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Diffstat (limited to 'arch/tile/include/asm/backtrace.h')
| -rw-r--r-- | arch/tile/include/asm/backtrace.h | 193 |
1 files changed, 193 insertions, 0 deletions
diff --git a/arch/tile/include/asm/backtrace.h b/arch/tile/include/asm/backtrace.h new file mode 100644 index 000000000000..6970bfcad549 --- /dev/null +++ b/arch/tile/include/asm/backtrace.h @@ -0,0 +1,193 @@ +/* + * 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 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 +}; + + +/** 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 */ |