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/*

 * Copyright (c) 2006 Martin Decky

 * 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 ia32xen

 * @{

 */

/** @file

 */

#include <arch/pm.h>

#include <config.h>

#include <arch/types.h>

#include <arch/interrupt.h>

#include <arch/asm.h>

#include <arch/context.h>

#include <panic.h>

#include <arch/mm/page.h>

#include <mm/slab.h>

#include <memstr.h>

#include <interrupt.h>

/*

 * Early ia32xen configuration functions and data structures.

 */

/*

 * We have no use for segmentation 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.

 *

 * One is for GS register which holds pointer to the TLS thread

 * structure in it's base.

 */

descriptor_t gdt[GDT_ITEMS] = {

    /* NULL descriptor */

    { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 },

    /* KTEXT descriptor */

    { 0xffff, 0, 0, AR_PRESENT | AR_CODE | DPL_KERNEL, 0xf, 0, 0, 1, 1, 0 },

    /* KDATA descriptor */

    { 0xffff, 0, 0, AR_PRESENT | AR_DATA | AR_WRITABLE | DPL_KERNEL, 0xf, 0, 0, 1, 1, 0 },

    /* UTEXT descriptor */

    { 0xffff, 0, 0, AR_PRESENT | AR_CODE | DPL_USER, 0xf, 0, 0, 1, 1, 0 },

    /* UDATA descriptor */

    { 0xffff, 0, 0, AR_PRESENT | AR_DATA | AR_WRITABLE | DPL_USER, 0xf, 0, 0, 1, 1, 0 },

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

    { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 },

    /* TLS descriptor */

    { 0xffff, 0, 0, AR_PRESENT | AR_DATA | AR_WRITABLE | DPL_USER, 0xf, 0, 0, 1, 1, 0 },

};

static trap_info_t traps[IDT_ITEMS + 1];

static tss_t tss;

tss_t *tss_p = NULL;

/* gdtr is changed by kmp before next CPU is initialized */

ptr_16_32_t bootstrap_gdtr = { .limit = sizeof(gdt), .base = KA2PA((uintptr_t) gdt) };

ptr_16_32_t gdtr = { .limit = sizeof(gdt), .base = (uintptr_t) gdt };

void gdt_setbase(descriptor_t *d, uintptr_t base)

{

    d->base_0_15 = base & 0xffff;

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

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

}

void gdt_setlimit(descriptor_t *d, uint32_t limit)

{

    d->limit_0_15 = limit & 0xffff;

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

}

void tss_initialize(tss_t *t)

{

    memsetb(t, sizeof(struct tss), 0);

}

static void trap(void)

{

}

void traps_init(void)

{

    index_t i;

    for (i = 0; i < IDT_ITEMS; i++) {

        traps[i].vector = i;

        if (i == VECTOR_SYSCALL)

            traps[i].flags = 3;

        else

            traps[i].flags = 0;

        traps[i].cs = XEN_CS;

        traps[i].address = trap;

    }

    traps[IDT_ITEMS].vector = 0;

    traps[IDT_ITEMS].flags = 0;

    traps[IDT_ITEMS].cs = 0;

    traps[IDT_ITEMS].address = NULL;

}

/* Clean IOPL(12,13) and NT(14) flags in EFLAGS register */

static void clean_IOPL_NT_flags(void)

{

//  asm volatile (

//      "pushfl\n"

//      "pop %%eax\n"

//      "and $0xffff8fff, %%eax\n"

//      "push %%eax\n"

//      "popfl\n"

//      : : : "eax"

//  );

}

/* Clean AM(18) flag in CR0 register */

static void clean_AM_flag(void)

{

//  asm volatile (

//      "mov %%cr0, %%eax\n"

//      "and $0xfffbffff, %%eax\n"

//      "mov %%eax, %%cr0\n"

//      : : : "eax"

//  );

}

void pm_init(void)

{

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

//  gdtr_load(&gdtr);

    if (config.cpu_active == 1) {

        traps_init();

        xen_set_trap_table(traps);

        /*

         * NOTE: bootstrap CPU has statically allocated TSS, because

         * the heap hasn't been initialized so far.

         */

        tss_p = &tss;

    } else {

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

        if (!tss_p)

            panic("Cannot allocate TSS.");

    }

//  tss_initialize(tss_p);

    gdt_p[TSS_DES].access = AR_PRESENT | AR_TSS | DPL_KERNEL;

    gdt_p[TSS_DES].special = 1;

    gdt_p[TSS_DES].granularity = 0;

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

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

    /*

     * 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(selector(TSS_DES));

    clean_IOPL_NT_flags();    /* Disable I/O on nonprivileged levels and clear NT flag. */

    clean_AM_flag();          /* Disable alignment check */

}

void set_tls_desc(uintptr_t tls)

{

    ptr_16_32_t cpugdtr;

    descriptor_t *gdt_p;

    gdtr_store(&cpugdtr);

    gdt_p = (descriptor_t *) cpugdtr.base;

    gdt_setbase(&gdt_p[TLS_DES], tls);

    /* Reload gdt register to update GS in CPU */

    gdtr_load(&cpugdtr);

}

/** @}

 */