libgcc/config/rs6000/tramp.S

   1 /*  Special support for trampolines
   2  *
   3  *   Copyright (C) 1996-2016 Free Software Foundation, Inc.
   4  *   Written By Michael Meissner
   5  *
   6  * This file is free software; you can redistribute it and/or modify it
   7  * under the terms of the GNU General Public License as published by the
   8  * Free Software Foundation; either version 3, or (at your option) any
   9  * later version.
  10  *
  11  * This file is distributed in the hope that it will be useful, but
  12  * WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14  * General Public License for more details.
  15  *
  16  * Under Section 7 of GPL version 3, you are granted additional
  17  * permissions described in the GCC Runtime Library Exception, version
  18  * 3.1, as published by the Free Software Foundation.
  19  *
  20  * You should have received a copy of the GNU General Public License and
  21  * a copy of the GCC Runtime Library Exception along with this program;
  22  * see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
  23  * <http://www.gnu.org/licenses/>.
  24  */
  25
  26 /* Set up trampolines.  */
  27
  28         .section ".text"
  29 #include "ppc-asm.h"
  30 #include "config.h"
  31
  32 #ifndef __powerpc64__
  33         .type   trampoline_initial,@object
  34         .align  2
  35 trampoline_initial:
  36         mflr    r0
  37         bcl     20,31,1f
  38 .Lfunc = .-trampoline_initial
  39         .long   0                       /* will be replaced with function address */
  40 .Lchain = .-trampoline_initial
  41         .long   0                       /* will be replaced with static chain */
  42 1:      mflr    r11
  43         mtlr    r0
  44         lwz     r0,0(r11)               /* function address */
  45         lwz     r11,4(r11)              /* static chain */
  46         mtctr   r0
  47         bctr
  48
  49 trampoline_size = .-trampoline_initial
  50         .size   trampoline_initial,trampoline_size
  51
  52
  53 /* R3 = stack address to store trampoline */
  54 /* R4 = length of trampoline area */
  55 /* R5 = function address */
  56 /* R6 = static chain */
  57
  58 FUNC_START(__trampoline_setup)
  59         mflr    r0              /* save return address */
  60         bcl     20,31,.LCF0     /* load up __trampoline_initial into r7 */
  61 .LCF0:
  62         mflr    r11
  63         addi    r7,r11,trampoline_initial-4-.LCF0 /* trampoline address -4 */
  64
  65         li      r8,trampoline_size      /* verify that the trampoline is big enough */
  66         cmpw    cr1,r8,r4
  67         srwi    r4,r4,2         /* # words to move */
  68         addi    r9,r3,-4        /* adjust pointer for lwzu */
  69         mtctr   r4
  70         blt     cr1,.Labort
  71
  72         mtlr    r0
  73
  74         /* Copy the instructions to the stack */
  75 .Lmove:
  76         lwzu    r10,4(r7)
  77         stwu    r10,4(r9)
  78         bdnz    .Lmove
  79
  80         /* Store correct function and static chain */
  81         stw     r5,.Lfunc(r3)
  82         stw     r6,.Lchain(r3)
  83
  84         /* Now flush both caches */
  85         mtctr   r4
  86 .Lcache:
  87         icbi    0,r3
  88         dcbf    0,r3
  89         addi    r3,r3,4
  90         bdnz    .Lcache
  91
  92         /* Finally synchronize things & return */
  93         sync
  94         isync
  95         blr
  96
  97 .Labort:
  98 /* Use a longcall sequence in the non PIC case on VxWorks, to prevent
  99    possible relocation errors if this is module-loaded very far away from
 100    the 'abort' entry point.  */
 101 #if defined (__VXWORKS__) && ! (defined __PIC__ || defined __pic__)
 102         lis   r11,JUMP_TARGET(abort)@ha
 103         addic r11,r11,JUMP_TARGET(abort)@l
 104         mtlr  r11
 105         blrl
 106 #else
 107
 108 #if (defined __PIC__ || defined __pic__) && defined HAVE_AS_REL16
 109         bcl     20,31,1f
 110 1:      mflr    r30
 111         addis   r30,r30,_GLOBAL_OFFSET_TABLE_-1b@ha
 112         addi    r30,r30,_GLOBAL_OFFSET_TABLE_-1b@l
 113 #endif
 114         bl      JUMP_TARGET(abort)
 115 FUNC_END(__trampoline_setup)
 116
 117 #endif
 118
 119 #elif _CALL_ELF == 2
 120         .type   trampoline_initial,@object
 121         .align  3
 122 trampoline_initial:
 123         ld      r11,.Lchain(r12)
 124         ld      r12,.Lfunc(r12)
 125         mtctr   r12
 126         bctr
 127 .Lfunc = .-trampoline_initial
 128         .quad   0                       /* will be replaced with function address */
 129 .Lchain = .-trampoline_initial
 130         .quad   0                       /* will be replaced with static chain */
 131
 132 trampoline_size = .-trampoline_initial
 133         .size   trampoline_initial,trampoline_size
 134
 135
 136 /* R3 = stack address to store trampoline */
 137 /* R4 = length of trampoline area */
 138 /* R5 = function address */
 139 /* R6 = static chain */
 140
 141         .pushsection ".toc","aw"
 142 .LC0:
 143         .quad   trampoline_initial-8
 144         .popsection
 145
 146 FUNC_START(__trampoline_setup)
 147         addis 7,2,.LC0@toc@ha
 148         ld 7,.LC0@toc@l(7)      /* trampoline address -8 */
 149
 150         li      r8,trampoline_size      /* verify that the trampoline is big enough */
 151         cmpw    cr1,r8,r4
 152         srwi    r4,r4,3         /* # doublewords to move */
 153         addi    r9,r3,-8        /* adjust pointer for stdu */
 154         mtctr   r4
 155         blt     cr1,.Labort
 156
 157         /* Copy the instructions to the stack */
 158 .Lmove:
 159         ldu     r10,8(r7)
 160         stdu    r10,8(r9)
 161         bdnz    .Lmove
 162
 163         /* Store correct function and static chain */
 164         std     r5,.Lfunc(r3)
 165         std     r6,.Lchain(r3)
 166
 167         /* Now flush both caches */
 168         mtctr   r4
 169 .Lcache:
 170         icbi    0,r3
 171         dcbf    0,r3
 172         addi    r3,r3,8
 173         bdnz    .Lcache
 174
 175         /* Finally synchronize things & return */
 176         sync
 177         isync
 178         blr
 179
 180 .Labort:
 181         bl      JUMP_TARGET(abort)
 182         nop
 183 FUNC_END(__trampoline_setup)
 184
 185 #endif