arch/arm64/include/uapi/asm/sigcontext.h

   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 */