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/*
* Copyright 2010 Tilera Corporation. All Rights Reserved.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation, version 2.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
* NON INFRINGEMENT. See the GNU General Public License for
* more details.
*/
#ifndef _TILE_BACKTRACE_H
#define _TILE_BACKTRACE_H
#include <linux/types.h>
#include <arch/chip.h>
#if defined(__tile__)
typedef unsigned long VirtualAddress;
#elif CHIP_VA_WIDTH() > 32
typedef unsigned long long VirtualAddress;
#else
typedef unsigned int VirtualAddress;
#endif
/** Reads 'size' bytes from 'address' and writes the data to 'result'.
* Returns true if successful, else false (e.g. memory not readable).
*/
typedef bool (*BacktraceMemoryReader)(void *result,
VirtualAddress address,
unsigned int size,
void *extra);
typedef struct {
/** Current PC. */
VirtualAddress pc;
/** Current stack pointer value. */
VirtualAddress sp;
/** Current frame pointer value (i.e. caller's stack pointer) */
VirtualAddress fp;
/** Internal use only: caller's PC for first frame. */
VirtualAddress initial_frame_caller_pc;
/** Internal use only: callback to read memory. */
BacktraceMemoryReader read_memory_func;
/** Internal use only: arbitrary argument to read_memory_func. */
void *read_memory_func_extra;
} BacktraceIterator;
/** Initializes a backtracer to start from the given location.
*
* If the frame pointer cannot be determined it is set to -1.
*
* @param state The state to be filled in.
* @param read_memory_func A callback that reads memory. If NULL, a default
* value is provided.
* @param read_memory_func_extra An arbitrary argument to read_memory_func.
* @param pc The current PC.
* @param lr The current value of the 'lr' register.
* @param sp The current value of the 'sp' register.
* @param r52 The current value of the 'r52' register.
*/
extern void backtrace_init(BacktraceIterator *state,
BacktraceMemoryReader read_memory_func,
void *read_memory_func_extra,
VirtualAddress pc, VirtualAddress lr,
VirtualAddress sp, VirtualAddress r52);
/** Advances the backtracing state to the calling frame, returning
* true iff successful.
*/
extern bool backtrace_next(BacktraceIterator *state);
typedef enum {
/* We have no idea what the caller's pc is. */
PC_LOC_UNKNOWN,
/* The caller's pc is currently in lr. */
PC_LOC_IN_LR,
/* The caller's pc can be found by dereferencing the caller's sp. */
PC_LOC_ON_STACK
} CallerPCLocation;
typedef enum {
/* We have no idea what the caller's sp is. */
SP_LOC_UNKNOWN,
/* The caller's sp is currently in r52. */
SP_LOC_IN_R52,
/* The caller's sp can be found by adding a certain constant
* to the current value of sp.
*/
SP_LOC_OFFSET
} CallerSPLocation;
/* Bit values ORed into CALLER_* values for info ops. */
enum {
/* Setting the low bit on any of these values means the info op
* applies only to one bundle ago.
*/
ONE_BUNDLE_AGO_FLAG = 1,
/* Setting this bit on a CALLER_SP_* value means the PC is in LR.
* If not set, PC is on the stack.
*/
PC_IN_LR_FLAG = 2,
/* This many of the low bits of a CALLER_SP_* value are for the
* flag bits above.
*/
NUM_INFO_OP_FLAGS = 2,
/* We cannot have one in the memory pipe so this is the maximum. */
MAX_INFO_OPS_PER_BUNDLE = 2
};
/** Internal constants used to define 'info' operands. */
enum {
/* 0 and 1 are reserved, as are all negative numbers. */
CALLER_UNKNOWN_BASE = 2,
CALLER_SP_IN_R52_BASE = 4,
CALLER_SP_OFFSET_BASE = 8,
/* Marks the entry point of certain functions. */
ENTRY_POINT_INFO_OP = 16
};
/** Current backtracer state describing where it thinks the caller is. */
typedef struct {
/*
* Public fields
*/
/* How do we find the caller's PC? */
CallerPCLocation pc_location : 8;
/* How do we find the caller's SP? */
CallerSPLocation sp_location : 8;
/* If sp_location == SP_LOC_OFFSET, then caller_sp == sp +
* loc->sp_offset. Else this field is undefined.
*/
uint16_t sp_offset;
/* In the most recently visited bundle a terminating bundle? */
bool at_terminating_bundle;
/*
* Private fields
*/
/* Will the forward scanner see someone clobbering sp
* (i.e. changing it with something other than addi sp, sp, N?)
*/
bool sp_clobber_follows;
/* Operand to next "visible" info op (no more than one bundle past
* the next terminating bundle), or -32768 if none.
*/
int16_t next_info_operand;
/* Is the info of in next_info_op in the very next bundle? */
bool is_next_info_operand_adjacent;
} CallerLocation;
#endif /* _TILE_BACKTRACE_H */
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