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1 | /* |
2 | * Copyright 2010 Tilera Corporation. All Rights Reserved. | |
3 | * | |
4 | * This program is free software; you can redistribute it and/or | |
5 | * modify it under the terms of the GNU General Public License | |
6 | * as published by the Free Software Foundation, version 2. | |
7 | * | |
8 | * This program is distributed in the hope that it will be useful, but | |
9 | * WITHOUT ANY WARRANTY; without even the implied warranty of | |
10 | * MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or | |
11 | * NON INFRINGEMENT. See the GNU General Public License for | |
12 | * more details. | |
13 | */ | |
14 | ||
15 | #ifndef _TILE_BACKTRACE_H | |
16 | #define _TILE_BACKTRACE_H | |
17 | ||
18 | ||
19 | ||
20 | #include <linux/types.h> | |
21 | ||
22 | #include <arch/chip.h> | |
23 | ||
1fcbe027 CM |
24 | #if defined(__tile__) |
25 | typedef unsigned long VirtualAddress; | |
26 | #elif CHIP_VA_WIDTH() > 32 | |
867e359b CM |
27 | typedef unsigned long long VirtualAddress; |
28 | #else | |
29 | typedef unsigned int VirtualAddress; | |
30 | #endif | |
31 | ||
32 | ||
33 | /** Reads 'size' bytes from 'address' and writes the data to 'result'. | |
34 | * Returns true if successful, else false (e.g. memory not readable). | |
35 | */ | |
36 | typedef bool (*BacktraceMemoryReader)(void *result, | |
37 | VirtualAddress address, | |
38 | unsigned int size, | |
39 | void *extra); | |
40 | ||
41 | typedef struct { | |
42 | /** Current PC. */ | |
43 | VirtualAddress pc; | |
44 | ||
45 | /** Current stack pointer value. */ | |
46 | VirtualAddress sp; | |
47 | ||
48 | /** Current frame pointer value (i.e. caller's stack pointer) */ | |
49 | VirtualAddress fp; | |
50 | ||
51 | /** Internal use only: caller's PC for first frame. */ | |
52 | VirtualAddress initial_frame_caller_pc; | |
53 | ||
54 | /** Internal use only: callback to read memory. */ | |
55 | BacktraceMemoryReader read_memory_func; | |
56 | ||
57 | /** Internal use only: arbitrary argument to read_memory_func. */ | |
58 | void *read_memory_func_extra; | |
59 | ||
60 | } BacktraceIterator; | |
61 | ||
62 | ||
63 | /** Initializes a backtracer to start from the given location. | |
64 | * | |
65 | * If the frame pointer cannot be determined it is set to -1. | |
66 | * | |
67 | * @param state The state to be filled in. | |
68 | * @param read_memory_func A callback that reads memory. If NULL, a default | |
69 | * value is provided. | |
70 | * @param read_memory_func_extra An arbitrary argument to read_memory_func. | |
71 | * @param pc The current PC. | |
72 | * @param lr The current value of the 'lr' register. | |
73 | * @param sp The current value of the 'sp' register. | |
74 | * @param r52 The current value of the 'r52' register. | |
75 | */ | |
76 | extern void backtrace_init(BacktraceIterator *state, | |
77 | BacktraceMemoryReader read_memory_func, | |
78 | void *read_memory_func_extra, | |
79 | VirtualAddress pc, VirtualAddress lr, | |
80 | VirtualAddress sp, VirtualAddress r52); | |
81 | ||
82 | ||
83 | /** Advances the backtracing state to the calling frame, returning | |
84 | * true iff successful. | |
85 | */ | |
86 | extern bool backtrace_next(BacktraceIterator *state); | |
87 | ||
88 | ||
89 | typedef enum { | |
90 | ||
91 | /* We have no idea what the caller's pc is. */ | |
92 | PC_LOC_UNKNOWN, | |
93 | ||
94 | /* The caller's pc is currently in lr. */ | |
95 | PC_LOC_IN_LR, | |
96 | ||
97 | /* The caller's pc can be found by dereferencing the caller's sp. */ | |
98 | PC_LOC_ON_STACK | |
99 | ||
100 | } CallerPCLocation; | |
101 | ||
102 | ||
103 | typedef enum { | |
104 | ||
105 | /* We have no idea what the caller's sp is. */ | |
106 | SP_LOC_UNKNOWN, | |
107 | ||
108 | /* The caller's sp is currently in r52. */ | |
109 | SP_LOC_IN_R52, | |
110 | ||
111 | /* The caller's sp can be found by adding a certain constant | |
112 | * to the current value of sp. | |
113 | */ | |
114 | SP_LOC_OFFSET | |
115 | ||
116 | } CallerSPLocation; | |
117 | ||
118 | ||
119 | /* Bit values ORed into CALLER_* values for info ops. */ | |
120 | enum { | |
121 | /* Setting the low bit on any of these values means the info op | |
122 | * applies only to one bundle ago. | |
123 | */ | |
124 | ONE_BUNDLE_AGO_FLAG = 1, | |
125 | ||
126 | /* Setting this bit on a CALLER_SP_* value means the PC is in LR. | |
127 | * If not set, PC is on the stack. | |
128 | */ | |
129 | PC_IN_LR_FLAG = 2, | |
130 | ||
131 | /* This many of the low bits of a CALLER_SP_* value are for the | |
132 | * flag bits above. | |
133 | */ | |
134 | NUM_INFO_OP_FLAGS = 2, | |
135 | ||
136 | /* We cannot have one in the memory pipe so this is the maximum. */ | |
137 | MAX_INFO_OPS_PER_BUNDLE = 2 | |
138 | }; | |
139 | ||
140 | ||
141 | /** Internal constants used to define 'info' operands. */ | |
142 | enum { | |
143 | /* 0 and 1 are reserved, as are all negative numbers. */ | |
144 | ||
145 | CALLER_UNKNOWN_BASE = 2, | |
146 | ||
147 | CALLER_SP_IN_R52_BASE = 4, | |
148 | ||
c569cac8 CM |
149 | CALLER_SP_OFFSET_BASE = 8, |
150 | ||
151 | /* Marks the entry point of certain functions. */ | |
152 | ENTRY_POINT_INFO_OP = 16 | |
867e359b CM |
153 | }; |
154 | ||
155 | ||
156 | /** Current backtracer state describing where it thinks the caller is. */ | |
157 | typedef struct { | |
158 | /* | |
159 | * Public fields | |
160 | */ | |
161 | ||
162 | /* How do we find the caller's PC? */ | |
163 | CallerPCLocation pc_location : 8; | |
164 | ||
165 | /* How do we find the caller's SP? */ | |
166 | CallerSPLocation sp_location : 8; | |
167 | ||
168 | /* If sp_location == SP_LOC_OFFSET, then caller_sp == sp + | |
169 | * loc->sp_offset. Else this field is undefined. | |
170 | */ | |
171 | uint16_t sp_offset; | |
172 | ||
173 | /* In the most recently visited bundle a terminating bundle? */ | |
174 | bool at_terminating_bundle; | |
175 | ||
176 | /* | |
177 | * Private fields | |
178 | */ | |
179 | ||
180 | /* Will the forward scanner see someone clobbering sp | |
181 | * (i.e. changing it with something other than addi sp, sp, N?) | |
182 | */ | |
183 | bool sp_clobber_follows; | |
184 | ||
185 | /* Operand to next "visible" info op (no more than one bundle past | |
186 | * the next terminating bundle), or -32768 if none. | |
187 | */ | |
188 | int16_t next_info_operand; | |
189 | ||
190 | /* Is the info of in next_info_op in the very next bundle? */ | |
191 | bool is_next_info_operand_adjacent; | |
192 | ||
193 | } CallerLocation; | |
194 | ||
195 | ||
196 | ||
197 | ||
198 | #endif /* _TILE_BACKTRACE_H */ |