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#
# Copyright (C) 2005 Jakub Jermar
# 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.
#
# 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,
# 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.
#

#include <arch/stack.h>
#include <arch/regdef.h>
#include <arch/mm/mmu.h>

.text

.global memcpy
.global memcpy_from_uspace
.global memcpy_to_uspace
.global memcpy_from_uspace_failover_address
.global memcpy_to_uspace_failover_address
.global memsetb


memcpy:
memcpy_from_uspace:
memcpy_to_uspace:
    .register       %g2, #scratch
        .register       %g3, #scratch
    add %o1, 7, %g1
    and %g1, -8, %g1
    cmp %o1, %g1
    be,pn   %xcc, 3f
    add %o0, 7, %g1
    mov 0, %g3
0:
    brz,pn  %o2, 2f
    mov 0, %g2
1:
    ldub    [%g3 + %o1], %g1
    add %g2, 1, %g2
    cmp %o2, %g2
    stb %g1, [%g3 + %o0]
    bne,pt  %xcc, 1b
    mov %g2, %g3
2:
    jmp %o7 + 8         ! exit point
    mov %o1, %o0
3:
    and %g1, -8, %g1
    cmp %o0, %g1
    bne,pt  %xcc, 0b
    mov 0, %g3
    srlx    %o2, 3, %g4
    brz,pn  %g4, 5f
    mov 0, %g5
4:
    sllx    %g3, 3, %g2
    add %g5, 1, %g3
    ldx [%o1 + %g2], %g1
    mov %g3, %g5
    cmp %g4, %g3
    bne,pt  %xcc, 4b
    stx %g1, [%o0 + %g2]
5:
    and %o2, 7, %o2
    brz,pn  %o2, 2b
    sllx    %g4, 3, %g1
    mov 0, %g2
    add %g1, %o0, %o0
    add %g1, %o1, %g4
    mov 0, %g3
6:
    ldub    [%g2 + %g4], %g1
    stb %g1, [%g2 + %o0]
    add %g3, 1, %g2
    cmp %o2, %g2
    bne,pt  %xcc, 6b
    mov %g2, %g3

    jmp %o7 + 8         ! exit point
    mov %o1, %o0

memcpy_from_uspace_failover_address:
memcpy_to_uspace_failover_address:
    jmp %o7 + 8         ! exit point
    mov %g0, %o0        ! return 0 on failure

memsetb:
    b _memsetb
    nop


.macro WRITE_ALTERNATE_REGISTER reg, bit
    save %sp, -STACK_WINDOW_SAVE_AREA_SIZE, %sp
    rdpr %pstate, %l0
    wrpr %l0, \bit, %pstate
    mov %i0, \reg
    wrpr %l0, 0, %pstate
    ret
    restore
.endm

.macro READ_ALTERNATE_REGISTER reg, bit
    save %sp, -STACK_WINDOW_SAVE_AREA_SIZE, %sp
    rdpr %pstate, %l0
    wrpr %l0, \bit, %pstate
    mov \reg, %i0
    wrpr %l0, 0, %pstate
    ret
    restore
.endm

.global write_to_ag_g6
write_to_ag_g6:
    WRITE_ALTERNATE_REGISTER %g6, PSTATE_AG_BIT

.global write_to_ag_g7
write_to_ag_g7:
    WRITE_ALTERNATE_REGISTER %g7, PSTATE_AG_BIT

.global write_to_ig_g6
write_to_ig_g6:
    WRITE_ALTERNATE_REGISTER %g6, PSTATE_IG_BIT

.global read_from_ag_g7
read_from_ag_g7:
    READ_ALTERNATE_REGISTER %g7, PSTATE_AG_BIT


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

    mov %i3, %o0            ! uarg

    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_DMMU, %asi
    ldxa [VA_SECONDARY_CONTEXT_REG] %asi, %g1
    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