arch/um/kernel/stacktrace.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Copyright (C) 2001 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
   4  * Copyright (C) 2013 Richard Weinberger <richard@nod.at>
   5  * Copyright (C) 2014 Google Inc., Author: Daniel Walter <dwalter@google.com>
   6  */
   7
   8 #include <linux/kallsyms.h>
   9 #include <linux/kernel.h>
  10 #include <linux/sched.h>
  11 #include <linux/stacktrace.h>
  12 #include <linux/module.h>
  13 #include <linux/uaccess.h>
  14 #include <asm/stacktrace.h>
  15
  16 void dump_trace(struct task_struct *tsk,
  17                 const struct stacktrace_ops *ops,
  18                 void *data)
  19 {
  20         int reliable = 0;
  21         unsigned long *sp, bp, addr;
  22         struct pt_regs *segv_regs = tsk->thread.segv_regs;
  23         struct stack_frame *frame;
  24
  25         bp = get_frame_pointer(tsk, segv_regs);
  26         sp = get_stack_pointer(tsk, segv_regs);
  27
  28         frame = (struct stack_frame *)bp;
  29         while (((long) sp & (THREAD_SIZE-1)) != 0) {
  30                 addr = *sp;
  31                 if (__kernel_text_address(addr)) {
  32                         reliable = 0;
  33                         if ((unsigned long) sp == bp + sizeof(long)) {
  34                                 frame = frame ? frame->next_frame : NULL;
  35                                 bp = (unsigned long)frame;
  36                                 reliable = 1;
  37                         }
  38                         ops->address(data, addr, reliable);
  39                 }
  40                 sp++;
  41         }
  42 }
  43
  44 static void save_addr(void *data, unsigned long address, int reliable)
  45 {
  46         struct stack_trace *trace = data;
  47
  48         if (!reliable)
  49                 return;
  50         if (trace->nr_entries >= trace->max_entries)
  51                 return;
  52
  53         trace->entries[trace->nr_entries++] = address;
  54 }
  55
  56 static const struct stacktrace_ops dump_ops = {
  57         .address = save_addr
  58 };
  59
  60 static void __save_stack_trace(struct task_struct *tsk, struct stack_trace *trace)
  61 {
  62         dump_trace(tsk, &dump_ops, trace);
  63 }
  64
  65 void save_stack_trace(struct stack_trace *trace)
  66 {
  67         __save_stack_trace(current, trace);
  68 }
  69 EXPORT_SYMBOL_GPL(save_stack_trace);
  70
  71 void save_stack_trace_tsk(struct task_struct *tsk, struct stack_trace *trace)
  72 {
  73         __save_stack_trace(tsk, trace);
  74 }
  75 EXPORT_SYMBOL_GPL(save_stack_trace_tsk);