arch/openrisc/kernel/stacktrace.c

   1 /*
   2  * Stack trace utility for OpenRISC
   3  *
   4  * Copyright (C) 2017 Stafford Horne <shorne@gmail.com>
   5  *
   6  * This file is licensed under the terms of the GNU General Public License
   7  * version 2.  This program is licensed "as is" without any warranty of any
   8  * kind, whether express or implied.
   9  *
  10  * Losely based on work from sh and powerpc.
  11  */
  12
  13 #include <linux/export.h>
  14 #include <linux/sched.h>
  15 #include <linux/sched/debug.h>
  16 #include <linux/stacktrace.h>
  17
  18 #include <asm/processor.h>
  19 #include <asm/unwinder.h>
  20
  21 /*
  22  * Save stack-backtrace addresses into a stack_trace buffer.
  23  */
  24 static void
  25 save_stack_address(void *data, unsigned long addr, int reliable)
  26 {
  27         struct stack_trace *trace = data;
  28
  29         if (!reliable)
  30                 return;
  31
  32         if (trace->skip > 0) {
  33                 trace->skip--;
  34                 return;
  35         }
  36
  37         if (trace->nr_entries < trace->max_entries)
  38                 trace->entries[trace->nr_entries++] = addr;
  39 }
  40
  41 void save_stack_trace(struct stack_trace *trace)
  42 {
  43         unwind_stack(trace, (unsigned long *) &trace, save_stack_address);
  44 }
  45 EXPORT_SYMBOL_GPL(save_stack_trace);
  46
  47 static void
  48 save_stack_address_nosched(void *data, unsigned long addr, int reliable)
  49 {
  50         struct stack_trace *trace = (struct stack_trace *)data;
  51
  52         if (!reliable)
  53                 return;
  54
  55         if (in_sched_functions(addr))
  56                 return;
  57
  58         if (trace->skip > 0) {
  59                 trace->skip--;
  60                 return;
  61         }
  62
  63         if (trace->nr_entries < trace->max_entries)
  64                 trace->entries[trace->nr_entries++] = addr;
  65 }
  66
  67 void save_stack_trace_tsk(struct task_struct *tsk, struct stack_trace *trace)
  68 {
  69         unsigned long *sp = NULL;
  70
  71         if (tsk == current)
  72                 sp = (unsigned long *) &sp;
  73         else
  74                 sp = (unsigned long *) KSTK_ESP(tsk);
  75
  76         unwind_stack(trace, sp, save_stack_address_nosched);
  77 }
  78 EXPORT_SYMBOL_GPL(save_stack_trace_tsk);
  79
  80 void
  81 save_stack_trace_regs(struct pt_regs *regs, struct stack_trace *trace)
  82 {
  83         unwind_stack(trace, (unsigned long *) regs->sp,
  84                      save_stack_address_nosched);
  85 }
  86 EXPORT_SYMBOL_GPL(save_stack_trace_regs);