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/*

 * Copyright (C) 2001-2004 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.

 */

#include <arch/pm.h>

#include <arch/mm/page.h>

#include <arch/types.h>

#include <arch/interrupt.h>

#include <arch/asm.h>

#include <interrupt.h>

#include <mm/as.h>

#include <config.h>

#include <memstr.h>

#include <mm/slab.h>

#include <debug.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 */

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

};

idescriptor_t idt[IDT_ITEMS];

ptr_16_64_t gdtr = {.limit = sizeof(gdt), .base= (__u64) gdt };

ptr_16_64_t idtr = {.limit = sizeof(idt), .base= (__u64) idt };

static tss_t tss;

tss_t *tss_p = NULL;

void gdt_tss_setbase(descriptor_t *d, __address 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, __u32 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, __address 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((__address) 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, ((__address) interrupt_handlers) + i*interrupt_handler_size);

		exc_register(i, "undef", (iroutine)null_interrupt);

	}

	exc_register( 7, "nm_fault", nm_fault);

	exc_register(12, "ss_fault", ss_fault);

	exc_register(13, "gp_fault", gp_fault);

	exc_register(14, "ident_mapper", ident_page_fault);

}

/** 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((__address) AS_KERNEL->page_table);

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

		if (!tss_p)

			panic("could not allocate TSS\n");

	}

	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], (__address) 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));

}