libgcc/config/rs6000/tramp.S

   1 /*  Special support for trampolines
   2  *
   3  *   Copyright (C) 1996-2024 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         .cfi_startproc
  60         mflr    r0              /* save return address */
  61         bcl     20,31,.LCF0     /* load up __trampoline_initial into r7 */
  62         .cfi_register lr,r0
  63 .LCF0:
  64         mflr    r11
  65         addi    r7,r11,trampoline_initial-4-.LCF0 /* trampoline address -4 */
  66
  67         cmpwi   cr1,r4,trampoline_size  /* verify that the trampoline is big enough */
  68         srwi    r4,r4,2         /* # words to move */
  69         addi    r9,r3,-4        /* adjust pointer for lwzu */
  70         mtctr   r4
  71         blt     cr1,.Labort
  72
  73         mtlr    r0
  74
  75         /* Copy the instructions to the stack */
  76 .Lmove:
  77         lwzu    r10,4(r7)
  78         stwu    r10,4(r9)
  79         bdnz    .Lmove
  80
  81         /* Store correct function and static chain */
  82         stw     r5,.Lfunc(r3)
  83         stw     r6,.Lchain(r3)
  84
  85         /* Now flush both caches */
  86         mtctr   r4
  87 .Lcache:
  88         icbi    0,r3
  89         dcbf    0,r3
  90         addi    r3,r3,4
  91         bdnz    .Lcache
  92
  93         /* Finally synchronize things & return */
  94         sync
  95         isync
  96         blr
  97
  98 .Labort:
  99 /* Use a longcall sequence in the non PIC case on VxWorks, to prevent
 100    possible relocation errors if this is module-loaded very far away from
 101    the 'abort' entry point.  */
 102 #if defined (__VXWORKS__) && ! (defined __PIC__ || defined __pic__)
 103         lis   r11,JUMP_TARGET(abort)@ha
 104         addic r11,r11,JUMP_TARGET(abort)@l
 105         mtlr  r11
 106         blrl
 107 #else
 108
 109 #if (defined __PIC__ || defined __pic__) && defined HAVE_AS_REL16
 110         bcl     20,31,1f
 111 1:      mflr    r30
 112         addis   r30,r30,_GLOBAL_OFFSET_TABLE_-1b@ha
 113         addi    r30,r30,_GLOBAL_OFFSET_TABLE_-1b@l
 114 #endif
 115         bl      JUMP_TARGET(abort)
 116 #endif
 117         .cfi_endproc
 118 FUNC_END(__trampoline_setup)
 119
 120 #elif _CALL_ELF == 2
 121         .type   trampoline_initial,@object
 122         .align  3
 123 trampoline_initial:
 124         ld      r11,.Lchain(r12)
 125         ld      r12,.Lfunc(r12)
 126         mtctr   r12
 127         bctr
 128 .Lfunc = .-trampoline_initial
 129         .quad   0                       /* will be replaced with function address */
 130 .Lchain = .-trampoline_initial
 131         .quad   0                       /* will be replaced with static chain */
 132
 133 trampoline_size = .-trampoline_initial
 134         .size   trampoline_initial,trampoline_size
 135
 136
 137 /* R3 = stack address to store trampoline */
 138 /* R4 = length of trampoline area */
 139 /* R5 = function address */
 140 /* R6 = static chain */
 141
 142 #ifndef __PCREL__
 143         .pushsection ".toc","aw"
 144 .LC0:
 145         .quad   trampoline_initial-8
 146         .popsection
 147 #endif
 148
 149 FUNC_START(__trampoline_setup)
 150         .cfi_startproc
 151 #ifdef __PCREL__
 152         pla 7,(trampoline_initial-8)@pcrel
 153 #else
 154         addis 7,2,.LC0@toc@ha
 155         ld 7,.LC0@toc@l(7)      /* trampoline address -8 */
 156 #endif
 157
 158         cmpwi   cr1,r4,trampoline_size  /* verify that the trampoline is big enough */
 159         srwi    r4,r4,3         /* # doublewords to move */
 160         addi    r9,r3,-8        /* adjust pointer for stdu */
 161         mtctr   r4
 162         blt     cr1,.Labort
 163
 164         /* Copy the instructions to the stack */
 165 .Lmove:
 166         ldu     r10,8(r7)
 167         stdu    r10,8(r9)
 168         bdnz    .Lmove
 169
 170         /* Store correct function and static chain */
 171         std     r5,.Lfunc(r3)
 172         std     r6,.Lchain(r3)
 173
 174         /* Now flush both caches */
 175         mtctr   r4
 176 .Lcache:
 177         icbi    0,r3
 178         dcbf    0,r3
 179         addi    r3,r3,8
 180         bdnz    .Lcache
 181
 182         /* Finally synchronize things & return */
 183         sync
 184         isync
 185         blr
 186
 187 .Labort:
 188         bl      JUMP_TARGET(abort)
 189         nop
 190         .cfi_endproc
 191 FUNC_END(__trampoline_setup)
 192
 193 #endif