| 1 | /* |
| 2 | * Stacktrace support for Hexagon |
| 3 | * |
| 4 | * Copyright (c) 2010-2011, The Linux Foundation. All rights reserved. |
| 5 | * |
| 6 | * This program is free software; you can redistribute it and/or modify |
| 7 | * it under the terms of the GNU General Public License version 2 and |
| 8 | * only version 2 as published by the Free Software Foundation. |
| 9 | * |
| 10 | * This program is distributed in the hope that it will be useful, |
| 11 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 12 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 13 | * GNU General Public License for more details. |
| 14 | * |
| 15 | * You should have received a copy of the GNU General Public License |
| 16 | * along with this program; if not, write to the Free Software |
| 17 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA |
| 18 | * 02110-1301, USA. |
| 19 | */ |
| 20 | |
| 21 | #include <linux/sched.h> |
| 22 | #include <linux/stacktrace.h> |
| 23 | #include <linux/thread_info.h> |
| 24 | #include <linux/module.h> |
| 25 | |
| 26 | register unsigned long current_frame_pointer asm("r30"); |
| 27 | |
| 28 | struct stackframe { |
| 29 | unsigned long fp; |
| 30 | unsigned long rets; |
| 31 | }; |
| 32 | |
| 33 | /* |
| 34 | * Save stack-backtrace addresses into a stack_trace buffer. |
| 35 | */ |
| 36 | void save_stack_trace(struct stack_trace *trace) |
| 37 | { |
| 38 | unsigned long low, high; |
| 39 | unsigned long fp; |
| 40 | struct stackframe *frame; |
| 41 | int skip = trace->skip; |
| 42 | |
| 43 | low = (unsigned long)task_stack_page(current); |
| 44 | high = low + THREAD_SIZE; |
| 45 | fp = current_frame_pointer; |
| 46 | |
| 47 | while (fp >= low && fp <= (high - sizeof(*frame))) { |
| 48 | frame = (struct stackframe *)fp; |
| 49 | |
| 50 | if (skip) { |
| 51 | skip--; |
| 52 | } else { |
| 53 | trace->entries[trace->nr_entries++] = frame->rets; |
| 54 | if (trace->nr_entries >= trace->max_entries) |
| 55 | break; |
| 56 | } |
| 57 | |
| 58 | /* |
| 59 | * The next frame must be at a higher address than the |
| 60 | * current frame. |
| 61 | */ |
| 62 | low = fp + sizeof(*frame); |
| 63 | fp = frame->fp; |
| 64 | } |
| 65 | } |
| 66 | EXPORT_SYMBOL_GPL(save_stack_trace); |