sys/mips/mips/stack_machdep.c

   1 /*-
   2  * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
   3  *
   4  * Copyright (c) 2005 Antoine Brodin
   5  * All rights reserved.
   6  *
   7  * Redistribution and use in source and binary forms, with or without
   8  * modification, are permitted provided that the following conditions
   9  * are met:
  10  * 1. Redistributions of source code must retain the above copyright
  11  *    notice, this list of conditions and the following disclaimer.
  12  * 2. Redistributions in binary form must reproduce the above copyright
  13  *    notice, this list of conditions and the following disclaimer in the
  14  *    documentation and/or other materials provided with the distribution.
  15  *
  16  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  17  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  18  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  19  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  20  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  21  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  22  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  23  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  24  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  25  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  26  * SUCH DAMAGE.
  27  */
  28
  29 #include <sys/cdefs.h>
  30 __FBSDID("$FreeBSD$");
  31
  32 #include <sys/types.h>
  33 #include <sys/systm.h>
  34 #include <sys/param.h>
  35 #include <sys/proc.h>
  36 #include <sys/stack.h>
  37
  38 #include <machine/mips_opcode.h>
  39
  40 #include <machine/pcb.h>
  41 #include <machine/regnum.h>
  42
  43 static u_register_t
  44 stack_register_fetch(u_register_t sp, u_register_t stack_pos)
  45 {
  46         u_register_t * stack =
  47             ((u_register_t *)(intptr_t)sp + (size_t)stack_pos/sizeof(u_register_t));
  48
  49         return *stack;
  50 }
  51
  52 static void
  53 stack_capture(struct stack *st, u_register_t pc, u_register_t sp)
  54 {
  55         u_register_t  ra = 0, i, stacksize;
  56         short ra_stack_pos = 0;
  57         InstFmt insn;
  58
  59         stack_zero(st);
  60
  61         for (;;) {
  62                 stacksize = 0;
  63                 if (pc <= (u_register_t)(intptr_t)btext)
  64                         break;
  65                 for (i = pc; i >= (u_register_t)(intptr_t)btext; i -= sizeof (insn)) {
  66                         bcopy((void *)(intptr_t)i, &insn, sizeof insn);
  67                         switch (insn.IType.op) {
  68                         case OP_ADDI:
  69                         case OP_ADDIU:
  70                         case OP_DADDI:
  71                         case OP_DADDIU:
  72                                 if (insn.IType.rs != SP || insn.IType.rt != SP)
  73                                         break;
  74                                 stacksize = -(short)insn.IType.imm;
  75                                 break;
  76
  77                         case OP_SW:
  78                         case OP_SD:
  79                                 if (insn.IType.rs != SP || insn.IType.rt != RA)
  80                                         break;
  81                                 ra_stack_pos = (short)insn.IType.imm;
  82                                 break;
  83                         default:
  84                                 break;
  85                         }
  86
  87                         if (stacksize)
  88                                 break;
  89                 }
  90
  91                 if (stack_put(st, pc) == -1)
  92                         break;
  93
  94                 for (i = pc; !ra; i += sizeof (insn)) {
  95                         bcopy((void *)(intptr_t)i, &insn, sizeof insn);
  96
  97                         switch (insn.IType.op) {
  98                         case OP_SPECIAL:
  99                                 if (insn.RType.func == OP_JR) {
 100                                         if (ra >= (u_register_t)(intptr_t)btext)
 101                                                 break;
 102                                         if (insn.RType.rs != RA)
 103                                                 break;
 104                                         ra = stack_register_fetch(sp,
 105                                             ra_stack_pos);
 106                                         if (!ra)
 107                                                 goto done;
 108                                         ra -= 8;
 109                                 }
 110                                 break;
 111                         default:
 112                                 break;
 113                         }
 114                         /* eret */
 115                         if (insn.word == 0x42000018)
 116                                 goto done;
 117                 }
 118
 119                 if (pc == ra && stacksize == 0)
 120                         break;
 121
 122                 sp += stacksize;
 123                 pc = ra;
 124                 ra = 0;
 125         }
 126 done:
 127         return;
 128 }
 129
 130 void
 131 stack_save_td(struct stack *st, struct thread *td)
 132 {
 133         u_register_t pc, sp;
 134
 135         if (TD_IS_SWAPPED(td))
 136                 panic("stack_save_td: swapped");
 137         if (TD_IS_RUNNING(td))
 138                 panic("stack_save_td: running");
 139
 140         pc = td->td_pcb->pcb_regs.pc;
 141         sp = td->td_pcb->pcb_regs.sp;
 142         stack_capture(st, pc, sp);
 143 }
 144
 145 int
 146 stack_save_td_running(struct stack *st, struct thread *td)
 147 {
 148
 149         return (EOPNOTSUPP);
 150 }
 151
 152 void
 153 stack_save(struct stack *st)
 154 {
 155         u_register_t pc, sp;
 156
 157         if (curthread == NULL)
 158                 panic("stack_save: curthread == NULL");
 159
 160         pc = curthread->td_pcb->pcb_regs.pc;
 161         sp = curthread->td_pcb->pcb_regs.sp;
 162         stack_capture(st, pc, sp);
 163 }