linux/arch/openrisc/kernel/stacktrace.c
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   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 */
  25static void
  26save_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
  42void save_stack_trace(struct stack_trace *trace)
  43{
  44        unwind_stack(trace, (unsigned long *) &trace, save_stack_address);
  45}
  46EXPORT_SYMBOL_GPL(save_stack_trace);
  47
  48static void
  49save_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
  68void 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}
  92EXPORT_SYMBOL_GPL(save_stack_trace_tsk);
  93
  94void
  95save_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}
 100EXPORT_SYMBOL_GPL(save_stack_trace_regs);
 101