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178 palkovsky 1
/*
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 * Copyright (C) 2001-2004 Jakub Jermar
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 * 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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 *
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 * - 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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 * - 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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 * - The name of the author may not be used to endorse or promote products
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 *   derived from this software without specific prior written permission.
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 *
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 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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 */
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#include <arch/pm.h>
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#include <arch/mm/page.h>
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#include <arch/types.h>
206 palkovsky 32
#include <arch/interrupt.h>
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#include <arch/asm.h>
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206 palkovsky 35
#include <config.h>
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206 palkovsky 37
#include <memstr.h>
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#include <mm/heap.h>
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#include <debug.h>
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178 palkovsky 41
/*
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 * There is no segmentation in long mode so we set up flat mode. In this
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 * mode, we use, for each privilege level, two segments spanning the
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 * whole memory. One is for code and one is for data.
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 */
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struct descriptor gdt[GDT_ITEMS] = {
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    /* NULL descriptor */
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    { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 },
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    /* KTEXT descriptor */
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    { .limit_0_15  = 0xffff,
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      .base_0_15   = 0,
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      .base_16_23  = 0,
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      .access      = AR_PRESENT | AR_CODE | DPL_KERNEL | AR_READABLE ,
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      .limit_16_19 = 0xf,
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      .available   = 0,
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      .longmode    = 1,
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      .special     = 0,
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      .granularity = 1,
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      .base_24_31  = 0 },
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    /* KDATA descriptor */
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    { .limit_0_15  = 0xffff,
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      .base_0_15   = 0,
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      .base_16_23  = 0,
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      .access      = AR_PRESENT | AR_DATA | AR_WRITABLE | DPL_KERNEL,
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      .limit_16_19 = 0xf,
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      .available   = 0,
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      .longmode    = 0,
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      .special     = 0,
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      .granularity = 1,
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      .base_24_31  = 0 },
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    /* UTEXT descriptor */
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    { .limit_0_15  = 0xffff,
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      .base_0_15   = 0,
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      .base_16_23  = 0,
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      .access      = AR_PRESENT | AR_CODE | DPL_USER,
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      .limit_16_19 = 0xf,
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      .available   = 0,
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      .longmode    = 1,
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      .special     = 0,
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      .granularity = 1,
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      .base_24_31  = 0 },
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    /* UDATA descriptor */
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    { .limit_0_15  = 0xffff,
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      .base_0_15   = 0,
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      .base_16_23  = 0,
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      .access      = AR_PRESENT | AR_DATA | AR_WRITABLE | DPL_USER,
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      .limit_16_19 = 0xf,
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      .available   = 0,
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      .longmode    = 0,
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      .special     = 1,
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      .granularity = 1,
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      .base_24_31  = 0 },
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    /* KTEXT 32-bit protected, for protected mode before long mode */
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    { .limit_0_15  = 0xffff,
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      .base_0_15   = 0,
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      .base_16_23  = 0,
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      .access      = AR_PRESENT | AR_CODE | DPL_KERNEL | AR_READABLE,
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      .limit_16_19 = 0xf,
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      .available   = 0,
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      .longmode    = 0,
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      .special     = 1,
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      .granularity = 1,
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      .base_24_31  = 0 },
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    /* TSS descriptor - set up will be completed later,
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     * on AMD64 it is 64-bit - 2 items in table */
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    { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 },
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    { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 }
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};
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struct idescriptor idt[IDT_ITEMS];
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struct ptr_16_64 gdtr = {.limit = sizeof(gdt), .base= (__u64) gdt };
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struct ptr_16_64 idtr = {.limit = sizeof(idt), .base= (__u64) idt };
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178 palkovsky 116
static struct tss tss;
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struct tss *tss_p = NULL;
178 palkovsky 118
 
206 palkovsky 119
void gdt_tss_setbase(struct descriptor *d, __address base)
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{
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    struct tss_descriptor *td = (struct tss_descriptor *) d;
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    td->base_0_15 = base & 0xffff;
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    td->base_16_23 = ((base) >> 16) & 0xff;
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    td->base_24_31 = ((base) >> 24) & 0xff;
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    td->base_32_63 = ((base) >> 32);
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}
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void gdt_tss_setlimit(struct descriptor *d, __u32 limit)
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{
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    struct tss_descriptor *td = (struct tss_descriptor *) d;
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    td->limit_0_15 = limit & 0xffff;
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    td->limit_16_19 = (limit >> 16) & 0xf;
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}
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void idt_setoffset(struct idescriptor *d, __address offset)
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{
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    /*
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     * Offset is a linear address.
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     */
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    d->offset_0_15 = offset & 0xffff;
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    d->offset_16_31 = offset >> 16 & 0xffff;
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    d->offset_32_63 = offset >> 32;
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}
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void tss_initialize(struct tss *t)
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{
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    memsetb((__address) t, sizeof(struct tss), 0);
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}
151
 
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/*
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 * This function takes care of proper setup of IDT and IDTR.
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 */
155
void idt_init(void)
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{
157
    struct idescriptor *d;
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    int i;
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160
    for (i = 0; i < IDT_ITEMS; i++) {
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        d = &idt[i];
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        d->unused = 0;
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        d->selector = gdtselector(KTEXT_DES);
206 palkovsky 165
 
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        d->present = 1;
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        d->type = AR_INTERRUPT; /* masking interrupt */
168
 
169
        if (i == VECTOR_SYSCALL) {
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            /*
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             * The syscall interrupt gate must be calleable from userland.
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             */
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            d->dpl |= PL_USER;
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        }
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        idt_setoffset(d, ((__address) interrupt_handlers) + i*interrupt_handler_size);
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        trap_register(i, null_interrupt);
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    }
179
    trap_register(13, gp_fault);
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    trap_register( 7, nm_fault);
224 palkovsky 181
    trap_register(12, ss_fault);   
206 palkovsky 182
}
183
 
184
 
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/* Clean IOPL(12,13) and NT(14) flags in EFLAGS register */
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static void clean_IOPL_NT_flags(void)
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{
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    asm
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    (
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        "pushfq;"
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        "pop %%rax;"
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        "and $~(0x7000),%%rax;"
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        "pushq %%rax;"
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        "popfq;"
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        :
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        :
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        :"%rax"
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    );
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}
200
 
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/* Clean AM(18) flag in CR0 register */
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static void clean_AM_flag(void)
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{
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    asm
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    (
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        "mov %%cr0,%%rax;"
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        "and $~(0x40000),%%rax;"
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        "mov %%rax,%%cr0;"
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        :
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        :
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        :"%rax"
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    );
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}
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void pm_init(void)
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{
229 palkovsky 217
    struct descriptor *gdt_p = (struct descriptor *) gdtr.base;
208 palkovsky 218
    struct tss_descriptor *tss_desc;
206 palkovsky 219
 
220
    /*
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     * Each CPU has its private GDT and TSS.
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     * All CPUs share one IDT.
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     */
224
 
225
    if (config.cpu_active == 1) {
226
        idt_init();
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        /*
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         * NOTE: bootstrap CPU has statically allocated TSS, because
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         * the heap hasn't been initialized so far.
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         */
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        tss_p = &tss;
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    }
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    else {
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        tss_p = (struct tss *) malloc(sizeof(struct tss));
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        if (!tss_p)
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            panic("could not allocate TSS\n");
237
    }
238
 
239
    tss_initialize(tss_p);
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208 palkovsky 241
    tss_desc = (struct tss_descriptor *) (&gdt_p[TSS_DES]);
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    tss_desc->present = 1;
243
    tss_desc->type = AR_TSS;
244
    tss_desc->dpl = PL_KERNEL;
206 palkovsky 245
 
246
    gdt_tss_setbase(&gdt_p[TSS_DES], (__address) tss_p);
247
    gdt_tss_setlimit(&gdt_p[TSS_DES], sizeof(struct tss) - 1);
248
 
229 palkovsky 249
    __asm__("lgdt %0" : : "m"(gdtr));
250
    __asm__("lidt %0" : : "m"(idtr));
206 palkovsky 251
    /*
252
     * As of this moment, the current CPU has its own GDT pointing
253
     * to its own TSS. We just need to load the TR register.
254
     */
255
    __asm__("ltr %0" : : "r" ((__u16) gdtselector(TSS_DES)));
256
 
257
    clean_IOPL_NT_flags();    /* Disable I/O on nonprivileged levels */
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    clean_AM_flag();          /* Disable alignment check */
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}