sysdeps/unix/sysv/linux/mips/makecontext.S

   1 /* Modify saved context.
   2    Copyright (C) 2009-2015 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4    Contributed by Maciej W. Rozycki <macro@codesourcery.com>.
   5
   6    The GNU C Library is free software; you can redistribute it and/or
   7    modify it under the terms of the GNU Lesser General Public
   8    License as published by the Free Software Foundation; either
   9    version 2.1 of the License, or (at your option) any later version.
  10
  11    The GNU C Library is distributed in the hope that it will be useful,
  12    but WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14    Lesser General Public License for more details.
  15
  16    You should have received a copy of the GNU Lesser General Public
  17    License along with the GNU C Library.  If not, see
  18    <http://www.gnu.org/licenses/>.  */
  19
  20 #include <sysdep.h>
  21 #include <sys/asm.h>
  22 #include <sys/fpregdef.h>
  23 #include <sys/regdef.h>
  24
  25 #include "ucontext_i.h"
  26
  27 /* int makecontext (ucontext_t *ucp, (void *func) (), int argc, ...) */
  28
  29         .text
  30         .set    nomips16
  31 LOCALSZ = 0
  32 ARGSZ = 0
  33 MASK = 0x00000000
  34 #ifdef __PIC__
  35 LOCALSZ = 1                                             /* save gp */
  36 #endif
  37 #if _MIPS_SIM != _ABIO32
  38 ARGSZ = 5                                               /* save a3-a7 */
  39 # ifdef __PIC__
  40 MASK = 0x10000000
  41 # endif
  42 #endif
  43 FRAMESZ = (((ARGSZ + LOCALSZ) * SZREG) + ALSZ) & ALMASK
  44 GPOFF = FRAMESZ - ((ARGSZ + 1) * SZREG)
  45 #if _MIPS_SIM != _ABIO32
  46 A3OFF = FRAMESZ - (5 * SZREG)                           /* callee-allocated */
  47 A4OFF = FRAMESZ - (4 * SZREG)
  48 A5OFF = FRAMESZ - (3 * SZREG)
  49 A6OFF = FRAMESZ - (2 * SZREG)
  50 A7OFF = FRAMESZ - (1 * SZREG)
  51 NARGREGS = 8
  52 #else
  53 A3OFF = FRAMESZ + (3 * SZREG)                           /* caller-allocated */
  54 NARGREGS = 4
  55 #endif
  56
  57 NESTED (__makecontext, FRAMESZ, ra)
  58         .mask   MASK, -(ARGSZ * SZREG)
  59         .fmask  0x00000000, 0
  60
  61 98:
  62 #ifdef __PIC__
  63         SETUP_GP
  64 #endif
  65
  66         PTR_ADDIU sp, -FRAMESZ
  67         cfi_adjust_cfa_offset (FRAMESZ)
  68
  69 #ifdef __PIC__
  70         SETUP_GP64_STACK (GPOFF, __makecontext)
  71         SAVE_GP (GPOFF)
  72 #endif
  73
  74 #ifdef PROF
  75         .set    noat
  76         move    AT, ra
  77         jal     _mcount
  78         .set    at
  79 #endif
  80
  81         /* Store args to be passed.  */
  82         REG_S   a3, A3OFF(sp)
  83 #if _MIPS_SIM != _ABIO32
  84         REG_S   a4, A4OFF(sp)
  85         REG_S   a5, A5OFF(sp)
  86         REG_S   a6, A6OFF(sp)
  87         REG_S   a7, A7OFF(sp)
  88 #endif
  89
  90         /* Store a magic flag.  */
  91         li      v1, 1
  92         REG_S   v1, (0 * SZREG + MCONTEXT_GREGS)(a0)    /* zero */
  93
  94         /* Set up the stack.  */
  95         PTR_L   t0, STACK_SP(a0)
  96         PTR_L   t2, STACK_SIZE(a0)
  97         PTR_ADDIU t1, sp, A3OFF
  98         PTR_ADDU t0, t2
  99         and     t0, ALMASK
 100         blez    a2, 2f                                  /* no arguments */
 101
 102         /* Store register arguments.  */
 103         PTR_ADDIU t2, a0, MCONTEXT_GREGS + 4 * SZREG
 104         move    t3, zero
 105 0:
 106         addiu   t3, 1
 107         REG_L   v1, (t1)
 108         PTR_ADDIU t1, SZREG
 109         REG_S   v1, (t2)
 110         PTR_ADDIU t2, SZREG
 111         bgeu    t3, a2, 2f                              /* all done */
 112         bltu    t3, NARGREGS, 0b                        /* next */
 113
 114         /* Make room for stack arguments.  */
 115         PTR_SUBU t2, a2, t3
 116         PTR_SLL t2, 3
 117         PTR_SUBU t0, t2
 118         and     t0, ALMASK
 119
 120         /* Store stack arguments.  */
 121         move    t2, t0
 122 1:
 123         addiu   t3, 1
 124         REG_L   v1, (t1)
 125         PTR_ADDIU t1, SZREG
 126         REG_S   v1, (t2)
 127         PTR_ADDIU t2, SZREG
 128         bltu    t3, a2, 1b                              /* next */
 129
 130 2:
 131 #if _MIPS_SIM == _ABIO32
 132         /* Make room for a0-a3 storage.  */
 133         PTR_ADDIU t0, -(NARGSAVE * SZREG)
 134 #endif
 135         PTR_L   v1, UCONTEXT_LINK(a0)
 136 #ifdef __PIC__
 137         PTR_ADDIU t9, 99f - 98b
 138 #else
 139         PTR_LA  t9, 99f
 140 #endif
 141         REG_S   t0, (29 * SZREG + MCONTEXT_GREGS)(a0)   /* sp */
 142         REG_S   v1, (16 * SZREG + MCONTEXT_GREGS)(a0)   /* s0 */
 143 #ifdef __PIC__
 144         REG_S   gp, (17 * SZREG + MCONTEXT_GREGS)(a0)   /* s1 */
 145 #endif
 146         REG_S   t9, (31 * SZREG + MCONTEXT_GREGS)(a0)   /* ra */
 147         REG_S   a1, MCONTEXT_PC(a0)
 148
 149 #ifdef __PIC__
 150         RESTORE_GP64_STACK
 151         PTR_ADDIU sp, FRAMESZ
 152         cfi_adjust_cfa_offset (-FRAMESZ)
 153 #endif
 154         jr      ra
 155
 156 99:
 157 #ifdef __PIC__
 158         move    gp, s1
 159 #endif
 160         move    a0, zero
 161         beqz    s0, 0f
 162
 163         /* setcontext (ucp) */
 164         move    a0, s0
 165 #ifdef __PIC__
 166         PTR_LA  t9, JUMPTARGET (__setcontext)
 167         jalr    t9
 168 # if _MIPS_SIM == _ABIO32
 169         move    gp, s1
 170 # endif
 171 #else
 172         jal     JUMPTARGET (__setcontext)
 173 #endif
 174         move    a0, v0
 175
 176 0:
 177         /* exit (a0) */
 178 #ifdef __PIC__
 179         PTR_LA  t9, HIDDEN_JUMPTARGET (exit)
 180         jalr    t9
 181 #else
 182         jal     HIDDEN_JUMPTARGET (exit)
 183 #endif
 184
 185         /* You don't exist, you won't feel anything.  */
 186 1:
 187         lb      zero, (zero)
 188         b       1b
 189 PSEUDO_END (__makecontext)
 190
 191 weak_alias (__makecontext, makecontext)