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 unsigned long *unwind_get_return_address_ptr(struct unwind_state *state) 23 { 24 return NULL; 25 } 26 27 bool unwind_next_frame(struct unwind_state *state) 28 { 29 struct stack_info *info = &state->stack_info; 30 31 if (unwind_done(state)) 32 return false; 33 34 do { 35 for (state->sp++; state->sp < info->end; state->sp++) { 36 unsigned long addr = READ_ONCE_NOCHECK(*state->sp); 37 38 if (__kernel_text_address(addr)) 39 return true; 40 } 41 42 state->sp = PTR_ALIGN(info->next_sp, sizeof(long)); 43 44 } while (!get_stack_info(state->sp, state->task, info, 45 &state->stack_mask)); 46 47 return false; 48 } 49 EXPORT_SYMBOL_GPL(unwind_next_frame); 50 51 void __unwind_start(struct unwind_state *state, struct task_struct *task, 52 struct pt_regs *regs, unsigned long *first_frame) 53 { 54 memset(state, 0, sizeof(*state)); 55 56 state->task = task; 57 state->sp = PTR_ALIGN(first_frame, sizeof(long)); 58 59 get_stack_info(first_frame, state->task, &state->stack_info, 60 &state->stack_mask); 61 62 /* 63 * The caller can provide the address of the first frame directly 64 * (first_frame) or indirectly (regs->sp) to indicate which stack frame 65 * to start unwinding at. Skip ahead until we reach it. 66 */ 67 if (!unwind_done(state) && 68 (!on_stack(&state->stack_info, first_frame, sizeof(long)) || 69 !__kernel_text_address(*first_frame))) 70 unwind_next_frame(state); 71 } 72 EXPORT_SYMBOL_GPL(__unwind_start); 73