3 * Handle signal handler differences across platforms
5 * Copyright (C) 2013 Xamarin Inc
6 * Licensed under the MIT license. See LICENSE file in the project root for full license information.
9 #ifndef __MONO_SIGNAL_HANDLER_H__
10 #define __MONO_SIGNAL_HANDLER_H__
15 * When a signal is delivered to a thread on a Krait Android device
16 * that's in the middle of skipping over an "IT" block, such as this
19 * 0x40184ef0 <dlfree+1308>: ldr r1, [r3, #0]
20 * 0x40184ef2 <dlfree+1310>: add.w r5, r12, r2, lsl #3
21 * 0x40184ef6 <dlfree+1314>: lsls.w r2, r0, r2
22 * 0x40184efa <dlfree+1318>: tst r2, r1
23 * ### this is the IT instruction
24 * 0x40184efc <dlfree+1320>: itt eq
25 * 0x40184efe <dlfree+1322>: orreq r2, r1
26 * ### signal arrives here
27 * 0x40184f00 <dlfree+1324>: streq r2, [r3, #0]
28 * 0x40184f02 <dlfree+1326>: beq.n 0x40184f1a <dlfree+1350>
29 * 0x40184f04 <dlfree+1328>: ldr r2, [r5, #8]
30 * 0x40184f06 <dlfree+1330>: ldr r3, [r3, #16]
32 * then the first few (at most four, one would assume) instructions of
33 * the signal handler (!) might be skipped. They happen to be the
34 * push of the frame pointer and return address, so once the signal
35 * handler has done its work, it returns into a SIGSEGV.
38 #if defined (TARGET_ARM) && defined (HAVE_ARMV7) && defined (TARGET_ANDROID)
39 #define KRAIT_IT_BUG_WORKAROUND 1
42 #ifdef KRAIT_IT_BUG_WORKAROUND
43 #define MONO_SIGNAL_HANDLER_FUNC(access, name, arglist) \
44 static void __krait_ ## name arglist; \
45 __attribute__ ((__naked__)) access void \
56 static __attribute__ ((__used__)) void __krait_ ## name arglist
60 #ifndef MONO_SIGNAL_HANDLER_FUNC
61 #define MONO_SIGNAL_HANDLER_FUNC(access, name, arglist) access void name arglist
65 * Macros to work around signal handler differences on various platforms.
67 * To declare a signal handler function:
68 * void MONO_SIG_HANDLER_SIGNATURE (handler_func)
69 * To define a signal handler function:
70 * MONO_SIG_HANDLER_FUNC(access, name)
71 * To call another signal handler function:
72 * handler_func (MONO_SIG_HANDLER_PARAMS);
73 * To obtain the signal number:
74 * int signo = MONO_SIG_HANDLER_GET_SIGNO ();
75 * To obtain the signal context:
76 * MONO_SIG_HANDLER_GET_CONTEXT ().
77 * This will define a variable name 'ctx'.
81 #define MONO_SIG_HANDLER_SIGNATURE(ftn) ftn (int _dummy, EXCEPTION_POINTERS *_info, void *context)
82 #define MONO_SIG_HANDLER_FUNC(access, ftn) MONO_SIGNAL_HANDLER_FUNC (access, ftn, (int _dummy, EXCEPTION_POINTERS *_info, void *context))
83 #define MONO_SIG_HANDLER_PARAMS _dummy, _info, context
84 #define MONO_SIG_HANDLER_GET_SIGNO() (_dummy)
85 #define MONO_SIG_HANDLER_GET_INFO() (_info)
86 #define MONO_SIG_HANDLER_INFO_TYPE EXCEPTION_POINTERS
87 /* seh_vectored_exception_handler () passes in a CONTEXT* */
88 #define MONO_SIG_HANDLER_GET_CONTEXT \
92 #define MONO_SIG_HANDLER_SIGNATURE(ftn) ftn (int _dummy, siginfo_t *_info, void *context)
93 #define MONO_SIG_HANDLER_FUNC(access, ftn) MONO_SIGNAL_HANDLER_FUNC (access, ftn, (int _dummy, siginfo_t *_info, void *context))
94 #define MONO_SIG_HANDLER_PARAMS _dummy, _info, context
95 #define MONO_SIG_HANDLER_GET_SIGNO() (_dummy)
96 #define MONO_SIG_HANDLER_GET_INFO() (_info)
97 #define MONO_SIG_HANDLER_INFO_TYPE siginfo_t
98 #define MONO_SIG_HANDLER_GET_CONTEXT \