xref: /freebsd/sys/amd64/ia32/ia32_reg.c (revision b9e5884ef786a6c0fd203064baa07ef308025707)
1 /*-
2  * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
3  *
4  * Copyright (c) 2005 Peter Wemm
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  * $FreeBSD$
29  */
30 
31 #include <sys/cdefs.h>
32 __FBSDID("$FreeBSD$");
33 
34 #include <sys/param.h>
35 #include <sys/elf.h>
36 #include <sys/exec.h>
37 #include <sys/fcntl.h>
38 #include <sys/imgact.h>
39 #include <sys/kernel.h>
40 #include <sys/lock.h>
41 #include <sys/malloc.h>
42 #include <sys/mutex.h>
43 #include <sys/mman.h>
44 #include <sys/namei.h>
45 #include <sys/proc.h>
46 #include <sys/procfs.h>
47 #include <sys/reg.h>
48 #include <sys/resourcevar.h>
49 #include <sys/systm.h>
50 #include <sys/signalvar.h>
51 #include <sys/stat.h>
52 #include <sys/sx.h>
53 #include <sys/syscall.h>
54 #include <sys/sysctl.h>
55 #include <sys/sysent.h>
56 #include <sys/vnode.h>
57 
58 #include <vm/vm.h>
59 #include <vm/vm_kern.h>
60 #include <vm/vm_param.h>
61 #include <vm/pmap.h>
62 #include <vm/vm_map.h>
63 #include <vm/vm_object.h>
64 #include <vm/vm_extern.h>
65 
66 #include <compat/freebsd32/freebsd32_util.h>
67 #include <compat/freebsd32/freebsd32_proto.h>
68 #include <machine/fpu.h>
69 #include <machine/psl.h>
70 #include <machine/segments.h>
71 #include <machine/specialreg.h>
72 #include <machine/frame.h>
73 #include <machine/md_var.h>
74 #include <machine/pcb.h>
75 #include <machine/cpufunc.h>
76 
77 int
78 fill_regs32(struct thread *td, struct reg32 *regs)
79 {
80 	struct trapframe *tp;
81 
82 	tp = td->td_frame;
83 	if (tp->tf_flags & TF_HASSEGS) {
84 		regs->r_gs = tp->tf_gs;
85 		regs->r_fs = tp->tf_fs;
86 		regs->r_es = tp->tf_es;
87 		regs->r_ds = tp->tf_ds;
88 	} else {
89 		regs->r_gs = _ugssel;
90 		regs->r_fs = _ufssel;
91 		regs->r_es = _udatasel;
92 		regs->r_ds = _udatasel;
93 	}
94 	regs->r_edi = tp->tf_rdi;
95 	regs->r_esi = tp->tf_rsi;
96 	regs->r_ebp = tp->tf_rbp;
97 	regs->r_ebx = tp->tf_rbx;
98 	regs->r_edx = tp->tf_rdx;
99 	regs->r_ecx = tp->tf_rcx;
100 	regs->r_eax = tp->tf_rax;
101 	regs->r_eip = tp->tf_rip;
102 	regs->r_cs = tp->tf_cs;
103 	regs->r_eflags = tp->tf_rflags;
104 	regs->r_esp = tp->tf_rsp;
105 	regs->r_ss = tp->tf_ss;
106 	regs->r_err = 0;
107 	regs->r_trapno = 0;
108 	return (0);
109 }
110 
111 int
112 set_regs32(struct thread *td, struct reg32 *regs)
113 {
114 	struct trapframe *tp;
115 
116 	tp = td->td_frame;
117 	if (!EFL_SECURE(regs->r_eflags, tp->tf_rflags) || !CS_SECURE(regs->r_cs))
118 		return (EINVAL);
119 	tp->tf_gs = regs->r_gs;
120 	tp->tf_fs = regs->r_fs;
121 	tp->tf_es = regs->r_es;
122 	tp->tf_ds = regs->r_ds;
123 	set_pcb_flags(td->td_pcb, PCB_FULL_IRET);
124 	tp->tf_flags = TF_HASSEGS;
125 	tp->tf_rdi = regs->r_edi;
126 	tp->tf_rsi = regs->r_esi;
127 	tp->tf_rbp = regs->r_ebp;
128 	tp->tf_rbx = regs->r_ebx;
129 	tp->tf_rdx = regs->r_edx;
130 	tp->tf_rcx = regs->r_ecx;
131 	tp->tf_rax = regs->r_eax;
132 	tp->tf_rip = regs->r_eip;
133 	tp->tf_cs = regs->r_cs;
134 	tp->tf_rflags = regs->r_eflags;
135 	tp->tf_rsp = regs->r_esp;
136 	tp->tf_ss = regs->r_ss;
137 	return (0);
138 }
139 
140 int
141 fill_fpregs32(struct thread *td, struct fpreg32 *regs)
142 {
143 	struct savefpu *sv_fpu;
144 	struct save87 *sv_87;
145 	struct env87 *penv_87;
146 	struct envxmm *penv_xmm;
147 	struct fpacc87 *fx_reg;
148 	int i, st;
149 	uint64_t mantissa;
150 	uint16_t tw, exp;
151 	uint8_t ab_tw;
152 
153 	bzero(regs, sizeof(*regs));
154 	sv_87 = (struct save87 *)regs;
155 	penv_87 = &sv_87->sv_env;
156 	fpugetregs(td);
157 	sv_fpu = get_pcb_user_save_td(td);
158 	penv_xmm = &sv_fpu->sv_env;
159 
160 	/* FPU control/status */
161 	penv_87->en_cw = penv_xmm->en_cw;
162 	penv_87->en_sw = penv_xmm->en_sw;
163 
164 	/*
165 	 * XXX for en_fip/fcs/foo/fos, check if the fxsave format
166 	 * uses the old-style layout for 32 bit user apps.  If so,
167 	 * read the ip and operand segment registers from there.
168 	 * For now, use the process's %cs/%ds.
169 	 */
170 	penv_87->en_fip = penv_xmm->en_rip;
171 	penv_87->en_fcs = td->td_frame->tf_cs;
172 	penv_87->en_opcode = penv_xmm->en_opcode;
173 	penv_87->en_foo = penv_xmm->en_rdp;
174 	/* Entry into the kernel always sets TF_HASSEGS */
175 	penv_87->en_fos = td->td_frame->tf_ds;
176 
177 	/*
178 	 * FPU registers and tags.
179 	 * For ST(i), i = fpu_reg - top; we start with fpu_reg=7.
180 	 */
181 	st = 7 - ((penv_xmm->en_sw >> 11) & 7);
182 	ab_tw = penv_xmm->en_tw;
183 	tw = 0;
184 	for (i = 0x80; i != 0; i >>= 1) {
185 		sv_87->sv_ac[st] = sv_fpu->sv_fp[st].fp_acc;
186 		tw <<= 2;
187 		if ((ab_tw & i) != 0) {
188 			/* Non-empty - we need to check ST(i) */
189 			fx_reg = &sv_fpu->sv_fp[st].fp_acc;
190 			/* The first 64 bits contain the mantissa. */
191 			mantissa = *((uint64_t *)fx_reg->fp_bytes);
192 			/*
193 			 * The final 16 bits contain the sign bit and the exponent.
194 			 * Mask the sign bit since it is of no consequence to these
195 			 * tests.
196 			 */
197 			exp = *((uint16_t *)&fx_reg->fp_bytes[8]) & 0x7fff;
198 			if (exp == 0) {
199 				if (mantissa == 0)
200 					tw |= 1; /* Zero */
201 				else
202 					tw |= 2; /* Denormal */
203 			} else if (exp == 0x7fff)
204 				tw |= 2; /* Infinity or NaN */
205 		} else
206 			tw |= 3; /* Empty */
207 		st = (st - 1) & 7;
208 	}
209 	penv_87->en_tw = tw;
210 
211 	return (0);
212 }
213 
214 int
215 set_fpregs32(struct thread *td, struct fpreg32 *regs)
216 {
217 	struct save87 *sv_87 = (struct save87 *)regs;
218 	struct env87 *penv_87 = &sv_87->sv_env;
219 	struct savefpu *sv_fpu = get_pcb_user_save_td(td);
220 	struct envxmm *penv_xmm = &sv_fpu->sv_env;
221 	int i;
222 
223 	/* FPU control/status */
224 	penv_xmm->en_cw = penv_87->en_cw;
225 	penv_xmm->en_sw = penv_87->en_sw;
226 	penv_xmm->en_rip = penv_87->en_fip;
227 	/* penv_87->en_fcs and en_fos ignored, see above */
228 	penv_xmm->en_opcode = penv_87->en_opcode;
229 	penv_xmm->en_rdp = penv_87->en_foo;
230 
231 	/* FPU registers and tags */
232 	penv_xmm->en_tw = 0;
233 	for (i = 0; i < 8; ++i) {
234 		sv_fpu->sv_fp[i].fp_acc = sv_87->sv_ac[i];
235 		if ((penv_87->en_tw & (3 << i * 2)) != (3 << i * 2))
236 			penv_xmm->en_tw |= 1 << i;
237 	}
238 
239 	for (i = 8; i < 16; ++i)
240 		bzero(&sv_fpu->sv_fp[i].fp_acc, sizeof(sv_fpu->sv_fp[i].fp_acc));
241 	fpuuserinited(td);
242 
243 	return (0);
244 }
245 
246 int
247 fill_dbregs32(struct thread *td, struct dbreg32 *regs)
248 {
249 	struct dbreg dr;
250 	int err, i;
251 
252 	err = fill_dbregs(td, &dr);
253 	for (i = 0; i < 8; i++)
254 		regs->dr[i] = dr.dr[i];
255 	return (err);
256 }
257 
258 int
259 set_dbregs32(struct thread *td, struct dbreg32 *regs)
260 {
261 	struct dbreg dr;
262 	int i;
263 
264 	for (i = 0; i < 8; i++)
265 		dr.dr[i] = regs->dr[i];
266 	for (i = 8; i < 16; i++)
267 		dr.dr[i] = 0;
268 	return (set_dbregs(td, &dr));
269 }
270 
271 static bool
272 get_i386_segbases(struct regset *rs, struct thread *td, void *buf,
273     size_t *sizep)
274 {
275 	struct segbasereg32 *reg;
276 	struct pcb *pcb;
277 
278 	if (buf != NULL) {
279 		KASSERT(*sizep == sizeof(*reg), ("%s: invalid size", __func__));
280 		reg = buf;
281 
282 		pcb = td->td_pcb;
283 		if (td == curthread)
284 			update_pcb_bases(pcb);
285 		reg->r_fsbase = pcb->pcb_fsbase;
286 		reg->r_gsbase = pcb->pcb_gsbase;
287 	}
288 	*sizep = sizeof(*reg);
289 	return (true);
290 }
291 
292 static bool
293 set_i386_segbases(struct regset *rs, struct thread *td, void *buf,
294     size_t size)
295 {
296 	struct segbasereg32 *reg;
297 	struct pcb *pcb;
298 
299 	KASSERT(size == sizeof(*reg), ("%s: invalid size", __func__));
300 	reg = buf;
301 
302 	pcb = td->td_pcb;
303 	set_pcb_flags(pcb, PCB_FULL_IRET);
304 	pcb->pcb_fsbase = reg->r_fsbase;
305 	td->td_frame->tf_fs = _ufssel;
306 	pcb->pcb_gsbase = reg->r_gsbase;
307 	td->td_frame->tf_gs = _ugssel;
308 
309 	return (true);
310 }
311 
312 static struct regset regset_i386_segbases = {
313 	.note = NT_X86_SEGBASES,
314 	.size = sizeof(struct segbasereg),
315 	.get = get_i386_segbases,
316 	.set = set_i386_segbases,
317 };
318 ELF32_REGSET(regset_i386_segbases);
319