/*      $NetBSD: rtld_start.S,v 1.17 2011/09/26 01:52:22 mrg Exp $      */

/*-
 * Copyright (C) 1998   Tsubai Masanari
 * Portions copyright 2002 Charles M. Hannum <root@ihack.net>
 * 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. 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 <machine/asm.h>

        .globl  _rtld_start
        .globl  _rtld

        .text

_rtld_start:
        stwu    %r1,-48(%r1)
        stw     %r3,12(%r1)             # argc
        stw     %r4,16(%r1)             # argv
        stw     %r5,20(%r1)             # envp
/*      stw     %r6,24(%r1)             # obj           (always 0) */
/*      stw     %r7,28(%r1)             # cleanup       (always 0) */
        stw     %r8,32(%r1)             # ps_strings

        bcl     20,31,1f
1:      mflr    %r30
        mr      %r3,%r30                # save for _DYNAMIC
        addis   %r30,%r30,_GLOBAL_OFFSET_TABLE_-1b@ha
        addi    %r30,%r30,_GLOBAL_OFFSET_TABLE_-1b@l
        addis   %r3,%r3,_DYNAMIC-1b@ha  # get _DYNAMIC actual address
        addi    %r3,%r3,_DYNAMIC-1b@l
        lwz     %r28,0(%r30)            # get base-relative &_DYNAMIC
        sub     %r28,%r3,%r28           # r28 = relocbase
        mr      %r4,%r28                # r4 = relocbase
        bl      _rtld_relocate_nonplt_self

        lwz     %r3,16(%r1)
        addi    %r3,%r3,-12             # sp = &argv[-3]        /* XXX */
        mr      %r4,%r28                # r4 = relocbase
        bl      _rtld                   # _start = _rtld(sp, relocbase)
        mtlr    %r3

        lwz     %r3,12(%r1)             # argc
        lwz     %r4,16(%r1)             # argv
        lwz     %r5,20(%r1)             # envp
        lwz     %r6,-8(%r4)             # obj = sp[1] (== argv[-2])
        lwz     %r7,-12(%r4)            # cleanup = sp[0] (== argv[-3])
        lwz     %r8,32(%r1)             # ps_strings

        addi    %r1,%r1,48
        blrl            # _start(argc, argv, envp, obj, cleanup, ps_strings)

        li      %r0,1                   # _exit()
        sc

END(_rtld_start)

        .globl  _rtld_bind

/*
 * secure-plt expects %r11 to be the offset to the rela entry.
 * bss-plt expects %r11 to be index of the rela entry.
 * So for bss-plt, we multiply the index by 12 to get the offset.
 */
ENTRY_NOPROFILE(_rtld_bind_secureplt_start)
        stwu    %r1,-160(%r1)
        stw     %r0,20(%r1)

        /*
         * Instead of division which is costly we will use multiplicative
         * inverse.  a / n = ((a * inv(n)) >> 32)
         * where inv(n) = (0x100000000 + n - 1) / n
         */
        mr      %r0,%r11
        lis     %r11,0x15555556@h       # load multiplicative inverse of 12
        ori     %r11,%r11,0x15555556@l
        mulhwu  %r11,%r11,%r0           # get high half of multiplication

        b       1f
ENTRY_NOPROFILE(_rtld_bind_bssplt_start)
        stwu    %r1,-160(%r1)

        stw     %r0,20(%r1)
1:
        mflr    %r0
        stw     %r0,16(%r1)             # save lr
        mfcr    %r0
        stw     %r0,12(%r1)             # save cr
        stmw    %r3,24(%r1)             # save r3-r31

        mr      %r3,%r12                # obj
        mr      %r4,%r11                # reloff
        bl      _rtld_bind              # _rtld_bind(obj, reloff)
        mtctr   %r3

        lmw     %r3,24(%r1)             # load r3-r31
        lwz     %r0,12(%r1)             # restore cr
        mtcr    %r0
        lwz     %r0,16(%r1)             # restore lr
        mtlr    %r0
        lwz     %r0,20(%r1)

        addi    %r1,%r1,160
        bctr
END(_rtld_bind_secureplt_start)

        .globl  _rtld_powerpc_pltcall
        .globl  _rtld_powerpc_pltresolve

_rtld_powerpc_pltcall:
        slwi    %r11,%r11,2
        addis   %r11,%r11,0             # addis 11,11,jmptab@ha
        lwz     %r11,0(%r11)            # lwz   11,jmptab@l(11)
        mtctr   %r11
        bctr

_rtld_powerpc_pltresolve:
        lis     %r12,0                  # lis   12,_rtld_bind_bssplt_start@ha
        addi    %r12,%r12,0             # addi  12,12,_rtld_bind_bssplt_start@l
        mtctr   %r12
        lis     %r12,0                  # lis   12,obj@ha
        addi    %r12,%r12,0             # addi  12,12,obj@l
        bctr