xref: /freebsd/sys/i386/i386/ptrace_machdep.c (revision 069ac184)
1 /*-
2  * SPDX-License-Identifier: BSD-2-Clause
3  *
4  * Copyright (c) 2005 Doug Rabson
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 
30 #include <sys/cdefs.h>
31 #include "opt_cpu.h"
32 
33 #include <sys/param.h>
34 #include <sys/systm.h>
35 #include <sys/elf.h>
36 #include <sys/lock.h>
37 #include <sys/malloc.h>
38 #include <sys/mutex.h>
39 #include <sys/proc.h>
40 #include <sys/ptrace.h>
41 #include <sys/reg.h>
42 #include <machine/frame.h>
43 #include <machine/md_var.h>
44 #include <machine/pcb.h>
45 
46 static uint32_t
47 get_segbase(struct segment_descriptor *sdp)
48 {
49 	return (sdp->sd_hibase << 24 | sdp->sd_lobase);
50 }
51 
52 static bool
53 get_segbases(struct regset *rs, struct thread *td, void *buf,
54     size_t *sizep)
55 {
56 	struct segbasereg *reg;
57 
58 	if (buf != NULL) {
59 		KASSERT(*sizep == sizeof(*reg), ("%s: invalid size", __func__));
60 		reg = buf;
61 		reg->r_fsbase = get_segbase(&td->td_pcb->pcb_fsd);
62 		reg->r_gsbase = get_segbase(&td->td_pcb->pcb_gsd);
63 	}
64 	*sizep = sizeof(*reg);
65 	return (true);
66 }
67 
68 static bool
69 set_segbases(struct regset *rs, struct thread *td, void *buf,
70     size_t size)
71 {
72 	struct segbasereg *reg;
73 
74 	KASSERT(size == sizeof(*reg), ("%s: invalid size", __func__));
75 	reg = buf;
76 
77 	fill_based_sd(&td->td_pcb->pcb_fsd, reg->r_fsbase);
78 	td->td_frame->tf_fs = GSEL(GUFS_SEL, SEL_UPL);
79 	fill_based_sd(&td->td_pcb->pcb_gsd, reg->r_gsbase);
80 	td->td_pcb->pcb_gs = GSEL(GUGS_SEL, SEL_UPL);
81 
82 	return (true);
83 }
84 
85 static struct regset regset_segbases = {
86 	.note = NT_X86_SEGBASES,
87 	.size = sizeof(struct segbasereg),
88 	.get = get_segbases,
89 	.set = set_segbases,
90 };
91 ELF_REGSET(regset_segbases);
92 
93 static int
94 cpu_ptrace_xstate(struct thread *td, int req, void *addr, int data)
95 {
96 	struct ptrace_xstate_info info;
97 	char *savefpu;
98 	int error;
99 
100 	if (!use_xsave)
101 		return (EOPNOTSUPP);
102 
103 	switch (req) {
104 	case PT_GETXSTATE_OLD:
105 		npxgetregs(td);
106 		savefpu = (char *)(get_pcb_user_save_td(td) + 1);
107 		error = copyout(savefpu, addr,
108 		    cpu_max_ext_state_size - sizeof(union savefpu));
109 		break;
110 
111 	case PT_SETXSTATE_OLD:
112 		if (data > cpu_max_ext_state_size - sizeof(union savefpu)) {
113 			error = EINVAL;
114 			break;
115 		}
116 		savefpu = malloc(data, M_TEMP, M_WAITOK);
117 		error = copyin(addr, savefpu, data);
118 		if (error == 0) {
119 			npxgetregs(td);
120 			error = npxsetxstate(td, savefpu, data);
121 		}
122 		free(savefpu, M_TEMP);
123 		break;
124 
125 	case PT_GETXSTATE_INFO:
126 		if (data != sizeof(info)) {
127 			error  = EINVAL;
128 			break;
129 		}
130 		info.xsave_len = cpu_max_ext_state_size;
131 		info.xsave_mask = xsave_mask;
132 		error = copyout(&info, addr, data);
133 		break;
134 
135 	case PT_GETXSTATE:
136 		npxgetregs(td);
137 		savefpu = (char *)(get_pcb_user_save_td(td));
138 		error = copyout(savefpu, addr, cpu_max_ext_state_size);
139 		break;
140 
141 	case PT_SETXSTATE:
142 		if (data < sizeof(union savefpu) ||
143 		    data > cpu_max_ext_state_size) {
144 			error = EINVAL;
145 			break;
146 		}
147 		savefpu = malloc(data, M_TEMP, M_WAITOK);
148 		error = copyin(addr, savefpu, data);
149 		if (error == 0)
150 			error = npxsetregs(td, (union savefpu *)savefpu,
151 			    savefpu + sizeof(union savefpu), data -
152 			    sizeof(union savefpu));
153 		free(savefpu, M_TEMP);
154 		break;
155 
156 	default:
157 		error = EINVAL;
158 		break;
159 	}
160 
161 	return (error);
162 }
163 
164 static int
165 cpu_ptrace_xmm(struct thread *td, int req, void *addr, int data)
166 {
167 	struct savexmm *fpstate;
168 	int error;
169 
170 	if (!cpu_fxsr)
171 		return (EINVAL);
172 
173 	fpstate = &get_pcb_user_save_td(td)->sv_xmm;
174 	switch (req) {
175 	case PT_GETXMMREGS:
176 		npxgetregs(td);
177 		error = copyout(fpstate, addr, sizeof(*fpstate));
178 		break;
179 
180 	case PT_SETXMMREGS:
181 		npxgetregs(td);
182 		error = copyin(addr, fpstate, sizeof(*fpstate));
183 		fpstate->sv_env.en_mxcsr &= cpu_mxcsr_mask;
184 		break;
185 
186 	case PT_GETXSTATE_OLD:
187 	case PT_SETXSTATE_OLD:
188 	case PT_GETXSTATE_INFO:
189 	case PT_GETXSTATE:
190 	case PT_SETXSTATE:
191 		error = cpu_ptrace_xstate(td, req, addr, data);
192 		break;
193 
194 	default:
195 		return (EINVAL);
196 	}
197 
198 	return (error);
199 }
200 
201 int
202 cpu_ptrace(struct thread *td, int req, void *addr, int data)
203 {
204 	struct segment_descriptor *sdp, sd;
205 	register_t r;
206 	int error;
207 
208 	switch (req) {
209 	case PT_GETXMMREGS:
210 	case PT_SETXMMREGS:
211 	case PT_GETXSTATE_OLD:
212 	case PT_SETXSTATE_OLD:
213 	case PT_GETXSTATE_INFO:
214 	case PT_GETXSTATE:
215 	case PT_SETXSTATE:
216 		error = cpu_ptrace_xmm(td, req, addr, data);
217 		break;
218 
219 	case PT_GETFSBASE:
220 	case PT_GETGSBASE:
221 		sdp = req == PT_GETFSBASE ? &td->td_pcb->pcb_fsd :
222 		    &td->td_pcb->pcb_gsd;
223 		r = get_segbase(sdp);
224 		error = copyout(&r, addr, sizeof(r));
225 		break;
226 
227 	case PT_SETFSBASE:
228 	case PT_SETGSBASE:
229 		error = copyin(addr, &r, sizeof(r));
230 		if (error != 0)
231 			break;
232 		fill_based_sd(&sd, r);
233 		if (req == PT_SETFSBASE) {
234 			td->td_pcb->pcb_fsd = sd;
235 			td->td_frame->tf_fs = GSEL(GUFS_SEL, SEL_UPL);
236 		} else {
237 			td->td_pcb->pcb_gsd = sd;
238 			td->td_pcb->pcb_gs = GSEL(GUGS_SEL, SEL_UPL);
239 		}
240 		break;
241 
242 	default:
243 		return (EINVAL);
244 	}
245 
246 	return (error);
247 }
248 
249 int
250 ptrace_set_pc(struct thread *td, u_long addr)
251 {
252 
253 	td->td_frame->tf_eip = addr;
254 	return (0);
255 }
256 
257 int
258 ptrace_single_step(struct thread *td)
259 {
260 
261 	PROC_LOCK_ASSERT(td->td_proc, MA_OWNED);
262 	if ((td->td_frame->tf_eflags & PSL_T) == 0) {
263 		td->td_frame->tf_eflags |= PSL_T;
264 		td->td_dbgflags |= TDB_STEP;
265 	}
266 	return (0);
267 }
268 
269 int
270 ptrace_clear_single_step(struct thread *td)
271 {
272 
273 	PROC_LOCK_ASSERT(td->td_proc, MA_OWNED);
274 	td->td_frame->tf_eflags &= ~PSL_T;
275 	td->td_dbgflags &= ~TDB_STEP;
276 	return (0);
277 }
278