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      1 /*
      2  * Copyright (C) 2012 The Android Open Source Project
      3  * All rights reserved.
      4  *
      5  * Redistribution and use in source and binary forms, with or without
      6  * modification, are permitted provided that the following conditions
      7  * are met:
      8  *  * Redistributions of source code must retain the above copyright
      9  *    notice, this list of conditions and the following disclaimer.
     10  *  * Redistributions in binary form must reproduce the above copyright
     11  *    notice, this list of conditions and the following disclaimer in
     12  *    the documentation and/or other materials provided with the
     13  *    distribution.
     14  *
     15  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
     16  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
     17  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
     18  * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
     19  * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
     20  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
     21  * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
     22  * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
     23  * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
     24  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
     25  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     26  * SUCH DAMAGE.
     27  */
     28 
     29     .text
     30     .align    4
     31     .type    __start,@function
     32 
     33     .ent    __start
     34     .globl    __start
     35     .globl    _start
     36 __start:
     37 _start:
     38     .set    noreorder
     39     bal    1f
     40     nop
     41 1:  .cpload    $31
     42     .set    reorder
     43 
     44     /* Discover the load address */
     45     la    $t0, 1f
     46     bal    1f
     47 1:  subu    $t0, $ra, $t0
     48 
     49 #define DT_PLTGOT 3
     50 #define DT_MIPS_LOCAL_GOTNO 0x7000000a
     51 
     52     /* Search dynamic table for DT_MIPS_LOCAL_GOTNO and DT_PLTGOT values */
     53     la    $t1, _DYNAMIC
     54     addu    $t1, $t0
     55     li    $t3, DT_PLTGOT
     56     li    $t4, DT_MIPS_LOCAL_GOTNO
     57 0:
     58     lw    $t2, 0($t1)
     59     beqz    $t2, .Lrelocate_local_got
     60 
     61     bne    $t2, $t3, 1f    /* DT_PLTGOT? */
     62     lw    $s0, 4($t1)
     63     addu    $s0, $t0
     64     b    2f
     65 
     66 1:  bne    $t2, $t4, 1f    /* DT_MIPS_LOCAL_GOTNO? */
     67     lw    $s1, 4($t1)
     68     b    2f
     69 
     70 1:
     71 2:  addu    $t1, 8
     72     b    0b
     73 
     74 .Lrelocate_local_got:
     75     /*
     76      * Relocate the local GOT entries
     77      * got[0] is address of lazy resolver function
     78      * got[1] may be used for a GNU extension
     79      */
     80 
     81     addu    $s0, 4
     82     subu    $s1, 1
     83     lw    $t1, ($s0)
     84     bgez    $t1, 9f
     85     addu    $s0, 4
     86     subu    $s1, 1
     87     b    9f
     88 
     89 1:  lw    $t1, ($s0)
     90     addu    $t1, $t0
     91     sw    $t1, ($s0)
     92     addu    $s0, 4
     93 9:  subu    $s1, 1
     94     bgez    $s1, 1b
     95 
     96     /* call linker_init */
     97     move    $a0, $sp
     98     addiu    $sp, -4*4        /* space for arg saves in linker_init */
     99     la    $t9, __linker_init
    100     jalr    $t9
    101     move    $t9, $v0
    102     addu    $sp, 4*4        /* restore sp */
    103     j    $t9
    104     .end    __start
    105