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