1/* 2 * U-Boot - x86 Startup Code 3 * 4 * (C) Copyright 2008-2011 5 * Graeme Russ, <graeme.russ@gmail.com> 6 * 7 * (C) Copyright 2002 8 * Daniel Engström, Omicron Ceti AB, <daniel@omicron.se> 9 * 10 * SPDX-License-Identifier: GPL-2.0+ 11 */ 12 13#include <config.h> 14#include <asm/global_data.h> 15#include <asm/post.h> 16#include <asm/processor.h> 17#include <asm/processor-flags.h> 18#include <generated/generic-asm-offsets.h> 19#include <generated/asm-offsets.h> 20 21.section .text 22.code32 23.globl _start 24.type _start, @function 25.globl _x86boot_start 26_x86boot_start: 27 /* 28 * This is the fail-safe 32-bit bootstrap entry point. 29 * 30 * This code is used when booting from another boot loader like 31 * coreboot or EFI. So we repeat some of the same init found in 32 * start16. 33 */ 34 cli 35 cld 36 37 /* Turn off cache (this might require a 486-class CPU) */ 38 movl %cr0, %eax 39 orl $(X86_CR0_NW | X86_CR0_CD), %eax 40 movl %eax, %cr0 41 wbinvd 42 43 /* Tell 32-bit code it is being entered from an in-RAM copy */ 44 movl $GD_FLG_WARM_BOOT, %ebx 45 jmp 1f 46 47 /* Add a way for tools to discover the _start entry point */ 48 .align 4 49 .long 0x12345678 50_start: 51 /* 52 * This is the 32-bit cold-reset entry point, coming from start16. 53 * Set %ebx to GD_FLG_COLD_BOOT to indicate this. 54 */ 55 movl $GD_FLG_COLD_BOOT, %ebx 561: 57 /* Save BIST */ 58 movl %eax, %ebp 59 60 /* Load the segement registers to match the GDT loaded in start16.S */ 61 movl $(X86_GDT_ENTRY_32BIT_DS * X86_GDT_ENTRY_SIZE), %eax 62 movw %ax, %fs 63 movw %ax, %ds 64 movw %ax, %gs 65 movw %ax, %es 66 movw %ax, %ss 67 68 /* Clear the interrupt vectors */ 69 lidt blank_idt_ptr 70 71 /* 72 * Critical early platform init - generally not used, we prefer init 73 * to happen later when we have a console, in case something goes 74 * wrong. 75 */ 76 jmp early_board_init 77.globl early_board_init_ret 78early_board_init_ret: 79 post_code(POST_START) 80 81 /* Initialise Cache-As-RAM */ 82 jmp car_init 83.globl car_init_ret 84car_init_ret: 85#ifndef CONFIG_HAVE_FSP 86 /* 87 * We now have CONFIG_SYS_CAR_SIZE bytes of Cache-As-RAM (or SRAM, 88 * or fully initialised SDRAM - we really don't care which) 89 * starting at CONFIG_SYS_CAR_ADDR to be used as a temporary stack 90 * and early malloc() area. The MRC requires some space at the top. 91 * 92 * Stack grows down from top of CAR. We have: 93 * 94 * top-> CONFIG_SYS_CAR_ADDR + CONFIG_SYS_CAR_SIZE 95 * MRC area 96 * global_data 97 * x86 global descriptor table 98 * early malloc area 99 * stack 100 * bottom-> CONFIG_SYS_CAR_ADDR 101 */ 102 movl $(CONFIG_SYS_CAR_ADDR + CONFIG_SYS_CAR_SIZE - 4), %esp 103#ifdef CONFIG_DCACHE_RAM_MRC_VAR_SIZE 104 subl $CONFIG_DCACHE_RAM_MRC_VAR_SIZE, %esp 105#endif 106#else 107 /* 108 * When we get here after car_init(), esp points to a temporary stack 109 * and esi holds the HOB list address returned by the FSP. 110 */ 111#endif 112 113 /* Reserve space on stack for global data */ 114 subl $GENERATED_GBL_DATA_SIZE, %esp 115 116 /* Align global data to 16-byte boundary */ 117 andl $0xfffffff0, %esp 118 post_code(POST_START_STACK) 119 120 /* Zero the global data since it won't happen later */ 121 xorl %eax, %eax 122 movl $GENERATED_GBL_DATA_SIZE, %ecx 123 movl %esp, %edi 124 rep stosb 125 126#ifdef CONFIG_HAVE_FSP 127 test %esi, %esi 128 jz skip_hob 129 130 /* Store HOB list */ 131 movl %esp, %edx 132 addl $GD_HOB_LIST, %edx 133 movl %esi, (%edx) 134 135skip_hob: 136#endif 137 /* Setup first parameter to setup_gdt, pointer to global_data */ 138 movl %esp, %eax 139 140 /* Reserve space for global descriptor table */ 141 subl $X86_GDT_SIZE, %esp 142 143 /* Align temporary global descriptor table to 16-byte boundary */ 144 andl $0xfffffff0, %esp 145 movl %esp, %ecx 146 147#if defined(CONFIG_SYS_MALLOC_F_LEN) 148 /* Set up the pre-relocation malloc pool */ 149 subl $CONFIG_SYS_MALLOC_F_LEN, %esp 150 movl %eax, %edx 151 addl $GD_MALLOC_BASE, %edx 152 movl %esp, (%edx) 153#endif 154 /* Store BIST into global_data */ 155 movl %eax, %edx 156 addl $GD_BIST, %edx 157 movl %ebp, (%edx) 158 159 /* Set second parameter to setup_gdt() */ 160 movl %ecx, %edx 161 162 /* Setup global descriptor table so gd->xyz works */ 163 call setup_gdt 164 165 /* Set parameter to board_init_f() to boot flags */ 166 post_code(POST_START_DONE) 167 xorl %eax, %eax 168 169 /* Enter, U-Boot! */ 170 call board_init_f 171 172 /* indicate (lack of) progress */ 173 movw $0x85, %ax 174 jmp die 175 176.globl board_init_f_r_trampoline 177.type board_init_f_r_trampoline, @function 178board_init_f_r_trampoline: 179 /* 180 * SDRAM has been initialised, U-Boot code has been copied into 181 * RAM, BSS has been cleared and relocation adjustments have been 182 * made. It is now time to jump into the in-RAM copy of U-Boot 183 * 184 * %eax = Address of top of new stack 185 */ 186 187 /* Stack grows down from top of SDRAM */ 188 movl %eax, %esp 189 190 /* Reserve space on stack for global data */ 191 subl $GENERATED_GBL_DATA_SIZE, %esp 192 193 /* Align global data to 16-byte boundary */ 194 andl $0xfffffff0, %esp 195 196 /* Setup first parameter to memcpy() and setup_gdt() */ 197 movl %esp, %eax 198 199 /* Setup second parameter to memcpy() */ 200 fs movl 0, %edx 201 202 /* Set third parameter to memcpy() */ 203 movl $GENERATED_GBL_DATA_SIZE, %ecx 204 205 /* Copy global data from CAR to SDRAM stack */ 206 call memcpy 207 208 /* Reserve space for global descriptor table */ 209 subl $X86_GDT_SIZE, %esp 210 211 /* Align global descriptor table to 16-byte boundary */ 212 andl $0xfffffff0, %esp 213 214 /* Set second parameter to setup_gdt() */ 215 movl %esp, %edx 216 217 /* Setup global descriptor table so gd->xyz works */ 218 call setup_gdt 219 220 /* Set if we need to disable CAR */ 221.weak car_uninit 222 movl $car_uninit, %eax 223 cmpl $0, %eax 224 jz 1f 225 226 call car_uninit 2271: 228 /* Re-enter U-Boot by calling board_init_f_r() */ 229 call board_init_f_r 230 231die: 232 hlt 233 jmp die 234 hlt 235 236blank_idt_ptr: 237 .word 0 /* limit */ 238 .long 0 /* base */ 239 240 .p2align 2 /* force 4-byte alignment */ 241 242 /* Add a multiboot header so U-Boot can be loaded by GRUB2 */ 243multiboot_header: 244 /* magic */ 245 .long 0x1badb002 246 /* flags */ 247 .long (1 << 16) 248 /* checksum */ 249 .long -0x1BADB002 - (1 << 16) 250 /* header addr */ 251 .long multiboot_header - _x86boot_start + CONFIG_SYS_TEXT_BASE 252 /* load addr */ 253 .long CONFIG_SYS_TEXT_BASE 254 /* load end addr */ 255 .long 0 256 /* bss end addr */ 257 .long 0 258 /* entry addr */ 259 .long CONFIG_SYS_TEXT_BASE 260