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__FBSDID("$FreeBSD$");
38
39#include <sys/param.h>
40#include <sys/proc.h>
41#include <sys/systm.h>
42#include <sys/limits.h>
43
44#include <machine/fpu.h>
45#include <machine/pcb.h>
46#include <machine/psl.h>
47
48static void
49save_fpu_int(struct thread *td)
50{
51	register_t msr;
52	struct	pcb *pcb;
53
54	pcb = td->td_pcb;
55
56	/*
57	 * Temporarily re-enable floating-point during the save
58	 */
59	msr = mfmsr();
60	if (pcb->pcb_flags & PCB_VSX)
61		mtmsr(msr | PSL_FP | PSL_VSX);
62	else
63		mtmsr(msr | PSL_FP);
64
65	/*
66	 * Save the floating-point registers and FPSCR to the PCB
67	 */
68	if (pcb->pcb_flags & PCB_VSX) {
69	#define SFP(n)   __asm ("stxvw4x " #n ", 0,%0" \
70			:: "b"(&pcb->pcb_fpu.fpr[n]));
71		SFP(0);		SFP(1);		SFP(2);		SFP(3);
72		SFP(4);		SFP(5);		SFP(6);		SFP(7);
73		SFP(8);		SFP(9);		SFP(10);	SFP(11);
74		SFP(12);	SFP(13);	SFP(14);	SFP(15);
75		SFP(16);	SFP(17);	SFP(18);	SFP(19);
76		SFP(20);	SFP(21);	SFP(22);	SFP(23);
77		SFP(24);	SFP(25);	SFP(26);	SFP(27);
78		SFP(28);	SFP(29);	SFP(30);	SFP(31);
79	#undef SFP
80	} else {
81	#define SFP(n)   __asm ("stfd " #n ", 0(%0)" \
82			:: "b"(&pcb->pcb_fpu.fpr[n].fpr));
83		SFP(0);		SFP(1);		SFP(2);		SFP(3);
84		SFP(4);		SFP(5);		SFP(6);		SFP(7);
85		SFP(8);		SFP(9);		SFP(10);	SFP(11);
86		SFP(12);	SFP(13);	SFP(14);	SFP(15);
87		SFP(16);	SFP(17);	SFP(18);	SFP(19);
88		SFP(20);	SFP(21);	SFP(22);	SFP(23);
89		SFP(24);	SFP(25);	SFP(26);	SFP(27);
90		SFP(28);	SFP(29);	SFP(30);	SFP(31);
91	#undef SFP
92	}
93	__asm __volatile ("mffs 0; stfd 0,0(%0)" :: "b"(&pcb->pcb_fpu.fpscr));
94
95	/*
96	 * Disable floating-point again
97	 */
98	isync();
99	mtmsr(msr);
100}
101
102void
103enable_fpu(struct thread *td)
104{
105	register_t msr;
106	struct	pcb *pcb;
107	struct	trapframe *tf;
108
109	pcb = td->td_pcb;
110	tf = trapframe(td);
111
112	/*
113	 * Save the thread's FPU CPU number, and set the CPU's current
114	 * FPU thread
115	 */
116	td->td_pcb->pcb_fpcpu = PCPU_GET(cpuid);
117	PCPU_SET(fputhread, td);
118
119	/*
120	 * Enable the FPU for when the thread returns from the exception.
121	 * If this is the first time the FPU has been used by the thread,
122	 * initialise the FPU registers and FPSCR to 0, and set the flag
123	 * to indicate that the FPU is in use.
124	 */
125	pcb->pcb_flags |= PCB_FPU;
126	if (pcb->pcb_flags & PCB_VSX)
127		tf->srr1 |= PSL_FP | PSL_VSX;
128	else
129		tf->srr1 |= PSL_FP;
130	if (!(pcb->pcb_flags & PCB_FPREGS)) {
131		memset(&pcb->pcb_fpu, 0, sizeof pcb->pcb_fpu);
132		pcb->pcb_flags |= PCB_FPREGS;
133	}
134
135	/*
136	 * Temporarily enable floating-point so the registers
137	 * can be restored.
138	 */
139	msr = mfmsr();
140	if (pcb->pcb_flags & PCB_VSX)
141		mtmsr(msr | PSL_FP | PSL_VSX);
142	else
143		mtmsr(msr | PSL_FP);
144
145	/*
146	 * Load the floating point registers and FPSCR from the PCB.
147	 * (A value of 0xff for mtfsf specifies that all 8 4-bit fields
148	 * of the saved FPSCR are to be loaded from the FPU reg).
149	 */
150	__asm __volatile ("lfd 0,0(%0); mtfsf 0xff,0"
151			  :: "b"(&pcb->pcb_fpu.fpscr));
152
153	if (pcb->pcb_flags & PCB_VSX) {
154	#define LFP(n)   __asm ("lxvw4x " #n ", 0,%0" \
155			:: "b"(&pcb->pcb_fpu.fpr[n]));
156		LFP(0);		LFP(1);		LFP(2);		LFP(3);
157		LFP(4);		LFP(5);		LFP(6);		LFP(7);
158		LFP(8);		LFP(9);		LFP(10);	LFP(11);
159		LFP(12);	LFP(13);	LFP(14);	LFP(15);
160		LFP(16);	LFP(17);	LFP(18);	LFP(19);
161		LFP(20);	LFP(21);	LFP(22);	LFP(23);
162		LFP(24);	LFP(25);	LFP(26);	LFP(27);
163		LFP(28);	LFP(29);	LFP(30);	LFP(31);
164	#undef LFP
165	} else {
166	#define LFP(n)   __asm ("lfd " #n ", 0(%0)" \
167			:: "b"(&pcb->pcb_fpu.fpr[n].fpr));
168		LFP(0);		LFP(1);		LFP(2);		LFP(3);
169		LFP(4);		LFP(5);		LFP(6);		LFP(7);
170		LFP(8);		LFP(9);		LFP(10);	LFP(11);
171		LFP(12);	LFP(13);	LFP(14);	LFP(15);
172		LFP(16);	LFP(17);	LFP(18);	LFP(19);
173		LFP(20);	LFP(21);	LFP(22);	LFP(23);
174		LFP(24);	LFP(25);	LFP(26);	LFP(27);
175		LFP(28);	LFP(29);	LFP(30);	LFP(31);
176	#undef LFP
177	}
178
179	isync();
180	mtmsr(msr);
181}
182
183void
184save_fpu(struct thread *td)
185{
186	struct	pcb *pcb;
187
188	pcb = td->td_pcb;
189
190	save_fpu_int(td);
191
192	/*
193	 * Clear the current fp thread and pcb's CPU id
194	 * XXX should this be left clear to allow lazy save/restore ?
195	 */
196	pcb->pcb_fpcpu = INT_MAX;
197	PCPU_SET(fputhread, NULL);
198}
199
200/*
201 * Save fpu state without dropping ownership.  This will only save state if
202 * the current fpu thread is `td'.
203 */
204void
205save_fpu_nodrop(struct thread *td)
206{
207
208	if (td == PCPU_GET(fputhread))
209		save_fpu_int(td);
210}
211
212/*
213 * Clear Floating-Point Status and Control Register
214 */
215void
216cleanup_fpscr()
217{
218	register_t msr;
219
220	msr = mfmsr();
221	mtmsr(msr | PSL_FP);
222	mtfsf(0);
223
224	isync();
225	mtmsr(msr);
226}
227
228/*
229 * Get the current fp exception
230 */
231u_int
232get_fpu_exception(struct thread *td)
233{
234	register_t msr;
235	u_int ucode;
236	register_t reg;
237
238	critical_enter();
239
240	msr = mfmsr();
241	mtmsr(msr | PSL_FP);
242
243	reg = mffs();
244
245	isync();
246	mtmsr(msr);
247
248	critical_exit();
249
250	if (reg & FPSCR_ZX)
251		ucode = FPE_FLTDIV;
252	else if (reg & FPSCR_OX)
253		ucode = FPE_FLTOVF;
254	else if (reg & FPSCR_UX)
255		ucode = FPE_FLTUND;
256	else if (reg & FPSCR_XX)
257		ucode = FPE_FLTRES;
258	else
259		ucode = FPE_FLTINV;
260
261	return ucode;
262}
263
264