174d04d6fSRichard Kuo /* 274d04d6fSRichard Kuo * Stacktrace support for Hexagon 374d04d6fSRichard Kuo * 4e1858b2aSRichard Kuo * Copyright (c) 2010-2011, The Linux Foundation. All rights reserved. 574d04d6fSRichard Kuo * 674d04d6fSRichard Kuo * This program is free software; you can redistribute it and/or modify 774d04d6fSRichard Kuo * it under the terms of the GNU General Public License version 2 and 874d04d6fSRichard Kuo * only version 2 as published by the Free Software Foundation. 974d04d6fSRichard Kuo * 1074d04d6fSRichard Kuo * This program is distributed in the hope that it will be useful, 1174d04d6fSRichard Kuo * but WITHOUT ANY WARRANTY; without even the implied warranty of 1274d04d6fSRichard Kuo * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 1374d04d6fSRichard Kuo * GNU General Public License for more details. 1474d04d6fSRichard Kuo * 1574d04d6fSRichard Kuo * You should have received a copy of the GNU General Public License 1674d04d6fSRichard Kuo * along with this program; if not, write to the Free Software 1774d04d6fSRichard Kuo * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 1874d04d6fSRichard Kuo * 02110-1301, USA. 1974d04d6fSRichard Kuo */ 2074d04d6fSRichard Kuo 2174d04d6fSRichard Kuo #include <linux/sched.h> 22*68db0cf1SIngo Molnar #include <linux/sched/task_stack.h> 2374d04d6fSRichard Kuo #include <linux/stacktrace.h> 2474d04d6fSRichard Kuo #include <linux/thread_info.h> 2574d04d6fSRichard Kuo #include <linux/module.h> 2674d04d6fSRichard Kuo 2774d04d6fSRichard Kuo register unsigned long current_frame_pointer asm("r30"); 2874d04d6fSRichard Kuo 2974d04d6fSRichard Kuo struct stackframe { 3074d04d6fSRichard Kuo unsigned long fp; 3174d04d6fSRichard Kuo unsigned long rets; 3274d04d6fSRichard Kuo }; 3374d04d6fSRichard Kuo 3474d04d6fSRichard Kuo /* 3574d04d6fSRichard Kuo * Save stack-backtrace addresses into a stack_trace buffer. 3674d04d6fSRichard Kuo */ 3774d04d6fSRichard Kuo void save_stack_trace(struct stack_trace *trace) 3874d04d6fSRichard Kuo { 3974d04d6fSRichard Kuo unsigned long low, high; 4074d04d6fSRichard Kuo unsigned long fp; 4174d04d6fSRichard Kuo struct stackframe *frame; 4274d04d6fSRichard Kuo int skip = trace->skip; 4374d04d6fSRichard Kuo 4474d04d6fSRichard Kuo low = (unsigned long)task_stack_page(current); 4574d04d6fSRichard Kuo high = low + THREAD_SIZE; 4674d04d6fSRichard Kuo fp = current_frame_pointer; 4774d04d6fSRichard Kuo 4874d04d6fSRichard Kuo while (fp >= low && fp <= (high - sizeof(*frame))) { 4974d04d6fSRichard Kuo frame = (struct stackframe *)fp; 5074d04d6fSRichard Kuo 5174d04d6fSRichard Kuo if (skip) { 5274d04d6fSRichard Kuo skip--; 5374d04d6fSRichard Kuo } else { 5474d04d6fSRichard Kuo trace->entries[trace->nr_entries++] = frame->rets; 5574d04d6fSRichard Kuo if (trace->nr_entries >= trace->max_entries) 5674d04d6fSRichard Kuo break; 5774d04d6fSRichard Kuo } 5874d04d6fSRichard Kuo 5974d04d6fSRichard Kuo /* 6074d04d6fSRichard Kuo * The next frame must be at a higher address than the 6174d04d6fSRichard Kuo * current frame. 6274d04d6fSRichard Kuo */ 6374d04d6fSRichard Kuo low = fp + sizeof(*frame); 6474d04d6fSRichard Kuo fp = frame->fp; 6574d04d6fSRichard Kuo } 6674d04d6fSRichard Kuo } 6774d04d6fSRichard Kuo EXPORT_SYMBOL_GPL(save_stack_trace); 68