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); 67