osd-contiki/cpu/x86/init/common/gdt.h

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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.
*/
#ifndef GDT_H
#define GDT_H
#include "gdt-layout.h"
#include "prot-domains.h"
#include "segmentation.h"
extern segment_desc_t ATTR_KERN_ADDR_SPACE gdt[];
extern int ATTR_KERN_ADDR_SPACE _ebss_gdt_addr;
#define GDT_IDX_OF_DESC(ptr) \
((((uintptr_t)(ptr)) - ((uintptr_t)&gdt))/ \
sizeof(segment_desc_t))
typedef struct far_pointer {
/** Far pointer offset. */
uint32_t offset;
/** Far pointer segment/gate selector. */
uint16_t sel;
uint16_t pad;
} __attribute__((packed)) far_pointer_t;
/**
* \brief Compute the selector for a GDT entry allocated somewhere besides gdt.c.
* \param ptr Pointer to GDT descriptor.
* \param rpl Requested Privilege Level.
*/
#define GDT_SEL_OF_DESC(ptr, rpl) GDT_SEL(GDT_IDX_OF_DESC(ptr), rpl)
/* Section for fixed GDT entries */
#define ATTR_BSS_GDT \
__attribute__((section(".gdt_bss"))) ATTR_KERN_ADDR_SPACE
/* Section for TSS and LDT descriptors for protection domains */
#define ATTR_BSS_GDT_MID \
__attribute__((used, section(".gdt_bss_mid"))) ATTR_KERN_ADDR_SPACE
/* Section for other GDT entries */
#define ATTR_BSS_GDT_START \
__attribute__((section(".gdt_bss_start"))) ATTR_KERN_ADDR_SPACE
void gdt_copy_desc_change_dpl(unsigned int dest_idx,
unsigned int src_idx,
unsigned dpl);
void gdt_init(void) ATTR_CODE_BOOT;
void gdt_insert(unsigned int idx, segment_desc_t desc);
void gdt_insert_boot(unsigned int idx, segment_desc_t desc) ATTR_CODE_BOOT;
void gdt_lookup(unsigned int idx, segment_desc_t *desc);
#endif /* GDT_H */