1 #include <linux/sched.h> 2 #include <linux/ftrace.h> 3 #include <asm/ptrace.h> 4 #include <asm/bitops.h> 5 #include <asm/stacktrace.h> 6 #include <asm/unwind.h> 7 8 unsigned long unwind_get_return_address(struct unwind_state *state) 9 { 10 unsigned long addr; 11 12 if (unwind_done(state)) 13 return 0; 14 15 addr = READ_ONCE_NOCHECK(*state->sp); 16 17 return ftrace_graph_ret_addr(state->task, &state->graph_idx, 18 addr, state->sp); 19 } 20 EXPORT_SYMBOL_GPL(unwind_get_return_address); 21 22 bool unwind_next_frame(struct unwind_state *state) 23 { 24 struct stack_info *info = &state->stack_info; 25 26 if (unwind_done(state)) 27 return false; 28 29 do { 30 for (state->sp++; state->sp < info->end; state->sp++) { 31 unsigned long addr = READ_ONCE_NOCHECK(*state->sp); 32 33 if (__kernel_text_address(addr)) 34 return true; 35 } 36 37 state->sp = info->next_sp; 38 39 } while (!get_stack_info(state->sp, state->task, info, 40 &state->stack_mask)); 41 42 return false; 43 } 44 EXPORT_SYMBOL_GPL(unwind_next_frame); 45 46 void __unwind_start(struct unwind_state *state, struct task_struct *task, 47 struct pt_regs *regs, unsigned long *first_frame) 48 { 49 memset(state, 0, sizeof(*state)); 50 51 state->task = task; 52 state->sp = first_frame; 53 54 get_stack_info(first_frame, state->task, &state->stack_info, 55 &state->stack_mask); 56 57 /* 58 * The caller can provide the address of the first frame directly 59 * (first_frame) or indirectly (regs->sp) to indicate which stack frame 60 * to start unwinding at. Skip ahead until we reach it. 61 */ 62 if (!unwind_done(state) && 63 (!on_stack(&state->stack_info, first_frame, sizeof(long)) || 64 !__kernel_text_address(*first_frame))) 65 unwind_next_frame(state); 66 } 67 EXPORT_SYMBOL_GPL(__unwind_start); 68