This adds a wake up stub before jumping to OS wake up vector. Signed-off-by: Bin Meng <bmeng.cn@gmail.com> Reviewed-by: Simon Glass <sjg@chromium.org> Tested-by: Stefan Roese <sr@denx.de>master
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/* |
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* Copyright (C) 2017, Bin Meng <bmeng.cn@gmail.com>
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* |
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* From coreboot src/arch/x86/wakeup.S |
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* |
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* SPDX-License-Identifier: GPL-2.0+ |
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*/ |
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#include <asm/acpi_s3.h> |
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#include <asm/processor.h> |
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#include <asm/processor-flags.h> |
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#define RELOCATED(x) ((x) - __wakeup + WAKEUP_BASE) |
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#define CODE_SEG (X86_GDT_ENTRY_16BIT_CS * X86_GDT_ENTRY_SIZE) |
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#define DATA_SEG (X86_GDT_ENTRY_16BIT_DS * X86_GDT_ENTRY_SIZE) |
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.code32 |
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.globl __wakeup
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__wakeup: |
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/* First prepare the jmp to the resume vector */ |
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mov 0x4(%esp), %eax /* vector */ |
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/* last 4 bits of linear addr are taken as offset */ |
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andw $0x0f, %ax |
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movw %ax, (__wakeup_offset) |
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mov 0x4(%esp), %eax |
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/* the rest is taken as segment */ |
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shr $4, %eax |
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movw %ax, (__wakeup_segment) |
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/* Activate the right segment descriptor real mode */ |
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ljmp $CODE_SEG, $RELOCATED(1f) |
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1: |
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/* 16 bit code from here on... */ |
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.code16 |
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/* |
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* Load the segment registers w/ properly configured segment |
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* descriptors. They will retain these configurations (limits, |
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* writability, etc.) once protected mode is turned off. |
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*/ |
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mov $DATA_SEG, %ax |
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mov %ax, %ds |
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mov %ax, %es |
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mov %ax, %fs |
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mov %ax, %gs |
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mov %ax, %ss |
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/* Turn off protection */ |
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movl %cr0, %eax |
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andl $~X86_CR0_PE, %eax |
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movl %eax, %cr0 |
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/* Now really going into real mode */ |
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ljmp $0, $RELOCATED(1f) |
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1: |
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movw $0x0, %ax |
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movw %ax, %ds |
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movw %ax, %es |
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movw %ax, %ss |
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movw %ax, %fs |
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movw %ax, %gs |
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/* |
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* This is a FAR JMP to the OS waking vector. |
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* The C code changes the address to be correct. |
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*/ |
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.byte 0xea
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__wakeup_offset = RELOCATED(.) |
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.word 0x0000
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__wakeup_segment = RELOCATED(.) |
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.word 0x0000
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.globl __wakeup_size
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__wakeup_size: |
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.long . - __wakeup |
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