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_NO_REASON = 0,
33	_URC_OK = 0,                /* operation completed successfully */
34	_URC_FOREIGN_EXCEPTION_CAUGHT = 1,
35	_URC_END_OF_STACK = 5,
36	_URC_HANDLER_FOUND = 6,
37	_URC_INSTALL_CONTEXT = 7,
38	_URC_CONTINUE_UNWIND = 8,
39	_URC_FAILURE = 9,            /* unspecified failure of some kind */
40	_URC_FATAL_PHASE1_ERROR = _URC_FAILURE
41} _Unwind_Reason_Code;
42
43typedef uint32_t _Unwind_State;
44#ifdef __clang__
45static const _Unwind_State _US_VIRTUAL_UNWIND_FRAME  = 0;
46static const _Unwind_State _US_UNWIND_FRAME_STARTING = 1;
47static const _Unwind_State _US_UNWIND_FRAME_RESUME   = 2;
48static const _Unwind_State _US_ACTION_MASK           = 3;
49#else // GCC fails at knowing what a constant expression is
50#	define _US_VIRTUAL_UNWIND_FRAME  0
51#	define _US_UNWIND_FRAME_STARTING 1
52#	define _US_UNWIND_FRAME_RESUME   2
53#	define _US_ACTION_MASK           3
54#endif
55
56typedef struct _Unwind_Context _Unwind_Context;
57
58typedef uint32_t _Unwind_EHT_Header;
59
60struct _Unwind_Exception
61{
62	uint64_t exception_class;
63	void (*exception_cleanup)(_Unwind_Reason_Code, struct _Unwind_Exception *);
64	/* Unwinder cache, private fields for the unwinder's use */
65	struct
66	{
67		uint32_t reserved1;
68		uint32_t reserved2;
69		uint32_t reserved3;
70		uint32_t reserved4;
71		uint32_t reserved5;
72	/* init reserved1 to 0, then don't touch */
73	} unwinder_cache;
74	/* Propagation barrier cache (valid after phase 1): */
75	struct
76	{
77		uint32_t sp;
78		uint32_t bitpattern[5];
79	} barrier_cache;
80	/* Cleanup cache (preserved over cleanup): */
81	struct
82	{
83		uint32_t bitpattern[4];
84	} cleanup_cache;
85	/* Pr cache (for pr's benefit): */
86	struct
87	{
88		/** function start address */
89		uint32_t fnstart;
90		/** pointer to EHT entry header word */
91		_Unwind_EHT_Header *ehtp;
92		/** additional data */
93		uint32_t additional;
94		uint32_t reserved1;
95	} pr_cache;
96	/** Force alignment of next item to 8-byte boundary */
97	long long int :0;
98} __attribute__((__aligned__(8)));
99
100/* Unwinding functions */
101_Unwind_Reason_Code _Unwind_RaiseException(struct _Unwind_Exception *ucbp);
102void _Unwind_Resume(struct _Unwind_Exception *ucbp);
103void _Unwind_Complete(struct _Unwind_Exception *ucbp);
104void _Unwind_DeleteException(struct _Unwind_Exception *ucbp);
105void *_Unwind_GetLanguageSpecificData(struct _Unwind_Context*);
106
107typedef enum
108{
109	_UVRSR_OK = 0,
110	_UVRSR_NOT_IMPLEMENTED = 1,
111	_UVRSR_FAILED = 2
112} _Unwind_VRS_Result;
113typedef enum
114{
115	_UVRSC_CORE = 0,
116	_UVRSC_VFP = 1,
117	_UVRSC_WMMXD = 3,
118	_UVRSC_WMMXC = 4
119} _Unwind_VRS_RegClass;
120typedef enum
121{
122	_UVRSD_UINT32 = 0,
123	_UVRSD_VFPX = 1,
124	_UVRSD_UINT64 = 3,
125	_UVRSD_FLOAT = 4,
126	_UVRSD_DOUBLE = 5
127} _Unwind_VRS_DataRepresentation;
128
129_Unwind_VRS_Result _Unwind_VRS_Get(_Unwind_Context *context,
130                                   _Unwind_VRS_RegClass regclass,
131                                   uint32_t regno,
132                                   _Unwind_VRS_DataRepresentation representation,
133                                   void *valuep);
134_Unwind_VRS_Result _Unwind_VRS_Set(_Unwind_Context *context,
135                                   _Unwind_VRS_RegClass regclass,
136                                   uint32_t regno,
137                                   _Unwind_VRS_DataRepresentation representation,
138                                   void *valuep);
139
140/* Return the base-address for data references.  */
141extern unsigned long _Unwind_GetDataRelBase(struct _Unwind_Context *);
142
143/* Return the base-address for text references.  */
144extern unsigned long _Unwind_GetTextRelBase(struct _Unwind_Context *);
145extern unsigned long _Unwind_GetRegionStart(struct _Unwind_Context *);
146
147typedef _Unwind_Reason_Code (*_Unwind_Trace_Fn) (struct _Unwind_Context *,
148						 void *);
149extern _Unwind_Reason_Code _Unwind_Backtrace (_Unwind_Trace_Fn, void *);
150extern _Unwind_Reason_Code
151	  _Unwind_Resume_or_Rethrow (struct _Unwind_Exception *);
152
153/**
154 * The next set of functions are compatibility extensions, implementing Itanium
155 * ABI functions on top of ARM ones.
156 */
157
158#define _UA_SEARCH_PHASE	1
159#define _UA_CLEANUP_PHASE	2
160#define _UA_HANDLER_FRAME	4
161#define _UA_FORCE_UNWIND	8
162
163static inline unsigned long _Unwind_GetGR(struct _Unwind_Context *context, int reg)
164{
165	unsigned long val;
166	_Unwind_VRS_Get(context, _UVRSC_CORE, reg, _UVRSD_UINT32, &val);
167	return val;
168}
169static inline  void _Unwind_SetGR(struct _Unwind_Context *context, int reg, unsigned long val)
170{
171	_Unwind_VRS_Set(context, _UVRSC_CORE, reg, _UVRSD_UINT32, &val);
172}
173static inline unsigned long _Unwind_GetIP(_Unwind_Context *context)
174{
175	// Low bit store the thumb state - discard it
176	return _Unwind_GetGR(context, 15) & ~1;
177}
178static inline void _Unwind_SetIP(_Unwind_Context *context, unsigned long val)
179{
180	// The lowest bit of the instruction pointer indicates whether we're in
181	// thumb or ARM mode.  This is assumed to be fixed throughout a function,
182	// so must be propagated when setting the program counter.
183	unsigned long thumbState = _Unwind_GetGR(context, 15) & 1;
184   _Unwind_SetGR(context, 15, (val | thumbState));
185}
186
187/** GNU API function that unwinds the frame */
188_Unwind_Reason_Code __gnu_unwind_frame(struct _Unwind_Exception*, struct _Unwind_Context*);
189
190
191#define DECLARE_PERSONALITY_FUNCTION(name) \
192_Unwind_Reason_Code name(_Unwind_State state,\
193                         struct _Unwind_Exception *exceptionObject,\
194                         struct _Unwind_Context *context);
195
196#define BEGIN_PERSONALITY_FUNCTION(name) \
197_Unwind_Reason_Code name(_Unwind_State state,\
198                         struct _Unwind_Exception *exceptionObject,\
199                         struct _Unwind_Context *context)\
200{\
201	int version = 1;\
202	uint64_t exceptionClass = exceptionObject->exception_class;\
203	int actions;\
204	switch (state)\
205	{\
206		default: return _URC_FAILURE;\
207		case _US_VIRTUAL_UNWIND_FRAME:\
208		{\
209			actions = _UA_SEARCH_PHASE;\
210			break;\
211		}\
212		case _US_UNWIND_FRAME_STARTING:\
213		{\
214			actions = _UA_CLEANUP_PHASE;\
215			if (exceptionObject->barrier_cache.sp == _Unwind_GetGR(context, 13))\
216			{\
217				actions |= _UA_HANDLER_FRAME;\
218			}\
219			break;\
220		}\
221		case _US_UNWIND_FRAME_RESUME:\
222		{\
223			return continueUnwinding(exceptionObject, context);\
224			break;\
225		}\
226	}\
227	_Unwind_SetGR (context, 12, reinterpret_cast<unsigned long>(exceptionObject));\
228
229#define CALL_PERSONALITY_FUNCTION(name) name(state,exceptionObject,context)
230