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 /* ESR_EL1 context */
81 #define ESR_MAGIC	0x45535201
82 
83 struct esr_context {
84 	struct _aarch64_ctx head;
85 	__u64 esr;
86 };
87 
88 /*
89  * extra_context: describes extra space in the signal frame for
90  * additional structures that don't fit in sigcontext.__reserved[].
91  *
92  * Note:
93  *
94  * 1) fpsimd_context, esr_context and extra_context must be placed in
95  * sigcontext.__reserved[] if present.  They cannot be placed in the
96  * extra space.  Any other record can be placed either in the extra
97  * space or in sigcontext.__reserved[], unless otherwise specified in
98  * this file.
99  *
100  * 2) There must not be more than one extra_context.
101  *
102  * 3) If extra_context is present, it must be followed immediately in
103  * sigcontext.__reserved[] by the terminating null _aarch64_ctx.
104  *
105  * 4) The extra space to which datap points must start at the first
106  * 16-byte aligned address immediately after the terminating null
107  * _aarch64_ctx that follows the extra_context structure in
108  * __reserved[].  The extra space may overrun the end of __reserved[],
109  * as indicated by a sufficiently large value for the size field.
110  *
111  * 5) The extra space must itself be terminated with a null
112  * _aarch64_ctx.
113  */
114 #define EXTRA_MAGIC	0x45585401
115 
116 struct extra_context {
117 	struct _aarch64_ctx head;
118 	__u64 datap; /* 16-byte aligned pointer to extra space cast to __u64 */
119 	__u32 size; /* size in bytes of the extra space */
120 	__u32 __reserved[3];
121 };
122 
123 #define SVE_MAGIC	0x53564501
124 
125 struct sve_context {
126 	struct _aarch64_ctx head;
127 	__u16 vl;
128 	__u16 __reserved[3];
129 };
130 
131 #endif /* !__ASSEMBLY__ */
132 
133 /*
134  * The SVE architecture leaves space for future expansion of the
135  * vector length beyond its initial architectural limit of 2048 bits
136  * (16 quadwords).
137  *
138  * See linux/Documentation/arm64/sve.txt for a description of the VL/VQ
139  * terminology.
140  */
141 #define SVE_VQ_BYTES		16	/* number of bytes per quadword */
142 
143 #define SVE_VQ_MIN		1
144 #define SVE_VQ_MAX		512
145 
146 #define SVE_VL_MIN		(SVE_VQ_MIN * SVE_VQ_BYTES)
147 #define SVE_VL_MAX		(SVE_VQ_MAX * SVE_VQ_BYTES)
148 
149 #define SVE_NUM_ZREGS		32
150 #define SVE_NUM_PREGS		16
151 
152 #define sve_vl_valid(vl) \
153 	((vl) % SVE_VQ_BYTES == 0 && (vl) >= SVE_VL_MIN && (vl) <= SVE_VL_MAX)
154 #define sve_vq_from_vl(vl)	((vl) / SVE_VQ_BYTES)
155 #define sve_vl_from_vq(vq)	((vq) * SVE_VQ_BYTES)
156 
157 /*
158  * If the SVE registers are currently live for the thread at signal delivery,
159  * sve_context.head.size >=
160  *	SVE_SIG_CONTEXT_SIZE(sve_vq_from_vl(sve_context.vl))
161  * and the register data may be accessed using the SVE_SIG_*() macros.
162  *
163  * If sve_context.head.size <
164  *	SVE_SIG_CONTEXT_SIZE(sve_vq_from_vl(sve_context.vl)),
165  * the SVE registers were not live for the thread and no register data
166  * is included: in this case, the SVE_SIG_*() macros should not be
167  * used except for this check.
168  *
169  * The same convention applies when returning from a signal: a caller
170  * will need to remove or resize the sve_context block if it wants to
171  * make the SVE registers live when they were previously non-live or
172  * vice-versa.  This may require the the caller to allocate fresh
173  * memory and/or move other context blocks in the signal frame.
174  *
175  * Changing the vector length during signal return is not permitted:
176  * sve_context.vl must equal the thread's current vector length when
177  * doing a sigreturn.
178  *
179  *
180  * Note: for all these macros, the "vq" argument denotes the SVE
181  * vector length in quadwords (i.e., units of 128 bits).
182  *
183  * The correct way to obtain vq is to use sve_vq_from_vl(vl).  The
184  * result is valid if and only if sve_vl_valid(vl) is true.  This is
185  * guaranteed for a struct sve_context written by the kernel.
186  *
187  *
188  * Additional macros describe the contents and layout of the payload.
189  * For each, SVE_SIG_x_OFFSET(args) is the start offset relative to
190  * the start of struct sve_context, and SVE_SIG_x_SIZE(args) is the
191  * size in bytes:
192  *
193  *	x	type				description
194  *	-	----				-----------
195  *	REGS					the entire SVE context
196  *
197  *	ZREGS	__uint128_t[SVE_NUM_ZREGS][vq]	all Z-registers
198  *	ZREG	__uint128_t[vq]			individual Z-register Zn
199  *
200  *	PREGS	uint16_t[SVE_NUM_PREGS][vq]	all P-registers
201  *	PREG	uint16_t[vq]			individual P-register Pn
202  *
203  *	FFR	uint16_t[vq]			first-fault status register
204  *
205  * Additional data might be appended in the future.
206  */
207 
208 #define SVE_SIG_ZREG_SIZE(vq)	((__u32)(vq) * SVE_VQ_BYTES)
209 #define SVE_SIG_PREG_SIZE(vq)	((__u32)(vq) * (SVE_VQ_BYTES / 8))
210 #define SVE_SIG_FFR_SIZE(vq)	SVE_SIG_PREG_SIZE(vq)
211 
212 #define SVE_SIG_REGS_OFFSET					\
213 	((sizeof(struct sve_context) + (SVE_VQ_BYTES - 1))	\
214 		/ SVE_VQ_BYTES * SVE_VQ_BYTES)
215 
216 #define SVE_SIG_ZREGS_OFFSET	SVE_SIG_REGS_OFFSET
217 #define SVE_SIG_ZREG_OFFSET(vq, n) \
218 	(SVE_SIG_ZREGS_OFFSET + SVE_SIG_ZREG_SIZE(vq) * (n))
219 #define SVE_SIG_ZREGS_SIZE(vq) \
220 	(SVE_SIG_ZREG_OFFSET(vq, SVE_NUM_ZREGS) - SVE_SIG_ZREGS_OFFSET)
221 
222 #define SVE_SIG_PREGS_OFFSET(vq) \
223 	(SVE_SIG_ZREGS_OFFSET + SVE_SIG_ZREGS_SIZE(vq))
224 #define SVE_SIG_PREG_OFFSET(vq, n) \
225 	(SVE_SIG_PREGS_OFFSET(vq) + SVE_SIG_PREG_SIZE(vq) * (n))
226 #define SVE_SIG_PREGS_SIZE(vq) \
227 	(SVE_SIG_PREG_OFFSET(vq, SVE_NUM_PREGS) - SVE_SIG_PREGS_OFFSET(vq))
228 
229 #define SVE_SIG_FFR_OFFSET(vq) \
230 	(SVE_SIG_PREGS_OFFSET(vq) + SVE_SIG_PREGS_SIZE(vq))
231 
232 #define SVE_SIG_REGS_SIZE(vq) \
233 	(SVE_SIG_FFR_OFFSET(vq) + SVE_SIG_FFR_SIZE(vq) - SVE_SIG_REGS_OFFSET)
234 
235 #define SVE_SIG_CONTEXT_SIZE(vq) (SVE_SIG_REGS_OFFSET + SVE_SIG_REGS_SIZE(vq))
236 
237 
238 #endif /* _UAPI__ASM_SIGCONTEXT_H */
239