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 24 #if defined(__tile__) 25 typedef unsigned long VirtualAddress; 26 #elif CHIP_VA_WIDTH() > 32 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, 148 149 CALLER_SP_OFFSET_BASE = 8, 150 151 /* Marks the entry point of certain functions. */ 152 ENTRY_POINT_INFO_OP = 16 153 }; 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 */ 199