arch/um/kernel/stacktrace.c

   1 /*
   2  * Copyright (C) 2001 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
   3  * Copyright (C) 2013 Richard Weinberger <richard@nod.at>
   4  * Copyright (C) 2014 Google Inc., Author: Daniel Walter <dwalter@google.com>
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License version 2 as
   8  * published by the Free Software Foundation.
   9  */
  10
  11 #include <linux/kallsyms.h>
  12 #include <linux/kernel.h>
  13 #include <linux/sched.h>
  14 #include <linux/stacktrace.h>
  15 #include <linux/module.h>
  16 #include <linux/uaccess.h>
  17 #include <asm/stacktrace.h>
  18
  19 void dump_trace(struct task_struct *tsk,
  20                 const struct stacktrace_ops *ops,
  21                 void *data)
  22 {
  23         int reliable = 0;
  24         unsigned long *sp, bp, addr;
  25         struct pt_regs *segv_regs = tsk->thread.segv_regs;
  26         struct stack_frame *frame;
  27
  28         bp = get_frame_pointer(tsk, segv_regs);
  29         sp = get_stack_pointer(tsk, segv_regs);
  30
  31         frame = (struct stack_frame *)bp;
  32         while (((long) sp & (THREAD_SIZE-1)) != 0) {
  33                 addr = *sp;
  34                 if (__kernel_text_address(addr)) {
  35                         reliable = 0;
  36                         if ((unsigned long) sp == bp + sizeof(long)) {
  37                                 frame = frame ? frame->next_frame : NULL;
  38                                 bp = (unsigned long)frame;
  39                                 reliable = 1;
  40                         }
  41                         ops->address(data, addr, reliable);
  42                 }
  43                 sp++;
  44         }
  45 }
  46
  47 static void save_addr(void *data, unsigned long address, int reliable)
  48 {
  49         struct stack_trace *trace = data;
  50
  51         if (!reliable)
  52                 return;
  53         if (trace->nr_entries >= trace->max_entries)
  54                 return;
  55
  56         trace->entries[trace->nr_entries++] = address;
  57 }
  58
  59 static const struct stacktrace_ops dump_ops = {
  60         .address = save_addr
  61 };
  62
  63 static void __save_stack_trace(struct task_struct *tsk, struct stack_trace *trace)
  64 {
  65         dump_trace(tsk, &dump_ops, trace);
  66         if (trace->nr_entries < trace->max_entries)
  67                 trace->entries[trace->nr_entries++] = ULONG_MAX;
  68 }
  69
  70 void save_stack_trace(struct stack_trace *trace)
  71 {
  72         __save_stack_trace(current, trace);
  73 }
  74 EXPORT_SYMBOL_GPL(save_stack_trace);
  75
  76 void save_stack_trace_tsk(struct task_struct *tsk, struct stack_trace *trace)
  77 {
  78         __save_stack_trace(tsk, trace);
  79 }
  80 EXPORT_SYMBOL_GPL(save_stack_trace_tsk);