sparc/kernel/stacktrace.c

0001 // SPDX-License-Identifier: GPL-2.0-only
0002 #include <linux/sched.h>
0003 #include <linux/sched/debug.h>
0004 #include <linux/stacktrace.h>
0005 #include <linux/thread_info.h>
0006 #include <linux/ftrace.h>
0007 #include <linux/export.h>
0008 #include <asm/ptrace.h>
0009 #include <asm/stacktrace.h>
0010
0011 #include "kstack.h"
0012
0013 static void __save_stack_trace(struct thread_info *tp,
0014                    struct stack_trace *trace,
0015                    bool skip_sched)
0016 {
0017     unsigned long ksp, fp;
0018 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
0019     struct task_struct *t;
0020     int graph = 0;
0021 #endif
0022
0023     if (tp == current_thread_info()) {
0024         stack_trace_flush();
0025         __asm__ __volatile__("mov %%fp, %0" : "=r" (ksp));
0026     } else {
0027         ksp = tp->ksp;
0028     }
0029
0030     fp = ksp + STACK_BIAS;
0031 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
0032     t = tp->task;
0033 #endif
0034     do {
0035         struct sparc_stackf *sf;
0036         struct pt_regs *regs;
0037         unsigned long pc;
0038
0039         if (!kstack_valid(tp, fp))
0040             break;
0041
0042         sf = (struct sparc_stackf *) fp;
0043         regs = (struct pt_regs *) (sf + 1);
0044
0045         if (kstack_is_trap_frame(tp, regs)) {
0046             if (!(regs->tstate & TSTATE_PRIV))
0047                 break;
0048             pc = regs->tpc;
0049             fp = regs->u_regs[UREG_I6] + STACK_BIAS;
0050         } else {
0051             pc = sf->callers_pc;
0052             fp = (unsigned long)sf->fp + STACK_BIAS;
0053         }
0054
0055         if (trace->skip > 0)
0056             trace->skip--;
0057         else if (!skip_sched || !in_sched_functions(pc)) {
0058             trace->entries[trace->nr_entries++] = pc;
0059 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
0060             if ((pc + 8UL) == (unsigned long) &return_to_handler) {
0061                 struct ftrace_ret_stack *ret_stack;
0062                 ret_stack = ftrace_graph_get_ret_stack(t,
0063                                        graph);
0064                 if (ret_stack) {
0065                     pc = ret_stack->ret;
0066                     if (trace->nr_entries <
0067                         trace->max_entries)
0068                         trace->entries[trace->nr_entries++] = pc;
0069                     graph++;
0070                 }
0071             }
0072 #endif
0073         }
0074     } while (trace->nr_entries < trace->max_entries);
0075 }
0076
0077 void save_stack_trace(struct stack_trace *trace)
0078 {
0079     __save_stack_trace(current_thread_info(), trace, false);
0080 }
0081 EXPORT_SYMBOL_GPL(save_stack_trace);
0082
0083 void save_stack_trace_tsk(struct task_struct *tsk, struct stack_trace *trace)
0084 {
0085     struct thread_info *tp = task_thread_info(tsk);
0086
0087     __save_stack_trace(tp, trace, true);
0088 }
0089 EXPORT_SYMBOL_GPL(save_stack_trace_tsk);