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/param.h>
  33 #include <sys/systm.h>
  34 #include <sys/lock.h>
  35 #include <sys/mutex.h>
  36 #include <sys/proc.h>
  37 #include <sys/stack.h>
  38
  39 #include <machine/mips_opcode.h>
  40
  41 #include <machine/pcb.h>
  42 #include <machine/regnum.h>
  43
  44 static u_register_t
  45 stack_register_fetch(u_register_t sp, u_register_t stack_pos)
  46 {
  47         u_register_t * stack =
  48             ((u_register_t *)(intptr_t)sp + (size_t)stack_pos/sizeof(u_register_t));
  49
  50         return *stack;
  51 }
  52
  53 static void
  54 stack_capture(struct stack *st, u_register_t pc, u_register_t sp)
  55 {
  56         u_register_t  ra = 0, i, stacksize;
  57         short ra_stack_pos = 0;
  58         InstFmt insn;
  59
  60         stack_zero(st);
  61
  62         for (;;) {
  63                 stacksize = 0;
  64                 if (pc <= (u_register_t)(intptr_t)btext)
  65                         break;
  66                 for (i = pc; i >= (u_register_t)(intptr_t)btext; i -= sizeof (insn)) {
  67                         bcopy((void *)(intptr_t)i, &insn, sizeof insn);
  68                         switch (insn.IType.op) {
  69                         case OP_ADDI:
  70                         case OP_ADDIU:
  71                         case OP_DADDI:
  72                         case OP_DADDIU:
  73                                 if (insn.IType.rs != SP || insn.IType.rt != SP)
  74                                         break;
  75                                 stacksize = -(short)insn.IType.imm;
  76                                 break;
  77
  78                         case OP_SW:
  79                         case OP_SD:
  80                                 if (insn.IType.rs != SP || insn.IType.rt != RA)
  81                                         break;
  82                                 ra_stack_pos = (short)insn.IType.imm;
  83                                 break;
  84                         default:
  85                                 break;
  86                         }
  87
  88                         if (stacksize)
  89                                 break;
  90                 }
  91
  92                 if (stack_put(st, pc) == -1)
  93                         break;
  94
  95                 for (i = pc; !ra; i += sizeof (insn)) {
  96                         bcopy((void *)(intptr_t)i, &insn, sizeof insn);
  97
  98                         switch (insn.IType.op) {
  99                         case OP_SPECIAL:
 100                                 if (insn.RType.func == OP_JR) {
 101                                         if (ra >= (u_register_t)(intptr_t)btext)
 102                                                 break;
 103                                         if (insn.RType.rs != RA)
 104                                                 break;
 105                                         ra = stack_register_fetch(sp,
 106                                             ra_stack_pos);
 107                                         if (!ra)
 108                                                 goto done;
 109                                         ra -= 8;
 110                                 }
 111                                 break;
 112                         default:
 113                                 break;
 114                         }
 115                         /* eret */
 116                         if (insn.word == 0x42000018)
 117                                 goto done;
 118                 }
 119
 120                 if (pc == ra && stacksize == 0)
 121                         break;
 122
 123                 sp += stacksize;
 124                 pc = ra;
 125                 ra = 0;
 126         }
 127 done:
 128         return;
 129 }
 130
 131 int
 132 stack_save_td(struct stack *st, struct thread *td)
 133 {
 134         u_register_t pc, sp;
 135
 136         THREAD_LOCK_ASSERT(td, MA_OWNED);
 137         KASSERT(!TD_IS_SWAPPED(td),
 138             ("stack_save_td: thread %p is swapped", td));
 139
 140         if (TD_IS_RUNNING(td))
 141                 return (EOPNOTSUPP);
 142
 143         pc = td->td_pcb->pcb_regs.pc;
 144         sp = td->td_pcb->pcb_regs.sp;
 145         stack_capture(st, pc, sp);
 146         return (0);
 147 }
 148
 149 void
 150 stack_save(struct stack *st)
 151 {
 152         u_register_t pc, sp;
 153
 154         if (curthread == NULL)
 155                 panic("stack_save: curthread == NULL");
 156
 157         pc = curthread->td_pcb->pcb_regs.pc;
 158         sp = curthread->td_pcb->pcb_regs.sp;
 159         stack_capture(st, pc, sp);
 160 }