Freescale u-boot repository
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/*
* Copyright (c) 2015 Google, Inc
*
* SPDX-License-Identifier: GPL-2.0+
*
* EFI information obtained here:
* http://wiki.phoenix.com/wiki/index.php/EFI_BOOT_SERVICES
*
* Loads a payload (U-Boot) within the EFI environment. This is built as an
* EFI application. It can be built either in 32-bit or 64-bit mode.
*/
#include <common.h>
#include <debug_uart.h>
#include <efi.h>
#include <efi_api.h>
#include <errno.h>
#include <ns16550.h>
#include <asm/cpu.h>
#include <asm/io.h>
#include <linux/err.h>
#include <linux/types.h>
DECLARE_GLOBAL_DATA_PTR;
#ifndef CONFIG_X86
/*
* Problem areas:
* - putc() uses the ns16550 address directly and assumed I/O access. Many
* platforms will use memory access
* get_codeseg32() is only meaningful on x86
*/
#error "This file needs to be ported for use on architectures"
#endif
static struct efi_priv *global_priv;
static bool use_uart;
struct __packed desctab_info {
uint16_t limit;
uint64_t addr;
uint16_t pad;
};
/*
* EFI uses Unicode and we don't. The easiest way to get a sensible output
* function is to use the U-Boot debug UART. We use EFI's console output
* function where available, and assume the built-in UART after that. We rely
* on EFI to set up the UART for us and just bring in the functions here.
* This last bit is a bit icky, but it's only for debugging anyway. We could
* build in ns16550.c with some effort, but this is a payload loader after
* all.
*
* Note: We avoid using printf() so we don't need to bring in lib/vsprintf.c.
* That would require some refactoring since we already build this for U-Boot.
* Building an EFI shared library version would have to be a separate stem.
* That might push us to using the SPL framework to build this stub. However
* that would involve a round of EFI-specific changes in SPL. Worth
* considering if we start needing more U-Boot functionality. Note that we
* could then move get_codeseg32() to arch/x86/cpu/cpu.c.
*/
void _debug_uart_init(void)
{
}
void putc(const char ch)
{
if (use_uart) {
NS16550_t com_port = (NS16550_t)0x3f8;
while ((inb((ulong)&com_port->lsr) & UART_LSR_THRE) == 0)
;
outb(ch, (ulong)&com_port->thr);
} else {
efi_putc(global_priv, ch);
}
if (ch == '\n')
putc('\r');
}
void puts(const char *str)
{
while (*str)
putc(*str++);
}
static void _debug_uart_putc(int ch)
{
putc(ch);
}
DEBUG_UART_FUNCS
void *memcpy(void *dest, const void *src, size_t size)
{
unsigned char *dptr = dest;
const unsigned char *ptr = src;
const unsigned char *end = src + size;
while (ptr < end)
*dptr++ = *ptr++;
return dest;
}
void *memset(void *inptr, int ch, size_t size)
{
char *ptr = inptr;
char *end = ptr + size;
while (ptr < end)
*ptr++ = ch;
return ptr;
}
static void jump_to_uboot(ulong cs32, ulong addr, ulong info)
{
#ifdef CONFIG_EFI_STUB_32BIT
/*
* U-Boot requires these parameters in registers, not on the stack.
* See _x86boot_start() for this code.
*/
typedef void (*func_t)(int bist, int unused, ulong info)
__attribute__((regparm(3)));
((func_t)addr)(0, 0, info);
#else
cpu_call32(cs32, CONFIG_SYS_TEXT_BASE, info);
#endif
}
#ifdef CONFIG_EFI_STUB_64BIT
static void get_gdt(struct desctab_info *info)
{
asm volatile ("sgdt %0" : : "m"(*info) : "memory");
}
#endif
static inline unsigned long read_cr3(void)
{
unsigned long val;
asm volatile("mov %%cr3,%0" : "=r" (val) : : "memory");
return val;
}
/**
* get_codeseg32() - Find the code segment to use for 32-bit code
*
* U-Boot only works in 32-bit mode at present, so when booting from 64-bit
* EFI we must first change to 32-bit mode. To do this we need to find the
* correct code segment to use (an entry in the Global Descriptor Table).
*
* @return code segment GDT offset, or 0 for 32-bit EFI, -ENOENT if not found
*/
static int get_codeseg32(void)
{
int cs32 = 0;
#ifdef CONFIG_EFI_STUB_64BIT
struct desctab_info gdt;
uint64_t *ptr;
int i;
get_gdt(&gdt);
for (ptr = (uint64_t *)(unsigned long)gdt.addr, i = 0; i < gdt.limit;
i += 8, ptr++) {
uint64_t desc = *ptr;
uint64_t base, limit;
/*
* Check that the target U-Boot jump address is within the
* selector and that the selector is of the right type.
*/
base = ((desc >> GDT_BASE_LOW_SHIFT) & GDT_BASE_LOW_MASK) |
((desc >> GDT_BASE_HIGH_SHIFT) & GDT_BASE_HIGH_MASK)
<< 16;
limit = ((desc >> GDT_LIMIT_LOW_SHIFT) & GDT_LIMIT_LOW_MASK) |
((desc >> GDT_LIMIT_HIGH_SHIFT) & GDT_LIMIT_HIGH_MASK)
<< 16;
base <<= 12; /* 4KB granularity */
limit <<= 12;
if ((desc & GDT_PRESENT) && (desc && GDT_NOTSYS) &&
!(desc & GDT_LONG) && (desc & GDT_4KB) &&
(desc & GDT_32BIT) && (desc & GDT_CODE) &&
CONFIG_SYS_TEXT_BASE > base &&
CONFIG_SYS_TEXT_BASE + CONFIG_SYS_MONITOR_LEN < limit
) {
cs32 = i;
break;
}
}
#ifdef DEBUG
puts("\ngdt: ");
printhex8(gdt.limit);
puts(", addr: ");
printhex8(gdt.addr >> 32);
printhex8(gdt.addr);
for (i = 0; i < gdt.limit; i += 8) {
uint32_t *ptr = (uint32_t *)((unsigned long)gdt.addr + i);
puts("\n");
printhex2(i);
puts(": ");
printhex8(ptr[1]);
puts(" ");
printhex8(ptr[0]);
}
puts("\n ");
puts("32-bit code segment: ");
printhex2(cs32);
puts("\n ");
puts("page_table: ");
printhex8(read_cr3());
puts("\n ");
#endif
if (!cs32) {
puts("Can't find 32-bit code segment\n");
return -ENOENT;
}
#endif
return cs32;
}
static int setup_info_table(struct efi_priv *priv, int size)
{
struct efi_info_hdr *info;
efi_status_t ret;
/* Get some memory for our info table */
priv->info_size = size;
info = efi_malloc(priv, priv->info_size, &ret);
if (ret) {
printhex2(ret);
puts(" No memory for info table: ");
return ret;
}
memset(info, '\0', sizeof(*info));
info->version = EFI_TABLE_VERSION;
info->hdr_size = sizeof(*info);
priv->info = info;
priv->next_hdr = (char *)info + info->hdr_size;
return 0;
}
static void add_entry_addr(struct efi_priv *priv, enum efi_entry_t type,
void *ptr1, int size1, void *ptr2, int size2)
{
struct efi_entry_hdr *hdr = priv->next_hdr;
hdr->type = type;
hdr->size = size1 + size2;
hdr->addr = 0;
hdr->link = ALIGN(sizeof(*hdr) + hdr->size, 16);
priv->next_hdr += hdr->link;
memcpy(hdr + 1, ptr1, size1);
memcpy((void *)(hdr + 1) + size1, ptr2, size2);
priv->info->total_size = (ulong)priv->next_hdr - (ulong)priv->info;
}
/**
* efi_main() - Start an EFI image
*
* This function is called by our EFI start-up code. It handles running
* U-Boot. If it returns, EFI will continue.
*/
efi_status_t efi_main(efi_handle_t image, struct efi_system_table *sys_table)
{
struct efi_priv local_priv, *priv = &local_priv;
struct efi_boot_services *boot = sys_table->boottime;
struct efi_mem_desc *desc;
struct efi_entry_memmap map;
ulong key, desc_size, size;
efi_status_t ret;
u32 version;
int cs32;
ret = efi_init(priv, "Payload", image, sys_table);
if (ret) {
printhex2(ret); puts(" efi_init() failed\n");
return ret;
}
global_priv = priv;
cs32 = get_codeseg32();
if (cs32 < 0)
return EFI_UNSUPPORTED;
/* Get the memory map so we can switch off EFI */
size = 0;
ret = boot->get_memory_map(&size, NULL, &key, &desc_size, &version);
if (ret != EFI_BUFFER_TOO_SMALL) {
printhex2(BITS_PER_LONG);
printhex2(ret);
puts(" No memory map\n");
return ret;
}
size += 1024; /* Since doing a malloc() may change the memory map! */
desc = efi_malloc(priv, size, &ret);
if (!desc) {
printhex2(ret);
puts(" No memory for memory descriptor: ");
return ret;
}
ret = setup_info_table(priv, size + 128);
if (ret)
return ret;
ret = boot->get_memory_map(&size, desc, &key, &desc_size, &version);
if (ret) {
printhex2(ret);
puts(" Can't get memory map\n");
return ret;
}
ret = boot->exit_boot_services(image, key);
if (ret) {
/*
* Unfortunately it happens that we cannot exit boot services
* the first time. But the second time it work. I don't know
* why but this seems to be a repeatable problem. To get
* around it, just try again.
*/
printhex2(ret);
puts(" Can't exit boot services\n");
size = sizeof(desc);
ret = boot->get_memory_map(&size, desc, &key, &desc_size,
&version);
if (ret) {
printhex2(ret);
puts(" Can't get memory map\n");
return ret;
}
ret = boot->exit_boot_services(image, key);
if (ret) {
printhex2(ret);
puts(" Can't exit boot services 2\n");
return ret;
}
}
map.version = version;
map.desc_size = desc_size;
add_entry_addr(priv, EFIET_MEMORY_MAP, &map, sizeof(map), desc, size);
add_entry_addr(priv, EFIET_END, NULL, 0, 0, 0);
/* The EFI UART won't work now, switch to a debug one */
use_uart = true;
memcpy((void *)CONFIG_SYS_TEXT_BASE, _binary_u_boot_dtb_bin_start,
(ulong)_binary_u_boot_dtb_bin_end -
(ulong)_binary_u_boot_dtb_bin_start);
#ifdef DEBUG
puts("EFI table at ");
printhex8((ulong)priv->info);
puts(" size ");
printhex8(priv->info->total_size);
#endif
putc('\n');
jump_to_uboot(cs32, CONFIG_SYS_TEXT_BASE, (ulong)priv->info);
return EFI_LOAD_ERROR;
}