2 * Copyright (c) 2010 The FreeBSD Foundation
5 * This software was developed by Rui Paulo under sponsorship from the
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
30 #include <sys/cdefs.h>
31 __FBSDID("$FreeBSD$");
33 #include <sys/types.h>
34 #include <sys/ptrace.h>
45 #if defined(__aarch64__)
46 #define AARCH64_BRK 0xd4200000
47 #define AARCH64_BRK_IMM16_SHIFT 5
48 #define AARCH64_BRK_IMM16_VAL (0xd << AARCH64_BRK_IMM16_SHIFT)
49 #define BREAKPOINT_INSTR (AARCH64_BRK | AARCH64_BRK_IMM16_VAL)
50 #define BREAKPOINT_INSTR_SZ 4
51 #elif defined(__amd64__) || defined(__i386__)
52 #define BREAKPOINT_INSTR 0xcc /* int 0x3 */
53 #define BREAKPOINT_INSTR_SZ 1
54 #define BREAKPOINT_ADJUST_SZ BREAKPOINT_INSTR_SZ
55 #elif defined(__arm__)
56 #define BREAKPOINT_INSTR 0xe7ffffff /* bkpt */
57 #define BREAKPOINT_INSTR_SZ 4
58 #elif defined(__mips__)
59 #define BREAKPOINT_INSTR 0xd /* break */
60 #define BREAKPOINT_INSTR_SZ 4
61 #elif defined(__powerpc__)
62 #define BREAKPOINT_INSTR 0x7fe00008 /* trap */
63 #define BREAKPOINT_INSTR_SZ 4
64 #elif defined(__riscv__)
65 #define BREAKPOINT_INSTR 0x00100073 /* sbreak */
66 #define BREAKPOINT_INSTR_SZ 4
68 #error "Add support for your architecture"
72 proc_stop(struct proc_handle *phdl)
76 if (kill(proc_getpid(phdl), SIGSTOP) == -1) {
77 DPRINTF("kill %d", proc_getpid(phdl));
79 } else if (waitpid(proc_getpid(phdl), &status, WSTOPPED) == -1) {
80 DPRINTF("waitpid %d", proc_getpid(phdl));
82 } else if (!WIFSTOPPED(status)) {
83 DPRINTFX("waitpid: unexpected status 0x%x", status);
91 proc_bkptset(struct proc_handle *phdl, uintptr_t address,
94 struct ptrace_io_desc piod;
95 unsigned long paddr, caddr;
99 if (phdl->status == PS_DEAD || phdl->status == PS_UNDEAD ||
100 phdl->status == PS_IDLE) {
105 DPRINTFX("adding breakpoint at 0x%lx", address);
108 if (phdl->status != PS_STOP) {
109 if (proc_stop(phdl) != 0)
115 * Read the original instruction.
119 piod.piod_op = PIOD_READ_I;
120 piod.piod_offs = (void *)caddr;
121 piod.piod_addr = &paddr;
122 piod.piod_len = BREAKPOINT_INSTR_SZ;
123 if (ptrace(PT_IO, proc_getpid(phdl), (caddr_t)&piod, 0) < 0) {
124 DPRINTF("ERROR: couldn't read instruction at address 0x%jx",
131 * Write a breakpoint instruction to that address.
134 paddr = BREAKPOINT_INSTR;
135 piod.piod_op = PIOD_WRITE_I;
136 piod.piod_offs = (void *)caddr;
137 piod.piod_addr = &paddr;
138 piod.piod_len = BREAKPOINT_INSTR_SZ;
139 if (ptrace(PT_IO, proc_getpid(phdl), (caddr_t)&piod, 0) < 0) {
140 DPRINTF("ERROR: couldn't write instruction at address 0x%jx",
148 /* Restart the process if we had to stop it. */
155 proc_bkptdel(struct proc_handle *phdl, uintptr_t address,
158 struct ptrace_io_desc piod;
159 unsigned long paddr, caddr;
160 int ret = 0, stopped;
162 if (phdl->status == PS_DEAD || phdl->status == PS_UNDEAD ||
163 phdl->status == PS_IDLE) {
168 DPRINTFX("removing breakpoint at 0x%lx", address);
171 if (phdl->status != PS_STOP) {
172 if (proc_stop(phdl) != 0)
178 * Overwrite the breakpoint instruction that we setup previously.
182 piod.piod_op = PIOD_WRITE_I;
183 piod.piod_offs = (void *)caddr;
184 piod.piod_addr = &paddr;
185 piod.piod_len = BREAKPOINT_INSTR_SZ;
186 if (ptrace(PT_IO, proc_getpid(phdl), (caddr_t)&piod, 0) < 0) {
187 DPRINTF("ERROR: couldn't write instruction at address 0x%jx",
193 /* Restart the process if we had to stop it. */
200 * Decrement pc so that we delete the breakpoint at the correct
201 * address, i.e. at the BREAKPOINT_INSTR address.
203 * This is only needed on some architectures where the pc value
204 * when reading registers points at the instruction after the
205 * breakpoint, e.g. x86.
208 proc_bkptregadj(unsigned long *pc)
212 #ifdef BREAKPOINT_ADJUST_SZ
213 *pc = *pc - BREAKPOINT_ADJUST_SZ;
218 * Step over the breakpoint.
221 proc_bkptexec(struct proc_handle *phdl, unsigned long saved)
224 unsigned long samesaved;
227 if (proc_regget(phdl, REG_PC, &pc) < 0) {
228 DPRINTFX("ERROR: couldn't get PC register");
231 proc_bkptregadj(&pc);
232 if (proc_bkptdel(phdl, pc, saved) < 0) {
233 DPRINTFX("ERROR: couldn't delete breakpoint");
237 * Go back in time and step over the new instruction just
238 * set up by proc_bkptdel().
240 proc_regset(phdl, REG_PC, pc);
241 if (ptrace(PT_STEP, proc_getpid(phdl), (caddr_t)1, 0) < 0) {
242 DPRINTFX("ERROR: ptrace step failed");
246 status = proc_getwstat(phdl);
247 if (!WIFSTOPPED(status)) {
248 DPRINTFX("ERROR: don't know why process stopped");
252 * Restore the breakpoint. The saved instruction should be
253 * the same as the one that we were passed in.
255 if (proc_bkptset(phdl, pc, &samesaved) < 0) {
256 DPRINTFX("ERROR: couldn't restore breakpoint");
259 assert(samesaved == saved);