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>
36 #include <machine/_inttypes.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
65 #error "Add support for your architecture"
69 proc_stop(struct proc_handle *phdl)
73 if (kill(proc_getpid(phdl), SIGSTOP) == -1) {
74 DPRINTF("kill %d", proc_getpid(phdl));
76 } else if (waitpid(proc_getpid(phdl), &status, WSTOPPED) == -1) {
77 DPRINTF("waitpid %d", proc_getpid(phdl));
79 } else if (!WIFSTOPPED(status)) {
80 DPRINTFX("waitpid: unexpected status 0x%x", status);
88 proc_bkptset(struct proc_handle *phdl, uintptr_t address,
91 struct ptrace_io_desc piod;
92 unsigned long paddr, caddr;
96 if (phdl->status == PS_DEAD || phdl->status == PS_UNDEAD ||
97 phdl->status == PS_IDLE) {
102 DPRINTFX("adding breakpoint at 0x%lx", address);
105 if (phdl->status != PS_STOP) {
106 if (proc_stop(phdl) != 0)
112 * Read the original instruction.
116 piod.piod_op = PIOD_READ_I;
117 piod.piod_offs = (void *)caddr;
118 piod.piod_addr = &paddr;
119 piod.piod_len = BREAKPOINT_INSTR_SZ;
120 if (ptrace(PT_IO, proc_getpid(phdl), (caddr_t)&piod, 0) < 0) {
121 DPRINTF("ERROR: couldn't read instruction at address 0x%"
128 * Write a breakpoint instruction to that address.
131 paddr = BREAKPOINT_INSTR;
132 piod.piod_op = PIOD_WRITE_I;
133 piod.piod_offs = (void *)caddr;
134 piod.piod_addr = &paddr;
135 piod.piod_len = BREAKPOINT_INSTR_SZ;
136 if (ptrace(PT_IO, proc_getpid(phdl), (caddr_t)&piod, 0) < 0) {
137 DPRINTF("ERROR: couldn't write instruction at address 0x%"
145 /* Restart the process if we had to stop it. */
152 proc_bkptdel(struct proc_handle *phdl, uintptr_t address,
155 struct ptrace_io_desc piod;
156 unsigned long paddr, caddr;
157 int ret = 0, stopped;
159 if (phdl->status == PS_DEAD || phdl->status == PS_UNDEAD ||
160 phdl->status == PS_IDLE) {
165 DPRINTFX("removing breakpoint at 0x%lx", address);
168 if (phdl->status != PS_STOP) {
169 if (proc_stop(phdl) != 0)
175 * Overwrite the breakpoint instruction that we setup previously.
179 piod.piod_op = PIOD_WRITE_I;
180 piod.piod_offs = (void *)caddr;
181 piod.piod_addr = &paddr;
182 piod.piod_len = BREAKPOINT_INSTR_SZ;
183 if (ptrace(PT_IO, proc_getpid(phdl), (caddr_t)&piod, 0) < 0) {
184 DPRINTF("ERROR: couldn't write instruction at address 0x%"
190 /* Restart the process if we had to stop it. */
197 * Decrement pc so that we delete the breakpoint at the correct
198 * address, i.e. at the BREAKPOINT_INSTR address.
200 * This is only needed on some architectures where the pc value
201 * when reading registers points at the instruction after the
202 * breakpoint, e.g. x86.
205 proc_bkptregadj(unsigned long *pc)
209 #ifdef BREAKPOINT_ADJUST_SZ
210 *pc = *pc - BREAKPOINT_ADJUST_SZ;
215 * Step over the breakpoint.
218 proc_bkptexec(struct proc_handle *phdl, unsigned long saved)
221 unsigned long samesaved;
224 if (proc_regget(phdl, REG_PC, &pc) < 0) {
225 DPRINTFX("ERROR: couldn't get PC register");
228 proc_bkptregadj(&pc);
229 if (proc_bkptdel(phdl, pc, saved) < 0) {
230 DPRINTFX("ERROR: couldn't delete breakpoint");
234 * Go back in time and step over the new instruction just
235 * set up by proc_bkptdel().
237 proc_regset(phdl, REG_PC, pc);
238 if (ptrace(PT_STEP, proc_getpid(phdl), (caddr_t)1, 0) < 0) {
239 DPRINTFX("ERROR: ptrace step failed");
243 status = proc_getwstat(phdl);
244 if (!WIFSTOPPED(status)) {
245 DPRINTFX("ERROR: don't know why process stopped");
249 * Restore the breakpoint. The saved instruction should be
250 * the same as the one that we were passed in.
252 if (proc_bkptset(phdl, pc, &samesaved) < 0) {
253 DPRINTFX("ERROR: couldn't restore breakpoint");
256 assert(samesaved == saved);