xref: /freebsd/contrib/libcxxrt/unwind-arm.h (revision 6966ac055c3b7a39266fb982493330df7a097997)
1 /*
2  * Copyright 2012 David Chisnall. All rights reserved.
3  *
4  * Permission is hereby granted, free of charge, to any person obtaining a copy
5  * of this software and associated documentation files (the "Software"), to
6  * deal in the Software without restriction, including without limitation the
7  * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
8  * sell copies of the Software, and to permit persons to whom the Software is
9  * furnished to do so, subject to the following conditions:
10  *
11  * The above copyright notice and this permission notice shall be
12  * included in all copies or substantial portions of the Software.
13  *
14  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
15  * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
16  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
17  * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
18  * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
19  * OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
20  * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
21  */
22 
23 /* For uint32_t and uint64_t */
24 #include <stdint.h>
25 
26 /**
27  * ARM-specific unwind definitions.  These are taken from the ARM EHABI
28  * specification.
29  */
30  typedef enum
31 {
32 	_URC_OK = 0,                /* operation completed successfully */
33 	_URC_FOREIGN_EXCEPTION_CAUGHT = 1,
34 	_URC_END_OF_STACK = 5,
35 	_URC_HANDLER_FOUND = 6,
36 	_URC_INSTALL_CONTEXT = 7,
37 	_URC_CONTINUE_UNWIND = 8,
38 	_URC_FAILURE = 9,            /* unspecified failure of some kind */
39 	_URC_FATAL_PHASE1_ERROR = _URC_FAILURE
40 } _Unwind_Reason_Code;
41 
42 typedef int _Unwind_Action;
43 
44 typedef uint32_t _Unwind_State;
45 #ifdef __clang__
46 static const _Unwind_State _US_VIRTUAL_UNWIND_FRAME  = 0;
47 static const _Unwind_State _US_UNWIND_FRAME_STARTING = 1;
48 static const _Unwind_State _US_UNWIND_FRAME_RESUME   = 2;
49 static const _Unwind_State _US_ACTION_MASK           = 3;
50 #else // GCC fails at knowing what a constant expression is
51 #	define _US_VIRTUAL_UNWIND_FRAME  0
52 #	define _US_UNWIND_FRAME_STARTING 1
53 #	define _US_UNWIND_FRAME_RESUME   2
54 #	define _US_ACTION_MASK           3
55 #endif
56 
57 typedef struct _Unwind_Context _Unwind_Context;
58 
59 typedef uint32_t _Unwind_EHT_Header;
60 
61 struct _Unwind_Exception
62 {
63 	uint64_t exception_class;
64 	void (*exception_cleanup)(_Unwind_Reason_Code, struct _Unwind_Exception *);
65 	/* Unwinder cache, private fields for the unwinder's use */
66 	struct
67 	{
68 		uint32_t reserved1;
69 		uint32_t reserved2;
70 		uint32_t reserved3;
71 		uint32_t reserved4;
72 		uint32_t reserved5;
73 	/* init reserved1 to 0, then don't touch */
74 	} unwinder_cache;
75 	/* Propagation barrier cache (valid after phase 1): */
76 	struct
77 	{
78 		uint32_t sp;
79 		uint32_t bitpattern[5];
80 	} barrier_cache;
81 	/* Cleanup cache (preserved over cleanup): */
82 	struct
83 	{
84 		uint32_t bitpattern[4];
85 	} cleanup_cache;
86 	/* Pr cache (for pr's benefit): */
87 	struct
88 	{
89 		/** function start address */
90 		uint32_t fnstart;
91 		/** pointer to EHT entry header word */
92 		_Unwind_EHT_Header *ehtp;
93 		/** additional data */
94 		uint32_t additional;
95 		uint32_t reserved1;
96 	} pr_cache;
97 	/** Force alignment of next item to 8-byte boundary */
98 	long long int :0;
99 };
100 
101 /* Unwinding functions */
102 _Unwind_Reason_Code _Unwind_RaiseException(struct _Unwind_Exception *ucbp);
103 void _Unwind_Resume(struct _Unwind_Exception *ucbp);
104 void _Unwind_Complete(struct _Unwind_Exception *ucbp);
105 void _Unwind_DeleteException(struct _Unwind_Exception *ucbp);
106 void *_Unwind_GetLanguageSpecificData(struct _Unwind_Context*);
107 
108 typedef enum
109 {
110 	_UVRSR_OK = 0,
111 	_UVRSR_NOT_IMPLEMENTED = 1,
112 	_UVRSR_FAILED = 2
113 } _Unwind_VRS_Result;
114 typedef enum
115 {
116 	_UVRSC_CORE = 0,
117 	_UVRSC_VFP = 1,
118 	_UVRSC_WMMXD = 3,
119 	_UVRSC_WMMXC = 4
120 } _Unwind_VRS_RegClass;
121 typedef enum
122 {
123 	_UVRSD_UINT32 = 0,
124 	_UVRSD_VFPX = 1,
125 	_UVRSD_UINT64 = 3,
126 	_UVRSD_FLOAT = 4,
127 	_UVRSD_DOUBLE = 5
128 } _Unwind_VRS_DataRepresentation;
129 
130 _Unwind_VRS_Result _Unwind_VRS_Get(_Unwind_Context *context,
131                                    _Unwind_VRS_RegClass regclass,
132                                    uint32_t regno,
133                                    _Unwind_VRS_DataRepresentation representation,
134                                    void *valuep);
135 _Unwind_VRS_Result _Unwind_VRS_Set(_Unwind_Context *context,
136                                    _Unwind_VRS_RegClass regclass,
137                                    uint32_t regno,
138                                    _Unwind_VRS_DataRepresentation representation,
139                                    void *valuep);
140 
141 /* Return the base-address for data references.  */
142 extern unsigned long _Unwind_GetDataRelBase(struct _Unwind_Context *);
143 
144 /* Return the base-address for text references.  */
145 extern unsigned long _Unwind_GetTextRelBase(struct _Unwind_Context *);
146 extern unsigned long _Unwind_GetRegionStart(struct _Unwind_Context *);
147 
148 typedef _Unwind_Reason_Code (*_Unwind_Trace_Fn) (struct _Unwind_Context *,
149 						 void *);
150 extern _Unwind_Reason_Code _Unwind_Backtrace (_Unwind_Trace_Fn, void *);
151 extern _Unwind_Reason_Code
152 	  _Unwind_Resume_or_Rethrow (struct _Unwind_Exception *);
153 
154 /**
155  * The next set of functions are compatibility extensions, implementing Itanium
156  * ABI functions on top of ARM ones.
157  */
158 
159 #define _UA_SEARCH_PHASE	1
160 #define _UA_CLEANUP_PHASE	2
161 #define _UA_HANDLER_FRAME	4
162 #define _UA_FORCE_UNWIND	8
163 
164 static inline unsigned long _Unwind_GetGR(struct _Unwind_Context *context, int reg)
165 {
166 	unsigned long val;
167 	_Unwind_VRS_Get(context, _UVRSC_CORE, reg, _UVRSD_UINT32, &val);
168 	return val;
169 }
170 static inline  void _Unwind_SetGR(struct _Unwind_Context *context, int reg, unsigned long val)
171 {
172 	_Unwind_VRS_Set(context, _UVRSC_CORE, reg, _UVRSD_UINT32, &val);
173 }
174 static inline unsigned long _Unwind_GetIP(_Unwind_Context *context)
175 {
176 	// Low bit store the thumb state - discard it
177 	return _Unwind_GetGR(context, 15) & ~1;
178 }
179 static inline void _Unwind_SetIP(_Unwind_Context *context, unsigned long val)
180 {
181 	// The lowest bit of the instruction pointer indicates whether we're in
182 	// thumb or ARM mode.  This is assumed to be fixed throughout a function,
183 	// so must be propagated when setting the program counter.
184 	unsigned long thumbState = _Unwind_GetGR(context, 15) & 1;
185    _Unwind_SetGR(context, 15, (val | thumbState));
186 }
187 
188 /** GNU API function that unwinds the frame */
189 _Unwind_Reason_Code __gnu_unwind_frame(struct _Unwind_Exception*, struct _Unwind_Context*);
190 
191 
192 #define DECLARE_PERSONALITY_FUNCTION(name) \
193 _Unwind_Reason_Code name(_Unwind_State state,\
194                          struct _Unwind_Exception *exceptionObject,\
195                          struct _Unwind_Context *context);
196 
197 #define BEGIN_PERSONALITY_FUNCTION(name) \
198 _Unwind_Reason_Code name(_Unwind_State state,\
199                          struct _Unwind_Exception *exceptionObject,\
200                          struct _Unwind_Context *context)\
201 {\
202 	int version = 1;\
203 	uint64_t exceptionClass = exceptionObject->exception_class;\
204 	int actions;\
205 	switch (state)\
206 	{\
207 		default: return _URC_FAILURE;\
208 		case _US_VIRTUAL_UNWIND_FRAME:\
209 		{\
210 			actions = _UA_SEARCH_PHASE;\
211 			break;\
212 		}\
213 		case _US_UNWIND_FRAME_STARTING:\
214 		{\
215 			actions = _UA_CLEANUP_PHASE;\
216 			if (exceptionObject->barrier_cache.sp == _Unwind_GetGR(context, 13))\
217 			{\
218 				actions |= _UA_HANDLER_FRAME;\
219 			}\
220 			break;\
221 		}\
222 		case _US_UNWIND_FRAME_RESUME:\
223 		{\
224 			return continueUnwinding(exceptionObject, context);\
225 			break;\
226 		}\
227 	}\
228 	_Unwind_SetGR (context, 12, reinterpret_cast<unsigned long>(exceptionObject));\
229 
230 #define CALL_PERSONALITY_FUNCTION(name) name(state,exceptionObject,context)
231