arch/sparc/kernel/stacktrace.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 #include <linux/sched.h>
   3 #include <linux/sched/debug.h>
   4 #include <linux/stacktrace.h>
   5 #include <linux/thread_info.h>
   6 #include <linux/ftrace.h>
   7 #include <linux/export.h>
   8 #include <asm/ptrace.h>
   9 #include <asm/stacktrace.h>
  10
  11 #include "kstack.h"
  12
  13 static void __save_stack_trace(struct thread_info *tp,
  14                                struct stack_trace *trace,
  15                                bool skip_sched)
  16 {
  17         unsigned long ksp, fp;
  18 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
  19         struct task_struct *t;
  20         int graph = 0;
  21 #endif
  22
  23         if (tp == current_thread_info()) {
  24                 stack_trace_flush();
  25                 __asm__ __volatile__("mov %%fp, %0" : "=r" (ksp));
  26         } else {
  27                 ksp = tp->ksp;
  28         }
  29
  30         fp = ksp + STACK_BIAS;
  31 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
  32         t = tp->task;
  33 #endif
  34         do {
  35                 struct sparc_stackf *sf;
  36                 struct pt_regs *regs;
  37                 unsigned long pc;
  38
  39                 if (!kstack_valid(tp, fp))
  40                         break;
  41
  42                 sf = (struct sparc_stackf *) fp;
  43                 regs = (struct pt_regs *) (sf + 1);
  44
  45                 if (kstack_is_trap_frame(tp, regs)) {
  46                         if (!(regs->tstate & TSTATE_PRIV))
  47                                 break;
  48                         pc = regs->tpc;
  49                         fp = regs->u_regs[UREG_I6] + STACK_BIAS;
  50                 } else {
  51                         pc = sf->callers_pc;
  52                         fp = (unsigned long)sf->fp + STACK_BIAS;
  53                 }
  54
  55                 if (trace->skip > 0)
  56                         trace->skip--;
  57                 else if (!skip_sched || !in_sched_functions(pc)) {
  58                         trace->entries[trace->nr_entries++] = pc;
  59 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
  60                         if ((pc + 8UL) == (unsigned long) &return_to_handler) {
  61                                 struct ftrace_ret_stack *ret_stack;
  62                                 ret_stack = ftrace_graph_get_ret_stack(t,
  63                                                                        graph);
  64                                 if (ret_stack) {
  65                                         pc = ret_stack->ret;
  66                                         if (trace->nr_entries <
  67                                             trace->max_entries)
  68                                                 trace->entries[trace->nr_entries++] = pc;
  69                                         graph++;
  70                                 }
  71                         }
  72 #endif
  73                 }
  74         } while (trace->nr_entries < trace->max_entries);
  75 }
  76
  77 void save_stack_trace(struct stack_trace *trace)
  78 {
  79         __save_stack_trace(current_thread_info(), trace, false);
  80 }
  81 EXPORT_SYMBOL_GPL(save_stack_trace);
  82
  83 void save_stack_trace_tsk(struct task_struct *tsk, struct stack_trace *trace)
  84 {
  85         struct thread_info *tp = task_thread_info(tsk);
  86
  87         __save_stack_trace(tp, trace, true);
  88 }
  89 EXPORT_SYMBOL_GPL(save_stack_trace_tsk);