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 /* The third argument to a SA_SIGINFO handler is ucontext_t. */
15 typedef ucontext_t host_sigcontext;
16
17 /* Pre-3.16 kernel headers don't have these, so provide fallback definitions */
18 #ifndef ESR_MAGIC
19 #define ESR_MAGIC 0x45535201
20 struct esr_context {
21 struct _aarch64_ctx head;
22 uint64_t esr;
23 };
24 #endif
25
first_ctx(host_sigcontext * uc)26 static inline struct _aarch64_ctx *first_ctx(host_sigcontext *uc)
27 {
28 return (struct _aarch64_ctx *)&uc->uc_mcontext.__reserved;
29 }
30
next_ctx(struct _aarch64_ctx * hdr)31 static inline struct _aarch64_ctx *next_ctx(struct _aarch64_ctx *hdr)
32 {
33 return (struct _aarch64_ctx *)((char *)hdr + hdr->size);
34 }
35
host_signal_pc(host_sigcontext * uc)36 static inline uintptr_t host_signal_pc(host_sigcontext *uc)
37 {
38 return uc->uc_mcontext.pc;
39 }
40
host_signal_set_pc(host_sigcontext * uc,uintptr_t pc)41 static inline void host_signal_set_pc(host_sigcontext *uc, uintptr_t pc)
42 {
43 uc->uc_mcontext.pc = pc;
44 }
45
host_signal_mask(host_sigcontext * uc)46 static inline void *host_signal_mask(host_sigcontext *uc)
47 {
48 return &uc->uc_sigmask;
49 }
50
host_signal_write(siginfo_t * info,host_sigcontext * uc)51 static inline bool host_signal_write(siginfo_t *info, host_sigcontext *uc)
52 {
53 struct _aarch64_ctx *hdr;
54 uint32_t insn;
55
56 /* Find the esr_context, which has the WnR bit in it */
57 for (hdr = first_ctx(uc); hdr->magic; hdr = next_ctx(hdr)) {
58 if (hdr->magic == ESR_MAGIC) {
59 struct esr_context const *ec = (struct esr_context const *)hdr;
60 uint64_t esr = ec->esr;
61
62 /* For data aborts ESR.EC is 0b10010x: then bit 6 is the WnR bit */
63 return extract32(esr, 27, 5) == 0x12 && extract32(esr, 6, 1) == 1;
64 }
65 }
66
67 /*
68 * Fall back to parsing instructions; will only be needed
69 * for really ancient (pre-3.16) kernels.
70 */
71 insn = *(uint32_t *)host_signal_pc(uc);
72
73 return (insn & 0xbfff0000) == 0x0c000000 /* C3.3.1 */
74 || (insn & 0xbfe00000) == 0x0c800000 /* C3.3.2 */
75 || (insn & 0xbfdf0000) == 0x0d000000 /* C3.3.3 */
76 || (insn & 0xbfc00000) == 0x0d800000 /* C3.3.4 */
77 || (insn & 0x3f400000) == 0x08000000 /* C3.3.6 */
78 || (insn & 0x3bc00000) == 0x39000000 /* C3.3.13 */
79 || (insn & 0x3fc00000) == 0x3d800000 /* ... 128bit */
80 /* Ignore bits 10, 11 & 21, controlling indexing. */
81 || (insn & 0x3bc00000) == 0x38000000 /* C3.3.8-12 */
82 || (insn & 0x3fe00000) == 0x3c800000 /* ... 128bit */
83 /* Ignore bits 23 & 24, controlling indexing. */
84 || (insn & 0x3a400000) == 0x28000000; /* C3.3.7,14-16 */
85 }
86
87 #endif
88