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/*

 * Copyright (c) 2008 Jakub Jermar

 * Copyright (c) 2005-2006 Ondrej Palkovsky

 * All rights reserved.

 *

 * Redistribution and use in source and binary forms, with or without

 * modification, are permitted provided that the following conditions

 * are met:

 *

 * - Redistributions of source code must retain the above copyright

 *   notice, this list of conditions and the following disclaimer.

 * - Redistributions in binary form must reproduce the above copyright

 *   notice, this list of conditions and the following disclaimer in the

 *   documentation and/or other materials provided with the distribution.

 * - The name of the author may not be used to endorse or promote products

 *   derived from this software without specific prior written permission.

 *

 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR

 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES

 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.

 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,

 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT

 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,

 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY

 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT

 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF

 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

 */

/** @addtogroup amd64  

 * @{

 */

/** @file

 */

#include <arch.h>

#include <arch/pm.h>

#include <arch/asm.h>

#include <mm/as.h>

#include <mm/frame.h>

#include <memstr.h>

#include <mm/slab.h>

/*

 * There is no segmentation in long mode so we set up flat mode. In this

 * mode, we use, for each privilege level, two segments spanning the

 * whole memory. One is for code and one is for data.

 */

descriptor_t gdt[GDT_ITEMS] = {

    /* NULL descriptor */

    { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 },

    /* KTEXT descriptor */

    { .limit_0_15  = 0xffff,

      .base_0_15   = 0,

      .base_16_23  = 0,

      .access      = AR_PRESENT | AR_CODE | DPL_KERNEL | AR_READABLE,

      .limit_16_19 = 0xf,

      .available   = 0,

      .longmode    = 1,

      .special     = 0,

      .granularity = 1,

      .base_24_31  = 0 },

    /* KDATA descriptor */

    { .limit_0_15  = 0xffff,

      .base_0_15   = 0,

      .base_16_23  = 0,

      .access      = AR_PRESENT | AR_DATA | AR_WRITABLE | DPL_KERNEL,

      .limit_16_19 = 0xf,

      .available   = 0,

      .longmode    = 0,

      .special     = 0,

      .granularity = 1,

      .base_24_31  = 0 },

    /* UDATA descriptor */

    { .limit_0_15  = 0xffff,

      .base_0_15   = 0,

      .base_16_23  = 0,

      .access      = AR_PRESENT | AR_DATA | AR_WRITABLE | DPL_USER,

      .limit_16_19 = 0xf,

      .available   = 0,

      .longmode    = 0,

      .special     = 1,

      .granularity = 1,

      .base_24_31  = 0 },

    /* UTEXT descriptor */

    { .limit_0_15  = 0xffff,

      .base_0_15   = 0,

      .base_16_23  = 0,

      .access      = AR_PRESENT | AR_CODE | DPL_USER,

      .limit_16_19 = 0xf,

      .available   = 0,

      .longmode    = 1,

      .special     = 0,

      .granularity = 1,

      .base_24_31  = 0 },

    /* KTEXT 32-bit protected, for protected mode before long mode */

    { .limit_0_15  = 0xffff,

      .base_0_15   = 0,

      .base_16_23  = 0,

      .access      = AR_PRESENT | AR_CODE | DPL_KERNEL | AR_READABLE,

      .limit_16_19 = 0xf,

      .available   = 0,

      .longmode    = 0,

      .special     = 1,

      .granularity = 1,

      .base_24_31  = 0 },

    /* TSS descriptor - set up will be completed later,

     * on AMD64 it is 64-bit - 2 items in table */

    { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 },

    { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 },

    /* VESA Init descriptor */

#ifdef CONFIG_FB    

    { 0xffff, 0, VESA_INIT_SEGMENT >> 12, AR_PRESENT | AR_CODE | DPL_KERNEL,

      0xf, 0, 0, 0, 0, 0

    }

#endif

};

idescriptor_t idt[IDT_ITEMS];

ptr_16_64_t gdtr = {.limit = sizeof(gdt), .base = (uint64_t) gdt };

ptr_16_64_t idtr = {.limit = sizeof(idt), .base = (uint64_t) idt };

static tss_t tss;

tss_t *tss_p = NULL;

void gdt_tss_setbase(descriptor_t *d, uintptr_t base)

{

    tss_descriptor_t *td = (tss_descriptor_t *) d;

    td->base_0_15 = base & 0xffff;

    td->base_16_23 = ((base) >> 16) & 0xff;

    td->base_24_31 = ((base) >> 24) & 0xff;

    td->base_32_63 = ((base) >> 32);

}

void gdt_tss_setlimit(descriptor_t *d, uint32_t limit)

{

    struct tss_descriptor *td = (tss_descriptor_t *) d;

    td->limit_0_15 = limit & 0xffff;

    td->limit_16_19 = (limit >> 16) & 0xf;

}

void idt_setoffset(idescriptor_t *d, uintptr_t offset)

{

    /*

     * Offset is a linear address.

     */

    d->offset_0_15 = offset & 0xffff;

    d->offset_16_31 = offset >> 16 & 0xffff;

    d->offset_32_63 = offset >> 32;

}

void tss_initialize(tss_t *t)

{

    memsetb(t, sizeof(tss_t), 0);

}

/*

 * This function takes care of proper setup of IDT and IDTR.

 */

void idt_init(void)

{

    idescriptor_t *d;

    int i;

    for (i = 0; i < IDT_ITEMS; i++) {

        d = &idt[i];

        d->unused = 0;

        d->selector = gdtselector(KTEXT_DES);

        d->present = 1;

        d->type = AR_INTERRUPT; /* masking interrupt */

        idt_setoffset(d, ((uintptr_t) interrupt_handlers) +

            i * interrupt_handler_size);

    }

}

/** Initialize segmentation - code/data/idt tables

 *

 */

void pm_init(void)

{

    descriptor_t *gdt_p = (struct descriptor *) gdtr.base;

    tss_descriptor_t *tss_desc;

    /*

     * Each CPU has its private GDT and TSS.

     * All CPUs share one IDT.

     */

    if (config.cpu_active == 1) {

        idt_init();

        /*

         * NOTE: bootstrap CPU has statically allocated TSS, because

         * the heap hasn't been initialized so far.

         */

        tss_p = &tss;

    }

    else {

        /* We are going to use malloc, which may return

         * non boot-mapped pointer, initialize the CR3 register

         * ahead of page_init */

        write_cr3((uintptr_t) AS_KERNEL->genarch.page_table);

        tss_p = (struct tss *) malloc(sizeof(tss_t), FRAME_ATOMIC);

        if (!tss_p)

            panic("Cannot allocate TSS.");

    }

    tss_initialize(tss_p);

    tss_desc = (tss_descriptor_t *) (&gdt_p[TSS_DES]);

    tss_desc->present = 1;

    tss_desc->type = AR_TSS;

    tss_desc->dpl = PL_KERNEL;

    gdt_tss_setbase(&gdt_p[TSS_DES], (uintptr_t) tss_p);

    gdt_tss_setlimit(&gdt_p[TSS_DES], TSS_BASIC_SIZE - 1);

    gdtr_load(&gdtr);

    idtr_load(&idtr);

    /*

     * As of this moment, the current CPU has its own GDT pointing

     * to its own TSS. We just need to load the TR register.

     */

    tr_load(gdtselector(TSS_DES));

}

/* Reboot the machine by initiating

 * a triple fault

 */

void arch_reboot(void)

{

    preemption_disable();

    ipl_t ipl = interrupts_disable();

    memsetb(idt, sizeof(idt), 0);

    idtr_load(&idtr);

    interrupts_restore(ipl);

    asm volatile (

        "int $0x03\n"

        "cli\n"

        "hlt\n"

    );

}

/** @}

 */