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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 | // SPDX-License-Identifier: GPL-2.0-only /* * Copyright (C) 2008 ARM Limited * Copyright (C) 2014 Regents of the University of California */ #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> #include <linux/ftrace.h> #include <asm/stacktrace.h> #ifdef CONFIG_FRAME_POINTER extern asmlinkage void ret_from_exception(void); void notrace walk_stackframe(struct task_struct *task, struct pt_regs *regs, bool (*fn)(void *, unsigned long), void *arg) { unsigned long fp, sp, pc; int level = 0; if (regs) { fp = frame_pointer(regs); sp = user_stack_pointer(regs); pc = instruction_pointer(regs); } else if (task == NULL || task == current) { fp = (unsigned long)__builtin_frame_address(0); sp = current_stack_pointer; 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) || (level++ >= 1 && !fn(arg, pc)))) 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; if (regs && (regs->epc == pc) && (frame->fp & 0x7)) { fp = frame->ra; pc = regs->ra; } else { fp = frame->fp; pc = ftrace_graph_ret_addr(current, NULL, frame->ra, &frame->ra); if (pc == (unsigned long)ret_from_exception) { if (unlikely(!__kernel_text_address(pc) || !fn(arg, pc))) break; pc = ((struct pt_regs *)sp)->epc; fp = ((struct pt_regs *)sp)->s0; } } } } #else /* !CONFIG_FRAME_POINTER */ void notrace walk_stackframe(struct task_struct *task, struct pt_regs *regs, bool (*fn)(void *, unsigned long), void *arg) { unsigned long sp, pc; unsigned long *ksp; if (regs) { sp = user_stack_pointer(regs); pc = instruction_pointer(regs); } else if (task == NULL || task == current) { sp = current_stack_pointer; 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(arg, pc))) break; pc = (*ksp++) - 0x4; } } #endif /* CONFIG_FRAME_POINTER */ static bool print_trace_address(void *arg, unsigned long pc) { const char *loglvl = arg; print_ip_sym(loglvl, pc); return true; } noinline void dump_backtrace(struct pt_regs *regs, struct task_struct *task, const char *loglvl) { walk_stackframe(task, regs, print_trace_address, (void *)loglvl); } void show_stack(struct task_struct *task, unsigned long *sp, const char *loglvl) { pr_cont("%sCall Trace:\n", loglvl); dump_backtrace(NULL, task, loglvl); } static bool save_wchan(void *arg, unsigned long pc) { if (!in_sched_functions(pc)) { unsigned long *p = arg; *p = pc; return false; } return true; } unsigned long __get_wchan(struct task_struct *task) { unsigned long pc = 0; if (!try_get_task_stack(task)) return 0; walk_stackframe(task, NULL, save_wchan, &pc); put_task_stack(task); return pc; } noinline void arch_stack_walk(stack_trace_consume_fn consume_entry, void *cookie, struct task_struct *task, struct pt_regs *regs) { walk_stackframe(task, regs, consume_entry, cookie); } |