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/sched/task_stack.h>
  17 #include <linux/stacktrace.h>
  18
  19 #include <asm/processor.h>
  20 #include <asm/unwinder.h>
  21
  22 /*
  23  * Save stack-backtrace addresses into a stack_trace buffer.
  24  */
  25 static void
  26 save_stack_address(void *data, unsigned long addr, int reliable)
  27 {
  28         struct stack_trace *trace = data;
  29
  30         if (!reliable)
  31                 return;
  32
  33         if (trace->skip > 0) {
  34                 trace->skip--;
  35                 return;
  36         }
  37
  38         if (trace->nr_entries < trace->max_entries)
  39                 trace->entries[trace->nr_entries++] = addr;
  40 }
  41
  42 void save_stack_trace(struct stack_trace *trace)
  43 {
  44         unwind_stack(trace, (unsigned long *) &trace, save_stack_address);
  45 }
  46 EXPORT_SYMBOL_GPL(save_stack_trace);
  47
  48 static void
  49 save_stack_address_nosched(void *data, unsigned long addr, int reliable)
  50 {
  51         struct stack_trace *trace = (struct stack_trace *)data;
  52
  53         if (!reliable)
  54                 return;
  55
  56         if (in_sched_functions(addr))
  57                 return;
  58
  59         if (trace->skip > 0) {
  60                 trace->skip--;
  61                 return;
  62         }
  63
  64         if (trace->nr_entries < trace->max_entries)
  65                 trace->entries[trace->nr_entries++] = addr;
  66 }
  67
  68 void save_stack_trace_tsk(struct task_struct *tsk, struct stack_trace *trace)
  69 {
  70         unsigned long *sp = NULL;
  71
  72         if (!try_get_task_stack(tsk))
  73                 return;
  74
  75         if (tsk == current)
  76                 sp = (unsigned long *) &sp;
  77         else {
  78                 unsigned long ksp;
  79
  80                 /* Locate stack from kernel context */
  81                 ksp = task_thread_info(tsk)->ksp;
  82                 ksp += STACK_FRAME_OVERHEAD;    /* redzone */
  83                 ksp += sizeof(struct pt_regs);
  84
  85                 sp = (unsigned long *) ksp;
  86         }
  87
  88         unwind_stack(trace, sp, save_stack_address_nosched);
  89
  90         put_task_stack(tsk);
  91 }
  92 EXPORT_SYMBOL_GPL(save_stack_trace_tsk);
  93
  94 void
  95 save_stack_trace_regs(struct pt_regs *regs, struct stack_trace *trace)
  96 {
  97         unwind_stack(trace, (unsigned long *) regs->sp,
  98                      save_stack_address_nosched);
  99 }
 100 EXPORT_SYMBOL_GPL(save_stack_trace_regs);