| /* SPDX-License-Identifier: GPL-2.0+ */ |
| /* |
| * U-Boot - x86 Startup Code |
| * |
| * (C) Copyright 2008-2011 |
| * Graeme Russ, <graeme.russ@gmail.com> |
| * |
| * (C) Copyright 2002 |
| * Daniel Engström, Omicron Ceti AB, <daniel@omicron.se> |
| */ |
| |
| #include <config.h> |
| #include <asm/global_data.h> |
| #include <asm/post.h> |
| #include <asm/processor.h> |
| #include <asm/processor-flags.h> |
| #include <generated/generic-asm-offsets.h> |
| #include <generated/asm-offsets.h> |
| |
| .section .text |
| .code32 |
| .globl _start |
| .type _start, @function |
| .globl _x86boot_start |
| _x86boot_start: |
| /* |
| * This is the fail-safe 32-bit bootstrap entry point. |
| * |
| * This code is used when booting from another boot loader like |
| * coreboot or EFI. So we repeat some of the same init found in |
| * start16. |
| */ |
| cli |
| cld |
| |
| /* Turn off cache (this might require a 486-class CPU) */ |
| movl %cr0, %eax |
| orl $(X86_CR0_NW | X86_CR0_CD), %eax |
| movl %eax, %cr0 |
| wbinvd |
| |
| /* Tell 32-bit code it is being entered from an in-RAM copy */ |
| movl $GD_FLG_WARM_BOOT, %ebx |
| |
| /* |
| * Zero the BIST (Built-In Self Test) value since we don't have it. |
| * It must be 0 or the previous loader would have reported an error. |
| */ |
| movl $0, %ebp |
| |
| jmp 1f |
| |
| /* Add a way for tools to discover the _start entry point */ |
| .align 4 |
| .long 0x12345678 |
| _start: |
| /* |
| * This is the 32-bit cold-reset entry point, coming from start16. |
| * Set %ebx to GD_FLG_COLD_BOOT to indicate this. |
| */ |
| movl $GD_FLG_COLD_BOOT, %ebx |
| |
| /* Save BIST */ |
| movl %eax, %ebp |
| 1: |
| |
| /* Save table pointer */ |
| movl %ecx, %esi |
| |
| #ifdef CONFIG_X86_LOAD_FROM_32_BIT |
| lgdt gdt_ptr2 |
| #endif |
| |
| /* Load the segement registers to match the GDT loaded in start16.S */ |
| movl $(X86_GDT_ENTRY_32BIT_DS * X86_GDT_ENTRY_SIZE), %eax |
| movw %ax, %fs |
| movw %ax, %ds |
| movw %ax, %gs |
| movw %ax, %es |
| movw %ax, %ss |
| |
| /* Clear the interrupt vectors */ |
| lidt blank_idt_ptr |
| |
| /* |
| * Critical early platform init - generally not used, we prefer init |
| * to happen later when we have a console, in case something goes |
| * wrong. |
| */ |
| jmp early_board_init |
| .globl early_board_init_ret |
| early_board_init_ret: |
| post_code(POST_START) |
| |
| /* Initialise Cache-As-RAM */ |
| jmp car_init |
| .globl car_init_ret |
| car_init_ret: |
| #ifndef CONFIG_HAVE_FSP |
| /* |
| * We now have CONFIG_SYS_CAR_SIZE bytes of Cache-As-RAM (or SRAM, |
| * or fully initialised SDRAM - we really don't care which) |
| * starting at CONFIG_SYS_CAR_ADDR to be used as a temporary stack |
| * and early malloc() area. The MRC requires some space at the top. |
| * |
| * Stack grows down from top of CAR. We have: |
| * |
| * top-> CONFIG_SYS_CAR_ADDR + CONFIG_SYS_CAR_SIZE |
| * MRC area |
| * global_data with x86 global descriptor table |
| * early malloc area |
| * stack |
| * bottom-> CONFIG_SYS_CAR_ADDR |
| */ |
| movl $(CONFIG_SYS_CAR_ADDR + CONFIG_SYS_CAR_SIZE - 4), %esp |
| #ifdef CONFIG_DCACHE_RAM_MRC_VAR_SIZE |
| subl $CONFIG_DCACHE_RAM_MRC_VAR_SIZE, %esp |
| #endif |
| #else |
| /* |
| * U-Boot enters here twice. For the first time it comes from |
| * car_init_done() with esp points to a temporary stack and esi |
| * set to zero. For the second time it comes from fsp_init_done() |
| * with esi holding the HOB list address returned by the FSP. |
| */ |
| #endif |
| /* Set up global data */ |
| mov %esp, %eax |
| call board_init_f_alloc_reserve |
| mov %eax, %esp |
| call board_init_f_init_reserve |
| |
| #ifdef CONFIG_DEBUG_UART |
| call debug_uart_init |
| #endif |
| |
| /* Get address of global_data */ |
| mov %fs:0, %edx |
| #ifdef CONFIG_HAVE_FSP |
| /* Store the HOB list if we have one */ |
| test %esi, %esi |
| jz skip_hob |
| movl %esi, GD_HOB_LIST(%edx) |
| |
| /* |
| * After fsp_init() returns, the stack has already been switched to a |
| * place within system memory as defined by CONFIG_FSP_TEMP_RAM_ADDR. |
| * Enlarge the size of malloc() pool before relocation since we have |
| * plenty of memory now. |
| */ |
| subl $CONFIG_FSP_SYS_MALLOC_F_LEN, %esp |
| movl %esp, GD_MALLOC_BASE(%edx) |
| skip_hob: |
| #else |
| /* Store table pointer */ |
| movl %esi, GD_TABLE(%edx) |
| #endif |
| /* Store BIST */ |
| movl %ebp, GD_BIST(%edx) |
| |
| /* Set parameter to board_init_f() to boot flags */ |
| post_code(POST_START_DONE) |
| xorl %eax, %eax |
| |
| /* Enter, U-Boot! */ |
| call board_init_f |
| |
| /* indicate (lack of) progress */ |
| movw $0x85, %ax |
| jmp die |
| |
| .globl board_init_f_r_trampoline |
| .type board_init_f_r_trampoline, @function |
| board_init_f_r_trampoline: |
| /* |
| * SDRAM has been initialised, U-Boot code has been copied into |
| * RAM, BSS has been cleared and relocation adjustments have been |
| * made. It is now time to jump into the in-RAM copy of U-Boot |
| * |
| * %eax = Address of top of new stack |
| */ |
| |
| /* Stack grows down from top of SDRAM */ |
| movl %eax, %esp |
| |
| /* See if we need to disable CAR */ |
| .weak car_uninit |
| movl $car_uninit, %eax |
| cmpl $0, %eax |
| jz 1f |
| |
| call car_uninit |
| 1: |
| /* Re-enter U-Boot by calling board_init_f_r() */ |
| call board_init_f_r |
| |
| die: |
| hlt |
| jmp die |
| hlt |
| |
| blank_idt_ptr: |
| .word 0 /* limit */ |
| .long 0 /* base */ |
| |
| .p2align 2 /* force 4-byte alignment */ |
| |
| /* Add a multiboot header so U-Boot can be loaded by GRUB2 */ |
| multiboot_header: |
| /* magic */ |
| .long 0x1badb002 |
| /* flags */ |
| .long (1 << 16) |
| /* checksum */ |
| .long -0x1BADB002 - (1 << 16) |
| /* header addr */ |
| .long multiboot_header - _x86boot_start + CONFIG_SYS_TEXT_BASE |
| /* load addr */ |
| .long CONFIG_SYS_TEXT_BASE |
| /* load end addr */ |
| .long 0 |
| /* bss end addr */ |
| .long 0 |
| /* entry addr */ |
| .long CONFIG_SYS_TEXT_BASE |
| |
| #ifdef CONFIG_X86_LOAD_FROM_32_BIT |
| /* |
| * The following Global Descriptor Table is just enough to get us into |
| * 'Flat Protected Mode' - It will be discarded as soon as the final |
| * GDT is setup in a safe location in RAM |
| */ |
| gdt_ptr2: |
| .word 0x1f /* limit (31 bytes = 4 GDT entries - 1) */ |
| .long gdt_rom2 /* base */ |
| |
| /* Some CPUs are picky about GDT alignment... */ |
| .align 16 |
| .globl gdt_rom2 |
| gdt_rom2: |
| /* |
| * The GDT table ... |
| * |
| * Selector Type |
| * 0x00 NULL |
| * 0x08 Unused |
| * 0x10 32bit code |
| * 0x18 32bit data/stack |
| */ |
| /* The NULL Desciptor - Mandatory */ |
| .word 0x0000 /* limit_low */ |
| .word 0x0000 /* base_low */ |
| .byte 0x00 /* base_middle */ |
| .byte 0x00 /* access */ |
| .byte 0x00 /* flags + limit_high */ |
| .byte 0x00 /* base_high */ |
| |
| /* Unused Desciptor - (matches Linux) */ |
| .word 0x0000 /* limit_low */ |
| .word 0x0000 /* base_low */ |
| .byte 0x00 /* base_middle */ |
| .byte 0x00 /* access */ |
| .byte 0x00 /* flags + limit_high */ |
| .byte 0x00 /* base_high */ |
| |
| /* |
| * The Code Segment Descriptor: |
| * - Base = 0x00000000 |
| * - Size = 4GB |
| * - Access = Present, Ring 0, Exec (Code), Readable |
| * - Flags = 4kB Granularity, 32-bit |
| */ |
| .word 0xffff /* limit_low */ |
| .word 0x0000 /* base_low */ |
| .byte 0x00 /* base_middle */ |
| .byte 0x9b /* access */ |
| .byte 0xcf /* flags + limit_high */ |
| .byte 0x00 /* base_high */ |
| |
| /* |
| * The Data Segment Descriptor: |
| * - Base = 0x00000000 |
| * - Size = 4GB |
| * - Access = Present, Ring 0, Non-Exec (Data), Writable |
| * - Flags = 4kB Granularity, 32-bit |
| */ |
| .word 0xffff /* limit_low */ |
| .word 0x0000 /* base_low */ |
| .byte 0x00 /* base_middle */ |
| .byte 0x93 /* access */ |
| .byte 0xcf /* flags + limit_high */ |
| .byte 0x00 /* base_high */ |
| #endif |