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  */
28 struct 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 struct _aarch64_ctx {
67 	__u32 magic;
68 	__u32 size;
69 };
70 
71 #define FPSIMD_MAGIC	0x46508001
72 
73 struct 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 
92 struct 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 
125 struct 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 
134 struct 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 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 */
253