contiki/cpu/x86/mm/tss.c

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/*
* Copyright (C) 2015-2016, Intel Corporation. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. 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.
*
* 3. Neither the name of the copyright holder nor the names of its
* contributors may be used to endorse or promote products derived
* from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* ``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
* COPYRIGHT HOLDER OR CONTRIBUTORS 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 "gdt.h"
#include "gdt-layout.h"
#include "prot-domains.h"
#include "segmentation.h"
#include "stacks.h"
#include "tss.h"
/* System-wide TSS */
tss_t ATTR_BSS_KERN sys_tss;
static segment_desc_t ATTR_BSS_GDT sys_tss_desc;
/*---------------------------------------------------------------------------*/
/**
* \brief Initialize system-wide TSS.
*/
void
tss_init(void)
{
segment_desc_t seg_desc;
/* Initialize TSS */
KERN_WRITEW(sys_tss.iomap_base, sizeof(sys_tss));
KERN_WRITEL(sys_tss.esp2, ((uint32_t)stacks_int) + STACKS_SIZE_INT);
KERN_WRITEL(sys_tss.ss2, GDT_SEL_STK_INT);
KERN_WRITEL(sys_tss.esp0, ((uint32_t)stacks_exc) + STACKS_SIZE_EXC);
KERN_WRITEL(sys_tss.ss0, GDT_SEL_STK_EXC);
segment_desc_init(&seg_desc,
KERN_DATA_OFF_TO_PHYS_ADDR(&sys_tss), sizeof(sys_tss),
SEG_FLAG(DPL, PRIV_LVL_EXC) |
SEG_DESCTYPE_SYS | SEG_TYPE_TSS32_AVAIL);
gdt_insert(GDT_IDX_OF_DESC(&sys_tss_desc), seg_desc);
__asm__ __volatile__ (
"ltr %0"
:
: "r" ((uint16_t)GDT_SEL_OF_DESC(&sys_tss_desc, 0)));
}
/*---------------------------------------------------------------------------*/