osd-contiki/cpu/x86/mm/gdt-layout.h
Michael LeMay e0aefd11d9 x86: Add support for SW-switched segment-based protection domains
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.
2016-04-22 08:16:43 -07:00

139 lines
5.1 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.
*/
#ifndef CPU_X86_MM_GDT_LAYOUT_H_
#define CPU_X86_MM_GDT_LAYOUT_H_
#include "prot-domains.h"
#if X86_CONF_PROT_DOMAINS == X86_CONF_PROT_DOMAINS__PAGING
/**
* Number of fixed GDT descriptors. Additional descriptors may be defined
* outside of gdt.c.
*/
#define GDT_NUM_FIXED_DESC 7
#elif X86_CONF_PROT_DOMAINS_MULTI_SEG
#define GDT_NUM_FIXED_DESC 11
#else
#define GDT_NUM_FIXED_DESC 3
#endif
#define GDT_IDX_NULL 0
/**
* Flat code segment, used at boot and also for the rest of the system's
* runtime when protection domains are disabled
*/
#define GDT_IDX_CODE_FLAT 1
/**
* Flat data segment, used at boot and also for the rest of the system's
* runtime when protection domains are disabled
*/
#define GDT_IDX_DATA_FLAT 2
#if X86_CONF_PROT_DOMAINS != X86_CONF_PROT_DOMAINS__NONE
/** Default (post-boot) code segment */
#define GDT_IDX_CODE 3
/**
* Same bounds and permissions as default code segment, but at the interrupt
* handler privilege level
*/
#define GDT_IDX_CODE_INT 4
/** Stack segment for interrupt handlers */
#define GDT_IDX_STK_INT 5
#if X86_CONF_PROT_DOMAINS == X86_CONF_PROT_DOMAINS__PAGING
#define GDT_IDX_CODE_EXC GDT_IDX_CODE_FLAT
/** Default data segment used by code at all privilege levels */
#define GDT_IDX_DATA 6
#define GDT_IDX_STK GDT_IDX_DATA
#define GDT_IDX_STK_EXC GDT_IDX_DATA_FLAT
#else
/**
* Same bounds and permissions as default code segment, but at the exception
* handler privilege level
*/
#define GDT_IDX_CODE_EXC 6
/** R/W kernel data descriptor used during boot stage 1 */
#define GDT_IDX_DATA_KERN_EXC 7
/** Default data segment used by code at all privilege levels */
#define GDT_IDX_DATA 8
/**
* Default stack segment, which overlaps with the beginning of the default data
* segment
*/
#define GDT_IDX_STK 9
/** Stack segment for exception handlers */
#define GDT_IDX_STK_EXC 10
#if X86_CONF_PROT_DOMAINS == X86_CONF_PROT_DOMAINS__TSS
#define GDT_IDX_TSS(dom_id) (GDT_NUM_FIXED_DESC + (2 * (dom_id)))
#define GDT_IDX_LDT(dom_id) (GDT_NUM_FIXED_DESC + (2 * (dom_id)) + 1)
#else
#define GDT_IDX_LDT(dom_id) (GDT_NUM_FIXED_DESC + (dom_id))
#endif
#endif
#else
#define GDT_IDX_CODE GDT_IDX_CODE_FLAT
#define GDT_IDX_CODE_INT GDT_IDX_CODE_FLAT
#define GDT_IDX_CODE_EXC GDT_IDX_CODE_FLAT
#define GDT_IDX_DATA GDT_IDX_DATA_FLAT
#define GDT_IDX_STK GDT_IDX_DATA_FLAT
#define GDT_IDX_STK_INT GDT_IDX_DATA_FLAT
#define GDT_IDX_STK_EXC GDT_IDX_DATA_FLAT
#endif
#define GDT_SEL(idx, rpl) (((idx) << 3) | (rpl))
#define DT_SEL_GET_IDX(sel) ((sel) >> 3)
#define DT_SEL_GET_RPL(sel) ((sel) & 3)
#define GDT_SEL_NULL GDT_SEL(GDT_IDX_NULL, 0)
#define GDT_SEL_CODE_FLAT GDT_SEL(GDT_IDX_CODE_FLAT, PRIV_LVL_EXC)
#define GDT_SEL_DATA_FLAT GDT_SEL(GDT_IDX_DATA_FLAT, PRIV_LVL_EXC)
#define GDT_SEL_CODE GDT_SEL(GDT_IDX_CODE, PRIV_LVL_USER)
#define GDT_SEL_CODE_INT GDT_SEL(GDT_IDX_CODE_INT, PRIV_LVL_INT)
#define GDT_SEL_CODE_EXC GDT_SEL(GDT_IDX_CODE_EXC, PRIV_LVL_EXC)
#define GDT_SEL_DATA GDT_SEL(GDT_IDX_DATA, PRIV_LVL_EXC)
#define GDT_SEL_DATA_KERN_EXC GDT_SEL(GDT_IDX_DATA_KERN_EXC, PRIV_LVL_EXC)
#define GDT_SEL_STK GDT_SEL(GDT_IDX_STK, PRIV_LVL_USER)
#define GDT_SEL_STK_INT GDT_SEL(GDT_IDX_STK_INT, PRIV_LVL_INT)
#define GDT_SEL_STK_EXC GDT_SEL(GDT_IDX_STK_EXC, PRIV_LVL_EXC)
#define GDT_SEL_TSS(dom_id) GDT_SEL(GDT_IDX_TSS(dom_id), PRIV_LVL_USER)
#define GDT_SEL_LDT(dom_id) GDT_SEL(GDT_IDX_LDT(dom_id), PRIV_LVL_USER)
#endif /* CPU_X86_MM_GDT_LAYOUT_H_ */