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 _ASM_TILE_BACKTRACE_H 16 #define _ASM_TILE_BACKTRACE_H 17 18 #include <linux/types.h> 19 20 /* Reads 'size' bytes from 'address' and writes the data to 'result'. 21 * Returns true if successful, else false (e.g. memory not readable). 22 */ 23 typedef bool (*BacktraceMemoryReader)(void *result, 24 unsigned long address, 25 unsigned int size, 26 void *extra); 27 28 typedef struct { 29 /* Current PC. */ 30 unsigned long pc; 31 32 /* Current stack pointer value. */ 33 unsigned long sp; 34 35 /* Current frame pointer value (i.e. caller's stack pointer) */ 36 unsigned long fp; 37 38 /* Internal use only: caller's PC for first frame. */ 39 unsigned long initial_frame_caller_pc; 40 41 /* Internal use only: callback to read memory. */ 42 BacktraceMemoryReader read_memory_func; 43 44 /* Internal use only: arbitrary argument to read_memory_func. */ 45 void *read_memory_func_extra; 46 47 } BacktraceIterator; 48 49 50 typedef enum { 51 52 /* We have no idea what the caller's pc is. */ 53 PC_LOC_UNKNOWN, 54 55 /* The caller's pc is currently in lr. */ 56 PC_LOC_IN_LR, 57 58 /* The caller's pc can be found by dereferencing the caller's sp. */ 59 PC_LOC_ON_STACK 60 61 } CallerPCLocation; 62 63 64 typedef enum { 65 66 /* We have no idea what the caller's sp is. */ 67 SP_LOC_UNKNOWN, 68 69 /* The caller's sp is currently in r52. */ 70 SP_LOC_IN_R52, 71 72 /* The caller's sp can be found by adding a certain constant 73 * to the current value of sp. 74 */ 75 SP_LOC_OFFSET 76 77 } CallerSPLocation; 78 79 80 /* Bit values ORed into CALLER_* values for info ops. */ 81 enum { 82 /* Setting the low bit on any of these values means the info op 83 * applies only to one bundle ago. 84 */ 85 ONE_BUNDLE_AGO_FLAG = 1, 86 87 /* Setting this bit on a CALLER_SP_* value means the PC is in LR. 88 * If not set, PC is on the stack. 89 */ 90 PC_IN_LR_FLAG = 2, 91 92 /* This many of the low bits of a CALLER_SP_* value are for the 93 * flag bits above. 94 */ 95 NUM_INFO_OP_FLAGS = 2, 96 97 /* We cannot have one in the memory pipe so this is the maximum. */ 98 MAX_INFO_OPS_PER_BUNDLE = 2 99 }; 100 101 102 /* Internal constants used to define 'info' operands. */ 103 enum { 104 /* 0 and 1 are reserved, as are all negative numbers. */ 105 106 CALLER_UNKNOWN_BASE = 2, 107 108 CALLER_SP_IN_R52_BASE = 4, 109 110 CALLER_SP_OFFSET_BASE = 8, 111 }; 112 113 114 /* Current backtracer state describing where it thinks the caller is. */ 115 typedef struct { 116 /* 117 * Public fields 118 */ 119 120 /* How do we find the caller's PC? */ 121 CallerPCLocation pc_location : 8; 122 123 /* How do we find the caller's SP? */ 124 CallerSPLocation sp_location : 8; 125 126 /* If sp_location == SP_LOC_OFFSET, then caller_sp == sp + 127 * loc->sp_offset. Else this field is undefined. 128 */ 129 uint16_t sp_offset; 130 131 /* In the most recently visited bundle a terminating bundle? */ 132 bool at_terminating_bundle; 133 134 /* 135 * Private fields 136 */ 137 138 /* Will the forward scanner see someone clobbering sp 139 * (i.e. changing it with something other than addi sp, sp, N?) 140 */ 141 bool sp_clobber_follows; 142 143 /* Operand to next "visible" info op (no more than one bundle past 144 * the next terminating bundle), or -32768 if none. 145 */ 146 int16_t next_info_operand; 147 148 /* Is the info of in next_info_op in the very next bundle? */ 149 bool is_next_info_operand_adjacent; 150 151 } CallerLocation; 152 153 extern void backtrace_init(BacktraceIterator *state, 154 BacktraceMemoryReader read_memory_func, 155 void *read_memory_func_extra, 156 unsigned long pc, unsigned long lr, 157 unsigned long sp, unsigned long r52); 158 159 160 extern bool backtrace_next(BacktraceIterator *state); 161 162 #endif /* _ASM_TILE_BACKTRACE_H */ 163