x86/gdt.h

/*
 * Copyright (c) 2008-2014, Pedigree Developers
 *
 * Please see the CONTRIB file in the root of the source tree for a full
 * list of contributors.
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */

#ifndef KERNEL_PROCESSOR_X86_GDT_H
#define KERNEL_PROCESSOR_X86_GDT_H

#include "pedigree/kernel/compiler.h"
#include "pedigree/kernel/processor/types.h"

class X86GdtManager
{
  public:
    inline static X86GdtManager &instance()
    {
        return m_Instance;
    }

    void initialise(size_t processorCount) INITIALISATION_ONLY;
    static void initialiseProcessor() INITIALISATION_ONLY;

    void setTlsBase(uintptr_t base);

  private:
    X86GdtManager() INITIALISATION_ONLY;
    X86GdtManager(const X86GdtManager &);
    X86GdtManager &operator=(const X86GdtManager &);
    ~X86GdtManager();

    void setSegmentDescriptor(
        size_t index, uint32_t base, uint32_t limit, uint8_t flags,
        uint8_t flags2);
    void setTssDescriptor(size_t index, uint32_t base) INITIALISATION_ONLY;

    void initialiseTss(struct X86TaskStateSegment *pTss) INITIALISATION_ONLY;
    void
    initialiseDoubleFaultTss(X86TaskStateSegment *pTss) INITIALISATION_ONLY;

    struct segment_descriptor
    {
        uint16_t limit0;
        uint16_t base0;
        uint8_t base1;
        uint8_t flags;
        uint8_t flags_limit1;
        uint8_t base2;
    } PACKED;

    segment_descriptor *m_Gdt;
    size_t m_DescriptorCount;

    static X86GdtManager m_Instance;
};

#endif