1 /* SPDX-License-Identifier: GPL-2.0 */ 2 /* 3 * Most of this ideas comes from x86. 4 * 5 * Copyright (C) 2022 Loongson Technology Corporation Limited 6 */ 7 #ifndef _ASM_UNWIND_H 8 #define _ASM_UNWIND_H 9 10 #include <linux/sched.h> 11 #include <linux/ftrace.h> 12 13 #include <asm/ptrace.h> 14 #include <asm/stacktrace.h> 15 16 enum unwinder_type { 17 UNWINDER_GUESS, 18 UNWINDER_PROLOGUE, 19 UNWINDER_ORC, 20 }; 21 22 struct unwind_state { 23 char type; /* UNWINDER_XXX */ 24 struct stack_info stack_info; 25 struct task_struct *task; 26 bool first, error, reset; 27 int graph_idx; 28 unsigned long sp, fp, pc, ra; 29 }; 30 31 bool default_next_frame(struct unwind_state *state); 32 33 void unwind_start(struct unwind_state *state, 34 struct task_struct *task, struct pt_regs *regs); 35 bool unwind_next_frame(struct unwind_state *state); 36 unsigned long unwind_get_return_address(struct unwind_state *state); 37 38 static inline bool unwind_done(struct unwind_state *state) 39 { 40 return state->stack_info.type == STACK_TYPE_UNKNOWN; 41 } 42 43 static inline bool unwind_error(struct unwind_state *state) 44 { 45 return state->error; 46 } 47 48 #define GRAPH_FAKE_OFFSET (sizeof(struct pt_regs) - offsetof(struct pt_regs, regs[1])) 49 50 static inline unsigned long unwind_graph_addr(struct unwind_state *state, 51 unsigned long pc, unsigned long cfa) 52 { 53 return ftrace_graph_ret_addr(state->task, &state->graph_idx, 54 pc, (unsigned long *)(cfa - GRAPH_FAKE_OFFSET)); 55 } 56 57 static __always_inline void __unwind_start(struct unwind_state *state, 58 struct task_struct *task, struct pt_regs *regs) 59 { 60 memset(state, 0, sizeof(*state)); 61 if (regs) { 62 state->sp = regs->regs[3]; 63 state->pc = regs->csr_era; 64 state->ra = regs->regs[1]; 65 state->fp = regs->regs[22]; 66 } else if (task && task != current) { 67 state->sp = thread_saved_fp(task); 68 state->pc = thread_saved_ra(task); 69 state->ra = 0; 70 state->fp = 0; 71 } else { 72 state->sp = (unsigned long)__builtin_frame_address(0); 73 state->pc = (unsigned long)__builtin_return_address(0); 74 state->ra = 0; 75 state->fp = 0; 76 } 77 state->task = task; 78 get_stack_info(state->sp, state->task, &state->stack_info); 79 state->pc = unwind_graph_addr(state, state->pc, state->sp); 80 } 81 82 static __always_inline unsigned long __unwind_get_return_address(struct unwind_state *state) 83 { 84 if (unwind_done(state)) 85 return 0; 86 87 return __kernel_text_address(state->pc) ? state->pc : 0; 88 } 89 90 #ifdef CONFIG_UNWINDER_ORC 91 void unwind_init(void); 92 void unwind_module_init(struct module *mod, void *orc_ip, size_t orc_ip_size, void *orc, size_t orc_size); 93 #else 94 static inline void unwind_init(void) {} 95 static inline void unwind_module_init(struct module *mod, void *orc_ip, size_t orc_ip_size, void *orc, size_t orc_size) {} 96 #endif 97 98 #endif /* _ASM_UNWIND_H */ 99