1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * Stacktrace support for Hexagon 4 * 5 * Copyright (c) 2010-2011, The Linux Foundation. All rights reserved. 6 */ 7 8 #include <linux/sched.h> 9 #include <linux/sched/task_stack.h> 10 #include <linux/stacktrace.h> 11 #include <linux/thread_info.h> 12 #include <linux/module.h> 13 14 register unsigned long current_frame_pointer asm("r30"); 15 16 struct stackframe { 17 unsigned long fp; 18 unsigned long rets; 19 }; 20 21 /* 22 * Save stack-backtrace addresses into a stack_trace buffer. 23 */ 24 void save_stack_trace(struct stack_trace *trace) 25 { 26 unsigned long low, high; 27 unsigned long fp; 28 struct stackframe *frame; 29 int skip = trace->skip; 30 31 low = (unsigned long)task_stack_page(current); 32 high = low + THREAD_SIZE; 33 fp = current_frame_pointer; 34 35 while (fp >= low && fp <= (high - sizeof(*frame))) { 36 frame = (struct stackframe *)fp; 37 38 if (skip) { 39 skip--; 40 } else { 41 trace->entries[trace->nr_entries++] = frame->rets; 42 if (trace->nr_entries >= trace->max_entries) 43 break; 44 } 45 46 /* 47 * The next frame must be at a higher address than the 48 * current frame. 49 */ 50 low = fp + sizeof(*frame); 51 fp = frame->fp; 52 } 53 } 54 EXPORT_SYMBOL_GPL(save_stack_trace); 55