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root/kernel/arch/sparc64/src/sun4v/asm.S

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#
# Copyright (c) 2008 Pavel Rimsky
# All rights reserved.
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions
# are met:
#
# - Redistributions of source code must retain the above copyright
#   notice, this list of conditions and the following disclaimer.
# - 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.
# - The name of the author may not be used to endorse or promote products
#   derived from this software without specific prior written permission.
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# THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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# NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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#include <abi/asmtool.h>
#include <arch/mm/mmu.h>
#include <arch/regdef.h>
#include <arch/stack.h>

.text

/** Switch to userspace.
 *
 * %o0  Userspace entry address.
 * %o1  Userspace stack pointer address.
 * %o2  Userspace address of uarg structure.
 */
FUNCTION_BEGIN(switch_to_userspace)
        save %o1, 0, %sp
        flushw
        wrpr %g0, 0, %cleanwin          ! avoid information leak

        mov %i2, %o0                    ! uarg
        xor %o1, %o1, %o1               ! %o1 is defined to hold pcb_ptr
                                        ! set it to 0
        clr %i2
        clr %i3
        clr %i4
        clr %i5
        clr %i6
        wrpr %g0, 1, %tl                ! enforce mapping via nucleus

        rdpr %cwp, %g1
        wrpr %g1, TSTATE_IE_BIT, %tstate
        wrpr %i0, 0, %tnpc

        /*
         * Set primary context according to secondary context.
         * Secondary context has been already installed by
         * higher-level functions.
         */
        wr %g0, ASI_SECONDARY_CONTEXT_REG, %asi
        ldxa [VA_SECONDARY_CONTEXT_REG] %asi, %g1
        wr %g0, ASI_PRIMARY_CONTEXT_REG, %asi
        stxa %g1, [VA_PRIMARY_CONTEXT_REG] %asi
        flush %i7

        /*
         * Spills and fills will be handled by the userspace handlers.
         */
        wrpr %g0, WSTATE_OTHER(0) | WSTATE_NORMAL(1), %wstate
        done                            ! jump to userspace
FUNCTION_END(switch_to_userspace)

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