mirror of
https://github.com/oliverschmidt/contiki.git
synced 2024-11-19 18:40:17 +00:00
e0aefd11d9
This patch extends the protection domain framework with a third plugin that is a hybrid of the previous two. The hardware task switching mechanism has a strictly-defined format for TSS data structures that causes more space to be consumed than would otherwise be required. This patch defines a smaller data structure that is allocated for each protection domain, only requiring 32 bytes instead of 128 bytes. It uses the same multi-segment memory layout as the TSS-based plugin and leaves paging disabled. However, it uses a similar mechanism as the paging plugin to perform system call dispatches and returns. For additional information, please refer to cpu/x86/mm/README.md.
71 lines
2.7 KiB
C
71 lines
2.7 KiB
C
/*
|
|
* 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)));
|
|
}
|
|
/*---------------------------------------------------------------------------*/
|