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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 */
66struct _aarch64_ctx {
67 __u32 magic;
68 __u32 size;
69};
70
71#define FPSIMD_MAGIC 0x46508001
72
73struct fpsimd_context {
74 struct _aarch64_ctx head;
75 __u32 fpsr;
76 __u32 fpcr;
77 __uint128_t vregs[32];
78};
79
80/*
81 * Note: similarly to all other integer fields, each V-register is stored in an
82 * endianness-dependent format, with the byte at offset i from the start of the
83 * in-memory representation of the register value containing
84 *
85 * bits [(7 + 8 * i) : (8 * i)] of the register on little-endian hosts; or
86 * bits [(127 - 8 * i) : (120 - 8 * i)] on big-endian hosts.
87 */
88
89/* ESR_EL1 context */
90#define ESR_MAGIC 0x45535201
91
92struct esr_context {
93 struct _aarch64_ctx head;
94 __u64 esr;
95};
96
97/*
98 * extra_context: describes extra space in the signal frame for
99 * additional structures that don't fit in sigcontext.__reserved[].
100 *
101 * Note:
102 *
103 * 1) fpsimd_context, esr_context and extra_context must be placed in
104 * sigcontext.__reserved[] if present. They cannot be placed in the
105 * extra space. Any other record can be placed either in the extra
106 * space or in sigcontext.__reserved[], unless otherwise specified in
107 * this file.
108 *
109 * 2) There must not be more than one extra_context.
110 *
111 * 3) If extra_context is present, it must be followed immediately in
112 * sigcontext.__reserved[] by the terminating null _aarch64_ctx.
113 *
114 * 4) The extra space to which datap points must start at the first
115 * 16-byte aligned address immediately after the terminating null
116 * _aarch64_ctx that follows the extra_context structure in
117 * __reserved[]. The extra space may overrun the end of __reserved[],
118 * as indicated by a sufficiently large value for the size field.
119 *
120 * 5) The extra space must itself be terminated with a null
121 * _aarch64_ctx.
122 */
123#define EXTRA_MAGIC 0x45585401
124
125struct extra_context {
126 struct _aarch64_ctx head;
127 __u64 datap; /* 16-byte aligned pointer to extra space cast to __u64 */
128 __u32 size; /* size in bytes of the extra space */
129 __u32 __reserved[3];
130};
131
132#define SVE_MAGIC 0x53564501
133
134struct sve_context {
135 struct _aarch64_ctx head;
136 __u16 vl;
137 __u16 __reserved[3];
138};
139
140#endif /* !__ASSEMBLY__ */
141
142#include <asm/sve_context.h>
143
144/*
145 * The SVE architecture leaves space for future expansion of the
146 * vector length beyond its initial architectural limit of 2048 bits
147 * (16 quadwords).
148 *
149 * See linux/Documentation/arm64/sve.rst for a description of the VL/VQ
150 * terminology.
151 */
152#define SVE_VQ_BYTES __SVE_VQ_BYTES /* bytes per quadword */
153
154#define SVE_VQ_MIN __SVE_VQ_MIN
155#define SVE_VQ_MAX __SVE_VQ_MAX
156
157#define SVE_VL_MIN __SVE_VL_MIN
158#define SVE_VL_MAX __SVE_VL_MAX
159
160#define SVE_NUM_ZREGS __SVE_NUM_ZREGS
161#define SVE_NUM_PREGS __SVE_NUM_PREGS
162
163#define sve_vl_valid(vl) __sve_vl_valid(vl)
164#define sve_vq_from_vl(vl) __sve_vq_from_vl(vl)
165#define sve_vl_from_vq(vq) __sve_vl_from_vq(vq)
166
167/*
168 * If the SVE registers are currently live for the thread at signal delivery,
169 * sve_context.head.size >=
170 * SVE_SIG_CONTEXT_SIZE(sve_vq_from_vl(sve_context.vl))
171 * and the register data may be accessed using the SVE_SIG_*() macros.
172 *
173 * If sve_context.head.size <
174 * SVE_SIG_CONTEXT_SIZE(sve_vq_from_vl(sve_context.vl)),
175 * the SVE registers were not live for the thread and no register data
176 * is included: in this case, the SVE_SIG_*() macros should not be
177 * used except for this check.
178 *
179 * The same convention applies when returning from a signal: a caller
180 * will need to remove or resize the sve_context block if it wants to
181 * make the SVE registers live when they were previously non-live or
182 * vice-versa. This may require the the caller to allocate fresh
183 * memory and/or move other context blocks in the signal frame.
184 *
185 * Changing the vector length during signal return is not permitted:
186 * sve_context.vl must equal the thread's current vector length when
187 * doing a sigreturn.
188 *
189 *
190 * Note: for all these macros, the "vq" argument denotes the SVE
191 * vector length in quadwords (i.e., units of 128 bits).
192 *
193 * The correct way to obtain vq is to use sve_vq_from_vl(vl). The
194 * result is valid if and only if sve_vl_valid(vl) is true. This is
195 * guaranteed for a struct sve_context written by the kernel.
196 *
197 *
198 * Additional macros describe the contents and layout of the payload.
199 * For each, SVE_SIG_x_OFFSET(args) is the start offset relative to
200 * the start of struct sve_context, and SVE_SIG_x_SIZE(args) is the
201 * size in bytes:
202 *
203 * x type description
204 * - ---- -----------
205 * REGS the entire SVE context
206 *
207 * ZREGS __uint128_t[SVE_NUM_ZREGS][vq] all Z-registers
208 * ZREG __uint128_t[vq] individual Z-register Zn
209 *
210 * PREGS uint16_t[SVE_NUM_PREGS][vq] all P-registers
211 * PREG uint16_t[vq] individual P-register Pn
212 *
213 * FFR uint16_t[vq] first-fault status register
214 *
215 * Additional data might be appended in the future.
216 *
217 * Unlike vregs[] in fpsimd_context, each SVE scalable register (Z-, P- or FFR)
218 * is encoded in memory in an endianness-invariant format, with the byte at
219 * offset i from the start of the in-memory representation containing bits
220 * [(7 + 8 * i) : (8 * i)] of the register value.
221 */
222
223#define SVE_SIG_ZREG_SIZE(vq) __SVE_ZREG_SIZE(vq)
224#define SVE_SIG_PREG_SIZE(vq) __SVE_PREG_SIZE(vq)
225#define SVE_SIG_FFR_SIZE(vq) __SVE_FFR_SIZE(vq)
226
227#define SVE_SIG_REGS_OFFSET \
228 ((sizeof(struct sve_context) + (__SVE_VQ_BYTES - 1)) \
229 / __SVE_VQ_BYTES * __SVE_VQ_BYTES)
230
231#define SVE_SIG_ZREGS_OFFSET \
232 (SVE_SIG_REGS_OFFSET + __SVE_ZREGS_OFFSET)
233#define SVE_SIG_ZREG_OFFSET(vq, n) \
234 (SVE_SIG_REGS_OFFSET + __SVE_ZREG_OFFSET(vq, n))
235#define SVE_SIG_ZREGS_SIZE(vq) __SVE_ZREGS_SIZE(vq)
236
237#define SVE_SIG_PREGS_OFFSET(vq) \
238 (SVE_SIG_REGS_OFFSET + __SVE_PREGS_OFFSET(vq))
239#define SVE_SIG_PREG_OFFSET(vq, n) \
240 (SVE_SIG_REGS_OFFSET + __SVE_PREG_OFFSET(vq, n))
241#define SVE_SIG_PREGS_SIZE(vq) __SVE_PREGS_SIZE(vq)
242
243#define SVE_SIG_FFR_OFFSET(vq) \
244 (SVE_SIG_REGS_OFFSET + __SVE_FFR_OFFSET(vq))
245
246#define SVE_SIG_REGS_SIZE(vq) \
247 (__SVE_FFR_OFFSET(vq) + __SVE_FFR_SIZE(vq))
248
249#define SVE_SIG_CONTEXT_SIZE(vq) \
250 (SVE_SIG_REGS_OFFSET + SVE_SIG_REGS_SIZE(vq))
251
252#endif /* _UAPI__ASM_SIGCONTEXT_H */