2 * Copyright 2010 Tilera Corporation. All Rights Reserved.
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.
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
15 #ifndef _TILE_BACKTRACE_H
16 #define _TILE_BACKTRACE_H
20 #include <linux/types.h>
22 #include <arch/chip.h>
24 #if CHIP_VA_WIDTH() > 32
25 typedef unsigned long long VirtualAddress;
27 typedef unsigned int VirtualAddress;
31 /** Reads 'size' bytes from 'address' and writes the data to 'result'.
32 * Returns true if successful, else false (e.g. memory not readable).
34 typedef bool (*BacktraceMemoryReader)(void *result,
35 VirtualAddress address,
43 /** Current stack pointer value. */
46 /** Current frame pointer value (i.e. caller's stack pointer) */
49 /** Internal use only: caller's PC for first frame. */
50 VirtualAddress initial_frame_caller_pc;
52 /** Internal use only: callback to read memory. */
53 BacktraceMemoryReader read_memory_func;
55 /** Internal use only: arbitrary argument to read_memory_func. */
56 void *read_memory_func_extra;
61 /** Initializes a backtracer to start from the given location.
63 * If the frame pointer cannot be determined it is set to -1.
65 * @param state The state to be filled in.
66 * @param read_memory_func A callback that reads memory. If NULL, a default
68 * @param read_memory_func_extra An arbitrary argument to read_memory_func.
69 * @param pc The current PC.
70 * @param lr The current value of the 'lr' register.
71 * @param sp The current value of the 'sp' register.
72 * @param r52 The current value of the 'r52' register.
74 extern void backtrace_init(BacktraceIterator *state,
75 BacktraceMemoryReader read_memory_func,
76 void *read_memory_func_extra,
77 VirtualAddress pc, VirtualAddress lr,
78 VirtualAddress sp, VirtualAddress r52);
81 /** Advances the backtracing state to the calling frame, returning
82 * true iff successful.
84 extern bool backtrace_next(BacktraceIterator *state);
89 /* We have no idea what the caller's pc is. */
92 /* The caller's pc is currently in lr. */
95 /* The caller's pc can be found by dereferencing the caller's sp. */
103 /* We have no idea what the caller's sp is. */
106 /* The caller's sp is currently in r52. */
109 /* The caller's sp can be found by adding a certain constant
110 * to the current value of sp.
117 /* Bit values ORed into CALLER_* values for info ops. */
119 /* Setting the low bit on any of these values means the info op
120 * applies only to one bundle ago.
122 ONE_BUNDLE_AGO_FLAG = 1,
124 /* Setting this bit on a CALLER_SP_* value means the PC is in LR.
125 * If not set, PC is on the stack.
129 /* This many of the low bits of a CALLER_SP_* value are for the
132 NUM_INFO_OP_FLAGS = 2,
134 /* We cannot have one in the memory pipe so this is the maximum. */
135 MAX_INFO_OPS_PER_BUNDLE = 2
139 /** Internal constants used to define 'info' operands. */
141 /* 0 and 1 are reserved, as are all negative numbers. */
143 CALLER_UNKNOWN_BASE = 2,
145 CALLER_SP_IN_R52_BASE = 4,
147 CALLER_SP_OFFSET_BASE = 8
151 /** Current backtracer state describing where it thinks the caller is. */
157 /* How do we find the caller's PC? */
158 CallerPCLocation pc_location : 8;
160 /* How do we find the caller's SP? */
161 CallerSPLocation sp_location : 8;
163 /* If sp_location == SP_LOC_OFFSET, then caller_sp == sp +
164 * loc->sp_offset. Else this field is undefined.
168 /* In the most recently visited bundle a terminating bundle? */
169 bool at_terminating_bundle;
175 /* Will the forward scanner see someone clobbering sp
176 * (i.e. changing it with something other than addi sp, sp, N?)
178 bool sp_clobber_follows;
180 /* Operand to next "visible" info op (no more than one bundle past
181 * the next terminating bundle), or -32768 if none.
183 int16_t next_info_operand;
185 /* Is the info of in next_info_op in the very next bundle? */
186 bool is_next_info_operand_adjacent;
193 #endif /* _TILE_BACKTRACE_H */