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 a
10 * 32-bit EFI application.
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)
69 NS16550_t com_port = (NS16550_t)0x3f8;
71 while ((inb((ulong)&com_port->lsr) & UART_LSR_THRE) == 0)
73 outb(ch, (ulong)&com_port->thr);
75 efi_putc(global_priv, ch);
81 void puts(const char *str)
87 static void _debug_uart_putc(int ch)
94 void *memcpy(void *dest, const void *src, size_t size)
96 unsigned char *dptr = dest;
97 const unsigned char *ptr = src;
98 const unsigned char *end = src + size;
106 void *memset(void *inptr, int ch, size_t size)
109 char *end = ptr + size;
117 static void jump_to_uboot(ulong cs32, ulong addr, ulong info)
119 #ifdef CONFIG_EFI_STUB_32BIT
121 * U-Boot requires these parameters in registers, not on the stack.
122 * See _x86boot_start() for this code.
124 typedef void (*func_t)(int bist, int unused, ulong info)
125 __attribute__((regparm(3)));
127 ((func_t)addr)(0, 0, info);
129 /* TODO: Implement this */
133 static void get_gdt(struct desctab_info *info)
135 asm volatile ("sgdt %0" : : "m"(*info) : "memory");
138 static inline unsigned long read_cr3(void)
142 asm volatile("mov %%cr3,%0" : "=r" (val) : : "memory");
147 * get_codeseg32() - Find the code segment to use for 32-bit code
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).
153 * @return code segment GDT offset, or 0 for 32-bit EFI, -ENOENT if not found
155 static int get_codeseg32(void)
159 /* TODO(sjg): Implement this for 64-bit mode */
163 static int setup_info_table(struct efi_priv *priv, int size)
165 struct efi_info_hdr *info;
168 /* Get some memory for our info table */
169 priv->info_size = size;
170 info = efi_malloc(priv, priv->info_size, &ret);
173 puts(" No memory for info table: ");
177 memset(info, '\0', sizeof(*info));
178 info->version = EFI_TABLE_VERSION;
179 info->hdr_size = sizeof(*info);
181 priv->next_hdr = (char *)info + info->hdr_size;
186 static void add_entry_addr(struct efi_priv *priv, enum efi_entry_t type,
187 void *ptr1, int size1, void *ptr2, int size2)
189 struct efi_entry_hdr *hdr = priv->next_hdr;
192 hdr->size = size1 + size2;
194 hdr->link = ALIGN(sizeof(*hdr) + hdr->size, 16);
195 priv->next_hdr += hdr->link;
196 memcpy(hdr + 1, ptr1, size1);
197 memcpy((void *)(hdr + 1) + size1, ptr2, size2);
198 priv->info->total_size = (ulong)priv->next_hdr - (ulong)priv->info;
202 * efi_main() - Start an EFI image
204 * This function is called by our EFI start-up code. It handles running
205 * U-Boot. If it returns, EFI will continue.
207 efi_status_t efi_main(efi_handle_t image, struct efi_system_table *sys_table)
209 struct efi_priv local_priv, *priv = &local_priv;
210 struct efi_boot_services *boot = sys_table->boottime;
211 struct efi_mem_desc *desc;
212 struct efi_entry_memmap map;
213 ulong key, desc_size, size;
218 ret = efi_init(priv, "Payload", image, sys_table);
220 printhex2(ret); puts(" efi_init() failed\n");
225 cs32 = get_codeseg32();
227 return EFI_UNSUPPORTED;
229 /* Get the memory map so we can switch off EFI */
231 ret = boot->get_memory_map(&size, NULL, &key, &desc_size, &version);
232 if (ret != EFI_BUFFER_TOO_SMALL) {
233 printhex2(BITS_PER_LONG);
235 puts(" No memory map\n");
238 size += 1024; /* Since doing a malloc() may change the memory map! */
239 desc = efi_malloc(priv, size, &ret);
242 puts(" No memory for memory descriptor: ");
245 ret = setup_info_table(priv, size + 128);
249 ret = boot->get_memory_map(&size, desc, &key, &desc_size, &version);
252 puts(" Can't get memory map\n");
256 ret = boot->exit_boot_services(image, key);
259 * Unfortunately it happens that we cannot exit boot services
260 * the first time. But the second time it work. I don't know
261 * why but this seems to be a repeatable problem. To get
262 * around it, just try again.
265 puts(" Can't exit boot services\n");
267 ret = boot->get_memory_map(&size, desc, &key, &desc_size,
271 puts(" Can't get memory map\n");
274 ret = boot->exit_boot_services(image, key);
277 puts(" Can't exit boot services 2\n");
282 map.version = version;
283 map.desc_size = desc_size;
284 add_entry_addr(priv, EFIET_MEMORY_MAP, &map, sizeof(map), desc, size);
285 add_entry_addr(priv, EFIET_END, NULL, 0, 0, 0);
287 /* The EFI UART won't work now, switch to a debug one */
290 memcpy((void *)CONFIG_SYS_TEXT_BASE, _binary_u_boot_dtb_bin_start,
291 (ulong)_binary_u_boot_dtb_bin_end -
292 (ulong)_binary_u_boot_dtb_bin_start);
295 puts("EFI table at ");
296 printhex8((ulong)priv->info);
298 printhex8(priv->info->total_size);
301 jump_to_uboot(cs32, CONFIG_SYS_TEXT_BASE, (ulong)priv->info);
303 return EFI_LOAD_ERROR;