xref: /freebsd/sys/amd64/ia32/ia32_reg.c (revision 7ec2f6bce5d28e6662c29e63f6ab6b7ef57d98b2)
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/exec.h>
36 #include <sys/fcntl.h>
37 #include <sys/imgact.h>
38 #include <sys/kernel.h>
39 #include <sys/lock.h>
40 #include <sys/malloc.h>
41 #include <sys/mutex.h>
42 #include <sys/mman.h>
43 #include <sys/namei.h>
44 #include <sys/proc.h>
45 #include <sys/procfs.h>
46 #include <sys/resourcevar.h>
47 #include <sys/systm.h>
48 #include <sys/signalvar.h>
49 #include <sys/stat.h>
50 #include <sys/sx.h>
51 #include <sys/syscall.h>
52 #include <sys/sysctl.h>
53 #include <sys/sysent.h>
54 #include <sys/vnode.h>
55 
56 #include <vm/vm.h>
57 #include <vm/vm_kern.h>
58 #include <vm/vm_param.h>
59 #include <vm/pmap.h>
60 #include <vm/vm_map.h>
61 #include <vm/vm_object.h>
62 #include <vm/vm_extern.h>
63 
64 #include <compat/freebsd32/freebsd32_util.h>
65 #include <compat/freebsd32/freebsd32_proto.h>
66 #include <machine/fpu.h>
67 #include <machine/psl.h>
68 #include <machine/segments.h>
69 #include <machine/specialreg.h>
70 #include <machine/frame.h>
71 #include <machine/md_var.h>
72 #include <machine/pcb.h>
73 #include <machine/cpufunc.h>
74 
75 #define	CS_SECURE(cs)		(ISPL(cs) == SEL_UPL)
76 #define	EFL_SECURE(ef, oef)	((((ef) ^ (oef)) & ~PSL_USERCHANGE) == 0)
77 
78 int
79 fill_regs32(struct thread *td, struct reg32 *regs)
80 {
81 	struct trapframe *tp;
82 
83 	tp = td->td_frame;
84 	if (tp->tf_flags & TF_HASSEGS) {
85 		regs->r_gs = tp->tf_gs;
86 		regs->r_fs = tp->tf_fs;
87 		regs->r_es = tp->tf_es;
88 		regs->r_ds = tp->tf_ds;
89 	} else {
90 		regs->r_gs = _ugssel;
91 		regs->r_fs = _ufssel;
92 		regs->r_es = _udatasel;
93 		regs->r_ds = _udatasel;
94 	}
95 	regs->r_edi = tp->tf_rdi;
96 	regs->r_esi = tp->tf_rsi;
97 	regs->r_ebp = tp->tf_rbp;
98 	regs->r_ebx = tp->tf_rbx;
99 	regs->r_edx = tp->tf_rdx;
100 	regs->r_ecx = tp->tf_rcx;
101 	regs->r_eax = tp->tf_rax;
102 	regs->r_eip = tp->tf_rip;
103 	regs->r_cs = tp->tf_cs;
104 	regs->r_eflags = tp->tf_rflags;
105 	regs->r_esp = tp->tf_rsp;
106 	regs->r_ss = tp->tf_ss;
107 	regs->r_err = 0;
108 	regs->r_trapno = 0;
109 	return (0);
110 }
111 
112 int
113 set_regs32(struct thread *td, struct reg32 *regs)
114 {
115 	struct trapframe *tp;
116 
117 	tp = td->td_frame;
118 	if (!EFL_SECURE(regs->r_eflags, tp->tf_rflags) || !CS_SECURE(regs->r_cs))
119 		return (EINVAL);
120 	tp->tf_gs = regs->r_gs;
121 	tp->tf_fs = regs->r_fs;
122 	tp->tf_es = regs->r_es;
123 	tp->tf_ds = regs->r_ds;
124 	set_pcb_flags(td->td_pcb, PCB_FULL_IRET);
125 	tp->tf_flags = TF_HASSEGS;
126 	tp->tf_rdi = regs->r_edi;
127 	tp->tf_rsi = regs->r_esi;
128 	tp->tf_rbp = regs->r_ebp;
129 	tp->tf_rbx = regs->r_ebx;
130 	tp->tf_rdx = regs->r_edx;
131 	tp->tf_rcx = regs->r_ecx;
132 	tp->tf_rax = regs->r_eax;
133 	tp->tf_rip = regs->r_eip;
134 	tp->tf_cs = regs->r_cs;
135 	tp->tf_rflags = regs->r_eflags;
136 	tp->tf_rsp = regs->r_esp;
137 	tp->tf_ss = regs->r_ss;
138 	return (0);
139 }
140 
141 int
142 fill_fpregs32(struct thread *td, struct fpreg32 *regs)
143 {
144 	struct savefpu *sv_fpu;
145 	struct save87 *sv_87;
146 	struct env87 *penv_87;
147 	struct envxmm *penv_xmm;
148 	struct fpacc87 *fx_reg;
149 	int i, st;
150 	uint64_t mantissa;
151 	uint16_t tw, exp;
152 	uint8_t ab_tw;
153 
154 	bzero(regs, sizeof(*regs));
155 	sv_87 = (struct save87 *)regs;
156 	penv_87 = &sv_87->sv_env;
157 	fpugetregs(td);
158 	sv_fpu = get_pcb_user_save_td(td);
159 	penv_xmm = &sv_fpu->sv_env;
160 
161 	/* FPU control/status */
162 	penv_87->en_cw = penv_xmm->en_cw;
163 	penv_87->en_sw = penv_xmm->en_sw;
164 
165 	/*
166 	 * XXX for en_fip/fcs/foo/fos, check if the fxsave format
167 	 * uses the old-style layout for 32 bit user apps.  If so,
168 	 * read the ip and operand segment registers from there.
169 	 * For now, use the process's %cs/%ds.
170 	 */
171 	penv_87->en_fip = penv_xmm->en_rip;
172 	penv_87->en_fcs = td->td_frame->tf_cs;
173 	penv_87->en_opcode = penv_xmm->en_opcode;
174 	penv_87->en_foo = penv_xmm->en_rdp;
175 	/* Entry into the kernel always sets TF_HASSEGS */
176 	penv_87->en_fos = td->td_frame->tf_ds;
177 
178 	/*
179 	 * FPU registers and tags.
180 	 * For ST(i), i = fpu_reg - top; we start with fpu_reg=7.
181 	 */
182 	st = 7 - ((penv_xmm->en_sw >> 11) & 7);
183 	ab_tw = penv_xmm->en_tw;
184 	tw = 0;
185 	for (i = 0x80; i != 0; i >>= 1) {
186 		sv_87->sv_ac[st] = sv_fpu->sv_fp[st].fp_acc;
187 		tw <<= 2;
188 		if ((ab_tw & i) != 0) {
189 			/* Non-empty - we need to check ST(i) */
190 			fx_reg = &sv_fpu->sv_fp[st].fp_acc;
191 			/* The first 64 bits contain the mantissa. */
192 			mantissa = *((uint64_t *)fx_reg->fp_bytes);
193 			/*
194 			 * The final 16 bits contain the sign bit and the exponent.
195 			 * Mask the sign bit since it is of no consequence to these
196 			 * tests.
197 			 */
198 			exp = *((uint16_t *)&fx_reg->fp_bytes[8]) & 0x7fff;
199 			if (exp == 0) {
200 				if (mantissa == 0)
201 					tw |= 1; /* Zero */
202 				else
203 					tw |= 2; /* Denormal */
204 			} else if (exp == 0x7fff)
205 				tw |= 2; /* Infinity or NaN */
206 		} else
207 			tw |= 3; /* Empty */
208 		st = (st - 1) & 7;
209 	}
210 	penv_87->en_tw = tw;
211 
212 	return (0);
213 }
214 
215 int
216 set_fpregs32(struct thread *td, struct fpreg32 *regs)
217 {
218 	struct save87 *sv_87 = (struct save87 *)regs;
219 	struct env87 *penv_87 = &sv_87->sv_env;
220 	struct savefpu *sv_fpu = get_pcb_user_save_td(td);
221 	struct envxmm *penv_xmm = &sv_fpu->sv_env;
222 	int i;
223 
224 	/* FPU control/status */
225 	penv_xmm->en_cw = penv_87->en_cw;
226 	penv_xmm->en_sw = penv_87->en_sw;
227 	penv_xmm->en_rip = penv_87->en_fip;
228 	/* penv_87->en_fcs and en_fos ignored, see above */
229 	penv_xmm->en_opcode = penv_87->en_opcode;
230 	penv_xmm->en_rdp = penv_87->en_foo;
231 
232 	/* FPU registers and tags */
233 	penv_xmm->en_tw = 0;
234 	for (i = 0; i < 8; ++i) {
235 		sv_fpu->sv_fp[i].fp_acc = sv_87->sv_ac[i];
236 		if ((penv_87->en_tw & (3 << i * 2)) != (3 << i * 2))
237 			penv_xmm->en_tw |= 1 << i;
238 	}
239 
240 	for (i = 8; i < 16; ++i)
241 		bzero(&sv_fpu->sv_fp[i].fp_acc, sizeof(sv_fpu->sv_fp[i].fp_acc));
242 	fpuuserinited(td);
243 
244 	return (0);
245 }
246 
247 int
248 fill_dbregs32(struct thread *td, struct dbreg32 *regs)
249 {
250 	struct dbreg dr;
251 	int err, i;
252 
253 	err = fill_dbregs(td, &dr);
254 	for (i = 0; i < 8; i++)
255 		regs->dr[i] = dr.dr[i];
256 	return (err);
257 }
258 
259 int
260 set_dbregs32(struct thread *td, struct dbreg32 *regs)
261 {
262 	struct dbreg dr;
263 	int i;
264 
265 	for (i = 0; i < 8; i++)
266 		dr.dr[i] = regs->dr[i];
267 	for (i = 8; i < 16; i++)
268 		dr.dr[i] = 0;
269 	return (set_dbregs(td, &dr));
270 }
271