xref: /freebsd/sys/amd64/ia32/ia32_reg.c (revision 6ef644f5889afbd0f681b08ed1a2f369524af83e)
1 /*-
2  * SPDX-License-Identifier: BSD-2-Clause
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 
29 #include <sys/cdefs.h>
30 #include <sys/param.h>
31 #include <sys/elf.h>
32 #include <sys/exec.h>
33 #include <sys/fcntl.h>
34 #include <sys/imgact.h>
35 #include <sys/kernel.h>
36 #include <sys/lock.h>
37 #include <sys/malloc.h>
38 #include <sys/mutex.h>
39 #include <sys/mman.h>
40 #include <sys/namei.h>
41 #include <sys/proc.h>
42 #include <sys/procfs.h>
43 #include <sys/reg.h>
44 #include <sys/resourcevar.h>
45 #include <sys/systm.h>
46 #include <sys/signalvar.h>
47 #include <sys/stat.h>
48 #include <sys/sx.h>
49 #include <sys/syscall.h>
50 #include <sys/sysctl.h>
51 #include <sys/sysent.h>
52 #include <sys/vnode.h>
53 
54 #include <vm/vm.h>
55 #include <vm/vm_kern.h>
56 #include <vm/vm_param.h>
57 #include <vm/pmap.h>
58 #include <vm/vm_map.h>
59 #include <vm/vm_object.h>
60 #include <vm/vm_extern.h>
61 
62 #include <compat/freebsd32/freebsd32_util.h>
63 #include <compat/freebsd32/freebsd32_proto.h>
64 #include <machine/fpu.h>
65 #include <machine/psl.h>
66 #include <machine/segments.h>
67 #include <machine/specialreg.h>
68 #include <machine/frame.h>
69 #include <machine/md_var.h>
70 #include <machine/pcb.h>
71 #include <machine/cpufunc.h>
72 
73 int
74 fill_regs32(struct thread *td, struct reg32 *regs)
75 {
76 	struct trapframe *tp;
77 
78 	tp = td->td_frame;
79 	if (tp->tf_flags & TF_HASSEGS) {
80 		regs->r_gs = tp->tf_gs;
81 		regs->r_fs = tp->tf_fs;
82 		regs->r_es = tp->tf_es;
83 		regs->r_ds = tp->tf_ds;
84 	} else {
85 		regs->r_gs = _ugssel;
86 		regs->r_fs = _ufssel;
87 		regs->r_es = _udatasel;
88 		regs->r_ds = _udatasel;
89 	}
90 	regs->r_edi = tp->tf_rdi;
91 	regs->r_esi = tp->tf_rsi;
92 	regs->r_ebp = tp->tf_rbp;
93 	regs->r_ebx = tp->tf_rbx;
94 	regs->r_edx = tp->tf_rdx;
95 	regs->r_ecx = tp->tf_rcx;
96 	regs->r_eax = tp->tf_rax;
97 	regs->r_eip = tp->tf_rip;
98 	regs->r_cs = tp->tf_cs;
99 	regs->r_eflags = tp->tf_rflags;
100 	regs->r_esp = tp->tf_rsp;
101 	regs->r_ss = tp->tf_ss;
102 	regs->r_err = 0;
103 	regs->r_trapno = 0;
104 	return (0);
105 }
106 
107 int
108 set_regs32(struct thread *td, struct reg32 *regs)
109 {
110 	struct trapframe *tp;
111 
112 	tp = td->td_frame;
113 	if (!EFL_SECURE(regs->r_eflags, tp->tf_rflags) || !CS_SECURE(regs->r_cs))
114 		return (EINVAL);
115 	tp->tf_gs = regs->r_gs;
116 	tp->tf_fs = regs->r_fs;
117 	tp->tf_es = regs->r_es;
118 	tp->tf_ds = regs->r_ds;
119 	set_pcb_flags(td->td_pcb, PCB_FULL_IRET);
120 	tp->tf_flags = TF_HASSEGS;
121 	tp->tf_rdi = regs->r_edi;
122 	tp->tf_rsi = regs->r_esi;
123 	tp->tf_rbp = regs->r_ebp;
124 	tp->tf_rbx = regs->r_ebx;
125 	tp->tf_rdx = regs->r_edx;
126 	tp->tf_rcx = regs->r_ecx;
127 	tp->tf_rax = regs->r_eax;
128 	tp->tf_rip = regs->r_eip;
129 	tp->tf_cs = regs->r_cs;
130 	tp->tf_rflags = regs->r_eflags;
131 	tp->tf_rsp = regs->r_esp;
132 	tp->tf_ss = regs->r_ss;
133 	return (0);
134 }
135 
136 int
137 fill_fpregs32(struct thread *td, struct fpreg32 *regs)
138 {
139 	struct savefpu *sv_fpu;
140 	struct save87 *sv_87;
141 	struct env87 *penv_87;
142 	struct envxmm *penv_xmm;
143 	struct fpacc87 *fx_reg;
144 	int i, st;
145 	uint64_t mantissa;
146 	uint16_t tw, exp;
147 	uint8_t ab_tw;
148 
149 	bzero(regs, sizeof(*regs));
150 	sv_87 = (struct save87 *)regs;
151 	penv_87 = &sv_87->sv_env;
152 	fpugetregs(td);
153 	sv_fpu = get_pcb_user_save_td(td);
154 	penv_xmm = &sv_fpu->sv_env;
155 
156 	/* FPU control/status */
157 	penv_87->en_cw = penv_xmm->en_cw;
158 	penv_87->en_sw = penv_xmm->en_sw;
159 
160 	/*
161 	 * XXX for en_fip/fcs/foo/fos, check if the fxsave format
162 	 * uses the old-style layout for 32 bit user apps.  If so,
163 	 * read the ip and operand segment registers from there.
164 	 * For now, use the process's %cs/%ds.
165 	 */
166 	penv_87->en_fip = penv_xmm->en_rip;
167 	penv_87->en_fcs = td->td_frame->tf_cs;
168 	penv_87->en_opcode = penv_xmm->en_opcode;
169 	penv_87->en_foo = penv_xmm->en_rdp;
170 	/* Entry into the kernel always sets TF_HASSEGS */
171 	penv_87->en_fos = td->td_frame->tf_ds;
172 
173 	/*
174 	 * FPU registers and tags.
175 	 * For ST(i), i = fpu_reg - top; we start with fpu_reg=7.
176 	 */
177 	st = 7 - ((penv_xmm->en_sw >> 11) & 7);
178 	ab_tw = penv_xmm->en_tw;
179 	tw = 0;
180 	for (i = 0x80; i != 0; i >>= 1) {
181 		sv_87->sv_ac[st] = sv_fpu->sv_fp[st].fp_acc;
182 		tw <<= 2;
183 		if ((ab_tw & i) != 0) {
184 			/* Non-empty - we need to check ST(i) */
185 			fx_reg = &sv_fpu->sv_fp[st].fp_acc;
186 			/* The first 64 bits contain the mantissa. */
187 			mantissa = *((uint64_t *)fx_reg->fp_bytes);
188 			/*
189 			 * The final 16 bits contain the sign bit and the exponent.
190 			 * Mask the sign bit since it is of no consequence to these
191 			 * tests.
192 			 */
193 			exp = *((uint16_t *)&fx_reg->fp_bytes[8]) & 0x7fff;
194 			if (exp == 0) {
195 				if (mantissa == 0)
196 					tw |= 1; /* Zero */
197 				else
198 					tw |= 2; /* Denormal */
199 			} else if (exp == 0x7fff)
200 				tw |= 2; /* Infinity or NaN */
201 		} else
202 			tw |= 3; /* Empty */
203 		st = (st - 1) & 7;
204 	}
205 	penv_87->en_tw = tw;
206 
207 	return (0);
208 }
209 
210 int
211 set_fpregs32(struct thread *td, struct fpreg32 *regs)
212 {
213 	struct save87 *sv_87 = (struct save87 *)regs;
214 	struct env87 *penv_87 = &sv_87->sv_env;
215 	struct savefpu *sv_fpu = get_pcb_user_save_td(td);
216 	struct envxmm *penv_xmm = &sv_fpu->sv_env;
217 	int i;
218 
219 	/* FPU control/status */
220 	penv_xmm->en_cw = penv_87->en_cw;
221 	penv_xmm->en_sw = penv_87->en_sw;
222 	penv_xmm->en_rip = penv_87->en_fip;
223 	/* penv_87->en_fcs and en_fos ignored, see above */
224 	penv_xmm->en_opcode = penv_87->en_opcode;
225 	penv_xmm->en_rdp = penv_87->en_foo;
226 
227 	/* FPU registers and tags */
228 	penv_xmm->en_tw = 0;
229 	for (i = 0; i < 8; ++i) {
230 		sv_fpu->sv_fp[i].fp_acc = sv_87->sv_ac[i];
231 		if ((penv_87->en_tw & (3 << i * 2)) != (3 << i * 2))
232 			penv_xmm->en_tw |= 1 << i;
233 	}
234 
235 	for (i = 8; i < 16; ++i)
236 		bzero(&sv_fpu->sv_fp[i].fp_acc, sizeof(sv_fpu->sv_fp[i].fp_acc));
237 	fpuuserinited(td);
238 
239 	return (0);
240 }
241 
242 int
243 fill_dbregs32(struct thread *td, struct dbreg32 *regs)
244 {
245 	struct dbreg dr;
246 	int err, i;
247 
248 	err = fill_dbregs(td, &dr);
249 	for (i = 0; i < 8; i++)
250 		regs->dr[i] = dr.dr[i];
251 	return (err);
252 }
253 
254 int
255 set_dbregs32(struct thread *td, struct dbreg32 *regs)
256 {
257 	struct dbreg dr;
258 	int i;
259 
260 	for (i = 0; i < 8; i++)
261 		dr.dr[i] = regs->dr[i];
262 	for (i = 8; i < 16; i++)
263 		dr.dr[i] = 0;
264 	return (set_dbregs(td, &dr));
265 }
266 
267 static bool
268 get_i386_segbases(struct regset *rs, struct thread *td, void *buf,
269     size_t *sizep)
270 {
271 	struct segbasereg32 *reg;
272 	struct pcb *pcb;
273 
274 	if (buf != NULL) {
275 		KASSERT(*sizep == sizeof(*reg), ("%s: invalid size", __func__));
276 		reg = buf;
277 
278 		pcb = td->td_pcb;
279 		if (td == curthread)
280 			update_pcb_bases(pcb);
281 		reg->r_fsbase = pcb->pcb_fsbase;
282 		reg->r_gsbase = pcb->pcb_gsbase;
283 	}
284 	*sizep = sizeof(*reg);
285 	return (true);
286 }
287 
288 static bool
289 set_i386_segbases(struct regset *rs, struct thread *td, void *buf,
290     size_t size)
291 {
292 	struct segbasereg32 *reg;
293 	struct pcb *pcb;
294 
295 	KASSERT(size == sizeof(*reg), ("%s: invalid size", __func__));
296 	reg = buf;
297 
298 	pcb = td->td_pcb;
299 	set_pcb_flags(pcb, PCB_FULL_IRET);
300 	pcb->pcb_fsbase = reg->r_fsbase;
301 	td->td_frame->tf_fs = _ufssel;
302 	pcb->pcb_gsbase = reg->r_gsbase;
303 	td->td_frame->tf_gs = _ugssel;
304 
305 	return (true);
306 }
307 
308 static struct regset regset_i386_segbases = {
309 	.note = NT_X86_SEGBASES,
310 	.size = sizeof(struct segbasereg),
311 	.get = get_i386_segbases,
312 	.set = set_i386_segbases,
313 };
314 ELF32_REGSET(regset_i386_segbases);
315