sys/mips/mips/stack_machdep.c

   1 /*-
   2  * Copyright (c) 2005 Antoine Brodin
   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  * 1. Redistributions of source code must retain the above copyright
   9  *    notice, this list of conditions and the following disclaimer.
  10  * 2. Redistributions in binary form must reproduce the above copyright
  11  *    notice, this list of conditions and the following disclaimer in the
  12  *    documentation and/or other materials provided with the distribution.
  13  *
  14  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  15  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  16  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  17  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  18  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  19  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  20  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  21  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  22  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  23  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  24  * SUCH DAMAGE.
  25  */
  26
  27 #include <sys/cdefs.h>
  28 __FBSDID("$FreeBSD$");
  29
  30 #include <sys/types.h>
  31 #include <sys/systm.h>
  32 #include <sys/param.h>
  33 #include <sys/proc.h>
  34 #include <sys/stack.h>
  35
  36 #include <machine/mips_opcode.h>
  37
  38 #include <machine/param.h>
  39 #include <machine/pcb.h>
  40 #include <machine/regnum.h>
  41
  42 static u_register_t
  43 stack_register_fetch(u_register_t sp, u_register_t stack_pos)
  44 {
  45         u_register_t * stack =
  46             ((u_register_t *)sp + stack_pos/sizeof(u_register_t));
  47
  48         return *stack;
  49 }
  50
  51 static void
  52 stack_capture(struct stack *st, u_register_t pc, u_register_t sp)
  53 {
  54         u_register_t  ra = 0, i, stacksize;
  55         short ra_stack_pos = 0;
  56         InstFmt insn;
  57
  58         stack_zero(st);
  59
  60         for (;;) {
  61                 stacksize = 0;
  62                 if (pc <= (u_register_t)btext)
  63                         break;
  64                 for (i = pc; i >= (u_register_t)btext; i -= sizeof (insn)) {
  65                         bcopy((void *)i, &insn, sizeof insn);
  66                         switch (insn.IType.op) {
  67                         case OP_ADDI:
  68                         case OP_ADDIU:
  69                                 if (insn.IType.rs != SP || insn.IType.rt != SP)
  70                                         break;
  71                                 stacksize = -(short)insn.IType.imm;
  72                                 break;
  73
  74                         case OP_SW:
  75                                 if (insn.IType.rs != SP || insn.IType.rt != RA)
  76                                         break;
  77                                 ra_stack_pos = (short)insn.IType.imm;
  78                                 break;
  79                         default:
  80                                 break;
  81                         }
  82
  83                         if (stacksize)
  84                                 break;
  85                 }
  86
  87                 if (stack_put(st, pc) == -1)
  88                         break;
  89
  90                 for (i = pc; !ra; i += sizeof (insn)) {
  91                         bcopy((void *)i, &insn, sizeof insn);
  92
  93                         switch (insn.IType.op) {
  94                         case OP_SPECIAL:
  95                                 if((insn.RType.func == OP_JR))
  96                                 {
  97                                         if (ra >= (u_register_t)btext)
  98                                                 break;
  99                                         if (insn.RType.rs != RA)
 100                                                 break;
 101                                         ra = stack_register_fetch(sp,
 102                                             ra_stack_pos);
 103                                         if (!ra)
 104                                                 goto done;
 105                                         ra -= 8;
 106                                 }
 107                                 break;
 108                         default:
 109                                 break;
 110                         }
 111                         /* eret */
 112                         if (insn.word == 0x42000018)
 113                                 goto done;
 114                 }
 115
 116                 if (pc == ra && stacksize == 0)
 117                         break;
 118
 119                 sp += stacksize;
 120                 pc = ra;
 121                 ra = 0;
 122         }
 123 done:
 124         return;
 125 }
 126
 127 void
 128 stack_save_td(struct stack *st, struct thread *td)
 129 {
 130         u_register_t pc, sp;
 131
 132         if (TD_IS_SWAPPED(td))
 133                 panic("stack_save_td: swapped");
 134         if (TD_IS_RUNNING(td))
 135                 panic("stack_save_td: running");
 136
 137         pc = td->td_pcb->pcb_regs.pc;
 138         sp = td->td_pcb->pcb_regs.sp;
 139         stack_capture(st, pc, sp);
 140 }
 141
 142 void
 143 stack_save(struct stack *st)
 144 {
 145         u_register_t pc, sp;
 146
 147         if (curthread == NULL)
 148                 panic("stack_save: curthread == NULL)");
 149
 150         pc = curthread->td_pcb->pcb_regs.pc;
 151         sp = curthread->td_pcb->pcb_regs.sp;
 152         stack_capture(st, pc, sp);
 153 }