1 // SPDX-License-Identifier: GPL-2.0-only 2 #include <linux/sched.h> 3 #include <linux/ftrace.h> 4 #include <asm/ptrace.h> 5 #include <asm/bitops.h> 6 #include <asm/stacktrace.h> 7 #include <asm/unwind.h> 8 9 unsigned long unwind_get_return_address(struct unwind_state *state) 10 { 11 unsigned long addr; 12 13 if (unwind_done(state)) 14 return 0; 15 16 addr = READ_ONCE_NOCHECK(*state->sp); 17 18 return ftrace_graph_ret_addr(state->task, &state->graph_idx, 19 addr, state->sp); 20 } 21 EXPORT_SYMBOL_GPL(unwind_get_return_address); 22 23 unsigned long *unwind_get_return_address_ptr(struct unwind_state *state) 24 { 25 return NULL; 26 } 27 28 bool unwind_next_frame(struct unwind_state *state) 29 { 30 struct stack_info *info = &state->stack_info; 31 32 if (unwind_done(state)) 33 return false; 34 35 do { 36 for (state->sp++; state->sp < info->end; state->sp++) { 37 unsigned long addr = READ_ONCE_NOCHECK(*state->sp); 38 39 if (__kernel_text_address(addr)) 40 return true; 41 } 42 43 state->sp = PTR_ALIGN(info->next_sp, sizeof(long)); 44 45 } while (!get_stack_info(state->sp, state->task, info, 46 &state->stack_mask)); 47 48 return false; 49 } 50 EXPORT_SYMBOL_GPL(unwind_next_frame); 51 52 void __unwind_start(struct unwind_state *state, struct task_struct *task, 53 struct pt_regs *regs, unsigned long *first_frame) 54 { 55 memset(state, 0, sizeof(*state)); 56 57 state->task = task; 58 state->sp = PTR_ALIGN(first_frame, sizeof(long)); 59 60 get_stack_info(first_frame, state->task, &state->stack_info, 61 &state->stack_mask); 62 63 /* 64 * The caller can provide the address of the first frame directly 65 * (first_frame) or indirectly (regs->sp) to indicate which stack frame 66 * to start unwinding at. Skip ahead until we reach it. 67 */ 68 if (!unwind_done(state) && 69 (!on_stack(&state->stack_info, first_frame, sizeof(long)) || 70 !__kernel_text_address(*first_frame))) 71 unwind_next_frame(state); 72 } 73 EXPORT_SYMBOL_GPL(__unwind_start); 74