1*74d04d6fSRichard Kuo /* 2*74d04d6fSRichard Kuo * Stacktrace support for Hexagon 3*74d04d6fSRichard Kuo * 4*74d04d6fSRichard Kuo * Copyright (c) 2010-2011, Code Aurora Forum. All rights reserved. 5*74d04d6fSRichard Kuo * 6*74d04d6fSRichard Kuo * This program is free software; you can redistribute it and/or modify 7*74d04d6fSRichard Kuo * it under the terms of the GNU General Public License version 2 and 8*74d04d6fSRichard Kuo * only version 2 as published by the Free Software Foundation. 9*74d04d6fSRichard Kuo * 10*74d04d6fSRichard Kuo * This program is distributed in the hope that it will be useful, 11*74d04d6fSRichard Kuo * but WITHOUT ANY WARRANTY; without even the implied warranty of 12*74d04d6fSRichard Kuo * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 13*74d04d6fSRichard Kuo * GNU General Public License for more details. 14*74d04d6fSRichard Kuo * 15*74d04d6fSRichard Kuo * You should have received a copy of the GNU General Public License 16*74d04d6fSRichard Kuo * along with this program; if not, write to the Free Software 17*74d04d6fSRichard Kuo * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 18*74d04d6fSRichard Kuo * 02110-1301, USA. 19*74d04d6fSRichard Kuo */ 20*74d04d6fSRichard Kuo 21*74d04d6fSRichard Kuo #include <linux/sched.h> 22*74d04d6fSRichard Kuo #include <linux/stacktrace.h> 23*74d04d6fSRichard Kuo #include <linux/thread_info.h> 24*74d04d6fSRichard Kuo #include <linux/module.h> 25*74d04d6fSRichard Kuo 26*74d04d6fSRichard Kuo register unsigned long current_frame_pointer asm("r30"); 27*74d04d6fSRichard Kuo 28*74d04d6fSRichard Kuo struct stackframe { 29*74d04d6fSRichard Kuo unsigned long fp; 30*74d04d6fSRichard Kuo unsigned long rets; 31*74d04d6fSRichard Kuo }; 32*74d04d6fSRichard Kuo 33*74d04d6fSRichard Kuo /* 34*74d04d6fSRichard Kuo * Save stack-backtrace addresses into a stack_trace buffer. 35*74d04d6fSRichard Kuo */ 36*74d04d6fSRichard Kuo void save_stack_trace(struct stack_trace *trace) 37*74d04d6fSRichard Kuo { 38*74d04d6fSRichard Kuo unsigned long low, high; 39*74d04d6fSRichard Kuo unsigned long fp; 40*74d04d6fSRichard Kuo struct stackframe *frame; 41*74d04d6fSRichard Kuo int skip = trace->skip; 42*74d04d6fSRichard Kuo 43*74d04d6fSRichard Kuo low = (unsigned long)task_stack_page(current); 44*74d04d6fSRichard Kuo high = low + THREAD_SIZE; 45*74d04d6fSRichard Kuo fp = current_frame_pointer; 46*74d04d6fSRichard Kuo 47*74d04d6fSRichard Kuo while (fp >= low && fp <= (high - sizeof(*frame))) { 48*74d04d6fSRichard Kuo frame = (struct stackframe *)fp; 49*74d04d6fSRichard Kuo 50*74d04d6fSRichard Kuo if (skip) { 51*74d04d6fSRichard Kuo skip--; 52*74d04d6fSRichard Kuo } else { 53*74d04d6fSRichard Kuo trace->entries[trace->nr_entries++] = frame->rets; 54*74d04d6fSRichard Kuo if (trace->nr_entries >= trace->max_entries) 55*74d04d6fSRichard Kuo break; 56*74d04d6fSRichard Kuo } 57*74d04d6fSRichard Kuo 58*74d04d6fSRichard Kuo /* 59*74d04d6fSRichard Kuo * The next frame must be at a higher address than the 60*74d04d6fSRichard Kuo * current frame. 61*74d04d6fSRichard Kuo */ 62*74d04d6fSRichard Kuo low = fp + sizeof(*frame); 63*74d04d6fSRichard Kuo fp = frame->fp; 64*74d04d6fSRichard Kuo } 65*74d04d6fSRichard Kuo } 66*74d04d6fSRichard Kuo EXPORT_SYMBOL_GPL(save_stack_trace); 67