIT_LOW_SHIFT) & GDT_LIMIT_LOW_MASK) |
181 ((desc >> GDT_LIMIT_HIGH_SHIFT) & GDT_LIMIT_HIGH_MASK)
183 base <<= 12; /* 4KB granularity */
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
198 printhex8(gdt.limit);
200 printhex8(gdt.addr >> 32);
202 for (i = 0; i < gdt.limit; i += 8) {
203 uint32_t *ptr = (uint32_t *)((unsigned long)gdt.addr + i);
213 puts("32-bit code segment: ");
217 puts("page_table: ");
218 printhex8(read_cr3());
222 puts("Can't find 32-bit code segment\n");
230 static int setup_info_table(struct efi_priv *priv, int size)
232 struct efi_info_hdr *info;
235 /* Get some memory for our info table */
236 priv->info_size = size;
237 info = efi_malloc(priv, priv->info_size, &ret);
240 puts(" No memory for info table: ");
244 memset(info, '\0', sizeof(*info));
245 info->version = EFI_TABLE_VERSION;
246 info->hdr_size = sizeof(*info);
248 priv->next_hdr = (char *)info + info->hdr_size;
253 static void add_entry_addr(struct efi_priv *priv, enum efi_entry_t type,
254 void *ptr1, int size1, void *ptr2, int size2)
256 struct efi_entry_hdr *hdr = priv->next_hdr;
259 hdr->size = size1 + size2;
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;
269 * efi_main() - Start an EFI image
271 * This function is called by our EFI start-up code. It handles running
272 * U-Boot. If it returns, EFI will continue.
274 efi_status_t efi_main(efi_handle_t image, struct efi_system_table *sys_table)
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 efi_uintn_t key, desc_size, size;
285 ret = efi_init(priv, "Payload", image, sys_table);
287 printhex2(ret); puts(" efi_init() failed\n");
292 cs32 = get_codeseg32();
294 return EFI_UNSUPPORTED;
296 /* Get the memory map so we can switch off EFI */
298 ret = boot->get_memory_map(&size, NULL, &key, &desc_size, &version);
299 if (ret != EFI_BUFFER_TOO_SMALL) {
300 printhex2(BITS_PER_LONG);
302 puts(" No memory map\n");
305 size += 1024; /* Since doing a malloc() may change the memory map! */
306 desc = efi_malloc(priv, size, &ret);
309 puts(" No memory for memory descriptor: ");
312 ret = setup_info_table(priv, size + 128);
316 ret = boot->get_memory_map(&size, desc, &key, &desc_size, &version);
319 puts(" Can't get memory map\n");
323 ret = boot->exit_boot_services(image, key);
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.
332 puts(" Can't exit boot services\n");
334 ret = boot->get_memory_map(&size, desc, &key, &desc_size,
338 puts(" Can't get memory map\n");
341 ret = boot->exit_boot_services(image, key);
344 puts(" Can't exit boot services 2\n");
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);
354 /* The EFI UART won't work now, switch to a debug one */
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);
362 puts("EFI table at ");
363 printhex8((ulong)priv->info);
365 printhex8(priv->info->total_size);
368 jump_to_uboot(cs32, CONFIG_SYS_TEXT_BASE, (ulong)priv->info);
370 return EFI_LOAD_ERROR;