/* * U-Boot - x86 Startup Code * * (C) Copyright 2008-2011 * Graeme Russ, * * (C) Copyright 2002 * Daniel Engström, Omicron Ceti AB, * * SPDX-License-Identifier: GPL-2.0+ */ #include #include #include #include #include #include #include .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 /* 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 * 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 /* * When we get here after car_init(), esp points to a temporary stack * and esi holds the HOB list address returned by the FSP. */ #endif /* Reserve space on stack for global data */ subl $GENERATED_GBL_DATA_SIZE, %esp /* Align global data to 16-byte boundary */ andl $0xfffffff0, %esp post_code(POST_START_STACK) /* Zero the global data since it won't happen later */ xorl %eax, %eax movl $GENERATED_GBL_DATA_SIZE, %ecx movl %esp, %edi rep stosb #ifdef CONFIG_HAVE_FSP test %esi, %esi jz skip_hob /* Store HOB list */ movl %esp, %edx addl $GD_HOB_LIST, %edx movl %esi, (%edx) skip_hob: #else /* Store table pointer */ movl %esp, %edx addl $GD_TABLE, %edx movl %esi, (%edx) #endif /* Setup first parameter to setup_gdt, pointer to global_data */ movl %esp, %eax /* Reserve space for global descriptor table */ subl $X86_GDT_SIZE, %esp /* Align temporary global descriptor table to 16-byte boundary */ andl $0xfffffff0, %esp movl %esp, %ecx #if defined(CONFIG_SYS_MALLOC_F_LEN) /* Set up the pre-relocation malloc pool */ subl $CONFIG_SYS_MALLOC_F_LEN, %esp movl %eax, %edx addl $GD_MALLOC_BASE, %edx movl %esp, (%edx) #endif /* Store BIST into global_data */ movl %eax, %edx addl $GD_BIST, %edx movl %ebp, (%edx) /* Set second parameter to setup_gdt() */ movl %ecx, %edx /* Setup global descriptor table so gd->xyz works */ call setup_gdt /* 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 /* Reserve space on stack for global data */ subl $GENERATED_GBL_DATA_SIZE, %esp /* Align global data to 16-byte boundary */ andl $0xfffffff0, %esp /* Setup first parameter to memcpy() and setup_gdt() */ movl %esp, %eax /* Setup second parameter to memcpy() */ fs movl 0, %edx /* Set third parameter to memcpy() */ movl $GENERATED_GBL_DATA_SIZE, %ecx /* Copy global data from CAR to SDRAM stack */ call memcpy /* Reserve space for global descriptor table */ subl $X86_GDT_SIZE, %esp /* Align global descriptor table to 16-byte boundary */ andl $0xfffffff0, %esp /* Set second parameter to setup_gdt() */ movl %esp, %edx /* Setup global descriptor table so gd->xyz works */ call setup_gdt /* Set 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