xref: /illumos-gate/usr/src/uts/intel/sys/fp.h (revision dd72704bd9e794056c558153663c739e2012d721)
1 /*
2  * CDDL HEADER START
3  *
4  * The contents of this file are subject to the terms of the
5  * Common Development and Distribution License (the "License").
6  * You may not use this file except in compliance with the License.
7  *
8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9  * or http://www.opensolaris.org/os/licensing.
10  * See the License for the specific language governing permissions
11  * and limitations under the License.
12  *
13  * When distributing Covered Code, include this CDDL HEADER in each
14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15  * If applicable, add the following below this CDDL HEADER, with the
16  * fields enclosed by brackets "[]" replaced with your own identifying
17  * information: Portions Copyright [yyyy] [name of copyright owner]
18  *
19  * CDDL HEADER END
20  */
21 /*
22  * Copyright 2015 Nexenta Systems, Inc.  All rights reserved.
23  * Copyright (c) 2018, Joyent, Inc.
24  * Copyright 2022 Oxide Computer Company
25  *
26  * Copyright (c) 1992, 2010, Oracle and/or its affiliates. All rights reserved.
27  */
28 
29 /*	Copyright (c) 1990, 1991 UNIX System Laboratories, Inc.	*/
30 /*	Copyright (c) 1984, 1986, 1987, 1988, 1989, 1990 AT&T	*/
31 /*		All Rights Reserved				*/
32 
33 #ifndef _SYS_FP_H
34 #define	_SYS_FP_H
35 
36 #ifdef __cplusplus
37 extern "C" {
38 #endif
39 
40 /*
41  * 80287/80387 and SSE/SSE2 floating point processor definitions
42  */
43 
44 /*
45  * values that go into fp_kind
46  */
47 #define	FP_NO	0	/* no fp chip, no emulator (no fp support)	*/
48 #define	FP_SW	1	/* no fp chip, using software emulator		*/
49 #define	FP_HW	2	/* chip present bit				*/
50 #define	FP_287	2	/* 80287 chip present				*/
51 #define	FP_387	3	/* 80387 chip present				*/
52 #define	FP_487	6	/* 80487 chip present				*/
53 #define	FP_486	6	/* 80486 chip present				*/
54 /*
55  * The following values are bit flags instead of actual values.
56  * E.g. to know if we are using SSE, test (value & __FP_SSE) instead
57  * of (value == __FP_SSE).
58  */
59 #define	__FP_SSE	0x100	/* .. plus SSE-capable CPU		*/
60 #define	__FP_AVX	0x200	/* .. plus AVX-capable CPU		*/
61 
62 /*
63  * values that go into fp_save_mech
64  */
65 #define	FP_FNSAVE	1	/* fnsave/frstor instructions		*/
66 #define	FP_FXSAVE	2	/* fxsave/fxrstor instructions		*/
67 #define	FP_XSAVE	3	/* xsave/xrstor instructions		*/
68 
69 /*
70  * masks for 80387 control word
71  */
72 #define	FPIM	0x00000001	/* invalid operation			*/
73 #define	FPDM	0x00000002	/* denormalized operand			*/
74 #define	FPZM	0x00000004	/* zero divide				*/
75 #define	FPOM	0x00000008	/* overflow				*/
76 #define	FPUM	0x00000010	/* underflow				*/
77 #define	FPPM	0x00000020	/* precision				*/
78 #define	FPPC	0x00000300	/* precision control			*/
79 #define	FPRC	0x00000C00	/* rounding control			*/
80 #define	FPIC	0x00001000	/* infinity control			*/
81 #define	WFPDE	0x00000080	/* data chain exception			*/
82 
83 /*
84  * (Old symbol compatibility)
85  */
86 #define	FPINV	FPIM
87 #define	FPDNO	FPDM
88 #define	FPZDIV	FPZM
89 #define	FPOVR	FPOM
90 #define	FPUNR	FPUM
91 #define	FPPRE	FPPM
92 
93 /*
94  * precision, rounding, and infinity options in control word
95  */
96 #define	FPSIG24 0x00000000	/* 24-bit significand precision (short) */
97 #define	FPSIG53 0x00000200	/* 53-bit significand precision (long)	*/
98 #define	FPSIG64 0x00000300	/* 64-bit significand precision (temp)	*/
99 #define	FPRTN	0x00000000	/* round to nearest or even		*/
100 #define	FPRD	0x00000400	/* round down				*/
101 #define	FPRU	0x00000800	/* round up				*/
102 #define	FPCHOP	0x00000C00	/* chop (truncate toward zero)		*/
103 #define	FPP	0x00000000	/* projective infinity			*/
104 #define	FPA	0x00001000	/* affine infinity			*/
105 #define	WFPB17	0x00020000	/* bit 17				*/
106 #define	WFPB24	0x00040000	/* bit 24				*/
107 
108 /*
109  * masks for 80387 status word
110  */
111 #define	FPS_IE	0x00000001	/* invalid operation			*/
112 #define	FPS_DE	0x00000002	/* denormalized operand			*/
113 #define	FPS_ZE	0x00000004	/* zero divide				*/
114 #define	FPS_OE	0x00000008	/* overflow				*/
115 #define	FPS_UE	0x00000010	/* underflow				*/
116 #define	FPS_PE	0x00000020	/* precision				*/
117 #define	FPS_SF	0x00000040	/* stack fault				*/
118 #define	FPS_ES	0x00000080	/* error summary bit			*/
119 #define	FPS_C0	0x00000100	/* C0 bit				*/
120 #define	FPS_C1	0x00000200	/* C1 bit				*/
121 #define	FPS_C2	0x00000400	/* C2 bit				*/
122 #define	FPS_TOP	0x00003800	/* top of stack pointer			*/
123 #define	FPS_C3	0x00004000	/* C3 bit				*/
124 #define	FPS_B	0x00008000	/* busy bit				*/
125 
126 /*
127  * Exception flags manually cleared during x87 exception handling.
128  */
129 #define	FPS_SW_EFLAGS	\
130 	(FPS_IE|FPS_DE|FPS_ZE|FPS_OE|FPS_UE|FPS_PE|FPS_SF|FPS_ES|FPS_B)
131 
132 /*
133  * Initial value of FPU control word as per 4th ed. ABI document
134  * - affine infinity
135  * - round to nearest or even
136  * - 64-bit double precision
137  * - all exceptions masked
138  */
139 #define	FPU_CW_INIT	0x133f
140 
141 /*
142  * masks and flags for SSE/SSE2 MXCSR
143  */
144 #define	SSE_IE	0x00000001	/* invalid operation			*/
145 #define	SSE_DE	0x00000002	/* denormalized operand			*/
146 #define	SSE_ZE	0x00000004	/* zero divide				*/
147 #define	SSE_OE	0x00000008	/* overflow				*/
148 #define	SSE_UE	0x00000010	/* underflow				*/
149 #define	SSE_PE	0x00000020	/* precision				*/
150 #define	SSE_DAZ	0x00000040	/* denormals are zero			*/
151 #define	SSE_IM	0x00000080	/* invalid op exception mask		*/
152 #define	SSE_DM	0x00000100	/* denormalize exception mask		*/
153 #define	SSE_ZM	0x00000200	/* zero-divide exception mask		*/
154 #define	SSE_OM	0x00000400	/* overflow exception mask		*/
155 #define	SSE_UM	0x00000800	/* underflow exception mask		*/
156 #define	SSE_PM	0x00001000	/* precision exception mask		*/
157 #define	SSE_RC	0x00006000	/* rounding control			*/
158 #define	SSE_RD	0x00002000	/* rounding control: round down		*/
159 #define	SSE_RU	0x00004000	/* rounding control: round up		*/
160 #define	SSE_FZ	0x00008000	/* flush to zero for masked underflow	*/
161 
162 #define	SSE_MXCSR_EFLAGS	\
163 	(SSE_IE|SSE_DE|SSE_ZE|SSE_OE|SSE_UE|SSE_PE)	/* 0x3f */
164 
165 #define	SSE_MXCSR_INIT	\
166 	(SSE_IM|SSE_DM|SSE_ZM|SSE_OM|SSE_UM|SSE_PM)	/* 0x1f80 */
167 
168 #define	SSE_MXCSR_MASK_DEFAULT	\
169 	(0xffff & ~SSE_DAZ)				/* 0xffbf */
170 
171 #define	SSE_FMT_MXCSR	\
172 	"\20\20fz\17ru\16rd\15pm\14um\13om\12zm\11dm"	\
173 	"\10im\7daz\6pe\5ue\4oe\3ze\2de\1ie"
174 
175 /*
176  * This structure is written to memory by an 'fnsave' instruction
177  */
178 struct fnsave_state {
179 	uint16_t	f_fcw;
180 	uint16_t	__f_ign0;
181 	uint16_t	f_fsw;
182 	uint16_t	__f_ign1;
183 	uint16_t	f_ftw;
184 	uint16_t	__f_ign2;
185 	uint32_t	f_eip;
186 	uint16_t	f_cs;
187 	uint16_t	f_fop;
188 	uint32_t	f_dp;
189 	uint16_t	f_ds;
190 	uint16_t	__f_ign3;
191 	union {
192 		uint16_t fpr_16[5];	/* 80-bits of x87 state */
193 	} f_st[8];
194 };	/* 108 bytes */
195 
196 /*
197  * This structure is written to memory by an 'fxsave' instruction
198  * Note the variant behaviour of this instruction between long mode
199  * and legacy environments!
200  */
201 struct fxsave_state {
202 	uint16_t	fx_fcw;
203 	uint16_t	fx_fsw;
204 	uint16_t	fx_fctw;	/* compressed tag word */
205 	uint16_t	fx_fop;
206 #if defined(__amd64)
207 	uint64_t	fx_rip;
208 	uint64_t	fx_rdp;
209 #else
210 	uint32_t	fx_eip;
211 	uint16_t	fx_cs;
212 	uint16_t	__fx_ign0;
213 	uint32_t	fx_dp;
214 	uint16_t	fx_ds;
215 	uint16_t	__fx_ign1;
216 #endif
217 	uint32_t	fx_mxcsr;
218 	uint32_t	fx_mxcsr_mask;
219 	union {
220 		uint16_t fpr_16[5];	/* 80-bits of x87 state */
221 		u_longlong_t fpr_mmx;	/* 64-bit mmx register */
222 		uint32_t __fpr_pad[4];	/* (pad out to 128-bits) */
223 	} fx_st[8];
224 #if defined(__amd64)
225 	upad128_t	fx_xmm[16];	/* 128-bit registers */
226 	upad128_t	__fx_ign2[6];
227 #else
228 	upad128_t	fx_xmm[8];	/* 128-bit registers */
229 	upad128_t	__fx_ign2[14];
230 #endif
231 } __aligned(16);	/* 512 bytes */
232 
233 /*
234  * This structure represents the header portion of the data layout used by the
235  * 'xsave' instruction variants.  It is documented in section 13.4.2 of the
236  * Intel 64 and IA-32 Architectures Software Developer’s Manual, Volume 1
237  * (IASDv1).  Although "header" is somewhat of a misnomer, considering the data
238  * begins at offset 512 of the xsave area, its contents dictate which portions
239  * of the area are present and how they may be formatted.
240  */
241 struct xsave_header {
242 	uint64_t	xsh_xstate_bv;
243 	uint64_t	xsh_xcomp_bv;
244 	uint64_t	xsh_reserved[6];
245 };
246 
247 /*
248  * This structure is written to memory by one of the 'xsave' instruction
249  * variants. The first 512 bytes are compatible with the format of the 'fxsave'
250  * area.  The extended portion is documented in section 13.4.3.
251  *
252  * Our size is at least AVX_XSAVE_SIZE (832 bytes), which is asserted
253  * statically.  Enabling additional xsave-related CPU features requires an
254  * increase in the size. We dynamically allocate the per-lwp xsave area at
255  * runtime, based on the size needed for the CPU-specific features. This
256  * xsave_state structure simply defines our historical layout for the beginning
257  * of the xsave area. The locations and size of new, extended, components is
258  * determined dynamically by querying the CPU. See the xsave_info structure in
259  * cpuid.c.
260  *
261  * xsave component usage is tracked using bits in the xstate_bv field of the
262  * header. The components are documented in section 13.1 of IASDv1. For easy
263  * reference, this is a summary of the currently defined component bit
264  * definitions:
265  *	x87			0x0001
266  *	SSE			0x0002
267  *	AVX			0x0004
268  *	bndreg (MPX)		0x0008
269  *	bndcsr (MPX)		0x0010
270  *	opmask (AVX512)		0x0020
271  *	zmm hi256 (AVX512)	0x0040
272  *	zmm hi16 (AVX512)	0x0080
273  *	PT			0x0100
274  *	PKRU			0x0200
275  * When xsaveopt_ctxt is being used to save into the xsave_state area, the
276  * xstate_bv field is updated by the xsaveopt instruction to indicate which
277  * elements of the xsave area are active.
278  *
279  * The xcomp_bv field should always be 0, since we do not currently use the
280  * compressed form of xsave (xsavec).
281  */
282 struct xsave_state {
283 	struct fxsave_state	xs_fxsave;	/* 0-511 legacy region */
284 	struct xsave_header	xs_header;	/* 512-575 XSAVE header */
285 	upad128_t		xs_ymm[16];	/* 576 AVX component */
286 } __aligned(64);
287 
288 /*
289  * While AVX_XSTATE_SIZE is the smallest the kernel will allocate for FPU
290  * state-saving, other consumers may constrain themselves to the minimum
291  * possible xsave state structure, which features only the legacy area and the
292  * bare xsave header.
293  */
294 #define	MIN_XSAVE_SIZE	(sizeof (struct fxsave_state) + \
295 			    sizeof (struct xsave_header))
296 
297 /*
298  * Kernel's FPU save area
299  */
300 typedef struct {
301 	union _kfpu_u {
302 		void *kfpu_generic;
303 		struct fxsave_state *kfpu_fx;
304 #if defined(__i386)
305 		struct fnsave_state *kfpu_fn;
306 #endif
307 		struct xsave_state *kfpu_xs;
308 	} kfpu_u;
309 	uint32_t kfpu_status;		/* saved at #mf exception */
310 	uint32_t kfpu_xstatus;		/* saved at #xm exception */
311 } kfpu_t;
312 
313 extern int fp_kind;		/* kind of fp support			*/
314 extern int fp_save_mech;	/* fp save/restore mechanism		*/
315 extern int fpu_exists;		/* FPU hw exists			*/
316 
317 #ifdef _KERNEL
318 
319 extern int fpu_ignored;
320 extern int fpu_pentium_fdivbug;
321 
322 extern uint32_t sse_mxcsr_mask;
323 
324 extern void fpu_probe(void);
325 extern uint_t fpu_initial_probe(void);
326 
327 extern void fpu_auxv_info(int *, size_t *);
328 
329 extern void fpnsave_ctxt(void *);
330 extern void fpxsave_ctxt(void *);
331 extern void xsave_ctxt(void *);
332 extern void xsaveopt_ctxt(void *);
333 extern void fpxsave_excp_clr_ctxt(void *);
334 extern void xsave_excp_clr_ctxt(void *);
335 extern void xsaveopt_excp_clr_ctxt(void *);
336 extern void (*fpsave_ctxt)(void *);
337 extern void (*xsavep)(struct xsave_state *, uint64_t);
338 
339 extern void fpxrestore_ctxt(void *);
340 extern void xrestore_ctxt(void *);
341 extern void (*fprestore_ctxt)(void *);
342 
343 extern void fxsave_insn(struct fxsave_state *);
344 extern void fpsave(struct fnsave_state *);
345 extern void fprestore(struct fnsave_state *);
346 extern void fpxsave(struct fxsave_state *);
347 extern void fpxrestore(struct fxsave_state *);
348 extern void xsave(struct xsave_state *, uint64_t);
349 extern void xsaveopt(struct xsave_state *, uint64_t);
350 extern void xrestore(struct xsave_state *, uint64_t);
351 
352 extern void fpenable(void);
353 extern void fpdisable(void);
354 extern void fpinit(void);
355 
356 extern uint32_t fperr_reset(void);
357 extern uint32_t fpxerr_reset(void);
358 
359 extern uint32_t fpgetcwsw(void);
360 extern uint32_t fpgetmxcsr(void);
361 
362 struct regs;
363 extern int fpexterrflt(struct regs *);
364 extern int fpsimderrflt(struct regs *);
365 extern void fpsetcw(uint16_t, uint32_t);
366 extern void fp_seed(void);
367 extern void fp_exec(void);
368 struct _klwp;
369 extern void fp_lwp_init(struct _klwp *);
370 extern void fp_lwp_cleanup(struct _klwp *);
371 extern void fp_lwp_dup(struct _klwp *);
372 
373 extern const struct fxsave_state sse_initial;
374 extern const struct xsave_state avx_initial;
375 
376 #endif	/* _KERNEL */
377 
378 #ifdef __cplusplus
379 }
380 #endif
381 
382 #endif	/* _SYS_FP_H */
383