arch/x86/cpu/start.S - github/trini/u-boot - Gitiles

 /*
  *  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>
  *
  * SPDX-License-Identifier:	GPL-2.0+
  */

 #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

 	/* 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)

 	/*
 	 * Debug UART is available here although it may not be plumbed out
 	 * to pins depending on the board. To use it:
 	 *
 	 * call  debug_uart_init
 	 * mov   $'a', %eax
 	 * call  printch
 	 */

 	/* 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
	/*
	* 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>
	*
	* SPDX-License-Identifier: GPL-2.0+
	*/

	#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

	/* 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)

	/*
	* Debug UART is available here although it may not be plumbed out
	* to pins depending on the board. To use it:
	*
	* call debug_uart_init
	* mov $'a', %eax
	* call printch
	*/

	/* 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