linux-user/host/aarch64/host-signal.h

   1 /*
   2  * host-signal.h: signal info dependent on the host architecture
   3  *
   4  * Copyright (c) 2003-2005 Fabrice Bellard
   5  * Copyright (c) 2021 Linaro Limited
   6  *
   7  * This work is licensed under the terms of the GNU LGPL, version 2.1 or later.
   8  * See the COPYING file in the top-level directory.
   9  */
  10
  11 #ifndef AARCH64_HOST_SIGNAL_H
  12 #define AARCH64_HOST_SIGNAL_H
  13
  14 /* Pre-3.16 kernel headers don't have these, so provide fallback definitions */
  15 #ifndef ESR_MAGIC
  16 #define ESR_MAGIC 0x45535201
  17 struct esr_context {
  18     struct _aarch64_ctx head;
  19     uint64_t esr;
  20 };
  21 #endif
  22
  23 static inline struct _aarch64_ctx *first_ctx(ucontext_t *uc)
  24 {
  25     return (struct _aarch64_ctx *)&uc->uc_mcontext.__reserved;
  26 }
  27
  28 static inline struct _aarch64_ctx *next_ctx(struct _aarch64_ctx *hdr)
  29 {
  30     return (struct _aarch64_ctx *)((char *)hdr + hdr->size);
  31 }
  32
  33 static inline uintptr_t host_signal_pc(ucontext_t *uc)
  34 {
  35     return uc->uc_mcontext.pc;
  36 }
  37
  38 static inline void host_signal_set_pc(ucontext_t *uc, uintptr_t pc)
  39 {
  40     uc->uc_mcontext.pc = pc;
  41 }
  42
  43 static inline bool host_signal_write(siginfo_t *info, ucontext_t *uc)
  44 {
  45     struct _aarch64_ctx *hdr;
  46     uint32_t insn;
  47
  48     /* Find the esr_context, which has the WnR bit in it */
  49     for (hdr = first_ctx(uc); hdr->magic; hdr = next_ctx(hdr)) {
  50         if (hdr->magic == ESR_MAGIC) {
  51             struct esr_context const *ec = (struct esr_context const *)hdr;
  52             uint64_t esr = ec->esr;
  53
  54             /* For data aborts ESR.EC is 0b10010x: then bit 6 is the WnR bit */
  55             return extract32(esr, 27, 5) == 0x12 && extract32(esr, 6, 1) == 1;
  56         }
  57     }
  58
  59     /*
  60      * Fall back to parsing instructions; will only be needed
  61      * for really ancient (pre-3.16) kernels.
  62      */
  63     insn = *(uint32_t *)host_signal_pc(uc);
  64
  65     return (insn & 0xbfff0000) == 0x0c000000   /* C3.3.1 */
  66         || (insn & 0xbfe00000) == 0x0c800000   /* C3.3.2 */
  67         || (insn & 0xbfdf0000) == 0x0d000000   /* C3.3.3 */
  68         || (insn & 0xbfc00000) == 0x0d800000   /* C3.3.4 */
  69         || (insn & 0x3f400000) == 0x08000000   /* C3.3.6 */
  70         || (insn & 0x3bc00000) == 0x39000000   /* C3.3.13 */
  71         || (insn & 0x3fc00000) == 0x3d800000   /* ... 128bit */
  72         /* Ignore bits 10, 11 & 21, controlling indexing.  */
  73         || (insn & 0x3bc00000) == 0x38000000   /* C3.3.8-12 */
  74         || (insn & 0x3fe00000) == 0x3c800000   /* ... 128bit */
  75         /* Ignore bits 23 & 24, controlling indexing.  */
  76         || (insn & 0x3a400000) == 0x28000000; /* C3.3.7,14-16 */
  77 }
  78
  79 #endif