[deliverable/linux.git] / arch / tile / include / asm / backtrace.h

/*
 * 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 _ASM_TILE_BACKTRACE_H
#define _ASM_TILE_BACKTRACE_H

#include <linux/types.h>

/* 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,
				      unsigned long address,
				      unsigned int size,
				      void *extra);

typedef struct {
	/* Current PC. */
	unsigned long pc;

	/* Current stack pointer value. */
	unsigned long sp;

	/* Current frame pointer value (i.e. caller's stack pointer) */
	unsigned long fp;

	/* Internal use only: caller's PC for first frame. */
	unsigned long 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;


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,
};


/* 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;

extern void backtrace_init(BacktraceIterator *state,
                          BacktraceMemoryReader read_memory_func,
                          void *read_memory_func_extra,
                          unsigned long pc, unsigned long lr,
                          unsigned long sp, unsigned long r52);


extern bool backtrace_next(BacktraceIterator *state);

#endif /* _ASM_TILE_BACKTRACE_H */
Commit	Line	Data
867e359b CM	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
93013a0f CM	15	#ifndef _ASM_TILE_BACKTRACE_H
93013a0f CM	16	#define _ASM_TILE_BACKTRACE_H
867e359b CM	17
	18	#include <linux/types.h>
	19
93013a0f	20	/* Reads 'size' bytes from 'address' and writes the data to 'result'.
867e359b CM	21	* Returns true if successful, else false (e.g. memory not readable).
	22	*/
	23	typedef bool (BacktraceMemoryReader)(void result,
93013a0f	24	unsigned long address,
867e359b CM	25	unsigned int size,
	26	void *extra);
	27
	28	typedef struct {
93013a0f CM	29	/* Current PC. */
93013a0f CM	30	unsigned long pc;
867e359b	31
93013a0f CM	32	/* Current stack pointer value. */
93013a0f CM	33	unsigned long sp;
867e359b	34
93013a0f CM	35	/* Current frame pointer value (i.e. caller's stack pointer) */
93013a0f CM	36	unsigned long fp;
867e359b	37
93013a0f CM	38	/* Internal use only: caller's PC for first frame. */
93013a0f CM	39	unsigned long initial_frame_caller_pc;
867e359b	40
93013a0f	41	/* Internal use only: callback to read memory. */
867e359b CM	42	BacktraceMemoryReader read_memory_func;
867e359b CM	43
93013a0f	44	/* Internal use only: arbitrary argument to read_memory_func. */
867e359b CM	45	void *read_memory_func_extra;
	46
	47	} BacktraceIterator;
	48
	49
867e359b CM	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
93013a0f	102	/* Internal constants used to define 'info' operands. */
867e359b CM	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
c569cac8	110	CALLER_SP_OFFSET_BASE = 8,
867e359b CM	111	};
	112
	113
93013a0f	114	/* Current backtracer state describing where it thinks the caller is. */
867e359b CM	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
93013a0f CM	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);
867e359b CM	158
867e359b CM	159
93013a0f	160	extern bool backtrace_next(BacktraceIterator *state);
867e359b	161
93013a0f	162	#endif /* _ASM_TILE_BACKTRACE_H */