sigcontext.h 7.5 KB

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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 __ASM_SIGCONTEXT_H
  18. #define __ASM_SIGCONTEXT_H
  19. #ifndef __ASSEMBLY__
  20. #include <linux/types.h>
  21. /*
  22. * Signal context structure - contains all info to do with the state
  23. * before the signal handler was invoked.
  24. */
  25. struct sigcontext {
  26. __u64 fault_address;
  27. /* AArch64 registers */
  28. __u64 regs[31];
  29. __u64 sp;
  30. __u64 pc;
  31. __u64 pstate;
  32. /* 4K reserved for FP/SIMD state and future expansion */
  33. __u8 __reserved[4096] __attribute__((__aligned__(16)));
  34. };
  35. /*
  36. * Allocation of __reserved[]:
  37. * (Note: records do not necessarily occur in the order shown here.)
  38. *
  39. * size description
  40. *
  41. * 0x210 fpsimd_context
  42. * 0x10 esr_context
  43. * 0x8a0 sve_context (vl <= 64) (optional)
  44. * 0x20 extra_context (optional)
  45. * 0x10 terminator (null _aarch64_ctx)
  46. *
  47. * 0x510 (reserved for future allocation)
  48. *
  49. * New records that can exceed this space need to be opt-in for userspace, so
  50. * that an expanded signal frame is not generated unexpectedly. The mechanism
  51. * for opting in will depend on the extension that generates each new record.
  52. * The above table documents the maximum set and sizes of records than can be
  53. * generated when userspace does not opt in for any such extension.
  54. */
  55. /*
  56. * Header to be used at the beginning of structures extending the user
  57. * context. Such structures must be placed after the rt_sigframe on the stack
  58. * and be 16-byte aligned. The last structure must be a dummy one with the
  59. * magic and size set to 0.
  60. */
  61. struct _aarch64_ctx {
  62. __u32 magic;
  63. __u32 size;
  64. };
  65. #define FPSIMD_MAGIC 0x46508001
  66. struct fpsimd_context {
  67. struct _aarch64_ctx head;
  68. __u32 fpsr;
  69. __u32 fpcr;
  70. __uint128_t vregs[32];
  71. };
  72. /* ESR_EL1 context */
  73. #define ESR_MAGIC 0x45535201
  74. struct esr_context {
  75. struct _aarch64_ctx head;
  76. __u64 esr;
  77. };
  78. /*
  79. * extra_context: describes extra space in the signal frame for
  80. * additional structures that don't fit in sigcontext.__reserved[].
  81. *
  82. * Note:
  83. *
  84. * 1) fpsimd_context, esr_context and extra_context must be placed in
  85. * sigcontext.__reserved[] if present. They cannot be placed in the
  86. * extra space. Any other record can be placed either in the extra
  87. * space or in sigcontext.__reserved[], unless otherwise specified in
  88. * this file.
  89. *
  90. * 2) There must not be more than one extra_context.
  91. *
  92. * 3) If extra_context is present, it must be followed immediately in
  93. * sigcontext.__reserved[] by the terminating null _aarch64_ctx.
  94. *
  95. * 4) The extra space to which datap points must start at the first
  96. * 16-byte aligned address immediately after the terminating null
  97. * _aarch64_ctx that follows the extra_context structure in
  98. * __reserved[]. The extra space may overrun the end of __reserved[],
  99. * as indicated by a sufficiently large value for the size field.
  100. *
  101. * 5) The extra space must itself be terminated with a null
  102. * _aarch64_ctx.
  103. */
  104. #define EXTRA_MAGIC 0x45585401
  105. struct extra_context {
  106. struct _aarch64_ctx head;
  107. __u64 datap; /* 16-byte aligned pointer to extra space cast to __u64 */
  108. __u32 size; /* size in bytes of the extra space */
  109. __u32 __reserved[3];
  110. };
  111. #define SVE_MAGIC 0x53564501
  112. struct sve_context {
  113. struct _aarch64_ctx head;
  114. __u16 vl;
  115. __u16 __reserved[3];
  116. };
  117. #endif /* !__ASSEMBLY__ */
  118. /*
  119. * The SVE architecture leaves space for future expansion of the
  120. * vector length beyond its initial architectural limit of 2048 bits
  121. * (16 quadwords).
  122. *
  123. * See linux/Documentation/arm64/sve.txt for a description of the VL/VQ
  124. * terminology.
  125. */
  126. #define SVE_VQ_BYTES 16 /* number of bytes per quadword */
  127. #define SVE_VQ_MIN 1
  128. #define SVE_VQ_MAX 512
  129. #define SVE_VL_MIN (SVE_VQ_MIN * SVE_VQ_BYTES)
  130. #define SVE_VL_MAX (SVE_VQ_MAX * SVE_VQ_BYTES)
  131. #define SVE_NUM_ZREGS 32
  132. #define SVE_NUM_PREGS 16
  133. #define sve_vl_valid(vl) \
  134. ((vl) % SVE_VQ_BYTES == 0 && (vl) >= SVE_VL_MIN && (vl) <= SVE_VL_MAX)
  135. #define sve_vq_from_vl(vl) ((vl) / SVE_VQ_BYTES)
  136. #define sve_vl_from_vq(vq) ((vq) * SVE_VQ_BYTES)
  137. /*
  138. * If the SVE registers are currently live for the thread at signal delivery,
  139. * sve_context.head.size >=
  140. * SVE_SIG_CONTEXT_SIZE(sve_vq_from_vl(sve_context.vl))
  141. * and the register data may be accessed using the SVE_SIG_*() macros.
  142. *
  143. * If sve_context.head.size <
  144. * SVE_SIG_CONTEXT_SIZE(sve_vq_from_vl(sve_context.vl)),
  145. * the SVE registers were not live for the thread and no register data
  146. * is included: in this case, the SVE_SIG_*() macros should not be
  147. * used except for this check.
  148. *
  149. * The same convention applies when returning from a signal: a caller
  150. * will need to remove or resize the sve_context block if it wants to
  151. * make the SVE registers live when they were previously non-live or
  152. * vice-versa. This may require the the caller to allocate fresh
  153. * memory and/or move other context blocks in the signal frame.
  154. *
  155. * Changing the vector length during signal return is not permitted:
  156. * sve_context.vl must equal the thread's current vector length when
  157. * doing a sigreturn.
  158. *
  159. *
  160. * Note: for all these macros, the "vq" argument denotes the SVE
  161. * vector length in quadwords (i.e., units of 128 bits).
  162. *
  163. * The correct way to obtain vq is to use sve_vq_from_vl(vl). The
  164. * result is valid if and only if sve_vl_valid(vl) is true. This is
  165. * guaranteed for a struct sve_context written by the kernel.
  166. *
  167. *
  168. * Additional macros describe the contents and layout of the payload.
  169. * For each, SVE_SIG_x_OFFSET(args) is the start offset relative to
  170. * the start of struct sve_context, and SVE_SIG_x_SIZE(args) is the
  171. * size in bytes:
  172. *
  173. * x type description
  174. * - ---- -----------
  175. * REGS the entire SVE context
  176. *
  177. * ZREGS __uint128_t[SVE_NUM_ZREGS][vq] all Z-registers
  178. * ZREG __uint128_t[vq] individual Z-register Zn
  179. *
  180. * PREGS uint16_t[SVE_NUM_PREGS][vq] all P-registers
  181. * PREG uint16_t[vq] individual P-register Pn
  182. *
  183. * FFR uint16_t[vq] first-fault status register
  184. *
  185. * Additional data might be appended in the future.
  186. */
  187. #define SVE_SIG_ZREG_SIZE(vq) ((__u32)(vq) * SVE_VQ_BYTES)
  188. #define SVE_SIG_PREG_SIZE(vq) ((__u32)(vq) * (SVE_VQ_BYTES / 8))
  189. #define SVE_SIG_FFR_SIZE(vq) SVE_SIG_PREG_SIZE(vq)
  190. #define SVE_SIG_REGS_OFFSET \
  191. ((sizeof(struct sve_context) + (SVE_VQ_BYTES - 1)) \
  192. / SVE_VQ_BYTES * SVE_VQ_BYTES)
  193. #define SVE_SIG_ZREGS_OFFSET SVE_SIG_REGS_OFFSET
  194. #define SVE_SIG_ZREG_OFFSET(vq, n) \
  195. (SVE_SIG_ZREGS_OFFSET + SVE_SIG_ZREG_SIZE(vq) * (n))
  196. #define SVE_SIG_ZREGS_SIZE(vq) \
  197. (SVE_SIG_ZREG_OFFSET(vq, SVE_NUM_ZREGS) - SVE_SIG_ZREGS_OFFSET)
  198. #define SVE_SIG_PREGS_OFFSET(vq) \
  199. (SVE_SIG_ZREGS_OFFSET + SVE_SIG_ZREGS_SIZE(vq))
  200. #define SVE_SIG_PREG_OFFSET(vq, n) \
  201. (SVE_SIG_PREGS_OFFSET(vq) + SVE_SIG_PREG_SIZE(vq) * (n))
  202. #define SVE_SIG_PREGS_SIZE(vq) \
  203. (SVE_SIG_PREG_OFFSET(vq, SVE_NUM_PREGS) - SVE_SIG_PREGS_OFFSET(vq))
  204. #define SVE_SIG_FFR_OFFSET(vq) \
  205. (SVE_SIG_PREGS_OFFSET(vq) + SVE_SIG_PREGS_SIZE(vq))
  206. #define SVE_SIG_REGS_SIZE(vq) \
  207. (SVE_SIG_FFR_OFFSET(vq) + SVE_SIG_FFR_SIZE(vq) - SVE_SIG_REGS_OFFSET)
  208. #define SVE_SIG_CONTEXT_SIZE(vq) (SVE_SIG_REGS_OFFSET + SVE_SIG_REGS_SIZE(vq))
  209. #endif /* __ASM_SIGCONTEXT_H */