| /* |
| * Copyright (C) 2008 ARM Limited |
| * Copyright (C) 2014 Regents of the University of California |
| * |
| * This program is free software; you can redistribute it and/or modify |
| * it under the terms of the GNU General Public License version 2 as |
| * published by the Free Software Foundation. |
| * |
| * This program is distributed in the hope that it will be useful, |
| * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| * GNU General Public License for more details. |
| */ |
| |
| #include <linux/export.h> |
| #include <linux/kallsyms.h> |
| #include <linux/sched.h> |
| #include <linux/sched/debug.h> |
| #include <linux/sched/task_stack.h> |
| #include <linux/stacktrace.h> |
| |
| #ifdef CONFIG_FRAME_POINTER |
| |
| struct stackframe { |
| unsigned long fp; |
| unsigned long ra; |
| }; |
| |
| static void notrace walk_stackframe(struct task_struct *task, |
| struct pt_regs *regs, bool (*fn)(unsigned long, void *), void *arg) |
| { |
| unsigned long fp, sp, pc; |
| |
| if (regs) { |
| fp = GET_FP(regs); |
| sp = GET_USP(regs); |
| pc = GET_IP(regs); |
| } else if (task == NULL || task == current) { |
| const register unsigned long current_sp __asm__ ("sp"); |
| fp = (unsigned long)__builtin_frame_address(0); |
| sp = current_sp; |
| pc = (unsigned long)walk_stackframe; |
| } else { |
| /* task blocked in __switch_to */ |
| fp = task->thread.s[0]; |
| sp = task->thread.sp; |
| pc = task->thread.ra; |
| } |
| |
| for (;;) { |
| unsigned long low, high; |
| struct stackframe *frame; |
| |
| if (unlikely(!__kernel_text_address(pc) || fn(pc, arg))) |
| break; |
| |
| /* Validate frame pointer */ |
| low = sp + sizeof(struct stackframe); |
| high = ALIGN(sp, THREAD_SIZE); |
| if (unlikely(fp < low || fp > high || fp & 0x7)) |
| break; |
| /* Unwind stack frame */ |
| frame = (struct stackframe *)fp - 1; |
| sp = fp; |
| fp = frame->fp; |
| pc = frame->ra - 0x4; |
| } |
| } |
| |
| #else /* !CONFIG_FRAME_POINTER */ |
| |
| static void notrace walk_stackframe(struct task_struct *task, |
| struct pt_regs *regs, bool (*fn)(unsigned long, void *), void *arg) |
| { |
| unsigned long sp, pc; |
| unsigned long *ksp; |
| |
| if (regs) { |
| sp = GET_USP(regs); |
| pc = GET_IP(regs); |
| } else if (task == NULL || task == current) { |
| const register unsigned long current_sp __asm__ ("sp"); |
| sp = current_sp; |
| pc = (unsigned long)walk_stackframe; |
| } else { |
| /* task blocked in __switch_to */ |
| sp = task->thread.sp; |
| pc = task->thread.ra; |
| } |
| |
| if (unlikely(sp & 0x7)) |
| return; |
| |
| ksp = (unsigned long *)sp; |
| while (!kstack_end(ksp)) { |
| if (__kernel_text_address(pc) && unlikely(fn(pc, arg))) |
| break; |
| pc = (*ksp++) - 0x4; |
| } |
| } |
| |
| #endif /* CONFIG_FRAME_POINTER */ |
| |
| |
| static bool print_trace_address(unsigned long pc, void *arg) |
| { |
| print_ip_sym(pc); |
| return false; |
| } |
| |
| void show_stack(struct task_struct *task, unsigned long *sp) |
| { |
| pr_cont("Call Trace:\n"); |
| walk_stackframe(task, NULL, print_trace_address, NULL); |
| } |
| |
| |
| static bool save_wchan(unsigned long pc, void *arg) |
| { |
| if (!in_sched_functions(pc)) { |
| unsigned long *p = arg; |
| *p = pc; |
| return true; |
| } |
| return false; |
| } |
| |
| unsigned long get_wchan(struct task_struct *task) |
| { |
| unsigned long pc = 0; |
| |
| if (likely(task && task != current && task->state != TASK_RUNNING)) |
| walk_stackframe(task, NULL, save_wchan, &pc); |
| return pc; |
| } |
| |
| |
| #ifdef CONFIG_STACKTRACE |
| |
| static bool __save_trace(unsigned long pc, void *arg, bool nosched) |
| { |
| struct stack_trace *trace = arg; |
| |
| if (unlikely(nosched && in_sched_functions(pc))) |
| return false; |
| if (unlikely(trace->skip > 0)) { |
| trace->skip--; |
| return false; |
| } |
| |
| trace->entries[trace->nr_entries++] = pc; |
| return (trace->nr_entries >= trace->max_entries); |
| } |
| |
| static bool save_trace(unsigned long pc, void *arg) |
| { |
| return __save_trace(pc, arg, false); |
| } |
| |
| /* |
| * Save stack-backtrace addresses into a stack_trace buffer. |
| */ |
| void save_stack_trace_tsk(struct task_struct *tsk, struct stack_trace *trace) |
| { |
| walk_stackframe(tsk, NULL, save_trace, trace); |
| if (trace->nr_entries < trace->max_entries) |
| trace->entries[trace->nr_entries++] = ULONG_MAX; |
| } |
| EXPORT_SYMBOL_GPL(save_stack_trace_tsk); |
| |
| void save_stack_trace(struct stack_trace *trace) |
| { |
| save_stack_trace_tsk(NULL, trace); |
| } |
| EXPORT_SYMBOL_GPL(save_stack_trace); |
| |
| #endif /* CONFIG_STACKTRACE */ |