stack_machdep.c revision 331722 
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: stable/11/sys/mips/mips/stack_machdep.c 331722 2018-03-29 02:50:57Z eadler $");
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/pcb.h>
39#include <machine/regnum.h>
40
41static u_register_t
42stack_register_fetch(u_register_t sp, u_register_t stack_pos)
43{
44	u_register_t * stack =
45	    ((u_register_t *)(intptr_t)sp + (size_t)stack_pos/sizeof(u_register_t));
46
47	return *stack;
48}
49
50static void
51stack_capture(struct stack *st, u_register_t pc, u_register_t sp)
52{
53	u_register_t  ra = 0, i, stacksize;
54	short ra_stack_pos = 0;
55	InstFmt insn;
56
57	stack_zero(st);
58
59	for (;;) {
60		stacksize = 0;
61		if (pc <= (u_register_t)(intptr_t)btext)
62			break;
63		for (i = pc; i >= (u_register_t)(intptr_t)btext; i -= sizeof (insn)) {
64			bcopy((void *)(intptr_t)i, &insn, sizeof insn);
65			switch (insn.IType.op) {
66			case OP_ADDI:
67			case OP_ADDIU:
68			case OP_DADDI:
69			case OP_DADDIU:
70				if (insn.IType.rs != SP || insn.IType.rt != SP)
71					break;
72				stacksize = -(short)insn.IType.imm;
73				break;
74
75			case OP_SW:
76			case OP_SD:
77				if (insn.IType.rs != SP || insn.IType.rt != RA)
78					break;
79				ra_stack_pos = (short)insn.IType.imm;
80				break;
81			default:
82				break;
83			}
84
85			if (stacksize)
86				break;
87		}
88
89		if (stack_put(st, pc) == -1)
90			break;
91
92		for (i = pc; !ra; i += sizeof (insn)) {
93			bcopy((void *)(intptr_t)i, &insn, sizeof insn);
94
95			switch (insn.IType.op) {
96			case OP_SPECIAL:
97				if((insn.RType.func == OP_JR))
98				{
99					if (ra >= (u_register_t)(intptr_t)btext)
100						break;
101					if (insn.RType.rs != RA)
102						break;
103					ra = stack_register_fetch(sp,
104					    ra_stack_pos);
105					if (!ra)
106						goto done;
107					ra -= 8;
108				}
109				break;
110			default:
111				break;
112			}
113			/* eret */
114			if (insn.word == 0x42000018)
115				goto done;
116		}
117
118		if (pc == ra && stacksize == 0)
119			break;
120
121		sp += stacksize;
122		pc = ra;
123		ra = 0;
124	}
125done:
126	return;
127}
128
129void
130stack_save_td(struct stack *st, struct thread *td)
131{
132	u_register_t pc, sp;
133
134	if (TD_IS_SWAPPED(td))
135		panic("stack_save_td: swapped");
136	if (TD_IS_RUNNING(td))
137		panic("stack_save_td: running");
138
139	pc = td->td_pcb->pcb_regs.pc;
140	sp = td->td_pcb->pcb_regs.sp;
141	stack_capture(st, pc, sp);
142}
143
144int
145stack_save_td_running(struct stack *st, struct thread *td)
146{
147
148	return (EOPNOTSUPP);
149}
150
151void
152stack_save(struct stack *st)
153{
154	u_register_t pc, sp;
155
156	if (curthread == NULL)
157		panic("stack_save: curthread == NULL");
158
159	pc = curthread->td_pcb->pcb_regs.pc;
160	sp = curthread->td_pcb->pcb_regs.sp;
161	stack_capture(st, pc, sp);
162}
163