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The x86/init/common/ folder holds all cpu initialization code - idt and gdt setup, interrupts and cpu initialization. On this folder will also sit any SoC specific implementation of the functions called from cpu_init().
94 lines
3.4 KiB
C
94 lines
3.4 KiB
C
/*
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* Copyright (C) 2015, Intel Corporation. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* 3. Neither the name of the copyright holder nor the names of its
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* contributors may be used to endorse or promote products derived
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* from this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
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* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
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* COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
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* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
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* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
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* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
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* OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#include <stdint.h>
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#include "helpers.h"
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#define NUM_DESC 256
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typedef struct idtr {
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uint16_t limit;
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uint32_t base;
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} __attribute__((packed)) idtr_t;
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typedef struct intr_gate_desc {
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uint16_t offset_low;
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uint16_t selector; /* Segment Selector for destination code segment */
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uint16_t fixed:11;
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uint16_t d:1; /* Size of gate: 1 = 32 bits; 0 = 16 bits */
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uint16_t pad:1;
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uint16_t dpl:2; /* Descriptor Privilege Level */
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uint16_t p:1; /* Segment Present flag */
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uint16_t offset_high;
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} __attribute__((packed)) intr_gate_desc_t;
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/* According to Intel Combined Manual, Vol. 3, Section 6.10, the base addresses
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* of the IDT should be aligned on an 8-byte boundary to maximize performance
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* of cache line fills.
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*/
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static intr_gate_desc_t idt[NUM_DESC] __attribute__ ((aligned(8)));
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/* XXX: If you change this function prototype, make sure you fix the assembly
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* code in SET_INTERRUPT_HANDLER macro in interrupt.h. Otherwise, you might
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* face a very-hard-to-find bug in the interrupt handling system.
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*/
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void
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idt_set_intr_gate_desc(int intr_num, uint32_t offset)
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{
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intr_gate_desc_t *desc = &idt[intr_num];
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desc->offset_low = offset & 0xFFFF;
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desc->selector = 0x08; /* Offset in GDT for code segment */
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desc->fixed = BIT(9) | BIT(10);
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desc->d = 1;
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desc->dpl = 0;
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desc->p = 1;
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desc->offset_high = (offset >> 16) & 0xFFFF;
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}
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/*---------------------------------------------------------------------------*/
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/* Initialize Interrupt Descriptor Table. The IDT is initialized with
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* null descriptors. Therefore, any interrupt at this point will cause
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* a triple fault.
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*/
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void
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idt_init(void)
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{
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idtr_t idtr;
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/* Initialize idtr structure */
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idtr.limit = (sizeof(intr_gate_desc_t) * NUM_DESC) - 1;
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idtr.base = (uint32_t)&idt;
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/* Load IDTR register */
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__asm__("lidt %0\n\t" :: "m" (idtr));
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}
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