/******************************************************************************

 * arch/x86/pv/emulate.c

 *

 * Common PV emulation code

 *

 * Modifications to Linux original are copyright (c) 2002-2004, K A Fraser

 *

 * This program is free software; you can redistribute it and/or modify

 * it under the terms of the GNU General Public License as published by

 * the Free Software Foundation; either version 2 of the License, or

 * (at your option) any later version.

 *

 * This program is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

 * GNU General Public License for more details.

 *

 * You should have received a copy of the GNU General Public License

 * along with this program; If not, see <http://www.gnu.org/licenses/>.

 */

#include <xen/guest_access.h>

#include <asm/debugreg.h>

#include "emulate.h"

int pv_emul_read_descriptor(unsigned int sel, const struct vcpu *v,

                            unsigned long *base, unsigned long *limit,

                            unsigned int *ar, bool insn_fetch)

{

    struct desc_struct desc;

    if ( sel < 4)

        desc.b = desc.a = 0;

    else if ( __get_user(desc,

                         (const struct desc_struct *)(!(sel & 4)

                                                      ? GDT_VIRT_START(v)

                                                      : LDT_VIRT_START(v))

                         + (sel >> 3)) )

        return 0;

    if ( !insn_fetch )

        desc.b &= ~_SEGMENT_L;

    *ar = desc.b & 0x00f0ff00;

    if ( !(desc.b & _SEGMENT_L) )

    {

        *base = ((desc.a >> 16) + ((desc.b & 0xff) << 16) +

                 (desc.b & 0xff000000));

        *limit = (desc.a & 0xffff) | (desc.b & 0x000f0000);

        if ( desc.b & _SEGMENT_G )

            *limit = ((*limit + 1) << 12) - 1;

#ifndef NDEBUG

        if ( sel > 3 )

        {

            unsigned int a, l;

            unsigned char valid;

            asm volatile (

                "larl %2,%0 ; setz %1"

                : "=r" (a), "=qm" (valid) : "rm" (sel));

            BUG_ON(valid && ((a & 0x00f0ff00) != *ar));

            asm volatile (

                "lsll %2,%0 ; setz %1"

                : "=r" (l), "=qm" (valid) : "rm" (sel));

            BUG_ON(valid && (l != *limit));

        }

#endif

    }

    else

    {

        *base = 0UL;

        *limit = ~0UL;

    }

    return 1;

}

void pv_emul_instruction_done(struct cpu_user_regs *regs, unsigned long rip)

{

    regs->rip = rip;

    regs->eflags &= ~X86_EFLAGS_RF;

    if ( regs->eflags & X86_EFLAGS_TF )

    {

        current->arch.debugreg[6] |= DR_STEP | DR_STATUS_RESERVED_ONE;

        pv_inject_hw_exception(TRAP_debug, X86_EVENT_NO_EC);

    }

}

/*

 * Local variables:

 * mode: C

 * c-file-style: "BSD"

 * c-basic-offset: 4

 * tab-width: 4

 * indent-tabs-mode: nil

 * End:

 */