1/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
2/*
3 * Copyright (C) 2012 ARM Ltd.
4 *
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License version 2 as
7 * published by the Free Software Foundation.
8 *
9 * This program is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
12 * GNU General Public License for more details.
13 *
14 * You should have received a copy of the GNU General Public License
15 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
16 */
17#ifndef _UAPI__ASM_SIGCONTEXT_H
18#define _UAPI__ASM_SIGCONTEXT_H
19
20#ifndef __ASSEMBLY__
21
22#include <linux/types.h>
23
24/*
25 * Signal context structure - contains all info to do with the state
26 * before the signal handler was invoked.
27 */
28struct sigcontext {
29	__u64 fault_address;
30	/* AArch64 registers */
31	__u64 regs[31];
32	__u64 sp;
33	__u64 pc;
34	__u64 pstate;
35	/* 4K reserved for FP/SIMD state and future expansion */
36	__u8 __reserved[4096] __attribute__((__aligned__(16)));
37};
38
39/*
40 * Allocation of __reserved[]:
41 * (Note: records do not necessarily occur in the order shown here.)
42 *
43 *	size		description
44 *
45 *	0x210		fpsimd_context
46 *	 0x10		esr_context
47 *	0x8a0		sve_context (vl <= 64) (optional)
48 *	 0x20		extra_context (optional)
49 *	 0x10		terminator (null _aarch64_ctx)
50 *
51 *	0x510		(reserved for future allocation)
52 *
53 * New records that can exceed this space need to be opt-in for userspace, so
54 * that an expanded signal frame is not generated unexpectedly.  The mechanism
55 * for opting in will depend on the extension that generates each new record.
56 * The above table documents the maximum set and sizes of records than can be
57 * generated when userspace does not opt in for any such extension.
58 */
59
60/*
61 * Header to be used at the beginning of structures extending the user
62 * context. Such structures must be placed after the rt_sigframe on the stack
63 * and be 16-byte aligned. The last structure must be a dummy one with the
64 * magic and size set to 0.
65 *
66 * Note that the values allocated for use as magic should be chosen to
67 * be meaningful in ASCII to aid manual parsing, ZA doesn't follow this
68 * convention due to oversight but it should be observed for future additions.
69 */
70struct _aarch64_ctx {
71	__u32 magic;
72	__u32 size;
73};
74
75#define FPSIMD_MAGIC	0x46508001
76
77struct fpsimd_context {
78	struct _aarch64_ctx head;
79	__u32 fpsr;
80	__u32 fpcr;
81	__uint128_t vregs[32];
82};
83
84/*
85 * Note: similarly to all other integer fields, each V-register is stored in an
86 * endianness-dependent format, with the byte at offset i from the start of the
87 * in-memory representation of the register value containing
88 *
89 *    bits [(7 + 8 * i) : (8 * i)] of the register on little-endian hosts; or
90 *    bits [(127 - 8 * i) : (120 - 8 * i)] on big-endian hosts.
91 */
92
93/* ESR_EL1 context */
94#define ESR_MAGIC	0x45535201
95
96struct esr_context {
97	struct _aarch64_ctx head;
98	__u64 esr;
99};
100
101/*
102 * extra_context: describes extra space in the signal frame for
103 * additional structures that don't fit in sigcontext.__reserved[].
104 *
105 * Note:
106 *
107 * 1) fpsimd_context, esr_context and extra_context must be placed in
108 * sigcontext.__reserved[] if present.  They cannot be placed in the
109 * extra space.  Any other record can be placed either in the extra
110 * space or in sigcontext.__reserved[], unless otherwise specified in
111 * this file.
112 *
113 * 2) There must not be more than one extra_context.
114 *
115 * 3) If extra_context is present, it must be followed immediately in
116 * sigcontext.__reserved[] by the terminating null _aarch64_ctx.
117 *
118 * 4) The extra space to which datap points must start at the first
119 * 16-byte aligned address immediately after the terminating null
120 * _aarch64_ctx that follows the extra_context structure in
121 * __reserved[].  The extra space may overrun the end of __reserved[],
122 * as indicated by a sufficiently large value for the size field.
123 *
124 * 5) The extra space must itself be terminated with a null
125 * _aarch64_ctx.
126 */
127#define EXTRA_MAGIC	0x45585401
128
129struct extra_context {
130	struct _aarch64_ctx head;
131	__u64 datap; /* 16-byte aligned pointer to extra space cast to __u64 */
132	__u32 size; /* size in bytes of the extra space */
133	__u32 __reserved[3];
134};
135
136#define SVE_MAGIC	0x53564501
137
138struct sve_context {
139	struct _aarch64_ctx head;
140	__u16 vl;
141	__u16 flags;
142	__u16 __reserved[2];
143};
144
145#define SVE_SIG_FLAG_SM	0x1	/* Context describes streaming mode */
146
147/* TPIDR2_EL0 context */
148#define TPIDR2_MAGIC	0x54504902
149
150struct tpidr2_context {
151	struct _aarch64_ctx head;
152	__u64 tpidr2;
153};
154
155#define ZA_MAGIC	0x54366345
156
157struct za_context {
158	struct _aarch64_ctx head;
159	__u16 vl;
160	__u16 __reserved[3];
161};
162
163#define ZT_MAGIC	0x5a544e01
164
165struct zt_context {
166	struct _aarch64_ctx head;
167	__u16 nregs;
168	__u16 __reserved[3];
169};
170
171#endif /* !__ASSEMBLY__ */
172
173#include <asm/sve_context.h>
174
175/*
176 * The SVE architecture leaves space for future expansion of the
177 * vector length beyond its initial architectural limit of 2048 bits
178 * (16 quadwords).
179 *
180 * See linux/Documentation/arch/arm64/sve.rst for a description of the VL/VQ
181 * terminology.
182 */
183#define SVE_VQ_BYTES		__SVE_VQ_BYTES	/* bytes per quadword */
184
185#define SVE_VQ_MIN		__SVE_VQ_MIN
186#define SVE_VQ_MAX		__SVE_VQ_MAX
187
188#define SVE_VL_MIN		__SVE_VL_MIN
189#define SVE_VL_MAX		__SVE_VL_MAX
190
191#define SVE_NUM_ZREGS		__SVE_NUM_ZREGS
192#define SVE_NUM_PREGS		__SVE_NUM_PREGS
193
194#define sve_vl_valid(vl)	__sve_vl_valid(vl)
195#define sve_vq_from_vl(vl)	__sve_vq_from_vl(vl)
196#define sve_vl_from_vq(vq)	__sve_vl_from_vq(vq)
197
198/*
199 * If the SVE registers are currently live for the thread at signal delivery,
200 * sve_context.head.size >=
201 *	SVE_SIG_CONTEXT_SIZE(sve_vq_from_vl(sve_context.vl))
202 * and the register data may be accessed using the SVE_SIG_*() macros.
203 *
204 * If sve_context.head.size <
205 *	SVE_SIG_CONTEXT_SIZE(sve_vq_from_vl(sve_context.vl)),
206 * the SVE registers were not live for the thread and no register data
207 * is included: in this case, the SVE_SIG_*() macros should not be
208 * used except for this check.
209 *
210 * The same convention applies when returning from a signal: a caller
211 * will need to remove or resize the sve_context block if it wants to
212 * make the SVE registers live when they were previously non-live or
213 * vice-versa.  This may require the caller to allocate fresh
214 * memory and/or move other context blocks in the signal frame.
215 *
216 * Changing the vector length during signal return is not permitted:
217 * sve_context.vl must equal the thread's current vector length when
218 * doing a sigreturn.
219 *
220 * On systems with support for SME the SVE register state may reflect either
221 * streaming or non-streaming mode.  In streaming mode the streaming mode
222 * vector length will be used and the flag SVE_SIG_FLAG_SM will be set in
223 * the flags field. It is permitted to enter or leave streaming mode in
224 * a signal return, applications should take care to ensure that any difference
225 * in vector length between the two modes is handled, including any resizing
226 * and movement of context blocks.
227 *
228 * Note: for all these macros, the "vq" argument denotes the vector length
229 * in quadwords (i.e., units of 128 bits).
230 *
231 * The correct way to obtain vq is to use sve_vq_from_vl(vl).  The
232 * result is valid if and only if sve_vl_valid(vl) is true.  This is
233 * guaranteed for a struct sve_context written by the kernel.
234 *
235 *
236 * Additional macros describe the contents and layout of the payload.
237 * For each, SVE_SIG_x_OFFSET(args) is the start offset relative to
238 * the start of struct sve_context, and SVE_SIG_x_SIZE(args) is the
239 * size in bytes:
240 *
241 *	x	type				description
242 *	-	----				-----------
243 *	REGS					the entire SVE context
244 *
245 *	ZREGS	__uint128_t[SVE_NUM_ZREGS][vq]	all Z-registers
246 *	ZREG	__uint128_t[vq]			individual Z-register Zn
247 *
248 *	PREGS	uint16_t[SVE_NUM_PREGS][vq]	all P-registers
249 *	PREG	uint16_t[vq]			individual P-register Pn
250 *
251 *	FFR	uint16_t[vq]			first-fault status register
252 *
253 * Additional data might be appended in the future.
254 *
255 * Unlike vregs[] in fpsimd_context, each SVE scalable register (Z-, P- or FFR)
256 * is encoded in memory in an endianness-invariant format, with the byte at
257 * offset i from the start of the in-memory representation containing bits
258 * [(7 + 8 * i) : (8 * i)] of the register value.
259 */
260
261#define SVE_SIG_ZREG_SIZE(vq)	__SVE_ZREG_SIZE(vq)
262#define SVE_SIG_PREG_SIZE(vq)	__SVE_PREG_SIZE(vq)
263#define SVE_SIG_FFR_SIZE(vq)	__SVE_FFR_SIZE(vq)
264
265#define SVE_SIG_REGS_OFFSET					\
266	((sizeof(struct sve_context) + (__SVE_VQ_BYTES - 1))	\
267		/ __SVE_VQ_BYTES * __SVE_VQ_BYTES)
268
269#define SVE_SIG_ZREGS_OFFSET \
270		(SVE_SIG_REGS_OFFSET + __SVE_ZREGS_OFFSET)
271#define SVE_SIG_ZREG_OFFSET(vq, n) \
272		(SVE_SIG_REGS_OFFSET + __SVE_ZREG_OFFSET(vq, n))
273#define SVE_SIG_ZREGS_SIZE(vq) __SVE_ZREGS_SIZE(vq)
274
275#define SVE_SIG_PREGS_OFFSET(vq) \
276		(SVE_SIG_REGS_OFFSET + __SVE_PREGS_OFFSET(vq))
277#define SVE_SIG_PREG_OFFSET(vq, n) \
278		(SVE_SIG_REGS_OFFSET + __SVE_PREG_OFFSET(vq, n))
279#define SVE_SIG_PREGS_SIZE(vq) __SVE_PREGS_SIZE(vq)
280
281#define SVE_SIG_FFR_OFFSET(vq) \
282		(SVE_SIG_REGS_OFFSET + __SVE_FFR_OFFSET(vq))
283
284#define SVE_SIG_REGS_SIZE(vq) \
285		(__SVE_FFR_OFFSET(vq) + __SVE_FFR_SIZE(vq))
286
287#define SVE_SIG_CONTEXT_SIZE(vq) \
288		(SVE_SIG_REGS_OFFSET + SVE_SIG_REGS_SIZE(vq))
289
290/*
291 * If the ZA register is enabled for the thread at signal delivery then,
292 * za_context.head.size >= ZA_SIG_CONTEXT_SIZE(sve_vq_from_vl(za_context.vl))
293 * and the register data may be accessed using the ZA_SIG_*() macros.
294 *
295 * If za_context.head.size < ZA_SIG_CONTEXT_SIZE(sve_vq_from_vl(za_context.vl))
296 * then ZA was not enabled and no register data was included in which case
297 * ZA register was not enabled for the thread and no register data
298 * the ZA_SIG_*() macros should not be used except for this check.
299 *
300 * The same convention applies when returning from a signal: a caller
301 * will need to remove or resize the za_context block if it wants to
302 * enable the ZA register when it was previously non-live or vice-versa.
303 * This may require the caller to allocate fresh memory and/or move other
304 * context blocks in the signal frame.
305 *
306 * Changing the vector length during signal return is not permitted:
307 * za_context.vl must equal the thread's current SME vector length when
308 * doing a sigreturn.
309 */
310
311#define ZA_SIG_REGS_OFFSET					\
312	((sizeof(struct za_context) + (__SVE_VQ_BYTES - 1))	\
313		/ __SVE_VQ_BYTES * __SVE_VQ_BYTES)
314
315#define ZA_SIG_REGS_SIZE(vq) ((vq * __SVE_VQ_BYTES) * (vq * __SVE_VQ_BYTES))
316
317#define ZA_SIG_ZAV_OFFSET(vq, n) (ZA_SIG_REGS_OFFSET + \
318				  (SVE_SIG_ZREG_SIZE(vq) * n))
319
320#define ZA_SIG_CONTEXT_SIZE(vq) \
321		(ZA_SIG_REGS_OFFSET + ZA_SIG_REGS_SIZE(vq))
322
323#define ZT_SIG_REG_SIZE 512
324
325#define ZT_SIG_REG_BYTES (ZT_SIG_REG_SIZE / 8)
326
327#define ZT_SIG_REGS_OFFSET sizeof(struct zt_context)
328
329#define ZT_SIG_REGS_SIZE(n) (ZT_SIG_REG_BYTES * n)
330
331#define ZT_SIG_CONTEXT_SIZE(n) \
332	(sizeof(struct zt_context) + ZT_SIG_REGS_SIZE(n))
333
334#endif /* _UAPI__ASM_SIGCONTEXT_H */
335