1 /*-
2 * SPDX-License-Identifier: BSD-4-Clause
3 *
4 * Copyright (C) 1996 Wolfgang Solfrank.
5 * Copyright (C) 1996 TooLs GmbH.
6 * All rights reserved.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
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.
16 * 3. All advertising materials mentioning features or use of this software
17 * must display the following acknowledgement:
18 * This product includes software developed by TooLs GmbH.
19 * 4. The name of TooLs GmbH may not be used to endorse or promote products
20 * derived from this software without specific prior written permission.
21 *
22 * THIS SOFTWARE IS PROVIDED BY TOOLS GMBH ``AS IS'' AND ANY EXPRESS OR
23 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
24 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
25 * IN NO EVENT SHALL TOOLS GMBH BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
26 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
27 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
28 * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
29 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
30 * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
31 * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
32 *
33 * $NetBSD: fpu.c,v 1.5 2001/07/22 11:29:46 wiz Exp $
34 */
35
36 #include <sys/cdefs.h>
37 #include <sys/param.h>
38 #include <sys/proc.h>
39 #include <sys/systm.h>
40 #include <sys/limits.h>
41
42 #include <machine/altivec.h>
43 #include <machine/pcb.h>
44 #include <machine/psl.h>
45
46 static void
save_vec_int(struct thread * td)47 save_vec_int(struct thread *td)
48 {
49 int msr;
50 struct pcb *pcb;
51
52 pcb = td->td_pcb;
53
54 /*
55 * Temporarily re-enable the vector unit during the save
56 */
57 msr = mfmsr();
58 mtmsr(msr | PSL_VEC);
59
60 /*
61 * Save the vector registers and VSCR to the PCB
62 */
63 #define STVX(n) __asm ("stvx %1,0,%0" \
64 :: "b"(pcb->pcb_vec.vr[n]), "n"(n));
65 STVX(0); STVX(1); STVX(2); STVX(3);
66 STVX(4); STVX(5); STVX(6); STVX(7);
67 STVX(8); STVX(9); STVX(10); STVX(11);
68 STVX(12); STVX(13); STVX(14); STVX(15);
69 STVX(16); STVX(17); STVX(18); STVX(19);
70 STVX(20); STVX(21); STVX(22); STVX(23);
71 STVX(24); STVX(25); STVX(26); STVX(27);
72 STVX(28); STVX(29); STVX(30); STVX(31);
73 #undef STVX
74
75 __asm __volatile("mfvscr 0; stvewx 0,0,%0" :: "b"(&pcb->pcb_vec.vscr));
76
77 /*
78 * Disable vector unit again
79 */
80 isync();
81 mtmsr(msr);
82
83 }
84
85 void
enable_vec(struct thread * td)86 enable_vec(struct thread *td)
87 {
88 int msr;
89 struct pcb *pcb;
90 struct trapframe *tf;
91
92 pcb = td->td_pcb;
93 tf = trapframe(td);
94
95 /*
96 * Save the thread's Altivec CPU number, and set the CPU's current
97 * vector thread
98 */
99 td->td_pcb->pcb_veccpu = PCPU_GET(cpuid);
100 PCPU_SET(vecthread, td);
101
102 /*
103 * Enable the vector unit for when the thread returns from the
104 * exception. If this is the first time the unit has been used by
105 * the thread, initialise the vector registers and VSCR to 0, and
106 * set the flag to indicate that the vector unit is in use.
107 */
108 pcb->pcb_flags |= PCB_VEC;
109 tf->srr1 |= PSL_VEC;
110 if (!(pcb->pcb_flags & PCB_VECREGS)) {
111 memset(&pcb->pcb_vec, 0, sizeof pcb->pcb_vec);
112 pcb->pcb_flags |= PCB_VECREGS;
113 }
114
115 /*
116 * Temporarily enable the vector unit so the registers
117 * can be restored.
118 */
119 msr = mfmsr();
120 mtmsr(msr | PSL_VEC);
121
122 /*
123 * Restore VSCR by first loading it into a vector and then into VSCR.
124 * (this needs to done before loading the user's vector registers
125 * since we need to use a scratch vector register)
126 */
127 __asm __volatile("vxor 0,0,0; lvewx 0,0,%0; mtvscr 0" \
128 :: "b"(&pcb->pcb_vec.vscr));
129
130 #define LVX(n) __asm ("lvx " #n ",0,%0" \
131 :: "b"(&pcb->pcb_vec.vr[n]));
132 LVX(0); LVX(1); LVX(2); LVX(3);
133 LVX(4); LVX(5); LVX(6); LVX(7);
134 LVX(8); LVX(9); LVX(10); LVX(11);
135 LVX(12); LVX(13); LVX(14); LVX(15);
136 LVX(16); LVX(17); LVX(18); LVX(19);
137 LVX(20); LVX(21); LVX(22); LVX(23);
138 LVX(24); LVX(25); LVX(26); LVX(27);
139 LVX(28); LVX(29); LVX(30); LVX(31);
140 #undef LVX
141
142 isync();
143 mtmsr(msr);
144 }
145
146 void
save_vec(struct thread * td)147 save_vec(struct thread *td)
148 {
149 struct pcb *pcb;
150
151 pcb = td->td_pcb;
152
153 save_vec_int(td);
154
155 /*
156 * Clear the current vec thread and pcb's CPU id
157 * XXX should this be left clear to allow lazy save/restore ?
158 */
159 pcb->pcb_veccpu = INT_MAX;
160 PCPU_SET(vecthread, NULL);
161 }
162
163 /*
164 * Save altivec state without dropping ownership. This will only save state if
165 * the current vector-thread is `td'.
166 */
167 void
save_vec_nodrop(struct thread * td)168 save_vec_nodrop(struct thread *td)
169 {
170
171 if (td == PCPU_GET(vecthread))
172 save_vec_int(td);
173 }
174
175 void
enable_vec_kern(void)176 enable_vec_kern(void)
177 {
178 mtmsr(mfmsr() | PSL_VEC);
179 }
180
181 void
disable_vec(struct thread * td)182 disable_vec(struct thread *td)
183 {
184 register_t msr;
185 struct pcb *pcb;
186 struct trapframe *tf;
187
188 pcb = td->td_pcb;
189 tf = trapframe(td);
190
191 /* Disable PSL_VEC in kernel (if enabled) */
192 msr = mfmsr() & ~PSL_VEC;
193 isync();
194 mtmsr(msr);
195
196 /*
197 * Disable PSL_VEC in userspace. It will be re-enabled when
198 * an Altivec instruction is executed.
199 */
200 tf->srr1 &= ~PSL_VEC;
201 pcb->pcb_flags &= ~PCB_VEC;
202 }
203